Reduced Scleral TIMP-2 Expression Is Associated With Myopia Development: TIMP-2 Supplementation Stabilizes Scleral Biomarkers of Myopia and Limits Myopia Development.

PubMed

Liu, Hsin-Hua; Kenning, Megan S; Jobling, Andrew I; McBrien, Neville A; Gentle, Alex

2017-04-01

The purpose of this study was to determine the endogenous regulation pattern of tissue inhibitor of metalloproteinase-2 (TIMP-2) in the tree shrew sclera during myopia development and investigate the capacity of exogenous TIMP-2 to inhibit matrix metalloproteinase-2 (MMP-2) in vitro and both scleral collagen degradation and myopia development in vivo. TIMP-2 expression in the sclera during myopia development was assessed using polymerase chain reaction. In vitro TIMP-2 inhibition of MMP-2 was investigated using a gelatinase activity plate assay and zymography. Tree shrews were injected with a collagen precursor before undergoing monocular form deprivation and concurrent daily subconjunctival injections of either TIMP-2 or vehicle to the form-deprived eye. In vivo ocular biometry changes were monitored, and scleral tissue was collected after 12 days and assayed for collagen degradation. The development of myopia was associated with a mean reduction in TIMP-2 mRNA expression after 5 days of form deprivation (P < 0.01). Both activation and activity of MMP-2 were inhibited by TIMP-2 with an IC50 of 10 to 20 and 2 nM, respectively. In vivo exogenous addition of TIMP-2 significantly reduced myopia development (P < 0.01), due to reduced vitreous chamber elongation (P < 0.01). In vivo TIMP-2 treatment also significantly inhibited posterior scleral collagen degradation relative to vehicle-treated eyes (P < 0.01), with levels similar to those in control eyes. Myopia development in mammals is associated with reduced expression of TIMP-2, which contributes to increased degradative activity in the sclera. It follows that replenishment of this TIMP-2 significantly reduced the rate of both scleral collagen degradation and myopia development.

21 CFR 886.3800 - Scleral shell.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a...

21 CFR 886.3800 - Scleral shell.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a...

Iris-Claw Intraocular Lens and Scleral-Fixated Posterior Chamber Intraocular Lens Implantations in Correcting Aphakia: A Meta-Analysis.

PubMed

Jing, Wu; Guanlu, Liang; Qianyin, Zheng; Shuyi, Li; Fengying, He; Jian, Liu; Wen, Xu

2017-07-01

A meta-analysis to compare iris-claw intraocular lens (IC-IOL) and scleral-fixated posterior chamber intraocular lens (SF-PCIOL) implantations in correcting aphakia without sufficient capsular support. Eligible studies were collected through PubMed, Web of Science, Embase, and the Cochrane library. The pooled relative risks (RR), pooled standardized mean difference (SMD), and their 95% confidence interval of the eligible studies were then calculated. Seven studies met our inclusion criteria, involving 232 and 158 eyes in IC-IOL and SF-PCIOL groups, respectively. The pooled SMD of the mean postoperative corrected distance visual acuity (CDVA) (logMAR) was -0.25. The pooled RR of the eyes achieving 20/40 or better postoperatively was 1.16. The pooled SMD of the surgical time was -2.97. The pooled RR of the surgical complications was 0.86. The pooled RR of IOL dislocation, retinal detachment (RD), and cystoid macular edema (CME) between the two groups were 0.22, 0.63, and 0.64. Implantation of IC-IOL has a more simple procedure and shorter learning curve than SF-PCIOL implantation in correcting aphakia without sufficient capsular support.

Scleral lens use in dry eye syndrome.

PubMed

Bavinger, J Clay; DeLoss, Karen; Mian, Shahzad I

2015-07-01

Dry eye syndrome can be difficult to manage in severe or refractory cases. In patients in whom traditional treatments have limited efficacy, alternative treatments may be considered for dry eye syndrome, including scleral lenses. The present review summarizes the evidence regarding scleral lens use in dry eye syndrome. Scleral lenses have become a viable option for severe dry eye syndrome, and have been shown to be efficacious and well tolerated, with most reports citing improved visual acuity and relief of symptoms. Currently, there are 18 manufacturers of scleral lenses, although published reports on scleral lenses primarily focus on the BostonSight PROSE and the Jupiter Lens. Scleral lenses are efficacious and well tolerated for use in severe dry eye syndrome. Further research is needed to compare different sizes and types of lenses, and to standardize outcome measures.

Intramembranous ossification of scleral ossicles in Chelydra serpentina.

PubMed

Franz-Odendaal, Tamara A

2006-01-01

Scleral ossicles are present in many reptiles, including turtles and birds. In both groups the sclerotic ring situated in the eye is composed of a number of imbricating scleral ossicles or plates. Despite this gross morphological similarity, Andrews (1996. An endochondral rather than a dermal origin for scleral ossicles in Cryptodiran turtles. J. Herpetol. 30, 257-260) reported that the scleral ossicles of turtles develop endochondrally unlike those in birds, which develop intramembranously after a complex epithelial-mesenchymal inductive event. This study re-explores one of the species examined by Andrews in order to determine the mode of ossification of scleral ossicles in turtles. A growth series of Chelydra serpentina embryos, including the stages examined by Andrews, were examined by staining separately for cartilage and bone. Results clearly contradict Andrews (1996) and show that the scleral ossicles of Chelydra serpentina develop similarly to those in birds. That is, they develop intramembranously without a cartilage precursor and are likely induced by transient scleral papillae. The sequence of scleral papillae development is broadly similar, but the papillae themselves are not as distinct as those seen in chicken embryos. This study has important consequences for understanding the homology of scleral ossicles among tetrapods.

Studies of Scleral Biomechanical Behavior Related to Susceptibility for Retinal Ganglion Cell Loss in Experimental Mouse Glaucoma

PubMed Central

Nguyen, Cathy; Cone, Frances E.; Nguyen, Thao D.; Coudrillier, Baptiste; Pease, Mary E.; Steinhart, Matthew R.; Oglesby, Ericka N.; Jefferys, Joan L.; Quigley, Harry A.

2013-01-01

Purpose. To study anatomical changes and mechanical behavior of the sclera in mice with experimental glaucoma by comparing CD1 to B6 mice. Methods. Chronic experimental glaucoma for 6 weeks was produced in 2- to 4-month-old CD1 (43 eyes) and B6 mice (42 eyes) using polystyrene bead injection into the anterior chamber with 126 control CD1 and 128 control B6 eyes. Intraocular pressure (IOP) measurements were made with the TonoLab at baseline and after bead injection. Axial length and scleral thickness were measured after sacrifice in the CD1 and B6 animals and compared to length data from 78 eyes of DBA/2J mice. Inflation testing of posterior sclera was conducted, and circumferential and meridional strain components were determined from the displacement response. Results. Experimental glaucoma led to increases in axial length and width by comparison to fellow eyes (6% in CD1 and 10% in B6; all P < 0.03). While the peripapillary sclera became thinner in both mouse types with glaucoma, the remainder of the sclera uniformly thinned in CD1, but thickened in B6. Peripapillary sclera in CD1 controls had significantly greater temporal meridional strain than B6 and had differences in the ratios of meridional to effective circumferential strain from B6 mice. In both CD1 and B6 mice, exposure to chronic IOP elevation resulted in stiffer pressure–strain responses for both the effective circumferential and meridional strains (multivariable regression model, P = 0.01–0.03). Conclusions. Longer eyes, greater scleral strain in some directions at baseline, and generalized scleral thinning after glaucoma were characteristic of CD1 mice that have greater tendency to retinal ganglion cell damage than B6 mice. Increased scleral stiffness after glaucoma exposure in mice mimics findings in monkey and human glaucoma eyes. PMID:23404116

Change in intraocular pressure during scleral depression.

PubMed

Trevino, Richard; Stewart, Brandi

2015-01-01

Manometric studies have found that intraocular pressure (IOP) rises 116-350 mmHg during scleral depression in surgical settings. No information is available regarding the effect of scleral depression on IOP in routine clinical settings. The aim of this study is to quantify the change in IOP that occurs when scleral depression is performed on normal eyes in a routine clinical setting. A total of 28 eyes from 28 normal subjects were included. Tono-Pen tonometry was performed while scleral depression was performed in each of the two quadrants: superotemporal (ST) and inferonasal (IN). A post-procedure IOP measurement was obtained following each scleral depression examination. Both ST and IN quadrants were tested on all eyes, with the quadrant tested first chosen at random (15 ST, 13 IN). The mean IOP during scleral depression was 65.3 mmHg ST and 47.8 mmHg IN, with a maximum recorded IOP of 88 mmHg. The mean change in IOP for the ST quadrant was 51.9 ± 17.3 mmHg and 46.4 ± 16.0 mmHg for the right and left eyes, respectively. The mean change in IOP for the IN quadrant was 45.3 ± 22.7 mmHg and 16.8 ± 15.8 mmHg for the right and left eyes, respectively. Scleral depression as performed in a routine office setting produces wide fluctuations in IOP and may impair ocular perfusion. Additional studies are needed to determine the long-term consequences of routine scleral depression. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Acanthamoeba keratitis in patients wearing scleral contact lenses.

PubMed

Sticca, Matheus Porto; Carrijo-Carvalho, Linda C; Silva, Isa M B; Vieira, Luiz A; Souza, Luciene B; Junior, Rubens Belfort; Carvalho, Fábio Ramos S; Freitas, Denise

2018-06-01

To report a series of cases of Acanthamoeba keratitis (AK) in scleral lens wearers with keratoconus to determine whether this type of contact lens presents a greater risk for development of infection. This study reports three patients who wore scleral contact lenses to correct keratoconus and developed AK. The diagnoses of AK were established based on cultures of the cornea, scleral contact lenses, and contact lens paraphernalia. This study investigated the risk factors for infections. The possible risks for AK in scleral contact lens wearers are hypoxic changes in the corneal epithelium because of the large diameter and minimal tear exchange, use of large amounts of saline solution necessary for scleral lens fitting, storing the scleral lens overnight in saline solution rather than contact lens multipurpose solutions, not rubbing the contact lens during cleaning, and the space between the cornea and the back surface of the scleral lens that might serve as a fluid reservoir and environment for Acanthamoeba multiplication. Two patients responded well to medical treatment of AK; one is still being treated. The recommendations for use and care of scleral contact lenses should be emphasized, especially regarding use of sterile saline (preferably single use), attention to rubbing the lens during cleaning, cleaning of the plunger, and overnight storage in fresh contact lens multipurpose solutions without topping off the lens solution in the case. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

The use of donor scleral patch in ophthalmic surgery.

PubMed

Hodge, Christopher; Sutton, Gerard; Devasahayam, Raj; Georges, Pierre; Treloggen, Jane; Cooper, Simon; Petsoglou, Con

2017-03-01

Scleral tissue has been in use in ophthalmology for many years although indications for use have varied. We retrospectively reviewed scleral transplant tissue requests over a 12 month period at a local eye bank and confirmed a small but significant demand for the use of scleral tissue. Iatrogenic surgical complications are the primary indication for use. Our understanding of the indications and outcomes of scleral graft procedures is derived from case reports and small cohort series. We reviewed the current literature on existing indications for its use and discuss the relative outcomes. To our knowledge this represents the first review of scleral transplant indications and further summarises usage rates in the Lions NSW Eye Bank which may provide practical information for those surgeons who use scleral tissue and Eye Banks who supply it.

Scleral buckle infection by Serratia species.

PubMed

Venkatesh, Ramesh; Agarwal, Manisha; Singh, Shalini; Mayor, Rahul; Bansal, Aditya

2017-01-01

We describe a rare case of scleral buckle (SB) infection with Serratia species. A 48-year-old male with a history of retinal detachment repair with scleral buckling presented with redness, pain, and purulent discharge in the left eye for 4 days. Conjunctival erosion with exposure of the SB and scleral thinning was noted. The SB was removed and sent for culture. Blood and chocolate agar grew Gram-negative rod-shaped bacillus identified as Serratia marcescens . On the basis of the susceptibility test results, the patient was treated with oral and topical antibiotics. After 6 weeks of the treatment, his infection resolved.

Orbital cellulitis following silicone-sponge scleral buckles

PubMed Central

Nemet, Arie Y; Ferencz, Joseph R; Segal, Ori; Meshi, Amit

2013-01-01

Background Acute or chronic infection of the scleral explant is rare. We report seven cases of scleral explant infections that caused orbital cellulitis. Materials and methods This was a retrospective chart review of oculoplastics at oculoplastics and vitreo-retinal units in a secondary referral hospital. All subjects had orbital cellulitis secondary to scleral buckle in the range of January 1990 to March 2010. Demographics, imaging studies, and pathology specimens were reviewed. Results A total of 841 silicone-sponge scleral buckle implants for rhegmatogenous retinal detachment were performed. Forty were extracted (4.75%; annual rate of 1.9 cases). Seven (0.83%) had orbital cellulitis. The mean time from implantation to presentation was 5.7 years. There was bacterial growth in all specimens, with Staphylococcus aureus in four. Conclusions Patients who are operated on with silicone-sponge scleral buckling for rhegmatogenous retinal detachment sometimes require removal of the implant because of infection. However, the infection rate is low. Patients should be followed in the long term for possible complications. PMID:24204118

Scleral topography analysed by optical coherence tomography.

PubMed

Bandlitz, Stefan; Bäumer, Joachim; Conrad, Uwe; Wolffsohn, James

2017-08-01

A detailed evaluation of the corneo-scleral-profile (CSP) is of particular relevance in soft and scleral lenses fitting. The aim of this study was to use optical coherence tomography (OCT) to analyse the profile of the limbal sclera and to evaluate the relationship between central corneal radii, corneal eccentricity and scleral radii. Using OCT (Optos OCT/SLO; Dunfermline, Scotland, UK) the limbal scleral radii (SR) of 30 subjects (11M, 19F; mean age 23.8±2.0SD years) were measured in eight meridians 45° apart. Central corneal radii (CR) and corneal eccentricity (CE) were evaluated using the Oculus Keratograph 4 (Oculus, Wetzlar, Germany). Differences between SR in the meridians and the associations between SR and corneal topography were assessed. Median SR measured along 45° (58.0; interquartile range, 46.8-84.8mm) was significantly (p<0.001) flatter than along 0° (30.7; 24.5-44.3mm), 135° (28.4; 24.9-30.9mm), 180° (23.40; 21.3-25.4mm), 225° (25.8; 22.4-32.4mm), 270° (28.8; 25.3-33.1mm), 315° (30.0; 25.0-36.9mm), and 90° (37.1; 29.1-43.4mm). In addition, the nasal SR along 0° were significant flatter than the temporal SR along 180° (p<0.001). Central corneal radius in the flat meridian (7.83±0.26mm) and in the steep meridian (7.65±0.26mm) did not correlate with SR (p=0.186 to 0.998). There was no statistically significant correlation between corneal eccentricity and scleral radii in each meridian (p=0.422). With the OCT device used in this study it was possible to measure scleral radii in eight different meridians. Scleral radii are independent of corneal topography and may provide additional data useful in fitting soft and scleral contact lenses. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

21 CFR 886.4155 - Scleral plug.

Code of Federal Regulations, 2014 CFR

2014-04-01

... stainless steel with or without a gold, silver, or titanium coating. The special controls for the surgical grade stainless steel scleral plug (with or without a gold, silver, or titanium coating) are: (i) The... titanium coating). The special controls for scleral plugs made of other materials are: (i) The device must...

Precise measurement of scleral radius using anterior eye profilometry.

PubMed

Jesus, Danilo A; Kedzia, Renata; Iskander, D Robert

2017-02-01

To develop a new and precise methodology to measure the scleral radius based on anterior eye surface. Eye Surface Profiler (ESP, Eaglet-Eye, Netherlands) was used to acquire the anterior eye surface of 23 emmetropic subjects aged 28.1±6.6years (mean±standard deviation) ranging from 20 to 45. Scleral radius was obtained based on the approximation of the topographical scleral data to a sphere using least squares fitting and considering the axial length as a reference point. To better understand the role of scleral radius in ocular biometry, measurements of corneal radius, central corneal thickness, anterior chamber depth and white-to-white corneal diameter were acquired with IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany). The estimated scleral radius (11.2±0.3mm) was shown to be highly precise with a coefficient of variation of 0.4%. A statistically significant correlation between axial length and scleral radius (R 2 =0.957, p<0.001) was observed. Moreover, corneal radius (R 2 =0.420, p<0.001), anterior chamber depth (R 2 =0.141, p=0.039) and white-to-white corneal diameter (R 2 =0.146, p=0.036) have also shown statistically significant correlations with the scleral radius. Lastly, no correlation was observed comparing scleral radius to the central corneal thickness (R 2 =0.047, p=0.161). Three-dimensional topography of anterior eye acquired with Eye Surface Profiler together with a given estimate of the axial length, can be used to calculate the scleral radius with high precision. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Scleral contact lenses for the management of complicated ptosis.

PubMed

Katsoulos, Konstantinos; Rallatos, Gerasimos Livir; Mavrikakis, Ioannis

2018-06-01

To present the management of three patients suffering from ptosis of various etiologies, with scleral contact lenses. Three patients (five eyes) with ptosis resulting from levator dehiscence due to long-term rigid gas permeable contact lens wear for keratoconus, phthisis bulbi, and myopathy due to Kearns-Sayre syndrome were identified during a 2-year period. They were fitted with scleral contact lenses in order to provide cosmesis by lifting the upper eyelid with the bulk of the lens, and simultaneously provide vision correction where applicable. The scleral contact lenses provided comfortable wear, significantly improved cosmesis as both palpebral aperture and marginal reflex distance were increased, and visual acuity was also subjectively and objectively improved. Two of the patients opted for the scleral contact lenses, whereas the parents of the third patient, a 10-year-old girl with Kearns-Sayre syndrome, chose to undergo ptosis surgery due to handling issues of the scleral contact lenses. Scleral contact lenses can be a useful addition to the treatment option for patients with complicated ptosis.

Scleral electrocautery and its effects on choroid vessels: implications for subretinal fluid drainage during scleral buckling surgery.

PubMed

Roybal, C Nathaniel; Tsui, Irena; Sanfilippo, Christian; Hubschman, Jean-Pierre

2013-01-01

External drainage of subretinal fluid as part of a scleral buckling procedure rapidly restores the retinal pigment epithelium-neural retina interface in rhegmatogenous retinal detachments but carries the inherent risk of subretinal hemorrhage and retinal incarceration. The authors investigated variations to the technique to reduce the chance of subretinal hemorrhage originating from the choroid. A novel method for needle drainage using electrocautery of the sclerochoroidal layers before puncture was employed. The effect of 0% to 50% scleral electrocautery in a porcine model was investigated. A significant decrease in choroidal vessel diameter and choroidal vessel density at 40% electrocautery was demonstrated. Electrocautery without scleral cut-down before external drainage of subretinal fluid likely decreases the chance of subretinal hemorrhage by decreasing choroidal vascularity. Copyright 2013, SLACK Incorporated.

Combined Scleral Flap with Donor Scleral Patch Graft for Anterior Tube Placement in Glaucoma Drainage Device Surgery.

PubMed

Yu, Jea H; Nguyen, Chuck; Gallemore, Esmeralda; Gallemore, Ron P

2016-01-01

Purpose . To report a new technique for anterior placement of tubes for glaucoma drainage devices to reduce the risk of tube erosions. Methods . Retrospective review of select cases of Ahmed Valve surgery combined with the novel method of a limbal-based scleral flap covered by a scleral patch graft to cover the tube at the entrance through the limbus. Intraoperative and postoperative illustrations are shown to highlight the method of tube placement. Results . In this retrospective case series, 3 patients are presented illustrating the technique. Two had neovascular glaucoma and one had primary open-angle glaucoma (POAG). On average, intraocular pressure was reduced from 39 ± 14 mmHg to 15 ± 2 mmHg and the number of glaucoma medications was reduced from 4 ± 1 to 0. Preoperative and most recent visual acuities were hand-motion (HM) and HM, 20/60 and 20/50, and 20/70 and 20/30, respectively. Conclusion . The combination of a limbal-based scleral flap with scleral patch graft to cover the tube with glaucoma drainage devices may be an effective means to reduce erosion and protect against endophthalmitis.

Silicone Hydrogel and Rigid Gas-Permeable Scleral Lens Tear Exchange.

PubMed

Paugh, Jerry R; Chen, Elaine; Heinrich, Colton; Miller, Heidi; Gates, Tiffany; Nguyen, Andrew Loc; Edrington, Timothy; Weissman, Barry A

2018-03-01

To quantify tear elimination rate (ER) underneath silicone hydrogel (Si-Hy) and scleral gas permeable (GP) contact lenses (CLs). Subjects successfully using either well-fitting soft Si-Hy CLs or scleral GP CLs were recruited. Most scleral GP CL wearers had irregular corneas (e.g., keratoconus). An objective fluorometer measured decay of fluorescein isothiocyanate dextran dye signal (70 kD MW) from which the tear ER in %/min was calculated. For GP scleral lenses, the ER was determined for both the initial settling period and the 30- to 60-min period, and without lenses. All ERs were calculated from 5 to 30 min to avoid reflex tearing effects. Fourteen soft Si-Hy CL and 12 scleral GP CL wearers completed the study. The ER for the scleral GP CL wearers averaged 0.57 (±0.6) %/min for the 0- to 30-min and 0.42 (±0.5) %/min for the 30- to 60-min period (P=0.515). Non-CL wear tear ER in these same subjects averaged 34.17 (±15.9) %/min and was significantly different versus both scleral GP wear periods (both P values <0.001). The ER for the soft Si-Hy CL wearers, 5 to 30 min, averaged 6.09 (±2.8) %/min. Our data demonstrate significantly less ER in well-fit scleral GP CL wearers compared with soft Si-Hy CL wearers for both the settling and longer wear periods (both P values <0.001). Moreover, slightly greater tear exchange was observed during the scleral GP CL settling period than later, which may reflect a change over time in tear vault thickness.

Clinical Performance of a New Bitangential Mini-scleral Lens.

PubMed

Otten, Henny M; van der Linden, Bart J J J; Visser, Esther-Simone

2018-06-01

New bitangential mini-scleral lens designs provide a highly precise fit, follow the scleral shape, are comfortable to wear, and can correct residual astigmatism. This new scleral lens design complements the arsenal of medical contact lenses available to eye care practitioners. The aim of this study was to evaluate the subjective and objective performance of a new mini-scleral lens design with a bitangential periphery. In this observational study, data were collected for up to 15 months (median, 84 days; interquartile range, 76 days) from the left eyes of 133 patients fitted with this newly designed lens. Data were recorded during regular visits at Visser Contact Lens Practice's scleral lens clinics: diagnosis, clinical indication for scleral lenses, previous contact lens type, subjective performance, horizontal visible iris diameter, corrected distance visual acuity, and scleral lens fitting characteristics. The most common indication was keratoconus (45%), followed by irregular astigmatism (22%), keratoplasty (16.5%), ocular surface disease (13.5%), and other forms of irregular astigmatism (3%). The majority of patients (79%) scored comfort as either a 4 or 5 (out of 5), and 82% wore their lenses 12 hours or longer a day. Most lenses (81%) had a diameter of 16 mm (median, 16 mm; range, 15.5 to 17 mm) and were composed of Boston XO2 (46%), Menicon Z (44%), Boston XO (9%), or Boston Equalens II (1%). The median corrected distance visual acuity was 0.022 logarithm of the minimal angle of resolution (interquartile range, 0.155). The fitting characteristics revealed optimal values for centration and movement in 91% and 83%, respectively. Finally, the median stabilization axis was 50 degrees. New mini-scleral lenses with bitangential peripheral geometry yield satisfactory clinical results and good subjective performance and are therefore an effective option for managing patients who have irregular astigmatism or other corneal pathology.

Evaluation of posterior porcine sclera elasticity in situ as a function of IOP

NASA Astrophysics Data System (ADS)

Nair, Achuth; Wu, Chen; Singh, Manmohan; Liu, Chih Hao; Raghunathan, Raksha; Nguyen, Jennifer; Goh, Megan; Aglyamov, Salavat; Larin, Kirill V.

2018-02-01

The biomechanical properties of the sclera could provide key information regarding the progression and etiology of ocular diseases. For example, an elevated intraocular pressure is one of the most common risk factors for glaucoma and can cause pathological deformations in the tissues of the posterior eye, such as the sclera, potentially damaging these vital tissues. Previous work has evaluated scleral biomechanical response to global displacements with techniques such as inflation testing. However, these methods cannot provide localized biomechanical assessments. In this pilot work, we induce low amplitude (< 10 μm) elastic waves using acoustic radiation force in posterior scleral tissue of fresh porcine eyes (n=2) in situ. The wave propagation induced using an ultrasound transducer was detected across an 8 mm region using a phase-sensitive optical coherence elastography system (PhS-OCE). The elastographic measurements were taken at various artificially controlled intraocular pressures (IOP). The IOP was pre-cycled before being set to 10 mmHg for the first measurement. Subsequent measurements were taken at 20 mmHg and 30 mmHg for each sample. The results show an increase in the stiffness of the sclera as a function of IOP. Furthermore, we observed a variation in the elasticity based on direction, suggesting that the sclera has anisotropic biomechanical properties. Our results show that OCE is an effective method for evaluating the mechanical properties of the sclera, and reveals a new area for our future work.

The Influence of Scleral Flap Thickness, Shape, and Sutures on Intraocular Pressure (IOP) and Aqueous Humor Flow Direction in a Trabeculectomy Model.

PubMed

Samsudin, Amir; Eames, Ian; Brocchini, Steve; Khaw, Peng Tee

2016-07-01

Intraocular pressure and aqueous humor flow direction determined by the scleral flap immediately after trabeculectomy are critical determinants of the surgical outcome. We used a large-scale model to objectively measure the influence of flap thickness and shape, and suture number and position on pressure difference across the flap and flow of fluid underneath it. The model exploits the principle of dynamic and geometric similarity, so while dimensions were up to 30× greater than actual, the flow had similar properties. Scleral flaps were represented by transparent 0.8- and 1.6-mm-thick silicone sheets on an acrylic plate. Dyed 98% glycerin, representing the aqueous humor was pumped between the sheet and plate, and the equilibrium pressure measured with a pressure transducer. Image analysis based on the principle of dye dilution was performed using MATLAB software. The pressure drop across the flap was larger with thinner flaps, due to reduced rigidity and resistance. Doubling the surface area of flaps and reducing the number of sutures from 5 to 3 or 2 also resulted in larger pressure drops. Flow direction was affected mainly by suture number and position, it was less toward the sutures and more toward the nearest free edge of the flap. Posterior flow of aqueous humor was promoted by placing sutures along the sides while leaving the posterior edge free. We demonstrate a new physical model which shows how changes in scleral flap thickness and shape, and suture number and position affect pressure and flow in a trabeculectomy.

The Management of Refractory Dry Eye With Semi-Scleral Contact Lens.

PubMed

Yuksel, Erdem; Bilgihan, Kamil; Novruzlu, Şahin; Yuksel, Nilay; Koksal, Murat

2018-05-01

We presented a case of refractory dry eye management with semi-scleral contact lens. Dry eye was associated with facial nerve (cranial nerve VII) palsy as a result of cerebellopontine angle tumor surgery. She was treated with several topical treatments and punctal plug. Despite the treatments, her symptoms still persisted. Her ophthalmic examination revealed scleral exposure because of lagophthalmos, conjunctival hyperemia, corneal debris, scar, and diffuse punctate epitheliopathy on her right eye. Lissamine green staining showed diffuse conjunctival and corneal staining. Therapeutic semi-scleral lenses were fitted. The corneal findings were resolved and the quality of patient life was improved with the aid of semi-scleral lens after 3 months.

Scleral Lenses in the Management of Corneal Irregularity and Ocular Surface Disease.

PubMed

Shorter, Ellen; Harthan, Jennifer; Nau, Cherie B; Nau, Amy; Barr, Joseph T; Hodge, David O; Schornack, Muriel M

2017-09-29

To describe current practice patterns regarding the use of scleral lens therapy in the management of corneal irregularity and ocular surface disease among eye care providers who fit scleral lenses. The Scleral Lenses in Current Ophthalmic Practice: an Evaluation (SCOPE) study group conducted an electronic survey of eye care providers from January 15 to March 31, 2015. Respondents ranked management options for corneal irregularity in the order in which they would generally consider their use. Respondents also ranked options for the management of ocular surface disease in the order in which they would use each of the treatments. Results for each option were analyzed as percentage first-place ranking; percentage first-, second-, or third-place ranking; and mean rank score. Survey responses were obtained from 723 providers who had fit 5 or more scleral lenses. Of these respondents, 629 ranked options for management of corneal irregularity and 612 ranked options for management of ocular surface disease. Corneal rigid gas-permeable lenses were the first option for management of corneal irregularity for 44% of respondents, and scleral lenses were the first option for 34% of respondents. Lubricant drops were the first therapeutic recommendation for ocular surface disease for 84% of respondents, and scleral lenses were ranked first by 6% of respondents. Scleral lenses rank second only to corneal rigid gas-permeable lenses for management of corneal irregularity. Scleral lenses are generally considered after other medical intervention and before surgery for the management of ocular surface disease.

The ultrastructure of rabbit sclera after scleral crosslinking with riboflavin and blue light of different intensities.

PubMed

Karl, Anett; Makarov, Felix N; Koch, Christian; Körber, Nicole; Schuldt, Carsten; Krüger, Martin; Reichenbach, Andreas; Wiedemann, Peter; Bringmann, Andreas; Iseli, Hans Peter; Francke, Mike

2016-08-01

We aimed to determine the ultrastructural changes of collagen fibrils and cells in the rabbit sclera after scleral crosslinking using riboflavin and blue light of different intensities. Scleral crosslinking is known to increase scleral stiffness and may inhibit the axial elongation of progressive myopic eyes. The equatorial parts of the sclera of one eye of six adult albino rabbits were treated with topical riboflavin solution (0.5 %) followed by irradiation with blue light (200, 400, 650 mW/cm(2)) for 20 min. After 3 weeks, the ultrastructure of scleral cells and the abundance of small- (10-100 nm) and large-diameter (>100 nm) collagen fibrils in fibril bundles of different scleral layers were examined with electron microscopy. In the scleral stroma of control eyes, the thickness of collagen fibrils showed a bimodal distribution. The abundance of small-diameter collagen fibrils decreased from the inner towards the outer sclera, while the amount of large-diameter fibrils and the scleral collagen content did not differ between different stroma layers. Treatment with riboflavin and blue light at 200 mW/cm(2) did not induce ultrastructural changes of cells and collagen fibrils in the scleral stroma. Treatment with blue light of higher intensities induced scleral cell activation in a scleral layer-dependent manner. In addition, outer scleral layers contained phagocytes that engulfed collagen fibrils and erythrocytes. Blue light of the highest intensity induced a reduction of the scleral collagen content, a decreased abundance of large-diameter collagen fibrils, and an increased amount of small-diameter fibrils in the whole scleral stroma. The data indicate that in rabbits, scleral crosslinking with riboflavin and blue light of 200 mW/cm(2) for 20 min is relatively safe and does not induce ultrastructural alterations of scleral cells and of the collagen composition of the scleral stroma. Irradiation with blue light of intensities between 200 and 400 mW/cm(2

Damage threshold in adult rabbit eyes after scleral cross-linking by riboflavin/blue light application.

PubMed

Iseli, Hans Peter; Körber, Nicole; Karl, Anett; Koch, Christian; Schuldt, Carsten; Penk, Anja; Liu, Qing; Huster, Daniel; Käs, Josef; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike

2015-10-01

Several scleral cross-linking (SXL) methods were suggested to increase the biomechanical stiffness of scleral tissue and therefore, to inhibit axial eye elongation in progressive myopia. In addition to scleral cross-linking and biomechanical effects caused by riboflavin and light irradiation such a treatment might induce tissue damage, dependent on the light intensity used. Therefore, we characterized the damage threshold and mechanical stiffening effect in rabbit eyes after application of riboflavin combined with various blue light intensities. Adult pigmented and albino rabbits were treated with riboflavin (0.5 %) and varying blue light (450 ± 50 nm) dosages from 18 to 780 J/cm(2) (15 to 650 mW/cm(2) for 20 min). Scleral, choroidal and retinal tissue alterations were detected by means of light microscopy, electron microscopy and immunohistochemistry. Biomechanical changes were measured by shear rheology. Blue light dosages of 480 J/cm(2) (400 mW/cm(2)) and beyond induced pathological changes in ocular tissues; the damage threshold was defined by the light intensities which induced cellular degeneration and/or massive collagen structure changes. At such high dosages, we observed alterations of the collagen structure in scleral tissue, as well as pigment aggregation, internal hemorrhages, and collapsed blood vessels. Additionally, photoreceptor degenerations associated with microglia activation and macroglia cell reactivity in the retina were detected. These pathological alterations were locally restricted to the treated areas. Pigmentation of rabbit eyes did not change the damage threshold after a treatment with riboflavin and blue light but seems to influence the vulnerability for blue light irradiations. Increased biomechanical stiffness of scleral tissue could be achieved with blue light intensities below the characterized damage threshold. We conclude that riboflavin and blue light application increased the biomechanical stiffness of scleral tissue at

Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear.

PubMed

Compañ, Vicente; Aguilella-Arzo, Marcel; Edrington, Timothy B; Weissman, Barry A

2016-11-01

The main goal of this current work is to use an updated calculation paradigm, and updated boundary conditions, to provide theoretical guidelines to assist the clinician whose goal is to improve his or her scleral gas permeable (GP) contact lens wearing patients' anterior corneal oxygen supply. Our model uses a variable value of corneal oxygen consumption developed through Monod equations that disallows negative oxygen tensions within the stroma to predict oxygen tension at the anterior corneal surface of scleral GP contact lens wearing eyes, and to describe oxygen tension and flux profiles, for various boundary conditions, through the lens, tears, and cornea. We use several updated tissue and boundary parameters in our model. Tear exchange with GP scleral lenses is considered nonexistent in this model. The majority of current scleral GP contact lenses should produce some levels of corneal hypoxia under open eye conditions. Only lenses producing the thinnest of tear vaults should result in anterior corneal surface oxygen tensions greater than a presumed critical oxygen tension of 100 mmHg. We also find that corneal oxygen tension and flux are each more sensitive to modification in tear vault than to changes in lens oxygen permeability, within the ranges of current clinical manipulation. Our study suggests that clinicians would be prudent to prescribe scleral GP lenses manufactured from higher oxygen permeability materials and especially to fit without excessive corneal clearance.

Scleral fixation of one piece intraocular lens by injector implantation

PubMed Central

Can, Ertuğrul; Başaran, Reşat; Gül, Adem; Birinci, Hakkı

2014-01-01

Aim of Study: With an ab-interno technique of transscleral suturing of current one-piece posterior chamber intraocular lenses (PC IOLs) by injector implantation in the absence of capsular support, we aimed to demonstrate the possibility of the implantation of one-piece acrylic PC IOLs that might be produced in the future for only scleral fixation through small clear corneal incision. Materials and Methods: Case report and literature review. Results: This procedure has been performed in eight aphakic eyes with four different types of IOLs. Good centration was achieved with minimal technical effort. All patients had well-centered and stable lenses postoperatively during 9-18 months follow-up. Conclusion: We managed to decrease the risks of surgical trauma and intricate surgical maneuvers requirement. With this technique, excessive fluid leakage and consecutive hypotony can be minimized. PMID:25230961

Erosion and intrusion of silicone rubber scleral buckle. Presentation and management.

PubMed

Nguyen, Q D; Lashkari, K; Hirose, T; Pruett, R C; McMeel, J W; Schepens, C L

2001-01-01

To describe the clinical presentation and management of erosion and intrusion of silicone rubber implants that are used in scleral buckling procedures for the treatment of retinal detachment. The authors identified four patients from their practices during the last 20 years (1978-1998) who had erosion or intrusion of silicone rubber scleral buckles that were used to manage retinal detachment. Approximately 4400 scleral buckling procedures were performed during this period. A retrospective review of the medical records of all patients was performed. Factors that influenced management decisions concerning the intruding buckle are emphasized. All four patients had myopia. The interval between placement of the scleral buckle and development of intrusion ranged from 1 to 20 years. The buckles were intrascleral in three cases and episcleral in one. Recurrent detachment and vitreous hemorrhage were indications for surgical intervention in three cases. After the surgical removal of buckling elements, visual acuity stabilized in all patients and the retina remained attached in all cases. Erosion and intrusion of scleral buckle are rare complications of scleral buckling procedures. The intruding buckle may be left intact unless there is significant threat to the integrity of ocular structures, recurrent detachment, or hemorrhage. Manipulation of the encircling band or buckle does not necessarily alter the visual acuity or the status of the retina.

Viscoelastic properties of the posterior eye of normal subjects, patients with age-related macular degeneration, and pigs.

PubMed

Zhang, Zhen Huan; Pan, Meng Xin; Cai, Jia Tong; Weiland, James D; Chen, Kinon

2018-03-26

The purpose of this study is to measure, characterize, and compare the viscoelastic properties of the posterior eye of advanced dry age-related macular degeneration (AMD) patients, age-matched normal subjects, and pigs (3 groups). Ten horizontal and ten vertical strips of the macula retina and the underneath choroid and sclera were obtained for each group, respectively. They were examined by incremental stress-relaxation cycles in body-temperature saline. Mechanical response was characterized by the quasi-linear viscoelastic model. All the tissues were shown to be nonlinear viscoelastic. Stiffening and isotropization, increased relaxation, and softening and isotropization were found in AMD retina, choroid, and sclera, respectively, which are the mechanical features of the atherosclerotic process. The patients' medical records were in accordance with epidemiological studies indicating a relationship between the advanced AMD and atherosclerotic vascular disease (ASVD). Moreover, many differences were found between the viscoelastic properties of porcine and normal human retina, choroid, and sclera. The results suggest that AMD is associated with ASVD through a mechanism involving abnormal retinal, choroidal, and scleral mechanics similar to those seen in the atherosclerotic process. Moreover, researchers should be aware of mechanical differences when using porcine posterior eyes as a substitute for human posterior eyes. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018. © 2018 Wiley Periodicals, Inc.

Hydrogel Ring for Topical Drug Delivery to the Ocular Posterior Segment.

PubMed

Shikamura, Yuko; Yamazaki, Yoshiko; Matsunaga, Toru; Sato, Takao; Ohtori, Akira; Tojo, Kakuji

2016-05-01

To investigate the efficacy of a topical hydrogel ring for drug delivery to the posterior segment of the rabbit eye. Novel hydrogel corneal lenses (CL), scleral/corneal lenses (S/CL), and rings were prepared using poly(hydroxyethyl methacrylate). The devices were immersed in 0.3% ofloxacin ophthalmic solution (OOS) to homogeneously distribute the drug throughout the hydrogel. The medicated CL, S/CL, Ring 1 (standard ring), or Ring 2 (shape-optimized ring) was applied to the surface of the cornea, cornea/bulbar conjunctiva, or bulbar conjunctiva of albino rabbits, respectively. Medicated rings did not touch the corneal surface. In another group, one OOS drop was administered to the eye. After 0.25-8 hours, the hydrogel devices were removed and ocular tissues were harvested. High-performance liquid chromatography (HPLC) was used to measure the ofloxacin concentration in the devices and tissues. The drug concentrations in the posterior segment tissues were compared among ofloxacin delivery methods. One hour after placement, eyes treated with Ring 1 or S/CL had markedly higher ofloxacin levels in the posterior segment tissues (conjunctiva, sclera, and retina/choroid) than eyes treated with topical OOS or a CL. Lower levels of ofloxacin were found in anterior segment tissues (cornea and aqueous humor) in eyes treated with Ring 1 compared to those treated with S/CL. Ring 2 most effectively delivered ofloxacin to the retina/choroid. The tissue ofloxacin concentration in the fellow eye was markedly lower than the eye treated with Ring 2. Our results suggest that hydrogel rings are effective in delivering topical ophthalmic drugs to the posterior segment. The drugs are most likely delivered via the transconjunctival/scleral route by lateral diffusion across the bulbar conjunctiva and through the sclera. Systemic drug delivery to the posterior segment is minimal.

A rare case of scleral buckle infection with Curvularia species.

PubMed

Singh, Shalini; Shrivastav, Ankita; Agarwal, Manisha; Gandhi, Arpan; Mayor, Rahul; Paul, Lagan

2018-02-09

Scleral buckling is an established modality of treating retinal detachment. Being an external implant the buckle may be prone to infections. We report such a case with a delayed presentation and a rare etiology. A 45 year old male presented with redness, foreign body sensation and discharge for one month in his right eye. The patient had undergone a retinal detachment surgery elsewhere 14 years back without any visual gain. Right eye demonstrated no perception of light and the best corrected visual acuity in the left eye was 6/6, N6. On downgaze an exposed and anteriorly displaced scleral buckle was identified with black deposits and mucopurulent material overlying the buckle. Scleral buckle removal was done. On microbiological examination Curvularia species was identified. Successful treatment with antifungals was done. Scleral buckle infection with dematiaceous fungi is a rare occurrence. To the best of our knowledge this is the first case report describing a buckle infection caused by the curvularia species.

Scleral patch grafts in the management of uveal and ocular surface tumors.

PubMed

Barman, Manabjyoti; Finger, Paul T; Milman, Tatyana

2012-12-01

To evaluate the outcome of scleral patch grafts in a series of patients undergoing management for uveal and ocular surface tumors. Case series. Ten patients underwent scleral patch grafting. Five patients had uveal melanoma with extrascleral extension, 2 patients had scleromalacia secondary to plaque radiotherapy for uveal melanoma, 2 patients had suspicious uveoscleral nevi, and 1 patient had invasive conjunctival squamous cell carcinoma with scleral necrosis. Retrospective, interventional, noncomparative chart review of patients undergoing treatment for ocular tumors followed by scleral grafts in a tertiary eye care center in the United States between September 2003 and January 2011. Sclera was reconstructed with allogenic scleral grafts. Clinical observations were performed after grafting. Structural integrity, appearance, and stability of the grafts. Ten patients were reviewed. All melanoma cases received plaque radiotherapy with palladium 103. The cases with nevi and squamous cell carcinoma underwent local resection with cryotherapy as primary treatment. In 8 cases, scleral grafting was performed as part of the initial surgery. In all of these cases, satisfactory anatomic and functional outcomes were achieved. In 2 cases with scleromalacia secondary to radiotherapy for uveal melanoma, grafts were placed several years after the initial treatment. In these 2 cases, one showed signs of graft retraction, whereas another showed graft thinning. No patients experienced graft infection, rejection, or tumor recurrence. In this series, scleral grafts were well accepted when placed as part of the primary tumor management despite synchronous radiotherapy, scleral resection, or cryotherapy. Grafting was less successful when performed as a late procedure for radiation-induced scleromalacia. The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All

Trabeculectomy augmented with mitomycin C application under the scleral flap

PubMed Central

Beatty, S; Potamitis, T; Kheterpal, S; O'Neill, E

1998-01-01

AIM—The authors investigated the safety and intraocular pressure (IOP) lowering effectiveness of trabeculectomy augmented with mitomycin C application beneath the scleral flap, and assessed the influence of preoperative risk factors on the surgical outcome.
METHODS—A retrospective study of 72 consecutive high risk eyes undergoing trabeculectomy with adjunctive mitomycin C (0.2 mg/ml) applied under the scleral flap for 5 minutes was performed. Each eye was ascribed a score based on the number of preoperative risk factors, and categorised into one of three risk factor groups. Success was described as unqualified where IOP was ⩽ 21 mm Hg without medication and qualified where antiglaucomatous therapy was required to maintain it at such a level. A life table analysis of IOP control was calculated.
RESULTS—The mean IOP (SD) fell from a preoperative level of 28.4 (6.9) to a level of 16.63 (8.06) mm Hg at the last follow up (paired Student's t test: p< 0.0001). Fifty two eyes (72%) were classed as unqualified successes. The survival rates did not differ significantly between different risk factor groups (log rank test: χ2 = 0.967, p>0.1). The incidence of postoperative complications compared favourably with reports of mitomycin C application between Tenon's capsule and the undissected scleral bed.
CONCLUSION—The results illustrate that mitomycin C applied beneath the scleral flap during trabeculectomy in high risk eyes is associated with a success rate comparable to other modes of application. The incidence of potentially serious complications such as conjunctival wound leak and prolonged hypotony was lower than previously published data reporting sub-Tenon's administration of mitomycin C. The number and nature of preoperative risk factors do not appear to influence the surgical outcome. A possible mechanism of action is proposed.

 Keywords: glaucoma; intraocular pressure; trabeculectomy; mitomycin C PMID:9640188

Effects of Peripapillary Scleral Stiffening on the Deformation of the Lamina Cribrosa

PubMed Central

Coudrillier, Baptiste; Campbell, Ian C.; Read, A. Thomas; Geraldes, Diogo M.; Vo, Nghia T.; Feola, Andrew; Mulvihill, John; Albon, Julie; Abel, Richard L.; Ethier, C. Ross

2016-01-01

Purpose Scleral stiffening has been proposed as a treatment for glaucoma to protect the lamina cribrosa (LC) from excessive intraocular pressure–induced deformation. Here we experimentally evaluated the effects of moderate stiffening of the peripapillary sclera on the deformation of the LC. Methods An annular sponge, saturated with 1.25% glutaraldehyde, was applied to the external surface of the peripapillary sclera for 5 minutes to stiffen the sclera. Tissue deformation was quantified in two groups of porcine eyes, using digital image correlation (DIC) or computed tomography imaging and digital volume correlation (DVC). In group A (n = 14), eyes were subjected to inflation testing before and after scleral stiffening. Digital image correlation was used to measure scleral deformation and quantify the magnitude of scleral stiffening. In group B (n = 5), the optic nerve head region was imaged using synchrotron radiation phase-contrast microcomputed tomography (PC μCT) at an isotropic spatial resolution of 3.2 μm. Digital volume correlation was used to compute the full-field three-dimensional deformation within the LC and evaluate the effects of peripapillary scleral cross-linking on LC biomechanics. Results On average, scleral treatment with glutaraldehyde caused a 34 ± 14% stiffening of the peripapillary sclera measured at 17 mm Hg and a 47 ± 12% decrease in the maximum tensile strain in the LC measured at 15 mm Hg. The reduction in LC strains was not due to cross-linking of the LC. Conclusions Peripapillary scleral stiffening is effective at reducing the magnitude of biomechanical strains within the LC. Its potential and future utilization in glaucoma axonal neuroprotection requires further investigation. PMID:27183053

Scleral fibroblast response to experimental glaucoma in mice

PubMed Central

Tezel, Gülgün; Cone-Kimball, Elizabeth; Steinhart, Matthew R.; Jefferys, Joan; Pease, Mary E.; Quigley, Harry A.

2016-01-01

Purpose To study the detailed cellular and molecular changes in the mouse sclera subjected to experimental glaucoma. Methods Three strains of mice underwent experimental bead-injection glaucoma and were euthanized at 3 days and 1, 3, and 6 weeks. Scleral protein expression was analyzed with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) using 16O/18O labeling for quantification in 1- and 6-week tissues. Sclera protein samples were also analyzed with immunoblotting with specific antibodies to selected proteins. The proportion of proliferating scleral fibroblasts was quantified with Ki67 and 4’,6-diamidino-2-phenylindole (DAPI) labeling, and selected proteins were studied with immunohistochemistry. Results Proteomic analysis showed increases in molecules involved in integrin-linked kinase signaling and actin cytoskeleton signaling pathways at 1 and 6 weeks after experimental glaucoma. The peripapillary scleral region had more fibroblasts than equatorial sclera (p=0.001, n=217, multivariable regression models). There was a sixfold increase in proliferating fibroblasts in the experimental glaucoma sclera at 1 week and a threefold rise at 3 and 6 weeks (p=0.0005, univariate regression). Immunoblots confirmed increases for myosin, spectrin, and actinin at 1 week after glaucoma. Thrombospondin-1 (TSP-1), HINT1, vimentin, actinin, and α-smooth muscle actin were increased according to immunohistochemistry. Conclusions Scleral fibroblasts in experimental mouse glaucoma show increases in actin cytoskeleton and integrin-related signaling, increases in cell division, and features compatible with myofibroblast transition. PMID:26900327

Scleral Shape and Its Correlations With Corneal Astigmatism.

PubMed

Consejo, Alejandra; Rozema, Jos J

2018-03-06

To assess the correlation between the scleral shape and corneal astigmatism. Twenty-two participants (11 nonastigmatic and 11 astigmatic) aged from 19 to 36 years and with no previous ocular surgeries were included in this study. Three-dimensional (3D) corneoscleral maps from both eyes (44 eyes) were acquired using a corneoscleral topographer (Eye Surface Profiler). Each 3D map was split into 13 concentric annuli, each 0.5-mm wide, starting at 1.0-mm radius from the corneal apex to the scleral periphery at 7.5 mm from the apex. Each ring was fitted to a quadratic function of the radial distance to the apex, to calculate the elevation difference between the raw data and the fitting surface ring. For each ring, the resulting elevation difference between the original and fit data profile was fit to a sum of sine function. Decentration and astigmatic terms obtained from the sinusoidal fit were analyzed and compared between nonastigmatic and astigmatic groups. In astigmatic eyes, corneal and scleral asymmetry are highly correlated, but both appear independent of each other in nonastigmatic eyes. No significant difference between astigmatic and nonastigmatic eyes was found for the decentration term [P > 0.05/N (Bonferroni)], whereas for the astigmatic component, the differences were statistically significant [P < 0.05/N (Bonferroni)]. Corneal and scleral shapes are correlated in astigmatic eyes, which suggests that astigmatism is not restricted to the cornea but should rather be considered a property of the entire eye globe.

A novel bioerodible deep scleral lamellar cyclosporine implant for uveitis.

PubMed

Gilger, Brian C; Salmon, Jacklyn H; Wilkie, David A; Cruysberg, Lars P J; Kim, Jonghyeon; Hayat, Matt; Kim, Hyuncheol; Kim, Stephanie; Yuan, Peng; Lee, Susan S; Harrington, Susan M; Murray, Patrick R; Edelhauser, Henry F; Csaky, Karl G; Robinson, Michael R

2006-06-01

To determine the feasibility, safety, and effectiveness of an episcleral or deep scleral lamellar sustained release cyclosporine (CsA) device in a naturally occurring animal model of uveitis. A two-compartment perfusion chamber was used to assess in vitro human and equine scleral permeability of fluorescein, dexamethasone-fluorescein, or CsA. A biodegradable, matrix-reservoir CsA implant was designed, and release rates of CsA were determined in vitro. Tissue CsA levels were measured in eyes with the implant. Horses with equine recurrent uveitis (ERU) received episcleral or deep scleral lamellar CsA implants and were monitored for up to 3 years. Dexamethasone-fluorescein and CsA penetrated the in vitro equine sclera poorly; however, low but detectable levels of CsA were detected intraocularly in vivo. The implant placed episclerally failed to control inflammatory episodes in ERU. CsA implants placed in the deep sclera adjacent to the suprachoroidal space resulted in high levels of CsA in most ocular tissues. In clinical equine patients with ERU, frequency of uveitic flare-ups was significantly decreased after implantation of a deep scleral lamellar CsA implant. Diffusion of CsA across the sclera from the episcleral space was not a feasible method of drug delivery to the equine eye. However, placing a deep scleral lamellar CsA implant adjacent to the suprachoroidal space was effective in achieving therapeutic ocular drug concentrations and controlling uveitis in horses with ERU.

Short-term Effect of Scleral Lens on the Dry Eye Biomarkers in Keratoconus.

PubMed

Carracedo, Gonzalo; Blanco, Maria Serramito; Martin-Gil, Alba; Zicheng, Wang; Alvarez, Jesús Carballo; Pintor, Jesús

2016-02-01

To evaluate the most important signs of dry eye, such as osmolarity, inflammation, and diadenosine tetraphosphate (Ap(4)A) concentration before and after wearing scleral lenses for 8 h in keratoconus patients. A pilot, experimental, short-term study involved 26 keratoconus patients (average age, 36.95 ± 8.95 years). They voluntarily enrolled in the study at the Optometry Clinic of the Faculty of Optics and Optometry in the University Complutense of Madrid. They were divided into two groups: patients with intrastromal corneal ring, the ICRS group, and patients without ICRS, the keratoconus (KC) group. Ocular Surface Disease Index questionnaire, the Schirmer test without anesthesia, tear break-up time, matrix metalloproteinase 9 (MMP-9) concentration, osmolarity, and Ap4A concentration were evaluated before and after wearing a scleral lens for 8 h. The patients wore the scleral lenses from 6 to 9 h, with a mean of 7.59 ± 0.73 h. The mean scleral lens sag for all patients was 4310 ± 166.31 μm, ranging from 4200 μm to 4800 μm. No significant changes in the Schirmer test and tear break-up time were found for either group. Ocular Surface Disease Index scores were statistically lower after wearing scleral lenses for both groups (p < 0.05). A significantly lower osmolarity and a significant rise of MMP-9 concentration after wearing scleral lenses were found in both groups (p < 0.05). Diadenosine tetraphosphate concentration was lower after wearing the scleral lens in the KC group (p < 0.05) but no significant difference was found for the ICRS group (p > 0.05). Short-term scleral lens wearing improves the symptomatology and some signs of dry eye, such as osmolarity and Ap4A concentration. The increase of MMP-9 concentration could be caused by tear film stagnation and use of preserved saline.

Surface coverage with single vs. multiple gaze surface topography to fit scleral lenses.

PubMed

DeNaeyer, Gregory; Sanders, Donald R; Farajian, Timothy S

2017-06-01

To determine surface coverage of measurements using the sMap3D ® corneo-scleral topographer in patients presenting for scleral lens fitting. Twenty-five eyes of 23 scleral lens patients were examined. Up-gaze, straight-gaze, and down-gaze positions of each eye were "stitched" into a single map. The percentage surface coverage between 10mm and 20mm diameter circles from corneal center was compared between the straight-gaze and stitched images. Scleral toricity magnitude was calculated at 100% coverage and at the same diameter after 50% of the data was removed. At a 10mm diameter from corneal center, the straight-gaze and stitched images both had 100% coverage. At the 14, 15, 16, 18 and 20mm diameters, the straight-gaze image only covered 68%, 53%, 39%, 18%, and 6% of the ocular surface diameters while the stitched image covered 98%, 96%, 93%, 75%, and 32% respectively. In the case showing the most scleral coverage at 16mm (straight-gaze), there was only 75% coverage (straight-gaze) compared to 100% (stitched image); the case with the least coverage had 7% (straight gaze) and 92% (stitched image). The 95% limits of agreement between the 50% and 100% coverage scleral toricity was between -1.4D (50% coverage value larger) and 1.2D (100% coverage larger), a 2.6D spread. The absolute difference between 50% to 100% coverage scleral toricity was ≥0.50D in 28% and ≥1.0D in 16% of cases. It appears that a single straight-gaze image would introduce significant measurement inaccuracy in fitting scleral lenses using the sMap3D while a 3-gaze stitched image would not. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Experimental scleral cross-linking increases glaucoma damage in a mouse model

PubMed Central

Kimball, Elizabeth C.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary E.; Oglesby, Ericka N.; Oveson, Brian C.; Quigley, Harry A.

2014-01-01

The purpose of this study was to assess the effect of a scleral cross-linking agent on susceptibility to glaucoma damage in a mouse model. CD1 mice underwent 3 subconjunctival injections of 0.5 M glyceraldehyde (GA) in 1 week, then had elevated intraocular pressure (IOP) induced by bead injection. Degree of cross-linking was measured by enzyme-linked immunosorbent assay (ELISA), scleral permeability was measured by fluorescence recovery after photobleaching (FRAP), and the mechanical effects of GA exposure were measured by inflation testing. Control mice had buffer injection or no injection in 2 separate glaucoma experiments. IOP was monitored by Tonolab and retinal ganglion cell (RGC) loss was measured by histological axon counting. To rule out undesirable effects of GA, we performed electroretinography and detailed histology of the retina. GA exposure had no detectable effects on RGC number, retinal structure or function either histologically or electrophysiologically. GA increased cross-linking of sclera by 37% in an ELISA assay, decreased scleral permeability (FRAP, p = 0.001), and produced a steeper pressure—strain behavior by in vitro inflation testing. In two experimental glaucoma experiments, GA-treated eyes had greater RGC axon loss from elevated IOP than either buffer-injected or control eyes, controlling for level of IOP exposure over time (p = 0.01, and 0.049, multivariable regression analyses). This is the first report that experimental alteration of the sclera, by cross-linking, increases susceptibility to RGC damage in mice. PMID:25285424

Corneal oedema in a unilateral corneal graft patient induced by high Dk mini-scleral contact lens.

PubMed

Guillon, Natalie C; Godfrey, Andrew; Hammond, David S

2018-05-24

Scleral contact lenses are increasingly becoming accepted as the method of choice for visual correction of the irregular cornea. As such, cases have surfaced which demonstrate complications arising from mini-scleral lenses. Identification of these issues and adjusting fitting techniques accordingly is necessary for reducing the risks associated with mini-scleral lens wear. A 58 year old Caucasian female was referred for rigid gas permeable contact lens fitting for correction of right irregular astigmatism post penetrating keratoplasty. After four months of successful mini-scleral contact lens wear, the patient experienced a graft rejection episode and treated accordingly, then refit with a new mini-scleral lens. Five months after the lens refit, the patient presented with complaints of hazy vision, and a diagnosis of lens-induced corneal oedema made. Increased awareness of the potential complications of mini-scleral lenses is necessary to encourage and enforce mini-scleral lens fitting techniques that meet the requirements of minimum vault but adequate protection of the compromised cornea. Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Scleral birefringence as measured by polarization-sensitive optical coherence tomography and ocular biometric parameters of human eyes in vivo.

PubMed

Yamanari, Masahiro; Nagase, Satoko; Fukuda, Shinichi; Ishii, Kotaro; Tanaka, Ryosuke; Yasui, Takeshi; Oshika, Tetsuro; Miura, Masahiro; Yasuno, Yoshiaki

2014-05-01

The relationship between scleral birefringence and biometric parameters of human eyes in vivo is investigated. Scleral birefringence near the limbus of 21 healthy human eyes was measured using polarization-sensitive optical coherence tomography. Spherical equivalent refractive error, axial eye length, and intraocular pressure (IOP) were measured in all subjects. IOP and scleral birefringence of human eyes in vivo was found to have statistically significant correlations (r = -0.63, P = 0.002). The slope of linear regression was -2.4 × 10(-2) deg/μm/mmHg. Neither spherical equivalent refractive error nor axial eye length had significant correlations with scleral birefringence. To evaluate the direct influence of IOP to scleral birefringence, scleral birefringence of 16 ex vivo porcine eyes was measured under controlled IOP of 5-60 mmHg. In these ex vivo porcine eyes, the mean linear regression slope between controlled IOP and scleral birefringence was -9.9 × 10(-4) deg/μm/mmHg. In addition, porcine scleral collagen fibers were observed with second-harmonic-generation (SHG) microscopy. SHG images of porcine sclera, measured on the external surface at the superior side to the cornea, showed highly aligned collagen fibers parallel to the limbus. In conclusion, scleral birefringence of healthy human eyes was correlated with IOP, indicating that the ultrastructure of scleral collagen was correlated with IOP. It remains to show whether scleral collagen ultrastructure of human eyes is affected by IOP as a long-term effect.

Biaxial Mechanical Testing of Posterior Sclera using High-Resolution Ultrasound Speckle Tracking for Strain Measurements

PubMed Central

Cruz-Perez, Benjamin; Tang, Junhua; Morris, Hugh J.; Palko, Joel R.; Pan, Xueliang; Hart, Richard T.; Liu, Jun

2014-01-01

This study aimed to characterize the mechanical responses of the sclera, the white outer coat of the eye, under equal-biaxial loading with unrestricted shear. An ultrasound speckle tracking technique was used to measure tissue deformation through sample thickness, expanding the capabilities of surface strain techniques. Eight porcine scleral samples were tested within 72 hours postmortem. High resolution ultrasound scans of scleral cross-sections along the two loading axes were acquired at 25 consecutive biaxial load levels. An additional repeat of the biaxial loading cycle was performed to measure a third normal strain emulating a strain gauge rosette for calculating the in-plane shear. The repeatability of the strain measurements during identical biaxial ramps was evaluated. A correlation-based ultrasound speckle tracking algorithm was used to compute the displacement field and determine the distributive strains in the sample cross-sections. A Fung type constitutive model including a shear term was used to determine the material constants of each individual specimen by fitting the model parameters to the experimental stress-strain data. A non-linear stress-strain response was observed in all samples. The meridian direction had significantly larger strains than the circumferential direction during equal-biaxial loadings (P’s<0.05). The stiffness along the two directions were also significantly different (P=0.02) but highly correlated (R2=0.8). These results showed that the mechanical properties of the porcine sclera were nonlinear and anisotropic under biaxial loading. This work has also demonstrated the feasibility of using ultrasound speckle tracking for strain measurements during mechanical testing. PMID:24438767

Effect of Biodegradable Scleral Plugs Containing Curcumin on Proliferative Vitreoretinopathy.

PubMed

Zhang, Jun; Zhou, Nalei; Zhang, Bin; Ma, Jingxue

2018-01-01

This study aimed to explore the inhibitory effect of biodegradable scleral plugs containing curcumin on rabbits with proliferative vitreoretinopathy (PVR). The biodegradable scleral plugs containing curcumin were prepared by dissolving PLGA [poly(lactide-co-glycolide)] and curcumin. In total, 30 rabbits were divided into 2 groups: the model group received a vitreous injection of self-blood, and the treatment group received a vitreous injection of self-blood plus biodegradable scleral implants containing 1.5 mg of curcumin. On days 1, 3, 7, 14, 21, and 28 after the operation, clinical observations and PVR classifications were performed. Then, after vitreous samples were collected, different cytokines were detected using antibody chip technology. The scleral plug was 5 mm in length and 1 mm in diameter. Clinical observation showed marked inflammation in the model group. The development grade of PVR in the treatment group was lower than that in the model group (p < 0.05). The outcome of antibody chip technology showed that the expression levels of IL-1α, IL-1β, IL-8, leptin, MMP-9, NCAM, and TNF-α in the treatment group at different time points were significantly lower than those in the model group (p < 0.05). Curcumin might have great potential as a therapeutic agent for PVR by inhibiting various inflammatory factors. © 2017 S. Karger AG, Basel.

Irregular Corneas: Improve Visual Function With Scleral Contact Lenses.

PubMed

de Luis Eguileor, Beatriz; Etxebarria Ecenarro, Jaime; Santamaria Carro, Alaitz; Feijoo Lera, Raquel

2018-05-01

To assess visual function in patients with irregular cornea who do not tolerate gas permeable (GP) corneal contact lenses and are fitted with GP scleral contact lenses (Rose K2 XL). In this prospective study, we analyzed 15 eyes of 15 patients who did not tolerate GP corneal contact lenses and were fitted with scleral contact lenses (Rose K2 XL). We assessed visual function using visual acuity and the visual function index (VF-14); we used the VF-14 as an indicator of patient satisfaction. The measurements were taken with the optical correction used before and 1 month after the fitting of the Rose K2 XL contact lenses. We also recorded the number of hours lenses had been worn over the first month. Using Rose K2 XL contact lenses, visual acuity was 0.06±0.07 logMAR. In all cases, visual acuity had improved compared with the measurement before fitting the lenses (0.31±0.18 logMAR; P=0.001). VF-14 scores were 72.74±12.38 before fitting of the scleral lenses, and 89.31±10.87 after 1 month of lens use (P=0.003). Patients used these scleral lenses for 9.33±2.99 comfortable hours of wear. Both visual acuity and VF-14 may improve after fitting Rose K2 XL contact lenses in patients with irregular corneas. In addition, in our patients, these lenses can be worn for a longer period than GP corneal contact lenses.

An investigation of CO2 laser scleral buckling using moiré interferometry.

PubMed

Maswadi, Saher M; Dyer, Peter E; Verma, Dinesh; Jalabi, Wadah; Dave, Dinesh

2002-01-01

To demonstrate suitability of moiré interferometry to assess and quantify laser-induced shrinkage of scleral collagen for buckling procedures. Scleral buckling of human cadaver eyes was investigated using a Coherent Ultrapulse CO2 laser. Projection moiré interferometry was employed to determine the out-of plane displacement produced by laser exposure, and in-situ optical microscopy of reference markers on the eye was used to measure in-plane shrinkage. Measurements based on moiré interferometry allow a three dimensional view of shape changes in the eye surface as laser treatment proceeds. Out-of-plane displacement reaches up to 1.5 mm with a single laser spot exposure. In-plane shrinkage reached a maximum of around 30%, which is similar to that reported by Sasoh et al (Ophthalmic Surg Lasers. 1998;29:410) for a Tm:YAG laser. The moiré technique is found to be suitable for quantifying the effects of CO2 laser scleral shrinkage and buckling. This can be further developed to provide a standardized method for experimental investigations of other laser sources for scleral shrinkage.

On-eye breakage and recovery of mini-scleral contact lens without compromise for the ocular surface.

PubMed

Macedo-de-Araújo, Rute J; van der Worp, Eef; González-Méijome, José M

2018-06-01

To report the on-eye breakage of a mini-scleral contact lens in a healthy cornea after being hit by a speeding object, without causing any severe corneal damage. A 24-year-old Caucasian male involved in a clinical study reported the in situ breakage of a mini-scleral contact lens during motorbike maintenance. The patient reported eye redness and irritation that significantly decreased after all the pieces of the lens were recovered from the eye. Ocular examinations within 48 h showed absence of corneal damage other than superficial punctate keratitis inferiorly and no fragments of the lens were found in the conjunctival sac. The patient was wearing a 15.2 mm mini-scleral lens in a high Dk material. The evolution of rigid materials towards higher Dk values has resulted in a decreased hardness and modulus values, so these materials are more elastic when subjected to mechanical stress, which could be a beneficial aspect in absorbing the energy of an impact before breaking in pieces. This case report shows that ScCL could have a protective effect to the corneal surface from the direct impact of a high-speed object. Mechanical material properties, wide supporting area and post-lens tear volume acted as protective factors helping to absorb and distribute the kinetic energy of the impacting object. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Simplified ab externo fixation technique to treat late dislocation of scleral-sutured polymethyl methacrylate intraocular lenses

PubMed Central

Lyu, J; Zhao, P-q

2016-01-01

Purpose We report a simplified ab externo scleral fixation technique to manage the late dislocation of scleral-sutured polymethyl methacrylate (PMMA) intraocular lenses (IOLs) in the absence of capsule support. Materials and methods The technique was performed on five eyes of five patients. Symmetrical scleral pocket tunnels without conjunctival peritomy were created. An anterior vitrectomy via a limbal approach with an anterior chamber infusion or a 3-port pars plana vitrectomy was performed to rescue the dislocated IOL. A long straight suture needle and 23-gauge vitreoretinal forceps were used to conveniently reposition the IOL and loop sutures through the IOL positioning eyelets without externalizing IOL haptics. The outside suture knots were buried under the roof of the scleral tunnels. Results The patients were followed for 5–14 months after surgery. All the operated eyes quickly recovered with negligible corneal endothelial cell loss and mild inflammation. Visual acuity improvement and IOL centration were achieved in all eyes with no major complications. Conclusion The simplified ab externo scleral fixation technique offers an effective and minimally invasive surgical alternative to salvage dislocated previously scleral-sutured PMMA IOLs. PMID:26795420

Simplified ab externo fixation technique to treat late dislocation of scleral-sutured polymethyl methacrylate intraocular lenses.

PubMed

Lyu, J; Zhao, P-Q

2016-05-01

PurposeWe report a simplified ab externo scleral fixation technique to manage the late dislocation of scleral-sutured polymethyl methacrylate (PMMA) intraocular lenses (IOLs) in the absence of capsule support.Materials and methodsThe technique was performed on five eyes of five patients. Symmetrical scleral pocket tunnels without conjunctival peritomy were created. An anterior vitrectomy via a limbal approach with an anterior chamber infusion or a 3-port pars plana vitrectomy was performed to rescue the dislocated IOL. A long straight suture needle and 23-gauge vitreoretinal forceps were used to conveniently reposition the IOL and loop sutures through the IOL positioning eyelets without externalizing IOL haptics. The outside suture knots were buried under the roof of the scleral tunnels.ResultsThe patients were followed for 5-14 months after surgery. All the operated eyes quickly recovered with negligible corneal endothelial cell loss and mild inflammation. Visual acuity improvement and IOL centration were achieved in all eyes with no major complications.ConclusionThe simplified ab externo scleral fixation technique offers an effective and minimally invasive surgical alternative to salvage dislocated previously scleral-sutured PMMA IOLs.

Noncontact optical coherence elastography of the posterior porcine sclera in situ as a function of IOP

NASA Astrophysics Data System (ADS)

Singh, Manmohan; Nair, Achuth; Aglyamov, Salavat R.; Wu, Chen; Han, Zhaolong; Lafon, Ericka; Larin, Kirill V.

2017-02-01

Recent work has shown that the biomechanical properties of tissues in the posterior eye have are critical for understanding the etiology and progression of ocular diseases. For instance, the primary risk for glaucoma is an elevated intraocular pressure (IOP). Weak tissues will deform under the large pressure, causing damage to vital tissues. In addition, scleral elasticity can influence the shape of the eye-globe, altering the axial length. In this work, we utilize a noncontact form of optical coherence elastography (OCE) to quantify the spatial distribution of biomechanical properties of the optic nerve, its surrounding tissues, and posterior sclera on the exterior of in situ porcine eyes in the whole eyeglobe configuration. The OCE measurements were taken at various IOPs to evaluate the biomechanical properties of the tissues as a function of IOP. The air-pulse induced dynamic response of the tissues was linked to Young's modulus by a simple kinematic equation by quantified the damped natural frequency (DNF). The results show that the posterior sclera is not as stiff as the optic nerve and its surrounding tissues ( 460 Hz and 894 Hz at 10 mmHg IOP, respectively). Moreover, the scleral stiffness was generally unaffected by IOP ( 460 Hz at 10 mmHg IOP as compared to 516 Hz at 20 mmHg), whereas the optic nerve and its surrounding tissues stiffened as IOP was increased ( 894 Hz at 10 mmHg to 1221 Hz at 20 mmHg).

Post-lens tear turbidity and visual quality after scleral lens wear.

PubMed

Carracedo, Gonzalo; Serramito-Blanco, Maria; Martin-Gil, Alba; Wang, Zicheng; Rodriguez-Pomar, Candela; Pintor, Jesús

2017-11-01

The aim was to evaluate the turbidity and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus after the beginning of lens wear and before lens removal at the end of eight hours. Twenty-six patients with keratoconus (aged 36.95 ± 8.95 years) participated voluntarily in the study. The sample was divided into two groups: patients with intrastromal corneal ring (ICRS group) and patients without ICRS (KC group). Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity (percentage area occupied and number of particles per mm 2 ) were evaluated with optical coherence tomography before and after wearing a scleral lens. A significant increase of turbidity was found in all groups assessed (p < 0.05). The number of particles per square millimetre was eight times higher after scleral lens wear than at the beginning of wearing the lens for all groups. VA decreases in all groups after scleral lens wear (p < 0.001). All patients showed a statistical diminishing of contrast sensitivity after scleral lens wear (p < 0.05). A significant correlation was found for both turbidity parameters with distance VA but no correlation between turbidity and post-lens tear layer thickness at the beginning was found (p > 0.05). A strong correlation in all groups between the post-lens tear layer at the beginning and differences of tear layer thickness between two measures was also found (p < 0.05). The VA decrease during the scleral lens wearing, filled with preserved saline solution, was due to the increasing post-lens tear layer turbidity. © 2017 Optometry Australia.

Comparison of clinical outcomes of iris fixation and scleral fixation as treatment for intraocular lens dislocation.

PubMed

Kim, Kyeong Hwan; Kim, Wan Soo

2015-09-01

To compare the efficacy and safety of iris fixation with scleral fixation in surgical repositioning of dislocated intraocular lenses (IOLs). Retrospective, consecutive, comparative interventional case series. setting: Referral hospital. Seventy-eight consecutive patients who underwent surgical repositioning of dislocated intraocular lenses using suturing to the sclera or iris. Forty-four eyes of 44 patients underwent scleral fixation and 35 eyes of 34 patients underwent iris fixation of dislocated intraocular lenses. Visual acuity, refractive stability, operation time, and perioperative complications, including recurrence of IOL dislocation. Corrected distance visual acuity (CDVA) improved significantly 1 month postoperatively in both groups (P < .01 each), and remained stable for 12 months. One week postoperatively, however, CDVA improved significantly in the scleral fixation (P = .040) but not in the iris fixation (P = .058) group. The amount of refractive error significantly diminished 1 day after surgery (P = .028 in the scleral fixation and P = .046 in the iris fixation group). For the astigmatic components, Jackson crossed cylinders equivalent to conventional cylinders of positive power at axes of 0 degrees (J0) and 45 degrees (J45), J45 differed significantly in the scleral fixation and iris fixation groups (P = .009), whereas J0 was similar (P > .05). Operation time was significantly shorter (P = .0007), while immediate postoperative inflammation was significantly more severe (P = .001), in the iris fixation than in the scleral fixation group. Recurrence rates were similar (P > .05), but the mean time to recurrence was significantly shorter in the iris fixation than in the scleral fixation group (P = .031). Iris fixation and scleral fixation techniques had similar efficacy in the repositioning of dislocated intraocular lenses. Although operation time was shorter for iris fixation, it had several disadvantages, including induced astigmatism

Scleral Lens Clearance Assessment with Biomicroscopy and Anterior Segment Optical Coherence Tomography.

PubMed

Yeung, Debby; Sorbara, Luigina

2018-01-01

It is important to be able to accurately estimate the central corneal clearance when fitting scleral contact lenses. Tools available have intrinsic biases due to the angle of viewing, and therefore an idea of the amount of error in estimation will benefit the fitter. To compare the accuracy of observers' ability to estimate scleral contact lens central corneal clearance (CCC) with biomicroscopy to measurements using slit-lamp imaging and anterior segment optical coherence tomography (AS-OCT). In a Web-based survey with images of four scleral lens fits obtained with a slit-lamp video imaging system, participants were asked to estimate the CCC. Responses were compared with known values of CCC of these images determined with an image-processing program (digital CCC) and using the AS-OCT (AS-OCT CCC). Bland-Altman plots and concordance correlation coefficients were used to assess the agreement of CCC measured by the various methods. Sixty-six participants were categorized for analysis based on the amount of experience with scleral lens fitting into novice, intermediate, or advanced fitters. Comparing the estimated CCC to the digital CCC, all three groups overestimated by an average of +27.3 ± 67.3 μm. The estimated CCC was highly correlated to the digital CCC (0.79, 0.92, and 0.94 for each group, respectively). Compared with the CCC measurements using AS-OCT, the three groups of participants overestimated by +103.3 μm and had high correlations (0.79, 0.93, and 0.94 for each group). Results from this study validate the ability of contact lens practitioners to observe and estimate the CCC in scleral lens fittings through the use of biomicroscopic viewing. Increasing experience with scleral lens fitting does not improve the correlation with measured CCC from digital or the AS-OCT. However, the intermediate and advanced groups display significantly less inter-observer variability compared with the novice group.

Experimental transconjunctival diode laser retinal photocoagulation through silicone scleral exoplants.

PubMed

Nanda, S K; Han, D P

1995-07-01

To study the feasibility of inducing a chorioretinal lesion under a previously placed scleral buckle by experimental transconjunctival diode laser photocoagulation. We performed transconjunctival diode laser photocoagulation in the peripheral retinas of seven pigmented rabbit eyes with a silicone exoplant (No. 42 band or No. 276 tire) and seven eyes without an exoplant. Each eye received burns with an intensity of grades 1 to 3 in different quadrants at varying power levels, with a 0.5-second duration and 650-micron spot size. Eyes were enucleated for histopathologic studies 1 day and 1 week after treatment. Although the irradiance emitted through the No. 42 band and the No. 276 tire was attenuated by 17% and 23%, respectively, the range of threshold powers needed to produce grades 1 to 3 burns was similar between eyes with and without a silicone exoplant. At 1 day, full-thickness coagulative necrosis was observed in all lesions, except that the ganglion cell layer and inner nuclear layer were preserved in two of four grade 1 burns and the ganglion cell layer was intact in one of six grade 2 burns. Inner scleral changes were noted acutely in three of five grade 3 lesions. At 1 week, burns of all intensity grades showed a full-thickness atrophic chorioretinal lesion with inner scleral changes. Experimental transconjunctival diode laser photocoagulation through hard silicone elements reproducibly created a chorioretinal lesion with histopathologic findings similar to those of lesions obtained without these elements. Although retinal photocoagulative effects were prominent, inner scleral abnormalities were also observed histologically.

Microbial keratitis secondary to unintended poor compliance with scleral gas-permeable contact lenses.

PubMed

Zimmerman, Aaron B; Marks, Amanda

2014-01-01

To report a case of neurotrophic keratitis in which scleral contact lenses improved vision from 20/100 to 20/20, however, due to poor lens care, an incident of microbial keratitis developed. A 64-year-old man with an ocular history of neurotrophic keratitis secondary to herpes simplex in each eye was successfully fit with scleral lenses. He subsequently developed microbial keratitis due to a number of risk factors. The lesion was culture negative, yet was very responsive to treatment with moxifloxacin. The lesion fully healed, and the patient did not suffer additional vision loss. This case demonstrates the ability of scleral lenses to correct visual impairments secondary to poor epithelial integrity and illustrates the importance of the practitioner providing detailed lens care instruction.

Perilimbal sclera mechanical properties: Impact on intraocular pressure in porcine eyes

PubMed Central

Man, Xiaofei; Arroyo, Elizabeth; Dunbar, Martha; Reed, David M.; Shah, Neil; Kagemann, Larry; Kim, Wonsuk; Moroi, Sayoko E.

2018-01-01

There is extensive knowledge on the relationship of posterior scleral biomechanics and intraocular pressure (IOP) load on glaucomatous optic neuropathy; however, the role for biomechanical influence of the perilimbal scleral tissue on the aqueous humor drainage pathway, including the distal venous outflow system, and IOP regulation is not fully understood. The purpose of this work is to study the outflow characteristics of perfused porcine eyes relative to the biomechanical properties of the perilimbal sclera, the posterior sclera and the cornea. Enucleated porcine eyes from eleven different animals were perfused with surrogate aqueous at two fixed flow rates while monitoring their IOP. After perfusion, mechanical stress-strain and relaxation tests were conducted on specimens of perilimbal sclera, posterior sclera, and cornea from the same perfused eyes. Statistical analysis of the data demonstrated a strong correlation between increased tangent modulus of the perilimbal sclera tissues and increased perfusion IOP (R2 = 0.74, p = 0.0006 at lower flow rate and R2 = 0.71, p = 0.0011 at higher flow rate). In contrast, there were no significant correlations between IOP and the tangent modulus of the other tissues (Posterior sclera: R2 = 0.17 at lower flow rate and R2 = 0.30 at higher flow rate; cornea: R2 = 0.02 at lower flow rate and R2<0.01 at higher flow rate) nor the viscoelastic properties of any tissue (R2 ≤ 0.08 in all cases). Additionally, the correlation occurred for IOP and not net outflow facility (R2 ≤ 0.12 in all cases). These results provide new evidence that IOP in perfused porcine eyes is strongly influenced by the tangent modulus, sometimes called the tissue stiffness, of the most anterior portion of the sclera, i.e. the limbus. PMID:29718942

Therapeutic use of mini-scleral lenses in a patient with Graves' ophthalmopathy.

PubMed

Harthan, Jennifer S

2014-01-01

Patients with Graves' ophthalmopathy can be very challenging to manage secondary to the complex nature of their disease presentation. Patients may present with a variety of ocular findings including: lid retraction, periorbital and lid swelling, chemosis, conjunctival hyperemia, proptosis, optic neuropathy, restrictive myopathy, exposure keratopathy and/or keratoconjunctivitis sicca. Mini-scleral and scleral lens designs have been important in the management of irregular and regular corneas, and in the therapy of ocular surface diseases. We present here the case of a 48-year-old Caucasian male who had been diagnosed with Graves' ophthalmopathy 13 years earlier. With significant ocular surface staining and over ten diopters of astigmatism, the patient had never been able to wear contact lenses comfortably. After being fit with the Mini-Scleral Design™ lenses, his vision improved to 20/25 OU, his ocular surface improved, and overall quality of vision increased. Copyright © 2012 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Correlation Between Biomechanical Responses of Posterior Sclera and IOP Elevations During Micro Intraocular Volume Change

PubMed Central

Morris, Hugh J.; Tang, Junhua; Cruz Perez, Benjamin; Pan, Xueliang; Hart, Richard T.; Weber, Paul A.; Liu, Jun

2013-01-01

Purpose. This study tested the hypothesis that intraocular pressure (IOP) elevations, induced by controlled increase of intraocular volume, are correlated with the biomechanical responses of the posterior sclera. Methods. Porcine globes were tested within 48 hours postmortem. The first group of globes (n = 11) was infused with 15 μL of phosphate-buffered saline at three different rates to investigate rate-dependent IOP elevations. The second group (n = 16) was first infused at the fast rate and then underwent inflation tests to investigate the relationship between IOP elevations (ΔIOP) and scleral strains. The strains in the superotemporal region of the posterior sclera were measured by ultrasound speckle tracking. Linear regression was used to examine the association between ΔIOP due to micro-volumetric infusion and the scleral strains at a specific inflation pressure. Results. The average ΔIOP was 14.9 ± 4.3 mm Hg for the infusion of 15 μL in 1 second. The ΔIOP was greater for the faster infusion rates but highly correlated across different rates (P < 0.001). A significant negative association was found between the ΔIOP and the tangential strains in both the circumferential (R2 = 0.54, P = 0.003) and meridian (R2 = 0.53, P = 0.002) directions in the posterior sclera. Conclusions. This study showed a substantial increase in IOP, with a large intersubject variance during micro-volumetric change. A stiffer response of the sclera was associated with larger IOP spikes, providing experimental evidence linking corneoscleral biomechanics to IOP fluctuation. In vivo measurement of corneoscleral biomechanics may help better predict the dynamic profile of IOP. PMID:24130185

Interactions between biomaterials and the sclera: Implications on myopia progression

NASA Astrophysics Data System (ADS)

Su, James

Myopia prevalence has steadily climbed worldwide in recent decades with the most dramatic impact in East Asian countries. Treatments such as eyeglasses, contact lenses, and laser surgery for the refractive error are widely available, but none cures the underlying cause. In progressive high myopia, invasive surgical procedures using a scleral buckle for mechanical support are performed since the patient is at risk of becoming blind. The treatment outcome is highly dependent on the surgeon's skills and the patient's myopia progression rate, with limited choices in buckling materials. This dissertation, in four main studies, represents efforts made to control high myopia progression through the exploration and development of biomaterials that influence scleral growth. First, mRNA expression levels of the chick scleral matrix metalloproteinases, tissue-inhibitor of matrix metalloproteinases, and transforming growth factor-beta 2 were assessed for temporal and defocus power effects. The first study elucidated the roles that these factors play in scleral growth regulation and suggested potential motifs that can be incorporated in future biomaterials design. Second, poly(vinyl-pyrrolidone) as injectable gels and poly(2-hydroxyethyl methacrylate) as solid strips were implanted in chicks to demonstrate the concept of posterior pole scleral reinforcements. This second study found that placing appropriate biomaterials at the posterior pole of the eye could directly influence scleral remodeling by interacting with the host cells. Both studies advanced the idea that scleral tissue remodeling could be potentially controlled by well-designed biomaterials. These findings led to the exploration of biomimetic hydrogels comprising enzymatically-degradable semi-interpenetrating polymer networks (edsIPNs) to determine their biocompatibility and effects on the chick posterior eye wall. This third study demonstrated the feasibility of stimulating scleral growth by applying biomimetic

Surgically Induced Scleral Necrosis in a Patient With Rheumatoid Arthritis After AGV Implantation.

PubMed

Kumar, Suresh; Ichhpujani, Parul; Thakur, Sahil

2018-03-01

Surgically induced scleral necrosis (SINS) is a rare entity that has till date not been reported in a patient of glaucoma undergoing Ahmed glaucoma valve (AGV) implantation. We present a case of primary open-angle glaucoma who underwent AGV implantation followed by development of scleral necrosis, involving both the scleral patch graft and host sclera. After failure of surgical and medical management, AGV had to be explanted. The patient was diagnosed with rheumatoid arthritis and had to be treated with steroids and azathioprine for the same. SINS is a potentially disastrous complication of ocular surgery that can occur in patients with systemic diseases like rheumatoid arthritis and requires aggressive management to salvage the eye. SINS can occur with AGV implantation. Treatment may require aggressive medical and surgical intervention. It is imperative to evaluate patients for systemic illness before planning an AGV implant.

Fitting an MSD (mini scleral design) rigid contact lens in advanced keratoconus with INTACS.

PubMed

Dalton, Kristine; Sorbara, Luigina

2011-12-01

Keratoconus is a bilateral degenerative disease characterized by a non-inflammatory, progressive central corneal ectasia (typically asymmetric) and decreased vision. In its early stages it may be managed with spectacles and soft contact lenses but more commonly it is managed with rigid contact lenses. In advanced stages, when contact lenses can no longer be fit, have become intolerable, or corneal damage is severe, a penetrating keratoplasty is commonly performed. Alternative surgical techniques, such as the use of intra-stromal corneal ring segments (INTACS) have been developed to try and improve the fit of rigid contact lenses in keratoconic patients and avoid penetrating keratoplasties. This case report follows through the fitting of rigid contact lenses in an advanced keratoconic cornea after an INTACS procedure and discusses clinical findings, treatment options, and the use of mini-scleral and scleral lens designs as they relate to the challenges encountered in managing such a patient. Mini-scleral and scleral lenses are relatively easy to fit, and can be of benefit to many patients, including advanced keratoconic patients, post-INTAC patients and post-penetrating keratoplasty patients. 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

cAMP Level Modulates Scleral Collagen Remodeling, a Critical Step in the Development of Myopia

PubMed Central

Liu, Shufeng; Fang, Fang; Lu, Runxia; Lu, Chanyi; Zheng, Min; An, Jianhong; Xu, Hongjia; Zhao, Fuxin; Chen, Jiang-fan; Qu, Jia; Zhou, Xiangtian

2013-01-01

The development of myopia is associated with decreased ocular scleral collagen synthesis in humans and animal models. Collagen synthesis is, in part, under the influence of cyclic adenosine monophosphate (cAMP). We investigated the associations between cAMP, myopia development in guinea pigs, and collagen synthesis by human scleral fibroblasts (HSFs). Form-deprived myopia (FDM) was induced by unilateral masking of guinea pig eyes. Scleral cAMP levels increased selectively in the FDM eyes and returned to normal levels after unmasking and recovery. Unilateral subconjunctival treatment with the adenylyl cyclase (AC) activator forskolin resulted in a myopic shift accompanied by reduced collagen mRNA levels, but it did not affect retinal electroretinograms. The AC inhibitor SQ22536 attenuated the progression of FDM. Moreover, forskolin inhibited collagen mRNA levels and collagen secretion by HSFs. The inhibition was reversed by SQ22536. These results demonstrate a critical role of cAMP in control of myopia development. Selective regulation of cAMP to control scleral collagen synthesis may be a novel therapeutic strategy for preventing and treating myopia. PMID:23951163

Pars plana vitrectomy for retinal detachment due to internal posterior ophthalmomyiasis after cataract extraction.

PubMed

Billi, B; Lesnoni, G; Audisio, P; Giuliano, M A; Rossi, T; Costi, E; Stirpe, M

1997-04-01

The authors report a case of posterior internal ophthalmomyiasis causing vitreous haemorrhage and retinal detachment after uncomplicated cataract extraction. The patient suffered an abrupt vitreous haemorrhage 9 days after ECCE and posterior chamber IOL implantation. After 2 months the haemorrhage did not clear up and a retinal detachment arose. The patient underwent encircling scleral buckle, pars plana vitrectomy and fluid-gas exchange. In course of intervention the surgeon removed from the vitreous chamber a 14-mm-long round worm subsequently identified as a dipterous larva of the Sarcophagidae family. The patient showed no sign of subretinal tracking or retinal breaks or holes. The sclerocorneal surgical wound seems the most likely site of entrance of the parasite, and this would then be the first reported case of myiasis with no RPE tracking.

An epibulbar chocolate cyst: a rare complication of silicone-based scleral buckle

PubMed Central

Venkatesh, Pradeep; Gogia, Varun; Gupta, Shikha; Nayak, Bhagabat

2015-01-01

A patient with a history of vitreoretinal surgery presented with nasal dystopia, diplopia and epibulbar bluish black mass simulating a chocolate cyst in the right eye. After a non-conclusive ocular examination, he underwent CT of the orbit along with volume rendition and three-dimensional reconstruction, which demonstrated intact globe with laterally displaced band-buckle assembly along with peri-scleral buckle element (SBE) soft tissue proliferation. Imaging-assisted exploration of the lesion was performed and retained scleral buckle element (SBE) was removed in toto; thus relieving the patient long-standing dystopia. PMID:26240109

Expanding MIRAgel scleral buckle simulating an orbital tumor in four cases.

PubMed

Shields, Carol L; Demirci, Hakan; Marr, Brian P; Mashayekhi, Arman; Materin, Miguel A; Shields, Jerry A

2005-01-01

To describe four patients with an enlarging orbital mass from a swollen MIRAgel scleral buckle that simulated an orbital neoplasm. In a retrospective, single-center case series at the Ocular Oncology Service at Wills Eye Hospital of Thomas Jefferson University, 4 eyes of 4 patients were referred for evaluation and treatment of a suspected orbital tumor. The initial presenting features were orbital mass (case 1), strabismus (case 2), and conjunctival mass with orbital extension (cases 3 and 4). Each patient vaguely recalled previous uncomplicated retinal detachment surgery 12 to 20 years earlier. Confirmation of the buckling implant material was made with the retina surgeon in 3 cases. A nontender, forniceal conjunctival mass, deep to the Tenon fascia and appearing as a translucent firm elevation was seen in all 4 cases. Axial CT (case 1) revealed a circumscribed anterior temporal orbital mass, believed to be a large inclusion cyst, 4 times thicker than the nasal scleral buckle. Ocular ultrasonography depicted an echolucent mass in the episcleral region (cases 3 and 4) that was 2 times thicker than the nasal scleral buckle (case 3). Excision was attempted in case 1, but only piecemeal removal was achieved, leading to extensive postoperative inflammation and decreased vision. The other 3 cases were followed conservatively without excision because they were each recognized to be a swollen MIRAgel implant and not an orbital tumor. MIRAgel scleral buckle material can greatly enlarge over a period of 10 years and simulate an orbital tumor or orbital cyst. Patients often do not recall details of the retinal surgery. Caution is advised regarding excision of this material because it is friable and can lead to extensive postoperative inflammation.

Reconstruction of delayed scleral flap melting with bovine pericardium after trabeculectomy with mitomycin C

PubMed Central

Coutinho, Inês; Silva, Diana; Mota, Mafalda; Lisboa, Maria; Trancoso Vaz, Fernando; Prieto, Isabel

2017-01-01

Aim: To present a challenging case of hypotony after trabeculectomy and its treatment. Case description: A 22-year-old woman with juvenile glaucoma underwent a conventional trabeculectomy with mitomycin C on the right eye (OD). In the immediate postoperative period, we observed a hyperfiltration bleb with hypotony refractory to conservative measures leading to hypotony maculopathy. A surgical revision with scleral flap resuture and conjunctival graft was performed with a satisfactory result and resolution of hypotony maculopathy. After two years, the patient complained of low visual acuity (VA) of the OD. During examination, we observed a fine and avascular bleb with Seidel and visualization of the underlying uveal tissue, an intraocular pressure (IOP) of 5 mmHg, and chorioretinal folds. A new revision of the trabeculectomy was performed. During the procedure, it was not possible to identify the scleral flap, so the fistula was closed with a patch of collagenous membrane derived from bovine pericardium (Tutopatch® graft). A good clinical evolution occurred. After 2 months, IOP was 15 mmHg without Seidel or changes in the fundus and VA was 20/20. After 8 months of follow-up, the IOP remains stable without further complaints. Conclusion: This case illustrates the difficulties faced in the management of a common complication of trabeculectomy and highlights some of the options available for its treatment. There are few reports of scleral melting after trabeculectomy. However, trauma and scleral necrosis associated with mitomycin are listed as the main causes. The use of a scleral patch derived from bovine pericardium allows effective suturing and closure of the aqueous leak. PMID:28695073

Influence of Scleral Buckling Surgery with Encircling Band on Subfoveal Choroidal Thickness in Long-Term Observations

PubMed Central

Laudańska-Olszewska, Iwona; Gozdek, Piotr; Maroszyński, Mariusz; Amon, Michael

2013-01-01

Purpose. The aim of this study is the presentation of subfoveal choroidal thickness with enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) several months after scleral buckling with encircling band surgery. Methods. 48 patients who underwent scleral buckling with encircling band surgery for unilateral rhegmatogenous retinal detachment were included in the retrospective observational study. The mean time from scleral buckling surgery to the final EDI-OCT examination was 22±6.7 months. We compare choroidal thickness between operated and fellow eyes. Results. In all patients, the macula was detached before the surgery. The subfoveal choroidal thickness in 48 treated eyes was 260.9±45.8 µm (range 155–383 µm) and in the fellow eyes was 217.5±36.7 µm (range 98–326 µm). The subfoveal choroidal thickness of eyes after scleral buckling surgery in long-term EDI-OCT examination was significantly thicker (P<0.001) than in fellow eyes. Conclusions. The subfoveal choroid in eyes undergoing encircling band surgery was significantly thicker than in fellow eyes. We suspect that this may be the result of reduced choroidal blood flow. It also seems that the width and size of the material used in scleral buckling surgery may affect a change in the choroid circulation and increase subfoveal choroidal thickness. PMID:23841077

Dose-dependent collagen cross-linking of rabbit scleral tissue by blue light and riboflavin treatment probed by dynamic shear rheology.

PubMed

Schuldt, Carsten; Karl, Anett; Körber, Nicole; Koch, Christian; Liu, Qing; Fritsch, Anatol W; Reichenbach, Andreas; Wiedemann, Peter; Käs, Josef A; Francke, Mike; Iseli, Hans Peter

2015-08-01

To determine the visco-elastic properties of isolated rabbit scleral tissue and dose-dependent biomechanical and morphological changes after collagen cross-linking by riboflavin/blue light treatment. Scleral patches from 87 adult albino rabbit eyes were examined by dynamic shear rheology. Scleral patches were treated by riboflavin and different intensities of blue light (450 nm), and the impact on the visco-elastic properties was determined by various rheological test regimes. The relative elastic modulus was calculated from non-treated and corresponding treated scleral patches, and treatments with different blue light intensities were compared. Shear rheology enables us to study the material properties of scleral tissue within physiological relevant parameters. Cross-linking treatment increased the viscous as well as the elastic modulus and changed the ratio of the elastic versus viscous proportion in scleral tissue. Constant riboflavin application combined with different blue light intensities from 12 mW/cm(2) up to 100 mW/cm(2) increased the relative elastic modulus of scleral tissue by factors up to 1.8. Further enhancement of the applied light intensity caused a decline of the relative elastic modulus. This might be due to destructive changes of the collagen bundle structure at larger light intensities, as observed by histological examination. Collagen cross-linking by riboflavin/blue light application increases the biomechanical stiffness of the sclera in a dose-dependent manner up to certain light intensities. Therefore, this treatment might be a suitable therapeutic approach to stabilize the biomechanical properties of scleral tissue in cases of pathological eye expansion. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

An epibulbar chocolate cyst: a rare complication of silicone-based scleral buckle.

PubMed

Venkatesh, Pradeep; Gogia, Varun; Gupta, Shikha; Nayak, Bhagabat

2015-08-03

A patient with a history of vitreoretinal surgery presented with nasal dystopia, diplopia and epibulbar bluish black mass simulating a chocolate cyst in the right eye. After a non-conclusive ocular examination, he underwent CT of the orbit along with volume rendition and three-dimensional reconstruction, which demonstrated intact globe with laterally displaced band-buckle assembly along with peri-scleral buckle element (SBE) soft tissue proliferation. Imaging-assisted exploration of the lesion was performed and retained scleral buckle element (SBE) was removed in toto; thus relieving the patient long-standing dystopia. 2015 BMJ Publishing Group Ltd.

Solvent-free biodegradable scleral plugs providing sustained release of vancomycin, amikacin, and dexamethasone--an in vivo study.

PubMed

Peng, Yi-Jie; Kau, Yi-Chuan; Wen, Chin-Wei; Liu, Kuo-Sheng; Liu, Shih-Jung

2010-08-01

Delivering effective drugs at sufficiently high concentrations to the area of infection is a standard treatment for infectious disease, such as endophthalmitis. This is currently done by empirical trans pars plana intravitreal injection of both antibiotics directed against gram-positive and gram-negative microorganisms and steroids. However, injections by needles repeatedly may increase the risks of intraocular infection and hemorrhage, as well as retinal detachment. This article explores the alternative of using biodegradable polymers as scleral plugs for a long-term drug release in vivo. To manufacture plugs, poly(lactide-glycolide) copolymers were first mixed with vancomycin, amikacin, and dexamethasone. The mixture was compressed and sintered at 55 degrees C to form scleral plugs 1.4 mm in diameter. Biodegradable scleral plugs released high concentrations of antibiotics (well above the minimum inhibitory concentrations, MIC) and steroids in vivo for the period of time needed to treat intraocular infection. In addition, no major complications such as infectious or sterile endophthalmitis, retinal detachment, ocular phthisis, or uvea protrusion at sclerotomy site were observed throughout the experiment. The sclerotomy wound healed after total degradation of the scleral implants without leakage or local necrosis. Antibiotic/steroid-impregnated biodegradable scleral plugs may have a potential role in the treatment of various intraocular infections. (c) 2010 Wiley Periodicals, Inc.

Wavefront-Guided Scleral Lens Correction in Keratoconus

PubMed Central

Marsack, Jason D.; Ravikumar, Ayeswarya; Nguyen, Chi; Ticak, Anita; Koenig, Darren E.; Elswick, James D.; Applegate, Raymond A.

2014-01-01

Purpose To examine the performance of state-of-the-art wavefront-guided scleral contact lenses (wfgSCLs) on a sample of keratoconic eyes, with emphasis on performance quantified with visual quality metrics; and to provide a detailed discussion of the process used to design, manufacture and evaluate wfgSCLs. Methods Fourteen eyes of 7 subjects with keratoconus were enrolled and a wfgSCL was designed for each eye. High-contrast visual acuity and visual quality metrics were used to assess the on-eye performance of the lenses. Results The wfgSCL provided statistically lower levels of both lower-order RMS (p < 0.001) and higher-order RMS (p < 0.02) than an intermediate spherical equivalent scleral contact lens. The wfgSCL provided lower levels of lower-order RMS than a normal group of well-corrected observers (p < < 0.001). However, the wfgSCL does not provide less higher-order RMS than the normal group (p = 0.41). Of the 14 eyes studied, 10 successfully reached the exit criteria, achieving residual higher-order root mean square wavefront error (HORMS) less than or within 1 SD of the levels experienced by normal, age-matched subjects. In addition, measures of visual image quality (logVSX, logNS and logLIB) for the 10 eyes were well distributed within the range of values seen in normal eyes. However, visual performance as measured by high contrast acuity did not reach normal, age-matched levels, which is in agreement with prior results associated with the acute application of wavefront correction to KC eyes. Conclusions Wavefront-guided scleral contact lenses are capable of optically compensating for the deleterious effects of higher-order aberration concomitant with the disease, and can provide visual image quality equivalent to that seen in normal eyes. Longer duration studies are needed to assess whether the visual system of the highly aberrated eye wearing a wfgSCL is capable of producing visual performance levels typical of the normal population. PMID:24830371

Change in over-refraction after scleral lens settling on average corneas.

PubMed

Bray, Chelsea; Britton, Stephanie; Yeung, Debby; Haines, Lacey; Sorbara, Luigina

2017-07-01

The purpose of this study was to determine the change in over-refraction, if any, after a scleral lens settled on the eye for 6-8 h. Sixteen patients of varying refractive errors and normal corneal curvatures (measured with Pentacam ™ Oculus) were fitted with trial Mini-Scleral Design (MSD) scleral lenses (15.8 mm diameter) in one eye. The sagittal depths of the scleral lenses were selected by adding 350 μm to the corneal sagittal heights measured at a chord length of 15 mm with the Visante ™ optical coherence tomographer (OCT) anterior segment scans and picking the closest available trial lens in the set. Initial measurements were taken 30 min after lens insertion and included an auto-refraction, subjective refraction, and best sphere refraction over the contact lens. Visual acuities and Visante ™ OCT anterior segment scans were also taken. These measurements were repeated after 6-8 h of lens wear. Over the trial wearing period, the average change in the spherical component of the over-refraction was +0.06 D (S.D. 0.17) (p = 0.16). The average change in cylinder was +0.04 D (S.D. 0.19) (p = 0.33). The average absolute change in axis was 1.06° (S.D. 12.11) (p = 0.74). The average change in best sphere was +0.13 ± 0.30 D (p = 0.12). There was no significant change in visual acuity with the best sphere over-refraction over the 6-8 h wearing period. There was a significant change in central corneal clearance over the wearing period of 83 μm (S.D. 22) (p < 0.0001). Despite a significant change in the central corneal clearance due to thinning of the fluid reservoir as the scleral lens settled (an average decrease of 83 μm after wearing the lenses for 6-8 h), there was not a statistically significant change in the subjective over-refraction (sphere, cylinder, and axis) or best sphere or visual acuity. This study has confirmed that there is no link between reduction in central corneal clearance and change in over-refraction for average

Large pterygium surgery: When coverage of the scleral bed justifies graft rotation.

PubMed

Gargallo-Benedicto, A; Hernández Pérez, D; Olate-Pérez, Á; Betancur-Delgado, E; Cerdà-Ibáñez, M; Duch-Samper, A

2016-10-01

To perform a 12 month follow-up study to assess the safety and effectiveness of resection and conjunctival autograft fixed with Tissucol® in selected cases of large pterygium. The orientation of the graft was adapted to the morphology of the scleral bed for a better coverage free of traction, with limbal position being lost. A prospective, non-comparative study of 10 cases of grade II or superior pterygium (7 primary, 3 recurrent) with at least 8mm of limbal extension. A wide scleral bed was obtained after pterygium and Tenon resection, with larger grafts being required to cover the defects. A superior conjunctival autograft was harvested and fixed to bare sclera using Tissucol. The orientation was adapted to the morphology of the scleral bed and limbal position was lost. Patients were periodically assessed for recurrence and complications for a period of 12 months. Minor complications occurred in 4 eyes. In one case a buttonhole was formed during dissection of the graft. Two presented with small limbal dehiscence, but epithelialisation was completed in the first week. In a third case, it was necessary to increase topical corticosteroids for pyogenic granuloma on the donor site, with secondary increased intraocular pressure (IOP). There were no recurrences after 12 months follow-up. A conjunctival graft of appropriate size adapted to the morphology of the scleral bed to ensure good coverage free of tension, provides good surgical results in selected cases of pterygium, regardless of the conservation the limbal orientation, with no recurrences after one year follow-up. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Correction of irregular and induced regular corneal astigmatism with toric IOL after posterior segment surgery: a case series.

PubMed

Kolozsvári, Bence L; Losonczy, Gergely; Pásztor, Dorottya; Fodor, Mariann

2017-01-13

Toric intraocular lens (IOL) implantation can be an effective method for correcting corneal astigmatism in patients with vitreoretinal diseases and cataract. Our purpose is to report the outcome of toric IOL implantation in two cases - a patient with scleral-buckle-induced regular corneal astigmatism and a patient with keratoconus following pars plana vitrectomy. As far as we are aware, there are no reported cases of toric IOL implantation in a vitrectomized eye with keratoconus nor of toric IOL implantation in patients with scleral-buckle-induced regular corneal astigmatism. Two patients with myopia and high corneal astigmatism underwent cataract operation with toric IOL implantation after posterior segment surgery. Myopia and high astigmatism (>2.5 diopter) were caused by previous scleral buckling in one case and by keratoconus in the other case. Pre- and postoperative examinations during the follow-up of included uncorrected and spectacle corrected distance visual acuity (UCDVA/CDVA), automated kerato-refractometry (Topcon), Pentacam HR, IOL Master (Zeiss) axial length measurements and fundus optical coherence tomography (Zeiss). One year postoperatively, the UCDVA and CDVA were 20/25 and 20/20 in both cases, respectively. The absolute residual refractive astigmatism was 1.0 and 0.75 Diopters, respectively. The IOL rotation was within 3° in both eyes, therefore IOL repositioning was not necessary. Complications were not observed in our cases. These cases demonstrate that toric IOL implantation is a predictable and safe method for the correction of high corneal astigmatism in complicated cases with different origins. Irregular corneal astigmatism in keratoconus or scleral-buckle-induced regular astigmatisms can be equally well corrected with the use of toric IOL during cataract surgery. Previous scleral buckling or pars plana vitrectomy seem to have no impact on the success of the toric IOL implantation, even in keratoconus. IOL rotational stability and

Oxygen diffusion and edema with modern scleral rigid gas permeable contact lenses.

PubMed

Compañ, Vicente; Oliveira, Cristina; Aguilella-Arzo, Marcel; Mollá, Sergio; Peixoto-de-Matos, Sofia C; González-Méijome, José M

2014-09-04

We defined the theoretical oxygen tension behind modern scleral contact lenses (CLs) made of different rigid gas permeable (RGP) materials, assuming different thickness of the tear layer behind the lens. A second goal was to show clinically the effect of the postlens tear film on corneal swelling. We simulated the partial pressure of oxygen across the cornea behind scleral CLs made of different lens materials (oxygen permeability Dk, 75-200 barrer) and different thickness (Tav, 100-300 μm). Postlens tear film thicknesses (Tpost-tear) ranging from 150 to 350 μm were considered. Eight healthy subjects were fitted randomly with a scleral lens with a thin and a thick postlens tear layer in two different sessions for a period of 3 hours under open-eye conditions. The CLs with less than 125 barrer of Dk and a thickness over 200 μm depleted the oxygen availability at the lens-cornea interface below 55 mm Hg for a postlens tear film of 150 μm. For a postlens tear film thickness of 350 μm, no combination of material or lens thickness will meet the criteria of 55 mm Hg. Our clinical measures of corneal edema showed that this was significantly higher (P < 0.001, Wilcoxon signed ranks test) with the thicker compared to the thinner Tpost-tear (mean ± SD, 1.66 ± 1.12 vs. 4.27 ± 1.19%). Scleral RGP CLs must be comprised of at least 125 barrer of oxygen permeability and up to 200 μm thick to avoid hypoxic effects even under open eye conditions. Postlens tear film layer should be below 150 μm to avoid clinically significant edema. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Surgical treatment of presbyopia: scleral, corneal, and lenticular.

PubMed

Baikoff, Georges

2004-08-01

Having solved most of the problems concerning myopia, hyperopia, and astigmatism, it is perfectly understandable that the surgical treatment of presbyopia should be next on the agenda. It is a new challenge where every possible aspect is explored. The past five years have been troubled by the debate over von Helmholtz theory on accommodation. Numerous investigations have been carried out on the primate and humans using various procedures. The more we learn about this mechanism, the nearer we will be to finding a solution to presbyopia. It appears essential to refer to recent works confirming von Helmholtz theory. Therefore, understanding presbyopia requires a great deal of optical ingenuity such as monovision, scleral modifications, which still remain controversial, or clear lens exchange or refilling. In 2003, with all the different techniques available, the surgeon has a wide choice to offer patients that are satisfactory from a practical, theoretical, and ethical point of view. However, these techniques must only be proposed once the patients have been carefully informed.

Treatment effects of microimplant-aided sliding mechanics on distal retraction of posterior teeth.

PubMed

Oh, Young-Hee; Park, Hyo-Sang; Kwon, Tae-Geon

2011-04-01

Our objective was to quantify the treatment effects of microimplant-aided mechanics on group distal retraction of the posterior teeth. The pretreatment and posttreatment cephalometric radiographs and dental casts of 23 patients (mean age, 22.1 ± 5.17 years), treated with distalization of the posterior teeth against microimplant anchorage and without extraction of the premolars or other teeth except the third molars, were used. The soft-tissue, skeletal, and dental measurements in the vertical and anteroposterior dimensions were analyzed. The changes in interpremolar and intermolar widths and rotations of the molars were analyzed with dental casts. The upper and lower lips were repositioned distally. The Frankfort horizontal to mandibular plane angle was decreased in the adult group. The maxillary posterior teeth were distalized by 1.4 to 2.0 mm with approximately 3.5° of distal tipping, and the mandibular posterior teeth were also distalized by 1.6 to 2.5 mm with approximately 6.6° to 8.3° of distal tipping. The maxillary posterior teeth showed intrusion by 1 mm. There were increases in arch widths at the premolars and molars. The overall success of microimplants was 89.7%; a well-experienced clinician had a higher success rate (98%) than did novices in this sample. The mean treatment time was 20 ± 4.9 months. With microimplant-aided sliding mechanics, clinicians can distalize all posterior teeth together with less distal tipping. The technique seems effective and efficient to treat patients who have mild arch length discrepancy without extractions. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

A non-surgical approach to the management of exposure keratitis due to facial palsy by using mini-scleral lenses.

PubMed

Zaki, Victor

2017-02-01

This is a retrospective study aimed to determine the efficacy of mini-scleral contact lens in protecting the cornea and improving vision in cases of facial palsy. Patients with facial palsy get exposure keratitis because the cornea is dry. They feel pain, discomfort and excessive watering. If left untreated, it leads to permanent damage to the cornea and loss of good functional vision. Mini-scleral lens keep the cornea covered by saline solution all wearing hours. Three patients (4 eyes) with acoustic neuroma, two unilateral and one bilateral, who underwent acoustic neuroma surgeries resulting in facial palsy, are presented.The gold implant and lateral tarsorrhaphy were not enough for corneal protection.Two patients (patients 1 and 2) suffered continuous pain and watering. They had to apply thick lubricant, Lacri-Lube ointment (Allergan, Inc., Dublin, Ireland), several times daily to the affected eye for 15 years. The vision of these patients in the affected eyes were counting fingers (CF) at one foot.Patient 3 with bilateral facial palsy had exposure keratitis in both eyes resulting in constant watering, pain and blurred vision. The 4 eyes were fitted with mini-scleral lenses. The lenses were 15.8 mm rigid gas permeable filled with preservative free saline solution that continuously covers the cornea all wearing hours. In patients 1 and 2 with unilateral facial palsy, vision improved through the mini-scleral lenses to 20/30 and all their symptoms disappeared.The keratitis in case 3 with bilateral facial palsy disappeared within one week of mini-scleral lens use.Follow up for 2 years showed that these patients maintained good vision with no side effects. Mini-scleral lenses protected the cornea, gave comfort and improved the vision and the quality of life of these three patients with facial palsy and should be considered for all patients with facial palsy.

[Superficial sponge anesthesia in cataract surgery (with scleral tunnel incision)].

PubMed

Pham, D T; Scherer, V; Wollensak, J

1996-12-01

The successful development of cataract operation and IOL implantation in the last decade has resulted in progressive shortening of the incision length as well as in developing safer and simpler anesthetic techniques. The purpose of the present study was to evaluate whether cataract surgery with scleral incision is possible using only topical sponge anesthesia with oxybuprocaine 0.4%. This method was compared with retrobulbar injection. 150 patients (3 groups each consisting 50 eyes) underwent phaco with scleral incision. 1st group: oxybuprocaine sponge anesthesia. 2nd group: oxybuprocaine sponge anesthesia combined with mild systemic analgesia (tramadol p.o.). 3rd group: retrobulbar injection (prilocaine/etidocaine mixture). All patients received medazolam premedication (Dormicum, 3/10 of 1 cc). Pain and discomfort during and after operation were investigated and statistically analyzed. Neither in group 1, 2 or 3 an additional subconjunctival injection was necessary. Pain or discomfort during operation was felt in 14 percent of the patients anesthetized with the oxybuprocaine sponge but only in 6 percent of the patients additionally premedicated with tramadol (2nd group). Also 6 percent of the patients after retrobulbar injection felt pain during operation. Postoperatively no significant differences between group 1 and 2 were obtained: 6 percent felt pain, 30 percent had a short term foreign body sensation. After retrobulbar injection (group 3) only 10 percent felt postoperative pain or discomfort. Topically applied oxybuprocaine provides sufficient anesthesia during cataract surgery with scleral incision. A combination with mild systemic analgesia (tramadol) helps to minimize pain and discomfort. Retrobulbur injection yielded only in the postoperative period significantly better analgesia. In the operating room full cooperation of the patient is required. Therefore we recommend not to use sponge anesthesia in cases when communication between surgeon and patient is

Transmuscular Migration of a Scleral Tunnel-Secured Encircling Silicone Band.

PubMed

Nishida, Yui; Fukumoto, Masanori; Kida, Teruyo; Suzuki, Hiroyuki; Ikeda, Tsunehiko

2016-01-01

The migration of an encircling silicone band through a rectus muscle is a rare postoperative complication associated with scleral buckling surgery for retinal detachment. In this present study, we describe what we believe to be the first reported case of a patient who experienced postoperative migration of an encircling silicone band through the rectus muscle, despite the band being surgically secured to the sclera in a scleral tunnel. A 58-year-old man presented with a rhegmatogenous retinal detachment in his left eye. Pars plana vitrectomy was performed with the placement of an encircling silicone band, and the patient's retina was successfully reattached. One year postoperatively, the encircling band became exposed on the nasal side of the conjunctiva next to the limbus without any symptoms. Two weeks later, the exposed encircling band was surgically removed without any complications. The findings of this study show that even when an encircling silicone band is surgically secured around the eye, periodic and careful postoperative follow-up examinations should be performed to ensure no migration of the band.

Upregulation of regulator of G-protein signaling 2 in the sclera of a form deprivation myopic animal model

PubMed Central

Zou, Leilei; Liu, Rui; Zhang, Xiaohui; Chu, Renyuan; Dai, Jinhui; Zhou, Hao

2014-01-01

Purpose Scleral remodeling is an important mechanism underlying the development of myopia. Atropine, an antagonist of G protein-coupled muscarinic receptors, is currently used as an off-label treatment for myopia. Regulator of G-protein signaling 2 (RGS2) functions as an intracellular selective inhibitor of muscarinic receptors. In this study we measured scleral RGS2 expression and scleral remodeling in an animal model of myopia in the presence or absence of atropine treatment. Methods Guinea pigs were assigned to four groups: normal (free of form deprivation), form deprivation myopia (FDM) for 4 weeks, FDM treated with saline, and FDM treated with atropine. Biometric measurements were then performed. RGS2 expression levels and scleral remodeling, including scleral thickness and collagen type I expression, were compared among the four groups. Results Compared with normal eyes and contralateral control eyes, the FDM eyes had the most prominent changes in refraction, axial length, and scleral remodeling, indicating myopia. There was no significant difference between control and normal eyes. Hematoxylin and eosin staining showed that the scleral thickness was significantly thinner in the posterior pole region of FDM eyes compared to normal eyes. Real-time PCR and western blot analysis showed a significant decrease in posterior scleral collagen type I mRNA and protein expression in the FDM eyes compared to the normal eyes. The FDM eyes also had increased levels of RGS2 mRNA and protein expression in the sclera. Atropine treatment attenuated the FDM-induced changes in refraction, axial length, and scleral remodeling. Interestingly, atropine treatment significantly increased collagen type I mRNA expression but decreased RGS2 mRNA and protein expression in the sclera of the FDM eyes. Conclusions We identified a significant RGS2 upregulation and collagen type I downregulation in the sclera of FDM eyes, which could be partially attenuated by atropine treatment. Our data

Mechanism of continence after repair of posterior urethral disruption: evidence of rhabdosphincter activity.

PubMed

Whitson, Jared M; McAninch, Jack W; Tanagho, Emil A; Metro, Michael J; Rahman, Nadeem U

2008-03-01

Controversy exists regarding continence mechanisms in patients who undergo posterior urethral reconstruction after pelvic fracture. Some evidence suggests that continence after posterior urethroplasty is maintained by the bladder neck or proximal urethral mechanism without a functioning distal mechanism. We studied distal urethral sphincter activity in patients who have undergone posterior urethroplasty for pelvic fracture. A total of 12 patients who had undergone surgical repair of urethral disruption involving the prostatomembranous region underwent videourodynamics with urethral pressure profiles at rest, and during stress and hold maneuvers. Bladder pressure and urethral pressure, including proximal and distal urethral sphincter activity and pressure, were assessed in each patient. All 12 patients had daytime continence of urine postoperatively with a followup after anastomotic urethroplasty of 12 to 242 months (mean 76). Average maximum urethral pressure was 71 cm H2O. Average maximum urethral closure pressure was 61 cm H2O. The average urethral pressure seen during a brief hold maneuver was 111 cm H2O. Average functional sphincteric length was 2.5 cm. Six of the 12 patients had clear evidence of distal urethral sphincter function, as demonstrated by the profile. Continence after anastomotic urethroplasty for posttraumatic urethral strictures is maintained primarily by the proximal bladder neck. However, there is a significant contribution of the rhabdosphincter in many patients.

The mechanical consequence of failure of ossified union in attempted posterior spinal fusion. A canine model.

PubMed

Stonecipher, T K; Vanderby, R; Sciammarella, C A; Lei, S S; Fisk, J R

1983-01-01

The mechanical behavior of pseudarthrosis in posterior spinal fusion was investigated. A canine model was developed in which an incompletely ossified posterior fusion mass was consistently produced. The spines were excised, and the motion segments were mechanically tested using a specially developed loading apparatus. Tests were performed to evaluate stiffness of the segments to loading with compression, torsion, and anterioposterior and lateral bending shear stiffness. Changes in other modes of loading were less consistent. The motion characteristics of the pseudarthrosis could not be predicted from the extent of the osseous defect noted on roentgenograms. These findings correlate clinically with the progression of curvature seen with pseudarthrosis in scoliosis surgery and the unpredictable results of pseudarthrosis in posterior fusion performed in treatment of degenerative disc disease.

[Treatment option for intralamellar corneo-scleral abscesses in the zone of tunnel incision after phacoemulsification].

PubMed

Kasparova, E A; Kasparov, A A

2012-01-01

The article provides data on clinical diagnosis (4 patients, 4 eyes) and early surgical treatment of corneal intralamellar abscesses (ICA) in the zone of corneo-scleral tunnel incision after phacoemulsification (PE). ICA developed via corneo-scleral incision was a relatively reliable biomicroscopic sign of the beginning chronic endophthalmitis. Despite of massive nonsurgical treatment (antibiotics, glucocorticoids, non-steroid anti-inflammatory agents etc.) inflammation was not arrested completely, it recurred within 2,5-6 months after PE. Reconstructive conjunctivo-sclerokeratoplasty resulted in arrest of inflammation and visual function recovery in 3 patients. In one patient this procedure was not possible to perform because of total loss of visual functions due to chronic endophthalmitis.

Outcomes and complications of hydrogel scleral explant removal.

PubMed

Chen, Ching J; Kosek, Kevin; Benvenutti, Erica

2012-01-01

To report symptoms of extrusion of hydrogel explants after retinal detachment (RD) repair and the outcomes and complications following removal. All 23 patients had previous RD repair by episcleral buckle with hydrogel explant. Signs and symptoms of scleral buckle (SB) extrusion were analyzed. Main outcomes measured were redetachment of the retina, persistent diplopia, and decreased postoperative visual acuity (VA). Mean time between RD repair and removal of extruded SB was 16.2 years (range: 11 to 21 years). Fifteen patients (65%) received encircling SB and 8 had segmental SB. SB was combined with vitrectomy in 12 patients and 3 received silicone oil. Common complaints included limited ocular motility, presence of a palpable mass under the eyelid, pain and discomfort, diplopia, visible SB under eroded conjunctiva, complete immobility, and signs of infection. Two eyes were phthisical. No scleral perforations occurred during removal of explants. After SB removal, RD recurred in 2 patients and diplopia persisted in 4. VA was not affected by SB removal. Deterioration may occur after implantation for 10 years or longer. This is due to microstructural change of the hydrogel material. The most common problems are motility disturbance and presence of a tumor-like, palpable mass under the eyelid. Removal of the implant can alleviate some ocular problems. However, RD can recur and diplopia may persist after removal of the SB. Vision usually is not affected. Copyright 2012, SLACK Incorporated.

78 FR 5327 - Medical Devices; Ophthalmic Devices; Classification of the Scleral Plug

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

... Agency) is proposing to classify the scleral plug into class II (special controls), and proposing to... controls needed to provide reasonable assurance of their safety and effectiveness. The three categories of devices are class I (general controls), class II (special controls), and class III (premarket approval...

Efficacy of long scleral tunnel technique in preventing Ahmed glaucoma valve tube exposure through conjunctiva.

PubMed

Kugu, Suleyman; Erdogan, Gurkan; Sevim, M Sahin; Ozerturk, Yusuf

2015-01-01

To evaluate the efficacy of long scleral tunnel technique used in Ahmed glaucoma valve (AGV) implantation in preventing tube exposure through conjunctiva. Patients of adult age, who were unresponsive to maximum medical treatment and underwent AGV implantation, were divided into two groups and investigated retrospectively. Group 1 consisted of 40 eyes of 38 patients that underwent surgery by long scleral tunnel technique and Group 2 consisted of 38 eyes of 35 patients that underwent implantation by processed pericardium patch graft method. The mean age was 54.8 ± 14.6 years (range 26-68 years) and the mean follow-up duration was 46.7 ± 19.4 months (range 18-76 months) for the patients in Group 1, whereas the mean age was 58.6 ± 16.7 years (range 32-74 years) and mean follow-up period was 43.6 ± 15.7 months (range 20-72 months) for the patients in Group 2 (p > 0.05). In the course of follow-up, tube exposure was detected in one (2.5%) eye in Group 1 and in three (7.9%) eyes in Group 2 (p = 0.042). Long scleral tunnel technique is beneficial in preventing conjunctival tube exposure in AGV implantation surgery.

Trans-scleral selective laser trabeculoplasty (SLT) without a gonioscopy lens (Conference Presentation)

NASA Astrophysics Data System (ADS)

Belkin, Michael; Geffen, Noa; Goldenfeld, Modi; Ofir, Shay; Belkin, Avner; Assia, Ehud

2016-03-01

Developing a one-second automatic glaucoma treatment using trans-scleral laser trabeculoplasty (LTP) without a gonioscopy lens Purpose: Developing an LTP device for delivering multiple simultaneous trans-scleral applications of low energy laser irradiation to the trabecular meshwork (TM) for reducing Intraocular Pressure (IOP). Methods: Concept proof: A randomized, masked, controlled one was performed on open angle glaucoma patients. The control group underwent conventional SLT (100 laser spots through a gonioscope for 360 degrees directly on the TM). The trial group underwent irradiation by the same laser at the same irradiation parameters on the sclera overlying the TM. Topical glaucoma therapy was not changed during the 12 months trial. Feasibility trial: Using optimized laser parameters, 60 discrete applications were administered on similar locations of patients' sclera. Results: Concept proof: Trans-scleral applications: (N=15), IOP decrease from 20.21 mmHg before treatment to 16.00 (27.1%) at one year. The corresponding numbers for the control group (n=15), were 21.14 mmHg and 14.30 (23.4%). There was no statistical difference between the two groups in IOP reduction. The complications rate was significantly higher in the control group. Trial 2: IOP was reduced from an of 25.3 mmHg to 19.3 (23.7%) in the 11 patients. Conclusions: Laser coherency, lost in tissue transmission, is not required for the therapeutic effect. The new method will possibly enable treatment of angle closure glaucoma as well as simultaneous applications of all laser spots to the sclera. When used conjointly with target acquisition, will make feasible an automatic glaucoma treatment in less than one second.

A Novel Mgp-Cre Knock-In Mouse Reveals an Anticalcification/Antistiffness Candidate Gene in the Trabecular Meshwork and Peripapillary Scleral Region.

PubMed

Borrás, Teresa; Smith, Matthew H; Buie, LaKisha K

2015-04-01

Soft tissue calcification is a pathological condition. Matrix Gla (MGP) is a potent mineralization inhibitor secreted by cartilage chondrocytes and arteries' vascular smooth muscle cells. Mgp knock-out mice die at 6 weeks due to massive arterial calcification. Arterial calcification results in arterial stiffness and higher systolic blood pressure. Intriguingly, MGP was highly abundant in trabecular meshwork (TM). Because tissue stiffness is relevant to glaucoma, we investigated which additional eye tissues use Mgp's function using knock-in mice. An Mgp-Cre-recombinase coding sequence (Cre) knock-in mouse, containing Mgp DNA plus an internal ribosomal entry site (IRES)-Cre-cassette was generated by homologous recombination. Founders were crossed with Cre-mediated reporter mouse R26R-lacZ. Their offspring expresses lacZ where Mgp is transcribed. Eyes from MgpCre/+;R26RlacZ/+ (Mgp-lacZ knock-in) and controls, 1 to 8 months were assayed for β-gal enzyme histochemistry. As expected, Mgp-lacZ knock-in's TM was intensely blue. In addition, this mouse revealed high specific expression in the sclera, particularly in the peripapillary scleral region (ppSC). Ciliary muscle and sclera above the TM were also positive. Scleral staining was located immediately underneath the choroid (chondrocyte layer), began midsclera and was remarkably high in the ppSC. Cornea, iris, lens, ciliary body, and retina were negative. All mice exhibited similar staining patterns. All controls were negative. Matrix Gla's restricted expression to glaucoma-associated tissues from anterior and posterior segments suggests its involvement in the development of the disease. Matrix Gla's anticalcification/antistiffness properties in the vascular tissue, together with its high TM and ppCS expression, place this gene as a strong candidate for TM's softness and sclera's stiffness regulation in glaucoma.

Effect of laser UV radiation on the eye scleral tissue in patients with open-angle glaucoma

NASA Astrophysics Data System (ADS)

Razhev, A. M.; Iskakov, I. A.; Churkin, D. S.; Orishich, A. M.; Maslov, N. A.; Tsibul'skaya, E. O.; Lomzov, A. A.; Ermakova, O. V.; Trunov, A. N.; Chernykh, V. V.

2018-05-01

We report the results of an experimental study of the effect of short-pulse laser UV radiation on the eye scleral tissue. As samples, we used isolated flaps of the eye scleral tissue from the patients with open-angle glaucoma of the second and third stages. The impact was implemented using the radiation of an excimer XeCl laser with a wavelength of 308 nm and a laser with a wavelength tunable within from 210 to 355 nm. Depending on the problem to be solved, the energy density on the surface of the irradiated tissue varied from a fraction of mJ cm-2 to 15 J cm-2. For the first time we studied the optical properties of the intraocular fluid in the UV and blue spectral range. The study of the ablation process under the action of radiation with a wavelength of 308 nm showed that the rate of material evaporation can vary within 24%–30% at an energy density above 7 J cm-2, depending on the glaucoma stage and the individual features of a patient. The excitation–emission matrices of laser-induced fluorescence (LIF) of the eye scleral tissue were studied experimentally using a laser with a wavelength tuned in the range 210–355 nm. We found the differences in the LIF spectra caused by the excitation wavelength and the openangle glaucoma stage.

Femtosecond laser subsurface scleral treatment in cadaver human sclera and evaluation using two-photon and confocal microscopy

NASA Astrophysics Data System (ADS)

Sun, Hui; Fan, Zhongwei; Yan, Ying; Lian, Fuqiang; Kurtz, Ron; Juhasz, Tibor

2016-03-01

Glaucoma is the second-leading cause of blindness worldwide and is often associated with elevated intraocular pressure (IOP). Partial-thickness drainage channels can be created with femtosecond laser in the translucent sclera for the potential treatment of glaucoma. We demonstrate the creation of partial-thickness subsurface drainage channels with the femtosecond laser in the cadaver human eyeballs and describe the application of two-photon microscopy and confocal microscopy for noninvasive imaging of the femtosecond laser created partial-thickness scleral channels in cadaver human eyes. A femtosecond laser operating at a wavelength of 1700 nm was scanned along a rectangular raster pattern to create the partial thickness subsurface drainage channels in the sclera of cadaver human eyes. Analysis of the dimensions and location of these channels is important in understanding their effects. We describe the application of two-photon microscopy and confocal microscopy for noninvasive imaging of the femtosecond laser created partial-thickness scleral channels in cadaver human eyes. High-resolution images, hundreds of microns deep in the sclera, were obtained to allow determination of the shape and dimension of such partial thickness subsurface scleral channels. Our studies suggest that the confocal and two-photon microscopy can be used to investigate femtosecond-laser created partial-thickness drainage channels in the sclera of cadaver human eyes.

Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma

PubMed Central

Pitha, Ian F.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary Ellen; Oglesby, Ericka N.; Berlinicke, Cynthia A.; Mitchell, Katherine L.; Kim, Jessica; Jefferys, Joan J.

2015-01-01

Purpose To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice. Methods We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Results Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP. Conclusions The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes

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.

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.

Assessment of eye bank-prepared posterior lamellar corneal tissue for endothelial keratoplasty.

PubMed

Rose, Linda; Briceño, César A; Stark, Walter J; Gloria, Dante G; Jun, Albert S

2008-02-01

To evaluate eye bank-prepared tissue for Descemet's stripping automated endothelial keratoplasty (DSAEK). Experimental study and retrospective case series. Seventeen human donor corneas and 4 recipient patients undergoing DSAEK surgery. Corneal-scleral discs were obtained. Specular microscopy and pachymetry were performed. A designated Tissue Banks International technician used a microkeratome to prepare a flap. Posterior bed thickness was measured. The sectioned tissue was stored, and at 24 and 48 hours, pachymetry was repeated. At 48 hours, specular microscopy was repeated, and endothelial cell viability was assessed with trypan blue. Descemet's stripping automated endothelial keratoplasty was performed in 4 patients using eye bank-prepared posterior lamellar tissue. Corneal tissue was assessed with the following parameters: corneal thickness measured with ultrasonic pachymetry, cell density counts measured with a keratoanalyzer, and cell viability as observed with trypan blue exclusion. Patient outcomes were measured by changes in visual acuity (VA) and the presence of a clear graft. Donor corneal pachymetry before sectioning averaged 599+/-52 microm. Immediately after sectioning with a microkeratome set at a depth of 300 microm, mean posterior bed thickness was 328+/-95 microm. Thus, the mean cutting depth achieved by the microkeratome when set at 300 micrometers averaged 271+/-83 microm. After storage for 24 hours, the posterior beds measured 352 microm, an average swelling of 24 (7%) microm (P = 0.14). After 48 hours, the posterior beds measured 382 microm, an average swelling of 54 (16%) microm (P = 0.02). Cell counts 48 hours after sectioning decreased by an average of 11% (P = 0.10). Endothelial cell staining confirmed improvement in postsectioning morphology and survival with increased technician experience. All 4 patients receiving eye bank-prepared DSAEK tissue showed uncomplicated postoperative results, with improvement in VA. The microkeratome cutting

The effect of scleral search coil lens wear on the eye.

PubMed

Murphy, P J; Duncan, A L; Glennie, A J; Knox, P C

2001-03-01

Scleral search coils are used to measure eye movements. A recent abstract suggests that the coil can affect the eye by decreasing visual acuity, increasing intraocular pressure, and damaging the corneal and conjunctival surface. Such findings, if repeated in all subjects, would cast doubt on the credibility of the search coil as a reliable investigative technique. The aim of this study was to reassess the effect of the scleral search coil on visual function. Six volunteer subjects were selected to undergo coil wear and baseline measurements were taken of logMAR visual acuity, non-contact tonometry, keratometry, and slit lamp examination. Four drops of 0.4% benoxinate hydrochloride were instilled before insertion of the lens by an experienced clinician. The lens then remained on the eye for 30 minutes. Measurements of the four ocular health parameters were repeated after 15 and 30 minutes of lens wear. The lens was then removed and the health of the eye reassessed. No obvious pattern of change was found in logMAR visual acuity, keratometry, or intraocular pressure. The lens did produce changes to the conjunctival and corneal surfaces, but this was not considered clinically significant. Search coils do not appear to cause any significant effects on visual function. However, thorough prescreening of subjects and post-wear checks should be carried out on all coil wearers to ensure no adverse effects have been caused.

Biomechanical Changes in the Sclera of Monkey Eyes Exposed to Chronic IOP Elevations

PubMed Central

Girard, Michaël J. A.; Suh, J.-K. Francis; Bottlang, Michael; Burgoyne, Claude F.

2011-01-01

Purpose. To characterize scleral biomechanics in both eyes of eight monkeys in which chronic intraocular pressure (IOP) elevation was induced in one eye. Methods. Each posterior sclera was mounted on a pressurization apparatus, IOP was elevated from 5 to 45 mm Hg while the 3D displacements of the scleral surface were measured by speckle interferometry. Finite element (FE) models of each scleral shell were constructed that incorporated stretch-induced stiffening and multidirectionality of the collagen fibers. FE model predictions were then iteratively matched to experimental displacements to extract unique sets of scleral biomechanical properties. Results. For all eyes, the posterior sclera exhibited inhomogeneous, anisotropic, nonlinear biomechanical behavior. Biomechanical changes caused by chronic IOP elevation were complex and specific to each subject. Specifically: (1) Glaucomatous eyes in which the contralateral normal eyes displayed large modulus or thickness were less prone to biomechanical changes; (2) glaucomatous scleral modulus associated with an IOP of 10 mm Hg decreased (when compared with that of the contralateral normal) after minimal chronic IOP elevation; (3) glaucomatous scleral modulus associated with IOPs of 30 and 45 mm Hg increased (when compared with that of the contralateral normal) after moderate IOP elevation; and (4) FE-based estimates of collagen fiber orientation demonstrated no change in the glaucomatous eyes. Conclusions. Significant stiffening of the sclera follows exposure to moderate IOP elevations in most eyes. Scleral hypercompliance may precede stiffening or be a unique response to minimal chronic IOP elevation in some eyes. These biomechanical changes are likely to be the result of scleral extracellular matrix remodeling. PMID:21519033

Estimation of axial curvature of anterior sclera: correlation between axial length and anterior scleral curvature as affected by angle kappa.

PubMed

Lee, Sang-Mok; Choi, Hyuk Jin; Choi, Heejin; Kim, Mee Kum; Wee, Won Ryang

2016-10-07

BACKGROUND: Though the development and fitting of scleral contact lenses are expanding steadily, there is no simple method to provide scleral metrics for scleral contact lens fitting yet. The aim of this study was to establish formulae for estimation of the axial radius of curvature (ARC) of the anterior sclera using ocular biometric parameters that can be easily obtained with conventional devices. A semi-automated stitching method and a computational analysis tool for calculating ARC were developed by using the ImageJ and MATLAB software. The ARC of all the ocular surface points were analyzed from the composite horizontal cross-sectional images of the right eyes of 24 volunteers; these measurements were obtained using anterior segment optical coherence tomography for a previous study (AS-OCT; Visante). Ocular biometric parameters were obtained from the same volunteers with slit-scanning topography and partial coherence interferometry. Correlation analysis was performed between the ARC at 8 mm to the axis line (ARC[8]) and other ocular parameters (including age). With ARC obtained on several nasal and temporal points (7.0, 7.5, 8.0, 8.5, and 9.0 mm from the axis line), univariate and multivariate linear regression analyses were performed to develop a model for estimating ARC with the help of ocular biometric parameters. Axial length, spherical equivalent, and angle kappa showed correlations with temporal ARC[8] (tARC[8]; Pearson's r = 0.653, -0.579, and -0.341; P = 0.001, 0.015, and 0.015, respectively). White-to-white corneal diameter (WTW) and anterior chamber depth (ACD) showed correlation with nasal ARC[8] (nARC[8]; Pearson's r = -0.492 and -0.461; P = 0.015 and 0.023, respectively). The formulae for estimating scleral curvatures (tARC, nARC, and average ARC) were developed as a function of axial length, ACD, WTW, and distance from the axis line, with good determinant power (72 - 80 %; SPSS ver. 22.0). Angle kappa showed strong

Scleral fixation of foldable acrylic intraocular lenses in aphakic post-vitrectomy eyes

PubMed Central

Mutoh, Tetsuya; Matsumoto, Yukihiro; Chikuda, Makoto

2011-01-01

Purpose To evaluate the outcome for scleral fixation of a foldable acrylic intraocular lens (IOL) in aphakic post-pars plana vitrectomy eyes for vitreoretinal disease. Methods The medical records of 15 patients were reviewed. We evaluated such factors as the underlying vitreoretinal disease, preoperative expected refraction and postoperative actual refraction, best corrected visual acuity (BCVA), corneal endothelial cell density, and intraoperative and postoperative complications. Results The most common cause of underlying vitreoretinal disease was retinal detachment, which was found in 8 cases. The mean refractive error was −0.10 diopters (D). The mean minimum angle of resolution (logMAR) values of BCVA were 0.27 preoperatively and 0.14 postoperatively. The mean corneal endothelial cell density was 2400 cells/mm2 preoperatively and 2187 cells/mm2 postoperatively. No significant differences were observed in either the logMAR values of BCVA or the corneal endothelial cell density before and after surgery. No intraoperative complications occurred in any of the patients. Postoperative complications occurred in a total of 7 eyes, and the most severe complications comprised 4 cases of transient ocular hypertension. Conclusion The results for the scleral fixation of foldable acrylic IOLs were good in aphakic post-vitrectomy eyes. PMID:21311652

GoPro HERO 4 Black recording of scleral buckle placement during retinal detachment repair.

PubMed

Ho, Vincent Y; Shah, Vaishali G; Yates, David M; Shah, Gaurav K

2017-08-01

GoPro and Google Glass technology have previously been used to record procedures in ophthalmology and other medical fields. In this manuscript, GoPro's latest HERO 4 Black edition camera (GoPro Inc, San Mateo, Calif.) will be used to record the placement of a scleral buckle during retinal detachment surgery. GoPro HERO 4 Black edition camera, which records 4K-quality video with a resolution of 3840 (pixels) x 2160 (lines), was mounted on a head strap to record placement of a scleral buckle for a retinal detachment. Excellent video quality was achieved with the 4K SuperView setting. Bluetooth connection with an Apple iPad (Apple Inc, Cupertino, Calif.) provided live streaming and use of the GoPro App. Zoom, horizontal/vertical alignment, exposure, and contrast adjustments were made with postproduction editing on GoPro Studio software. Video recording with the GoPro HERO 4 Black edition camera is an excellent way to document extraocular procedures to improve medical education, self-training, or medicolegal documentation. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Scleral Contact Lenses in an Academic Oculoplastics Clinic: Epidemiology and Emerging Considerations.

PubMed

Chahal, Harinder S; Estrada, Marcela; Sindt, Christine W; Boehme, Jacob A; Greiner, Mark A; Nerad, Jeffrey A; Carter, Keith D; Allen, Richard C; Shriver, Erin M

To describe the role and efficacy of scleral contact lenses (SCLs) in the treatment of progressive keratopathy in patients who have undergone periocular surgical procedures, to investigate the financial impact of these surgical interventions, and to demonstrate the role of oculoplastic surgery in improving scleral contact lens fit. A retrospective medical record review was performed to identify patients who both received SCLs and were examined by the oculoplastics service at the University of Iowa between January 1990 and December 2015. Inclusion criteria also required a minimum of 12 months of patient follow up after being fit with a SCL. The indication for SCL use, as well as clinical outcomes and cumulative relative value units (RVUs) of prior oculoplastic treatments and SCL therapy were recorded for each patient. Six hundred and fifty-nine patients were fitted with SCLs at the authors' institution during the 25-year study period, 43 of whom were examined by the oculoplastics service for reasons related to their SCL. Patients who were fitted for SCLs before (27 patients) or after (16 patients) evaluation in the oculoplastics clinic presented with a variety of corneal and periocular pathology. Corneal indications for SCLs in patients seen secondarily in the oculoplastics clinic included decreased corneal sensation (from CN V palsy or neurotrophic keratopathy), decreased corneal healing from limbal stem cell deficiency, exposure keratopathy, and keratoconjunctivitis sicca secondary to Sjogren's syndrome or orbital radiation. Indications for oculoplastic clinic evaluation in current scleral lens patients included lagophthalmos, trichiasis, epiphora, cicatricial changes in the eyelids or fornices, and eyelid or eyebrow malposition affecting SCL centration. In all 27 patients, surgical intervention resulted in improved SCL centration. Sixteen patients (5 with CN VII palsy, 4 with CN V and CN VII palsy, 4 with neurotrophic keratitis, and 3 with cicatricial entropion

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

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.

Pars plana Ahmed valve and vitrectomy in patients with glaucoma associated with posterior segment disease.

PubMed

Wallsh, Josh O; Gallemore, Ron P; Taban, Mehran; Hu, Charles; Sharareh, Behnam

2013-01-01

To assess the safety and efficacy of a modified technique for pars plana placement of the Ahmed valve in combination with pars plana vitrectomy in the treatment of glaucoma associated with posterior segment disease. Thirty-nine eyes with glaucoma associated with posterior segment disease underwent pars plana vitrectomy combined with Ahmed valve placement. All valves were placed in the pars plana using a modified technique, without the pars plana clip, and using a scleral patch graft. The 24 eyes diagnosed with neovascular glaucoma had an improvement in intraocular pressure from 37.6 mmHg to 13.8 mmHg and best-corrected visual acuity from 2.13 logarithm of minimum angle of resolution to 1.40 logarithm of minimum angle of resolution. Fifteen eyes diagnosed with steroid-induced glaucoma had an improvement in intraocular pressure from 27.9 mmHg to 14.1 mmHg and best-corrected visual acuity from 1.38 logarithm of minimum angle of resolution to 1.13 logarithm of minimum angle of resolution. Complications included four cases of cystic bleb formation and one case of choroidal detachment and explantation for hypotony. Ahmed valve placement through the pars plana during vitrectomy is an effective option for managing complex cases of glaucoma without the use of the pars plana clip.

The effect of scleral search coil lens wear on the eye

PubMed Central

Murphy, P.; Duncan, A.; Glennie, A.; Knox, P.

2001-01-01

BACKGROUND/AIM—Scleral search coils are used to measure eye movements. A recent abstract suggests that the coil can affect the eye by decreasing visual acuity, increasing intraocular pressure, and damaging the corneal and conjunctival surface. Such findings, if repeated in all subjects, would cast doubt on the credibility of the search coil as a reliable investigative technique. The aim of this study was to reassess the effect of the scleral search coil on visual function.
METHODS—Six volunteer subjects were selected to undergo coil wear and baseline measurements were taken of logMAR visual acuity, non-contact tonometry, keratometry, and slit lamp examination. Four drops of 0.4% benoxinate hydrochloride were instilled before insertion of the lens by an experienced clinician. The lens then remained on the eye for 30 minutes. Measurements of the four ocular health parameters were repeated after 15 and 30 minutes of lens wear. The lens was then removed and the health of the eye reassessed.
RESULTS—No obvious pattern of change was found in logMAR visual acuity, keratometry, or intraocular pressure. The lens did produce changes to the conjunctival and corneal surfaces, but this was not considered clinically significant.
CONCLUSION—Search coils do not appear to cause any significant effects on visual function. However, thorough prescreening of subjects and post-wear checks should be carried out on all coil wearers to ensure no adverse effects have been caused.

 PMID:11222341

Scleral Buckling Using a Non-contact Wide-Angle Viewing System with a 25-Gauge Chandelier Endoilluminator.

PubMed

Jo, Jaehyuck; Moon, Byung Gil; Lee, Joo Yong

2017-12-01

To report the outcome of scleral buckling using a non-contact wide-angle viewing system with a 25-gauge chandelier endoilluminator. Retrospective analyses of medical records were performed for 17 eyes of 16 patients with primary rhegmatogenous retinal detachment (RRD) without proliferative vitreoretinopathy who had undergone conventional scleral buckling with cryoretinopexy using the combination of a non-contact wide-angle viewing system and chandelier endoillumination. The patients were eight males and five females with a mean age of 26.8 ± 10.2 (range, 11 to 47) years. The mean follow-up period was 7.3 ± 3.1 months. Baseline best-corrected visual acuity was 0.23 ± 0.28 logarithm of the minimum angle of resolution units. Best-corrected visual acuity at the final visit showed improvement (0.20 ± 0.25 logarithm of the minimum angle of resolution units), but the improvement was not statistically significant (p = 0.722). As a surgery-related complication, there was vitreous loss at the end of surgery in one eye. As a postoperative complication, increased intraocular pressure (four cases) and herpes simplex epithelial keratitis (one case) were controlled postoperatively with eye drops. One case of persistent RRD after primary surgery needed additional vitrectomy, and the retina was postoperatively attached. Scleral buckling with chandelier illumination as a surgical technique for RRD has the advantages of relieving the surgeon's neck pain from prolonged use of the indirect ophthalmoscope and sharing the surgical procedure with another surgical team member. In addition, fine retinal breaks that are hard to identify using an indirect ophthalmoscope can be easily found under the microscope by direct endoillumination. © 2017 The Korean Ophthalmological Society

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

In recent years, with technological advances in arthroscopy and magnetic resonance imaging and improved biomechanical studies of the meniscus, there has been some progress in the diagnosis and treatment of injuries to the roots of the meniscus. However, the biomechanical effect of posterior lateral meniscus root tears on the knee has not yet become clear. The purpose of this study was to determine the effect of a complete radial posterior lateral meniscus root tear on the knee contact mechanics and the function of the posterior meniscofemoral ligament on the knee with tear in the posterior root of lateral meniscus. A finite element model of the knee was developed to simulate different cases for intact knee, a complete radial posterior lateral meniscus root tear, a complete radial posterior lateral meniscus root tear with posterior meniscofemoral ligament deficiency, and total meniscectomy of the lateral meniscus. A compressive load of 1000 N was applied in all cases to calculate contact areas, contact pressure, and meniscal displacements. The complete radial posterior lateral meniscus root tear decreased the contact area and increased the contact pressure on the lateral compartment under compressive load. We also found a decreased contact area and increased contact pressure in the medial compartment, but it was not obvious compared to the lateral compartment. The lateral meniscus was radially displaced by compressive load after a complete radial posterior lateral meniscus root tear, and the displacement took place mainly in the body and posterior horn of lateral meniscus. There were further decrease in contact area and increases in contact pressure and raidial displacement of the lateral meniscus in the case of the complete posterior lateral meniscus root tear in combination with posterior meniscofemoral ligament deficiency. Complete radial posterior lateral meniscus root tear is not functionally equivalent to total meniscectomy. The posterior root torn lateral

Does wet hair in cold weather cause sinus headache and posterior eye pain? A possible mechanism through selective brain cooling system.

PubMed

Kaya, Abdullah; Calışkan, Halil

2012-12-01

As a general observation, wet hair in cold weather seems to be a predisposing factor for sinus headache and posterior eye pain. We offer a mechanism through selective brain cooling system for this observation. Selective brain cooling (SBC) is a mechanism to protect brain from hyperthermia. Components of SBC are head skin and upper respiratory tract (nose and paranasal sinuses). Cool venous blood from head skin and mucous membranes of nose and paranasal sinuses drains to intracranial dural sinuses and provide brain cooling. Brain will be cooled very much when head skin exposes to hypothermia such a condition like wet hair in cold weather. We suggest that, in order to reduce brain cooling activity, some alterations are being occurred within paranasal sinuses. For this purpose, sinus ostiums may close and mucus may accumulate to reduce air within sinuses. Also there may be some vasomotor changes to prevent heat loss. We hypothesize that this possible alterations may occur within paranasal sinuses as a control mechanism for brain temperature control during exposure of head skin to hypothermia. Paranasal sinuses may also cool brain directly by a very thin layer of bone separates the posterior ethmoid air sinus from the subarachnoid space and only thin plates of bone separate the sphenoidal sinuses from internal carotid artery and cavernous sinuses. Because of their critical role in the SBC, posterior ethmoid air sinus and sphenoidal sinuses may be affected from this alterations more than other paranasal sinuses. This situation may cause posterior eye pain. This mechanism can explain why a person who expose to hypothermia with wet hair or a person who don't use a beret or a hat during cold weather gets sinus headache and posterior eye pain. These symptoms could lead to an incorrect diagnosis of sinusitis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Anatomic and visual outcomes of 23-G vitrectomy without scleral buckling for primary rhegmatogenous retinal detachment.

PubMed

Figueroa, Marta S; Contreras, Inés; Noval, Susana

2013-01-01

To evaluate the anatomic success rate, visual acuity (VA) changes, and complications of 23-G vitrectomy without associated scleral procedures for the treatment of primary rhegmatogenous retinal detachment (PRRD). 
 Patients diagnosed with PRRD were considered for inclusion. Patients with evidence of proliferative vitreoretinopathy or coexisting ocular pathologies were excluded. Surgery consisted of 23-G vitrectomy with endolaser photocoagulation of retinal breaks and fluid-air-gas (12% C3F8) exchange. Minimum follow-up was 3 months. 
 A total of 133 eyes of 118 patients were included. Fifty eyes were phakic and 83 pseudophakic. Mean time from diagnosis to surgery was 6.9 days (range 1-40). Mean VA improved significantly from 20/50 (range: hand movements to 20/20) to 20/30 (range: counting fingers to 20/16), with no statistically significant differences between phakic and pseudophakic eyes (p = 0.233). Visual acuity improved to 20/40 or better in 104 eyes (78.2%). A redetachment developed in 5 eyes (3.8%), so the primary anatomic success rate was 96.2%. Four eyes required a second surgical procedure and one eye a third to achieve retinal reattachment. Cataract progression in phakic eyes made cataract surgery necessary within 1 year of vitrectomy in 12/50 (24%) eyes. Subretinal perfluoro-N-octane (PFO) was detected in 6 eyes (4.5%). 
 Twenty-three--gauge vitrectomy without scleral buckling seems to be an effective technique for the treatment of PRRD without proliferative vitreoretinopathy. The high anatomic success rate was comparable to that previously described with 20 G and scleral buckling. Complications were similar to those described for 20-G vitrectomy, except for retained subretinal PFO, which has a higher rate.

Development of diagnostic and treatment strategies for glaucoma through understanding and modification of scleral and lamina cribrosa connective tissue

PubMed Central

Quigley, Harry A.; Cone, Frances E.

2013-01-01

There is considerable evidence that the state of ocular connective tissues and their response in glaucomatous disease affects the degree of glaucoma damage. Both experimental and clinical data suggest that improved diagnostic and prognostic information could be derived from assessment of the mechanical responsiveness of the sclera and lamina cribrosa to intraocular pressure (IOP). Controlled mutagenesis of the sclera has produced a mouse strain that is relatively resistant to increased IOP. Alteration of the baseline scleral state could be accomplished through either increased cross-linking of fibrillar components or their reduction. The sclera is a dynamic structure, altering its structure and behavior in response to IOP change. The biochemical pathways that control these responses are fertile areas for new glaucoma treatments. PMID:23535950

Waardenburg syndrome: iris and choroidal hypopigmentation: findings on anterior and posterior segment imaging.

PubMed

Shields, Carol L; Nickerson, Stephanie J; Al-Dahmash, Saad; Shields, Jerry A

2013-09-01

Waardenburg syndrome typically manifests with congenital iris pigmentary abnormalities, but careful inspection can reveal additional posterior uveal pigmentary abnormalities. To demonstrate iris and choroidal hypopigmentation in patients with Waardenburg syndrome. Retrospective review of 7 patients referred for evaluation of presumed ocular melanocytosis. To describe the clinical and imaging features of the anterior and posterior uvea. In all patients, the diagnosis of Waardenburg syndrome was established. The nonocular features included white forelock in 4 of 7 (57%), tubular nose in 5 of 6 (83%), and small nasal alae in 5 of 6 (83%) patients. In 2 patients, a hearing deficit was documented on audiology testing. Family history of Waardenburg syndrome was elicited in 5 of 7 (71%) patients. Ocular features (7 patients) included telecanthus in 5 (71%), synophrys in 2 (29%), iris hypopigmentation in 5 (71%), and choroidal hypopigmentation in 5 (71%) patients. No patient had muscle contractures or Hirschsprung disease. Visual acuity was 20/20 to 20/50 in all patients. Iris hypopigmentation in 8 eyes was sector in 6 (75%) and diffuse (complete) in 2 (25%). Choroidal hypopigmentation in 9 eyes (100%) showed a sector pattern in 6 (67%) and a diffuse pattern in 3 (33%). Anterior segment optical coherence tomography revealed the hypopigmented iris to be thinner and with shallower crypts than the normal iris. Posterior segment optical coherence tomography showed a normal retina in all patients, but the subfoveal choroid in the hypopigmented region was slightly thinner (mean, 197 μm) compared with the opposite normal choroid (243 μm). Fundus autofluorescence demonstrated mild hyperautofluorescence (scleral unmasking) in hypopigmented choroid and no lipofuscin abnormality. Waardenburg syndrome manifests hypopigmentation of the iris and choroid with imaging features showing a slight reduction in the thickness of the affected tissue.

Scleral Buckling under a Slit-lamp Illumination System with a Contact Wide-angle Viewing Lens Compared with an Indirect Ophthalmoscope.

PubMed

Choi, Seung Yong; Lee, Youlim; Kim, Mirinae; Park, Young Hoon

2018-04-01

To investigate the outcomes of scleral buckling surgery performed under a slit-lamp illumination system (Visulux) with a contact wide-angle viewing lens (Mini Quad) in patients with rhegmatogenous retinal detachment (RRD) and to compare these outcomes with those of surgery performed under an indirect ophthalmoscope. By retrospective review of electronic medical records, patients with RRD who had undergone scleral buckling surgery were identified. Scleral buckling surgeries were performed with two illumination instruments, a slit-lamp (SL group) and an indirect ophthalmoscope (IO group). Subretinal fluid drainage, cryopexy, and intravitreal gas injection were performed optionally. At 6 months after surgery, anatomical and functional outcomes were evaluated and compared between the two groups. Operation time was also compared between the two groups. Of the 45 total patients (45 eyes), 28 were included in the SL group, and 17 were included in the IO group. In the SL and IO groups, the primary anatomical success rate was 89.3% and 88.2%, respectively (p = 0.92). The logarithm of the minimal angle of resolution change, which reflects improvement in best-corrected visual acuity after surgery, was -0.19 ± 0.38 in the SL group and -0.21 ± 0.63 in the IO group; this difference was not statistically significant (p = 0.91). The mean operation time was significantly shorter in the SL group (78.9 ± 11.8 minutes) than in the IO group (100.0 ± 13.9 minutes, p < 0.001), especially for patients who underwent additional procedures such as subretinal fluid drainage and cryopexy (81.4 ± 12.9 and 103.5 ± 12.3 minutes, respectively, p < 0.001). Scleral buckling surgery performed under a slit-lamp illumination system yielded a similar anatomical success rate and similar functional improvement in RRD compared with surgery performed under an indirect ophthalmoscope. The slit-lamp system could save time, especially in bullous RRD, which requires additional subretinal fluid drainage. �

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.

Extrusion of hydrogel exoplant into upper eyelid 16 years after a scleral buckle procedure

PubMed Central

Shah, Chirag P; Garg, Sunir J; Penne, Robert B

2011-01-01

Sixteen years after scleral buckle surgery with a hydrogel episcleral exoplant, a 43-year-old woman presented with progressive binocular diplopia, ptosis, and an expanding mass in her upper eyelid. She underwent surgical removal of the hydrogel exoplant through an anterior approach. The exoplant proved to be friable, fragmented, and encapsulated in a fibrous tissue; the exoplant was removed in its entirety. Postoperatively, the eyelid mass resolved, while her diplopia and ptosis improved slightly. PMID:21586850

Combined 23-gauge transconjunctival vitrectomy and scleral fixation of intraocular lens without conjunctival dissection in managing lens complications.

PubMed

Yeung, Ling; Wang, Nan-Kai; Wu, Wei-Chi; Chen, Kuan-Jen

2018-04-23

To evaluate the safety and efficacy of combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of intraocular lens (IOL) without conjunctival dissection. A retrospective study in Chang Gung Memorial Hospital, Keelung and Taoyuan, Taiwan. Patients receiving combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of IOL without conjunctival dissection were enrolled. The ocular findings, causes of lens complication, surgical procedures, type of IOL used, and complications were documented. We included 40 eyes from 39 patients (27 male, 12 female) with a mean age of 59.5 [standard deviation (±) 14.8] years old. The mean follow-up duration was 6.8 ± 5.4 months. The cause of lens complications was ocular trauma in 24 (60%) eyes, cataract surgery complications in 11 (28%) eyes, and spontaneous subluxation of crystalline lens in 5 (13%) eyes. The overall best corrected visual acuity (BCVA) (logMAR) improved from 1.359 ± 0.735 to 0.514 ± 0.582 (p < 0.001). The BCVA also improved significantly in each group with different causes of lens complications. Preoperative BCVA was the only factor associated with the postoperative visual outcome (p = 0.008). Most surgery-related complications were self-limited, including mild vitreous hemorrhage (5%), microhyphema (5%), transient elevated intraocular pressure (3%), and transient hypotony (3%). Cystoid macular edema and IOL decentration was found in 3 (8%) eyes and 1 (3%) eye respectively. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of IOL without conjunctival dissection is effective and safe in managing a wide variety of lens complications, with good postoperative comfort and visual recovery. Retrospective study, not applicable.

A comparative study of tissue glue and vicryl suture for conjunctival and scleral closure in conventional 20-gauge vitrectomy.

PubMed

Batman, C; Ozdamar, Y; Mutevelli, S; Sonmez, K; Zilelioglu, G; Karakaya, J

2009-06-01

To describe the use of tissue glue to close scleral and conjunctival wounds, and to compare the clinical outcomes using tissue glue and vicryl suture for closing these areas in conventional 20-gauge (G) vitrectomy. Thirty eyes of 30 patients were included in this study. The indications for vitreoretinal surgery were diabetic vitreous haemorrhage with severe vitreoretinal traction in 10 eyes, retinal detachment and proliferative vitreoretinopathy in 14 eyes, and vitreous opacity in 6 eyes. Tissue glue (Tisseel, Baxter AG Industries, Vienna, Austria) was used to attach scleral and conjunctival wounds in 15 eyes and vicryl sutures in 15 eyes. The patients were allotted into two subgroups as tissue glue group (TG) and vicryl suture group (VG). The sclerotomy sites were evaluated with ultrasound biomicroscopy (UBM) postoperatively in TG. Follow-up period was 2 months. The groups were statistically compared for ocular signs and symptoms by Mann-Whitney U-test. No scleral wound leakage and conjunctival reattachment were observed at the end of the surgical procedure and during the follow-up period. No adverse effects were seen in TG. Abnormal fibrous ingrowth was not detected at the sclerotomy sites by means of UBM in TG. Patient comfort was significantly higher in TG than VG (P<0.05). Tissue glue has no adverse effects on ocular tissue and can be used as a substitute for suture materials, and the use of tissue glue decreases patient symptoms during the postoperative period after 20-G vitrectomy. Tissue glue can enable to perform sutureless surgery in the conventional 20-G vitrectomy.

Glaucoma-related Changes in the Mechanical Properties and Collagen Micro-architecture of the Human Sclera

PubMed Central

Coudrillier, Baptiste; Pijanka, Jacek K.; Jefferys, Joan L.; Goel, Adhiraj; Quigley, Harry A.; Boote, Craig; Nguyen, Thao D.

2015-01-01

Objective The biomechanical behavior of the sclera determines the level of mechanical insult from intraocular pressure to the axons and tissues of the optic nerve head, as is of interest in glaucoma. In this study, we measure the collagen fiber structure and the strain response, and estimate the material properties of glaucomatous and normal human donor scleras. Methods Twenty-two posterior scleras from normal and diagnosed glaucoma donors were obtained from an eyebank. Optic nerve cross-sections were graded to determine the presence of axon loss. The specimens were subjected to pressure-controlled inflation testing. Full-field displacement maps were measured by digital image correlation (DIC) and spatially differentiated to compute surface strains. Maps of the collagen fiber structure across the posterior sclera of each inflated specimen were obtained using synchrotron wide-angle X-ray scattering (WAXS). Finite element (FE) models of the posterior scleras, incorporating a specimen-specific representation of the collagen structure, were constructed from the DIC-measured geometry. An inverse finite element analysis was developed to estimate the stiffness of the collagen fiber and inter-fiber matrix. Results The differences between glaucoma and non-glaucoma eyes were small in magnitude. Sectorial variations of degree of fiber alignment and peripapillary scleral strain significantly differed between normal and diagnosed glaucoma specimens. Meridional strains were on average larger in diagnosed glaucoma eyes compared with normal specimens. Non-glaucoma specimens had on average the lowest matrix and fiber stiffness, followed by undamaged glaucoma eyes, and damaged glaucoma eyes but the differences in stiffness were not significant. Conclusion The observed biomechanical and microstructural changes could be the result of tissue remodeling occuring in glaucoma and are likely to alter the mechanical environment of the optic nerve head and contribute to axonal damage. PMID

Diffusion of macromolecules through sclera.

PubMed

Miao, Heng; Wu, Bi-Dong; Tao, Yong; Li, Xiao-Xin

2013-02-01

To quantify the in vitro permeability coefficient over different topographical locations of porcine sclera to macromolecules with different molecular weight. Fresh equatorial and posterior superotemporal porcine sclera was mounted in a two-chamber diffusion apparatus, and its permeability to fluorescein isothiocyanate (FITC)-conjugated dextrans ranging in molecular weight from 40 kDa to 150 kDa was determined by fluorescence spectrophotometry. The sclera was processed as frozen sections and viewed with a fluorescence microscope. The thickness of the area and the thickness that macromolecules enriched in the surface of sclera were measured. The permeability coefficient (Pc) of porcine sclera to macromolecules was significantly higher (40 kDa, p = 0.028; 70 kDa, p = 0.033; 150 kDa, p = 0.007) in equatorial region than posterior, which could be attributed to the significant difference of thickness (p < 0.001, Kruskal-Wallis) between them. Moreover, linear regression indicated a significant negative relationship (40 kDa, p < 0.001; 70 kDa, p = 0.015; 150 kDa, p < 0.001) between scleral permeability coefficient and thickness. Also, Pc declined significantly with increasing molecular weight (MW, p < 0.001, Kruskal-Wallis). The area that the macromolecules enriched in the scleral surface was thicker for those with larger MW (p < 0.001, Kruskal-Wallis). The maximum MW and size for equatorial and posterior superotemporal scleral tissue were 185.01 KDa and 180.42 KDa, 9.92 nm and 9.67 nm, respectively. The permeability coefficient of porcine sclera has a significant negative relationship with scleral thickness and MW of macromolecules. Larger macromolecules are more likely to accumulate in scleral surface. The difference between topographical locations may have pharmacokinetic implications when considering transscleral diffusion of macromolecules. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

Biomechanics of the Human Posterior Sclera: Age- and Glaucoma-Related Changes Measured Using Inflation Testing

PubMed Central

Coudrillier, Baptiste; Tian, Jing; Alexander, Stephen; Myers, Kristin M.; Quigley, Harry A.; Nguyen, Thao D.

2012-01-01

Purpose. The objective of this study was to measure the biomechanical response of the human posterior sclera in vitro and to estimate the effects of age and glaucoma. Methods. Scleral specimens from 22 donors with no history of glaucoma and 11 donors with a history of glaucoma were excised 3 mm posterior to the equator and affixed to an inflation chamber. Optic nerve cross-sections were graded to determine the presence of axon loss. The time-dependent inflation response was measured in a series of pressure-controlled load–unload tests to 30 mm Hg and creep tests to 15 and 30 mm Hg. Circumferential and meridional strains were computed from the digital image correlation displacements, and midposterior stresses were determined from pressure and deformed geometry. Results. Among normal specimens, older age was predictive of a stiffer response and a thinner sclera. In the age group 75 to 93, diagnosed glaucoma eyes with axon damage were thicker than normal eyes. Both damaged and undamaged glaucoma eyes had a different strain response in the peripapillary sclera characterized by a stiffer meridional response. Undamaged glaucoma eyes had slower circumferential creep rates in the peripapillary sclera than normal eyes. Glaucoma eyes were not different from normal eyes in stresses and strains in the midposterior sclera. Conclusions. The observed differences in the biomechanical response of normal and glaucoma sclera may represent baseline properties that contribute to axon damage, or may be characteristics that result from glaucomatous disease. PMID:22395883

Scleral and intraocular amoebic dissemination in Acanthamoeba keratitis.

PubMed

Arnalich-Montiel, Francisco; Jaumandreu, Laia; Leal, Marina; Valladares, Basilio; Lorenzo-Morales, Jacob

2013-12-01

To review an Acanthamoeba keratitis case series for the documented extracorneal spread of the amoeba. A retrospective review of an observational case series from a single institution. Three patients with 4 instances of microbiologically confirmed extracorneal amoebic spread were identified. Patient 1 had nodular scleritis after undergoing penetrating keratoplasty and was treated successfully with double freeze-thaw cryotherapy; patient 2 had intraocular dissemination of the amoeba detected in a retrocorneal membrane; and patient 3 had, after undergoing tectonic keratoplasty, intraocular dissemination of the amoeba that was treated successfully with intraocular and systemic voriconazole and, afterwards, a nodular scleritis treated with double freeze-thaw cryotherapy and a large-diameter corneal graft to treat corneal recurrence. Acanthamoeba can migrate to the sclera or to the intraocular tissues in some instances, such as in long-standing disease or in penetrating keratoplasty. A prompt biopsy for microbiological analysis and early treatment are required, if this is suspected. Voriconazole can be effective for intraocular invasion when used orally and intraocularly. Scleral involvement might require a surgical approach with double freeze-thaw cryotherapy to treat the localized disease.

Safety and efficacy of fibrin glue versus infinity suture in SICS with extended scleral flap

PubMed Central

Ambastha, Anita; Kusumesh, Rakhi; Bhasker, Gyan; Sinha, Bibhuti Prassan

2018-01-01

Purpose: To study the safety and efficacy of biologic fibrin glue (FG) in comparison with infinity suture in SICS with compromised scleral flap. Methods: A retrospective comparative study of patients who were treated with FG (Group A) with 10–0 nylon (Group B) as sealing agent for intraoperative compromised tunnels in SICS. Parameters noted were postoperative inflammation, wound integrity, anterior chamber (AC) depth, intraocular pressure (IOP), and surgically induced astigmatism (SIA) at postoperative day 1, 4 weeks, 6 weeks, and 6 months, respectively. Epi Info 7 software and SIA calculator, Version 2.1 were used to analyze the result. Results: We reviewed the two groups of 18 patients each and noted that there was no statistically significant difference in postoperative inflammation (P > 0.05), AC depth (P > 0.05), and IOP (P > 0.05) between both groups at each postoperative visit. One patient in Group A showed postoperative shallow AC and subconjunctival bleb. Exposed sutures causing foreign body sensation had to be removed in five patients in Group B. At the end of 6-month postoperative period, no statistically significant difference was found in SIA (P = 0.92) between the two groups. Conclusion: Biologic FG can be safely used in securing the compromised scleral incisions in SICS. It also avoids suture-related complications. PMID:29676309

[Endoscopically controlled optimization of trans-scleral suture fixation of posterior chamber lenses in the ciliary sulcus].

PubMed

Althaus, C; Sundmacher, R

1993-08-01

Two technical difficulties have to be overcome in transscleral suture fixation of posterior chamber intraocular lenses (PCL) in the ciliary sulcus: first, exact needle penetration through the sulcus, and second, exact positioning of the PCL haptics in the sulcus. Incongruence of the two may lead to long-term complications by compression or even strangulation of ciliary processes. Intraocular endoscopy was used intraoperatively to visualize the site of needle penetration and the final location of the haptics in patients. It turned out that with our previously described standard techniques the precision was far less than anticipated. Thus, new technical ways had to be sought to improve the precision of positioning. In secondary implantation without perforating keratoplasty we achieved the best results when the needle was passed ab externo before opening the eye and before anterior vitrectomy, taking advantage of a precisely prepared sclerocorneal zone. Passing the needle ab externo in an already hypotonic eyeball gives much less precise results. In combination with perforating keratoplasty with an open-sky approach, needle penetration ab interno is reliable. Correct positioning of the PCL haptics is at least as difficult as correct needle penetration, a fact which up to now has mostly been ignored. In 33 consecutively operated eyes the technique of implantation and PCL design was varied under endoscopical control.(ABSTRACT TRUNCATED AT 250 WORDS)

Knockdown of Zebrafish Lumican Gene (zlum) Causes Scleral Thinning and Increased Size of Scleral Coats*

PubMed Central

Yeh, Lung-Kun; Liu, Chia-Yang; Kao, Winston W.-Y.; Huang, Chang-Jen; Hu, Fung-Rong; Chien, Chung-Liang; Wang, I-Jong

2010-01-01

The lumican gene (lum), which encodes one of the major keratan sulfate proteoglycans (KSPGs) in the vertebrate cornea and sclera, has been linked to axial myopia in humans. In this study, we chose zebrafish (Danio rerio) as an animal model to elucidate the role of lumican in the development of axial myopia. The zebrafish lumican gene (zlum) spans ∼4.6 kb of the zebrafish genome. Like human (hLUM) and mouse (mlum), zlum consists of three exons, two introns, and a TATA box-less promoter at the 5′-flanking region of the transcription initiation site. Sequence analysis of the cDNA predicts that zLum encodes 344 amino acids. zLum shares 51% amino acid sequence identity with human lumican. Similar to hLUM and mlum, zlum mRNA is expressed in the eye and many other tissues, such as brain, muscle, and liver as well. Transgenic zebrafish harboring an enhanced GFP reporter gene construct downstream of a 1.7-kb zlum 5′-flanking region displayed enhanced GFP expression in the cornea and sclera, as well as throughout the body. Down-regulation of zlum expression by antisense zlum morpholinos manifested ocular enlargement resembling axial myopia due to disruption of the collagen fibril arrangement in the sclera and resulted in scleral thinning. Administration of muscarinic receptor antagonists, e.g. atropine and pirenzepine, effectively subdued the ocular enlargement caused by morpholinos in in vivo zebrafish larvae assays. The observation suggests that zebrafish can be used as an in vivo model for screening compounds in treating myopia. PMID:20551313

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.

Delayed manifestation of bilateral scleral thinning after I-BRITE® procedure and review of literature for cosmetic eye-whitening procedures

PubMed Central

Moshirfar, Majid; McCaughey, Michael V; Fenzl, Carlton R; Santiago-Caban, Luis; Kramer, Gregory D; Mamalis, Nick

2015-01-01

Purpose To report a case of delayed-onset bilateral scleral thinning and calcium deposition following a cosmetic ocular-whitening procedure (I-BRITE®). Methods A 33-year-old male patient with a history of right-sided ptosis repair and left-sided anterior uveitis had previously undergone bilateral I-BRITE treatment for chronic conjunctival hyperemia. Four years after the procedure, the patient was referred to our institution with bilateral scleral thinning and overlying calcific depositions. A literature review was performed through PubMed from 1980 through 2014 using the search terms ‘cosmetic’, ‘ocular’, ‘conjunctivectomy’, ‘regional conjunctivectomy’, ‘I-BRITE’, ‘eye-whitening’, ‘scleritis’, ‘necrotizing scleritis’, ‘anterior uveitis’, ‘mitomycin C’, ‘5-fluorouracil’, and ‘bevacizumab’, along with associated cross-referencing from relevant articles. Results Examination of the patient revealed bilateral necrotizing scleritis within the nasal region of both eyes. Calcified plaques were also present within the areas of scleromalacia, along with epithelial defects demonstrated with fluorescein staining. Although evidence of previous intraocular inflammation was apparent within the left eye, there were no active signs of inflammation evident within either eye on initial presentation. Complication rates reported in the literature include: scleral thinning (1.8%), calcific plaque formation (2.9%), fibrovascular proliferation (13%), diplopia (1.2%), elevation of intraocular pressure (4.2%), and recurrence of conjunctival hyperemia (2.1%). Conclusion Cosmetic ocular whitening procedures have an attendant high complication rate, and have been associated with several adverse postoperative complications, which have in turn generated several reservations regarding the veritable benefit of the procedure. Many postsurgical complications may demonstrate delayed apparition, varying from several months to several years after primary

Delayed manifestation of bilateral scleral thinning after I-BRITE(®) procedure and review of literature for cosmetic eye-whitening procedures.

PubMed

Moshirfar, Majid; McCaughey, Michael V; Fenzl, Carlton R; Santiago-Caban, Luis; Kramer, Gregory D; Mamalis, Nick

2015-01-01

To report a case of delayed-onset bilateral scleral thinning and calcium deposition following a cosmetic ocular-whitening procedure (I-BRITE(®)). A 33-year-old male patient with a history of right-sided ptosis repair and left-sided anterior uveitis had previously undergone bilateral I-BRITE treatment for chronic conjunctival hyperemia. Four years after the procedure, the patient was referred to our institution with bilateral scleral thinning and overlying calcific depositions. A literature review was performed through PubMed from 1980 through 2014 using the search terms 'cosmetic', 'ocular', 'conjunctivectomy', 'regional conjunctivectomy', 'I-BRITE', 'eye-whitening', 'scleritis', 'necrotizing scleritis', 'anterior uveitis', 'mitomycin C', '5-fluorouracil', and 'bevacizumab', along with associated cross-referencing from relevant articles. Examination of the patient revealed bilateral necrotizing scleritis within the nasal region of both eyes. Calcified plaques were also present within the areas of scleromalacia, along with epithelial defects demonstrated with fluorescein staining. Although evidence of previous intraocular inflammation was apparent within the left eye, there were no active signs of inflammation evident within either eye on initial presentation. Complication rates reported in the literature include: scleral thinning (1.8%), calcific plaque formation (2.9%), fibrovascular proliferation (13%), diplopia (1.2%), elevation of intraocular pressure (4.2%), and recurrence of conjunctival hyperemia (2.1%). Cosmetic ocular whitening procedures have an attendant high complication rate, and have been associated with several adverse postoperative complications, which have in turn generated several reservations regarding the veritable benefit of the procedure. Many postsurgical complications may demonstrate delayed apparition, varying from several months to several years after primary surgical intervention as in the case reported here.

Laser-induced scleral shrinkage for refractive surgery

NASA Astrophysics Data System (ADS)

Ren, Qiushi; Simon, Gabriel; Parel, Jean-Marie A.; Shen, Jin-Hui

1994-06-01

We investigate the laser refractive scleroplasty (LRS) as a potential minimal-invasive method for correcting post-operative astigmatism. The scleral shrinkage near limbus was induced on 6 cadaver eyes using a 200 micrometers fiber optic probe coupled to a pulsed Ho:YAG laser. The diameter of the treatment spot was 0.8 mm. The output energy measured at tip was 60.2+/- 0.6 mJ. The treatments consisted of multiple sector patterns placed along the major axis of astigmatism parallel to the limbus, and round patterns placed along the limbus. Three treatment spots were applied on each side of the sector. The separation among sectors and limbus is 1 mm. Keratometry and topography of the cornea were measured after each sector or round pattern treatment. Effect of 5 and 10 pulses at each treatment spot were compared. Histology was performed to evaluate laser tissue damage. The major axis of astigmatism was shifted 90 degrees after the sector pattern treatment and amount of dioptric change increased when adding a new treatment or using more treatment pulses. However, the spherical equivalent of the eyes was essentially unchanged. The keratometry of the corneas remained the same after the round pattern treatment. Laser refractive scleroplasty may be applied for the correction of post-operative astigmatism.

Power Profiles and In Vitro Optical Quality of Scleral Contact Lenses: Effect of the Aperture and Power.

PubMed

Domínguez-Vicent, Alberto; Esteve-Taboada, Jose Juan; Recchioni, Alberto; Brautaset, Rune

2018-05-01

To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture. The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF). A convolution of each lens PSF with an eye-chart image was also computed. The optical power fluctuated less than 0.5 diopters (D) along the optical zone of each lens. However, the optical power obtained for some lenses did not match with its corresponding nominal one, the maximum difference being 0.5 D. In optical quality, small differences were obtained among all lenses within the same design. Although significant differences were obtained among lenses (P<0.05), these showed small impact in the image quality of each convolution. Insignificant power fluctuations were obtained along the optical zone measured for each scleral lens. Additionally, the optical quality of both lenses has showed to be independent of the lens power within the same aperture.

Masquerading Orbital Abscess Following Attempted Hydrogel Scleral Buckle Removal: Diagnostic Value of Orbital Magnetic Resonance Spectroscopy.

PubMed

Pakdel, Farzad; Hadizadeh, Homayoun; Pirmarzdashty, Niloofar; Kiavash, Victoria

2015-01-01

A 59-year-old patient developed acute proptosis, peri-orbital swelling and restriction of ocular movements 2 days after attempted scleral buckle removal. Initial clinical and orbital MRI findings were suggestive for orbital cellulitis and orbital abscess. Empiric intravenous antibiotics were not effective. Proton magnetic resonance spectroscopy (MRS) revealed a distinctive composition and helped rule out suppurative and neoplastic processes. The patient recovered soon after removing clear liquefied and tiny particles of the hydrogel buckle by an effective peristaltic technique.

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.

Vitreoretinal surgery of the posterior segment for explosive trauma in terrorist warfare.

PubMed

Bajaire, Boris; Oudovitchenko, Elena; Morales, Edgar

2006-08-01

To describe surgical management and establish anatomic and visual results of patients with explosive ocular trauma in terrorist attacks treated with extreme vitreoretinal surgery. Retrospective study of clinical records (6-month follow-up) of patients with visual acuity (VA) of light perception or better with posterior segment injuries [vitreous hemorrhage, retinal detachment (RD), intra-ocular foreign bodies (IOFB), perforating trauma (PT)] from explosive weapons who underwent vitreoretinal surgery. We reviewed the demographic characteristics, type of weapon, time between injury and surgery, VA at arrival and 6 months after surgery, and type of trauma according to the International Trauma Classification. Fifty-seven out of 236 patients with ocular injuries from explosive weapons were included in the study; all of them were military men, average age 22 years (range 16-53 years). The average time between the blast and primary closing was 1 day, and 10 days between primary closing and vitreoretinal surgery. Open traumas by laceration accounted for 96% of cases and 4% were closed traumas; 76% of the eyes had IOFB, of which 18% involved PT; 5% had endophthalmitis. Contusion was the diagnosis for 100% of the closed traumas. Of the open traumas, 40% were localized at zone I, 44% at zone II, and 16% at zone III. Upon arrival, 98% of patients had VA 20/800-LP and 2% had >20/40. The patients with closed trauma had the injuries at zone III and presented VA 20/800-LP. All patients underwent posterior vitrectomy, scleral buckling, endotaponade and when required, lensectomy (82%), IOFB removal (72%), and/or retinectomy (25%). Postoperative VA improved in 43% of the patients, stabilized in 41% and evolved to NLP in 15% of the cases. Initial expressions of ocular trauma such as RD, PT and endophthalmitis suggest bad prognosis. We presented a series of patients with severe ocular trauma of the posterior segment from explosive weapons. These patients were treated according to our

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.

Combined use of leptin and mechanical stress has osteogenic effects on ossification of the posterior longitudinal ligament.

PubMed

Chen, Shuai; Zhu, Haifeng; Wang, Gangliang; Xie, Ziang; Wang, Jiying; Chen, Jian

2018-06-16

To evaluate the effects of leptin/leptin receptor (LepR) combined with mechanical stress on the development of ossification of the posterior longitudinal ligament (OPLL), which is a disease characterized by ectopic bone formation of the posterior longitudinal ligament (PLL) and can lead to radiculopathy and myelopathy. Six human samples of the PLL were analyzed for the expression of leptin and LepR by RT-PCR and western blotting. PLL cells were stimulated with leptin and mechanical stress delivered via a Flexcell tension system, and osteogenic differentiation was evaluated by RT-PCR and western blotting analysis of osteogenic marker expression as well as by alkaline phosphatase (ALP) staining and alizarin red S staining. Activation of mitogen-activated protein kinase (MAPK), Janus kinase (JAK) 2-signal transducer, activator of transcription (STAT) 3 and phosphatidylinositol 3-kinase (PI3K)-Akt was evaluated by western blotting. Samples from the OPLL group had higher LepR mRNA and protein levels and lower leptin levels than those from healthy controls. Exposure to leptin and Flexcell increased the number of ALP-positive cells and calcium nodules in a dose-dependent manner; this effect was accompanied by upregulation of the osteogenic markers osteocalcin, runt-related transcription factor 2 (RUNX2) and osteopontin. Extracellular signal-regulated kinase, P38 MAPK, JAK2, STAT3, PI3K and Akt signaling, was also activated by the combined effects of leptin and mechanical stress. Leptin and LepR are differentially expressed in OPLL tissues, and the combined use of leptin/LepR and mechanical stress promotes osteogenic differentiation of PLL cells via MAPK, JAK2-STAT3 and PI3K/Akt signaling. These slides can be retrieved under Electronic Supplementary Material.

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

Assessing the changes in the spatial stiffness of the posterior sclera as a function of IOP with air-pulse OCE

NASA Astrophysics Data System (ADS)

Singh, Manmohan; Nair, Achuth; Aglyamov, Salavat R.; Wu, Chen; Han, Zhaolong; Lafon, Ericka; Larin, Kirill V.

2017-02-01

The mechanophysiology of tissues in the posterior eye have been implicated for diseases such as myopia and glaucoma. For example, the eye-globe shape, and consequently optical axial length, can be affected by scleral stiffness. In glaucoma, an elevated intraocular pressure is the primary risk factor for glaucoma, which is the 2nd most prevalent known cause of blindness. Recent work has shown that biomechanical properties of the optic nerve are critical for the onset and progression of glaucoma because weak tissues cause large displacements in the optic nerve, causing tissue damage. In this work, we utilize air-pulse optical coherence elastography (OCE) to quantify the spatial distribution of biomechanical properties of the optic nerve, its surrounding tissues, and the posterior sclera. Air-pulse measurements were made in a grid on in situ porcine eyes in the whole eye-globe configuration as various IOPs. The OCE-measured displacement process was linked to tissue stiffness by a simple kinematic equation. The results show that the optic nerve and peripapillary sclera are much stiffer than the surrounding sclera, and the stiffness of the optic nerve and peripapillary sclera increased as a function of IOP. However, the stiffness of the surrounding sclera did not dramatically increase. Our results show that understanding the dynamics of the biomechanical properties of the eye are critical to understand the aforementioned diseases and may provide additional information for assessing visual health and integrity.

Anterior-Posterior Cerebral Blood Volume Gradient in Human Subiculum

PubMed Central

Talati, Pratik; Rane, Swati; Kose, Samet; Gore, John; Heckers, Stephan

2014-01-01

The human hippocampal formation is characterized by anterior-posterior gradients of cell density, neurochemistry and hemodynamics. In addition, some functions are associated with specific subfields (subiculum, CA1–4, dentate gyrus) and regions (anterior and posterior). We performed contrast-enhanced, high-resolution T1-weighted 3T steady state (SS) imaging to investigate cerebral blood volume (CBV) gradients of the hippocampal formation. We studied 14 healthy subjects and found significant CBV gradients (anterior > posterior) in the subiculum but not in other hippocampal subfields. Since CBV is a marker of basal metabolism, these results indicate a greater baseline activity in the anterior compared to the posterior subiculum. This gradient might be related to the role of the subiculum as the main outflow station of the hippocampal formation and might have implications for the mechanisms of neuropsychiatric disorders. PMID:24677295

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.

Small-incision 4-point scleral suture fixation of a foldable hydrophilic acrylic intraocular lens in the absence of capsule support.

PubMed

Terveen, Daniel C; Fram, Nicole R; Ayres, Brandon; Berdahl, John P

2016-02-01

To determine the visual outcomes and complications of a new small-incision technique for 4-point fixation of a hydrophilic acrylic posterior chamber intraocular lens (IOL) in the absence of capsule support. Three North American tertiary referral centers and a private practice. Retrospective case series. Secondary IOL placement was performed from 2011 to 2014. Indications for surgery, clinical results, and complications were analyzed. Primary outcomes included postoperative corrected distance visual acuity (CDVA) and surgical complications. Charts of 35 patients (37 eyes) were reviewed. The mean age at surgery was 56 years, and the mean follow-up was 6 months (range 3 to 24 months). Clinical indications included a dislocated IOL (30%), ocular trauma (19%), crystalline lens subluxation (19%), uveitis-glaucoma-hyphema syndrome (5%), post-complicated cataract (8%), congenital cataract (8%), and decompensated cornea (3%). The mean CDVA improved from 20/80 preoperatively to 20/40 postoperatively (P < .01). Thirty-six eyes (97%) had an improved or unchanged CDVA, and 1 eye (3%) had a reduced CDVA because of worsening glaucoma. Postoperative complications included ocular hypertension (24%), iritis (5%), wound leakage (3%), transient corneal edema (3%), glaucoma requiring a tube shunt (3%), and IOL dislocation (3%). Small-incision 4-point scleral fixation of the Akreos AO60 hydrophilic acrylic IOL in the absence of capsule support appears to be a safe and effective technique for secondary IOL placement. Drs. Berdahl and Ayres are consultants to Bausch & Lomb, Inc. Drs. Ayres and Fram have received speaker fees from Bausch & Lomb. Dr. Terveen does not have a financial or proprietary interest in any material or methods mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Quantification of Posterior Globe Flattening: Methodology Development and Validationc

NASA Technical Reports Server (NTRS)

Lumpkins, S. B.; Garcia, K. M.; Sargsyan, A. E.; Hamilton, D. R.; Berggren, M. D.; Antonsen, E.; Ebert, D.

2011-01-01

Microgravity exposure affects visual acuity in a subset of astronauts, and mechanisms may include structural changes in the posterior globe and orbit. Particularly, posterior globe flattening has been implicated in several astronauts. This phenomenon is known to affect some terrestrial patient populations, and has been shown to be associated with intracranial hypertension. It is commonly assessed by magnetic resonance imaging (MRI), computed tomography (CT), or B-mode ultrasound (US), without consistent objective criteria. NASA uses a semi-quantitative scale of 0-3 as part of eye/orbit MRI and US analysis for occupational monitoring purposes. The goal of this study was to initiate development of an objective quantification methodology for posterior globe flattening.

Quantification of Posterior Globe Flattening: Methodology Development and Validation

NASA Technical Reports Server (NTRS)

Lumpkins, Sarah B.; Garcia, Kathleen M.; Sargsyan, Ashot E.; Hamilton, Douglas R.; Berggren, Michael D.; Ebert, Douglas

2012-01-01

Microgravity exposure affects visual acuity in a subset of astronauts and mechanisms may include structural changes in the posterior globe and orbit. Particularly, posterior globe flattening has been implicated in the eyes of several astronauts. This phenomenon is known to affect some terrestrial patient populations and has been shown to be associated with intracranial hypertension. It is commonly assessed by magnetic resonance imaging (MRI), computed tomography (CT) or B-mode Ultrasound (US), without consistent objective criteria. NASA uses a semiquantitative scale of 0-3 as part of eye/orbit MRI and US analysis for occupational monitoring purposes. The goal of this study was ot initiate development of an objective quantification methodology to monitor small changes in posterior globe flattening.

Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma.

PubMed

Albis-Donado, Oscar; Gil-Carrasco, Félix; Romero-Quijada, Rafael; Thomas, Ravi

2010-01-01

To evaluate the results and extrusion rates of the Ahmed glaucoma valve (AGV) implantation through a needle-generated scleral tunnel, without a tube-covering patch, in children. A retrospective review of the charts of 106 Mexican children implanted with 128 AGVs operated between 1994 and 2002, with the needle track technique, at our institution, with at least six months follow up was done. Main outcome measures were intraocular pressure (IOP) control, tube extrusions or exposure and other complications. Kaplan-Meier analysis demonstrated a 96.9% survival rate at six months, 82.4% at one year, 78.7% at two years, 70% at three years and 41.6% at four years. Total success at the last follow-up (IOP between 6 and 21 mm Hg without medications) was achieved in 30 eyes (23.5%), 58 eyes (45.3%) had qualified success (only topical hypotensive drugs) and 40 eyes (31.3%) were failures. The mean pre- and post-operative IOP at the last follow up was 28.4 mmHg (SD 9.3) and 14.5 mmHg (SD 6.3), respectively. No tube extrusions or exposures were observed. Tube-related complications included five retractions, a lens touch and a transitory endothelial touch. The risk of failure increased if the eye had any complication or previous glaucoma surgeries. Medium-term IOP control in Mexican children with glaucoma can be achieved with AGV implantation using a needle-generated tunnel, without constructing a scleral flap or using a patch to cover the tube. There were no tube extrusions, nor any tube exposures with this technique.

Isolated posterior high ankle sprain: a report of three cases.

PubMed

Botchu, Rajesh; Allen, Patricia; Rennie, Winston J

2013-12-01

High ankle sprains are difficult to diagnose and account for 10% of all ankle sprains. A high index of suspicion is essential for diagnosis. High ankle sprains are managed symptomatically, with prolonged rehabilitation. The posterior inferior tibiofibular ligament is the strongest syndesmotic ligament; isolated injury of it is rare. We present 3 cases of isolated posterior high ankle sprain and discuss the relevant anatomy, mechanism of injury, and management.

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.

Rat optic nerve head anatomy within 3D histomorphometric reconstructions of normal control eyes.

PubMed

Pazos, Marta; Yang, Hongli; Gardiner, Stuart K; Cepurna, William O; Johnson, Elaine C; Morrison, John C; Burgoyne, Claude F

2015-10-01

The purpose of this study is to three-dimensionally (3D) characterize the principal macroscopic and microscopic relationships within the rat optic nerve head (ONH) and quantify them in normal control eyes. Perfusion-fixed, trephinated ONH from 8 normal control eyes of 8 Brown Norway Rats were 3D histomorphometrically reconstructed, visualized, delineated and parameterized. The rat ONH consists of 2 scleral openings, (a superior neurovascular and inferior arterial) separated by a thin connective tissue strip we have termed the "scleral sling". Within the superior opening, the nerve abuts a prominent extension of Bruch's Membrane (BM) superiorly and is surrounded by a vascular plexus, as it passes through the sclera, that is a continuous from the choroid into and through the dural sheath and contains the central retinal vein (CRV), (inferiorly). The inferior scleral opening contains the central retinal artery and three long posterior ciliary arteries which obliquely pass through the sclera to obtain the choroid. Bruch's Membrane Opening (BMO) is irregular and vertically elongated, enclosing the nerve (superiorly) and CRV and CRA (inferiorly). Overall mean BMO Depth, BMO Area, Choroidal Thickness and peripapillary Scleral Thickness were 29 μm, 56.5 × 10(3) μm(2), 57 μm and 104 μm respectively. Mean anterior scleral canal opening (ASCO) and posterior scleral canal opening (PSCO) radii were 201 ± 15 μm and 204 ± 16 μm, respectively. Mean optic nerve area at the ASCO and PSCO were 46.3 × 10(3)±4.4 × 10(3) μm(2) and 44.1 × 10(3)±4.5 × 10(3) μm(2) respectively. In conclusion, the 3D complexity of the rat ONH and the extent to which it differs from the primate have been under-appreciated within previous 2D studies. Properly understood, these anatomic differences may provide new insights into the relative susceptibilities of the rat and primate ONH to elevated intraocular pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pullout failure strength of the posterior horn of the medial meniscus with root ligament tear.

PubMed

Kim, Young-Mo; Joo, Yong-Bum

2013-07-01

To evaluate the reparability of the posterior horn of the medial meniscus with root ligament tear by measuring the actual pullout failure strength of a simple vertical suture of an arthroscopic subtotal meniscectomized posterior horn of the medial meniscus. From November 2009 to May 2010, nine posterior horns of the medial meniscus specimens were collected from arthroscopic subtotal meniscectomy performed as a treatment for root ligament rupture of the posterior horn of the medial meniscus. Simple vertical sutures were performed on the specimens, and pullout failure load was tested with a biaxial servohydraulic testing machine (Model 8874; Instron Corp., Norwood, MA, USA). The degree of degeneration, extrusion, and medial displacement of the medial meniscus were evaluated with magnetic resonance imaging (MRI). The Kellgren-Lawrence classification was used in standing plain radiography, and mechanical alignment was measured using orthoroentgenography. Tear morphology was classified into ligament proper type or meniscoligamentous junctional type according to the site of the torn root ligament of the posterior horn of the medial meniscus during arthroscopy. The mean pullout failure strength of the posterior horn of the medial meniscus was 71.6 ± 23.2 N (range, 41.4-107.7 N). The degree of degeneration of the posterior horn of the medial meniscus on MRI showed statistically significant correlation with pullout failure strength and Kellgren-Lawrence classification. Pullout failure strength showed correlation with mechanical alignment and Kellgren-Lawrence classification (P < 0.05). The measurement of pullout failure strength of the posterior horn of the medial meniscus with root ligament tear showed a degree of repairability. The degree of degeneration of the posterior horn of the medial meniscus on MRI showed a significant correlation with the pullout failure strength. The pullout failure strength was also not only correlated with the degree of degeneration of the

Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma

PubMed Central

Albis-Donado, Oscar; Gil-Carrasco, Félix; Romero-Quijada, Rafael; Thomas, Ravi

2010-01-01

Purpose: To evaluate the results and extrusion rates of the Ahmed glaucoma valve (AGV) implantation through a needle-generated scleral tunnel, without a tube-covering patch, in children. Materials and Methods: A retrospective review of the charts of 106 Mexican children implanted with 128 AGVs operated between 1994 and 2002, with the needle track technique, at our institution, with at least six months follow up was done. Main outcome measures were intraocular pressure (IOP) control, tube extrusions or exposure and other complications. Results: Kaplan-Meier analysis demonstrated a 96.9% survival rate at six months, 82.4% at one year, 78.7% at two years, 70% at three years and 41.6% at four years. Total success at the last follow-up (IOP between 6 and 21 mm Hg without medications) was achieved in 30 eyes (23.5%), 58 eyes (45.3%) had qualified success (only topical hypotensive drugs) and 40 eyes (31.3%) were failures. The mean pre- and post-operative IOP at the last follow up was 28.4 mmHg (SD 9.3) and 14.5 mmHg (SD 6.3), respectively. No tube extrusions or exposures were observed. Tube-related complications included five retractions, a lens touch and a transitory endothelial touch. The risk of failure increased if the eye had any complication or previous glaucoma surgeries. Conclusion: Medium-term IOP control in Mexican children with glaucoma can be achieved with AGV implantation using a needle-generated tunnel, without constructing a scleral flap or using a patch to cover the tube. There were no tube extrusions, nor any tube exposures with this technique. PMID:20689189

Sutureless closure of scleral wounds in animal models by the use of laser welded biocompatible patches

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Matteini, Paolo; Menabuoni, Luca; Lenzetti, Ivo; Pini, Roberto

2011-03-01

The common procedures used to seal the scleral or conjunctival injuries are based on the traditional suturing techniques, that may induce foreign body reaction during the follow up, with subsequent inflammation and distress for the patient. In this work we present an experimental study on the laser welding of biocompatible patches onto ocular tissues, for the closure of surgical or trauma wounds. The study was performed ex vivo in animal models (porcine eyes). A penetrating perforation of the ocular tissue was performed with a surgical knife. The wound walls were approximated, and a biocompatible patch was put onto the outer surface of the tissue, in order to completely cover the wound as a plaster. The patches were prepared with a biocompatible and biodegradable polymer, showing high mechanical strength, good elasticity, high permeability for vapour and gases and rather low biodegradation. During preparation, Indocyanine Green (ICG) was included in the biopolymeric matrix, so that the films presented high absorption at 810 nm. Effective adhesion of the membranes to the ocular tissues was obtained by using diode laser light emitted from an 810 nm diode laser and delivered by means of a 300 μm core diameter optical fiber, to produce spots of local film/tissue adhesion, due to the photothermal effect at the interface. The result is an immediate closure of the wound, thus reducing post-operative complications due to inflammation.

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.

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

Posterior composite restoration update: focus on factors influencing form and function

PubMed Central

Bohaty, Brenda S; Ye, Qiang; Misra, Anil; Sene, Fabio; Spencer, Paulette

2013-01-01

Restoring posterior teeth with resin-based composite materials continues to gain popularity among clinicians, and the demand for such aesthetic restorations is increasing. Indeed, the most common aesthetic alternative to dental amalgam is resin composite. Moderate to large posterior composite restorations, however, have higher failure rates, more recurrent caries, and increased frequency of replacement. Investigators across the globe are researching new materials and techniques that will improve the clinical performance, handling characteristics, and mechanical and physical properties of composite resin restorative materials. Despite such attention, large to moderate posterior composite restorations continue to have a clinical lifetime that is approximately one-half that of the dental amalgam. While there are numerous recommendations regarding preparation design, restoration placement, and polymerization technique, current research indicates that restoration longevity depends on several variables that may be difficult for the dentist to control. These variables include the patient’s caries risk, tooth position, patient habits, number of restored surfaces, the quality of the tooth–restoration bond, and the ability of the restorative material to produce a sealed tooth–restoration interface. Although clinicians tend to focus on tooth form when evaluating the success and failure of posterior composite restorations, the emphasis must remain on advancing our understanding of the clinical variables that impact the formation of a durable seal at the restoration–tooth interface. This paper presents an update of existing technology and underscores the mechanisms that negatively impact the durability of posterior composite restorations in permanent teeth. PMID:23750102

Scleral gene expression during recovery from myopia compared with expression during myopia development in tree shrew.

PubMed

Guo, Lin; Frost, Michael R; Siegwart, John T; Norton, Thomas T

2014-01-01

During postnatal refractive development, the sclera receives retinally generated signals that regulate its biochemical properties. Hyperopic refractive error causes the retina to produce "GO" signals that, through the direct emmetropization pathway, cause scleral remodeling that increases the axial elongation rate of the eye, reducing the hyperopia. Myopia causes the retina to generate "STOP" signals that produce scleral remodeling, slowing the axial elongation rate and reducing the myopia. Our aim was to compare the pattern of gene expression produced in the sclera by the STOP signals with the GO gene expression signature we described previously. The GO gene expression signature was produced by monocular -5 diopter (D) lens wear for 2 days (ML-2) or 4 days (ML-4); an additional "STAY" condition was examined after eyes had fully compensated for a -5 D lens after 11 days of lens wear (ML-11). After 11 days of -5 D lens wear had produced full refractive compensation, gene expression in the STOP condition was examined during recovery (without the lens) for 2 days (REC-2) or 4 days (REC-4). The untreated contralateral eyes served as a control in all groups. Two age-matched normal groups provided a comparison with the treated groups. Quantitative real-time PCR was used to measure mRNA levels for 55 candidate genes. The STAY group compensated fully for the lens (treated eye versus control eye, -5.1±0.2 D). Wearing the lens, the hyperopic signal for elongation had dissipated (-0.3±0.3 D). In the STOP groups, the refraction in the recovering eyes became less myopic relative to the control eyes (REC-2, +1.3±0.3 D; REC-4, +2.6±0.4 D). In the STAY group, three genes showed significant downregulation. However, many genes that were significantly altered in GO showed smaller, nonsignificant, expression differences in the same direction in STAY, suggesting the gene expression signature in STAY is a greatly weakened form of the GO signature. In the STOP groups, a different

Effects of poly(2-hydroxyethyl methacrylate) and poly(vinyl-pyrrolidone) hydrogel implants on myopic and normal chick sclera

PubMed Central

Su, James; Iomdina, Elena; Tarutta, Elena; Ward, Brian; Song, Jie; Wildsoet, Christine F.

2008-01-01

There has been generally little attention paid to the utilization of biomaterials as an anti-myopia treatment. The purpose of this study was to investigate whether polymeric hydrogels, either implanted or injected adjacent to the outer scleral surface, slow ocular elongation. White Leghorn (gallus gallus domesticus) chicks were used at 2 weeks of age. Chicks had either (1) strip of poly(2-hydroxyethyl methacrylate) (pHEMA) implanted monocularly against the outer sclera at the posterior pole, or (2) an in situ polymerizing gel [main ingredient: poly(vinyl-pyrrolidone) (PVP)] injected monocularly at the same location. Some of the eyes injected with the polymer were fitted with a diffuser or a −10D lens. In each experiment, ocular lengths were measured at regular intervals by high frequency A-scan ultrasonography, and chicks were sacrificed for histology at staged intervals. No in vivo signs of either orbital or ocular inflammation were observed. The pHEMA implant significantly increased scleral thickness by the third week, and the implant became encapsulated with fibrous tissue. The PVP-injected eyes left otherwise untreated, showed a significant increase in scleral thickness, due to increased chondrocyte proliferation and extracellular matrix deposition. However, there was no effect of the PVP injection on ocular elongation. In eyes wearing optical devices, there was no effect on either scleral thickness or ocular elongation. These results represent “proof of principle” that scleral growth can be manipulated without adverse inflammatory responses. However, since neither approach slowed ocular elongation, additional factors must influence scleral surface area expansion in the avian eye. PMID:19109950

Automated estimation of choroidal thickness distribution and volume based on OCT images of posterior visual section.

PubMed

Vupparaboina, Kiran Kumar; Nizampatnam, Srinath; Chhablani, Jay; Richhariya, Ashutosh; Jana, Soumya

2015-12-01

A variety of vision ailments are indicated by anomalies in the choroid layer of the posterior visual section. Consequently, choroidal thickness and volume measurements, usually performed by experts based on optical coherence tomography (OCT) images, have assumed diagnostic significance. Now, to save precious expert time, it has become imperative to develop automated methods. To this end, one requires choroid outer boundary (COB) detection as a crucial step, where difficulty arises as the COB divides the choroidal granularity and the scleral uniformity only notionally, without marked brightness variation. In this backdrop, we measure the structural dissimilarity between choroid and sclera by structural similarity (SSIM) index, and hence estimate the COB by thresholding. Subsequently, smooth COB estimates, mimicking manual delineation, are obtained using tensor voting. On five datasets, each consisting of 97 adult OCT B-scans, automated and manual segmentation results agree visually. We also demonstrate close statistical match (greater than 99.6% correlation) between choroidal thickness distributions obtained algorithmically and manually. Further, quantitative superiority of our method is established over existing results by respective factors of 27.67% and 76.04% in two quotient measures defined relative to observer repeatability. Finally, automated choroidal volume estimation, being attempted for the first time, also yields results in close agreement with that of manual methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanisms of efferent-mediated responses in the turtle posterior crista.

PubMed

Holt, Joseph C; Lysakowski, Anna; Goldberg, Jay M

2006-12-20

To study the cellular mechanisms of efferent actions, we recorded from vestibular-nerve afferents close to the turtle posterior crista while efferent fibers were electrically stimulated. Efferent-mediated responses were obtained from calyx-bearing (CD, calyx and dimorphic) afferents and from bouton (B) afferents distinguished by their neuroepithelial locations into BT units near the torus and BM units at intermediate sites. The spike discharge of CD units is strongly excited by efferent stimulation, whereas BT and BM units are inhibited, with BM units also showing a postinhibitory excitation. Synaptic activity was recorded intracellularly after spikes were blocked. Responses of BT/BM units to single efferent shocks consist of a brief depolarization followed by a prolonged hyperpolarization. Both components reflect variations in hair-cell quantal release rates and are eliminated by pharmacological antagonists of alpha9/alpha10 nicotinic receptors. Blocking calcium-dependent SK potassium channels converts the biphasic response into a prolonged depolarization. Results can be explained, as in other hair-cell systems, by the sequential activation of alpha9/alpha10 and SK channels. In BM units, the postinhibitory excitation is based on an increased rate of hair-cell quanta and depends on the preceding inhibition. There is, in addition, an efferent-mediated, direct depolarization of BT/BM and CD fibers. In CD units, it is the exclusive efferent response. Nicotinic antagonists have different effects on hair-cell efferent actions and on the direct depolarization of CD and BT/BM units. Ultrastructural studies, besides confirming the efferent innervation of type II hair cells and calyx endings, show that turtle efferents commonly contact afferent boutons terminating on type II hair cells.

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

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.

Semi-Automatic Extraction Algorithm for Images of the Ciliary Muscle

PubMed Central

Kao, Chiu-Yen; Richdale, Kathryn; Sinnott, Loraine T.; Ernst, Lauren E.; Bailey, Melissa D.

2011-01-01

Purpose To development and evaluate a semi-automatic algorithm for segmentation and morphological assessment of the dimensions of the ciliary muscle in Visante™ Anterior Segment Optical Coherence Tomography images. Methods Geometric distortions in Visante images analyzed as binary files were assessed by imaging an optical flat and human donor tissue. The appropriate pixel/mm conversion factor to use for air (n = 1) was estimated by imaging calibration spheres. A semi-automatic algorithm was developed to extract the dimensions of the ciliary muscle from Visante images. Measurements were also made manually using Visante software calipers. Interclass correlation coefficients (ICC) and Bland-Altman analyses were used to compare the methods. A multilevel model was fitted to estimate the variance of algorithm measurements that was due to differences within- and between-examiners in scleral spur selection versus biological variability. Results The optical flat and the human donor tissue were imaged and appeared without geometric distortions in binary file format. Bland-Altman analyses revealed that caliper measurements tended to underestimate ciliary muscle thickness at 3 mm posterior to the scleral spur in subjects with the thickest ciliary muscles (t = 3.6, p < 0.001). The percent variance due to within- or between-examiner differences in scleral spur selection was found to be small (6%) when compared to the variance due to biological difference across subjects (80%). Using the mean of measurements from three images achieved an estimated ICC of 0.85. Conclusions The semi-automatic algorithm successfully segmented the ciliary muscle for further measurement. Using the algorithm to follow the scleral curvature to locate more posterior measurements is critical to avoid underestimating thickness measurements. This semi-automatic algorithm will allow for repeatable, efficient, and masked ciliary muscle measurements in large datasets. PMID:21169877

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.

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.

Specification of posterior midbrain region in zebrafish neuroepithelium.

PubMed

Miyagawa, T; Amanuma, H; Kuroiwa, A; Takeda, H

1996-04-01

The developing vertebrate nervous system displays a pronounced anterior-posterior (A-P) pattern, but the mechanism that generates this pattern is poorly understood. We examined through cell-transplantation experiments, when and how the cells in the zebrafish posterior midbrain acquire regional specificity along the A-P axis as shown by pax[b] gene expression. Labelled donor cells from the presumptive midbrain region at various stages were transplanted into more anterior part of unlabelled host embryos of the same developmental stage, and the expression of pax[b] in the donor cells were examined by in situ hybridization. The results indicated that, in the cells from the presumptive midbrain region, expression of pax[b] was determined as early as the 55%-epiboly (6.5 h, early gastrulation) when the underlying hypoblastic layer reached the presumptive midbrain region. We also found that when transplanted heterotopically, anterior, but not posterior, hypoblast cells induced expression of pax[b] in the overlying ectoderm. Expression of a midbrain specific gene is determined during early gastrulation and the hypoblastic layer plays an important role in this determination process.

Adenosine receptor distribution in Rhesus monkey ocular tissue.

PubMed

Beach, Krista M; Hung, Li-Fang; Arumugam, Baskar; Smith, Earl L; Ostrin, Lisa A

2018-05-21

2a expression was higher in brain and retina, ADORA2b expression was higher in retina, and ADORA3 was higher in the choroid. In conclusion, immunohistochemistry and RT-qPCR indicated differential patterns of expression of the four adenosine receptors in the ocular tissues of the normal non-human primate. The presence of ADORs in scleral fibroblasts and the choroid may support mechanisms by which ADOR antagonists prevent myopia. The potential effects of ADOR inhibition on both anterior and posterior ocular structures warrant investigation. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

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.

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.

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

Differences in survivorship of non-posterior-stabilized compared with posterior-stabilized knee designs carry substantial economic consequences, especially with limited health-care resources. However, these comparisons have often been made between relatively small groups of patients, often with short-term follow-up, with only small differences demonstrated between the groups. The goal of this study is to compare the outcomes of non-posterior-stabilized and posterior-stabilized total knee arthroplasties with use of a unique collaboration of multiple established knee arthroplasty registries. A distributed health data network was developed by the International Consortium of Orthopaedic Registries and was used in this study to reduce barriers to participation (such as security, propriety, legal, and privacy issues) compared with a centralized data warehouse approach. The study included only replacements in osteoarthritis patients who underwent total knee procedures involving fixed-bearing devices from 2001 to 2010. The outcome of interest was time to first revision. On average, not resurfacing showed a more harmful effect than resurfacing did when posterior-stabilized and non-posterior-stabilized knee replacements were compared, while the risk of revision for posterior-stabilized compared with non-posterior-stabilized knees was highest in year zero to one, followed by year one to two, years eight through ten, and years two through eight. Posterior-stabilized knees did significantly worse than non-posterior-stabilized knees did when the patella was not resurfaced. This difference was most pronounced in the first two years (year zero to one: hazard ratio [HR] = 2.15, 95% confidence interval [CI] = 1.56 to 2.95, p < 0.001; year one to two: HR = 1.61, 95% CI = 1.48 to 1.75, p < 0.001). When the patella was resurfaced, posterior-stabilized knees did significantly worse than non-posterior-stabilized knees did. This was again most pronounced in the first two years (year zero

Flashes and floaters: a survey of Canadian ophthalmology residents' practice patterns.

PubMed

Arjmand, Parnian; Hurley, Bernard

2017-10-01

Residents are often the first point of contact in assessing patients who present with "flashes and floaters" in the emergency ophthalmology clinic. Most often, these symptoms are attributed to a posterior vitreous detachment (PVD), which may be associated with a retinal tear in up to 14% of cases. A proper peripheral retinal exam is, thus, imperative, and techniques other than scleral depression may not be sufficient. We conducted a cross-sectional survey of Canadian ophthalmology residents-in-training to understand the current resident practice patterns for examination of the peripheral retina. Anonymous electronic survey of all Canadian ophthalmology residents (postgraduate years 2-5). On average, residents (n = 47) perform a peripheral retinal examination 5 to 7 times per day in the emergency clinic and on call. Reported techniques for assessing the peripheral retina include scleral depression with indirect ophthalmoscopy alone (45.7%), scleral depression combined with the 3-mirror (15.2%) or panretinal lens (10.9%), or each of these techniques alone (23.9% and 4.3%, respectively). The major factors deterring resident use of scleral depression include history of recent trauma (47.5%), patient discomfort (16.3%), personal discomfort (16.3%), or lack of time (13.8%). Although scleral depression is the recommended standard of care for assessment of flashes and floaters, residents in training may routinely use alternative techniques as a result of extrinsic and intrinsic factors. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Alveolar ridge expansion-assisted orthodontic space closure in the mandibular posterior region.

PubMed

Ozer, Mete; Akdeniz, Berat Serdar; Sumer, Mahmut

2013-12-01

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region.

The eye of the magellanic penguin (Spheniscus magellanicus): structure of the anterior segment.

PubMed

Suburo, A M; Scolaro, J A

1990-11-01

We undertook a light and scanning electron microscopic study of the eye in the Magellanic penguin (Spheniscus magellanicus). The anatomical peculiarities of the eyeball shape in Sphenisciformes have been previously described by others; here, we show that they are accompanied by several modifications in the organization of the anterior segment of the eye. The main change was found in the portion of opaque sclera extending from the cornea to the anterior border of the scleral ossicles, which was much broader than in other avian eyes. This scleral region was made of a very dense fibrous tissue and was as difficult to cut as the ossicles. The corneo-scleral boundary was also different from that of other birds, since the aqueous humor channel and the pectinate ligament were located 1.0-1.5 mm posterior to the cornea. The osseous ring was formed by 13 bones, including three pairs of over- and underplates. There was a single ciliary muscle, with meridionally oriented striated fibers. They were inserted on a circumference along the boundary between the fibrous sclera and the ossicles, far away from the wall of the aqueous humor channel. On their posterior end, the muscle fibers formed a tendinous structure attached to the inner surface of the sclera and to the outer surface of the ciliary body. Only short zonular fibrils were observed. These anatomical features are probably relevant for the adaptation of penguin eyes to vision on land and in the aquatic environment.

Muscle complex saving posterior sagittal anorectoplasty.

PubMed

Zaiem, Maher; Zaiem, Feras

2017-05-01

Posterior sagittal anorectoplasty (PSARP) published by DeVries and Peña in 1982 had become the preferred surgical technique for the management of anorectal malformations (ARM). The original technique is based upon complete exposure of the anorectal region by means of a median sagittal incision that runs from the sacrum to the anal dimple, cutting through all muscle structures behind the rectum by dividing the levator muscle and the muscle complex. Then, the rectum is located in front of the levator and within the limits of the muscle complex. In this review, we described Muscle Complex Saving-Posterior Sagittal Anorectoplasty (MCS-PSARP), which is a less invasive technique that consists of keeping this funnel-shaped muscle complex completely intact and not divided, and pulling the rectum through this funnel, toward fixing the new anus to the skin. This technique aimed both to respect the lower part of the sphincter mechanism consisting of the muscle complex, and to avoid the disturbance of this important structure by dividing and resuturing it. We presented six cases of male patients who were born with anorectal malformation (ARM) and underwent MCS-PSARP. The surgical technique proved to be feasible to achieve the dissection of the rectal pouch and the division of the rectourethral fistula in all patients, by opening only the upper part of the sphincter mechanism, the levator muscle, and keeping the lower part consisting of intact muscle complex. The early results in our series are encouraging; however, long-term functional outcomes of these patients are awaited. The surgical tips were also discussed. This proposed approach in the management of anorectal malformation cases provides an opportunity to maximize preservation of the existing continence mechanisms. It preserves the muscle complex components of the levator muscle intact, allowing a better function of the continence mechanism. Copyright © 2016 Elsevier Inc. All rights reserved.

Advances of optical coherence tomography in myopia and pathologic myopia

PubMed Central

Ng, D S C; Cheung, C Y L; Luk, F O; Mohamed, S; Brelen, M E; Yam, J C S; Tsang, C W; Lai, T Y Y

2016-01-01

The natural course of high-axial myopia is variable and the development of pathologic myopia is not fully understood. Advancements in optical coherence tomography (OCT) technology have revealed peculiar intraocular structures in highly myopic eyes and unprecedented pathologies that cause visual impairment. New OCT findings include posterior precortical vitreous pocket and precursor stages of posterior vitreous detachment; peripapillary intrachoroidal cavitation; morphological patterns of scleral inner curvature and dome-shaped macula. Swept source OCT is capable of imaging deeper layers in the posterior pole for investigation of optic nerve pits, stretched and thinned lamina cribrosa, elongated dural attachment at posterior scleral canal, and enlargement of retrobulbar subarachnoid spaces. This has therefore enabled further evaluation of various visual field defects in high myopia and the pathogenesis of glaucomatous optic neuropathy. OCT has many potential clinical uses in managing visual impairing conditions in pathologic myopia. Understanding how retinal nerve fibers are redistributed in axial elongation will allow the development of auto-segmentation software for diagnosis and monitoring progression of glaucoma. OCT is indispensable in the diagnosis of various conditions associated with myopic traction maculopathy and monitoring of post-surgical outcomes. In addition, OCT is commonly used in the multimodal imaging assessment of myopic choroidal neovascularization. Biometry and topography of the retinal layers and choroid will soon be validated for the classification of myopic maculopathy for utilization in epidemiological studies as well as clinical trials. PMID:27055674

Alveolar ridge expansion-assisted orthodontic space closure in the mandibular posterior region

PubMed Central

Akdeniz, Berat Serdar; Sumer, Mahmut

2013-01-01

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region. PMID:24396740

Tibiofemoral contact mechanics following a horizontal cleavage lesion in the posterior horn of the medial meniscus.

PubMed

Arno, Sally; Bell, Christopher P; Uquillas, Carlos; Borukhov, Ilya; Walker, Peter S

2015-04-01

The purpose of this study was to determine if a horizontal cleavage lesion (HCL) of the posterior horn of the medial meniscus would result in changes to tibiofemoral contact mechanics, as measured by peak contact pressure and contact area, which can lead to cartilage degeneration. To study this, 10 cadaveric knees were tested in a rig where forces were applied (500 N Compression, 100 N shear, 2.5 Nm Torque) and the knee dynamically flexed from -5° to 135°, as peak contact pressure and contact area were recorded. After testing of the intact knee, a horizontal cleavage lesion was created arthroscopically and testing repeated. The Wilcoxon signed-rank test was used to determine if there were differences in peak contact pressure and contact area between the intact knee and that with the HCL. A statistically significant increase in peak contact pressure of 13%, on average, and a decrease in contact area of 6%, on average, was noted following the HCL. This suggests that a horizontal cleavage lesion will result in small but statistically significant changes in tibiofemoral contact mechanics which may lead to cartilage degeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Suturing technique for scleral fixation of toric intraocular lens in the traumatic aphakic eye with corneal astigmatism.

PubMed

Pan, Qintuo; Yang, Zhengwei; Chen, Xiaomeng; Wei, Wenlong; Ke, Zhisheng; Chen, Ding; Huang, Fang; Cai, Junyong; Zhao, Zhenquan

2018-04-01

To describe the clinical outcomes of traumatic aphakic eyes with corneal astigmatism after using a novel technique for toric intraocular lens suture fixation. In total, 12 eyes of 12 patients who underwent a new scleral suture fixation technique of one-piece toric intraocular lens (SN6AT series, Alcon Inc., TX, USA) were included in our retrospective study. Preoperative patient status, postoperative visual acuity and refractive outcomes, postoperative intraocular lens rotation, tilt, decentration, and complications were analyzed. The mean follow-up was 11.6 ± 1.0 months. The mean preoperative best-corrected visual acuity was 0.55 ± 0.32 in the logarithm of minimum angle of resolution equivalent; the postoperative best-corrected visual acuity was 0.45 ± 0.34. The mean preoperative total corneal astigmatism was 2.51 ± 1.67 D. The mean postoperative residual astigmatism was 0.77 ± 0.54 D. The mean intraocular lens rotation was 3.33° ± 1.37° (range, 1°-6°). The mean intraocular lens tilt in horizontal direction was 3.64° ± 1.02° (range, 2.6°-6.3°) and in vertical direction it was 3.19° ± 1.07 ° (range, 1.6°-5.2°). The mean intraocular lens decentration in horizontal direction was 0.14 ± 0.03 mm (range, 0.089-0.192 mm) and in vertical direction it was 0.15 ± 0.02 mm (range, 0.113-0.181 mm). One patient had mild vitreous hemorrhage and two other patients had high postoperative residual sphere and astigmatism, respectively. But no other serious complications were observed. Scleral suture fixation of foldable toric intraocular lens to correct corneal astigmatism can be a safe and effective alternative technique to manage traumatic aphakic eyes that lack adequate capsular support.

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.

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

Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

PubMed

Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

2015-07-01

The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy

PubMed Central

Kaski, Diego; Yong, Keir X. X.; Paterson, Ross W.; Slattery, Catherine F.; Ryan, Natalie S.; Schott, Jonathan M.; Crutch, Sebastian J.

2015-01-01

The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal ‘visual dementia’ and most common atypical Alzheimer’s disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients’ (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer’s disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer’s disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer’s disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with ‘sticky fixation’. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer’s disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large

Regulating mechanical tension at compartment boundaries in Drosophila.

PubMed

Michel, Marcus; Dahmann, Christian

2016-10-01

During animal development, cells with similar function and fate often stay together and sort out from cells with different fates. In Drosophila wing imaginal discs, cells of anterior and posterior fates are separated by a straight compartment boundary. Separation of anterior and posterior cells requires the homeodomain-containing protein Engrailed, which is expressed in posterior cells. Engrailed induces the expression of the short-range signaling molecule Hedgehog in posterior cells and confines Hedgehog signal transduction to anterior cells. Transduction of the Hedgehog signal in anterior cells is required for the separation of anterior and posterior cells. Previous work showed that this separation of cells involves a local increase in mechanical tension at cell junctions along the compartment boundary. However, how mechanical tension was locally increased along the compartment boundary remained unknown. A recent paper now shows that the difference in Hedgehog signal transduction between anterior and posterior cells is necessary and sufficient to increase mechanical tension. The local increase in mechanical tension biases junctional rearrangements during cell intercalations to maintain the straight shape of the compartment boundary. These data highlight how developmental signals can generate patterns of mechanical tension important for tissue organization.

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

Periconal arterial anastomotic circle and posterior lumbosacral watershed zone of the spinal cord.

PubMed

Gailloud, Philippe; Gregg, Lydia; Galan, Peter; Becker, Daniel; Pardo, Carlos

2015-11-01

The existence of spinal cord watershed territories was suggested in the 1950s. Segmental infarcts within the junctional territories of adjacent radiculomedullary contributors and isolated spinal gray matter ischemia constitute two well-recognized types of watershed injury. This report describes the existence of another watershed territory related to the particular configuration of the spinal vasculature in the region of the conus medullaris. The anatomical bases underlying the concept of a posterior lumbosacral watershed zone are demonstrated with angiographic images obtained in a 16-year-old child. The clinical importance of this watershed zone is illustrated with MRI and angiographic data of three patients with a conus medullaris infarction. In all three cases of spinal ischemia an intersegmental artery providing a significant radiculomedullary contribution for the lower cord was compromised by a compressive mechanism responsible for decreased spinal cord perfusion (diaphragmatic crus syndrome in two cases, disk herniation in one). The ischemic injury, located at the junction of the anterior and posterior spinal artery territories along the dorsal aspect of the conus medullaris, was consistent with a watershed mechanism. This zone is at risk because of the caudocranial direction of flow within the most caudal segment of the posterior spinal arterial network which, from a functional standpoint, depends on the anterior spinal artery. The posterior thoracolumbar watershed zone of the spinal cord represents an area at increased risk of ischemic injury, particularly in the context of partial flow impairment related to arterial compression mechanisms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

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

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.

Mutations in FLVCR1 Cause Posterior Column Ataxia and Retinitis Pigmentosa

PubMed Central

Rajadhyaksha, Anjali M.; Elemento, Olivier; Puffenberger, Erik G.; Schierberl, Kathryn C.; Xiang, Jenny Z.; Putorti, Maria L.; Berciano, José; Poulin, Chantal; Brais, Bernard; Michaelides, Michel; Weleber, Richard G.; Higgins, Joseph J.

2010-01-01

The study of inherited retinal diseases has advanced our knowledge of the cellular and molecular mechanisms involved in sensory neural signaling. Dysfunction of two specific sensory modalities, vision and proprioception, characterizes the phenotype of the rare, autosomal-recessive disorder posterior column ataxia and retinitis pigmentosa (PCARP). Using targeted DNA capture and high-throughput sequencing, we analyzed the entire 4.2 Mb candidate sequence on chromosome 1q32 to find the gene mutated in PCARP in a single family. Employing comprehensive bioinformatic analysis and filtering, we identified a single-nucleotide coding variant in the feline leukemia virus subgroup C cellular receptor 1 (FLVCR1), a gene encoding a heme-transporter protein. Sanger sequencing confirmed the FLVCR1 mutation in this family and identified different homozygous missense mutations located within the protein's transmembrane channel segment in two other unrelated families with PCARP. To determine whether the selective pathologic features of PCARP correlated with FLVCR1 expression, we examined wild-type mouse Flvcr1 mRNA levels in the posterior column of the spinal cord and the retina via quantitative real-time reverse-transcriptase PCR. The Flvcr1 mRNA levels were most abundant in the retina, followed by the posterior column of the spinal cord and other brain regions. These results suggest that aberrant FLVCR1 causes a selective degeneration of a subpopulation of neurons in the retina and the posterior columns of the spinal cord via dysregulation of heme or iron homeostasis. This finding broadens the molecular basis of sensory neural signaling to include common mechanisms that involve proprioception and vision. PMID:21070897

Hip morphology predicts posterior hip impingement in a cadaveric model.

PubMed

Morris, William Z; Fowers, Cody A; Weinberg, Douglas S; Millis, Michael B; Tu, Leigh-Anne; Liu, Raymond W

2018-05-01

Posterior hip impingement is a recently-identified cause of hip pain. The purpose of this study is to characterise posterior femoroacetabular and ischiofemoral impingement and identify its predisposing morphologic traits. Two hundred and six cadaveric hips were randomly selected and taken through controlled motion in two pure axes associated with posterior hip impingement: external rotation (through the mechanical axis) and adduction (coronal plane). The range of motion and location of impingement was noted for each specimen. Morphologic traits including femoral/acetabular version, and true neck-shaft angle (TNSA) were also measured. External rotation impingement occurred between the femoral neck and acetabulum in 83.0% of hips, and between the lesser trochanter and ischial tuberosity in 17.0%. Adduction impingement occurred between the lesser trochanter and ischial tuberosity in 78.6% of hips, and between the femoral neck and acetabulum in 21.4%. Multiple regression revealed that increased femoral/acetabular version predicted earlier external rotation and adduction impingement. Unstandardised betas ranging from -0.39 to -0.64 reflect that each degree of increased femoral/acetabular version individually accounts for a loss of external rotation or adduction of approximately half a degree before impingement ( p < 0.001 for each). Increased TNSA was associated with earlier adduction impingement only (unstandardised beta -0.35, p = 0.005). Relative femoral/acetabular anteversion was associated with earlier posterior hip impingement. Coxa valga was associated with earlier adduction impingement, but protective against external rotation impingement. These findings highlight the importance of monitoring correction during femoral/acetabular osteotomies, as overcorrection of retroversion may predispose to earlier posterior impingement.

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.

Development of the posterior neural tube in human embryos.

PubMed

Saitsu, Hirotomo; Yamada, Shigehito; Uwabe, Chigako; Ishibashi, Makoto; Shiota, Kohei

2004-12-01

Development of the posterior neural tube (PNT) in human embryos is a complicated process that involves both primary and secondary neurulation. Because normal development of the PNT is not fully understood, pathogenesis of spinal neural tube defects remains elusive. To clarify the mechanism of PNT development, we histologically examined 20 human embryos around the stage of posterior neuropore closure and found that the developing PNT can be divided into three parts: 1) the most rostral region, which corresponds to the posterior part of the primary neural tube, 2) the junctional region of the primary and secondary neural tubes, and 3) the caudal region, which emerges from the neural cord. In the junctional region, the axially-condensed mesenchyme (AM) intervened between the neural plate/tube and the notochord at the stage of posterior neuropore closure, while the notochord was directly attached to the neural plate/tube in the most rostral region. A single cavity was found to be formed in the AM as the presumptive luminal surface cells were radially aligned in the junctional region prior to the formation of the neural cord. The single cavity was continuous with the central cavity of the primary neural tube. In contrast, multiple or isolated cavities were frequently observed in the caudal region of the PNT. Our observation suggests that the junctional region of the PNT is distinct from other regions in terms of the relationship with the notochord and the mode of cavitation during secondary neurulation.

Wavefront-Guided Scleral Lens Prosthetic Device for Keratoconus

PubMed Central

Sabesan, Ramkumar; Johns, Lynette; Tomashevskaya, Olga; Jacobs, Deborah S.; Rosenthal, Perry; Yoon, Geunyoung

2016-01-01

Purpose To investigate the feasibility of correcting ocular higher order aberrations (HOA) in keratoconus (KC) using wavefront-guided optics in a scleral lens prosthetic device (SLPD). Methods Six advanced keratoconus patients (11 eyes) were fitted with a SLPD with conventional spherical optics. A custom-made Shack-Hartmann wavefront sensor was used to measure aberrations through a dilated pupil wearing the SLPD. The position of SLPD, i.e. horizontal and vertical decentration relative to the pupil and rotation were measured and incorporated into the design of the wavefront-guided optics for the customized SLPD. A submicron-precision lathe created the designed irregular profile on the front surface of the device. The residual aberrations of the same eyes wearing the SLPD with wavefront-guided optics were subsequently measured. Visual performance with natural mesopic pupil was compared between SLPDs having conventional spherical and wavefront-guided optics by measuring best-corrected high-contrast visual acuity and contrast sensitivity. Results Root-mean-square of HOA(RMS) in the 11 eyes wearing conventional SLPD with spherical optics was 1.17±0.57μm for a 6 mm pupil. HOA were effectively corrected by the customized SLPD with wavefront-guided optics and RMS was reduced 3.1 times on average to 0.37±0.19μm for the same pupil. This correction resulted in significant improvement of 1.9 lines in mean visual acuity (p<0.05). Contrast sensitivity was also significantly improved by a factor of 2.4, 1.8 and 1.4 on average for 4, 8 and 12 cycles/degree, respectively (p<0.05 for all frequencies). Although the residual aberration was comparable to that of normal eyes, the average visual acuity in logMAR with the customized SLPD was 0.21, substantially worse than normal acuity. Conclusions The customized SLPD with wavefront-guided optics corrected the HOA of advanced KC patients to normal levels and improved their vision significantly. PMID:23478630

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.

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

Unilateral abducens and bilateral facial nerve palsies associated with posterior fossa exploration surgery

PubMed Central

Khalil, Ayman; Clerkin, James; Mandiwanza, Tafadzwa; Green, Sandra; Javadpour, Mohsen

2016-01-01

Multiple cranial nerves palsies following a posterior fossa exploration confined to an extradural compartment is a rare clinical presentation. This case report describes a young man who developed a unilateral abducens and bilateral facial nerve palsies following a posterior fossa exploration confined to an extradural compartment. There are different theories to explain this presentation, but the exact mechanism remains unclear. We propose that this patient cranial nerve palsies developed following cerebrospinal fluid (CSF) leak, potentially as a consequence of rapid change in CSF dynamics. PMID:26951144

Adjunctive Local Application of Lidocaine during Scleral Buckling under General Anesthesia

PubMed Central

Dehghani, Alireza; Montazeri, Kamran; Masjedi, Amin; Karbasi, Najmeh; Ashrafi, Leila; Saeedian, Behrooz

2011-01-01

Purpose To evaluate the effect of local lidocaine application on the incidence of the oculocardiac reflex (OCR) during scleral buckling (SB) for rhegmatogenous retinal detachment (RRD) under general anesthesia. Methods In a randomized clinical trial, eyes with RRD scheduled for SB under general anesthesia were randomized to adjunctive local application of 1 ml lidocaine 2% versus normal saline to the muscles after conjunctival opening. Surgical stimulation was initiated 5 minutes afterwards. Additionally, 100 mg of lidocaine 2% was added to 50 ml of normal saline in the treatment group which was used for irrigation during surgery; control eyes were irrigated with normal saline. The incidence of the OCR, rate of postoperative nausea/vomiting (PONV), total intravenous (IV) analgesic dose, duration of surgery, and period of hospitalization were compared between the study groups. Results Thirty eyes of 30 patients including 22 (73.3%) male and 8 (26.7%) subjects with mean age of 49.4±16.3 years were operated. OCR and PONV occurred less frequently, and total intravenous analgesic dose was significantly lower in the lidocaine group (P < 0.05 for all comparisons). However, no significant difference was noted between the study groups in terms of duration of surgery and period of hospitalization. Conclusion Adjunctive local application of lidocaine during SB under GA for RRD decreases the rate of OCR and PONV, reduces the intravenous analgesic dose, but does not affect the duration of surgery or hospitalization. PMID:22454732

Adjunctive Local Application of Lidocaine during Scleral Buckling under General Anesthesia.

PubMed

Dehghani, Alireza; Montazeri, Kamran; Masjedi, Amin; Karbasi, Najmeh; Ashrafi, Leila; Saeedian, Behrooz

2011-07-01

To evaluate the effect of local lidocaine application on the incidence of the oculocardiac reflex (OCR) during scleral buckling (SB) for rhegmatogenous retinal detachment (RRD) under general anesthesia. In a randomized clinical trial, eyes with RRD scheduled for SB under general anesthesia were randomized to adjunctive local application of 1 ml lidocaine 2% versus normal saline to the muscles after conjunctival opening. Surgical stimulation was initiated 5 minutes afterwards. Additionally, 100 mg of lidocaine 2% was added to 50 ml of normal saline in the treatment group which was used for irrigation during surgery; control eyes were irrigated with normal saline. The incidence of the OCR, rate of postoperative nausea/vomiting (PONV), total intravenous (IV) analgesic dose, duration of surgery, and period of hospitalization were compared between the study groups. Thirty eyes of 30 patients including 22 (73.3%) male and 8 (26.7%) subjects with mean age of 49.4±16.3 years were operated. OCR and PONV occurred less frequently, and total intravenous analgesic dose was significantly lower in the lidocaine group (P < 0.05 for all comparisons). However, no significant difference was noted between the study groups in terms of duration of surgery and period of hospitalization. Adjunctive local application of lidocaine during SB under GA for RRD decreases the rate of OCR and PONV, reduces the intravenous analgesic dose, but does not affect the duration of surgery or hospitalization.

Grapheme-color synesthesia subtypes: Stable individual differences reflected in posterior alpha-band oscillations.

PubMed

Cohen, Michael X; Weidacker, Kathrin; Tankink, Judith; Scholte, H Steven; Rouw, Romke

2015-01-01

Grapheme-color synesthesia is a condition in which seeing letters and numbers produces sensations of colors (e.g., the letter R may elicit a sky-blue percept). Recent evidence implicates posterior parietal areas, in addition to lower-level sensory processing regions, in the neurobiological mechanisms involved in synesthesia. Furthermore, these mechanisms seem to differ for "projectors" (synesthetes who report seeing the color "out there in the real world") versus "associators" (synesthetes who report the color to be only an internal experience). Relatively little is known about possible electrophysiological characteristics of grapheme-color synesthesia. Here we used EEG to investigate functional oscillatory differences among associators, projectors, and non-synesthetes. Projectors had stronger stimulus-related alpha-band (~10 Hz) power over posterior parietal electrodes, compared to both associators and non-synesthetes. Posterior alpha activity was not statistically significantly different between associators from non-synesthetes. We also performed a test-retest assessment of the projector-associator score and found strong retest reliability, as evidenced by a correlation coefficient of .85. These findings demonstrate that the projector-associator distinction is highly reliable over time and is related to neural oscillations in the alpha band.

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.

[Acute epidural hematoma of the posterior fossa caused by forehead impact].

PubMed

Abe, S; Furukawa, K; Endo, S; Hoshi, S; Kanaya, H

1988-03-01

A rare case of acute epidural hematoma of the posterior fossa caused by forehead impact is reported. This 36-year-old man fell from a truck and hit his face. He was conscious and was brought to our center 30 minutes after the injury. On admission, a contused wound of the right forehead was noticed. He was restless and had severe pain in the neck and upper extremities. Skull X-ray showed a linear fracture of the frontal bone and computed tomography (CT) scan was normal. He continued to be restless and sudden respiratory arrest and pupillary dilation occurred 10 hours after the admission. A CT scan revealed a lenticular high density area in the left posterior fossa which extended to the supratentorial region. The 4th ventricle was compressed and displaced to the right and also the quadrigeminal and ambient cisterns were not visualized at all. Immediate surgery disclosed a 30 g epidural hematoma of the left posterior fossa and the supratentorium and the clot was completely evacuated. The source of bleeding could not be identified. Opening of the dura revealed contusion in the occipital lobe. He died on the 17th postoperative day. The possible mechanism in the production of the posterior fossa hematoma in this case is discussed.

A shift in anterior–posterior positional information underlies the fin-to-limb evolution

PubMed Central

Onimaru, Koh; Kuraku, Shigehiro; Takagi, Wataru; Hyodo, Susumu; Sharpe, James; Tanaka, Mikiko

2015-01-01

The pectoral fins of ancestral fishes had multiple proximal elements connected to their pectoral girdles. During the fin-to-limb transition, anterior proximal elements were lost and only the most posterior one remained as the humerus. Thus, we hypothesised that an evolutionary alteration occurred in the anterior–posterior (AP) patterning system of limb buds. In this study, we examined the pectoral fin development of catshark (Scyliorhinus canicula) and revealed that the AP positional values in fin buds are shifted more posteriorly than mouse limb buds. Furthermore, examination of Gli3 function and regulation shows that catshark fins lack a specific AP patterning mechanism, which restricts its expression to an anterior domain in tetrapods. Finally, experimental perturbation of AP patterning in catshark fin buds results in an expansion of posterior values and loss of anterior skeletal elements. Together, these results suggest that a key genetic event of the fin-to-limb transformation was alteration of the AP patterning network. DOI: http://dx.doi.org/10.7554/eLife.07048.001 PMID:26283004

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.

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.

Anterior-posterior regionalized gene expression in the Ciona notochord

PubMed Central

Veeman, Michael

2014-01-01

Background In the simple ascidian chordate Ciona the signaling pathways and gene regulatory networks giving rise to initial notochord induction are largely understood and the mechanisms of notochord morphogenesis are being systematically elucidated. The notochord has generally been thought of as a non-compartmentalized or regionalized organ that is not finely patterned at the level of gene expression. Quantitative imaging methods have recently shown, however, that notochord cell size, shape and behavior vary consistently along the anterior-posterior (AP) axis. Results Here we screen candidate genes by whole mount in situ hybridization for potential AP asymmetry. We identify 4 genes that show non-uniform expression in the notochord. Ezrin/radixin/moesin (ERM) is expressed more strongly in the secondary notochord lineage than the primary. CTGF is expressed stochastically in a subset of notochord cells. A novel calmodulin-like gene (BCamL) is expressed more strongly at both the anterior and posterior tips of the notochord. A TGF-β ortholog is expressed in a gradient from posterior to anterior. The asymmetries in ERM, BCamL and TGF-β expression are evident even before the notochord cells have intercalated into a single-file column. Conclusions We conclude that the Ciona notochord is not a homogeneous tissue but instead shows distinct patterns of regionalized gene expression. PMID:24288133

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.

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.

Suppression of type I collagen in human scleral fibroblasts treated with extremely low-frequency electromagnetic fields

PubMed Central

Wang, Jie; Cui, Jiefeng

2013-01-01

Purpose To investigate the expression differences of type I collagen (COL1A1) and its underlying mechanisms in human fetal scleral fibroblasts (HFSFs) that were treated with conditioned medium from retinal pigment epithelial (RPE) cells under extremely low-frequency electromagnetic fields (ELF-EMFs). Methods The ELF-EMFs used in this study were established by slidac and artificial coils. Growth of the treated HFSFs was evaluated by a cell-counting kit-8 assay. The expression of COL1A1 and matrix metalloproteinases-2 (MMP-2) in the treated HFSFs was detected by reverse transcription PCR (RT-PCR) and western blot, and the expression of transforming growth factor-β2 (TGF-β2) and basic fibroblast growth factor-2 (FGF-2) in RPE cells exposed to EMFs was detected by RT-PCR. The expression of COL1A1 and MMP-2 in HFSFs was further confirmed by immunofluorescence staining. Activation of extracellular signal-regulated kinase 1/2 (ERK1/2 also called p44/p42 mitogen-activated protein kinases [MAPK]) and p38 in HFSFs was measured by western blot. Results We found that exposure to ELF-EMFs resulted in a decreased proliferation rate of HFSFs and that addition of RPE supernatant medium could enhance this effect. Compared with that of the control cells, a significant decrease in collagen synthesis was detected in HFSFs under ELF-EMFs. However, the expression of MMP-2 was upregulated, which could be further enhanced via an RPE supernatant additive. The activities of ERK1/2 and p38 were significantly increased in HFSFs exposed to ELF-EMFs, and this effect could be enhanced by RPE supernatant medium additive. Conclusions Our results suggested that ELF-EMFs can inhibit the expression of type I collagen in HFSFs and contribute to the remodeling of the sclera. PMID:23592926

Unilateral abducens and bilateral facial nerve palsies associated with posterior fossa exploration surgery.

PubMed

Khalil, Ayman; Clerkin, James; Mandiwanza, Tafadzwa; Green, Sandra; Javadpour, Mohsen

2016-03-06

Multiple cranial nerves palsies following a posterior fossa exploration confined to an extradural compartment is a rare clinical presentation. This case report describes a young man who developed a unilateral abducens and bilateral facial nerve palsies following a posterior fossa exploration confined to an extradural compartment. There are different theories to explain this presentation, but the exact mechanism remains unclear. We propose that this patient cranial nerve palsies developed following cerebrospinal fluid (CSF) leak, potentially as a consequence of rapid change in CSF dynamics. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2016.

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

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.

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.

Silicone hydrogel mini-scleral contact lenses in early stage after corneal collagen cross-linking for keratoconus: a retrospective case series.

PubMed

Severinsky, Boris; Wajnsztajn, Denise; Frucht-Pery, Joseph

2013-11-01

 The aim was to the evaluate performance of a novel silicone hydrogel mini-scleral contact lens (SHmS) for optical correction of keratoconus in the early stages after the corneal collagen cross-linking procedure (CXL).  We retrospectively analysed the visual acuity improvement and corneal adaptation in the first 10 eyes of nine patients fitted with SHmS lenses one to 3.5 months after corneal collagen cross-linking. The lenses were designed to rest over the patients' sclera and peri-limbal cornea and vault the central cornea with minimal support over it. Visual acuities with manifest refraction and contact lenses, refractive and topographical values (Kmin and Kmax) were evaluated on lens dispensing and after six month of lens wearing. Ocular physiological responses were evaluated using the Institute of Eye Research (IER) grading scales.  SHmS fitting was performed 2.1 ± 0.97 (SD) months after collagen cross-linking. Mean follow up was 10.9 ± 4.41 months (range six to 18 months). Mean decimal visual acuity with SHmS was 0.66 ± 0.22 (approximately 6/9 Snellen fraction, range 0.3 to 0.1) or 0.75 ± 0.14 (approximately 6/8.1, range 0.5 to 1.0), when omitting two amblyopic eyes. Nine (90 per cent) eyes were successfully fitted, that is, able to wear the lenses for 10 hours per day or longer. Mean wearing time was 11.7 hours (range six to 14) per day. No corneal neovascularisation or papillary reaction was found in all fitted eyes.  SHmS contact lenses provide successful visual rehabilitation shortly after corneal collagen cross-linking. This new soft contact lens design with scleral fixation and minimal apical touch was demonstrated to be safe shortly after collagen cross-linking, as the avoidance of contact with the treated zone minimises contact lens influence on corneal recovery. © 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.

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

Human ocular torsion during parabolic flights: an analysis with scleral search coil

NASA Technical Reports Server (NTRS)

Cheung, B. S.; Money, K.; Howard, I.; Kirienko, N.; Johnson, W.; Lackner, J.; Dizio, P.; Evanoff, J.

1992-01-01

Rotation of the eyes about the visual axis is known as ocular torsion. A lateral inclination (a "roll") of the head induces ocular torsion in the opposite direction, a response known as ocular counterrolling. For six subjects, we recorded the static (head still) and dynamic (head in oscillatory roll motion) ocular torsion in normal 1 g condition and also during the microgravity and hypergravity periods of parabolic flight, using the electromagnetic scleral search coil technique. With the head still, the direction and magnitude of torsion that occurred in response to microgravity and hypergravity differed substantially from one individual to another, but there was a significant difference in torsional magnitude between the microgravity and hypergravity periods, for all static head positions including the upright position. Under normal 1 g conditions, counterrolling compensated for about 16% of (voluntary) static head roll, while dynamic counterroll was much larger, up to 36% of head roll at 0.55 Hz. With increasing frequency of head oscillation between 0.33 Hz and 0.55 Hz, the gain of counterrolling increased and there was no change in the phase relationship. The gain of dynamic counterroll (in response to voluntary head rolling) was not significantly less in hypogravity, suggesting that on the ground at these frequencies the contribution of gravity and gravity receptors to this reflex is redundant: this reflex is probably driven by the semicircular canals. In some subjects, the torsional displacement in microgravity is accompanied by micro-torsional oscillatory motion.

Posterior hip dislocation in a non-professional football player: a case report and review of the literature.

PubMed

Bakalakos, Matthaios; Benetos, Ioannis S; Rozis, Meletios; Vlamis, John; Pneumaticos, Spiros

2018-06-02

The majority of injuries during a football game are contusions, sprains and/or strains in the thigh, knee and ankle. Hip dislocations account for 2-5% of total hip dislocations, and they can be posterior or anterior. Major complications of traumatic hip dislocation include avascular necrosis of femoral head, secondary osteoarthritis, sciatic nerve injury and heterotopic ossification. On the occasion of a case of a 33-year-old football player, who suffered a posterior hip dislocation, associated with a posterior wall fracture of the acetabulum, while playing football, we review the literature and analyze the various mechanisms of injury, the possible complications and the management including surgery and rehabilitation.

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

Decrease of Prefrontal-Posterior EEG Coherence: Loose Control during Social-Emotional Stimulation

ERIC Educational Resources Information Center

Reiser, Eva M.; Schulter, Gunter; Weiss, Elisabeth M.; Fink, Andreas; Rominger, Christian; Papousek, Ilona

2012-01-01

In two experiments we aimed to investigate if individual differences in state-dependent decreases or increases of EEG coherence between prefrontal and posterior cortical regions may be indicative of a mechanism modulating the impact social-emotional information has on an individual. Two independent samples were exposed to an emotional stimulation…

The Role of the Right Posterior Parietal Cortex in Temporal Order Judgment

ERIC Educational Resources Information Center

Woo, Sung-Ho; Kim, Ki-Hyun; Lee, Kyoung-Min

2009-01-01

Perceived order of two consecutive stimuli may not correspond to the order of their physical onsets. Such a disagreement presumably results from a difference in the speed of stimulus processing toward central decision mechanisms. Since previous evidence suggests that the right posterior parietal cortex (PPC) plays a role in modulating the…

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.

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

Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty for osteoarthritis with severe varus deformity.

PubMed

Ünkar, Ethem Ayhan; Öztürkmen, Yusuf; Şükür, Erhan; Çarkçı, Engin; Mert, Murat

2017-03-01

The aim of this study was to compare the radiological and functional results of posterior cruciate ligament (PCL) - retaining and posterior-stabilized total knee arthroplasties in patients with severe varus gonarthrosis. Medical records of 112 knees of 96 patients who underwent total knee arthroplasty for severe varus (≥15°) were reviewed. PCL-retaining and PCL-stabilizing groups consisted of 58 and 54 knees, respectively. Mean follow-up time was 56.6 months (range: 24-112 months). Knee Society (KS) clinical rating system was used in clinical evaluation. Range of motion, degree of flexion contracture, postoperative alignment, and complication rates were compared between the groups. Mean preoperative mechanical tibiofemoral angle was 20.1° in varus alignment, and was restored to 4.6° in valgus postoperatively. No statistically significant differences were found between PCL-stabilizing and PCL-retaining groups when KS knee scores, function scores, and flexion arc were evaluated. Two patients in PCL-retaining group underwent revision surgery due to aseptic loosening of tibial component. One patient in PCL-stabilizing group needed arthrotomy due to patellar clunk syndrome. There were no notable differences between the 2 groups and PCL-retaining design had outcomes as good as PCL-stabilizing total knee implant in osteoarthritic knees with severe varus deformity. Level III, Therapeutic study. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Anterior-posterior regionalized gene expression in the Ciona notochord.

PubMed

Reeves, Wendy; Thayer, Rachel; Veeman, Michael

2014-04-01

In the simple ascidian chordate Ciona, the signaling pathways and gene regulatory networks giving rise to initial notochord induction are largely understood and the mechanisms of notochord morphogenesis are being systematically elucidated. The notochord has generally been thought of as a non-compartmentalized or regionalized organ that is not finely patterned at the level of gene expression. Quantitative imaging methods have recently shown, however, that notochord cell size, shape, and behavior vary consistently along the anterior-posterior (AP) axis. Here we screen candidate genes by whole mount in situ hybridization for potential AP asymmetry. We identify 4 genes that show non-uniform expression in the notochord. Ezrin/radixin/moesin (ERM) is expressed more strongly in the secondary notochord lineage than the primary. CTGF is expressed stochastically in a subset of notochord cells. A novel calmodulin-like gene (BCamL) is expressed more strongly at both the anterior and posterior tips of the notochord. A TGF-β ortholog is expressed in a gradient from posterior to anterior. The asymmetries in ERM, BCamL, and TGF-β expression are evident even before the notochord cells have intercalated into a single-file column. We conclude that the Ciona notochord is not a homogeneous tissue but instead shows distinct patterns of regionalized gene expression. Copyright © 2013 Wiley Periodicals, Inc.

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/

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

Cosmetic Preservatives as Therapeutic Corneal and Scleral Tissue Cross-Linking Agents

PubMed Central

Babar, Natasha; Kim, MiJung; Cao, Kerry; Shimizu, Yukari; Kim, Su-Young; Takaoka, Anna; Trokel, Stephen L.; Paik, David C.

2015-01-01

Purpose. Previously, aliphatic β-nitroalcohols (BNAs) have been studied as a means to chemically induce tissue cross-linking (TXL) of cornea and sclera. There are a number of related and possibly more potent agents, known as formaldehyde releasers (FARs), that are in commercial use as preservatives in cosmetics and other personal care products. The present study was undertaken in order to screen such compounds for potential clinical utility as therapeutic TXL agents. Methods. A chemical registry of 62 FARs was created from a literature review and included characteristics relevant to TXL such as molecular weight, carcinogenicity/mutagenicity, toxicity, hydrophobicity, and commercial availability. From this registry, five compounds [diazolidinyl urea (DAU), imidazolidinyl urea (IMU), sodium hydroxymethylglycinate (SMG), DMDM hydantoin (DMDM), 5-Ethyl-3,7-dioxa-1-azabicyclo [3.3.0] octane (OCT)] were selected for efficacy screening using two independent systems, an ex vivo rabbit corneal cross-linking simulation setup and incubation of cut scleral tissue pieces. Treatments were conducted at pH 7.4 or 8.5 for 30 minutes. Efficacy was evaluated using thermal denaturation temperature (Tm), and cell toxicity was studied using the trypan blue exclusion method. Results. Cross-linking effects in the five selected FARs were pH and concentration dependent. Overall, the Tm shifts were in agreement with both cornea and sclera. By comparison with BNAs previously reported upon, the FARs identified in this study were significantly more potent but with similar or better cytotoxicity. Conclusions. The FARs, a class of compounds well known to the cosmetic industry, may have utility as therapeutic TXL agents. The compounds studied thus far show promise and will be further tested. PMID:25634979

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.

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.

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.

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.

Activin- and Nodal-related factors control antero-posterior patterning of the zebrafish embryo.

PubMed

Thisse, B; Wright, C V; Thisse, C

2000-01-27

Definition of cell fates along the dorso-ventral axis depends on an antagonistic relationship between ventralizing transforming growth factor-beta superfamily members, the bone morphogenetic proteins and factors secreted from the dorsal organizer, such as Noggin and Chordin. The extracellular binding of the last group to the bone morphogenetic proteins prevents them from activating their receptors, and the relative ventralizer:antagonist ratio is thought to specify different dorso-ventral cell fates. Here, by taking advantage of a non-genetic interference method using a specific competitive inhibitor, the Lefty-related gene product Antivin, we provide evidence that cell fate along the antero-posterior axis of the zebrafish embryo is controlled by the morphogenetic activity of another transforming growth factor-beta superfamily subgroup--the Activin and Nodal-related factors. Increasing antivin doses progressively deleted posterior fates within the ectoderm, eventually resulting in the removal of all fates except forebrain and eyes. In contrast, overexpression of activin or nodal-related factors converted ectoderm that was fated to be forebrain into more posterior ectodermal or mesendodermal fates. We propose that modulation of intercellular signalling by Antivin/Activin and Nodal-related factors provides a mechanism for the graded establishment of cell fates along the antero-posterior axis of the zebrafish embryo.

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.

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

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.

Delineation of the vitreous and posterior hyaloid using bromophenol blue.

PubMed

Haritoglou, Christos; Strauss, Rupert; Priglinger, Siegfried G; Kreutzer, Thomas; Kampik, Anselm

2008-02-01

To describe visualization of the vitreous and the posterior hyaloid membrane using bromophenol blue during vitrectomy for macular hole and retinal detachment. Six patients with macular holes and four with retinal detachments were included in the study. Before and after surgery, complete clinical examination, including funduscopy and measurements of best-corrected visual acuity and intraocular pressure, was performed. Additional functional tests, such as fluorescein angiography, optical coherence tomography (Stratus OCT; Carl Zeiss Meditec, Jena, Germany, Germany), Goldmann perimetry, and multifocal electroretinography as well as photography of the posterior pole, were performed for macular hole patients. Bromophenol blue was used in concentrations of 0.2%. During macular hole surgery, the dye was injected into the air-filled globe, while during surgery for retinal detachment, the globe was partially filled with perfluorocarbon before dye injection after induction of a posterior vitreous detachment to stain the vitreous peripherally. Bromophenol blue provided sufficient staining of the attached posterior hyaloid membrane and vitreous remnants in the periphery. This was especially helpful for patients in whom a posterior vitreous detachment could not be induced mechanically by suction using the vitrectomy probe alone, as seen in three of six interventions for a macular hole in this series. In addition, staining of the vitreous or vitreous remnants in the periphery and at the vitreous base was seen in all patients and helped to completely remove the vitreous in a controlled fashion. After macular hole surgery, increase of visual acuity from 20/100 (mean) to 20/40 was seen during follow-up up to 6 months. In one case, the hole persisted and required a second operation. Finally, closure of the hole was achieved in all patients. After retinal detachment surgery, reattachment was achieved in all cases. No dye-related adverse events were seen during follow-up as shown by

Reduced modulation of scanpaths in response to task demands in posterior cortical atrophy.

PubMed

Shakespeare, Timothy J; Pertzov, Yoni; Yong, Keir X X; Nicholas, Jennifer; Crutch, Sebastian J

2015-02-01

scene perception abilities in posterior cortical atrophy and offers insights into the mechanisms by which high-level cognitive schemes interact with low-level perception. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

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

Pedicle screw fixation for isthmic spondylolisthesis: does posterior lumbar interbody fusion improve outcome over posterolateral fusion?

PubMed

La Rosa, Giovanni; Conti, Alfredo; Cacciola, Fabio; Cardali, Salvatore; La Torre, Domenico; Gambadauro, Nicola Maria; Tomasello, Francesco

2003-09-01

Posterolateral fusion involving instrumentation-assisted segmental fixation represents a valid procedure in the treatment of lumbar instability. In cases of anterior column failure, such as in isthmic spondylolisthesis, supplemental posterior lumbar interbody fusion (PLIF) may improve the fusion rate and endurance of the construct. Posterior lumbar interbody fusion is, however, a more demanding procedure and increases costs and risks of the intervention. The advantages of this technique must, therefore, be weighed against those of a simple posterior lumbar fusion. Thirty-five consecutive patients underwent pedicle screw fixation for isthmic spondylolisthesis. In 18 patients posterior lumbar fusion was performed, and in 17 patients PLIF was added. Clinical, economic, functional, and radiographic data were assessed to determine differences in clinical and functional results and biomechanical properties. At 2-year follow-up examination, the correction of subluxation, disc height, and foraminal area were maintained in the group in which a PLIF procedure was performed, but not in the posterolateral fusion-only group (p < 0.05). Nevertheless, no statistical intergroup differences were demonstrated in terms of neurological improvement (p = 1), economic (p = 0.43), or functional (p = 0.95) outcome, nor in terms of fusion rate (p = 0.49). The authors' findings support the view that an interbody fusion confers superior mechanical strength to the spinal construct; when posterolateral fusion is the sole intervention, progressive loss of the extreme correction can be expected. Such mechanical insufficiency, however, did not influence clinical outcome.

Rhegmatogenous retinal detachments associated to Stickler syndrome in a tertiary eye care center in Saudi Arabia.

PubMed

Alshahrani, Saeed T; Ghazi, Nicola G; Al-Rashaed, Saba

2016-01-01

To investigate the clinical findings and outcomes of rhegmatogenous retinal detachment (RRD) in Stickler syndrome on affected and fellow eyes that underwent prophylactic retinopexy. Chart review of 70 eyes (62 patients). Incidence of RRD, postoperative visual acuity, and risk factors were evaluated. Twenty-two patients (35%) had RRD in the fellow eye, 37% of the eyes had cataract, 93% had macular detachment, 50% had proliferative vitreoretinopathy, and 41% had posterior vitreous detachment. Success rates were: 60% of patients after scleral buckling; 57.1% after pars plana vitrectomy; and 75% after combined scleral buckling and pars plana vitrectomy. Sixty-one (93.8%) of patients had successful surgery (including second surgery). Silicone oil tamponade was significantly associated with final anatomic outcome, with a protective odds ratio of 0.11 (P=0.027). Visual acuity improved in 54% of eyes and decreased in 5%. Statistically significant associations were present for eyes with final visual acuity ≥20/200, and total retinal detachment (P<0.001); preoperative cataract (P=0.023); and proliferative vitreoretinopathy (P<0.001). RRD developed in 16/44 eyes despite laser prophylaxis. Prophylactic retinopexy was not beneficial for Stickler syndrome patients. Success of primary surgery for RRD remains low. The primary surgery should be vitrectomy combined with scleral buckling and silicone oil tamponade.

[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.

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.

Posterior Structural Brain Volumes Differ in Maltreated Youth with and without Chronic Posttraumatic Stress Disorder

PubMed Central

Bellis, Michael D. De; Hooper, Stephen R.; Chen, Steven D.; Provenzale, James M.; Boyd, Brian D.; Glessner, Christopher E.; MacFall, James R.; Payne, Martha E.; Rybczynski, Robert; Woolley, Donald P

2016-01-01

Magnetic resonance imaging (MRI) studies of maltreated children with posttraumatic stress disorder (PTSD) suggest that maltreatment-related PTSD is associated with adverse brain development. Maltreated youth resilient to chronic PTSD were not previously investigated and may elucidate neuro-mechanisms of the stress diathesis that leads to resilience to chronic PTSD. In this cross-sectional study, anatomical volumetric and corpus callosum diffusion tensor imaging measures were examined using MRI in maltreated youth with chronic PTSD (N=38), without PTSD (N=35), and non-maltreated participants (n=59). Groups were sociodemographically similar. Participants underwent assessments for strict inclusion/exclusion criteria and psychopathology. Maltreated youth with PTSD were psychobiologically different from maltreated youth without PTSD and non-maltreated controls. Maltreated youth with PTSD had smaller posterior cerebral and cerebellar gray matter volumes than maltreated youth without PTSD and non-maltreated participants. Cerebral and cerebellar gray matter volumes inversely correlated with PTSD symptoms. Posterior corpus callosum microstructure in pediatric maltreatment-related PTSD differed compared to maltreated youth without PTSD and controls. The group differences remained significant when controlling for psychopathology, numbers of Axis I disorders, and trauma load. Alterations of these posterior brain structures may result from a shared trauma related-mechanism or an inherent vulnerability that mediates the pathway from chronic PTSD to co-morbidity. PMID:26535944

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.

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.

Left hand tactile agnosia after posterior callosal lesion.

PubMed

Balsamo, Maddalena; Trojano, Luigi; Giamundo, Arcangelo; Grossi, Dario

2008-09-01

We report a patient with a hemorrhagic lesion encroaching upon the posterior third of the corpus callosum but sparing the splenium. She showed marked difficulties in recognizing objects and shapes perceived through her left hand, while she could appreciate elementary sensorial features of items tactually presented to the same hand flawlessly. This picture, corresponding to classical descriptions of unilateral associative tactile agnosia, was associated with finger agnosia of the left hand. This very unusual case report can be interpreted as an instance of disconnection syndrome, and allows a discussion of mechanisms involved in tactile object recognition.

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.

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.

Repeated posterior dislocation of total hip arthroplasty after spinal corrective long fusion with pelvic fixation.

PubMed

Furuhashi, Hiroki; Togawa, Daisuke; Koyama, Hiroshi; Hoshino, Hironobu; Yasuda, Tatsuya; Matsuyama, Yukihiro

2017-05-01

Several reports have indicated that anterior dislocation of total hip arthroplasty (THA) can be caused by spinal degenerative changes with excessive pelvic retroversion. However, no reports have indicated that posterior dislocation can be caused by fixed pelvic anteversion after corrective spine surgery. We describe a rare case experiencing repeated posterior THA dislocation that occurred at 5 months after corrective spinal long fusion with pelvic fixation. A 64-year-old woman had undergone bilateral THA at 13 years before presenting to our institution. She had been diagnosed with kyphoscoliosis and underwent three subsequent spinal surgeries after the THA. We finally performed spinal corrective long fusion from T5 to ilium with pelvic fixation (with iliac screws). Five months later, she experienced severe hip pain when she tried to stand up from the toilet, and was unable to move, due to posterior THA dislocation. Therefore, we performed closed reduction under sedation, and her left hip was easily reduced. After the reduction, she started to walk with a hip abduction brace. However, she had experienced 5 subsequent dislocations. Based on our findings and previous reports, we have hypothesized that posterior dislocation could be occurred after spinal corrective long fusion with pelvic fixation due to three mechanisms: (1) a change in the THA cup alignment before and after spinal corrective long fusion surgery, (2) decreased and fixed pelvic posterior tilt in the sitting position, or (3) the trunk's forward tilting during standing-up motion after spinopelvic fixation. Spinal long fusion with pelvic fixation could be a risk factor for posterior THA dislocation.

Polymicrobial and microsporidial keratitis in a patient using Boston scleral contact lens for Sjogren's syndrome and ocular cicatricial pemphigoid.

PubMed

Fernandes, Merle; Sharma, Savitri

2013-04-01

To report a rare case of microsporidial and polymicrobial keratitis in a patient with Sjogren's syndrome and ocular cicatricial pemphigoid. This is a descriptive case report. A 66-year-old lady diagnosed with Sjogren's syndrome (SS) and ocular cicatricial pemphigoid (OCP) presented to us with microbial keratitis after using a Boston sclera contact lens for a painful epithelial defect. After 9 days of medical treatment, she underwent therapeutic penetrating keratoplasty. 10% potassium hydroxide and calcofluor white wet mount revealed microsporidial spores. Gram positive cocci and Gram variable bacilli on Gram stain were identified as Staphylococcus epidermidis and Corynebacterium accolens in culture. Histopathological examination of the corneal tissue confirmed the presence of microsporidial spores. Microsporidal keratitis can occur in patients with severe ocular surface disease due to SS and OCP. Predisposing factors include dry eye, local and systemic immunosuppression and Boston scleral contact lens. Early surgical intervention may be needed to eradicate the infection. Copyright © 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

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

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.

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.

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.

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.

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.

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, ...

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.

[Finite element analysis of stress changes of posterior spinal pedicle screw infixation].

PubMed

Yan, Jia-Zhi; Wu, Zhi-Hong; Xu, Ri-Xin; Wang, Xue-Song; Xing, Ze-Jun; Zhao, Yu; Zhang, Jian-Guo; Shen, Jian-Xiong; Wang, Yi-Peng; Qiu, Gui-Xing

2009-01-06

To evaluate the mechanical response of L3-L4 segment after posterior interfixation with a transpedicle screw system. Spiral CT machine was used to conduct continuous parallel scan on the L3-L4 section of a 40-year-old healthy male Chinese. The image data thus obtained were introduced into MIMICS software to reconstruct the 2-D data into volume data and obtain 3-D models of every element.. Pro/3-D model construction software system was used to simulate the 3-D entity of L3-L4 fixed by screw robs through spinal pedicle via posterior approach that was introduced into the finite element software ABAQUS to construct a 3-D finite element model. The stress changes on the vertebrae and screw under the axial pressure of 0.5 mPa was analyzed. Under the evenly distributed pressure the displacement of the L4 model was 0.00125815 mm, with an error of only 0.8167% from the datum displacement. The convergence of the model was good. The stress of the fixed vertebral body, intervertebral disc, and internal fixators changed significantly. The stress concentration zone of the intervertebral disc turned from the posterolateral side to anterolateral side. The stress produced by the fixed vertebral bodies decreased significantly. Obvious stress concentration existed in the upper and lower sides of the base of screw and the fixed screw at the upper vertebral body bore greater stress than the lower vertebral body. Integration of computer aided device and finite element analysis can successfully stimulate the internal fixation of L3-IA visa posterior approach and observe the mechanic changes in the vertebral column more directly.

Is the posterior cruciate ligament necessary for medial pivot knee prostheses with regard to postoperative kinematics?

PubMed

Fang, Chao-Hua; Chang, Chia-Ming; Lai, Yu-Shu; Chen, Wen-Chuan; Song, Da-Yong; McClean, Colin J; Kao, Hao-Yuan; Qu, Tie-Bing; Cheng, Cheng-Kung

2015-11-01

Excellent clinical and kinematical performance is commonly reported after medial pivot knee arthroplasty. However, there is conflicting evidence as to whether the posterior cruciate ligament should be retained. This study simulated how the posterior cruciate ligament, post-cam mechanism and medial tibial insert morphology may affect postoperative kinematics. After the computational intact knee model was validated according to the motion of a normal knee, four TKA models were built based on a medial pivot prosthesis; PS type, modified PS type, CR type with PCL retained and CR type with PCL sacrificed. Anteroposterior translation and axial rotation of femoral condyles on the tibia during 0°-135° knee flexion were analyzed. There was no significant difference in kinematics between the intact knee model and reported data for a normal knee. In all TKA models, normal motion was almost fully restored, except for the CR type with PCL sacrificed. Sacrificing the PCL produced paradoxical anterior femoral translation and tibial external rotation during full flexion. Either the posterior cruciate ligament or post-cam mechanism is necessary for medial pivot prostheses to regain normal kinematics after total knee arthroplasty. The morphology of medial tibial insert was also shown to produce a small but noticeable effect on knee kinematics. V.

Elucidating the mechanism of posterior reversible encephalopathy syndrome: a case of transient blindness after central venous catheterization.

PubMed

Rao, Neal M; Raychev, Radoslav; Kim, Doojin; Liebeskind, David S

2012-11-01

Posterior reversible encephalopathy syndrome (PRES) is a condition characterized by reversible symptoms including headache, visual disturbances, focal neurological deficits, altered mentation, and seizures. It has been associated with circumstances that may affect the cerebrovascular system, such as hypertension, eclampsia, and immunosuppression with calcineurin inhibitors. The underlying etiology of PRES has remained unclear; however, cerebrovascular autoregulatory dysfunction, hyperperfusion, and endothelial activation have been implicated. We describe a case of a young patient with lung transplant, who presented with headache, acute binocular blindness, and seizure immediately after infusion of saline through a peripherally inserted central catheter line, which inadvertently terminated cephalad in the left internal jugular vein, near the jugular foramen. Subsequent brain magnetic resonance imaging revealed vasogenic edematous lesions in a pattern consistent with PRES--a diagnosis supported by his constellation of symptoms, history of lung transplantation on tacrolimus immunosuppression, and relative hypertension. This is the first reported case describing the development of PRES after the insertion of a peripherally inserted central catheter line. The development of PRES in a typical high-risk patient immediately after cerebral venous outflow obstruction implicates the role of the cerebral venous system and provides potential insight into the mechanism of this disorder that remains of unclear pathogenesis.

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

Thermoplastic composites for veneering posterior teeth-a feasibility study.

PubMed

Gegauff, Anthony G; Garcia, Jose L; Koelling, Kurt W; Seghi, Robert R

2002-09-01

This pilot study was conducted to explore selected commercially-available thermoplastic composites that potentially had physical properties superior to currently available dental systems for restoring esthetic posterior crowns. Polyurethane, polycarbonate, and poly(ethylene/tetrafluoroethylene) (ETFE) composites and unfilled polyurethane specimens were injection molded to produce shapes adaptive to five standardized mechanical tests. The mechanical testing included abrasive wear rate, yield strength, apparent fracture toughness (strength ratio), flexural strength, and compressive strength. Compared to commercially available dental composites, abrasion wear rates were lower for all materials tested, yield strength was greater for the filled polycarbonates and filled polyurethane resins, fracture toughness testing was invalid (strength ratios were calculated for comparison of the pilot test materials), flexural strength was roughly similar except for the filled ETFE which was significantly greater, and compressive strength was lower. Commercially available thermoplastic resin composites, such as polyurethane, demonstrate the potential for development of an artificial crown material which exceeds the mechanical properties of currently available esthetic systems, if compressive strength can be improved.

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.

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

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

Minimally invasive posterior cervical decompression using tubular retractor: The technical note and early clinical outcome

PubMed Central

Hur, Jung-Woo; Kim, Jin-Sung; Shin, Myeong-Hoon; Ryu, Kyeong-Sik

2014-01-01

Background: The aim of this work is to present a novel decompression technique that approaches cervical spine posteriorly, but through minimal invasive method using tubular retractor avoiding detachment of posterior musculature. Methods: Six patients underwent minimally invasive posterior cervical decompression using the tubular retractor system and surgical microscope. Minimally invasive access to the posterior cervical spine was performed with exposure through a paramedian muscle-splitting approach. With the assistance of a specialized tubular retraction system and deep soft tissue expansion mechanism, multilevel posterior cervical decompression could be accomplished. This approach also allows safe docking of the retractor system on the lateral mass, thus avoiding the cervical spinal canal during exposure. A standard operating microscope was used with ×10 magnification and 400 mm focal length. The hospital charts, magnetic resonance imaging studies, and follow-up records of all the patients were reviewed. Outcome was assessed by neurological status and visual analog scale (VAS) for neck and arm pain. Results: There was no significant complication related to operation. The follow-up time was 4-12 months (mean, 9 months). Muscle weakness improved in all patients; sensory deficits resolved in four patients and improved in two patients. Analysis of the mean VAS for radicular pain and VAS for neck pain showed significant improvement. Conclusions: The preliminary experiences with good clinical outcome seem to promise that this minimally invasive technique is a valid alternative option for the treatment of cervical spondylotic myelopathy. PMID:24778922

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.

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.

Muscular contraction stimulates posterior hypothalamic neurons.

PubMed

Waldrop, T G; Stremel, R W

1989-02-01

Recent studies have suggested that the subthalamic locomotor region (STLR) of the posterior hypothalamus is involved in modulating cardiorespiratory responses to feedback from contracting muscles. The purpose of this study was to determine whether neurons in this hypothalamic region alter their discharge frequency during contraction of hindlimb muscles. Stainless steel electrodes were used to record single-unit activity of STLR neurons during static and rhythmic contractions of hindlimb muscles in anesthetized cats. Recordings were also made from neurons in areas outside but surrounding the subthalamic locomotor region. Contraction of the triceps surae muscles was induced by stimulation of the peripheral cut ends of the L7 and S1 ventral roots. Both static and rhythmic contractions of the triceps surae evoked an increase in the discharge rate of the majority of the STLR cells studied. Two types of excitatory responses were observed: 1) abrupt increases in discharge frequency at the onset of muscular contraction and 2) a delayed more gradual increase in firing. Most of the cells that responded to muscular contraction could be activated by mechanical probing of the triceps surae muscles. However, the changes in discharge frequency were unrelated to changes in arterial pressure occurring during muscular contraction. Most of the neurons located outside the STLR were slightly inhibited by or did not respond to muscular contraction. Thus input from contracting muscles exerts predominantly an excitatory effect on neurons in the posterior hypothalamus. These results are consistent with other studies which have concluded that this hypothalamic site is involved in influencing the cardiorespiratory responses to muscular contraction.

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.

Bilateral Acute Subdural Hematoma from Ruptured Posterior Communicating Artery Aneurysm

PubMed Central

Boujemâa, H.; Góngora-Rivera, F.; Barragán-Campos, H.; Karachi, K.; Chiras, J.; Sourour, N.

2006-01-01

Summary Brain tumors, hematological diseases and vascular malformations like fistulas or arteriovenous malformations are the most well known causes of non-traumatic subdural hematoma (SDH) 1. Although spontaneous subdural hematoma from ruptured intracranial aneurysm has been reported 2, SDH with non radiographic evidence of subarachnoid hemorrhage is very rare 3,4. Moreover, a patient with acute and bilateral spontaneous subdural hematoma secondary to ruptured left posterior communicating artery aneurysm has not been reported to date. The clinical findings and etiologic mechanisms are discussed. PMID:20569549

Growing skull fracture of the posterior cranial fossa and of the orbital roof.

PubMed

Caffo, M; Germanò, A; Caruso, G; Meli, F; Calisto, A; Tomasello, F

2003-03-01

Growing Skull Fractures (GSF) are rare complications of head trauma, primarily reported in infancy and early childhood. GSF are commonly located on calvaria, and rarely in other locations, including the skull base. In this study, we report two cases of GSF occurring in unusual locations. The first, a 8-month old girl, with a GSF of the suboccipital posterior fossa region, and the second, a 4-year old boy with a GSF of the right orbital roof. Both cases underwent operative treatment of the GSF, with microsurgical dissection and excision of the protruding gliotic brain tissue, watertight duraplasty and autologous bone cranial repair. The authors conducted a Medline search of the relevant English literature from 1966 to 2002. From the search, three cases of suboccipital posterior fossa region GSF and twelve series of orbital GSF, describing a total of 22 cases, have been found. A survey of the pathogenic mechanisms underlying this entity in these locations is reported. A review of suboccipital posterior fossa and orbital roof GSF cases, of nosological, ophthalmological and neurological data, neuroradiological and operative findings, and results of different treatment strategies are described.

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.

The changes of lumbar muscle flexion-relaxation phenomenon due to antero-posteriorly slanted ground surfaces.

PubMed

Hu, Boyi; Ning, Xiaopeng; Dai, Fei; Almuhaidib, Ibrahim

2016-09-01

Uneven ground surface is a common occupational injury risk factor in industries such as agriculture, fishing, transportation and construction. Studies have shown that antero-posteriorly slanted ground surfaces could reduce spinal stability and increase the risk of falling. In this study, the influence of antero-posteriorly slanted ground surfaces on lumbar flexion-relaxation responses was investigated. Fourteen healthy participants performed sagittally symmetric and asymmetric trunk bending motions on one flat and two antero-posteriorly slanted surfaces (-15° (uphill facing) and 15° (downhill facing)), while lumbar muscle electromyography and trunk kinematics were recorded. Results showed that standing on a downhill facing slanted surface delays the onset of lumbar muscle flexion-relaxation phenomenon (FRP), while standing on an uphill facing ground causes lumbar muscle FRP to occur earlier. In addition, compared to symmetric bending, when performing asymmetric bending, FRP occurred earlier on the contralateral side of lumbar muscles and significantly smaller maximum lumbar flexion and trunk inclination angles were observed. Practitioner Summary: Uneven ground surface is a common risk factor among a number of industries. In this study, we investigated the influence of antero-posteriorly slanted ground surface on trunk biomechanics during trunk bending. Results showed the slanted surface alters the lumbar tissue load-sharing mechanism in both sagittally symmetric and asymmetric bending.

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.

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.

C7 pars fracture subadjacent to C7 pedicle screw instrumentation at the caudal end of a posterior cervical instrumentation construct.

PubMed

Halim, Andrea; Grauer, Jonathan

2014-07-01

We report a case of a C7 pars fracture subadjacent to C7 pedicle screw instrumentation at the caudal end of posterior cervical instrumentation construct. To date, posterior cervical instrumentation has been "off label"; however, the US Food and Drug Administration is considering approving label indication of such instrumentation for this common surgical practice. Complications related to the techniques are reported to be relatively low. We know of no previous reports of pars fractures occurring subadjacent to such instrumentation. A 43-year-old man underwent posterior C5-C7 instrumented fusion. Postoperatively, the patient experienced cervical spine injury after a mechanical fall down stairs. Work-up detected bilateral C7 pars fractures subadjacent to the posterior instrumentation construct. After we treated the pars fracture with distal extension of the posterior fusion to the level of T2, the patient progressed to union and marked improvement of initial clinical symptoms that was maintained 2.5 years after posterior instrumentation. To our knowledge, a C7 pars fracture subadjacent to posterior cervical instrumentation construct has not been reported. We hypothesize that the pars may have been vulnerable to fracture because of excessive bone resection during foraminotomy or decortication. This complication was successfully treated by extending the fusion caudally.

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

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 ...

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

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

Posterior Cruciate Ligament Injuries Associated With Military Survival Swim Training.

PubMed

Crowell, Michael S; Mason, John S; Posner, Matthew A; Haley, Chad A

2017-07-01

Posterior cruciate ligament (PCL) injuries are relatively common injuries associated with athletic activities and high-energy trauma. Posterolateral corner (PLC) injuries frequently accompany injury to the PCL. Diagnosis can be challenging and requires a comprehensive history and physical examination. Patients frequently report vague, nonspecific symptoms and the mechanism of injury is often useful in localizing injured structures. Two of the more common mechanisms for PCL injury include a direct blow to the proximal anterior tibia with the knee flexed, as well as a significant knee hyperextension injury. With a PCL tear, patients rarely describe an audible "pop" that is commonly reported in ACL injuries. On physical exam, a frequent finding in PCL tears is a loss of 10 to 20° of knee flexion. Although the most common clinical tests for PCL tears include the posterior drawer test, the posterior sag sign, and the quadriceps active test, there is a lack of high-quality diagnostic accuracy studies. Two cases of U.S. Military Academy Cadets who sustained PCL injuries while removing combat boots during military survival swim training are presented. The results of the clinical examination are accompanied by magnetic resonance imaging results and intraoperative arthroscopic images to highlight key findings. Both patients were evaluated and diagnosed with PCL injures within 10 days of their injuries. Each reported feeling/hearing a "pop," which is atypical in PCL tears. Both patients demonstrated a lack of active and passive knee flexion, which is a commonly reported impairment. One patient was managed nonsurgically with physical therapy and eventually returned to full duty without limitations 9 months after his injury. The other patient, who sustained a combined PCL-PLC injury, underwent a PCL reconstruction and PLC repair and reconstruction 8 weeks after his injury. He returned all training, with the exception of contact/collision sports, 9 months after surgery. Both

Pseudomonas aeruginosa Survival at Posterior Contact Lens Surfaces after Daily Wear

PubMed Central

Wu, Yvonne T.; Zhu, Lucia S.; Tam, K. P. Connie; Evans, David J.; Fleiszig, Suzanne M. J.

2015-01-01

Purpose Pseudomonas aeruginosa keratitis is a sight-threatening complication of contact lens wear, yet mechanisms by which lenses predispose to infection remain unclear. Here, we tested the hypothesis that tear fluid at the posterior contact lens surface can lose antimicrobial activity over time during lens wear. Methods Daily disposable lenses were worn for 1, 2, 4, 6 or 8 h immediately after removal from their packaging, or after presoaking in sterile saline for 2 days to remove packaging solution. Unworn lenses were also tested, some coated in tears “aged” in vitro for 1 or 8 h. Lenses were placed anterior surface down into tryptic soy agar cradles containing gentamicin (100µg/ml) to kill bacteria already on the lens, and posterior surfaces inoculated with gentamicin-resistant P. aeruginosa for 3 h. Surviving bacteria were enumerated by viable counts of lens homogenates. Results Posterior surfaces of lenses worn by patients for 8 h supported more P. aeruginosa growth than lenses worn for only 1 h, if lenses were presoaked prior to wear (~ 2.4-fold, p = 0.01). This increase was offset if lenses were not presoaked to remove packaging solution (p = 0.04 at 2 h and 4 h). Irrespective of presoaking, lenses worn for 8 h showed more growth on their posterior surface than unworn lenses coated with tear fluid that was “aged” for 8 h vitro (~8.6-fold, presoaked, p = 0.003: ~ 5.4-fold from packaging solution, p = 0.004). Indeed, in vitro incubation did not impact tear antimicrobial activity. Conclusions This study shows that post lens tear fluid can lose antimicrobial activity over time during contact lens wear, supporting the idea that efficient tear exchange under a lens is critical for homeostasis. Additional studies are needed to determine applicability to other lens types, wearing modalities, and relevance to contact lens-related infections. PMID:25955639

The Posterior Limb of the Internal Capsule as the Subcortical Transitional Zone of the Anterior and Posterior Circulations: Insights from Human 7T MRI.

PubMed

Kurabe, Satoshi; Okamoto, Kouichirou; Suzuki, Kiyotaka; Matsuzawa, Hisothi; Watanabe, Masaki; Suzuki, Yuji; Nakada, Tsutomu; Fujii, Yukihiko

2016-01-01

In patients with cerebral infarction, identifying the distribution of infarction and the relevant artery is essential for ascertaining the underlying vascular pathophysiological mechanisms and preventing subsequent stroke. However, visualization of the basal perforating arteries (BPAs) has had limited success, and simultaneous viewing of background anatomical structures has only rarely been attempted in living human brains. Our study aimed at identifying the BPAs with 7T MRI and evaluating their distribution in the subcortical structures, thereby showing the clinical significance of the technique. Twenty healthy subjects and 1 patient with cerebral infarction involving the posterior limb of the internal capsule (ICpost) and thalamus underwent 3-dimensional fast spoiled gradient-echo sequence as time-of-flight magnetic resonance angiography (MRA) at 7T with a submillimeter resolution. The MRA was modified to detect inflow signals from BPAs, while preserving the background anatomical signals. BPA stems and branches in the subcortical structures and their origins were identified on images, using partial maximum intensity projection in 3 dimensions. A branch of the left posterior cerebral artery (PCA) in the patient ran through both the infarcted thalamus and ICpost and was clearly the relevant artery. In 40 intact hemispheres in healthy subjects, 571 stems and 1,421 branches of BPAs were detected in the subcortical structures. No significant differences in the numbers of stems and branches were observed between the intact hemispheres. The numbers deviated even less across subjects. The distribution analysis showed that the subcortical structures of the telencephalon, such as the caudate nucleus, anterior limb of the internal capsule, and lenticular nucleus, were predominantly supplied by BPAs from the anterior circulation. In contrast, the thalamus, belonging to the diencephalon, was mostly fed by BPAs from the posterior circulation. However, compared with other

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.

Management of posterior urethral strictures secondary to pelvic fractures in children.

PubMed

al-Rifaei, M A; Gaafar, S; Abdel-Rahman, M

1991-02-01

Bulboprostatic anastomotic urethroplasty was performed in 20 children with posterior urethral strictures secondary to bony pelvic fractures. The approach was perineal in 4 children and transpubic abdominoperineal in 16, with good postoperative results in 100 and 62.5%, respectively. In some children the urethral disruption occurred within the prostate itself and not at the prostatomembranous junction. In such cases the proximal sphincteric mechanism may be at risk and immediate repair of the injury is advisable. In the case of common prostatomembranous disruption displacement of the urethra may be significant. In such cases a transpubic approach is preferable. If the proximal sphincteric mechanism is deranged, it can be managed at the same time.

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.

Tibiofemoral contact mechanics following posterior root of medial meniscus tear, repair, meniscectomy, and allograft transplantation.

PubMed

Kim, Jin Goo; Lee, Yong Seuk; Bae, Tae Soo; Ha, Jeong Ku; Lee, Dong Hoon; Kim, Young Jae; Ra, Ho Jong

2013-09-01

The purposes of this study were to evaluate the effect on tibiofemoral contact mechanics of repair of the posterior root of the medial meniscus and the effect of meniscal allograft transplantation (MAT) with medial collateral ligament (MCL) release at different flexion angles. Ten fresh-frozen human cadaveric knees (five pairs) were used. A digital pressure sensor was inserted by capsulotomy, and experiments were performed serially under the following six conditions, that is, with an intact medial meniscus (normal controls), with a root tear, after root repair, after total meniscectomy, after MAT, and after MAT plus MCL release. During each experiment, knees were positioned at 0°, 30°, 60°, and 90° of flexion, and peak pressure (kPa) and contact area (cm2) were measured. At 0° of flexion, contact pressure did not differ among the six experimental settings. However, at 30° and 60° of flexion, contact pressure differed significantly between root tear and root repair specimens (p = 0.04 and 0.03, respectively), and between total meniscectomy and MAT specimens (p = 0.02 and 0.03, respectively). On the other hand, mean contact pressures were different between normal (476.7 ± 473.1 and 573.3 ± 479.1 kPa) and root repair (575.7 ± 357.8 and 598.6 ± 415.8), and between normal and MAT (635.7 ± 437.4 and 674.3 ± 533.2). At 0°, 30°, 60°, and 90° of flexion, contact areas differed significantly between normal and total meniscectomy specimens (p = 0.02, 0.01, 0.02, and 0.02, respectively), and between MAT and total meniscectomy specimens (p = 0.03, 0.02, 0.02, and 0.03, respectively). Contact areas differed significantly between root tear and root repair specimens at 60° of flexion (p = 0.04), and between normal control and root repair specimens at 60° and 90° of flexion (p = 0.03 and 0.04, respectively). The effects of MAT plus MCL release on contact mechanics were not different from the effects of MAT alone (n.s.). Both meniscal root repair and

Posterior Rotator Cuff Strengthening Using Theraband® in a Functional Diagonal Pattern in Collegiate Baseball Pitchers

PubMed Central

Page, Phillip A.; Lamberth, John; Abadie, Ben; Boling, Robert; Collins, Robert; Linton, Russell

1993-01-01

The deceleration phase of the pitching mechanism requires forceful eccentric contraction of the posterior rotator cuff. Because traditional isotonic strengthening may not be specific to this eccentric pattern, a more effective and functional means of strengthening the posterior rotator cuff is needed. Twelve collegiate baseball pitchers performed a moderate intensity isotonic dumbbell strengthening routine for 6 weeks. Six of the 12 subjects were randomly assigned to an experimental group and placed on a Theraband® Elastic Band strengthening routine in a functional-diagonal pattern to emphasize the eccentric contraction of the posterior rotator cuff, in addition to the isotonic routine. The control group (n = 6) performed only the isotonic exercises. Both groups were evaluated on a KIN-COM® isokinetic dynamometer in a functional diagonal pattern. Pretest and posttest average eccentric force production of the posterior rotator cuff was compared at two speeds, 60 and 180°/s. Data were analyzed with an analysis of covariance at the .05 level with significance at 60°/s. Values at 180°/s, however, were not significant. Eccentric force production at 60°/s increased more during training in the experimental group (+19.8%) than in the control group (-1.6%). There was no difference in the two groups at 180°/s; both decreased (8 to 15%). Theraband was effective at 60°/s in functional eccentric strengthening of the posterior rotator cuff in the pitching shoulder. ImagesFig 1. PMID:16558251

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

Vertebral body spread in thoracolumbar burst fractures can predict posterior construct failure.

PubMed

De Iure, Federico; Lofrese, Giorgio; De Bonis, Pasquale; Cultrera, Francesco; Cappuccio, Michele; Battisti, Sofia

2018-06-01

. There were no failures of posterior fixations with preoperative spreads <42% and losses of correction (LOC)<10°, whereas spreads >62.7% required supplementary anterior supports whenever LOC>10° were recorded. Most of the patients in a "gray zone," with spreads between 42% and 62.7%, needed additional anterior supports because of clinical-radiological evidence of impending mechanical failures, which developed independently from the GKC. Preoperative kyphosis (p<.001), load sharing score (p=.002), and spread (p<.001) significantly affected the final surgical treatment (posterior or circumferential). Twenty-two years after the LSC, both improvements in spinal stabilization systems and software imaging innovations have modified surgical concepts and approach on spinal trauma care. Spread was found to be an additional tool that could help in predicting the posterior construct failure, providing an objective preoperative indicator, easily reproducible with the modern viewers for CT images. Copyright © 2017 Elsevier Inc. All rights reserved.

Choroidal and scleral mechanisms of compensation for spectacle lenses in chicks.

PubMed

Wildsoet, C; Wallman, J

1995-05-01

, moved the set-point of the visual compensatory mechanism toward hyperopia. Optic nerve section prevents myopia in response to negative lenses but not to diffusers, suggesting that compensation for hyperopia requires the central nervous system.

Neural connectivity of the posterior body of the fornix in the human brain: diffusion tensor imaging study.

PubMed

Jang, Sung Ho; Kwon, Hyeok Gyu

2013-08-09

Little is known about the neural connectivity of the fornix in the human brain. In the current study, using diffusion tensor imaging, we attempted to investigate the neural connectivity of the posterior body of the fornix in the normal human brain. A total of 43 healthy subjects were recruited for this study. DTIs were acquired using a sensitivity-encoding head coil at 1.5T. For connectivity of the posterior body of the fornix, a seed region of interest was used on the posterior body of the fornix. Connectivity was defined as the incidence of connection between the posterior body of the fornix and any neural structure of the brain at the threshold of 5, 25, and 50 streamline. At the threshold of 5, 25, and 50, the posterior body of the fornix showed connectivity to the precentral gyrus (37%, 19%, and 15%), the postcentral gyrus (25%, 11.5%, and 7%), the posterior parietal cortex (16.5%, 5%, and 5%), the brainstem (12%, 4.5%, and 3.5%), the crus of the fornix (34%, 10.5%, and 7%), the contralateral splenium of the corpus callosum (12.5%, 5%, and 0%), and the ipsilateral splenium of the CC (69.8%%, 33.7%, and 23.3%), respectively. Findings of this study showed that the posterior body of the fornix had connectivity with the cerebral cortex, the brainstem, the fornical crus, and the contralateral splenium through the splenium of the corpus callosum in normal subjects. We believe that the results of this study would be helpful in investigation of the neural network related to memory and recovery mechanisms following fornical injury in the human brain. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Transcriptomic Analysis of Compromise Between Air-Breathing and Nutrient Uptake of Posterior Intestine in Loach (Misgurnus anguillicaudatus), an Air-Breathing Fish.

PubMed

Huang, Songqian; Cao, Xiaojuan; Tian, Xianchang

2016-08-01

Dojo loach (Misgurnus anguillicaudatus) is an air-breathing fish species by using its posterior intestine to breathe on water surface. So far, the molecular mechanism about accessory air-breathing in fish is seldom addressed. Five cDNA libraries were constructed here for loach posterior intestines form T01 (the initial stage group), T02 (mid-stage of normal group), T03 (end stage of normal group), T04 (mid-stage of air-breathing inhibited group), and T05 (the end stage of air-breathing inhibited group) and subjected to perform RNA-seq to compare their transcriptomic profilings. A total of 92,962 unigenes were assembled, while 37,905 (40.77 %) unigenes were successfully annotated. 2298, 1091, and 3275 differentially expressed genes (fn1, ACE, EGFR, Pxdn, SDF, HIF, VEGF, SLC2A1, SLC5A8 etc.) were observed in T04/T02, T05/T03, and T05/T04, respectively. Expression levels of many genes associated with air-breathing and nutrient uptake varied significantly between normal and intestinal air-breathing inhibited group. Intraepithelial capillaries in posterior intestines of loaches from T05 were broken, while red blood cells were enriched at the surface of intestinal epithelial lining with 241 ± 39 cells per millimeter. There were periodic acid-schiff (PAS)-positive epithelial mucous cells in posterior intestines from both normal and air-breathing inhibited groups. Results obtained here suggested an overlap of air-breathing and nutrient uptake function of posterior intestine in loach. Intestinal air-breathing inhibition in loach would influence the posterior intestine's nutrient uptake ability and endothelial capillary structure stability. This study will contribute to our understanding on the molecular regulatory mechanisms of intestinal air-breathing in loach.

C2 spondylotic radiculopathy: the nerve root impingement mechanism investigated by para-sagittal CT/MRI, dynamic rotational CT, intraoperative microscopic findings, and treated by microscopic posterior foraminotomy.

PubMed

Fujiwara, Yasushi; Izumi, Bunichiro; Fujiwara, Masami; Nakanishi, Kazuyoshi; Tanaka, Nobuhiro; Adachi, Nobuo; Manabe, Hideki

2017-04-01

C2 radiculopathy is known to cause occipito-cervical pain, but their pathology is unclear because of its rarity and unique anatomy. In this paper, we investigated the mechanism of C2 radiculopathy that underwent microscopic cervical foraminotomies (MCF). Three cases with C2 radiculopathy treated by MCF were investigated retrospectively. The mean follow-up period was 24 months. Pre-operative symptoms, imaging studies including para-sagittal CT and MRI, rotational dynamic CT, and intraoperative findings were investigated. There were 1 male and 2 females. The age of patients were ranged from 50 to 79 years. All cases had intractable occipito-cervical pain elicited by the cervical rotation. C2 nerve root block was temporally effective. There was unilateral spondylosis in symptomatic side without obvious atlatoaxial instability. Para-sagittal MRI and CT showed severe foraminal stenosis at C1-C2 due to the bony spur derived from the lateral atlanto-axial joints. In one case, dynamic rotational CT showed that the symptomatic foramen became narrower on rotational position. MCF was performed in all cases, and the C2 nerve root was impinged between the inferior edge of the C1 posterior arch and bony spur from the C1-C2 joint. After surgery, occipito-cervical pain disappeared. This study demonstrated that mechanical impingement of the C2 nerve root is one of the causes of occipito-cervical pain and it was successfully treated by microscopic resection of the inferior edge of the C1 posterior arch. Para-sagittal CT and MRI, rotational dynamic CT, and nerve root block were effective for diagnosis.

Highly Crosslinked-remelted versus Less-crosslinked Polyethylene in Posterior Cruciate-retaining TKAs in the Same Patients.

PubMed

Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik; Lee, June-Hyung

2015-11-01

Concern regarding osteolysis attributable to polyethylene wear after TKA, particularly in younger patients, has prompted the introduction of highly crosslinked-remelted polyethylene (HXLPE) for TKAs. However, few in vivo comparative results of TKAs using HXLPE and less-crosslinked polyethylene inserts in the same patients are available, regarding fracture or failure of the locking mechanism of tibial polyethylene inserts or of osteolysis in patients younger than 60 years. We wanted to determine whether (1) survivorship free from aseptic loosening in knees with HXLPE inserts was different from survivorship in knees with less-crosslinked polyethylene inserts, (2) the prevalence of fracture or failure of the locking mechanism of the tibial polyethylene insert was greater in knees with HXLPE than in those with less-crosslinked polyethylene, and (3) the proportion of patients who had osteolysis develop was greater with HXLPE than with less-crosslinked polyethylene inserts. One hundred seventy-one patients with a mean age of 58 ± 8 years (range, 35-59 years) received posterior cruciate-retaining prostheses with a less-crosslinked polyethylene tibial insert in one knee and a HXLPE tibial insert in the contralateral knee. From January 2007 to January 2010, we performed 366 same-day bilateral simultaneous sequential posterior cruciate-retaining TKAs in 183 patients, of whom 171 (93%) participated in this study. All patients during this study period underwent posterior cruciate-retaining TKAs regardless of deformity of the knees and we did not perform posterior-stabilized TKAs during the same period. Patients who had bilateral end-stage osteoarthritis and were younger than 60 years were selected for inclusion. Six patients (4%) were lost to followup before 5 years. Twenty-six patients were males and 145 were females. The mean duration of followup was 6 years (range, 5-8 years). At each followup, patients were assessed for loosening of the components, fracture or failure of

Ketorolac-tobramycin combination vs fluorometholone-tobramycin combination in reducing inflammation following phacoemulsification cataract extraction with scleral tunnel incision.

PubMed

Guzey, M; Karadede, S; Dogan, Z; Satici, A

2000-01-01

The objective of this study was to compare the efficacy of ketorolac-tobramycin combination with fluorometholone-tobramycin combination in the control of ocular inflammation after endocapsular phacoemulsification cataract surgery with scleral tunnel incision. This was a prospective, randomized, investigator masked, 2-week, single-center study. Ocular examinations were carried out preoperatively and postoperatively on days 1 (baseline), 2, 3, 7, and 14. There were 60 patients (30 in each treatment group) undergoing uncomplicated cataract-lens implant surgery enrolled and randomized in the study. The baseline parameters were similar in the two study groups. At each visit comprehensive ocular examinations were performed and a 4-point (0 to 3) grading system was used to record findings of the burning/stinging sensation, blurred vision, ocular discomfort, conjunctival hyperemia, anterior chamber flare, and anterior chamber cells. There was no statistically significant difference between the treatment groups in the findings of the ocular inflammation at any of the postoperative visits. Both treatments were equally well tolerated. This study suggests that ketorolac may be an alternative to some corticosteroids (fluorometholone). It is generally accepted that fluorometholone is not as potent an anti-inflammatory as prednisolone the most commonly used steroid following cataract extraction.

Nanotherapy for posterior eye diseases.

PubMed

Kaur, Indu Pal; Kakkar, Shilpa

2014-11-10

It is assumed that more than 50% of the most enfeebling ocular diseases have their origin in the posterior segment. Furthermore, most of these diseases lead to partial or complete blindness, if left untreated. After cancer, blindness is the second most dreaded disease world over. However, treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted for delivery to this segment. In this regard, nanostructured drug delivery systems are proposed to defy ocular barriers, target retina, and act as permeation enhancers in addition to providing a controlled release. Since an important step towards developing effective treatment strategies is to understand the course or a route a drug molecule needs to follow to reach the target site, the first part of the present review discusses various pathways available for effective delivery to and clearance from the posterior eye. Promise held by nanocarrier systems, viz. liposomes, nanoparticles, and nanoemulsion, for effective delivery and selective targeting is also discussed with illustrative examples, tables, and flowcharts. However, the applicability of these nanocarrier systems as self-administration ocular drops is still an unrealized dream which is in itself a huge technological challenge. Copyright © 2014 Elsevier B.V. All rights reserved.

Aneurysmal subarachnoid hemorrhage with concomitant posterior communicating artery fenestration.

PubMed

Weiner, Gregory M; Grandhi, Ramesh; Zwagerman, Nathan T; Agarwal, Nitin; Friedlander, Robert M

2015-02-01

Fenestrations of the posterior communicating artery (PCoA) are extremely rare. Associated aneurysms have only been documented three times in the literature, and none associated with a subarachnoid hemorrhage. We describe a 52-year-old female who presented with a subarachnoid hemorrhage secondary to a ruptured saccular aneurysm at the proximal limb of a fenestrated right PCoA. The patient was also found to have bilateral middle cerebral artery (MCA) aneurysms. Surgical management included surmising the etiology of the subarachnoid hemorrhage with subsequent clipping of both the right PCoA and MCA aneurysm. The potential embryological mechanisms leading to a PCoA fenestration are discussed.

Posterior glenoid bone grafting in total shoulder arthroplasty for osteoarthritis with severe posterior glenoid wear.

PubMed

Nicholson, Gregory P; Cvetanovich, Gregory L; Rao, Allison J; O'Donnell, Patrick

2017-10-01

Total shoulder arthroplasty (TSA) in cases with posterior wear can be addressed by eccentric reaming of the anterior glenoid or by augmenting the posterior glenoid with bone grafting or augmented glenoid implants. We report the results of TSA with posterior glenoid bone grafting (PGBG) with humeral head autograft in patients with shoulder osteoarthritis and severe posterior glenoid wear. A retrospective review of cases from 2004 to 2014 revealed 34 patients. Preoperative and postoperative radiographs were evaluated for glenoid version and humeral head subluxation as well as component loosening. Patient-reported outcomes were compared preoperatively and postoperatively. Complications and reoperations were also evaluated. Of the 34 patients, 28 (82.4%) were available at a minimum of 2 years' follow-up. PGBG corrected glenoid retroversion from -28° ± 4° preoperatively to -4° ± 2° (P < .001). Humeral head subluxation also improved after PGBG with respect to the scapular axis and to the midglenoid face (P < .001). Radiographic analysis revealed all PGBGs had incorporated. Radiographically, 3 patients (10.7%) had a total of 5 broken or displaced screws. In addition, 3 patients (10.7%) had a broken metal marker in the center peg of the glenoid component. No patients required component revision surgery by final follow-up. Only 1 reoperation occurred for capsular release. Patients showed significant improvements in all patient-reported outcomes. Patients undergoing primary TSA with humeral head autograft PGBG showed significant improvements in glenoid version, humeral head subluxation, patient-reported outcomes, and range of motion at an average of 4 years' follow-up. There was a low revision rate and a high rate of graft incorporation. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Traumatic Posterior Atlantoaxial Dislocation Without Associated Fracture but With Neurological Deficit

PubMed Central

Xu, Yong; Li, Feng; Guan, Hanfeng; Xiong, Wei

2015-01-01

Abstract Posterior atlantoaxial dislocation without odontoid fracture is extremely rare and often results in fatal spinal cord injury. According to the reported literature, all cases presented mild or no neurologic deficit, with no definite relation to upper spinal cord injury. Little is reported about traumatic posterior atlantoaxial dislocation, with incomplete quadriplegia associated with a spinal cord injury. We present a case of posterior atlantoaxial dislocation without associated fracture, but with quadriplegia, and accompanying epidural hematoma and subarachnoid hemorrhage. The patient underwent gentle traction in the neutral position until repeated cranial computed tomography revealed no progression of the epidural hematoma. Thereafter, the atlantoaxial dislocation was reduced by using partial odontoidectomy via a video-assisted transcervical approach and maintained with posterior polyaxial screw-rod constructs and an autograft. Neurological status improved immediately after surgery, and the patient recovered completely after 1 year. Posterior fusion followed by closed reduction is the superior strategy for posterior atlantoaxial dislocation without odontoid fracture, according to literature. But for cases with severe neurological deficit, open reduction may be the safest choice to avoid the lethal complication of overdistraction of the spinal cord. Also, open reduction and posterior srew-rod fixation are safe and convenient strategies in dealing with traumatic posterior atlantoaxial dislocation patients with neurological deficit. PMID:26512572

Diagnostics for insufficiencies of posterior calculations in Bayesian signal inference.

PubMed

Dorn, Sebastian; Oppermann, Niels; Ensslin, Torsten A

2013-11-01

We present an error-diagnostic validation method for posterior distributions in Bayesian signal inference, an advancement of a previous work. It transfers deviations from the correct posterior into characteristic deviations from a uniform distribution of a quantity constructed for this purpose. We show that this method is able to reveal and discriminate several kinds of numerical and approximation errors, as well as their impact on the posterior distribution. For this we present four typical analytical examples of posteriors with incorrect variance, skewness, position of the maximum, or normalization. We show further how this test can be applied to multidimensional signals.

Subcortical mechanisms in language: lexical-semantic mechanisms and the thalamus.

PubMed

Crosson, B

1999-07-01

Four previously published cases of dominant thalamic lesion in which the author has participated are reviewed to gain a better understanding of thalamic participation in lexical-semantic functions. Naming deficits in two cases support Nadeau and Crosson's (1997) hypothesis of a selective engagement mechanism involving the frontal lobes, inferior thalamic peduncle, nucleus reticularis, and other thalamic nuclei, possibly the centromedian nucleus. This mechanism selectively engages those cortical areas required to perform a cognitive task, while maintaining other areas in a state of relative disengagement. Deficits in selective engagement disproportionately affect lexical retrieval based on semantic input, as opposed to lexical and sublexical processes, because the former is more dependent upon this attentional system. The concept of selective engagement is also useful in understanding thalamic participation in working memory, as supported by data from one recent functional neuroimaging study. Other processes also may be compromised in more posterior thalamic lesions which damage the pulvinar but not other components of this selective engagement system. A third case with aphasia after a more superior and posterior thalamic lesion also had oral reading errors similar to those in neglect dyslexia. The pattern of deficits suggested a visual processing problem in the early stages of reading. The fourth case had a category-specific naming deficit after posterior thalamic lesion. Taken together, the latter two cases indicate that the nature of language functions in more posterior regions of the dominant thalamus depends upon the cortical connectivity of the thalamic region. Together, findings from the four cases suggest that thalamic nuclei and systems are involved in multiple processes which directly or indirectly support cortical language functions. Copyright 1999 Academic Press.

Subspecialization in the human posterior medial cortex

PubMed Central

Bzdok, Danilo; Heeger, Adrian; Langner, Robert; Laird, Angela R.; Fox, Peter T.; Palomero-Gallagher, Nicola; Vogt, Brent A.; Zilles, Karl; Eickhoff, Simon B.

2014-01-01

The posterior medial cortex (PMC) is particularly poorly understood. Its neural activity changes have been related to highly disparate mental processes. We therefore investigated PMC properties with a data-driven exploratory approach. First, we subdivided the PMC by whole-brain coactivation profiles. Second, functional connectivity of the ensuing PMC regions was compared by task-constrained meta-analytic coactivation mapping (MACM) and task-unconstrained resting-state correlations (RSFC). Third, PMC regions were functionally described by forward/reverse functional inference. A precuneal cluster was mostly connected to the intraparietal sulcus, frontal eye fields, and right temporo-parietal junction; associated with attention and motor tasks. A ventral posterior cingulate cortex (PCC) cluster was mostly connected to the ventromedial prefrontal cortex and middle left inferior parietal cortex (IPC); associated with facial appraisal and language tasks. A dorsal PCC cluster was mostly connected to the dorsomedial prefrontal cortex, anterior/posterior IPC, posterior midcingulate cortex, and left dorsolateral prefrontal cortex; associated with delay discounting. A cluster in the retrosplenial cortex was mostly connected to the anterior thalamus and hippocampus. Furthermore, all PMC clusters were congruently coupled with the default mode network according to task-constrained but not task-unconstrained connectivity. We thus identified distinct regions in the PMC and characterized their neural networks and functional implications. PMID:25462801

[Anatomy and malformations of the posterior cranial fossa].

PubMed

Struffert, T

2016-11-01

Many important structures are located in the confined space within the posterior cranial fossa. This article describes the main aspects of the anatomy. As a uniform classification of malformations of the posterior cranial fossa does not exist the main syndromes, such as Chiari malformations, zerebellar hypoplasia and dysplasia are discussed separately.

SURGICAL REMOVAL OF DENSE POSTERIOR CAPSULE OPACIFICATION AND VITREOUS FLOATERS IN ADULTS BY POSTERIOR CONTINUOUS CURVILINEAR CAPSULORHEXIS THROUGH THE PARS PLANA AND 23-GAUGE VITRECTOMY.

PubMed

Lin, Jijian; Su, Zhitao; Huang, Xiaodan; Ji, Xian; Yao, Ke

2016-11-01

To evaluate the safety and efficacy of posterior continuous curvilinear capsulorhexis through the pars plana and 23-gauge vitrectomy in surgical management of dense posterior capsule opacification and vitreous floaters. Fifteen pseudophakic eyes of 15 patients with dense posterior capsule opacification and vitreous floaters between September 2012 and June 2014 were included; after vitrectomy, posterior continuous curvilinear capsulorhexis through the pars plana was performed. Data were collected, including baseline preoperative characteristics, postoperative outcomes, complications, and a modified quality-of-life survey that patients completed. No intraoperative or postoperative complications were encountered in any of the 15 cases. Mean Snellen best-corrected visual acuity was 20/250 preoperatively and improved to 20/32 postoperatively (P < 0.001). All patients showed normal intraocular pressure 7 days after the procedure. The mean overall corneal endothelial cell loss at postoperative Month 3 was 1.2%. Approximately 80% of the patients had no complaint of vitreous floaters after the procedure. Except for 1 patient (7%) diagnosed with age-related macular degeneration, the rest of the patients (93%) were satisfied with the procedure and would recommend it to friends with dense posterior capsule opacification and vitreous floaters. Posterior continuous curvilinear capsulorhexis through the pars plana combined with 23-gauge vitrectomy may be used to remove dense posterior capsule opacification and vitreous floaters in pseudophakic eyes.

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.

Posterior Corneal Characteristics of Cataract Patients with High Myopia

PubMed Central

Jing, Qinghe; Tang, Yating; Qian, Dongjin; Lu, Yi; Jiang, Yongxiang

2016-01-01

Purpose To evaluate the characteristics of the posterior corneal surface in patients with high myopia before cataract surgery. Methods We performed a cross-sectional study at the Eye and ENT Hospital of Fudan University, Shanghai, China. Corneal astigmatism and axial length were measured with a rotating Scheimpflug camera (Pentacam) and partial coherence interferometry (IOLMaster) in a high-myopia study group of 167 eyes (axial length ≥ 26 mm) and a control group of 150 eyes (axial length > 20 mm and < 25 mm). Results Total corneal astigmatism and anterior corneal astigmatism values were higher in the high-myopia group than in the control group. There was no significant difference in posterior corneal astigmatism between the high-myopia study group and the control group. In the study group, the mean posterior corneal astigmatism (range 0 – −0.9 diopters) was –0.29 diopters (D) ± 0.17 standard deviations (SD). The steep corneal meridian was aligned vertically (60°–120°) in 87.43% of eyes for the posterior corneal surface, and did not change with increasing age. There was a significant correlation (r = 0.235, p = 0.002) between posterior corneal astigmatism and anterior corneal astigmatism, especially when the anterior corneal surface showed with-the-rule (WTR) astigmatism (r = 0.452, p = 0.000). There was a weak negative correlation between posterior corneal astigmatism and age (r = –0.15, p = 0.053) in the high-myopia group. Compared with total corneal astigmatism values, the anterior corneal measurements alone overestimated WTR astigmatism by a mean of 0.27 ± 0.18 D in 68.75% of eyes, underestimated against-the-rule (ATR) astigmatism by a mean of 0.41 ± 0.28 D in 88.89% of eyes, and underestimated oblique astigmatism by a mean of 0.24 ± 0.13 D in 63.64% of eyes. Conclusions Posterior corneal astigmatism decreased with age and remained as ATR astigmatism in most cases of high myopia. There was a significant correlation between posterior corneal

Posterior Corneal Characteristics of Cataract Patients with High Myopia.

PubMed

Jing, Qinghe; Tang, Yating; Qian, Dongjin; Lu, Yi; Jiang, Yongxiang

2016-01-01

To evaluate the characteristics of the posterior corneal surface in patients with high myopia before cataract surgery. We performed a cross-sectional study at the Eye and ENT Hospital of Fudan University, Shanghai, China. Corneal astigmatism and axial length were measured with a rotating Scheimpflug camera (Pentacam) and partial coherence interferometry (IOLMaster) in a high-myopia study group of 167 eyes (axial length ≥ 26 mm) and a control group of 150 eyes (axial length > 20 mm and < 25 mm). Total corneal astigmatism and anterior corneal astigmatism values were higher in the high-myopia group than in the control group. There was no significant difference in posterior corneal astigmatism between the high-myopia study group and the control group. In the study group, the mean posterior corneal astigmatism (range 0 - -0.9 diopters) was -0.29 diopters (D) ± 0.17 standard deviations (SD). The steep corneal meridian was aligned vertically (60°-120°) in 87.43% of eyes for the posterior corneal surface, and did not change with increasing age. There was a significant correlation (r = 0.235, p = 0.002) between posterior corneal astigmatism and anterior corneal astigmatism, especially when the anterior corneal surface showed with-the-rule (WTR) astigmatism (r = 0.452, p = 0.000). There was a weak negative correlation between posterior corneal astigmatism and age (r = -0.15, p = 0.053) in the high-myopia group. Compared with total corneal astigmatism values, the anterior corneal measurements alone overestimated WTR astigmatism by a mean of 0.27 ± 0.18 D in 68.75% of eyes, underestimated against-the-rule (ATR) astigmatism by a mean of 0.41 ± 0.28 D in 88.89% of eyes, and underestimated oblique astigmatism by a mean of 0.24 ± 0.13 D in 63.64% of eyes. Posterior corneal astigmatism decreased with age and remained as ATR astigmatism in most cases of high myopia. There was a significant correlation between posterior corneal astigmatism and anterior corneal astigmatism

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

[Posterior polymorphous dystrophy, case report and literature review].

PubMed

Mendoza-Adam, G; Hernandez-Camarena, J C; Valdez-García, J E

2015-09-01

Posterior Polymorphous Dystrophy (DPP) is a rare posterior corneal dystrophy that is genetically transmitted as autosomal dominant. Corneal structures affected in this dystrophy are Descemet membrane and the endothelium. A case is presented on a 47 years old woman with no relevant history, with typical findings of DPP (vesicular and band lesions at the endothelium and posterior Descemet). To our knowledge there are no reported cases of DPP in Latin-American patients in the literature. The clinical manifestations in our patient were found to be very similar to the cases reported in other populations. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Wnt signaling maintains the notochord fate for progenitor cells and supports the posterior extension of the notochord.

PubMed

Ukita, Kanako; Hirahara, Shino; Oshima, Naoko; Imuta, Yu; Yoshimoto, Aki; Jang, Chuan-Wei; Oginuma, Masayuki; Saga, Yumiko; Behringer, Richard R; Kondoh, Hisato; Sasaki, Hiroshi

2009-10-01

The notochord develops from notochord progenitor cells (NPCs) and functions as a major signaling center to regulate trunk and tail development. NPCs are initially specified in the node by Wnt and Nodal signals at the gastrula stage. However, the underlying mechanism that maintains the NPCs throughout embryogenesis to contribute to the posterior extension of the notochord remains unclear. Here, we demonstrate that Wnt signaling in the NPCs is essential for posterior extension of the notochord. Genetic labeling revealed that the Noto-expressing cells in the ventral node contribute the NPCs that reside in the tail bud. Robust Wnt signaling in the NPCs was observed during posterior notochord extension. Genetic attenuation of the Wnt signal via notochord-specific beta-catenin gene ablation resulted in posterior truncation of the notochord. In the NPCs of such mutant embryos, the expression of notochord-specific genes was down-regulated, and an endodermal marker, E-cadherin, was observed. No significant alteration of cell proliferation or apoptosis of the NPCs was detected. Taken together, our data indicate that the NPCs are derived from Noto-positive node cells, and are not fully committed to a notochordal fate. Sustained Wnt signaling is required to maintain the NPCs' notochordal fate.

The mirror mechanism in the parietal lobe.

PubMed

Rizzolatti, Giacomo; Rozzi, Stefano

2018-01-01

The mirror mechanism is a basic mechanism that transforms sensory representations of others' actions into motor representations of the same actions in the brain of the observer. The mirror mechanism plays an important role in understanding actions of others. In the present chapter we discuss first the basic organization of the posterior parietal lobe in the monkey, stressing that it is best characterized as a motor scaffold, on the top of which sensory information is organized. We then describe the location of the mirror mechanism in the posterior parietal cortex of the monkey, and its functional role in areas PFG, and anterior, ventral, and lateral intraparietal areas. We will then present evidence that a similar functional organization is present in humans. We will conclude by discussing the role of the mirror mechanism in the recognition of action performed with tools. Copyright © 2018 Elsevier B.V. All rights reserved.

Complex traumatic posterior urethral strictures.

PubMed

Turner-Warwick, R

1976-01-01

A distinction between simple and complex posterior urethral strictures is proposed. The development of a complex stricture, requiring an extensive transpubic repair, must be regarded as a less than admirable result of the initial treatment, even if it is occasionally inevitable. However, it is particularly important that our endeavors to improve the end result of the relatively rare severe urethral injuries should not result in over-management of the relatively minor injuries, since this could increase the stricture potential of many. Therefore, we must keep our over-all concepts of the initial management of urethral injuries under careful review. Posterior urethroplasty should be regarded as a specialist procedure. It can be made to appear beguilingly simple but it cannot be recommended for occasional or general use. Even the relatively simple free patch graft technique is inadvisable for use in the sphincter area for surgeons who do not have considerable experience of it in the relatively forgiving bulbourethral area. The results of repair of posterior urethral strictures, even the complex ones, by anastomotic procedures can be excellent but real competence depends upon a particular aptitude of the surgeon for the minutiae of reconstructive techniques, appropriate training in a specializing department, a real ongoing numerical experience and special instrumentation with facilities for detailed urodynamic evaluation of this sphincter active area of the urethra.

Progressive Posterior Lenticonus in a Patient with Alport Syndrome

PubMed Central

Al-Mahmood, Ammar M.; Al-Swailem, Samar A.; Al-Khalaf, Abdulrahman; Al-Binali, Ghada Y.

2010-01-01

We report a rare case of Alport syndrome with progressive posterior lenticonus. A 24-year-old male presented to our tertiary eye care center with history of poor vision. At initial presentation, the patient had bilateral anterior lenticonus, posterior subcapsular cataract, and renal failure. The patient was diagnosed with Alport syndrome based on a positive family history of the disease and clinical findings. Further examination revealed progressive posterior lenticonus that was not present initially. The presence of such finding is important because it influences the surgical approach to avoid complications during cataract surgery. PMID:21180444

A high-resolution 3D ultrasonic system for rapid evaluation of the anterior and posterior segment.

PubMed

Peyman, Gholam A; Ingram, Charles P; Montilla, Leonardo G; Witte, Russell S

2012-01-01

Traditional ultrasound imaging systems for ophthalmology employ slow, mechanical scanning of a single-element ultrasound transducer. The goal was to demonstrate rapid examination of the anterior and posterior segment with a three-dimensional (3D) commercial ultrasound system incorporating high-resolution linear probe arrays. The 3D images of the porcine eye were generated in approximately 10 seconds by scanning one of two commercial linear arrays (25- and 50-MHz). Healthy enucleated pig eyes were compared with those with induced injury or placement of a foreign material (eg, metal). Rapid, volumetric imaging was also demonstrated in one human eye in vivo. The 50-MHz probe provided exquisite volumetric images of the anterior segment at a depth up to 15 mm and axial resolution of 30 μm. The 25-MHz probe provided a larger field of view (lateral X depth: 20 × 30 mm), sufficient for capturing the entire anterior and posterior segments of the pig eye, at a resolution of 60 μm. A 50-MHz scan through the human eyelid illustrated detailed structures of the Meibomian glands, cilia, cornea, and anterior segment back to the posterior capsule. The 3D system with its high-frequency ultrasound arrays, fast data acquisition, and volume rendering capability shows promise for investigating anterior and posterior structures of the eye. Copyright 2012, SLACK Incorporated.

Rocket launcher: A novel reduction technique for posterior hip dislocations and review of current literature.

PubMed

Dan, Michael; Phillips, Alfred; Simonian, Marcus; Flannagan, Scott

2015-06-01

We provide a review of literature on reduction techniques for posterior hip dislocations and present our experience with a novel technique for the reduction of acute posterior hip dislocations in the ED, 'the rocket launcher' technique. We present our results with six patients with prosthetic posterior hip dislocation treated in our rural ED. We recorded patient demographics. The technique involves placing the patient's knee over the shoulder, and holding the lower leg like a 'Rocket Launcher' allow the physician's shoulder to work as a fulcrum, in an ergonomically friendly manner for the reducer. We used Fisher's t-test for cohort analysis between reduction techniques. Of our patients, the mean age was 74 years (range 66 to 85 years). We had a 83% success rate. The one patient who the 'rocket launcher' failed in, was a hemi-arthroplasty patient who also failed all other closed techniques and needed open reduction. When compared with Allis (62% success rate), Whistler (60% success rate) and Captain Morgan (92% success rate) techniques, there was no statistically significant difference in the successfulness of the reduction techniques. There were no neurovascular or periprosthetic complications. We have described a reduction technique for posterior hip dislocations. Placing the patient's knee over the shoulder, and holding the lower leg like a 'Rocket Launcher' allow the physician's shoulder to work as a fulcrum, thus mechanically and ergonomically superior to standard techniques. © 2015 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Tuberothalamic artery infarction following coil embolization of a ruptured posterior communicating artery aneurysm belonging to a transitional type posterior cerebral artery. A case report.

PubMed

Lee, Kyeong Duk; Kwon, Soon Chan; Muniandy, Sarawana; Park, Eun Suk; Sim, Hong Bo; Lyo, In Uk

2013-09-01

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.

Spontaneous regression of posterior epidural migrated lumbar disc fragments: case series.

PubMed

Tarukado, Kiyoshi; Ikuta, Ko; Fukutoku, Yoshiaki; Tono, Osamu; Doi, Toshio

2015-06-01

Posterior epidural migrated lumbar disc fragments is an extremely rare disorder. Surgical treatment was performed in all reported cases. To the best of our knowledge, there are no reported cases of the use of conservative treatment for posterior epidural migrated lumbar disc fragments. To report the possibility of a spontaneous regression of posterior epidural migrated lumbar disc fragments. Case series. Four patients with posterior epidural migrated lumbar disc fragments were treated at Karatsu Red Cross Hospital between April 2008 and August 2010. Spontaneous regression of the posterior epidural migrated lumbar disc fragments with relief of symptoms was observed on magnetic resonance imaging (MRI) in three cases. Another patient underwent surgical treatment. The present and previously reported cases of posterior epidural migrated lumbar disc fragments were analyzed with respect to patient age, imaging features on MRI, the level of the lesion, clinical symptoms, treatment, and outcomes. Conservative treatment was successful, and spontaneous lesion regression was seen on MRI with symptom relief in three cases. Although posterior epidural migrated lumbar disc fragment cases are generally treated surgically, the condition can regress spontaneously over time, as do sequestrated disc fragments. Spontaneous regression of lumbar disc herniations is a widely accepted observation at present. Posterior epidural migrated lumbar disc fragments fall under the sequestrated type of disc herniation. In fact, the course of treatment for posterior epidural migrated lumbar disc fragments should be determined based on the symptoms and examination findings, as in cases of ordinary herniation. However, providing early surgical treatment is important if the patient has acute cauda equina syndrome or the neurologic symptoms worsen over time. Copyright © 2015 Elsevier Inc. All rights reserved.

Gait adaptations in patients with chronic posterior instability of the knee.

PubMed

Hooper, D M; Morrissey, M C; Crookenden, R; Ireland, J; Beacon, J P

2002-03-01

A retrospective analysis was performed to assess gait in individuals with a long history of posterior knee instability. Descriptive study. There are few studies in the literature concerning evaluation of the biomechanics of the knee in patients with knee posterior instability. Nine individuals with posterior knee instability and a matched control group of uninjured subjects were tested in regards to knee kinematics and kinetics while walking and ascending and descending stairs. The mean follow up time for the individuals with posterior instability was 11.1 years. Individual satisfaction with the knee was measured by having participants complete the Flandry (also known as Hughston Clinic) self-assessment questionnaire. It was found that patients with knee posterior instability who indicated a higher level of satisfaction on the Flandry score walked in a manner that demonstrated greater peak knee extensor torque during stance phase, while less satisfied patients with knee posterior instability demonstrated lower peak knee extensor torque. There was a significant correlation between the self-assessment score and the peak knee extensor torque during level walking (P=0.003). During stair ascent and descent, patients with posterior instability averaged lower knee extensor torque and power than the control subjects, but those differences were only statistically significant in power while descending stairs (P=0.048). Individuals with chronic knee posterior instability modify their gait, and the adaptation can be predicted based upon the individuals self-assessment of their knee using the Flandry questionnaire. These data suggest that gait retraining may be a valuable addition to the traditional muscle strengthening programs, which are commonly used during conservative management of knee posterior instability.

Paraspinal muscle impingement causing acute Brown-Sequard syndrome after posterior cervical decompression.

PubMed

Jost, Patrick W; Marawar, Satyajit; O'Leary, Patrick F

2010-04-01

A case report. To present a previously unreported cause of neurologic compromise after cervical spine surgery. Several different causes of postoperative neurologic deficit have been reported in the literature. The authors present a case of acute postoperative paralysis after posterior cervical decompression by a mechanism that has not yet been reported in the literature. A 54-year-old muscular, short-statured man underwent posterior cervical laminectomy from C3-C5 without instrumentation and left C5 foraminotomy. Within hours of leaving the operating room, he began to develop postoperative neurologic deficits in his extremities, which progressed to a classic Brown-Sequard syndrome. Magnetic resonance imaging revealed regional kyphosis and large swollen paraspinal muscles impinging on the spinal cord without epidural hematoma. Emergent operative re-exploration confirmed these findings; large, swollen paraspinal muscles, a functioning drain, and no hematoma were found. The patient was treated with immediate corticosteroids at the time of initial diagnosis, and emergent re-exploration and debulking of the paraspinal muscles. The patient had complete recovery of neurologic function to his preoperative baseline after the second procedure but required a third procedure in which anterior discectomy and fusion at C4-C5 was performed, which led to improvement of his preoperative symptoms. When performing posterior cervical decompression, surgeons must be aware of the potential for loss of normal lordosis and anterior displacement of paraspinal muscles against the spinal cord, especially in muscular patients.

Effect of partial meniscectomy at the medial posterior horn on tibiofemoral contact mechanics and meniscal hoop strains in human knees.

PubMed

Seitz, Andreas Martin; Lubomierski, Anja; Friemert, Benedikt; Ignatius, Anita; Dürselen, Lutz

2012-06-01

We examined the influence of partial meniscectomy of 10 mm width on 10 human cadaveric knee joints, as it is performed during the treatment of radial tears in the posterior horn of the medial meniscus, on maximum contact pressure, contact area (CA), and meniscal hoop strain in the lateral and medial knee compartments. In case of 0° and 30° flexion angle, 20% and 50% partial meniscectomy did not influence maximum contact pressure and area. Only in case of 60° knee flexion, 50% partial resection increased medial maximum contact pressure and decreased the medial CA statistically significant. However, 100% partial resection increased maximum contact pressure and decreased CA significantly in the meniscectomized medial knee compartment in all tested knee positions. No significant differences were noted for meniscal hoop strain. From a biomechanical point of view, our in vitro study suggests that the medial joint compartment is not in danger of accelerated cartilage degeneration up to a resection limit of 20% meniscal depth and 10 mm width. Contact mechanics are likely to be more sensitive to partial meniscectomy at higher flexion angles, which has to be further investigated. Copyright © 2011 Orthopaedic Research Society.

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.

Focal Choroidal Excavation in Best Vitelliform Macular Dystrophy: Case Report

PubMed Central

Esfahani, Mohammad Riazi; Esfahani, Hamid Riazi; Mahmoudi, Alireza; Johari, Mohammad Karim

2015-01-01

Focal choroidal excavation (FCE) was first reported as a choroidal posteriorly excavated zone without any scleral change. Choroidal excavation also divided into conforming and nonconforming type. Numerous reports demonstrated association between FCE and other disease such as choroidal neovascularization and central serous choroidoretinopathy. Here, we report a rare case of FCE in a patient with Best disease. The patient was diagnosed by spectoral domain optical coherence tomography (SD-OCT). To the best of our knowledge, our patient is the second report of choroidal excavation in Best vitelliform macular dystrophy. PMID:26155505

Unrecognized hemangiopericytoma of posterior cervical region with intracranial extension.

PubMed

Vilendecic, Milorad; Grahovac, Gordan; Lambasa, Smiljka; Jelec, Vjekoslav; Topic, Iva

2012-02-01

Hemangiopericytoma of the posterior cervical space and occipital bone is an uncommon lesion which should be considered in the differential diagnosis of a lumpy and highly vascular lesion of the posterior cervical space. We report the case of a 47-year-old woman who experienced sudden and painful occipital and posterior cervical swelling. She underwent a blind biopsy which was complicated by profuse bleeding. The palpable lesion was not properly diagnosed preoperatively, and the endocranial extension of the lesion was overlooked by her surgeon who performed a blind biopsy without adequate diagnostic imaging who inadvertently invaded the posterior cranial fossa during biopsy. We would like to emphasize the need for appropriate non-invasive diagnostic investigations before any biopsy of head and neck lesions that may extend deeply. Copyright © 2011 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Reversible posterior leucoencephalopathy syndrome in a peripartum patient.

PubMed

Prout, R E; Tuckey, J P; Giffen, N J

2007-01-01

We present the case of a multiparous parturient who developed hypertension associated with a severe headache in the immediate post-partum period. She subsequently suffered a generalised tonic clonic seizure on the fifth post-partum day. Following recovery of consciousness, she developed a left homonymous hemianopia. Apart from hypertension, headache and convulsion, she had no symptoms and no proteinuria or other biochemical or haematological changes associated with eclampsia. The magnetic resonance imaging findings were consistent with vasogenic oedema in the right posterior parieto-occipital white matter and these in turn are consistent with reversible posterior leucoencephalopathy syndrome. The differential diagnosis of convulsions in the post-partum period is discussed and the clinical and radiological features of reversible posterior leucoencephalopathy syndrome are described.

Posterior Vertebral Column Resection for Severe and Rigid Spinal Deformity Associated With Neurological Deficit After Implant Removal Following Posterior Instrumented Fusion: A Case Report and Literature Review.

PubMed

Tao, Youping; Wu, Jigong; Ma, Huasong; Zhang, Lele; Shao, Shuilin; Si, Zebing; Gao, Bo; Ji, Yong; Li, Haixia; Tao, Feifei

2015-07-01

Case report. To investigate the safety and efficacy of posterior vertebral column resection for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion. Loss of correction after implant removal in patients with posterior instrumented fusion has been previously reported. However, to our knowledge, posterior vertebral column resection (PVCR) for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion has not been reported. An 18-year-old female with severe and rigid spinal deformity associated with neurological deficit was classified as Frankel C, according to the Frankel grading system. She underwent posterior spinal fusion with pedicle screw fixation at 16 years, and her implants were removed after 1 year due to back pain. Seven months after removal of the implants, she began to experience weakness in her lower limbs but did not seek any treatment. She was unable to stand and had to use a wheelchair. The patient successfully underwent PVCR and posterior reinstrumentation. Within 3 months, her neurological status improved to Frankel E. The patient had no neurological deterioration and infections. There was no instrumentation failure and loosening correction at the 32 months follow-up. Our results suggest that PVCR and pedicle screw fixation is a safe and efficacious option for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion. N/A.

Changing Trends in Surgery for Retinal Detachment in Korea

PubMed Central

Cho, Ga Eun; Kim, Seong Wook

2014-01-01

Purpose To analyze trends in rhegmatogenous retinal detachment (RRD) surgery among the members of the Korean Retina Society from 2001 to 2013. Methods In 2013, surveys were conducted by email and post to investigate the current practice patterns regarding RRD treatment. Questions included how surgeons would manage six cases of hypothetical RRD. Results were compared to those reported in 2001. Results A total of 133 members (60.7%) in 2013 and 46 members(79.3%) in 2001 responded to the survey. Preference for pneumatic retinopexy has decreased in uncomplicated primary RRD (p = 0.004). More respondents in 2013 selected vitrectomy as the primary procedure when mild vitreous hemorrhage (p = 0.001), myopia (p = 0.044) and history of successful scleral buckling on the fellow eye (p = 0.044) were added to the primary scenario. Vitrectomy was over twice as popular in cases of pseudophakic, macula-off RRD with posterior capsular opacity (p = 0.001). Conclusions For RRD with myopia, pseudophakia and media opacity, surgical interventions over the last decade have drastically shifted from scleral buckling and pneumatic retinopexy to vitrectomy. PMID:25435747

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.

Absence of posterior tricuspid valve leaflet and valve reconstruction

PubMed Central

Komoda, Takeshi; Stamm, Christof; Fleck, Eckart; Hetzer, Roland

2012-01-01

We report a rare case of the absence of a posterior tricuspid valve leaflet. A male patient, aged 46, suffering from severe tricuspid valve regurgitation (TR) of unknown aetiology and atrial septal aneurysm was referred to our hospital for surgery. On surgical inspection, the posterior tricuspid valve leaflet and its subvalvular apparatus were completely absent and only the valve annulus was seen in the corresponding position. The anterior and septal leaflets were normal. We successfully reconstructed the tricuspid valve as follows: the head of an anterior papillary muscle was approximated to the ventricular septum (Sebening stitch). After the approximation of the centre of the tricuspid annulus of the anterior leaflet to the tricuspid annulus on the opposite side, a sizer of 29 mm in diameter was easily passed through the anterior orifice. The posterior orifice was closed with running sutures (posterior annulorrhaphy after Hetzer). Before these procedures, we attempted to reconstruct the tricuspid valve with a posterior annulorrhaphy alone; however, valve competence was insufficient. A Sebening stitch was necessary to improve the valve competence. Echocardiography showed TR grade 1 at the patient's discharge from hospital and TR grade 1 to 2 at the follow-up, 10 months after the operation. PMID:22419794

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.

Mean Posterior Corneal Power and Astigmatism in Normal Versus Keratoconic Eyes.

PubMed

Feizi, Sepehr; Delfazayebaher, Siamak; Javadi, Mohammad Ali; Karimian, Farid; Ownagh, Vahid; Sadeghpour, Fatemeh

2018-01-01

To compare mean posterior corneal power and astigmatism in normal versus keratoconus affected eyes and determine the optimal cut-off points to maximize sensitivity and specificity in discriminating keratoconus from normal corneas. A total of 204 normal eyes and 142 keratoconus affected eyes were enrolled in this prospective comparative study. Mean posterior corneal power and astigmatism were measured using a dual Scheimpflug camera. Correlation coefficients were calculated to assess the relationship between the magnitudes of keratometric and posterior corneal astigmatism in the study groups. Receiver operating characteristic curves were used to compare the sensitivity and specificity of the measured parameters and to identify the optimal cut-off points for discriminating keratoconus from normal corneas. The mean posterior corneal power was -6.29 ± 0.20 D in the normal group and -7.77 ± 0.87 D in the keratoconus group ( P < 0.001). The mean magnitudes of the posterior corneal astigmatisms were -0.32 ± 0.15 D and -0.94 ± 0.39 D in the normal and keratoconus groups, respectively ( P < 0.001). Significant correlations were found between the magnitudes of keratometric and posterior corneal astigmatism in the normal (r=-0.76, P < 0.001) and keratoconus (r=-0.72, P < 0.001) groups. The mean posterior corneal power and astigmatism were highly reliable characteristics that distinguished keratoconus from normal corneas (area under the curve, 0.99 and 0.95, respectively). The optimal cut-off points of mean posterior corneal power and astigmatism were -6.70 D and -0.54 D, respectively. Mean posterior corneal power and astigmatism measured using a Galilei analyzer camera might have potential in diagnosing keratoconus. The cut-off points provided can be used for keratoconus screening.

Biomechanical demands on posterior fusion instrumentation during lordosis restoration procedures.

PubMed

Kuo, Calvin C; Martin, Audrey; Telles, Connor; Leasure, Jeremi; Iezza, Alex; Ames, Christopher; Kondrashov, Dimitriy

2016-09-01

OBJECTIVE The goal of this study was to investigate the forces placed on posterior fusion instrumentation by 3 commonly used intraoperative techniques to restore lumbar lordosis: 1) cantilever bending; 2) in situ bending; and 3) compression and/or distraction of screws along posterior fusion rods. METHODS Five cadaveric torsos were instrumented with pedicle screws at the L1-5 levels. Specimens underwent each of the 3 lordosis restoration procedures. The pedicle screw pullout force was monitored in real time via strain gauges that were mounted unilaterally at each level. The degree of correction was noted through fluoroscopic imaging. The peak loads experienced on the screws during surgery, total demand on instrumentation, and resting loads after corrective maneuvers were measured. RESULTS A mean overall lordotic correction of 10.9 ± 4.7° was achieved. No statistically significant difference in lordotic correction was observed between restoration procedures. In situ bending imparted the largest loads intraoperatively with an average of 1060 ± 599.9 N, followed by compression/distraction (971 ± 534.1 N) and cantilever bending (705 ± 413.0 N). In situ bending produced the largest total demand and postoperative loads at L-1 (1879 ± 1064.1 and 487 ± 118.8 N, respectively), which were statistically higher than cantilever bending and compression/distraction (786 ± 272.1 and 138 ± 99.2 N, respectively). CONCLUSIONS In situ bending resulted in the highest mechanical demand on posterior lumbar instrumentation, as well as the largest postoperative loads at L-1. These results suggest that the forces generated with in situ bending indicate a greater chance of intraoperative instrumentation failure and postoperative proximal pedicle screw pullout when compared with cantilever bending and/or compression/distraction options. The results are aimed at optimizing correction and fusion strategies in lordosis restoration cases.

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.

Treatment of posterior cruciate ligament tibial avulsion by a minimally-invasive open posterior approach.

PubMed

Abdallah, Ahmed Abdelbadie; Arafa, Mohammed S

2017-07-01

To assess the surgical technique and report the outcomes following fixation of PCL bony avulsions through mini-invasive posterior knee approach as described by Burks and Schaffer. From June 2012 to July 2015, 27 patients enrolled in the study (21 males and 6 females). Fixation of tibial PCL avulsion fractures was done with one or two cannulated screws, or sutures through Burks and Schaffer's approach. The mean interval before surgery was 16days (1-70) .Patients was followed up for an average of 51 weeks. The outcome measures evaluated at final follow-up were (1) clinical stability as assessed by posterior drawer test, (2) radiologic union, (3) functional assessment by Lysholm score, and (4) gastrocnemius muscle strength as a measure of morbidity. Average operative time was 43min. Improvement of both subjective Lysholm score (mean 93) and objective stability testing by posterior drawer test (returns to normal in 81.1% of patients) at the final follow-up. Good radiographic union at average of 5.6 weeks. No morbidity of the gastrocnemius with few complications. The approach was fast and safe with excellent visualization. It allows surgeons to address other injuries in the same setting. It can be considered as a minimally-invasive open surgery without surgery-related morbidity. It is a reproducible technique that can be done at any trauma centre by surgeons with average experience. The subjective and objective results of the technique are excellent and comparable to the arthroscopic procedures that needs more specific centres with well-trained surgeons. Copyright © 2017 Elsevier Ltd. All rights reserved.

Posterior propriety for hierarchical models with log-likelihoods that have norm bounds

DOE PAGES

Michalak, Sarah E.; Morris, Carl N.

2015-07-17

Statisticians often use improper priors to express ignorance or to provide good frequency properties, requiring that posterior propriety be verified. Our paper addresses generalized linear mixed models, GLMMs, when Level I parameters have Normal distributions, with many commonly-used hyperpriors. It provides easy-to-verify sufficient posterior propriety conditions based on dimensions, matrix ranks, and exponentiated norm bounds, ENBs, for the Level I likelihood. Since many familiar likelihoods have ENBs, which is often verifiable via log-concavity and MLE finiteness, our novel use of ENBs permits unification of posterior propriety results and posterior MGF/moment results for many useful Level I distributions, including those commonlymore » used with multilevel generalized linear models, e.g., GLMMs and hierarchical generalized linear models, HGLMs. Furthermore, those who need to verify existence of posterior distributions or of posterior MGFs/moments for a multilevel generalized linear model given a proper or improper multivariate F prior as in Section 1 should find the required results in Sections 1 and 2 and Theorem 3 (GLMMs), Theorem 4 (HGLMs), or Theorem 5 (posterior MGFs/moments).« less

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.

Descemet membrane endothelial keratoplasty in cases with existing scleral-sutured and iris-sutured intraocular lenses

PubMed Central

2014-01-01

Background To report two cases of Descemet Membrane Endothelial Keratoplasty (DMEK) in patients with existing scleral-fixated and iris-fixated intraocular lenses (sf-IOL and if-IOL, respectively). Case presentation DMEK procedures were performed on a 49-year-old woman with a pre-existing sf-IOL (case 1) and a 69-year-old woman with a pre-existing if-IOL (case 2) in order to treat secondary corneal edema due to pseudophakic bullous keratopathy. Visual acuity, refractive error, intraocular pressure, slit lamp examination, pachymetry measurements and endothelial cell density (ECD) were considered and repeated during follow-ups. Both cases had no intraoperative complications. At postoperative day 1 graft centration and complete attachment were noted. The IOL positions were unchanged in comparison to their preoperative positions. In case 1, visual acuity improved from 1/15 at 1 meter preoperative to 20/200 within one week and to 20/63 within 12 weeks of follow up. In case 2, visual acuity improved from counting fingers at 1 meter preoperative to 20/200 within one week and to 20/100 within 12 weeks of follow-up. In case 2 a partial graft dislocation was observed at postoperative day twenty. Complete graft re-apposition was achieved by rebubbling procedure performed with intracameral air injection. Conclusions DMEK surgery in the treatment of pseudophakic bullous keratopathy in the presence of sf-IOL and if-IOL can successfully be performed. These eyes are at increased risk of IOL dislocation into the vitreous cavity during DMEK surgery. PMID:24443809

The new transperineal-prerectal approach in posterior urethroplasty.

PubMed

Austoni, Edoardo; Guarneri, Andrea; Colombo, Fulvio; Palminteri, Enzo

2005-06-01

A new posterior urethroplasty is suggested for patients with pelvic fracture urethral distraction defect (PFUDD). 12 men, with PFUDD were treated with an anastomotic urethroplasty, using a transperineal-prerectal approach. All patients had a suprapubic tube in place and were impotent after pelvic trauma. The goal of this approach was to facilitate an extensive removal of the scar tissues around the prostatic apex to promote successful bulbo-prostatic anastomosis. No patients had intraoperative, perioperative or postoperative complications. Urinary incontinence or rectourethral fistula was never observed. In 11 patients the postoperative mean peak flow was 20 ml/sec. The recurrence of the stricture occurred in 1 patient. The transperineal-prerectal approach to the posterior urethra facilitated a free tension posterior end-to-end anastomosis, as an alternative to the transpubic anastomotic procedure.

[The clinical effect and disquisition of anterior cervical approach surgery with posterior longitudinal ligament hook pliers and posterior longitudinal ligament nip pliers].

PubMed

Kuang, Ling-hao; Xu, Dong; Sun, Ya-wei; Cong, Jie; Tian, Ji-wei; Wang, Lei

2010-09-21

To study the clinical effect of anterior cervical approach surgery to removal posterior longitudinal ligament (PLL) with posterior longitudinal ligament hook pliers and posterior longitudinal ligament nip pliers. To retrospectively analyzed anterior cervical approach surgery treatment 73 patients who were cervical spondylosis myelopathy. All patients removal PLL with self-make instrument, According to JOA grade to evaluate effect of operations. Full patients removal PLL were in succeed, in shape of extradural has renew, the JOA grade were increase, (12.8 ± 3.2) vs (8.3 ± 1.9). Removal PLL were increase effect of downright decompress in anterior cervical approach surgery, Operations become safety agile and reduce the complications with self-make instrument.

The effect of proximal tibial slope on dynamic stability testing of the posterior cruciate ligament- and posterolateral corner-deficient knee.

PubMed

Petrigliano, Frank A; Suero, Eduardo M; Voos, James E; Pearle, Andrew D; Allen, Answorth A

2012-06-01

Proximal tibial slope has been shown to influence anteroposterior translation and tibial resting point in the posterior cruciate ligament (PCL)-deficient knee. The effect of proximal tibial slope on rotational stability of the knee is unknown. Change in proximal tibial slope produced via osteotomy can influence both static translation and dynamic rotational kinematics in the PCL/posterolateral corner (PLC)-deficient knee. Controlled laboratory study. Posterior drawer, dial, and mechanized reverse pivot-shift (RPS) tests were performed on hip-to-toe specimens and translation of the lateral and medial compartments measured utilizing navigation (n = 10). The PCL and structures of the PLC were then sectioned. Stability testing was repeated, and compartmental translation was recorded. A proximal tibial osteotomy in the sagittal plane was then performed achieving either +5° or -5° of tibial slope variation, after which stability testing was repeated (n = 10). Analysis was performed using 1-way analysis of variance (ANOVA; α = .05). Combined sectioning of the PCL and PLC structures resulted in a 10.5-mm increase in the posterior drawer, 15.5-mm increase in the dial test at 30°, 14.5-mm increase in the dial test at 90°, and 17.9-mm increase in the RPS (vs intact; P < .05). Increasing the posterior slope (high tibial osteotomy [HTO] +5°) in the PCL/PLC-deficient knee reduced medial compartment translation by 3.3 mm during posterior drawer (vs deficient; P < .05) but had no significant effect on the dial test at 30°, dial test at 90°, or RPS. Conversely, reversing the slope (HTO -5°) caused a 4.8-mm increase in medial compartment translation (vs deficient state; P < .05) during posterior drawer and an 8.6-mm increase in lateral compartment translation and 9.0-mm increase in medial compartment translation during RPS (vs deficient state; P < .05). Increasing posterior tibial slope diminished static posterior instability of the PCL/PLC-deficient knee as measured by the

Posterior epidural disc fragment masquerading as spinal tumor: Review of the literature.

PubMed

Park, Taejune; Lee, Ho Jun; Kim, Jae Seong; Nam, Kiyeun

2018-03-09

Posterior epidural lumbar disc fragment is infrequent because of anatomical barriers, and it is difficult to diagnose posterior epidural lumbar disc fragment because of its rare incidence and the ambiguity of radiologic evaluations. And it is difficult to differentiate it from other diseases such as spinal tumors. Differential diagnosis of posterior epidural lumbar disc fragment is clinically important because its diagnosis can affect treatment and prognosis. To investigate the incidence, anatomical concern, etiology, symptom, diagnostic tool, management and prognosis of posterior epidural lumbar disc fragment, we reviewed articles including case report. We performed a search of all clinical studies of posterior epidural lumbar disc fragment published to date. The following keywords were searched: Posterior epidural lumbar disc fragment, disc migration, posterior epidural disc, extradural migration, dorsal epidural migration, sequestrated disc, and disc fragment. We identified 40 patients of posterior epidural lumbar disc fragment from 28 studies. The most common presentation of posterior epidural lumbar disc fragment was sudden onset radiculopathy (70.0%), followed by cauda equina syndrome (27.5%). The most frequently used diagnostic modality was magnetic resonance imaging (MRI), conducted in 36 cases (90.0%), and followed by computed tomography in 14 cases (35.0%). After the imaging studies, the preoperative diagnoses were 45.0% masses, 20.0% lesions, and 12.5% tumors. Characteristic MRI findings in posterior epidural lumbar disc fragment are helpful for diagnosis; it typically displays low signals on T1-weighted images and high signals on T2-weighted images with respect to the parent disc. In addition, most of the disc fragments show peripheral rim enhancement on MRI with gadolinium administration. Electrodiagnostic testing is useful for verifying nerve damage. Surgical treatment was performed in all cases, and neurologic complications were observed in 12.5%. As

Thoracolumbar spinal tuberculosis with psoas abscesses treated by one-stage posterior transforaminal lumbar debridement, interbody fusion, posterior instrumentation, and postural drainage.

PubMed

Pang, Xiaoyang; Shen, Xiongjie; Wu, Ping; Luo, Chenke; Xu, Zhengquan; Wang, Xiyang

2013-06-01

Retrospective analysis of the clinical efficacy and feasibility of patients with thoracolumbar spinal tuberculosis with psoas abscesses treated by one-stage posterior transforaminal lumbar debridement, interbody fusion, posterior instrumentation, and postural drainage. A total of 18 patients with thoracolumbar tuberculosis (TB), between February 2007 and February 2011, underwent one-stage posterior transforaminal lumbar debridement, interbody fusion, posterior instrumentation, and postural drainage. And the clinical efficacy was evaluated based on surgery duration time, the blood loss, the postural drainage of time, neurological status that was recorded by American Spinal Injury Association (ASIA) Impairment Scale, the fate of bone graft fusion, kyphosis angle, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), which were collected at certain time. The average follow-up period was 34 months (range 18-48 months). 18 patients suffered from seriously neurological deficits pre-operatively, of which 16 patients returned to normal at final follow-up. The surgery duration time was 197 ± 37.9 min, and the blood loss was 815 ± 348.5 ml. The postural drainage of time was 7.2 ± 2.7 days. The psoas abscesses disappeared in all cases, within the time range of 6-9 months (mean 7.4 ± 1.2 months). All patients of the grafted bones were thoroughly fused, with a fusion time ranging from 4 to 12 months (mean 7.8 months). Kyphosis angle was 44.32 ± 7.26° on average pre-operative and returned to 11.72 ± 2.85° at 6 weeks after operation; kyphosis angle was 13.10 ± 2.39° at final follow-up. The values of ESR and CRP were significant declined at 6 weeks post-operative, and returned to normal levels at final follow-up. With standardized anti-TB chemotherapy, thoracolumbar spinal tuberculosis with psoas abscesses could be effectively treated by one-stage posterior transforaminal lumbar debridement, interbody fusion, posterior instrumentation, and postural drainage.

Treatment planning of implants in posterior quadrants.

PubMed

Jivraj, S; Chee, W

2006-07-08

Differences in anatomy and biomechanics make treatment of posterior quadrants with dental implants substantially different to that of anterior areas. Without implants, when posterior teeth were lost, treatment options included a long span fixed partial denture or a removable prosthesis, especially when no terminal abutment was available. Today, with the use of implants, options are available that allow preservation of unrestored teeth.(1) When teeth are missing, implant supported restorations can be considered the treatment of choice from the perspective of occlusal support, preservation of adjacent teeth and avoidance of a removable partial denture.

Bilateral posterior fracture-dislocation of the shoulder: Report of two cases

PubMed Central

Claro, Rui; Sousa, Ricardo; Massada, Marta; Ramos, Joaquim; Lourenço, José M.

2009-01-01

Bilateral posterior fracture-dislocation of the shoulder is a very rare injury. Almost 50% of bilateral posterior dislocations are due to a convulsive seizure, rising to 90% if the dislocations are associated with fractures. Electric shock accounts for less than 5% of bilateral posterior dislocations of the shoulder. A systematization of the clinical and radiological approach, followed by an early diagnosis and proper surgical treatment is essential. Authors report 2 cases of bilateral posterior fracture-dislocation of the shoulder, one caused by a convulsive seizure and the other by an electric shock. A review of literature and a treatment protocol are also presented. PMID:20661400

Shape change in the atlas with congenital midline non-union of its posterior arch: a morphometric geometric study.

PubMed

Ríos, Luis; Palancar, Carlos; Pastor, Francisco; Llidó, Susana; Sanchís-Gimeno, Juan Alberto; Bastir, Markus

2017-10-01

The congenital midline non-union of the posterior arch of the atlas is a developmental variant present at a frequency ranging from 0.7% to 3.9%. Most of the reported cases correspond to incidental findings during routine medical examination. In cases of posterior non-union, hypertrophy of the anterior arch and cortical bone thickening of the posterior arches have been observed and interpreted as adaptive responses of the atlas to increased mechanical stress. We sought to determine if the congenital non-union of the posterior arch results in a change in the shape of the atlas. This study is an analysis of the first cervical vertebrae from osteological collections through morphometric geometric techniques. A total of 21 vertebrae were scanned with a high-resolution three-dimensional scanner (Artec Space Spider, Artec Group, Luxembourg). To capture vertebral shape, 19 landmarks and 100 semilandmarks were placed on the vertebrae. Procrustes superimposition was applied to obtain size and shape data (MorphoJ 1.02; Klingenberg, 2011), which were analyzed through principal component analysis (PCA) and mean shape comparisons. The PCA resulted in two components explaining 22.32% and 18.8% of the total shape variance. The graphic plotting of both components indicates a clear shape difference between the control atlas and the atlas with posterior non-union. This observation was supported by statistically significant differences in mean shape comparisons between both types of vertebra (p<.0001). Changes in shape were observed in the superior and inferior articular facets, the transverse processes, and the neural canal between the control and non-union vertebrae. Non-union of the posterior arch of the atlas is associated with significant changes in the shape of the vertebra. Copyright © 2017 Elsevier Inc. All rights reserved.

[Buffering capacity of the vitreous body in aggressive posterior retinopathy of prematurity].

PubMed

Amkhanitskaia, L I; Sidorenko, E I; Nikolaeva, G V; Kuznetsova, Iu D

2014-01-01

To investigate the role of vitreous body changes in the pathogenesis of aggressive posterior retinopathy of prematurity. The study included 60 children with stage 4-5 retinopathy of prematurity demonstrating either classical or aggressive posterior form of progression. In all cases vitreous samples for laboratory testing were taken during surgery. The study showed that aggressive posterior retinopathy of prematurity is associated with more significant metabolic changes in comparison with classical form of the disease. The degree of biochemical imbalance of the vitreous appeared directly related to the stage of the disease, which was determined by the type and extent of retinal detachment. Volcano-shaped retinal detachment with intensive exudation within the posterior eye segment is considered the most severe variant of aggressive posterior retinopathy of prematurity. Aggressive posterior retinopathy of prematurity is characterized by substantial disturbance of metabolism of the vitreous body, which contributes to exudation and proliferation, thus aggravating the course of the disease and worsening the prognosis.

Bilateral anomalous origins of the posterior meningeal artery from the ascending pharyngeal arteries.

PubMed

Hsu, C Y; Sheu, J J; Huang, K M; Li, Y W

2001-06-01

We present a rare case of angiographically confirmed dural arteriovenous fistula supplied mainly by the posterior meningeal artery with bilateral anomalous origins from the bilateral ascending pharyngeal arteries. The bilaterality of the origins of the posterior meningeal artery is important in the angiographic diagnosis and management of a dural vascular malformation in the posterior fossa or the posterior part of the falx cerebri.

Recurrent hemorrhage in hemangioblastoma involving the posterior fossa: Case report

PubMed Central

Marvin, Eric; Akhter, Asad S.; Coppens, Jeroen R.

2017-01-01

Background: Hemangioblastomas (HGBs) are the most common primary intra-axial posterior fossa tumor in adults. Although spontaneous hemorrhage of these tumors is exceedingly rare, despite their vascular nature, we describe a case of recurrent hemorrhage with associated tonsillar herniation, and demonstrate that a surgical approach can provide a suitable outcome. Case Description: A 54-year-old female with von Hippel-Lindau (VHL) syndrome presented with acute loss of consciousness and Glasgow Coma Scale (GCS) was 4. Computed tomographic (CT) images demonstrated large volume subarachnoid hemorrhage of the posterior fossa with intraventricular extension and intraparenchymal hemorrhage involving the right cerebellar tonsil. Magnetic resonance imaging (MRI) displayed three lesions in the posterior fossa, two near the hemorrhage site. Patient underwent suboccipital craniectomy with a decent recovery followed by radiosurgery as she refused resection. A second hemorrhage occurred ultimately prompting surgical resection of the three posterior fossa lesions, with a reasonable postoperative course. Conclusion: Hemorrhage of HGBs of the posterior fossa can present in conjunction of tonsillar herniation. Re-hemorrhage appears to be likely if prior acute hemorrhage has occurred. A stepwise approach of surgical decompression and resection may provide the best outcome. PMID:28713626

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

Identification and transcriptional profile of multiple genes in the posterior kidney of Nile tilapia at 6h post bacterial infections

USDA-ARS?s Scientific Manuscript database

To understand the molecular mechanisms involved in response of Nile tilapia (Oreochromis niloticus) to bacterial infection, suppression subtractive cDNA hybridization technique was used to identify upregulated genes in the posterior kidney of Nile tilapia at 6h post infection with Aeromonas hydrophi...

Application of adipose-derived stem cells on scleral contact lens carrier in an animal model of severe acute alkaline burn.

PubMed

Espandar, Ladan; Caldwell, Delmar; Watson, Richard; Blanco-Mezquita, Tomas; Zhang, Shijia; Bunnell, Bruce

2014-07-01

To evaluate the therapeutic effect of human adipose-derived stem cells (hASCs) overlaid on a scleral contact lens (SCL) carrier in a rabbit model of ocular alkaline burn. After inducing alkaline burn in 11 New Zealand white rabbits, hASCs cultured on SCLs were placed on the right eye of 5 rabbits, SCLs without cells were used in 5, and no treatment was applied in 1 eye. Each eye was examined and photographed for corneal vascularization, opacities, and epithelial defect in week 1, 2, and 4 after surgery. After 1 month, rabbits were killed and the corneas were removed and cut in half for electron and light microscopy examination. Human adipose-derived stem cells were attached to SCL surface and confluent easily. Human adipose-derived stem cells on SCL eyes showed smaller epithelial defect, less corneal opacity, corneal neovascularization relative to SCL eyes. Both groups showed no symblepharon. However, the cornea in the untreated eye was melted in 2 weeks and developed severe symblepharon. Human adipose-derived stem cells on SCL can reduce inflammation and corneal haziness in severe ocular alkaline burn injury in rabbits.

Application of Adipose-Derived Stem Cells on Scleral Contact Lens Carrier in an Animal Model of Severe Acute Alkaline Burn

PubMed Central

Espandar, Ladan; Caldwell, Delmar; Watson, Richard; Blanco-Mezquita, Tomas; Zhang, Shijia; Bunnell, Bruce

2015-01-01

Purpose To evaluate the therapeutic effect of human adipose-derived stem cells (hASCs) overlaid on a scleral contact lens (SCL) carrier in a rabbit model of ocular alkaline burn. Materials and Methods After inducing alkaline burn in 11 New Zealand white rabbits, hASCs cultured on SCLs were placed on the right eye of 5 rabbits, SCLs without cells were used in 5, and no treatment was applied in 1 eye. Each eye was examined and photographed for corneal vascularization, opacities, and epithelial defect in week 1, 2, and 4 after surgery. After 1 month, rabbits were killed and the corneas were removed and cut in half for electron and light microscopy examination. Results Human adipose-derived stem cells were attached to SCL surface and confluent easily. Human adipose-derived stem cells on SCL eyes showed smaller epithelial defect, less corneal opacity, corneal neovascularization relative to SCL eyes. Both groups showed no symblepharon. However, the cornea in the untreated eye was melted in 2 weeks and developed severe symblepharon. Conclusion Human adipose-derived stem cells on SCL can reduce inflammation and corneal haziness in severe ocular alkaline burn injury in rabbits. PMID:24901976

3D Shape Perception in Posterior Cortical Atrophy: A Visual Neuroscience Perspective.

PubMed

Gillebert, Céline R; Schaeverbeke, Jolien; Bastin, Christine; Neyens, Veerle; Bruffaerts, Rose; De Weer, An-Sofie; Seghers, Alexandra; Sunaert, Stefan; Van Laere, Koen; Versijpt, Jan; Vandenbulcke, Mathieu; Salmon, Eric; Todd, James T; Orban, Guy A; Vandenberghe, Rik

2015-09-16

Posterior cortical atrophy (PCA) is a rare focal neurodegenerative syndrome characterized by progressive visuoperceptual and visuospatial deficits, most often due to atypical Alzheimer's disease (AD). We applied insights from basic visual neuroscience to analyze 3D shape perception in humans affected by PCA. Thirteen PCA patients and 30 matched healthy controls participated, together with two patient control groups with diffuse Lewy body dementia (DLBD) and an amnestic-dominant phenotype of AD, respectively. The hierarchical study design consisted of 3D shape processing for 4 cues (shading, motion, texture, and binocular disparity) with corresponding 2D and elementary feature extraction control conditions. PCA and DLBD exhibited severe 3D shape-processing deficits and AD to a lesser degree. In PCA, deficient 3D shape-from-shading was associated with volume loss in the right posterior inferior temporal cortex. This region coincided with a region of functional activation during 3D shape-from-shading in healthy controls. In PCA patients who performed the same fMRI paradigm, response amplitude during 3D shape-from-shading was reduced in this region. Gray matter volume in this region also correlated with 3D shape-from-shading in AD. 3D shape-from-disparity in PCA was associated with volume loss slightly more anteriorly in posterior inferior temporal cortex as well as in ventral premotor cortex. The findings in right posterior inferior temporal cortex and right premotor cortex are consistent with neurophysiologically based models of the functional anatomy of 3D shape processing. However, in DLBD, 3D shape deficits rely on mechanisms distinct from inferior temporal structural integrity. Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visuoperceptual dysfunction and most often an atypical presentation of Alzheimer's disease (AD) affecting the ventral and dorsal visual streams rather than the medial temporal system. We applied

3D Shape Perception in Posterior Cortical Atrophy: A Visual Neuroscience Perspective

PubMed Central

Gillebert, Céline R.; Schaeverbeke, Jolien; Bastin, Christine; Neyens, Veerle; Bruffaerts, Rose; De Weer, An-Sofie; Seghers, Alexandra; Sunaert, Stefan; Van Laere, Koen; Versijpt, Jan; Vandenbulcke, Mathieu; Salmon, Eric; Todd, James T.; Orban, Guy A.

2015-01-01

Posterior cortical atrophy (PCA) is a rare focal neurodegenerative syndrome characterized by progressive visuoperceptual and visuospatial deficits, most often due to atypical Alzheimer's disease (AD). We applied insights from basic visual neuroscience to analyze 3D shape perception in humans affected by PCA. Thirteen PCA patients and 30 matched healthy controls participated, together with two patient control groups with diffuse Lewy body dementia (DLBD) and an amnestic-dominant phenotype of AD, respectively. The hierarchical study design consisted of 3D shape processing for 4 cues (shading, motion, texture, and binocular disparity) with corresponding 2D and elementary feature extraction control conditions. PCA and DLBD exhibited severe 3D shape-processing deficits and AD to a lesser degree. In PCA, deficient 3D shape-from-shading was associated with volume loss in the right posterior inferior temporal cortex. This region coincided with a region of functional activation during 3D shape-from-shading in healthy controls. In PCA patients who performed the same fMRI paradigm, response amplitude during 3D shape-from-shading was reduced in this region. Gray matter volume in this region also correlated with 3D shape-from-shading in AD. 3D shape-from-disparity in PCA was associated with volume loss slightly more anteriorly in posterior inferior temporal cortex as well as in ventral premotor cortex. The findings in right posterior inferior temporal cortex and right premotor cortex are consistent with neurophysiologically based models of the functional anatomy of 3D shape processing. However, in DLBD, 3D shape deficits rely on mechanisms distinct from inferior temporal structural integrity. SIGNIFICANCE STATEMENT Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visuoperceptual dysfunction and most often an atypical presentation of Alzheimer's disease (AD) affecting the ventral and dorsal visual streams rather than the medial

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.

Simulated type II superior labral anterior posterior lesions do not alter the path of glenohumeral articulation: a cadaveric biomechanical study.

PubMed

Youm, Thomas; Tibone, James E; ElAttrache, Neal S; McGarry, Michelle H; Lee, Thay Q

2008-04-01

model as quantified by the path of glenohumeral articulation. Findings suggest that in the absence of pain or mechanical symptoms, type II superior labral anterior posterior lesions that do not significantly involve the superior and middle glenohumeral ligaments may not need surgical repair.

In Vivo Detection of Laminar and Peripapillary Scleral Hypercompliance in Early Monkey Experimental Glaucoma

PubMed Central

Ivers, Kevin M.; Yang, Hongli; Gardiner, Stuart K.; Qin, Lirong; Reyes, Luke; Fortune, Brad; Burgoyne, Claude F.

2016-01-01

Purpose To compare optical coherence tomography (OCT) detected, optic nerve head (ONH) compliance within control and experimental glaucoma (EG) eyes of 15 monkeys at EG onset. Methods Intraocular pressure (IOP) was chronically elevated in one eye of each animal using a laser. Experimental glaucoma onset was identified using confocal scanning laser tomography (CSLT). Optical coherence tomography ONH imaging (40 radial B-scans) was performed at 10 mm Hg before and after laser. At EG onset, OCT scans were obtained at IOP 10 and 30 mm Hg. Optical coherence tomography landmarks within the IOP 10/30 images were delineated to quantify IOP 10/30 differences (compliance) for anterior lamina cribrosa surface depth (ALCSD) relative to Bruch's membrane opening (BMO) (ALCSD-BMO), ALCSD relative to peripheral BM (ALCSD-BM), and BMO depth relative to peripheral BM (BMOD-BM). A linear mixed effects model assessed for acute IOP elevation effects, control versus EG eye effects, and their interaction Results Effects of IOP elevation were greater in EG versus control eyes for ALCSD-BMO (−46 ± 45 vs. −8 ± 13 μm, P = 0.0042) and ALCSD-BM (−92 ± 64 vs. −42 ± 22 μm, P = 0.0075). Experimental glaucoma eye-specific ALCSD-BMO and ALCSD-BM compliance exceeded the range of control eye compliance in 9 and 8 of the 15 EG eyes, respectively. Post-laser peak IOP (R2 = 0.798, P < 0.0001) and post-laser mean IOP (R2 = 0.634, P < 0.0004) most strongly correlated to EG versus control eye differences in ALCSD-BMO compliance. Conclusions Laminar (ALCSD-BMO) and peripapillary scleral (ALCSD-BM) hypercompliance are present in most monkey eyes at the onset of EG. PMID:27409498

Conjunctival impression cytology evaluation of patients with dry eye disease using scleral contact lenses.

PubMed

Weber, Sarah La Porta; Hazarbassanov, Rossen Mihaylov; Nasaré, Alex; Gomes, José Álvaro Pereira; Hofling-Lima, Ana Luisa

2017-06-01

To evaluate conjunctival impression cytology and HLADR expression changes after wearing scleral contact lenses (ScCLs) for moderate to severe dry eye disease (DED). Prospective interventional case series. Forty-one eyes from 25 patients with moderate to severe DED were evaluated for Esclera ScCL treatment. Best-corrected visual acuity (BCVA) and slit-lamp findings were assessed. Impression cytology specimens were obtained from DED patients at the baseline and after wearing ScCLs for 12 months. The impression cytology specimens were analyzed using morphological results score, and HLA-DR positive cells were detected and quantified. The values were compared to assess the IC changes after wearing ScCLs. Forty-one eyes from 25 patients were fitted with ScCLs to manage DED. The underlying diseases were Stevens-Johnson syndrome (22 eyes), Sjogren's syndrome (11 eyes), graft-versus-host disease (2 eyes), dry eye after keratomileusis (2 eyes) and undifferentiated ocular surface disease (4 eyes). The HE-PAS impression cytology score did not differ significantly before and after wearing ScCLs for 12 months in DED patients (p>0.05). The percentage of eyes expressing the HLA-DR antigen in the temporal conjunctiva after wearing ScCL for 12 months significantly increased in patients with Sjogren's syndrome (11.11% to 66.66%; p=0.0498). In groups with Stevens Johnson syndrome and other ocular surface disorders, we did not observe statistically significant differences (p>0.05). The ScCLs did not change the parameters used to evaluate inflammatory processes, which were measured using conjunctival impression cytology and HLA-DR expression, except in Sjogren syndrome, in which there was an unexpected increase in HLA expression. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Poly-N-isopropylacrylamide (pNIPAM): a reversible bioadhesive for sclerotomy closure.

PubMed

Lima, Luiz H; Morales, Yael; Cabral, Thiago

2016-01-01

To determine the safety and efficacy of poly- N -isopropylacrylamide, a thermoresponsive adhesive, for sutureless sclerotomy closure in rabbits. Eight rabbits were randomized into three groups: short-term acute, mid-term chronic, and long-term chronic studies. A corresponding control group in which the scleral wounds were sutured by 6-0 vicryl sutures was assigned for each study group. A 20-gauge sclerotomy was performed following a core vitrectomy and 0.1 mL of 50 % liquid poly- N -isopropylacrylamide was applied to the scleral wounds. Before the polymer application, the scleral surface was raised above 32 °C using a halogen bulb lamp. Follow-up exams included color external and fundus photography, fundus fluorescein angiography, optical coherence tomography, and electroretinography. After the last follow-up assessment, the rabbits were sacrificed and histopathological studies on the scleral incision sites were performed. Scleral wound healing was observed in the long-term chronic study rabbits. Histological studies were able to identify poly- N -isopropylacrylamide polymer at the sclerotomy site in the mid-term chronic study rabbits. Besides iatrogenic cataracts due to mechanical instrument touch in 2 rabbits, no other ocular abnormalities were identified in any of the eyes in the perioperative setting or during the follow-up period. Cornea, retina, and vitreous remained unaffected, and no abnormal inflammatory reaction or endophthalmitis was noticed in the 3 study groups. Filtering blebs indicative of leakage through the sclerotomies were not observed during the follow-up period. Poly- N -isopropylacrylamide may provide effective in vitro scleral adhesion above 32 °C. Clinical studies are required to evaluate its utility in patients undergoing pars plana vitrectomy.

Comparative Biomechanical Study on Contact Alterations After Lateral Meniscus Posterior Root Avulsion, Transosseous Reinsertion, and Total Meniscectomy.

PubMed

Perez-Blanca, Ana; Espejo-Baena, Alejandro; Amat Trujillo, Daniel; Prado Nóvoa, María; Espejo-Reina, Alejandro; Quintero López, Clara; Ezquerro Juanco, Francisco

2016-04-01

To compare the effects of lateral meniscus posterior root avulsion left in situ, its repair, and meniscectomy on contact pressure distribution in both tibiofemoral compartments at different flexion angles. Eight cadaveric knees were tested under compressive 1000 N load for 4 lateral meniscus conditions (intact, posterior root avulsion, transosseous root repair, and total meniscectomy) at flexion angles 0°, 30°, 60°, and 90°. Contact area and pressure distribution were registered using K-scan pressure sensors inserted between menisci and tibial plateau. In the lateral compartment, root detachment decreased contact area (P = .017, 0° and 30°; P = .012, 60° and 90°) and increased mean (P = .012, all angles) and maximum (P = .025, 0° and 30°; P = .017, 60°; P = .012, 90°) pressures relative to intact condition. Repair restored all measured parameters close to intact at 0°, but effectiveness decreased with flexion angle, yielding no significant effect at 90°. Meniscectomy produced higher decreases than root avulsion in contact area (P = .012, 0° and 90°; P = .05, 30° and 60°) and increases in mean (P = .017, 0° and 30°; P = .018, 90°) and maximum pressure (P = .012, 0°; P = .036, 30°). In the medial compartment, lesion changed the contact area at high flexion angles only, while meniscectomy induced greater changes at all angles. Lateral meniscus posterior root avulsion generates significant alterations in contact area and pressures at lateral knee compartment for flexion angles between full extension and 90°. Meniscectomy causes greater disorders than the avulsion left in situ. Transosseous repair with a single suture restores these alterations to conditions close to intact at 0° and 30° but not at 60° and 90°. Altered contact mechanics after lateral meniscus posterior root avulsion might have degenerative consequences. Transosseous repair with one suture should be revised to effectively restore contact mechanics at high flexion angles

Improvising a Posterior Nasal Pack with Equipment in a Basic First Aid Kit.

PubMed

Royer, Allison K; Royer, Mark C

2016-09-01

Posterior epistaxis is a serious condition that can be difficult to treat in a wilderness setting. The initial standard of care involves packing the affected nostril with a 7 to 9 cm nasal pack to tamponade the bleed. These packs are often unavailable outside of the emergency or operating room. This study set out to determine whether a posterior nasal pack could be constructed from the supplies present in a basic first aid kit in order to control massive nasal hemorrhage in a wilderness setting. A basic first aid kit was utilized to construct a posterior nasal pack that was inserted into an anatomical model and visibly compared with the Rapid Rhino (Posterior, 7.5 cm; Smith & Nephew, Austin, TX) nasal packing. The shape, size, and anatomical areas of compression (ie, into nasopharynx and posterior aspect of inferior turbinate) of this pack was similar to the commercially available posterior nasal pack. Placement in an anatomical model appears to provide similar compression as the commercially available posterior pack. This technique may provide short-term hemorrhage control in cases of serious posterior nasal hemorrhage where standard treatment options are not available. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Posterior rectus sheath hernia causing intermittent small bowel obstruction.

PubMed

Lenobel, Scott; Lenobel, Robert; Yu, Joseph

2014-09-01

A posterior rectus sheath hernia is an abdominal wall hernia that is rarely encountered. Owing to its rarity, it can be easily overlooked in the setting of a patient presenting with abdominal pain. We report a case of a posterior rectus sheath hernia that caused intermittent small bowel obstruction. The unusual aspects of this case are that the defect was large, measuring 6 cm in the transverse diameter, and that it contained small bowel within a large portion of the rectus sheath. Because the defect was large and affected nearly the entire posterior rectus sheath, it was difficult to discern on computed tomography until a small bowel obstruction developed. In this case, a limited awareness of this clinical entity contributed to the delay in diagnosis.

Posterior Rectus Sheath Hernia Causing Intermittent Small Bowel Obstruction

PubMed Central

Lenobel, Scott; Lenobel, Robert; Yu, Joseph

2014-01-01

A posterior rectus sheath hernia is an abdominal wall hernia that is rarely encountered. Owing to its rarity, it can be easily overlooked in the setting of a patient presenting with abdominal pain. We report a case of a posterior rectus sheath hernia that caused intermittent small bowel obstruction. The unusual aspects of this case are that the defect was large, measuring 6 cm in the transverse diameter, and that it contained small bowel within a large portion of the rectus sheath. Because the defect was large and affected nearly the entire posterior rectus sheath, it was difficult to discern on computed tomography until a small bowel obstruction developed. In this case, a limited awareness of this clinical entity contributed to the delay in diagnosis. PMID:25426248

The presence and influence of posterior capsule tightness on different shoulder problems.

PubMed

Duzgun, Irem; Turgut, Elif; Çinar-Medeni, Özge; Kafa, Nihan; Tuna, Zeynep; Elbasan, Bulent; Oskay, Deran

2017-01-01

In the literature it has been shown that posterior capsule flexibility is a precursor to shoulder problems. However, no study thus far has shown the influence of the flexibility of posterior capsule in different shoulder pathologies. This study set about to compare the role of posterior capsule tightness in different shoulder problems. One-hundred-twenty-five patients diagnosed with shoulder subacromial impingement syndrome (n= 52), partial rotator cuff tear (n= 31) or frozen shoulder (n= 42) and 30 asymptomatic peers participated in the study. Horizontal adduction was assessed in side-lying position for posterior capsule tightness. Pain was measured via the visual analogue scale and shoulder range of motion and active total elevation was assessed with goniometer. Hand behind the back (HBB) test was assessed the active internal rotation by measuring the distance between T5 and the thumb. It was found that the affected side of the posterior capsules of the patients with subacromial impingement syndrome (p< 0.001), partial rotator cuff tear (p< 0.001) and frozen shoulder (p< 0.001) was stiffer than their healthy side. There were significant differences among groups in the level of tightness in the posterior capsule between the affected and the healthy sides (p< 0.001). All range of motion of the shoulder including HBB test and the posterior capsule tightness of the affected side are found to be correlated (p< 0.05). This study emphasized that the posterior capsule's susceptibility to tightness is most evident in frozen shoulder among different shoulder problems.

En-masse protraction of mandibular posterior teeth into missing mandibular lateral incisor spaces using a fixed functional appliance.

PubMed

Chhibber, Aditya; Upadhyay, Madhur

2016-11-01

Protraction of mandibular posterior teeth requiring absolute anchorage has always been a challenge, especially when the space is located in the anterior region, since more teeth must be protracted. Traditionally, skeletal anchorage devices have been used for anchorage reinforcement during protraction. However, drawbacks such as requirement of a surgical step, inability to tolerate heavy forces, and patient willingness to undergo such surgical procedures can be limiting factors. Additionally, the mechanics involved can sometimes create undesirable side effects, thereby limiting their application in such situations. This report describes the use of a fixed functional appliance as an anchorage-reinforcement device for en-masse protraction of mandibular posterior teeth into a missing lateral incisor space. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Occlusion of pressor responses to posterior diencephalic stimulation and muscular contraction.

PubMed

Rybicki, K J; Stremel, R W; Iwamoto, G A; Mitchell, J H; Kaufman, M P

1989-02-01

Although neural occlusion has been suggested to occur between the central and reflex mechanisms increasing arterial pressure, evidence consistent with this phenomenon is lacking. To assess the possibility of neural occlusion we recorded, in chloralose-anesthetized cats, the pressor responses to statically contracting the hindlimb muscles and to electrically stimulating histologically confirmed sites in the posterior hypothalamus and subthalamus. We also recorded the pressor responses to topical application of capsaicin onto the intestine and to stimulation of these diencephalic sites. The pressor responses to simultaneous static contraction and diencephalic stimulation were significantly smaller than the algebraic sum of the pressor responses to contraction and diencephalic stimulation evoked separately. Likewise, the pressor responses to simultaneous capsaicin application and diencephalic stimulation were significantly smaller than the algebraic sum of the responses evoked separately. High intensity stimulation of the L7 dorsal root or the diencephalic sites evoked pressor responses similar in magnitude to the algebraic sum of the two responses evoked separately; thus, the inability of the simultaneous maneuvers to evoke pressor responses that summed algebraically was not due to the fact that they caused a maximal effect. Our findings are consistent with the hypothesis that neural occlusion occurs during stimulation of the posterior diencephalon and static muscular contraction.

Clinical Outcomes and Return to Sport After Arthroscopic Anterior, Posterior, and Combined Shoulder Stabilization

PubMed Central

Kraeutler, Matthew J.; Aberle, Nicholas S.; Brown, Colin C.; Ptasinski, Joseph J.; McCarty, Eric C.

2018-01-01

Background: Glenohumeral instability is a common abnormality, especially among athletes. Previous studies have evaluated outcomes after arthroscopic stabilization in patients with anterior or posterior shoulder instability but have not compared outcomes between groups. Purpose: To compare return-to-sport and other patient-reported outcomes in patients after primary arthroscopic anterior, posterior, and combined anterior and posterior shoulder stabilization. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent primary arthroscopic anterior, posterior, or combined anterior and posterior shoulder stabilization were contacted at a minimum 2-year follow-up. Patients completed a survey that consisted of return-to-sport outcomes as well as the Western Ontario Shoulder Instability Index (WOSI), Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Sur’geons (ASES) score, and Shoulder Activity Scale. Results: A total of 151 patients were successfully contacted (anterior: n = 81; posterior: n = 22; combined: n = 48) at a mean follow-up of 3.6 years. No significant differences were found between the groups with regard to age at the time of surgery or time to follow-up. No significant differences were found between the groups in terms of WOSI (anterior: 76; posterior: 70; combined: 78; P = .28), SANE (anterior: 87; posterior: 85; combined: 87; P = .79), ASES (anterior: 88; posterior: 83; combined: 91; P = .083), or Shoulder Activity Scale (anterior: 12.0; posterior: 12.5; combined: 12.5; P = .74) scores. No significant difference was found between the groups in terms of the rate of return to sport (anterior: 73%; posterior: 68%; combined: 75%; P = .84). Conclusion: Athletes undergoing arthroscopic stabilization of anterior, posterior, or combined shoulder instability can be expected to share a similar prognosis. High patient-reported outcome scores and moderate to high rates of return to sport were achieved by all groups. PMID

Partial-coverage posterior ceramic restorations. Part 1: a return to diligence.

PubMed

Liebenberg, W H

2001-01-01

The application of multisurfaced tooth-colored restorations in the posterior dentition is an exercise in risk tolerance when dentin occupies the bulk of the tooth substrate. Not only is interfacial integrity capricious, but also a recent in vivo study has confirmed that dentin bond strengths deteriorate with time. Although the literature is replete with esthetic guidelines for posterior restitution, most practicing clinicians appreciate the prime tenet that clinical success involves more than esthetic realism in the posterior dentition. Success with indirect ceramic restorations is dependent on interfacial integrity, which, although multitudinous, is contingently related to operative competence. Innovative clinical techniques are described in this two-part article, along with a discussion of the probationary status of current adhesive options and the need for excellence in all phases of this demanding restorative sequence. Restorative success in the posterior dentition is profoundly influenced by the variability of operative competence and diligence. This article discusses the precincts of posterior indirect ceramic restorations and submits a number of innovative solutions to the clinical challenge.

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.

Bayesian approach to inverse statistical mechanics.

PubMed

Habeck, Michael

2014-05-01

Inverse statistical mechanics aims to determine particle interactions from ensemble properties. This article looks at this inverse problem from a Bayesian perspective and discusses several statistical estimators to solve it. In addition, a sequential Monte Carlo algorithm is proposed that draws the interaction parameters from their posterior probability distribution. The posterior probability involves an intractable partition function that is estimated along with the interactions. The method is illustrated for inverse problems of varying complexity, including the estimation of a temperature, the inverse Ising problem, maximum entropy fitting, and the reconstruction of molecular interaction potentials.

Bayesian approach to inverse statistical mechanics

NASA Astrophysics Data System (ADS)

Habeck, Michael

2014-05-01

Inverse statistical mechanics aims to determine particle interactions from ensemble properties. This article looks at this inverse problem from a Bayesian perspective and discusses several statistical estimators to solve it. In addition, a sequential Monte Carlo algorithm is proposed that draws the interaction parameters from their posterior probability distribution. The posterior probability involves an intractable partition function that is estimated along with the interactions. The method is illustrated for inverse problems of varying complexity, including the estimation of a temperature, the inverse Ising problem, maximum entropy fitting, and the reconstruction of molecular interaction potentials.

[Manual rotation of occiput posterior presentation].

PubMed

Le Ray, C; Goffinet, F

2011-10-01

Delivery in occiput posterior position is associated with a higher risk of cesarean section, operative vaginal delivery and severe perineal tears. We report the technic of manual rotation described by Tarnier and Chantreuil and used daily in our maternity center. Only five studies were published on this topic; all of them demonstrate that manual rotation decreases the risk of cesarean section. Moreover, it could decrease the risk of prolonged second stage, chorioamnionitis and third and fourth degree tears in comparison with expectant management. However, manual rotation is associated with a two-fold higher risk of cervical and vaginal lacerations. Manual rotation performed with an adequate technic is an efficient and safe manœuvre to avoid complications associated with occiput posterior vaginal delivery. Copyright © 2011. Published by Elsevier SAS.

Posterior epistaxis: Common bleeding sites and prophylactic electrocoagulation.

PubMed

Liu, Juan; Sun, Xicai; Guo, Limin; Wang, Dehui

2016-01-01

Posterior epistaxis is a frequent emergency, and the key to efficient management is identification of the bleeding point. We performed a retrospective study of 318 patients with posterior epistaxis treated with endoscopic bipolar electrocautery during a 4-year period. Distribution of the bleeding sites was recorded. Patients with no definite bleeding sites in the first operation were assigned to Group A (n = 39) and Group B (n = 34). Patients in Group A were only observed in the ward. Patients in Group B were given prophylactic electrocoagulation at the common bleeding points. Of the 318 patients, bleeding sites were successfully identified and coagulated in 263 patients. All of them were located posteriorly, with 166 on the lateral nasal wall, 86 on the septum, and 11 on the anterior face of the sphenoid sinus. The rebleeding rate of Group B (8.8%) was lower than that of Group A (38.5%) (p < 0.01).

Meta-analysis of posterior versus medial approach for popliteal artery aneurysm repair.

PubMed

Phair, Alison; Hajibandeh, Shahin; Hajibandeh, Shahab; Kelleher, Damian; Ibrahim, Riza; Antoniou, George A

2016-10-01

Popliteal artery aneurysm is an uncommon vascular disease but one that can cause significant morbidity, the most severe being limb loss reported in 20% to 59% of cases. Two approaches to repair are described in the literature, the posterior and the medial; however, the "gold standard" method of repair remains controversial. A systematic review of electronic information sources was undertaken to identify papers comparing outcomes of posterior repair vs medial repair. The methodologic quality of the papers was assessed using the Newcastle-Ottawa Scale. Fixed-effect or random-effects models were applied to synthesize data. The search yielded seven articles eligible for inclusion. The total population comprised 1427 patients; 338 had posterior repair and 1089 had medial repair. There was no difference in the two groups in terms of postoperative nerve damage (odds ratio [OR], 1.01; 95% confidence interval [CI], 0.24-4.2) and 30-day postoperative complications (OR, 0.87; 95% CI, 0.43-1.77). Limb loss at 30 days occurred more frequently in the medial approach group, but the difference was not statistically significant (risk difference [RD], 0.02; 95% CI, -0.04 to 0.00). Thirty-day primary patency was not statistically different between groups (RD, -0.01; 95% CI, -0.04 to 0.02), but the 30-day secondary patency suggested superiority of the posterior approach (RD, 0.05; 95% CI, 0.02-0.07). Long-term primary and secondary patency both favored the posterior approach (OR, 1.61 [95% CI, 1.06-2.43] and OR, 1.73 [95% CI, 0.91-3.30], respectively). Aneurysm exclusion was also superior with the posterior approach (OR, 4.20; 95% CI, 1.40-12.60). The rate of reoperation favored the posterior approach (OR, 0.26; 95% CI, 0.09-0.72). Long-term risk of limb loss favored posterior repair, but no statistically significant difference was found (OR, 0.32; 95% CI, 0.43-1.77). High-level comparative data comparing posterior and medial repair for popliteal artery aneurysms are not available

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

Robotic Posterior Mitral Leaflet Repair: Neochordal versus Resectional Techniques

PubMed Central

Mihaljevic, Tomislav; Pattakos, Gregory; Gillinov, A. Marc; Bajwa, Gurjyot; Planinc, Mislav; Williams, Sarah J.; Blackstone, Eugene H.

2013-01-01

Background Resectional techniques are the established method of posterior mitral valve leaflet repair for degenerative disease; however, use of neochordae in a robotically assisted approach is gaining acceptance because of its versatility for difficult multi-segment disease. The purposes of this study were to compare the versatility, safety, and effectiveness of neochordal vs. resectional techniques for robotic posterior mitral leaflet repair. Methods From 12/2007 to 7/2010, 334 patients underwent robotic posterior mitral leaflet repair for degenerative disease by a resectional (n=248) or neochordal (n=86) technique. Outcomes were compared unadjusted and after propensity score matching. Results Neochordae were more likely to be used than resection in patients with two (28% vs. 13%, P=.002) or three (3.7% vs. 0.87%, P=.08) diseased posterior leaflet segments. Three resection patients (0.98%) but no neochordal patient required reoperation for hemodynamically significant systolic anterior motion (SAM). Residual mitral regurgitation (MR) at hospital discharge was similar for matched neochordal vs. resection patients (P=.14) (MR 0+, 82% vs. 89%; MR 1+, 14% vs. 8.2%; MR 2+, 2.3% vs. 2.6%; one neochordal patient had 4+ MR and was reoperated). Among matched patients, postoperative mortality and morbidity were similarly low. Conclusion Compared with a resectional technique, robotic posterior mitral leaflet repair with neochordae is associated with shorter operative times and no occurrence of SAM. The versatility, effectiveness, and safety of this repair make it a good choice for patients with advanced multi-segment disease. PMID:23103008

Preformed posterior stainless steel crowns: an update.

PubMed

Croll, T P

1999-02-01

For almost 50 years, dentists have used stainless steel crowns for primary and permanent posterior teeth. No other type of restoration offers the convenience, low cost, durability, and reliability of such crowns when interim full-coronal coverage is required. Preformed stainless steel crowns have improved over the years. Better luting cements have been developed and different methods of crown manipulation have evolved. This article reviews stainless steel crown procedures for primary and permanent posterior teeth. Step-by-step placement of a primary molar stainless steel crown is documented and permanent molar stainless steel crown restoration is described. A method for repairing a worn-through crown also is reviewed.

Posterior Mandibular Ridge Resorption Associated with Different Retentive Systems for Overdentures: A 7-Year Retrospective Preliminary Study.

PubMed

Elsyad, Moustafa Abdou; Mohamed, Shahinaz Sayed; Shawky, Ahmad Fathalla

This retrospective study compared posterior mandibular residual ridge resorption with two different retentive mechanisms for overdentures after 7 years. A convenience sample of 18 edentulous men was assigned to one of two equal groups. Two implants were placed in the mandibular canine areas for each patient using the conventional two-stage surgical protocol, and the implants were splinted with a round bar 3 months later. New mandibular overdentures were then connected to the bars with clips (clip-retained overdentures, CR group) or resilient liners (resilient liner-retained overdentures, RR group). Posterior mandibular ridge resorption (PMRR) was recorded using proportional measurements and posterior area index (PAI) on panoramic radiographs taken immediately after overdenture insertion (T 0 ) and 7 years later (T 7 ). A linear regression model was used to verify the relationship between PAI and the following considerations: attachment type, age, initial mandibular ridge height, period of mandibular edentulism, number of previously worn dentures, and relining events. After 7 years, the RR group demonstrated a significantly (P = .014) higher change in PAI (0.11 ± 0.02) than the CR group (0.06 ± 0.04). The average PMRR for each mm of posterior mandibular ridge was 0.79 mm (0.11 mm/year) in the CR group and 1.4 mm (0.2 mm/year) in the RR group. Attachment type, initial mandibular ridge height, and relining times were significantly correlated with change in the PAI (P = .004, P = .035, and P = .045, respectively). Within the limitations of this preliminary study's design, it was observed that following a 7-year period of use, resilient liner attachments for bar/implant-retained overdentures appear to be associated with greater posterior mandibular ridge resorption when compared to clip attachments.

Ultrasound assessment of hamstring muscle size using posterior thigh muscle thickness.

PubMed

Abe, Takashi; Loenneke, Jeremy P; Thiebaud, Robert S

2016-05-01

Several studies have investigated the relationship between ultrasound-measured muscle thickness (MT) and individual muscle cross-sectional area (CSA) and muscle volume (MV) in extremity and trunk muscles; however, the hamstring muscle has not been studied. The purpose of this study was to examine the relationship between posterior thigh MT by ultrasound and the muscle CSA and MV of the hamstring obtained by magnetic resonance imaging (MRI). Ten young women aged 20-31 had MT measured by ultrasound at three sites on the medial anterior (50% of thigh length; TL) and posterior (50% and 70% of TL) aspects of the thigh. On the same day, a series of continuous muscle CSA along the thigh was measured by MRI. In each slice, the anatomical CSA of the hamstring (biceps femoris, semitendinosus and semimembranosus) and quadriceps muscle was analysed, and the CSAs at 50% and 70% of TL and maximal CSA of the hamstring (CSAmax ) were determined. MV was calculated by multiplying CSA by slice thickness. A significant correlation was observed between posterior 50% MT and 50% hamstring CSA (r = 0·848, P = 0·002) and between posterior 70% MT and 70% hamstring CSA (r = 0·679, P = 0·031). Posterior 50% MT (r = 0·732, P = 0·016) and 50% MTxTL (r = 0·873, P = 0·001) were also correlated to hamstring MV. Anterior:posterior 50% thigh MT ratio was correlated to MV ratio of quadriceps and hamstring muscles (r = 0·803, P = 0·005). Our results suggest that posterior thigh MT reflects hamstring muscle CSA and MV. The anterior:posterior MT ratio may serve as a surrogate for MV ratio of quadriceps and hamstring. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Altered tibiofemoral contact mechanics due to lateral meniscus posterior horn root avulsions and radial tears can be restored with in situ pull-out suture repairs.

PubMed

LaPrade, Christopher M; Jansson, Kyle S; Dornan, Grant; Smith, Sean D; Wijdicks, Coen A; LaPrade, Robert F

2014-03-19

An avulsion of the posterior root attachment of the lateral meniscus or a radial tear close to the root attachment can lead to degenerative knee arthritis. Although the biomechanical effects of comparable injuries involving the medial meniscus have been studied, we are aware of no such study involving the lateral meniscus. We hypothesized that in situ pull-out suture repair of lateral meniscus root avulsions and of complete radial tears 3 and 6 mm from the root attachment would increase the contact area and decrease mean and peak tibiofemoral contact pressures, at all knee flexion angles, relative to the corresponding avulsion or tear condition. Eight human cadaveric knees underwent biomechanical testing. Eight lateral meniscus conditions (intact, footprint tear, root avulsion, root avulsion repair, radial tears at 3 and 6 mm from the posterior root, and repairs of the 3 and 6-mm tears) were tested at five different flexion angles (0°, 30°, 45°, 60°, and 90°) under a compressive 1000-N load. Avulsion of the posterior root of the lateral meniscus or an adjacent radial tear resulted in significantly decreased contact area and increased mean and peak contact pressures in the lateral compartment, relative to the intact condition, in all cases except the root avulsion condition at 0° of flexion. In situ pull-out suture repair of the root avulsion or radial tear significantly reduced mean contact pressures, relative to the corresponding avulsion or tear condition, when the results for each condition were pooled across all flexion angles. Posterior horn root avulsions and radial tears adjacent to the root attachment of the lateral meniscus significantly increased contact pressures in the lateral compartment. In situ pull-out suture repairs of these tears significantly improved lateral compartment joint contact pressures. In situ repair may be an effective treatment to improve tibiofemoral contact profiles after an avulsion of the posterior root of the lateral

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.

Parascapular mass revealing primary tuberculosis of the posterior arch

PubMed Central

Arbault, Anais; Ornetti, Paul; Chevallier, Olivier; Avril, Julien; Pottecher, Pierre

2016-01-01

We report the case of a parascapular abscess revealing primary tuberculosis of the posterior arch in a 31-year-old man. Sectional imaging is essential in order to detect the different lesions of this atypical spinal tuberculosis as osteolysis of the posterior arch extendible to vertebral body, osteocondensation, epidural extension which is common in this location, and high specificity of a zygapophysial, costo-vertebral or transverse arthritis. PMID:27709081

Effect of posterior cruciate ligament rupture on the radial displacement of lateral meniscus.

PubMed

Lei, Pengfei; Sun, Rongxin; Hu, Yihe; Li, Kanghua; Liao, Zhan

2015-06-01

The relationship between lateral meniscus tear and posterior cruciate ligament injury is not well understood. The present study aims to investigate and assess the effect of posterior cruciate ligament rupture on lateral meniscus radial displacement at different flexion angles under static loading conditions. Twelve fresh human cadaveric knee specimens were divided into four groups such as posterior cruciate ligament intact, anterolateral band rupture, posteromedial band rupture and posterior cruciate ligament complete rupture groups, according to the purpose and order of testing. Radial displacement of lateral meniscus was measured under different loads (200-1000N) at 0°, 30°, 60°, and 90° of knee flexion. Compared with posterior cruciate ligament intact group, the displacement values of lateral meniscus in anterolateral band rupture group increased at 0° flexion with 600N, 800N, and 1000N and at 30°, 60° and 90° flexion under all loading conditions. Posteromedial band rupture group exhibited higher displacement at 0° flexion under all loading conditions, at 30° and 60° flexion with 600, 800N and 1000N, and at 90° flexion with 400N, 600N, 800N, and 1000N than the posterior cruciate ligament intact group. The posterior cruciate ligament complete rupture group had a higher displacement value of lateral medial meniscus at 0°, 30°, 60° and 90° flexion under all loading conditions, as compared to the posterior cruciate ligament intact group. The study concludes that partial and complete rupture of the posterior cruciate ligament can trigger the increase of radial displacement on lateral meniscus. Copyright © 2015 Elsevier Ltd. All rights reserved.

Indocyanine green angiography in posterior uveitis

PubMed Central

Agrawal, Rupesh V; Biswas, Jyotirmay; Gunasekaran, Dinesh

2013-01-01

Literature review for indocyanine green angiography and evaluate the role of indocyanine green angiogram (ICGA) in patients with posterior uveitis seen at a tertiary referral eye care centre. Detailed review of the literature on ICGA was performed. Retrospective review of medical records of patients with posterior uveitis and dual fundus and ICGA was done after institutional board approval. Eighteen patients (26 eyes) had serpiginous choroiditis out of which 12 patients had active choroiditis and six patients had healed choroiditis, six patients (12 eyes) had ampiginous choroiditis, six patients (12 eyes) had acute multifocal posterior placoid pigment epitheliopathy, eight patients (10 eyes) had multifocal choroiditis, four patients (eight eyes) had presumed ocular histoplasmosis syndrome, four patients (eight eyes) had presumed tuberculous choroiditis, two patients (four eyes) had multiple evanescent white dot syndrome and two patients (four eyes) had Vogt Koyanagi Harada (VKH) syndrome. The most characteristic feature noted on ICGA was the presence of different patterns of hypofluorescent dark spots, which were present at different stages of the angiogram. ICGA provides the clinician with a powerful adjunctive tool in choroidal inflammatory disorders. It is not meant to replace already proven modalities such as the fluorescein angiography, but it can provide additional information that is useful in establishing a more definitive diagnosis in inflammatory chorioretinal diseases associated with multiple spots. It still needs to be determined if ICGA can prove to be a follow up parameter to evaluate disease progression. PMID:23685486

Posterior thalamic hemorrhage induces "pusher syndrome".

PubMed

Karnath, Hans-Otto; Johannsen, Leif; Broetz, Doris; Küker, Wilhelm

2005-03-22

Recent findings argue for a pathway in humans for sensing the orientation of gravity and controlling upright body posture, separate from the one for orientation perception of the visual world. Stroke patients with contraversive pushing were shown to experience their body as oriented upright when actually tilted about 20 degrees to the ipsilesional side, in spite of normal visual-vestibular functioning. A recent study suggested the involvement of posterolateral thalamus typically associated with the disorder. To evaluate the relationship between pushing behavior and thalamic function. Over a 3-year period the authors prospectively investigated 40 patients with left- or right-sided thalamic strokes. Twenty-eight percent showed contraversive pushing. The authors found a strong relationship between etiology, vascular territory, lesion size, and neurologic disorders associated with contraversive pushing. Pusher patients had larger lesions that typically were caused by hemorrhage (vs infarcts) located in the posterior thalamus (vs anterior thalamic lesions in those patients without pushing behavior). A paresis of the contralesional extremities was more frequent and more severe in pusher patients. Further, these patients showed more additional spatial neglect with right thalamic lesions, while they tended to be more aphasic with left thalamic lesions. Posterior thalamus seems to be fundamentally involved in our control of upright body posture. Higher pressure, swelling, and other secondary pathologic processes associated with posterior thalamic hemorrhage (vs thalamic infarction) may provoke contraversive pushing in combination with additional neurologic symptoms.

Posterior dislocation following revision total knee replacement arthroplasty: a case report and literature analysis.

PubMed

Lee, Ho Min; Kim, Jong Pil; Chung, Phil Hyun; Kang, Suk; Kim, Young Sung; Go, Bo Seong

2018-05-24

Knee dislocation following total knee replacement arthroplasty is a rare but serious complication. The incidence of dislocation following primary total knee arthroplasty with posterior stabilized implants ranges from 0.15 to 0.5%, and posterior dislocation after revision total knee arthroplasty is even rarer. Here, we report the case of a 76-year-old male who presented with posterior dislocation after posterior stabilized revision total knee arthroplasty.

Cervical disc hernia operations through posterior laminoforaminotomy.

PubMed

Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

2016-01-01

The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The Nd:YAG...

21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The Nd:YAG...

21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The Nd:YAG...

21 CFR 886.4392 - Nd:YAG laser for posterior capsulotomy and peripheral iridotomy.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nd:YAG laser for posterior capsulotomy and...:YAG laser for posterior capsulotomy and peripheral iridotomy. (a) Identification. The Nd:YAG laser for... laser intended for disruption of the posterior capsule or the iris via optical breakdown. The Nd:YAG...

Drug delivery to the posterior segment of the eye through hydrogel contact lenses.

PubMed

Schultz, Clyde; Breaux, Jason; Schentag, Jerome; Morck, Douglas

2011-03-01

Despite pharmacological advances, delivery of drugs to the posterior segment of the eye remains problematic. We investigated the ability of hydrogel contact lenses to deliver small-molecule steroids, as well as larger biological molecules to the posterior segment. Release characteristics of steroid-instilled lenses were studied in vitro. Drug delivery to the posterior segment of the eye was evaluated in a rabbit model, in which hydrogel contact lenses treated with diluted steroids (prednisolone or beclomethasone) were placed on rabbit corneas for four hours on days 1, 2, 5, 8 and 10. The amount of drug in plasma, posterior segment tissue and vitreous humour was measured with high-performance liquid chromatography-tandem mass spectrometry. In a further preliminary investigation, two rabbits were treated with ranibizumab. The lenses released prednisolone and beclomethasone in saline over a six-hour period at a declining rate. Prednisolone was found in posterior segment tissue from six of six rabbits at concentrations ranging from 26.8 to 166 ng/g and in vitreous humour from two of six rabbits. Beclomethasone was detected in posterior segment tissue from three rabbits but was not found in the vitreous humour. Ranibizumab was detected in posterior segment tissue in a range from 0.19 ng/mL to 0.5183 ng/mL. Hydrogel contact lenses are a non-invasive, periocular drug delivery device capable of achieving measurable drug levels in posterior segment tissue. © 2010 The Authors. Clinical and Experimental Optometry © 2010 Optometrists Association Australia.

[Posterior ceramic bonded partial restorations].

PubMed

Mainjot, Amélie; Vanheusden, Alain

2006-01-01

Posterior ceramic bonded partial restorations are conservative and esthetic approaches for compromised teeth. Overlays constitute a less invasive alternative for tooth tissues than crown preparations. With inlays and onlays they are also indicated in case of full arch or quadrant rehabilitations including several teeth. This article screens indications and realization of this type of restorations.

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

Posterior Bilateral Intermuscular Approach for Upper Cervical Spine Injuries.

PubMed

Xu, Yong; Xiong, Wei; Han, Sung I I; Fang, Zhong; Li, Feng

2017-08-01

To investigate a novel intermuscular surgical approach for posterior upper cervical spine fixation. Twenty-three healthy volunteers underwent magnetic resonance imaging. By using the magnetic resonance imaging scans in transverse view at the level of lower edge of atlas, the distances from the posterior midline to lateral margin of trapezius, to the medial margin of splenius capitis, and to middle line of semispinalis capitis were recorded. The angle between posterior middle line and the line crossing the lateral margin of trapezius and middle point of ipsilateral pedicles. From October 2009 to May 2013, 12 patients with upper cervical spine injuries were operated via the bilateral intermuscular approach. The time required for surgery, blood loss, and pre- and postoperative visual analogue scale scores were analyzed. The average distance of 0-T was 39.2 ± 7.5 mm, the angle between the approach and posterior middle line was 33.2 ± 8.4°. The surgical time was 78.3 ± 22.5 minutes (45-140 minutes), and the mean intraoperative blood loss was 87.5 ± 44.2 mL (30-200 mL). Preoperative and postoperative visual analogue scale scores were 6.4 ± 0.8 and 1.8 ± 0.7, respectively. The average follow-up time was 19.7 ± 11.5 months (9-48 months). The posterior bilateral intermuscular approach for upper cervical spine injuries is a valid alternative for Hangmans' fractures type I, type II, and type Ia according to Levine and Edwards classification as well as atlantoaxial subluxation caused by upper cervical spine trauma. Copyright © 2017 Elsevier Inc. All rights reserved.

Early effectiveness of endoscopic posterior urethra primary alignment.

PubMed

Kim, Fernando J; Pompeo, Alexandre; Sehrt, David; Molina, Wilson R; Mariano da Costa, Renato M; Juliano, Cesar; Moore, Ernest E; Stahel, Philip F

2013-08-01

Posterior urethra primary realignment (PUPR) after complete transection may decrease the gap between the ends of the transected urethra, tamponade the retropubic bleeding, and optimize urinary drainage without the need of suprapubic catheter facilitating concurrent pelvic orthopedic and trauma procedures. Historically, the distorted anatomy after pelvic trauma has been a major surgical challenge. The purpose of the study was to assess the relationship of the severity of the pelvic fracture to the success of endoscopic and immediate PUPR following complete posterior urethral disruption using the Young-Burgess classification system. A review of our Level I trauma center database for patients diagnosed with pelvic fracture and complete posterior urethral disruption from January 2005 to April 2012 was performed. Pelvic fracture severity was categorized according to the Young-Burgees classification system. Management consisted of suprapubic catheter insertion at diagnosis followed by early urethral realignment when the patient was clinically stable. Failure of realignment was defined as inability to achieve urethral continuity with Foley catheterization. Clinical follow-up consisted of radiologic, pressure studies and cystoscopic evaluation. A total of 481 patients with pelvic trauma from our trauma registry were screened initially, and 18 (3.7%) were diagnosed with a complete posterior urethral disruption. A total of 15 primary realignments (83.3%) were performed all within 5 days of trauma. The success rate of early realignment was 100%. There was no correlation between the type of pelvic ring fracture and the success of PUPR. Postoperatively, 8 patients (53.3%) developed urethral strictures, 3 patients (20.0%) developed incontinence, and 7 patients (46.7%) reported erectile dysfunction after the trauma. The mean follow-up of these patients was 31.8 months. Endoscopic PUPR may be an effective option for the treatment of complete posterior urethral disruption and

Characteristics of Posterior Corneal Astigmatism in Different Stages of Keratoconus.

PubMed

Aslani, Fereshteh; Khorrami-Nejad, Masoud; Aghazadeh Amiri, Mohammad; Hashemian, Hesam; Askarizadeh, Farshad; Khosravi, Bahram

2018-01-01

To evaluate the magnitudes and axis orientation of anterior corneal astigmatism (ACA) and posterior corneal astigmatism (PCA), the ratio of ACA to PCA, and the correlation between ACA and PCA in the different stages of keratoconus (KCN). This retrospective case series comprised 161 eyes of 161 patients with KCN (104 men, 57 women; mean age, 22.35 ± 6.10 years). The participants were divided into four subgroups according to the Amsler-Krumeich classification. A Scheimpflug imaging system was used to measure the magnitude and axis orientation of ACA and PCA. The posterior-anterior corneal astigmatism ratio was also calculated. The results were compared among different subgroups. The average amounts of anterior, posterior, and total corneal astigmatism were 4.08 ± 2.21 diopters (D), 0.86 ± 0.46 D, and 3.50 ± 1.94 D, respectively. With-the-rule, against-the-rule, and oblique astigmatisms of the posterior surface of the cornea were found in 61 eyes (37.9%), 67 eyes (41.6%), and 33 eyes (20.5%), respectively; corresponding figures in the anterior corneal surface were 55 eyes (32.4%), 56 eyes (34.8%), and 50 eyes (31.1%), respectively. A strong correlation ( P ≤ 0.001, r = 0.839) was found between ACA and PCA in the different stages of KCN; the correlation was weaker in eyes with grade 3 ( P ≤ 0.001, r = 0.711) and grade 4 ( P ≤ 0.001, r = 0.717) KCN. The maximum posterior-anterior corneal astigmatism ratio (PCA/ACA, 0.246) was found in patients with stage 1 KCN. Corneal astigmatism in anterior surface was more affected than posterior surface by increasing in the KCN severity, although PCA was more affected than ACA in an early stage of KCN.

Regression of an atlantoaxial rheumatoid pannus following posterior instrumented fusion.

PubMed

Bydon, Mohamad; Macki, Mohamed; Qadi, Mohamud; De la Garza-Ramos, Rafael; Kosztowski, Thomas A; Sciubba, Daniel M; Wolinsky, Jean-Paul; Witham, Timothy F; Gokaslan, Ziya L; Bydon, Ali

2015-10-01

Rheumatoid patients may develop a retrodental lesion (atlantoaxial rheumatoid pannus) that may cause cervical instability and/or neurological compromise. The objective is to characterize clinical and radiographic outcomes after posterior instrumented fusion for atlantoaxial rheumatoid pannus. We retrospectively reviewed all patients who underwent posterior fusions for an atlantoaxial rheumatoid pannus at a single institution. Both preoperative and postoperative imaging was available for all patients. Anterior or circumferential operations, non-atlantoaxial panni, or prior C1-C2 operations were excluded. Primary outcome measures included Nurick score, Ranawat score (neurologic status in patients with rheumatoid arthritis), pannus regression, and reoperation. Pannus volume was determined with axial and sagittal views on both preoperative and postoperative radiological images. Thirty patients surgically managed for an atlantoaxial rheumatoid pannus were followed for a mean of 24.43 months. Nine patients underwent posterior instrumented fusion alone, while 21 patients underwent posterior decompression and instrumented fusion. Following a posterior instrumented fusion in all 30 patients, the pannus statistically significantly regressed by 44.44%, from a mean volume of 1.26cm(3) to 0.70cm(3) (p<0.001), over 8.02 months. The Nurick score significantly improved from 2.40 to 0.60 (p<0.001), but the marginal improvement of 0.20 in the Ranawat score did not reach significance (p=0.312). Six patients (20%) required reoperations over a mean of 13.18 months. Reoperations were indicated for C1 instrumentation failure in four patients and pseudoarthrosis in two patients. Following posterior instrumented fusion, the pannus radiographically regressed by 44.44% over a mean of 8.02 months, and patients clinically improved per the Nurick score. The Ranawat score did not improve, and 20% of patients required reoperation over a mean of 13.18 months. The annualized reoperation rate was

Viscoelastic properties of a spinal posterior dynamic stabilisation device.

PubMed

Lawless, Bernard M; Barnes, Spencer C; Espino, Daniel M; Shepherd, Duncan E T

2016-06-01

The purpose of this study was to quantify the frequency dependent viscoelastic properties of two types of spinal posterior dynamic stabilisation devices. In air at 37°C, the viscoelastic properties of six BDyn 1 level, six BDyn 2 level posterior dynamic stabilisation devices (S14 Implants, Pessac, France) and its elastomeric components (polycarbonate urethane and silicone) were measured using Dynamic Mechanical Analysis. The viscoelastic properties were measured over the frequency range 0.01-30Hz. The BDyn devices and its components were viscoelastic throughout the frequency range tested. The mean storage stiffness and mean loss stiffness of the BDyn 1 level device, BDyn 2 level device, silicone component and polycarbonate urethane component all presented a logarithmic relationship with respect to frequency. The storage stiffness of the BDyn 1 level device ranged from 95.56N/mm to 119.29N/mm, while the BDyn 2 level storage stiffness ranged from 39.41N/mm to 42.82N/mm. BDyn 1 level device and BDyn 2 level device loss stiffness ranged from 10.72N/mm to 23.42N/mm and 4.26N/mm to 9.57N/mm, respectively. No resonant frequencies were recorded for the devices or its components. The elastic property of BDyn 1 level device is influenced by the PCU and silicone components, in the physiological frequency range. The viscoelastic properties calculated in this study may be compared to spinal devices and spinal structures. Copyright © 2016 Elsevier Ltd. All rights reserved.

One-stage posterior focus debridement, interbody grafts, and posterior instrumentation and fusion in the surgical treatment of thoracolumbar spinal tuberculosis with kyphosis in children: a preliminary report.

PubMed

Wang, Yu-Xiang; Zhang, Hong-Qi; Tang, Ming-Xing; Guo, Chao-Feng; Deng, Ang; Wu, Jian-Huang; Liu, Jin-Yang; Deng, Zhansheng; Chen, Jing

2016-08-01

The purpose of this study was to determine the efficacy and feasibility of surgical management of children with thoracolumbar spine tuberculosis with kyphosis by using one-stage posterior focus debridement, interbody grafts, and posterior instrumentation and fusion. From October 2010 to September 2013, 21 children with thoracolumbar spinal tuberculosis accompanied by kyphosis were treated with one-stage posterior decompression, interbody grafts, and posterior instrumentation and fusion. There were 13 males and 8 females, aged from 7 to 13 years old (average age 9.9 years). The mean follow-up was 34 months (range26-48 months). Patients were evaluated before and after surgery in terms of ESR, neurologic status, pain, and kyphotic angle. Spinal tuberculosis was completely cured, and the grafted bones were fused in all 21 patients. There was no recurrent tuberculous infection. ESR got normal within 3 months in all patients. The ASIA neurologic classification improved in all cases. Pain relief was obtained in all patients. The average preoperative kyphosis was 29.7° (range 12-42°) and decreased to 5.5° (range 2-10°), postoperatively. There was no significant loss of the correction at the latest follow-up. Our results show that one-stage posterior decompression, interbody grafts, and posterior instrumentation and fusion were an effective treatment for children with thoracolumbar spinal tuberculosis. It is characterized as minimum surgical trauma, good neurologic recovery, good correction of kyphosis, and prevention of progressive kyphosis.

Impact of posterior communicating artery on basilar artery steno-occlusive disease.

PubMed

Hong, J M; Choi, J Y; Lee, J H; Yong, S W; Bang, O Y; Joo, I S; Huh, K

2009-12-01

Acute brainstem infarction with basilar artery (BA) occlusive disease is the most fatal type of all ischaemic strokes. This report investigates the prognostic impact of the posterior communicating artery (PcoA) and whether its anatomy is a safeguard or not. Consecutive patients who had acute brainstem infarction with at least 50% stenosis of BA upon CT angiography (CTA) were studied. The configuration of PcoA was divided into two groups upon CTA: "textbook" group (invisible PcoA with good P1 and P2 segment) and "fetal-variant of PcoA" group (only visible PcoA with absent P1 segment). Baseline demographics, radiological findings and stroke mechanisms were analysed. A multiple regression analysis was performed to predict clinical outcome at 30 days (modified Rankin disability Scale (mRSmechanism (OR 18.0; 95% CI 3.0 to 107.0) and presence of fetal-variant PcoA (OR 5.1; 95% CI 1.4 to 18.8) were independent predictors for good prognosis and initial NIH stroke scale score (OR 1.24 per one-point increase; 95% CI 1.1 to 1.4) for poor prognosis. Fetal-variant PcoA appears to act as a safeguard against ischaemic insult in acute stroke victims involving the brainstem with BA occlusive disease. This result can be explained by the fact that patients with fetal-variant PcoA have a smaller area of posterior circulation and a possibility of retrograde filling into the upper brainstem through the fetal-variant PcoA.

Isolation of the posterior left atrium for patients with persistent atrial fibrillation: routine adenosine challenge for dormant posterior left atrial conduction improves long-term outcome.

PubMed

McLellan, Alex J A; Prabhu, Sandeep; Voskoboinik, Alex; Wong, Michael C G; Walters, Tomos E; Pathik, Bhupesh; Morris, Gwilym M; Nisbet, Ashley; Lee, Geoffrey; Morton, Joseph B; Kalman, Jonathan M; Kistler, Peter M

2017-12-01

Catheter ablation to achieve posterior left atrial wall (PW) isolation may be performed as an adjunct to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF). We aimed to determine whether routine adenosine challenge for dormant posterior wall conduction improved long-term outcome. A total of 161 patients with persistent AF (mean age 59 ± 9 years, AF duration 6 ± 5 years) underwent catheter ablation involving circumferential PVI followed by PW isolation. Posterior left atrial wall isolation was performed with a roof and inferior wall line with the endpoint of bidirectional block. In 54 patients, adenosine 15 mg was sequentially administered to assess reconnection of the pulmonary veins and PW. Sites of transient reconnection were ablated and adenosine was repeated until no further reconnection was present. Holter monitoring was performed at 6 and 12 months to assess for arrhythmia recurrence. Posterior left atrial wall isolation was successfully achieved in 91% of 161 patients (procedure duration 191 ± 49 min, mean RF time 40 ± 19 min). Adenosine-induced reconnection of the PW was demonstrated in 17%. The single procedure freedom from recurrent atrial arrhythmia was superior in the adenosine challenge group (65%) vs. no adenosine challenge (40%, P < 0.01) at a mean follow-up of 19 ± 8 months. After multiple procedures, there was significantly improved freedom from AF between patients with vs. without adenosine PW challenge (85 vs. 65%, P = 0.01). Posterior left atrial wall isolation in addition to PVI is a readily achievable ablation strategy in patients with persistent AF. Routine adenosine challenge for dormant posterior wall conduction was associated with an improvement in the success of catheter ablation for persistent AF. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

Compartmental Innervation of the Superior Oblique Muscle in Mammals.

PubMed

Le, Alan; Poukens, Vadims; Ying, Howard; Rootman, Daniel; Goldberg, Robert A; Demer, Joseph L

2015-10-01

Intramuscular innervation of mammalian horizontal rectus extraocular muscles (EOMs) is compartmental. We sought evidence of similar compartmental innervation of the superior oblique (SO) muscle. Three fresh bovine orbits and one human orbit were dissected to trace continuity of SO muscle and tendon fibers to the scleral insertions. Whole orbits were also obtained from four humans (two adults, a 17-month-old child, and a 33-week stillborn fetus), two rhesus monkeys, one rabbit, and one cow. Orbits were formalin fixed, embedded whole in paraffin, serially sectioned in the coronal plane at 10-μm thickness, and stained with Masson trichrome. Extraocular muscle fibers and branches of the trochlear nerve (CN4) were traced in serial sections and reconstructed in three dimensions. In the human, the lateral SO belly is in continuity with tendon fibers inserting more posteriorly on the sclera for infraducting mechanical advantage, while the medial belly is continuous with anteriorly inserting fibers having mechanical advantage for incycloduction. Fibers in the monkey superior SO insert more posteriorly on the sclera to favor infraduction, while the inferior portion inserts more anteriorly to favor incycloduction. In all species, CN4 bifurcates prior to penetrating the SO belly. Each branch innervates a nonoverlapping compartment of EOM fibers, consisting of medial and lateral compartments in humans and monkeys, and superior and inferior compartments in cows and rabbits. The SO muscle of humans and other mammals is compartmentally innervated in a manner that could permit separate CN4 branches to selectively influence vertical versus torsional action.

Corneo-scleral contact lenses in an uncommon case of keratoconus with high hyperopia and astigmatism.

PubMed

Porcar, Esteban; Montalt, Juan Carlos; España-Gregori, Enrique; Peris-Martínez, Cristina

2017-10-01

To analyse the visual quality achieved by fitting corneo-scleral contact lenses (CScL) in an uncommon case of bilateral keratoconus, high hyperopia and astigmatism. A 45-year-old man presented for eye examination due to the unsatisfactory quality of his vision wearing soft toric contact lenses. He presented high hyperopia and astigmatism with bilateral keratoconus. He was fitted with CScL to correct his irregular astigmatism and ocular aberrations. A diagnostic trial set was used in the fitting process and he was assessed according to standardised fitting methodology. Visual acuity, corneal topography, biometry and ocular aberrations were evaluated. The follow-up period was 1year. The best spectacle-corrected visual acuity was 20/32 with +8.00/-4.50×30° for the right eye (RE) and 20/25 with +7.75/-2.25×120° for the left eye (LE). After CScL fitting, visual acuity was improved to 20/20 and 20/16 for the RE and LE, respectively. The patient wore these contact lenses an average of 13h a day. The total high order aberrations decreased by approximately 79% in the RE (2.37-0.50μm) and 47% in the LE (1.04-0.55μm) after CScL fitting. Visual quality and wearing time were maintained after 1year wearing CScL. In addition, no adverse ocular effects were found during this period. The present case report describes how the patient had CScL fitted successfully for management of keratoconus with high hyperopia and astigmatism. They provided optimal visual quality, along with prolonged use times and no adverse effects to the cornea. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Robotic posterior retroperitoneal adrenalectomy.

PubMed

Okoh, Alexis Kofi; Yigitbas, Hakan; Berber, Eren

2015-09-01

Since its initial description by Mercan et al. laparoscopic posterior retroperitoneal (PR) adrenalectomy has served as an alternaltive to the transabdominal (TL) approach for the treatment of adrenal pathologies. Robotic adrenal surgery has been reported to improve surgeon ergonomics and facilitate dissection. In patients with bilateral adrenal masses, PR adrenalectomy may be the approach of choice. We herein describe the technique, discuss its limitations and present a critical review of the current literature. © 2015 Wiley Periodicals, Inc.

Functionally dissociated aspects in anterior and posterior electrocortical processing of facial threat.

PubMed

Schutter, Dennis J L G; de Haan, Edward H F; van Honk, Jack

2004-06-01

The angry facial expression is an important socially threatening stimulus argued to have evolved to regulate social hierarchies. In the present study, event-related potentials (ERP) were used to investigate the involvement and temporal dynamics of the frontal and parietal regions in the processing of angry facial expressions. Angry, happy and neutral faces were shown to eighteen healthy right-handed volunteers in a passive viewing task. Stimulus-locked ERPs were recorded from the frontal and parietal scalp sites. The P200, N300 and early contingent negativity variation (eCNV) components of the electric brain potentials were investigated. Analyses revealed statistical significant reductions in P200 amplitudes for the angry facial expression on both frontal and parietal electrode sites. Furthermore, apart from being strongly associated with the anterior P200, the N300 showed to be more negative for the angry facial expression in the anterior regions also. Finally, the eCNV was more pronounced over the parietal sites for the angry facial expressions. The present study demonstrated specific electrocortical correlates underlying the processing of angry facial expressions in the anterior and posterior brain sectors. The P200 is argued to indicate valence tagging by a fast and early detection mechanism. The lowered N300 with an anterior distribution for the angry facial expressions indicates more elaborate evaluation of stimulus relevance. The fact that the P200 and the N300 are highly correlated suggests that they reflect different stages of the same anterior evaluation mechanism. The more pronounced posterior eCNV suggests sustained attention to socially threatening information. Copyright 2004 Elsevier B.V.

Early vitrectomy effective for bilateral combined anterior and posterior persistent fetal vasculature syndrome.

PubMed

Walsh, Mark K; Drenser, Kimberly A; Capone, Antonio; Trese, Michael T

2010-04-01

The purpose of this study was to review our surgical experience with patients with bilateral combined anterior and posterior persistent fetal vasculature syndrome (PFVS). We retrospectively reviewed the charts of all patients seen in our tertiary care pediatric retinal practice from 1988 to 2008 with a potential diagnosis of bilateral PFVS with posterior involvement. Clinical diagnosis required the presence of either bilateral persistent hyaloidal stalk tissue with retinal involvement or bilateral dense retrolental fibrovascular plaques (usually with no posterior view preoperatively) without a family history or genetic testing consistent with Norrie disease or familial exudative vitreoretinopathy. Chart review showed 22 vitrectomized patients with clinical findings consistent with bilateral PFVS with posterior involvement who did not have a family history or genetic testing consistent with Norrie disease or familial exudative vitreoretinopathy. All 22 of these patients with posterior retinal involvement also had anterior findings and thus can be classified as combined anterior and posterior PFVS. Of the 13 patients with visual acuity follow-up data, 9 patients (69%) maintained at least light perception vision in at least 1 eye at last follow-up. Of the 28 operated eyes in 16 patients with follow-up data, 3 eyes (11%) were phthisical at last follow-up. Children with bilateral PFVS with posterior retinal involvement have a dismal visual prognosis if left unoperated. In this relatively large series of a rare condition, we find that vitrectomy with or without lensectomy is beneficial in bilateral combined anterior and posterior PFVS in two regards: maintenance or restoration of vision and avoidance of phthisis bulbi.

A damped oscillator imposes temporal order on posterior gap gene expression in Drosophila.

PubMed

Verd, Berta; Clark, Erik; Wotton, Karl R; Janssens, Hilde; Jiménez-Guri, Eva; Crombach, Anton; Jaeger, Johannes

2018-02-01

Insects determine their body segments in two different ways. Short-germband insects, such as the flour beetle Tribolium castaneum, use a molecular clock to establish segments sequentially. In contrast, long-germband insects, such as the vinegar fly Drosophila melanogaster, determine all segments simultaneously through a hierarchical cascade of gene regulation. Gap genes constitute the first layer of the Drosophila segmentation gene hierarchy, downstream of maternal gradients such as that of Caudal (Cad). We use data-driven mathematical modelling and phase space analysis to show that shifting gap domains in the posterior half of the Drosophila embryo are an emergent property of a robust damped oscillator mechanism, suggesting that the regulatory dynamics underlying long- and short-germband segmentation are much more similar than previously thought. In Tribolium, Cad has been proposed to modulate the frequency of the segmentation oscillator. Surprisingly, our simulations and experiments show that the shift rate of posterior gap domains is independent of maternal Cad levels in Drosophila. Our results suggest a novel evolutionary scenario for the short- to long-germband transition and help explain why this transition occurred convergently multiple times during the radiation of the holometabolan insects.

A damped oscillator imposes temporal order on posterior gap gene expression in Drosophila

PubMed Central

Verd, Berta; Clark, Erik; Wotton, Karl R.; Janssens, Hilde; Jiménez-Guri, Eva; Crombach, Anton

2018-01-01

Insects determine their body segments in two different ways. Short-germband insects, such as the flour beetle Tribolium castaneum, use a molecular clock to establish segments sequentially. In contrast, long-germband insects, such as the vinegar fly Drosophila melanogaster, determine all segments simultaneously through a hierarchical cascade of gene regulation. Gap genes constitute the first layer of the Drosophila segmentation gene hierarchy, downstream of maternal gradients such as that of Caudal (Cad). We use data-driven mathematical modelling and phase space analysis to show that shifting gap domains in the posterior half of the Drosophila embryo are an emergent property of a robust damped oscillator mechanism, suggesting that the regulatory dynamics underlying long- and short-germband segmentation are much more similar than previously thought. In Tribolium, Cad has been proposed to modulate the frequency of the segmentation oscillator. Surprisingly, our simulations and experiments show that the shift rate of posterior gap domains is independent of maternal Cad levels in Drosophila. Our results suggest a novel evolutionary scenario for the short- to long-germband transition and help explain why this transition occurred convergently multiple times during the radiation of the holometabolan insects. PMID:29451884

Visual Dysfunction in Posterior Cortical Atrophy

PubMed Central

Maia da Silva, Mari N.; Millington, Rebecca S.; Bridge, Holly; James-Galton, Merle; Plant, Gordon T.

2017-01-01

Posterior cortical atrophy (PCA) is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions. PMID:28861031

Prehension Movements in a Patient (AC) with Posterior Parietal Cortex Damage and Posterior Callosal Section

ERIC Educational Resources Information Center

Frak, Victor; Paulignan, Yves; Jeannerod, Marc; Michel, Francois; Cohen, Henri

2006-01-01

Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury to the left posterior parietal cortex (PPC) and with a section of the left half of the splenium. The kinematic analysis of AC's grasping movements in direct and perturbed conditions was compared to that of five control subjects. A novel effect in…

Causal evidence for frontal involvement in memory target maintenance by posterior brain areas during distracter interference of visual working memory

PubMed Central

Feredoes, Eva; Heinen, Klaartje; Weiskopf, Nikolaus; Ruff, Christian; Driver, Jon

2011-01-01

Dorsolateral prefrontal cortex (DLPFC) is recruited during visual working memory (WM) when relevant information must be maintained in the presence of distracting information. The mechanism by which DLPFC might ensure successful maintenance of the contents of WM is, however, unclear; it might enhance neural maintenance of memory targets or suppress processing of distracters. To adjudicate between these possibilities, we applied time-locked transcranial magnetic stimulation (TMS) during functional MRI, an approach that permits causal assessment of a stimulated brain region's influence on connected brain regions, and evaluated how this influence may change under different task conditions. Participants performed a visual WM task requiring retention of visual stimuli (faces or houses) across a delay during which visual distracters could be present or absent. When distracters were present, they were always from the opposite stimulus category, so that targets and distracters were represented in distinct posterior cortical areas. We then measured whether DLPFC-TMS, administered in the delay at the time point when distracters could appear, would modulate posterior regions representing memory targets or distracters. We found that DLPFC-TMS influenced posterior areas only when distracters were present and, critically, that this influence consisted of increased activity in regions representing the current memory targets. DLPFC-TMS did not affect regions representing current distracters. These results provide a new line of causal evidence for a top-down DLPFC-based control mechanism that promotes successful maintenance of relevant information in WM in the presence of distraction. PMID:21987824

Surgical approach to posterior inferior cerebellar artery aneurysms.

PubMed

La Pira, Biagia; Sturiale, Carmelo Lucio; Della Pepa, Giuseppe Maria; Albanese, Alessio

2018-02-01

The far-lateral is a standardised approach to clip aneurysms of the posterior inferior cerebellar artery (PICA). Different variants can be adopted to manage aneurysms that differ in morphology, topography, ruptured status, cerebellar swelling and surgeon preference. We distinguished five paradigmatic approaches aimed to manage aneurysms that are: proximal unruptured; proximal ruptured requiring posterior fossa decompression (PFD); proximal ruptured not requiring PFD; distal unruptured; distal ruptured. Preoperative planning in the setting of PICA aneurysm surgery is of paramount importance to perform an effective and safe procedure, to ensure an adequate PFD and optimal proximal control before aneurysm manipulation.

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.

Are Fetal-Type Posterior Cerebral Arteries Associated With an Increased Risk of Posterior Communicating Artery Aneurysms?

PubMed

Thiarawat, Peeraphong; Jahromi, Behnam Rezai; Kozyrev, Danil A; Intarakhao, Patcharin; Teo, Mario K; Choque-Velasquez, Joham; Niemelä, Mika; Hernesniemi, Juha

2018-05-21

Fetal-type posterior cerebral arteries (F-PCAs) might result in alterations in hemodynamic flow patterns and may predispose an individual to an increased risk of posterior communicating artery aneurysms (PCoAAs). To determine the association between PCoAAs and the presence of ipsilateral F-PCAs. We retrospectively reviewed the radiographic findings from 185 patients harboring 199 PCoAAs that were treated at our institution between 2005 and 2015. Our study population consisted of 4 cohorts: (A) patients with 171 internal carotid arteries (ICAs) harboring unilateral PCoAAs; (B) 171 unaffected ICAs in the same patients from the first group; (C) 28 ICAs of 14 patients with bilateral PCoAAs; and (D) 180 ICAs of 90 patients with aneurysms in other locations. We then determined the presence of ipsilateral F-PCAs and recorded all aneurysm characteristics. Group A had the highest prevalence of F-PCAs (42%) compared to 19% in group B, 3% in group C, and 14% in group D (odds ratio A : B = 3.041; A : C = 19.626; and A : D = 4.308; P < .001). PCoAAs were associated with larger diameters of the posterior communicating arteries (median value 1.05 vs 0.86 mm; P = .001). The presence of F-PCAs was associated with larger sizes of the aneurysm necks (median value 3.3 vs 3.0 mm; P = .02). PCoAAs were associated with a higher prevalence of ipsilateral F-PCAs. This variant was associated with larger sizes of the aneurysm necks but was not associated with the sizes of the aneurysm domes or with their rupture statuses.

Epilepsy surgery in the posterior part of the brain.

PubMed

Liava, Alexandra; Mai, Roberto; Cardinale, Francesco; Tassi, Laura; Casaceli, Giuseppe; Gozzo, Francesca; Cossu, Massimo; Nobili, Lino; Castana, Laura; Sartori, Ivana; Lo Russo, Giorgio; Francione, Stefano

2016-11-01

Posterior cortex epilepsy surgery is rarely performed and is associated with a high number of surgical failures, partly because accurate localization of the epileptogenic zone in the posterior part of the brain is extremely difficult. We present the characteristics as well as the surgical outcome and its determinants of a cohort of 208 consecutive patients (adults/children: 125/83) operated on for drug-resistant posterior cortex epilepsy at the "Claudio Munari" Epilepsy Surgery Centre, Milan between May 1996 and May 2013 (mean postsurgical follow-up: 9.6years). In addition, we highlight the differences in anatomoelectroclinical features and outcome between (i) patients who necessitated an invasive preoperative evaluation and those who proceeded directly to surgery and (ii) adults and children. Mean age at epilepsy onset was 6.8years (91.4% with onset before 14years of age). A high seizure frequency was reported by 51% of subjects, interictal and ictal EEG features were localizing in 16% and 28% of cases, and 86% of patients had a positive, judged as more or less informative, MRI. Invasive presurgical evaluation by stereoelectroencephalography was performed in 54% of patients; explorations may schematically be grouped in three main implantation patterns. Globally, 70% of subjects achieved seizure freedom, and further, 10% achieved Engel class II, with the patients operated on in childhood achieving significantly better postsurgical results in terms of seizure freedom and drug discontinuation. Duration of epilepsy represented the most consistent predictor of surgical outcome, with early surgery being correlated with higher chances of surgical success. Therefore, we recommend an early surgical referral in cases of pharmacoresistant posterior cortex seizures. Furthermore, we suggest that surgical failure might be predicted very early, namely within the first 6 postoperative months. We conclude that surgical management of posterior cortex epilepsy may attain excellent

Biomechanical and clinical factors related to stage I posterior tibial tendon dysfunction.

PubMed

Rabbito, Melissa; Pohl, Michael B; Humble, Neil; Ferber, Reed

2011-10-01

Case control. To investigate differences in arch height, ankle muscle strength, and biomechanical factors in individuals with stage I posterior tibial tendon dysfunction (PTTD) in comparison to healthy individuals. PTTD is a progressive condition, so early recognition and treatment are essential to help delay or reverse the progression. However, no previous studies have investigated stage I PTTD, and no single study has measured static anatomical structure, muscle strength, and gait mechanics in this population. Twelve individuals with stage I PTTD and 12 healthy, age- and gender-matched control subjects, who were engaged in running-related activities, participated in this study. Measurements of arch height index, maximum voluntary ankle invertor muscle strength, and 3-dimensional rearfoot and medial longitudinal arch kinematics during walking were obtained. The runners with PTTD demonstrated significantly lower seated arch height index (P = .02) and greater (P = .03) and prolonged (P = .05) peak rearfoot eversion angle during gait, compared to the healthy runners. No differences were found in standing arch height index values (P = .28), arch rigidity index (P = .06), ankle invertor strength (P = .49), or peak medial longitudinal arch values (P = .49) between groups. The increased foot pronation is hypothesized to place greater strain on the posterior tibialis muscle, which may partially explain the progressive nature of this condition.

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.

[Effects of posterior tibial slope on non-contact anterior cruciate ligament rupture and stability of anterior cruciate ligament rupture knee].

PubMed

Yue, De-bo; E, Sen; Wang, Bai-liang; Wang, Wei-guo; Guo, Wan-shou; Zhang, Qi-dong

2013-05-07

To retrospectively explore the correlation between anterior cruciate ligament (ACL)-ruptured knees, stability of ACL-rupture knee and posterior tibial slope (PTS). From January 2008 to October 2012, 150 knees with ACL rupture underwent arthroscopic surgery for ACL reconstruction. A control group was established for subjects undergoing arthroscopic surgery without ACL rupture during the same period. PTS was measured on a digitalized lateral radiograph. Lachman and mechanized pivot shift tests were performed for assessing the stability of knee. There was significant difference (P = 0.007) in PTS angle between the patients with ACL rupture (9.5 ± 2.2 degrees) and the control group (6.6 ± 1.8 degrees). Only among females, increased slope of tibial plateau had effect on the Lachman test. There was a higher positive rate of pivot shift test in patients of increased posterior slope in the ACL rupture group. Increased posterior tibial slope (>6.6) appears to contribute to non-contact ACL injuries in females. And the changes of tibial slope have no effect upon the Lachman test. However, large changes in tibial slope affect pivot shift.

Orthodontic treatment for posterior crossbites.

PubMed

Agostino, Paola; Ugolini, Alessandro; Signori, Alessio; Silvestrini-Biavati, Armando; Harrison, Jayne E; Riley, Philip

2014-08-08

A posterior crossbite occurs when the top back teeth bite inside the bottom back teeth. When it affects one side of the mouth, the lower jaw may have to move to one side to allow the back teeth to meet together. Several treatments have been recommended to correct this problem. Some treatments widen the upper teeth while others are directed at treating the cause of the posterior crossbite (e.g. breathing problems or sucking habits). Most treatments have been used at each stage of dental development. This is an update of a Cochrane review first published in 2001. To assess the effects of orthodontic treatment for posterior crossbites. We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 21 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 1), MEDLINE via OVID (1946 to 21 January 2014), and EMBASE via OVID (1980 to 21 January 2014). We searched the US National Institutes of Health Trials Register and the World Health Organization (WHO) Clinical Trials Registry Platform for ongoing trials. We placed no restrictions on the language or date of publication when searching the electronic databases. Randomised controlled trials (RCTs) of orthodontic treatment for posterior crossbites in children and adults. Two review authors, independently and in duplicate, screened the results of the electronic searches, and extracted data and assessed the risk of bias of the included studies. We attempted to contact the first named authors of the included studies for missing data and for clarification. We used risk ratios (RR) and 95% confidence intervals (CIs) to summarise dichotomous (event) data, and mean differences (MD) with 95% CIs to summarise continuous data. We performed meta-analyses using fixed-effect models (we would have used random-effects models if we had included four or more studies in a meta-analysis) when comparisons and outcomes were sufficiently similar. We

Posterior ankle impingement in athletes: Pathogenesis, imaging features and differential diagnoses.

PubMed

Hayashi, Daichi; Roemer, Frank W; D'Hooghe, Pieter; Guermazi, Ali

2015-11-01

Posterior ankle impingement is a clinical diagnosis which can be seen following a traumatic hyper-plantar flexion event and may lead to painful symptoms in athletes such as female dancers ('en pointe'), football players, javelin throwers and gymnasts. Symptoms of posterior ankle impingement are due to failure to accommodate the reduced interval between the posterosuperior aspect of the talus and tibial plafond during plantar flexion, and can be due to osseous or soft tissue lesions. There are multiple causes of posterior ankle impingement. Most commonly, the structural correlates of impingement relate to post-traumatic synovitis and intra-articular fibrous bands-scar tissue, capsular scarring, or bony prominences. The aims of this pictorial review article is to describe different types of posterior ankle impingement due to traumatic and non-traumatic osseous and soft tissue pathology in athletes, to describe diagnostic imaging strategies of these pathologies, and illustrate their imaging features, including relevant differential diagnoses. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Posterior Urethral Strictures

PubMed Central

Gelman, Joel; Wisenbaugh, Eric S.

2015-01-01

Pelvic fracture urethral injuries are typically partial and more often complete disruptions of the most proximal bulbar and distal membranous urethra. Emergency management includes suprapubic tube placement. Subsequent primary realignment to place a urethral catheter remains a controversial topic, but what is not controversial is that when there is the development of a stricture (which is usually obliterative with a distraction defect) after suprapubic tube placement or urethral catheter removal, the standard of care is delayed urethral reconstruction with excision and primary anastomosis. This paper reviews the management of patients who suffer pelvic fracture urethral injuries and the techniques of preoperative urethral imaging and subsequent posterior urethroplasty. PMID:26691883

An update on surgical approaches in hip arthoplasty: lateral versus posterior approach.

PubMed

Mukka, Sebastian S; Sayed-Noor, Arkan S

2014-10-02

In this update we searched the literature about the outcome of the lateral versus posterior approach in hip arthoplasty for osteoarthritis (OA) and femoral neck fracture (FNF) patients. The available evidence shows that the use of posterior approach in OA patients is associated with lower mortality and better functional outcome while the use of lateral approach in FNF patients gives lower dislocation rate. We recommend therefore the use of posterior approach in OA patients and lateral approach in FNF patients.

Expression Profile of the Integrin Receptor Subunits in the Guinea Pig Sclera.

PubMed

Wang, Kevin K; Metlapally, Ravikanth; Wildsoet, Christine F

2017-06-01

The ocular dimensional changes in myopia reflect increased scleral remodeling, and in high myopia, loss of scleral integrity leads to biomechanical weakening and continued scleral creep. As integrins, a type of cell surface receptors, have been linked to scleral remodeling, they represent potential targets for myopia therapies. As a first step, this study aimed to characterize the integrin subunits at the messenger RNA level in the sclera of the guinea pig, a more recently added but increasingly used animal model for myopia research. Primers for α and β integrin subunits were designed using NCBI/UCSC Genome Browser and Primer3 software tools. Total RNA was extracted from normal scleral tissue and isolated cultured scleral fibroblasts, as well as liver and lung, as reference tissues, all from guinea pig. cDNA was produced by reverse transcription, PCR was used to amplify products of predetermined sizes, and products were sequenced using standard methods. Guinea pig scleral tissue expressed all known integrin alpha subunits except αD and αE. The latter integrin subunits were also not expressed by cultured guinea pig scleral fibroblasts; however, their expression was confirmed in guinea pig liver. In addition, isolated cultured fibroblasts did not express integrin subunits αL, αM, and αX. This difference between results for cultured cells and intact sclera presumably reflects the presence in the latter of additional cell types. Both guinea pig scleral tissue and isolated scleral fibroblasts expressed all known integrin beta subunits. All results were verified through sequencing. The possible contributions of integrins to scleral remodeling make them plausible targets for myopia prevention. Data from this study will help guide future ex vivo and in vitro studies directed at understanding the relationship between scleral integrins and ocular growth regulation in the guinea pig model for myopia.

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.

The molecular logic for planarian regeneration along the anterior-posterior axis.

PubMed

Umesono, Yoshihiko; Tasaki, Junichi; Nishimura, Yui; Hrouda, Martina; Kawaguchi, Eri; Yazawa, Shigenobu; Nishimura, Osamu; Hosoda, Kazutaka; Inoue, Takeshi; Agata, Kiyokazu

2013-08-01

The planarian Dugesia japonica can regenerate a complete individual from a head, trunk or tail fragment via activation of somatic pluripotent stem cells. About a century ago, Thomas Hunt Morgan attempted to explain the extraordinary regenerative ability of planarians by positing two opposing morphogenetic gradients of formative "head stuff" and "tail stuff" along the anterior-posterior axis. However, Morgan's hypothesis remains open to debate. Here we show that extracellular signal-related kinase (ERK) and Wnt/β-catenin signalling pathways establish a solid framework for planarian regeneration. Our data suggest that ERK signalling forms a spatial gradient in the anterior region during regeneration. The fibroblast growth factor receptor-like gene nou-darake (which serves as an output of ERK signalling in the differentiating head) and posteriorly biased β-catenin activity negatively regulate ERK signalling along the anterior-posterior axis in distinct manners, and thereby posteriorize regenerating tissues outside the head region to reconstruct a complete head-to-tail axis. On the basis of this knowledge about D. japonica, we proposed that β-catenin signalling is responsible for the lack of head-regenerative ability of tail fragments in the planarian Phagocata kawakatsui, and our confirmation thereof supports the notion that posterior β-catenin signalling negatively modulates the ERK signalling involved in anteriorization across planarian species. These findings suggest that ERK signalling has a pivotal role in triggering globally dynamic differentiation of stem cells in a head-to-tail sequence through a default program that promotes head tissue specification in the absence of posteriorizing signals. Thus, we have confirmed the broad outline of Morgan's hypothesis, and refined it on the basis of our proposed default property of planarian stem cells.

Pediatric Pontine Cavernous Malformations: The Presigmoid, Posterior Petrosal Approach.

PubMed

Kulwin, Charles G; Payner, Troy D; Nelson, Rick F; Ackerman, Laurie L; Fulkerson, Daniel H

2018-03-03

Brainstem cavernous malformations (cavernomas) in children have a high risk of hemorrhage and neurological deterioration. This risk is magnified if the child has a genetic predisposition for cavernoma formation. The surgical management is challenging and carries a significant risk of morbidity. To describe the feasibility of a posterior petrosal approach to brainstem cavernomas in a pediatric population. A single institution operative experience with this technique was reviewed; 2 cases were identified and are technically described here with supportive figures and illustrations, as well as a focused literature review. Two pediatric cases with multiple symptomatic hemorrhages from large expanding pontine cavernomas were identified. Both cavernomas were resected through a presigmoid posterior petrosal approach. While this approach is well described in the adult literature for ventral brainstem lesions, its description for the treatment of pontine cavernomas in the pediatric populations is scarce. This study demonstrates the utility and feasibility of the posterior petrosal approach in two pediatric patients at different points in cranial base development.

Postpubertal genitourinary function following posterior urethral disruptions in children.

PubMed

Boone, T B; Wilson, W T; Husmann, D A

1992-10-01

A total of 24 boys sustaining a simultaneous pelvic fracture and posterior urethral disruption was observed from the time of injury through puberty. Average length of followup was 6 years. In contrast to the adult, in whom the urethra is invariably injured at the prostatomembranous junction, the posterior urethral disruptions in the prepubertal patient were at 3 distinct locations: 1) supraprostatic in 4 patients, 2) transprostatic in 4 and 3) prostatomembranous in 16. Prolonged followup through puberty in these children revealed that the frequency of complications was significantly higher for urethral injuries proximal to the prostatomembranous region compared to those at this latter site: impotence 75% versus 31%, intractable strictures following repairs 75% versus 12% and urinary incontinence 25% versus 0%. In summary, the prognosis of children who sustain a posterior urethral disruption should be based on the location of the injury and must remain guarded until the individual attains a postpubertal status.

[Diagnostic value of MRI for posterior root tear of medial and lateral meniscus].

PubMed

Qian, Yue-Nan; Liu, Fang; Dong, Yi-Long; Cai, Chun-Yuan

2018-03-25

To explore diagnostic value of MRI on posterior root tear of medial and lateral meniscus. From January 2012 to January 2016, clinical data of 43 patients with meniscal posterior root tear confirmed by arthroscopy were retrospective analyzed, including 25 males and 18 females, aged from 27 to 69 years old with an average age of(42.5±8.3)years old;27 cases on the right side and 16 cases on the left side. MRI examinations of 43 patients with tear of posterior meniscus root confirmed by knee arthroscopies were retrospectively reviewed. MRI images were double-blinded, independently, retrospectively scored by two imaging physicians. Sensitivity, specificity and accuracy of MRI diagnosis of lateral and medial meniscus posterior root tear were calculated, and knee ligament injury and meniscal dislocation were calculated. Forty-three of 143 patients were diagnosed with meniscus posterior root tears by arthroscopy, including 19 patients with lateral tears and 24 patients with medial tears. The sensitivity, specificity and accuracy in diagnosis of posterior medial meniscus root tears for doctor A were 91.67%, 86.6% and 83.9% respectively, and for doctor B were 87.5%, 87.4% and 87.4%, 19 patients with medial meniscal protrusion and 2 patients with anterior cruciate ligament tear. The sensitivity, specificity and accuracy in diagnosis of posterior lateral meniscus root tears for doctor A were 73.7%, 79.9% and 79% respectively, and for doctor B were 78.9%, 82.3% and 82.5%, 4 patients with lateral meniscus herniation and 16 patients with cruciate ligament tear. Kappa statistics for posterior medial meniscus root tears and posterior lateral meniscus root tears were 0.84 and 0.72. MRI could effectively demonstrate imaging features of medial and lateral meniscal root tear and its accompanying signs. It could provide the basis for preoperative diagnosis of clinicians, and be worthy to be popularized. Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.

Posterior consistency in conditional distribution estimation

PubMed Central

Pati, Debdeep; Dunson, David B.; Tokdar, Surya T.

2014-01-01

A wide variety of priors have been proposed for nonparametric Bayesian estimation of conditional distributions, and there is a clear need for theorems providing conditions on the prior for large support, as well as posterior consistency. Estimation of an uncountable collection of conditional distributions across different regions of the predictor space is a challenging problem, which differs in some important ways from density and mean regression estimation problems. Defining various topologies on the space of conditional distributions, we provide sufficient conditions for posterior consistency focusing on a broad class of priors formulated as predictor-dependent mixtures of Gaussian kernels. This theory is illustrated by showing that the conditions are satisfied for a class of generalized stick-breaking process mixtures in which the stick-breaking lengths are monotone, differentiable functions of a continuous stochastic process. We also provide a set of sufficient conditions for the case where stick-breaking lengths are predictor independent, such as those arising from a fixed Dirichlet process prior. PMID:25067858

Management of the failed posterior/multidirectional instability patient.

PubMed

Forsythe, Brian; Ghodadra, Neil; Romeo, Anthony A; Provencher, Matthew T

2010-09-01

Although the results of operative treatment of posterior and multidirectional instability (P-MDI) of the shoulder have improved, they are not as reliable as those treated for anterior instability of the shoulder. This may be attributed to the complexities in the classification, etiology, and physical examination of a patient with suspected posterior and multidirectional instability. Failure to address the primary and concurrent lesion adequately and the development of pain and/or stiffness are contributing factors to the failure of P-MDI procedures. Other pitfalls include errors in history and physical examination, failure to recognize concomitant pathology, and problems with the surgical technique or implant failure. Patulous capsular tissues and glenoid version also play in role management of failed P-MDI patients. With an improved understanding of pertinent clinical complaints and physical examination findings and the advent of arthroscopic techniques and improved implants, successful strategies for the nonoperative and operative management of the patient after a failed posterior or multidirectional instability surgery may be elucidated. This article highlights the common presentation, physical findings, and radiographic workup in a patient that presents after a failed P-MDI repair and offers strategies for revision surgical repair.

Cervical disc hernia operations through posterior laminoforaminotomy

PubMed Central

Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

2016-01-01

Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis. PMID:27217655

Syphilitic posterior placoid chorioretinitis as initial presentation of early neurosyphilis.

PubMed

Molina-Sócola, F E; López-Herrero, F; Medina-Tapia, A; Rueda-Rueda, T; Contreras-Díaz, M; Sánchez-Vicente, J L

2017-10-01

A 36 year-old male with a recent HIV diagnosis, presented with loss of vision of his left eye. Ophthalmoscopy revealed a unilateral yellowish placoid lesion in the macula. After fluorescein angiography, optical coherence tomography, optical coherence tomography angiography, syphilis serology, and cerebrospinal fluid results, he was diagnosed with neurosyphilis and syphilitic posterior placoid chorioretinitis. Acute syphilitic posterior placoid chorioretinitis is a rare ocular manifestation of syphilis. All patients with characteristic clinical and angiographic findings of acute syphilitic posterior placoid chorioretinitis should be tested for a neurosyphilis and human immunodeficiency virus co-infection. Early treatment with intravenous penicillin is usually effective with good visual results. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Gluteo-vaginal fistula after posterior intravaginal slingplasty: a case report.

PubMed

Grynberg, Michael; Teyssedre, Jacques; Staerman, Frederic

2009-07-01

In patients with posthysterectomy prolapse of the vaginal vault, the posterior intravaginal slingplasty (posterior IVS, Tyco Healthcare, USA) has been suggested as an alternative to traditional vaginal vault suspensions. The goal of this technique is to recreate the uterosacral ligaments and to reinforce the rectovaginal fascia with the use of prosthetic material. We report the case of a 53-year-old woman with a history of 27 months of perineal suppurative discharge after she underwent a vaginal vault prolapse and rectocele repair using a posterior IVS (Tyco Healthcare, USA). The IVS tape was reinforced by interposing a rectovaginal monofilament polypropylene mesh (Parietex, Sofradim, France). Imaging studies and surgical exploration confirmed infection of the IVS mesh with the formation of a gluteo-vaginal fistula while the rectovaginal mesh was intact.

Relationship between the posterior cerebral artery and the cisternal segment of the oculomotor nerve.

PubMed

Uz, Aysun; Tekdemir, Ibrahim

2006-12-01

The aim of this study was to evaluate the relationship between the cisternal segment of the oculomotor nerve and the posterior cerebral artery and its branches. The oculomotor nerve and the posterior cerebral artery of 15 cadaver brains (30 hemispheres) were examined using a surgical microscope. The dorsal portion of the cisternal segment of the oculomotor nerve had a close relationship with the P(1) and P(2) segments of the posterior cerebral artery in 100% of cases, the thalamoperforating arteries in 97%, the collicular arteries in 97%, the short circumferential arteries in 33% and the posterior medial choroidal arteries in 20%. The proximal portion of the nerve had a close relationship with the P(1) segment of the posterior cerebral artery, the thalamoperforating arteries, the collicular arteries and the short circumferential arteries, whereas the distal portion had a close relationship with the P(2) segment of the posterior cerebral artery and the posterior medial choroidal arteries. The oculomotor nerve was perforated by various arteries in different portions. These arteries were the thalamoperforating arteries in 10% of the hemispheres, the collicular arteries in 16% and the short circumferential arteries in 11%. It can be concluded that the dorsal portion of the cisternal segment of the oculomotor nerve has a close relationship with the branches arising from the P(1) and P(2) segments of the posterior cerebral artery. These arteries supply the cisternal segment of the oculomotor nerve.

An unusual stress fracture: Bilateral posterior longitudinal stress fracture of tibia.

PubMed

Malkoc, Melih; Korkmaz, Ozgur; Ormeci, Tugrul; Oltulu, Ismail; Isyar, Mehmet; Mahirogulları, Mahir

2014-01-01

Stress fractures (SF) occur when healthy bone is subjected to cyclic loading, which the normal carrying range capacity is exceeded. Usually, stress fractures occur at the metatarsal bones, calcaneus, proximal or distal tibia and tends to be unilateral. This article presents a 58-year-old male patient with bilateral posterior longitudinal tibial stress fractures. A 58 years old male suffering for persistent left calf pain and decreased walking distance for last one month and after imaging studies posterior longitudinal tibial stress fracture was detected on his left tibia. After six months the patient was admitted to our clinic with the same type of complaints in his right leg. All imaging modalities and blood counts were performed and as a result longitudinal posterior tibial stress fractures were detected on his right tibia. Treatment of tibial stress fracture includes rest and modified activity, followed by a graded return to activity commensurate with bony healing. We have applied the same treatment protocol and our results were acceptable but our follow up time short for this reason our study is restricted for separate stress fractures of the posterior tibia. Although the main localization of tibial stress fractures were unilateral, anterior and transverse pattern, rarely, like in our case, the unusual bilateral posterior localization and longitudinal pattern can be seen. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Os tibiale externum or sesamoid in the tendon of tibialis posterior.

PubMed

Bareither, D J; Muehleman, C M; Feldman, N J

1995-01-01

From a total of 165 foot and lower leg cadaveric specimens, 38 specimens were selected by palpation of the region of the tuberosity of the navicular for the possible presence of an accessory bone. Specimens were radiographed and dissected to reveal the presence of an accessory bone and its relationship to the tibialis posterior tendon. Nineteen of the specimens exhibited hypertrophy of the tibialis posterior tendon and 19 specimens exhibited an accessory bone. Specimens exhibiting an accessory bone were divided into two categories. In one group, the accessory bone was located in the tibialis posterior tendon prior to its division and was separated from the tuberosity by at least 3 mm. In the other group, the accessory bone was located in the main segment of the tibialis posterior tendon, connected to the tuberosity of the navicular by fibrous tissue, and, in some cases, exhibited a central cavity between the accessory bone and tuberosity. The accessory bone of specimens in the first group was considered to be a sesamoid in the tibialis posterior tendon and the accessory bone in the second group was an ossicle considered to be the os tibiale externum. Linking the os tibiale externum to the tibiale component of the primitive tetrapod foot rather than to the prehallux component eliminates the use of the term "prehallux" as an alternative name for this ossicle.

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

Radiographic Response to Yttrium-90 Radioembolization in Anterior Versus Posterior Liver Segments

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

Ibrahim, Saad M.; Lewandowski, Robert J.; Ryu, Robert K.

2008-11-15

The purpose of our study was to determine if preferential radiographic tumor response occurs in tumors located in posterior versus anterior liver segments following radioembolization with yttrium-90 glass microspheres. One hundred thirty-seven patients with chemorefractory liver metastases of various primaries were treated with yttrium-90 glass microspheres. Of these, a subset analysis was performed on 89 patients who underwent 101 whole-right-lobe infusions to liver segments V, VI, VII, and VIII. Pre- and posttreatment imaging included either triphasic contrast material-enhanced CT or gadolinium-enhanced MRI. Responses to treatment were compared in anterior versus posterior right lobe lesions using both RECIST and WHO criteria.more » Statistical comparative studies were conducted in 42 patients with both anterior and posterior segment lesions using the paired-sample t-test. Pearson correlation was used to determine the relationship between pretreatment tumor size and posttreatment tumor response. Median administered activity, delivered radiation dose, and treatment volume were 2.3 GBq, 118.2 Gy, and 1,072 cm{sup 3}, respectively. Differences between the pretreatment tumor size of anterior and posterior liver segments were not statistically significant (p = 0.7981). Differences in tumor response between anterior and posterior liver segments were not statistically significant using WHO criteria (p = 0.8557). A statistically significant correlation did not exist between pretreatment tumor size and posttreatment tumor response (r = 0.0554, p = 0.4434). On imaging follow-up using WHO criteria, for anterior and posterior regions of the liver, (1) response rates were 50% (PR = 50%) and 45% (CR = 9%, PR = 36%), and (2) mean changes in tumor size were -41% and -40%. In conclusion, this study did not find evidence of preferential radiographic tumor response in posterior versus anterior liver segments treated with yttrium-90 glass microspheres.« less

Radiographic response to yttrium-90 radioembolization in anterior versus posterior liver segments.

PubMed

Ibrahim, Saad M; Lewandowski, Robert J; Ryu, Robert K; Sato, Kent T; Gates, Vanessa L; Mulcahy, Mary F; Kulik, Laura; Larson, Andrew C; Omary, Reed A; Salem, Riad

2008-01-01

The purpose of our study was to determine if preferential radiographic tumor response occurs in tumors located in posterior versus anterior liver segments following radioembolization with yttrium-90 glass microspheres. One hundred thirty-seven patients with chemorefractory liver metastases of various primaries were treated with yttrium-90 glass microspheres. Of these, a subset analysis was performed on 89 patients who underwent 101 whole-right-lobe infusions to liver segments V, VI, VII, and VIII. Pre- and posttreatment imaging included either triphasic contrast material-enhanced CT or gadolinium-enhanced MRI. Responses to treatment were compared in anterior versus posterior right lobe lesions using both RECIST and WHO criteria. Statistical comparative studies were conducted in 42 patients with both anterior and posterior segment lesions using the paired-sample t-test. Pearson correlation was used to determine the relationship between pretreatment tumor size and posttreatment tumor response. Median administered activity, delivered radiation dose, and treatment volume were 2.3 GBq, 118.2 Gy, and 1,072 cm(3), respectively. Differences between the pretreatment tumor size of anterior and posterior liver segments were not statistically significant (p = 0.7981). Differences in tumor response between anterior and posterior liver segments were not statistically significant using WHO criteria (p = 0.8557). A statistically significant correlation did not exist between pretreatment tumor size and posttreatment tumor response (r = 0.0554, p = 0.4434). On imaging follow-up using WHO criteria, for anterior and posterior regions of the liver, (1) response rates were 50% (PR = 50%) and 45% (CR = 9%, PR = 36%), and (2) mean changes in tumor size were -41% and -40%. In conclusion, this study did not find evidence of preferential radiographic tumor response in posterior versus anterior liver segments treated with yttrium-90 glass microspheres.

The Connective Tissue Components of Optic Nerve Head Cupping in Monkey Experimental Glaucoma Part 1: Global Change

PubMed Central

Yang, Hongli; Ren, Ruojin; Lockwood, Howard; Williams, Galen; Libertiaux, Vincent; Downs, Crawford; Gardiner, Stuart K.; Burgoyne, Claude F.

2015-01-01

Purpose To characterize optic nerve head (ONH) connective tissue change within 21 monkey experimental glaucoma (EG) eyes, so as to identify its principal components. Methods Animals were imaged three to five times at baseline then every 2 weeks following chronic unilateral IOP elevation, and euthanized early through end-stage confocal scanning laser tomographic change. Optic nerve heads were serial-sectioned, three-dimensionally (3D) reconstructed, delineated, and quantified. Overall EG versus control eye differences were assessed by general estimating equations (GEE). Significant, animal-specific, EG eye change was required to exceed the maximum physiologic intereye differences in six healthy animals. Results Overall EG eye change was significant (P < 0.0026) and animal-specific EG eye change most frequent, for five phenomena (number of EG eyes and range of animal-specific change): posterior laminar deformation (21, −29 to −437 μm), laminar thickening (11, 20–73 μm) and thinning (3, −23 to −31 μm), scleral canal expansion (17, 20–139 μm), outward anterior (16, −16 to −124 μm) and posterior (17, −22 to −279 μm) laminar insertion migration, and peripapillary scleral bowing (11, 21–77 μm). Experimental glaucoma versus control eye laminar thickness differences were bimodal in behavior, being thickened in most EG eyes demonstrating the least deformation and less thickened or thinned in most EG eyes demonstrating the greatest deformation. Conclusions Our postmortem studies retrospectively identify five connective tissue components of ONH “cupping” in monkey EG which serve as targets for longitudinally staging and phenotyping ONH connective tissue alteration within all forms of monkey and human optic neuropathy. PMID:26641545

Conduction aphasia as a function of the dominant posterior perisylvian cortex. Report of two cases.

PubMed

Quigg, Mark; Geldmacher, David S; Elias, W Jeff

2006-05-01

Assessment of eloquent functions during brain mapping usually relies on testing reading, speech, and comprehension to uncover transient deficits during electrical stimulation. These tests stem from findings predicted by the Geschwind-Wernicke hypothesis of receptive and expressive cortices connected by white matter tracts. Later work, however, has emphasized cortical mechanisms of language function. The authors report two cases that demonstrate that conduction aphasia is cortically mediated and can be inadequately assessed if not specifically evaluated during brain mapping. To determine the distribution of language on the dominant cortex, electrical cortical stimulation was performed in two cases by using implanted subdural electrodes during brain mapping before epilepsy surgery. A transient isolated deficit in repetition of language was reported during stimulation of the posterior portion of the dominant superior temporal gyrus in one patient and during stimulation of the supramarginal gyrus in the other patient. These cases demonstrate a localization of language repetition to the posterior perisylvian cortex. Brain mapping of this region should include assessment of verbal repetition to avoid potential deficits resembling conduction aphasia.

Complications of correction for focal kyphosis after posterior osteotomy and the corresponding management.

PubMed

Zeng, Yan; Chen, Zhongqiang; Guo, Zhaoqing; Qi, Qiang; Li, Weishi; Sun, Chuiguo

2013-10-01

A clinical retrospective study. To analyze the complications and relevant management of the correction procedure for focal kyphosis. The treatment of focal kyphosis is a difficult problem in spine surgery. The potential complications of surgery should be considered cautiously and managed positively. Eighty-one patients with focal kyphosis were treated by posterior osteotomy and correction. The etiology was posttraumatic in 31 cases, healed tuberculosis in 31 cases, congenital in 17 cases, and iatrogenic in 2 cases. The surgical procedures were pedicle subtraction osteotomy in 19 cases, posterior osteotomy with anterior opening-posterior closing correction in 23 cases, and posterior vertebral column resection with dual axial rotation correction in 39 cases. The intraoperative and postoperative complications were summarized, and the corresponding management was described in detail. The average follow-up time was 31 months. Among patients who underwent pedicle subtraction osteotomy, the intraoperative and postoperative complications included 3 cases of dural tear and 1 case of wound infection. For posterior osteotomy with anterior opening-posterior closing correction, the complications included 4 cases of dural tear, 1 case of wound infection, and 1 case of instrumentation loosening and recurrence of kyphosis . For posterior vertebral column resection with dual axial rotation correction, the complications included 3 cases of dural tear, 5 cases of nerve root injury, 1 case of titanium mesh loosening, 1 case of osteotomy segment migration, 2 cases of transient neurological compromise, and 1 case of instrumentation loosening and kyphosis recurrence. All the complications were treated positively and pertinently. During the posterior osteotomy and correction of focal kyphosis, the risk of surgery increases along with the more severe deformity and the more complicated surgical procedure. However, most complications do not significantly affect the outcome if treated

Posterior cingulate cortex mediates outcome-contingent allocation of behavior

PubMed Central

Hayden, Benjamin Y.; Nair, Amrita C.; McCoy, Allison N.; Platt, Michael L.

2008-01-01

SUMMARY Adaptive decision making requires selecting an action and then monitoring its consequences to improve future decisions. The neuronal mechanisms supporting action evaluation and subsequent behavioral modification, however, remain poorly understood. To investigate the contribution of posterior cingulate cortex (CGp) to these processes, we recorded activity of single neurons in monkeys performing a gambling task in which the reward outcome of each choice strongly influenced subsequent choices. We found that CGp neurons signaled reward outcomes in a nonlinear fashion, and that outcome-contingent modulations in firing rate persisted into subsequent trials. Moreover, firing rate on any one trial predicted switching to the alternative option on the next trial. Finally, microstimulation in CGp following risky choices promoted a preference reversal for the safe option on the following trial. Collectively, these results demonstrate that CGp directly contributes to the evaluative processes that support dynamic changes in decision making in volatile environments. PMID:18940585

Use of fluid-ventilated, gas-permeable scleral lens for management of severe keratoconjunctivitis sicca secondary to chronic graft-versus-host disease

PubMed Central

Takahide, Kikuchi; Parker, Pablo M.; Wu, Michael; Hwang, William Y.K.; Carpenter, Paul A.; Moravec, Carina; Stehr, Barbara; Martin, Paul J.; Rosenthal, Perry; Forman, Stephen J.; Flowers, Mary E.D.

2007-01-01

Keratoconjunctivitis sicca (KCS) occurs in 40-60 % of patients with chronic graft-versus-host-disease (GVHD) after allogeneic hematopoietic cell transplantation. While immunosuppressive therapy is the primary treatment of chronic GVHD, ocular symptoms require measures to improve ocular lubrication, decrease inflammation and maintain mucosal integrity. The liquid corneal bandage provided by a fluid-ventilated, gas-permeable scleral lens (SL) has been effective in mitigating symptoms and resurfacing corneal erosions in patients with KCS related to causes other than chronic GVHD. We report outcomes in 9 consecutive patients referred for SL fitting for chronic GVHD-related severe KCS that was refractory to standard treatments. All patients reported improvement of ocular symptoms and reduced the use of topical lubricants after SL fitting resulting from decrease evaporation. No serious adverse events or infections attributable to the SL occurred. The median Ocular Surface Disease Index improved from 81 (75-100) to 21 (6-52) within 2 weeks after SL fitting and was 12 (2-53) at the time of last contact, 1-23 months (median, 8.0) after SL fitting. Disability related to KCS resolved in 7 patients after SL fitting. The use of SL appears to be safe and effective in patients with severe chronic GVHD-related KCS refractory to conventional therapies. PMID:17697963

Auditory motion-specific mechanisms in the primate brain

PubMed Central

Baumann, Simon; Dheerendra, Pradeep; Joly, Olivier; Hunter, David; Balezeau, Fabien; Sun, Li; Rees, Adrian; Petkov, Christopher I.; Thiele, Alexander; Griffiths, Timothy D.

2017-01-01

This work examined the mechanisms underlying auditory motion processing in the auditory cortex of awake monkeys using functional magnetic resonance imaging (fMRI). We tested to what extent auditory motion analysis can be explained by the linear combination of static spatial mechanisms, spectrotemporal processes, and their interaction. We found that the posterior auditory cortex, including A1 and the surrounding caudal belt and parabelt, is involved in auditory motion analysis. Static spatial and spectrotemporal processes were able to fully explain motion-induced activation in most parts of the auditory cortex, including A1, but not in circumscribed regions of the posterior belt and parabelt cortex. We show that in these regions motion-specific processes contribute to the activation, providing the first demonstration that auditory motion is not simply deduced from changes in static spatial location. These results demonstrate that parallel mechanisms for motion and static spatial analysis coexist within the auditory dorsal stream. PMID:28472038

Sliding mechanics with microscrew implant anchorage.

PubMed

Park, Hyo-Sang; Kwon, Tae-Geon

2004-10-01

Three cases are illustrated. One was treated with maxillary microscrew implants, another with mandibular microscrew implants, and the third with both maxillary and mandibular microscrew implants. With the maxillary microscrew implants, the maxillary anterior teeth were retracted bodily with a slight intrusion and all the premolar extraction space was closed without loss of anchorage. Furthermore, the maxillary posterior teeth showed distal movement. The mandibular microscrew implants controlled the vertical position of the mandibular posterior teeth and played an important role in improving the facial profile. The efficacy of sliding mechanics with microscrew implant anchorage on the treatment of skeletal Class II malocclusion is also discussed.

Prevalence of posterior elbow problems in Japanese high school baseball players.

PubMed

Kida, Yoshikazu; Morihara, Toru; Furukawa, Ryuhei; Sukenari, Tsuyoshi; Kotoura, Yoshihiro; Yoshioka, Naoki; Hojo, Tatsuya; Oda, Ryo; Arai, Yuji; Sawada, Koshiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu

2016-09-01

Various posterior elbow problems cause posterior elbow pain among baseball players. We aimed to determine the prevalence and diagnoses associated with posterior elbow problems and post-treatment recovery time for returning to sports in Japanese high school baseball players when treated in the off-season. A total of 576 Japanese high school baseball players who participated in baseball skill training camp during the off-season were enrolled in the study. The elbow of each player's throwing arm was assessed by use of a questionnaire and physical examination. Players with abnormal results were advised to visit the hospital. Players who visited the hospital were initially treated conservatively and underwent surgery if necessary. Retrospectively, players with positive physical examination results associated with posterior elbow pain, defined as olecranon tenderness and/or a positive elbow extension impingement test, were selected. Information about their position, elbow pain, physical examination results, diagnosis, treatment, and recovery time before returning to playing sports was assessed. Olecranon tenderness and/or positive elbow extension impingement test results were found in 76 players (13.2%). Of these, 33 agreed to visit the hospital for further diagnostic imaging and 25 players (75.8%) were diagnosed with posteromedial elbow impingement. By the next spring, 87.9% of players returned to sport, and 100% of players returned to sport before the next summer. The average recovery period was 77 ± 47 days. Physical examinations related to posterior elbow injuries were positive in 13.2% of high school baseball players. The most common diagnosis for posterior elbow pain was posteromedial elbow impingement. All players returned to competitive sports activity levels within 77 ± 47 days. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Exact posterior computation in non-conjugate Gaussian location-scale parameters models

NASA Astrophysics Data System (ADS)

Andrade, J. A. A.; Rathie, P. N.

2017-12-01

In Bayesian analysis the class of conjugate models allows to obtain exact posterior distributions, however this class quite restrictive in the sense that it involves only a few distributions. In fact, most of the practical applications involves non-conjugate models, thus approximate methods, such as the MCMC algorithms, are required. Although these methods can deal with quite complex structures, some practical problems can make their applications quite time demanding, for example, when we use heavy-tailed distributions, convergence may be difficult, also the Metropolis-Hastings algorithm can become very slow, in addition to the extra work inevitably required on choosing efficient candidate generator distributions. In this work, we draw attention to the special functions as a tools for Bayesian computation, we propose an alternative method for obtaining the posterior distribution in Gaussian non-conjugate models in an exact form. We use complex integration methods based on the H-function in order to obtain the posterior distribution and some of its posterior quantities in an explicit computable form. Two examples are provided in order to illustrate the theory.

Molecular signaling along the anterior–posterior axis of early palate development

PubMed Central

Smith, Tara M.; Lozanoff, Scott; Iyyanar, Paul P.; Nazarali, Adil J.

2013-01-01

Cleft palate is a common congenital birth defect in humans. In mammals, the palatal tissue can be distinguished into anterior bony hard palate and posterior muscular soft palate that have specialized functions in occlusion, speech or swallowing. Regulation of palate development appears to be the result of distinct signaling and genetic networks in the anterior and posterior regions of the palate. Development and maintenance of expression of these region-specific genes is crucial for normal palate development. Numerous transcription factors and signaling pathways are now recognized as either anterior- (e.g., Msx1, Bmp4, Bmp2, Shh, Spry2, Fgf10, Fgf7, and Shox2) or posterior-specific (e.g., Meox2, Tbx22, and Barx1). Localized expression and function clearly highlight the importance of regional patterning and differentiation within the palate at the molecular level. Here, we review how these molecular pathways and networks regulate the anterior–posterior patterning and development of secondary palate. We hypothesize that the anterior palate acts as a signaling center in setting up development of the secondary palate. PMID:23316168

Use of Pedicled Trapezius Myocutaneous Flap for Posterior Skull Reconstruction.

PubMed

Singh, Mansher; Rios Diaz, Arturo J; Cauley, Ryan; Smith, Timothy R; Caterson, E J

2015-09-01

Soft-tissue defects in posterior skull can be challenging for reconstruction. If related to tumor resection, these wound beds are generally irradiated and can be difficult from a recipient-vessel perspective for a free tissue transfer. Locoregional flaps might prove to be important reconstructive option in such patients. There is a very limited data on the usage of pedicled trapezius myocutaneous flaps for such defects. The authors reviewed existing study for usage of trapezius flap for posterior skull repair and used pedicled trapezius myocutaneous flaps based on the descending branch of superficial cervical artery (SCA) for reconstruction of posterior skull soft-tissue defect in an irradiated and infected wound. Two patients were operated for trapezius myocutaneous flap for posterior skull defects complicated by cerebrospinal fluid (CSF) leakage and epidural abscess. There was no recipient or donor-site complication at a mean follow-up of 12.5 months. Neither of the 2 patients had any functional deficits for the entire duration of the follow-up. Although this flap was able to help in controlling the CSF leakage in the first patient, it successfully healed the cavity generated from epidural abscess drainage in the second patient. The large angle of rotation coupled with the ability to complete the procedure without repositioning the patients makes trapezius myocutaneous flap an attractive option for posterior skull reconstruction. In our limited experience, the pedicled trapezius flaps are a reliable alternative as they are well vascularized and able to obliterate the soft-tissue defect completely. The recipient site healed completely in infected as well as irradiated wound beds. In addition, the donor site can be primarily closed with minimal donor-associated complication.