Sample records for joint posterior probability

  1. The Estimation of Tree Posterior Probabilities Using Conditional Clade Probability Distributions

    PubMed Central

    Larget, Bret

    2013-01-01

    In this article I introduce the idea of conditional independence of separated subtrees as a principle by which to estimate the posterior probability of trees using conditional clade probability distributions rather than simple sample relative frequencies. I describe an algorithm for these calculations and software which implements these ideas. I show that these alternative calculations are very similar to simple sample relative frequencies for high probability trees but are substantially more accurate for relatively low probability trees. The method allows the posterior probability of unsampled trees to be calculated when these trees contain only clades that are in other sampled trees. Furthermore, the method can be used to estimate the total probability of the set of sampled trees which provides a measure of the thoroughness of a posterior sample. [Bayesian phylogenetics; conditional clade distributions; improved accuracy; posterior probabilities of trees.] PMID:23479066

  2. The estimation of tree posterior probabilities using conditional clade probability distributions.

    PubMed

    Larget, Bret

    2013-07-01

    In this article I introduce the idea of conditional independence of separated subtrees as a principle by which to estimate the posterior probability of trees using conditional clade probability distributions rather than simple sample relative frequencies. I describe an algorithm for these calculations and software which implements these ideas. I show that these alternative calculations are very similar to simple sample relative frequencies for high probability trees but are substantially more accurate for relatively low probability trees. The method allows the posterior probability of unsampled trees to be calculated when these trees contain only clades that are in other sampled trees. Furthermore, the method can be used to estimate the total probability of the set of sampled trees which provides a measure of the thoroughness of a posterior sample.

  3. Posterior probability of linkage and maximal lod score.

    PubMed

    Génin, E; Martinez, M; Clerget-Darpoux, F

    1995-01-01

    To detect linkage between a trait and a marker, Morton (1955) proposed to calculate the lod score z(theta 1) at a given value theta 1 of the recombination fraction. If z(theta 1) reaches +3 then linkage is concluded. However, in practice, lod scores are calculated for different values of the recombination fraction between 0 and 0.5 and the test is based on the maximum value of the lod score Zmax. The impact of this deviation of the test on the probability that in fact linkage does not exist, when linkage was concluded, is documented here. This posterior probability of no linkage can be derived by using Bayes' theorem. It is less than 5% when the lod score at a predetermined theta 1 is used for the test. But, for a Zmax of +3, we showed that it can reach 16.4%. Thus, considering a composite alternative hypothesis instead of a single one decreases the reliability of the test. The reliability decreases rapidly when Zmax is less than +3. Given a Zmax of +2.5, there is a 33% chance that linkage does not exist. Moreover, the posterior probability depends not only on the value of Zmax but also jointly on the family structures and on the genetic model. For a given Zmax, the chance that linkage exists may then vary.

  4. Posterior subtalar joint synoviography and corticosteroid injection in rheumatoid arthritis.

    PubMed Central

    Beaudet, F; Dixon, A S

    1981-01-01

    Ten posterior subtalar joints of 8 patients with rheumatoid arthritis and 12 posterior subtalar joints of 6 cadavers were studied by contrast synoviography. In the rheumatoid group the abnormalities included posterior capsule distension, filling defects caused by hypertrophic synovitis, limited or irregular filling of the anterior recess of the joint in 5 out of 10, and communication with the ankle joint in 3 out of 10. None of the cadaveric joints showed posterior capsule distension or limited or irregular filling of the anterior recess of the joint, but communication with the ankle was present in 2 joints. The joints of the patients were injected with a 1:1 mixture of sodium iothalamate 70% (Conray 420) and triamcinolone hexacetonide (Lederspan) 20 mg/ml. All patients noticed a decrease in and an improvement in walking beginning 24-48 hours after the examination. Quantitative thermography was done immediately before and 1 after injection in 2 patients who showed an improvement in thermographic index. We conclude that hindfoot inflammatory pain arising from the posterior subtalar joint is caused by distension with hypertrophic synovitis which can be difficult to detect clinically. Images PMID:7224686

  5. Multiclass Posterior Probability Twin SVM for Motor Imagery EEG Classification.

    PubMed

    She, Qingshan; Ma, Yuliang; Meng, Ming; Luo, Zhizeng

    2015-01-01

    Motor imagery electroencephalography is widely used in the brain-computer interface systems. Due to inherent characteristics of electroencephalography signals, accurate and real-time multiclass classification is always challenging. In order to solve this problem, a multiclass posterior probability solution for twin SVM is proposed by the ranking continuous output and pairwise coupling in this paper. First, two-class posterior probability model is constructed to approximate the posterior probability by the ranking continuous output techniques and Platt's estimating method. Secondly, a solution of multiclass probabilistic outputs for twin SVM is provided by combining every pair of class probabilities according to the method of pairwise coupling. Finally, the proposed method is compared with multiclass SVM and twin SVM via voting, and multiclass posterior probability SVM using different coupling approaches. The efficacy on the classification accuracy and time complexity of the proposed method has been demonstrated by both the UCI benchmark datasets and real world EEG data from BCI Competition IV Dataset 2a, respectively.

  6. Excluding joint probabilities from quantum theory

    NASA Astrophysics Data System (ADS)

    Allahverdyan, Armen E.; Danageozian, Arshag

    2018-03-01

    Quantum theory does not provide a unique definition for the joint probability of two noncommuting observables, which is the next important question after the Born's probability for a single observable. Instead, various definitions were suggested, e.g., via quasiprobabilities or via hidden-variable theories. After reviewing open issues of the joint probability, we relate it to quantum imprecise probabilities, which are noncontextual and are consistent with all constraints expected from a quantum probability. We study two noncommuting observables in a two-dimensional Hilbert space and show that there is no precise joint probability that applies for any quantum state and is consistent with imprecise probabilities. This contrasts with theorems by Bell and Kochen-Specker that exclude joint probabilities for more than two noncommuting observables, in Hilbert space with dimension larger than two. If measurement contexts are included into the definition, joint probabilities are not excluded anymore, but they are still constrained by imprecise probabilities.

  7. Efficient marginalization to compute protein posterior probabilities from shotgun mass spectrometry data

    PubMed Central

    Serang, Oliver; MacCoss, Michael J.; Noble, William Stafford

    2010-01-01

    The problem of identifying proteins from a shotgun proteomics experiment has not been definitively solved. Identifying the proteins in a sample requires ranking them, ideally with interpretable scores. In particular, “degenerate” peptides, which map to multiple proteins, have made such a ranking difficult to compute. The problem of computing posterior probabilities for the proteins, which can be interpreted as confidence in a protein’s presence, has been especially daunting. Previous approaches have either ignored the peptide degeneracy problem completely, addressed it by computing a heuristic set of proteins or heuristic posterior probabilities, or by estimating the posterior probabilities with sampling methods. We present a probabilistic model for protein identification in tandem mass spectrometry that recognizes peptide degeneracy. We then introduce graph-transforming algorithms that facilitate efficient computation of protein probabilities, even for large data sets. We evaluate our identification procedure on five different well-characterized data sets and demonstrate our ability to efficiently compute high-quality protein posteriors. PMID:20712337

  8. Sacroiliac joint tuberculosis: surgical management by posterior open-window focal debridement and joint fusion.

    PubMed

    Zhu, Guo; Jiang, Li-Yuan; Yi, Zhang; Ping, Li; Duan, Chun-Yue; Yong, Cao; Liu, Jin-Yang; Hu, Jian-Zhong

    2017-11-29

    Sacroiliac joint tuberculosis(SJT) is relatively uncommon, but it may cause severe sacroiliac joint destruction and functional disorder. Few studies in the literature have been presented on SJT, reports of surgical treatment for SJT are even fewer. In this study, we retrospectively reviewed surgical management of patients with severe SJT of 3 different types and proposed to reveal the clinical manifestations and features and aim to determine the efficiency and security of such surgical treatment. We reviewed 17 patients with severe SJT of 3 different types who underwent posterior open-window focal debridement and bone graft for joint fusion. Among them,five patients with anterior sacral abscess had anterior abscess curettage before debridement. Two patients with lumbar vertebral tuberculosis received one-stage posterior tuberculous debridement, interbody fusion and instrumentation. Follow-up was performed 36 months (26 to 45 months) using the following parameters: erythrocyte sedimentation rate(ESR), status of joint bony fusion on CT scan, visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Buttock pain and low back pain were progressively relieved with time. 6 months later, pain was not obvious, and ESR resumed to normal levels within 3 months. Solid fusion of the sacroiliac joint occurred within 12 months in all cases. No complications or recurrence occurred. At final follow-up, all patients had no pain or only minimal discomfort over the affected joint and almost complete functional recovery. Posterior open-window focal debridement and joint fusion is an efficient and secure surgical method to treat severe SJT. If there is an abscess in the front of the sacroiliac joint, anterior abscess curettage should be performed as a supplement.

  9. Joint probabilities and quantum cognition

    NASA Astrophysics Data System (ADS)

    de Barros, J. Acacio

    2012-12-01

    In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

  10. Bayes factor and posterior probability: Complementary statistical evidence to p-value.

    PubMed

    Lin, Ruitao; Yin, Guosheng

    2015-09-01

    As a convention, a p-value is often computed in hypothesis testing and compared with the nominal level of 0.05 to determine whether to reject the null hypothesis. Although the smaller the p-value, the more significant the statistical test, it is difficult to perceive the p-value in a probability scale and quantify it as the strength of the data against the null hypothesis. In contrast, the Bayesian posterior probability of the null hypothesis has an explicit interpretation of how strong the data support the null. We make a comparison of the p-value and the posterior probability by considering a recent clinical trial. The results show that even when we reject the null hypothesis, there is still a substantial probability (around 20%) that the null is true. Not only should we examine whether the data would have rarely occurred under the null hypothesis, but we also need to know whether the data would be rare under the alternative. As a result, the p-value only provides one side of the information, for which the Bayes factor and posterior probability may offer complementary evidence. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Cumulative probability of neodymium: YAG laser posterior capsulotomy after phacoemulsification.

    PubMed

    Ando, Hiroshi; Ando, Nobuyo; Oshika, Tetsuro

    2003-11-01

    To retrospectively analyze the cumulative probability of neodymium:YAG (Nd:YAG) laser posterior capsulotomy after phacoemulsification and to evaluate the risk factors. Ando Eye Clinic, Kanagawa, Japan. In 3997 eyes that had phacoemulsification with an intact continuous curvilinear capsulorhexis, the cumulative probability of posterior capsulotomy was computed by Kaplan-Meier survival analysis and risk factors were analyzed using the Cox proportional hazards regression model. The variables tested were sex; age; type of cataract; preoperative best corrected visual acuity (BCVA); presence of diabetes mellitus, diabetic retinopathy, or retinitis pigmentosa; type of intraocular lens (IOL); and the year the operation was performed. The IOLs were categorized as 3-piece poly(methyl methacrylate) (PMMA), 1-piece PMMA, 3-piece silicone, and acrylic foldable. The cumulative probability of capsulotomy after cataract surgery was 1.95%, 18.50%, and 32.70% at 1, 3, and 5 years, respectively. Positive risk factors included a better preoperative BCVA (P =.0005; risk ratio [RR], 1.7; 95% confidence interval [CI], 1.3-2.5) and the presence of retinitis pigmentosa (P<.0001; RR, 6.6; 95% CI, 3.7-11.6). Women had a significantly greater probability of Nd:YAG laser posterior capsulotomy (P =.016; RR, 1.4; 95% CI, 1.1-1.8). The type of IOL was significantly related to the probability of Nd:YAG laser capsulotomy, with the foldable acrylic IOL having a significantly lower probability of capsulotomy. The 1-piece PMMA IOL had a significantly higher risk than 3-piece PMMA and 3-piece silicone IOLs. The probability of Nd:YAG laser capsulotomy was higher in women, in eyes with a better preoperative BCVA, and in patients with retinitis pigmentosa. The foldable acrylic IOL had a significantly lower probability of capsulotomy.

  12. Translational and rotational knee joint stability in anterior and posterior cruciate-retaining knee arthroplasty.

    PubMed

    Lo, JiaHsuan; Müller, Otto; Dilger, Torsten; Wülker, Nikolaus; Wünschel, Markus

    2011-12-01

    This study investigated passive translational and rotational stability properties of the intact knee joint, after bicruciate-retaining bi-compartmental knee arthroplasty (BKA) and after posterior cruciate retaining total knee arthroplasty (TKA). Fourteen human cadaveric knee specimens were used in this study, and a robotic manipulator with six-axis force/torque sensor was used to test the joint laxity in anterior-posterior translation, valgus-varus, and internal-external rotation. The results show the knee joint stability after bicruciate-retaining BKA is similar to that of the native knee. On the other hand, the PCL-retaining TKA results in inferior joint stability in valgus, varus, external rotation, anterior and, surprisingly, posterior directions. Our findings suggest that, provided functional ligamentous structures, bicruciate-retaining BKA is a biomechanically attractive treatment for joint degenerative disease. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Elastic K-means using posterior probability

    PubMed Central

    Zheng, Aihua; Jiang, Bo; Li, Yan; Zhang, Xuehan; Ding, Chris

    2017-01-01

    The widely used K-means clustering is a hard clustering algorithm. Here we propose a Elastic K-means clustering model (EKM) using posterior probability with soft capability where each data point can belong to multiple clusters fractionally and show the benefit of proposed Elastic K-means. Furthermore, in many applications, besides vector attributes information, pairwise relations (graph information) are also available. Thus we integrate EKM with Normalized Cut graph clustering into a single clustering formulation. Finally, we provide several useful matrix inequalities which are useful for matrix formulations of learning models. Based on these results, we prove the correctness and the convergence of EKM algorithms. Experimental results on six benchmark datasets demonstrate the effectiveness of proposed EKM and its integrated model. PMID:29240756

  14. Elastic K-means using posterior probability.

    PubMed

    Zheng, Aihua; Jiang, Bo; Li, Yan; Zhang, Xuehan; Ding, Chris

    2017-01-01

    The widely used K-means clustering is a hard clustering algorithm. Here we propose a Elastic K-means clustering model (EKM) using posterior probability with soft capability where each data point can belong to multiple clusters fractionally and show the benefit of proposed Elastic K-means. Furthermore, in many applications, besides vector attributes information, pairwise relations (graph information) are also available. Thus we integrate EKM with Normalized Cut graph clustering into a single clustering formulation. Finally, we provide several useful matrix inequalities which are useful for matrix formulations of learning models. Based on these results, we prove the correctness and the convergence of EKM algorithms. Experimental results on six benchmark datasets demonstrate the effectiveness of proposed EKM and its integrated model.

  15. Learning about Posterior Probability: Do Diagrams and Elaborative Interrogation Help?

    ERIC Educational Resources Information Center

    Clinton, Virginia; Alibali, Martha Wagner; Nathan, Mitchel J.

    2016-01-01

    To learn from a text, students must make meaningful connections among related ideas in that text. This study examined the effectiveness of two methods of improving connections--elaborative interrogation and diagrams--in written lessons about posterior probability. Undergraduate students (N = 198) read a lesson in one of three questioning…

  16. The effect of variable size posterior wall acetabular fractures on contact characteristics of the hip joint.

    PubMed

    Olson, S A; Bay, B K; Pollak, A N; Sharkey, N A; Lee, T

    1996-01-01

    The indications for open reduction and internal fixation of posterior wall acetabular fractures associated with a clinically stable hip joint are unclear. In previous work a large posterior wall defect (27% articular surface area) resulted in significant alteration of load transmission across the hip; specifically, there was a transition from evenly distributed loading along the acetabular articular surface to loading concentrated mainly in the superior portion of the articular surface during simulated single leg stance. However, the majority of posterior wall fractures involve a smaller amount of the articular surface. Posterior wall acetabular fractures not associated with instability of the hip are commonly treated nonoperatively. This practice does not account for the size of the posterior wall fracture. To study the biomechanical consequences of variably sized articular defects, a laboratory experiment was conducted evaluating three progressively larger posterior wall defects of the acetabulum during simulated single leg stance using superlow Fuji prescale film (Itochu International, New York): (a) 1/3 articular surface width through a 50 degrees arc along the posterior wall of the acetabulum, (b) 2/3, and (c) 3/3 articular width defects through the same 50 degrees arc along the posterior wall of the acetabulum. In the intact acetabulum, 48% of the total articular contact was located in the superior acetabulum. Twenty-eight percent of articular contact was in the anterior wall region of the acetabulum and 24% in the posterior wall region. After the 1/3 width posterior wall defect, 64% of the articular contact was located in the superior acetabulum (p = 0.0011). The 2/3 width posterior wall defect resulted in 71% of articular contact area being located in the superior acetabulum (p = 0.0006). After the 3/3 width posterior wall defect, 77% of articular contact was located in the superior acetabulum, significantly greater than the intact condition (p < 0

  17. Treatment strategy for sacroiliac joint-related pain at or around the posterior superior iliac spine.

    PubMed

    Murakami, Eiichi; Kurosawa, Daisuke; Aizawa, Toshimi

    2018-02-01

    Pain at or around the posterior superior iliac spine (PSIS) is characteristic of sacroiliac joint (SIJ) -related pain. This pain can be treated by either a peri- or intra-articular injection into the joint, with the former being much easier to perform. We investigated whether peri- or intra-articular injections were more frequently effective in patients with SIJ-related pain, and aimed to create an efficient treatment strategy for SIJ-related pain at or around the PSIS. Prospective case-control study. We evaluated 85 patients with pain at or around the posterior superior iliac spine as indicated by the one finger test. First, we performed a peri-articular sacroiliac joint injection. If it was ineffective, an intra-articular injection was later given. Groin pain, sitting pain, sacroiliac joint shear test results, and posterior superior iliac spine and sacro-tuberous ligament tenderness were also compared between patients for whom a peri- or intra-articular injection was effective. Seventy-two (85%) of 85 patients had an effective injection. Out of these 72 patients, 58 (81%) had a positive peri-articular injection and 14 (19%) had a positive intra-articular injection. Four items, excluding tenderness of the sacro-tuberous ligament had no significant difference between these two injection types. To treat sacroiliac joint-related pain at or around the posterior superior iliac spine, a peri-articular injection should be performed first, and only if it is not effective should an intra-articular injection be administered. Using this strategy, we expect that most patients with sacroiliac joint-related pain will be efficiently diagnosed and treated. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Comment on "constructing quantum games from nonfactorizable joint probabilities".

    PubMed

    Frąckiewicz, Piotr

    2013-09-01

    In the paper [Phys. Rev. E 76, 061122 (2007)], the authors presented a way of playing 2 × 2 games so that players were able to exploit nonfactorizable joint probabilities respecting the nonsignaling principle (i.e., relativistic causality). We are going to prove, however, that the scheme does not generalize the games studied in the commented paper. Moreover, it allows the players to obtain nonclassical results even if the factorizable joint probabilities are used.

  19. Efficient Posterior Probability Mapping Using Savage-Dickey Ratios

    PubMed Central

    Penny, William D.; Ridgway, Gerard R.

    2013-01-01

    Statistical Parametric Mapping (SPM) is the dominant paradigm for mass-univariate analysis of neuroimaging data. More recently, a Bayesian approach termed Posterior Probability Mapping (PPM) has been proposed as an alternative. PPM offers two advantages: (i) inferences can be made about effect size thus lending a precise physiological meaning to activated regions, (ii) regions can be declared inactive. This latter facility is most parsimoniously provided by PPMs based on Bayesian model comparisons. To date these comparisons have been implemented by an Independent Model Optimization (IMO) procedure which separately fits null and alternative models. This paper proposes a more computationally efficient procedure based on Savage-Dickey approximations to the Bayes factor, and Taylor-series approximations to the voxel-wise posterior covariance matrices. Simulations show the accuracy of this Savage-Dickey-Taylor (SDT) method to be comparable to that of IMO. Results on fMRI data show excellent agreement between SDT and IMO for second-level models, and reasonable agreement for first-level models. This Savage-Dickey test is a Bayesian analogue of the classical SPM-F and allows users to implement model comparison in a truly interactive manner. PMID:23533640

  20. Correlation between hindfoot joint three-dimensional kinematics and the changes of the medial arch angle in stage II posterior tibial tendon dysfunction flatfoot.

    PubMed

    Zhang, Yi-Jun; Xu, Jian; Wang, Yue; Lin, Xiang-Jin; Ma, Xin

    2015-02-01

    The aim of this study was to explore the correlation between the kinematics of the hindfoot joint and the medial arch angle change in stage II posterior tibial tendon dysfunction flatfoot three-dimensionally under loading. Computed tomography (CT) scans of 12 healthy feet and 12 feet with stage II posterior tibial tendon dysfunction flatfoot were taken both in non- and full-body-weight-bearing condition. The CT images of the hindfoot bones were reconstructed into three-dimensional models with Mimics and Geomagic reverse engineering software. The three-dimensional changes of the hindfoot joint were calculated to determine their correlation to the medial longitudinal arch angle. The medial arch angle change was larger in stage II posterior tibial tendon dysfunction flatfoot compared to that in healthy foot under loading. The rotation and translation of the talocalcaneal joint, the talonavicular joint and the calcanocuboid joint had little influence on the change of the medial arch angle in healthy foot. However, the eversion of the talocalcaneal joint, the proximal translation of the calcaneus relative to the talus and the dorsiflexion of talonavicular joint could increase the medial arch angle in stage II posterior tibial tendon dysfunction flatfoot under loading. Joint instability occurred in patients with stage II posterior tibial tendon dysfunction flatfoot under loading. Limitation of over movement of the talocalcaneal joint and the talonavicular joint may help correct the medial longitudinal arch in stage II posterior tibial tendon dysfunction flatfoot. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Back to Normal! Gaussianizing posterior distributions for cosmological probes

    NASA Astrophysics Data System (ADS)

    Schuhmann, Robert L.; Joachimi, Benjamin; Peiris, Hiranya V.

    2014-05-01

    We present a method to map multivariate non-Gaussian posterior probability densities into Gaussian ones via nonlinear Box-Cox transformations, and generalizations thereof. This is analogous to the search for normal parameters in the CMB, but can in principle be applied to any probability density that is continuous and unimodal. The search for the optimally Gaussianizing transformation amongst the Box-Cox family is performed via a maximum likelihood formalism. We can judge the quality of the found transformation a posteriori: qualitatively via statistical tests of Gaussianity, and more illustratively by how well it reproduces the credible regions. The method permits an analytical reconstruction of the posterior from a sample, e.g. a Markov chain, and simplifies the subsequent joint analysis with other experiments. Furthermore, it permits the characterization of a non-Gaussian posterior in a compact and efficient way. The expression for the non-Gaussian posterior can be employed to find analytic formulae for the Bayesian evidence, and consequently be used for model comparison.

  2. Bilateral sacroiliac joint dislocation (anterior and posterior) with triradiate cartilage injury: a case report.

    PubMed

    Lee, Dae-Hee; Jeong, Woong-Kyo; Inna, Prashanth; Noh, Won; Lee, Dong-Ki; Lee, Soon-Hyuck

    2011-12-01

    Pediatric sacroiliac joint injuries are uncommon. Significant pelvis ring disruptions in children are rare, and their management is complicated by patient size, differences in bony architecture, and future growth and remodeling potential. We present a rare case of anterior sacroiliac joint dislocation associated with triradiate cartilage injury with a posterior sacroiliac dislocation on the contralateral side. This appears to be the first such case reported in the literature.

  3. An efficient algorithm to compute marginal posterior genotype probabilities for every member of a pedigree with loops

    PubMed Central

    2009-01-01

    Background Marginal posterior genotype probabilities need to be computed for genetic analyses such as geneticcounseling in humans and selective breeding in animal and plant species. Methods In this paper, we describe a peeling based, deterministic, exact algorithm to compute efficiently genotype probabilities for every member of a pedigree with loops without recourse to junction-tree methods from graph theory. The efficiency in computing the likelihood by peeling comes from storing intermediate results in multidimensional tables called cutsets. Computing marginal genotype probabilities for individual i requires recomputing the likelihood for each of the possible genotypes of individual i. This can be done efficiently by storing intermediate results in two types of cutsets called anterior and posterior cutsets and reusing these intermediate results to compute the likelihood. Examples A small example is used to illustrate the theoretical concepts discussed in this paper, and marginal genotype probabilities are computed at a monogenic disease locus for every member in a real cattle pedigree. PMID:19958551

  4. Combined medial displacement calcaneal osteotomy, subtalar joint arthrodesis, and ankle arthrodiastasis for end-stage posterior tibial tendon dysfunction.

    PubMed

    Stapleton, John J; Belczyk, Ronald; Zgonis, Thomas; Polyzois, Vasilios D

    2009-04-01

    Combining an ankle arthrodiastasis with a medial displacement calcaneal osteotomy and a subtalar joint arthrodesis offers surgeons a joint-sparing procedure for young and active patients who have end-stage posterior tibial tendon dysfunction and ankle joint involvement. An isolated subtalar joint arthrodesis or triple arthrodesis combined with an ankle arthrodiastasis is an option that can be used in certain case scenarios. Delaying the need for a joint destructive procedure through an ankle arthrodiastasis, however, may have a great impact in the near future, as advancements are underway to improve the use of ankle endoprosthesis.

  5. The Influence of Joint Distraction Force on the Soft-Tissue Balance Using Modified Gap-Balancing Technique in Posterior-Stabilized Total Knee Arthroplasty.

    PubMed

    Nagai, Kanto; Muratsu, Hirotsugu; Takeoka, Yoshiki; Tsubosaka, Masanori; Kuroda, Ryosuke; Matsumoto, Tomoyuki

    2017-10-01

    During modified gap-balancing technique, there is no consensus on the best method for obtaining appropriate soft-tissue balance and determining the femoral component rotation. Sixty-five varus osteoarthritic patients underwent primary posterior-stabilized total knee arthroplasty using modified gap-balancing technique. The influence of joint distraction force on the soft-tissue balance measurement during the modified gap-balancing technique was evaluated with Offset Repo-Tensor between the osteotomized surfaces at extension, and between femoral posterior condyles and tibial osteotomized surface at flexion of the knee before the resection of femoral posterior condyles. The joint center gap (millimeters) and varus ligament balance (°) were measured under 20, 40, and 60 pounds of joint distraction forces, and the differences in these values at extension and flexion (the value at flexion minus the value at extension) were also calculated. The differences in joint center gap (-6.7, -6.8, and -6.9 mm for 20, 40, and 60 pounds, respectively) and varus ligament balance (3.5°, 3.8°, and 3.8°) at extension and flexion were not significantly different among different joint distraction forces, although the joint center gap and varus ligament balance significantly increased stepwise at extension and flexion as the joint distraction force increased. The difference in joint center gap and varus ligament balance at extension and flexion were consistent even among the different joint distraction forces. This novel index would be useful for the determination of femoral component rotation during the modified gap-balancing technique. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. PARTS: Probabilistic Alignment for RNA joinT Secondary structure prediction

    PubMed Central

    Harmanci, Arif Ozgun; Sharma, Gaurav; Mathews, David H.

    2008-01-01

    A novel method is presented for joint prediction of alignment and common secondary structures of two RNA sequences. The joint consideration of common secondary structures and alignment is accomplished by structural alignment over a search space defined by the newly introduced motif called matched helical regions. The matched helical region formulation generalizes previously employed constraints for structural alignment and thereby better accommodates the structural variability within RNA families. A probabilistic model based on pseudo free energies obtained from precomputed base pairing and alignment probabilities is utilized for scoring structural alignments. Maximum a posteriori (MAP) common secondary structures, sequence alignment and joint posterior probabilities of base pairing are obtained from the model via a dynamic programming algorithm called PARTS. The advantage of the more general structural alignment of PARTS is seen in secondary structure predictions for the RNase P family. For this family, the PARTS MAP predictions of secondary structures and alignment perform significantly better than prior methods that utilize a more restrictive structural alignment model. For the tRNA and 5S rRNA families, the richer structural alignment model of PARTS does not offer a benefit and the method therefore performs comparably with existing alternatives. For all RNA families studied, the posterior probability estimates obtained from PARTS offer an improvement over posterior probability estimates from a single sequence prediction. When considering the base pairings predicted over a threshold value of confidence, the combination of sensitivity and positive predictive value is superior for PARTS than for the single sequence prediction. PARTS source code is available for download under the GNU public license at http://rna.urmc.rochester.edu. PMID:18304945

  7. MR arthrography of the posterior labrocapsular complex: relationship with glenohumeral joint alignment and clinical posterior instability.

    PubMed

    Tung, Glenn A; Hou, David D

    2003-02-01

    The purpose of our study was to investigate the relationship between tears of the posterior labrocapsular complex and glenohumeral alignment on MR arthrography and the presence and extent of posterior labrocapsular tears in patients with posterior instability. Posterior labrocapsular tears identified on 24 MR arthrograms and surgically confirmed were evaluated for length of tear and labrocapsular avulsion. These examinations and a comparison cohort of 70 normal MR arthrograms with normal findings were also evaluated for humeral head position relative to the glenoid fossa. Medical records were reviewed for clinical diagnosis of posterior instability and history of shoulder trauma. The position of the humeral head relative to the glenoid was significantly more posterior in patients with posterior labral tear than in patients with a normal posterior labrum (4.9 mm versus 0.7 mm; p < 0.0001). The mean length (+/- SD) of posterior labral tear was 15.9 +/- 1.7 mm, and a direct correlation was found between tear length and posterior humeral translation (r = -0.65; p = 0.002). Posterior labral tears were significantly longer (18.6 vs 13.1 mm; p = 0.04), and posterior humeral translation was greater (6.4 vs 3.4 mm; p = 0.006) in patients with labrocapsular avulsion than in those without avulsion. Twelve (50%) of the patients with posterior labrocapsular tear had posterior instability, and 10 (83%) had a history of macrotrauma. On MR arthrography, the mean posterior humeral translation was greater (6.2 mm +/- 0.08; p = 0.019), posterior labral tears were longer (19.4 mm +/- 1.7; p = 0.0008), and labrocapsular avulsion was more common (83%; p = 0.0001) in patients with posterior instability than in patients who had a posterior labral tear but a clinically stable shoulder. Clinical posterior instability is associated with excessive posterior humeral translation, long posterior labral tears, and posterior labrocapsular avulsion.

  8. Reweighting Data in the Spirit of Tukey: Using Bayesian Posterior Probabilities as Rasch Residuals for Studying Misfit

    ERIC Educational Resources Information Center

    Dardick, William R.; Mislevy, Robert J.

    2016-01-01

    A new variant of the iterative "data = fit + residual" data-analytical approach described by Mosteller and Tukey is proposed and implemented in the context of item response theory psychometric models. Posterior probabilities from a Bayesian mixture model of a Rasch item response theory model and an unscalable latent class are expressed…

  9. Joint Probability Analysis of Extreme Precipitation and Storm Tide in a Coastal City under Changing Environment

    PubMed Central

    Xu, Kui; Ma, Chao; Lian, Jijian; Bin, Lingling

    2014-01-01

    Catastrophic flooding resulting from extreme meteorological events has occurred more frequently and drawn great attention in recent years in China. In coastal areas, extreme precipitation and storm tide are both inducing factors of flooding and therefore their joint probability would be critical to determine the flooding risk. The impact of storm tide or changing environment on flooding is ignored or underestimated in the design of drainage systems of today in coastal areas in China. This paper investigates the joint probability of extreme precipitation and storm tide and its change using copula-based models in Fuzhou City. The change point at the year of 1984 detected by Mann-Kendall and Pettitt’s tests divides the extreme precipitation series into two subsequences. For each subsequence the probability of the joint behavior of extreme precipitation and storm tide is estimated by the optimal copula. Results show that the joint probability has increased by more than 300% on average after 1984 (α = 0.05). The design joint return period (RP) of extreme precipitation and storm tide is estimated to propose a design standard for future flooding preparedness. For a combination of extreme precipitation and storm tide, the design joint RP has become smaller than before. It implies that flooding would happen more often after 1984, which corresponds with the observation. The study would facilitate understanding the change of flood risk and proposing the adaption measures for coastal areas under a changing environment. PMID:25310006

  10. Joint probability analysis of extreme precipitation and storm tide in a coastal city under changing environment.

    PubMed

    Xu, Kui; Ma, Chao; Lian, Jijian; Bin, Lingling

    2014-01-01

    Catastrophic flooding resulting from extreme meteorological events has occurred more frequently and drawn great attention in recent years in China. In coastal areas, extreme precipitation and storm tide are both inducing factors of flooding and therefore their joint probability would be critical to determine the flooding risk. The impact of storm tide or changing environment on flooding is ignored or underestimated in the design of drainage systems of today in coastal areas in China. This paper investigates the joint probability of extreme precipitation and storm tide and its change using copula-based models in Fuzhou City. The change point at the year of 1984 detected by Mann-Kendall and Pettitt's tests divides the extreme precipitation series into two subsequences. For each subsequence the probability of the joint behavior of extreme precipitation and storm tide is estimated by the optimal copula. Results show that the joint probability has increased by more than 300% on average after 1984 (α = 0.05). The design joint return period (RP) of extreme precipitation and storm tide is estimated to propose a design standard for future flooding preparedness. For a combination of extreme precipitation and storm tide, the design joint RP has become smaller than before. It implies that flooding would happen more often after 1984, which corresponds with the observation. The study would facilitate understanding the change of flood risk and proposing the adaption measures for coastal areas under a changing environment.

  11. Bayesian selection of misspecified models is overconfident and may cause spurious posterior probabilities for phylogenetic trees.

    PubMed

    Yang, Ziheng; Zhu, Tianqi

    2018-02-20

    The Bayesian method is noted to produce spuriously high posterior probabilities for phylogenetic trees in analysis of large datasets, but the precise reasons for this overconfidence are unknown. In general, the performance of Bayesian selection of misspecified models is poorly understood, even though this is of great scientific interest since models are never true in real data analysis. Here we characterize the asymptotic behavior of Bayesian model selection and show that when the competing models are equally wrong, Bayesian model selection exhibits surprising and polarized behaviors in large datasets, supporting one model with full force while rejecting the others. If one model is slightly less wrong than the other, the less wrong model will eventually win when the amount of data increases, but the method may become overconfident before it becomes reliable. We suggest that this extreme behavior may be a major factor for the spuriously high posterior probabilities for evolutionary trees. The philosophical implications of our results to the application of Bayesian model selection to evaluate opposing scientific hypotheses are yet to be explored, as are the behaviors of non-Bayesian methods in similar situations.

  12. Comparison of upper extremity glenohumeral joint forces in children with cerebral palsy using anterior and posterior walkers - biomed 2009.

    PubMed

    Strifling, Kelly M B; Konop, Katherine A; Wang, Mei; Harris, Gerald F

    2009-01-01

    Walkers are prescribed with the notion that one type of walker will be better for a child than another. One underlying justification for this practice is the theory that one walker may produce less stress on the upper extremities as the patient uses the walker. Nevertheless, upper extremity joint loading is not typically analyzed during walker assisted gait in children with spastic diplegic cerebral palsy. It has been difficult to evaluate the theory of walker prescription based on upper extremity stresses because loading on the upper extremities however has not been quantified until recently. In this study, weight bearing on the glenohumeral joints was analyzed in five children with spastic diplegic cerebral palsy using both anterior and posterior walkers fitted with 6-axis handle transducers. Though walkers' effects on the upper extremities proved to be similar between walker types, the differences between the walkers may have some clinical significance in the long run. In general, posterior walker use created larger glenohumeral joint forces. Though these differences are not statistically significant, over time and with repetitive loading they may be clinically significant.

  13. Anatomical significance of a posterior horn of medial meniscus: the relationship between its radial tear and cartilage degradation of joint surface.

    PubMed

    Kan, Akinori; Oshida, Midori; Oshida, Shigemi; Imada, Masato; Nakagawa, Takumi; Okinaga, Shuji

    2010-01-12

    Traumatic injury and surgical meniscectomy of a medial meniscus are known to cause subsequent knee osteoarthritis. However, the difference in the prevalence of osteoarthritis caused by the individual type of the medial meniscal tear has not been elucidated. The aim of this study was to investigate what type of tear is predominantly responsible for the degradation of articular cartilage in the medial compartment of knee joints. Five hundred and forty eight cadaveric knees (290 male and 258 female) were registered in this study. The average age of cadavers at death was 78.8 years old (range: 52-103 years). The knees were macroscopically examined and their medial menisci were classified into four groups according to types of tears: "no tear", "radial tear of posterior horn", "other types of tear" and "worn-out meniscus" groups. The severity of cartilage degradation in their medial compartment of knee joints was evaluated using the international cartilage repair society (ICRS) grading system. We statistically compared the ICRS grades among the groups using Mann-Whitney U test. The knees were assigned into the four groups: 416 "no tear" knees, 51 "radial tear of posterior horn" knees, 71 "other types of tear" knees, and 10 "worn-out meniscus" knees. The knees with substantial meniscal tears showed the severer ICRS grades of cartilage degradation than those without meniscal tears. In addition, the ICRS grades were significantly severer in the "radial tear of posterior horn" group than in the "other types of tear" group, suggesting that the radial tear of posterior horn in the medial meniscus is one of the risk factors for cartilage degradation of joint surface. We have clarified the relationship between the radial tear of posterior horn in the medial meniscus and the severer grade of cartilage degradation. This study indicates that the efforts should be made to restore the anatomical role of the posterior horn in keeping the hoop strain, when patients' physical activity

  14. [Classification and Treatment of Sacroiliac Joint Dislocation].

    PubMed

    Tan, Zhen; Huang, Zhong; Li, Liang; Meng, Wei-Kun; Liu, Lei; Zhang, Hui; Wang, Guang-Lin; Huang, Fu-Guo

    2017-09-01

    To develop a renewed classification and treatment regimen for sacroiliac joint dislocation. According to the direction of dislocation of sacroiliac joint,combined iliac,sacral fractures,and fracture morphology,sacroiliac joint dislocation was classified into 4 types. Type Ⅰ (sacroiliac anterior dislocation): main fracture fragments of posterior iliac wing dislocated in front of sacroiliac joint. Type Ⅱ (sacroiliac posterior dislocation): main fracture fragments of posterior iliac wing dislocated in posterior of sacroiliac joint. Type Ⅲ (Crescent fracturedislocation of the sacroiliac joint): upward dislocation of posterior iliac wing with oblique fracture through posterior iliac wing. Type ⅢA: a large crescent fragment and dislocation comprises no more than onethird of sacroiliac joint,which is typically inferior. Type ⅢB: intermediatesize crescent fragment and dislocation comprises between one and twothirds of joint. Type ⅢC: a small crescent fragment where dislocation comprises most,but not the entire joint. Different treatment regimens were selected for different types of fractures. Treatment for type Ⅰ sacroiliac joint dislocation: anterior iliac fossa approach pry stripping reset; sacroiliac joint fixed with sacroiliac screw through percutaneous. Treatment for type Ⅱ sacroiliac joint dislocation: posterior sacroiliac joint posterior approach; sacroiliac joint fixed with sacroiliac screw under computer guidance. Treatment for type ⅢA and ⅢB sacroiliac joint dislocation: posterior sacroiliac joint approach; sacroiliac joint fixed with reconstruction plate. Treatment for type ⅢC sacroiliac joint dislocation: sacroiliac joint closed reduction; sacroiliac joint fixed with sacroiliac screw through percutaneous. Treatment for type Ⅳ sacroiliac joint dislocation: posterior approach; sacroiliac joint fixed with spinal pelvic fixation. Results of 24 to 72 months patient follow-up (mean 34.5 months): 100% survival,100% wound healing,and 100

  15. Joint search and sensor management for geosynchronous satellites

    NASA Astrophysics Data System (ADS)

    Zatezalo, A.; El-Fallah, A.; Mahler, R.; Mehra, R. K.; Pham, K.

    2008-04-01

    Joint search and sensor management for space situational awareness presents daunting scientific and practical challenges as it requires a simultaneous search for new, and the catalog update of the current space objects. We demonstrate a new approach to joint search and sensor management by utilizing the Posterior Expected Number of Targets (PENT) as the objective function, an observation model for a space-based EO/IR sensor, and a Probability Hypothesis Density Particle Filter (PHD-PF) tracker. Simulation and results using actual Geosynchronous Satellites are presented.

  16. Association Between Missing Posterior Teeth and Occurrence of Temporomandibular Joint Condylar Erosion: A Cone Beam Computed Tomography Study.

    PubMed

    Bertram, Felix; Hupp, Linus; Schnabl, Dagmar; Rudisch, Ansgar; Emshoff, Rüdiger

    To determine a possible association between asymptomatic temporomandibular joint (TMJ) condylar erosion and the number of missing posterior teeth and their location, as well as the number of dental quadrants with missing posterior teeth. This case-control study involved 210 patients (male to female ratio = 98:112) aged 16-74 years, with 105 asymptomatic patients with TMJ condylar erosion and a control group of 105 patients without TMJ condylar erosion. Cone beam computed tomography images were evaluated to classify the severity of TMJ condylar erosion as grade 0 (absence of erosion), grade I (slight erosion), grade II (moderate erosion), or grade III (extensive erosion). The number of missing posterior teeth (mean ± standard deviation [SD]; 2.7 ± 2.4 vs 0.7 ± 1.2) (P < .001), number of dental quadrants with missing posterior teeth (1.5 ± 1.3 vs 0.6 ± 0.9) (P < .001), and bilateral location of missing posterior teeth (41 ± 39.0 vs 10 ± 9.5) (P < .001) were all significantly higher in patients with erosion than in those without erosion. The condylar erosion grade was significantly associated with the number of missing posterior teeth (odds ratio [OR] = 1.24; P = .006), the number of dental quadrants with missing posterior teeth (OR = 1.36; P = .006), and the bilateral occurrence of missing posterior teeth (OR = 3.03; P = .002). The findings from this study suggest a possible association between TMJ condylar erosion grades and the number of missing posterior teeth, the number of quadrants with missing posterior teeth, and the bilateral occurrence of missing posterior teeth.

  17. Topographical relations between the posterior cricothyroid ligament and the inferior laryngeal nerve.

    PubMed

    Reidenbach, M M

    1995-01-01

    The posterior cricothyroid ligament and its topographic relation to the inferior laryngeal nerve were studied in 54 human adult male and female larynges. Fourteen specimens were impregnated with curable polymers and cut into 600-800 microns sections along different planes. Forty formalin-fixed hemi-larynges were dissected and various measurements were made. The posterior cricothyroid ligament provides a dorsal strengthening for the joint capsule of the cricothyroid joint. Its fibers spread in a fan-like manner from a small area of origin at the cricoid cartilage to a more extended area of attachment at the inferior thyroid cornu. The ligament consists of one (7.5%) to four (12.5%), in most cases of three (45.0%) or two (35.0%), individual parts oriented from mediocranial to latero-caudal. The inferior laryngeal nerve courses immediately dorsal to the ligament. In 60% it is covered by fibers of the posterior cricoarytenoid muscle, in the remaining 40% it is not. In this latter topographic situation there is almost no soft tissue interposed between the nerve and the hypopharynx. Therefore, the nerve may be exposed to pressure forces exerted from dorsally. It may be pushed against the unyielding posterior cricothyroid ligament and suffer functional or structural impairment. Probably, this mechanism may explain some of the laryngeal nerve lesions described in the literature after insertion of gastric tubes.

  18. Factors related to the joint probability of flooding on paired streams

    USGS Publications Warehouse

    Koltun, G.F.; Sherwood, J.M.

    1998-01-01

    The factors related to the joint probabilty of flooding on paired streams were investigated and quantified to provide information to aid in the design of hydraulic structures where the joint probabilty of flooding is an element of the design criteria. Stream pairs were considered to have flooded jointly at the design-year flood threshold (corresponding to the 2-, 10-, 25-, or 50-year instantaneous peak streamflow) if peak streamflows at both streams in the pair were observed or predicted to have equaled or exceeded the threshold on a given calendar day. Daily mean streamflow data were used as a substitute for instantaneous peak streamflow data to determine which flood thresholds were equaled or exceeded on any given day. Instantaneous peak streamflow data, when available, were used preferentially to assess flood-threshold exceedance. Daily mean streamflow data for each stream were paired with concurrent daily mean streamflow data at the other streams. Observed probabilities of joint flooding, determined for the 2-, 10-, 25-, and 50-year flood thresholds, were computed as the ratios of the total number of days when streamflows at both streams concurrently equaled or exceeded their flood thresholds (events) to the total number of days where streamflows at either stream equaled or exceeded its flood threshold (trials). A combination of correlation analyses, graphical analyses, and logistic-regression analyses were used to identify and quantify factors associated with the observed probabilities of joint flooding (event-trial ratios). The analyses indicated that the distance between drainage area centroids, the ratio of the smaller to larger drainage area, the mean drainage area, and the centroid angle adjusted 30 degrees were the basin characteristics most closely associated with the joint probabilty of flooding on paired streams in Ohio. In general, the analyses indicated that the joint probabilty of flooding decreases with an increase in centroid distance and

  19. Posterior Tibial Slope Angle Correlates With Peak Sagittal and Frontal Plane Knee Joint Loading During Robotic Simulations of Athletic Tasks.

    PubMed

    Bates, Nathaniel A; Nesbitt, Rebecca J; Shearn, Jason T; Myer, Gregory D; Hewett, Timothy E

    2016-07-01

    Tibial slope angle is a nonmodifiable risk factor for anterior cruciate ligament (ACL) injury. However, the mechanical role of varying tibial slopes during athletic tasks has yet to be clinically quantified. To examine the influence of posterior tibial slope on knee joint loading during controlled, in vitro simulation of the knee joint articulations during athletic tasks. Descriptive laboratory study. A 6 degree of freedom robotic manipulator positionally maneuvered cadaveric knee joints from 12 unique specimens with varying tibial slopes (range, -7.7° to 7.7°) through drop vertical jump and sidestep cutting tasks that were derived from 3-dimensional in vivo motion recordings. Internal knee joint torques and forces were recorded throughout simulation and were linearly correlated with tibial slope. The mean (±SD) posterior tibial slope angle was 2.2° ± 4.3° in the lateral compartment and 2.3° ± 3.3° in the medial compartment. For simulated drop vertical jumps, lateral compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee adduction (r = 0.60-0.65), flexion (r = 0.64-0.66), lateral (r = 0.57-0.69), and external rotation torques (r = 0.47-0.72) as well as inverse correlations with peak abduction (r = -0.42 to -0.61) and internal rotation torques (r = -0.39 to -0.79). Only frontal plane torques were correlated during sidestep cutting simulations. For simulated drop vertical jumps, medial compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee flexion torque (r = 0.64-0.69) and lateral knee force (r = 0.55-0.74) as well as inverse correlations with peak external torque (r = -0.34 to -0.67) and medial knee force (r = -0.58 to -0.59). These moderate correlations were also present during simulated sidestep cutting. The investigation supported the theory that increased posterior tibial slope would lead to greater magnitude knee joint moments, specifically

  20. The return period analysis of natural disasters with statistical modeling of bivariate joint probability distribution.

    PubMed

    Li, Ning; Liu, Xueqin; Xie, Wei; Wu, Jidong; Zhang, Peng

    2013-01-01

    New features of natural disasters have been observed over the last several years. The factors that influence the disasters' formation mechanisms, regularity of occurrence and main characteristics have been revealed to be more complicated and diverse in nature than previously thought. As the uncertainty involved increases, the variables need to be examined further. This article discusses the importance and the shortage of multivariate analysis of natural disasters and presents a method to estimate the joint probability of the return periods and perform a risk analysis. Severe dust storms from 1990 to 2008 in Inner Mongolia were used as a case study to test this new methodology, as they are normal and recurring climatic phenomena on Earth. Based on the 79 investigated events and according to the dust storm definition with bivariate, the joint probability distribution of severe dust storms was established using the observed data of maximum wind speed and duration. The joint return periods of severe dust storms were calculated, and the relevant risk was analyzed according to the joint probability. The copula function is able to simulate severe dust storm disasters accurately. The joint return periods generated are closer to those observed in reality than the univariate return periods and thus have more value in severe dust storm disaster mitigation, strategy making, program design, and improvement of risk management. This research may prove useful in risk-based decision making. The exploration of multivariate analysis methods can also lay the foundation for further applications in natural disaster risk analysis. © 2012 Society for Risk Analysis.

  1. [Effect of posterior cruciate ligament retaining or not on knee-joint proprioception].

    PubMed

    Wu, Yansheng; Li, Yongsheng; Chen, Baicheng

    2013-07-01

    To analyze the effect of the posterior cruciate ligament (PCL) retaining or not on knee-joint proprioception by comparing the proprioceptive difference between PCL retaining and no PCL retaining in total knee arthroplasty (TKA). Between June 2009 and June 2010, 38 osteoarthritis patients meeting the inclusion criteria were divided into PCL retaining group (group A, n=19) and PCL-substituting group (group B, n=19) according to the random number table. There was no significant difference in gender, age, disease duration, the range of motion of the knee between 2 groups (P > 0.05). The effectiveness and the knee-joint proprioception were separately assessed by the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score and the passive angle reproduction test (30, 60, and 90 degrees of knee flexion) preoperatively and 12 months postoperatively. All incisons healed by first intention, without complications of infection, fracture, and deep vein thrombosis of lower limb. The patients were followed up 12-17 months (mean, 14.1 months). The knee function after operation was obviously improved when compared with preoperative one; significant differences were observed in the WOMAC scores and the results of passive angle reproduction test between at preoperation and at 12 months after operation (P < 0.05), but no significant difference was found between group A and group B (P > 0.05). Whether PCL retaining or not in TKA both can improve knee-joint proprioception, and no obvious difference between them.

  2. Posterior labral injury in contact athletes.

    PubMed

    Mair, S D; Zarzour, R H; Speer, K P

    1998-01-01

    Nine athletes (seven football offensive linemen, one defensive lineman, and one lacrosse player) were found at arthroscopy to have posterior labral detachment from the glenoid. In our series, this lesion is specific to contact athletes who engage their opponents with arms in front of the body. All patients had pain with bench pressing and while participating in their sport, diminishing their ability to play effectively. Conservative measures were ineffective in relieving their symptoms. Examination under anesthesia revealed symmetric glenohumeral translation bilaterally, without evidence of posterior instability. Treatment consisted of glenoid rim abradement and posterior labral repair with a bioabsorbable tack. All patients returned to complete at least one full season of contact sports and weightlifting without pain (minimum follow-up, > or = 2 years). Although many injuries leading to subluxation of the glenohumeral joint occur when an unanticipated force is applied, contact athletes ready their shoulder muscles in anticipation of impact with opponents. This leads to a compressive force at the glenohumeral joint. We hypothesize that, in combination with a posteriorly directed force at impact, the resultant vector is a shearing force to the posterior labrum and articular surface. Repeated exposure leads to posterior labral detachment without capsular injury. Posterior labral reattachment provides consistently good results, allowing the athlete to return to competition.

  3. Effects of footwear on lead limb knee and ankle joint kinematics in a fast bowler with a history of posterior ankle joint impingement-a case report.

    PubMed

    Bishop, Chris; Bartold, Simon; Thewlis, Dominic

    2013-11-01

    This case study reports the kinematic effect of 2 different cricket shoes on a fast bowler who reports a history of posterior ankle joint impingement. The participant bowled 6 trials in 2 pairs of cricket shoes. The 3-dimensional kinematics of the joints of the front leg was quantified during stance phase of the delivery stride. Wearing the high-cut shoe resulted in the ankle being 7.7-degree angle more plantarflexed at initial contact compared with the low-cut shoe. Again, when wearing the high-cut shoe compared with the low-cut shoe, the ankle joint was 15.5-degree angle more adducted and the knee was 4.1-degree angle less externally rotated at initial contact. This case study identifies the bowler's preferred shoe (high-cut shoe) as a potential contributing factor to the symptoms he was experiencing.

  4. The effect of posterior tibial slope on knee flexion in posterior-stabilized total knee arthroplasty.

    PubMed

    Shi, Xiaojun; Shen, Bin; Kang, Pengde; Yang, Jing; Zhou, Zongke; Pei, Fuxing

    2013-12-01

    To evaluate and quantify the effect of the tibial slope on the postoperative maximal knee flexion and stability in the posterior-stabilized total knee arthroplasty (TKA). Fifty-six patients (65 knees) who had undergone TKA with the posterior-stabilized prostheses were divided into the following 3 groups according to the measured tibial slopes: Group 1: ≤4°, Group 2: 4°-7° and Group 3: >7°. The preoperative range of the motion, the change in the posterior condylar offset, the elevation of the joint line, the postoperative tibiofemoral angle and the preoperative and postoperative Hospital for Special Surgery (HSS) scores were recorded. The tibial anteroposterior translation was measured using the Kneelax 3 Arthrometer at both the 30° and the 90° flexion angles. The mean values of the postoperative maximal knee flexion were 101° (SD 5), 106° (SD 5) and 113° (SD 9) in Groups 1, 2 and 3, respectively. A significant difference was found in the postoperative maximal flexion between the 3 groups (P < 0.001). However, no significant differences were found between the 3 groups in the postoperative HSS scores, the changes in the posterior condylar offset, the elevation of the joint line or the tibial anteroposterior translation at either the 30° or the 90° flexion angles. A 1° increase in the tibial slope resulted in a 1.8° flexion increment (r = 1.8, R (2) = 0.463, P < 0.001). An increase in the posterior tibial slope can significantly increase the postoperative maximal knee flexion. The tibial slope with an appropriate flexion and extension gap balance during the operation does not affect the joint stability.

  5. On the use of posterior predictive probabilities and prediction uncertainty to tailor informative sampling for parasitological surveillance in livestock.

    PubMed

    Musella, Vincenzo; Rinaldi, Laura; Lagazio, Corrado; Cringoli, Giuseppe; Biggeri, Annibale; Catelan, Dolores

    2014-09-15

    Model-based geostatistics and Bayesian approaches are appropriate in the context of Veterinary Epidemiology when point data have been collected by valid study designs. The aim is to predict a continuous infection risk surface. Little work has been done on the use of predictive infection probabilities at farm unit level. In this paper we show how to use predictive infection probability and related uncertainty from a Bayesian kriging model to draw a informative samples from the 8794 geo-referenced sheep farms of the Campania region (southern Italy). Parasitological data come from a first cross-sectional survey carried out to study the spatial distribution of selected helminths in sheep farms. A grid sampling was performed to select the farms for coprological examinations. Faecal samples were collected for 121 sheep farms and the presence of 21 different helminths were investigated using the FLOTAC technique. The 21 responses are very different in terms of geographical distribution and prevalence of infection. The observed prevalence range is from 0.83% to 96.69%. The distributions of the posterior predictive probabilities for all the 21 parasites are very heterogeneous. We show how the results of the Bayesian kriging model can be used to plan a second wave survey. Several alternatives can be chosen depending on the purposes of the second survey: weight by posterior predictive probabilities, their uncertainty or combining both information. The proposed Bayesian kriging model is simple, and the proposed samping strategy represents a useful tool to address targeted infection control treatments and surbveillance campaigns. It is easily extendable to other fields of research. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Idealized models of the joint probability distribution of wind speeds

    NASA Astrophysics Data System (ADS)

    Monahan, Adam H.

    2018-05-01

    The joint probability distribution of wind speeds at two separate locations in space or points in time completely characterizes the statistical dependence of these two quantities, providing more information than linear measures such as correlation. In this study, we consider two models of the joint distribution of wind speeds obtained from idealized models of the dependence structure of the horizontal wind velocity components. The bivariate Rice distribution follows from assuming that the wind components have Gaussian and isotropic fluctuations. The bivariate Weibull distribution arises from power law transformations of wind speeds corresponding to vector components with Gaussian, isotropic, mean-zero variability. Maximum likelihood estimates of these distributions are compared using wind speed data from the mid-troposphere, from different altitudes at the Cabauw tower in the Netherlands, and from scatterometer observations over the sea surface. While the bivariate Rice distribution is more flexible and can represent a broader class of dependence structures, the bivariate Weibull distribution is mathematically simpler and may be more convenient in many applications. The complexity of the mathematical expressions obtained for the joint distributions suggests that the development of explicit functional forms for multivariate speed distributions from distributions of the components will not be practical for more complicated dependence structure or more than two speed variables.

  7. Fluoroscopic Sacroiliac Joint Injection: Is Oblique Angulation Really Necessary?

    PubMed

    Khuba, Sandeep; Agarwal, Anil; Gautam, Sujeet; Kumar, Sanjay

    2016-01-01

    The conventional technique for sacroiliac (SI) joint injection involves aligning the anterior and posterior aspects of the SI joint under fluoroscopic guidance and then entering the SI joint in the most caudal aspect. We wish to highlight that there is no added advantage to aligning both the anterior and posterior joint lines of the SI joint as it is time consuming, associated with additional radiation exposure, and may make the entry into the posterior SI joint technically more difficult. Observational study. Pain Clinic, Department of Anesthesiology. With the patient lying prone on fluoroscopy table, SI joint injection is performed with a 22 G, 10 cm spinal needle in a true anteroposterior (AP) view, where anterior and posterior SI joint spaces are seen as separate entities, where the medial joint space represents the posterior SI joint and the lateral joint space represents the anterior SI joint. The distal 1 cm of the medial joint space is entered under AP view. If the SI joint is seen as a straight line rather than 2 joint spaces in the AP view then the image intensifier of the fluoroscope was tilted cranially to elongate the image of the lower part of the posterior SI joint, thus facilitating entry into this part of the joint which was confirmed by administering 0.3 to 0.5 mL of radiopaque contrast medium. Sixty SI joints of 58 patients were injected under an AP fluoroscopic view. Forty-two (70%) SI joints were seen as 2 separate medial and lateral joint spaces and were entered in distal 1 cm of the medial joint space. In 18 (30%) joints seen as a straight line rather than 2 separate spaces, the image intensifier of the fluoroscope was tilted cranially to elongate the image of the lower part of the posterior SI joint and then the SI joint was entered in its distal 1 cm. Confirmation of entry into the SI joint was confirmed by with 0.3 to 0.5 mL of radiopaque contrast medium. In 4 cases the joints did not show the correct radiopaque contrast spread (3/42 and 1

  8. Differences in knee joint kinematics and forces after posterior cruciate retaining and stabilized total knee arthroplasty.

    PubMed

    Wünschel, Markus; Leasure, Jeremi M; Dalheimer, Philipp; Kraft, Nicole; Wülker, Nikolaus; Müller, Otto

    2013-12-01

    Posterior cruciate ligament (PCL) retaining (CR) and -sacrificing (PS) total knee arthroplasties (TKA) are widely-used to treat osteoarthritis of the knee joint. The PS design substitutes the function of the PCL with a cam-spine mechanism which may produce adverse changes to joint kinematics and kinetics. CR- and PS-TKA were performed on 11 human knee specimens. Joint kinematics were measured with a dynamic knee simulator and motion tracking equipment. In-situ loads of the PCL and cam-spine were measured with a robotic force sensor system. Partial weight bearing flexions were simulated and external forces were applied. The PS-TKA rotated significantly less throughout the whole flexion range compared to the CR-TKA. Femoral roll back was greater in the PS-TKA; however, this was not correlated with lower quadriceps forces. Application of external loads produced significantly different in-situ force profiles between the TKA systems. Our data demonstrate that the PS-design significantly alters kinematics of the knee joint. Our data also suggest the cam-spine mechanism may have little influence on high flexion kinematics (such as femoral rollback) with most of the load burden shared by supporting implant and soft-tissue structures. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Exact joint density-current probability function for the asymmetric exclusion process.

    PubMed

    Depken, Martin; Stinchcombe, Robin

    2004-07-23

    We study the asymmetric simple exclusion process with open boundaries and derive the exact form of the joint probability function for the occupation number and the current through the system. We further consider the thermodynamic limit, showing that the resulting distribution is non-Gaussian and that the density fluctuations have a discontinuity at the continuous phase transition, while the current fluctuations are continuous. The derivations are performed by using the standard operator algebraic approach and by the introduction of new operators satisfying a modified version of the original algebra. Copyright 2004 The American Physical Society

  10. Medial meniscus posterior horn avulsion.

    PubMed

    Marzo, John M

    2009-05-01

    Avulsion of the posterior horn of the medial meniscus can occur from acute trauma or chronic degeneration, leading to meniscus extrusion, articular cartilage loss, osteophyte formation, and medial joint space narrowing. With meniscus extrusion, the meniscus is unable to resist hoop stresses and cannot shield the adjacent articular cartilage from excessive axial load. Over time, this can lead to symptomatic knee osteoarthritis. Patients typically report pain, swelling, mechanical symptoms, and general functional loss. Although nonsurgical care may relieve symptoms, it is unlikely to alter either the natural history of meniscal loss or the fate of the medial compartment. Surgical repair of posterior horn meniscal avulsion is done in an attempt to restore the anatomy and biomechanical function of the meniscus, and to slow or prevent degenerative joint disease. Meniscal transplantation is reserved for salvage situations.

  11. Joint coverage probability in a simulation study on Continuous-Time Markov Chain parameter estimation.

    PubMed

    Benoit, Julia S; Chan, Wenyaw; Doody, Rachelle S

    2015-01-01

    Parameter dependency within data sets in simulation studies is common, especially in models such as Continuous-Time Markov Chains (CTMC). Additionally, the literature lacks a comprehensive examination of estimation performance for the likelihood-based general multi-state CTMC. Among studies attempting to assess the estimation, none have accounted for dependency among parameter estimates. The purpose of this research is twofold: 1) to develop a multivariate approach for assessing accuracy and precision for simulation studies 2) to add to the literature a comprehensive examination of the estimation of a general 3-state CTMC model. Simulation studies are conducted to analyze longitudinal data with a trinomial outcome using a CTMC with and without covariates. Measures of performance including bias, component-wise coverage probabilities, and joint coverage probabilities are calculated. An application is presented using Alzheimer's disease caregiver stress levels. Comparisons of joint and component-wise parameter estimates yield conflicting inferential results in simulations from models with and without covariates. In conclusion, caution should be taken when conducting simulation studies aiming to assess performance and choice of inference should properly reflect the purpose of the simulation.

  12. Optimal Power Allocation Strategy in a Joint Bistatic Radar and Communication System Based on Low Probability of Intercept

    PubMed Central

    Wang, Fei; Salous, Sana; Zhou, Jianjiang

    2017-01-01

    In this paper, we investigate a low probability of intercept (LPI)-based optimal power allocation strategy for a joint bistatic radar and communication system, which is composed of a dedicated transmitter, a radar receiver, and a communication receiver. The joint system is capable of fulfilling the requirements of both radar and communications simultaneously. First, assuming that the signal-to-noise ratio (SNR) corresponding to the target surveillance path is much weaker than that corresponding to the line of sight path at radar receiver, the analytically closed-form expression for the probability of false alarm is calculated, whereas the closed-form expression for the probability of detection is not analytically tractable and is approximated due to the fact that the received signals are not zero-mean Gaussian under target presence hypothesis. Then, an LPI-based optimal power allocation strategy is presented to minimize the total transmission power for information signal and radar waveform, which is constrained by a specified information rate for the communication receiver and the desired probabilities of detection and false alarm for the radar receiver. The well-known bisection search method is employed to solve the resulting constrained optimization problem. Finally, numerical simulations are provided to reveal the effects of several system parameters on the power allocation results. It is also demonstrated that the LPI performance of the joint bistatic radar and communication system can be markedly improved by utilizing the proposed scheme. PMID:29186850

  13. Optimal Power Allocation Strategy in a Joint Bistatic Radar and Communication System Based on Low Probability of Intercept.

    PubMed

    Shi, Chenguang; Wang, Fei; Salous, Sana; Zhou, Jianjiang

    2017-11-25

    In this paper, we investigate a low probability of intercept (LPI)-based optimal power allocation strategy for a joint bistatic radar and communication system, which is composed of a dedicated transmitter, a radar receiver, and a communication receiver. The joint system is capable of fulfilling the requirements of both radar and communications simultaneously. First, assuming that the signal-to-noise ratio (SNR) corresponding to the target surveillance path is much weaker than that corresponding to the line of sight path at radar receiver, the analytically closed-form expression for the probability of false alarm is calculated, whereas the closed-form expression for the probability of detection is not analytically tractable and is approximated due to the fact that the received signals are not zero-mean Gaussian under target presence hypothesis. Then, an LPI-based optimal power allocation strategy is presented to minimize the total transmission power for information signal and radar waveform, which is constrained by a specified information rate for the communication receiver and the desired probabilities of detection and false alarm for the radar receiver. The well-known bisection search method is employed to solve the resulting constrained optimization problem. Finally, numerical simulations are provided to reveal the effects of several system parameters on the power allocation results. It is also demonstrated that the LPI performance of the joint bistatic radar and communication system can be markedly improved by utilizing the proposed scheme.

  14. Simultaneous avulsion fracture of the posterior medial and posterior lateral meniscus root: a case report and review of the literature.

    PubMed

    Feucht, Matthias J; Salzmann, Gian M; Pestka, Jan M; Südkamp, Norbert P; Niemeyer, Philipp

    2014-04-01

    Injuries of the meniscus roots are increasingly recognized as a serious knee joint pathology. An avulsion fracture of the meniscus root is a rare variant of this injury pattern. In this article, a case of a traumatic simultaneous avulsion fracture of both the posterior medial and posterior lateral meniscus root associated with a tear of the anterior cruciate ligament is presented. Both avulsion fractures were treated by indirect arthroscopic transtibial pullout fixation of the bony fragment. Based on the findings of our literature review, root avulsion fractures seem to be more common in young male patients after an acute trauma to the knee joint.

  15. Influence of fragment size and postoperative joint congruency on long-term outcome of posterior malleolar fractures.

    PubMed

    Drijfhout van Hooff, Cornelis Christiaan; Verhage, Samuel Marinus; Hoogendoorn, Jochem Maarten

    2015-06-01

    One of the factors contributing to long-term outcome of posterior malleolar fractures is the development of osteoarthritis. Based on biomechanical, cadaveric, and small population studies, fixation of posterior malleolar fracture fragments (PMFFs) is usually performed when fragment size exceeds 25-33%. However, the influence of fragment size on long-term clinical and radiological outcome size remains unclear. A retrospective cohort study of 131 patients treated for an isolated ankle fracture with involvement of the posterior malleolus was performed. Mean follow-up was 6.9 (range, 2.5-15.9) years. Patients were divided into groups depending on size of the fragment, small (<5%, n = 20), medium (5-25%, n = 86), or large (>25%, n = 25), and presence of step-off after operative treatment. We have compared functional outcome measures (AOFAS, AAOS), pain (VAS), and dorsiflexion restriction compared to the contralateral ankle and the incidence of osteoarthritis on X-ray. There were no nonunions, 56% of patients had no radiographic osteoarthritis, VAS was 10 of 100, and median clinical score was 90 of 100. More osteoarthritis occurred in ankle fractures with medium and large PMFFs compared to small fragments (small 16%, medium 48%, large 54%; P = .006). Also when comparing small with medium-sized fragments (P = .02), larger fragment size did not lead to a significantly decreased function (median AOFAS 95 vs 88, P = .16). If the PMFF size was >5%, osteoarthritis occurred more frequently when there was a postoperative step-off ≥1 mm in the tibiotalar joint surface (41% vs 61%, P = .02) (whether the posterior fragment had been fixed or not). In this group, fixing the PMFF did not influence development of osteoarthritis. However, in 42% of the cases with fixation of the fragment a postoperative step-off remained (vs 45% in the group without fixation). Osteoarthritis is 1 component of long-term outcome of malleolar fractures, and the results of this study demonstrate that

  16. Measurement of Posterior Tibial Slope Using Magnetic Resonance Imaging.

    PubMed

    Karimi, Elham; Norouzian, Mohsen; Birjandinejad, Ali; Zandi, Reza; Makhmalbaf, Hadi

    2017-11-01

    Posterior tibial slope (PTS) is an important factor in the knee joint biomechanics and one of the bone features, which affects knee joint stability. Posterior tibial slope has impact on flexion gap, knee joint stability and posterior femoral rollback that are related to wide range of knee motion. During high tibial osteotomy and total knee arthroplasty (TKA) surgery, proper retaining the mechanical and anatomical axis is important. The aim of this study was to evaluate the value of posterior tibial slope in medial and lateral compartments of tibial plateau and to assess the relationship among the slope with age, gender and other variables of tibial plateau surface. This descriptive study was conducted on 132 healthy knees (80 males and 52 females) with a mean age of 38.26±11.45 (20-60 years) at Imam Reza hospital in Mashhad, Iran. All patients, selected and enrolled for MRI in this study, were admitted for knee pain with uncertain clinical history. According to initial physical knee examinations the study subjects were reported healthy. The mean posterior tibial slope was 7.78± 2.48 degrees in the medial compartment and 6.85± 2.24 degrees in lateral compartment. No significant correlation was found between age and gender with posterior tibial slope ( P ≥0.05), but there was significant relationship among PTS with mediolateral width, plateau area and medial plateau. Comparison of different studies revealed that the PTS value in our study is different from other communities, which can be associated with genetic and racial factors. The results of our study are useful to PTS reconstruction in surgeries.

  17. A three-step Maximum-A-Posterior probability method for InSAR data inversion of coseismic rupture with application to four recent large earthquakes in Asia

    NASA Astrophysics Data System (ADS)

    Sun, J.; Shen, Z.; Burgmann, R.; Liang, F.

    2012-12-01

    We develop a three-step Maximum-A-Posterior probability (MAP) method for coseismic rupture inversion, which aims at maximizing the a posterior probability density function (PDF) of elastic solutions of earthquake rupture. The method originates from the Fully Bayesian Inversion (FBI) and the Mixed linear-nonlinear Bayesian inversion (MBI) methods , shares the same a posterior PDF with them and keeps most of their merits, while overcoming its convergence difficulty when large numbers of low quality data are used and improving the convergence rate greatly using optimization procedures. A highly efficient global optimization algorithm, Adaptive Simulated Annealing (ASA), is used to search for the maximum posterior probability in the first step. The non-slip parameters are determined by the global optimization method, and the slip parameters are inverted for using the least squares method without positivity constraint initially, and then damped to physically reasonable range. This step MAP inversion brings the inversion close to 'true' solution quickly and jumps over local maximum regions in high-dimensional parameter space. The second step inversion approaches the 'true' solution further with positivity constraints subsequently applied on slip parameters using the Monte Carlo Inversion (MCI) technique, with all parameters obtained from step one as the initial solution. Then the slip artifacts are eliminated from slip models in the third step MAP inversion with fault geometry parameters fixed. We first used a designed model with 45 degree dipping angle and oblique slip, and corresponding synthetic InSAR data sets to validate the efficiency and accuracy of method. We then applied the method on four recent large earthquakes in Asia, namely the 2010 Yushu, China earthquake, the 2011 Burma earthquake, the 2011 New Zealand earthquake and the 2008 Qinghai, China earthquake, and compared our results with those results from other groups. Our results show the effectiveness of

  18. Impact of Posterior Wear on Muscle Length with Reverse Shoulder Arthroplasty.

    PubMed

    Roche, Christopher P; Diep, Phong; Hamilton, Matthew A; Wright, Thomas W; Flurin, Pierre-Henri; Zuckerman, Joseph D; Routman, Howard D

    2015-12-01

    The use of reverse total shoulder arthroplasty (rTSA) in patients with posterior glenoid wear can be challenging. Implanting a baseplate in the correct version may require significant eccentric reaming, which further medializes the joint line and results in greater rotator cuff muscle shortening. To restore the joint line, bone graft may be required, though it is associated with additional risks. As an alternative solution, augmented glenoid baseplates offer the potential to restore the joint line and improve rotator cuff muscle tensioning without the need for eccentric reaming or supplemental bone graft. To that end, this computer analysis quantifies the rotator cuff muscle length for standard and augmented rTSA when used in a normal and posteriorly worn glenoid. These results demonstrate that shortening of the rotator cuff occurred for both the standard and posterior augmented reverse shoulder designs with additional muscle shortening occurring in scapula with posteriorly worn glenoids. More anatomic rotator cuff muscle tensioning was observed with augmented glenoid baseplates. The use of posterior augmented glenoid baseplates has the potential to improve stability and better restore active internal and external rotation, a current limitation of rTSA. However, clinical follow-up is necessary to confirm these favorable biomechanical results.

  19. Modified fluoroscopy-guided sacroiliac joint injection: a technical report.

    PubMed

    Liliang, Po-Chou; Liang, Cheng-Loong; Lu, Kang; Weng, Hui-Ching; Syu, Fei-Kai

    2014-09-01

    Sacroiliac joint (SIJ) injection can occasionally be challenging. We describe our experience in using conventional technique, and we developed an adjustment to overcome difficulties incurred. Conventional technique required superimposition of the posterior and anterior SIJ lines. If this technique failed to provide entry into the joint, fluoroscopy was slightly adjusted to obtain an oblique view. Of 50 SIJ injections, 29 (58%; 44-72%) were successfully performed using conventional technique. In another 21 procedures, 18 (85.7%; 64-99%) were subsequently completed using oblique view technique. The medial joint line, viewed from this angle, corresponded to the posterior joint line in 17 cases. The lateral joint line corresponded to the posterior joint line in one case. Oblique view technique can improve the success rate of SIJ injection. Wiley Periodicals, Inc.

  20. High-resolution urban flood modelling - a joint probability approach

    NASA Astrophysics Data System (ADS)

    Hartnett, Michael; Olbert, Agnieszka; Nash, Stephen

    2017-04-01

    (Divoky et al., 2005). Nevertheless, such events occur and in Ireland alone there are several cases of serious damage due to flooding resulting from a combination of high sea water levels and river flows driven by the same meteorological conditions (e.g. Olbert et al. 2015). A November 2009 fluvial-coastal flooding of Cork City bringing €100m loss was one such incident. This event was used by Olbert et al. (2015) to determine processes controlling urban flooding and is further explored in this study to elaborate on coastal and fluvial flood mechanisms and their roles in controlling water levels. The objective of this research is to develop a methodology to assess combined effect of multiple source flooding on flood probability and severity in urban areas and to establish a set of conditions that dictate urban flooding due to extreme climatic events. These conditions broadly combine physical flood drivers (such as coastal and fluvial processes), their mechanisms and thresholds defining flood severity. The two main physical processes controlling urban flooding: high sea water levels (coastal flooding) and high river flows (fluvial flooding), and their threshold values for which flood is likely to occur, are considered in this study. Contribution of coastal and fluvial drivers to flooding and their impacts are assessed in a two-step process. The first step involves frequency analysis and extreme value statistical modelling of storm surges, tides and river flows and ultimately the application of joint probability method to estimate joint exceedence return periods for combination of surges, tide and river flows. In the second step, a numerical model of Cork Harbour MSN_Flood comprising a cascade of four nested high-resolution models is used to perform simulation of flood inundation under numerous hypothetical coastal and fluvial flood scenarios. The risk of flooding is quantified based on a range of physical aspects such as the extent and depth of inundation (Apel et al

  1. Biomechanical benefits of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: A cadaveric study.

    PubMed

    Kim, Hyun-Min Mike; Chacon, Alexander C; Andrews, Seth H; Roush, Evan P; Cho, Edward; Conaway, William K; Kunselman, Allen R; Lewis, Gregory S

    2016-04-01

    Restoration of joint stability during total shoulder arthroplasty can be challenging in the face of severe glenoid retroversion. A novel technique of humeral head component anterior-offsetting has been proposed to address posterior instability. We evaluated the biomechanical benefits of this technique in cadaveric specimens. Total shoulder arthroplasty was performed in 14 cadaveric shoulders from 7 donors. Complementary shoulders were assigned to either 10° or 20° glenoid retroversion, with retroversion created by eccentric reaming. Two humeral head component offset positions were tested in each specimen: The anatomic (posterior) and anterior (reverse). With loads applied to the rotator cuff and deltoid, joint contact pressures and the force and energy required for posterior humeral head translation were measured. The force and energy required to displace the humeral head posteriorly increased significantly with the anterior offset position compared to the anatomic offset position. The joint contact pressures were significantly shifted anteriorly, and the joint contact area significantly increased with the anterior offset position. Anterior offsetting of the humeral head component increased the resistance to posterior humeral head translation, shifted joint contact pressures anteriorly, and increased joint contact area, thus, potentially increasing the joint stability in total shoulder arthroplasty with simulated glenoid retroversion. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  2. Cam impingement of the posterior femoral condyle in medial meniscal tears.

    PubMed

    Suganuma, Jun; Mochizuki, Ryuta; Yamaguchi, Kenji; Inoue, Yutaka; Yamabe, Eikou; Ueda, Yoshiyuki; Fujinaka, Tarou

    2010-02-01

    The aim of this study was to compare the results of meniscal repair of the medial meniscus with or without decompression of the posterior segment of the medial meniscus for the treatment of posteromedial tibiofemoral incongruence at full flexion (PMTFI), which induces deformation of the posterior segment on sagittal magnetic resonance imaging (MRI). For more than 2 years, we followed up 27 patients with PMTFI who were classified into the following 2 groups. Group 1 included 8 patients (5 male joints and 3 female joints) with a medial meniscal tear with instability at the site of the tear who underwent meniscal repair. The mean age was 23.6 years. Group 2 included 19 patients (16 male joints and 3 female joints) who had a meniscal tear with instability at the site of the tear and underwent meniscal repair and decompression. The mean age was 26.5 years. In decompression of the posterior segment, redundant bone tissue on the most proximal part of the medial femoral condyle was excised. The patients were assessed by use of the Lysholm score, sagittal MRI at full flexion, and arthroscopic examination. There were no statistical differences in mean Lysholm score between the 2 groups before surgery, but the mean score in group 2 was significantly higher than that in group 1 after surgery. Meniscal deformation of the posterior segment at full flexion on MRI disappeared in all cases after decompression. On second-look arthroscopy, the rate of complete healing at the site of the tear was 0% in group 1 but 57% in group 2, and it was significantly different between these groups. The addition of decompression of the posterior segment of the medial meniscus to meniscal repair of knee joints with PMTFI allowed more room for the medial meniscus to accommodate and improved both function of the knee joint and the rate of success of repair of isolated medial meniscal tears in patients who regularly performed full knee flexion. (c) 2010 Arthroscopy Association of North America

  3. Joint Segmentation and Deformable Registration of Brain Scans Guided by a Tumor Growth Model

    PubMed Central

    Gooya, Ali; Pohl, Kilian M.; Bilello, Michel; Biros, George; Davatzikos, Christos

    2011-01-01

    This paper presents an approach for joint segmentation and deformable registration of brain scans of glioma patients to a normal atlas. The proposed method is based on the Expectation Maximization (EM) algorithm that incorporates a glioma growth model for atlas seeding, a process which modifies the normal atlas into one with a tumor and edema. The modified atlas is registered into the patient space and utilized for the posterior probability estimation of various tissue labels. EM iteratively refines the estimates of the registration parameters, the posterior probabilities of tissue labels and the tumor growth model parameters. We have applied this approach to 10 glioma scans acquired with four Magnetic Resonance (MR) modalities (T1, T1-CE, T2 and FLAIR ) and validated the result by comparing them to manual segmentations by clinical experts. The resulting segmentations look promising and quantitatively match well with the expert provided ground truth. PMID:21995070

  4. Joint segmentation and deformable registration of brain scans guided by a tumor growth model.

    PubMed

    Gooya, Ali; Pohl, Kilian M; Bilello, Michel; Biros, George; Davatzikos, Christos

    2011-01-01

    This paper presents an approach for joint segmentation and deformable registration of brain scans of glioma patients to a normal atlas. The proposed method is based on the Expectation Maximization (EM) algorithm that incorporates a glioma growth model for atlas seeding, a process which modifies the normal atlas into one with a tumor and edema. The modified atlas is registered into the patient space and utilized for the posterior probability estimation of various tissue labels. EM iteratively refines the estimates of the registration parameters, the posterior probabilities of tissue labels and the tumor growth model parameters. We have applied this approach to 10 glioma scans acquired with four Magnetic Resonance (MR) modalities (T1, T1-CE, T2 and FLAIR) and validated the result by comparing them to manual segmentations by clinical experts. The resulting segmentations look promising and quantitatively match well with the expert provided ground truth.

  5. Joint probability of statistical success of multiple phase III trials.

    PubMed

    Zhang, Jianliang; Zhang, Jenny J

    2013-01-01

    In drug development, after completion of phase II proof-of-concept trials, the sponsor needs to make a go/no-go decision to start expensive phase III trials. The probability of statistical success (PoSS) of the phase III trials based on data from earlier studies is an important factor in that decision-making process. Instead of statistical power, the predictive power of a phase III trial, which takes into account the uncertainty in the estimation of treatment effect from earlier studies, has been proposed to evaluate the PoSS of a single trial. However, regulatory authorities generally require statistical significance in two (or more) trials for marketing licensure. We show that the predictive statistics of two future trials are statistically correlated through use of the common observed data from earlier studies. Thus, the joint predictive power should not be evaluated as a simplistic product of the predictive powers of the individual trials. We develop the relevant formulae for the appropriate evaluation of the joint predictive power and provide numerical examples. Our methodology is further extended to the more complex phase III development scenario comprising more than two (K > 2) trials, that is, the evaluation of the PoSS of at least k₀ (k₀≤ K) trials from a program of K total trials. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Tibiofemoral and patellofemoral joint 3D-kinematics in patients with posterior cruciate ligament deficiency compared to healthy volunteers.

    PubMed

    von Eisenhart-Rothe, Ruediger; Lenze, Ulrich; Hinterwimmer, Stefan; Pohlig, Florian; Graichen, Heiko; Stein, Thomas; Welsch, Frederic; Burgkart, Rainer

    2012-11-26

    The posterior cruciate ligament (PCL) plays an important role in maintaining physiological kinematics and function of the knee joint. To date mainly in-vitro models or combined magnetic resonance and fluoroscopic systems have been used for quantifying the importance of the PCL. We hypothesized, that both tibiofemoral and patellofemoral kinematic patterns are changed in PCL-deficient knees, which is increased by isometric muscle flexion. Therefore the aim of this study was to simultaneously investigate tibiofemoral and patellofemoral 3D kinematics in patients suffering from PCL deficiency during different knee flexion angles and under neuromuscular activation. We enrolled 12 patients with isolated PCL-insufficiency as well as 20 healthy volunteers. Sagittal MR-images of the knee joint were acquired in different positions of the knee joint (0°, 30°, 90° flexion, with and without flexing isometric muscle activity) on a 0.2 Tesla open MR-scanner. After segmentation of the patella, femur and tibia local coordinate systems were established to define the spatial position of these structures in relation to each other. At full extension and 30° flexion no significant difference was observed in PCL-deficient knee joints neither for tibiofemoral nor for patellofemoral kinematics. At 90° flexion the femur of PCL-deficient patients was positioned significantly more anteriorly in relation to the tibia and both, the patellar tilt and the patellar shift to the lateral side, significantly increased compared to healthy knee joints. While no significant effect of isometric flexing muscle activity was observed in healthy individuals, in PCL-deficient knee joints an increased paradoxical anterior translation of the femur was observed at 90° flexion compared to the status of muscle relaxation. Significant changes in tibiofemoral and patellofemoral joint kinematics occur in patients with isolated PCL-insufficiency above 30 degrees of flexion compared to healthy volunteers. Since

  7. Point-of-care ultrasound facilitates diagnosing a posterior shoulder dislocation.

    PubMed

    Mackenzie, David C; Liebmann, Otto

    2013-05-01

    Posterior shoulder dislocation is an uncommon disruption of the glenohumeral joint. Risk factors include seizure, electric shock, and underlying instabilities of the shoulder joint. A 27-year-old man with a history of recurrent posterior shoulder dislocation presented to the Emergency Department with sudden shoulder pain and reduced range of motion about the shoulder after abducting and internally rotating his arm. Radiographs did not show fracture or dislocation. The treating physician suspected an occult posterior shoulder dislocation, but wanted to avoid performing a computed tomography scan of the shoulder, as the patient had undergone numerous scans during the evaluation of similar complaints. Instead, a point-of-care ultrasound was performed, demonstrating posterior displacement of the humeral head relative to the glenoid rim, confirming the presence of a posterior shoulder dislocation. The patient received procedural sedation, and the shoulder was reduced with real-time ultrasound visualization. The patient tolerated the procedure well, and had decreased pain and improved range of motion. He was discharged with a sling, swathe, and orthopedic follow-up. Point-of-care ultrasound of the shoulder may be used to demonstrate posterior shoulder dislocation. This may have particular utility in the setting of non-diagnostic radiographs. Copyright © 2013. Published by Elsevier Inc.

  8. An Alternative Version of Conditional Probabilities and Bayes' Rule: An Application of Probability Logic

    ERIC Educational Resources Information Center

    Satake, Eiki; Amato, Philip P.

    2008-01-01

    This paper presents an alternative version of formulas of conditional probabilities and Bayes' rule that demonstrate how the truth table of elementary mathematical logic applies to the derivations of the conditional probabilities of various complex, compound statements. This new approach is used to calculate the prior and posterior probabilities…

  9. Interposition of the Posterior Cruciate Ligament into the Medial Compartment of the Knee Joint on Coronal Magnetic Resonance Imaging.

    PubMed

    Kim, Hyun Su; Yoon, Young Cheol; Park, Ki Jeong; Wang, Joon Ho; Choe, Bong-Keun

    2016-01-01

    The purpose of our study was to evaluate the overall prevalence and clinical significance of interposition of the posterior cruciate ligament (PCL) into the medial compartment of the knee joint in coronal magnetic resonance imaging (MRI). We retrospectively reviewed 317 consecutive patients referred for knee MRI at our institution between October 2009 and December 2009. Interposition of the PCL into the medial compartment of the knee joint on proton coronal MRI was evaluated dichotomously (i.e., present or absent). We analyzed the interposition according to its prevalence as well as its relationship with right-left sidedness, gender, age, and disease categories (osteoarthritis, anterior cruciate ligament tear, and medial meniscus tear). Prevalence of interposition of PCL into the medial compartment of the knee joint was 47.0% (149/317). There was no right (50.0%, 83/166) to left (43.7%, 66/151) or male (50.3%, 87/173) to female (43.1%, 62/144) differences in the prevalence. There was no significant association between the prevalence and age, or the disease categories. Interposition of the PCL into the medial compartment of the knee joint is observed in almost half of patients on proton coronal MRI of the knee. Its presence is not associated with any particular factors including knee pathology and may be regarded as a normal MR finding.

  10. Arthroscopic partial meniscectomy of a posteriorly flipped superior leaflet in a horizontal medial meniscus tear using a posterior transseptal portal.

    PubMed

    Jang, Ki-Mo; Ahn, Jin Hwan; Wang, Joon Ho

    2012-03-07

    This article describes a case of an arthroscopic partial meniscectomy of a posteriorly flipped superior leaflet in a horizontal medial meniscus tear using the posterior transseptal portal. An arthroscopic partial meniscectomy for bucket handle or flap tears in medial or lateral compartments using ordinary portals is a relatively common procedure in irreparable cases. However, the posterior compartment of the knee is not readily accessible through ordinary arthroscopic portals. Therefore, it has been considered a blind spot. Through the posterior transseptal portal, surgeons can achieve excellent arthroscopic visualization of the posterior compartment and easily perform arthroscopic procedures of the posterior compartment of the knee. A 48-year-old woman presented with a 1-year history of pain in the medial aspect of the right knee joint. Preoperative magnetic resonance imaging revealed a thinning of the medial meniscus posterior horn in coronal images and a sharp-edged triangle arising from the medial meniscus posterior horn between the medial femoral condyle and medial meniscus posterior horn on sagittal images (flipped-over sign). During the arthroscopic procedure, we found that the flipped leaflet was displaced posteriorly and was not mobile between the medial femoral condyle and medial meniscus posterior horn. Partial meniscectomy for a posteriorly displaced fragment can be performed successfully using the posterior transseptal portal. The posterior transseptal portal is useful for an arthroscopic partial meniscectomy of a posteriorly flipped leaflet in the posterior compartment of the knee. Copyright 2012, SLACK Incorporated.

  11. Biomechanical Effects of Posterior Condylar Offset and Posterior Tibial Slope on Quadriceps Force and Joint Contact Forces in Posterior-Stabilized Total Knee Arthroplasty.

    PubMed

    Kang, Kyoung-Tak; Koh, Yong-Gon; Son, Juhyun; Kwon, Oh-Ryong; Lee, Jun-Sang; Kwon, Sae Kwang

    2017-01-01

    This study aimed to determine the biomechanical effect of the posterior condylar offset (PCO) and posterior tibial slope (PTS) in posterior-stabilized (PS) fixed-bearing total knee arthroplasty (TKA). We developed ±1, ±2, and ±3 mm PCO models in the posterior direction and -3°, 0°, 3°, and 6° PTS models using a previously validated FE model. The influence of changes in the PCO and PTS on the biomechanical effects under deep-knee-bend loading was investigated. The contact stress on the PE insert increased by 14% and decreased by 7% on average as the PCO increased and decreased, respectively, compared to the neutral position. In addition, the contact stress on post in PE insert increased by 18% on average as PTS increased from -3° to 6°. However, the contact stress on the patellar button decreased by 11% on average as PTS increased from -3° to 6° in all different PCO cases. The quadriceps force decreased by 14% as PTS increased from -3° to 6° in all PCO models. The same trend was found in patellar tendon force. Changes in PCO had adverse biomechanical effects whereas PTS increase had positive biomechanical effects. However, excessive PTS should be avoided to prevent knee instability and subsequent failure.

  12. Biomechanical consequences of subtalar joint arthroereisis in treating posterior tibial tendon dysfunction: a theoretical analysis using finite element analysis.

    PubMed

    Wong, Duo Wai-Chi; Wang, Yan; Chen, Tony Lin-Wei; Leung, Aaron Kam-Lun; Zhang, Ming

    2017-11-01

    Subtalar joint arthroereisis (SJA) has been introduced to control the hyperpronation in cases of flatfoot. The objective of this study is to evaluate the biomechanical consequence of SJA to restore the internal stress and load transfer to the intact state from the attenuated biomechanical condition induced by posterior tibial tendon dysfunction (PTTD). A three-dimensional finite element model of the foot and ankle complex was constructed based on clinical images of a healthy female (age 28 years, height 165 cm, body mass 54 kg). The boundary and loading condition during walking was acquired from the gait experiment of the model subject. Five sets of simulations (conditions) were completed: intact condition, mild PTTD, severe PTTD, mild PTTD with SJA, severe PTTD with SJA. The maximum von Mises stress of the metatarsal shafts and the load transfer along the midfoot during stance were analyzed. Generally, SJA deteriorated the joint force of the medial cuneonavicular and calcaneocuboid joints during late stance, while that of the metatarsocuneiform joints during early stance were over-corrected. Only the calcaneocuboid joint force at 45% stance demonstrated a trend of improvement. Besides, SJA exaggerated the increased stress of the metatarsals compared to the PTTD conditions, except that of the first metatarsal. Our study did not support the hypothesis that SJA can restore the internal load transfer and midfoot stress. SJA cannot compensate the salvage of midfoot stability attributed by PTTD and could be biomechanically insufficient to restore the biomechanical environment. Additional procedures such as orthotic intervention may be necessary.

  13. Posterior impingement syndromes of the ankle.

    PubMed

    Lee, Justin C; Calder, James D F; Healy, Jeremiah C

    2008-06-01

    Acute, or repetitive, compression of the posterior structures of the ankle may lead to posterior ankle impingement (PAI) syndrome, posteromedial ankle impingement (PoMI) syndrome, or Haglund's syndrome. The etiology of each of these conditions is quite different. Variations in posterior ankle osseous and soft tissue anatomy contribute to the etiology of PAI and Haglund's syndromes. The presence of an os trigonum or Stieda process is classically associated with PAI syndrome, whereas a prominent posterosuperior tubercle of the os calcis or Haglund's deformity is the osseous predisposing factor in Haglund's syndrome. PoMI has no defined predisposing anatomical variants but typically follows an inversion-supination injury of the ankle joint. This article discusses the biomechanics, clinical features, imaging, and management of each of these conditions. Magnetic resonance imaging (MRI) provides the optimal tool in posterior ankle assessment, and this review focuses on the MRI findings of each of the conditions just listed.

  14. A Quantitative Exposure Planning Tool for Surgical Approaches to the Sacroiliac Joint.

    PubMed

    Phelps, Kevin D; Ming, Bryan W; Fox, Wade E; Bellamy, Nelly; Sims, Stephen H; Karunakar, Madhav A; Hsu, Joseph R

    2016-06-01

    To aid in surgical planning by quantifying and comparing the osseous exposure between the anterior and posterior approaches to the sacroiliac joint. Anterior and posterior approaches were performed on 12 sacroiliac joints in 6 fresh-frozen torsos. Visual and palpable access to relevant surgical landmarks was recorded. Calibrated digital photographs were taken of each approach and analyzed using Image J. The average surface areas of exposed bone were 44 and 33 cm for the anterior and posterior approaches, respectively. The anterior iliolumbar ligament footprint could be visualized in all anterior approaches, whereas the posterior aspect could be visualized in all but one posterior approach. The anterior approach provided visual and palpable access to the anterior superior edge of the sacroiliac joint in all specimens, the posterior superior edge in 75% of specimens, and the inferior margin in 25% and 50% of specimens, respectively. The inferior sacroiliac joint was easily visualized and palpated in all posterior approaches, although access to the anterior and posterior superior edges was more limited. The anterior S1 neuroforamen was not visualized with either approach and was more consistently palpated when going posterior (33% vs. 92%). Both anterior and posterior approaches can be used for open reduction of pure sacroiliac dislocations, each with specific areas for assessing reduction. In light of current plate dimensions, fractures more than 2.5 cm lateral to the anterior iliolumbar ligament footprint are amenable to anterior plate fixation, whereas those more medial may be better addressed through a posterior approach.

  15. Experimental investigation of the intensity fluctuation joint probability and conditional distributions of the twin-beam quantum state.

    PubMed

    Zhang, Yun; Kasai, Katsuyuki; Watanabe, Masayoshi

    2003-01-13

    We give the intensity fluctuation joint probability of the twin-beam quantum state, which was generated with an optical parametric oscillator operating above threshold. Then we present what to our knowledge is the first measurement of the intensity fluctuation conditional probability distributions of twin beams. The measured inference variance of twin beams 0.62+/-0.02, which is less than the standard quantum limit of unity, indicates inference with a precision better than that of separable states. The measured photocurrent variance exhibits a quantum correlation of as much as -4.9+/-0.2 dB between the signal and the idler.

  16. Open capsular and ligament reconstruction with semitendinosus hamstring autograft successfully controls superior and posterior translation for type V acromioclavicular joint dislocation.

    PubMed

    Garofalo, Raffaele; Ceccarelli, Enrico; Castagna, Alessandro; Calvisi, Vittorio; Flanagin, Brody; Conti, Marco; Krishnan, Sumant G

    2017-07-01

    Appropriate surgical management for type V complete acromioclavicular (AC) joint dislocation remains controversial. The purpose of this paper is to retrospectively report the clinical and radiographic outcomes of an open surgical technique consisting for AC joint ligamentous and capsular reconstruction using autologous hamstring tendon grafts and semi-permanent sutures. Between January 2005 and December 2011, 32 consecutive patients with symptomatic type V complete AC joint dislocation underwent surgical treatment using the same technique. The median time from injury to surgery was 45 days (range 24-90). The average median postoperative clinical and radiographic follow-up time was 30 months (range 24-33). Clinical outcomes measures included the ASES score, the visual analog score (VAS), and subjective patient satisfaction score. Minimum follow-up was 2 years. ASES score increased from a median of 38.2 ± 6.2 preoperative to 92.1 ± 4.7 postoperatively (p ≤ 0.05). The median VAS score improved from 62 mm (range 45-100 mm) preoperatively to 8 mm (range 0-20 mm) at final follow-up (p ≤ 0.05). No patient experienced pain or discomfort with either direct palpation of the AC joint or with cross-body adduction. Final radiographs demonstrated symmetric AC joint contour in 25/32 (78%) patients. Seven patients (22%) radiographically demonstrated superior translation of the distal clavicle relative to the superior margin of the acromion but less than 50% of the clavicular width. 30/32 patients (93%) were able to return to their pre-injury level of work and sports activities. This novel surgical technique using a free graft and braided suture for simultaneous coracoclavicular ligament and AC joint capsular reconstruction successfully controls superior and posterior translations after type V AC joint dislocation and minimizes the incidence of persistent postoperative AC joint subluxation. Retrospective case series, Level IV.

  17. Multiple model cardinalized probability hypothesis density filter

    NASA Astrophysics Data System (ADS)

    Georgescu, Ramona; Willett, Peter

    2011-09-01

    The Probability Hypothesis Density (PHD) filter propagates the first-moment approximation to the multi-target Bayesian posterior distribution while the Cardinalized PHD (CPHD) filter propagates both the posterior likelihood of (an unlabeled) target state and the posterior probability mass function of the number of targets. Extensions of the PHD filter to the multiple model (MM) framework have been published and were implemented either with a Sequential Monte Carlo or a Gaussian Mixture approach. In this work, we introduce the multiple model version of the more elaborate CPHD filter. We present the derivation of the prediction and update steps of the MMCPHD particularized for the case of two target motion models and proceed to show that in the case of a single model, the new MMCPHD equations reduce to the original CPHD equations.

  18. A Bayesian joint probability modeling approach for seasonal forecasting of streamflows at multiple sites

    NASA Astrophysics Data System (ADS)

    Wang, Q. J.; Robertson, D. E.; Chiew, F. H. S.

    2009-05-01

    Seasonal forecasting of streamflows can be highly valuable for water resources management. In this paper, a Bayesian joint probability (BJP) modeling approach for seasonal forecasting of streamflows at multiple sites is presented. A Box-Cox transformed multivariate normal distribution is proposed to model the joint distribution of future streamflows and their predictors such as antecedent streamflows and El Niño-Southern Oscillation indices and other climate indicators. Bayesian inference of model parameters and uncertainties is implemented using Markov chain Monte Carlo sampling, leading to joint probabilistic forecasts of streamflows at multiple sites. The model provides a parametric structure for quantifying relationships between variables, including intersite correlations. The Box-Cox transformed multivariate normal distribution has considerable flexibility for modeling a wide range of predictors and predictands. The Bayesian inference formulated allows the use of data that contain nonconcurrent and missing records. The model flexibility and data-handling ability means that the BJP modeling approach is potentially of wide practical application. The paper also presents a number of statistical measures and graphical methods for verification of probabilistic forecasts of continuous variables. Results for streamflows at three river gauges in the Murrumbidgee River catchment in southeast Australia show that the BJP modeling approach has good forecast quality and that the fitted model is consistent with observed data.

  19. Color object detection using spatial-color joint probability functions.

    PubMed

    Luo, Jiebo; Crandall, David

    2006-06-01

    Object detection in unconstrained images is an important image understanding problem with many potential applications. There has been little success in creating a single algorithm that can detect arbitrary objects in unconstrained images; instead, algorithms typically must be customized for each specific object. Consequently, it typically requires a large number of exemplars (for rigid objects) or a large amount of human intuition (for nonrigid objects) to develop a robust algorithm. We present a robust algorithm designed to detect a class of compound color objects given a single model image. A compound color object is defined as having a set of multiple, particular colors arranged spatially in a particular way, including flags, logos, cartoon characters, people in uniforms, etc. Our approach is based on a particular type of spatial-color joint probability function called the color edge co-occurrence histogram. In addition, our algorithm employs perceptual color naming to handle color variation, and prescreening to limit the search scope (i.e., size and location) for the object. Experimental results demonstrated that the proposed algorithm is insensitive to object rotation, scaling, partial occlusion, and folding, outperforming a closely related algorithm based on color co-occurrence histograms by a decisive margin.

  20. Surgical anatomy of the sternoclavicular joint: a qualitative and quantitative anatomical study.

    PubMed

    Lee, Jared T; Campbell, Kevin J; Michalski, Max P; Wilson, Katharine J; Spiegl, Ulrich J A; Wijdicks, Coen A; Millett, Peter J

    2014-10-01

    The quantitative anatomical relationships of the main ligamentous, tendinous, and osseous structures of the sternoclavicular joint have not been widely investigated. The purpose of this study was to provide a quantitative description of the sternoclavicular joint in relation to relevant surgical landmarks. We dissected eleven nonpaired, fresh-frozen cadaveric sternoclavicular joints from four men and seven women (mean age at death, fifty-three years; range, thirty-three to sixty-four years) and measured the ligaments, musculature, and osseous landmarks with use of a three-dimensional coordinate-measuring device. The clavicular pectoralis ridge, located at the 9:30 clock-face position on a right clavicle, served as a reliable osseous landmark for reference to the soft-tissue attachments around the sternoclavicular joint. The costoclavicular ligament was the largest ligament of the sternoclavicular joint, with 80% greater footprint area than that of the posterior sternoclavicular ligament. Articular cartilage covered 67% of the medial end of the clavicle and was located anteroinferiorly. The sternohyoid muscle inserted directly over the posterior sternoclavicular joint and the medial end of the clavicle, whereas the sternothyroid muscle inserted 9.5 mm inferior to the posterior-superior articular margin of the manubrium and coursed 19.8 mm laterally along the first rib. An avascular plane that can serve as a "safe zone" for posterior dissection was observed in each specimen, posterior to the sternoclavicular joint and anterior to the sternohyoid and sternothyroid muscles. The clavicular pectoralis ridge can be used as an intraoperative guide for clavicle orientation and tunnel placement in sternoclavicular ligament reconstruction. Sternoclavicular joint resection arthroplasty should avoid injuring the costoclavicular ligament, which is the largest sternoclavicular joint ligament. Resection of only the anteroinferior aspect of the medial end of the clavicle may

  1. International comparative evaluation of knee replacement with fixed or mobile-bearing posterior-stabilized prostheses.

    PubMed

    Graves, Stephen; Sedrakyan, Art; Baste, Valborg; Gioe, Terence J; Namba, Robert; Martínez Cruz, Olga; Stea, Susanna; Paxton, Elizabeth; Banerjee, Samprit; Isaacs, Abby J; Robertsson, Otto

    2014-12-17

    Posterior-stabilized total knee prostheses were introduced to address instability secondary to loss of posterior cruciate ligament function, and they have either fixed or mobile bearings. Mobile bearings were developed to improve the function and longevity of total knee prostheses. In this study, the International Consortium of Orthopaedic Registries used a distributed health data network to study a large cohort of posterior-stabilized prostheses to determine if the outcome of a posterior-stabilized total knee prosthesis differs depending on whether it has a fixed or mobile-bearing design. Aggregated registry data were collected with a distributed health data network that was developed by the International Consortium of Orthopaedic Registries to reduce barriers to participation (e.g., security, proprietary, legal, and privacy issues) that have the potential to occur with the alternate centralized data warehouse approach. A distributed health data network is a decentralized model that allows secure storage and analysis of data from different registries. Each registry provided data on mobile and fixed-bearing posterior-stabilized prostheses implanted between 2001 and 2010. Only prostheses associated with primary total knee arthroplasties performed for the treatment of osteoarthritis were included. Prostheses with all types of fixation were included except for those with the rarely used reverse hybrid (cementless tibial and cemented femoral components) fixation. The use of patellar resurfacing was reported. The outcome of interest was time to first revision (for any reason). Multivariate meta-analysis was performed with linear mixed models with survival probability as the unit of analysis. This study includes 137,616 posterior-stabilized knee prostheses; 62% were in female patients, and 17.6% had a mobile bearing. The results of the fixed-effects model indicate that in the first year the mobile-bearing posterior-stabilized prostheses had a significantly higher hazard

  2. Pig Data and Bayesian Inference on Multinomial Probabilities

    ERIC Educational Resources Information Center

    Kern, John C.

    2006-01-01

    Bayesian inference on multinomial probabilities is conducted based on data collected from the game Pass the Pigs[R]. Prior information on these probabilities is readily available from the instruction manual, and is easily incorporated in a Dirichlet prior. Posterior analysis of the scoring probabilities quantifies the discrepancy between empirical…

  3. Naive Probability: A Mental Model Theory of Extensional Reasoning.

    ERIC Educational Resources Information Center

    Johnson-Laird, P. N.; Legrenzi, Paolo; Girotto, Vittorio; Legrenzi, Maria Sonino; Caverni, Jean-Paul

    1999-01-01

    Outlines a theory of naive probability in which individuals who are unfamiliar with the probability calculus can infer the probabilities of events in an "extensional" way. The theory accommodates reasoning based on numerical premises, and explains how naive reasoners can infer posterior probabilities without relying on Bayes's theorem.…

  4. Technology-enhanced Interactive Teaching of Marginal, Joint and Conditional Probabilities: The Special Case of Bivariate Normal Distribution

    PubMed Central

    Dinov, Ivo D.; Kamino, Scott; Bhakhrani, Bilal; Christou, Nicolas

    2014-01-01

    Summary Data analysis requires subtle probability reasoning to answer questions like What is the chance of event A occurring, given that event B was observed? This generic question arises in discussions of many intriguing scientific questions such as What is the probability that an adolescent weighs between 120 and 140 pounds given that they are of average height? and What is the probability of (monetary) inflation exceeding 4% and housing price index below 110? To address such problems, learning some applied, theoretical or cross-disciplinary probability concepts is necessary. Teaching such courses can be improved by utilizing modern information technology resources. Students’ understanding of multivariate distributions, conditional probabilities, correlation and causation can be significantly strengthened by employing interactive web-based science educational resources. Independent of the type of a probability course (e.g. majors, minors or service probability course, rigorous measure-theoretic, applied or statistics course) student motivation, learning experiences and knowledge retention may be enhanced by blending modern technological tools within the classical conceptual pedagogical models. We have designed, implemented and disseminated a portable open-source web-application for teaching multivariate distributions, marginal, joint and conditional probabilities using the special case of bivariate Normal distribution. A real adolescent height and weight dataset is used to demonstrate the classroom utilization of the new web-application to address problems of parameter estimation, univariate and multivariate inference. PMID:25419016

  5. Technology-enhanced Interactive Teaching of Marginal, Joint and Conditional Probabilities: The Special Case of Bivariate Normal Distribution.

    PubMed

    Dinov, Ivo D; Kamino, Scott; Bhakhrani, Bilal; Christou, Nicolas

    2013-01-01

    Data analysis requires subtle probability reasoning to answer questions like What is the chance of event A occurring, given that event B was observed? This generic question arises in discussions of many intriguing scientific questions such as What is the probability that an adolescent weighs between 120 and 140 pounds given that they are of average height? and What is the probability of (monetary) inflation exceeding 4% and housing price index below 110? To address such problems, learning some applied, theoretical or cross-disciplinary probability concepts is necessary. Teaching such courses can be improved by utilizing modern information technology resources. Students' understanding of multivariate distributions, conditional probabilities, correlation and causation can be significantly strengthened by employing interactive web-based science educational resources. Independent of the type of a probability course (e.g. majors, minors or service probability course, rigorous measure-theoretic, applied or statistics course) student motivation, learning experiences and knowledge retention may be enhanced by blending modern technological tools within the classical conceptual pedagogical models. We have designed, implemented and disseminated a portable open-source web-application for teaching multivariate distributions, marginal, joint and conditional probabilities using the special case of bivariate Normal distribution. A real adolescent height and weight dataset is used to demonstrate the classroom utilization of the new web-application to address problems of parameter estimation, univariate and multivariate inference.

  6. Soft tissue-based surgical techniques for treatment of posterior shoulder instability.

    PubMed

    Castagna, Alessandro; Conti, Marco; Garofalo, Raffaele

    2017-01-01

    Posterior shoulder instability is a rare clinical condition that encompasses different degrees of severity including various possible pathologies involving the labrum, capsule, bony lesions, and even locked posterior dislocation. When focusing on soft tissue involvement, the diagnosis of posterior instability may be difficult to make because frequently patients report vague symptoms not associated with a clear history of traumatic shoulder dislocation. Pathological soft tissue conditions associated with posterior instability in most cases are related to posterior labral tear and/or posterior capsular detensioning/tear. The diagnosis can be facilitated by physical examination using specific clinical tests (i. e., jerk test, Kim test, and reinterpreted O'Brien test) together with appropriate imaging studies (i. e., magnetic resonance arthrography). Arthroscopy may help in a complete evaluation of the joint and allows for the treatment of soft tissue lesions in posterior instability. Caution is warranted in the case of concomitant posterior glenoid chondral defect as a potential cause of poor outcome after soft tissue repair in posterior instability.

  7. Posterior shoulder instability managed by arthroscopic acromial pediculated bone-block. Technique.

    PubMed

    Métais, P; Grimberg, J; Clavert, P; Kouvalchouk, J-F; Sirveaux, F; Nourissat, G; Garret, J; Mansat, P; Godenèche, A

    2017-12-01

    In posterior shoulder instability (recurrent dislocation, involuntary posterior subluxation or voluntary subluxation that has become involuntary), surgery may be considered in case of failure of functional treatment if there are no psychological contraindications. Acromial bone-block with pediculated deltoid flap, as described by Kouvalchouk, is an alternative to iliac bone-block, enabling triple shoulder locking by the blocking effect, the retention hammock provided by the deltoid flap and posterior capsule repair. Arthroscopy allows shoulder joint exploration and diagnosis of associated lesions, with opening and conservation of the posterior capsule; it greatly facilitates bone-block positioning and capsule reinsertion. The present report describes the procedure in detail. Technical note. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. New meniscus repair technique for peripheral tears near the posterior tibial attachment of the posterior horn of the medial meniscus.

    PubMed

    Park, In-Seop; Kim, Sung-Jae

    2006-08-01

    We introduce a suture technique to repair a peripheral tear near the posterior tibial attachment of the posterior horn. A suture hook was inserted through the posteromedial portal, and the peripheral capsular rim was penetrated from superior to inferior by the sharp hook. Both relay limbs were brought out through the posteromedial portal. The outer limb of the superior peripheral capsular rim was identified with a hemostat. An 18-gauge spinal needle loaded with a No. 0 polydioxanone suture (PDS) was introduced into the joint from the anteromedial portal; it was passed through the joint space until it penetrated the inner torn meniscus. The PDS suture loaded within the needle was pushed into the joint and picked up through the posteromedial portal. The needle was pulled out of the torn meniscus and readvanced over it while the suture was kept loaded. The other limb of the suture from the tip of the spinal needle was retrieved through the posteromedial portal. The initial PDS suture limb was hooked to the shuttle-relay system; it then was passed through the inner torn meniscus and the peripheral capsular rim. The suture limb exiting from the peripheral capsular rim was used as a post and was joined to the other suture limb to form a sliding knot.

  9. Joint time/frequency-domain inversion of reflection data for seabed geoacoustic profiles and uncertainties.

    PubMed

    Dettmer, Jan; Dosso, Stan E; Holland, Charles W

    2008-03-01

    This paper develops a joint time/frequency-domain inversion for high-resolution single-bounce reflection data, with the potential to resolve fine-scale profiles of sediment velocity, density, and attenuation over small seafloor footprints (approximately 100 m). The approach utilizes sequential Bayesian inversion of time- and frequency-domain reflection data, employing ray-tracing inversion for reflection travel times and a layer-packet stripping method for spherical-wave reflection-coefficient inversion. Posterior credibility intervals from the travel-time inversion are passed on as prior information to the reflection-coefficient inversion. Within the reflection-coefficient inversion, parameter information is passed from one layer packet inversion to the next in terms of marginal probability distributions rotated into principal components, providing an efficient approach to (partially) account for multi-dimensional parameter correlations with one-dimensional, numerical distributions. Quantitative geoacoustic parameter uncertainties are provided by a nonlinear Gibbs sampling approach employing full data error covariance estimation (including nonstationary effects) and accounting for possible biases in travel-time picks. Posterior examination of data residuals shows the importance of including data covariance estimates in the inversion. The joint inversion is applied to data collected on the Malta Plateau during the SCARAB98 experiment.

  10. Computer guided restoration of joint line and femoral offset in cruciate substituting total knee arthroplasty.

    PubMed

    Shetty, Gautam M; Mullaji, Arun; Bhayde, Sagar

    2012-10-01

    This prospective study aimed to evaluate radiographically, change in joint line and femoral condylar offset with the optimized gap balancing technique in computer-assisted, primary, cruciate-substituting total knee arthroplasties (TKAs). One hundred and twenty-nine consecutive computer-assisted TKAs were evaluated radiographically using pre- and postoperative full-length standing hip-to-ankle, antero-posterior and lateral radiographs to assess change in knee deformity, joint line height and posterior condylar offset. In 49% of knees, there was a net decrease (mean 2.2mm, range 0.2-8.4mm) in joint line height postoperatively whereas 46.5% of knees had a net increase in joint line height (mean 2.5mm, range 0.2-11.2mm). In 93% of the knees, joint line was restored to within ± 5 mm of preoperative values. In 53% of knees, there was a net increase (mean 2.9 mm, range 0.2-12 mm) in posterior offset postoperatively whereas 40% of knees had a net decrease in posterior offset (mean 4.2mm, range 0.6-20mm). In 82% of knees, the posterior offset was restored within ± 5 mm of preoperative values. Based on radiographic evaluation in extension and at 30° flexion, the current study clearly demonstrates that joint line and posterior femoral condylar offset can be restored in the majority of computer-assisted, cruciate-substituting TKAs to within 5mm of their preoperative value. The optimized gap balancing feature of the computer software allows the surgeon to simulate the effect of simultaneously adjusting femoral component size, position and distal femoral resection level on joint line and posterior femoral offset. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Temporal gene expression profiling of the rat knee joint capsule during immobilization-induced joint contractures.

    PubMed

    Wong, Kayleigh; Sun, Fangui; Trudel, Guy; Sebastiani, Paola; Laneuville, Odette

    2015-05-26

    Contractures of the knee joint cause disability and handicap. Recovering range of motion is recognized by arthritic patients as their preference for improved health outcome secondary only to pain management. Clinical and experimental studies provide evidence that the posterior knee capsule prevents the knee from achieving full extension. This study was undertaken to investigate the dynamic changes of the joint capsule transcriptome during the progression of knee joint contractures induced by immobilization. We performed a microarray analysis of genes expressed in the posterior knee joint capsule following induction of a flexion contracture by rigidly immobilizing the rat knee joint over a time-course of 16 weeks. Fold changes of expression values were measured and co-expressed genes were identified by clustering based on time-series analysis. Genes associated with immobilization were further analyzed to reveal pathways and biological significance and validated by immunohistochemistry on sagittal sections of knee joints. Changes in expression with a minimum of 1.5 fold changes were dominated by a decrease in expression for 7732 probe sets occurring at week 8 while the expression of 2251 probe sets increased. Clusters of genes with similar profiles of expression included a total of 162 genes displaying at least a 2 fold change compared to week 1. Functional analysis revealed ontology categories corresponding to triglyceride metabolism, extracellular matrix and muscle contraction. The altered expression of selected genes involved in the triglyceride biosynthesis pathway; AGPAT-9, and of the genes P4HB and HSP47, both involved in collagen synthesis, was confirmed by immunohistochemistry. Gene expression in the knee joint capsule was sensitive to joint immobility and provided insights into molecular mechanisms relevant to the pathophysiology of knee flexion contractures. Capsule responses to immobilization was dynamic and characterized by modulation of at least three

  12. Effects of medial meniscus posterior horn avulsion and repair on tibiofemoral contact area and peak contact pressure with clinical implications.

    PubMed

    Marzo, John M; Gurske-DePerio, Jennifer

    2009-01-01

    Avulsion of the posterior horn attachment of the medial meniscus can compromise load-bearing ability, produce meniscus extrusion, and result in tibiofemoral joint-space narrowing, articular cartilage damage, and osteoarthritis. Avulsion of the posterior horn of the medial meniscus will increase peak contact pressure and decrease contact area in the medial compartment of the knee, and posterior horn repair will restore contact area and peak contact pressures to values of the control knee. Controlled laboratory study. Eight fresh-frozen human cadaveric knees had tibiofemoral peak contact pressures and contact area measured in the control state. The posterior horn of the medial meniscus was avulsed from its insertion and knees were retested. The meniscal avulsion was repaired by suture through a transosseous tunnel and the knees were tested a third time. Avulsion of the posterior horn attachment of the medial meniscus resulted in a significant increase in medial joint peak contact pressure (from 3841 kPa to 5084 kPa) and a significant decrease in contact area (from 594 mm(2) to 474 mm(2)). Repair of the avulsion resulted in restoration of the loading profiles to values equal to the control knee, with values of 3551 kPa for peak pressure and 592 mm(2) for contact area. Posterior horn medial meniscal root avulsion leads to deleterious alteration of the loading profiles of the medial joint compartment and results in loss of hoop stress resistance, meniscus extrusion, abnormal loading of the joint, and early knee medial-compartment degenerative changes. The repair technique described restores the ability of the medial meniscus to absorb hoop stress and eliminate joint-space narrowing, possibly decreasing the risk of degenerative disease.

  13. International comparative evaluation of fixed-bearing non-posterior-stabilized and posterior-stabilized total knee replacements.

    PubMed

    Comfort, Thomas; Baste, Valborg; Froufe, Miquel Angel; Namba, Robert; Bordini, Barbara; Robertsson, Otto; Cafri, Guy; Paxton, Elizabeth; Sedrakyan, Art; Graves, Stephen

    2014-12-17

    to one: HR = 1.75, 95% CI = 1.27 to 2.42, p = 0.001; year one to two: HR = 1.31, 95% CI = 1.19 to 1.45, p < 0.001). There was a reduced risk of revision with a patient age of more than sixty-five years (HR = 0.57, 95% CI = 0.55 to 0.60, p < 0.001). We found that fixed non-posterior-stabilized total knee arthroplasty performed better with or without patellar resurfacing than did fixed posterior-stabilized total knee arthroplasty. This effect was most pronounced in the first two years. The risk of revision for posterior-stabilized total knee arthroplasties was reduced with patellar resurfacing. Also, a patient age of more than sixty-five years and female gender reduced the risk of revision. Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.

  14. A Cadaveric Study on Sacroiliac Joint Injection

    PubMed Central

    Zou, Yu-Cong; Li, Yi-Kai; Yu, Cheng-Fu; Yang, Xian-Wen; Chen, Run-Qi

    2015-01-01

    The scope of this study was to explore the possibility as well as the feasibility of sacroiliac joint injection following simple X-ray clip location. For the cadaveric study, 10 fixed sacroiliac joint (SIJ) sectional specimens, 4 dried cadaveric pelvises and 21 embalmed adult cadaveric pelvises were dissected, followed by an injection of contrast agent into the joint. The irrigation of the agent was observed through CT scanning. For the radiologic study, 188 CT scans of ankylosing spondylitis patients (143 male, 45 female) were collected from 2010 to 2012, in Nanfang Hospital. What was measured was (1) Distance between the posterior midline and sagittal synovium; (2) Length of the sagittal synovium; (3) Distance between the midpoint of the sagittal synovium and posterior superior iliac spine; and (4) Distance between the superficial skin vertical to the sagittal synovium point were measured. For the practice-based study: 20 patients (17 males and 3 females) with early ankylosing spondylitis, from Nanfang Hospital affiliated with Southern Medical University were recruited, and sacroiliac joint unguided injections were done on the basis of the cadaveric and radiologic study. Only the inferior 1/3rd portion parallel to the posterior midline could be injected into since the superior 2/3rd portion were filled with interosseous ligaments. Thirteen of the 20 patients received successful injections as identified by CT scan using the contrast agent. Sacroiliac joint injection following simple X-ray clip location is possible and feasible if the operation is performed by trained physicians familiar with the sacroiliac joint and its surrounding anatomic structures. PMID:25692437

  15. Effect of Retrograde Reaming for Tibiotalocalcaneal Arthrodesis on Subtalar Joint Destruction: A Cadaveric Study.

    PubMed

    Lowe, Jason A; Routh, Lucas K; Leary, Jeffrey T; Buzhardt, Paul C

    2016-01-01

    Recent published data have suggested successful union of subtalar and tibiotalar joints without formal debridement during tibiotalocalcaneal (TTC) fusion procedures. Although previous studies have reported on the importance of the proper guidewire starting point and trajectory to obtain appropriate hindfoot alignment for successful fusion, to our knowledge, no studies have quantified the amount of articular damage to the subtalar joint with retrograde reaming. We hypothesized that reaming would destroy >50% of the posterior facet of the subtalar joint. The bilateral lower extremities of 5 cadavers were obtained and the subtalar joints exposed. Retrograde TTC nail guidewires were inserted, and a 12-mm reamer was passed through the subtalar and ankle joints. Pre- and postreaming images of the subtalar joint were obtained to compare the amount of joint destruction after reaming. We found an average of 5.89% articular destruction of the talar posterior facet and an average of 4.01% articular destruction of the posterior facet of the calcaneus. No damage to the middle facets of the subtalar joint was observed. TTC nailing is a successful procedure for ankle and subtalar joint fusion. Published studies have reported successful subtalar union using TTC nailing without formal open debridement of the subtalar joint, preserving the soft tissue envelope. TTC nail insertion using a 12-mm reamer will destroy 5.89% and 4.01% of the respective talar and calcaneal posterior facets of the subtalar joint. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  16. Serial Spike Time Correlations Affect Probability Distribution of Joint Spike Events.

    PubMed

    Shahi, Mina; van Vreeswijk, Carl; Pipa, Gordon

    2016-01-01

    Detecting the existence of temporally coordinated spiking activity, and its role in information processing in the cortex, has remained a major challenge for neuroscience research. Different methods and approaches have been suggested to test whether the observed synchronized events are significantly different from those expected by chance. To analyze the simultaneous spike trains for precise spike correlation, these methods typically model the spike trains as a Poisson process implying that the generation of each spike is independent of all the other spikes. However, studies have shown that neural spike trains exhibit dependence among spike sequences, such as the absolute and relative refractory periods which govern the spike probability of the oncoming action potential based on the time of the last spike, or the bursting behavior, which is characterized by short epochs of rapid action potentials, followed by longer episodes of silence. Here we investigate non-renewal processes with the inter-spike interval distribution model that incorporates spike-history dependence of individual neurons. For that, we use the Monte Carlo method to estimate the full shape of the coincidence count distribution and to generate false positives for coincidence detection. The results show that compared to the distributions based on homogeneous Poisson processes, and also non-Poisson processes, the width of the distribution of joint spike events changes. Non-renewal processes can lead to both heavy tailed or narrow coincidence distribution. We conclude that small differences in the exact autostructure of the point process can cause large differences in the width of a coincidence distribution. Therefore, manipulations of the autostructure for the estimation of significance of joint spike events seem to be inadequate.

  17. Serial Spike Time Correlations Affect Probability Distribution of Joint Spike Events

    PubMed Central

    Shahi, Mina; van Vreeswijk, Carl; Pipa, Gordon

    2016-01-01

    Detecting the existence of temporally coordinated spiking activity, and its role in information processing in the cortex, has remained a major challenge for neuroscience research. Different methods and approaches have been suggested to test whether the observed synchronized events are significantly different from those expected by chance. To analyze the simultaneous spike trains for precise spike correlation, these methods typically model the spike trains as a Poisson process implying that the generation of each spike is independent of all the other spikes. However, studies have shown that neural spike trains exhibit dependence among spike sequences, such as the absolute and relative refractory periods which govern the spike probability of the oncoming action potential based on the time of the last spike, or the bursting behavior, which is characterized by short epochs of rapid action potentials, followed by longer episodes of silence. Here we investigate non-renewal processes with the inter-spike interval distribution model that incorporates spike-history dependence of individual neurons. For that, we use the Monte Carlo method to estimate the full shape of the coincidence count distribution and to generate false positives for coincidence detection. The results show that compared to the distributions based on homogeneous Poisson processes, and also non-Poisson processes, the width of the distribution of joint spike events changes. Non-renewal processes can lead to both heavy tailed or narrow coincidence distribution. We conclude that small differences in the exact autostructure of the point process can cause large differences in the width of a coincidence distribution. Therefore, manipulations of the autostructure for the estimation of significance of joint spike events seem to be inadequate. PMID:28066225

  18. Posterior Branches of Lumbar Spinal Nerves - Part I: Anatomy and Functional Importance.

    PubMed

    Kozera, Katarzyna; Ciszek, Bogdan

    2016-01-01

    The aim of this paper is to compare anatomic descriptions of posterior branches of the lumbar spinal nerves and, on this basis, present the location of these structures. The majority of anatomy textbooks do not describe these nerves in detail, which may be attributable to the fact that for many years they were regarded as structures of minor clinical importance. The state of knowledge on these nerves has changed within the last 30 years. Attention has been turned to their function and importance for both diagnostic practice and therapy of lower back pain. Summarising the available literature, we may conclude that the medial and lateral branches separate at the junction of the facet joint and the distal upper edge of the transverse process; that the size, course and area supplied differ between the lateral and the medial branch; and that facet joints receive multisegmental innervation. It has been demonstrated that medial branches are smaller than the respective lateral branches and they have a more constant course. Medial branches supply the area from the midline to the facet joint line, while lateral branches innervate tissues lateral to the facet joint. The literature indicates difficulties with determining specific anatomic landmarks relative to which the lateral branch and the distal medial branch can be precisely located. Irritation of sensory fibres within posterior branches of the lumbar spinal nerves may be caused by pathology of facet joints, deformity of the spine or abnormalities due to overloading or injury. The anatomic location and course of posterior branches of spinal nerves should be borne in mind to prevent damaging them during low-invasive analgesic procedures.

  19. The posterior transtriceps approach for elbow arthrography: a forgotten technique?

    PubMed

    Lohman, M; Borrero, C; Casagranda, B; Rafiee, B; Towers, J

    2009-05-01

    To evaluate the technical feasibility of performing elbow MR arthrography via a posterior approach through the triceps. The images of 19 patients with elbow MR arthrography via a posterior transtriceps approach were retrospectively studied. The injections were performed by four musculoskeletal radiologists, using fluoroscopic guidance and a 22- or 25-gauge needle. The fluoroscopic and subsequent MR images were reviewed by two musculoskeletal radiologists and evaluated for adequacy of joint capsular distention, degree and location of contrast leakage, and presence of gas bubbles. The injection was diagnostic in all 19 patients, with a sufficient amount of contrast agent seen in the elbow joint. No significant contrast leakage occurred in 12 patients who received injections of 8 cc or less of contrast agent, but moderate contrast leakage occurred in 6/7 patients who received injections of greater than 8 cc. Contrast leakage generally occurred within the triceps myotendinous junction. No gas bubbles were identified in the injected joints. Patients often present for MR arthrography of the elbow with medial or lateral elbow pain. Contrast leakage during a radiocapitellar approach may complicate evaluation of the lateral collateral ligament or the common extensor tendon origin. Transtriceps MR arthrography offers an alternative to the more commonly used radiocapitellar approach. With injected volumes not exceeding 8 cc, the risk of significant contrast leakage is small. An advantage of the transtriceps injection is that contrast leakage through the posterior needle tract does not interfere with evaluation of the lateral structures.

  20. Condyle fossa relationship associated with functional posterior crossbite, before and after rapid maxillary expansion.

    PubMed

    Leonardi, Rosalia; Caltabiano, Mario; Cavallini, Costanza; Sicurezza, Edoardo; Barbato, Ersilia; Spampinato, Concetto; Giordano, Daniela

    2012-11-01

    To investigate condylar symmetry and condyle fossa relationships in subjects with functional posterior crossbite comparing findings before and after rapid maxillary expansion (RME) treatment through low-dose computed tomography (CT). Twenty-six patients (14 girls and 12 boys, mean age 9.6 ± 1.4 years) with functional posterior crossbite (FPXB) diagnosis underwent rapid palatal expansion with a Hyrax appliance. Patients' temporomandibular joints (TMJ) underwent multislice CT scans before rapid palatal expansion (T0) and after (T1). Joint spaces were compared with those of a control sample of 13 subjects (7 girls and 5 boys, mean age 11 ± 0.6 years). Anterior space (AS), superior space (SS), and posterior space (PS) joint space measurements at T0 between the FPXB side and contralateral side demonstrated no statistically significant differences. After RME treatment (T1), all three joint spaces increased on both the FPXB side and the non-crossbite side. However, differences were statistically significant only for the SS when comparing the two sides at T1. SS increased more than AS and PS in the non-crossbite condyle (0.28 mm) and FPXB condyle (0.37 mm), and PS increased only on the FPXB side (0.34 mm). There were no statistically significant differences in condyle position within the glenoid fossa between the FPXB and non-crossbite side before treatment. Increases in joint spaces were observed after treatment with RME on both sides. These changes were, however, of small amounts.

  1. Laser Raman detection for oral cancer based on an adaptive Gaussian process classification method with posterior probabilities

    NASA Astrophysics Data System (ADS)

    Du, Zhanwei; Yang, Yongjian; Bai, Yuan; Wang, Lijun; Su, Le; Chen, Yong; Li, Xianchang; Zhou, Xiaodong; Jia, Jun; Shen, Aiguo; Hu, Jiming

    2013-03-01

    The existing methods for early and differential diagnosis of oral cancer are limited due to the unapparent early symptoms and the imperfect imaging examination methods. In this paper, the classification models of oral adenocarcinoma, carcinoma tissues and a control group with just four features are established by utilizing the hybrid Gaussian process (HGP) classification algorithm, with the introduction of the mechanisms of noise reduction and posterior probability. HGP shows much better performance in the experimental results. During the experimental process, oral tissues were divided into three groups, adenocarcinoma (n = 87), carcinoma (n = 100) and the control group (n = 134). The spectral data for these groups were collected. The prospective application of the proposed HGP classification method improved the diagnostic sensitivity to 56.35% and the specificity to about 70.00%, and resulted in a Matthews correlation coefficient (MCC) of 0.36. It is proved that the utilization of HGP in LRS detection analysis for the diagnosis of oral cancer gives accurate results. The prospect of application is also satisfactory.

  2. Effect of posterior crown margin placement on gingival health.

    PubMed

    Reitemeier, Bernd; Hänsel, Kristina; Walter, Michael H; Kastner, Christian; Toutenburg, Helge

    2002-02-01

    The clinical impact of posterior crown margin placement on gingival health has not been thoroughly quantified. This study evaluated the effect of posterior crown margin placement with multivariate analysis. Ten general dentists reviewed 240 patients with 480 metal-ceramic crowns in a prospective clinical trial. The alloy was randomly selected from 2 high gold, 1 low gold, and 1 palladium alloy. Variables were the alloy used, oral hygiene index score before treatment, location of crown margins at baseline, and plaque index and sulcus bleeding index scores recorded for restored and control teeth after 1 year. The effect of crown margin placement on sulcular bleeding and plaque accumulation was analyzed with regression models (P<.05). The probability of plaque at 1 year increased with increasing oral hygiene index score before treatment. The lingual surfaces demonstrated the highest probability of plaque. The risk of bleeding at intrasulcular posterior crown margins was approximately twice that at supragingival margins. Poor oral hygiene before treatment and plaque also were associated with sulcular bleeding. Facial sites exhibited a lower probability of sulcular bleeding than lingual surfaces. Type of alloy did not influence sulcular bleeding. In this study, placement of crown margins was one of several parameters that affected gingival health.

  3. Estimating the Probability of Traditional Copying, Conditional on Answer-Copying Statistics.

    PubMed

    Allen, Jeff; Ghattas, Andrew

    2016-06-01

    Statistics for detecting copying on multiple-choice tests produce p values measuring the probability of a value at least as large as that observed, under the null hypothesis of no copying. The posterior probability of copying is arguably more relevant than the p value, but cannot be derived from Bayes' theorem unless the population probability of copying and probability distribution of the answer-copying statistic under copying are known. In this article, the authors develop an estimator for the posterior probability of copying that is based on estimable quantities and can be used with any answer-copying statistic. The performance of the estimator is evaluated via simulation, and the authors demonstrate how to apply the formula using actual data. Potential uses, generalizability to other types of cheating, and limitations of the approach are discussed.

  4. Subtalar joint stress imaging with tomosynthesis.

    PubMed

    Teramoto, Atsushi; Watanabe, Kota; Takashima, Hiroyuki; Yamashita, Toshihiko

    2014-06-01

    The purpose of this study was to perform stress imaging of hindfoot inversion and eversion using tomosynthesis and to assess the subtalar joint range of motion (ROM) of healthy subjects. The subjects were 15 healthy volunteers with a mean age of 29.1 years. Coronal tomosynthesis stress imaging of the subtalar joint was performed in a total of 30 left and right ankles. A Telos stress device was used for the stress load, and the load was 150 N for both inversion and eversion. Tomographic images in which the posterior talocalcaneal joint could be confirmed on the neutral position images were used in measurements. The angle of the intersection formed by a line through the lateral articular facet of the posterior talocalcaneal joint and a line through the surface of the trochlea of the talus was measured. The mean change in the angle of the calcaneus with respect to the talus was 10.3 ± 4.8° with inversion stress and 5.0 ± 3.8° with eversion stress from the neutral position. The result was a clearer depiction of the subtalar joint, and inversion and eversion ROM of the subtalar joint was shown to be about 15° in healthy subjects. Diagnostic, Level IV.

  5. [Application of pie-crusting the medial collateral ligament release in arthroscopic surgery for posterior horn of 
medial meniscus in knee joint].

    PubMed

    Zhu, Weihong; Tang, Qi; Liao, Lele; Li, Ding; Yang, Yang; Chen, You

    2017-09-28

    To explore the effectiveness and safety of pie-crusting the medial collateral ligament release (MCL) in treating posterior horn of medial meniscus (PHMM) tear in tight medial tibiofemoral compartment of knee joint.
 Methods: Thirty-two consecutive patients with PHMM tear in tight medial tibiofemoral compartment of knee joint were admitted to our department from January, 2013 to December, 2014. All patients were performed pie-crusting the MCL release at its tibial insertion with 18-gauge intravenous needle. All patients were evaluated by valgus stress test and bilateral valgus stress radiograph at postoperative 1st day, 4th week and 12th week. Visual Analogue Scales (VAS), Lysholm scores, Tegner scores and International Knee Documentation Committee (IKDC) scores were recorded at the 1st, 3th, 6th month follow-up, then follow-up every 6 months.
 Results: The mean follow-up was 28 (24-36) months. All cases were negative in valgus stress test. MCL rupture, femoral fracture, articular cartilage lesion and neurovascular injury were not found at the last follow-up. The median medial joint space width of affected side and unaffected side for valgus stress radiographs were 6.8 mm and 4.3 mm (P<0.05) at the 1st day, 5.5 mm and 4.2 mm 
(P<0.05) in the 4th week and 4.8 mm and 4.3 mm (P>0.05) at the 12th week, respectively. VAS scores was changed from 4.5±1.5 preoperatively to 1.7±1.0 at the final follow-up (t=16.561, P<0.05). Lysholm scores was changed from 52.3±5.8 preoperatively to 93.2±6.3 at the final follow-up (t=-41.353, P<0.05). Tegner scores was changed from 4.1±1.1 preoperatively to 5.5±0.6 at the final follow-up (t=-18.792, P<0.05). IKDC scores was changed from 54.5±6.2 preoperative to 93.8±4.5 at the final follow-up (t=-38.253, P<0.05).
 Conclusion: Pie-crusting the medial collateral ligament release is a safe, minimal invasive and effective surgical option for posterior horn of medial meniscus tear in tight medial tibiofemoral compartment of knee

  6. A joint probability approach for coincidental flood frequency analysis at ungauged basin confluences

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Cheng

    2016-03-12

    A reliable and accurate flood frequency analysis at the confluence of streams is of importance. Given that long-term peak flow observations are often unavailable at tributary confluences, at a practical level, this paper presents a joint probability approach (JPA) to address the coincidental flood frequency analysis at the ungauged confluence of two streams based on the flow rate data from the upstream tributaries. One case study is performed for comparison against several traditional approaches, including the position-plotting formula, the univariate flood frequency analysis, and the National Flood Frequency Program developed by US Geological Survey. It shows that the results generatedmore » by the JPA approach agree well with the floods estimated by the plotting position and univariate flood frequency analysis based on the observation data.« less

  7. [Conditional probability analysis between tinnitus and comorbidities in patients attending the National Rehabilitation Institute-LGII in the period 2012-2013].

    PubMed

    Gómez Toledo, Verónica; Gutiérrez Farfán, Ileana; Verduzco-Mendoza, Antonio; Arch-Tirado, Emilio

    Tinnitus is defined as the conscious perception of a sensation of sound that occurs in the absence of an external stimulus. This audiological symptom affects 7% to 19% of the adult population. The aim of this study is to describe the associated comorbidities present in patients with tinnitus usingjoint and conditional probability analysis. Patients of both genders, diagnosed with unilateral or bilateral tinnitus, aged between 20 and 45 years, and had a full computerised medical record, were selected. Study groups were formed on the basis of the following clinical aspects: 1) audiological findings; 2) vestibular findings; 3) comorbidities such as, temporomandibular dysfunction, tubal dysfunction, otosclerosis and, 4) triggering factors of tinnitus noise exposure, respiratory tract infection, use of ototoxic and/or drugs. Of the patients with tinnitus, 27 (65%) reported hearing loss, 11 (26.19%) temporomandibular dysfunction, and 11 (26.19%) with vestibular disorders. When performing the joint probability analysis, it was found that the probability that a patient with tinnitus having hearing loss was 2742 0.65, and 2042 0.47 for bilateral type. The result for P (A ∩ B)=30%. Bayes' theorem P (AiB) = P(Ai∩B)P(B) was used, and various probabilities were calculated. Therefore, in patients with temporomandibulardysfunction and vestibular disorders, a posterior probability of P (Aі/B)=31.44% was calculated. Consideration should be given to the joint and conditional probability approach as tools for the study of different pathologies. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  8. A Case of Posterior Sternoclavicular Dislocation in a Professional American Football Player

    PubMed Central

    Yang, Justin S.; Bogunovic, Ljiljana; Brophy, Robert H.; Wright, Rick W.; Scott, Reggie; Matava, Matthew

    2015-01-01

    Sternoclavicular (SC) dislocation is a rare injury of the upper extremity. Treatment of posterior SC dislocation ranges from conservative (closed reduction) to operative (open reduction with or without surgical reconstruction of the SC joint). To date, we are unaware of any literature that exists pertaining to this injury or its treatment in elite athletes. The purpose of this case report is to describe a posterior SC joint dislocation in a professional American football player and to illustrate the issues associated with its diagnosis and treatment and the athlete’s return to sports. To our knowledge, this case is the first reported in a professional athlete. He was treated successfully with closed reduction and returned to play within 5 weeks of injury. PMID:26137177

  9. Force measurements in the medial meniscus posterior horn attachment: effects of anterior cruciate ligament removal.

    PubMed

    Markolf, Keith L; Jackson, Steven R; McAllister, David R

    2012-02-01

    Tears of the medial meniscus posterior horn attachment (PHA) occur clinically, and an anterior cruciate ligament (ACL)-deficient knee may be more vulnerable to this injury. The PHA forces from applied knee loadings will increase after removal of the ACL. Controlled laboratory study. A cap of bone containing the medial meniscus PHA was attached to a load cell that measured PHA tensile force. Posterior horn attachment forces were recorded before and after ACL removal during anteroposterior (AP) laxity testing at ±200 N and during passive knee extension tests with 5 N·m tibial torque and varus-valgus moment. Selected tests were also performed with 500 N joint load. For AP tests with no joint load, ACL removal increased laxity between 0° and 90° and increased PHA force generated by applied anterior tibial force between 30° and 90°. For AP tests with an intact ACL, application of joint load approximately doubled PHA forces. Anteroposterior testing of ACL-deficient knees was not possible with joint load because of bone cap failures from high PHA forces. Removal of the ACL during knee extension tests under joint load significantly increased PHA forces between 20° and 90° of flexion. For unloaded tests with applied tibial torque and varus-valgus moment, ACL removal had no significant effect on PHA forces. Applied anterior tibial force and external tibial torque were loading modes that produced relatively high PHA forces, presumably by impingement of the medial femoral condyle against the medial meniscus posterior horn rim. Under joint load, an ACL-deficient knee was particularly susceptible to PHA injury from applied anterior tibial force. Because tensile forces developed in the PHA are also borne by meniscus tissue near the attachment site, loading mechanisms that produce high PHA forces could also produce complete or partial radial tears near the posterior horn, a relatively common clinical observation.

  10. Lamb wave-based damage quantification and probability of detection modeling for fatigue life assessment of riveted lap joint

    NASA Astrophysics Data System (ADS)

    He, Jingjing; Wang, Dengjiang; Zhang, Weifang

    2015-03-01

    This study presents an experimental and modeling study for damage detection and quantification in riveted lap joints. Embedded lead zirconate titanate piezoelectric (PZT) ceramic wafer-type sensors are employed to perform in-situ non-destructive testing during fatigue cyclical loading. A multi-feature integration method is developed to quantify the crack size using signal features of correlation coefficient, amplitude change, and phase change. In addition, probability of detection (POD) model is constructed to quantify the reliability of the developed sizing method. Using the developed crack size quantification method and the resulting POD curve, probabilistic fatigue life prediction can be performed to provide comprehensive information for decision-making. The effectiveness of the overall methodology is demonstrated and validated using several aircraft lap joint specimens from different manufactures and under different loading conditions.

  11. Cadaveric Study of the Articular Branches of the Shoulder Joint.

    PubMed

    Eckmann, Maxim S; Bickelhaupt, Brittany; Fehl, Jacob; Benfield, Jonathan A; Curley, Jonathan; Rahimi, Ohmid; Nagpal, Ameet S

    This cadaveric study investigated the anatomic relationships of the articular branches of the suprascapular (SN), axillary (AN), and lateral pectoral nerves (LPN), which are potential targets for shoulder analgesia. Sixteen embalmed cadavers and 1 unembalmed cadaver, including 33 shoulders total, were dissected. Following dissections, fluoroscopic images were taken to propose an anatomical landmark to be used in shoulder articular branch blockade. Thirty-three shoulders from 17 total cadavers were studied. In a series of 16 shoulders, 16 (100%) of 16 had an intact SN branch innervating the posterior head of the humerus and shoulder capsule. Suprascapular sensory branches coursed laterally from the spinoglenoid notch then toward the glenohumeral joint capsule posteriorly. Axillary nerve articular branches innervated the posterolateral head of the humerus and shoulder capsule in the same 16 (100%) of 16 shoulders. The AN gave branches ascending circumferentially from the quadrangular space to the posterolateral humerus, deep to the deltoid, and inserting at the inferior portion of the posterior joint capsule. In 4 previously dissected and 17 distinct shoulders, intact LPNs could be identified in 14 (67%) of 21 specimens. Of these, 12 (86%) of 14 had articular branches innervating the anterior shoulder joint, and 14 (100%) of 14 LPN articular branches were adjacent to acromial branches of the thoracoacromial blood vessels over the superior aspect of the coracoid process. Articular branches from the SN, AN, and LPN were identified. Articular branches of the SN and AN insert into the capsule overlying the glenohumeral joint posteriorly. Articular branches of the LPN exist and innervate a portion of the anterior shoulder joint.

  12. The role of a small posterior malleolar fragment in trimalleolar fractures: a biomechanical study.

    PubMed

    Evers, J; Fischer, M; Zderic, I; Wähnert, D; Richards, R G; Gueorguiev, B; Raschke, M J; Ochman, S

    2018-01-01

    The aim of this study was to investigate the effect of a posterior malleolar fragment (PMF), with < 25% ankle joint surface, on pressure distribution and joint-stability. There is still little scientific evidence available to advise on the size of PMF, which is essential to provide treatment. To date, studies show inconsistent results and recommendations for surgical treatment date from 1940. A total of 12 cadaveric ankles were assigned to two study groups. A trimalleolar fracture was created, followed by open reduction and internal fixation. PMF was fixed in Group I, but not in Group II. Intra-articular pressure was measured and cyclic loading was performed. Contact area decreased following each fracture, while anatomical fixation restored it nearly to its intact level. Contact pressure decreased significantly with fixation of the PMF. In plantarflexion, the centre of force shifted significantly posteriorly in Group II and anteriorly in Group I. Load to failure testing showed no difference between the groups. Surgical reduction of a small PMF with less than 25% ankle joint surface improves pressure distribution but does not affect ankle joint stability. Cite this article: Bone Joint J 2018;100-B:95-100. ©2018 The British Editorial Society of Bone & Joint Surgery.

  13. Improving the Rank Precision of Population Health Measures for Small Areas with Longitudinal and Joint Outcome Models

    PubMed Central

    Athens, Jessica K.; Remington, Patrick L.; Gangnon, Ronald E.

    2015-01-01

    Objectives The University of Wisconsin Population Health Institute has published the County Health Rankings since 2010. These rankings use population-based data to highlight health outcomes and the multiple determinants of these outcomes and to encourage in-depth health assessment for all United States counties. A significant methodological limitation, however, is the uncertainty of rank estimates, particularly for small counties. To address this challenge, we explore the use of longitudinal and pooled outcome data in hierarchical Bayesian models to generate county ranks with greater precision. Methods In our models we used pooled outcome data for three measure groups: (1) Poor physical and poor mental health days; (2) percent of births with low birth weight and fair or poor health prevalence; and (3) age-specific mortality rates for nine age groups. We used the fixed and random effects components of these models to generate posterior samples of rates for each measure. We also used time-series data in longitudinal random effects models for age-specific mortality. Based on the posterior samples from these models, we estimate ranks and rank quartiles for each measure, as well as the probability of a county ranking in its assigned quartile. Rank quartile probabilities for univariate, joint outcome, and/or longitudinal models were compared to assess improvements in rank precision. Results The joint outcome model for poor physical and poor mental health days resulted in improved rank precision, as did the longitudinal model for age-specific mortality rates. Rank precision for low birth weight births and fair/poor health prevalence based on the univariate and joint outcome models were equivalent. Conclusion Incorporating longitudinal or pooled outcome data may improve rank certainty, depending on characteristics of the measures selected. For measures with different determinants, joint modeling neither improved nor degraded rank precision. This approach suggests a simple

  14. The non-Gaussian joint probability density function of slope and elevation for a nonlinear gravity wave field. [in ocean surface

    NASA Technical Reports Server (NTRS)

    Huang, N. E.; Long, S. R.; Bliven, L. F.; Tung, C.-C.

    1984-01-01

    On the basis of the mapping method developed by Huang et al. (1983), an analytic expression for the non-Gaussian joint probability density function of slope and elevation for nonlinear gravity waves is derived. Various conditional and marginal density functions are also obtained through the joint density function. The analytic results are compared with a series of carefully controlled laboratory observations, and good agreement is noted. Furthermore, the laboratory wind wave field observations indicate that the capillary or capillary-gravity waves may not be the dominant components in determining the total roughness of the wave field. Thus, the analytic results, though derived specifically for the gravity waves, may have more general applications.

  15. [Generalised Form of Synovial Chondromatosis of the Knee Joint].

    PubMed

    Vališ, P; Vyskočil, R

    2016-01-01

    This study describes a diagnostic and therapeutic algorithm in a 53-year-old male patient who was diagnosed with a synovial chondromatosis of the knee joint extending to the popliteal fossa and soft tissues around the knee. Because of the presence of massive nodules, the patient was indicated for total synovectomy, with removal of pathologically changed cartilaginous tissue, performed by combined anterior and posterior approaches to the knee joint. Despite complete removal of the synovium and loose cartilage bodies and the patient's pain relief in the post-operative time, three years after the operation new problems appeared. Magnetic resonance imaging (MRI) confirmed a relapse of synovial chondromatosis and the patient was indicated for revision surgery of the knee joint. The results of physical examination and MRI scans, and intra-operative findings in the patient are reported. synovial chondromatosis, total synovectomy, direct anterior and posterior approaches to the knee joint.

  16. Conarticular congruence of the hominoid subtalar joint complex with implications for joint function in Plio-Pleistocene hominins.

    PubMed

    Prang, Thomas C

    2016-07-01

    The purpose of this study is to test the hypothesis that conarticular surfaces areas and curvatures are correlates of mobility at the hominoid talocalcaneal and talonavicular joints. Articular surface areas and curvatures of the talonavicular, anterior talocalcaneal, and posterior talocalcaneal joints were quantified using a total of 425 three-dimensional surface models of extant hominoid and fossil hominin tali, calcanei, and naviculars. Quadric surface fitting was used to calculate curvatures, pairwise comparisons were used to evaluate statistical differences between taxa, and regression was used to test for the effects of allometry. Pairwise comparisons show that the distributions of values for joint curvature indices follow the predicted arboreal-terrestrial morphocline in hominoid primates with no effect of body mass (PGLS p > 0.05). OH 8 (Homo habilis) and LB 1 (Homo floresiensis) can be accommodated within the range of human variation for the talonavicular joint, whereas MH2 (Australopithecus sediba) falls within the ranges of variation for Pan troglodytes and Gorilla gorilla in measures of posterior talocalcaneal joint congruity. Joint curvature indices are better discriminators than joint surface area indices, which may reflect a greater contribution of rotation, rather than translation, to joint movement in plantigrade taxa due to discrepancies in conarticular congruence and the "convex-concave" rule. The pattern of joint congruence in Au. sediba contributes to other data on the foot and ankle suggesting that the lateral side of the foot was more mobile than the medial side, which is consistent with suggestions of increased medial weight transfer associated with hyperpronation. Am J Phys Anthropol 160:446-457, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Direct Posterior Bipolar Cervical Facet Radiofrequency Rhizotomy: A Simpler and Safer Approach to Denervate the Facet Capsule.

    PubMed

    Palea, Ovidiu; Andar, Haroon M; Lugo, Ramon; Granville, Michelle; Jacobson, Robert E

    2018-03-14

    Radiofrequency cervical rhizotomy has been shown to be effective for the relief of chronic neck pain, whether it be due to soft tissue injury, cervical spondylosis, or post-cervical spine surgery. The target and technique have traditionally been taught using an oblique approach to the anterior lateral capsule of the cervical facet joint. The goal is to position the electrode at the proximal location of the recurrent branch after it leaves the exiting nerve root and loops back to the cervical facet joint. The standard oblique approach to the recurrent nerve requires the testing of both motor and sensory components to verify the correct position and ensure safety so as to not damage the slightly more anterior nerve root. Bilateral lesions require the repositioning of the patient's neck. Poorly positioned electrodes can also pass anteriorly and contact the nerve root or vertebral artery. The direct posterior approach presented allows electrode positioning over a broader expanse of the facet joint without risk to the nerve root or vertebral artery. Over a four-year period, direct posterior radiofrequency ablation was performed under fluoroscopic guidance at multiple levels without neuro-stimulation testing with zero procedural neurologic events even as high as the C2 spinal segment. The direct posterior approach allows either unipolar or bipolar lesioning at multiple levels. Making a radiofrequency lesion along the larger posterior area of the facet capsule is as effective as the traditional target point closer to the nerve root but technically easier, allowing bilateral access and safety. The article will review the anatomy and innervation of the cervical facet joint and capsule, showing the diffuse nerve supply extending into the capsule of the facet joint that is more extensive than the recurrent medial sensory branches that have been the focus of radiofrequency lesioning.

  18. Direct Posterior Bipolar Cervical Facet Radiofrequency Rhizotomy: A Simpler and Safer Approach to Denervate the Facet Capsule

    PubMed Central

    Palea, Ovidiu; Andar, Haroon M; Lugo, Ramon; Jacobson, Robert E

    2018-01-01

    Radiofrequency cervical rhizotomy has been shown to be effective for the relief of chronic neck pain, whether it be due to soft tissue injury, cervical spondylosis, or post-cervical spine surgery. The target and technique have traditionally been taught using an oblique approach to the anterior lateral capsule of the cervical facet joint. The goal is to position the electrode at the proximal location of the recurrent branch after it leaves the exiting nerve root and loops back to the cervical facet joint. The standard oblique approach to the recurrent nerve requires the testing of both motor and sensory components to verify the correct position and ensure safety so as to not damage the slightly more anterior nerve root. Bilateral lesions require the repositioning of the patient's neck. Poorly positioned electrodes can also pass anteriorly and contact the nerve root or vertebral artery. The direct posterior approach presented allows electrode positioning over a broader expanse of the facet joint without risk to the nerve root or vertebral artery. Over a four-year period, direct posterior radiofrequency ablation was performed under fluoroscopic guidance at multiple levels without neuro-stimulation testing with zero procedural neurologic events even as high as the C2 spinal segment. The direct posterior approach allows either unipolar or bipolar lesioning at multiple levels. Making a radiofrequency lesion along the larger posterior area of the facet capsule is as effective as the traditional target point closer to the nerve root but technically easier, allowing bilateral access and safety. The article will review the anatomy and innervation of the cervical facet joint and capsule, showing the diffuse nerve supply extending into the capsule of the facet joint that is more extensive than the recurrent medial sensory branches that have been the focus of radiofrequency lesioning. PMID:29765790

  19. 97% accuracy of intra-articular glenohumeral injection with a modified (Delaware) posterior bone touch technique.

    PubMed

    Axe, Jeremie M; Axe, Michael J

    2013-10-01

    Unguided approaches have not demonstrated evidence of highly accurate intra-articular glenohumeral injections. The purpose of this study was to assess the accuracy of a posterior approach bone touch technique in conscious subjects without shoulder pathology as a first step in developing an accurate, reliable technique for use in patients. Twenty-six young subjects (age 22-26) without shoulder pathology (BMI 24 +/- 3), had bilateral shoulders injected while awake and seated. A 20 gauge 3.5-inch needle was introduced 1.5 cm below the scapular spine mid-way between the posterior lateral acromial corner and the posterior axillary crease. In Trial I, 20 shoulders were injected. After touching the humerus, the arm was oscillated. The needle advanced to 4-5 cm and 10 mL of dye injected. Pop and ease of flow were recorded. Immediate room change, spot fluoroscopy, and independent experienced radiology reading followed. In Trial II, 32 shoulders were injected. The technique was modified to touching the humerus, externally rotating the arm 25 degrees, and while remaining in bone contact, delivering 10 mL of dye. The same data as Trial I was recorded. In Trial I, 14/20 (70 percent) had dye within the glenohumeral joint. Five of seven failures were too anterior showing dye around the subscapularis muscle and all were associated with a pop. In Trial II, 31/32 (97 percent) had dye within glenohumeral joint. Twenty-three of 32 (72 percent) had a "pop," including the failure. Overall, 45/52 (87 percent) had dye within glenohumeral joint. Thirty-one of 52 (71 percent) of all shoulders had a "pop." Twenty-three of 52 (44 percent) shoulders had pain, resolving within 24 hours. A modified (Delaware) posterior bone touch technique for glenohumeral joint injection is 97 percent accurate in conscious healthy young subjects. Pop and ease of flow are not always indicative of correct needle placement. This study serves as an important first step in determining an optimum approach for

  20. Biomechanical consequences of a complete radial tear adjacent to the medial meniscus posterior root attachment site: in situ pull-out repair restores derangement of joint mechanics.

    PubMed

    Padalecki, Jeffrey R; Jansson, Kyle S; Smith, Sean D; Dornan, Grant J; Pierce, Casey M; Wijdicks, Coen A; Laprade, Robert F

    2014-03-01

    Complete radial tears near the medial meniscus posterior root attachment site disrupt the circumferential integrity of the meniscus (similar to a posterior root avulsion). These tears can compromise the circumferential integrity, and they have been reported in biomechanical studies to be comparable with the meniscectomized state. To quantify the tibiofemoral contact pressure and contact area changes that occur in cadaveric knees from complete posterior horn radial tears and subsequent repairs of the medial meniscus adjacent to the posterior root attachment site. Controlled laboratory study. Six nonpaired fresh-frozen human cadaveric knees each underwent 45 different testing conditions: 9 medial meniscus conditions (intact, root avulsion, root repair, serial radial tear at 3, 6, and 9 mm from the root attachment site, and in situ repair at the same 3 distances from the root attachment site) at 5 flexion angles (0°, 30°, 45°, 60°, and 90°), under a 1000-N axial load. Tekscan sensors were used to measure contact area and pressure in the medial and lateral compartments. The medial meniscus root avulsion and all radial tear conditions resulted in significantly decreased contact area and increased mean contact pressure compared with the intact state for knee flexion angles beyond 0° (P < .05). The root repair and in situ repairs restored contact area and pressure to levels statistically indistinguishable from those of the intact meniscus and increased contact area and decreased contact pressure compared with the corresponding tear conditions. Posterior horn radial tears adjacent to the medial meniscus root that extend to the meniscocapsular junction can lead to derangement of the loading profiles of the medial compartment that are similar to a root avulsion. Repair of these radial tears with an in situ pull-out technique restored joint mechanics to the intact state. Complete radial tears of the posterior horn of the medial meniscus, which occur relatively

  1. Features extraction in anterior and posterior cruciate ligaments analysis.

    PubMed

    Zarychta, P

    2015-12-01

    The main aim of this research is finding the feature vectors of the anterior and posterior cruciate ligaments (ACL and PCL). These feature vectors have to clearly define the ligaments structure and make it easier to diagnose them. Extraction of feature vectors is obtained by analysis of both anterior and posterior cruciate ligaments. This procedure is performed after the extraction process of both ligaments. In the first stage in order to reduce the area of analysis a region of interest including cruciate ligaments (CL) is outlined in order to reduce the area of analysis. In this case, the fuzzy C-means algorithm with median modification helping to reduce blurred edges has been implemented. After finding the region of interest (ROI), the fuzzy connectedness procedure is performed. This procedure permits to extract the anterior and posterior cruciate ligament structures. In the last stage, on the basis of the extracted anterior and posterior cruciate ligament structures, 3-dimensional models of the anterior and posterior cruciate ligament are built and the feature vectors created. This methodology has been implemented in MATLAB and tested on clinical T1-weighted magnetic resonance imaging (MRI) slices of the knee joint. The 3D display is based on the Visualization Toolkit (VTK). Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Intraoperative CT in the assessment of posterior wall acetabular fracture stability.

    PubMed

    Cunningham, Brian; Jackson, Kelly; Ortega, Gil

    2014-04-01

    Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images. Copyright 2014, SLACK Incorporated.

  3. Changes in temporomandibular joint spaces after arthroscopic disc repositioning: a self-control study

    PubMed Central

    Kai Hu, Ying; Abdelrehem, Ahmed; Yang, Chi; Cai, Xie Yi; Xie, Qian Yang; Sah, Manoj Kumar

    2017-01-01

    Disc repositioning is a common procedure for patients with anterior disc displacement (ADD). The purpose of this retrospective record-based study was to evaluate changes in the widths of joint spaces and condylar position changes in patients with unilateral ADD following arthroscopic disc repositioning, with the healthy sides as self-control, using magnetic resonance images (MRI).Widths of anterior, superior, and posterior joint spaces (AS, SS, and PS) were measured. The condylar position was described as anterior, centric or posterior, expressed as . Paired-t test and Chi-square test were used to analyze the data. Fifty-four records conformed to the inclusion criteria (mean age of 21.02 years). Widths of SS and PS increased significantly after surgery (P < 0.001) on the operative sides, while joint spaces of healthy sides and AS of operative sides had no significant changes. Dominant location of condyles of operative sides changed from a posterior position to an anterior position, while healthy sides were mostly centric condylar position no matter preoperatively or postoperatively. Therefore, the results of this study indicate that unilateral arthroscopic disc repositioning significantly increases the posterior and superior spaces of the affected joints, without affecting spaces of the healthy sides. PMID:28361905

  4. The Efficacy of Using Diagrams When Solving Probability Word Problems in College

    ERIC Educational Resources Information Center

    Beitzel, Brian D.; Staley, Richard K.

    2015-01-01

    Previous experiments have shown a deleterious effect of visual representations on college students' ability to solve total- and joint-probability word problems. The present experiments used conditional-probability problems, known to be more difficult than total- and joint-probability problems. The diagram group was instructed in how to use tree…

  5. Effects of Resection of Posterior Condyles of Femur on Extension Gap of Knee Joint in Total Knee Arthroplasty.

    PubMed

    Seo, Seung-Suk; Kim, Chang-Wan; Seo, Jin-Hyuk; Kim, Do-Hun; Kim, Ok-Gul; Lee, Chang-Rack

    2017-06-01

    When evaluating the effects of the preparation of the flexion gap on the extension gap in total knee arthroplasty (TKA), the effects of posterior condylar resection and osteophyte removal on the extension gap should be differentiated. Although the amount of osteophytes differs between patients, posterior condylar resection is a procedure that is routinely implemented in TKA. The aim of this study was to assess the effects of the resection of the posterior condyle of the femur on the extension gap in posterior-stabilized (PS) TKA. We enrolled 40 knees that underwent PS TKA between July 2010 and February 2011 with no or minimal osteophytes in the posterior compartment and a varus deformity of <15°. We measured the extension gap before and after the resection of the posterior condyle of the femur using a tensor under 20 and 40 lb of distraction force. Under 20 lb of distraction force, the average extension gap was 13.3 mm (standard deviation [SD], 1.6) before and 13.8 mm (SD, 1.6) after posterior condylar resection. Under 40 lb of distraction force, the average extension gap was 15.1 mm (SD, 1.5) before and 16.1 mm (SD, 1.7) after posterior condylar resection. The resection of the posterior condyle of the femur in PS TKA increased the extension gap. However, this increase was only by approximately 1 mm. In conclusion, posterior condylar resection does increase the extension gap by approximately 1 mm. However, in most case, this change in unlikely to be clinically important. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. [Efficacies of arthroscopic debridement and olecranon fossa plasty in the treatment of osteoarthritis and posterior elbow impingement].

    PubMed

    Liu, Yu-jie; Wang, Jun-liang; Li, Hai-feng; Qi, Wei; Wang, Ning

    2012-07-17

    To evaluate the efficacies of arthroscopic debridement and removal of osteophyma for olecroanon and olecranon fossa plasty for posterior impingement of elbow joint. Between 1999 and 2008, a total of 21 cases were diagnosed with osteoarthritis and posterior elbow impingement. There were 15 males and 6 females. And there were 16 right and 15 left cases. They included volleyball players (n = 7), tennis players (n = 7), golf enthusiasts (n = 4) and fencers (n = 3). The average duration of onset-operation was 3.5 years (range: 2.5 - 8). Arthroscopic exploration revealed synovial hyperplasia hypertrophy, cartilage degeneration and olecranon fossa hyperplasia with deformed olecranon fossa. Debridement and plasty were performed. Loose bodies were removed from elbow joint in 6 patients. Partial resection of posterior olecranon tip was performed and osteophytes or fibrous tissue removed in this area. Dynamic observation showed no posterior elbow impingement. Postoperative follow-up was conducted in 19 cases and 2 cases became lost to follow-up. The average follow-up period was 25.3 months (range: 18 - 42). All patients were evaluated preoperatively and postoperatively with the Hospital for Special Surgery Elbow Assessment Scale. The outcomes were excellent (n = 12), good (n = 7) and fair (n = 2). Postoperative patients elbow swelling and pain relieve, sports and life function returns to normal, elbow flexion and rotating mobility obviously improved. With the elbow radiological films to measure the range of motion, the average range of motion was 90.5° preoperatively and improved to 130° postoperatively. There was significant improvement in all cases. Posterior elbow impingement is caused by hyperextension trauma and elbow overuse during specific sporting activities. Arthroscopic debridement and olecroanon or olecranon fossa plasty demonstrates excellent results for posterior impingement of elbow joint.

  7. Joint Inference of Population Assignment and Demographic History

    PubMed Central

    Choi, Sang Chul; Hey, Jody

    2011-01-01

    A new approach to assigning individuals to populations using genetic data is described. Most existing methods work by maximizing Hardy–Weinberg and linkage equilibrium within populations, neither of which will apply for many demographic histories. By including a demographic model, within a likelihood framework based on coalescent theory, we can jointly study demographic history and population assignment. Genealogies and population assignments are sampled from a posterior distribution using a general isolation-with-migration model for multiple populations. A measure of partition distance between assignments facilitates not only the summary of a posterior sample of assignments, but also the estimation of the posterior density for the demographic history. It is shown that joint estimates of assignment and demographic history are possible, including estimation of population phylogeny for samples from three populations. The new method is compared to results of a widely used assignment method, using simulated and published empirical data sets. PMID:21775468

  8. Management of acromioclavicular joint injuries.

    PubMed

    Li, Xinning; Ma, Richard; Bedi, Asheesh; Dines, David M; Altchek, David W; Dines, Joshua S

    2014-01-01

    Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (≥type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these

  9. Biomechanical consequences of a tear of the posterior root of the medial meniscus. Surgical technique.

    PubMed

    Harner, Christopher D; Mauro, Craig S; Lesniak, Bryson P; Romanowski, James R

    2009-10-01

    Tears of the posterior root of the medial meniscus are becoming increasingly recognized. They can cause rapidly progressive arthritis, yet their biomechanical effects are not understood. The goal of this study was to determine the effects of posterior root tears of the medial meniscus and their repairs on tibiofemoral joint contact pressure and kinematics. Nine fresh-frozen cadaver knees were used. An axial load of 1000 N was applied with a custom testing jig at each of four knee-flexion angles: 0 degrees , 30 degrees , 60 degrees , and 90 degrees . The knees were otherwise unconstrained. Four conditions were tested: (1) intact, (2) a posterior root tear of the medial meniscus, (3) a repaired posterior root tear, and (4) a total medial meniscectomy. Fuji pressure-sensitive film was used to record the contact pressure and area for each testing condition. Kinematic data were obtained by using a robotic arm to record the position of the knees for each loading condition. Three-dimensional knee kinematics were analyzed with custom programs with use of previously described transformations. The measured variables were axial rotation, varus angulation, lateral translation, and anterior translation. In the medial compartment, a posterior root tear of the medial meniscus caused a 25% increase in peak contact pressure compared with that found in the intact condition (p < 0.001). Repair restored the peak contact pressure to normal. No difference was detected between the peak contact pressure after the total medial meniscectomy and that associated with the root tear. The peak contact pressure in the lateral compartment after the total medial meniscectomy was up to 13% greater than that for all other conditions (p = 0.026). Significant increases in external rotation and lateral tibial translation, compared with the values in the intact knee, were observed in association with the posterior root tear (2.98 degrees and 0.84 mm, respectively) and the meniscectomy (4.45 degrees and 0

  10. Rotational and translational stability of different methods for direct acromioclavicular ligament repair in anatomic acromioclavicular joint reconstruction.

    PubMed

    Beitzel, Knut; Obopilwe, Elifho; Apostolakos, John; Cote, Mark P; Russell, Ryan P; Charette, Ryan; Singh, Hardeep; Arciero, Robert A; Imhoff, Andreas B; Mazzocca, Augustus D

    2014-09-01

    Many reconstructions of acromioclavicular (AC) joint dislocations have focused on the coracoclavicular (CC) ligaments and neglected the functional contribution of the AC ligaments and the deltotrapezial fascia. To compare the modifications of previously published methods for direct AC reconstruction in addition to a CC reconstruction. The hypothesis was that there would be significant differences within the variations of surgical reconstructions. Controlled laboratory study. A total of 24 cadaveric shoulders were tested with a servohydraulic testing system. Two digitizing cameras evaluated the 3-dimensional movement. All reconstructions were based on a CC reconstruction using 2 clavicle tunnels and a tendon graft. The following techniques were used to reconstruct the AC ligaments: a graft was shuttled underneath the AC joint back from anterior and again sutured to the acromial side of the joint (group 1), a graft was fixed intramedullary in the acromion and distal clavicle (group 2), a graft was passed over the acromion and into an acromial tunnel (group 3), and a FiberTape was fixed in a cruciate configuration (group 4). Anterior, posterior, and superior translation, as well as anterior and posterior rotation, were tested. Group 1 showed significantly less posterior translation compared with the 3 other groups (P < .05) but did not show significant differences compared with the native joint. Groups 3 and 4 demonstrated significantly more posterior translation than the native joint. Group 1 showed significantly less anterior translation compared with groups 2 and 3. Group 3 demonstrated significantly more anterior translation than the native joint. Group 1 demonstrated significantly less superior translation compared with the other groups and with the native joint. The AC joint of group 1 was pulled apart less compared with all other reconstructions. Only group 1 reproduced the native joint for the anterior rotation at the posterior marker. Group 4 showed

  11. Posterior Predictive Checks for Conditional Independence between Response Time and Accuracy

    ERIC Educational Resources Information Center

    Bolsinova, Maria; Tijmstra, Jesper

    2016-01-01

    Conditional independence (CI) between response time and response accuracy is a fundamental assumption of many joint models for time and accuracy used in educational measurement. In this study, posterior predictive checks (PPCs) are proposed for testing this assumption. These PPCs are based on three discrepancy measures reflecting different…

  12. Independent events in elementary probability theory

    NASA Astrophysics Data System (ADS)

    Csenki, Attila

    2011-07-01

    In Probability and Statistics taught to mathematicians as a first introduction or to a non-mathematical audience, joint independence of events is introduced by requiring that the multiplication rule is satisfied. The following statement is usually tacitly assumed to hold (and, at best, intuitively motivated): If the n events E 1, E 2, … , E n are jointly independent then any two events A and B built in finitely many steps from two disjoint subsets of E 1, E 2, … , E n are also independent. The operations 'union', 'intersection' and 'complementation' are permitted only when forming the events A and B. Here we examine this statement from the point of view of elementary probability theory. The approach described here is accessible also to users of probability theory and is believed to be novel.

  13. Birth/birth-death processes and their computable transition probabilities with biological applications.

    PubMed

    Ho, Lam Si Tung; Xu, Jason; Crawford, Forrest W; Minin, Vladimir N; Suchard, Marc A

    2018-03-01

    Birth-death processes track the size of a univariate population, but many biological systems involve interaction between populations, necessitating models for two or more populations simultaneously. A lack of efficient methods for evaluating finite-time transition probabilities of bivariate processes, however, has restricted statistical inference in these models. Researchers rely on computationally expensive methods such as matrix exponentiation or Monte Carlo approximation, restricting likelihood-based inference to small systems, or indirect methods such as approximate Bayesian computation. In this paper, we introduce the birth/birth-death process, a tractable bivariate extension of the birth-death process, where rates are allowed to be nonlinear. We develop an efficient algorithm to calculate its transition probabilities using a continued fraction representation of their Laplace transforms. Next, we identify several exemplary models arising in molecular epidemiology, macro-parasite evolution, and infectious disease modeling that fall within this class, and demonstrate advantages of our proposed method over existing approaches to inference in these models. Notably, the ubiquitous stochastic susceptible-infectious-removed (SIR) model falls within this class, and we emphasize that computable transition probabilities newly enable direct inference of parameters in the SIR model. We also propose a very fast method for approximating the transition probabilities under the SIR model via a novel branching process simplification, and compare it to the continued fraction representation method with application to the 17th century plague in Eyam. Although the two methods produce similar maximum a posteriori estimates, the branching process approximation fails to capture the correlation structure in the joint posterior distribution.

  14. Joint Denoising/Compression of Image Contours via Shape Prior and Context Tree

    NASA Astrophysics Data System (ADS)

    Zheng, Amin; Cheung, Gene; Florencio, Dinei

    2018-07-01

    With the advent of depth sensing technologies, the extraction of object contours in images---a common and important pre-processing step for later higher-level computer vision tasks like object detection and human action recognition---has become easier. However, acquisition noise in captured depth images means that detected contours suffer from unavoidable errors. In this paper, we propose to jointly denoise and compress detected contours in an image for bandwidth-constrained transmission to a client, who can then carry out aforementioned application-specific tasks using the decoded contours as input. We first prove theoretically that in general a joint denoising / compression approach can outperform a separate two-stage approach that first denoises then encodes contours lossily. Adopting a joint approach, we first propose a burst error model that models typical errors encountered in an observed string y of directional edges. We then formulate a rate-constrained maximum a posteriori (MAP) problem that trades off the posterior probability p(x'|y) of an estimated string x' given y with its code rate R(x'). We design a dynamic programming (DP) algorithm that solves the posed problem optimally, and propose a compact context representation called total suffix tree (TST) that can reduce complexity of the algorithm dramatically. Experimental results show that our joint denoising / compression scheme outperformed a competing separate scheme in rate-distortion performance noticeably.

  15. Metrics and textural features of MRI diffusion to improve classification of pediatric posterior fossa tumors.

    PubMed

    Rodriguez Gutierrez, D; Awwad, A; Meijer, L; Manita, M; Jaspan, T; Dineen, R A; Grundy, R G; Auer, D P

    2014-05-01

    Qualitative radiologic MR imaging review affords limited differentiation among types of pediatric posterior fossa brain tumors and cannot detect histologic or molecular subtypes, which could help to stratify treatment. This study aimed to improve current posterior fossa discrimination of histologic tumor type by using support vector machine classifiers on quantitative MR imaging features. This retrospective study included preoperative MRI in 40 children with posterior fossa tumors (17 medulloblastomas, 16 pilocytic astrocytomas, and 7 ependymomas). Shape, histogram, and textural features were computed from contrast-enhanced T2WI and T1WI and diffusivity (ADC) maps. Combinations of features were used to train tumor-type-specific classifiers for medulloblastoma, pilocytic astrocytoma, and ependymoma types in separation and as a joint posterior fossa classifier. A tumor-subtype classifier was also produced for classic medulloblastoma. The performance of different classifiers was assessed and compared by using randomly selected subsets of training and test data. ADC histogram features (25th and 75th percentiles and skewness) yielded the best classification of tumor type (on average >95.8% of medulloblastomas, >96.9% of pilocytic astrocytomas, and >94.3% of ependymomas by using 8 training samples). The resulting joint posterior fossa classifier correctly assigned >91.4% of the posterior fossa tumors. For subtype classification, 89.4% of classic medulloblastomas were correctly classified on the basis of ADC texture features extracted from the Gray-Level Co-Occurence Matrix. Support vector machine-based classifiers using ADC histogram features yielded very good discrimination among pediatric posterior fossa tumor types, and ADC textural features show promise for further subtype discrimination. These findings suggest an added diagnostic value of quantitative feature analysis of diffusion MR imaging in pediatric neuro-oncology. © 2014 by American Journal of Neuroradiology.

  16. Ceramic joints

    DOEpatents

    Miller, Bradley J.; Patten, Jr., Donald O.

    1991-01-01

    Butt joints between materials having different coefficients of thermal expansion are prepared having a reduced probability of failure of stress facture. This is accomplished by narrowing/tapering the material having the lower coefficient of thermal expansion in a direction away from the joint interface and not joining the narrow-tapered surface to the material having the higher coefficient of thermal expansion.

  17. Posterior Cruciate Ligament Retention versus Posterior Stabilization for Total Knee Arthroplasty: A Meta-Analysis.

    PubMed

    Jiang, Chao; Liu, Zhenlei; Wang, Ying; Bian, Yanyan; Feng, Bin; Weng, Xisheng

    2016-01-01

    Although being debated for many years, the superiority of posterior cruciate-retaining (CR) total knee arthroplasty (TKA) and posterior-stabilized (PS) TKA remains controversial. We compare the knee scores, post-operative knee range of motion (ROM), radiological outcomes about knee kinematic and complications between CR TKA and PS TKA. Literature published up to August 2015 was searched in PubMed, Embase and Cochrane databases, and meta-analysis was performed using the software, Review Manager version 5.3. Totally 14 random control trials (RCTs) on this topic were included for the analysis, which showed that PS and CR TKA had no significant difference in Knee Society knee Score (KSS), pain score (KSPS), Hospital for Special Surgery score (HSS), kinematic characteristics including postoperative component alignment, tibial posterior slope and joint line, and complication rate. However, PS TKA is superior to CR TKA regarding post-operative knee range of motion (ROM) [Random Effect model (RE), Mean Difference (MD) = -7.07, 95% Confidential Interval (CI) -10.50 to -3.65, p<0.0001], improvement of ROM (Fixed Effect model (FE), MD = -5.66, 95% CI -10.79 to -0.53, p = 0.03) and femoral-tibial angle [FE, MD = 0.85, 95% CI 0.46 to 1.25, p<0.0001]. There are no clinically relevant differences between CR and PS TKA in terms of clinical, functional, radiological outcome, and complications, while PS TKA is superior to CR TKA in respects of ROM, while whether this superiority matters or not in clinical practice still needs further investigation and longer follow-up.

  18. Arthroscopic isolated posterior labral repair in rugby players

    PubMed Central

    Badge, Ravi; Tambe, Amol; Funk, Lennard

    2009-01-01

    Background The shoulder is the second most frequently injured joint after the knee in rugby players and labral tears appear to be common. There is limited data available in the literature regarding the mechanisms of posterior labral injury in rugby players and the management of these injuries. Objective The aim of this study is to report the clinical presentation, arthroscopic findings, surgical technique for repair, and the functional outcome in elite English rugby players with isolated posterior labral injuries. Study Design Case series (level IV evidence) Materials and Methods Over a 5-year period we surgically treated 142 elite rugby players, of whom 11 (7.8%) had isolated posterior labral injuries. All these 11 patients had significant contact injury. Only three (24%) patients had a true posterior shoulder dislocation. Pre- and postoperative assessment included Constant score, Oxford shoulder score, and Oxford instability score. We also assessed the time taken to return to preinjury level of fitness and the complications of surgery. Results Average follow-up was for 32 months (range 17–54 months). The mean Constant score improved from 66 to 99. The Oxford score indicated improvement, decreasing from 33 to 18; similarly, the Oxford instability score also decreased from 52.2 to 12.3. Return to playing rugby at peak level was at a mean of 4.3 months after arthroscopic repair. Conclusion Successful clinical results and rapid return to play can be achieved by appropriate early arthroscopic repair and supervised accelerated rehabilitation for posterior labral tears in elite rugby players. PMID:20616949

  19. Ultrasound Imaging and Guided Injection for the Lateral and Posterior Hip.

    PubMed

    Chang, Ke-Vin; Wu, Wei-Ting; Lew, Henry L; Özçakar, Levent

    2018-04-01

    Ultrasound has emerged as one of the most utilized tools to diagnose musculoskeletal disorders and to assist in interventions. Traditionally, sonographic examination of the hip joint has been challenging because most of the major structures are deeply situated, thus requiring the use of curvilinear transducer for better penetrance. The posterior lateral hip is a frequent area for musculoskeletal pain and nerve entrapments. Common disorders include greater trochanteric pain syndrome, gluteus medius tendinopathy, piriformis syndrome, pudendal neuralgia, and proximal hamstring tendinopathy. The present review article aims to delineate sonoanatomy of the posterior lateral hip and to exemplify several common ultrasound guided procedures at the greater trochanteric, gluteal, and ischial tuberosity regions.

  20. On probability-possibility transformations

    NASA Technical Reports Server (NTRS)

    Klir, George J.; Parviz, Behzad

    1992-01-01

    Several probability-possibility transformations are compared in terms of the closeness of preserving second-order properties. The comparison is based on experimental results obtained by computer simulation. Two second-order properties are involved in this study: noninteraction of two distributions and projections of a joint distribution.

  1. Sacroiliac Joint Fusion Using Triangular Titanium Implants vs. Non-Surgical Management: Six-Month Outcomes from a Prospective Randomized Controlled Trial.

    PubMed

    Whang, Peter; Cher, Daniel; Polly, David; Frank, Clay; Lockstadt, Harry; Glaser, John; Limoni, Robert; Sembrano, Jonathan

    2015-01-01

    Sacroiliac (SI) joint pain is a prevalent, underdiagnosed cause of lower back pain. SI joint fusion can relieve pain and improve quality of life in patients who have failed nonoperative care. To date, no study has concurrently compared surgical and non-surgical treatments for chronic SI joint dysfunction. We conducted a prospective randomized controlled trial of 148 subjects with SI joint dysfunction due to degenerative sacroiliitis or sacroiliac joint disruptions who were assigned to either minimally invasive SI joint fusion with triangular titanium implants (N=102) or non-surgical management (NSM, n=46). SI joint pain scores, Oswestry Disability Index (ODI), Short-Form 36 (SF-36) and EuroQol-5D (EQ-5D) were collected at baseline and at 1, 3 and 6 months after treatment commencement. Six-month success rates, defined as the proportion of treated subjects with a 20-mm improvement in SI joint pain in the absence of severe device-related or neurologic SI joint-related adverse events or surgical revision, were compared using Bayesian methods. Subjects (mean age 51, 70% women) were highly debilitated at baseline (mean SI joint VAS pain score 82, mean ODI score 62). Six-month follow-up was obtained in 97.3%. By 6 months, success rates were 81.4% in the surgical group vs. 23.9% in the NSM group (difference of 56.6%, 95% posterior credible interval 41.4-70.0%, posterior probability of superiority >0.999). Clinically important (≥15 point) ODI improvement at 6 months occurred in 75% of surgery subjects vs. 27.3% of NSM subjects. At six months, quality of life improved more in the surgery group and satisfaction rates were high. The mean number of adverse events in the first six months was slightly higher in the surgical group compared to the non-surgical group (1.3 vs. 1.0 events per subject, p=0.1857). Six-month follow-up from this level 1 study showed that minimally invasive SI joint fusion using triangular titanium implants was more effective than non-surgical management

  2. Sacroiliac Joint Fusion Using Triangular Titanium Implants vs. Non-Surgical Management: Six-Month Outcomes from a Prospective Randomized Controlled Trial

    PubMed Central

    Whang, Peter; Polly, David; Frank, Clay; Lockstadt, Harry; Glaser, John; Limoni, Robert; Sembrano, Jonathan

    2015-01-01

    Background Sacroiliac (SI) joint pain is a prevalent, underdiagnosed cause of lower back pain. SI joint fusion can relieve pain and improve quality of life in patients who have failed nonoperative care. To date, no study has concurrently compared surgical and non-surgical treatments for chronic SI joint dysfunction. Methods We conducted a prospective randomized controlled trial of 148 subjects with SI joint dysfunction due to degenerative sacroiliitis or sacroiliac joint disruptions who were assigned to either minimally invasive SI joint fusion with triangular titanium implants (N=102) or non-surgical management (NSM, n=46). SI joint pain scores, Oswestry Disability Index (ODI), Short-Form 36 (SF-36) and EuroQol-5D (EQ-5D) were collected at baseline and at 1, 3 and 6 months after treatment commencement. Six-month success rates, defined as the proportion of treated subjects with a 20-mm improvement in SI joint pain in the absence of severe device-related or neurologic SI joint-related adverse events or surgical revision, were compared using Bayesian methods. Results Subjects (mean age 51, 70% women) were highly debilitated at baseline (mean SI joint VAS pain score 82, mean ODI score 62). Six-month follow-up was obtained in 97.3%. By 6 months, success rates were 81.4% in the surgical group vs. 23.9% in the NSM group (difference of 56.6%, 95% posterior credible interval 41.4-70.0%, posterior probability of superiority >0.999). Clinically important (≥15 point) ODI improvement at 6 months occurred in 75% of surgery subjects vs. 27.3% of NSM subjects. At six months, quality of life improved more in the surgery group and satisfaction rates were high. The mean number of adverse events in the first six months was slightly higher in the surgical group compared to the non-surgical group (1.3 vs. 1.0 events per subject, p=0.1857). Conclusions Six-month follow-up from this level 1 study showed that minimally invasive SI joint fusion using triangular titanium implants was more

  3. Development of a program for toric intraocular lens calculation considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and effective lens position.

    PubMed

    Eom, Youngsub; Ryu, Dongok; Kim, Dae Wook; Yang, Seul Ki; Song, Jong Suk; Kim, Sug-Whan; Kim, Hyo Myung

    2016-10-01

    To evaluate the toric intraocular lens (IOL) calculation considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and effective lens position (ELP). Two thousand samples of corneal parameters with keratometric astigmatism ≥ 1.0 D were obtained using bootstrap methods. The probability distributions for incision-induced keratometric and posterior corneal astigmatisms, as well as ELP were estimated from the literature review. The predicted residual astigmatism error using method D with an IOL add power calculator (IAPC) was compared with those derived using methods A, B, and C through Monte-Carlo simulation. Method A considered the keratometric astigmatism and incision-induced keratometric astigmatism, method B considered posterior corneal astigmatism in addition to the A method, method C considered incision-induced posterior corneal astigmatism in addition to the B method, and method D considered ELP in addition to the C method. To verify the IAPC used in this study, the predicted toric IOL cylinder power and its axis using the IAPC were compared with ray-tracing simulation results. The median magnitude of the predicted residual astigmatism error using method D (0.25 diopters [D]) was smaller than that derived using methods A (0.42 D), B (0.38 D), and C (0.28 D) respectively. Linear regression analysis indicated that the predicted toric IOL cylinder power and its axis had excellent goodness-of-fit between the IAPC and ray-tracing simulation. The IAPC is a simple but accurate method for predicting the toric IOL cylinder power and its axis considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and ELP.

  4. Biomechanical consequences of a tear of the posterior root of the medial meniscus. Similar to total meniscectomy.

    PubMed

    Allaire, Robert; Muriuki, Muturi; Gilbertson, Lars; Harner, Christopher D

    2008-09-01

    Tears of the posterior root of the medial meniscus are becoming increasingly recognized. They can cause rapidly progressive arthritis, yet their biomechanical effects are not understood. The goal of this study was to determine the effects of posterior root tears of the medial meniscus and their repairs on tibiofemoral joint contact pressure and kinematics. Nine fresh-frozen cadaver knees were used. An axial load of 1000 N was applied with a custom testing jig at each of four knee-flexion angles: 0 degrees, 30 degrees, 60 degrees, and 90 degrees. The knees were otherwise unconstrained. Four conditions were tested: (1) intact, (2) a posterior root tear of the medial meniscus, (3) a repaired posterior root tear, and (4) a total medial meniscectomy. Fuji pressure-sensitive film was used to record the contact pressure and area for each testing condition. Kinematic data were obtained by using a robotic arm to record the position of the knees for each loading condition. Three-dimensional knee kinematics were analyzed with custom programs with use of previously described transformations. The measured variables were axial rotation, varus angulation, lateral translation, and anterior translation. In the medial compartment, a posterior root tear of the medial meniscus caused a 25% increase in peak contact pressure compared with that found in the intact condition (p < 0.001). Repair restored the peak contact pressure to normal. No difference was detected between the peak contact pressure after the total medial meniscectomy and that associated with the root tear. The peak contact pressure in the lateral compartment after the total medial meniscectomy was up to 13% greater than that for all other conditions (p = 0.026). Significant increases in external rotation and lateral tibial translation, compared with the values in the intact knee, were observed in association with the posterior root tear (2.98 degrees and 0.84 mm, respectively) and the meniscectomy (4.45 degrees and 0

  5. Percutaneous CT-guided sacroiliac joint sampling for infection: aspiration, biopsy, and technique.

    PubMed

    Knipp, David; Simeone, F Joseph; Nelson, Sandra B; Huang, Ambrose J; Chang, Connie Y

    2018-04-01

    To evaluate methods of CT-guided sacroiliac joint sampling in patients with suspected infection. All CT-guided sacroiliac joint sampling procedures for suspected infection were reviewed for sampling type (aspiration, lavage aspiration, biopsy), microbiology results, and clinical and imaging follow-up. The primary gold standard was anatomic pathology. If pathology was not available, then positive blood culture with the same organism as SIJ sampling, imaging and clinical follow-up, or clinical follow-up only were used. Anterior and posterior joint distention was evaluated by MRI within 7 days of the procedure. A total of 34 patients (age 39 ± 20 (range, 6-75) years; 21 F, 13 M) were included. Aspiration samples only were obtained in 13/34 (38%) cases, biopsy samples only in 9/34 (26%) cases, and both samples in 12/34 (35%) cases. There was an overall 54% sensitivity and 86% specificity. For the aspiration samples, sensitivity and specificity were 60 and 81%, respectively, compared to 45 and 90% for the biopsy samples. In cases with both samples, biopsy did not add additional microbial information. Seventeen (17/34, 50%) patients had an MRI. The anterior joint was more distended than the posterior joint in 15/17 (88%) of patients, and this difference was significant (P = 0.0003). All of these 17 patients had an attempted aspiration by a posterior approach; 6/17 (35%) resulted in a successful aspiration. Aspiration of the sacroiliac joint has a higher sensitivity than biopsy and should always be attempted first. MRI may be helpful for procedure planning.

  6. Bayesian operational modal analysis with asynchronous data, Part II: Posterior uncertainty

    NASA Astrophysics Data System (ADS)

    Zhu, Yi-Chen; Au, Siu-Kui

    2018-01-01

    A Bayesian modal identification method has been proposed in the companion paper that allows the most probable values of modal parameters to be determined using asynchronous ambient vibration data. This paper investigates the identification uncertainty of modal parameters in terms of their posterior covariance matrix. Computational issues are addressed. Analytical expressions are derived to allow the posterior covariance matrix to be evaluated accurately and efficiently. Synthetic, laboratory and field data examples are presented to verify the consistency, investigate potential modelling error and demonstrate practical applications.

  7. Posterior medial meniscus detachment: a unique type of medial meniscal tear.

    PubMed

    Rubinstein, Richard A; DeHaan, Alex; Baldwin, James L

    2009-10-01

    Patients with posterior medial meniscal detachment, as determined at knee arthroscopy, were evaluated retrospectively. Mean follow-up was 5.3 years for 8 men and 20 women (30 knees; mean age, 57 years). Most patients had acute onset of pain with a minor specific incident. Seventeen patients were obese, 9 were overweight, and 2 were normal. Eleven of 22 magnetic resonance imaging evaluations detected a tear at the site of the posterior medial meniscus root. Nine of 16 bone scan evaluations showed moderate uptake medially. Arthroscopic treatment included partial medial meniscectomy or meniscal repair. Twelve knees (40%) showed significant progression of arthritis. Of the 7 patients with severe arthritic knees, 5 have subsequently undergone total knee arthroplasty, 1 is considering total knee arthroplasty, and the other has minimal symptoms. Patients should be counseled about the clinical course of posterior medial meniscus detachment and its potential for progressive arthritis in the joint.

  8. Effects of Wii balance board exercises on balance after posterior cruciate ligament reconstruction.

    PubMed

    Puh, Urška; Majcen, Nia; Hlebš, Sonja; Rugelj, Darja

    2014-05-01

    To establish the effects of training on Wii balance board (WBB) after posterior cruciate ligament (PCL) reconstruction on balance. Included patient injured her posterior cruciate ligament 22 months prior to the study. Training on WBB was performed 4 weeks, 6 times per week, 30-45 min per day. Center of pressure (CoP) sway during parallel and one-leg stance, and body weight distribution in parallel stance were measured. Additionally, measurements of joint range of motion and limb circumferences were taken before and after training. After training, the body weight was almost equally distributed on both legs. Decrease in CoP sway was most significant for one-leg stance with each leg on compliant surface with eyes open and closed. The knee joint range of motion increased and limb circumferences decreased. According to the results of this single case report, we might recommend the use of WBB for balance training after PCL reconstruction. Case series with no comparison group, Level IV.

  9. The relationship between species detection probability and local extinction probability

    USGS Publications Warehouse

    Alpizar-Jara, R.; Nichols, J.D.; Hines, J.E.; Sauer, J.R.; Pollock, K.H.; Rosenberry, C.S.

    2004-01-01

    In community-level ecological studies, generally not all species present in sampled areas are detected. Many authors have proposed the use of estimation methods that allow detection probabilities that are < 1 and that are heterogeneous among species. These methods can also be used to estimate community-dynamic parameters such as species local extinction probability and turnover rates (Nichols et al. Ecol Appl 8:1213-1225; Conserv Biol 12:1390-1398). Here, we present an ad hoc approach to estimating community-level vital rates in the presence of joint heterogeneity of detection probabilities and vital rates. The method consists of partitioning the number of species into two groups using the detection frequencies and then estimating vital rates (e.g., local extinction probabilities) for each group. Estimators from each group are combined in a weighted estimator of vital rates that accounts for the effect of heterogeneity. Using data from the North American Breeding Bird Survey, we computed such estimates and tested the hypothesis that detection probabilities and local extinction probabilities were negatively related. Our analyses support the hypothesis that species detection probability covaries negatively with local probability of extinction and turnover rates. A simulation study was conducted to assess the performance of vital parameter estimators as well as other estimators relevant to questions about heterogeneity, such as coefficient of variation of detection probabilities and proportion of species in each group. Both the weighted estimator suggested in this paper and the original unweighted estimator for local extinction probability performed fairly well and provided no basis for preferring one to the other.

  10. Multinomial mixture model with heterogeneous classification probabilities

    USGS Publications Warehouse

    Holland, M.D.; Gray, B.R.

    2011-01-01

    Royle and Link (Ecology 86(9):2505-2512, 2005) proposed an analytical method that allowed estimation of multinomial distribution parameters and classification probabilities from categorical data measured with error. While useful, we demonstrate algebraically and by simulations that this method yields biased multinomial parameter estimates when the probabilities of correct category classifications vary among sampling units. We address this shortcoming by treating these probabilities as logit-normal random variables within a Bayesian framework. We use Markov chain Monte Carlo to compute Bayes estimates from a simulated sample from the posterior distribution. Based on simulations, this elaborated Royle-Link model yields nearly unbiased estimates of multinomial and correct classification probability estimates when classification probabilities are allowed to vary according to the normal distribution on the logit scale or according to the Beta distribution. The method is illustrated using categorical submersed aquatic vegetation data. ?? 2010 Springer Science+Business Media, LLC.

  11. Bivariate categorical data analysis using normal linear conditional multinomial probability model.

    PubMed

    Sun, Bingrui; Sutradhar, Brajendra

    2015-02-10

    Bivariate multinomial data such as the left and right eyes retinopathy status data are analyzed either by using a joint bivariate probability model or by exploiting certain odds ratio-based association models. However, the joint bivariate probability model yields marginal probabilities, which are complicated functions of marginal and association parameters for both variables, and the odds ratio-based association model treats the odds ratios involved in the joint probabilities as 'working' parameters, which are consequently estimated through certain arbitrary 'working' regression models. Also, this later odds ratio-based model does not provide any easy interpretations of the correlations between two categorical variables. On the basis of pre-specified marginal probabilities, in this paper, we develop a bivariate normal type linear conditional multinomial probability model to understand the correlations between two categorical variables. The parameters involved in the model are consistently estimated using the optimal likelihood and generalized quasi-likelihood approaches. The proposed model and the inferences are illustrated through an intensive simulation study as well as an analysis of the well-known Wisconsin Diabetic Retinopathy status data. Copyright © 2014 John Wiley & Sons, Ltd.

  12. Asymptotic approximations to posterior distributions via conditional moment equations

    USGS Publications Warehouse

    Yee, J.L.; Johnson, W.O.; Samaniego, F.J.

    2002-01-01

    We consider asymptotic approximations to joint posterior distributions in situations where the full conditional distributions referred to in Gibbs sampling are asymptotically normal. Our development focuses on problems where data augmentation facilitates simpler calculations, but results hold more generally. Asymptotic mean vectors are obtained as simultaneous solutions to fixed point equations that arise naturally in the development. Asymptotic covariance matrices flow naturally from the work of Arnold & Press (1989) and involve the conditional asymptotic covariance matrices and first derivative matrices for conditional mean functions. When the fixed point equations admit an analytical solution, explicit formulae are subsequently obtained for the covariance structure of the joint limiting distribution, which may shed light on the use of the given statistical model. Two illustrations are given. ?? 2002 Biometrika Trust.

  13. Bayesian seismic inversion based on rock-physics prior modeling for the joint estimation of acoustic impedance, porosity and lithofacies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Passos de Figueiredo, Leandro, E-mail: leandrop.fgr@gmail.com; Grana, Dario; Santos, Marcio

    We propose a Bayesian approach for seismic inversion to estimate acoustic impedance, porosity and lithofacies within the reservoir conditioned to post-stack seismic and well data. The link between elastic and petrophysical properties is given by a joint prior distribution for the logarithm of impedance and porosity, based on a rock-physics model. The well conditioning is performed through a background model obtained by well log interpolation. Two different approaches are presented: in the first approach, the prior is defined by a single Gaussian distribution, whereas in the second approach it is defined by a Gaussian mixture to represent the well datamore » multimodal distribution and link the Gaussian components to different geological lithofacies. The forward model is based on a linearized convolutional model. For the single Gaussian case, we obtain an analytical expression for the posterior distribution, resulting in a fast algorithm to compute the solution of the inverse problem, i.e. the posterior distribution of acoustic impedance and porosity as well as the facies probability given the observed data. For the Gaussian mixture prior, it is not possible to obtain the distributions analytically, hence we propose a Gibbs algorithm to perform the posterior sampling and obtain several reservoir model realizations, allowing an uncertainty analysis of the estimated properties and lithofacies. Both methodologies are applied to a real seismic dataset with three wells to obtain 3D models of acoustic impedance, porosity and lithofacies. The methodologies are validated through a blind well test and compared to a standard Bayesian inversion approach. Using the probability of the reservoir lithofacies, we also compute a 3D isosurface probability model of the main oil reservoir in the studied field.« less

  14. The Relationship Between Osteoarthritis of the Lumbar Facet Joints and Lumbosacropelvic Morphology.

    PubMed

    Sahin, Mehmet Sukru; Ergün, Adviye; Aslan, Akın

    2015-10-01

    Cross-sectional study. To investigate the relation between lumbosacropelvic morphology and the presence and degree of facet joint degeneration. Osteoarthritis of the facet joints is one of the most common degenerative changes in the spine. It is considered to be formed secondary to repetitive stress or trauma and spinal deformity with secondary overload. The cause(s) of facet joints osteoarthritis, however, have not been clearly identified. Abdominal computed tomography (CT) images of 723 patients which were taken between the years 2010 and 2014 were evaluated retrospectively. Patients with prior lumbar spinal surgery, serious congenital anomalies on CT, incomplete or complete lumbosacral transition, severe scoliosis, were excluded from the study. To eliminate the age- and sex-related differences in spinopelvic morphology, a study group was formed of the remaining subjects by including patients from a specific age group (30-35 yr) and same sex (females). For each patient the presence and grade of facet joint degeneration was investigated. In addition, pelvic incidence (PI), sacral slope and the angles of L1-L5 lumbar lordosis, sacral table, L5 vertebra posterior, and sacral kyphosis were measured for each patient. Sacral slope, sacral kyphosis, and L1-L5 lumbar lordosis angle were significantly higher in patients with osteoarthritic compared with normal subjects (P = 0.015, P = 0.018, P = 0.016). L5 vertebra posterior and sacral table angle were found to be significantly lower in patients with osteoarthritic than in normal subjects (P = 0.019, P = 0.007). The degree of facet joint degeneration was noticed to increase parallel to the decrease in the sacral table angle and L5 vertebra posterior angle, and to the increase in the L1-L5 lumbar lordosis, PI, and sacral slope. A close relation exists between the presence and degree of degeneration in the facet joint and lumbosacral pelvic morphology. Prevalence and degree of the degeneration in facet joint increases as

  15. A 3D finite element model to investigate prosthetic interface stresses of different posterior tibial slope.

    PubMed

    Shen, Yi; Li, Xiaomiao; Fu, Xiaodong; Wang, Weili

    2015-11-01

    Posterior tibial slope that is created during proximal tibial resection in total knee arthroplasty has emerged as an important factor in the mechanics of the knee joint and the surgical outcome. But the ideal degree of posterior tibial slope for recovery of the knee joint function and preventions of complications remains controversial and should vary in different racial groups. The objective of this paper is to investigate the effects of posterior tibial slope on contact stresses in the tibial polyethylene component of total knee prostheses. Three-dimensional finite element analysis was used to calculate contact stresses in tibial polyethylene component of total knee prostheses subjected to a compressive load. The 3D finite element model of total knee prosthesis was constructed from the images produced by 3D scanning technology. Stresses in tibial polyethylene component were calculated with four different posterior tibial slopes (0°, 3°, 6° and 9°). The 3D finite element model of total knee prosthesis we presented was well validated. We found that the stress distribution in the polythene as evaluated by the distributions of the von Mises stress, the maximum principle stress, the minimum principle stress and the Cpress were more uniform with 3° and 6° posterior tibial slopes than with 0° and 9° posterior tibial slopes. Moreover, the peaks of the above stresses and trends of changes with increasing degree of knee flexion were more ideal with 3° and 6° posterior slopes. The results suggested that the tibial component inclination might be favourable to 7°-10° so far as the stress distribution is concerned. The range of the tibial component inclination also can decrease the wear of polyethylene. Chinese posterior tibial slope is bigger than in the West, and the current domestic use of prostheses is imported from the West, so their demands to tilt back bone cutting can lead to shorten the service life of prostheses; this experiment result is of important

  16. Arthroscopic management of posterior instability: evolution of technique and results.

    PubMed

    Savoie, Felix H; Holt, M Shaun; Field, Larry D; Ramsey, J Randall

    2008-04-01

    The purpose of this study was to evaluate the effectiveness of arthroscopic posterior shoulder reconstruction. We treated 136 shoulders in 131 patients with a diagnosis of primary posterior instability who failed 6 months of vigorous rehabilitation by operative stabilization between 1989 and 2001. Inclusion criterion was primary posterior instability that failed an extensive rehabilitative program with functional impairment and pain. Exclusion criterion was less than 12 months of follow-up and Suretac (Smith & Nephew, Andover, MA) or laser stabilization, leaving 92 shoulders in 90 patients available for the study (69 male, 21 female). Follow-up ranged from 12 to 132 months (average, 28 months). Each patient underwent diagnostic arthroscopy and surgical repair at the same time using one of several primary procedures. The procedure used was based on the pathologic entity noted at the time of surgery. At an average follow-up of 28 months, 97% of the shoulders were stable and considered a success based on the Neer-Foster rating scale. Posterior pathology varied, and a reverse Bankart lesion alone was found 51% of the time, a stretched posterior capsule 67% of the time, and a combination of a reverse Bankart lesion and capsular stretching 16% of the time. The rotator interval was obviously damaged in 61% of cases. Multiple accompanying lesions were found, including anterior-superior labral tears and SLAP tears (20%), superior glenohumeral ligament injury (7%), middle glenohumeral ligament injury (38%), anteroinferior glenohumaral ligament injury (37%), and an enlarged axillary pouch (20%). No essential lesion is present for posterior instability. Multiple varied pathologies will be present in a shoulder presenting with posterior instability. Arthroscopic surgery allows inspection of the joint and anatomic-specific repairs based on pathology. Careful attention to all the supporting structures of the shoulder, including the rotator interval, the anterior-superior labrum

  17. Digital map of posterior cerebral artery infarcts associated with posterior cerebral artery trunk and branch occlusion.

    PubMed

    Phan, Thanh G; Fong, Ashley C; Donnan, Geoffrey; Reutens, David C

    2007-06-01

    Knowledge of the extent and distribution of infarcts of the posterior cerebral artery (PCA) may give insight into the limits of the arterial territory and infarct mechanism. We describe the creation of a digital atlas of PCA infarcts associated with PCA branch and trunk occlusion by magnetic resonance imaging techniques. Infarcts were manually segmented on T(2)-weighted magnetic resonance images obtained >24 hours after stroke onset. The images were linearly registered into a common stereotaxic coordinate space. The segmented images were averaged to yield the probability of involvement by infarction at each voxel. Comparisons were made with existing maps of the PCA territory. Thirty patients with a median age of 61 years (range, 22 to 86 years) were studied. In the digital atlas of the PCA, the highest frequency of infarction was within the medial temporal lobe and lingual gyrus (probability=0.60 to 0.70). The mean and maximal PCA infarct volumes were 55.1 and 128.9 cm(3), respectively. Comparison with published maps showed greater agreement in the anterior and medial boundaries of the PCA territory compared with its posterior and lateral boundaries. We have created a probabilistic digital atlas of the PCA based on subacute magnetic resonance scans. This approach is useful for establishing the spatial distribution of strokes in a given cerebral arterial territory and determining the regions within the arterial territory that are at greatest risk of infarction.

  18. Posterior root tear fixation of the lateral meniscus combined with arthroscopic ACL double-bundle reconstruction: technical note of a transosseous fixation using the tibial PL tunnel.

    PubMed

    Forkel, Philipp; Petersen, Wolf

    2012-03-01

    According to our observation in ACL reconstruction, we find root tears of the posterior horn of the lateral meniscus as a common concomitant injury in ACL-deficient knees. This might be a consequence of initial trauma or of the increased anterior-posterior translation of the tibia and an overload impact on the posterior meniscus root in ACL-deficient knees. A tear of the posterior horn of the medial meniscus causes a 25% increase in peak pressure in the medial compartment compared with that found in the intact condition. The repair restores the peak contact pressure to normal (Allaire et al. in J Bone Joint Surg Am 90(9):1922-1931, [2008]). A tear of the posterior horn of the lateral meniscus might have similar consequences. We hypothesize the surgical anatomical reattachment of the root at the tibia helping to restore knee joint kinematics and helping to advance ACL-graft function. This article presents an arthroscopical technique to reattach the posterior meniscus root in combination with ACL double-bundle reconstruction. The procedure uses the tibial PL tunnel to fix the meniscus suture.

  19. Posterior capsular fibrosis in professional baseball pitchers: case series of MR arthrographic findings in six patients with glenohumeral internal rotational deficit.

    PubMed

    Tehranzadeh, Arash D; Fronek, Jan; Resnick, Donald

    2007-01-01

    In the high-performance athlete, acquired thickening of the posterior joint capsule is a proposed etiology for glenohumeral internal rotational deficit (GIRD). The purpose of this study was to present our MR arthrographic imaging observations of posterior capsular thickening in professional baseball players who present with reduced throwing velocity related to pain and clinical findings of internal rotational deficit of the glenohumeral joint. Our observations of MR imaging features in patients with clinical and arthroscopic manifestations of GIRD lesions include articular surface partial thickness tears of the supraspinatus and infraspinatus tendons, superoposterior subluxation of the humeral head and SLAP tears of the labrum. Although no empiric standard currently exists for the axial dimension thickness of the shoulder capsule, we have observed a thickened appearance of the posterior band of the inferior glenohumeral ligament in these patients.

  20. Safety and effectiveness of minimally invasive sacroiliac joint fusion in women with persistent post-partum posterior pelvic girdle pain: 12-month outcomes from a prospective, multi-center trial.

    PubMed

    Capobianco, Robyn; Cher, Daniel

    2015-01-01

    Postpartum posterior pelvic girdle pain (PPGP) affects nearly 20 % of women who experience back pain in the peripartum period. The sacroiliac joint is a source of this pain in 75 % of women with persistent PPGP. A subset of women will fail to obtain acceptable pain relief from the current array of non-surgical treatment options. The purpose of this study is to assess the safety and effectiveness of minimally invasive sacroiliac (SI) joint fusion in women with chronic SI joint dysfunction whose pain began in the peri-partum period whose symptoms were recalcitrant to non-surgical management. A sub-group analysis of subjects with sacroiliac joint disruption and/or degenerative sacroiliitis enrolled in a prospective, multi-center trial of SI joint fusion was performed. Subjects with PPGP were identified and compared with women without PPGP and with men. Of 172 enrolled subjects, 52 were male, 100 were females without PPGP and 20 females had PPGP. PPGP subjects were significantly younger (43.3 years, vs. 52.8 for females without PPGP and 50.5 for men, p = 0.002). There were no differences in any other demographic or baseline clinical measure. Women with PPGP experienced a significant improvement in pain (-51 mm on VAS), function (-20.6 pts on ODI) and quality of life (SF-36 PCS +10.4, MCS +7.2, EQ-5D +0.31) at 12 months after surgery. These improvements were characteristic of the overall study results; no difference was detected between sub-groups. The sacroiliac joint can be a source of pain in women with persistent PPGP and should be investigated as a pain generator. In this study, women with carefully diagnosed chronic SI joint pain from PPGP recalcitrant to conservative therapies experienced clinically beneficially improvements in pain, disability and quality of life after minimally invasive SI joint fusion using a series of triangular porous plasma spray coated implants.

  1. Posterior tibial slope and femoral sizing affect posterior cruciate ligament tension in posterior cruciate-retaining total knee arthroplasty.

    PubMed

    Kuriyama, Shinichi; Ishikawa, Masahiro; Nakamura, Shinichiro; Furu, Moritoshi; Ito, Hiromu; Matsuda, Shuichi

    2015-08-01

    During cruciate-retaining total knee arthroplasty, surgeons sometimes encounter increased tension of the posterior cruciate ligament. This study investigated the effects of femoral size, posterior tibial slope, and rotational alignment of the femoral and tibial components on forces at the posterior cruciate ligament in cruciate-retaining total knee arthroplasty using a musculoskeletal computer simulation. Forces at the posterior cruciate ligament were assessed with the standard femoral component, as well as with 2-mm upsizing and 2-mm downsizing in the anterior-posterior dimension. These forces were also determined with posterior tibial slope angles of 5°, 7°, and 9°, and lastly, were measured in 5° increments when the femoral (tibial) components were positioned from 5° (15°) of internal rotation to 5° (15°) of external rotation. Forces at the posterior cruciate ligament increased by up to 718N with the standard procedure during squatting. The 2-mm downsizing of the femoral component decreased the force at the posterior cruciate ligament by up to 47%. The 2° increment in posterior tibial slope decreased the force at the posterior cruciate ligament by up to 41%. In addition, posterior cruciate ligament tension increased by 11% during internal rotation of the femoral component, and increased by 18% during external rotation of the tibial component. These findings suggest that accurate sizing and bone preparation are very important to maintain posterior cruciate ligament forces in cruciate-retaining total knee arthroplasty. Care should also be taken regarding malrotation of the femoral and tibial components because this increases posterior cruciate ligament tension. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Arthroscopic Preparation 0f the Posterior and Posteroinferior Glenoid Labrum

    DTIC Science & Technology

    2007-11-01

    cient traction to easily visual - ize and work in this area of the joint (Figure I). Glenohumeml arthroscopy is initiated from a standard posterior...flexion, and 10 Ibs of traction. the diagnostic glenohumeral arthroscopy is completed, a mid-glenoid (anteroinferior) portal is made just...lorrhaphy. Arthroscopy . 2006; 22:1138 el-5. Section Editor: Steven F. Harwin, MD NOVEMBER 2007 I Volume 30 • Number 11 3. Difelice GS , Williams RJ lil

  3. Multilevel cervical laminectomy and fusion with posterior cervical cages

    PubMed Central

    Bou Monsef, Jad N; Siemionow, Krzysztof B

    2017-01-01

    Context: Cervical spondylotic myelopathy (CSM) is a progressive disease that can result in significant disability. Single-level stenosis can be effectively decompressed through either anterior or posterior techniques. However, multilevel pathology can be challenging, especially in the presence of significant spinal stenosis. Three-level anterior decompression and fusion are associated with higher nonunion rates and prolonged dysphagia. Posterior multilevel laminectomies with foraminotomies jeopardize the bone stock required for stable fixation with lateral mass screws (LMSs). Aims: This is the first case series of multilevel laminectomy and fusion for CSM instrumented with posterior cervical cages. Settings and Design: Three patients presented with a history of worsening neck pain, numbness in bilateral upper extremities and gait disturbance, and examination findings consistent with myeloradiculopathy. Cervical magnetic resonance imaging demonstrated multilevel spondylosis resulting in moderate to severe bilateral foraminal stenosis at three cervical levels. Materials and Methods: The patients underwent a multilevel posterior cervical laminectomy and instrumented fusion with intervertebral cages placed between bilateral facet joints over three levels. Oswestry disability index and visual analog scores were collected preoperatively and at each follow-up. Pre- and post-operative images were analyzed for changes in cervical alignment and presence of arthrodesis. Results: Postoperatively, all patients showed marked improvement in neurological symptoms and neck pain. They had full resolution of radicular symptoms by 6 weeks postoperatively. At 12-month follow-up, they demonstrated solid arthrodesis on X-rays and computed tomography scan. Conclusions: Posterior cervical cages may be an alternative option to LMSs in multilevel cervical laminectomy and fusion for cervical spondylotic myeloradiculopathy. PMID:29403242

  4. Reversible posterior leucoencephalopathy syndrome associated with bone marrow transplantation.

    PubMed

    Teive, H A; Brandi, I V; Camargo, C H; Bittencourt, M A; Bonfim, C M; Friedrich, M L; de Medeiros, C R; Werneck, L C; Pasquini, R

    2001-09-01

    Reversible posterior leucoencephalopathy syndrome (RPLS) has previously been described in patients who have renal insufficiency, eclampsia, hypertensive encephalopathy and patients receiving immunosuppressive therapy. The mechanism by which immunosuppressive agents can cause this syndrome is not clear, but it is probably related with cytotoxic effects of these agents on the vascular endothelium. We report eight patients who received cyclosporine A (CSA) after allogeneic bone marrow transplantation or as treatment for severe aplastic anemia (SSA) who developed posterior leucoencephalopathy. The most common signs and symptoms were seizures and headache. Neurological dysfunction occurred preceded by or concomitant with high blood pressure and some degree of acute renal failure in six patients. Computerized tomography studies showed low-density white matter lesions involving the posterior areas of cerebral hemispheres. Symptoms and neuroimaging abnormalities were reversible and improvement occurred in all patients when given lower doses of CSA or when the drug was withdrawn. RPLS may be considered an expression of CSA neurotoxicity.

  5. Copula Models for Sociology: Measures of Dependence and Probabilities for Joint Distributions

    ERIC Educational Resources Information Center

    Vuolo, Mike

    2017-01-01

    Often in sociology, researchers are confronted with nonnormal variables whose joint distribution they wish to explore. Yet, assumptions of common measures of dependence can fail or estimating such dependence is computationally intensive. This article presents the copula method for modeling the joint distribution of two random variables, including…

  6. Significant effect of the posterior tibial slope and medial/lateral ligament balance on knee flexion in total knee arthroplasty.

    PubMed

    Fujimoto, Eisaku; Sasashige, Yoshiaki; Masuda, Yasuji; Hisatome, Takashi; Eguchi, Akio; Masuda, Tetsuo; Sawa, Mikiya; Nagata, Yoshinori

    2013-12-01

    The intra-operative femorotibial joint gap and ligament balance, the predictors affecting these gaps and their balances, as well as the postoperative knee flexion, were examined. These factors were assessed radiographically after a posterior cruciate-retaining total knee arthroplasty (TKA). The posterior condylar offset and posterior tibial slope have been reported as the most important intra-operative factors affecting cruciate-retaining-type TKAs. The joint gap and balance have not been investigated in assessments of the posterior condylar offset and the posterior tibial slope. The femorotibial gap and medial/lateral ligament balance were measured with an offset-type tensor. The femorotibial gaps were measured at 0°, 45°, 90° and 135° of knee flexion, and various gap changes were calculated at 0°-90° and 0°-135°. Cruciate-retaining-type arthroplasties were performed in 98 knees with varus osteoarthritis. The 0°-90° femorotibial gap change was strongly affected by the posterior condylar offset value (postoperative posterior condylar offset subtracted by the preoperative posterior condylar offset). The 0°-135° femorotibial gap change was significantly correlated with the posterior tibial slope and the 135° medial/lateral ligament balance. The postoperative flexion angle was positively correlated with the preoperative flexion angle, γ angle and the posterior tibial slope. Multiple-regression analysis demonstrated that the preoperative flexion angle, γ angle, posterior tibial slope and 90° medial/lateral ligament balance were significant independent factors for the postoperative knee flexion angle. The flexion angle change (postoperative flexion angle subtracted by the preoperative flexion angle) was also strongly correlated with the preoperative flexion angle, posterior tibial slope and 90° medial/lateral ligament balance. The postoperative flexion angle is affected by multiple factors, especially in cruciate-retaining-type TKAs. However, it is

  7. Innervation of the Anterior Sacroiliac Joint.

    PubMed

    Cox, Marcus; Ng, Garrett; Mashriqi, Faizullah; Iwanaga, Joe; Alonso, Fernando; Tubbs, Kevin; Loukas, Marios; Oskouian, Rod J; Tubbs, R Shane

    2017-11-01

    Sacroiliac joint pain can be disabling and recalcitrant to medical therapy. The innervation of this joint is poorly understood, especially its anterior aspect. Therefore, the present cadaveric study was performed to better elucidate this anatomy. Twenty-four cadaveric sides underwent dissection of the anterior sacroiliac joint, with special attention given to any branches from regional nerves to this joint. No femoral, obturator, or lumbosacral trunk branches destined to the anterior sacroiliac joint were identified in the 24 sides. In 20 sides, one or two small branches (less than 0.5 mm in diameter) were found to arise from the L4 ventral ramus (10%), the L5 ventral ramus (80%), or simultaneously from both the L4 and L5 ventral rami (10%). The length of the branches ranged from 5 to 31 mm (mean, 14 mm). All these branches arose from the posterior part of the nerves and traveled to the anterior surface of the sacroiliac joint. No statistical significance was found between sides or sexes. An improved knowledge of the innervation of the anterior sacroiliac joint might decrease suffering in patients with chronic sacroiliac joint pain. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Posterior semicircular canal dehiscence: value of VEMP and multidetector CT.

    PubMed

    Vanspauwen, R; Salembier, L; Van den Hauwe, L; Parizel, P; Wuyts, F L; Van de Heyning, P H

    2006-01-01

    To illustrate that posterior semicircular canal dehiscence can present similarly to superior semicircular canal dehiscence. The symptomatology initially presented as probable Menière's disease evolving into a mixed conductive hearing loss with a Carhart notch-type perceptive component suggestive of otosclerosis-type stapes fixation. A small hole stapedotomy resulted in a dead ear and a horizontal semicircular canal hypofunction. Recurrent incapacitating vertigo attacks developed. Vestibular evoked myogenic potential (VEMP) testing demonstrated intact vestibulocollic reflexes. Additional evaluation with high resolution multidetector computed tomography (MDCT) of the temporal bone showed a dehiscence of the left posterior semicircular canal. Besides superior semicircular canal dehiscence, posterior semicircular canal dehiscence has to be included in the differential diagnosis of atypical Menière's disease and/or low tone conductive hearing loss. The value of performing MDCT before otosclerosis-type surgery is stressed. VEMP might contribute to establishing the differential diagnosis.

  9. Long-term evaluation of posterior lateral meniscus root tears left in situ at the time of anterior cruciate ligament reconstruction.

    PubMed

    Shelbourne, K Donald; Roberson, Troy A; Gray, Tinker

    2011-07-01

    The long-term radiographic and subjective results of patients with posterior lateral meniscus root tears left in situ at the time of anterior cruciate ligament reconstruction has not been reported. The authors hypothesized that patients who had posterior lateral meniscus root tears left in situ would have statistically significantly lower subjective scores and greater joint-space narrowing as compared with a control group. Cohort study; Level of evidence, 3. Thirty-three patients who had isolated posterior lateral meniscus root tear and >5 years objective and subjective follow-up were evaluated and compared with a matched control group without meniscal tears based on sex, chronicity of tear, age, and follow-up time. Patients were evaluated subjectively and objectively using the International Knee Documentation Committee criteria. The mean objective follow-up time was 10.6 ± 4.5 years. The mean subjective total score was 84.6 ± 14 in the study group versus 90.5 ± 13 in the control group (P = .09). Radiographs showed lateral joint-space narrowing rated as normal in 19, mild in 10, moderate in 3, and severe in 1 versus the control group, which was normal in 28 and mild in 5 patients. The measured amount of lateral joint-space narrowing compared with the other knee was 1.0 ± 1.6 mm in the study group versus 0 ± 1.1 mm in the controls on 45° flexed posteroanterior radiographs (P < .006). At a mean of 10 years' follow-up of posterior lateral meniscus root tears left in situ, mild lateral joint-space narrowing was measured without significant differences in subjective or objective scores compared with controls. This study provides a baseline that can be used to compare the results of procedures used to treat these tears in other manners.

  10. The influence of simulated transversus abdominis muscle force on sacroiliac joint flexibility during asymmetric moment application to the pelvis.

    PubMed

    Gnat, Rafael; Spoor, Kees; Pool-Goudzwaard, Annelies

    2015-10-01

    The role of so-called local muscle system in motor control of the lower back and pelvis is a subject of ongoing debate. Prevailing beliefs in stabilizing function of this system were recently challenged. This study investigated the impact of in vitro simulated force of transversely oriented fibres of the transversus abdominis muscle (a part of the local system) on flexibility of the sacroiliac joint during asymmetric moment application to the pelvis. In 8 embalmed specimens an incremental moment was applied in the sagittal plane to one innominate with respect to the fixed contralateral innominate. Ranges of motion of the sacroiliac joint were recorded using the Vicon Motion Capture System. Load-deformation curves were plotted and flexibility of the sacroiliac joint was calculated separately for anterior and posterior rotations of the innominate, with and without simulated muscle force. Flexibility of the sacroiliac joint was significantly bigger during anterior rotation of the innominate, as compared to posterior rotation (Anova P<0.05). After application of simulated force of transversus abdominis, flexibility of the joint did not change both during anterior and posterior rotations of the innominate. A lack of a stiffening effect of simulated transversus abdominis force on the sacroiliac joint was demonstrated. Earlier hypotheses suggesting a stiffening influence of this muscle on the pelvis cannot be confirmed. Consistent with previous findings smaller flexibility of the joint recorded during posterior rotation of the innominate may be of clinical importance for physio- and manual therapists. However, major limitations of the study should be acknowledged: in vitro conditions and simulation of only solitary muscle force. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Medial meniscal posterior root/horn radial tears correlate with cartilage degeneration detected by T1ρ relaxation mapping.

    PubMed

    Takahashi, Kenji; Hashimoto, Sanshiro; Nakamura, Hiroshi; Mori, Atsushi; Sato, Akiko; Majima, Tokifumi; Takai, Shinro

    2015-06-01

    This study aimed to identify factors on routine pulse sequence MRI associated with cartilage degeneration observed on T1ρ relaxation mapping. This study included 137 subjects with knee pain. T1ρ values were measured in the regions of interest on the surface layer of the cartilage on mid-coronal images of the femorotibial joint. Assessment of cartilage, subchondral bone, meniscus and ligaments was performed using routine pulse sequence MRI. Radiographic evaluation for osteoarthritis was also performed. Multiple regression analysis revealed posterior root/horn tears to be independent factors increasing the T1ρ values of the cartilage in the medial compartment of the femorotibial joint. Even when adjusted for radiographically defined early-stage osteoarthritis, medial posterior meniscal radial tears significantly increased the T1ρ values. This study showed that posterior root/horn radial tears in the medial meniscus are particularly important MRI findings associated with cartilage degeneration observed on T1ρ relaxation mapping. Morphological factors of the medial meniscus on MRI provide findings useful for screening early-stage osteoarthritis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Medial Meniscus Posterior Root Tear Repair Using a 2-Simple-Suture Pullout Technique.

    PubMed

    Samy, Tarek Mohamed; Nassar, Wael A M; Zakaria, Zeiad Mohamed; Farrag Abdelaziz, Ahmed Khaled

    2017-06-01

    Medial meniscus posterior root tear is one of the underestimated knee injuries in terms of incidence. Despite its grave sequelae, using simple but effective technique can maintain the native knee joint longevity. In the current note, a 2-simple-suture pullout technique was used to effectively reduce the meniscus posterior root to its anatomic position. The success of the technique depended on proper tool selection as well as tibial tunnel direction that allowed easier root suturing and better suture tensioning, without inducing any iatrogenic articular cartilage injury or meniscal tissue loss. Using anterior knee arthroscopy portals, anterolateral as a viewing portal and anteromedial as a working portal, a 7-mm tibial tunnel starting at Gerdy tubercle and ending at the medial meniscus posterior root bed was created. The 2 simple sutures were retrieved through the tunnel and tensioned and secured over a 12-mm-diameter washer at the tibial tunnel outer orifice. Anatomic reduction of the medial meniscus posterior root tear was confirmed arthroscopically intraoperatively and radiologically by postoperative magnetic resonance imaging.

  13. Interrater reliability of identifying indicators of posterior ligamentous complex disruption when plain films are indeterminate in thoracolumbar injuries.

    PubMed

    Schweitzer, Karl M; Vaccaro, Alexander R; Harrop, James S; Hurlbert, John; Carrino, John A; Rechtine, Glenn R; Schwartz, David G; Alanay, Ahmet; Sharma, Dinesh K; Anderson, D Greg; Lee, Joon Y; Arnold, Paul M

    2007-09-01

    The Spine Trauma Study Group (STSG) has proposed a novel thoracolumbar injury classification system and score (TLICS) in an attempt to define traumatic spinal injuries and direct appropriate management schemes objectively. The TLICS assigns specific point values based on three variables to generate a final severity score that guides potential treatment options. Within this algorithm, significant emphasis has been placed on posterior ligamentous complex (PLC) integrity. The purpose of this study was to determine the interrater reliability of indicators surgeons use when assessing PLC disruption on imaging studies, including computed tomography (CT) and magnetic resonance imaging (MRI). Orthopedic surgeons and neurosurgeons retrospectively reviewed a series of thoracolumbar injury case studies. Thirteen case studies, including images, were distributed to STSG members for individual, independent evaluation of the following three criteria: (1) diastasis of the facet joints on CT; (2) posterior edema-like signal in the region of PLC components on sagittal T2-weighted fat saturation (FAT SAT) MRI; and (3) disrupted PLC components on sagittal T1-weighted MRI. Interrater agreement on the presence or absence of each of the three criteria in each of the 13 cases was assessed. Absolute interrater percent agreement on diastasis of the facet joints on CT and posterior edema-like signal in the region of PLC components on sagittal T2-weighted FAT SAT MRI was similar (agreement 70.5%). Interrater agreement on disrupted PLC components on sagittal T1-weighted MRI was 48.9%. Facet joint diastasis on CT was the most reliable indicator of PLC disruption as assessed by both Cohen's kappa (kappa = 0.395) and intraclass correlation coefficient (ICC 0.430). The interrater reliability of assessing diastasis of the facet joints on CT had fair to moderate agreement. The reliability of assessing the posterior edema-like signal in the region of PLC components was lower but also fair, whereas

  14. A Study of Knee Joint Kinematics and Mechanics using a Human FE Model.

    PubMed

    Kitagawa, Yuichi; Hasegawa, Junji; Yasuki, Tsuyoshi; Iwamoto, Masami; Miki, Kazuo

    2005-11-01

    Posterior translation of the tibia with respect to the femur can stretch the posterior cruciate ligament (PCL). Fifteen millimeters of relative displacement between the femur and tibia is known as the Injury Assessment Reference Value (IARV) for the PCL injury. Since the anterior protuberance of the tibial plateau can be the first site of contact when the knee is flexed, the knee bolster is generally designed with an inclined surface so as not to directly load the projection in frontal crashes. It should be noted, however, that the initial flexion angle of the occupant knee can vary among individuals and the knee flexion angle can change due to the occupant motion. The behavior of the tibial protuberance related to the knee flexion angle has not been described yet. The instantaneous angle of the knee joint at the timing of restraining the knee should be known to manage the geometry and functions of knee restraint devices. The purposes of this study are first to understand the kinematics of the knee joint during flexion, and second to characterize the mechanics of the knee joint under anterior-posterior loading. A finite element model of the knee joint, extracted from the Total Human Model for Safety (THUMS), was used to analyze the mechanism. The model was validated against kinematics and mechanical responses of the human knee joint. By tracking the relative positions and angles between the patella and the tibia in a knee flexing simulation, the magnitude of the tibial anterior protuberance was described as a function of the knee joint angle. The model revealed that the mechanics of the knee joint was characterized as a combination of stiffness of the patella-femur structure and the PCL It was also found that the magnitude of the tibial anterior protuberance determined the amount of initial stretch of the PCL in anterior-posterior loading. Based on the knee joint kinematics and mechanics, an interference boundary was proposed for different knee flexion angles, so

  15. Arthroscopic repair of the posterior horn of the medial meniscus with opening wedge high tibial osteotomy: surgical technique.

    PubMed

    Jung, Kwang Am; Kim, Sung Jae; Lee, Su Chan; Jeong, Jae Hoon; Song, Moon Bok; Lee, Choon Key

    2009-07-01

    Simultaneous repair of a radial tear at the tibial attachment site of the posterior horn of the medial meniscus under special circumstances requiring tibial valgus osteotomy is technically difficult. First, most patients who need an osteotomy have a narrowed medial tibiofemoral joint space. In such a situation, the pull-out suture technique is more difficult to perform than in a normal joint space. Second, pulling out suture strands that penetrate the posterior horn of the medial meniscus to the anterior tibial cortex increases the risk of transection during osteotomy. We performed a meniscus repair combined with an opening wedge tibial valgus osteotomy without complications and present our technique as a new method for use in selective cases necessitating both meniscus repair of a complete radial tear and opening wedge tibial osteotomy.

  16. Judging the Probability of Hypotheses Versus the Impact of Evidence: Which Form of Inductive Inference Is More Accurate and Time-Consistent?

    PubMed

    Tentori, Katya; Chater, Nick; Crupi, Vincenzo

    2016-04-01

    Inductive reasoning requires exploiting links between evidence and hypotheses. This can be done focusing either on the posterior probability of the hypothesis when updated on the new evidence or on the impact of the new evidence on the credibility of the hypothesis. But are these two cognitive representations equally reliable? This study investigates this question by comparing probability and impact judgments on the same experimental materials. The results indicate that impact judgments are more consistent in time and more accurate than probability judgments. Impact judgments also predict the direction of errors in probability judgments. These findings suggest that human inductive reasoning relies more on estimating evidential impact than on posterior probability. Copyright © 2015 Cognitive Science Society, Inc.

  17. Posterior Shoulder Instability

    PubMed Central

    Antosh, Ivan J.; Tokish, John M.; Owens, Brett D.

    2016-01-01

    Context: Posterior shoulder instability has become more frequently recognized and treated as a unique subset of shoulder instability, especially in the military. Posterior shoulder pathology may be more difficult to accurately diagnose than its anterior counterpart, and commonly, patients present with complaints of pain rather than instability. “Posterior instability” may encompass both dislocation and subluxation, and the most common presentation is recurrent posterior subluxation. Arthroscopic and open treatment techniques have improved as understanding of posterior shoulder instability has evolved. Evidence Acquisition: Electronic databases including PubMed and MEDLINE were queried for articles relating to posterior shoulder instability. Study Design: Clinical review. Level of Evidence: Level 4. Results: In low-demand patients, nonoperative treatment of posterior shoulder instability should be considered a first line of treatment and is typically successful. Conservative treatment, however, is commonly unsuccessful in active patients, such as military members. Those patients with persistent shoulder pain, instability, or functional limitations after a trial of conservative treatment may be considered surgical candidates. Arthroscopic posterior shoulder stabilization has demonstrated excellent clinical outcomes, high patient satisfaction, and low complication rates. Advanced techniques may be required in select cases to address bone loss, glenoid dysplasia, or revision. Conclusion: Posterior instability represents about 10% of shoulder instability and has become increasingly recognized and treated in military members. Nonoperative treatment is commonly unsuccessful in active patients, and surgical stabilization can be considered in patients who do not respond. Isolated posterior labral repairs constitute up to 24% of operatively treated labral repairs in a military population. Arthroscopic posterior stabilization is typically considered as first-line surgical

  18. Arthroscopic Direct Repair for a Complete Radial Tear of the Posterior Root of the Medial Meniscus

    PubMed Central

    Wang, Kook Hyun; Hwang, Dae Hee; Cho, Jin Ho; Changale, Sachin D.; Woo, Sung Jong

    2011-01-01

    We report here on a new arthroscopic direct repair technique for a radial tear of the posterior root of the medial meniscus (PRMM) using a posterior trans-septal portal. Radial tears of the PRMM are commonly observed in the elderly population of Korea and Japan, and the life style of these people requires squatting and kneeling down in daily life. A radial tear of the PRMM results in the loss of hoop tension and this accelerates degenerative changes in the knee joint and causes early osteoarthritis. Several reports in the medical literature have focused on various repair techniques for these tears by using pull out sutures. These techniques result in nonanatomic fixation of the meniscus, which may lead to disturbed meniscal excursion and failure to restore hoop tension. Arthroscopic direct repair may contribute to restoring hoop tension and preventing accelerated degenerative changes in the knee joint of these patients. PMID:22162797

  19. Arthroscopic direct repair for a complete radial tear of the posterior root of the medial meniscus.

    PubMed

    Wang, Kook Hyun; Hwang, Dae Hee; Cho, Jin Ho; Changale, Sachin D; Woo, Sung Jong; Nha, Kyung Wook

    2011-12-01

    We report here on a new arthroscopic direct repair technique for a radial tear of the posterior root of the medial meniscus (PRMM) using a posterior trans-septal portal. Radial tears of the PRMM are commonly observed in the elderly population of Korea and Japan, and the life style of these people requires squatting and kneeling down in daily life. A radial tear of the PRMM results in the loss of hoop tension and this accelerates degenerative changes in the knee joint and causes early osteoarthritis. Several reports in the medical literature have focused on various repair techniques for these tears by using pull out sutures. These techniques result in nonanatomic fixation of the meniscus, which may lead to disturbed meniscal excursion and failure to restore hoop tension. Arthroscopic direct repair may contribute to restoring hoop tension and preventing accelerated degenerative changes in the knee joint of these patients.

  20. Evaluation of joint probability density function models for turbulent nonpremixed combustion with complex chemistry

    NASA Technical Reports Server (NTRS)

    Smith, N. S. A.; Frolov, S. M.; Bowman, C. T.

    1996-01-01

    Two types of mixing sub-models are evaluated in connection with a joint-scalar probability density function method for turbulent nonpremixed combustion. Model calculations are made and compared to simulation results for homogeneously distributed methane-air reaction zones mixing and reacting in decaying turbulence within a two-dimensional enclosed domain. The comparison is arranged to ensure that both the simulation and model calculations a) make use of exactly the same chemical mechanism, b) do not involve non-unity Lewis number transport of species, and c) are free from radiation loss. The modified Curl mixing sub-model was found to provide superior predictive accuracy over the simple relaxation-to-mean submodel in the case studied. Accuracy to within 10-20% was found for global means of major species and temperature; however, nitric oxide prediction accuracy was lower and highly dependent on the choice of mixing sub-model. Both mixing submodels were found to produce non-physical mixing behavior for mixture fractions removed from the immediate reaction zone. A suggestion for a further modified Curl mixing sub-model is made in connection with earlier work done in the field.

  1. Quantification of dynamic posterior translation in modified bilateral Alexander views and correlation with clinical and radiological parameters in patients with acute acromioclavicular joint instability.

    PubMed

    Minkus, Marvin; Hann, Carmen; Scheibel, Markus; Kraus, Natascha

    2017-06-01

    Classification of AC-joint instability is based on radiologic evaluation of anteroposterior (a.p.) stress views of both shoulders, neglecting the horizontal component of instability. Recent studies have proposed an association of dynamic posterior translation (DPT) and inferior clinical results. The purpose of this study was to quantify DPT in modified Alexander views and correlate it with other radiological and clinical data. Thirty-two patients (4 f, 28 m, mean age 34.1) with acute AC-joint dislocation (16 = RW III, 16 = RW V) underwent radiological examination including bilateral a.p. stress views with measurement of the coracoclavicular distance (CCD) and bilateral modified Alexander views with different approaches to quantify DPT (overlapping area OA AC , overlapping length OL AC ). In addition, the Constant Score, Subjective Shoulder Value, Taft Score (TF), and the Acromioclavicular Joint Instability Score (ACJI) were obtained. In Rockwood (RW) type III injuries, a mean CCD of 15.8 (9.8-22.8) mm, OA AC of 50.9 (0-216.6) mm 2 , and OL AC of 6.5 (-4.7-17.9) mm were found. RW V patients showed a CCD of 23.1 (13.7-32.0) mm; OA AC 7.0 (0-92.3) mm 2 ; and OL AC -4.8 (-19.6-9.8) mm. Particularly in RW III the CCD, OA AC and OL AC revealed significant correlation with the ACJI (r = -0.64/r = 0.72/r = 0.68, p < 0.05) and TF (r = -0.56/r = 0.68/r = 0.51, p < 0.05). The proposed quantification tools for DPT were found to have a moderate-to-strong correlation with the score results, especially with AC-joint specific scores. RW type V injuries had a moderate correlation with clinical parameters (OA AC with ACJI: r = 0.44, p > 0.05 and OL AC with TF: r = -0.45, p > 0.05). Measuring the OL AC is a convenient way for quantifying DPT in modified Alexander views. It showed significant correlation with clinical scores, indicating the relevance of DPT in patients with AC-joint injury.

  2. Bivariate normal, conditional and rectangular probabilities: A computer program with applications

    NASA Technical Reports Server (NTRS)

    Swaroop, R.; Brownlow, J. D.; Ashwworth, G. R.; Winter, W. R.

    1980-01-01

    Some results for the bivariate normal distribution analysis are presented. Computer programs for conditional normal probabilities, marginal probabilities, as well as joint probabilities for rectangular regions are given: routines for computing fractile points and distribution functions are also presented. Some examples from a closed circuit television experiment are included.

  3. Quantification of functional brace forces for posterior cruciate ligament injuries on the knee joint: an in vivo investigation.

    PubMed

    LaPrade, Robert F; Smith, Sean D; Wilson, Katharine J; Wijdicks, Coen A

    2015-10-01

    Counteracting posterior translation of the tibia with an anterior force on the posterior proximal tibia has been demonstrated clinically to improve posterior knee laxity following posterior cruciate ligament (PCL) injury. This study quantified forces applied to the posterior proximal tibia by two knee braces designed for treatment of PCL injuries. The forces applied by two knee braces to the posterior proximal tibia and in vivo three-dimensional knee kinematics of six adult, male, healthy volunteer subjects (mean ± standard deviation: height, 182.5 ± 5.2 cm; body mass, 83.2 ± 9.3 kg; body mass index, 24.9 ± 1.5 kg/m(2); age, 25.8 ± 2.9 years) were measured using a custom pressure mapping technique and traditional surface marker motion capture techniques, while subjects performed three functional activities. The activities included seated unloaded knee flexion, squatting, and stair descent in a new generation dynamic force (DF) PCL brace and a static force (SF) PCL brace. During unloaded flexion at the lowest force level setting, the force applied by the DF brace increased as a function of flexion angle (slope = 0.7 N/°; p < 0.001) compared to the SF brace effect. Force applied by the SF brace did not significantly change as a function of flexion angle (slope = 0.0 N/°; n.s.). By 45° of flexion, the average force applied by the DF brace (48.1 N) was significantly larger (p < 0.001) than the average force applied by the SF brace (25.0 N). The difference in force continued to increase as flexion angle increased. During stair descent, average force (mean ± standard deviation) at toe off was significantly higher (p = 0.013) for the DF brace (78.7 ± 21.6 N) than the SF brace (37.3 ± 7.2 N). Similar trends were observed for squatting and for the higher force level settings. The DF brace applied forces to the posterior proximal tibia that dynamically increased with increased flexion angle. Additionally, the DF brace applied

  4. The Effect on Long-Term Survivorship of Surgeon Preference for Posterior-Stabilized or Minimally Stabilized Total Knee Replacement: An Analysis of 63,416 Prostheses from the Australian Orthopaedic Association National Joint Replacement Registry.

    PubMed

    Vertullo, Christopher J; Lewis, Peter L; Lorimer, Michelle; Graves, Stephen E

    2017-07-05

    Controversy still exists as to the optimum management of the posterior cruciate ligament (PCL) in total knee arthroplasty. Surgeons can choose to kinematically substitute the PCL with a posterior-stabilized total knee replacement or alternatively to utilize a cruciate-retaining, also known as minimally stabilized, total knee replacement. Proponents of posterior-stabilized total knee replacement propose that the reported lower survivorship in registries when directly compared with minimally stabilized total knee replacement is due to confounders such as selection bias because of the preferential usage of posterior-stabilized total knee replacement in more complex or severe cases. In this study, we aimed to eliminate these possible confounders by performing an instrumental variable analysis based on surgeon preference to choose either posterior-stabilized or minimally stabilized total knee replacement, rather than the actual prosthesis received. Cumulative percent revision, hazard ratio (HR), and revision diagnosis data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry from September 1, 1999, to December 31, 2014, for 2 cohorts of patients, those treated by high-volume surgeons who preferred minimally stabilized replacements and those treated by high-volume surgeons who preferred posterior-stabilized replacements. All patients had a diagnosis of osteoarthritis and underwent fixed-bearing total knee replacement with patellar resurfacing. At 13 years, the cumulative percent revision was 5.0% (95% confidence interval [CI], 4.0% to 6.2%) for the surgeons who preferred the minimally stabilized replacements compared with 6.0% (95% CI, 4.2% to 8.5%) for the surgeons who preferred the posterior-stabilized replacements. The revision risk for the surgeons who preferred posterior-stabilized replacements was significantly higher for all causes (HR = 1.45 [95% CI, 1.30 to 1.63]; p < 0.001), for loosening or lysis (HR = 1.93 [95% CI, 1

  5. Preservation of kinematics with posterior cruciate-, bicruciate- and patient-specific bicruciate-retaining prostheses in total knee arthroplasty by using computational simulation with normal knee model

    PubMed Central

    Koh, Y-G.; Son, J.; Kwon, S-K.; Kim, H-J.; Kang, K-T.

    2017-01-01

    Objectives Preservation of both anterior and posterior cruciate ligaments in total knee arthroplasty (TKA) can lead to near-normal post-operative joint mechanics and improved knee function. We hypothesised that a patient-specific bicruciate-retaining prosthesis preserves near-normal kinematics better than standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining prostheses in TKA. Methods We developed the validated models to evaluate the post-operative kinematics in patient-specific bicruciate-retaining, standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under gait and deep knee bend loading conditions using numerical simulation. Results Tibial posterior translation and internal rotation in patient-specific bicruciate-retaining prostheses preserved near-normal kinematics better than other standard off-the-shelf prostheses under gait loading conditions. Differences from normal kinematics were minimised for femoral rollback and internal-external rotation in patient-specific bicruciate-retaining, followed by standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under deep knee bend loading conditions. Moreover, the standard off-the-shelf posterior cruciate-retaining TKA in this study showed the most abnormal performance in kinematics under gait and deep knee bend loading conditions, whereas patient-specific bicruciate-retaining TKA led to near-normal kinematics. Conclusion This study showed that restoration of the normal geometry of the knee joint in patient-specific bicruciate-retaining TKA and preservation of the anterior cruciate ligament can lead to improvement in kinematics compared with the standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining TKA. Cite this article: Y-G. Koh, J. Son, S-K. Kwon, H-J. Kim, O-R. Kwon, K-T. Kang. Preservation of kinematics with posterior cruciate-, bicruciate- and patient-specific bicruciate-retaining prostheses in total knee

  6. Influence of bi- and tri-compartmental knee arthroplasty on the kinematics of the knee joint.

    PubMed

    Wünschel, Markus; Lo, Jiahsuan; Dilger, Torsten; Wülker, Nikolaus; Müller, Otto

    2011-01-27

    The cruciate ligaments are important stabilizers of the knee joint and determine joint kinematics in the natural knee and after cruciate retaining arthroplasty.No in vitro data is available to biomechanically evaluate the ability of the anterior cruciate ligament (ACL) to maintain knee joint kinematics after bicruciate-retaining bi-compartmental knee arthroplasty (BKA).Therefore, the objective of the current study was to investigate the kinematics of the natural knee joint, before and after installing bicruciate-retaining BKA and posterior cruciate retaining total knee arthroplasty. Specifically, we incorporated a dynamic knee simulator to simulate weight-bearing flexions on cadaveric knee specimen before and after surgical manipulations. In this cadaveric study we investigated rotational and translational tibiofemoral kinematics during simulated weight-bearing flexions of the intact knee, after bi-compartmental knee arthroplasty (BKA+), after resecting the ACL in BKA (BKA-), and after posterior cruciate retaining total knee arthroplasty (TKA). Rotation of BKA+ is closest to the intact knee joint, whereas TKA shows significant differences from 30 to 90 degree of flexion. Within the tested flexion range (15 to 90 degree of flexion), there was no significant difference in the anterior-posterior translation among intact, BKA+, and TKA knees. Resecting the ACL in BKA leads to a significant anterior tibial translation. BKA with intact cruciate ligaments resembles rotation and translation of the natural knee during a simulated weight-bearing flexion. It is a suitable treatment option for medial and patellofemoral osteoarthritis with advantages in rotational characteristics compared to TKA.

  7. [Minimally invasive approaches to hip and knee joints for total joint replacement].

    PubMed

    Rittmeister, M; König, D P; Eysel, P; Kerschbaumer, F

    2004-11-01

    The manuscript features the different minimally invasive approaches to the hip for joint replacement. These include medial, anterior, anterolateral, and posterior approaches. The concept of minimally invasive hip arthroplasty makes sense if it is an integral part of a larger concept to lower postoperative morbidity. Besides minimal soft tissue trauma, this concept involves preoperative patient education, preemptive analgesia, and postoperative physiotherapy. It is our belief that minimal incision techniques for the hip are not suited for all patients and all surgeons. The different minimally invasive approaches to the knee joint for implantation of a knee arthroplasty are described and discussed. There have been no studies published yet that fulfill EBM criteria. The data so far show that minimally invasive approaches and implantation techniques for total knee replacements lead to quicker rehabilitation of patients.

  8. Mechanisms of anterior-posterior stability of the knee joint under load-bearing.

    PubMed

    Reynolds, Ryan J; Walker, Peter S; Buza, John

    2017-05-24

    The anterior-posterior (AP) stability of the knee is an important aspect of functional performance. Studies have shown that the stability increases when compressive loads are applied, as indicated by reduced laxity, but the mechanism has not been fully explained. A test rig was designed which applied combinations of AP shear and compressive forces, and measured the AP displacements relative to the neutral position. Five knees were evaluated at compressive loads of 0, 250, 500, and 750N, with the knee at 15° flexion. At each load, three cycles of shear force at ±100N were applied. For the intact knee under load, the posterior tibial displacement was close to zero, due to the upward slope of the anterior medial tibial surface. The soft tissues were then resected in sequence to determine their role in AP laxity. After anterior cruciate ligament (ACL) resection, the anterior tibial displacement increased significantly even under load, highlighting its importance in stability. Meniscal resection further increased displacement but also the vertical displacement increased, implying the meniscus was providing a buffering effect. The PCL had no effect on any of the displacements under load. Plowing cartilage deformation and surface friction were negligible. This work highlighted the particular importance of the upward slope of the anterior medial tibial surface and the ACL to AP knee stability under load. The results are relevant to the design of total knees which reproduce anatomic knee stability behavior. Copyright © 2017. Published by Elsevier Ltd.

  9. The effect of in vivo rotator cuff muscle contraction on glenohumeral joint translation: An ultrasonographic and electromyographic study.

    PubMed

    Rathi, Sangeeta; Taylor, Nicholas F; Green, Rodney A

    2016-12-08

    The proposed stabilizing mechanism of rotator cuff muscles is to limit excessive humeral head translation. However, an accurate measurement of glenohumeral joint translation in vivo has been challenging. We aimed to measure the effect of rotator cuff muscle contraction on glenohumeral joint translation using real time ultrasound (RTUS) and electromyography. Twenty healthy adults with no history of shoulder pathology were recruited. Six intramuscular electrodes were inserted in the rotator cuff muscles (supraspinatus, upper and lower infraspinatus, teres minor, upper and lower subscapularis). Anterior and posterior glenohumeral translations were measured in testing conditions (with and without translation force, with and without isometric internal and external rotation), in two positions (shoulder neutral, abduction) and views (anterior, posterior). There was reduced glenohumeral translation with rotator cuff muscle contraction in the neutral anterior (F 2,38 =17.8, p<0.01), neutral posterior (F 1.6,31.0 =44.3, p<0.01) and abducted posterior (F 1.5,28.8 =5.2, p<0.02) positions. There were also differences between the amount of translation limited by anterior and posterior rotator cuff muscles in response to anterior and posterior translation forces (p<0.05), indicating that their activity was, to a certain extent, direction specific. For example, in both neutral and abducted positions, contraction of the posterior rotator cuff muscles, infraspinatus and teres minor, appeared to tether anterior translation of the humeral head. Our results confirm that the rotator cuff functions as a stabilizer of the glenohumeral joint by limiting humeral head translation and this is likely to be in a direction-specific manner. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Bayesian inference for the distribution of grams of marijuana in a joint.

    PubMed

    Ridgeway, Greg; Kilmer, Beau

    2016-08-01

    The average amount of marijuana in a joint is unknown, yet this figure is a critical quantity for creating credible measures of marijuana consumption. It is essential for projecting tax revenues post-legalization, estimating the size of illicit marijuana markets, and learning about how much marijuana users are consuming in order to understand health and behavioral consequences. Arrestee Drug Abuse Monitoring data collected between 2000 and 2010 contain relevant information on 10,628 marijuana transactions, joints and loose marijuana purchases, including the city in which the purchase occurred and the price paid for the marijuana. Using the Brown-Silverman drug pricing model to link marijuana price and weight, we are able to infer the distribution of grams of marijuana in a joint and provide a Bayesian posterior distribution for the mean weight of marijuana in a joint. We estimate that the mean weight of marijuana in a joint is 0.32g (95% Bayesian posterior interval: 0.30-0.35). Our estimate of the mean weight of marijuana in a joint is lower than figures commonly used to make estimates of marijuana consumption. These estimates can be incorporated into drug policy discussions to produce better understanding about illicit marijuana markets, the size of potential legalized marijuana markets, and health and behavior outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. Joint Bayesian Component Separation and CMB Power Spectrum Estimation

    NASA Technical Reports Server (NTRS)

    Eriksen, H. K.; Jewell, J. B.; Dickinson, C.; Banday, A. J.; Gorski, K. M.; Lawrence, C. R.

    2008-01-01

    We describe and implement an exact, flexible, and computationally efficient algorithm for joint component separation and CMB power spectrum estimation, building on a Gibbs sampling framework. Two essential new features are (1) conditional sampling of foreground spectral parameters and (2) joint sampling of all amplitude-type degrees of freedom (e.g., CMB, foreground pixel amplitudes, and global template amplitudes) given spectral parameters. Given a parametric model of the foreground signals, we estimate efficiently and accurately the exact joint foreground- CMB posterior distribution and, therefore, all marginal distributions such as the CMB power spectrum or foreground spectral index posteriors. The main limitation of the current implementation is the requirement of identical beam responses at all frequencies, which restricts the analysis to the lowest resolution of a given experiment. We outline a future generalization to multiresolution observations. To verify the method, we analyze simple models and compare the results to analytical predictions. We then analyze a realistic simulation with properties similar to the 3 yr WMAP data, downgraded to a common resolution of 3 deg FWHM. The results from the actual 3 yr WMAP temperature analysis are presented in a companion Letter.

  12. Arthroscopic pullout repair of posterior root tear of the medial meniscus: the anterior approach using medial collateral ligament pie-crusting release.

    PubMed

    Park, Young-Sik; Moon, Hong-Kyo; Koh, Yong-Gon; Kim, Yong-Chan; Sim, Dong-Sik; Jo, Seung-Bae; Kwon, Se-Kwang

    2011-08-01

    Posterior root tears of the medial meniscus are frequently encountered and should be repaired if possible to prevent osteoarthritis of the medial compartment. Various surgical techniques have been proposed to repair posterior root tears. The anterior arthroscopic approach can cause an iatrogenic chondral injury due to the narrow medial joint space. The posterior approaches might be technically unfamiliar to many surgeons because they require the establishment of a posteromedial or trans-septal portal. This paper describes the medial collateral ligament pie-crusting release technique for arthroscopic double transosseous pullout repair of posterior root tears of the medial meniscus through the anterior approach to provide the good visualization of the footprint and sufficient working space.

  13. Medial meniscus posterior root tear induces pathological posterior extrusion of the meniscus in the knee-flexed position: An open magnetic resonance imaging analysis.

    PubMed

    Masuda, S; Furumatsu, T; Okazaki, Y; Kodama, Y; Hino, T; Kamatsuki, Y; Miyazawa, S; Ozaki, T

    2018-04-10

    A medial meniscus posterior root tear (MMPRT) is defined as an injury to the posterior meniscal insertion on the tibia. In MMPRT, the medial meniscus (MM) hoop function is damaged, and the MM undergoes a medial extrusion into the interior from the superior articular surface of the tibia. However, the details of MM position and movement during knee joint movement are unclear in MMPRT cases. The present study aims to evaluate MM position and movement via magnetic resonance imaging (MRI) examination of the MM posterior extrusion (MMPE) at knee flexion angles of 10° and 90°. We hypothesized that, during knee flexion, the MM will shift to the posterior and the posterior extrusion will increase compared to that when the knee is extended. Twenty-four patients were diagnosed with symptomatic MMPRT on open MRI examination. Preoperative MMPE, anteroposterior interval (API) of the MM, and MM medial extrusion (MMME) at knee flexion angles of 10° and 90° were measured. For patients with MMPRT, the MMPE increased from -4.77±1.43mm to 3.79±1.17mm (p<0.001) when the knee flexion angle increased from 10° to 90°. Further, flexing the knee from 10° to 90° decreased the API of the MM from 20.19±4.22mm to 16.41±5.14mm (p<0.001). MMME showed no significant change between knee flexion angles of 10° and 90°. This study demonstrated that, in cases of MMPRT, the MMPE clearly increases when the knee is flexed to 90°, while MMME does not change. Our results suggest that open MRI examination can be used to evaluate the dynamic position of the posterior MM by scanning the knee as it flexes to 90°. IV: retrospective cohort study. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  14. Collateral ligament strains during knee joint laxity evaluation before and after TKA.

    PubMed

    Delport, Hendrik; Labey, Luc; De Corte, Ronny; Innocenti, Bernardo; Vander Sloten, Jos; Bellemans, Johan

    2013-08-01

    Passive knee stability is provided by the soft tissue envelope. There is consensus among orthopedic surgeons that good outcome in Total Knee Arthroplasty requires equal tension in the medial/lateral compartment of the knee joint, as well as equal tension in the flexion/extension gap. The purpose of this study was to quantify the ligament laxity in the normal non-arthritic knee before and after Posterior-Stabilized Total Knee Arthroplasty. We hypothesized that the Medial/Lateral Collateral Ligament shows minimal changes in length when measured directly by extensometers in the native human knee during varus/valgus laxity testing. We also hypothesized that due to differences in material properties and surface geometry, native laxity is difficult to reconstruct using a Posterior-Stabilized Total Knee. Six specimens were used to perform this in vitro cadaver test using extensometers to provide numerical values for laxity and varus-valgus tilting in the frontal plane. This study enabled a precise measurement of varus-valgus laxity as compared with the clinical assessment. The strains in both ligaments in the replaced knee were different from those in the native knee. Both ligaments were stretched in extension, in flexion the Medial Collateral Ligament tends to relax and the Lateral Collateral Ligament remains tight. As material properties and surface geometry of the replaced knee add stiffness to the joint, we recommend to avoid overstuffing the joint, when using this type of Posterior-Stabilized Total Knee Arthroplasty, in order to obtain varus/valgus laxity close to the native joint. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Downregulation of the posterior medial frontal cortex prevents social conformity.

    PubMed

    Klucharev, Vasily; Munneke, Moniek A M; Smidts, Ale; Fernández, Guillén

    2011-08-17

    We often change our behavior to conform to real or imagined group pressure. Social influence on our behavior has been extensively studied in social psychology, but its neural mechanisms have remained largely unknown. Here we demonstrate that the transient downregulation of the posterior medial frontal cortex by theta-burst transcranial magnetic stimulation reduces conformity, as indicated by reduced conformal adjustments in line with group opinion. Both the extent and probability of conformal behavioral adjustments decreased significantly relative to a sham and a control stimulation over another brain area. The posterior part of the medial frontal cortex has previously been implicated in behavioral and attitudinal adjustments. Here, we provide the first interventional evidence of its critical role in social influence on human behavior.

  16. [Comparative evolution surgical accesses to temporo-mandibular joint].

    PubMed

    Sysoliatin, P G; Novikov, A I; Sysoliatin, S P; Bobylev, N G; Brega, I N

    2007-01-01

    In experiment on 30 corpses of adult people criteria of an operational wound (depth of a wound, a corner of operational action, an axis of operational action, a corner of an inclination of operational action) were studied at preauricularis, intrauricularis, intrauriculo-temporalis and posterior mandibullaris access to temporo-mandibular joint (TMJ). New surgical intrauriculo-temporalis access to the joint is substantrated. On the basis of the analysis of 289 operations at 268 patients the indications to a choice of surgical access were developed at various diseases and damages of TMJ.

  17. optBINS: Optimal Binning for histograms

    NASA Astrophysics Data System (ADS)

    Knuth, Kevin H.

    2018-03-01

    optBINS (optimal binning) determines the optimal number of bins in a uniform bin-width histogram by deriving the posterior probability for the number of bins in a piecewise-constant density model after assigning a multinomial likelihood and a non-informative prior. The maximum of the posterior probability occurs at a point where the prior probability and the the joint likelihood are balanced. The interplay between these opposing factors effectively implements Occam's razor by selecting the most simple model that best describes the data.

  18. Stereotactic probability and variability of speech arrest and anomia sites during stimulation mapping of the language dominant hemisphere.

    PubMed

    Chang, Edward F; Breshears, Jonathan D; Raygor, Kunal P; Lau, Darryl; Molinaro, Annette M; Berger, Mitchel S

    2017-01-01

    OBJECTIVE Functional mapping using direct cortical stimulation is the gold standard for the prevention of postoperative morbidity during resective surgery in dominant-hemisphere perisylvian regions. Its role is necessitated by the significant interindividual variability that has been observed for essential language sites. The aim in this study was to determine the statistical probability distribution of eliciting aphasic errors for any given stereotactically based cortical position in a patient cohort and to quantify the variability at each cortical site. METHODS Patients undergoing awake craniotomy for dominant-hemisphere primary brain tumor resection between 1999 and 2014 at the authors' institution were included in this study, which included counting and picture-naming tasks during dense speech mapping via cortical stimulation. Positive and negative stimulation sites were collected using an intraoperative frameless stereotactic neuronavigation system and were converted to Montreal Neurological Institute coordinates. Data were iteratively resampled to create mean and standard deviation probability maps for speech arrest and anomia. Patients were divided into groups with a "classic" or an "atypical" location of speech function, based on the resultant probability maps. Patient and clinical factors were then assessed for their association with an atypical location of speech sites by univariate and multivariate analysis. RESULTS Across 102 patients undergoing speech mapping, the overall probabilities of speech arrest and anomia were 0.51 and 0.33, respectively. Speech arrest was most likely to occur with stimulation of the posterior inferior frontal gyrus (maximum probability from individual bin = 0.025), and variance was highest in the dorsal premotor cortex and the posterior superior temporal gyrus. In contrast, stimulation within the posterior perisylvian cortex resulted in the maximum mean probability of anomia (maximum probability = 0.012), with large variance

  19. Quantum probability assignment limited by relativistic causality.

    PubMed

    Han, Yeong Deok; Choi, Taeseung

    2016-03-14

    Quantum theory has nonlocal correlations, which bothered Einstein, but found to satisfy relativistic causality. Correlation for a shared quantum state manifests itself, in the standard quantum framework, by joint probability distributions that can be obtained by applying state reduction and probability assignment that is called Born rule. Quantum correlations, which show nonlocality when the shared state has an entanglement, can be changed if we apply different probability assignment rule. As a result, the amount of nonlocality in quantum correlation will be changed. The issue is whether the change of the rule of quantum probability assignment breaks relativistic causality. We have shown that Born rule on quantum measurement is derived by requiring relativistic causality condition. This shows how the relativistic causality limits the upper bound of quantum nonlocality through quantum probability assignment.

  20. The Effects of Posterior Rotator Cuff Cable Tears on Glenohumeral Biomechanics in a Cadaveric Model of the Throwing Shoulder

    PubMed Central

    Photopoulos, Christos Demetris; ElAttrache, Neal S.; Doermann, Alex; Akeda, Masaki; McGarry, Michelle H.; Lee, Thay Q.

    2017-01-01

    Objectives: The rotator cuff cable has been postulated to be the primary load bearing substructure of the superior part of the rotator cuff. Tears of the posterior rotator cable are frequently seen in overhead throwing athletes. Although the biomechanical significance of the anterior rotator cable has been well described, our current understanding of the relevance of the posterior cable is limited. The purpose of this study was to examine how partial-thickness tears and full-thickness tears of the posterior rotator cable would alter glenohumeral biomechanics and kinematics in cadaveric shoulder models. Methods: Eight fresh-frozen cadaveric shoulder specimens were prepared and tested. To simulate the sequence of glenohumeral positions during the throwing motion, specimens were mounted on a custom shoulder testing system with the humerus positioned at 90° of abduction (30° scapular upward rotation, 60° glenohumeral abduction) and tested at 30, 60, 90, and 120 degrees of external rotation. After a circumferential capsulotomy was performed, rotator cuff muscles were loaded based on physiologic cross-sectional area ratios, and testing for each specimen was performed on each the following three conditions: intact posterior cable, partial-thickness (50%) articular-sided posterior cable tear, and full-thickness posterior cable tear. Primary outcome measures tested for each condition under the various degrees of glenohumeral rotation were: 1) anterior and total glenohumeral translation after application of a 30N anterior force; 2) path of glenohumeral articulation; 3) glenohumeral joint force. Results: With a 30N anterior force at 120° of external rotation, there was a significant increase in anterior glenohumeral translation between intact and full-thickness tear specimens (7.28±2.00mm and 17.49±3.75mm, respectively; p<0.05). Similarly, total joint translation at 120° of external rotation significantly increased between intact and full-thickness tear specimens (10

  1. Biomechanical evaluation of the impact of various facet joint lesions on the primary stability of anterior plate fixation in cervical dislocation injuries: a cadaver study: Laboratory investigation.

    PubMed

    Oberkircher, Ludwig; Born, Sebastian; Struewer, Johannes; Bliemel, Christopher; Buecking, Benjamin; Wack, Christina; Bergmann, Martin; Ruchholtz, Steffen; Krüger, Antonio

    2014-10-01

    Injuries of the subaxial cervical spine including facet joints and posterior ligaments are common. Potential surgical treatments consist of anterior, posterior, or anterior-posterior fixation. Because each approach has its advantages and disadvantages, the best treatment is debated. This biomechanical cadaver study compared the effect of different facet joint injuries on primary stability following anterior plate fixation. Fractures and plate fixation were performed on 15 fresh-frozen intact cervical spines (C3-T1). To simulate a translation-rotation injury in all groups, complete ligament rupture and facet dislocation were simulated by dissecting the entire posterior and anterior ligament complex between C-4 and C-5. In the first group, the facet joints were left intact. In the second group, one facet joint between C-4 and C-5 was removed and the other side was left intact. In the third group, both facet joints between C-4 and C-5 were removed. The authors next performed single-level anterior discectomy and interbody grafting using bone material from the respective thoracic vertebral bodies. An anterior cervical locking plate was used for fixation. Continuous loading was performed using a servohydraulic test bench at 2 N/sec. The mean load failure was measured when the implant failed. In the group in which both facet joints were intact, the mean load failure was 174.6 ± 46.93 N. The mean load failure in the second group where only one facet joint was removed was 127.8 ± 22.83 N. In the group in which both facet joints were removed, the mean load failure was 73.42 ± 32.51 N. There was a significant difference between the first group (both facet joints intact) and the third group (both facet joints removed) (p < 0.05, Kruskal-Wallis test). In this cadaver study, primary stability of anterior plate fixation for dislocation injuries of the subaxial cervical spine was dependent on the presence of the facet joints. If the bone in one or both facet joints is damaged

  2. Influence of bi- and tri-compartmental knee arthroplasty on the kinematics of the knee joint

    PubMed Central

    2011-01-01

    Background The cruciate ligaments are important stabilizers of the knee joint and determine joint kinematics in the natural knee and after cruciate retaining arthroplasty. No in vitro data is available to biomechanically evaluate the ability of the anterior cruciate ligament (ACL) to maintain knee joint kinematics after bicruciate-retaining bi-compartmental knee arthroplasty (BKA). Therefore, the objective of the current study was to investigate the kinematics of the natural knee joint, before and after installing bicruciate-retaining BKA and posterior cruciate retaining total knee arthroplasty. Specifically, we incorporated a dynamic knee simulator to simulate weight-bearing flexions on cadaveric knee specimen before and after surgical manipulations. Methods In this cadaveric study we investigated rotational and translational tibiofemoral kinematics during simulated weight-bearing flexions of the intact knee, after bi-compartmental knee arthroplasty (BKA+), after resecting the ACL in BKA (BKA-), and after posterior cruciate retaining total knee arthroplasty (TKA). Results Rotation of BKA+ is closest to the intact knee joint, whereas TKA shows significant differences from 30 to 90 degree of flexion. Within the tested flexion range (15 to 90 degree of flexion), there was no significant difference in the anterior-posterior translation among intact, BKA+, and TKA knees. Resecting the ACL in BKA leads to a significant anterior tibial translation. Conclusions BKA with intact cruciate ligaments resembles rotation and translation of the natural knee during a simulated weight-bearing flexion. It is a suitable treatment option for medial and patellofemoral osteoarthritis with advantages in rotational characteristics compared to TKA. PMID:21272328

  3. Preliminary optical coherence tomography investigation of the temporo-mandibular joint disc

    NASA Astrophysics Data System (ADS)

    Mărcăuteanu, Corina; Demjan, Enikö; Sinescu, Cosmin; Negrutiu, Meda; Motoc, Adrian; Lighezan, Rodica; Vasile, Liliana; Hughes, Mike; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

    2010-02-01

    Aim and objectives. The morphology and position of the temporo-mandibular disc are key issues in the diagnosis and treatment of arthrogenous temporo-mandibular disorders. Magnetic resonance imaging and arthroscopy are used today to identify: flattening of the pars posterior of the disc, perforation and/or adhesions in the pars intermedia of the disc and disc displacements. The present study proposes the investigation of the temporo-mandibular joint disc by optical coherence tomography (OCT). Material and methods. 8 human temporo-mandibular joint discs were harvested from dead subjects, under 40 year of age, and conserved in formalin. They had a normal morphology, with a thicker pars posterior (2,6 mm on the average) and a thinner pars intermedia (1mm on the average). We investigated the disc samples using two different OCT systems: an en-face OCT (time domain (TD)-OCT) system, working at 1300 nm (C-scan and B-scan mode) and a spectral OCT system (a Fourier domain (FD)-OCT) system , working at 840 nm (B-scan mode). Results. The OCT investigation of the temporo-mandibular joint discs revealed a homogeneous microstructure. The longer wavelength of the TD-OCT offers a higher penetration depth (2,5 mm in air), which is important for the analysis of the pars posterior, while the FD-OCT is much faster. Conclusions: OCT is a promising imaging method for the microstructural characterization of the temporo-mandibular disc.

  4. Quantitative in vivo MRI evaluation of lumbar facet joints and intervertebral discs using axial T2 mapping.

    PubMed

    Stelzeneder, David; Messner, Alina; Vlychou, Marianna; Welsch, Goetz H; Scheurecker, Georg; Goed, Sabine; Pieber, Karin; Pflueger, Verena; Friedrich, Klaus M; Trattnig, Siegfried

    2011-11-01

    To assess the feasibility of T2 mapping of lumbar facet joints and intervertebral discs in a single imaging slab and to compare the findings with morphological grading. Sixty lumbar spine segments from 10 low back pain patients and 5 healthy volunteers were examined by axial T2 mapping and morphological MRI at 3.0 Tesla. Regions of interest were drawn on a single slice for the facet joints and the intervertebral discs (nucleus pulposus, anterior and posterior annulus fibrosus). The Weishaupt grading was used for facet joints and the Pfirrmann score was used for morphological disc grading ("normal" vs. "abnormal" discs). The inter-rater agreement was excellent for the facet joint T2 evaluation (r = 0.85), but poor for the morphological Weishaupt grading (kappa = 0.15). The preliminary results show similar facet joint T2 values in segments with normal and abnormal Pfirrmann scores. There was no difference in mean T2 values between facet joints in different Weishaupt grading groups. Facet joint T2 values showed a weak correlation with T2 values of the posterior annulus (r = 0.32) This study demonstrates the feasibility of a combined T2 mapping approach for the facet joints and intervertebral discs using a single axial slab.

  5. Incidence of inadvertent intra-articular lumbar facet joint injection during fluoroscopically guided interlaminar epidural steroid injection.

    PubMed

    Huang, Ambrose J; Palmer, William E

    2012-02-01

    To determine the incidence of inadvertent lumbar facet joint injection during an interlaminar epidural steroid injection (ESI). A total of 686 interlaminar lumbar ESIs were performed from January 1, 2009 to December 31, 2009. Archived images from these cases were retrospectively reviewed on the PACS. Positive cases of inadvertent lumbar facet joint injection were identified by the characteristic sigmoid-shaped contrast pattern projecting over the posterior elements on the lateral view and/or ovoid contrast projecting over the facet joints on the anteroposterior (AP) view. Eight positive events were identified (1.2%). There was no statistically significant gender or lumbar level predilection. In 3/8 of the positive cases (37.5%), the inadvertent facet joint injection was recognized by the operator. The needle was repositioned as a result, and contrast within the posterior epidural space was documented by the end of the procedure. In 5/8 of the positive cases (62.5%), the patients reported an immediate decrease in the presenting pain. The incidence of inadvertent lumbar facet joint injection during an interlaminar epidural steroid injection is low. Recognizing the imaging features of this event permits the operator to redirect the needle tip into the epidural space and/or identify the facet joint(s) as a source of the patient's presenting pain.

  6. Role of high tibial osteotomy in chronic injuries of posterior cruciate ligament and posterolateral corner.

    PubMed

    Savarese, Eugenio; Bisicchia, Salvatore; Romeo, Rocco; Amendola, Annunziato

    2011-03-01

    High tibial osteotomy (HTO) is a surgical procedure used to change the mechanical weight-bearing axis and alter the loads carried through the knee. Conventional indications for HTO are medial compartment osteoarthritis and varus malalignment of the knee causing pain and dysfunction. Traditionally, knee instability associated with varus thrust has been considered a contraindication. However, today the indications include patients with chronic ligament deficiencies and malalignment, because an HTO procedure can change not only the coronal but also the sagittal plane of the knee. The sagittal plane has generally been ignored in HTO literature, but its modification has a significant impact on biomechanics and joint stability. Indeed, decreased posterior tibial slope causes posterior tibia translation and helps the anterior cruciate ligament (ACL)-deficient knee. Vice versa, increased tibial slope causes anterior tibia translation and helps the posterior cruciate ligament (PCL)-deficient knee. A review of literature shows that soft tissue procedures alone are often unsatisfactory for chronic posterior instability if alignment is not corrected. Since limb alignment is the most important factor to consider in lower limb reconstructive surgery, diagnosis and treatment of limb malalignment should not be ignored in management of chronic ligamentous instabilities. This paper reviews the effects of chronic posterior instability and tibial slope alteration on knee and soft tissues, in addition to planning and surgical technique for chronic posterior and posterolateral instability with HTO.

  7. Independent Events in Elementary Probability Theory

    ERIC Educational Resources Information Center

    Csenki, Attila

    2011-01-01

    In Probability and Statistics taught to mathematicians as a first introduction or to a non-mathematical audience, joint independence of events is introduced by requiring that the multiplication rule is satisfied. The following statement is usually tacitly assumed to hold (and, at best, intuitively motivated): If the n events E[subscript 1],…

  8. Isolation and Characterization of Human Mesenchymal Stem Cells From Facet Joints and Interspinous Ligaments.

    PubMed

    Kristjánsson, Baldur; Limthongkul, Worawat; Yingsakmongkol, Wicharn; Thantiworasit, Pattarawat; Jirathanathornnukul, Napaphat; Honsawek, Sittisak

    2016-01-01

    A descriptive in vitro study on isolation and differentiation of human mesenchymal stem cells (MSCs) derived from the facet joints and interspinous ligaments. To isolate cells from the facet joints and interspinous ligaments and investigate their surface marker profile and differentiation potentials. Lumbar spinal canal stenosis and ossification of the posterior longitudinal ligament are progressive conditions characterized by the hypertrophy and ossification of ligaments and joints within the spinal canal. MSCs are believed to play a role in the advancement of these diseases and the existence of MSCs has been demonstrated within the ligamentum flavum and posterior longitudinal ligament. The aim of this study was to investigate whether these cells could also be found within facet joints and interspinous ligaments. Samples were harvested from 10 patients undergoing spinal surgery. The MSCs from facet joints and interspinous ligaments were isolated using direct tissue explant technique. Cell surface antigen profilings were performed via flow cytometry. Their lineage differentiation potentials were analyzed. The facet joints and interspinous ligaments-derived MSCs have the tri-lineage potential to be differentiated into osteogenic, adipogenic, and chondrogenic cells under appropriate inductions. Flow cytometry analysis revealed both cell lines expressed MSCs markers. Both facet joints and interspinous ligaments-derived MSCs expressed marker genes for osteoblasts, adipocytes, and chondrocytes. The facet joints and interspinous ligaments may provide alternative sources of MSCs for tissue engineering applications. The facet joints and interspinous ligaments-derived MSCs are part of the microenvironment of the human ligaments of the spinal column and might play a crucial role in the development and progression of degenerative spine conditions.

  9. Reliability-based design optimization using a generalized subset simulation method and posterior approximation

    NASA Astrophysics Data System (ADS)

    Ma, Yuan-Zhuo; Li, Hong-Shuang; Yao, Wei-Xing

    2018-05-01

    The evaluation of the probabilistic constraints in reliability-based design optimization (RBDO) problems has always been significant and challenging work, which strongly affects the performance of RBDO methods. This article deals with RBDO problems using a recently developed generalized subset simulation (GSS) method and a posterior approximation approach. The posterior approximation approach is used to transform all the probabilistic constraints into ordinary constraints as in deterministic optimization. The assessment of multiple failure probabilities required by the posterior approximation approach is achieved by GSS in a single run at all supporting points, which are selected by a proper experimental design scheme combining Sobol' sequences and Bucher's design. Sequentially, the transformed deterministic design optimization problem can be solved by optimization algorithms, for example, the sequential quadratic programming method. Three optimization problems are used to demonstrate the efficiency and accuracy of the proposed method.

  10. Annular and central heavy pigment deposition on the posterior lens capsule in the pigment dispersion syndrome: pigment deposition on the posterior lens capsule in the pigment dispersion syndrome.

    PubMed

    Turgut, Burak; Türkçüoğlu, Peykan; Deniz, Nurettin; Catak, Onur

    2008-12-01

    To report annular and central heavy pigment deposition on the posterior lens capsule in a case of pigment dispersion syndrome. Case report. A 36-year-old female with bilateral pigment dispersion syndrome presented with progressive decrease in visual acuity in the right eye over the past 1-2 years. Clinical examination revealed the typical findings of pigment dispersion syndrome including bilateral Krunkenberg spindles, iris transillumination defects, and dense trabecular meshwork pigmentation. Remarkably, annular and central dense pigmentation of the posterior lens capsule was noted in the right eye. Annular pigment deposition on the posterior lens capsule may be a rare finding associated with pigment dispersion syndrome. Such a finding suggests that there may be aqueous flow into the retrolental space in some patients with this condition. The way of central pigmentation is the entrance of aqueous to Berger's space. In our case, it is probable that spontaneous detachment of the anterior hyaloid membrane aided this entrance.

  11. Demonstration of movement in the sacroiliac joint using ultrasound

    NASA Astrophysics Data System (ADS)

    Krupinski, Elizabeth A.; Brooks, William J.; Lund, Pamela J.

    1995-05-01

    The goal of this study was to demonstrate quantitatively, using ultrasound (US) recording techniques, the extent of motion of the sacroiliac joint achieved using manual medicine techniques. Initial judgements of perceived (i.e., felt) SI mobility during manual examination were made on 22 subjects. Baseline no movement ultrasound images (static) were obtained of the left and right SI joints at two levels-- posterior-superior-iliac-spine and inferior (PSIS, INF)--and two projections (AP and LAT). Manual medicine spring testing of the SI joint was then performed while ultrasound recordings (on video) were made. The differences between baseline separation of the SI joint and displacement distance during spring testing were measured by six radiologists who typically read US images. Significant movement of at least one SI joint was demonstrated in 91% of the subjects using ultrasound recordings. The extent of movement appeared to corroborate the experience of manual medicine practitioners.

  12. Central posterior capsule pigmentation in a patient with pigment dispersion and previous ocular trauma: a case report.

    PubMed

    Al-Mezaine, Hani S

    2010-01-01

    We report a 55-year-old man with unusually dense, unilateral central posterior capsule pigmentation associated with the characteristic clinical features of pigment dispersion syndrome, including a Krukenberg's spindle and dense trabecular pigmentation in both eyes. A history of an old blunt ocular trauma probably caused separation of the anterior hyaloid from the back of the lens, thereby creating an avenue by which pigment could reach the potential space of Berger's from the posterior chamber.

  13. Measurement of glenohumeral joint translation using real-time ultrasound imaging: A physiotherapist and sonographer intra-rater and inter-rater reliability study.

    PubMed

    Rathi, Sangeeta; Taylor, Nicholas F; Gee, Jamie; Green, Rodney A

    2016-12-01

    Ultrasonography is an economical and non-invasive method for measuring real-time joint movements. Although physiotherapists are increasingly using ultrasound imaging for rotator cuff disorders, there is a lack of evidence on their reliability in using ultrasonography to measure glenohumeral translation. The aim of this study was to evaluate the reliability of a physiotherapist in measuring anterior and posterior glenohumeral joint translation with ultrasound. Study design: within day reliability. Anterior and posterior glenohumeral translations were measured at rest, in response to passive accessory motion testing force, and with isometric internal and external rotation in 12 young healthy adults. All the measurements were made in real time by a physiotherapist and an experienced sonographer in two positions (neutral and abducted) and in two views (anterior and posterior). Intra-rater and inter-rater reliability were expressed using intraclass correlation coefficients (ICC) and measurement error (mm). Intra-rater reliability was good for both raters (ICC P : 0.86-0.98; ICC S : 0.85-0.96). The inter-rater reliability between the physiotherapist and sonographer was moderate to good for posterior measurements (ICC 0.50-0.75) and poor to moderate for anterior measurements (ICC 0.31-0.53). For both intra-rater and inter-rater measurements, posterior translation was more reliable than the anterior translation with smaller measurement errors (posterior: 0.1-0.2 mm, anterior: 0.2-0.3 mm). A physiotherapist with minimal training was reliable in measuring glenohumeral joint translations. The ultrasound method was reliable for repeated measurement of both anterior and posterior glenohumeral translations with posterior measurements being more reliable than anterior. This method is recommended for future research to investigate the stabilising role of rotator cuff muscles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Nonstationary envelope process and first excursion probability.

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.

    1972-01-01

    The definition of stationary random envelope proposed by Cramer and Leadbetter, is extended to the envelope of nonstationary random process possessing evolutionary power spectral densities. The density function, the joint density function, the moment function, and the crossing rate of a level of the nonstationary envelope process are derived. Based on the envelope statistics, approximate solutions to the first excursion probability of nonstationary random processes are obtained. In particular, applications of the first excursion probability to the earthquake engineering problems are demonstrated in detail.

  15. Intra-articular calcaneal fractures: effect of open reduction and internal fixation on the contact characteristics of the subtalar joint.

    PubMed

    Mulcahy, D M; McCormack, D M; Stephens, M M

    1998-12-01

    Intra-articular calcaneal fractures are associated with significant long-term morbidity, and considerable controversy exists regarding the optimum method of treating them. The contact characteristics in the intact subtalar joint were determined at known loads and for different positions of the ankle and subtalar joint, using pressure-sensitive film (Super Low; Fuji, Itochu Canada Ltd, Montreal, Quebec). We measured the contact area to joint area ratio (pressure > 5 kg force/cm2 [kgf/cm2]) which normalizes for differences in joint size and the ratio of high pressure zone (>20 kgf/cm2) as a reflection of overall increase in joint pressure. Three simulated fracture patterns were then created and stabilized with either 1 or 2 mm of articular incongruity. Eight specimens were prepared with a primary fracture line through the posterior facet, eight with a joint depression-type fracture, and six with a central joint depression fracture. A measure of 1 to 2 mm of incongruity in the posterior facet for all three fracture patterns produced significant unloading of the depressed fragment, with a redistribution of the overall pattern of pressure distribution to parts of the facet that were previously unloaded.

  16. Artificial atlanto-odontoid joint replacement through a transoral approach.

    PubMed

    Lu, Bin; He, Xi Jing; Zhao, Chen Guang; Li, Hao Peng; Wang, Dong

    2009-01-01

    Resection of the odontoid process and anterior arch of the atlas results in atlantoaxial instability, which if left uncorrected may lead to severe neurological complications. Currently, such atlantoaxial instability is corrected by anterior and/or posterior C1-C2 fusion. However, this results in considerable loss of rotation function of the atlantoaxial complex. From the viewpoint of retaining the rotation function and providing stability, we designed an artificial atlanto-odontoid joint based on anatomical measurements of 50 pairs of dry atlantoaxial specimens by digital calipers and 10 fresh cadaveric specimens by microsurgical techniques. The metal-on-metal titanium alloy joint has an arc-shaped atlas component, and a hollow cylindrical bushing into which fits a rotation axle of an inverted v-shaped axis component and is implanted through a transoral approach. After the joint was implanted onto specimens with anterior decompression, biomechanical tests were performed to compare the stability parameters in the intact state, after decompression, after artificial joint replacement, and after fatigue test. Compared to the intact state, artificial joint replacement resulted in a significant decrease in the range of motion (ROM) and neutral zone (NZ) during flexion, extension, and lateral bending (P < 0.001); however, with regard to axial rotation, there was no significant difference in ROM (P = 0.405), a significant increase in NZ (P = 0.008), and a significant decrease in stiffness (P = 0.003). Compared to the decompressed state, artificial joint replacement resulted in a significantly decreased ROM (P B 0.021) and NZ (P B 0.002) and a significantly increased stiffness (P \\ 0.001) in all directions. Following artificial joint replacement, there was no significant difference in ROM (P C 0.719), NZ (P C 0.580), and stiffness (P C 0.602) in all directions before and after the fatigue test. The artificial joint showed no signs of wear and tear after the fatigue test

  17. Artificial atlanto-odontoid joint replacement through a transoral approach

    PubMed Central

    Lu, Bin; Zhao, Chen Guang; Li, Hao Peng; Wang, Dong

    2008-01-01

    Resection of the odontoid process and anterior arch of the atlas results in atlantoaxial instability, which if left uncorrected may lead to severe neurological complications. Currently, such atlantoaxial instability is corrected by anterior and/or posterior C1–C2 fusion. However, this results in considerable loss of rotation function of the atlantoaxial complex. From the viewpoint of retaining the rotation function and providing stability, we designed an artificial atlanto-odontoid joint based on anatomical measurements of 50 pairs of dry atlantoaxial specimens by digital calipers and 10 fresh cadaveric specimens by microsurgical techniques. The metal-on-metal titanium alloy joint has an arc-shaped atlas component, and a hollow cylindrical bushing into which fits a rotation axle of an inverted v-shaped axis component and is implanted through a transoral approach. After the joint was implanted onto specimens with anterior decompression, biomechanical tests were performed to compare the stability parameters in the intact state, after decompression, after artificial joint replacement, and after fatigue test. Compared to the intact state, artificial joint replacement resulted in a significant decrease in the range of motion (ROM) and neutral zone (NZ) during flexion, extension, and lateral bending (P < 0.001); however, with regard to axial rotation, there was no significant difference in ROM (P = 0.405), a significant increase in NZ (P = 0.008), and a significant decrease in stiffness (P = 0.003). Compared to the decompressed state, artificial joint replacement resulted in a significantly decreased ROM (P ≤ 0.021) and NZ (P ≤ 0.002) and a significantly increased stiffness (P < 0.001) in all directions. Following artificial joint replacement, there was no significant difference in ROM (P ≥ 0.719), NZ (P ≥ 0.580), and stiffness (P ≥ 0.602) in all directions before and after the fatigue test. The artificial joint showed no signs of wear and

  18. Central posterior capsule pigmentation in a patient with pigment dispersion and previous ocular trauma: A case report

    PubMed Central

    Al-Mezaine, Hani S

    2010-01-01

    We report a 55-year-old man with unusually dense, unilateral central posterior capsule pigmentation associated with the characteristic clinical features of pigment dispersion syndrome, including a Krukenberg's spindle and dense trabecular pigmentation in both eyes. A history of an old blunt ocular trauma probably caused separation of the anterior hyaloid from the back of the lens, thereby creating an avenue by which pigment could reach the potential space of Berger's from the posterior chamber. PMID:20534930

  19. Deep convolutional networks for automated detection of posterior-element fractures on spine CT

    NASA Astrophysics Data System (ADS)

    Roth, Holger R.; Wang, Yinong; Yao, Jianhua; Lu, Le; Burns, Joseph E.; Summers, Ronald M.

    2016-03-01

    Injuries of the spine, and its posterior elements in particular, are a common occurrence in trauma patients, with potentially devastating consequences. Computer-aided detection (CADe) could assist in the detection and classification of spine fractures. Furthermore, CAD could help assess the stability and chronicity of fractures, as well as facilitate research into optimization of treatment paradigms. In this work, we apply deep convolutional networks (ConvNets) for the automated detection of posterior element fractures of the spine. First, the vertebra bodies of the spine with its posterior elements are segmented in spine CT using multi-atlas label fusion. Then, edge maps of the posterior elements are computed. These edge maps serve as candidate regions for predicting a set of probabilities for fractures along the image edges using ConvNets in a 2.5D fashion (three orthogonal patches in axial, coronal and sagittal planes). We explore three different methods for training the ConvNet using 2.5D patches along the edge maps of `positive', i.e. fractured posterior-elements and `negative', i.e. non-fractured elements. An experienced radiologist retrospectively marked the location of 55 displaced posterior-element fractures in 18 trauma patients. We randomly split the data into training and testing cases. In testing, we achieve an area-under-the-curve of 0.857. This corresponds to 71% or 81% sensitivities at 5 or 10 false-positives per patient, respectively. Analysis of our set of trauma patients demonstrates the feasibility of detecting posterior-element fractures in spine CT images using computer vision techniques such as deep convolutional networks.

  20. Poster error probability in the Mu-11 Sequential Ranging System

    NASA Technical Reports Server (NTRS)

    Coyle, C. W.

    1981-01-01

    An expression is derived for the posterior error probability in the Mu-2 Sequential Ranging System. An algorithm is developed which closely bounds the exact answer and can be implemented in the machine software. A computer simulation is provided to illustrate the improved level of confidence in a ranging acquisition using this figure of merit as compared to that using only the prior probabilities. In a simulation of 20,000 acquisitions with an experimentally determined threshold setting, the algorithm detected 90% of the actual errors and made false indication of errors on 0.2% of the acquisitions.

  1. Measurement of varus-valgus and internal-external rotational knee laxities in vivo--Part II: relationship with anterior-posterior and general joint laxity in males and females.

    PubMed

    Shultz, Sandra J; Shimokochi, Yohei; Nguyen, Anh-Dung; Schmitz, Randy J; Beynnon, Bruce D; Perrin, David H

    2007-08-01

    We examined sex differences in general joint laxity (GJL), and anterior-posterior displacement (ANT-POST), varus-valgus rotation (VR-VL), and internal-external rotation (INT-EXT) knee laxities, and determined whether greater ANT and GJL predicted greater VR-VL and INT-EXT. Twenty subjects were measured for GJL, and scored on a scale of 0-9. ANT and POST were measured using a standard knee arthrometer at 133 N. VR-VL and INT-EXT were measured using a custom joint laxity testing device, defined as the angular displacements (deg) of the tibia relative to the femur produced by 0-10 Nm of varus-valgus torques, and 0-5 Nm of internal-external torques, respectively. INT-EXT were measured during both non-weight-bearing (NWB) and weight-bearing (WB = 40% body weight) conditions while VR-VL were measured NWB. All laxity measures were greater for females compared to males except for POST. ANT and GJL positively predicted 62.5% of the variance in VR-VL and 41.8% of the variance in WB INT-EXT. ANT was the sole predictor of INT-EXT in NWB, explaining 42.3% of the variance. These findings suggest that subjects who score higher on clinical measures of GJL and ANT are also likely to have greater VR-VL and INT-EXT knee laxities.

  2. Intervals for posttest probabilities: a comparison of 5 methods.

    PubMed

    Mossman, D; Berger, J O

    2001-01-01

    Several medical articles discuss methods of constructing confidence intervals for single proportions and the likelihood ratio, but scant attention has been given to the systematic study of intervals for the posterior odds, or the positive predictive value, of a test. The authors describe 5 methods of constructing confidence intervals for posttest probabilities when estimates of sensitivity, specificity, and the pretest probability of a disorder are derived from empirical data. They then evaluate each method to determine how well the intervals' coverage properties correspond to their nominal value. When the estimates of pretest probabilities, sensitivity, and specificity are derived from more than 80 subjects and are not close to 0 or 1, all methods generate intervals with appropriate coverage properties. When these conditions are not met, however, the best-performing method is an objective Bayesian approach implemented by a simple simulation using a spreadsheet. Physicians and investigators can generate accurate confidence intervals for posttest probabilities in small-sample situations using the objective Bayesian approach.

  3. Data analysis in emission tomography using emission-count posteriors

    NASA Astrophysics Data System (ADS)

    Sitek, Arkadiusz

    2012-11-01

    A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography.

  4. Posterior microphthalmos pigmentary retinopathy syndrome.

    PubMed

    Pehere, Niranjan; Jalali, Subhadra; Deshmukh, Himanshu; Kannabiran, Chitra

    2011-04-01

    Posterior Microphthalmos Pigmentary Retinopathy Syndrome (PMPRS). Posterior microphthalmos (PM) is a relatively infrequent type of microphthalmos where posterior segment is predominantly affected with normal anterior segment measurements. Herein, we report two siblings with posterior microphthalmos retinopathy syndrome with postulated autosomal recessive mode of inheritance. A 13-year-old child had PM and retinitis pigmentosa (RP) and his 7-year-old sister had PM, RP, and foveoschisis. The genetics of this syndrome and variable phenotype is discussed. Importance of being aware of posterior microphthalmos and its posterior segment associations is highlighted.

  5. Simulation of in vivo dynamics during robot assisted joint movement.

    PubMed

    Bobrowitsch, Evgenij; Lorenz, Andrea; Wülker, Nikolaus; Walter, Christian

    2014-12-16

    Robots are very useful tools in orthopedic research. They can provide force/torque controlled specimen motion with high repeatability and precision. A method to analyze dissipative energy outcome in an entire joint was developed in our group. In a previous study, a sheep knee was flexed while axial load remained constant during the measurement of dissipated energy. We intend to apply this method for the investigation of osteoarthritis. Additionally, the method should be improved by simulation of in vivo knee dynamics. Thus, a new biomechanical testing tool will be developed for analyzing in vitro joint properties after different treatments. Discretization of passive knee flexion was used to construct a complex flexion movement by a robot and simulate altering axial load similar to in vivo sheep knee dynamics described in a previous experimental study. The robot applied an in vivo like axial force profile with high reproducibility during the corresponding knee flexion (total standard deviation of 0.025 body weight (BW)). A total residual error between the in vivo and simulated axial force was 0.16 BW. Posterior-anterior and medio-lateral forces were detected by the robot as a backlash of joint structures. Their curve forms were similar to curve forms of corresponding in vivo measured forces, but in contrast to the axial force, they showed higher total standard deviation of 0.118 and 0.203 BW and higher total residual error of 0.79 and 0.21 BW for posterior-anterior and medio-lateral forces respectively. We developed and evaluated an algorithm for the robotic simulation of complex in vivo joint dynamics using a joint specimen. This should be a new biomechanical testing tool for analyzing joint properties after different treatments.

  6. [A new type sternoclavicular hook plate for unstable sternoclavicular joint dislocation and fracture].

    PubMed

    Zhang, Chuan-Yi; Lin, Lie; Liang, Jun-Bo; Wang, Bin; Chen, Guo-Fu; Chen, Hai-Xiao

    2016-11-25

    To evaluate the therapeutic effect of a new type sternoclavicular hook plate fixation in treating unstable sternoclavicular joint dislocation and fracture. From June 2011 to December 2013, 32 patients with sternoclavicular joint dislocation and fracture were treated with a new type sternoclavicular hook plate fixation, including 24 males and 8 females with an average age of 42 years ranging from 25 to 76 years;12 patients were anterior dislocation, 5 pations were posterior dislocation, 10 patients were internal extremity of clavicle fracture and 5 patients were sternoclavicular joint dislocation combined with fracture. The anterior fracture dislocation of the sternoclavicular joint adopted standard sternoclavicular joint hook plate, and the posterior dislocation was at the distal end of the hook of the steel plate, that is, the front part of the handle of the breast was added with a nut and a gasket to prevent the re-dislocation after operation. The results were evaluated according to Rockwood score. No complication happened in all patients. X-ray and CT showed that the dislocation and fracture of the sternoclavicular joint was well reduced and the plate was on right position. All patients were followed up for 6 to 24 months with an average of 10 months. At 6 to 3 months after operation, the fracture was healing without re-dislocation of the sternoclavicular joint, the medial end of the clavicle anatomical structure were restored, functional satisfaction, in which 9 patients with the swelling around sternoclavicular joint, but no pain and other symptoms. The total Rockwood score was 12.78±1.43; the results were excellent in 24 cases, good in 8 cases. The use of the new type of locking hook plate for the treatment of unstable fracture of the sternoclavicular joint, internal fixation is reliable, high security, easy to operate, to provide a reliable method for the treatment of such trauma.

  7. Viral posterior uveitis

    PubMed Central

    Lee, Joanne H.; Agarwal, Aniruddha; Mahendradas, Padmamalini; Lee, Cecilia S.; Gupta, Vishali; Pavesio, Carlos E.; Agrawal, Rupesh

    2017-01-01

    The causes of posterior uveitis can be divided into infectious, autoimmune, or masquerade syndromes. Viral infections, a significant cause of sight-threatening ocular diseases in the posterior segment, include human herpesviruses, measles, rubella, and arboviruses such as dengue, West Nile, and chikungunya virus. Viral posterior uveitis may occur as an isolated ocular disease in congenital or acquired infections or as part of a systemic viral illness. Many viruses remain latent in the infected host with a risk of reactivation that depends on various factors, including virulence and host immunity, age, and comorbidities. Although some viral illnesses are self-limiting and have a good visual prognosis, others, such as cytomegalovirus retinitis or acute retinal necrosis, may result in serious complications and profound vision loss. Since some of these infections may respond well to antiviral therapy, it is important to work up all cases of posterior uveitis to rule out an infectious etiology. We review the clinical features, diagnostic tools, treatment regimens, and long-term outcomes for each of these viral posterior uveitides. PMID:28012878

  8. Glenohumeral joint translation and muscle activity in patients with symptomatic rotator cuff pathology: An ultrasonographic and electromyographic study with age-matched controls.

    PubMed

    Rathi, Sangeeta; Taylor, Nicholas F; Soo, Brendan; Green, Rodney A

    2018-03-02

    To determine whether patients with symptomatic rotator cuff pathology had more glenohumeral joint translation and different patterns of rotator cuff muscle activity compared to controls. Repeated measurements of glenohumeral translation and muscle activity in two positions and six testing conditions in two groups. Twenty participants with a symptomatic and diagnosed rotator cuff tear and 20 age, and gender matched controls were included. Neuromuscular activity was tested by inserting intramuscular electrodes in the rotator cuff muscles. Anterior and posterior glenohumeral translations were measured using real time ultrasound in testing conditions (with and without translation force, with and without isometric internal and external rotation), in two positions (shoulder neutral, 90° of abduction) and two force directions (anterior, posterior). Symptomatic pathology group demonstrated increased passive glenohumeral translation with posterior translation force (p<0.05). Overall, rotator cuff muscle contraction in the pathology group limited joint translation in a similar manner to the control group, but they did not show the normal direction specific pattern in the neutral posterior position (p<0.03). The pathology group demonstrated reduced EMG activity in the upper infraspinatus muscle relative to the reference position (p<0.02) with anterior translation force and in the supraspinatus (p<0.05) muscle with anterior and posterior translation force in the abducted position. Symptomatic pathology resulted in increased passive glenohumeral joint translation. Although there were some reductions in muscle activity with injury, their rotator cuff still controlled glenohumeral translation. These results highlight the need to consider joint translation in the assessment and management of patients with rotator cuff injury. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  9. Soft tissue balance changes depending on joint distraction force in total knee arthroplasty.

    PubMed

    Nagai, Kanto; Muratsu, Hirotsugu; Matsumoto, Tomoyuki; Miya, Hidetoshi; Kuroda, Ryosuke; Kurosaka, Masahiro

    2014-03-01

    The influence of joint distraction force on intraoperative soft tissue balance was evaluated using Offset Repo-Tensor® for 78 knees that underwent primary posterior-stabilized total knee arthroplasty. The joint center gap and varus ligament balance were measured between osteotomized surfaces using 20, 40 and 60 lbs of joint distraction force. These values were significantly increased at extension and flexion as the distraction force increased. Furthermore, lateral compartment stiffness was significantly lower than medial compartment stiffness. Thus, larger joint distraction forces led to larger varus ligament balance and joint center gap, because of the difference in soft tissue stiffness between lateral and medial compartments. These findings indicate the importance of the strength of joint distraction force in the assessment of soft tissue balance, especially when using gap-balancing technique. © 2014.

  10. [MINIMALLY INVASIVE TREATMENT OF POSTERIOR CRUCIATE LIGAMENT AVULSION FRACTURE IN A FLOPPY LATERAL POSITION].

    PubMed

    Zhao, Junchao; Wang, Hao

    2016-09-08

    To conclude the effectiveness of arthroscopy combined with Burks and SchaVer's approach in the treatment of posterior cruciate ligament (PCL) avulsion fractures in a floppy lateral position. Between May 2010 and March 2014, 21 patients with PCL avulsion fractures were treated. There were 13 males and 8 females, aged 21 to 62 years (mean, 39.1 years). The causes included traffic accident injury in 10 cases, sports injury in 5 cases, and falling injury from height in 6 cases. The time from injury to hospital was 1-6 days (mean, 2.5 days). The results of posterior drawer test were all positive, and the results of anterior drawer test and lateral stress test were all negative. The Lysholm score was 28.0±5.5 before operation. And the American Orthopaedic Foot and Ankle Society (IKDC) score was 46.2±7.6 before operation. According to Meyer standards for fractures classification, 11 cases were rated as type II and 10 cases as type III. Arthroscopy was used to inspect and treat the intra-articular lesions, then avulsion fracture was fixed by Burks and SchaVer's approach in lateral position. Postoperative functional exercises were performed. Primary healing of incision was obtained, without nerve and vascular injury or joint infection. All patients were followed up 18-36 months (mean, 27.2 months). The X-ray films of the knee joint showed good fractures reduction and healing at 3 months after operation. The results of posterior drawer test and reverse Lachman test were negative. The knee range of motion was recovered to normal level. At last follow-up, the Lysholm score of the knee joint was significantly improved to 90.9±1.4 from preoperative one ( t =54.584, P =0.000), and the IKDC score was significantly increased to 90.5±5.3 from preoperative one ( t =15.638, P =0.000), including 19 cases of grade A and 2 cases of grade B. A combination of arthroscopy and Burks and SchaVer's approach for the treatment of PCL avulsion fractures in a floppy lateral position has the

  11. Anatomy and classification of the posterior tibial fragment in ankle fractures.

    PubMed

    Bartoníček, Jan; Rammelt, Stefan; Kostlivý, Karel; Vaněček, Václav; Klika, Daniel; Trešl, Ivo

    2015-04-01

    The aim of this study was to analyze the pathoanatomy of the posterior fragment on the basis of a comprehensive CT examination, including 3D reconstructions, in a large patient cohort. One hundred and forty one consecutive individuals with an ankle fracture or fracture-dislocation of types Weber B or Weber C and evidence of a posterior tibial fragment in standard radiographs were included in the study. The mean patient age was 49 years (range 19-83 years). The exclusion criteria were patients below 18 years of age, inability to provide written consent, fractures of the tibial pilon, posttraumatic arthritis and pre-existing deformities. In all patients, post-injury radiographs were obtained in anteroposterior, mortise and lateral views. All patients underwent CT scanning in transverse, sagittal and frontal planes. 3D CT reconstruction was performed in 91 patients. We were able to classify 137 cases into one of the following four types with constant pathoanatomic features: type 1: extraincisural fragment with an intact fibular notch, type 2: posterolateral fragment extending into the fibular notch, type 3: posteromedial two-part fragment involving the medial malleolus, type 4: large posterolateral triangular fragment. In the 4 cases it was not possible to classify the type of the posterior tibial fragment. These were collectively termed type 5 (irregular, osteoporotic fragments). It is impossible to assess the shape and size of the posterior malleolar fragment, involvement of the fibular notch, or the medial malleolus, on the basis of plain radiographs. The system that we propose for classification of fractures of the posterior malleolus is based on CT examination and takes into account the size, shape and location of the fragment, stability of the tibio-talar joint and the integrity of the fibular notch. It may be a useful indication for surgery and defining the most useful approach to these injuries.

  12. Arthroscopic Management of Anterior, Posterior, and Multidirectional Shoulder Instabilities.

    PubMed

    Field, Larry D; Ryu, Richard K N; Abrams, Jeffrey S; Provencher, Matthew

    2016-01-01

    Arthroscopic shoulder stabilization offers several potential advantages compared with open surgery, including the opportunity to more accurately evaluate the glenohumeral joint at the time of diagnostic assessment; comprehensively address multiple pathologic lesions that may be identified; and avoid potential complications unique to open stabilization, such as postoperative subscapularis failure. A thorough understanding of normal shoulder anatomy and biomechanics, along with the pathoanatomy responsible for anterior, posterior, and multidirectional shoulder instability patterns, is very important in the management of patients who have shoulder instability. The treating physician also must be familiar with diagnostic imaging and physical examination maneuvers that are required to accurately diagnose shoulder instability.

  13. A new technique for repair of a dislocated sternoclavicular joint using a sternal tension cable system.

    PubMed

    Janson, Jacques T; Rossouw, Gawie J

    2013-02-01

    An unstable anterior or posterior sternoclavicular joint dislocation can cause severe morbidity with poor shoulder movement and strength. These dislocations need to be repaired, which can be challenging. Many different procedures have been described to obtain a stable joint fixation with varying results. We report a new technique for repairing a sternoclavicular joint dislocation by using a figure-of-eight sternal cable system. This procedure is relatively simple and reproducible to create a stable and functional sternoclavicular joint. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  14. The perception of probability.

    PubMed

    Gallistel, C R; Krishan, Monika; Liu, Ye; Miller, Reilly; Latham, Peter E

    2014-01-01

    We present a computational model to explain the results from experiments in which subjects estimate the hidden probability parameter of a stepwise nonstationary Bernoulli process outcome by outcome. The model captures the following results qualitatively and quantitatively, with only 2 free parameters: (a) Subjects do not update their estimate after each outcome; they step from one estimate to another at irregular intervals. (b) The joint distribution of step widths and heights cannot be explained on the assumption that a threshold amount of change must be exceeded in order for them to indicate a change in their perception. (c) The mapping of observed probability to the median perceived probability is the identity function over the full range of probabilities. (d) Precision (how close estimates are to the best possible estimate) is good and constant over the full range. (e) Subjects quickly detect substantial changes in the hidden probability parameter. (f) The perceived probability sometimes changes dramatically from one observation to the next. (g) Subjects sometimes have second thoughts about a previous change perception, after observing further outcomes. (h) The frequency with which they perceive changes moves in the direction of the true frequency over sessions. (Explaining this finding requires 2 additional parametric assumptions.) The model treats the perception of the current probability as a by-product of the construction of a compact encoding of the experienced sequence in terms of its change points. It illustrates the why and the how of intermittent Bayesian belief updating and retrospective revision in simple perception. It suggests a reinterpretation of findings in the recent literature on the neurobiology of decision making. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  15. The utility of Bayesian predictive probabilities for interim monitoring of clinical trials

    PubMed Central

    Connor, Jason T.; Ayers, Gregory D; Alvarez, JoAnn

    2014-01-01

    Background Bayesian predictive probabilities can be used for interim monitoring of clinical trials to estimate the probability of observing a statistically significant treatment effect if the trial were to continue to its predefined maximum sample size. Purpose We explore settings in which Bayesian predictive probabilities are advantageous for interim monitoring compared to Bayesian posterior probabilities, p-values, conditional power, or group sequential methods. Results For interim analyses that address prediction hypotheses, such as futility monitoring and efficacy monitoring with lagged outcomes, only predictive probabilities properly account for the amount of data remaining to be observed in a clinical trial and have the flexibility to incorporate additional information via auxiliary variables. Limitations Computational burdens limit the feasibility of predictive probabilities in many clinical trial settings. The specification of prior distributions brings additional challenges for regulatory approval. Conclusions The use of Bayesian predictive probabilities enables the choice of logical interim stopping rules that closely align with the clinical decision making process. PMID:24872363

  16. Three dimensional finite element analysis of the influence of posterior tibial slope on the anterior cruciate ligament and knee joint forward stability.

    PubMed

    Qi, Yong; Sun, Hongtao; Fan, Yueguang; Li, Feimeng; Wang, Yunting; Ge, Chana

    2018-03-23

    To explore the biomechanical influence of posterior tibial angle on the anterior cruciate ligament and knee joint forward stability. The left knee joint of a healthy volunteer was scanned by CT and MRI. The data were imported into Mimics software to obtain 3D models of bone, cartilage, meniscus and ligament structures, and then Geomagic software was used to modify of the image. The relative displacement between tibia and femur and the stress of ACL were recorded. ACL tension was 12.195 N in model with 2∘ PTS, 12.639 N in model with 7∘ PTS, 18.658 N in model with 12∘ PTS. the relative displacement of the tibia and femur was 2.735 mm in model with 2∘ PTS, 3.086 mm in model with 7∘ PTS, 3.881 mm in model with 12∘ PTS. In the model with 30∘ flexion, the maximum tension of ACL was 24.585 N in model with 2∘ PTS, 25.612 N in model with 7∘ PTS, 31.481 N in model with 12∘ PTS. The relative displacement of the tibia and femur was 5.590 mm in model with 2∘ PTS, 6.721 mm in model with 7∘ PTS, 6.952 mm in model with 12∘ PTS. In the 90∘ flexion models, ACL tension was 5.119 N in model with 2∘ PTS, 8.674 N in model with 7∘ PTS, 9.314 N in model with 12∘ PTS. The relative displacement of the tibia and femur was 0.276 mm in model with 2∘ PTS, 0.577 mm in model with 7∘ PTS, 0.602 mm in model with 12∘ PTS. The steeper PTS may be a risk factor in ACL injury.

  17. Some Simple Formulas for Posterior Convergence Rates

    PubMed Central

    2014-01-01

    We derive some simple relations that demonstrate how the posterior convergence rate is related to two driving factors: a “penalized divergence” of the prior, which measures the ability of the prior distribution to propose a nonnegligible set of working models to approximate the true model and a “norm complexity” of the prior, which measures the complexity of the prior support, weighted by the prior probability masses. These formulas are explicit and involve no essential assumptions and are easy to apply. We apply this approach to the case with model averaging and derive some useful oracle inequalities that can optimize the performance adaptively without knowing the true model. PMID:27379278

  18. Knee joint effusion following ipsilateral hip surgery.

    PubMed

    Christodoulou, A G; Givissis, P; Antonarakos, P D; Petsatodis, G E; Hatzokos, I; Pournaras, J D

    2010-12-01

    To correlate patellar reflex inhibition with sympathetic knee joint effusion. 65 women and 40 men aged 45 to 75 (mean, 65) years underwent hip surgery. The surgery entailed dynamic hip screw fixation using the lateral approach with reflection of the vastus lateralis for pertrochantric fractures (n = 49), and hip hemiarthroplasty or total hip replacement using the Watson-Jones approach (n = 38) or hip hemiarthroplasty using the posterior approach (n = 18) for subcapital femoral fractures (n = 28) or osteoarthritis (n = 28). Knee joint effusion, patellar reflex, and thigh circumference were assessed in both legs before and after surgery (at day 0.5, 2, 7, 14, 30, and 45). Time-sequence plots were used for chronological analysis, and correlation between patellar reflex inhibition and knee joint effusion was tested. In the time-sequence plot, the peak frequency of patellar reflex inhibition (on day 0.5) preceded that of the knee joint effusion and the thigh circumference increase (on day 2). Patellar reflex inhibition correlated positively with the knee joint effusion (r = 0.843, p = 0.035). These 2 factors correlated significantly for all 3 surgical approaches (p < 0.0005). All 3 approaches were associated with patellar reflex inhibition on day 0.5 (p = 0.033) and knee joint effusion on day 2 (p = 0.051). Surgical trauma of the thigh may cause patellar reflex inhibition and subsequently knee joint effusion.

  19. Does joint line elevation after revision knee arthroplasty affect tibio-femoral kinematics, contact pressure or collateral ligament lengths? An in vitro analysis

    PubMed Central

    Kowalczewski, Jacek B.; Chevalier, Yan; Okon, Tomasz; Innocenti, Bernardo; Bellemans, Johan

    2015-01-01

    Introduction Correct restoration of the joint line is generally considered as crucial when performing total knee arthroplasty (TKA). During revision knee arthroplasty however, elevation of the joint line occurs frequently. The general belief is that this negatively affects the clinical outcome, but the reasons are still not well understood. Material and methods In this cadaveric in vitro study the biomechanical consequences of joint line elevation were investigated using a previously validated cadaver model simulating active deep knee squats and passive flexion-extension cycles. Knee specimens were sequentially tested after total knee arthroplasty with joint line restoration and after 4 mm joint line elevation. Results The tibia rotated internally with increasing knee flexion during both passive and squatting motion (range: 17° and 7° respectively). Joint line elevation of 4 mm did not make a statistically significant difference. During passive motion, the tibia tended to become slightly more adducted with increasing knee flexion (range: 2°), while it went into slighlty less adduction during squatting (range: –2°). Neither of both trends was influenced by joint line elevation. Also anteroposterior translation of the femoral condyle centres was not affected by joint line elevation, although there was a tendency for a small posterior shift (of about 3 mm) during squatting after joint line elevation. In terms of kinetics, ligaments lengths and length changes, tibiofemoral contact pressures and quadriceps forces all showed the same patterns before and joint line elevation. No statistically significant changes could be detected. Conclusions Our study suggests that joint line elevation by 4 mm in revision total knee arthroplasty does not cause significant kinematic and kinetic differences during passive flexion/extension movement and squatting in the tibio-femoral joint, nor does it affect the elongation patterns of collateral ligaments. Therefore, clinical

  20. Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: single center experience in treating posterior pelvic instability.

    PubMed

    Fischer, Sebastian; Vogl, Thomas J; Marzi, Ingo; Zangos, Stephan; Wichmann, Julian L; Scholtz, Jan-Erik; Mack, Martin G; Schmidt, Sven; Eichler, Katrin

    2015-02-01

    The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. 100 guidewires and hollow titan screws were inserted in 38 patients (49.6±19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. The mean minimal distance between guidewire and adjacent neural foramina was 4.5±2.01mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6±0.53mm to 1.2±0.54mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7mGycm). The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Joint-layer encoder optimization for HEVC scalable extensions

    NASA Astrophysics Data System (ADS)

    Tsai, Chia-Ming; He, Yuwen; Dong, Jie; Ye, Yan; Xiu, Xiaoyu; He, Yong

    2014-09-01

    Scalable video coding provides an efficient solution to support video playback on heterogeneous devices with various channel conditions in heterogeneous networks. SHVC is the latest scalable video coding standard based on the HEVC standard. To improve enhancement layer coding efficiency, inter-layer prediction including texture and motion information generated from the base layer is used for enhancement layer coding. However, the overall performance of the SHVC reference encoder is not fully optimized because rate-distortion optimization (RDO) processes in the base and enhancement layers are independently considered. It is difficult to directly extend the existing joint-layer optimization methods to SHVC due to the complicated coding tree block splitting decisions and in-loop filtering process (e.g., deblocking and sample adaptive offset (SAO) filtering) in HEVC. To solve those problems, a joint-layer optimization method is proposed by adjusting the quantization parameter (QP) to optimally allocate the bit resource between layers. Furthermore, to make more proper resource allocation, the proposed method also considers the viewing probability of base and enhancement layers according to packet loss rate. Based on the viewing probability, a novel joint-layer RD cost function is proposed for joint-layer RDO encoding. The QP values of those coding tree units (CTUs) belonging to lower layers referenced by higher layers are decreased accordingly, and the QP values of those remaining CTUs are increased to keep total bits unchanged. Finally the QP values with minimal joint-layer RD cost are selected to match the viewing probability. The proposed method was applied to the third temporal level (TL-3) pictures in the Random Access configuration. Simulation results demonstrate that the proposed joint-layer optimization method can improve coding performance by 1.3% for these TL-3 pictures compared to the SHVC reference encoder without joint-layer optimization.

  2. The Effect of Graft Strength on Knee Laxity and Graft In-Situ Forces after Posterior Cruciate Ligament Reconstruction

    PubMed Central

    Lai, Yu-Shu; Chen, Wen-Chuan; Huang, Chang-Hung; Cheng, Cheng-Kung; Chan, Kam-Kong; Chang, Ting-Kuo

    2015-01-01

    Surgical reconstruction is generally recommended for posterior cruciate ligament (PCL) injuries; however, the use of grafts is still a controversial problem. In this study, a three-dimensional finite element model of the human tibiofemoral joint with articular cartilage layers, menisci, and four main ligaments was constructed to investigate the effects of graft strengths on knee kinematics and in-situ forces of PCL grafts. Nine different graft strengths with stiffness ranging from 0% (PCL rupture) to 200%, in increments of 25%, of an intact PCL’s strength were used to simulate the PCL reconstruction. A 100 N posterior tibial drawer load was applied to the knee joint at full extension. Results revealed that the maximum posterior translation of the PCL rupture model (0% stiffness) was 6.77 mm in the medial compartment, which resulted in tibial internal rotation of about 3.01°. After PCL reconstruction with any graft strength, the laxity of the medial tibial compartment was noticeably improved. Tibial translation and rotation were similar to the intact knee after PCL reconstruction with graft strengths ranging from 75% to 125% of an intact PCL. When the graft’s strength surpassed 150%, the medial tibia moved forward and external tibial rotation greatly increased. The in-situ forces generated in the PCL grafts ranged from 13.15 N to 75.82 N, depending on the stiffness. In conclusion, the strength of PCL grafts have has a noticeable effect on anterior-posterior translation of the medial tibial compartment and its in-situ force. Similar kinematic response may happen in the models when the PCL graft’s strength lies between 75% and 125% of an intact PCL. PMID:26001045

  3. The effect of graft strength on knee laxity and graft in-situ forces after posterior cruciate ligament reconstruction.

    PubMed

    Lai, Yu-Shu; Chen, Wen-Chuan; Huang, Chang-Hung; Cheng, Cheng-Kung; Chan, Kam-Kong; Chang, Ting-Kuo

    2015-01-01

    Surgical reconstruction is generally recommended for posterior cruciate ligament (PCL) injuries; however, the use of grafts is still a controversial problem. In this study, a three-dimensional finite element model of the human tibiofemoral joint with articular cartilage layers, menisci, and four main ligaments was constructed to investigate the effects of graft strengths on knee kinematics and in-situ forces of PCL grafts. Nine different graft strengths with stiffness ranging from 0% (PCL rupture) to 200%, in increments of 25%, of an intact PCL's strength were used to simulate the PCL reconstruction. A 100 N posterior tibial drawer load was applied to the knee joint at full extension. Results revealed that the maximum posterior translation of the PCL rupture model (0% stiffness) was 6.77 mm in the medial compartment, which resulted in tibial internal rotation of about 3.01°. After PCL reconstruction with any graft strength, the laxity of the medial tibial compartment was noticeably improved. Tibial translation and rotation were similar to the intact knee after PCL reconstruction with graft strengths ranging from 75% to 125% of an intact PCL. When the graft's strength surpassed 150%, the medial tibia moved forward and external tibial rotation greatly increased. The in-situ forces generated in the PCL grafts ranged from 13.15 N to 75.82 N, depending on the stiffness. In conclusion, the strength of PCL grafts have has a noticeable effect on anterior-posterior translation of the medial tibial compartment and its in-situ force. Similar kinematic response may happen in the models when the PCL graft's strength lies between 75% and 125% of an intact PCL.

  4. Foot segmental motion and coupling in stage II and III tibialis posterior tendon dysfunction.

    PubMed

    Van de Velde, Maarten; Matricali, Giovanni Arnoldo; Wuite, Sander; Roels, Charlotte; Staes, Filip; Deschamps, Kevin

    2017-06-01

    Classification systems developed in the field of posterior tibialis tendon dysfunction omit to include dynamic measurements. Since this may negatively affect the selection of the most appropriate treatment modality, studies on foot kinematics are highly recommended. Previous research characterised the foot kinematics in patients with posterior tibialis tendon dysfunction. However, none of the studies analysed foot segmental motion synchrony during stance phase, nor compared the kinematic behaviour of the foot in presence of different posterior tibialis tendon dysfunction stages. Therefore, we aimed at comparing foot segmental motion and coupling in patients with posterior tibialis tendon dysfunction grade 2 and 3 to those of asymptomatic subjects. Foot segmental motion of 11 patients suffering from posterior tibialis tendon dysfunction stage 2, 4 patients with posterior tibialis tendon dysfunction stage 3 and 15 asymptomatic subjects was objectively quantified with the Rizzoli foot model using an instrumented walkway and a 3D passive motion capture system. Dependent variables were the range of motion occurring at the different inter-segment angles during subphases of stance and swing phase as well as the cross-correlation coefficient between a number of segments. Significant differences in range of motion were predominantly found during the forefoot push off phase and swing phase. In general, both patient cohorts demonstrated a reduced range of motion compared to the control group. This hypomobility occurred predominantly in the rearfoot and midfoot (p<0.01). Significant differences between both posterior tibialis tendon dysfunction patient cohorts were not revealed. Cross-correlation coefficients highlighted a loss of joint coupling between rearfoot and tibia as well as between rearfoot and forefoot in both posterior tibialis tendon dysfunction groups. The current evidence reveals considerable mechanical alterations in the foot which should be considered in the

  5. Probability of spacesuit-induced fingernail trauma is associated with hand circumference.

    PubMed

    Opperman, Roedolph A; Waldie, James M A; Natapoff, Alan; Newman, Dava J; Jones, Jeffrey A

    2010-10-01

    A significant number of astronauts sustain hand injuries during extravehicular activity training and operations. These hand injuries have been known to cause fingernail delamination (onycholysis) that requires medical intervention. This study investigated correlations between the anthropometrics of the hand and susceptibility to injury. The analysis explored the hypothesis that crewmembers with a high finger-to-hand size ratio are more likely to experience injuries. A database of 232 crewmembers' injury records and anthropometrics was sourced from NASA Johnson Space Center. No significant effect of finger-to-hand size was found on the probability of injury, but circumference and width of the metacarpophalangeal (MCP) joint were found to be significantly associated with injuries by the Kruskal-Wallis test. A multivariate logistic regression showed that hand circumference is the dominant effect on the likelihood of onycholysis. Male crewmembers with a hand circumference > 22.86 cm (9") have a 19.6% probability of finger injury, but those with hand circumferences < or = 22.86 cm (9") only have a 5.6% chance of injury. Findings were similar for female crewmembers. This increased probability may be due to constriction at large MCP joints by the current NASA Phase VI glove. Constriction may lead to occlusion of vascular flow to the fingers that may increase the chances of onycholysis. Injury rates are lower on gloves such as the superseded series 4000 and the Russian Orlan that provide more volume for the MCP joint. This suggests that we can reduce onycholysis by modifying the design of the current gloves at the MCP joint.

  6. Effects of medial meniscal posterior horn avulsion and repair on meniscal displacement.

    PubMed

    Hein, Christopher N; Deperio, Jennifer Gurske; Ehrensberger, Mark T; Marzo, John M

    2011-06-01

    Medial meniscal posterior root avulsion (MMRA) leads to deleterious alteration of medial joint compartment loading profiles and increased risk of medial degenerative changes. Surgical repair restores more normal biomechanics to the knee. Our hypothesis is that MMRA will cause medial meniscal (MM) extrusion and gap formation between the root attachment site and MM. Meniscal root repair will restore the ability of the meniscus to resist extrusion, and reduce gap formation at the defect. Seven fresh frozen human cadaveric knees were dissected and mechanically loaded using a servo-hydraulic load frame (MTS ®) with 0 and 1800 N. The knees were tested under three conditions: native, avulsed, and repaired. Four measurements were obtained: meniscal displacement anteriorly, medially, posteriorly, and gap distance between the root attachment site and MM after transection and repair. The medial displacement of the avulsed MM (3.28 mm) was significantly greater (p < 0.001) than the native knee (1.60mm) and repaired knee (1.46 mm). Gap formation is significantly larger in the avulsed compared to repaired state at 0 (p < 0.02) and 1800N (p < 0.02) and also larger with loading in both avulsed (p < 0.05) and repaired (p < 0.02) conditions. Therefore, MMRA results in MM extrusion from the joint and gap formation between the MM root and the MM. Subsequent surgical repair reduces meniscal displacement and gap formation at the defect. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Bayesian bivariate meta-analysis of correlated effects: Impact of the prior distributions on the between-study correlation, borrowing of strength, and joint inferences

    PubMed Central

    Bujkiewicz, Sylwia; Riley, Richard D

    2016-01-01

    Multivariate random-effects meta-analysis allows the joint synthesis of correlated results from multiple studies, for example, for multiple outcomes or multiple treatment groups. In a Bayesian univariate meta-analysis of one endpoint, the importance of specifying a sensible prior distribution for the between-study variance is well understood. However, in multivariate meta-analysis, there is little guidance about the choice of prior distributions for the variances or, crucially, the between-study correlation, ρB; for the latter, researchers often use a Uniform(−1,1) distribution assuming it is vague. In this paper, an extensive simulation study and a real illustrative example is used to examine the impact of various (realistically) vague prior distributions for ρB and the between-study variances within a Bayesian bivariate random-effects meta-analysis of two correlated treatment effects. A range of diverse scenarios are considered, including complete and missing data, to examine the impact of the prior distributions on posterior results (for treatment effect and between-study correlation), amount of borrowing of strength, and joint predictive distributions of treatment effectiveness in new studies. Two key recommendations are identified to improve the robustness of multivariate meta-analysis results. First, the routine use of a Uniform(−1,1) prior distribution for ρB should be avoided, if possible, as it is not necessarily vague. Instead, researchers should identify a sensible prior distribution, for example, by restricting values to be positive or negative as indicated by prior knowledge. Second, it remains critical to use sensible (e.g. empirically based) prior distributions for the between-study variances, as an inappropriate choice can adversely impact the posterior distribution for ρB, which may then adversely affect inferences such as joint predictive probabilities. These recommendations are especially important with a small number of studies and

  8. Effect of the walking speed to the lower limb joint angular displacements, joint moments and ground reaction forces during walking in water.

    PubMed

    Miyoshi, Tasuku; Shirota, Takashi; Yamamoto, Shin-ichiro; Nakazawa, Kimitaka; Akai, Masami

    2004-06-17

    The purpose of this study was to compare the changes in ground reaction forces (GRF), joint angular displacements (JAD), joint moments (JM) and electromyographic (EMG) activities that occur during walking at various speeds in water and on land. Fifteen healthy adults participated in this study. In the water experiments, the water depth was adjusted so that body weight was reduced by 80%. A video-motion analysis system and waterproof force platform was used to obtain kinematics and kinetics data and to calculate the JMs. Results revealed that (1) the anterior-posterior GRF patterns differed between walking in water and walking on land, whereas the medio-lateral GRF patterns were similar, (2) the JAD patterns of the hip and ankle were similar between water- and land-walking, whereas the range of motion at the knee joint was lower in water than on land, (3) the JMs in all three joints were lower in water than on land throughout the stance phase, and (4) the hip joint extension moment and hip extensor muscle EMG activity were increased as walking speed increase during walking in water. Rehabilitative water-walking exercise could be designed to incorporate large-muscle activities, especially of the lower-limb extensor muscles, through full joint range of motion and minimization of joint moments.

  9. The effects of the one-step replica symmetry breaking on the Sherrington-Kirkpatrick spin glass model in the presence of random field with a joint Gaussian probability density function for the exchange interactions and random fields

    NASA Astrophysics Data System (ADS)

    Hadjiagapiou, Ioannis A.; Velonakis, Ioannis N.

    2018-07-01

    The Sherrington-Kirkpatrick Ising spin glass model, in the presence of a random magnetic field, is investigated within the framework of the one-step replica symmetry breaking. The two random variables (exchange integral interaction Jij and random magnetic field hi) are drawn from a joint Gaussian probability density function characterized by a correlation coefficient ρ, assuming positive and negative values. The thermodynamic properties, the three different phase diagrams and system's parameters are computed with respect to the natural parameters of the joint Gaussian probability density function at non-zero and zero temperatures. The low temperature negative entropy controversy, a result of the replica symmetry approach, has been partly remedied in the current study, leading to a less negative result. In addition, the present system possesses two successive spin glass phase transitions with characteristic temperatures.

  10. Immediate effects of manipulation of the talocrural joint on stabilometry and baropodometry in patients with ankle sprain.

    PubMed

    López-Rodríguez, Sandra; Fernández de-Las-Peñas, César; Alburquerque-Sendín, Francisco; Rodríguez-Blanco, Cleofás; Palomeque-del-Cerro, Luis

    2007-01-01

    This study assessed the immediate effects of talocrural joint manipulation on stabilometric and baropodometric outcomes in patients with grade II ankle sprain. Fifty-two field hockey players (35 men and 17 women) between 18 and 40 years old (mean = 22.5 years, SD = 3.6 years) were included in this study. A simple blind, intrapatient, placebo-controlled, and repeated-measures study was carried out. All the patients underwent a baropodometric study performed with a Foot Work force platform (4 times; pre-post placebo group and pre-post intervention group). The sample was subjected to two techniques of manipulative treatment: (a) talocrural joint manipulation and (b) posterior gliding manipulation over the talus. In a second instance, placebo manipulation was applied. Unilateral analysis of variance and multivariate analysis of variance were used for statistical analysis. The results in the intervention group revealed significant differences in the percentage of posterior load on the foot (P = .015) and the percentage of bilateral anterior load (P = .02) before and after the manipulation. The placebo group did not show any change in any of the variables except for area (P = .045). Intergroup comparison revealed statistically significant differences in the increase in percentage of posterior load on the manipulated foot, percentage of bilateral posterior load, percentage of anterior load on the manipulated foot, and percentage of bilateral anterior load (with the exception of the total load on the foot). The application of caudal talocrural joint manipulation, as compared with placebo manipulation, in athletic patients with grade II ankle sprain redistributed the load supports at the level of the foot.

  11. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

    PubMed Central

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  12. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region.

    PubMed

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-11-05

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis.

  13. [Feasibility and accuracy of ultrasound-guided methodology in the examination of lumbar spine facet joints].

    PubMed

    Wen, Chuan-Bing; Li, Yong-Zhong; Tang, Qin-Qin; Sun, Lin; Xiao, Hong; Yang, Bang-Xiang; Song, Li; Liu, Hui

    2013-03-01

    To investigate the feasibility, accuracy of B ultrasound in the examination of joint space of lumbar spine facet joints compared with CT scan. Ten healthy adult volunteers were enrolled. The joint space of lumbar facet joints was measured by ultrasound. To identify the spinal levels, the posterior parasagittal sonograms were obtained at levels L1 to S1. The lumbar facet joints were delineated with the help of transverse sonograms at each level. Meanwhile, the lumbar facet joints were evaluated by spiral CT on the same plane, reformatted to 1-mm axial slices. A total of 88 lumbar facet joints from L1 to S1 were clearly visualized in the 10 volunteers. Both ultrasound and CT measurements showed the same average depth and lateral distance of lumbar facet joint space (P > 0.05). The lumbar facet joint space can be accurately demonstrated by ultrasound.

  14. Application of posterior pelvic tilt taping for the treatment of chronic low back pain with sacroiliac joint dysfunction and increased sacral horizontal angle.

    PubMed

    Lee, Jung-hoon; Yoo, Won-gyu

    2012-11-01

    Kinesio Taping (KT) is a therapeutic method used by physical therapists and athletic trainers in combination with other treatment techniques for various musculoskeletal and neuromuscular problems. However, no research has evaluated the effect of KT in patients with low back pain (LBP). The purpose of this case was to describe the application of posterior pelvic tilt taping (PPTT) with Kinesio tape as a treatment for chronic LBP and to reduce the anterior pelvic tilt angle. Case report. The patien was a 20-year-old female amateur swimmer with a Cobb's angle (L1-S1) of 68°, a sacral horizontal angle of 45°, and pain in both medial buttock areas and sacroiliac joints. We performed PPTT with Kinesio tape for 2 weeks (six times per week for an average of 9 h each time). The patient’s radiographs showed that the Cobb's angle (L1-S1) had decreased from 68° to 47° and that the sacral horizontal angle had decreased from 45° to 31°. Reductions in hypomobility or motion asymmetry, as assessed by the motion palpation test, and in pain, as measured by the pain-provocation tests, were observed. On palpation for both medial buttock areas in the prone position, the patient felt no pain. The patient experienced no pain or stiffness in the low back area while performing forward flexion in the standing position with knees fully extended when washing dishes in the sink. The case study demonstrated that PPTT intervention favourably affected the pelvic inclination and sacral horizontal angle, leading to beneficial effects on sacroiliac joint dysfunction (SIJD) and medial buttock pain. Additional research on the clinical effects of this taping procedure requires greater numbers of athletes with SIJD or LBP who have inappropriate anterior pelvic tilt angles and hyperlordosis.

  15. Overlapping sphincteroplasty and posterior repair.

    PubMed

    Crane, Andrea K; Myers, Erinn M; Lippmann, Quinn K; Matthews, Catherine A

    2014-12-01

    Knowledge of how to anatomically reconstruct extensive posterior-compartment defects is variable among gynecologists. The objective of this video is to demonstrate an effective technique of overlapping sphincteroplasty and posterior repair. In this video, a scripted storyboard was constructed that outlines the key surgical steps of a comprehensive posterior compartment repair: (1) surgical incision that permits access to posterior compartment and perineal body, (2) dissection of the rectovaginal space up to the level of the cervix, (3) plication of the rectovaginal muscularis, (4) repair of internal and external anal sphincters, and (5) reconstruction of the perineal body. Using a combination of graphic illustrations and live video footage, tips on repair are highlighted. The goals at the end of repair are to: (1) have improved vaginal caliber, (2) increase rectal tone along the entire posterior vaginal wall, (3) have the posterior vaginal wall at a perpendicular plane to the perineal body, (4) reform the hymenal ring, and (5) not have an overly elongated perineal body. This video provides a step-by-step guide on how to perform an overlapping sphincteroplasty and posterior repair.

  16. Medial extrusion of the posterior segment of medial meniscus is a sensitive sign for posterior horn tears.

    PubMed

    Ohishi, Tsuyoshi; Suzuki, Daisuke; Yamamoto, Kazufumi; Banno, Tomohiro; Shimizu, Yuta; Matsuyama, Yukihiro

    2014-01-01

    To evaluate medial extrusion of the posterior segment of the medial meniscus in posterior horn tears. This study enrolled 72 patients without medial meniscal tears (group N), 72 patients with medial meniscal tears without posterior horn tears (group PH-), 44 patients with posterior horn tears of the medial meniscus (group PH+). All meniscal tears were confirmed by arthroscopy. Medial extrusion of the middle segment and the posterior segment was measured on coronal MRIs. Extrusions of both middle and posterior segments in groups PH- and PH+ (middle segment; 2.94±1.51 mm for group PH- and 3.75±1.69 mm for group PH+, posterior segment; 1.85±1.82 mm for group PH- and 4.59±2.74 mm for group PH+) were significantly larger than those in group N (middle segment; 2.04±1.20, posterior segment; 1.21±1.86). Both indicators of extrusion in group PH+ were larger than those in group PH-. In the early OA category, neither middle nor posterior segment in group PH- extruded more than in group N. However, only the posterior segment in group PH+ extruded significantly more than in group N. Multiple lineal regression analyses revealed that posterior segment extrusion was strongly correlated with the posterior horn tears (p<0.001) among groups PH- and PH+. The newly presented indicator for extrusion of the posterior segment of the medial meniscus is associated with posterior horn tears in comparison with the extrusion of the middle segment, especially in the early stages of osteoarthritis. Level II--Diagnostic Study. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. The sacroiliac joint: anatomy, physiology and clinical significance.

    PubMed

    Forst, Stacy L; Wheeler, Michael T; Fortin, Joseph D; Vilensky, Joel A

    2006-01-01

    The sacroiliac joint (SIJ) is a putative source of low back pain. The objective of this article is to provide clinicians with a concise review of SIJ structure and function, diagnostic indicators of SIJ-mediated pain, and therapeutic considerations. The SIJ is a true diarthrodial joint with unique characteristics not typically found in other diarthrodial joints. The joint differs with others in that it has fibrocartilage in addition to hyaline cartilage, there is discontinuity of the posterior capsule, and articular surfaces have many ridges and depressions. The sacroiliac joint is well innervated. Histological analysis of the sacroiliac joint has verified the presence of nerve fibers within the joint capsule and adjoining ligaments. It has been variously described that the sacroiliac joint receives its innervation from the ventral rami of L4 and L5, the superior gluteal nerve, and the dorsal rami of L5, S1, and S2, or that it is almost exclusively derived from the sacral dorsal rami. Even though the sacroiliac joint is a known putative source of low back and lower extremity pain, there are few findings that are pathognomonic of sacroiliac joint pain. The controlled diagnostic blocks utilizing the International Association for the Study of Pain (IASP) criteria demonstrated the prevalence of pain of sacroiliac joint origin in 19% to 30% of the patients suspected to have sacroiliac joint pain. Conservative management includes manual medicine techniques, pelvic stabilization exercises to allow dynamic postural control, and muscle balancing of the trunk and lower extremities. Interventional treatments include sacroiliac joint, intra-articular joint injections, radiofrequency neurotomy, prolotherapy, cryotherapy, and surgical treatment. The evidence for intra-articular injections and radiofrequency neurotomy has been shown to be limited in managing sacroiliac joint pain.

  18. Posterior horn instability of the medial meniscus a sign of posterior meniscotibial ligament insufficiency.

    PubMed

    Mariani, P P

    2011-07-01

    In longstanding chronic anterior cruciate ligament (ACL) insufficiency, we identified an abnormal movement of the posterior medial meniscal horn, likely due to insufficiency of the posteromedial meniscotibial ligament. Passing from extension to flexion or vice versa, the medial posterior horn slides below the posterior rim of the tibia exposing the tibial plateau. Fixation with suture anchors of the meniscotibial ligament through a posteromedial portal restored normal meniscotibial tension and reduced instability of the meniscal posterior horn. The purpose of the present study was to present the arthroscopic features of posterior medial meniscus instability and to report results following arthroscopic repair. During the two-year study period, from 2007 through 2008, this arthroscopic feature was detected in 12 patients, 5 patients had failure of a previous ACL reconstruction and 7 patients had delay in ligamentous reconstruction for various reasons. All patients were affected by severe anterior-posterior translation with 11.3 ± 4.3 mm of side-to-side difference at KT-2000 and by associated rotatory laxity with grade 3 of pivot shift. At follow-up of 1 year, the combined ACL reconstruction and fixation of the posteromedial horn showed a reduction in the rotatory and anteroposterior laxity. This study suggests the importance of a proper arthroscopic evaluation of the posterior medial capsule in patients with chronic ACL insufficiency and highlights the potential presence of an unstable posterior horn of the medial meniscus as an indirect arthroscopic sign of peripheral laxity.

  19. How weak values emerge in joint measurements on cloned quantum systems.

    PubMed

    Hofmann, Holger F

    2012-07-13

    A statistical analysis of optimal universal cloning shows that it is possible to identify an ideal (but nonpositive) copying process that faithfully maps all properties of the original Hilbert space onto two separate quantum systems, resulting in perfect correlations for all observables. The joint probabilities for noncommuting measurements on separate clones then correspond to the real parts of the complex joint probabilities observed in weak measurements on a single system, where the measurements on the two clones replace the corresponding sequence of weak measurement and postselection. The imaginary parts of weak measurement statics can be obtained by replacing the cloning process with a partial swap operation. A controlled-swap operation combines both processes, making the complete weak measurement statistics accessible as a well-defined contribution to the joint probabilities of fully resolved projective measurements on the two output systems.

  20. Feasibility of ultrasound-guided sacroiliac joint injection considering sonoanatomic landmarks at two different levels in cadavers and patients.

    PubMed

    Klauser, Andrea; De Zordo, Tobias; Feuchtner, Gudrun; Sögner, Peter; Schirmer, Michael; Gruber, Johann; Sepp, Norbert; Moriggl, Bernhard

    2008-11-15

    Sacroiliitis is often caused by rheumatic diseases, and besides other therapeutic options, treatment consists of intraarticular injection of corticosteroids. The purpose of this study was to assess the feasibility of ultrasound (US)-guided sacroiliac joint (SI joint) injection at 2 different puncture levels in cadavers and patients when defined sonoanatomic landmarks were considered. After defining sonoanatomic landmarks, US-guided needle insertion was performed in 10 human cadavers (20 SI joints) at 2 different puncture sites. Upper level was defined at the level of the posterior sacral foramen 1 and lower level at the level of the posterior sacral foramen 2. In 10 patients with unilateral sacroiliitis, injection at the most feasible level was attempted. Computed tomography confirmed correct intraarticular needle placement in cadavers by showing the tip of the needle in the joint and intraarticular diffusion of contrast media in 16 (80%) of 20 SI joints (upper level 7 [70%] of 10; lower level 9 [90%] of 10). In all 4 cases in which needle insertion failed, intraarticular SI joint injection at the other level was successful. In patients, 100% of US-guided injections were successful (8 lower level, 2 upper level), with a mean pain relief of 8.6 after 3 months. US guidance of needle insertion into SI joints was feasible at both levels when defined sonoanatomic landmarks were used. If SI joint alterations do not allow for direct visualization of the dorsal joint space of the lower level, which is easier to access, the upper level might offer an appropriate alternative.

  1. Late-onset Alzheimer disease genetic variants in posterior cortical atrophy and posterior AD.

    PubMed

    Carrasquillo, Minerva M; Khan, Qurat ul Ain; Murray, Melissa E; Krishnan, Siddharth; Aakre, Jeremiah; Pankratz, V Shane; Nguyen, Thuy; Ma, Li; Bisceglio, Gina; Petersen, Ronald C; Younkin, Steven G; Dickson, Dennis W; Boeve, Bradley F; Graff-Radford, Neill R; Ertekin-Taner, Nilüfer

    2014-04-22

    To investigate association of genetic risk factors for late-onset Alzheimer disease (LOAD) with risk of posterior cortical atrophy (PCA), a syndrome of visual impairment with predominant Alzheimer disease (AD) pathology in posterior cortical regions, and with risk of "posterior AD" neuropathology. We assessed 81 participants with PCA diagnosed clinically and 54 with neuropathologic diagnosis of posterior AD vs 2,523 controls for association with 11 significant single nucleotide polymorphisms (SNPs) from published LOAD risk genome-wide association studies. There was highly significant association with APOE ε4 and increased risk of PCA (p = 0.0003, odds ratio [OR] = 3.17) and posterior AD (p = 1.11 × 10(-17), OR = 6.43). No other locus was significant after corrections for multiple testing, although rs11136000 near CLU (p = 0.019, OR = 0.60) and rs744373 near BIN1 (p = 0.025, OR = 1. 63) associated nominally significantly with posterior AD, and rs3851179 at the PICALM locus had significant association with PCA (p = 0.0003, OR = 2.84). ABCA7 locus SNP rs3764650, which was also tested under the recessive model because of Hardy-Weinberg disequilibrium, also had nominally significant association with PCA risk. The direction of association at APOE, CLU, and BIN1 loci was the same for participants with PCA and posterior AD. The effects for all SNPs, except rs3851179, were consistent with those for LOAD risk. We identified a significant effect for APOE and nominate CLU, BIN1, and ABCA7 as additional risk loci for PCA and posterior AD. Our findings suggest that at least some of the genetic risk factors for LOAD are shared with these atypical conditions and provide effect-size estimates for their future genetic studies.

  2. Computer simulation of random variables and vectors with arbitrary probability distribution laws

    NASA Technical Reports Server (NTRS)

    Bogdan, V. M.

    1981-01-01

    Assume that there is given an arbitrary n-dimensional probability distribution F. A recursive construction is found for a sequence of functions x sub 1 = f sub 1 (U sub 1, ..., U sub n), ..., x sub n = f sub n (U sub 1, ..., U sub n) such that if U sub 1, ..., U sub n are independent random variables having uniform distribution over the open interval (0,1), then the joint distribution of the variables x sub 1, ..., x sub n coincides with the distribution F. Since uniform independent random variables can be well simulated by means of a computer, this result allows one to simulate arbitrary n-random variables if their joint probability distribution is known.

  3. Posterior stability in fixed-bearing versus mobile-bearing total knee replacement: a radiological comparison of two implants.

    PubMed

    Siebold, R; Louisia, S; Canty, J; Bartlett, R J

    2007-02-01

    Posterior tibial translation in total knee replacement (TKR) could be one major factor for PE wear, delamination and loosening of the tibial component due to increased shear forces and component-to-bone interface stress. The aim of this study was to assess the posterior stability of two different designs of posterior cruciate ligament (PCL) substituting TKR. In this non-randomised consecutive study 43 patients underwent TKR for primary osteoarthritis. Twenty-six patients in group FB received a deep-dished fixed-bearing Duracon TKR (Howmedica, Rutherford, NJ, USA) and 17 patients in group MB a deep-dished rotating mobile-bearing Duracon TKR. In both groups the PCL was resected. All patients had pre- and postoperative kneeling stress radiographs and were clinically evaluated with the Knee Society Score. Posterior tibial translation was measured by tracing a line along the posterior tibial cortex in relationship to the posterior edge of Blumensaat's line. The average follow-up was 13 months for group FB and 11 months for group MB. Both groups demonstrated a statistical significant increase of the mean posterior tibial translation on kneeling stress X-ray of 4.1 mm (group FB) (P < 0.001) and of 6.6 mm (group MB) (P < 0.001) compared to pre-operative. Group MB showed a significant higher posterior draw (P < 0.008). Clinical assessment using the Knee Society Score showed comparable short-term results. The deep-dished fixed-bearing TKR as well as the deep-dished rotating mobile-bearing TKR demonstrated significant posterior tibial translation on kneeling stress X-ray. It remains to be determined what amount of joint play is optimal for clinical function and to minimise shear forces and PE wear. Moreover the amount of posterior tibial translation was significantly higher with the mobile-bearing insert, which could be directly related to the asymmetric rotational mobility of the tibial insert. A long-term follow-up is necessary to investigate whether our findings correlate

  4. The effect of complete radial lateral meniscus posterior root tear on the knee contact mechanics: a finite element analysis.

    PubMed

    Bao, H R C; Zhu, D; Gong, H; Gu, G S

    2013-03-01

    meniscus continues to provide some load transmission and distribution functions across the joint. The posterior meniscofemoral ligament prevents excessive radial displacement of the posterior root torn lateral meniscus and assists the torn lateral meniscus in transmitting a certain amount of stress in the lateral compartment.

  5. Posterior, Lateral, and Anterior Hip Pain Due to Musculoskeletal Origin: A Narrative Literature Review of History, Physical Examination, and Diagnostic Imaging.

    PubMed

    Battaglia, Patrick J; D'Angelo, Kevin; Kettner, Norman W

    2016-12-01

    The purpose of this study was to present a narrative review of the literature of musculoskeletal causes of adult hip pain, with special attention to history, physical examination, and diagnostic imaging. A narrative review of the English medical literature was performed by using the search terms "hip pain" AND "anterior," "lateral," and "posterior." Additionally, specific entities of hip pain or pain referral sources to the hip were searched for. We used the PubMed search engine through January 15, 2016. Musculoskeletal sources of adult hip pain can be divided into posterior, lateral, and anterior categories. For posterior hip pain, select considerations include lumbar spine and femoroacetabular joint referral, sacroiliac joint pathology, piriformis syndrome, and proximal hamstring tendinopathy. Gluteal tendinopathy and iliotibial band thickening are the most common causes of lateral hip pain. Anterior hip pain is further divided into causes that are intra-articular (ie, labral tear, osteoarthritis, osteonecrosis) and extra-articular (ie, snapping hip and inguinal disruption [athletic pubalgia]). Entrapment neuropathies and myofascial pain should also be considered in each compartment. A limited number of historical features and physical examination tests for evaluation of adult hip pain are supported by the literature and are discussed in this article. Depending on the clinical differential, the gamut of diagnostic imaging modalities recommended for accurate diagnosis include plain film radiography, computed tomography, magnetic resonance imaging, skeletal scintigraphy, and ultrasonography. The evaluation of adult hip pain is challenging. Clinicians should consider posterior, lateral, and anterior sources of pain while keeping in mind that these may overlap.

  6. Anterior fracture dislocation of the sacroiliac joint: A case report and literature review.

    PubMed

    Xiao, Jianlin; Wang, Yang; Zhang, Minglei; Jiang, Rui; Zhu, Tongtong; Liu, Guangyao; Zuo, Jianlin

    2017-08-09

    Publications describing the diagnosis and treatment of anterior dislocation of the sacroiliac joint are scarce. We report the case a 19-year-old female at 8 weeks' gestation who presented with anterior fracture dislocation of the right sacroiliac joint, posterior fracture dislocation of the left sacroiliac joint (crescent fracture), and incomplete abortion resulting from high energy trauma. Orthopedic surgery involved standard anterior sacroiliac joint plating using an ilioinguinal approach combined with a modified Stoppa approach. Three attempts at complete abortion failed. Complete abortion was eventually achieved by dilatation and curettage two weeks after orthopedic surgery. Our findings reveal a need to improve techniques for diagnosis and treatment of anterior fracture dislocation of the sacroiliac joint, so greater attention can be paid to the rapid and effective management of associated comorbidities, and those resulting from the initial trauma.

  7. Probability distributions for multimeric systems.

    PubMed

    Albert, Jaroslav; Rooman, Marianne

    2016-01-01

    We propose a fast and accurate method of obtaining the equilibrium mono-modal joint probability distributions for multimeric systems. The method necessitates only two assumptions: the copy number of all species of molecule may be treated as continuous; and, the probability density functions (pdf) are well-approximated by multivariate skew normal distributions (MSND). Starting from the master equation, we convert the problem into a set of equations for the statistical moments which are then expressed in terms of the parameters intrinsic to the MSND. Using an optimization package on Mathematica, we minimize a Euclidian distance function comprising of a sum of the squared difference between the left and the right hand sides of these equations. Comparison of results obtained via our method with those rendered by the Gillespie algorithm demonstrates our method to be highly accurate as well as efficient.

  8. Posterior capsule opacification.

    PubMed

    Wormstone, I Michael; Wang, Lixin; Liu, Christopher S C

    2009-02-01

    Posterior Capsule Opacification (PCO) is the most common complication of cataract surgery. At present the only means of treating cataract is by surgical intervention, and this initially restores high visual quality. Unfortunately, PCO develops in a significant proportion of patients to such an extent that a secondary loss of vision occurs. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens. The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. However, on the remaining anterior capsule, lens epithelial cells stubbornly reside despite enduring the rigours of surgical trauma. This resilient group of cells then begin to re-colonise the denuded regions of the anterior capsule, encroach onto the intraocular lens surface, occupy regions of the outer anterior capsule and most importantly of all begin to colonise the previously cell-free posterior capsule. Cells continue to divide, begin to cover the posterior capsule and can ultimately encroach on the visual axis resulting in changes to the matrix and cell organization that can give rise to light scatter. This review will describe the biological mechanisms driving PCO progression and discuss the influence of IOL design, surgical techniques and putative drug therapies in regulating the rate and severity of PCO.

  9. Little Bayesians or Little Einsteins? Probability and Explanatory Virtue in Children's Inferences

    ERIC Educational Resources Information Center

    Johnston, Angie M.; Johnson, Samuel G. B.; Koven, Marissa L.; Keil, Frank C.

    2017-01-01

    Like scientists, children seek ways to explain causal systems in the world. But are children scientists in the strict Bayesian tradition of maximizing posterior probability? Or do they attend to other explanatory considerations, as laypeople and scientists--such as Einstein--do? Four experiments support the latter possibility. In particular, we…

  10. Kinematic analysis of postural reactions to a posterior translation in rocker bottom shoes in younger and older adults.

    PubMed

    Kimel-Scott, Dorothy R; Gulledge, Elisha N; Bolena, Ryan E; Albright, Bruce C

    2014-01-01

    Shoes with rocker bottom soles are utilized by persons with diabetic peripheral neuropathy to reduce plantar pressures during gait. The risk of falls increases with age and is compounded by diabetic neuropathy. The purpose of this study was to analyze how rocker bottom shoes affect posture control of older adults (50-75 years old) and younger adults (20-35 years old) in response to posterior slide perturbations. The postural response to a posterior platform translation was normalized among subjects by applying the below threshold stepping velocity (BTSV) for each subject. The BTSV was the fastest velocity of platform translation that did not cause a stepping response while wearing the rocker bottom shoes. Joint excursion, time to first response, response time, and variability of mean peak joint angles were analyzed at the ankle, knee, hip, trunk, and head in the sagittal plane. The statistical analysis was a 2-factor mixed repeated measures design to determine interactions between and within shoe types and age groups. While wearing rocker bottom shoes, both age groups exhibited increased joint excursion, differences in time to initial response, and longer response time. The older group demonstrated decreased joint excursion and increased time to initial response compared to the younger group, as well as a significantly slower mean BTSV. These findings support the conclusion that in healthy older adults and in populations at risk for falls, the use of rocker bottom or other unstable shoes may increase the potential of falls when confronted with a standing perturbation such as a forceful slip or trip. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Fast Bayesian approach for modal identification using free vibration data, Part I - Most probable value

    NASA Astrophysics Data System (ADS)

    Zhang, Feng-Liang; Ni, Yan-Chun; Au, Siu-Kui; Lam, Heung-Fai

    2016-03-01

    The identification of modal properties from field testing of civil engineering structures is becoming economically viable, thanks to the advent of modern sensor and data acquisition technology. Its demand is driven by innovative structural designs and increased performance requirements of dynamic-prone structures that call for a close cross-checking or monitoring of their dynamic properties and responses. Existing instrumentation capabilities and modal identification techniques allow structures to be tested under free vibration, forced vibration (known input) or ambient vibration (unknown broadband loading). These tests can be considered complementary rather than competing as they are based on different modeling assumptions in the identification model and have different implications on costs and benefits. Uncertainty arises naturally in the dynamic testing of structures due to measurement noise, sensor alignment error, modeling error, etc. This is especially relevant in field vibration tests because the test condition in the field environment can hardly be controlled. In this work, a Bayesian statistical approach is developed for modal identification using the free vibration response of structures. A frequency domain formulation is proposed that makes statistical inference based on the Fast Fourier Transform (FFT) of the data in a selected frequency band. This significantly simplifies the identification model because only the modes dominating the frequency band need to be included. It also legitimately ignores the information in the excluded frequency bands that are either irrelevant or difficult to model, thereby significantly reducing modeling error risk. The posterior probability density function (PDF) of the modal parameters is derived rigorously from modeling assumptions and Bayesian probability logic. Computational difficulties associated with calculating the posterior statistics, including the most probable value (MPV) and the posterior covariance matrix

  12. Functional anatomy of the temporo-mandibular joint (II).

    PubMed

    Sava, Anca; Scutariu, Monica

    2012-01-01

    Jaw movement is analyzed as an action between two rigid components jointed together in a particular way, the movable mandible against the stabilized cranium. Opening and closing movements are symmetrical; that is, both sides of the cranio-mandibular articulation are making the same movements. Protrusive and retrusive movements may also be symmetrical. The mandibular muscles determine all the complicated postures and-movements of the jaw. Their behavior can be greatly clarified by restating certain fundamentals crucial to purposive muscular activity. The joint derives its arterial supply from the superficial temporal artery and the maxillary artery. Branches of the auriculo-temporal and masseteric nerves and postganglionic sympathetic nerves supply the tissues associated with the capsular ligament and the looser posterior bilaminar extension of the disc.

  13. Seabed roughness parameters from joint backscatter and reflection inversion at the Malta Plateau.

    PubMed

    Steininger, Gavin; Holland, Charles W; Dosso, Stan E; Dettmer, Jan

    2013-09-01

    This paper presents estimates of seabed roughness and geoacoustic parameters and uncertainties on the Malta Plateau, Mediterranean Sea, by joint Bayesian inversion of mono-static backscatter and spherical wave reflection-coefficient data. The data are modeled using homogeneous fluid sediment layers overlying an elastic basement. The scattering model assumes a randomly rough water-sediment interface with a von Karman roughness power spectrum. Scattering and reflection data are inverted simultaneously using a population of interacting Markov chains to sample roughness and geoacoustic parameters as well as residual error parameters. Trans-dimensional sampling is applied to treat the number of sediment layers and the order (zeroth or first) of an autoregressive error model (to represent potential residual correlation) as unknowns. Results are considered in terms of marginal posterior probability profiles and distributions, which quantify the effective data information content to resolve scattering/geoacoustic structure. Results indicate well-defined scattering (roughness) parameters in good agreement with existing measurements, and a multi-layer sediment profile over a high-speed (elastic) basement, consistent with independent knowledge of sand layers over limestone.

  14. Exploring the IMF of star clusters: a joint SLUG and LEGUS effort

    NASA Astrophysics Data System (ADS)

    Ashworth, G.; Fumagalli, M.; Krumholz, M. R.; Adamo, A.; Calzetti, D.; Chandar, R.; Cignoni, M.; Dale, D.; Elmegreen, B. G.; Gallagher, J. S., III; Gouliermis, D. A.; Grasha, K.; Grebel, E. K.; Johnson, K. E.; Lee, J.; Tosi, M.; Wofford, A.

    2017-08-01

    We present the implementation of a Bayesian formalism within the Stochastically Lighting Up Galaxies (slug) stellar population synthesis code, which is designed to investigate variations in the initial mass function (IMF) of star clusters. By comparing observed cluster photometry to large libraries of clusters simulated with a continuously varying IMF, our formalism yields the posterior probability distribution function (PDF) of the cluster mass, age and extinction, jointly with the parameters describing the IMF. We apply this formalism to a sample of star clusters from the nearby galaxy NGC 628, for which broad-band photometry in five filters is available as part of the Legacy ExtraGalactic UV Survey (LEGUS). After allowing the upper-end slope of the IMF (α3) to vary, we recover PDFs for the mass, age and extinction that are broadly consistent with what is found when assuming an invariant Kroupa IMF. However, the posterior PDF for α3 is very broad due to a strong degeneracy with the cluster mass, and it is found to be sensitive to the choice of priors, particularly on the cluster mass. We find only a modest improvement in the constraining power of α3 when adding Hα photometry from the companion Hα-LEGUS survey. Conversely, Hα photometry significantly improves the age determination, reducing the frequency of multi-modal PDFs. With the aid of mock clusters, we quantify the degeneracy between physical parameters, showing how constraints on the cluster mass that are independent of photometry can be used to pin down the IMF properties of star clusters.

  15. Posterior to Anteriorly Directed Screws for Management of Talar Neck Fractures.

    PubMed

    Beltran, Michael J; Mitchell, Phillip M; Collinge, Cory A

    2016-10-01

    Screws placed from posterior to anterior have been shown to be biomechanically and anatomically superior in the fixation of talar neck and neck-body fractures, yet most surgeons continue to place screws from an anterior start point. The safety and efficacy of percutaneously applied posterior screws has not been clinically defined, and functional outcomes after their use is lacking. After institutional review board approval, we performed a retrospective review of 24 consecutive talar neck fractures treated by a single surgeon that utilized posterior-to-anterior screw fixation. Clinical, radiographic, and functional outcomes were assessed at a minimum follow-up of 12 months. Functional outcomes including the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, Olerud-Molander Scores, and the Short Form 36 (SF-36) measurement were collected and reviewed. Average patient follow-up was 44 months. According to the classification system of Canale and Kelly, there were 4 type I fractures, 15 type II fractures, 4 type III fractures, and 1 type IV fracture. Four patients had open fractures. One superficial wound infection occurred, 1 patient reported FHL stiffness, and 6 complained of numbness or paresthesias in the distribution of the sural nerve (5 transient, 1 permanent). One reoperation was required to exchange a screw impinging on the talonavicular joint. Radiographically, 44% developed a positive Hawkins sign, and the specificity of this finding was 100% for talar dome viability. Avascular necrosis developed in 43% of patients, with 33% revascularizing and none going on to collapse. Subtalar arthrosis developed in 62% of patients. Screws placed from posterior to anterior are a useful technique in the treatment of talar neck fractures. Functional outcomes following their use appear favorable compared with recent reports with minimal risk to local structures. Level IV, retrospective case series. © The Author(s) 2016.

  16. The anterior borders of the clavicle and the acromion are not always aligned in the intact acromioclavicular joint: a cadaveric study.

    PubMed

    Barth, Johannes; Boutsiadis, Achilleas; Narbona, Pablo; Lädermann, Alexandre; Arrigoni, Paolo; Adams, Christopher R; Burkhart, Stephen S; Denard, Patrick J

    2017-07-01

    The aim of this study was to find reliable anatomic landmarks of the normal acromioclavicular joint (ACJ) that could enable the precise evaluation of the horizontal displacement of the clavicle after dislocation. The hypothesis was that the anterior borders of the acromion and the clavicle are always aligned in intact ACJs. In 30 cadaveric specimens, the anterior and posterior borders of the ACJ's articular facets and the most prominent anterior and posterior bony landmarks of the acromion and the clavicle were identified. The anterior and posterior overhang of the acromion and the clavicle was measured in relation to the borders of the articular facets. Therefore, the possible anterior and posterior alignment of the ACJ was evaluated. Anteriorly, only 18 ACJs (60%) were aligned whereas 7 (24%) had major overhang of the acromion and 3 (10%) had major overhang of the clavicle. Similarly, 18 cases (60%) were posteriorly aligned, whereas 6 (20%) had major clavicular overhang and 4 (14%) had major overhang of the acromion. In 78% of these cases, the ACJ was aligned as well anteriorly as posteriorly (P < .001). Finally, the larger the width of the acromion (P = .032) or the clavicle (P = .049), the better the posterior joint alignment. Our hypothesis was not verified. The acromion and clavicle are not perfectly aligned in a significant number of specimens with intact ACJs (40% of cases). The most reliable landmarks remain their articular facets. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  17. Periprosthetic Joint Infections: Clinical and Bench Research

    PubMed Central

    Legout, Laurence; Senneville, Eric

    2013-01-01

    Prosthetic joint infection is a devastating complication with high morbidity and substantial cost. The incidence is low but probably underestimated. Despite a significant basic and clinical research in this field, many questions concerning the definition of prosthetic infection as well the diagnosis and the management of these infections remained unanswered. We review the current literature about the new diagnostic methods, the management and the prevention of prosthetic joint infections. PMID:24288493

  18. Muscular activation during plyometric exercises in 90° of glenohumeral joint abduction.

    PubMed

    Ellenbecker, Todd S; Sueyoshi, Tetsuro; Bailie, David S

    2015-01-01

    Plyometric exercises are frequently used to increase posterior rotator cuff and periscapular muscle strength and simulate demands and positional stresses in overhead athletes. The purpose of this study was to provide descriptive data on posterior rotator cuff and scapular muscle activation during upper extremity plyometric exercises in 90° of glenohumeral joint abduction. Levels of muscular activity in the posterior rotator cuff and scapular stabilizers will be high during plyometric shoulder exercises similar to previously reported electromyographic (EMG) levels of shoulder rehabilitation exercises. Descriptive laboratory study. Twenty healthy subjects were tested using surface EMG during the performance of 2 plyometric shoulder exercises: prone external rotation (PERP) and reverse catch external rotation (RCP) using a handheld medicine ball. Electrode application included the upper and lower trapezius (UT and LT, respectively), serratus anterior (SA), infraspinatus (IN), and the middle and posterior deltoid (MD and PD, respectively) muscles. A 10-second interval of repetitive plyometric exercise (PERP) and 3 repetitions of RCP were sampled. Peak and average normalized EMG data were generated. Normalized peak and average IN activity ranged between 73% and 102% and between 28% and 52% during the plyometric exercises, respectively, with peak and average LT activity measured between 79% and 131% and between 31% and 61%. SA activity ranged between 76% and 86% for peak and between 35% and 37% for average activity. Muscular activity levels in the MD and PD ranged between 49% and 72% and between 12% and 33% for peak and average, respectively. Moderate to high levels of muscular activity were measured in the rotator cuff and scapular stabilizers during these plyometric exercises with the glenohumeral joint abducted 90°.

  19. Quasi-probabilities in conditioned quantum measurement and a geometric/statistical interpretation of Aharonov's weak value

    NASA Astrophysics Data System (ADS)

    Lee, Jaeha; Tsutsui, Izumi

    2017-05-01

    We show that the joint behavior of an arbitrary pair of (generally noncommuting) quantum observables can be described by quasi-probabilities, which are an extended version of the standard probabilities used for describing the outcome of measurement for a single observable. The physical situations that require these quasi-probabilities arise when one considers quantum measurement of an observable conditioned by some other variable, with the notable example being the weak measurement employed to obtain Aharonov's weak value. Specifically, we present a general prescription for the construction of quasi-joint probability (QJP) distributions associated with a given combination of observables. These QJP distributions are introduced in two complementary approaches: one from a bottom-up, strictly operational construction realized by examining the mathematical framework of the conditioned measurement scheme, and the other from a top-down viewpoint realized by applying the results of the spectral theorem for normal operators and their Fourier transforms. It is then revealed that, for a pair of simultaneously measurable observables, the QJP distribution reduces to the unique standard joint probability distribution of the pair, whereas for a noncommuting pair there exists an inherent indefiniteness in the choice of such QJP distributions, admitting a multitude of candidates that may equally be used for describing the joint behavior of the pair. In the course of our argument, we find that the QJP distributions furnish the space of operators in the underlying Hilbert space with their characteristic geometric structures such that the orthogonal projections and inner products of observables can be given statistical interpretations as, respectively, “conditionings” and “correlations”. The weak value Aw for an observable A is then given a geometric/statistical interpretation as either the orthogonal projection of A onto the subspace generated by another observable B, or

  20. Self-referenced processing, neurodevelopment and joint attention in autism.

    PubMed

    Mundy, Peter; Gwaltney, Mary; Henderson, Heather

    2010-09-01

    This article describes a parallel and distributed processing model (PDPM) of joint attention, self-referenced processing and autism. According to this model, autism involves early impairments in the capacity for rapid, integrated processing of self-referenced (proprioceptive and interoceptive) and other-referenced (exteroceptive) information. Measures of joint attention have proven useful in research on autism because they are sensitive to the early development of the 'parallel' and integrated processing of self- and other-referenced stimuli. Moreover, joint attention behaviors are a consequence, but also an organizer of the functional development of a distal distributed cortical system involving anterior networks including the prefrontal and insula cortices, as well as posterior neural networks including the temporal and parietal cortices. Measures of joint attention provide early behavioral indicators of atypical development in this parallel and distributed processing system in autism. In addition it is proposed that an early, chronic disturbance in the capacity for integrating self- and other-referenced information may have cascading effects on the development of self awareness in autism. The assumptions, empirical support and future research implications of this model are discussed.

  1. A biomechanical analysis of upper extremity kinetics in children with cerebral palsy using anterior and posterior walkers.

    PubMed

    Konop, Katherine A; Strifling, Kelly M B; Wang, Mei; Cao, Kevin; Schwab, Jeffrey P; Eastwood, Daniel; Jackson, Scott; Ackman, Jeffrey D; Harris, Gerald F

    2009-10-01

    Upper extremity (UE) joint kinetics during aided ambulation is an area of research that is not well characterized in the current literature. Biped UE joints are not anatomically designed to be weight bearing, therefore it is important to quantify UE kinetics during assisted gait. This will help to better understand the biomechanical implications of UE weight bearing, and enable physicians to prescribe more effective methods for treatment and therapy, perhaps minimizing excessive loads and torques. To address this challenge, an UE model that incorporates both kinematics and kinetics has been developed for use with walkers instrumented with load cells. In this study, the UE joint kinetics are calculated for 10 children with cerebral palsy using both anterior and posterior walkers. Three-dimensional joint reaction forces and moments are fully characterized for the wrist, elbow, and shoulder (glenohumeral) joints for both walker types. Statistical analysis methods are used to quantify the differences in forces or moments between the two walker types. Comparisons showed no significant differences in kinetic joint parameters between walker types. Results from a power analysis of the current data are provided which may be useful for planning longer term clinical studies. If risk factors for UE joint pathology can be identified early, perhaps a change in gait training routine, walker prescription, or walker design could prevent further harm.

  2. Dynamic Uncertain Causality Graph for Knowledge Representation and Probabilistic Reasoning: Directed Cyclic Graph and Joint Probability Distribution.

    PubMed

    Zhang, Qin

    2015-07-01

    Probabilistic graphical models (PGMs) such as Bayesian network (BN) have been widely applied in uncertain causality representation and probabilistic reasoning. Dynamic uncertain causality graph (DUCG) is a newly presented model of PGMs, which can be applied to fault diagnosis of large and complex industrial systems, disease diagnosis, and so on. The basic methodology of DUCG has been previously presented, in which only the directed acyclic graph (DAG) was addressed. However, the mathematical meaning of DUCG was not discussed. In this paper, the DUCG with directed cyclic graphs (DCGs) is addressed. In contrast, BN does not allow DCGs, as otherwise the conditional independence will not be satisfied. The inference algorithm for the DUCG with DCGs is presented, which not only extends the capabilities of DUCG from DAGs to DCGs but also enables users to decompose a large and complex DUCG into a set of small, simple sub-DUCGs, so that a large and complex knowledge base can be easily constructed, understood, and maintained. The basic mathematical definition of a complete DUCG with or without DCGs is proved to be a joint probability distribution (JPD) over a set of random variables. The incomplete DUCG as a part of a complete DUCG may represent a part of JPD. Examples are provided to illustrate the methodology.

  3. Comparison of upper extremity kinematics in children with spastic diplegic cerebral palsy using anterior and posterior walkers.

    PubMed

    Strifling, Kelly M B; Lu, Na; Wang, Mei; Cao, Kevin; Ackman, Jeffrey D; Klein, John P; Schwab, Jeffrey P; Harris, Gerald F

    2008-10-01

    This prospective study analyzes the upper extremity kinematics of 10 children with spastic diplegic cerebral palsy using anterior and posterior walkers. Although both types of walkers are commonly prescribed by clinicians, no quantitative data comparing the two in regards to upper extremity motion has been published. The study methodology included testing of each subject with both types of walkers in a motion analysis laboratory after an acclimation period of at least 1 month. Overall results showed that statistically, both walkers are relatively similar. With both anterior and posterior walkers, the shoulders were extended, elbows flexed, and wrists extended. Energy expenditure, walking speed and stride length was also similar with both walker types. Several differences were also noted although not statistically significant. Anterior torso tilt was reduced with the posterior walker and shoulder extension and elbow flexion were increased. Outcomes analysis indicated that differences in upper extremity torso and joint motion were not dependent on spasticity or hand dominance. These findings may help to build an understanding of upper extremity motion in walker-assisted gait and potentially to improve walker prescription.

  4. Radiographic cup position following posterior and lateral approach to total hip arthroplasty. An explorative randomized controlled trial.

    PubMed

    Kruse, Christine; Rosenlund, Signe; Broeng, Leif; Overgaard, Søren

    2018-01-01

    The two most common surgical approaches to total hip arthroplasty are the posterior approach and lateral approach. The surgical approach may influence cup positioning and restoration of the offset, which may affect the biomechanical properties of the hip joint. The primary aim was to compare cup position between posterior approach and lateral approach. Secondary aims were to compare femoral offset, abductor moment arm and leg length discrepancy between the two approaches. Eighty patients with primary hip osteoarthritis were included in a randomized controlled trial and assigned to total hip arthroplasty using posterior approach or lateral approach. Postoperative radiographs from 38 patients in each group were included in this study for measurement of cup anteversion and inclination. Femoral offset, cup offset, total offset, abductor moment arm and leg length discrepancy were measured on preoperative and postoperative radiographs in 28 patients in each group. We found that mean anteversion was 5° larger in the posterior approach group (95% CI, -8.1 to -1.4; p = 0.006), while mean inclination was 5° less steep (95% CI, 2.7 to 7.2; p<0.001) compared with the lateral approach group. The posterior approach group had a larger mean femoral offset of 4.3mm (95% CI, -7.4 to -1.3, p = 0.006), mean total offset of 6.3mm (95% CI, -9.6 to -3; p<0.001) and mean abductor moment arm of 4.8mm (95% CI, -7.6 to -1.9; p = 0.001) compared with the lateral approach group. We found a larger cup anteversion but less steep cup inclination in the posterior approach group compared with the lateral approach group. Femoral offset and abductor moment arm were restored after total hip arthroplasty using lateral approach but significantly increased when using posterior approach.

  5. [The Postero-Lateral Approach--An Alternative to Closed Anterior-Posterior Screw Fixation of a Dislocated Postero-Lateral Fragment of the Distal Tibia in Complex Ankle Fractures].

    PubMed

    von Rüden, C; Hackl, S; Woltmann, A; Friederichs, J; Bühren, V; Hierholzer, C

    2015-06-01

    The dislocated posterolateral fragment of the distal tibia is considered as a key fragment for the successful reduction of comminuted ankle fractures. The reduction of this fragment can either be achieved indirectly by joint reduction using the technique of closed anterior-posterior screw fixation, or directly using the open posterolateral approach followed by plate fixation. The aim of this study was to compare the outcome after stabilization of the dislocated posterolateral tibia fragment using either closed reduction and screw fixation, or open reduction and plate fixation via the posterolateral approach in complex ankle fractures. In a prospective study between 01/2010 and 12/2012, all mono-injured patients with closed ankle fractures and dislocated posterolateral tibia fragments were assessed 12 months after osteosynthesis. Parameters included: size of the posterolateral tibia fragment relative to the tibial joint surface (CT scan, in %) as an indicator of injury severity, unreduced area of tibial joint surface postoperatively, treatment outcome assessed by using the "Ankle Fracture Scoring System" (AFSS), as well as epidemiological data and duration of the initial hospital treatment. In 11 patients (10 female, 1 male; age 51.6 ± 2.6 years [mean ± SEM], size of tibia fragment 42.1 ± 2.5 %) the fragment fixation was performed using a posterolateral approach. Impaired postoperative wound healing occurred in 2 patients of this group. In the comparison group, 12 patients were treated using the technique of closed anterior-posterior screw fixation (10 female, 2 male; age 59.5 ± 6.7 years, size of tibia fragment 45.9 ± 1.5 %). One patient of this group suffered an incomplete lesion of the superficial peroneal nerve. Radiological evaluation of the joint surface using CT scan imaging demonstrated significantly less dislocation of the tibial joint surface following the open posterolateral approach (0.60 ± 0.20 mm) compared to the closed

  6. The influence of patellofemoral joint contact geometry on the modeling of three dimensional patellofemoral joint forces.

    PubMed

    Powers, Christopher M; Chen, Yu-Jen; Scher, Irving; Lee, Thay Q

    2006-01-01

    The purpose of this study was to determine the influence of patellofemoral joint contact geometry on the modeling of three-dimensional patellofemoral joint forces. To achieve this goal, patellofemoral joint reaction forces (PFJRFs) that were measured from an in-vitro cadaveric set-up were compared to PFJRFs estimated from a computer model that did not consider patellofemoral joint contact geometry. Ten cadaver knees were used in this study. Each was mounted on a custom jig that was fixed to an Instron frame. Quadriceps muscle loads were accomplished using a pulley system and weights. The force in the patellar ligament was obtained using a buckle transducer. To quantify the magnitude and direction of the PFJRF, a six-axis load cell was incorporated into the femoral fixation system so that a rigid body assumption could be made. PFJRF data were obtained at 0 degrees , 20 degrees , 40 degrees and 60 degrees of knee flexion. Following in vitro testing, SIMM modeling software was used to develop computational models based on the three-dimensional coordinates (Microscribe digitizer) of individual muscle and patellar ligament force vectors obtained from the cadaver knees. The overall magnitude of the PFJRF estimated from the computer generated models closely matched the direct measurements from the in vitro set-up (Pearson's correlation coefficient, R(2)=0.91, p<0.001). Although the computational model accurately estimated the posteriorly directed forces acting on the joint, some discrepancies were noted in the forces acting in the superior and lateral directions. These differences however, were relatively small when expressed as a total of the overall PFJRF magnitude.

  7. Assessing Goodness of Fit in Item Response Theory with Nonparametric Models: A Comparison of Posterior Probabilities and Kernel-Smoothing Approaches

    ERIC Educational Resources Information Center

    Sueiro, Manuel J.; Abad, Francisco J.

    2011-01-01

    The distance between nonparametric and parametric item characteristic curves has been proposed as an index of goodness of fit in item response theory in the form of a root integrated squared error index. This article proposes to use the posterior distribution of the latent trait as the nonparametric model and compares the performance of an index…

  8. In vivo six-degree-of-freedom knee-joint kinematics in overground and treadmill walking following total knee arthroplasty.

    PubMed

    Guan, Shanyuanye; Gray, Hans A; Schache, Anthony G; Feller, Julian; de Steiger, Richard; Pandy, Marcus G

    2017-08-01

    No data are available to describe six-degree-of-freedom (6-DOF) knee-joint kinematics for one complete cycle of overground walking following total knee arthroplasty (TKA). The aims of this study were firstly, to measure 6-DOF knee-joint kinematics and condylar motion for overground walking following TKA; and secondly, to determine whether such data differed between overground and treadmill gait when participants walked at the same speed during both tasks. A unique mobile biplane X-ray imaging system enabled accurate measurement of 6-DOF TKA knee kinematics during overground walking by simultaneously tracking and imaging the joint. The largest rotations occurred for flexion-extension and internal-external rotation whereas the largest translations were associated with joint distraction and anterior-posterior drawer. Strong associations were found between flexion-extension and adduction-abduction (R 2  = 0.92), joint distraction (R 2  = 1.00), and anterior-posterior translation (R 2  = 0.77), providing evidence of kinematic coupling in the TKA knee. Although the measured kinematic profiles for overground walking were grossly similar to those for treadmill walking, several statistically significant differences were observed between the two conditions with respect to temporo-spatial parameters, 6-DOF knee-joint kinematics, and condylar contact locations and sliding. Thus, caution is advised when making recommendations regarding knee implant performance based on treadmill-measured knee-joint kinematic data. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1634-1643, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  9. Transfer of supinator motor branches to the posterior interosseous nerve in C7-T1 brachial plexus palsy.

    PubMed

    Bertelli, Jayme Augusto; Ghizoni, Marcos Flavio

    2010-07-01

    In C7-T1 palsies of the brachial plexus, shoulder and elbow function are preserved, but finger motion is absent. Finger flexion has been reconstructed by tendon or nerve transfers. Finger extension has been restored ineffectively by attaching the extensor tendons to the distal aspect of the dorsal radius (termed tenodesis) or by tendon transfers. In these palsies, supinator muscle function is preserved, because innervation stems from the C-6 root. The feasibility of transferring supinator branches to the posterior interosseous nerve has been documented in a previous anatomical study. In this paper, the authors report the clinical results of supinator motor nerve transfer to the posterior interosseous nerve in 4 patients with a C7-T1 root lesion. Four adult patients with C7-T1 root lesions underwent surgery between 5 and 7 months postinjury. The patients had preserved motion of the shoulder, elbow, and wrist, but they had complete palsy of finger motion. They underwent finger flexion reconstruction via transfer of the brachialis muscle, and finger and thumb extension were restored by transferring the supinator motor branches to the posterior interosseous nerve. This nerve transfer was performed through an incision over the proximal third of the radius. Dissection was carried out between the extensor carpi radialis brevis and the extensor digitorum communis. The patients were followed up as per regular protocol and underwent a final evaluation 12 months after surgery. To document the extent of recovery, the authors assessed the degree of active metacarpophalangeal joint extension of the long fingers. The thumb span was evaluated by measuring the distance between the thumb pulp and the lateral aspect of the index finger. Surgery to transfer the supinator motor branches to the posterior interosseous nerve was straightforward. Twelve months after surgery, all patients were capable of opening their hand and could fully extend their metacarpophalangeal joints. The

  10. Factors affecting results of fluoroscopy-guided facet joint injection: Probable differences in the outcome of treatment between pure facet joint hypertrophy and concomitant diseases.

    PubMed

    Albayrak, Akif; Ozkul, Baris; Balioglu, Mehmet Bulent; Atici, Yunus; Gultekin, Muhammet Zeki; Albayrak, Merih Dilan

    2016-01-01

    Retrospective cohort study. Facet joints are considered a common source of chronic low-back pain. To determine whether pathogens related to the facet joint arthritis have any effect on treatment failure. Facet joint injection was applied to 94 patients treated at our hospital between 2011 and 2012 (mean age 59.5 years; 80 women and 14 men). For the purpose of analysis, the patients were divided into two groups. Patients who only had facet hypertrophy were placed in group A (47 patients, 41 women and 6 men, mean age 55.3 years) and patients who had any additional major pathology to facet hypertrophy were placed in group B (47 patients, 39 women and 8 men, mean age 58.9 years). Injections were applied around the facet joint under surgical conditions utilizing fluoroscopy device guidance. A mixture of methylprednisolone and lidocaine was used as the injection ingredient. In terms of Oswestry Disability Index (ODI) and visual analog scale (VAS) scores, no significant difference was found between preinjection and immediate postinjection values in both groups, and the scores of group A patients were significantly lower (P < 0.005) compared with that of group B patients at the end of the third, sixth, and twelfth month. For low-back pain caused by facet hypertrophy, steroid injection around the facet joint is an effective treatment, but if there is an existing major pathology, it is not as effective.

  11. Pure Varus Injury to the Knee Joint.

    PubMed

    Yoo, Jae Ho; Lee, Jung Ha; Chang, Chong Bum

    2015-06-01

    A 30-year-old male was involved in a car accident. Radiographs revealed a depressed marginal fracture of the medial tibial plateau and an avulsion fracture of the fibular head. Magnetic resonance imaging showed avulsion fracture of Gerdy's tubercle, injury to the posterior cruciate ligament (PCL), posterior horn of the medial meniscus, and the attachments of the lateral collateral ligament and the biceps femoris tendon. The depressed fracture of the medial tibial plateau was elevated and stabilized using a cannulated screw and washer. The injured lateral and posterolateral corner (PLC) structures were repaired and augmented by PLC reconstruction. However, the avulsion fracture of Gerdy's tubercle was not fixed because it was minimally displaced and the torn PCL was also not repaired or reconstructed. We present a unique case of pure varus injury to the knee joint. This case contributes to our understanding of the mechanism of knee injury and provides insight regarding appropriate treatment plans for this type of injury.

  12. Modeling Finite-Time Failure Probabilities in Risk Analysis Applications.

    PubMed

    Dimitrova, Dimitrina S; Kaishev, Vladimir K; Zhao, Shouqi

    2015-10-01

    In this article, we introduce a framework for analyzing the risk of systems failure based on estimating the failure probability. The latter is defined as the probability that a certain risk process, characterizing the operations of a system, reaches a possibly time-dependent critical risk level within a finite-time interval. Under general assumptions, we define two dually connected models for the risk process and derive explicit expressions for the failure probability and also the joint probability of the time of the occurrence of failure and the excess of the risk process over the risk level. We illustrate how these probabilistic models and results can be successfully applied in several important areas of risk analysis, among which are systems reliability, inventory management, flood control via dam management, infectious disease spread, and financial insolvency. Numerical illustrations are also presented. © 2015 Society for Risk Analysis.

  13. Neural dynamics of reward probability coding: a Magnetoencephalographic study in humans

    PubMed Central

    Thomas, Julie; Vanni-Mercier, Giovanna; Dreher, Jean-Claude

    2013-01-01

    Prediction of future rewards and discrepancy between actual and expected outcomes (prediction error) are crucial signals for adaptive behavior. In humans, a number of fMRI studies demonstrated that reward probability modulates these two signals in a large brain network. Yet, the spatio-temporal dynamics underlying the neural coding of reward probability remains unknown. Here, using magnetoencephalography, we investigated the neural dynamics of prediction and reward prediction error computations while subjects learned to associate cues of slot machines with monetary rewards with different probabilities. We showed that event-related magnetic fields (ERFs) arising from the visual cortex coded the expected reward value 155 ms after the cue, demonstrating that reward value signals emerge early in the visual stream. Moreover, a prediction error was reflected in ERF peaking 300 ms after the rewarded outcome and showing decreasing amplitude with higher reward probability. This prediction error signal was generated in a network including the anterior and posterior cingulate cortex. These findings pinpoint the spatio-temporal characteristics underlying reward probability coding. Together, our results provide insights into the neural dynamics underlying the ability to learn probabilistic stimuli-reward contingencies. PMID:24302894

  14. Arthroscopic sternoclavicular joint resection arthroplasty: a technical note and illustrated case report.

    PubMed

    Warth, Ryan J; Lee, Jared T; Campbell, Kevin J; Millett, Peter J

    2014-02-01

    Open resection arthroplasty of the sternoclavicular (SC) joint has historically provided good long-term results in patients with symptomatic osteoarthritis of the SC joint. However, the procedure is rarely performed because of the risk of injury to vital mediastinal structures and concern regarding postoperative joint instability. Arthroscopic decompression of the SC joint has therefore emerged as a potential treatment option because of many recognized advantages including minimal tissue dissection, maintenance of joint stability, avoidance of posterior SC joint dissection, expeditious recovery, and improved cosmesis. There are, however, safety concerns given the proximity of neurovascular structures. In this article we demonstrate a technique for arthroscopic SC joint resection arthroplasty in a 26-year-old active man with bilateral, painful, idiopathic degenerative SC joint osteoarthritis. This case also highlights the pearls and pitfalls of arthroscopic resection arthroplasty for the SC joint. There were no perioperative complications. Four months postoperatively, the patient had returned to full activities, including weightlifting, without pain or evidence of SC joint instability. One year postoperatively, the patient showed substantial improvements in the American Shoulder and Elbow Surgeons score; Single Assessment Numeric Evaluation score; Quick Disabilities of the Arm, Shoulder and Hand score; and Short Form 12 Physical Component Summary score over preoperative baseline values.

  15. Scalable Joint Models for Reliable Uncertainty-Aware Event Prediction.

    PubMed

    Soleimani, Hossein; Hensman, James; Saria, Suchi

    2017-08-21

    Missing data and noisy observations pose significant challenges for reliably predicting events from irregularly sampled multivariate time series (longitudinal) data. Imputation methods, which are typically used for completing the data prior to event prediction, lack a principled mechanism to account for the uncertainty due to missingness. Alternatively, state-of-the-art joint modeling techniques can be used for jointly modeling the longitudinal and event data and compute event probabilities conditioned on the longitudinal observations. These approaches, however, make strong parametric assumptions and do not easily scale to multivariate signals with many observations. Our proposed approach consists of several key innovations. First, we develop a flexible and scalable joint model based upon sparse multiple-output Gaussian processes. Unlike state-of-the-art joint models, the proposed model can explain highly challenging structure including non-Gaussian noise while scaling to large data. Second, we derive an optimal policy for predicting events using the distribution of the event occurrence estimated by the joint model. The derived policy trades-off the cost of a delayed detection versus incorrect assessments and abstains from making decisions when the estimated event probability does not satisfy the derived confidence criteria. Experiments on a large dataset show that the proposed framework significantly outperforms state-of-the-art techniques in event prediction.

  16. Congenital basis of posterior fossa anomalies

    PubMed Central

    Cotes, Claudia; Bonfante, Eliana; Lazor, Jillian; Jadhav, Siddharth; Caldas, Maria; Swischuk, Leonard

    2015-01-01

    The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies. PMID:26246090

  17. Muscular Activation During Plyometric Exercises in 90° of Glenohumeral Joint Abduction

    PubMed Central

    Ellenbecker, Todd S.; Sueyoshi, Tetsuro; Bailie, David S.

    2015-01-01

    Background: Plyometric exercises are frequently used to increase posterior rotator cuff and periscapular muscle strength and simulate demands and positional stresses in overhead athletes. The purpose of this study was to provide descriptive data on posterior rotator cuff and scapular muscle activation during upper extremity plyometric exercises in 90° of glenohumeral joint abduction. Hypothesis: Levels of muscular activity in the posterior rotator cuff and scapular stabilizers will be high during plyometric shoulder exercises similar to previously reported electromyographic (EMG) levels of shoulder rehabilitation exercises. Study Design: Descriptive laboratory study. Methods: Twenty healthy subjects were tested using surface EMG during the performance of 2 plyometric shoulder exercises: prone external rotation (PERP) and reverse catch external rotation (RCP) using a handheld medicine ball. Electrode application included the upper and lower trapezius (UT and LT, respectively), serratus anterior (SA), infraspinatus (IN), and the middle and posterior deltoid (MD and PD, respectively) muscles. A 10-second interval of repetitive plyometric exercise (PERP) and 3 repetitions of RCP were sampled. Peak and average normalized EMG data were generated. Results: Normalized peak and average IN activity ranged between 73% and 102% and between 28% and 52% during the plyometric exercises, respectively, with peak and average LT activity measured between 79% and 131% and between 31% and 61%. SA activity ranged between 76% and 86% for peak and between 35% and 37% for average activity. Muscular activity levels in the MD and PD ranged between 49% and 72% and between 12% and 33% for peak and average, respectively. Conclusion: Moderate to high levels of muscular activity were measured in the rotator cuff and scapular stabilizers during these plyometric exercises with the glenohumeral joint abducted 90°. PMID:25553216

  18. Innervation of the wrist joint and surgical perspectives of denervation.

    PubMed

    Van de Pol, Gerrit J; Koudstaal, Maarten J; Schuurman, Arnold H; Bleys, Ronald L A W

    2006-01-01

    Because our experience with the techniques used in denervation surgery of the wrist joint often has proven insufficient in treating chronic pain we conducted an anatomic study to clarify the exact contributions of the nerves supplying the wrist joint. Our goal was to reveal all periosteal and capsular nerve connections and if necessary adjust our technique used in denervation surgery. Innervation of the wrist joint was investigated by microdissection and histologic examination of 18 human wrists. An acetylcholinesterase method was used to identify the nerves, both in whole-mount preparations and in sections. We found that the main innervation to the wrist capsule and periosteal nerve network came from the anterior interosseous nerve, lateral antebrachial cutaneous nerve, and posterior interosseous nerve. The palmar cutaneous branch of the median nerve, the deep branch of the ulnar nerve, the superficial branch of the radial nerve, and the dorsal branch of the ulnar nerve also were found to have connections with the capsule. The periosteal nerve branches did not appear to play a major role in the innervation of the capsule and ligaments; here the specific articular nerve branches proved more important. The posterior and medial antebrachial cutaneous nerves did not connect to the wrist capsule or periosteum but rather terminated in the extensor and flexor retinaculum. Based on our findings we propose to denervate the wrist by making 2 incisions. With one palmar and one dorsal incision it should be possible to disconnect the periosteum from the capsule and interrupt the majority of the capsular nerve branches.

  19. Treatment of The Posterior Unstable Shoulder

    PubMed Central

    Alepuz, Eduardo Sánchez

    2017-01-01

    Background: It is estimated that approximately 5% of glenohumeral instabilities are posterior. There are a number of controversies regarding therapeutic approaches for these patients. Methods: We analyse the main surgery alternatives for the treatment of the posterior shoulder instability. We did a research of the publications related with posterior glenohumeral instability. Results: There are conservative and surgical treatment options. Conservative treatment has positive results in most patients, with around 65 to 80% of cases showing recurrent posterior dislocation. There are multiple surgical techniques, both open and arthroscopic, for the treatment of posterior glenohumeral instability. There are procedures that aim to repair bone defects and others that aim to repair soft tissues and capsulolabral injuries. The treatment should be planned according to each case on an individual basis according to the patient characteristics and the injury type. Surgical treatment is indicated in patients with functional limitations arising from instability and/or pain that have not improved with rehabilitation treatment. The indications for arthroscopic treatment are recurrent posterior subluxation caused by injury of the labrum or the capsulolabral complex; recurrent posterior subluxation caused by capsuloligamentous laxity or capsular redundancy; and multidirectional instability with posterior instability as a primary component. Arthroscopic assessment will help identify potential injuries associated with posterior instability such as bone lesions or defects and lesions or defects of soft tissues. The main indications for open surgery would be in cases of Hill Sachs lesions or broad reverse Bankart lesions not accessible by arthroscopy. We indicated non-anatomical techniques (McLaughlin or its modifications) for reverse Hill-Sachs lesions with impairment of the articular surface between 20% and 50%. Disimpaction of the fracture and placement of bone graft (allograft or

  20. Effect of Tibial Posterior Slope on Knee Kinematics, Quadriceps Force, and Patellofemoral Contact Force After Posterior-Stabilized Total Knee Arthroplasty.

    PubMed

    Okamoto, Shigetoshi; Mizu-uchi, Hideki; Okazaki, Ken; Hamai, Satoshi; Nakahara, Hiroyuki; Iwamoto, Yukihide

    2015-08-01

    We used a musculoskeletal model validated with in vivo data to evaluate the effect of tibial posterior slope on knee kinematics, quadriceps force, and patellofemoral contact force after posterior-stabilized total knee arthroplasty. The maximum quadriceps force and patellofemoral contact force decreased with increasing posterior slope. Anterior sliding of the tibial component and anterior impingement of the anterior aspect of the tibial post were observed with tibial posterior slopes of at least 5° and 10°, respectively. Increased tibial posterior slope contributes to improved exercise efficiency during knee extension, however excessive tibial posterior slope should be avoided to prevent knee instability. Based on our computer simulation we recommend tibial posterior slopes of less than 5° in posterior-stabilized total knee arthroplasty. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Joint torques and joint reaction forces during squatting with a forward or backward inclined Smith machine.

    PubMed

    Biscarini, Andrea; Botti, Fabio M; Pettorossi, Vito E

    2013-02-01

    We developed a biomechanical model to determine the joint torques and loadings during squatting with a backward/forward-inclined Smith machine. The Smith squat allows a large variety of body positioning (trunk tilt, foot placement, combinations of joint angles) and easy control of weight distribution between forefoot and heel. These distinctive aspects of the exercise can be managed concurrently with the equipment inclination selected to unload specific joint structures while activating specific muscle groups. A backward (forward) equipment inclination decreases (increases) knee torque, and compressive tibiofemoral and patellofemoral forces, while enhances (depresses) hip and lumbosacral torques. For small knee flexion angles, the strain-force on the posterior cruciate ligament increases (decreases) with a backward (forward) equipment inclination, whereas for large knee flexion angles, this behavior is reversed. In the 0 to 60 degree range of knee flexion angles, loads on both cruciate ligaments may be simultaneously suppressed by a 30 degree backward equipment inclination and selecting, for each value of the knee angle, specific pairs of ankle and hip angles. The anterior cruciate ligament is safely maintained unloaded by squatting with backward equipment inclination and uniform/forward foot weight distribution. The conditions for the development of anterior cruciate ligament strain forces are clearly explained.

  2. Supernova Cosmology Inference with Probabilistic Photometric Redshifts (SCIPPR)

    NASA Astrophysics Data System (ADS)

    Peters, Christina; Malz, Alex; Hlozek, Renée

    2018-01-01

    The Bayesian Estimation Applied to Multiple Species (BEAMS) framework employs probabilistic supernova type classifications to do photometric SN cosmology. This work extends BEAMS to replace high-confidence spectroscopic redshifts with photometric redshift probability density functions, a capability that will be essential in the era the Large Synoptic Survey Telescope and other next-generation photometric surveys where it will not be possible to perform spectroscopic follow up on every SN. We present the Supernova Cosmology Inference with Probabilistic Photometric Redshifts (SCIPPR) Bayesian hierarchical model for constraining the cosmological parameters from photometric lightcurves and host galaxy photometry, which includes selection effects and is extensible to uncertainty in the redshift-dependent supernova type proportions. We create a pair of realistic mock catalogs of joint posteriors over supernova type, redshift, and distance modulus informed by photometric supernova lightcurves and over redshift from simulated host galaxy photometry. We perform inference under our model to obtain a joint posterior probability distribution over the cosmological parameters and compare our results with other methods, namely: a spectroscopic subset, a subset of high probability photometrically classified supernovae, and reducing the photometric redshift probability to a single measurement and error bar.

  3. Bony landmark between the attachment of the medial meniscus posterior root and the posterior cruciate ligament: CT and MR imaging assessment.

    PubMed

    Fujii, Masataka; Furumatsu, Takayuki; Miyazawa, Shinichi; Kodama, Yuya; Hino, Tomohito; Kamatsuki, Yusuke; Ozaki, Toshifumi

    2017-08-01

    (1) To reveal the prevalence of the bony recess (posterior dimple) and (2) to determine the position of the posterior dimple on the tibial plateau using three-dimensional computed tomography (3DCT). In this study, a retrospective review of 112 patients was performed to identify the posterior dimple and to evaluate its position on 3DCT. Magnetic resonance images (MRIs) were also used to determine the positional relationship among the posterior cruciate ligament (PCL), medial meniscus posterior insertion (MMPI), and posterior dimple. The posterior dimple was observed in 100 of 112 knees (89.3%) on 3DCT. The center of the posterior dimple was 13.6 ± 0.8 mm from the medial tibial eminence apex. MRI showed that the posterior dimple separated the tibial attachment of the PCL and MMPI. This is the first study to discuss the prevalence and position of the bony recess in the posterior intercondylar fossa.

  4. Statistical learning of action: the role of conditional probability.

    PubMed

    Meyer, Meredith; Baldwin, Dare

    2011-12-01

    Identification of distinct units within a continuous flow of human action is fundamental to action processing. Such segmentation may rest in part on statistical learning. In a series of four experiments, we examined what types of statistics people can use to segment a continuous stream involving many brief, goal-directed action elements. The results of Experiment 1 showed no evidence for sensitivity to conditional probability, whereas Experiment 2 displayed learning based on joint probability. In Experiment 3, we demonstrated that additional exposure to the input failed to engender sensitivity to conditional probability. However, the results of Experiment 4 showed that a subset of adults-namely, those more successful at identifying actions that had been seen more frequently than comparison sequences-were also successful at learning conditional-probability statistics. These experiments help to clarify the mechanisms subserving processing of intentional action, and they highlight important differences from, as well as similarities to, prior studies of statistical learning in other domains, including language.

  5. Sensory innervation of the temporomandibular joint in the mouse.

    PubMed

    Dreessen, D; Halata, Z; Strasmann, T

    1990-01-01

    The sensory innervation of the temporomandibular joints (TMJs) of 8 STR/IN mice was investigated by means of light and electron microscopy. Through the cutting of complete semithin sections in series it was possible to investigate the joints thoroughly. Additionally, one joint with its nerve supply was reconstructed three-dimensionally with a computerized three-dimensional programme. The reconstruction was based on one complete semithin section series. The joint's nerve supply originates from the nervus auriculotemporalis and additionally from motor branches of the n. mandibularis: n. massetericus, n. pterygoideus lateralis and the nn. temporales posteriores. The greatest number of nerve fibres and endings is located in the dorsolateral part of the joint capsule. They lie only in the stratum fibrosum and subsynovially. Neither the stratum synoviale nor the discus articularis contain any nerve fibres or endings, whereas the peri-articular loose connective tissue is richly innervated. The only type of nerve ending observed within the joint was the free nerve ending, which is assumed to serve not only as a nociceptor but also as a polymodal mechanoreceptor. Merely within the insertion of the musculus pterygoideus lateralis at the collum mandibulae single stretch receptors of the Ruffini type were observed. Ultrastructurally, they correspond to those described in the cat's knee joint. Neither lamellated nor nerve endings of the Golgi or Pacini type were observed in the joint or in the peri-articular connective tissue. The unexpected paucity of nerve fibres and endings in the TMJ itself of the mouse suggests that the afferent information from the joint is less important for position sense and movement than the afferent information from muscles, tendons and periodontal ligaments.

  6. A short walk in quantum probability

    NASA Astrophysics Data System (ADS)

    Hudson, Robin

    2018-04-01

    This is a personal survey of aspects of quantum probability related to the Heisenberg commutation relation for canonical pairs. Using the failure, in general, of non-negativity of the Wigner distribution for canonical pairs to motivate a more satisfactory quantum notion of joint distribution, we visit a central limit theorem for such pairs and a resulting family of quantum planar Brownian motions which deform the classical planar Brownian motion, together with a corresponding family of quantum stochastic areas. This article is part of the themed issue `Hilbert's sixth problem'.

  7. A short walk in quantum probability.

    PubMed

    Hudson, Robin

    2018-04-28

    This is a personal survey of aspects of quantum probability related to the Heisenberg commutation relation for canonical pairs. Using the failure, in general, of non-negativity of the Wigner distribution for canonical pairs to motivate a more satisfactory quantum notion of joint distribution, we visit a central limit theorem for such pairs and a resulting family of quantum planar Brownian motions which deform the classical planar Brownian motion, together with a corresponding family of quantum stochastic areas.This article is part of the themed issue 'Hilbert's sixth problem'. © 2018 The Author(s).

  8. Fast approximation for joint optimization of segmentation, shape, and location priors, and its application in gallbladder segmentation.

    PubMed

    Saito, Atsushi; Nawano, Shigeru; Shimizu, Akinobu

    2017-05-01

    This paper addresses joint optimization for segmentation and shape priors, including translation, to overcome inter-subject variability in the location of an organ. Because a simple extension of the previous exact optimization method is too computationally complex, we propose a fast approximation for optimization. The effectiveness of the proposed approximation is validated in the context of gallbladder segmentation from a non-contrast computed tomography (CT) volume. After spatial standardization and estimation of the posterior probability of the target organ, simultaneous optimization of the segmentation, shape, and location priors is performed using a branch-and-bound method. Fast approximation is achieved by combining sampling in the eigenshape space to reduce the number of shape priors and an efficient computational technique for evaluating the lower bound. Performance was evaluated using threefold cross-validation of 27 CT volumes. Optimization in terms of translation of the shape prior significantly improved segmentation performance. The proposed method achieved a result of 0.623 on the Jaccard index in gallbladder segmentation, which is comparable to that of state-of-the-art methods. The computational efficiency of the algorithm is confirmed to be good enough to allow execution on a personal computer. Joint optimization of the segmentation, shape, and location priors was proposed, and it proved to be effective in gallbladder segmentation with high computational efficiency.

  9. Height probabilities in the Abelian sandpile model on the generalized finite Bethe lattice

    NASA Astrophysics Data System (ADS)

    Chen, Haiyan; Zhang, Fuji

    2013-08-01

    In this paper, we study the sandpile model on the generalized finite Bethe lattice with a particular boundary condition. Using a combinatorial method, we give the exact expressions for all single-site probabilities and some two-site joint probabilities. As a by-product, we prove that the height probabilities of bulk vertices are all the same for the Bethe lattice with certain given boundary condition, which was found from numerical evidence by Grassberger and Manna ["Some more sandpiles," J. Phys. (France) 51, 1077-1098 (1990)], 10.1051/jphys:0199000510110107700 but without a proof.

  10. The effects of progressive lateralization of the joint center of rotation of reverse total shoulder implants.

    PubMed

    Costantini, Oren; Choi, Daniel S; Kontaxis, Andreas; Gulotta, Lawrence V

    2015-07-01

    There has been a renewed interest in lateralizing the center of rotation (CoR) in implants used in reverse shoulder arthroplasty. The aim of this study was to determine the sensitivity of lateralization of the CoR on the glenohumeral joint contact forces, muscle moment arms, torque across the bone-implant interface, and the stability of the implant. A 3-dimensional virtual model was used to investigate how lateralization affects deltoid muscle moment arm and glenohumeral joint contact forces. This model was virtually implanted with 5 progressively lateralized reverse shoulder prostheses. The joint contact loads and deltoid moment arms were calculated for each lateralization over the course of 3 simulated standard humerothoracic motions. Lateralization of the CoR leads to an increase in the overall joint contact forces across the glenosphere. Most of this increased loading occurred through compression, although increases in anterior/posterior and superior/inferior shear were also observed. Moment arms of the deltoid consistently decreased with lateralization. Bending moments at the implant interface increased with lateralization. Progressive lateralization resulted in improved stability ratios. Lateralization results in increased joint loading. Most of that loading occurs through compression, although there were also increases in shear forces. Anterior/posterior shear is currently not accounted for in implant fixation studies, leaving its effect on implant fixation unknown. Future studies should incorporate shear forces into their models to more accurately assess fixation methods. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  11. Modified Pull-out Suture in Posterior Root Tear of the Medial Meniscus: Using a Posteromedial Portal.

    PubMed

    Cho, Jin Ho

    2012-06-01

    In cases with root tear of the medial meniscus posterior horn, the meniscus usually can be repaired by a pull out suture technique. However, there is difficulty in manipulating a suture hook via the anteromedial portal and looking through the arthroscopic camera via anterolateral portal in the narrow medial joint space at the same time. This article describes a modified simple pull out suture technique for root tear of the medial meniscus posterior horn using a posteromedial portal that provides a safe and easy handling of the suture hook. Our indications of this technique used in patients with Outerbridge 1-2 arthritic change and minimal varus axis change. Benefits of this technique are simple, less invasive, and reduced operation time by simultaneous suture with a hook via posteromedial portal and pulling of a string with grasper. It may reduce the possibility of an additional chondral or meniscal injury.

  12. Posterior tibial slope in medial opening-wedge high tibial osteotomy: 2-D versus 3-D navigation.

    PubMed

    Yim, Ji Hyeon; Seon, Jong Keun; Song, Eun Kyoo

    2012-10-01

    Although opening-wedge high tibial osteotomy (HTO) is used to correct deformities, it can simultaneously alter tibial slope in the sagittal plane because of the triangular configuration of the proximal tibia, and this undesired change in tibial slope can influence knee kinematics, stability, and joint contact pressure. Therefore, medial opening-wedge HTO is a technically demanding procedure despite the use of 2-dimensional (2-D) navigation. The authors evaluated the posterior tibial slope pre- and postoperatively in patients who underwent navigation-assisted opening-wedge HTO and compared posterior slope changes for 2-D and 3-dimensional (3-D) navigation versions. Patients were randomly divided into 2 groups based on the navigation system used: group A (2-D guidance for coronal alignment; 17 patients) and group B (3-D guidance for coronal and sagittal alignments; 17 patients). Postoperatively, the mechanical axis was corrected to a mean valgus of 2.81° (range, 1°-5.4°) in group A and 3.15° (range, 1.5°-5.6°) in group B. A significant intergroup difference existed for the amount of posterior tibial slope change (Δ slope) pre- and postoperatively (P=.04).Opening-wedge HTO using navigation offers accurate alignment of the lower limb. In particular, the use of 3-D navigation results in significantly less change in the posterior tibial slope postoperatively than does the use of 2-D navigation. Accordingly, the authors recommend the use of 3-D navigation systems because they provide real-time intraoperative information about coronal, sagittal, and transverse axes and guide the maintenance of the native posterior tibial slope. Copyright 2012, SLACK Incorporated.

  13. Joint probabilities of extreme precipitation and wind gusts in Germany

    NASA Astrophysics Data System (ADS)

    von Waldow, H.; Martius, O.

    2012-04-01

    Extreme meteorological events such as storms, heavy rain, floods, droughts and heat waves can have devastating consequences for human health, infrastructure and ecosystems. Concomitantly occurring extreme events might interact synergistically to produce a particularly hazardous impact. The joint occurrence of droughts and heat waves, for example, can have a very different impact on human health and ecosystems both in quantity and quality, than just one of the two extreme events. The co-occurrence of certain types of extreme events is plausible from physical and dynamical considerations, for example heavy precipitation and high wind speeds in the pathway of strong extratropical cyclones. The winter storm Kyrill not only caused wind gust speeds well in excess of 30 m/s across Europe, but also brought 24 h precipitation sums greater than the mean January accumulations in some regions. However, the existence of such compound risks is currently not accounted for by insurance companies, who assume independence of extreme weather events to calculate their premiums. While there are established statistical methods to model the extremes of univariate meteorological variables, the modelling of multidimensional extremes calls for an approach that is tailored to the specific problem at hand. A first step involves defining extreme bivariate wind/precipitation events. Because precipitation and wind gusts caused by the same cyclone or convective cell do not occur at exactly the same location and at the same time, it is necessary to find a sound definition of "extreme compound event" for this case. We present a data driven method to choose appropriate time and space intervals that define "concomitance" for wind and precipitation extremes. Based on station data of wind speed and gridded precipitation data, we arrive at time and space intervals that compare well with the typical time and space scales of extratropical cyclones, i.e. a maximum time lag of 1 day and a maximum distance

  14. Retinoic acid signaling acts via Hox1 to establish the posterior limit of the pharynx in the chordate amphioxus.

    PubMed

    Schubert, Michael; Yu, Jr-Kai; Holland, Nicholas D; Escriva, Hector; Laudet, Vincent; Holland, Linda Z

    2005-01-01

    In the invertebrate chordate amphioxus, as in vertebrates, retinoic acid (RA) specifies position along the anterior/posterior axis with elevated RA signaling in the middle third of the endoderm setting the posterior limit of the pharynx. Here we show that AmphiHox1 is also expressed in the middle third of the developing amphioxus endoderm and is activated by RA signaling. Knockdown of AmphiHox1 function with an antisense morpholino oligonucleotide shows that AmphiHox1 mediates the role of RA signaling in setting the posterior limit of the pharynx by repressing expression of pharyngeal markers in the posterior foregut/midgut endoderm. The spatiotemporal expression of these endodermal genes in embryos treated with RA or the RA antagonist BMS009 indicates that Pax1/9, Pitx and Notch are probably more upstream than Otx and Nodal in the hierarchy of genes repressed by RA signaling. This work highlights the potential of amphioxus, a genomically simple, vertebrate-like invertebrate chordate, as a paradigm for understanding gene hierarchies similar to the more complex ones of vertebrates.

  15. Treatment of Spinal Tuberculosis by Debridement, Interbody Fusion and Internal Fixation via Posterior Approach Only.

    PubMed

    Tang, Ming-xing; Zhang, Hong-qi; Wang, Yu-xiang; Guo, Chao-feng; Liu, Jin-yang

    2016-02-01

    Surgical treatment for spinal tuberculosis includes focal tuberculosis debridement, segmental stability reconstruction, neural decompression and kyphotic deformity correction. For the lesions mainly involved anterior and middle column of the spine, anterior operation of debridement and fusion with internal fixation has been becoming the most frequently used surgical technique for the spinal tuberculosis. However, high risk of structural damage might relate with anterior surgery, such as damage in lungs, heart, kidney, ureter and bowel, and the deformity correction is also limited. Due to the organs are in the front of spine, there are less complications in posterior approach. Spinal pedicle screw passes through the spinal three-column structure, which provides more powerful orthopedic forces compared with the vertebral body screw, and the kyphotic deformity correction effect is better in posterior approach. In this paper, we report a 68-year-old male patient with thoracic tuberculosis who underwent surgical treatment by debridement, interbody fusion and internal fixation via posterior approach only. The patient was placed in prone position under general anesthesia. Posterior midline incision was performed, and the posterior spinal construction was exposed. Then place pedicle screw, and fix one side rod temporarily. Make the side of more bone destruction and larger abscess as lesion debridement side. Resect the unilateral facet joint, and retain contralateral structure integrity. Protect the spinal cord, nerve root. Clear sequestrum, necrotic tissue, abscess of paravertebral and intervertebral space. Specially designed titanium mesh cages or bone blocks were implanted into interbody. Fix both side rods and compress both sides to make the mesh cages and bone blocks tight. Reconstruct posterior column structure with allogeneic bone and autologous bone. Using this technique, the procedures of debridement, spinal cord decompression, deformity correction, bone grafting

  16. Posterior dental size reduction in hominids: the Atapuerca evidence.

    PubMed

    Bermúdez de Castro, J M; Nicolas, M E

    1995-04-01

    In order to reassess previous hypotheses concerning dental size reduction of the posterior teeth during Pleistocene human evolution, current fossil dental evidence is examined. This evidence includes the large sample of hominid teeth found in recent excavations (1984-1993) in the Sima de los Huesos Middle Pleistocene cave site of the Sierra de Atapuerca (Burgos, Spain). The lower fourth premolars and molars of the Atapuerca hominids, probably older than 300 Kyr, have dimensions similar to those of modern humans. Further, these hominids share the derived state of other features of the posterior teeth with modern humans, such as a similar relative molar size and frequent absence of the hypoconulid, thus suggesting a possible case of parallelism. We believe that dietary changes allowed size reduction of the posterior teeth during the Middle Pleistocene, and the present evidence suggests that the selective pressures that operated on the size variability of these teeth were less restrictive than what is assumed by previous models of dental reduction. Thus, the causal relationship between tooth size decrease and changes in food-preparation techniques during the Pleistocene should be reconsidered. Moreover, the present evidence indicates that the differential reduction of the molars cannot be explained in terms of restriction of available growth space. The molar crown area measurements of a modern human sample were also investigated. The results of this study, as well as previous similar analyses, suggest that a decrease of the rate of cell proliferation, which affected the later-forming crown regions to a greater extent, may be the biological process responsible for the general and differential dental size reduction that occurred during human evolution.

  17. Naive Probability: Model-Based Estimates of Unique Events.

    PubMed

    Khemlani, Sangeet S; Lotstein, Max; Johnson-Laird, Philip N

    2015-08-01

    We describe a dual-process theory of how individuals estimate the probabilities of unique events, such as Hillary Clinton becoming U.S. President. It postulates that uncertainty is a guide to improbability. In its computer implementation, an intuitive system 1 simulates evidence in mental models and forms analog non-numerical representations of the magnitude of degrees of belief. This system has minimal computational power and combines evidence using a small repertoire of primitive operations. It resolves the uncertainty of divergent evidence for single events, for conjunctions of events, and for inclusive disjunctions of events, by taking a primitive average of non-numerical probabilities. It computes conditional probabilities in a tractable way, treating the given event as evidence that may be relevant to the probability of the dependent event. A deliberative system 2 maps the resulting representations into numerical probabilities. With access to working memory, it carries out arithmetical operations in combining numerical estimates. Experiments corroborated the theory's predictions. Participants concurred in estimates of real possibilities. They violated the complete joint probability distribution in the predicted ways, when they made estimates about conjunctions: P(A), P(B), P(A and B), disjunctions: P(A), P(B), P(A or B or both), and conditional probabilities P(A), P(B), P(B|A). They were faster to estimate the probabilities of compound propositions when they had already estimated the probabilities of each of their components. We discuss the implications of these results for theories of probabilistic reasoning. © 2014 Cognitive Science Society, Inc.

  18. The value of arthrography in the decision-making process regarding surgery for internal derangement of the temporomandibular joint.

    PubMed

    Nitzan, D W; Dolwick, F M; Marmary, Y

    1991-04-01

    In this study, the clinical and arthrographic findings from 43 internally deranged temporomandibular joints (TMJs) were compared with the intra-surgical observations. In 40 of 43 joints, arthrography did not provide any additional information useful for diagnosis or treatment. In six joints, the problem was misdiagnosed. Only in three joints did arthrography demonstrate the existence of perforation in the posterior attachment that had not been suspected during the clinical examination. Because of the doubtful importance of arthrographic information for the decision-making process, it is suggested that the method be applied only in cases in which clinical examination and plain radiographs have failed to uncover the signs and symptoms indicative of a TMJ disorder.

  19. A concise evidence-based physical examination for diagnosis of acromioclavicular joint pathology: a systematic review.

    PubMed

    Krill, Michael K; Rosas, Samuel; Kwon, KiHyun; Dakkak, Andrew; Nwachukwu, Benedict U; McCormick, Frank

    2018-02-01

    The clinical examination of the shoulder joint is an undervalued diagnostic tool for evaluating acromioclavicular (AC) joint pathology. Applying evidence-based clinical tests enables providers to make an accurate diagnosis and minimize costly imaging procedures and potential delays in care. The purpose of this study was to create a decision tree analysis enabling simple and accurate diagnosis of AC joint pathology. A systematic review of the Medline, Ovid and Cochrane Review databases was performed to identify level one and two diagnostic studies evaluating clinical tests for AC joint pathology. Individual test characteristics were combined in series and in parallel to improve sensitivities and specificities. A secondary analysis utilized subjective pre-test probabilities to create a clinical decision tree algorithm with post-test probabilities. The optimal special test combination to screen and confirm AC joint pathology combined Paxinos sign and O'Brien's Test, with a specificity of 95.8% when performed in series; whereas, Paxinos sign and Hawkins-Kennedy Test demonstrated a sensitivity of 93.7% when performed in parallel. Paxinos sign and O'Brien's Test demonstrated the greatest positive likelihood ratio (2.71); whereas, Paxinos sign and Hawkins-Kennedy Test reported the lowest negative likelihood ratio (0.35). No combination of special tests performed in series or in parallel creates more than a small impact on post-test probabilities to screen or confirm AC joint pathology. Paxinos sign and O'Brien's Test is the only special test combination that has a small and sometimes important impact when used both in series and in parallel. Physical examination testing is not beneficial for diagnosis of AC joint pathology when pretest probability is unequivocal. In these instances, it is of benefit to proceed with procedural tests to evaluate AC joint pathology. Ultrasound-guided corticosteroid injections are diagnostic and therapeutic. An ultrasound-guided AC joint

  20. The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions

    PubMed Central

    Kang, K-T.; Koh, Y-G.; Jung, M.; Nam, J-H.; Son, J.; Lee, Y.H.

    2017-01-01

    Objectives The aim of the current study was to analyse the effects of posterior cruciate ligament (PCL) deficiency on forces of the posterolateral corner structure and on tibiofemoral (TF) and patellofemoral (PF) contact force under dynamic-loading conditions. Methods A subject-specific knee model was validated using a passive flexion experiment, electromyography data, muscle activation, and previous experimental studies. The simulation was performed on the musculoskeletal models with and without PCL deficiency using a novel force-dependent kinematics method under gait- and squat-loading conditions, followed by probabilistic analysis for material uncertain to be considered. Results Comparison of predicted passive flexion, posterior drawer kinematics and muscle activation with experimental measurements showed good agreement. Forces of the posterolateral corner structure, and TF and PF contact forces increased with PCL deficiency under gait- and squat-loading conditions. The rate of increase in PF contact force was the greatest during the squat-loading condition. The TF contact forces increased on both medial and lateral compartments during gait-loading conditions. However, during the squat-loading condition, the medial TF contact force tended to increase, while the lateral TF contact forces decreased. The posterolateral corner structure, which showed the greatest increase in force with deficiency of PCL under both gait- and squat-loading conditions, was the popliteus tendon (PT). Conclusion PCL deficiency is a factor affecting the variability of force on the PT in dynamic-loading conditions, and it could lead to degeneration of the PF joint. Cite this article: K-T. Kang, Y-G. Koh, M. Jung, J-H. Nam, J. Son, Y.H. Lee, S-J. Kim, S-H. Kim. The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions: A computational knee model. Bone Joint Res 2017;6:31–42. DOI: 10.1302/2046-3758.61.BJR-2016-0184.R1

  1. The posterior two-portal approach for reconstruction of scapula fractures: results of 39 patients.

    PubMed

    Pizanis, A; Tosounidis, G; Braun, C; Pohlemann, T; Wirbel, R J

    2013-11-01

    The purpose of this study was to describe the so-called posterior two-portal approach to the scapula in detail and to investigate the clinical outcome of patients with displaced glenoid and scapular neck fractures who were surgically treated using this approach. From February 1992 to August 2008, 39 patients (30 men and nine women; mean age: 53 years) with scapular fractures underwent surgical fixation at our institution. Thirty-three patients had glenoid fractures and six had unstable scapular neck fractures. All patients were treated via the two-portal approach. The reduction was evaluated radiographically, and the clinical results were analysed using the Constant score. The mean follow-up period was 78 months (range: 6-168). In 24 of the 33 glenoid fractures, the reduction was anatomical. The mean Constant score was 82.3 (range: 35-100) points. In one case, an early postoperative wound infection was cured by local revision, and one patient developed posttraumatic osteoarthritis of the acromioclavicular joint after 2 years. Only one patient developed specific glenohumeral degeneration after non-anatomical reduction. The posterior two-portal approach allows for a good visualisation of the posterior scapular neck and the glenoid area, facilitating the reduction and safe internal fixation of dislocated scapular neck and glenoid fractures. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Joint modeling of longitudinal data and discrete-time survival outcome.

    PubMed

    Qiu, Feiyou; Stein, Catherine M; Elston, Robert C

    2016-08-01

    A predictive joint shared parameter model is proposed for discrete time-to-event and longitudinal data. A discrete survival model with frailty and a generalized linear mixed model for the longitudinal data are joined to predict the probability of events. This joint model focuses on predicting discrete time-to-event outcome, taking advantage of repeated measurements. We show that the probability of an event in a time window can be more precisely predicted by incorporating the longitudinal measurements. The model was investigated by comparison with a two-step model and a discrete-time survival model. Results from both a study on the occurrence of tuberculosis and simulated data show that the joint model is superior to the other models in discrimination ability, especially as the latent variables related to both survival times and the longitudinal measurements depart from 0. © The Author(s) 2013.

  3. [Finite element analysis on the effect of lateral wedge insole intervention on the contact characteristics of the subtalar joint].

    PubMed

    Zhou, En-Chang; Tang, Ping; Zhu, Chuan-Ying; Liu, Shi-Ming

    2017-01-25

    To establish a three-dimensional finite element model of the lower limb bones, and investigate the changes of the contact characteristics of the subtalar joint after using laterally wedge insole intervention. Using the reverse modeling technology, the lower limb bones of normal adult volunteers was scanned by CT. Mimics 10.0 and Geomagic Studio 6.0 software were used to reconstruct the 3D morphology of bones and external soft tissue of the feet. The laterally wedge insole was designed in ProE 5.0. And then all the models were imported into Hyperwork 10.0 and meshed, and given the material properties. The finite element analysis was carried out in ABAQUS 6.9. A three-dimensional finite element model of the lower extremity was established, which was consisted of 95 365 nodes and 246 238 elements. The contact area of the standing state of the lower joint was larger than that of the anterior middle joint surface. The peak stress was concentrated in the anterior lateral part of the posterior articular surface, and the average stress value was(3.85±1.03) MPa. Compared with the model of 0°, the contact area of the subtalar joint was reduced accordingly. There was a significant correlation between anterior middle joint | r |=0.964, P =0.008, and posterior articular | r |=0.978, P =0.002. The equivalent stress of 0° model distributed from(3.07±1.14) MPa to(3.85± 1.03) MPa, which had no statistically difference. Compared with the 0° model, the equivalent stress of the anterior and middle joint surfaces of the 8° model was significantly reduced( P <0.05), but the peak stress of the posterior articular surface was significantly increased( P <0.05). In the 12° model, the peak stress was sharply increased to(10.51±3.53) MPa. Compared with 8° model, there was no statistically difference( P <0.05). Although the peak stress was slightly increased in 16° model, but compared with 12° model, there was no statistically differences( P >0.05). Although a certain valgus can be

  4. The ulnar collateral ligament of the human elbow joint. Anatomy, function and biomechanics.

    PubMed Central

    Fuss, F K

    1991-01-01

    The posterior portion of the ulnar collateral ligament, which arises from the posterior surface of the medial epicondyle, is taut in maximal flexion. The anterior portion, which takes its origin from the anterior and inferior surfaces of the epicondyle, contains three functional fibre bundles. One of these is taut in maximal extension, another in intermediate positions between middle position and full flexion while the third bundle is always taut and serves as a guiding bundle. Movements of the elbow joint are checked by the ligaments well before the bony processes forming the jaws of the trochlear notch lock into the corresponding fossae on the humerus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:2050566

  5. Developmental abnormalities of the posterior pituitary gland.

    PubMed

    di Iorgi, Natascia; Secco, Andrea; Napoli, Flavia; Calandra, Erika; Rossi, Andrea; Maghnie, Mohamad

    2009-01-01

    While the molecular mechanisms of anterior pituitary development are now better understood than in the past, both in animals and in humans, little is known about the mechanisms regulating posterior pituitary development. The posterior pituitary gland is formed by the evagination of neural tissue from the floor of the third ventricle. It consists of the distal axons of the hypothalamic magnocellular neurones that shape the neurohypophysis. After its downward migration, it is encapsulated together with the ascending ectodermal cells of Rathke's pouch which form the anterior pituitary. By the end of the first trimester, this development is completed and vasopressin and oxytocin can be detected in neurohypophyseal tissue. Abnormal posterior pituitary migration such as the ectopic posterior pituitary lobe appearing at the level of median eminence or along the pituitary stalk have been reported in idiopathic GH deficiency or in subjects with HESX1, LHX4 and SOX3 gene mutations. Another intriguing feature of abnormal posterior pituitary development involves genetic forms of posterior pituitary neurodegeneration that have been reported in autosomal-dominant central diabetes insipidus and Wolfram disease. Defining the phenotype of the posterior pituitary gland can have significant clinical implications for management and counseling, as well as providing considerable insight into normal and abnormal mechanisms of posterior pituitary development in humans.

  6. Ventral C1 Fracture Combined with Congenital Posterior Cleft: What to Do?

    PubMed

    Gembruch, Oliver; Dammann, Philipp; Schoemberg, Tobias; Ahmadipour, Yahya; Payer, Michael; Sure, Ulrich; Tessitore, Enrico; Özkan, Neriman

    2018-01-01

     We present a treatment approach for a rare condition of patients with a ventral C1 fracture and a congenital cleft in the posterior arch (half-ring Jefferson fracture) with an intact transverse atlantal ligament. Our technique aims to achieve stability of the atlanto-occipital and atlantoaxial joints while preserving mobility of the upper cervical spine.  Two male patients, 43 years and 29 years of age, respectively, were admitted to our hospital due to a fracture of the ventral arch of the atlas with no damage of the transverse atlantal ligament. Both men also presented a congenital cleft of the posterior arch. Initial conservative management with a halo-thoracic vest was performed in one case and failed. As a result, surgical treatment was performed in both cases using bilateral C1 mass screws and a transverse connector.  The patients showed no neurologic deficits on follow-up examination 4 weeks after surgery with a full range of head and neck motion. Computed tomography (CT) showed no dislocation of the implanted material with good dorsal alignment and a stable ventral fracture distance. Follow-up CT showed osseous stability in both cases with the beginning of bony ossification of the bone graft.  Isolated instable fractures of the ventral arch of the atlas with a congenital cleft of the posterior arch with no damage of the transverse atlantal ligament can be stabilized using bilateral C1 mass screws and a transverse connector preserving upper cervical spine mobility. Georg Thieme Verlag KG Stuttgart · New York.

  7. The Probable Explanation for the Low Friction of Natural Joints.

    PubMed

    Pawlak, Zenon; Urbaniak, Wieslaw; Hagner-Derengowska, Magdalena; Hagner, Wojciech

    2015-04-01

    The surface of an articular cartilage, coated with phospholipid (PL) bilayers, plays an important role in its lubrication and movement. Intact (normal) and depleted surfaces of the joint were modelled and the pH influence on the surface interfacial energy, wettability and friction were investigated. In the experiments, the deterioration of the PL bilayer was controlled by its wettability and the applied friction. The surrounding fluid of an undamaged articular cartilage, the synovial fluid, has a pH value of approximately 7.4. Buffer solutions were formulated to represent the synovial fluid with various pH values. It was found that the surface interfacial energy was stabilised at its lowest values when the pH varied between 6.5 and 9.5. These results suggested that as the PL bilayers deteriorated, the hydration repulsion mechanism became less effective as friction increased. The decreased number of bilayers changed the wettability and lowered PL lubricant properties.

  8. Modulation of cognitive control levels via manipulation of saccade trial-type probability assessed with event-related BOLD fMRI.

    PubMed

    Pierce, Jordan E; McDowell, Jennifer E

    2016-02-01

    Cognitive control supports flexible behavior adapted to meet current goals and can be modeled through investigation of saccade tasks with varying cognitive demands. Basic prosaccades (rapid glances toward a newly appearing stimulus) are supported by neural circuitry, including occipital and posterior parietal cortex, frontal and supplementary eye fields, and basal ganglia. These trials can be contrasted with complex antisaccades (glances toward the mirror image location of a stimulus), which are characterized by greater functional magnetic resonance imaging (MRI) blood oxygenation level-dependent (BOLD) signal in the aforementioned regions and recruitment of additional regions such as dorsolateral prefrontal cortex. The current study manipulated the cognitive demands of these saccade tasks by presenting three rapid event-related runs of mixed saccades with a varying probability of antisaccade vs. prosaccade trials (25, 50, or 75%). Behavioral results showed an effect of trial-type probability on reaction time, with slower responses in runs with a high antisaccade probability. Imaging results exhibited an effect of probability in bilateral pre- and postcentral gyrus, bilateral superior temporal gyrus, and medial frontal gyrus. Additionally, the interaction between saccade trial type and probability revealed a strong probability effect for prosaccade trials, showing a linear increase in activation parallel to antisaccade probability in bilateral temporal/occipital, posterior parietal, medial frontal, and lateral prefrontal cortex. In contrast, antisaccade trials showed elevated activation across all runs. Overall, this study demonstrated that improbable performance of a typically simple prosaccade task led to augmented BOLD signal to support changing cognitive control demands, resulting in activation levels similar to the more complex antisaccade task. Copyright © 2016 the American Physiological Society.

  9. On the joint spectral density of bivariate random sequences. Thesis Technical Report No. 21

    NASA Technical Reports Server (NTRS)

    Aalfs, David D.

    1995-01-01

    For univariate random sequences, the power spectral density acts like a probability density function of the frequencies present in the sequence. This dissertation extends that concept to bivariate random sequences. For this purpose, a function called the joint spectral density is defined that represents a joint probability weighing of the frequency content of pairs of random sequences. Given a pair of random sequences, the joint spectral density is not uniquely determined in the absence of any constraints. Two approaches to constraining the sequences are suggested: (1) assume the sequences are the margins of some stationary random field, (2) assume the sequences conform to a particular model that is linked to the joint spectral density. For both approaches, the properties of the resulting sequences are investigated in some detail, and simulation is used to corroborate theoretical results. It is concluded that under either of these two constraints, the joint spectral density can be computed from the non-stationary cross-correlation.

  10. Sacroiliac joint dysfunction as a reason for the development of acetabular retroversion: a new theory.

    PubMed

    Cibulka, Michael T

    2014-05-01

    Acetabular retroversion has been recently implicated as an important factor in the development of femoral acetabular impingement and hip osteoarthritis. The proper function of the hip joint requires that the anatomic features of the acetabulum and femoral head complement one another. In acetabular retroversion, the alignment of the acetabulum is altered where it opens in a posterolaterally instead of anterior direction. Changes in acetabular orientation can occur with alterations in pelvic tilt (anterior/posterior), and pelvic rotation (left/right). An overlooked problem that alters pelvic tilt and rotation, often seen by physical therapists, is sacroiliac joint dysfunction. A unique feature that develops in patients with sacroiliac joint dysfunction (SIJD) is asymmetry between the left and right innominate bones that can alter pelvic tilt and rotation. This article puts forth a theory suggesting that acetabular retroversion may be produced by sacroiliac joint dysfunction.

  11. Effects of neuromuscular joint facilitation on bridging exercises with respect to deep muscle changes.

    PubMed

    Zhou, Bin; Huang, QiuChen; Zheng, Tao; Huo, Ming; Maruyama, Hitoshi

    2015-05-01

    [Purpose] This study examined the effects of neuromuscular joint facilitation on bridging exercises by assessing the cross-sectional area of the multifidus muscle and thickness of the musculus transversus abdominis. [Subjects] Twelve healthy men. [Methods] Four exercises were evaluated: (a) supine resting, (b) bridging resistance exercise involving posterior pelvic tilting, (c) bridging resistance exercise involving anterior pelvic tilting, and (d) bridging resistance exercise involving neuromuscular joint facilitation. The cross-sectional area of the multifidus muscle and thickness of the musculus transversus abdominis were measured during each exercise. [Results] The cross-sectional area of the multifidus muscle and thickness of the musculus transversus abdominis were significantly greater in the neuromuscular joint facilitation group than the others. [Conclusion] Neuromuscular joint facilitation intervention improves the function of deep muscles such as the multifidus muscle and musculus transversus abdominis. Therefore, it can be recommended for application in clinical treatments such as that for back pain.

  12. Posterior cruciate ligament: anatomy, biomechanics, and outcomes.

    PubMed

    Voos, James E; Mauro, Craig S; Wente, Todd; Warren, Russell F; Wickiewicz, Thomas L

    2012-01-01

    The optimal treatment of posterior cruciate ligament ruptures remains controversial despite numerous recent basic science advances on the topic. The current literature on the anatomy, biomechanics, and clinical outcomes of posterior cruciate ligament reconstruction is reviewed. Recent studies have quantified the anatomic location and biomechanical contribution of each of the 2 posterior cruciate ligament bundles on tunnel placement and knee kinematics during reconstruction. Additional laboratory and cadaveric studies have suggested double-bundle reconstructions of the posterior cruciate ligament may better restore normal knee kinematics than single-bundle reconstructions although clinical outcomes have not revealed such a difference. Tibial inlay posterior cruciate ligament reconstructions (either open or arthroscopic) are preferred by many authors to avoid the "killer turn" and graft laxity with cyclic loading. Posterior cruciate ligament reconstruction improves subjective patient outcomes and return to sport although stability and knee kinematics may not return to normal.

  13. Farm Management, Environment, and Weather Factors Jointly Affect the Probability of Spinach Contamination by Generic Escherichia coli at the Preharvest Stage

    PubMed Central

    Navratil, Sarah; Gregory, Ashley; Bauer, Arin; Srinath, Indumathi; Szonyi, Barbara; Nightingale, Kendra; Anciso, Juan; Jun, Mikyoung; Han, Daikwon; Lawhon, Sara; Ivanek, Renata

    2014-01-01

    The National Resources Information (NRI) databases provide underutilized information on the local farm conditions that may predict microbial contamination of leafy greens at preharvest. Our objective was to identify NRI weather and landscape factors affecting spinach contamination with generic Escherichia coli individually and jointly with farm management and environmental factors. For each of the 955 georeferenced spinach samples (including 63 positive samples) collected between 2010 and 2012 on 12 farms in Colorado and Texas, we extracted variables describing the local weather (ambient temperature, precipitation, and wind speed) and landscape (soil characteristics and proximity to roads and water bodies) from NRI databases. Variables describing farm management and environment were obtained from a survey of the enrolled farms. The variables were evaluated using a mixed-effect logistic regression model with random effects for farm and date. The model identified precipitation as a single NRI predictor of spinach contamination with generic E. coli, indicating that the contamination probability increases with an increasing mean amount of rain (mm) in the past 29 days (odds ratio [OR] = 3.5). The model also identified the farm's hygiene practices as a protective factor (OR = 0.06) and manure application (OR = 52.2) and state (OR = 108.1) as risk factors. In cross-validation, the model showed a solid predictive performance, with an area under the receiver operating characteristic (ROC) curve of 81%. Overall, the findings highlighted the utility of NRI precipitation data in predicting contamination and demonstrated that farm management, environment, and weather factors should be considered jointly in development of good agricultural practices and measures to reduce produce contamination. PMID:24509926

  14. Fluoroscopy-Guided Sacroiliac Joint Injection: Description of a Modified Technique.

    PubMed

    Kasliwal, Prasad Jaychand; Kasliwal, Sapana

    2016-02-01

    Sacroiliac joint (SIJ) pathology is a common etiologic cause for 10 - 27% of cases of mechanical low back pain (LBP) below the L5 level. In the absence of definite clinical or radiologic diagnostic criteria, controlled blocks of the SIJ have become the choice assessment method for making the diagnosis of SIJ pain. The SI joint is most often characterized as a large, auricular-shaped, diarthrodial synovial joint. In reality, its synovial characteristic is limited only to the distal third and anterior third. In SIJ interventions, the lateral view has been underutilized. In our technique, we used the lateral view to create a three-dimensional view of the SIJ to aid in gauging the accurateness of the contrast spread and to obtain a precise block. After obtaining appropriate fluoroscopic images, a curved tip spinal needle was directed into the inferior aspect of the SIJ using a posterior approach. As the needle contacts firm tissues on the posterior aspect of the joint, position of the needle tip is checked using lateral fluoroscopy. In the lateral view, the needle tip position is manipulated to keep it in the anterior third of the SIJ and contrast is injected. Our criteria for accurate SIJ block, in posteroanterior (PA) view, is the injection of the contrast medium should outline the joint space and the contrast medium should be seen to travel cephalad along the joint line. In the lateral view, the contrast medium most densely outlines the parameter of the joint. We have utilized this method with good effect in approximately 30 cases over one year. Out of 30 cases, needle position and contrast spread was satisfactory in 28 and 27 cases, respectively. So satisfactory needle placement and contrast spread was in 93% and 87% cases. Pain relief of 80% or more after intra-articular injection of local anesthetic was seen in 50% (15 of 30) patients; pain relief of 50 - 79% was witnessed in 30% (9 of 30) patients. Thus, pain decreased 50% or more in 80% (24 of 30) of the joints

  15. Clinical and Radiographic Results of Indirect Decompression and Posterior Cervical Fusion for Single-Level Cervical Radiculopathy Using an Expandable Implant with 2-Year Follow-Up.

    PubMed

    Siemionow, Kris; Janusz, Piotr; Phillips, Frank M; Youssef, Jim A; Isaacs, Robert; Tyrakowski, Marcin; McCormack, Bruce

    2016-11-01

    Background  Indirect posterior cervical nerve root decompression and fusion performed by placing bilateral posterior cervical cages in the facet joints from a posterior approach has been proposed as an option to treat select patients with cervical radiculopathy. The purpose of this study was to report 2-year clinical and radiologic results of this treatment method. Methods  Patients who failed nonsurgical management for single-level cervical radiculopathy were recruited. Surgical treatment involved a posterior approach with decortication of the lateral mass and facet joint at the treated level followed by placement of the DTRAX Expandable Cage (Providence Medical Technology, Lafayette, California, United States) into both facet joints. Iliac crest bone autograft was mixed with demineralized bone matrix and used in all cases. The Neck Disability Index (NDI), visual analog scale (VAS) for neck and arm pain, and SF-12 v.2 questionnaire were evaluated preoperatively and 2 years postoperatively. Segmental (treated level) and overall C2-C7 cervical lordosis, disk height, adjacent segment degeneration, and fusion were assessed on computed tomography scans and radiographs acquired preoperatively and 2 years postoperatively. Results  Overall, 53 of 60 enrolled patients were available at 2-year follow-up. There were 35 females and 18 males with a mean age of 53 years (range: 40-75 years). The operated level was C3-C4 ( N  = 3), C4-C5 ( N  = 6), C5-C6 ( N  = 36), and C6-C7 ( N  = 8). The mean preoperative and 2-year scores were NDI: 32.3 versus 9.1 ( p  < 0.0001); VAS Neck Pain: 7.4 versus 2.6 ( p  < 0.0001); VAS Arm Pain: 7.4 versus 2.6 ( p  < 0.0001); SF-12 Physical Component Summary: 34.6 versus 43.6 ( p  < 0.0001), and SF-12 Mental Component Summary: 40.8 versus 51.4 ( p  < 0.0001). No significant changes in overall or segmental lordosis were noted after surgery. Radiographic fusion rate was 98.1%. There was no device failure

  16. Clinical Evaluation of the Root Tear of the Posterior Horn of the Medial Meniscus in Total Knee Arthroplasty for Osteoarthritis.

    PubMed

    Choi, Eui-Sung; Park, Sang-Jun

    2015-06-01

    To investigate the incidence of root tears of the posterior horn of the medial meniscus in total knee replacement arthroplasty for knee osteoarthritis and retrospectively analyze clinical results and factors associated with root tears. There were 197 knees of 140 enrolled patients who had undergone total knee replacement arthroplasty between September 2010 and May 2014. The presence of a root tear of the posterior horn of the medial meniscus was confirmed in all patients. Statistical analysis was performed to investigate the correlation between root tears and the possible factors of meniscal tears including gender, age, severity of symptoms (visual analogue scale [VAS] score and medial joint line tenderness), grade of osteoarthritis (Kellgren-Lawrence grading scale), body mass index (BMI), varus deformity, and mechanical axis deviation. Meniscal tears were observed in 154 knees (78.17%). The root tear had correlation with the severity of osteoarthritis (p<0.05), varus deformity (p<0.05), mechanical axis deviation (p<0.05), and BMI (p<0.05). Factors considered to represent the severity of osteoarthritis were found to be associated with root tears of the medial meniscus posterior horn. Increased BMI seemed to be associated with the increased incidence of root tears of the medial meniscus posterior horn.

  17. Clinical Evaluation of the Root Tear of the Posterior Horn of the Medial Meniscus in Total Knee Arthroplasty for Osteoarthritis

    PubMed Central

    Park, Sang-Jun

    2015-01-01

    Purpose To investigate the incidence of root tears of the posterior horn of the medial meniscus in total knee replacement arthroplasty for knee osteoarthritis and retrospectively analyze clinical results and factors associated with root tears. Materials and Methods There were 197 knees of 140 enrolled patients who had undergone total knee replacement arthroplasty between September 2010 and May 2014. The presence of a root tear of the posterior horn of the medial meniscus was confirmed in all patients. Statistical analysis was performed to investigate the correlation between root tears and the possible factors of meniscal tears including gender, age, severity of symptoms (visual analogue scale [VAS] score and medial joint line tenderness), grade of osteoarthritis (Kellgren-Lawrence grading scale), body mass index (BMI), varus deformity, and mechanical axis deviation. Results Meniscal tears were observed in 154 knees (78.17%). The root tear had correlation with the severity of osteoarthritis (p<0.05), varus deformity (p<0.05), mechanical axis deviation (p<0.05), and BMI (p<0.05). Conclusions Factors considered to represent the severity of osteoarthritis were found to be associated with root tears of the medial meniscus posterior horn. Increased BMI seemed to be associated with the increased incidence of root tears of the medial meniscus posterior horn. PMID:26060607

  18. Delayed Single Stage Perineal Posterior Urethroplasty.

    PubMed

    Ali, Shahzad; Shahnawaz; Shahzad, Iqbal; Baloch, Muhammad Umar

    2015-06-01

    To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Descriptive case series. Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patient's age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3%) experienced recurrent stricture during first 10 months. Five (16.6%) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6%) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3% with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures.

  19. Application of multivariate Gaussian detection theory to known non-Gaussian probability density functions

    NASA Astrophysics Data System (ADS)

    Schwartz, Craig R.; Thelen, Brian J.; Kenton, Arthur C.

    1995-06-01

    A statistical parametric multispectral sensor performance model was developed by ERIM to support mine field detection studies, multispectral sensor design/performance trade-off studies, and target detection algorithm development. The model assumes target detection algorithms and their performance models which are based on data assumed to obey multivariate Gaussian probability distribution functions (PDFs). The applicability of these algorithms and performance models can be generalized to data having non-Gaussian PDFs through the use of transforms which convert non-Gaussian data to Gaussian (or near-Gaussian) data. An example of one such transform is the Box-Cox power law transform. In practice, such a transform can be applied to non-Gaussian data prior to the introduction of a detection algorithm that is formally based on the assumption of multivariate Gaussian data. This paper presents an extension of these techniques to the case where the joint multivariate probability density function of the non-Gaussian input data is known, and where the joint estimate of the multivariate Gaussian statistics, under the Box-Cox transform, is desired. The jointly estimated multivariate Gaussian statistics can then be used to predict the performance of a target detection algorithm which has an associated Gaussian performance model.

  20. Anticipating abrupt shifts in temporal evolution of probability of eruption

    NASA Astrophysics Data System (ADS)

    Rohmer, J.; Loschetter, A.

    2016-04-01

    Estimating the probability of eruption by jointly accounting for different sources of monitoring parameters over time is a key component for volcano risk management. In the present study, we are interested in the transition from a state of low-to-moderate probability value to a state of high probability value. By using the data of MESIMEX exercise at the Vesuvius volcano, we investigated the potential for time-varying indicators related to the correlation structure or to the variability of the probability time series for detecting in advance this critical transition. We found that changes in the power spectra and in the standard deviation estimated over a rolling time window both present an abrupt increase, which marks the approaching shift. Our numerical experiments revealed that the transition from an eruption probability of 10-15% to > 70% could be identified up to 1-3 h in advance. This additional lead time could be useful to place different key services (e.g., emergency services for vulnerable groups, commandeering additional transportation means, etc.) on a higher level of alert before the actual call for evacuation.

  1. Evaluation of Water Content in Lumbar Intervertebral Discs and Facet Joints Before and After Physiological Loading Using T2 Mapping MRI.

    PubMed

    Yamabe, Daisuke; Murakami, Hideki; Chokan, Kou; Endo, Hirooki; Oikawa, Ryosuke; Sawamura, Shoitsu; Doita, Minoru

    2017-12-15

    T2 mapping was used to quantify the water content of lumbar spine intervertebral discs (IVDs) and facet joints before and after physiological loading. The aim of this study was to clarify the interaction between lumbar spine IVD and facet joints as load-bearing structures by measuring the water content of their matrix after physiological loading using T2 mapping magnetic resonance imaging (MRI). To date, few reports have functionally evaluated lumbar spine IVD and facet joints, and their interaction in vivo. T2 mapping may help detect changes in the water content of IVD and articular cartilage of facet joints before and after physiological loading, thereby enabling the evaluation of changes in interacted water retention between IVD and facet joints. Twenty asymptomatic volunteers (10 female and 10 male volunteers; mean age, 19.3 years; age range, 19-20 years) underwent MRI before and after physiological loading such as lumbar flexion, extension, and rotation. Each IVD from L1/2 to L5/S1 was sliced at center of the disc space, and the T2 value was measured at the nucleus pulposus (NP), anterior annulus fibrosus (AF), posterior AF, and bilateral facet joints. In the NP, T2 values significantly decreased after exercise at every lumbar spinal level. In the anterior AF, there were no significant differences in T2 values at any level. In the posterior AF, T2 values significantly increased only at L4/5. In the bilateral facet joints, T2 values significantly decreased after exercise at every level. There was a significant decrease in the water content of facet joints and the NP at every lumbar spinal level after dynamic loading by physical lumbar exercise. These changes appear to play an important and interactional role in the maintenance of the interstitial matrix in the IVD NP and cartilage in the facet joint. 3.

  2. Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics.

    PubMed

    Imai, T; Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

    2014-01-01

    The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture.

  3. One-stage posterior approaches for treatment of thoracic spinal infection: Transforaminal and costotransversectomy, compared with anterior approach with posterior instrumentation.

    PubMed

    Kao, Fu-Cheng; Tsai, Tsung-Ting; Niu, Chi-Chien; Lai, Po-Liang; Chen, Lih-Huei; Chen, Wen-Jer

    2017-10-01

    Treating thoracic infective spondylodiscitis with anterior surgical approaches carry a relatively high risk of perioperative and postoperative complications. Posterior approaches have been reported to result in lower complication rates than anterior procedures, but more evidence is needed to demonstrate the safety and efficacy of 1-stage posterior approaches for treating infectious thoracic spondylodiscitis.Preoperative and postoperative clinical data, of 18 patients who underwent 2 types of 1-stage posterior procedures, costotransversectomy and transforaminal thoracic interbody debridement and fusion and 7 patients who underwent anterior debridement and reconstruction with posterior instrumentation, were retrospectively assessed.The clinical outcomes of patients treated with 1-stage posterior approaches were generally good, with good infection control, back pain relief, kyphotic angle correction, and either partial or solid union for fusion status. Furthermore, they achieved shorter surgical time, fewer postoperative complications, and shorter hospital stay than the patients underwent anterior debridement with posterior instrumentation.The results suggested that treating thoracic spondylodiscitis with a single-stage posterior approach might prevent postoperative complications and avoid respiratory problems associated with anterior approaches. Single-stage posterior approaches would be recommended for thoracic spine infection, especially for patients with medical comorbidities.

  4. HABITAT ASSESSMENT USING A RANDOM PROBABILITY BASED SAMPLING DESIGN: ESCAMBIA RIVER DELTA, FLORIDA

    EPA Science Inventory

    Smith, Lisa M., Darrin D. Dantin and Steve Jordan. In press. Habitat Assessment Using a Random Probability Based Sampling Design: Escambia River Delta, Florida (Abstract). To be presented at the SWS/GERS Fall Joint Society Meeting: Communication and Collaboration: Coastal Systems...

  5. Three-dimensional reconstruction of rat knee joint using episcopic fluorescence image capture.

    PubMed

    Takaishi, R; Aoyama, T; Zhang, X; Higuchi, S; Yamada, S; Takakuwa, T

    2014-10-01

    Development of the knee joint was morphologically investigated, and the process of cavitation was analyzed by using episcopic fluorescence image capture (EFIC) to create spatial and temporal three-dimensional (3D) reconstructions. Knee joints of Wister rat embryos between embryonic day (E)14 and E20 were investigated. Samples were sectioned and visualized using an EFIC. Then, two-dimensional image stacks were reconstructed using OsiriX software, and 3D reconstructions were generated using Amira software. Cavitations of the knee joint were constructed from five divided portions. Cavity formation initiated at multiple sites at E17; among them, the femoropatellar cavity (FPC) was the first. Cavitations of the medial side preceded those of the lateral side. Each cavity connected at E20 when cavitations around the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were completed. Cavity formation initiated from six portions. In each portion, development proceeded asymmetrically. These results concerning anatomical development of the knee joint using EFIC contribute to a better understanding of the structural feature of the knee joint. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  6. Bayesian Retrieval of Complete Posterior PDFs of Oceanic Rain Rate From Microwave Observations

    NASA Technical Reports Server (NTRS)

    Chiu, J. Christine; Petty, Grant W.

    2005-01-01

    This paper presents a new Bayesian algorithm for retrieving surface rain rate from Tropical Rainfall Measurements Mission (TRMM) Microwave Imager (TMI) over the ocean, along with validations against estimates from the TRMM Precipitation Radar (PR). The Bayesian approach offers a rigorous basis for optimally combining multichannel observations with prior knowledge. While other rain rate algorithms have been published that are based at least partly on Bayesian reasoning, this is believed to be the first self-contained algorithm that fully exploits Bayes Theorem to yield not just a single rain rate, but rather a continuous posterior probability distribution of rain rate. To advance our understanding of theoretical benefits of the Bayesian approach, we have conducted sensitivity analyses based on two synthetic datasets for which the true conditional and prior distribution are known. Results demonstrate that even when the prior and conditional likelihoods are specified perfectly, biased retrievals may occur at high rain rates. This bias is not the result of a defect of the Bayesian formalism but rather represents the expected outcome when the physical constraint imposed by the radiometric observations is weak, due to saturation effects. It is also suggested that the choice of the estimators and the prior information are both crucial to the retrieval. In addition, the performance of our Bayesian algorithm is found to be comparable to that of other benchmark algorithms in real-world applications, while having the additional advantage of providing a complete continuous posterior probability distribution of surface rain rate.

  7. Extensile posterior approach to the ankle with detachment of the achilles tendon for oncologic indications.

    PubMed

    Maheshwari, Aditya V; Walters, Jason A; Henshaw, Robert M

    2012-05-01

    We describe an extensile posterior approach to the ankle with detachment of the Achilles tendon for resection of extensive tumors involving the posterior ankle. To the best of our knowledge, this approach and its results have not been reported for oncologic indications. The surgical technique involved detachment of the Achilles tendon, tumor resection and reconstruction of the Achilles tendon with anchor sutures, and was used in six patients. The diagnosis was pigmented villonodular synovitis (5) and chondroblastoma (1). At a mean of 6 (range, 2 to 10) years followup, all patients were free from tumor. All patients could walk an unlimited amount without any support. There were no problems with Achilles incompetence. The mean Musculoskeletal Tumor Society score was 97 ± 4.2% (range, 90 to 100) and the mean Achilles Tendon Total Rupture Score was 95 ± 5.7 (range, 87 to 100). One patient with screwed suture anchors had backing out of two anchors along with deep infection, requiring surgical debridement and anchor removal. One other patient had a post-traumatic small wound dehiscence which responded to local wound care. Excellent exposure, tumor control and patient function were achieved by this approach in a select group of patients. The surgical technique described in this report offers another alternative for an extensile posterior approach to the ankle and/or subtalar joints.

  8. Atlantoaxial manual realignment in a patient with traumatic atlantoaxial joint disruption.

    PubMed

    Goel, Atul; Figueiredo, Antonio; Maheshwari, Shradha; Shah, Abhidha

    2010-05-01

    We report a patient with complex traumatic translatory atlantoaxial dislocation, who we treated by joint exposure and reduction of the dislocation by facet manipulation and subsequent plate and screw atlantoaxial fixation. A 28-year-old male had fallen 7.6m (25 feet), and following the fall had severe neck pain but no neurological deficit. Investigations revealed a fracture at the base of the odontoid process and posterior displacement of the entire atlas over the axis, resulting in a translatory atlantoaxial dislocation. Head traction failed as he developed severe vertigo following its application. The patient was operated upon in a prone position. We opened the atlantoaxial joint and realigned the facets using distraction and manipulation techniques and secured the joint using a plate and screw interarticular method. The patient tolerated the treatment well and was symptom-free after 28 months. Postoperative images showed good craniovertebral alignment. Although technically challenging, direct manipulation of the facets of the atlas and axis can result in excellent craniovertebral realignment.

  9. Biomechanical consequences of a nonanatomic posterior medial meniscal root repair.

    PubMed

    LaPrade, Christopher M; Foad, Abdullah; Smith, Sean D; Turnbull, Travis Lee; Dornan, Grant J; Engebretsen, Lars; Wijdicks, Coen A; LaPrade, Robert F

    2015-04-01

    Posterior medial meniscal root tears have been reported to extrude with the meniscus becoming adhered posteromedially along the posterior capsule. While anatomic repair has been reported to restore tibiofemoral contact mechanics, it is unknown whether nonanatomic positioning of a meniscal root repair to a posteromedial location would restore the loading profile of the knee joint. The purpose of this study was to compare the tibiofemoral contact mechanics of a nonanatomic posterior medial meniscal tear with that of the intact knee or anatomic repair. It was hypothesized that a nonanatomic root repair would not restore the tibiofemoral contact pressures and areas to that of the intact or anatomic repair state. Controlled laboratory study. Tibiofemoral contact mechanics were recorded in 6 male human cadaveric knee specimens (average age, 45.8 years) using pressure sensors. Each knee underwent 5 testing conditions for the posterior medial meniscal root: (1) intact knee; (2) root tear; (3) anatomic transtibial pull-out repair; (4) nonanatomic transtibial pull-out repair, placed 5 mm posteromedially along the edge of the articular cartilage; and (5) root tear concomitant with an ACL tear. Knees were loaded with a 1000-N axial compressive force at 4 flexion angles (0°, 30°, 60°, 90°), and contact area, mean contact pressure, and peak contact pressure were calculated. Contact area was significantly lower after nonanatomic repair than for the intact knee at all flexion angles (mean = 44% reduction) and significantly higher for anatomic versus nonanatomic repair at all flexion angles (mean = 27% increase). At 0° and 90°, and when averaged across flexion angles, the nonanatomic repair significantly increased mean contact pressures in comparison to the intact knee or anatomic repair. When averaged across flexion angles, the peak contact pressures after nonanatomic repair were significantly higher than the intact knee but not the anatomic repair. In contrast, when

  10. The Effects of Generalized Joint Laxity on Risk of Anterior Cruciate Ligament Injury in Young Female Athletes

    PubMed Central

    Myer, Gregory D.; Ford, Kevin R.; Paterno, Mark V.; Nick, Todd G.; Hewett, Timothy E.

    2012-01-01

    Background Women who participate in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than men. Purpose To prospectively determine if female athletes with decreased passive knee joint restraint (greater joint laxity) and greater side-to-side differences in knee laxity would be at increased risk of anterior cruciate ligament injury. Study Design Case control study; Level of evidence, 3. Methods From 1558 female soccer and basketball players who were prospectively screened, 19 went on to tear their anterior cruciate ligaments. Four height- and mass-matched control subjects were selected from the uninjured screened athletes for comparison with each of the 19 injured subjects, making a total of 95 subjects (19 injured; 76 uninjured). Generalized joint-laxity tests and anterior-posterior tibiofemoral translation were quantified using the CompuKT knee arthrometer. A multivariable logistic regression model was constructed to determine predictors of anterior cruciate ligament injury status from recorded laxity measures. Results A multivariable logistic regression model (chi-square = 18.6; P = .002) used the independent variables laxity measures of knee hyperextension (P = .02), wrist and thumb to forearm opposition (P = .80), fifth-finger hyperextension >90° (P = .71), side-to-side differences in anterior-posterior tibiofemoral translation (P = .002), and prior knee injury (P = .22) to predict anterior cruciate ligament–injury status. The validated C statistic, or validated area under the receiver operating characteristic curve, was 0.72. For every 1.3-mm increase in side-to-side differences in anterior-posterior knee displacement, the odds of anterior cruciate ligament–injured status increased 4-fold (95% confidence interval, 1.68–9.69). A positive measure of knee hyperextension increased the odds of anterior cruciate ligament–injured status 5-fold (95% confidence interval, 1.24–18.44). Conclusion The current results

  11. Probabilistic Inference: Task Dependency and Individual Differences of Probability Weighting Revealed by Hierarchical Bayesian Modeling

    PubMed Central

    Boos, Moritz; Seer, Caroline; Lange, Florian; Kopp, Bruno

    2016-01-01

    Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modeling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities) by two (likelihoods) design. Five computational models of cognitive processes were compared with the observed behavior. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted) S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model's success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modeling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modeling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision. PMID:27303323

  12. Bayesian Estimation of the DINA Model with Gibbs Sampling

    ERIC Educational Resources Information Center

    Culpepper, Steven Andrew

    2015-01-01

    A Bayesian model formulation of the deterministic inputs, noisy "and" gate (DINA) model is presented. Gibbs sampling is employed to simulate from the joint posterior distribution of item guessing and slipping parameters, subject attribute parameters, and latent class probabilities. The procedure extends concepts in Béguin and Glas,…

  13. Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics

    PubMed Central

    Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

    2014-01-01

    Objectives: The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. Methods: A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. Results: 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. Conclusions: Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture. PMID:24336313

  14. Traumatic lesions of the posterior urethra.

    PubMed

    Velarde-Ramos, L; Gómez-Illanes, R; Campos-Juanatey, F; Portillo-Martín, J A

    2016-11-01

    The posterior urethral lesions are associated with pelvis fractures in 5-10% of cases. The posterior urethra is attached to the pelvis bone by puboprostatic ligaments and the perineal membrane, which explains why disruption of the pelvic ring can injure the urethra at this level. To identify suspected cases of posterior urethral trauma and to perform the diagnosis and its immediate or deferred management. Search in PubMed of articles related to traumatic posterior urethral lesions, written in English or Spanish. We reviewed the relevant publications including literature reviews and chapters from books related to the topic. With patients with pelvis fractures, we must always rule out posterior urethral lesions. The diagnostic examination of choice is retrograde urethrography, which, along with the severity of the condition, will determine the management in the acute phase and whether the treatment will be performed immediately or deferred. Early diagnosis and proper acute management decrease the associated complications, such as strictures, urinary incontinence and erectile dysfunction. Despite the classical association between posterior urethral lesions and pelvic fractures, the management of those lesions (whether immediate or deferred) remains controversial. Thanks to the growing interest in urethral disease, there are an increasing number of studies that help us achieve better management of these lesions. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Short-Term Results of Total Knee Arthroplasty with Anterior-Posterior Glide LCS Mobile-Bearing System

    PubMed Central

    Kim, Kyung Taek; Kang, Min Soo; Lim, Young Hoon; Park, Jin Woo

    2014-01-01

    Purpose To evaluate the clinical and radiological results of total knee arthroplasty (TKA) using the anterior-posterior glide (APG) low contact stress (LCS) mobile-bearing system. Materials and Methods We evaluated 130 knees in 117 patients who had undergone TKA with APG LCS mobile-bearing system between September 2005 and July 2007 and could be followed over 5 years. The mean follow-up period was 68 months. The clinical and radiological results were evaluated using the American Knee Society Scoring System, Oxford knee score and the American Knee Society Roentgenographic Evaluation and Scoring System. And we analyzed short-term postoperative complications. Results The average range of motion of the knee joint was 107.9° (range, 70° to 135°) preoperatively and 125.2° (range, 90° to 135°) at the last follow-up. The average knee and functional scores were improved from 39.1 and 42.0 to 71.2 and 75.6, respectively, between the preoperative and last follow-up evaluation. The Oxford knee score was decreased from 42.9 preoperatively to 23.1 at the last follow-up. The femoro-tibial angle (anatomical axis) changed from 10.1° varus preoperatively to 3.3° valgus at the last follow-up. Radiolucency was observed in 14% of all cases. There were 1 case of traumatic dislocation of the polyethylene liner, 1 case of aseptic loosening and 6 cases of posterior instability because of posterior cruciate ligament (PCL) insufficiency. Conclusions TKA with APG LCS mobile-bearing system demonstrated relatively good short-term clinical and radiological results. However, further considerations for posterior instability associated with PCL insufficiency are needed. PMID:25229046

  16. Arthroscopic Management of Scaphoid-Trapezium-Trapezoid Joint Arthritis.

    PubMed

    Pegoli, Loris; Pozzi, Alessandro

    2017-11-01

    Scaphoid-trapezium-trapezoid (STT) joint arthritis is a common condition consisting of pain on the radial side of the wrist and base of the thumb, swelling, and tenderness over the STT joint. Common symptoms are loss of grip strength and thumb function. There are several treatments, from symptomatic conservative treatment to surgical solutions, such as arthrodesis, arthroplasties, and prosthesis implant. The role of arthroscopy has grown and is probably the best treatment of this condition. Advantages of arthroscopic management of STT arthritis are faster recovery, better view of the joint during surgery, and possibility of creating less damage to the capsular and ligamentous structures. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Imaging of the Posterior Skull Base.

    PubMed

    Job, Joici; Branstetter, Barton F

    2017-01-01

    The posterior skull base can be involved by a variety of pathologic processes. They can be broadly classified as: traumatic, neoplastic, vascular, and inflammatory. Pathology in the posterior skull base usually involves the lower cranial nerves, either as a source of pathology or a secondary source of symptoms. This review will categorize pathology arising in the posterior skull base and describe how it affects the skull base itself and surrounding structures. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Maximum aposteriori joint source/channel coding

    NASA Technical Reports Server (NTRS)

    Sayood, Khalid; Gibson, Jerry D.

    1991-01-01

    A maximum aposteriori probability (MAP) approach to joint source/channel coder design is presented in this paper. This method attempts to explore a technique for designing joint source/channel codes, rather than ways of distributing bits between source coders and channel coders. For a nonideal source coder, MAP arguments are used to design a decoder which takes advantage of redundancy in the source coder output to perform error correction. Once the decoder is obtained, it is analyzed with the purpose of obtaining 'desirable properties' of the channel input sequence for improving overall system performance. Finally, an encoder design which incorporates these properties is proposed.

  19. [Occiput posterior presentation at delivery: Materno-foetal outcomes and predictive factors of rotation].

    PubMed

    Othenin-Girard, V; Boulvain, M; Guittier, M-J

    2018-02-01

    To describe the maternal and foetal outcomes of an occiput posterior foetal position at delivery; to evaluate predictive factors of anterior rotation during labour. Descriptive retrospective analysis of a cohort of 439 women with foetuses in occiput posterior position during labour. Logistic regression analysis to quantify the effect of factors that may favour anterior rotation. Most of foetuses (64%) do an anterior rotation during labour and 13% during the expulsive phase. The consequences of a persistent foetal occiput posterior position during delivery are a significantly increased average time of second stage labour compared to others positions (65.19minutes vs. 43.29, P=0.001, respectively); a higher percentage of caesarean sections (72.0% versus 4.7%, P<0.001) and instrumental delivery (among low-birth deliveries, 60.7% versus 25.2%, P<0.001); more frequent third-degree perineal tears (14.3% vs. 0.6%, P<0.001) and more abundant blood loss (560mL versus 344mL, P<0.001). In a multi-variable model including nulliparity, station of the presenting part and degree of flexion of the foetal head at complete dilatation, the only predictive factor independent of rotation at delivery is a good flexion of the foetal head at complete dilatation, which multiplies the anterior rotation probability by six. A good flexion of the foetal head is significantly associated with anterior rotation. Other studies exploring ways to increase anterior rotation during labour are needed to reduce the very high risk of caesarean section and instrumentation associated with the foetal occiput posterior position. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Multi-joint postural behavior in patients with knee osteoarthritis.

    PubMed

    Turcot, Katia; Sagawa, Yoshimasa; Hoffmeyer, Pierre; Suvà, Domizio; Armand, Stéphane

    2015-12-01

    Previous studies have demonstrated balance impairment in patients with knee osteoarthritis (OA). Although it is currently accepted that postural control depends on multi-joint coordination, no study has previously considered this postural strategy in patients suffering from knee OA. The objectives of this study were to investigate the multi-joint postural behavior in patients with knee OA and to evaluate the association with clinical outcomes. Eighty-seven patients with knee OA and twenty-five healthy elderly were recruited to the study. A motion analysis system and two force plates were used to investigate the joint kinematics (trunk and lower body segments), the lower body joint moments, the vertical ground reaction force ratio and the center of pressure (COP) during a quiet standing task. Pain, functional capacity and quality of life status were also recorded. Patients with symptomatic and severe knee OA adopt a more flexed posture at all joint levels in comparison with the control group. A significant difference in the mean ratio was found between groups, showing an asymmetric weight distribution in patients with knee OA. A significant decrease in the COP range in the anterior-posterior direction was also observed in the group of patients. Only small associations were observed between postural impairments and clinical outcomes. This study brings new insights regarding the postural behavior of patients with severe knee OA during a quiet standing task. The results confirm the multi-joint asymmetric posture adopted by this population. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Cross-sectional and Longitudinal Associations between Knee Joint Effusion Synovitis and Knee Pain in Older Adults.

    PubMed

    Wang, Xia; Jin, Xingzhong; Han, Weiyu; Cao, Yuelong; Halliday, Andrew; Blizzard, Leigh; Pan, Faming; Antony, Benny; Cicuttini, Flavia; Jones, Graeme; Ding, Changhai

    2016-01-01

    To describe the cross-sectional and longitudinal associations between knee regional effusion synovitis and knee pain in older adults. Data from a population-based random sample (n = 880, mean age 62 yrs, 50% women) were used. Baseline knee joint effusion synovitis was graded (0-3) using T2-weighted magnetic resonance imaging (MRI) in the suprapatellar pouch, central portion, posterior femoral recess, and subpopliteal recess. Effusion synovitis of the whole joint was defined as a score of ≥ 2 in any subregion. Other knee structural (including cartilage, bone marrow, and menisci) lesions were assessed by MRI at baseline. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire at baseline and 2.6 years later. Multivariable analyses were performed after adjustment for age, sex, body mass index, and other structural lesions. The prevalence of effusion synovitis was 67%. Suprapatellar pouch effusion synovitis was significantly and independently associated with increased total and nonweight-bearing knee pain in both cross-sectional and longitudinal analyses (for an increase in total knee pain of ≥ 5, RR 1.26 per grade, 95% CI 1.04-1.52), and increased weight-bearing knee pain in longitudinal analysis only. Effusion synovitis in posterior femoral recess and central portion were independently associated with increases in nonweight-bearing pain (RR 1.63 per grade, 95% CI 1.32-2.01 and RR 1.29 per grade, 95% CI 1.01-1.65, respectively) in longitudinal analyses only. Knee joint effusion synovitis has independent associations with knee pain in older adults. Suprapatellar pouch effusion synovitis is associated with nonweight-bearing and weight-bearing knee pain, while posterior femoral recess and central portion effusion synovitis are only associated with nonweight-bearing pain.

  2. Comparative Analysis of Combined (First Anterior, Then Posterior) Versus Only Posterior Approach for Treating Severe Scoliosis

    PubMed Central

    Hero, Nikša; Vengust, Rok; Topolovec, Matevž

    2017-01-01

    Study Design. A retrospective, one center, institutional review board approved study. Objective. Two methods of operative treatments were compared in order to evaluate whether a two-stage approach is justified for correction of bigger idiopathic scoliosis curves. Two stage surgery, combined anterior approach in first operation and posterior instrumentation and correction in the second operation. One stage surgery included only posterior instrumentation and correction. Summary of Background Data. Studies comparing two-stage approach and only posterior approach are rather scarce, with shorter follow up and lack of clinical data. Methods. Three hundred forty eight patients with idiopathic scoliosis were operated using Cotrel–Dubousset (CD) hybrid instrumentation with pedicle screw and hooks. Only patients with curvatures more than or equal to 61° were analyzed and divided in two groups: two stage surgery (N = 30) and one stage surgery (N = 46). The radiographic parameters as well as duration of operation, hospitalization time, and number of segments included in fusion and clinical outcome were analyzed. Results. No statistically significant difference was observed in correction between two-stage group (average correction 69%) and only posterior approach group (average correction 66%). However, there were statistically significant differences regarding hospitalization time, duration of the surgery, and the number of instrumented segments. Conclusion. Two-stage surgery has only a limited advantage in terms of postoperative correction angle compared with the posterior approach. Posterior instrumentation and correction is satisfactory, especially taking into account that the patient is subjected to only one surgery. Level of Evidence: 3 PMID:28125525

  3. Hip and knee joint loading during vertical jumping and push jerking

    PubMed Central

    Cleather, Daniel J; Goodwin, Jon E; Bull, Anthony MJ

    2014-01-01

    Background The internal joint contact forces experienced at the lower limb have been frequently studied in activities of daily living and rehabilitation activities. In contrast, the forces experienced during more dynamic activities are not well understood, and those studies that do exist suggest very high degrees of joint loading. Methods In this study a biomechanical model of the right lower limb was used to calculate the internal joint forces experienced by the lower limb during vertical jumping, landing and push jerking (an explosive exercise derived from the sport of Olympic weightlifting), with a particular emphasis on the forces experienced by the knee. Findings The knee experienced mean peak loadings of 2.4-4.6 × body weight at the patellofemoral joint, 6.9-9.0 × body weight at the tibiofemoral joint, 0.3-1.4 × body weight anterior tibial shear and 1.0-3.1 × body weight posterior tibial shear. The hip experienced a mean peak loading of 5.5-8.4 × body weight and the ankle 8.9-10.0 × body weight. Interpretation The magnitudes of the total (resultant) joint contact forces at the patellofemoral joint, tibiofemoral joint and hip are greater than those reported in activities of daily living and less dynamic rehabilitation exercises. The information in this study is of importance for medical professionals, coaches and biomedical researchers in improving the understanding of acute and chronic injuries, understanding the performance of prosthetic implants and materials, evaluating the appropriateness of jumping and weightlifting for patient populations and informing the training programmes of healthy populations. PMID:23146164

  4. An improved OpenSim gait model with multiple degrees of freedom knee joint and knee ligaments.

    PubMed

    Xu, Hang; Bloswick, Donald; Merryweather, Andrew

    2015-08-01

    Musculoskeletal models are widely used to investigate joint kinematics and predict muscle force during gait. However, the knee is usually simplified as a one degree of freedom joint and knee ligaments are neglected. The aim of this study was to develop an OpenSim gait model with enhanced knee structures. The knee joint in this study included three rotations and three translations. The three knee rotations and mediolateral translation were independent, with proximodistal and anteroposterior translations occurring as a function of knee flexion/extension. Ten elastic elements described the geometrical and mechanical properties of the anterior and posterior cruciate ligaments (ACL and PCL), and the medial and lateral collateral ligaments (MCL and LCL). The three independent knee rotations were evaluated using OpenSim to observe ligament function. The results showed that the anterior and posterior bundles of ACL and PCL (aACL, pACL and aPCL, pPCL) intersected during knee flexion. The aACL and pACL mainly provided force during knee flexion and adduction, respectively. The aPCL was slack throughout the range of three knee rotations; however, the pPCL was utilised for knee abduction and internal rotation. The LCL was employed for knee adduction and rotation, but was slack beyond 20° of knee flexion. The MCL bundles were mainly used during knee adduction and external rotation. All these results suggest that the functions of knee ligaments in this model approximated the behaviour of the physical knee and the enhanced knee structures can improve the ability to investigate knee joint biomechanics during various gait activities.

  5. Posterior Predictive Bayesian Phylogenetic Model Selection

    PubMed Central

    Lewis, Paul O.; Xie, Wangang; Chen, Ming-Hui; Fan, Yu; Kuo, Lynn

    2014-01-01

    We present two distinctly different posterior predictive approaches to Bayesian phylogenetic model selection and illustrate these methods using examples from green algal protein-coding cpDNA sequences and flowering plant rDNA sequences. The Gelfand–Ghosh (GG) approach allows dissection of an overall measure of model fit into components due to posterior predictive variance (GGp) and goodness-of-fit (GGg), which distinguishes this method from the posterior predictive P-value approach. The conditional predictive ordinate (CPO) method provides a site-specific measure of model fit useful for exploratory analyses and can be combined over sites yielding the log pseudomarginal likelihood (LPML) which is useful as an overall measure of model fit. CPO provides a useful cross-validation approach that is computationally efficient, requiring only a sample from the posterior distribution (no additional simulation is required). Both GG and CPO add new perspectives to Bayesian phylogenetic model selection based on the predictive abilities of models and complement the perspective provided by the marginal likelihood (including Bayes Factor comparisons) based solely on the fit of competing models to observed data. [Bayesian; conditional predictive ordinate; CPO; L-measure; LPML; model selection; phylogenetics; posterior predictive.] PMID:24193892

  6. [Atlanto-axial pedicle screw fixation through posterior approach for treatment of atlanto-axial joint instability].

    PubMed

    Zuo, Chun-Guang; Liu, Xia-Jun; Wang, Xin-Hu; Wang, Jian-shun

    2013-01-01

    To discuss the therapeutic effects of the atlantoaxial pedicle screw system fixation in treatment of atlantoaxial instability. From June 2003 to March 2010, 32 patients with atlantoaxial instability were treated by atlantoaxial pedicle screw system fixation, included 21 males and 11 females wiht an average age of 42.5 years old ranging from 28 to 66 years. Among them, 18 cases were odontoid process fractures, 7 were congenital dissociate odontoid process, 4 were Jefferson fracture combined with odontoid fracture, 3 were rheumatic arthritis causing atlantoaxial instability. All patients suffered from the atlantoaxial subluxation and atlantoaxial instability. The JOA score ranged from 4 to 14 (means 9.1 +/- 0.3) before operation. The patients had some image examination including the X-ray of cervical vertebrae (include of dynamic position film), spiral CT 3D reconstruction and/or MRI. The position of pedicle screw system implantation,the angle of pedicle screw system implantation and screw length were measured. Operating skull traction. Operation undewent general anesthesia, implanted the pedicle screw, reduction and bone fusion under direct vision. The bone was fixated between posterior arch of atlas and lamina of axis by the lateral combination bended to posterior. One hundred and twenty-eight atlantoaxial pedicle screws were implanted in 32 patients. No patient had the injure of spinal cord, nerve root and vertebral artery. All patients were followed-up from 6 to 48 months (averaged 16 months). After operation, the JOA score ranged from 11 to 17 (averaged 15.9 +/- 0.2), improvement rate was 86.1%. The fracture of odontoid process were healing completely. All fusion bone were combinated. The internal fixation wasn't loosening and breaking. The atlantoaxial pedicle screw system fixation was effective method to treat atlantoaxial instability. The method had many advantages, such as provide rigid and short segment fixation, safe and simple, high fusion rate. The

  7. Fluoroscopy-Guided Sacroiliac Intraarticular Injection via the Middle Portion of the Joint.

    PubMed

    Kurosawa, Daisuke; Murakami, Eiichi; Aizawa, Toshimi

    2017-09-01

    Sacroiliac intraarticular injection is necessary to confirm sacroiliac joint (SIJ) pain and is usually performed via the caudal one-third portion of the joint. However, this is occasionally impossible for anatomical reasons, and the success rate is low in clinical settings. We describe a technique via the middle portion of the joint. Observational study. Enrolled were 69 consecutive patients (27 men and 42 women, with an average age of 53 years) in whom the middle portion of 100 joints was targeted. With the patient lying prone-oblique with the painful side down, a spinal needle was inserted into the middle portion of the joint. Subsequently, the fluoroscopy tube was angled at a caudal tilt of 25-30° to clearly detect the recess between the ilium and sacrum and the needle depth and direction. When the needle reached the posterior joint line, 2% lidocaine was injected after the contrast medium outlined the joint. The success rate of the injection method was 80% (80/100). Among 80 successful cases, four were previously unsuccessful when the conventional method was used. Intraarticular injection using the new technique was unsuccessful in 20 joints; in three of these cases, the conventional method proved successful, and no techniques were successful in the other 17 cases. The injection technique via the middle portion of the joint can overcome some of the difficulties of the conventional injection method and can improve the chances of successful intraarticular injection. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  8. A new surgical technique for traumatic dislocation of posterior tibial tendon with avulsion fracture of medial malleolus.

    PubMed

    Jeong, Soon-Taek; Hwang, Sun-Chul; Kim, Dong-Hee; Nam, Dae-Cheol

    2015-01-01

    We introduce a case of traumatic dislocation of the posterior tibial tendon with avulsion fracture of the medial malleolus in a 52-year-old female patient who was treated surgically with periosteal flap and suture anchor fixation. Based in the posteromedial ridge of the distal tibia, a quadrilateral periosteal flap was created and folded over the tendon, followed by fixation on the lateral aspect of the groove by use of multiple suture anchors. Clinical and radiological findings 25 months postoperatively showed well-preserved function of the ankle joint with stable tendon gliding.

  9. Immediate combined effect of gastrocnemius stretching and sustained talocrural joint mobilization in individuals with limited ankle dorsiflexion: A randomized controlled trial.

    PubMed

    Kang, Min-Hyeok; Oh, Jae-Seop; Kwon, Oh-Yun; Weon, Jong-Hyuk; An, Duk-Hyun; Yoo, Won-Gyu

    2015-12-01

    Although gastrocnemius stretching and talocrural joint mobilization have been suggested as effective interventions to address limited ankle dorsiflexion passive range of motion (DF PROM), the effects of a combination of the two interventions have not been identified. The aim of the present study was to compare the effects of gastrocnemius stretching combined with joint mobilization and gastrocnemius stretching alone. A randomized controlled trial. In total, 24 individuals with limited ankle DF PROM were randomized to undergo gastrocnemius stretching combined with joint mobilization (12 feet in 12 individuals) or gastrocnemius stretching alone (12 feet in 12 individuals) for 5 min. Ankle kinematics during gait (time to heel-off and ankle DF before heel-off), ankle DF PROM, posterior talar glide, and displacement of the myotendinous junction (MTJ) of the gastrocnemius were assessed before and after the interventions. The groups were compared using two-way repeated measures analysis of variance. Greater increases in the time to heel-off and ankle DF before heel-off during gait and posterior talar glide were observed in the stretching combined with joint mobilization group versus the stretching alone group. Ankle DF PROM and displacement of the MTJ of the gastrocnemius were increased significantly after the interventions in both groups, with no significant difference between them. These findings suggest that gastrocnemius stretching with joint mobilization needs to be considered to improve ankle kinematics during gait. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Posterior polar cataract: A review

    PubMed Central

    Kalantan, Hatem

    2011-01-01

    Posterior polar cataract is a rare form of congenital cataract. It is usually inherited as an autosomal dominant disease, yet it can be sporadic. Five genes have been attributed to the formation of this disease. It is highly associated with complications during surgery, such as posterior capsule rupture and nucleus drop. The reason for this high complication rate is the strong adherence of the opacity to the weak posterior capsule. Different surgical strategies were described for the handling of this challenging entity, most of which emphasized the need for gentle maneuvering in dealing with these cases. It has a unique clinical appearance that should not be missed in order to anticipate, avoid, and minimize the impact of the complications associated with it. PMID:23960967

  11. Facilitating normative judgments of conditional probability: frequency or nested sets?

    PubMed

    Yamagishi, Kimihiko

    2003-01-01

    Recent probability judgment research contrasts two opposing views. Some theorists have emphasized the role of frequency representations in facilitating probabilistic correctness; opponents have noted that visualizing the probabilistic structure of the task sufficiently facilitates normative reasoning. In the current experiment, the following conditional probability task, an isomorph of the "Problem of Three Prisoners" was tested. "A factory manufactures artificial gemstones. Each gemstone has a 1/3 chance of being blurred, a 1/3 chance of being cracked, and a 1/3 chance of being clear. An inspection machine removes all cracked gemstones, and retains all clear gemstones. However, the machine removes 1/2 of the blurred gemstones. What is the chance that a gemstone is blurred after the inspection?" A 2 x 2 design was administered. The first variable was the use of frequency instruction. The second manipulation was the use of a roulette-wheel diagram that illustrated a "nested-sets" relationship between the prior and the posterior probabilities. Results from two experiments showed that frequency alone had modest effects, while the nested-sets instruction achieved a superior facilitation of normative reasoning. The third experiment compared the roulette-wheel diagram to tree diagrams that also showed the nested-sets relationship. The roulette-wheel diagram outperformed the tree diagrams in facilitation of probabilistic reasoning. Implications for understanding the nature of intuitive probability judgments are discussed.

  12. A new posterior iliac puncture/aspiration needle.

    PubMed

    Islam, Anwarul

    2016-03-25

    The needles that are currently used for obtaining bone marrow aspirate samples from the posterior ilium are typically those of 1930s vintage (eg, Klima, Salah or similar needles), which were specifically designed for sternal aspiration. These needles are not designed to obtain bone marrow aspirate samples from the posterior ilium and as a result they are unsatisfactory particularly if the patient is large or obese. A new posterior iliac puncture/aspiration needle has therefore been designed, which is particularly suited for bone marrow aspiration from the posterior ilium. The needle was tested on five cadavers and on five patients. The design and construction of the needle was found to be satisfactory and a marked improvement over the conventional sternal puncture needles particularly when large or obese patients were concerned. The new posterior iliac bone marrow aspiration needle has advantages that overcome the limitations of using a conventional sternal puncture needle to obtain marrow aspirates from the posterior ilium. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  13. A Parallel and Distributed Processing Model of Joint Attention, Social-Cognition and Autism

    PubMed Central

    Mundy, Peter; Sullivan, Lisa; Mastergeorge, Ann M.

    2009-01-01

    Scientific Abstract The impaired development of joint attention is a cardinal feature of autism. Therefore, understanding the nature of joint attention is a central to research on this disorder. Joint attention may be best defined in terms of an information processing system that begins to develop by 4–6 months of age. This system integrates the parallel processing of internal information about one’s own visual attention with external information about the visual attention of other people. This type of joint encoding of information about self and other attention requires the activation of a distributed anterior and posterior cortical attention network. Genetic regulation, in conjunction with self-organizing behavioral activity guides the development of functional connectivity in this network. With practice in infancy the joint processing of self-other attention becomes automatically engaged as an executive function. It can be argued that this executive joint-attention is fundamental to human learning, as well as the development of symbolic thought, social-cognition and social-competence throughout the life span. One advantage of this parallel and distributed processing model of joint attention (PDPM) is that it directly connects theory on social pathology to a range of phenomenon in autism associated with neural connectivity, constructivist and connectionist models of cognitive development, early intervention, activity-dependent gene expression, and atypical ocular motor control. PMID:19358304

  14. Retention of the posterior cruciate ligament versus the posterior stabilized design in total knee arthroplasty: a prospective randomized controlled clinical trial

    PubMed Central

    van den Boom, Lennard GH; Brouwer, Reinoud W; van den Akker-Scheek, Inge; Bulstra, Sjoerd K; van Raaij, Jos JAM

    2009-01-01

    Background Prosthetic design for the use in primary total knee arthroplasty has evolved into designs that preserve the posterior cruciate ligament (PCL) and those in which the ligament is routinely sacrificed (posterior stabilized). In patients with a functional PCL the decision which design is chosen depends largely on the favour and training of the surgeon. The objective of this study is to determine whether the patient's perceived outcome and speed of recovery differs between a posterior cruciate retaining total knee arthroplasty and a posterior stabilized total knee arthroplasty. Methods/Design A randomized controlled trial will be conducted. Patients who are admitted for primary unilateral TKA due to primary osteoarthrosis are included when the following inclusion criteria are met: non-fixed fixed varus or valgus deformity less than 10 degrees, age between 55 and 85 years, body mass index less than 35 kg/m2 and ASA score (American Society of Anaesthesiologists) I or II. Patients are randomized in 2 groups. Patients in the posterior cruciate retaining group will receive a prosthesis with a posterior cut-out for the posterior cruciate ligament and relatively flat topography. In patients allocated to the posterior stabilized group, in which the posterior cruciate ligament is excised, the design may substitute for this function by an intercondylar tibial prominence that articulates with the femur in flexion. Measurements will take place preoperatively and 6 weeks, 3 months, 6 months and 1 year postoperatively. At all measurement points patient's perceived outcome will be assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcome measures are quality of life (SF-36) and physician reported functional status and range of motion as determined with the Knee Society Clinical Rating System (KSS). Discussion In the current practice both posterior cruciate retaining and posterior stabilized designs for total knee

  15. Neural correlates of learning and trajectory planning in the posterior parietal cortex

    PubMed Central

    Torres, Elizabeth B.; Quian Quiroga, Rodrigo; Cui, He; Buneo, Christopher A.

    2013-01-01

    The posterior parietal cortex (PPC) is thought to play an important role in the planning of visually-guided reaching movements. However, the relative roles of the various subdivisions of the PPC in this function are still poorly understood. For example, studies of dorsal area 5 point to a representation of reaches in both extrinsic (endpoint) and intrinsic (joint or muscle) coordinates, as evidenced by partial changes in preferred directions and positional discharge with changes in arm posture. In contrast, recent findings suggest that the adjacent medial intraparietal area (MIP) is involved in more abstract representations, e.g., encoding reach target in visual coordinates. Such a representation is suitable for planning reach trajectories involving shortest distance paths to targets straight ahead. However, it is currently unclear how MIP contributes to the planning of other types of trajectories, including those with various degrees of curvature. Such curved trajectories recruit different joint excursions and might help us address whether their representation in the PPC is purely in extrinsic coordinates or in intrinsic ones as well. Here we investigated the role of the PPC in these processes during an obstacle avoidance task for which the animals had not been explicitly trained. We found that PPC planning activity was predictive of both the spatial and temporal aspects of upcoming trajectories. The same PPC neurons predicted the upcoming trajectory in both endpoint and joint coordinates. The predictive power of these neurons remained stable and accurate despite concomitant motor learning across task conditions. These findings suggest the role of the PPC can be extended from specifying abstract movement goals to expressing these plans as corresponding trajectories in both endpoint and joint coordinates. Thus, the PPC appears to contribute to reach planning and approach-avoidance arm motions at multiple levels of representation. PMID:23730275

  16. Measurement of Posterior Corneal Astigmatism by the IOLMaster 700.

    PubMed

    LaHood, Benjamin R; Goggin, Michael

    2018-05-01

    To provide the first description of posterior corneal astigmatism as measured by the IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany) and assess how its characteristics compare to previous measurements from other devices. A total of 1,098 routine IOLMaster 700 biometric measurements were analyzed to provide magnitudes and orientation of steep and flat axes of anterior and posterior corneal astigmatism. Subgroup analysis was conducted to assess correlation of posterior corneal astigmatism characteristics to anterior corneal astigmatism and describe the distribution of posterior corneal astigmatism with age. Mean posterior corneal astigmatism was 0.24 ± 0.15 diopters (D). The steep axis of posterior corneal astigmatism was vertically oriented in 73.32% of measurements. Correlation between the magnitude of anterior and posterior corneal astigmatism was greatest when the steep axis of the anterior corneal astigmatism was oriented vertically (r = 0.68, P < .0001). Vertical orientation of the steep axis of anterior corneal astigmatism became less common as age increased, whereas for posterior corneal astigmatism it remained by far the most common orientation. This first description of posterior corneal astigmatism measurement by the IOLMaster 700 found the average magnitude of posterior corneal astigmatism and proportion of vertical orientation of steep axis was lower than previous estimates. The IOLMaster 700 appears capable of providing enhanced biometric measurement for individualized surgical planning. [J Refract Surg. 2018;34(5):331-336.]. Copyright 2018, SLACK Incorporated.

  17. Inadvertent trypan blue posterior capsule staining during cataract surgery.

    PubMed

    Burkholder, Bryn M; Srikumaran, Divya; Nanji, Afshan; Lee, Bryan; Weinberg, Robert S

    2013-04-01

    To report 5 cases of inadvertent posterior capsule staining with trypan blue during phacoemulsification. Retrospective, observational case series. Five cases of posterior capsule staining with trypan blue were identified from cataract surgeries performed at an academic institution. All 5 eyes underwent phacoemulsification with use of iris retractors. The surgical videos from each case were reviewed to better understand the mechanisms and risk factors for posterior capsule staining with trypan blue and techniques to avoid this complication. No eyes had clinical evidence of zonular pathology during their preoperative examination. Only 1 patient reported a possible childhood history of trauma to both eyes. One eye had uveitis, requiring posterior synechialysis. All 5 cases involved the use of iris retractors. No other intraoperative complications occurred, and the intraocular lens was successfully placed in the capsular bag in all cases. All eyes had resolution of posterior capsule staining by postoperative day 8. Inadvertent posterior capsule staining with trypan blue can occur in eyes that appear structurally normal. The use of iris retractors may facilitate posterior capsule staining by allowing the posterior flow of trypan blue under the iris and through the zonules to the posterior capsule. Surgeons should consider techniques to minimize the risk of posterior capsule staining, particularly in cases involving the use of iris retractors. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Behavioral effect of knee joint motion on body's center of mass during human quiet standing.

    PubMed

    Yamamoto, Akio; Sasagawa, Shun; Oba, Naoko; Nakazawa, Kimitaka

    2015-01-01

    The balance control mechanism during upright standing has often been investigated using single- or double-link inverted pendulum models, involving the ankle joint only or both the ankle and hip joints, respectively. Several studies, however, have reported that knee joint motion during quiet standing cannot be ignored. This study aimed to investigate the degree to which knee joint motion contributes to the center of mass (COM) kinematics during quiet standing. Eight healthy adults were asked to stand quietly for 30s on a force platform. Angular displacements and accelerations of the ankle, knee, and hip joints were calculated from kinematic data obtained by a motion capture system. We found that the amplitude of the angular acceleration was smallest in the ankle joint and largest in the hip joint (ankle < knee < hip). These angular accelerations were then substituted into three biomechanical models with or without the knee joint to estimate COM acceleration in the anterior-posterior direction. Although the "without-knee" models greatly overestimated the COM acceleration, the COM acceleration estimated by the "with-knee" model was similar to the actual acceleration obtained from force platform measurement. These results indicate substantial effects of knee joint motion on the COM kinematics during quiet standing. We suggest that investigations based on the multi-joint model, including the knee joint, are required to reveal the physiologically plausible balance control mechanism implemented by the central nervous system. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Assessment of the Breakaway Torque at the Posterior Pelvic Ring in Human Cadavers.

    PubMed

    Bastian, Johannes Dominik; Bergmann, Mathias; Schwyn, Ronald; Keel, Marius Johann Baptist; Benneker, Lorin Michael

    2015-01-01

    To enhance the diminished screw purchase in cancellous, osteoporotic bone following the fixation of posterior pelvic ring injuries by iliosacral screws an increased bone-implant contact area using modificated screws, techniques or bone cement may become necessary. The aim of the study was to identify sites within the pathway of iliosacral screws requiring modifications of the local bone or the design of instrumentations placed at this site. The breakaway torque was measured mechanically at the iliosacral joint ("ISJ"), the sacral lateral mass ("SLM") and the center of the S1 ("CS1"), at a superior and an inferior site under fluoroscopic control on five human cadaveric specimens (3 female; mean age 87 years, range: 76-99) using the DensiProbe™Spine device. The measured median (range) breakaway torque was 0.63 Nm (0.31-2.52) at the "iliosacral joint", 0.14 Nm (0.05-1.22) at the "sacral lateral mass", 0.57 Nm (0.05-1.42) at the "S1 center." The "sacral lateral mass" breakaway torque was lower than compared to that at the "iliosacral joint" (p < .001) or "S1 center" (p < .001). The median (range) breakaway torque measured at all superior measurement points was 0.52 Nm (0.10-2.52), and 0.48 Nm (0.05-1.18) at all inferior sites. The observed difference was statistically significant (p < .05). The lateral mass of the sacrum provides the lowest bone quality for implant anchorage. Iliosacral screws should be placed as superior as safely possible, should bridge the iliosacral joint and may allow for cement application at the lateral mass of the sacrum through perforations.

  20. CT-Guided Transfacet Pedicle Screw Fixation in Facet Joint Syndrome: A Novel Approach

    PubMed Central

    Manfré, Luigi

    2014-01-01

    Summary Axial microinstability secondary to disc degeneration and consequent chronic facet joint syndrome (CFJS) is a well-known pathological entity, usually responsible for low back pain (LBP). Although posterior lumbar fixation (PIF) has been widely used for lumbar spine instability and LBP, complications related to wrong screw introduction, perineural scars and extensive muscle dissection leading to muscle dysfunction have been described. Radiofrequency ablation (RFA) of facet joints zygapophyseal nerves conventionally used for pain treatment fails in approximately 21% of patients. We investigated a “covert-surgery” minimal invasive technique to treat local spinal instability and LBP, using a novel fully CT-guided approach in patients with axial instability complicated by CFJS resistant to radioablation, by introducing direct fully or partially threaded transfacet screws (transfacet fixation - TFF), to acquire solid arthrodesis, reducing instability and LBP. The CT-guided procedure was well tolerated by all patients in simple analogue sedation, and mean operative time was approximately 45 minutes. All eight patients treated underwent clinical and CT study follow-up at two months, revealing LBP disappearance in six patients, and a significant reduction of lumbar pain in two. In conclusion, CT-guided TFF is a fast and safe technique when facet posterior fixation is needed. PMID:25363265

  1. Long-term neuromuscular training and ankle joint position sense.

    PubMed

    Kynsburg, A; Pánics, G; Halasi, T

    2010-06-01

    Preventive effect of proprioceptive training is proven by decreasing injury incidence, but its proprioceptive mechanism is not. Major hypothesis: the training has a positive long-term effect on ankle joint position sense in athletes of a high-risk sport (handball). Ten elite-level female handball-players represented the intervention group (training-group), 10 healthy athletes of other sports formed the control-group. Proprioceptive training was incorporated into the regular training regimen of the training-group. Ankle joint position sense function was measured with the "slope-box" test, first described by Robbins et al. Testing was performed one day before the intervention and 20 months later. Mean absolute estimate errors were processed for statistical analysis. Proprioceptive sensory function improved regarding all four directions with a high significance (p<0.0001; avg. mean estimate error improvement: 1.77 degrees). This was also highly significant (p< or =0.0002) in each single directions, with avg. mean estimate error improvement between 1.59 degrees (posterior) and 2.03 degrees (anterior). Mean absolute estimate errors at follow-up (2.24 degrees +/-0.88 degrees) were significantly lower than in uninjured controls (3.29 degrees +/-1.15 degrees) (p<0.0001). Long-term neuromuscular training has improved ankle joint position sense function in the investigated athletes. This joint position sense improvement can be one of the explanations for injury rate reduction effect of neuromuscular training.

  2. The concentration, gene expression, and spatial distribution of aggrecan in canine articular cartilage, meniscus, and anterior and posterior cruciate ligaments: a new molecular distinction between hyaline cartilage and fibrocartilage in the knee joint.

    PubMed

    Valiyaveettil, Manojkumar; Mort, John S; McDevitt, Cahir A

    2005-01-01

    The concentration, spatial distribution, and gene expression of aggrecan in meniscus, articular cartilage, and the anterior and posterior cruciate ligaments (ACL and PCL) was determined in the knee joints of five mature dogs. An anti-serum against peptide sequences specific to the G1 domain of aggrecan was employed in competitive-inhibition ELISA of guanidine HCl extracts and immunofluorescence microscopy. Gene expression was determined by Taqman real-time PCR. The concentration of aggrecan in articular cartilage (240.1 +/- 32 nMol/g dry weight) was higher than that in meniscus (medial meniscus: 33.4 +/- 4.3 nMol/g) and ligaments (ACL: 6.8 +/- 0.9 nMol/g). Aggrecan was more concentrated in the inner than the outer zone of the meniscus. Aggrecan in meniscus showed an organized, spatial network, in contrast to its diffuse distribution in articular cartilage. Thus, differences in the concentration, gene expression, and spatial distribution of aggrecan constitute another molecular distinction between hyaline cartilage and fibrocartilage of the knee.

  3. Non-Kolmogorovian Approach to the Context-Dependent Systems Breaking the Classical Probability Law

    NASA Astrophysics Data System (ADS)

    Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Yamato, Ichiro

    2013-07-01

    There exist several phenomena breaking the classical probability laws. The systems related to such phenomena are context-dependent, so that they are adaptive to other systems. In this paper, we present a new mathematical formalism to compute the joint probability distribution for two event-systems by using concepts of the adaptive dynamics and quantum information theory, e.g., quantum channels and liftings. In physics the basic example of the context-dependent phenomena is the famous double-slit experiment. Recently similar examples have been found in biological and psychological sciences. Our approach is an extension of traditional quantum probability theory, and it is general enough to describe aforementioned contextual phenomena outside of quantum physics.

  4. Influence of posterior condylar offset on knee flexion after cruciate-sacrificing mobile-bearing total knee replacement: a prospective analysis of 410 consecutive cases.

    PubMed

    Bauer, T; Biau, D; Colmar, M; Poux, X; Hardy, P; Lortat-Jacob, A

    2010-12-01

    The range of motion of the knee joint after Total Knee Replacement (TKR) is a factor of great importance that determines the postoperative function of patients. Much enthusiasm has been recently directed towards the posterior condylar offset with some authors reporting increasing postoperative knee flexion with increasing posterior condylar offset and others who did not report any significant association. Patients undergoing primary total knee replacement were included in a prospective multicentre study and the effect of the posterior condylar offset on the postoperative knee flexion was assessed after adjusting for known influential factors. All knees were implanted by three senior orthopedist surgeons with the same cemented cruciate-sacrificing mobile-bearing implant and with identical surgical technique. Clinical data, active knee flexion and posterior condylar offset were recorded preoperatively and postoperatively at a minimal one year follow-up for all patients. Univariate and multivariate linear models were fitted to select independent predictors of the postoperative knee flexion. Four hundred and ten consecutive total knee replacements (379 patients) were included in the study. The mean preoperative knee flexion was 112°. The mean condylar offset was 28.3mm preoperatively and 29.4mm postoperatively. The mean postoperative knee flexion was 108°. No correlation was found between the posterior condylar offset or the tibial slope and the postoperative knee flexion. The most significant predictive factor for postoperative flexion after posterior-stabilized TKR without PCL retention was the preoperative range of flexion, with a linear effect. Copyright © 2009 Elsevier B.V. All rights reserved.

  5. [Isolated severe neurologic disorders in post-partum: posterior reversible encephalopathy syndrome].

    PubMed

    Wernet, A; Benayoun, L; Yver, C; Bruno, O; Mantz, J

    2007-01-01

    Just after Caesarean section for twin pregnancy and feto-pelvic dysproportion, a woman presented severe headaches and arterial hypertension, then blurred vision, then generalised seizures. There were no oedematous syndrome, proteinuria was negative, ASAT were 1.5 N and platelet count was 120,000/mm(3). Cerebral CT-scan was normal. Posterior reversible encephalopathy syndrome (PRES) was diagnosed on MRI. A second MRI performed at day 9 showed complete regression of cerebral lesions, while patient was taking anti-hypertensive and antiepileptic drugs. PRES has to be evoked in post-partum central neurological symptoms, even in absence of classical sign of pre-eclampsia, like proteinuria. PRES and eclampsia share probably common physiopathological pathways. There management and prognosis seems identical.

  6. Do Transsacral-transiliac Screws Across Uninjured Sacroiliac Joints Affect Pain and Functional Outcomes in Trauma Patients?

    PubMed

    Heydemann, John; Hartline, Braden; Gibson, Mary Elizabeth; Ambrose, Catherine G; Munz, John W; Galpin, Matthew; Achor, Timothy S; Gary, Joshua L

    2016-06-01

    Patients with pelvic ring displacement and instability can benefit from surgical reduction and instrumentation to stabilize the pelvis and improve functional outcomes. Current treatments include iliosacral screw or transsacral-transiliac screw, which provides greater biomechanical stability. However, controversy exists regarding the effects of placement of a screw across an uninjured sacroiliac joint for pelvis stabilization after trauma. Does transsacral-transiliac screw fixation of an uninjured sacroiliac joint increase pain and worsen functional outcomes at minimum 1-year followup compared with patients undergoing standard iliosacral screw fixation across the injured sacroiliac joint in patients who have sustained pelvic trauma? All patients between ages 18 and 84 years who sustained injuries to the pelvic ring (AO/OTA 61 A, B, C) who were surgically treated between 2011 and 2013 at an academic Level I trauma center were identified for selection. We included patients with unilateral sacroiliac disruption or sacral fractures treated with standard iliosacral screws across an injured hemipelvis and/or transsacral-transiliac screws placed in the posterior ring. Transsacral-transiliac screws were generally more likely to be used in patients with vertically unstable sacral injuries of the posterior ring as a result of previous reports of failures or in osteopenic patients. We excluded patients with bilateral posterior pelvic ring injuries, fixation with a device other than a screw, previous pelvic or acetabular fractures, associated acetabular fractures, and ankylosing spondylitis. Of the 110 patients who met study criteria, 53 (44%) were available for followup at least 12 months postinjury. Sixty patients were unable to be contacted by phone or mail and seven declined to participate in the study. Outcomes were obtained by members of the research team using the visual analog scale (VAS) pain score for both posterior sacroiliac joints, Short Musculoskeletal Functional

  7. Glenohumeral joint injection: a comparative study of ultrasound and fluoroscopically guided techniques before MR arthrography.

    PubMed

    Rutten, Matthieu J C M; Collins, James M P; Maresch, Bas J; Smeets, Jacques H J M; Janssen, Caroline M M; Kiemeney, Lambertus A L M; Jager, Gerrit J

    2009-03-01

    To assess the variability in accuracy of contrast media introduction, leakage, required time and patient discomfort in four different centres, each using a different image-guided glenohumeral injection technique. Each centre included 25 consecutive patients. The ultrasound-guided anterior (USa) and posterior approach (USp), fluoroscopic-guided anterior (FLa) and posterior (FLp) approach were used. Number of injection attempts, effect of contrast leakage on diagnostic quality, and total room, radiologist and procedure times were measured. Pain was documented with a visual analogue scale (VAS) pain score. Access to the joint was achieved in all patients. A successful first attempt significantly occurred more often with US (94%) than with fluoroscopic guidance (72%). Leakage of contrast medium did not cause interpretative difficulties. With US guidance mean room, procedure and radiologist times were significantly shorter (p < 0.001). The USa approach was rated with the lowest pre- and post-injection VAS scores. The four image-guided injection techniques are successful in injection of contrast material into the glenohumeral joint. US-guided injections and especially the anterior approach are significantly less time consuming, more successful on the first attempt, cause less patient discomfort and obviate the need for radiation and iodine contrast.

  8. Hip and knee joint loading during vertical jumping and push jerking.

    PubMed

    Cleather, Daniel J; Goodwin, Jon E; Bull, Anthony M J

    2013-01-01

    The internal joint contact forces experienced at the lower limb have been frequently studied in activities of daily living and rehabilitation activities. In contrast, the forces experienced during more dynamic activities are not well understood, and those studies that do exist suggest very high degrees of joint loading. In this study a biomechanical model of the right lower limb was used to calculate the internal joint forces experienced by the lower limb during vertical jumping, landing and push jerking (an explosive exercise derived from the sport of Olympic weightlifting), with a particular emphasis on the forces experienced by the knee. The knee experienced mean peak loadings of 2.4-4.6×body weight at the patellofemoral joint, 6.9-9.0×body weight at the tibiofemoral joint, 0.3-1.4×body weight anterior tibial shear and 1.0-3.1×body weight posterior tibial shear. The hip experienced a mean peak loading of 5.5-8.4×body weight and the ankle 8.9-10.0×body weight. The magnitudes of the total (resultant) joint contact forces at the patellofemoral joint, tibiofemoral joint and hip are greater than those reported in activities of daily living and less dynamic rehabilitation exercises. The information in this study is of importance for medical professionals, coaches and biomedical researchers in improving the understanding of acute and chronic injuries, understanding the performance of prosthetic implants and materials, evaluating the appropriateness of jumping and weightlifting for patient populations and informing the training programmes of healthy populations. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Comparison of the effects of local cryotherapy and passive cross-body stretch on extensibility in subjects with posterior shoulder tightness.

    PubMed

    Park, Kyue-Nam; Kwon, Oh-Yun; Weon, Jong-Hyuck; Choung, Sung-Dae; Kim, Si-Hyun

    2014-01-01

    The objective was to compare the immediate effects of local cryotherapy (LC) and passive cross-body stretch on the extensibility of the posterior shoulder muscle in individuals with posterior shoulder tightness. Eighty-seven healthy subjects with a between-shoulder difference in internal rotation (IR) range of motion (ROM) greater than 10° were randomly divided into three groups: LC group, stretching group, and control group (n = 29 in each group). Subjects in the LC group received LC on infraspinatus and posterior deltoid muscles and subjects in the stretching group performed passive cross-body stretch. Stretch sensation was measured at the end range of passive IR and horizontal adduction (HA) using numerical rating scale, and the pressure pain threshold (PPT) at the infraspinatus and posterior deltoid muscles was measured using pressure algometry. Passive and active ROM of IR and HA of the glenohumeral joint were measured using an inclinometer. All measurements were performed at pre-intervention, post- intervention, and 10-min follow-up. Stretch sensation was significantly decreased and PPT was significantly increased in the LC and stretching groups at post-intervention, and these effects were maintained at 10-min follow-up, compared to the control group. Both the LC group and stretching group had a significantly greater increase in passive and active ROM of IR and HA, compared to the control group at post-intervention and 10-min follow-up. However, there were no significant differences in stretch sensation, PPT, or ROM of IR and HA between the LC group and stretching group. LC can be used to decrease the stretch sensation and increase PPT and ROM of IR and HA as much as a stretching exercise. LC could be an alternative method for increasing the restricted ROM of glenohumeral IR and HA for individuals with posterior shoulder tightness, especially for patients and sports players who have severe stretching discomfort. Key PointsLocal cryotherapy (LC) decreased the

  10. Comparison of the Effects of Local Cryotherapy and Passive Cross-Body Stretch on Extensibility in Subjects with Posterior Shoulder Tightness

    PubMed Central

    Park, Kyue-nam; Kwon, Oh-yun; Weon, Jong-hyuck; Choung, Sung-dae; Kim, Si-hyun

    2014-01-01

    The objective was to compare the immediate effects of local cryotherapy (LC) and passive cross-body stretch on the extensibility of the posterior shoulder muscle in individuals with posterior shoulder tightness. Eighty-seven healthy subjects with a between-shoulder difference in internal rotation (IR) range of motion (ROM) greater than 10° were randomly divided into three groups: LC group, stretching group, and control group (n = 29 in each group). Subjects in the LC group received LC on infraspinatus and posterior deltoid muscles and subjects in the stretching group performed passive cross-body stretch. Stretch sensation was measured at the end range of passive IR and horizontal adduction (HA) using numerical rating scale, and the pressure pain threshold (PPT) at the infraspinatus and posterior deltoid muscles was measured using pressure algometry. Passive and active ROM of IR and HA of the glenohumeral joint were measured using an inclinometer. All measurements were performed at pre-intervention, post- intervention, and 10-min follow-up. Stretch sensation was significantly decreased and PPT was significantly increased in the LC and stretching groups at post-intervention, and these effects were maintained at 10-min follow-up, compared to the control group. Both the LC group and stretching group had a significantly greater increase in passive and active ROM of IR and HA, compared to the control group at post-intervention and 10-min follow-up. However, there were no significant differences in stretch sensation, PPT, or ROM of IR and HA between the LC group and stretching group. LC can be used to decrease the stretch sensation and increase PPT and ROM of IR and HA as much as a stretching exercise. LC could be an alternative method for increasing the restricted ROM of glenohumeral IR and HA for individuals with posterior shoulder tightness, especially for patients and sports players who have severe stretching discomfort. Key Points Local cryotherapy (LC) decreased

  11. A Rare Case of Massive Rotator Cuff Tear and Biceps Tendon Rupture with Posterior Shoulder Dislocation in a Young Adult - Surgical Decision-making and Outcome

    PubMed Central

    Soon, En Loong; Razak, Hamid Rahmatullah Bin Abd; Tan, Andrew Hwee Chye

    2017-01-01

    Introduction: Massive rotator cuff tears (RCTs) in the context of shoulder dislocations are relatively uncommon in the young adult (<40 years) and if reported are more commonly described in association with acute traumatic anterior glenohumeral dislocations. They have rarely been described with posterior dislocations, regardless of patient age. This is the 1st case reported in the context of posterior dislocations, where a triad of biceps tendon rupture, posterior dislocation, and RCTs was observed during surgery. It provides an important reminder to readers about certain injuries commonly overlooked during the assessment of an acute traumatic shoulder. Case Report: We report an atypical case of a massive RCT involving a 34-year-old Asian male who landed on his outstretched hand after falling off a bicycle. A tear involving the supraspinatus and subscapularis was visualized during surgery, along with long head of biceps (LHB) tendon rupture. This was after an initial failure to achieve closed reduction of the posteriorly dislocated left shoulder. Conclusion: It is easy to miss the posterior instability, the associated RCTs or the biceps tendon injuries. Biceps tendon rupture should be a consideration when one is unable to reduce a posteriorly dislocated shoulder. The interposed torn LHB tendon trapped within the glenohumeral joint was the likely physical block in the initial failure to achieve closed reduction. With timely diagnosis, prudent physical examination, early imaging and surgery, and excellent results can potentially be achieved to return a young patient to full functionality. PMID:28819610

  12. The World According to de Finetti: On de Finetti's Theory of Probability and Its Application to Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Berkovitz, Joseph

    Bruno de Finetti is one of the founding fathers of the subjectivist school of probability, where probabilities are interpreted as rational degrees of belief. His work on the relation between the theorems of probability and rationality is among the corner stones of modern subjective probability theory. De Finetti maintained that rationality requires that degrees of belief be coherent, and he argued that the whole of probability theory could be derived from these coherence conditions. De Finetti's interpretation of probability has been highly influential in science. This paper focuses on the application of this interpretation to quantum mechanics. We argue that de Finetti held that the coherence conditions of degrees of belief in events depend on their verifiability. Accordingly, the standard coherence conditions of degrees of belief that are familiar from the literature on subjective probability only apply to degrees of belief in events which could (in principle) be jointly verified; and the coherence conditions of degrees of belief in events that cannot be jointly verified are weaker. While the most obvious explanation of de Finetti's verificationism is the influence of positivism, we argue that it could be motivated by the radical subjectivist and instrumental nature of probability in his interpretation; for as it turns out, in this interpretation it is difficult to make sense of the idea of coherent degrees of belief in, and accordingly probabilities of unverifiable events. We then consider the application of this interpretation to quantum mechanics, concentrating on the Einstein-Podolsky-Rosen experiment and Bell's theorem.

  13. Wide field of view CT and acromioclavicular joint instability: A technical innovation.

    PubMed

    Dyer, David R; Troupis, John M; Kamali Moaveni, Afshin

    2015-06-01

    A 21-year-old female with a traumatic shoulder injury is investigated and managed for symptoms relating to this injury. Pathology at the acromioclavicular joint is detected clinically; however, clinical examination and multiple imaging modalities do not reach a unified diagnosis on the grading of this acromioclavicular joint injury. When management appropriate to that suggested injury grading fail to help the patient's symptoms, further investigation methods were utilised. Wide field of view, dynamic CT (4D CT) is conducted on the patient's affected shoulder using a 320 × 0.5 mm detector multislice CT. Scans were conducted with a static table as the patient completed three movements of the affected shoulder. Capturing multiple data sets per second over a z-axis of 16 cm, measurements of the acromioclavicular joint were made, to show dynamic changes at the joint. Acromioclavicular (AC) joint translations were witnessed in three planes (a previously unrecognised pathology in the grading of acromioclavicular joint injuries). Translation in multiple planes was also not evident on careful clinical examination of this patient. AC joint width, anterior-posterior translation, superior-inferior translation and coracoclavicular width were measured with planar reconstructions while volume-rendered images and dynamic sequences aiding visual understanding of the pathology. Wide field of view dynamic CT (4D CT) is an accurate and quick modality to diagnose complex acromioclavicular joint injury. It provides dynamic information that no other modality can; 4D CT shows future benefits for clinical approach to diagnosis and management of acromioclavicular joint injury, and other musculoskeletal pathologies. © 2015 The Royal Australian and New Zealand College of Radiologists.

  14. Kinematic Analysis of a Posterior-stabilized Knee Prosthesis

    PubMed Central

    Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

    2015-01-01

    Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0–135° flexion. Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, “rollback” compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. PMID:25591565

  15. Kinematic analysis of a posterior-stabilized knee prosthesis.

    PubMed

    Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

    2015-01-20

    The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion. Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis.

  16. Thoracolumbar Junction Syndrome Causing Pain around Posterior Iliac Crest: A Case Report.

    PubMed

    Kim, Soo-Ryu; Lee, Min-Ji; Lee, Seung-Jun; Suh, Young-Sung; Kim, Dae-Hyun; Hong, Ji-Hee

    2013-03-01

    Thoracolumbar junction syndrome is characterized by referred pain which may originate at the thoracolumbar junction, which extends from 12th thoracic vertebra to 2nd lumbar vertebra, due to functional abnormalities. Clinical manifestations include back pain, pseudo-visceral pain and pseudo-pain on the posterior iliac crest, as well as irritable bowel symptoms. During clinical examination, pain can be demonstrated by applying pressure on the facet joints or to the sides of the spinous processes. Radiological studies show only mild and insignificant degenerative changes in most cases. We report a 42-year-old female patient with osteogenesis imperfecta who suffered from chronic low back pain. Under the diagnosis of thoracolumbar junction syndrome, she was treated with an epidural block and a sympathetic nerve block, which improved her symptoms.

  17. Leg symptoms associated with sacroiliac joint disorder and related pain.

    PubMed

    Murakami, Eiichi; Aizawa, Toshimi; Kurosawa, Daisuke; Noguchi, Kyoko

    2017-06-01

    The symptoms of sacroiliac joint (SIJ) disorders are usually detected in the buttock and groin, and occasionally referred to the thigh and leg. However, lumbar disorders also cause symptoms in these same body regions. The presence of a characteristic, symptomatic pattern in the legs would be useful for diagnosing SIJ disorders. This study aimed to identify specific leg symptoms in patients with SIJ pain originating from the posterior sacroiliac ligament and determine the rate of occurrence of these symptoms. The source population consisted of 365 consecutive patients from February 2005 to December 2007. One hundred patients were diagnosed with SIJ pain by a periarticular SIJ injection (42 males and 58 females, average age 46 years, age range, 18-75 years). A leg symptom map was made by subtracting the symptoms after a periarticular SIJ injection from the initial symptoms, and evaluating the rate of each individual symptom by area. Ninety-four patients reported pain at or around the posterior-superior iliac spine (PSIS). Leg symptoms comprised pain and a numbness/tingling sensation; ≥60% of the patients had these symptoms. Pain was mainly detected in the back, buttock, groin, and thigh areas, while numbness/tingling was mainly detected in the lateral to posterior thigh and back of the calf. Leg symptoms associated with SIJ pain originating from the posterior sacroiliac ligament include both pain and numbness, which do not usually correspond to the dermatome. These leg symptoms in addition to pain around the PSIS may indicate SIJ disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Dynamic Sonographic Visualization of an Occult Posterior Lateral Meniscocapsular Separation: A Case Report.

    PubMed

    Schroeder, Allison; Musahl, Volker; Urbanek, Christopher; Onishi, Kentaro

    2018-04-05

    Meniscocapsular separation describes detachment of the meniscus from the knee joint capsule. Diagnosis is challenging with conventional examination and imaging methods. We report a case of an 18-year-old female softball catcher with unrevealing magnetic resonance imaging despite continued left knee locking and discomfort with deep squatting. Meniscocapsular separation was revealed only on dynamic sonographic exam, where knee flexion revealed a 3.1-mm gap that developed between the capsule and peripheral meniscus. Arthroscopy confirmed the sonographic findings, and repair resulted in complete resolution of symptoms. This case highlights the utility of dynamic diagnostic sonography in a rare case of posterior lateral meniscocapsular separation. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  19. Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants vs Nonsurgical Management for Sacroiliac Joint Dysfunction: 12-Month Outcomes

    PubMed Central

    Polly, David W.; Wine, Kathryn D.; Whang, Peter G.; Frank, Clay J.; Harvey, Charles F.; Lockstadt, Harry; Glaser, John A.; Limoni, Robert P.; Sembrano, Jonathan N.

    2015-01-01

    BACKGROUND: Sacroiliac joint (SIJ) dysfunction is a prevalent cause of chronic, unremitting lower back pain. OBJECTIVE: To concurrently compare outcomes after surgical and nonsurgical treatment for chronic SIJ dysfunction. METHODS: A total of 148 subjects with SIJ dysfunction were randomly assigned to minimally invasive SIJ fusion with triangular titanium implants (n = 102) or nonsurgical management (n = 46). Pain, disability, and quality-of-life scores were collected at baseline and at 1, 3, 6, and 12 months. Success rates were compared using Bayesian methods. Crossover from nonsurgical to surgical care was allowed after the 6-month study visit was complete. RESULTS: Six-month success rates were higher in the surgical group (81.4% vs 26.1%; posterior probability of superiority > 0.9999). Clinically important (≥ 15 point) Oswestry Disability Index improvement at 6 months occurred in 73.3% of the SIJ fusion group vs 13.6% of the nonsurgical management group (P < .001). At 12 months, improvements in SIJ pain and Oswestry Disability Index were sustained in the surgical group. Subjects who crossed over had improvements in pain, disability, and quality of life similar to those in the original surgical group. Adverse events were slightly more common in the surgical group (1.3 vs 1.1 events per subject; P = .31). CONCLUSION: This Level 1 study showed that minimally invasive SIJ fusion using triangular titanium implants was more effective than nonsurgical management at 1 year in relieving pain, improving function, and improving quality of life in patients with SIJ dysfunction caused by degenerative sacroiliitis or SIJ disruptions. Pain, disability, and quality of life also improved after crossover from nonsurgical to surgical treatment. ABBREVIATIONS: EQ-5D, EuroQoL-5D INSITE, Investigation of Sacroiliac Fusion Treatment MCS, mental component summary NSM, nonsurgical management ODI, Oswestry Disability Index PCS, physical component summary RFA, radiofrequency ablation SF

  20. [Arthroscopic therapy of ankle joint impingement syndrome after operation of ankle joint fracture dislocation].

    PubMed

    Feng, Zhibin; Mi, Kun; Wei, Renzhi; Liu, Wu; Wang, Bin

    2011-07-01

    To study the operative procedure and the effectiveness of arthroscopic therapy for ankle joint impingement syndrome after operation of ankle joint fracture dislocation. Between March 2008 and April 2010, 38 patients with ankle joint impingement syndrome after operation of ankle joint fracture dislocation were treated. Among them, there were 28 males and 10 females with an average age of 28 years (range, 18 to 42 years). The time from internal fixation to admission was 12-16 months (mean, 13.8 months). There were pressing pain in anterolateral and anterior ankle. The dorsal extension ranged from -20 to -5 degrees (mean, -10.6 degrees), and the palmar flexion was 30-40 degrees (mean, 35.5 degrees). The total score was 48.32 +/- 9.24 and the pain score was 7.26 +/- 1.22 before operation according to American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score system. The X-ray films showed osteophyte formation in anterior tibia and talus; MRI showed cartilage injury in 22 cases. Arthroscopic intervention included removing osteophytes, debriding fabric scars and synovial membrane tissues, and removing osteochondral fragments. Arthroscopic microfracture technique was used in 22 patients with cartilage injury. All incisions healed primarily. Thirty-eight cases were followed up 10-26 months (mean, 16 months). At last follow-up, 26 patients had normal range of motion (ROM); the dorsal extension was 15-25 degrees (mean, 19.6 degrees) and the palmar flexion was 35-45 degrees (mean, 40.7 degrees). Eight patients had mild limited ROM; the dorsal extension was 5-15 degrees (mean, 7.2 degrees) and the palmar flexion was 35-45 degrees (mean, 39.5 degrees). Four patients had mild limited ROM and pain in posterior portion of the ankle after a long walking (3-4 hours); the dorsal extension was 0-5 degrees (mean, 2.6 degrees) and the palmar flexion was 35-40 degrees (mean, 37.5 degrees). The total score was 89.45 +/- 9.55 and the pain score was 1.42 +/- 1.26 after

  1. Proximal dentatothalamocortical tract involvement in posterior fossa syndrome

    PubMed Central

    Phillips, Nicholas S.; Laningham, Fred H.; Patay, Zoltan; Gajjar, Amar; Wallace, Dana; Boop, Frederick; Sanford, Robert; Ness, Kirsten K.; Ogg, Robert J.

    2009-01-01

    Posterior fossa syndrome is characterized by cerebellar dysfunction, oromotor/oculomotor apraxia, emotional lability and mutism in patients after infratentorial injury. The underlying neuroanatomical substrates of posterior fossa syndrome are unknown, but dentatothalamocortical tracts have been implicated. We used pre- and postoperative neuroimaging to investigate proximal dentatothalamocortical tract involvement in childhood embryonal brain tumour patients who developed posterior fossa syndrome following tumour resection. Diagnostic imaging from a cohort of 26 paediatric patients previously operated on for an embryonal brain tumour (13 patients prospectively diagnosed with posterior fossa syndrome, and 13 non-affected patients) were evaluated. Preoperative magnetic resonance imaging was used to define relevant tumour features, including two potentially predictive measures. Postoperative magnetic resonance and diffusion tensor imaging were used to characterize operative injury and tract-based differences in anisotropy of water diffusion. In patients who developed posterior fossa syndrome, initial tumour resided higher in the 4th ventricle (P = 0.035). Postoperative magnetic resonance signal abnormalities within the superior cerebellar peduncles and midbrain were observed more often in patients with posterior fossa syndrome (P = 0.030 and 0.003, respectively). The fractional anisotropy of water was lower in the bilateral superior cerebellar peduncles, in the bilateral fornices, white matter region proximate to the right angular gyrus (Tailerach coordinates 35, –71, 19) and white matter region proximate to the left superior frontal gyrus (Tailerach coordinates –24, 57, 20). Our findings suggest that multiple bilateral injuries to the proximal dentatothalamocortical pathways may predispose the development of posterior fossa syndrome, that functional disruption of the white matter bundles containing efferent axons within the superior cerebellar peduncles is a

  2. Convex Hemiepiphysiodesis: Posterior/anterior in-situ Versus Posterior-only With Pedicle Screw Instrumentation: An Experimental Simulation in Immature Pigs.

    PubMed

    Bekmez, Senol; Demirkiran, Halil G; Yilmaz, Guney; Akel, Ibrahim; Atilla, Pergin; Muftuoglu, Sevda Fatma; Yazici, Muharrem; Alanay, Ahmet

    2016-12-01

    Experimental study. Convex growth arrest (CGA) has been commonly used in the treatment of long-sweeping congenital deformities of the immature spine. As there are major drawbacks about the anterior procedure in the conventional CGA method, a new modification has been documented that using only posterior spinal approach with pedicle screw instrumentation. The aim of the study was to compare posterior-only CGA using pedicle screws with combined anterior/posterior in-situ CGA for the findings in histologic, radiologic, and manual palpation examinations in an immature pig model. Twelve 10-weeks old pigs were grouped into 2. In group 1, posterior-only, pedicle screw instrumented CGA was performed on the left side of L1-L4 vertebrae. In group 2, conventional combined posterior and anterior CGA was performed to the left side of L1-L4 vertebrae without instrumentation. All animals were killed twelve weeks after surgery. T11-L5 segments were en-bloc resected and radiologic, histologic, and manual palpation examinations were done. Marked scoliotic (12.2±2.5 and 9.2±1.3 in group 1 and 2, respectively) and kyphotic (11.2±1.0 degrees for the group 1 and 12±5.2 degrees for the group 2, respectively) deformities were noted in both groups, which were caused by hemiepiphysiodesis effect. Anterior and posterior parts of group 2 and posterior part of group 1 demonstrated fusion in histologic and radiologic analyzes. In anterior part of the group 1, marked narrowing on the disk spaces and thinning of growth plates were noted in radiologicg examination, chondrocyte degeneration, and newly-formed bone trabeculae in disk-space were noted in histological examination. In manual palpation, no motion was detected in group 1 and motion was detected in only one segment of one animal in group 2. Anterior growth of the vertebrae can be controlled by application of posterior transpedicular screws and rod. Such an effect can eliminate the need for anterior surgical intervention in convex

  3. Isolated transient vertigo: posterior circulation ischemia or benign origin?

    PubMed

    Blasberg, Tobias F; Wolf, Lea; Henke, Christian; Lorenz, Matthias W

    2017-06-14

    Isolated transient vertigo can be the only symptom of posterior circulation ischemia. Thus, it is important to differentiate isolated vertigo of a cerebrovascular origin from that of more benign origins, as patients with cerebral ischemia have a much higher risk for future stroke than do those with 'peripheral' vertigo. The current study aims to identify risk factors for cerebrovascular origin of isolated transient vertigo, and for future cerebrovascular events. From the files of 339 outpatients with isolated transient vertigo we extracted history, clinical and technical findings, diagnosis, and follow-up information on subsequent stroke or transient ischemic attack (TIA). Risk factors were analyzed using multivariate regression models (logistic or Cox) and reconfirmed in univariate analyses. On first presentation, 48 (14.2%) patients received the diagnosis 'probable or definite cerebrovascular vertigo'. During follow-up, 41 patients suffered stroke or TIA (event rate 7.9 per 100 person years, 95% confidence interval (CI) 5.5-10.4), 26 in the posterior circulation (event rate 4.8 per 100 person years, 95% CI 3.0-6.7). The diagnosis was not associated with follow-up cerebrovascular events. In multivariate models testing multiple potential determinants, only the presentation mode was consistently associated with the diagnosis and stroke risk: patients who presented because of vertigo (rather than reporting vertigo when they presented for other reasons) had a significantly higher risk for future stroke or TIA (p = 0.028, event rate 13.4 vs. 5.4 per 100 person years) and for future posterior circulation stroke or TIA (p = 0.044, event rate 7.8 vs. 3.5 per 100 person years). We here report for the first time follow-up stroke rates in patients with transient isolated vertigo. In such patients, the identification of those with cerebrovascular origin remains difficult, and presentation mode was found to be the only consistent risk factor. Confirmation in an independent

  4. On the relationship between lower extremity muscles activation and peak vertical and posterior ground reaction forces during single leg drop landing.

    PubMed

    Mahaki, M; Mi'mar, R; Mahaki, B

    2015-10-01

    Anterior cruciate ligament (ACL) injury continues to be an important medical issue for athletes participating in sports. Vertical and posterior ground reaction forces have received considerable attention for their potential influence on ACL injuries. The purpose of this study was to examine the relationship between electromyographic activity of lower extremity muscles and the peak vertical and posterior ground reaction forces during single leg drop landing. Thirteen physical education male students participated in this correlation study. Electromyographic activities of gluteus medius, biceps femoris, medial gastrocnemius, soleus as well as anterior tibialis muscles along with ground reaction forces were measured. Participants performed single-leg landing from a 0.3 m height on to a force platform. Landing was divided into two phases: 100 ms preceding ground contact and 100 ms proceeding ground contact. Pearson correlation test was used to determine the relationships between these muscles activity and peak vertical and posterior ground reaction forces. The results of the study indicated that the activity of soleus and tibialis anterior in pre-landing phase were positively correlated with peak vertical ground reaction force ([P≤0.04], [P≤0.008], respectively). However, no significant correlation was found between the activities of other muscles in pre-landing phase and peak vertical as well as peak posterior ground reaction forces. Also, no significant correlation was found between the activities of muscles in post-landing phase and peak vertical as well as peak posterior ground reaction forces. Soleus loading shifts the proximal tibia posterior at the knee joint and tibialis anterior prevent hyperporonation of the ankle, a mechanisms of ACL injury. Hence, neuromuscular training promoting preparatory muscle activity in these muscles may reduce the incidence of ACL injuries.

  5. Unilateral posterior crossbite and mastication.

    PubMed

    Rilo, Benito; da Silva, José Luis; Mora, María Jesús; Cadarso-Suárez, Carmen; Santana, Urbano

    2007-05-01

    This study was designed to characterize masticatory-cycle morphology, and distance of the contact glide in the closing masticatory stroke, in adult subjects with uncorrected unilateral posterior crossbite (UPXB), comparing the results obtained with those obtained in a parallel group of normal subjects. Mandibular movements (masticatory movements and laterality movements with dental contact) were registered using a gnathograph (MK-6I Diagnostic System) during unilateral chewing of a piece of gum. Traces were recorded on the crossbite and non-crossbite sides in the crossbite group, and likewise on both sides in the non-crossbite group. Mean contact glide distance on the crossbite side in the UPXB group was significantly lower than in the control group (p<0.001), and mean contact glide distance on the non-crossbite side in the UPXB group was significantly lower than in the control group (p=0.042). Cycle morphology was abnormal during chewing on the crossbite side, with the frequency distribution of cycle types differing significantly from that for the noncrossbite side and that for the control group (p<0.001). Patients with crossbite showed alterations in both contact glide distances and masticatory cycle morphology. These alterations are probably adaptive responses allowing maintenance of adequate masticatory function despite the crossbite.

  6. [Posterior ankle impingement syndrome].

    PubMed

    Bojanić, Ivan; Janjić, Tamara; Dimnjaković, Damjan; Križan, Sanja; Smoljanović, Tomislav

    2015-01-01

    Posterior ankle impingement syndrome (PAIS) is a clinical syndrome characterized by posterior ankle pain which occurs in maximal forced plantar flexion of the foot. PAIS can be the result of an acute injury of the ankle, which is more often in general population, or it can be the result of the overuse syndrome, which is more often in athletes and ballet dancers. The etiology of PAIS may involve bony structures or soft tissue structures, or, more often, the combination of both. The diagnosis of PAIS is based on patient's clinical history and physical examination with the hyperplantarflexion test as a very important part of it. Physical examination should be completed with imaging techniques, which most often include magnetic resonance imaging (MRI) or computed tomography (CT) to confirm the diagnosis of PAIS. Conservative treatment is recommended as the primary treatment strategy. In those cases where 3 to 6 months of conservative treatment fails, open or, more often, arthroscopic/endoscopic surgery may be recommended. Nowadays, a 2-portal endoscopic approach introduced by van Dijk et al. in 2000 is the method of choice for the treatment of posterior ankle impingement syndrome.

  7. Posterior reversible encephalopathy syndrome in IgA vasculitis: Neuroimaging of a 14-year-old child.

    PubMed

    Arslan, Harun; Yavuz, Alpaslan; Arslan, Ayşe; Aycan, Abdurrahman

    IgA vasculitis (IgAV) is a leukocytoclastic vasculitis and characterized by involvement of small vessels in skin, gastrointestinal system, joints, kidneys, and less frequently other organs. It is the commonest vasculitis in childhood and etiology is not completely known. Neurological manifestations of IgAV are very rare and usually seen in patients with severe hypertension or as an uncommon feature such as peripheral neuropathy. Posterior reversible encephalopathy syndrome (PRES) is a clinic-radiologic entity characterized with temporary vasogenic edema developing typically in posterior circulation of the brain and has been reported as a rare manifestation of IgAV. In this paper, a PRES case of 14-year-old male with IgAV is reported and etiopathogenesis was discussed with literature. Diagnosis was made by magnetic resonance imaging because of the existence of neurological symptoms (headache and visual loss) during the course of disease. His radiological findings have resolved with therapy. Although neurological involvement is a rare manifestation in IgAV, we recommend magnetic resonance imaging in such patients for diagnosis and evaluation of complications. Copyright © 2017. Published by Elsevier Urban & Partner Sp. z o.o.

  8. Posterior capsular rent: Prevention and management.

    PubMed

    Chakrabarti, Arup; Nazm, Nazneen

    2017-12-01

    This review article deals with a potentially sight threatening complication - rupture of the posterior capsule - during cataract surgery. Cataract surgery is the most commonly performed surgical procedure in ophthalmology and despite tremendous technical and technological advancements, posterior capsular rent (PCR) still occurs. PCR occurs both in the hands of experienced senior surgeons and the neophyte surgeons, although with a higher frequency in the latter group. Additionally, certain types of cataracts are prone to this development. If managed properly in a timely manner the eventual outcome may be no different from that of an uncomplicated case. However, improper management may lead to serious complications with a higher incidence of permanent visual disability. The article covers the management of posterior capsular rent from two perspectives: 1. Identifying patients at higher risk and measures to manage such patients by surgical discipline, and 2. Intraoperative management of posterior capsular rent and various case scenarios to minimize long-term complications.This review is written for experienced and not-so-experienced eye surgeons alike to understand and manage PCR.

  9. Probability and possibility-based representations of uncertainty in fault tree analysis.

    PubMed

    Flage, Roger; Baraldi, Piero; Zio, Enrico; Aven, Terje

    2013-01-01

    Expert knowledge is an important source of input to risk analysis. In practice, experts might be reluctant to characterize their knowledge and the related (epistemic) uncertainty using precise probabilities. The theory of possibility allows for imprecision in probability assignments. The associated possibilistic representation of epistemic uncertainty can be combined with, and transformed into, a probabilistic representation; in this article, we show this with reference to a simple fault tree analysis. We apply an integrated (hybrid) probabilistic-possibilistic computational framework for the joint propagation of the epistemic uncertainty on the values of the (limiting relative frequency) probabilities of the basic events of the fault tree, and we use possibility-probability (probability-possibility) transformations for propagating the epistemic uncertainty within purely probabilistic and possibilistic settings. The results of the different approaches (hybrid, probabilistic, and possibilistic) are compared with respect to the representation of uncertainty about the top event (limiting relative frequency) probability. Both the rationale underpinning the approaches and the computational efforts they require are critically examined. We conclude that the approaches relevant in a given setting depend on the purpose of the risk analysis, and that further research is required to make the possibilistic approaches operational in a risk analysis context. © 2012 Society for Risk Analysis.

  10. Imageological measurement of the sternoclavicular joint and its clinical application.

    PubMed

    Li, Ming; Wang, Bo; Zhang, Qi; Chen, Wei; Li, Zhi-Yong; Qin, Shi-Ji; Zhang, Ying-Ze

    2012-01-01

    Dislocation of the sternoclavicular joint is rare. However, posterior dislocation compressing important structures in the mediastinum may be fatal. Early diagnosis and prompt therapy of sternoclavicular joint dislocation are important. Computed tomography (CT) is an optimal means to investigate sternoclavicular joint anatomy; however, there are few reports on the imageological anatomical features of the sternoclavicular joint. The study investigated imageological anatomical features, and a new plate was devised according to these data to treat sternoclavicular joint dislocation. Fifty-three healthy Chinese volunteers examined with chest CT were included in the study. The coronal, sagittal, and axial images of the sternoclavicular region were reconstructed. The sternal head diameter in the inferolateral-to-superomedial direction, length of the clavicular notch, and angle between the clavicular notch and sternum were measured on coronal images. The angle between the presternum and trunk was measured on sagittal images. The following dimensions were measured on axial images: anteroposterior dimensions of the sternal head, clavicular notch, and presternum; width of the sternoclavicular joint; distance between bilateral clavicles; and minimal distance from the presternum to the underlying structures in the thoracic cavity. A new plate was designed according to the above data and was used to repair six sternoclavicular joint dislocations. All cases were followed up with a range of 9 to 12 months. The proximal clavicle is higher than the presternum in a horizontal position. On axial images, the anteroposterior dimension of the sternal head was longer than the presternum, and the center region of the presternum was thinner than the edges. The left sternoclavicular joint space was (0.82 ± 0.21) cm, and the right was (0.87 ± 0.22) cm. Among the structures behind the sternum, the left bilateral innominate vein ran nearest to the presternum. The distance from the anterior

  11. Traumatic synovitis in a classical guitarist: a study of joint laxity.

    PubMed

    Bird, H A; Wright, V

    1981-04-01

    A classical guitarist performing for at least 5 hours each day developed a traumatic synovitis at the left wrist joint that was first erroneously considered to be rheumatoid arthritis. Comparison with members of the same guitar class suggested that unusual joint laxity of the fingers and wrist, probably inherited from the patient's father, was of more importance in the aetiology of the synovitis than a wide range of movement acquired by regular practice. Hyperextension of the metacarpophalangeal joint of the left index finger, quantified by the hyperextensometer, was less marked in the guitarists than in 100 normal individuals. This may be attributed to greater muscular control of the fingers. Lateral instability in the loaded joint may be the most important factor in the aetiology of traumatic synovitis.

  12. One-stage posterior transforaminal lumbar debridement, 360° interbody fusion, and posterior instrumentation in treating lumbosacral spinal tuberculosis.

    PubMed

    Pang, Xiaoyang; Wu, Ping; Shen, Xiongjie; Li, Dongzhe; Luo, Chenke; Wang, Xiyang

    2013-08-01

    Retrospective analysis of the clinical study efficacy and feasibility of one-stage posterior transforaminal lumbar debridement, 360° interbody fusion, and posterior instrumentation in treating lumbosacral spinal tuberculosis. A total of 21 patients with lumbosacral tuberculosis (TB) collected from January 2004 to January 2010, underwent one-stage posterior transforaminal lumbar debridement, 360° interbody fusion, and posterior instrumentation. In addition, the clinical efficacy was evaluated based on the data on the lumbo-sacral angle, neuro-logical status that was recorded by American Spinal Injury Association (ASIA) Impairment Scale, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), which were collected at specific time points. All cases were followed up for 16-36 months (average 24.9 ± 6.44 months). 18 patients suffered from evident neurological deficits preoperatively, of which 16 patients returned to normal at the final follow-up. Two patients with neurological dysfunction aggravated postoperative, experienced significant partial neurological recovery. With an effective and standard anti-TB chemotherapy treated, the values of ESR and CRP returned to normal levels 3-month later postoperative and maintained till the final follow-up. Preoperative lumbosacral angle was 20.89 ± 2.32° and returned 29.62 ± 1.41° postoperative. During long-term follow-up, there was only 1-3° lumbosacral angle loss. There was a significant difference between preoperative and postoperative lumbosacral angles. With effective and standard anti-TB chemotherapy, one-stage posterior transforaminal lumbar debridement, 360° interbody fusion, and posterior instrumentation for lumbosacral tuberculosis can effectively relieve pain symptoms, improve neurological function, and reconstruct the spinal stability.

  13. Posterior Urethroplasty Complexity and Prognosis Can be Described by a Novel Method: Posterior Urethral Stenosis Score.

    PubMed

    Wang, Lin; Lv, Xiangguo; Jin, Chongrui; Guo, Hailin; Shu, Huiquan; Fu, Qiang; Sa, Yinglong

    2018-02-01

    To develop a standardized PU-score (posterior urethral stenosis score), with the goal of using this scoring system as a preliminary predictor of surgical complexity and prognosis of posterior urethral stenosis. We retrospectively reviewed records of all patients who underwent posterior urethral surgery at our institution from 2013 to 2015. The PU-score is based on 5 components, namely etiology (1 or 2 points), location (1-3 points), length (1-3 points), urethral fistula (1 or 2 points), and posterior urethral false passage (1 point). We calculated the score of all patients and analyzed its association with surgical complexity, stenosis recurrence, intraoperative blood loss, erectile dysfunction, and urinary incontinence. There were 144 patients who underwent low complexity urethral surgery (direct vision internal urethrotomy, anastomosis with or without crural separation) with a mean score of 5.1 points, whereas 143 underwent high complexity urethroplasty (anastomosis with inferior pubectomy or urethrorectal fistula repair, perineal or scrotum skin flap urethroplasty, bladder flap urethroplasty) with a mean score of 6.9 points. The increase of PU-score was predictive of higher surgical complexity (P = .000), higher recurrence (P = .002), more intraoperative blood loss (P = .000), and decrease of preoperative (P = .037) or postoperative erectile function (P = .047). However, no association was observed between PU-score and urinary incontinence (P = .213). The PU-score is a novel and meaningful scoring system that describes the essential factors in determining the complexity and prognosis for posterior urethral stenosis. Copyright © 2017. Published by Elsevier Inc.

  14. Scalable posterior approximations for large-scale Bayesian inverse problems via likelihood-informed parameter and state reduction

    NASA Astrophysics Data System (ADS)

    Cui, Tiangang; Marzouk, Youssef; Willcox, Karen

    2016-06-01

    Two major bottlenecks to the solution of large-scale Bayesian inverse problems are the scaling of posterior sampling algorithms to high-dimensional parameter spaces and the computational cost of forward model evaluations. Yet incomplete or noisy data, the state variation and parameter dependence of the forward model, and correlations in the prior collectively provide useful structure that can be exploited for dimension reduction in this setting-both in the parameter space of the inverse problem and in the state space of the forward model. To this end, we show how to jointly construct low-dimensional subspaces of the parameter space and the state space in order to accelerate the Bayesian solution of the inverse problem. As a byproduct of state dimension reduction, we also show how to identify low-dimensional subspaces of the data in problems with high-dimensional observations. These subspaces enable approximation of the posterior as a product of two factors: (i) a projection of the posterior onto a low-dimensional parameter subspace, wherein the original likelihood is replaced by an approximation involving a reduced model; and (ii) the marginal prior distribution on the high-dimensional complement of the parameter subspace. We present and compare several strategies for constructing these subspaces using only a limited number of forward and adjoint model simulations. The resulting posterior approximations can rapidly be characterized using standard sampling techniques, e.g., Markov chain Monte Carlo. Two numerical examples demonstrate the accuracy and efficiency of our approach: inversion of an integral equation in atmospheric remote sensing, where the data dimension is very high; and the inference of a heterogeneous transmissivity field in a groundwater system, which involves a partial differential equation forward model with high dimensional state and parameters.

  15. Multimodal infiltration of local anaesthetic in total knee arthroplasty; is posterior capsular infiltration worth the risk? a prospective, double-blind, randomised controlled trial.

    PubMed

    Pinsornsak, P; Nangnual, S; Boontanapibul, K

    2017-04-01

    Multimodal infiltration of local anaesthetic provides effective control of pain in patients undergoing total knee arthroplasty (TKA). There is little information about the added benefits of posterior capsular infiltration (PCI) using different combinations of local anaesthetic agents. Our aim was to investigate the effectiveness of the control of pain using multimodal infiltration with and without infiltration of the posterior capsule of the knee. In a double-blind, randomised controlled trial of patients scheduled for unilateral primary TKA, 86 were assigned to be treated with multimodal infiltration with (Group I) or without (Group II) PCI. Routine associated analgesia included the use of bupivacaine, morphine, ketorolac and epinephrine. All patients had spinal anaesthesia and patient-controlled analgesia (PCA) post-operatively. A visual analogue scale (VAS) for pain and the use of morphine were recorded 24 hours post-operatively. Side effects of the infiltration, blood loss, and length of stay in hospital were recorded. There were no statistically significant differences between the groups in relation to: VAS pain scores in the first 24 hours post-operatively (p = 0.693), the use of morphine in the PCA (p = 0.647), blood loss (p = 0.625), and length of stay (p = 0.17). There were no neurovascular complications in either group. The multimodal infiltration of local anaesthetic with infiltration of the posterior capsule did not provide significant added analgesic benefits or reduce the use of morphine after TKA. Multimodal infiltration is a satisfactory technique for the management of pain in these patients without the attendant risks of PCI. Cite this article: Bone Joint J 2017; 99-B:483-8. ©2017 The British Editorial Society of Bone & Joint Surgery.

  16. Probability modeling of the number of positive cores in a prostate cancer biopsy session, with applications.

    PubMed

    Serfling, Robert; Ogola, Gerald

    2016-02-10

    Among men, prostate cancer (CaP) is the most common newly diagnosed cancer and the second leading cause of death from cancer. A major issue of very large scale is avoiding both over-treatment and under-treatment of CaP cases. The central challenge is deciding clinical significance or insignificance when the CaP biopsy results are positive but only marginally so. A related concern is deciding how to increase the number of biopsy cores for larger prostates. As a foundation for improved choice of number of cores and improved interpretation of biopsy results, we develop a probability model for the number of positive cores found in a biopsy, given the total number of cores, the volumes of the tumor nodules, and - very importantly - the prostate volume. Also, three applications are carried out: guidelines for the number of cores as a function of prostate volume, decision rules for insignificant versus significant CaP using number of positive cores, and, using prior distributions on total tumor size, Bayesian posterior probabilities for insignificant CaP and posterior median CaP. The model-based results have generality of application, take prostate volume into account, and provide attractive tradeoffs of specificity versus sensitivity. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Synchrony in Joint Action Is Directed by Each Participant’s Motor Control System

    PubMed Central

    Noy, Lior; Weiser, Netta; Friedman, Jason

    2017-01-01

    In this work, we ask how the probability of achieving synchrony in joint action is affected by the choice of motion parameters of each individual. We use the mirror game paradigm to study how changes in leader’s motion parameters, specifically frequency and peak velocity, affect the probability of entering the state of co-confidence (CC) motion: a dyadic state of synchronized, smooth and co-predictive motions. In order to systematically study this question, we used a one-person version of the mirror game, where the participant mirrored piece-wise rhythmic movements produced by a computer on a graphics tablet. We systematically varied the frequency and peak velocity of the movements to determine how these parameters affect the likelihood of synchronized joint action. To assess synchrony in the mirror game we used the previously developed marker of co-confident (CC) motions: smooth, jitter-less and synchronized motions indicative of co-predicative control. We found that when mirroring movements with low frequencies (i.e., long duration movements), the participants never showed CC, and as the frequency of the stimuli increased, the probability of observing CC also increased. This finding is discussed in the framework of motor control studies showing an upper limit on the duration of smooth motion. We confirmed the relationship between motion parameters and the probability to perform CC with three sets of data of open-ended two-player mirror games. These findings demonstrate that when performing movements together, there are optimal movement frequencies to use in order to maximize the possibility of entering a state of synchronized joint action. It also shows that the ability to perform synchronized joint action is constrained by the properties of our motor control systems. PMID:28443047

  18. Osteophyte formation after ACL rupture in mice is associated with joint restabilization and loss of range of motion

    PubMed Central

    Hsia, Allison W.; Anderson, Matthew J.; Heffner, Mollie A.; Lagmay, Earl P.; Zavodovskaya, Regina; Christiansen, Blaine A.

    2016-01-01

    Osteophytes are a typical radiographic finding during osteoarthritis (OA). Osteophytes are thought to form in response to joint instability, however the time course of osteophyte formation and joint stabilization following joint injury is not well understood. In this study, we investigated the time course of osteophyte formation and joint function following non-invasive knee injury in mice. We hypothesized that initial joint instability following knee injury would initiate osteophyte formation, which would in turn restabilize the joint and reduce range of motion (ROM). Mice were subjected to non-invasive anterior cruciate ligament (ACL) rupture. Anterior-posterior (AP) joint laxity, ROM, and chondro/osteophyte formation were measured immediately after injury, and 2, 4, 6, and 8 weeks post-injury. Chondrophyte areas at each time point were measured with histology, while mineralized osteophyte volume was determined using micro-computed tomography. Immediately after ACL rupture, AP joint laxity was increased 2-fold, while ROM was increased 11.7%. Chondrophytes appeared by 2 weeks post-injury, corresponding with a decrease in AP joint laxity and ROM. By 8 weeks post-injury, considerable osteophyte formation was observed around the joint, AP joint laxity returned to control levels, and joint ROM decreased to 61% of control values. These data support a role for chondro/osteophytes in joint restabilization after injury, and provide crucial insight into the time course and pathology of joint degeneration during OA development in the mouse. PMID:27031945

  19. Early endoscopic realignment in posterior urethral injuries.

    PubMed

    Shrestha, B; Baidya, J L

    2013-01-01

    Posterior urethral injury requires meticulous tertiary care and optimum expertise to manage successfully. The aim of our study is to describe our experiences with pelvic injuries involving posterior urethra and their outcome after early endoscopic realignment. A prospective study was carried out in 20 patients with complete posterior urethral rupture, from November 2007 till October 2010. They presented with blunt traumatic pelvic fracture and underwent primary realignment of posterior urethra in our institute. The definitive diagnosis of urethral rupture was made after retrograde urethrography and antegrade urethrography where applicable. The initial management was suprapubic catheter insertion after primary trauma management in casualty. After a week of conservative management with intravenous antibiotics and pain management, patients were subjected to the endoscopic realignment. The follow up period was at least six months. The results were analyzed with SPSS software. After endoscopic realignment, all patients were advised CISC for the initial 3 months. All patients voided well after three months of CISC. However, 12 patients were lost to follow up by the end of 6 postoperative months. Out of eight remaining patients, two had features of restricture and were managed with DVU followed by CISC again. One patient with restricture had some degree of erectile dysfunction who improved significantly after phospodiesterase inhibitors. None of the patients had features of incontinence. Early endoscopic realignment of posterior urethra is a minimally invasive modality in the management of complete posterior urethral injury with low rates of incontinence and impotency.

  20. Numerical simulation of artificial hip joint motion based on human age factor

    NASA Astrophysics Data System (ADS)

    Ramdhani, Safarudin; Saputra, Eko; Jamari, J.

    2018-05-01

    Artificial hip joint is a prosthesis (synthetic body part) which usually consists of two or more components. Replacement of the hip joint due to the occurrence of arthritis, ordinarily patients aged or older. Numerical simulation models are used to observe the range of motion in the artificial hip joint, the range of motion of joints used as the basis of human age. Finite- element analysis (FEA) is used to calculate stress von mises in motion and observes a probability of prosthetic impingement. FEA uses a three-dimensional nonlinear model and considers the position variation of acetabular liner cups. The result of numerical simulation shows that FEA method can be used to analyze the performance calculation of the artificial hip joint at this time more accurate than conventional method.

  1. The posterior cervical lymph node in toxoplasmosis.

    PubMed

    Gray, G F; Kimball, A C; Kean, B H

    1972-11-01

    Posterior cervical node enlargement is characteristic of clinical toxoplasmosis in adults. Lymph node biopsies from 37 patients, who were tested for toxoplasmosis by serologic and isolation studies, were examined. A characteristic pattern of sinus histiocytosis was seen in 17 of 18 posterior cervical nodes and in only 1 of 4 lymph nodes from other sites from patients with toxoplasmosis. The characteristic pattern was not seen in posterior cervical nodes or in lymph nodes from other sites from patients with other diseases. Lymphoma obscured the characteristic changes of toxoplasmosis in the posterior cervical nodes and other nodes of 5 patients with these coexisting diseases. Organisms were seen in tissue sections in only 2 instances. T gondii was isolated from mice in 14 of 17 attempts using nodes from patients with toxoplasmosis, but from none of 8 attempts using nodes from patients with other diseases.

  2. Managing the posterior polar cataract: An update

    PubMed Central

    Vasavada, Abhay R; Vasavada, Vaishali A

    2017-01-01

    Posterior polar cataracts (PPC) have always been a challenge for cataract surgeons due to their inherently higher propensity for posterior capsule rupture. Over the years, several technical modifications have been suggested to enhance safety and reduce posterior capsule rupture rates in these polar cataracts. This review article tries to present the various techniques and strategies to published in literature to manage PPCs. It also discusses pearls for making surgery more reproducible and consistent, as well as the role of newer diagnostic and surgical technology based on the published literature on the subject. PMID:29208815

  3. Bilateral atypical nodular posterior scleritis.

    PubMed

    Kranias, G; Tyradellis, C; Krebs, T P; Augsburger, J J

    2006-01-01

    To evaluate ocular features of nodular posterior scleritis simulating choroidal melanoma. A 60-year old woman presented with blurred vision in her right eye of two weeks duration. On examination she had a mild right-globe proptosis with an episcleral nodular mass as well as a large elevated nonpigmented choroidal mass involving the nasal quadrant. A and B-scan ultrasonography showed a medium to high-reflective solid choroidal mass. MRI demonstrated a bi-convex mass in the medial aspect of the right globe with signal characteristics compatible with choroidal melanoma. Biopsy of the extraocular lesion demonstrated chronic inflammatory cell infiltrate suggestive of posterior scleritis. She responded to corticosteroid therapy. On evaluation 41 months later she was noted to have a similar choroidal mass in the left eye. The physician should be aware of the clinical manifestations and diagnostic hall marks of nodular posterior scleritis in order to differentiate this inflammatory process from choroidal melanoma.

  4. Serratus anterior and lower trapezius muscle activities during multi-joint isotonic scapular exercises and isometric contractions.

    PubMed

    Tsuruike, Masaaki; Ellenbecker, Todd S

    2015-02-01

    Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Cross-sectional study. Health Science Laboratory. A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

  5. Biomechanical consequences of a posterior root tear of the lateral meniscus: stabilizing effect of the meniscofemoral ligament.

    PubMed

    Forkel, Philipp; Herbort, Mirco; Schulze, Martin; Rosenbaum, Dieter; Kirstein, Lars; Raschke, Michael; Petersen, Wolf

    2013-05-01

    The purpose of this study was to evaluate the effects of different types of lateral meniscus root tears in terms of tibiofemoral contact stress. Ten porcine knees each underwent five different testing conditions with the menisci intact, a simulated lateral posterior root tear with and without cutting the meniscofemoral ligament and with an artificial tear of the posterior root of the medial meniscus. Biomechanical testing was performed at 30° of flexion with an axial load of 100 N. A pressure sensor (st Sensor Type S2042, Novel, Munich) was used to measure the tibiofemoral contact area and the tibiofemoral contact pressure. Data were analyzed to assess the differences in contact area and tibiofemoral peak contact pressure among the five meniscal conditions. There was no significant difference in mean contact pressure between the state with the menisci intact and an isolated posterior root tear of the lateral meniscus. In case of a root tear and a tear of the meniscofemoral ligament, the contact area decreased in comparison with the intact state of the menisci. After additional cutting of the meniscofemoral ligament, the tibiofemoral contact pressure was significantly higher in comparison with the intact state and the avulsion injury. In the medial compartment, joint compression forces were significantly increased in comparison with the intact state after cutting the posterior root of the medial meniscus (P < 0.05). The consequence of a medial meniscus root tear is well known and was verified by this analysis. The results of the present study show that the biomechanical consequences of a lateral meniscus root tear depend on the state of the meniscofemoral ligament. An increase in tibiofemoral contact pressure is only to be expected in combined injuries of the meniscus root and the meniscofemoral ligaments. Posterior lateral meniscus root tear might have a better prognosis in terms of the development of osteoarthritis when the meniscofemoral ligament is intact.

  6. [APPLICATION OF V-Y ADVANCED SENSE-REMAINED POSTERIOR TIBIAL ARTERY PERFORATOR FLAP IN REPAIRING WOUND AROUND ANKLE].

    PubMed

    Tang, Xiujun; Wang, Bo; Wei, Zairong; Wang, Dali; Han, Wenjie; Zhang, Wenduo; Li, Shujun

    2015-12-01

    OBJECTIVE To explore the feasibility and effectiveness of V-Y advanced sense-remained posterior tibial artery perforator flap in repairing wound around the ankle. METHODS Between March 2012 and January 2015, 11 patients with wounds around the ankle were treated by V-Y advanced sense-remained posterior tibial artery perforator flap. There were 6 males and 5 females with a median age of 37 years (range, 21-56 years). The causes were traffic accident injury in 3 cases, thermal injury in 2 cases, burn in 2 cases, iatrogenic wounds in 2 cases, and local contusion in 2 cases. The disease duration ranged from 1 to 3 weeks (mean, 2 weeks). Injury was located at the medial malleolus in 4 cases, at the lateral malleolus in 3 cases, and at the heel in 4 cases. All had exposure of bone, tendon, or plate. The defect area ranged from 4 cmx2 cm to 5 cmx3 cm; the area of the flap ranged from 11 cmx4 cm to 15 cmx6 cm. Necrosis of distal flap occurred in 1 case after operation; re-operation to amputate the posterior tibial artery was given and the wound was repaired by proximal skin graft. Light necrosis of distal end was observed in 2 cases, and wound healed at 3 weeks after dressing. And other flaps successfully survived, and primary healing of wounds were obtained. The patients were followed up 6-24 months (mean, 11 months). The flaps were good in color, texture, and appearance. The ankle joint had normal activity. At last follow-up, 10 cases restored fine sense, and 1 case restored protective feeling with posterior tibial artery advanced flap after amputation. V-Y advanced sense-remained posterior tibial artery perforator flap has the advantages of reliable blood supply, simple operation, good appearance, and sensory recovery. Therefore, it is an ideal method to repair wound around the ankle.

  7. Retinoic acid and Wnt/beta-catenin have complementary roles in anterior/posterior patterning embryos of the basal chordate amphioxus.

    PubMed

    Onai, Takayuki; Lin, Hsiu-Chin; Schubert, Michael; Koop, Demian; Osborne, Peter W; Alvarez, Susana; Alvarez, Rosana; Holland, Nicholas D; Holland, Linda Z

    2009-08-15

    A role for Wnt/beta-catenin signaling in axial patterning has been demonstrated in animals as basal as cnidarians, while roles in axial patterning for retinoic acid (RA) probably evolved in the deuterostomes and may be chordate-specific. In vertebrates, these two pathways interact both directly and indirectly. To investigate the evolutionary origins of interactions between these two pathways, we manipulated Wnt/beta-catenin and RA signaling in the basal chordate amphioxus during the gastrula stage, which is the RA-sensitive period for anterior/posterior (A/P) patterning. The results show that Wnt/beta-catenin and RA signaling have distinctly different roles in patterning the A/P axis of the amphioxus gastrula. Wnt/beta-catenin specifies the identity of the ends of the embryo (high Wnt = posterior; low Wnt = anterior) but not intervening positions. Thus, upregulation of Wnt/beta-catenin signaling induces ectopic expression of posterior markers at the anterior tip of the embryo. In contrast, RA specifies position along the A/P axis, but not the identity of the ends of the embryo-increased RA signaling strongly affects the domains of Hox expression along the A/P axis but has little or no effect on the expression of either anterior or posterior markers. Although the two pathways may both influence such things as specification of neuronal identity, interactions between them in A/P patterning appear to be minimal.

  8. Management of irreducible unilateral facet joint dislocations in subaxial cervical spine: two case reports and a review of the literature.

    PubMed

    Zhou, Yu; Zhou, Zhenyu; Liu, Lifeng; Cao, Xuecheng

    2018-03-21

    Skeletal and soft tissue damage are often associated with unilateral facet dislocations, which undoubtedly lead to instability of the spine and further increase difficulties in cervical reduction. This type of irreducible facet dislocation is usually accompanied with potential catastrophic consequences including neurological deficit and severe disability. Therefore, a consistent and evidence-based treatment plan is imperative. The literature regarding the management of traumatic unilateral locked cervical facet dislocations was reviewed. Two patient cases (a 30-year-old Asian man and a 25-year-old Asian woman) who suffered irreducible cervical facet dislocations were presented. These two patients received surgical treatments including posterior reduction by poking facet joints, adjacent spinous process fixation by wire rope banding, anterior plate fixation, and intervertebral fusion after the failure of skull traction and closed reduction. At the postoperative 24-month follow-up, intervertebral fusion was achieved and our patients' neurological status improved based on the American Spinal Injury Association scale, compared with their preoperative status. Unilateral facet joint dislocations of subaxial cervical spine are difficult to reduce when complicated with posterior facet fractures or ligamentous injury. Magnetic resonance imaging can be beneficial for identifying ventral and dorsal compressive lesions, as well as ligamentous or capsule rupture. The combination of posterior reduction and anterior fixation with fusion has advantages in terms of clinical safety, ease of operation, and less iatrogenic damage.

  9. Evaluation of three force-position hybrid control methods for a robot-based biological joint-testing system.

    PubMed

    Hsieh, Hong-Jung; Hu, Chih-Chung; Lu, Tung-Wu; Lu, Hsuan-Lun; Kuo, Mei-Ying; Kuo, Chien-Chung; Hsu, Horng-Chaung

    2016-06-07

    Robot-based joint-testing systems (RJTS) can be used to perform unconstrained laxity tests, measuring the stiffness of a degree of freedom (DOF) of the joint at a fixed flexion angle while allowing the other DOFs unconstrained movement. Previous studies using the force-position hybrid (FPH) control method proposed by Fujie et al. (J Biomech Eng 115(3):211-7, 1993) focused on anterior/posterior tests. Its convergence and applicability on other clinically relevant DOFs such as valgus/varus have not been demonstrated. The current s1tudy aimed to develop a 6-DOF RJTS using an industrial robot, to propose two new force-position hybrid control methods, and to evaluate the performance of the methods and FPH in controlling the RJTS for anterior/posterior and valgus/varus laxity tests of the knee joint. An RJTS was developed using an industrial 6-DOF robot with a 6-component load-cell attached at the effector. The performances of FPH and two new control methods, namely force-position alternate control (FPA) and force-position hybrid control with force-moment control (FPHFM), for unconstrained anterior/posterior and valgus/varus laxity tests were evaluated and compared with traditional constrained tests (CT) in terms of the number of control iterations, total time and the constraining forces and moments. As opposed to CT, the other three control methods successfully reduced the constraining forces and moments for both anterior/posterior and valgus/varus tests, FPHFM being the best followed in order by FPA and FPH. FPHFM had root-mean-squared constraining forces and moments of less than 2.2 N and 0.09 Nm, respectively at 0° flexion, and 2.3 N and 0.14 Nm at 30° flexion. The corresponding values for FPH were 8.5 N and 0.33 Nm, and 11.5 N and 0.45 Nm, respectively. Given the same control parameters including the compliance matrix, FPHFM and FPA reduced the constraining loads of FPH at the expense of additional control iterations, and thus increased total time, FPA

  10. Seismic velocity structure of the crust and upper mantle beneath the Texas-Gulf of Mexico margin from joint inversion of Ps and Sp receiver functions and surface wave dispersion

    NASA Astrophysics Data System (ADS)

    Agrawal, M.; Pulliam, J.; Sen, M. K.

    2013-12-01

    The seismic structure beneath Texas Gulf Coast Plain (GCP) is determined via velocity analysis of stacked common conversion point (CCP) Ps and Sp receiver functions and surface wave dispersion. The GCP is a portion of a ocean-continental transition zone, or 'passive margin', where seismic imaging of lithospheric Earth structure via passive seismic techniques has been rare. Seismic data from a temporary array of 22 broadband stations, spaced 16-20 km apart, on a ~380-km-long profile from Matagorda Island, a barrier island in the Gulf of Mexico, to Johnson City, Texas were employed to construct a coherent image of the crust and uppermost mantle. CCP stacking was applied to data from teleseismic earthquakes to enhance the signal-to-noise ratios of converted phases, such as Ps phases. An inaccurate velocity model, used for time-to-depth conversion in CCP stacking, may produce higher errors, especially in a region of substantial lateral velocity variations. An accurate velocity model is therefore essential to constructing high quality depth-domain images. To find accurate velocity P- and S-wave models, we applied a joint modeling approach that searches for best-fitting models via simulated annealing. This joint inversion approach, which we call 'multi objective optimization in seismology' (MOOS), simultaneously models Ps receiver functions, Sp receiver functions and group velocity surface wave dispersion curves after assigning relative weights for each objective function. Weights are computed from the standard deviations of the data. Statistical tools such as the posterior parameter correlation matrix and posterior probability density (PPD) function are used to evaluate the constraints that each data type places on model parameters. They allow us to identify portions of the model that are well or poorly constrained.

  11. Posttraumatic proximal migration of the first metatarsophalangeal joint sesamoids: a report of four cases.

    PubMed

    Graves, S C; Prieskorn, D; Mann, R A

    1991-10-01

    Four cases are presented with plantar plate injury to the first metatarsophalangeal (MTP) joint and proximal retraction of the sesamoids by the flexor hallucis brevis. No history of dislocation occurred in any patient, although two had associated fractures of a sesamoid bone. Clinical and radiographic aids to the diagnosis are discussed. Clinical findings included diffuse pain beneath the first MTP joint and pain with extremes of joint motion in all patients. The anterior-posterior (AP) radiographic technique was the most helpful in determining the proximal migration of the sesamoids. By taking the AP view with both feet on the cassette and by centering the beam perpendicular to it, the diagnosis of plantar plate disruption can easily be made. Initial treatment of this disorder was nonoperative using a stiff soled shoe. With conservative treatment, two of the patients returned to preinjury activities. One patient required sesamoidectomy for resistant pain, and the final patient is still unable to return to his preinjury job requiring standing and heavy lifting.

  12. Posterior corneal astigmatism in refractive lens exchange surgery.

    PubMed

    Rydström, Elin; Westin, Oscar; Koskela, Timo; Behndig, Anders

    2016-05-01

    To assess the anterior, posterior and total corneal spherical and astigmatic powers in patients undergoing refractive lens exchange (RLE) surgery. In 402 consecutive patients planned for RLE at Koskelas Eye Clinic, Luleå, Sweden, right eye data from pre- and postoperative subjective refraction, preoperative IOLMaster(®) biometry and Pentacam HR(®) measurements were collected. Postoperative Pentacam HR(®) data were collected for 54 of the patients. The spherical and astigmatic powers of the anterior and posterior corneal surfaces and for the total cornea were assessed and compared, and surgically, induced astigmatism was calculated using vector analysis. The spherical power of the anterior corneal surface was 48.18 ± 1.69D with an astigmatic power of 0.83 ± 0.54D. The corresponding values for the posterior surface were -6.05 ± 2,52D and 0.26 ± 0.15D, respectively. The total corneal spherical power calculated with ray tracing was 42.47 ± 2.89D with a 0.72 ± 0.48D astigmatic power, and the corresponding figures obtained by estimating the posterior corneal surface were 43.25 ± 1.51D (p < 0.001) with a 0.75 ± 0.49D astigmatic power (p = 0.003). In eyes with anterior astigmatism with-the-rule, the total corneal astigmatism is overestimated if the posterior corneal surface is estimated; in eyes, with against-the-rule astigmatism it is underestimated. Had the posterior corneal surface been measured in this material, 14.7% of the patients would have received a spheric instead of a toric IOL, or vice versa. Estimating the posterior corneal surface in RLE patients leads to systematic measurement errors that can be reduced by measuring the posterior surface. Such an approach can potentially increase the refractive outcome accuracy in RLE surgery. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  13. Probabilistic Simulation of Progressive Fracture in Bolted-Joint Composite Laminates

    NASA Technical Reports Server (NTRS)

    Minnetyan, L.; Singhal, S. N.; Chamis, C. C.

    1996-01-01

    This report describes computational methods to probabilistically simulate fracture in bolted composite structures. An innovative approach that is independent of stress intensity factors and fracture toughness was used to simulate progressive fracture. The effect of design variable uncertainties on structural damage was also quantified. A fast probability integrator assessed the scatter in the composite structure response before and after damage. Then the sensitivity of the response to design variables was computed. General-purpose methods, which are applicable to bolted joints in all types of structures and in all fracture processes-from damage initiation to unstable propagation and global structure collapse-were used. These methods were demonstrated for a bolted joint of a polymer matrix composite panel under edge loads. The effects of the fabrication process were included in the simulation of damage in the bolted panel. Results showed that the most effective way to reduce end displacement at fracture is to control both the load and the ply thickness. The cumulative probability for longitudinal stress in all plies was most sensitive to the load; in the 0 deg. plies it was very sensitive to ply thickness. The cumulative probability for transverse stress was most sensitive to the matrix coefficient of thermal expansion. In addition, fiber volume ratio and fiber transverse modulus both contributed significantly to the cumulative probability for the transverse stresses in all the plies.

  14. Spring-assisted posterior skull expansion without osteotomies.

    PubMed

    Arnaud, Eric; Marchac, Alexandre; Jeblaoui, Yassine; Renier, Dominique; Di Rocco, Federico

    2012-09-01

    A posterior flatness of the skull vault can be observed in infants with brachycephaly. Such posterior deformation favours the development of turricephaly which is difficult to correct. To reduce the risk of such deformation, an early posterior skull remodelling has been suggested. Translambdoid springs can be used to allow for a distraction through the patent lambdoid sutures and obtain a progressive increase of the posterior skull volume. The procedure consists in a posterior scalp elevation, the patient being on a prone position. Springs made of stainless steel wire (1.5 mm in diameter) are bent in a U-type fashion, and strategically positioned across both lambdoid sutures. No drilling is usually necessary, as the lambdoid suture can be gently forced with a subperiosteal elevator in its middle and an indentation can be created with a bony rongeur on each side of the open suture to allow for a self-retention of bayonet-shaped extremity of the spring. Careful attention is addressed to the favoured prone position during the post-operative period. After a delay of 3-6 months, the springs can be removed during a second uneventful procedure, with limited incisions, usually as a preliminary step of the subsequent frontal remodelling. The concept of spring-assisted expansion across patent sutures under 6 months of age was confirmed in our experience (19 cases). Insertion of the springs allowed for immediate distraction across the suture. A posterior remodelling of the skull could be achieved with minimal morbidity allowing to delay safely a radical anterior surgery.

  15. Traumatic synovitis in a classical guitarist: a study of joint laxity.

    PubMed Central

    Bird, H A; Wright, V

    1981-01-01

    A classical guitarist performing for at least 5 hours each day developed a traumatic synovitis at the left wrist joint that was first erroneously considered to be rheumatoid arthritis. Comparison with members of the same guitar class suggested that unusual joint laxity of the fingers and wrist, probably inherited from the patient's father, was of more importance in the aetiology of the synovitis than a wide range of movement acquired by regular practice. Hyperextension of the metacarpophalangeal joint of the left index finger, quantified by the hyperextensometer, was less marked in the guitarists than in 100 normal individuals. This may be attributed to greater muscular control of the fingers. Lateral instability in the loaded joint may be the most important factor in the aetiology of traumatic synovitis. Images PMID:7224687

  16. Experimental selective posterior semicircular canal laser deafferentation.

    PubMed

    Naguib, Maged B

    2005-05-01

    In this experimental study, we attempted to perform selective deafferentation of the posterior semicircular canal ampulla of guinea pigs using carbon dioxide laser beam. The results of this study document the efficacy of this procedure in achieving deafferentation of the posterior semicircular canal safely with regards to the other semicircular canals, the otolithic organ and the organ of hearing. Moreover, the procedure is performed with relative ease compared with other procedures previously described for selective deafferentation of the posterior semicircular canal. The clinical application of such a procedure for the treatment of intractable benign paroxysmal positional vertigo in humans is suggested.

  17. Characterization of ossification of the posterior rim of acetabulum in the developing hip and its impact on the assessment of femoroacetabular impingement.

    PubMed

    Morris, William Z; Chen, Jason Y; Cooperman, Daniel R; Liu, Raymond W

    2015-02-04

    to 36°) and acetabular overcoverage (>40°), the use of radiographs in adolescents with incompletely ossified hips may lead to misinterpretation of acetabular coverage. In patients with open triradiate cartilage, magnetic resonance imaging may be considered for the assessment of femoroacetabular impingement. The posterior rim ossification sign is a normal finding in adolescent hip development and has important implications for the proper evaluation of femoroacetabular impingement. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  18. Biomechanical testing of anterior and posterior thoracolumbar instrumentation in the cadaveric spine. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004.

    PubMed

    Eichholz, Kurt M; Hitchon, Patrick W; From, Aaron; Rubenbauer, Paige; Nakamura, Satoshi; Lim, Tae Hong; Torner, James

    2004-07-01

    Thoracolumbar burst fractures frequently require surgical intervention. Although the use of either anterior or posterior instrumentation has advantages and disadvantages, there have been few studies in which these two approaches have been compared biomechanically. Ten human cadaveric spines were subjected to subtotal L-3 corpectomy. In five spines placement of L-3 wooden strut grafts with lateral L2-4 dual rod and screw instrumentation was performed. Five other spines underwent L1-5 pedicle screw fixation. The spines were fatigued between steps of the experiment. The spines were load tested with pure moments of 1.5, 3, 4.5, and 6 Nm in the intact state and after placement of instrumentation in six degrees of freedom (flexion, extension, right and left lateral bending, and right and left axial rotation). In axial rotation posterior instrumentation significantly increased spinal rigidity compared with that of the intact state, whereas anterior instrumentation did not. Combined anterior-posterior instrumentation did not significantly increase the rigidity of the spine when compared with anterior or posterior instrumentation alone. Posterior instrumentation alone provided a greater reduction in angular rotation compared with anterior instrumentation alone in all degrees of freedom; however, statistical significance was achieved only in extension at 6 Nm. The increased rigidity provided by pedicle screw instrumentation compared with the intact state or with anterior instrumentation is due to the longer construct spanning five levels and the three-column engagement of the pedicle screws. The decision to use anterior or posterior instrumentation should be based on the clinical necessity of canal decompression and correction of angulation.

  19. In Vivo Kinematics of the Tibiotalar and Subtalar Joints in Asymptomatic Subjects: A High-Speed Dual Fluoroscopy Study.

    PubMed

    Roach, Koren E; Wang, Bibo; Kapron, Ashley L; Fiorentino, Niccolo M; Saltzman, Charles L; Bo Foreman, K; Anderson, Andrew E

    2016-09-01

    Measurements of joint kinematics are essential to understand the pathomechanics of ankle disease and the effects of treatment. Traditional motion capture techniques do not provide measurements of independent tibiotalar and subtalar joint motion. In this study, high-speed dual fluoroscopy images of ten asymptomatic adults were acquired during treadmill walking at 0.5 m/s and 1.0 m/s and a single-leg, balanced heel-rise. Three-dimensional (3D) CT models of each bone and dual fluoroscopy images were used to quantify in vivo kinematics for the tibiotalar and subtalar joints. Dynamic tibiotalar and subtalar mean joint angles often exhibited opposing trends during captured stance. During both speeds of walking, the tibiotalar joint had significantly greater dorsi/plantarflexion (D/P) angular ROM than the subtalar joint while the subtalar joint demonstrated greater inversion/eversion (In/Ev) and internal/external rotation (IR/ER) than the tibiotalar joint. During balanced heel-rise, only D/P and In/Ev were significantly different between the tibiotalar and subtalar joints. Translational ROM in the anterior/posterior (AP) direction was significantly greater in the subtalar than the tibiotalar joint during walking at 0.5 m/s. Overall, our results support the long-held belief that the tibiotalar joint is primarily responsible for D/P, while the subtalar joint facilitates In/Ev and IR/ER. However, the subtalar joint provided considerable D/P rotation, and the tibiotalar joint rotated about all three axes, which, along with translational motion, suggests that each joint undergoes complex, 3D motion.

  20. Operative techniques of anastomotic posterior urethroplasty for traumatic posterior urethral strictures.

    PubMed

    Zhou, Zhan-song; Song, Bo; Jin, Xi-yu; Xiong, En-qing; Zhang, Jia-hua

    2007-04-01

    To elucidate the details of operative technique of anastomotic posterior urethroplasty for traumatic posterior urethral strictures in attempt to offer a successful result. We reviewed the clinical data of 106 patients who had undergone anastomotic repair for posterior urethral strictures following traumatic pelvic fracture between 1979 and 2004. Patients'age ranged from 8 to 53 years (mean 27 years). Surgical repair was performed via perinea in 72 patients, modified transperineal repair in 5 and perineoabdominal repair in 29. Follow-up ranged from 1 to 23 years (mean 8 years). Among the 77 patients treated by perineal approaches, 69 (95.8%) were successfully repaired and 27 out of the 29 patients (93.1%) who were repaired by perineoabdominal protocols were successful. The successful results have sustained as long as 23 years in some cases. Urinary incontinence did not happen in any patients while impotence occurred as a result of the anastomotic surgery. Three important skills or principles will ensure a successful outcome, namely complete excision of scar tissues, a completely normal mucosa ready for anastomosis at both ends of the urethra, and a tension-free anastomosis. When the urethral stricture is below 2.5 cm long, restoration of urethral continuity can be accomplished by a perineal procedure. If the stricture is over 2.5 cm long, a modified perineal or transpubic perineoabdominal procedure should be used. In the presence of a competent bladder neck, anastomotic surgery does not result in urinary incontinence. Impotence is usually related to the original trauma and rarely (5.7%) to urethroplasty.

  1. An empirical investigation into the role of subjective prior probability in searching for potentially missing items

    PubMed Central

    Fanshawe, T. R.

    2015-01-01

    There are many examples from the scientific literature of visual search tasks in which the length, scope and success rate of the search have been shown to vary according to the searcher's expectations of whether the search target is likely to be present. This phenomenon has major practical implications, for instance in cancer screening, when the prevalence of the condition is low and the consequences of a missed disease diagnosis are severe. We consider this problem from an empirical Bayesian perspective to explain how the effect of a low prior probability, subjectively assessed by the searcher, might impact on the extent of the search. We show how the searcher's posterior probability that the target is present depends on the prior probability and the proportion of possible target locations already searched, and also consider the implications of imperfect search, when the probability of false-positive and false-negative decisions is non-zero. The theoretical results are applied to two studies of radiologists' visual assessment of pulmonary lesions on chest radiographs. Further application areas in diagnostic medicine and airport security are also discussed. PMID:26587267

  2. A Comprehensive Specimen-Specific Multiscale Data Set for Anatomical and Mechanical Characterization of the Tibiofemoral Joint

    PubMed Central

    Chokhandre, Snehal; Colbrunn, Robb; Bennetts, Craig; Erdemir, Ahmet

    2015-01-01

    Understanding of tibiofemoral joint mechanics at multiple spatial scales is essential for developing effective preventive measures and treatments for both pathology and injury management. Currently, there is a distinct lack of specimen-specific biomechanical data at multiple spatial scales, e.g., joint, tissue, and cell scales. Comprehensive multiscale data may improve the understanding of the relationship between biomechanical and anatomical markers across various scales. Furthermore, specimen-specific multiscale data for the tibiofemoral joint may assist development and validation of specimen-specific computational models that may be useful for more thorough analyses of the biomechanical behavior of the joint. This study describes an aggregation of procedures for acquisition of multiscale anatomical and biomechanical data for the tibiofemoral joint. Magnetic resonance imaging was used to acquire anatomical morphology at the joint scale. A robotic testing system was used to quantify joint level biomechanical response under various loading scenarios. Tissue level material properties were obtained from the same specimen for the femoral and tibial articular cartilage, medial and lateral menisci, anterior and posterior cruciate ligaments, and medial and lateral collateral ligaments. Histology data were also obtained for all tissue types to measure specimen-specific cell scale information, e.g., cellular distribution. This study is the first of its kind to establish a comprehensive multiscale data set for a musculoskeletal joint and the presented data collection approach can be used as a general template to guide acquisition of specimen-specific comprehensive multiscale data for musculoskeletal joints. PMID:26381404

  3. Posterior fossa tumor

    MedlinePlus

    ... Most tumors of the posterior fossa are primary brain cancers. They start in the brain, rather than spreading from somewhere else in the ... nausea, vomiting, or vision changes. Alternative Names ... JF, Hollander AB, Alonso-Basanta M, et al. Cancer of the central nervous system. In: Niederhuber JE, ...

  4. High-resolution ultrasonic imaging of the posterior segment.

    PubMed

    Coleman, D Jackson; Silverman, Ronald H; Chabi, Almira; Rondeau, Mark J; Shung, K Kirk; Cannata, Jon; Lincoff, Harvey

    2004-07-01

    Conventional ophthalmic ultrasonography is performed using 10-megahertz (MHz) transducers. Our aim was to explore the use of higher frequency ultrasound to provide improved resolution of the posterior pole. Prospective case series. One normal subject and 5 subjects with pathologies affecting the posterior coats, including nevii, small melanomas, and macular hole. We modeled the frequency-dependent attenuation of ultrasound across the eye to develop an understanding of the range of frequencies that might be practically applied for imaging of the posterior pole. We compared images of the posterior coats made at 10, 15, and 20 MHz, and 20-MHz ultrasound images of pathologies with 10-MHz ultrasound and optical coherence tomography (OCT). Ability to resolve normal and pathologic structures affecting posterior coats of the eye. Modeling showed that frequencies of 20 to 25 MHz might be used for posterior pole imaging. Twenty-megahertz images allowed differentiation of the retina, choroid, and sclera. In addition, at 20 MHz the retina showed banding patterns suggesting an internal structure comparable in many respects to that seen in OCT and histology. Images of ocular pathology provided much improved detail relative to 10-MHz images and deeper penetration than OCT. Twenty-megahertz ultrasound can be practically employed for imaging of the posterior pole of the eye, providing a 2-fold improvement in resolution relative to conventional 10-MHz instruments. Although not providing the resolution of OCT, ultrasound can be used in the presence of optical opacities and allows evaluation of deeper tissue structures.

  5. High hydrostatic pressures in traumatic joints require elevated synovial capillary pressure probably associated with arteriolar vasodilatation.

    PubMed

    Ahlqvist, J; Harilainen, A; Aalto, K; Sarna, S; Lalla, M; Osterlund, K

    1994-11-01

    Three out of the four Starling pressures were determined at arthroscopy of traumatic effusions of the knee. The range of the joint fluid hydrostatic pressure Pjoint was 5-83 cmH2O (0.5-8.1 kPa, 4-61 mmHg), that of the colloid osmotic pressure difference COPplasma-COPjoint 0-21.7 cmH2O. In 11 of 15 cases the sum Pjoint+COP difference exceeded 32.6 cmH2O (3.19 kPa, 24 mmHg), a high estimate of average capillary pressure at the level of the heart. The number of 'exceeding' cases was 8/15 if only 80% of the COP difference was considered effective. Pjoint and the COP difference oppose filtration of fluid from plasma into joints, indicating that mean capillary pressure, the only Starling pressure not determined, was elevated unless the effusions were being resorbed back into the blood. The findings can be explained by tamponade compensated by arteriolar vasodilatation, suspected to be metabolically mediated.

  6. The Posterior Cervical Lymph Node in Toxoplasmosis

    PubMed Central

    Gray, George F.; Kimball, Anne C.; Kean, B. H.

    1972-01-01

    Posterior cervical node enlargement is characteristic of clinical toxoplasmosis in adults. Lymph node biopsies from 37 patients, who were tested for toxoplasmosis by serologic and isolation studies, were examined. A characteristic pattern of sinus histiocytosis was seen in 17 of 18 posterior cervical nodes and in only 1 of 4 lymph nodes from other sites from patients with toxoplasmosis. The characteristic pattern was not seen in posterior cervical nodes or in lymph nodes from other sites from patients with other diseases. Lymphoma obscured the characteristic changes of toxoplasmosis in the posterior cervical nodes and other nodes of 5 patients with these coexisting diseases. Organisms were seen in tissue sections in only 2 instances. T gondii was isolated from mice in 14 of 17 attempts using nodes from patients with toxoplasmosis, but from none of 8 attempts using nodes from patients with other diseases. ImagesFig 3Fig 4Fig 1Fig 2 PMID:4634739

  7. The maximum entropy method of moments and Bayesian probability theory

    NASA Astrophysics Data System (ADS)

    Bretthorst, G. Larry

    2013-08-01

    The problem of density estimation occurs in many disciplines. For example, in MRI it is often necessary to classify the types of tissues in an image. To perform this classification one must first identify the characteristics of the tissues to be classified. These characteristics might be the intensity of a T1 weighted image and in MRI many other types of characteristic weightings (classifiers) may be generated. In a given tissue type there is no single intensity that characterizes the tissue, rather there is a distribution of intensities. Often this distributions can be characterized by a Gaussian, but just as often it is much more complicated. Either way, estimating the distribution of intensities is an inference problem. In the case of a Gaussian distribution, one must estimate the mean and standard deviation. However, in the Non-Gaussian case the shape of the density function itself must be inferred. Three common techniques for estimating density functions are binned histograms [1, 2], kernel density estimation [3, 4], and the maximum entropy method of moments [5, 6]. In the introduction, the maximum entropy method of moments will be reviewed. Some of its problems and conditions under which it fails will be discussed. Then in later sections, the functional form of the maximum entropy method of moments probability distribution will be incorporated into Bayesian probability theory. It will be shown that Bayesian probability theory solves all of the problems with the maximum entropy method of moments. One gets posterior probabilities for the Lagrange multipliers, and, finally, one can put error bars on the resulting estimated density function.

  8. Surgical treatment of acute acromioclavicular joint dislocations: hook plate versus minimally invasive reconstruction.

    PubMed

    Metzlaff, S; Rosslenbroich, S; Forkel, P H; Schliemann, B; Arshad, H; Raschke, M; Petersen, W

    2016-06-01

    This study was performed to compare the clinical results of a minimally invasive technique for acute acromioclavicular (AC) joint dislocation repair with the traditional hook plate fixation. Forty-four patients with an acute (within 2 weeks after trauma) complete AC joint separation (35 male, nine female; median age 36.2 years, range 18-56) underwent surgical repair with either a minimally invasive AC joint repair or a conventional hook plate. Functional outcome was evaluated using the Constant-Murley Score (CMS), the TAFT score and the AC joint instability score (ACJI). Radiographic evaluation was performed with bilateral anterior-posterior (a.p.) stress and Alexander views. All patients were available after a median follow-up of 32 months (range 24-51). There were no significant differences in the mean CMS, Taft score and the ACJI between the two groups. The radiological assessment revealed no significant difference in the coracoclavicular distance. In both groups, a slight loss of reduction was observed. Periarticular ossification was seen in 11 patients of the minimally invasive AC joint repair and eight patients of the hook plate group but this did not affect the final outcome. Hook plates were removed after a median interval of 11.9 weeks (range 10-13). Good clinical results can be achieved with both minimally invasive AC joint repair and hook plate fixation. However, in the hook plate group a second operation is mandatory for plate removal. III.

  9. The correlation between movement of the center of mass and the kinematics of the spine, pelvis, and hip joints during body rotation.

    PubMed

    Wada, Osamu; Tateuchi, Hiroshige; Ichihashi, Noriaki

    2014-01-01

    Body rotation is associated with many activities. The concomitant movement of the center of mass (COM) is essential for effective body rotation. This movement is considered to be influenced by kinematic changes in the spine, pelvis, and hip joints. However, there is no research on the association between COM movement and kinematic changes during body rotation. We aimed to investigate the association between COM movement and the kinematics of the spine, pelvis, and hip joints during body rotation in standing. Twenty-four healthy men were included in the study. COM movement during active body rotation in a standing position was measured. We evaluated pelvic shift and changes in the angles of the spine, pelvis, and hip joints. We calculated the Pearson correlation coefficients to analyze the relationship between COM movement and kinematic changes in the spine, pelvis, and hip joints. There were significant correlations between lateral COM movement to the rotational side and pelvic shift to the rotational side, and between posterior COM movement and pelvic shift to the posterior side. In addition, lateral COM movement to the rotational side showed significant and negative correlation with spinal flexion and was significantly and positively correlated with the change in anterior pelvic tilt. Clinicians need to take particular note of both spinal and pelvic motion in the sagittal plane, as well as the pelvic shift, to speculate COM movement during body rotation in standing. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Joint genome-wide prediction in several populations accounting for randomness of genotypes: A hierarchical Bayes approach. I: Multivariate Gaussian priors for marker effects and derivation of the joint probability mass function of genotypes.

    PubMed

    Martínez, Carlos Alberto; Khare, Kshitij; Banerjee, Arunava; Elzo, Mauricio A

    2017-03-21

    It is important to consider heterogeneity of marker effects and allelic frequencies in across population genome-wide prediction studies. Moreover, all regression models used in genome-wide prediction overlook randomness of genotypes. In this study, a family of hierarchical Bayesian models to perform across population genome-wide prediction modeling genotypes as random variables and allowing population-specific effects for each marker was developed. Models shared a common structure and differed in the priors used and the assumption about residual variances (homogeneous or heterogeneous). Randomness of genotypes was accounted for by deriving the joint probability mass function of marker genotypes conditional on allelic frequencies and pedigree information. As a consequence, these models incorporated kinship and genotypic information that not only permitted to account for heterogeneity of allelic frequencies, but also to include individuals with missing genotypes at some or all loci without the need for previous imputation. This was possible because the non-observed fraction of the design matrix was treated as an unknown model parameter. For each model, a simpler version ignoring population structure, but still accounting for randomness of genotypes was proposed. Implementation of these models and computation of some criteria for model comparison were illustrated using two simulated datasets. Theoretical and computational issues along with possible applications, extensions and refinements were discussed. Some features of the models developed in this study make them promising for genome-wide prediction, the use of information contained in the probability distribution of genotypes is perhaps the most appealing. Further studies to assess the performance of the models proposed here and also to compare them with conventional models used in genome-wide prediction are needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Analysis of Knee Joint Line Obliquity after High Tibial Osteotomy.

    PubMed

    Oh, Kwang-Jun; Ko, Young Bong; Bae, Ji Hoon; Yoon, Suk Tae; Kim, Jae Gyoon

    2016-11-01

    The aim of this study was to evaluate which lower extremity alignment (knee and ankle joint) parameters affect knee joint line obliquity (KJLO) in the coronal plane after open wedge high tibial osteotomy (OWHTO). Overall, 69 knees of patients that underwent OWHTO were evaluated using radiographs obtained preoperatively and from 6 weeks to 3 months postoperatively. We measured multiple parameters of knee and ankle joint alignment (hip-knee-ankle angle [HKA], joint line height [JLH], posterior tibial slope [PS], femoral condyle-tibial plateau angle [FCTP], medial proximal tibial angle [MPTA], mechanical lateral distal femoral angle [mLDFA], KJLO, talar tilt angle [TTA], ankle joint obliquity [AJO], and the lateral distal tibial ground surface angle [LDTGA]; preoperative [-pre], postoperative [-post], and the difference between -pre and -post values [-Δ]). We categorized patients into two groups according to the KJLO-post value (the normal group [within ± 4 degrees, 56 knees] and the abnormal group [greater than ± 4 degrees, 13 knees]), and compared their -pre parameters. Multiple logistic regression analysis was used to examine the contribution of the -pre parameters to abnormal KJLO-post. The mean HKA-Δ (-9.4 ± 4.7 degrees) was larger than the mean KJLO-Δ (-2.1 ± 3.2 degrees). The knee joint alignment parameters (the HKA-pre, FCTP-pre) differed significantly between the two groups ( p  < 0.05). In addition, the HKA-pre (odds ratio [OR] = 1.27, p  = 0.006) and FCTP-pre (OR = 2.13, p  = 0.006) were significant predictors of abnormal KJLO-post. However, -pre ankle joint parameters (TTA, AJO, and LDTGA) did not differ significantly between the two groups and were not significantly associated with the abnormal KJLO-post. The -pre knee joint alignment and knee joint convergence angle evaluated by HKA-pre and FCTP-pre angle, respectively, were significant predictors of abnormal KJLO after OWHTO. However, -pre ankle joint

  12. Referred pain location depends on the affected section of the sacroiliac joint.

    PubMed

    Kurosawa, Daisuke; Murakami, Eiichi; Aizawa, Toshimi

    2015-03-01

    Pain referred from the sacroiliac joint (SIJ) may originate in the joint's posterior ligamentous region. The site of referred pain may depend on which SIJ section is affected. This study aimed to determine the exact origin of pain referred from four SIJ sections. The study included 50 patients with SIJ dysfunction, confirmed by more than 70 % pain relief after periarticular injection of local anesthetic into the SIJ. The posterior SIJ was divided into four sections-upper, middle, lower, and other (cranial portion of the ilium outside the SIJ)-designated sections 1, 2, 3, and 0, respectively. We then inserted a needle into the periarticular SIJ under fluoroscopy. After the patient identified the area(s) in which the needle insertion produced referred pain, we injected a mixture of 2 % lidocaine and contrast medium into the corresponding SIJ section. Referred pain from SIJ section 0 was mainly located in the upper buttock along the iliac crest; pain from section 1, around the posterosuperior iliac spine; pain from section 2, in the middle buttock area; pain from section 3, in the lower buttock. In all, 22 (44.0 %) patients complained of groin pain, which was slightly relieved by lidocaine injection into SIJ sections 1 and 0. Dysfunctional upper sections of the SIJ are associated with pain in the upper buttock and lower sections with pain in the lower buttock. Groin pain might be referred from the upper SIJ sections.

  13. Spinal hemianesthesia: Unilateral and posterior

    PubMed Central

    Imbelloni, Luiz Eduardo

    2014-01-01

    The injection of a non-isobaric local anesthetic should induce a unilateral spinal anesthesia in patients in a lateral decubitus position. The posterior spinal hemianesthesia only be obtained with hypobaric solutions injected in the jackknife position. The most important factors to be considered when performing a spinal hemianesthesia are: type and gauge of the needle, density of the local anesthetic relative to the CSF, position of the patient, speed of administration of the solution, time of stay in position, and dose/concentration/volume of the anesthetic solution. The distance between the spinal roots on the right-left sides and anterior-posterior is, approximately, 10-15 mm. This distance allows performing unilateral spinal anesthesia or posterior spinal anesthesia. The great advantage of obtaining spinal hemianesthesia is the reduction of cardiovascular changes. Likewise, both the dorsal and unilateral sensory block predominates in relation to the motor block. Because of the numerous advantages of producing spinal hemianesthesia, anesthesiologists should apply this technique more often. This review considers the factors which are relevant, plausible and proven to obtain spinal hemianesthesia. PMID:25886320

  14. Technology-Enhanced Interactive Teaching of Marginal, Joint and Conditional Probabilities: The Special Case of Bivariate Normal Distribution

    ERIC Educational Resources Information Center

    Dinov, Ivo D.; Kamino, Scott; Bhakhrani, Bilal; Christou, Nicolas

    2013-01-01

    Data analysis requires subtle probability reasoning to answer questions like "What is the chance of event A occurring, given that event B was observed?" This generic question arises in discussions of many intriguing scientific questions such as "What is the probability that an adolescent weighs between 120 and 140 pounds given that…

  15. Safe Zone of Posterior Screw Insertion for Talar Neck Fractures on 3-Dimensional Reconstruction Model.

    PubMed

    Wu, Jian-Qun; Ma, Sheng-Hui; Liu, Song; Qin, Cheng-He; Jin, Dan; Yu, Bin

    2017-02-01

    To investigate the optimal posterior screw placement and the geometry of safe zones for screw insertion in the talar neck. Computed tomography data for 15 normal feet were imported into Mimics 10.01 software for 3-dimensional reconstruction; 4.0-mm-diameter screws were simulated from the lateral tubercle of the posterior process of the talus to the talar head. The range of screw paths trajectories and screw lengths at nine locations that did not breach the cortex of the talus were evaluated. In addition, the farthest (point a) and nearest point (point b) of the safe zone to the subtalar joint at each location, the anteversion angle (angle A), which is parallel to the sagittal plane, and the horizontal angle (angle B), which is perpendicular to the sagittal plane, were measured. The safe zone was mainly between the 30% location and the 60% location; the width of each safe zone was 13.6° ± 1.4°; the maximum height of each safe zone was 7.8° ± 1.2°. The height of the safe zone was lowest at the 30% location (4.5°) and highest at the 50% location (7.3°). The mixed safe zone of all tali was between the 50% location and the 60% location. When a screw was inserted at point a, the safe entry distance (screw length) ranged from 48.8 to 49.5 mm, and when inserted to point b, the distance ranged from 48.2 to 48.9 mm. And inserting a 48.7 mm screw, 5.6° laterally and 7.4° superiorly, from the lateral tubercle of the posterior process of the talus towards the talar head is safest. The safe zone of posterior screw fixation have been defined applying to most talus, assuming the fractures are well reduced, this may strengthen the stability, shorten the operation time and reduce the incidence of surgical complications. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

  16. Accuracy of intra-articular injection of the glenohumeral joint: a modified anterior approach.

    PubMed

    Jo, Chris Hyunchul; Shin, Young Ho; Shin, Ji Sun

    2011-10-01

    This study examined the accuracy of our modified anterior approach to the glenohumeral joint using arthrography. Two hundred fifty-six consecutive patients with adhesive capsulitis received the glenohumeral joint injection: a mixture of 1 mL of 40 mg of triamcinolone hexacetonide, 2 mL of 2% lidocaine, 3 mL of contrast medium (Ioxitalamate), and 4 mL of normal saline solution, for a total of 10 mL, through a modified anterior approach. Anteroposterior, lateral, and axial arthrography after each injection was performed to determine the accuracy and patterns of the injection. The injection was judged to be successful if some of the contrast medium was placed within the joint. There were 78 male and 178 female patients, and the mean age was 54 years (range, 28 to 87 years). In 232 of the 256 patients (90.6%), the injection was deemed to have reached the glenohumeral joint, and these cases were considered successful. Among these patients, the contrast medium was shown only in the joint in 189 (73.8%), whereas in 43 (16.8%) it was shown both in and out of the joint. Of the 24 misguided injections, 15 (5.9%) had anterior placement, 6 (2.3%) had posterior placement, and 2 (0.8%) had superior placement, whereas the material was located in all portions outside the joint in 1 (0.4%). This study showed that our modified anterior approach had an accuracy greater than 90% for the intra-articular injection of the glenohumeral joint without radiographic guidance. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  17. An unusual and spectacular case of spindle cell lipoma of the posterior neck invading the spinal cervical canal and posterior cranial fossa.

    PubMed

    Petit, Damien; Menei, Philippe; Fournier, Henri-Dominique

    2011-11-01

    The authors describe the first case of spindle cell lipoma of the posterior neck invading the upper cervical spinal canal and the posterior cranial fossa. Spindle cell lipoma is an extremely rare variant of benign lipoma. It usually occurs as a solitary subcutaneous well-circumscribed lesion in the posterior neck or shoulders of adult men. Local aggressiveness is unusual. This 61-year-old man presented with an increased left cerebellar syndrome and headaches. He also had a posterior neck tumefaction, which had been known about for a long time. Computed tomography and MR imaging studies revealed a voluminous mass extending to the upper cervical canal and posterior cranial fossa and eroding the neighboring bones. The lesion was well delimited, and contrast enhancement was intense and heterogeneous. The tumor, which had initially developed under the muscles of the posterior neck, was totally resected. Histological assessment revealed numerous fat cells with spindle cells secreting collagen. The large size of the tumor and the submuscular location, bone erosion, and compression of the CNS were unusual in this rare subtype of benign adipose tumor. Its presentation could simulate a sarcoma.

  18. Movement of the sacroiliac joint during the Active Straight Leg Raise test in patients with long-lasting severe sacroiliac joint pain.

    PubMed

    Kibsgård, Thomas J; Röhrl, Stephan M; Røise, Olav; Sturesson, Bengt; Stuge, Britt

    2017-08-01

    The Active Straight Leg Raise is a functional test used in the assessment of pelvic girdle pain, and has shown to have good validity, reliability and responsiveness. The Active Straight Leg Raise is considered to examine the patients' ability to transfer load through the pelvis. It has been hypothesized that patients with pelvic girdle pain lack the ability to stabilize the pelvic girdle, probably due to instability or increased movement of the sacroiliac joint. This study examines the movement of the sacroiliac joints during the Active Straight Leg Raise in patients with pelvic girdle pain. Tantalum markers were inserted in the dorsal sacrum and ilium of 12 patients with long-lasting pelvic girdle pain scheduled for sacroiliac joint fusion surgery. Two to three weeks later movement of the sacroiliac joints during the Active Straight Leg Raise was measured with radiostereometric analysis. Small movements were detected. There was larger movement of the sacroiliac joint of the rested leg's sacroiliac joint compared to the lifted leg's side. A mean backward rotation of 0.8° and inward tilt of 0.3° were seen in the rested leg's sacroiliac joint. The movements of the sacroiliac joints during the Active Straight Leg Raise are small. There was a small backward rotation of the innominate bone relative to sacrum on the rested leg's side. Our findings contradict an earlier understanding that a forward rotation of the lifted leg's innominate occur while performing the Active Straight Leg Raise. Copyright © 2017. Published by Elsevier Ltd.

  19. Masticatory muscle and temporomandibular joint pain in Croatian war veterans with posttraumatic stress disorder.

    PubMed

    Uhac, Ivone; Tariba, Petra; Kovac, Zoran; Simonić-Kocijan, Suncana; Lajnert, Vlatka; Mesić, Vesna Fugosić; Kuis, Davor; Braut, Vedrana

    2011-12-01

    The aim of this study was to investigate the prevalence and intensity of masticatory muscle and temporomandibular joint (TMJ) pain in Croatian war veterans with posttraumatic stress disorder (PTSD). The examined group consisted of 100 Croatian war veterans, in whom PTSD had previously been diagnosed. Patients were compared with 92 subjects who had not taken part in the war and in whom PTSD was excluded by psychiatric examination. The clinical examination consisted of palpation of the masticatory muscles, the prominent neck musculature, and TMJ. The examination technique used and the definition of items were previously tested for reliability and validity. 93% of the subjects with PTSD had masticatory muscle tenderness compared to 45.65% of the subjects in the control group (chi2 = 51.46, p < 0.0001). The most frequent painful location in the subjects with PTSD was the left lateral pterygoid site in 88%, and in subjects of the control group the right lateral pterygoid site in 28.26% of cases. The most painful location in the PTSD group was the left lateral pterygoid site in 72%, and in the control group the left posterior digastric in 4.35% of cases. 58% of the subjects with PTSD had TMJ tenderness compared to 3.26% of subjects in the control group (chi2 = 66.23, p < 0.0001). The most frequent painful location of TMJ in both groups was the left posterior capsule; in the PTSD group 38% and in subjects in the control group 2.17% of cases. The most painful location was the left posterior capsule in 28% of subjects with PTSD, while not one subject in the control group reported severe painful sensitivity. The very high frequency and intensity of pain in subjects with PTSD confirms the effect of stress on muscle and joint sensitivity, i.e. perception of pain.

  20. Optimizing tooth form with direct posterior composite restorations.

    PubMed

    Raghu, Ramya; Srinivasan, Raghu

    2011-10-01

    Advances in material sciences and technology have provided today's clinicians the strategies to transform the mechanistic approach of operative dentistry into a biologic philosophy. In the last three decades, composite resins have gone from being just an esthetically pleasing way of restoring Class III and Class IV cavities to become the universal material for both anterior and posterior situations as they closely mimic the natural esthetics while restoring the form of the human dentition. In order to enhance their success, clinicians have to rethink their protocol instead of applying the same restorative concepts and principles practiced with metallic restorations. Paralleling the evolution of posterior composite resin materials, cavity designs, restorative techniques and armamentarium have also developed rapidly to successfully employ composite resins in Class II situations. Most of the earlier problems with posterior composites such as poor wear resistance, polymerization shrinkage, postoperative sensitivity, predictable bonding to dentin, etc., have been overcome to a major extent. However, the clinically relevant aspect of achieving tight contacts in Class II situations has challenged clinicians the most. This paper reviews the evolution of techniques and recent developments in achieving predictable contacts with posterior composites. A Medline search was performed for articles on "direct posterior composite contacts." The keywords used were "contacts and contours of posterior composites." The reference list of each article was manually checked for additional articles of relevance.

  1. The neural correlates of subjective utility of monetary outcome and probability weight in economic and in motor decision under risk

    PubMed Central

    Wu, Shih-Wei; Delgado, Mauricio R.; Maloney, Laurence T.

    2011-01-01

    In decision under risk, people choose between lotteries that contain a list of potential outcomes paired with their probabilities of occurrence. We previously developed a method for translating such lotteries to mathematically equivalent motor lotteries. The probability of each outcome in a motor lottery is determined by the subject’s noise in executing a movement. In this study, we used functional magnetic resonance imaging in humans to compare the neural correlates of monetary outcome and probability in classical lottery tasks where information about probability was explicitly communicated to the subjects and in mathematically equivalent motor lottery tasks where probability was implicit in the subjects’ own motor noise. We found that activity in the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC) quantitatively represent the subjective utility of monetary outcome in both tasks. For probability, we found that the mPFC significantly tracked the distortion of such information in both tasks. Specifically, activity in mPFC represents probability information but not the physical properties of the stimuli correlated with this information. Together, the results demonstrate that mPFC represents probability from two distinct forms of decision under risk. PMID:21677166

  2. The neural correlates of subjective utility of monetary outcome and probability weight in economic and in motor decision under risk.

    PubMed

    Wu, Shih-Wei; Delgado, Mauricio R; Maloney, Laurence T

    2011-06-15

    In decision under risk, people choose between lotteries that contain a list of potential outcomes paired with their probabilities of occurrence. We previously developed a method for translating such lotteries to mathematically equivalent "motor lotteries." The probability of each outcome in a motor lottery is determined by the subject's noise in executing a movement. In this study, we used functional magnetic resonance imaging in humans to compare the neural correlates of monetary outcome and probability in classical lottery tasks in which information about probability was explicitly communicated to the subjects and in mathematically equivalent motor lottery tasks in which probability was implicit in the subjects' own motor noise. We found that activity in the medial prefrontal cortex (mPFC) and the posterior cingulate cortex quantitatively represent the subjective utility of monetary outcome in both tasks. For probability, we found that the mPFC significantly tracked the distortion of such information in both tasks. Specifically, activity in mPFC represents probability information but not the physical properties of the stimuli correlated with this information. Together, the results demonstrate that mPFC represents probability from two distinct forms of decision under risk.

  3. Analytic posteriors for Pearson's correlation coefficient.

    PubMed

    Ly, Alexander; Marsman, Maarten; Wagenmakers, Eric-Jan

    2018-02-01

    Pearson's correlation is one of the most common measures of linear dependence. Recently, Bernardo (11th International Workshop on Objective Bayes Methodology, 2015) introduced a flexible class of priors to study this measure in a Bayesian setting. For this large class of priors, we show that the (marginal) posterior for Pearson's correlation coefficient and all of the posterior moments are analytic. Our results are available in the open-source software package JASP.

  4. Three-Dimensional Geometric Nonlinear Contact Stress Analysis of Riveted Joints

    NASA Technical Reports Server (NTRS)

    Shivakumar, Kunigal N.; Ramanujapuram, Vivek

    1998-01-01

    The problems associated with fatigue were brought into the forefront of research by the explosive decompression and structural failure of the Aloha Airlines Flight 243 in 1988. The structural failure of this airplane has been attributed to debonding and multiple cracking along the longitudinal lap splice riveted joint in the fuselage. This crash created what may be termed as a minor "Structural Integrity Revolution" in the commercial transport industry. Major steps have been taken by the manufacturers, operators and authorities to improve the structural airworthiness of the aging fleet of airplanes. Notwithstanding, this considerable effort there are still outstanding issues and concerns related to the formulation of Widespread Fatigue Damage which is believed to have been a contributing factor in the probable cause of the Aloha accident. The lesson from this accident was that Multiple-Site Damage (MSD) in "aging" aircraft can lead to extensive aircraft damage. A strong candidate in which MSD is highly probable to occur is the riveted lap joint.

  5. Mechanical role of the posterior column components in the cervical spine.

    PubMed

    Hartman, Robert A; Tisherman, Robert E; Wang, Cheng; Bell, Kevin M; Lee, Joon Y; Sowa, Gwendolyn A; Kang, James D

    2016-07-01

    To quantify the mechanical role of posterior column components in human cervical spine segments. Twelve C6-7 segments were subjected to resection of (1) suprasinous/interspinous ligaments (SSL/ISL), (2) ligamenta flavum (LF), (3) facet capsules, and (4) facets. A robot-based testing system performed repeated flexibility testing of flexion-extension (FE), axial rotation (AR), and lateral bending (LB) to 2.5Nm and replayed kinematics from intact flexibility tests for each state. Range-of-motion, stiffness, moment resistance and resultant forces were calculated. The LF contributes largely to moment resistance, particularly in flexion. Facet joints were primary contributors to AR and LB mechanics. Moment/force responses were more sensitive and precise than kinematic outcomes. The LF is mechanically important in the cervical spine; its injury could negatively impact load distribution. Damage to facets in a flexion injury could lead to AR or LB hypermobility. Quantifying the contribution of spinal structures to moment resistance is a sensitive, precise process for characterizing structural mechanics.

  6. Evaluation of the outcomes after posterior urethroplasty.

    PubMed

    Liberman, Daniel; Pagliara, Travis J; Pisansky, Andrew; Elliott, Sean P

    2015-03-01

    Posterior urethral injury is a clinically significant complication of pelvic fractures. The management is complicated by the associated organ injuries, distortion of the pelvic anatomy and the ensuing fibrosis that occurs with urethral injury. We report a review of the outcomes after posterior urethroplasty in the context of pelvic fracture urethral injury.

  7. Lower extremity joint loads in habitual rearfoot and mid/forefoot strike runners with normal and shortened stride lengths.

    PubMed

    Boyer, Elizabeth R; Derrick, Timothy R

    2018-03-01

    Our purpose was to compare joint loads between habitual rearfoot (hRF) and habitual mid/forefoot strikers (hFF), rearfoot (RFS) and mid/forefoot strike (FFS) patterns, and shorter stride lengths (SLs). Thirty-eight hRF and hFF ran at their normal SL, 5% and 10% shorter, as well as with the opposite foot strike. Three-dimensional ankle, knee, patellofemoral (PF) and hip contact forces were calculated. Nearly all contact forces decreased with a shorter SL (1.2-14.9% relative to preferred SL). In general, hRF had higher PF (hRF-RFS: 10.8 ± 1.4, hFF-FFS: 9.9 ± 2.0 BWs) and hip loads (axial hRF-RFS: -9.9 ± 0.9, hFF-FFS: -9.6 ± 1.0 BWs) than hFF. Many loads were similar between foot strike styles for the two groups, including axial and lateral hip, PF, posterior knee and shear ankle contact forces. Lateral knee and posterior hip contact forces were greater for RFS, and axial ankle and knee contact forces were greater for FFS. The tibia may be under greater loading with a FFS because of these greater axial forces. Summarising, a particular foot strike style does not universally decrease joint contact forces. However, shortening one's SL 10% decreased nearly all lower extremity contact forces, so it may hold potential to decrease overuse injuries associated with excessive joint loads.

  8. Frequency and determinants for hemorrhagic transformation of posterior cerebral stroke : Posterior ischemic stroke and hemorrhagic transformation.

    PubMed

    Valentino, Francesca; Gentile, Luana; Terruso, Valeria; Mastrilli, Sergio; Aridon, Paolo; Ragonese, Paolo; Sarno, Caterina; Savettieri, Giovanni; D'Amelio, Marco

    2017-11-13

    hemorrhagic transformation is a threatening ischemic stroke complication. Frequency of hemorrhagic transformation differs greatly among studies, and its risk factors have been usually studied in patients with anterior ischemic stroke who received thrombolytic therapy. We evaluated, in a hospital-based series of patients with posterior ischemic stroke not treated with thrombolysis, frequency and risk factors of hemorrhagic transformation. Patients with posterior circulation stroke were seen in our Department during the period January 2004 to December 2009. Demographic and clinical information were collected. We estimated risk for spontaneous hemorrhagic transformation by means of uni- and multivariate logistic regression analyses. 119 consecutive patients were included (73 males, 61.3%). Hemorrhagic transformation was observed in 7 patients (5.9%). Only clinical worsening was significantly associated with hemorrhagic transformation (OR 6.8, 95% CI 1.3-34.5). Our findings indicate that patients with posterior have a low risk of spontaneous hemorrhagic transformation, suggesting that these patients might have greater advantage from intravenous thrombolysis.

  9. A clinical sign to detect root avulsions of the posterior horn of the medial meniscus.

    PubMed

    Seil, Romain; Dück, Klaus; Pape, Dietrich

    2011-12-01

    The goal of the present report was to describe a new clinical sign to make a clinical diagnosis of meniscal extrusion related to medial meniscal root avulsion. Description of an easy clinical sign to detect extrusion of the medial meniscus at the anteromedial joint line. A varus stress test was applied in full extension before and after transosseous repair of an isolated traumatic avulsion of the posterior root of the medial meniscus in a 21-year-old patient. The clinical sign was verified by sectioning of the meniscotibial ligament during knee arthroplasty surgery in 3 patients. With a deficient posterior root, the clinical sign was positive, showing anteromedial extrusion under varus stress. After repair and at clinical follow-up, extrusion was normalized. Making the clinical diagnosis of medial meniscus extrusion after knee injury by applying a simple varus stress test to the knee and palpating the anteromedial meniscal extrusion might help physicians to suspect a medial meniscus root tear in the early stages after the injury as well as to evaluate its reduction after repair. A varus stress test in full extension should be performed systematically in patients where a root tear of the medial meniscus is suspected as well as after surgery to evaluate the success of the repair.

  10. Inference of emission rates from multiple sources using Bayesian probability theory.

    PubMed

    Yee, Eugene; Flesch, Thomas K

    2010-03-01

    The determination of atmospheric emission rates from multiple sources using inversion (regularized least-squares or best-fit technique) is known to be very susceptible to measurement and model errors in the problem, rendering the solution unusable. In this paper, a new perspective is offered for this problem: namely, it is argued that the problem should be addressed as one of inference rather than inversion. Towards this objective, Bayesian probability theory is used to estimate the emission rates from multiple sources. The posterior probability distribution for the emission rates is derived, accounting fully for the measurement errors in the concentration data and the model errors in the dispersion model used to interpret the data. The Bayesian inferential methodology for emission rate recovery is validated against real dispersion data, obtained from a field experiment involving various source-sensor geometries (scenarios) consisting of four synthetic area sources and eight concentration sensors. The recovery of discrete emission rates from three different scenarios obtained using Bayesian inference and singular value decomposition inversion are compared and contrasted.

  11. [Operative treatment of sacroiliac joint fracture and dislocation in Tile C pelvic fracture with Colorado 2 system].

    PubMed

    Liu, Shuping; Zhou, Qing; Liu, Yuehong; Chen, Xi; Zhou, Yu; Zhang, Desheng; Fang, Zhi; Xu, Wei

    2011-12-01

    To explore the effectiveness of Colorado 2 system in the stability reconstruction of sacroiliac joint fracture and dislocation in Tile C pelvic fracture. Between February 2009 and January 2011, 8 cases of Tile C pelvic fracture were treated with Colorado 2 system. There were 3 males and 5 females with an average age of 34.4 years (range, 22-52 years). Fractures were caused by traffic accident in 3 cases, by falling from height in 3 cases, and by crash of heavy object in 2 cases. According to Tile classification, 5 cases were classified as C1-2, 2 cases as C1-3, and 1 case as C2. The time between injury and operation was 5-10 days (mean, 7 days). After skeletal traction reduction, Colorado 2 system was used to fix sacroiliac joint, and reconstruction plate or external fixation was selectively adopted. The postoperative X-ray films showed that the reduction of vertical and rotatory dislocation was satisfactory, posterior pelvic ring achieved effective stability. All the incisions healed by first intention, and no blood vessel or nerve injury occurred. Eight patients were followed up 6-24 months (mean, 12 months). No loosening or breakage of internal fixation was observed and no re-dislocation of sacroiliac joint occurred. The bone healing time was 6-12 months (mean, 9 months). According to Majeed's functional criterion, the results were excellent in 5 cases, good in 2 cases, and fair in 1 case at last follow-up. Colorado 2 system could provide immediate stability of pelvic posterior ring and good maintenance of reduction effect, which is an effective method in the therapy of sacroiliac joint fracture and dislocation in Tile C pelvic fracture.

  12. Posterior distraction reduction and occipitocervical fixation for the treatment of basilar invagination and atlantoaxial dislocation.

    PubMed

    Meng, Yang; Chen, Hua; Lou, Jigang; Rong, Xin; Wang, Beiyu; Deng, Yuxiao; Ding, Chen; Hong, Ying; Liu, Hao

    2016-01-01

    To introduce a novel distraction technique for the treatment of basilar invagination (BI) and atlantoaxial dislocation (AAD) via a posterior-only approach. Twenty-one consecutive patients with BI and AAD who underwent posterior distraction reduction and occipitocervical fixation between January 2009 and June 2013 were enrolled in the present study. This novel distraction technique included two steps. First, the distraction between the occipitocervical junction of the rod (OCJR) and the occipital screws was performed to achieve horizontal and partial vertical reduction. Secondly, the distraction was performed between the C2 screws and OCJR to achieve complete vertical reduction. The pre- and postoperative JOA score, the extent of reduction, the fusion status, and the complications were recorded and analyzed. The mean follow-up was 18.3 months with a range of 10-32 months. No patient incurred neurovascular injury during surgery. The mean JOA score at the last follow-up (15.4) showed significant improvement (P<0.01) compared with the pre-operative parameters (11.2). Complete horizontal reduction was achieved in 18 patients (85.7%), and complete vertical reduction was achieved in 17 patients (80.9%). The rest patients are all received greater than 50% horizontal and vertical reduction. Solid fusion was achieved in 20 patients (95.2%). Mild dysphagia was observed in two patients. One patient suffered from postoperative fever and pulmonary infection. This novel distraction technique may provide satisfactory reduction via a posterior-only approach without exposure of the C1/2 facet joint. Therefore, it is a safe and effective method for the treatment of BI with AAD. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Posterior Cruciate Ligament Injury

    MedlinePlus

    ... tear. Contact sports. Athletes in sports such as football and soccer can tear their posterior cruciate ligament ... vehicle accident and participating in sports such as football and soccer are the most common risk factors ...

  14. Survivorship of standard versus modified posterior surgical approaches in metal-on-metal hip resurfacing.

    PubMed

    M Takamura, K; Maher, P; Nath, T; Su, E P

    2014-05-01

    Metal-on-metal hip resurfacing (MOMHR) is available as an alternative option for younger, more active patients. There are failure modes that are unique to MOMHR, which include loosening of the femoral head and fractures of the femoral neck. Previous studies have speculated that changes in the vascularity of the femoral head may contribute to these failure modes. This study compares the survivorship between the standard posterior approach (SPA) and modified posterior approach (MPA) in MOMHR. A retrospective clinical outcomes study was performed examining 351 hips (279 male, 72 female) replaced with Birmingham Hip Resurfacing (BHR, Smith and Nephew, Memphis, Tennessee) in 313 patients with a pre-operative diagnosis of osteoarthritis. The mean follow-up period for the SPA group was 2.8 years (0.1 to 6.1) and for the MPA, 2.2 years (0.03 to 5.2); this difference in follow-up period was statistically significant (p < 0.01). Survival analysis was completed using the Kaplan-Meier method. At four years, the Kaplan-Meier survival curve for the SPA was 97.2% and 99.4% for the MPA; this was statistically significant (log-rank; p = 0.036). There were eight failures in the SPA and two in the MPA. There was a 3.5% incidence of femoral head collapse or loosening in the SPA and 0.4% in the MPA, which represented a significant difference (p = 0.041). There was a 1.7% incidence of fractures of the femoral neck in the SPA and none in the MPA (p = 0.108). This study found a significant difference in survivorship at four years between the SPA and the MPA (p = 0.036). The clinical outcomes of this study suggest that preserving the vascularity of the femoral neck by using the MPA results in fewer vascular-related failures in MOMHRs. Cite this article: Bone Joint Res 2014;3:150-4. ©2014 The British Editorial Society of Bone & Joint Surgery.

  15. Does increased femoral antetorsion predispose to cartilage lesions of the patellofemoral joint?

    PubMed

    Oppermann, Johannes; Bredow, Jan; Wissusek, Boris; Spies, Christian Karl; Boese, Christoph Kolja; Chang, Shi-Min; Eysel, Peer; Dargel, Jens

    2017-09-01

    The purpose of this study was to investigate whether there was a relationship between femoral neck antetorsion and the presence and pattern of osteoarthritis of the patellofemoral joint. It was hypothesized that an increased femoral neck antetorsion (1) correlates with osteoarthritic changes of the lateral facet of the patellofemoral joint and (2) correlates with an increased lateral trochlear height and a decreased sulcus angle. Seventy-eight formalin-embedded cadaveric lower extremities from thirty-nine subjects with a median age of 74 years (range 60-88) were used. Surrounding soft tissues of the lower limb were removed. The femoral neck antetorsion was measured and referenced to the transepicondylar axis and the posterior condylar line. The height of the medial and lateral facet of the trochlea and the sulcus angle was measured. The location and the degree of patellofemoral cartilage degeneration were recorded. A Pearson's correlation analysis was performed to correlate the femoral neck antetorsion with the measured knee parameters. No significant correlation could be found between the femoral antetorsion and cartilage degeneration of the lateral patellofemoral joint (n.s.), the height of the lateral trochlea (n.s.) and the sulcus angle (n.s.). This study could not document that the femoral neck antetorsion and subsequent internal rotation of the distal femur correlated with the degree of degeneration of the lateral facet of the patellofemoral joint. Clinically, femoral internal rotation may play a minor role in the development of lateral patellofemoral joint degeneration.

  16. Tuberothalamic Artery Infarction Following Coil Embolization of a Ruptured Posterior Communicating Artery Aneurysm Belonging to a Transitional Type Posterior Cerebral Artery

    PubMed Central

    Lee, Kyeong Duk; Kwon, Soon Chan; Muniandy, Sarawana; Park, Eun Suk; Sim, Hong Bo; Lyo, In Uk

    2013-01-01

    Summary There are many potential anatomical variations in the connection between the internal carotid artery and the posterior circulation through the posterior communicating artery (PCoA). We describe the endovascular treatment of an aneurysm arising near the origin of the PCoA belonging to a transitional type posterior cerebral artery. Coil embolization subsequently resulted in thrombo-occlusion of the adjacent PCoA causing thalamic infarction even though sufficient retrograde flow had been confirmed pre-operatively by Allcock’s test. PMID:24070079

  17. On the quantification and efficient propagation of imprecise probabilities resulting from small datasets

    NASA Astrophysics Data System (ADS)

    Zhang, Jiaxin; Shields, Michael D.

    2018-01-01

    This paper addresses the problem of uncertainty quantification and propagation when data for characterizing probability distributions are scarce. We propose a methodology wherein the full uncertainty associated with probability model form and parameter estimation are retained and efficiently propagated. This is achieved by applying the information-theoretic multimodel inference method to identify plausible candidate probability densities and associated probabilities that each method is the best model in the Kullback-Leibler sense. The joint parameter densities for each plausible model are then estimated using Bayes' rule. We then propagate this full set of probability models by estimating an optimal importance sampling density that is representative of all plausible models, propagating this density, and reweighting the samples according to each of the candidate probability models. This is in contrast with conventional methods that try to identify a single probability model that encapsulates the full uncertainty caused by lack of data and consequently underestimate uncertainty. The result is a complete probabilistic description of both aleatory and epistemic uncertainty achieved with several orders of magnitude reduction in computational cost. It is shown how the model can be updated to adaptively accommodate added data and added candidate probability models. The method is applied for uncertainty analysis of plate buckling strength where it is demonstrated how dataset size affects the confidence (or lack thereof) we can place in statistical estimates of response when data are lacking.

  18. [Comparison of the Arthroscopic Finding in the Knee Joint and the MRI - Retrospective Study].

    PubMed

    Šimeček, K; Látal, P; Duda, J; Šimeček, M

    2017-01-01

    PURPOSE OF THE STUDY Our retrospective study presents the comparison of the preoperative magnetic resonance imaging of the knee joint - MRI - and the arthroscopic finding - ASC. Its aim is to find out how a positive or a negative finding of MRI corresponds with the operative finding and how much the experience of radiologist contributes to the conformity. MATERIAL AND METHODS The MRI findings of knee joints treated surgically at two departments in 2013 and 2014 were assessed. The MRI was performed in a total of 470 patients who subsequently underwent an arthroscopic surgery. A conformity or a non-conformity in anterior, posterior horn and complete rupture of both menisci and in partial or complete tear of anterior cruciate ligament - LCA was searched for. The sensitivity, specificity and accuracy of MRI were established. The difference between experienced and less experienced radiologists was evaluated. The analysis of the radiology report, surgical protocol of ASC and medical history in the documentation was performed. The cartilage was not subject to evaluation. The finding of Grade 1 meniscus tear on MRI was evaluated as negative. Grade 2 and Grade 3 were evaluated as positive. RESULTS Comparison of the preoperative MRI and the arthroscopic finding 1. The group with MRI reported 3 % of diagnostic arthroscopies. The control group without MRI (551 ASC) reported 15 % diagnostic arthroscopies. 2. Low sensitivity of MRI (0.67) in negative findings of ASC. It concerned 7 cases in which a pathological finding was identified on a MRI scan, but not by ASC. In two cases the repeated arthroscopy confirmed that a pathology inside the knee joint was overlooked by the arthroscopist. In the remaining five cases, the clinical finding improved without a repeated surgery. 3. High sensitivity of MRI is shown in the most frequent finding - posterior horn of medial meniscus (0.94). 4. Lower sensitivity (0.76) in partial and (0.83) in complete ACL tear. It increases to 0.93 if

  19. Dengue-Associated Posterior Reversible Encephalopathy Syndrome, Vietnam

    PubMed Central

    Mai, Nguyen Thi Hoang; Phu, Nguyen Hoan; Nghia, Ho Dang Trung; Phuong, Tran My; Duc, Du Trong; Chau, Nguyen Van Vinh; Wills, Bridget; Lim, Choie Cheio Tchoyoson; Thwaites, Guy; Simmons, Cameron Paul

    2018-01-01

    Dengue can cause neurologic complications in addition to the more common manifestations of plasma leakage and coagulopathy. Posterior reversible encephalopathy syndrome has rarely been described in dengue, although the pathophysiology of endothelial dysfunction likely underlies both. We describe a case of dengue-associated posterior reversible encephalopathy syndrome and discuss diagnosis and management. PMID:29350156

  20. Migration of titanium cable into spinal cord and spontaneous C2 and C3 fusion: Case report of possible causes of fatigue failure after posterior atlantoaxial fixation.

    PubMed

    Li, Huibo; Lou, Jigang; Liu, Hao

    2016-12-01

    Atlantoaxial instability is a common and serious injury of the upper cervical spine. Brooks' procedure is widely used to reconstruct the unstable atlantoaxial joint. The migration into spinal cord of titanium cable and spontaneous fusion between C2 and C3 has been little reported and the management of such a patient is difficult. We describe an unusual case of fatigue failure of posterior titanium atlantoaxial cable fixation with migration into the spinal cord and spontaneous fusion between C2 and C3. A 16-year-old girl complained of cervico-occipital pain with numbness and weakness of extremities 3 months ago. The girl underwent posterior C1-C2 arthrodesis with titanium cables and autogenous iliac crest bone grafting when she was 6 years old. When presented to our emergency department, imaging revealed the cracked titanium atlantoaxial cable and the spontaneous fusion between C2 and C3. Computed tomography demonstrated a broken wire with anterior migration of the cable into the spinal cord. The patient underwent posterior approach cervical spinal surgery to remove the broken cables. She remains neurologically intact a year following the posterior approach cervical spine surgery. Brooks' posterior stabilization could not effectively control rotation at the atlantoaxial articulation, so surgeons must be aware of the potential of fatigue failure of cables as well as the possibility of its migration into the spinal cord when using Brooks' posterior stabilization. Bilateral C1 lateral mass and C2 pedicle screw fixation or transarticular screw fixation are recommended by the authors in the event of rotatory instability.

  1. Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions.

    PubMed

    Tsuruike, Masaaki; Ellenbecker, Todd

    2014-11-14

    Context :  Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective :  To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design :  Cross-sectional study. Setting :  Health Science Laboratory. Patients or Other Participants :  A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s) :  Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results :  Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions :  Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

  2. Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

    PubMed Central

    Tsuruike, Masaaki; Ellenbecker, Todd S.

    2015-01-01

    Context: Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective: To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design: Cross-sectional study. Setting: Health Science Laboratory. Patients or Other Participants: A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s): Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results: Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions: Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited. PMID:25689561

  3. A joint latent class model for classifying severely hemorrhaging trauma patients.

    PubMed

    Rahbar, Mohammad H; Ning, Jing; Choi, Sangbum; Piao, Jin; Hong, Chuan; Huang, Hanwen; Del Junco, Deborah J; Fox, Erin E; Rahbar, Elaheh; Holcomb, John B

    2015-10-24

    In trauma research, "massive transfusion" (MT), historically defined as receiving ≥10 units of red blood cells (RBCs) within 24 h of admission, has been routinely used as a "gold standard" for quantifying bleeding severity. Due to early in-hospital mortality, however, MT is subject to survivor bias and thus a poorly defined criterion to classify bleeding trauma patients. Using the data from a retrospective trauma transfusion study, we applied a latent-class (LC) mixture model to identify severely hemorrhaging (SH) patients. Based on the joint distribution of cumulative units of RBCs and binary survival outcome at 24 h of admission, we applied an expectation-maximization (EM) algorithm to obtain model parameters. Estimated posterior probabilities were used for patients' classification and compared with the MT rule. To evaluate predictive performance of the LC-based classification, we examined the role of six clinical variables as predictors using two separate logistic regression models. Out of 471 trauma patients, 211 (45 %) were MT, while our latent SH classifier identified only 127 (27 %) of patients as SH. The agreement between the two classification methods was 73 %. A non-ignorable portion of patients (17 out of 68, 25 %) who died within 24 h were not classified as MT but the SH group included 62 patients (91 %) who died during the same period. Our comparison of the predictive models based on MT and SH revealed significant differences between the coefficients of potential predictors of patients who may be in need of activation of the massive transfusion protocol. The traditional MT classification does not adequately reflect transfusion practices and outcomes during the trauma reception and initial resuscitation phase. Although we have demonstrated that joint latent class modeling could be used to correct for potential bias caused by misclassification of severely bleeding patients, improvement in this approach could be made in the presence of time to event

  4. Patient and implant survival following joint replacement because of metastatic bone disease

    PubMed Central

    2013-01-01

    Background Patients suffering from a pathological fracture or painful bony lesion because of metastatic bone disease often benefit from a total joint replacement. However, these are large operations in patients who are often weak. We examined the patient survival and complication rates after total joint replacement as the treatment for bone metastasis or hematological diseases of the extremities. Patients and methods 130 patients (mean age 64 (30–85) years, 76 females) received 140 joint replacements due to skeletal metastases (n = 114) or hematological disease (n = 16) during the period 2003–2008. 21 replaced joints were located in the upper extremities and 119 in the lower extremities. Clinical and survival data were extracted from patient files and various registers. Results The probability of patient survival was 51% (95% CI: 42–59) after 6 months, 39% (CI: 31–48) after 12 months, and 29% (CI: 21–37) after 24 months. The following surgical complications were seen (8 of which led to additional surgery): 2–5 hip dislocations (n = 8), deep infection (n = 3), peroneal palsy (n = 2), a shoulder prosthesis penetrating the skin (n = 1), and disassembly of an elbow prosthesis (n = 1). The probability of avoiding all kinds of surgery related to the implanted prosthesis was 94% (CI: 89–99) after 1 year and 92% (CI: 85–98) after 2 years. Conclusion Joint replacement operations because of metastatic bone disease do not appear to have given a poorer rate of patient survival than other types of surgical treatment, and the reoperation rate was low. PMID:23530874

  5. Unsuccessful outcomes after posterior urethroplasty.

    PubMed

    Engel, Oliver; Fisch, Margit

    2015-03-01

    Posterior urethroplasty is the most common strategy for the treatment of post-traumatic urethral injuries. Especially in younger patients, post-traumatic injuries are a common reason for urethral strictures caused by road traffic accidents, with pelvic fracture or direct trauma to the perineum. In many cases early endoscopic realignment is the first attempt to restore the junction between proximal and distal urethra, but in some cases primary realignment is not possible or not enough to treat the urethral injury. In these cases suprapubic cystostomy alone and delayed repair by stricture excision and posterior urethroplasty is an alternative procedure to minimise the risk of stricture recurrence.

  6. The effect of deacetylated gellan gum on aesculin distribution in the posterior segment of the eye after topical administration.

    PubMed

    Chen, Qiuhong; Zheng, Yu; Li, Ye; Zeng, Ying; Kuang, Jianchao; Hou, Shixiang; Li, Xiaohui

    2012-05-01

    The aim of the present work was to evaluate the effect of deacetylated gellan gum on delivering hydrophilic drug to the posterior segment of the eye. An aesculin-containing in situ gel based on deacetylated gellan gum (AG) was prepared and characterized. In vitro corneal permeation across isolated rabbit cornea of aesculin between AG and aesculin solution (AS) was compared. The results showed that deacetylated gellan gum promotes corneal penetration of aesculin. Pharmacokinetics and ocular tissue distribution of aesculin after topical administration in rabbit eye showed that AG greatly improved aesculin accumulation in posterior segmentsrelative to AS, which was probably attributed to conjunctivital/sclera pathway. The area-under-the-curve (AUC) for AG in aqueous humor, choroid-retina, sclera and iris-ciliary body were significantly larger than those of AS. AG can be used as a potential carrier for broading the application of aesculin.

  7. Effect of stress concentration on the fatigue strength of A7N01S-T5 welded joints

    NASA Astrophysics Data System (ADS)

    Zhang, Mingyue; Gou, Guoqing; Hang, Zongqiu; Chen, Hui

    2017-07-01

    Stress concentration is a key factor that affects the fatigue strength of welded joints. In this study, the fatigue strengths of butt joints with and without the weld reinforcement were tested to quantify the effect of stress concentration. The fatigue strength of the welded joints was measured with a high-frequency fatigue machine. The P-S-N curves were drawn under different confidence levels and failure probabilities. The results show that butt joints with the weld reinforcement have much lower fatigue strength than joints without the weld reinforcement. Therefore, stress concentration introduced by the weld reinforcement should be controlled.

  8. Ankle Joint Angle and Lower Leg Musculotendinous Unit Responses to Cryotherapy.

    PubMed

    Akehi, Kazuma; Long, Blaine C; Warren, Aric J; Goad, Carla L

    2016-09-01

    Akehi, K, Long, BC, Warren, AJ, and Goad, CL. Ankle joint angle and lower leg musculotendinous unit responses to cryotherapy. J Strength Cond Res 30(9): 2482-2492, 2016-The use of cold application has been debated for its influence on joint range of motion (ROM) and stiffness. The purpose of this study was to determine whether a 30-minute ice bag application to the plantarflexor muscles or ankle influences passive ankle dorsiflexion ROM and lower leg musculotendinous stiffness (MTS). Thirty-five recreationally active college-aged individuals with no history of lower leg injury 6 months before data collection volunteered. On each testing day, we measured maximum passive ankle dorsiflexion ROM (°) and plantarflexor torque (N·m) on an isokinetic dynamometer to calculate the passive plantarflexor MTS (N·m per degree) at 4 joint angles before, during, and after a treatment. Surface electromyography amplitudes (μV), and skin surface and ambient air temperature (°C) were also measured. Subjects received an ice bag to the posterior lower leg, ankle joint, or nothing for 30 minutes in different days. Ice bag application to the lower leg and ankle did not influence passive ROM (F(12,396) = 0.67, p = 0.78). Passive torque increased after ice bag application to the lower leg (F(12,396) = 2.21, p = 0.011). Passive MTS at the initial joint angle increased after ice bag application to the lower leg (F(12,396) = 2.14, p = 0.014) but not at the other joint angles (p > 0.05). Surface electromyography amplitudes for gastrocnemius and soleus muscles increased after ice application to the lower leg (F(2,66) = 5.61, p = 0.006; F(12,396) = 3.60, p < 0.001). Ice bag application to the lower leg and ankle joint does not alter passive dorsiflexion ROM but increases passive ankle plantarflexor torque in addition to passive ankle plantarflexor MTS at the initial joint angle.

  9. A late neurological complication following posterior correction surgery of severe cervical kyphosis.

    PubMed

    Hojo, Yoshihiro; Ito, Manabu; Abumi, Kuniyoshi; Kotani, Yoshihisa; Sudo, Hideki; Takahata, Masahiko; Minami, Akio

    2011-06-01

    Though a possible cause of late neurological deficits after posterior cervical reconstruction surgery was reported to be an iatrogenic foraminal stenosis caused not by implant malposition but probably by posterior shift of the lateral mass induced by tightening screws and plates, its clinical features and pathomechanisms remain unclear. The aim of this retrospective clinical review was to investigate the clinical features of these neurological complications and to analyze the pathomechanisms by reviewing pre- and post-operative imaging studies. Among 227 patients who underwent cervical stabilization using cervical pedicle screws (CPSs), six patients who underwent correction of cervical kyphosis showed postoperative late neurological complications without any malposition of CPS (ND group). The clinical courses of the patients with deficits were reviewed from the medical records. Radiographic assessment of the sagittal alignment was conducted using lateral radiographs. The diameter of the neural foramen was measured on preoperative CT images. These results were compared with the other 14 patients who underwent correction of cervical kyphosis without late postoperative neurological complications (non-ND group). The six patients in the ND group showed no deficits in the immediate postoperative periods, but unilateral muscle weakness of the deltoid and biceps brachii occurred at 2.8 days postoperatively on average. Preoperative sagittal alignment of fusion area showed significant kyphosis in the ND group. The average of kyphosis correction in the ND was 17.6° per fused segment (range 9.7°-35.0°), and 4.5° (range 1.3°-10.0°) in the non-ND group. A statistically significant difference was observed in the degree of preoperative kyphosis and the correction angles at C4-5 between the two groups. The diameter of the C4-5 foramen on the side of deficits was significantly smaller than that of the opposite side in the ND group. Late postoperative neurological

  10. Effects of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: Finite element modeling of cadaver specimens.

    PubMed

    Lewis, Gregory S; Conaway, William K; Wee, Hwabok; Kim, H Mike

    2017-02-28

    A novel technique of "anterior offsetting" of the humeral head component to address posterior instability in total shoulder arthroplasty has been proposed, and its biomechanical benefits have been previously demonstrated experimentally. The present study sought to characterize the changes in joint mechanics associated with anterior offsetting with various amounts of glenoid retroversion using cadaver specimen-specific 3-dimensional finite element models. Specimen-specific computational finite element models were developed through importing digitized locations of six musculotendinous units of the rotator cuff and deltoid muscles based off three cadaveric shoulder specimens implanted with total shoulder arthroplasty in either anatomic or anterior humeral head offset. Additional glenoid retroversion angles (0°, 10°, 20°, and 30°) other than each specimen׳s actual retroversion were modeled. Contact area, contact force, peak pressure, center of pressure, and humeral head displacement were calculated at each offset and retroversion for statistical analysis. Anterior offsetting was associated with significant anterior shift of center of pressure and humeral head displacement upon muscle loading (p<0.05). Although statistically insignificant, anterior offsetting was associated with increased contact area and decreased peak pressure (p > 0.05). All study variables showed significant differences when compared between the 4 different glenoid retroversion angles (p < 0.05) except for total force (p < 0.05). The study finding suggests that the anterior offsetting technique may contribute to joint stability in posteriorly unstable shoulder arthroplasty and may reduce eccentric loading on glenoid components although the long term clinical results are yet to be investigated in future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Femoral Component External Rotation Affects Knee Biomechanics: A Computational Model of Posterior-stabilized TKA.

    PubMed

    Kia, Mohammad; Wright, Timothy M; Cross, Michael B; Mayman, David J; Pearle, Andrew D; Sculco, Peter K; Westrich, Geoffrey H; Imhauser, Carl W

    2018-01-01

    The correct amount of external rotation of the femoral component during TKA is controversial because the resulting changes in biomechanical knee function associated with varying degrees of femoral component rotation are not well understood. We addressed this question using a computational model, which allowed us to isolate the biomechanical impact of geometric factors including bony shapes, location of ligament insertions, and implant size across three different knees after posterior-stabilized (PS) TKA. Using a computational model of the tibiofemoral joint, we asked: (1) Does external rotation unload the medial collateral ligament (MCL) and what is the effect on lateral collateral ligament tension? (2) How does external rotation alter tibiofemoral contact loads and kinematics? (3) Does 3° external rotation relative to the posterior condylar axis align the component to the surgical transepicondylar axis (sTEA) and what anatomic factors of the femoral condyle explain variations in maximum MCL tension among knees? We incorporated a PS TKA into a previously developed computational knee model applied to three neutrally aligned, nonarthritic, male cadaveric knees. The computational knee model was previously shown to corroborate coupled motions and ligament loading patterns of the native knee through a range of flexion. Implant geometries were virtually installed using hip-to-ankle CT scans through measured resection and anterior referencing surgical techniques. Collateral ligament properties were standardized across each knee model by defining stiffness and slack lengths based on the healthy population. The femoral component was externally rotated from 0° to 9° relative to the posterior condylar axis in 3° increments. At each increment, the knee was flexed under 500 N compression from 0° to 90° simulating an intraoperative examination. The computational model predicted collateral ligament forces, compartmental contact forces, and tibiofemoral internal/external and

  12. Topographically Organized Projection to Posterior Insular Cortex from the Posterior Portion of the Ventral Medial Nucleus (VMpo) in the Long-tailed Macaque Monkey

    PubMed Central

    Craig, A.D. (Bud)

    2014-01-01

    Prior anterograde tracing work identified somatotopically organized lamina I trigemino- and spino-thalamic terminations in a cytoarchitectonically distinct portion of posterolateral thalamus of the macaque monkey, named the posterior part of the ventral medial nucleus (VMpo; Craig, 2004b). Microelectrode recordings from clusters of selectively thermoreceptive or nociceptive neurons were used to guide precise micro-injections of various tracers in VMpo. A prior report (Craig and Zhang, 2006) described retrograde tracing results, which confirmed the selective lamina I input to VMpo and the antero-posterior (head to foot) topography. The present report describes the results of micro-injections of anterograde tracers placed at different levels in VMpo, based on the antero-posterior topographic organization of selectively nociceptive units and clusters over nearly the entire extent of VMpo. Each injection produced dense, patchy terminal labeling in a single coherent field within a distinct granular cortical area centered in the fundus of the superior limiting sulcus. The terminations were distributed with a consistent antero-posterior topography over the posterior half of the superior limiting sulcus. These observations demonstrate a specific VMpo projection area in dorsal posterior insular cortex that provides the basis for a somatotopic representation of selectively nociceptive lamina I spinothalamic activity. These results also identify the VMpo terminal area as the posterior half of interoceptive cortex; the anterior half receives input from the vagal-responsive and gustatory neurons in the basal part of the ventral medial nucleus (VMb). PMID:23853108

  13. The probability of object-scene co-occurrence influences object identification processes.

    PubMed

    Sauvé, Geneviève; Harmand, Mariane; Vanni, Léa; Brodeur, Mathieu B

    2017-07-01

    Contextual information allows the human brain to make predictions about the identity of objects that might be seen and irregularities between an object and its background slow down perception and identification processes. Bar and colleagues modeled the mechanisms underlying this beneficial effect suggesting that the brain stocks information about the statistical regularities of object and scene co-occurrence. Their model suggests that these recurring regularities could be conceptualized along a continuum in which the probability of seeing an object within a given scene can be high (probable condition), moderate (improbable condition) or null (impossible condition). In the present experiment, we propose to disentangle the electrophysiological correlates of these context effects by directly comparing object-scene pairs found along this continuum. We recorded the event-related potentials of 30 healthy participants (18-34 years old) and analyzed their brain activity in three time windows associated with context effects. We observed anterior negativities between 250 and 500 ms after object onset for the improbable and impossible conditions (improbable more negative than impossible) compared to the probable condition as well as a parieto-occipital positivity (improbable more positive than impossible). The brain may use different processing pathways to identify objects depending on whether the probability of co-occurrence with the scene is moderate (rely more on top-down effects) or null (rely more on bottom-up influences). The posterior positivity could index error monitoring aimed to ensure that no false information is integrated into mental representations of the world.

  14. T2 Mapping of the Sacroiliac Joints With 3-T MRI: A Preliminary Study.

    PubMed

    Lefebvre, Guillaume; Bergère, Antonin; Rafei, Mazen El; Duhamel, Alain; Teixeira, Pedro; Cotten, Anne

    2017-08-01

    The objective of this study was to assess the feasibility of T2 relaxation time measurements of the sacroiliac joints. The sacroiliac joints of 40 patients were imaged by 3-T MRI using an oblique axial multislice multiecho spin-echo T2-weighted sequence. Manual plotting and automatic subdivision of ROIs allowed us to obtain T2 values for up to 48 different areas per patient (posterior and anterior parts, sacral, intermediate, and iliac parts). Intraand interobserver reproducibility of T2 values were calculated after independent assessment by two musculoskeletal radiologists. A total of 1656 measurement sites could be analyzed. Mean (± SD) T2 values were 40.6 ± 6.7 ms and 41.2 ± 6.3 ms for observer 1 and 39.9 ± 6.6 ms for observer 2. The intraobserver intraclass correlation coefficient was 0.72 (95% CI, 0.70-0.74), and the interobserver intraclass correlation coefficient was 0.71 (95% CI, 0.68-0.72). Our study shows the feasibility of T2 relaxation time measurements at the sacroiliac joints.

  15. Background for Joint Systems Aspects of AIR 6000

    DTIC Science & Technology

    2000-04-01

    Checkland’s Soft Systems Methodology [7, 8,9]. The analytical techniques that are proposed for joint systems work are based on calculating probability...Supporting Global Interests 21 DSTO-CR-0155 SLMP Structural Life Management Plan SOW Stand-Off Weapon SSM Soft Systems Methodology UAV Uninhabited Aerial... Systems Methodology in Action, John Wiley & Sons, Chichester, 1990. [101 Pearl, Judea, Probabilistic Reasoning in Intelligent Systems: Networks of Plausible

  16. Infundibular dilatation of the posterior communicating artery in a defined population.

    PubMed

    Vlajković, Slobodan; Vasović, Ljiljana; Trandafilović, Milena; Jovanović, Ivan; Ugrenović, Slađana; Dorđević, Gordana

    2015-01-01

    Unusual widening of the posterior communicating artery (PCoA) at its beginning from the cerebral portion of the internal carotid artery (ICA) was described as its infundibular dilatation (ID). A possibility of ID rupture or progression to aneurysm was the reason for an investigation of its frequency and morphologic features in specimens of the Serbian population. Cerebral arteries on the brain base of 267 adult cadavers of both genders and varying age and causes of death were dissected. The images of the PCoA in 190 fetuses were also reviewed. ID of the PCoA was defined as a funnel shaped beginning of different width from ICA, wherein PCoA continues from ID apex to the posterior cerebral artery. There were no cases of ID in fetuses. ID and aneurysms of the PCoA were found in 6/267 or 2.2% and 3/267 or 1.12% of adults, respectively. Unilaterally, they existed on the left side and, frequently, in male cases aging 70 years and older, that had died without cerebral cause. Bilaterally, ID was found in 2/6 cases. There was only one case of ID and aneurysm of the PCoA, but from the ID. We are of the opinion that ID of the PCoA only develops postnatally and probably is due to the influence of hemodynamic factors or hypertension. Copyright © 2014 Elsevier GmbH. All rights reserved.

  17. The treatment options for posterior malleolar fractures in tibial spiral fractures.

    PubMed

    Guo, Jialiang; Liu, Lei; Yang, Zongyou; Hou, Zhiyong; Chen, Wei; Zhang, Yingze

    2017-09-01

    The posterior malleolar fracture (PMF) in tibial spiral fractures are a common type of complication that occurs in tibial fractures. However, the indication of fixation for posterior fractures is still under debate and varies between different surgeons'. It is not unusual to find the smaller PMF (<25%), which could be treated conservatively within guidelines, treated with internal fixation in clinic. The aim of this study is to evaluate the clinical outcomes of tibial spiral fractures with PMF and provide proper guidance for the treatment of this special fracture. A total of 284 cases of spiral fractures combined with PMF were collected and analyzed. Demographic data, fragment size (classified by 25% involvement of ankle joint), time to weight-bearing and functional scores post-operatively were recorded. The ankle-hindfoot scale of the American Orthopaedic Foot and Ankle Society (AOFAS), a visual analogue scale (VAS) pain score, assessment of dorsiflexion restriction and arthritis scale were used as the main evaluations. Forty patients with a larger PMF (≥25%) and 72 with smaller ones (<25%) were fixed and categorized as the fixation group (FG). In the nonfixation group (NG), the corresponding numbers were four and 168 patients respectively. A total of 279 PMF were classified as large posterolateral triangular fragment carrying the posterior half of the fibular notch and intra-incisural posterolateral fragment involving one-fourth to one-third of the fibular notch. However, no obvious differences were observed in terms of the clinical outcomes in PMF involving one-fourth to one-third of the fibular notch. In the treatment of smaller PMF (<25%) of this type, there were no obvious differences in the functional outcomes between fixed (SF) and nonfixed PMF (SN). Many patients with smaller PMFs were fixated, but functional outcomes of SF were not better than those of SN. There is no need to emphasize other factors guiding the treatment of PMF involving one-fourth to

  18. Effect of cage design, supplemental posterior instrumentation and approach on primary stability of a lumbar interbody fusion - A biomechanical in vitro study.

    PubMed

    Schmoelz, Werner; Sandriesser, Sabrina; Loebl, Oded; Bauer, Marlies; Krappinger, Dietmar

    2017-10-01

    There are various techniques and approaches for lumbar interbody fusion differing in access, cage type and type of supplemental posterior instrumentation. While a transforaminal access usually includes a hemifacetectomy, the facet joint can be preserved with a more lateral extraforaminal access. The supplemental posterior instrumentation required for both fusion techniques is still debated. The purpose of the present study was to compare primary stability of the two accesses for two different cage types with none, unilateral and bilateral supplemental posterior instrumentation. Six monosegmental lumbar functional spinal units (FSUs) were included in each of the two groups, and subjected to a flexibility test. As cages, a newly designed cage was compared to a standard cage in the following states: (a) native, (b) stand-alone cage, (c) bilateral internal fixator, (d) unilateral internal fixator, (e) unilateral facetectomy+bilateral internal fixator, (f) unilateral facetectomy+unilateral internal fixator and (g) unilateral facetectomy with stand-alone cage. For comparison the range of motion was normalized to the native state and the effects of the facetectomy, cage type, and supplemental instrumentation was compared. Within the subject comparison showed a significantly higher flexibility for the unilateral facetectomy in all motion directions (p<0.001). In between subject comparison showed a significant effect of cage type on flexibility in flexion/extension (p=0.002) and lateral bending (p=0.028) but not in axial rotation (p=0.322). The type of supplemental posterior fixation had a significant effect on the flexibility in all motion directions (stand-alone>unilateral fixator>bilateral fixator). Cage design and approach type are affecting the primary stability of lumbar interbody fusion procedures while the type of posterior instrumentation is the most influencing factor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Three-Dimensional Lower Extremity Joint Loading in a Carved Ski and Snowboard Turn: A Pilot Study

    PubMed Central

    Müller, Erich

    2014-01-01

    A large number of injuries to the lower extremity occur in skiing and snowboarding. Due to the difficulty of collecting 3D kinematic and kinetic data with high accuracy, a possible relationship between injury statistic and joint loading has not been studied. Therefore, the purpose of the current study was to compare ankle and knee joint loading at the steering leg between carved ski and snowboard turns. Kinetic data were collected using mobile force plates mounted under the toe and heel part of the binding on skies or snowboard (KISTLER). Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. An extended version of the Yeadon model was applied to calculate inertial properties of the segments. Ankle and knee joint forces and moments were calculated using inverse dynamic analysis. Results showed higher forces along the longitudinal axis in skiing and similar forces for skiing and snowboarding in anterior-posterior and mediolateral direction. Joint moments were consistently greater during a snowboard turn, but more fluctuations were observed in skiing. Hence, when comparing joint loading between carved ski and snowboard turns, one should differentiate between forces and moments, including the direction of forces and moments and the turn phase. PMID:25317202

  20. The Efficacy of Consensus Tree Methods for Summarizing Phylogenetic Relationships from a Posterior Sample of Trees Estimated from Morphological Data.

    PubMed

    O'Reilly, Joseph E; Donoghue, Philip C J

    2018-03-01

    Consensus trees are required to summarize trees obtained through MCMC sampling of a posterior distribution, providing an overview of the distribution of estimated parameters such as topology, branch lengths, and divergence times. Numerous consensus tree construction methods are available, each presenting a different interpretation of the tree sample. The rise of morphological clock and sampled-ancestor methods of divergence time estimation, in which times and topology are coestimated, has increased the popularity of the maximum clade credibility (MCC) consensus tree method. The MCC method assumes that the sampled, fully resolved topology with the highest clade credibility is an adequate summary of the most probable clades, with parameter estimates from compatible sampled trees used to obtain the marginal distributions of parameters such as clade ages and branch lengths. Using both simulated and empirical data, we demonstrate that MCC trees, and trees constructed using the similar maximum a posteriori (MAP) method, often include poorly supported and incorrect clades when summarizing diffuse posterior samples of trees. We demonstrate that the paucity of information in morphological data sets contributes to the inability of MCC and MAP trees to accurately summarise of the posterior distribution. Conversely, majority-rule consensus (MRC) trees represent a lower proportion of incorrect nodes when summarizing the same posterior samples of trees. Thus, we advocate the use of MRC trees, in place of MCC or MAP trees, in attempts to summarize the results of Bayesian phylogenetic analyses of morphological data.