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Sample records for adjacent-level spinal kinematics

  1. Effect of Device Rigidity and Physiological Loading on Spinal Kinematics after Dynamic Stabilization : An In-Vitro Biomechanical Study

    PubMed Central

    Chun, Kwonsoo; Yang, Inchul; Kim, Namhoon

    2015-01-01

    Objective To investigate the effects of posterior implant rigidity on spinal kinematics at adjacent levels by utilizing a cadaveric spine model with simulated physiological loading. Methods Five human lumbar spinal specimens (L3 to S1) were obtained and checked for abnormalities. The fresh specimens were stripped of muscle tissue, with care taken to preserve the spinal ligaments and facet joints. Pedicle screws were implanted in the L4 and L5 vertebrae of each specimen. Specimens were tested under 0 N and 400 N axial loading. Five different posterior rods of various elastic moduli (intact, rubber, low-density polyethylene, aluminum, and titanium) were tested. Segmental range of motion (ROM), center of rotation (COR) and intervertebral disc pressure were investigated. Results As the rigidity of the posterior rods increased, both the segmental ROM and disc pressure at L4-5 decreased, while those values increased at adjacent levels. Implant stiffness saturation was evident, as the ROM and disc pressure were only marginally increased beyond an implant stiffness of aluminum. Since the disc pressures of adjacent levels were increased by the axial loading, it was shown that the rigidity of the implants influenced the load sharing between the implant and the spinal column. The segmental CORs at the adjacent disc levels translated anteriorly and inferiorly as rigidity of the device increased. Conclusion These biomechanical findings indicate that the rigidity of the dynamic stabilization implant and physiological loading play significant roles on spinal kinematics at adjacent disc levels, and will aid in further device development. PMID:26713140

  2. Adjacent-Level Hypermobility and Instrumented-Level Fatigue Loosening With Titanium and PEEK Rods for a Pedicle Screw System: An In Vitro Study.

    PubMed

    Agarwal, Aakas; Ingels, Marcel; Kodigudla, Manoj; Momeni, Narjes; Goel, Vijay; Agarwal, Anand K

    2016-05-01

    Adjacent-level disease is a common iatrogenic complication seen among patients undergoing spinal fusion for low back pain. This is attributed to the postsurgical differences in stiffness between the spinal levels, which result in abnormal forces, stress shielding, and hypermobility at the adjacent levels. In addition, as most patients undergoing these surgeries are osteoporotic, screw loosening at the index level is a complication that commonly accompanies adjacent-level disease. Recent studies indicate that a rod with lower rigidity than that of titanium may help to overcome these detrimental effects at the adjacent level. The present study was conducted in vitro using 12 L1-S1 specimens divided into groups of six, with each group instrumented with either titanium rods or PEEK (polyetheretherketone) rods. The test protocol included subjecting intact specimens to pure moments of 10 Nm in extension and flexion using an FS20 Biomechanical Spine Test System (Applied Test Systems) followed by hybrid moments on the instrumented specimens to achieve the same L1-S1 motion as that of the intact specimens. During the protocol's later phase, the L4-L5 units from each specimen were segmented for cyclic loading followed by postfatigue kinematic analysis to highlight the differences in motion pre- and postfatigue. The objectives included the in vitro comparison of (1) the adjacent-level motion before and after instrumentation with PEEK and titanium rods and (2) the pre- and postfatigue motion at the instrumented level with PEEK and titanium rods. The results showed that the adjacent levels above the instrumentation caused increased flexion and extension with both PEEK and titanium rods. The postfatigue kinematic data showed that the motion at the instrumented level (L4-L5) increased significantly in both flexion and extension compared to prefatigue motion in titanium groups. However, there was no significant difference in motion between the pre- and postfatigue data in the PEEK

  3. Multisegment Kinematics of the Spinal Column: Soft Tissue Artifacts Assessment.

    PubMed

    Mahallati, Sara; Rouhani, Hossein; Preuss, Richard; Masani, Kei; Popovic, Milos R

    2016-07-01

    A major challenge in the assessment of intersegmental spinal column angles during trunk motion is the inherent error in recording the movement of bony anatomical landmarks caused by soft tissue artifacts (STAs). This study aims to perform an uncertainty analysis and estimate the typical errors induced by STA into the intersegmental angles of a multisegment spinal column model during trunk bending in different directions by modeling the relative displacement between skin-mounted markers and actual bony landmarks during trunk bending. First, we modeled the maximum displacement of markers relative to the bony landmarks with a multivariate Gaussian distribution. In order to estimate the distribution parameters, we measured these relative displacements on five subjects at maximum trunk bending posture. Then, in order to model the error depending on trunk bending angle, we assumed that the error grows linearly as a function of the bending angle. Second, we applied our error model to the trunk motion measurement of 11 subjects to estimate the corrected trajectories of the bony landmarks and investigate the errors induced into the intersegmental angles of a multisegment spinal column model. For this purpose, the trunk was modeled as a seven-segment rigid-body system described using 23 reflective markers placed on various bony landmarks of the spinal column. Eleven seated subjects performed trunk bending in five directions and the three-dimensional (3D) intersegmental angles during trunk bending were calculated before and after error correction. While STA minimally affected the intersegmental angles in the sagittal plane (<16%), it considerably corrupted the intersegmental angles in the coronal (error ranged from 59% to 551%) and transverse (up to 161%) planes. Therefore, we recommend using the proposed error suppression technique for STA-induced error compensation as a tool to achieve more accurate spinal column kinematics measurements. Particularly, for intersegmental

  4. Upper limb kinematics after cervical spinal cord injury: a review.

    PubMed

    Mateo, Sébastien; Roby-Brami, Agnès; Reilly, Karen T; Rossetti, Yves; Collet, Christian; Rode, Gilles

    2015-01-01

    Although a number of upper limb kinematic studies have been conducted, no review actually addresses the key-features of open-chain upper limb movements after cervical spinal cord injury (SCI). The aim of this literature review is to provide a clear understanding of motor control and kinematic changes during open-chain upper limb reaching, reach-to-grasp, overhead movements, and fast elbow flexion movements after tetraplegia. Using data from MEDLINE between 1966 and December 2014, we examined temporal and spatial kinematic measures and when available electromyographic recordings. We included fifteen control case and three series case studies with a total of 164 SCI participants and 131 healthy control participants. SCI participants efficiently performed a broad range of tasks with their upper limb and movements were planned and executed with strong kinematic invariants like movement endpoint accuracy and minimal cost. Our review revealed that elbow extension without triceps brachii relies on increased scapulothoracic and glenohumeral movements providing a dynamic coupling between shoulder and elbow. Furthermore, contrary to normal grasping patterns where grasping is prepared during the transport phase, reaching and grasping are performed successively after SCI. The prolonged transport phase ensures correct hand placement while the grasping relies on wrist extension eliciting either whole hand or lateral grip. One of the main kinematic characteristics observed after tetraplegia is motor slowing attested by increased movement time. This could be caused by (i) decreased strength, (ii) triceps brachii paralysis which disrupts normal agonist-antagonist co-contractions, (iii) accuracy preservation at movement endpoint, and/or (iv) grasping relying on tenodesis. Another feature is a reduction of maximal superior reaching during overhead movements which could be caused by i) strength deficit in agonist muscles like pectoralis major, ii) strength deficit in proximal synergic

  5. Kinematic study of locomotor recovery after spinal cord clip compression injury in rats.

    PubMed

    Alluin, Olivier; Karimi-Abdolrezaee, Soheila; Delivet-Mongrain, Hugo; Leblond, Hugues; Fehlings, Michael G; Rossignol, Serge

    2011-09-01

    After spinal cord injury (SCI), precise assessment of motor recovery is essential to evaluate the outcome of new therapeutic approaches. Very little is known on the recovery of kinematic parameters after clinically-relevant severe compressive/contusive incomplete spinal cord lesions in experimental animal models. In the present study we evaluated the time-course of kinematic parameters during a 6-week period in rats walking on a treadmill after a severe thoracic clip compression SCI. The effect of daily treadmill training was also assessed. During the recovery period, a significant amount of spontaneous locomotor recovery occurred in 80% of the rats with a return of well-defined locomotor hindlimb pattern, regular plantar stepping, toe clearance and homologous hindlimb coupling. However, substantial residual abnormalities persisted up to 6 weeks after SCI including postural deficits, a bias of the hindlimb locomotor cycle toward the back of the animals with overextension at the swing/stance transition, loss of lateral balance and impairment of weight bearing. Although rats never recovered the antero-posterior (i.e. homolateral) coupling, different levels of decoupling between the fore and hindlimbs were measured. We also showed that treadmill training increased the swing duration variability during locomotion suggesting an activity-dependent compensatory mechanism of the motor control system. However, no effect of training was observed on the main locomotor parameters probably due to a ceiling effect of self-training in the cage. These findings constitute a kinematic baseline of locomotor recovery after clinically relevant SCI in rats and should be taken into account when evaluating various therapeutic strategies aimed at improving locomotor function. PMID:21770755

  6. Quantitative analysis of hindlimbs locomotion kinematics in spinalized rats treated with Tamoxifen plus treadmill exercise.

    PubMed

    Osuna-Carrasco, L P; López-Ruiz, J R; Mendizabal-Ruiz, E G; De la Torre-Valdovinos, B; Bañuelos-Pineda, J; Jiménez-Estrada, I; Dueñas-Jiménez, S H

    2016-10-01

    Locomotion recovery after a spinal cord injury (SCI) includes axon regeneration, myelin preservation and increased plasticity in propriospinal and descending spinal circuitries. The combined effects of tamoxifen and exercise after a SCI were analyzed in this study to determine whether the combination of both treatments induces the best outcome in locomotion recovery. In this study, the penetrating injury was provoked by a sharp projectile that penetrates through right dorsal and ventral portions of the T13-L1 spinal segments, affecting propriospinal and descending/ascending tracts. Intraperitoneal application of Tamoxifen and a treadmill exercise protocol, as rehabilitation therapies, separately or combined, were used. To evaluate the functional recovery, angular patterns of the hip, knee and ankle joints as well as the leg pendulum-like movement (PLM) were measured during the unrestricted gait of treated and untreated (UT) animals, previously and after the traumatic injury (15 and 30days post-injury (dpi)). A pattern (curve) comparison analysis was made by using a locally designed Matlab script that determines the Frechet dissimilarity. The SCI magnitude was assessed by qualitative and quantitative histological analysis of the injury site 30days after SCI. Our results showed that all treated groups had an improvement in hindlimbs kinematics compared to the UT group, which showed a poor gait locomotion recovery throughout the rehabilitation period. The group with the combined treatment (tamoxifen+exercise (TE)) presented the best outcome. In conclusion, tamoxifen and treadmill exercise treatments are complementary therapies for the functional recovery of gait locomotion in hemi-spinalized rats. PMID:27450566

  7. Preventing Proximal Adjacent Level Kyphosis With Strap Stabilization.

    PubMed

    Zaghloul, Khaled M; Matoian, Brett J; Denardin, Nicholas B; Patel, Vikas V

    2016-07-01

    A substantial proportion of patients develop proximal junctional kyphosis following spinal surgery. To combat this postoperative change, several techniques have focused on maintaining the structural integrity of adjacent spinal levels and adapting the proximal end of the fusion construct to accommodate the increased mechanical stressors produced by long spinal fusion. The use of Mersilene tape (Ethicon, Somerville, New Jersey) for spine and orthopedic surgery is well documented, although considerably less is known about its use for preventing proximal junctional kyphosis. This article describes a proposed technique using Mersilene tape to provide a check-rein strap stabilization at the proximal end of fusion constructs. Initial data suggest that use of this technique may prevent formation of proximal junctional kyphosis. [Orthopedics. 2016; 39(4):e794-e799.]. PMID:27158827

  8. Multi-segment analysis of spinal kinematics during sit-to-stand in patients with chronic low back pain.

    PubMed

    Christe, Guillaume; Redhead, Lucy; Legrand, Thomas; Jolles, Brigitte M; Favre, Julien

    2016-07-01

    While alterations in spinal kinematics have been frequently reported in patients with chronic low back pain (CLBP), a better characterization of the kinematics during functional activities is needed to improve our understanding and therapeutic solutions for this condition. Recent studies on healthy subjects showed the value of analyzing the spine during sit-to-stand transition (STST) using multi-segment models, suggesting that additional knowledge could be gained by conducting similar assessments in CLBP patients. The objectives of this study were to characterize three dimensional kinematics at the lower lumbar (LLS), upper lumbar (ULS), lower thoracic (LTS) and upper thoracic (UTS) joints during STST, and to test the hypothesis that CLBP patients perform this movement with smaller angle and angular velocity compared to asymptomatic controls. Ten CLBP patients (with minimal to moderate disability) and 11 asymptomatic controls with comparable demographics (52% male, 37.4±5.6 years old, 22.5±2.8kg/m(2)) were tested using a three-dimensional camera-based system following previously proposed protocols. Characteristic patterns of movement were identified at the LLS, ULS and UTS joints in the sagittal plane only. Significant differences in the form of smaller sagittal-plane angle and smaller angular velocity in the patient group compared to the control group were observed at these three joints. This indicated a more rigid spine in the patient group and suggested that CLBP rehabilitation could potentially be enhanced by targeting movement deficits in functional activities. The results further recommended the analysis of STST kinematics using a pelvis-lumbar-thoracic model including lower and upper lumbar and thoracic segments. PMID:27262182

  9. Spinal Kinematics of Adolescent Male Rowers with Back Pain in Comparison with Matched Controls During Ergometer Rowing.

    PubMed

    Ng, Leo; Campbell, Amity; Burnett, Angus; Smith, Anne; O'Sullivan, Peter

    2015-12-01

    There is a high prevalence of low back pain (LBP) in adolescent male rowers. In this study, regional lumbar spinal kinematics and self-reported LBP intensity were compared between 10 adolescent rowers with moderate levels of LBP relating to rowing with 10 reporting no history of LBP during a 15-minute ergometer trial using an electromagnetic tracking system. Adolescent male rowers with LBP reported increasing pain intensity during ergometer rowing. No significant differences were detected in mean upper or lower lumbar angles between rowers with and without LBP. However, compared with rowers without pain, rowers with pain: (1) had relatively less excursion of the upper lumbar spine into extension over the drive phase, (2) had relatively less excursion of the lower lumbar spine into extension over time, (3) had greater variability in upper and lower lumbar angles over the 15-minute ergometer trial, (4) positioned their upper lumbar spine closer to end range flexion for a greater proportion of the drive phase, and (5) showed increased time in sustained flexion loading in the upper lumbar spine. Differences in regional lumbar kinematics exist between adolescent male rowers with and without LBP, which may have injury implication and intervention strategies. PMID:26252195

  10. Assessment of the relationship between box weight and trunk kinematics: does a reduction in box weight necessarily correspond to a decrease in spinal loading?

    PubMed

    Davis, K G; Marras, W S

    2000-01-01

    Typically, the simplest and most cost-efficient ergonomic solution to offset the rising costs of low back injuries is to reduce the box weight that is lifted. However, there is limited research on how a worker interacts with the box. In the present study, we quantify the utility of reducing the weight that is lifted - specifically, how changes in the box weight affect trunk kinematics, trunk moments, and ultimately, spinal loads. In the experiment, 15 participants lifted a variety of box weights (from 9.1 to 41.7 kg) from knee height, carried it a distance of 5 feet (1.5 m), and placed it on a shelf at elbow height. For the lower weights, small increases in box weight (3-9 kg) were offset by the trunk dynamics (sagittal velocity), resulting in no difference in spinal loads. At the same time, spinal loads were found to be significantly higher for weights above 25 kg. Thus, when making ergonomic changes (reduction of box weight), it is important to consider how workers will interact with the box. These results indicate that purely weight-based ergonomic controls might not sufficiently reduce the risk of low back disorders. Furthermore, this study provides additional evidence of the utility of using more complex spinal load models (dynamic, multiple muscle models) when evaluating highly dynamic and complex tasks. PMID:11022880

  11. Examination of the Combined Effects of Chondroitinase ABC, Growth Factors and Locomotor Training following Compressive Spinal Cord Injury on Neuroanatomical Plasticity and Kinematics

    PubMed Central

    Alluin, Olivier; Fehlings, Michael G.; Rossignol, Serge; Karimi-Abdolrezaee, Soheila

    2014-01-01

    While several cellular and pharmacological treatments have been evaluated following spinal cord injury (SCI) in animal models, it is increasingly recognized that approaches to address the glial scar, including the use of chondroitinase ABC (ChABC), can facilitate neuroanatomical plasticity. Moreover, increasing evidence suggests that combinatorial strategies are key to unlocking the plasticity that is enabled by ChABC. Given this, we evaluated the anatomical and functional consequences of ChABC in a combinatorial approach that also included growth factor (EGF, FGF2 and PDGF-AA) treatments and daily treadmill training on the recovery of hindlimb locomotion in rats with mid thoracic clip compression SCI. Using quantitative neuroanatomical and kinematic assessments, we demonstrate that the combined therapy significantly enhanced the neuroanatomical plasticity of major descending spinal tracts such as corticospinal and serotonergic-spinal pathways. Additionally, the pharmacological treatment attenuated chronic astrogliosis and inflammation at and adjacent to the lesion with the modest synergistic effects of treadmill training. We also observed a trend for earlier recovery of locomotion accompanied by an improvement of the overall angular excursions in rats treated with ChABC and growth factors in the first 4 weeks after SCI. At the end of the 7-week recovery period, rats from all groups exhibited an impressive spontaneous recovery of the kinematic parameters during locomotion on treadmill. However, although the combinatorial treatment led to clear chronic neuroanatomical plasticity, these structural changes did not translate to an additional long-term improvement of locomotor parameters studied including hindlimb-forelimb coupling. These findings demonstrate the beneficial effects of combined ChABC, growth factors and locomotor training on the plasticity of the injured spinal cord and the potential to induce earlier neurobehavioral recovery. However, additional

  12. Examination of the combined effects of chondroitinase ABC, growth factors and locomotor training following compressive spinal cord injury on neuroanatomical plasticity and kinematics.

    PubMed

    Alluin, Olivier; Delivet-Mongrain, Hugo; Gauthier, Marie-Krystel; Fehlings, Michael G; Rossignol, Serge; Karimi-Abdolrezaee, Soheila

    2014-01-01

    While several cellular and pharmacological treatments have been evaluated following spinal cord injury (SCI) in animal models, it is increasingly recognized that approaches to address the glial scar, including the use of chondroitinase ABC (ChABC), can facilitate neuroanatomical plasticity. Moreover, increasing evidence suggests that combinatorial strategies are key to unlocking the plasticity that is enabled by ChABC. Given this, we evaluated the anatomical and functional consequences of ChABC in a combinatorial approach that also included growth factor (EGF, FGF2 and PDGF-AA) treatments and daily treadmill training on the recovery of hindlimb locomotion in rats with mid thoracic clip compression SCI. Using quantitative neuroanatomical and kinematic assessments, we demonstrate that the combined therapy significantly enhanced the neuroanatomical plasticity of major descending spinal tracts such as corticospinal and serotonergic-spinal pathways. Additionally, the pharmacological treatment attenuated chronic astrogliosis and inflammation at and adjacent to the lesion with the modest synergistic effects of treadmill training. We also observed a trend for earlier recovery of locomotion accompanied by an improvement of the overall angular excursions in rats treated with ChABC and growth factors in the first 4 weeks after SCI. At the end of the 7-week recovery period, rats from all groups exhibited an impressive spontaneous recovery of the kinematic parameters during locomotion on treadmill. However, although the combinatorial treatment led to clear chronic neuroanatomical plasticity, these structural changes did not translate to an additional long-term improvement of locomotor parameters studied including hindlimb-forelimb coupling. These findings demonstrate the beneficial effects of combined ChABC, growth factors and locomotor training on the plasticity of the injured spinal cord and the potential to induce earlier neurobehavioral recovery. However, additional

  13. Kinematic analysis of the gait of adult sheep during treadmill locomotion: Parameter values, allowable total error, and potential for use in evaluating spinal cord injury.

    PubMed

    Safayi, Sina; Jeffery, Nick D; Shivapour, Sara K; Zamanighomi, Mahdi; Zylstra, Tyler J; Bratsch-Prince, Joshua; Wilson, Saul; Reddy, Chandan G; Fredericks, Douglas C; Gillies, George T; Howard, Matthew A

    2015-11-15

    We are developing a novel intradural spinal cord (SC) stimulator designed to improve the treatment of intractable pain and the sequelae of SC injury. In-vivo ovine models of neuropathic pain and moderate SC injury are being implemented for pre-clinical evaluations of this device, to be carried out via gait analysis before and after induction of the relevant condition. We extend previous studies on other quadrupeds to extract the three-dimensional kinematics of the limbs over the gait cycle of sheep walking on a treadmill. Quantitative measures of thoracic and pelvic limb movements were obtained from 17 animals. We calculated the total-error values to define the analytical performance of our motion capture system for these kinematic variables. The post- vs. pre-injury time delay between contralateral thoracic and pelvic-limb steps for normal and SC-injured sheep increased by ~24s over 100 steps. The pelvic limb hoof velocity during swing phase decreased, while range of pelvic hoof elevation and distance between lateral pelvic hoof placements increased after SC injury. The kinematics measures in a single SC-injured sheep can be objectively defined as changed from the corresponding pre-injury values, implying utility of this method to assess new neuromodulation strategies for specific deficits exhibited by an individual. PMID:26341152

  14. Stress Reduction in Adjacent Level Discs via Dynamic Instrumentation: A Finite Element Analysis

    PubMed Central

    Castellvi, Antonio E.; Huang, Hao; Vestgaarden, Tov; Saigal, Sunil; Pienkowski, David

    2007-01-01

    Background Conventional (rigid) fusion instrumentation is believed to accelerate the degeneration of adjacent discs by increasing stresses caused by motion discontinuity. Fusion instrumentation that employs reduced rod stiffness and increased axial motion, or dynamic instrumentation, may partially alleviate this problem, but the effects of this instrumentation on the stresses in the adjacent disc are unknown. We used a finiteelement model to calculate and compare the stresses in the adjacent-level disc that are induced by rigid and dynamic posterior lumbar fusion instrumentation. Methods A 3-dimensional finite-element model of the lumbar spine was obtained that simulated flexion and extension. The L5–S1 segment of this model was fused, and the L4–L5 segment was fixed with rigid or dynamic instrumentation. The mechanical properties of the dynamic instrumentation were determined by laboratory testing and then used in the finite-element model. Peak stresses in the lumbar discs were calculated and compared. Results The reduced-stiffness component of the dynamic instrumentation was associated with a 1% to 2% reduction in peak compressive stresses in the adjacent-level disc (at 45° flexion), and the increased axial motion component of this instrumentation reduced peak disc stress by 8% to 9%. Areas of disc tissue exposed to 80% of peak stresses of 6.17 MPa were 47% less for discs adjacent to dynamic instrumentation than for those adjacent to rigid instrumentation. Conclusions Reduced stiffness and increased axial motion of dynamic posterior lumbar fusion instrumentation designs result in an approximately 10% cumulative stress reduction for each flexion cycle. The effect of this stress reduction over many cycles may be substantial. Clinical Relevance The cumulative effect of this reduced amplitude and distribution of peak stresses in the adjacent disc may partially alleviate the problem of adjacent-level disc degeneration. PMID:25802582

  15. Trunk and Shoulder Kinematic and Kinetic and Electromyographic Adaptations to Slope Increase during Motorized Treadmill Propulsion among Manual Wheelchair Users with a Spinal Cord Injury

    PubMed Central

    Champagne, Audrey

    2015-01-01

    The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC) propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°). Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG) of the pectoralis major (clavicular and sternal portions) and deltoid (anterior and posterior fibers) was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments. PMID:25793200

  16. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: an explorative study.

    PubMed

    Kloosterman, Marieke G M; Snoek, Govert J; Kouwenhoven, Mirjam; Nene, Anand V; Jannink, Michiel J A

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation); however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval) with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5°) during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°). Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%), anterior part of deltoid (37.7% +/- 16.7%), posterior part of deltoid (32.0% +/- 13.9%), and long head biceps (49.6% +/- 20.0%). Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy) should be further investigated with a larger population. PMID:21110258

  17. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level.

    PubMed

    Hakan, Tayfun; Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  18. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level

    PubMed Central

    Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  19. Spinal tumor

    MedlinePlus

    Tumor - spinal cord ... spinal tumors occur in the nerves of the spinal cord itself. Most often these are ependymomas and other ... gene mutations. Spinal tumors can occur: Inside the spinal cord (intramedullary) In the membranes (meninges) covering the spinal ...

  20. Spinal stenosis

    MedlinePlus

    ... spinal stenosis; Foraminal spinal stenosis; Degenerative spine disease; Back pain - spinal stenosis ... help your pain during flare-ups. Treatments for back pain caused by spinal stenosis include: Medicines that may ...

  1. Corpectomy with Adjacent-Level Kyphoplasty to Treat Metastatic Lung Cancer in Three Contiguous Cervical Vertebrae Causing Focal Neurologic Compromise

    PubMed Central

    Bateman, Antony H.; Way, Adam C.

    2014-01-01

    Study Design Case report. Objectives Decompression of metastatic spinal cord compression has been shown to improve quality of life and prolong ambulation in patients undergoing palliative treatment. We report a case of metastatic cervical myelopathy treated with a combined approach using corpectomy and stabilization together with balloon kyphoplasty to allow adequate decompression and immediate stability in a patient with significant destruction of adjacent vertebral bodies. Methods The cervical spine was approached anteriorly and decompressed with a C7 corpectomy. Subsequent stability was achieved with insertion of a trabecular metal cage. Balloon kyphoplasty was used to treat lytic lesions within the posterior body of the adjacent vertebrae for pain relief and increased stability. Additional stability was achieved through the application of an anterior plate. Results Full limited decompression and stabilization were successfully achieved. The patient had no further neurologic deterioration and made modest improvements that allowed a return to independent ambulation. Conclusion This limited approach may be an option for patients with metastatic spinal cord compression, lytic destruction of adjacent vertebral bodies, and limited life expectancy. PMID:25844288

  2. Spinal injury

    MedlinePlus

    ... head. Alternative Names Spinal cord injury; SCI Images Skeletal spine Vertebra, cervical (neck) Vertebra, lumbar (low back) Vertebra, thoracic (mid back) Vertebral column Central nervous system Spinal cord injury Spinal anatomy Two person roll - ...

  3. Spinal fusion

    MedlinePlus

    ... Anterior spinal fusion; Spine surgery - spinal fusion; Low back pain - fusion; Herniated disk - fusion ... If you had chronic back pain before surgery, you will likely still have some pain afterward. Spinal fusion is unlikely to take away all your pain ...

  4. Spinal stenosis

    MedlinePlus

    ... injection (ESI) involves injecting medicine directly into the space around your spinal nerves or spinal cord. Spinal stenosis symptoms often become worse over time, but this may happen slowly. If the pain ...

  5. Retraining the injured spinal cord

    NASA Technical Reports Server (NTRS)

    Edgerton, V. R.; Leon, R. D.; Harkema, S. J.; Hodgson, J. A.; London, N.; Reinkensmeyer, D. J.; Roy, R. R.; Talmadge, R. J.; Tillakaratne, N. J.; Timoszyk, W.; Tobin, A.

    2001-01-01

    The present review presents a series of concepts that may be useful in developing rehabilitative strategies to enhance recovery of posture and locomotion following spinal cord injury. First, the loss of supraspinal input results in a marked change in the functional efficacy of the remaining synapses and neurons of intraspinal and peripheral afferent (dorsal root ganglion) origin. Second, following a complete transection the lumbrosacral spinal cord can recover greater levels of motor performance if it has been exposed to the afferent and intraspinal activation patterns that are associated with standing and stepping. Third, the spinal cord can more readily reacquire the ability to stand and step following spinal cord transection with repetitive exposure to standing and stepping. Fourth, robotic assistive devices can be used to guide the kinematics of the limbs and thus expose the spinal cord to the new normal activity patterns associated with a particular motor task following spinal cord injury. In addition, such robotic assistive devices can provide immediate quantification of the limb kinematics. Fifth, the behavioural and physiological effects of spinal cord transection are reflected in adaptations in most, if not all, neurotransmitter systems in the lumbosacral spinal cord. Evidence is presented that both the GABAergic and glycinergic inhibitory systems are up-regulated following complete spinal cord transection and that step training results in some aspects of these transmitter systems being down-regulated towards control levels. These concepts and observations demonstrate that (a) the spinal cord can interpret complex afferent information and generate the appropriate motor task; and (b) motor ability can be defined to a large degree by training.

  6. Spinal Tuberculosis

    PubMed Central

    Ekinci, Safak; Tatar, Oner; Akpancar, Serkan; Bilgic, Serkan; Ersen, Omer

    2015-01-01

    Spinal tuberculosis (TB) is a significant form of TB, causing spinal deformity and paralysis. Early diagnosis and treatment are crucial for avoiding multivertebral destruction and are critical for improving outcomes in spinal TB. We believe that appropriate treatment method should be implemented at the early stage of this disease and that the Gulhane Askeri Tıp Akademisi classification system can be considered a practical guide for spinal TB treatment planning in all countries. PMID:26609247

  7. Kinematic resection

    NASA Astrophysics Data System (ADS)

    Shevlin, Fergal P.

    1995-01-01

    A new geometric formulation is given for the problem of determining position and orientation of a satellite scanner from error-prone ground control point observations in linear pushbroom imagery. The pushbroom satellite resection problem is significantly more complicated than that of the conventional frame camera because of irregular platform motion throughout the image capture period. Enough ephemeris data are typically available to reconstruct satellite trajectory and hence the interior orientation of the pushbroom imagery. The new approach to resection relies on the use of reconstructed scanner interior orientation to determine the relative orientations of a bundle of image rays. The absolute position and orientation which allows this bundle to minimize its distance from a corresponding set of ground control points may then be found. The interior orientation is represented as a kinematic chain of screw motions, implemented as dual-number quaternions. The motor algebra is used in the analysis since it provides a means of line, point, and motion manipulation. Its moment operator provides a metric of distance between the image ray and the ground control point.

  8. Spinal anaesthesia for spinal surgery.

    PubMed

    Jellish, W Scott; Shea, John F

    2003-09-01

    Spinal anaesthesia for spinal surgery is becoming increasingly more popular because this anaesthetic technique allows the patient to self-position and avoid neurological injury that may occur with prone positioning under general anaesthesia. Spinal anaesthesia reduces intraoperative surgical blood loss, improves perioperative haemodynamic stability and reduces pain in the immediate postoperative period. This leads to a reduced need for analgesics and a reduction in the incidence of nausea and vomiting in the postoperative setting. Spinal anaesthesia for lumbar spine surgery also decreases the incidence of lower extremity thrombo-embolic complications and does not increase the occurrence of problems with micturition. These benefits increase the patient's satisfaction, and they expedite discharge of the patient from the hospital. Combination anaesthetic techniques, using both subarachnoid and epidural dosing schemes, may be beneficial for improving postoperative pain control and add further to the benefit of spinal anaesthesia for lumbar spine surgical procedures. PMID:14529005

  9. Spinal Stenosis

    MedlinePlus

    ... all. They include Pain in your neck or back Numbness, weakness, cramping, or pain in your arms or legs Pain going down the leg Foot problems Doctors diagnose spinal stenosis with a physical exam and ...

  10. Spinal deformity.

    PubMed

    Bunnell, W P

    1986-12-01

    Spinal deformity is a relatively common disorder, particularly in teenage girls. Early detection is possible by a simple, quick visual inspection that should be a standard part of the routine examination of all preteen and teenage patients. Follow-up observation will reveal those curvatures that are progressive and permit orthotic treatment to prevent further increase in the deformity. Spinal fusion offers correction and stabilization of more severe degrees of scoliosis. PMID:3786010

  11. Spinal cord trauma

    MedlinePlus

    Spinal cord injury; Compression of spinal cord; SCI; Cord compression ... them more likely to fall may also have spinal cord injury. ... vary depending on the location of the injury. Spinal cord injury causes weakness and loss of feeling at, and ...

  12. Spinal stenosis.

    PubMed

    Melancia, João Levy; Francisco, António Fernandes; Antunes, João Lobo

    2014-01-01

    Narrowing of the spinal canal or foramina is a common finding in spine imaging of the elderly. Only when symptoms of neurogenic claudication and/or cervical myelopathy are present is a spinal stenosis diagnosis made, either of the lumbar spine, cervical spine or both (only very rarely is the thoracic spine involved). Epidemiological data suggest an incidence of 1 case per 100 000 for cervical spine stenosis and 5 cases per 100 000 for lumbar spine stenosis. Cervical myelopathy in patients over 50 years of age is most commonly due to cervical spine stenosis. Symptomatic spinal narrowing can be congenital, or, more frequently, acquired. The latter may be the result of systemic illneses, namely endocrinopathies (such as Cushing disease or acromegaly), calcium metabolism disorders (including hyporarthyroidism and Paget disease), inflammatory diseases (such as rheumathoid arthritis) and infectious diseases. Physical examination is more often abnormal in cervical spondylotic myeloptahy whereas in lumbar spinal stenosis it is typically normal. Therefore spinal stenosis diagnosis relies on the clinical picture corresponding to conspicuous causative changes identified by imaging techniques, most importantly CT and MRI. Other ancillary diagnostic tests are more likely to be yielding for establishing a differential diagnosis, namely vascular claudication. Most patients have a progressive presentation and are offered non operative management as first treatment strategy. Surgery is indicated for progressive intolerable symptoms or, more rarely, for the neurologically catastrophic initial presentations. Surgical strategy consists mainly of decompression (depending on the anatomical level and type of narrowing: laminectomy, foraminotomy, discectomy, corporectomy) with additional instrumentation should spinal stability and sagittal balance be at risk. For cervical spine stenosis the main objective of surgery is to halt disease progression. There is class 1b evidence that surgery

  13. Global and segmental kinematic changes following sequential resection of posterior osteoligamentous structures in the lumbar spine: An in vitro biomechanical investigation using pure moment testing protocols.

    PubMed

    Chamoli, Uphar; Korkusuz, Mert H; Sabnis, Ashutosh B; Manolescu, Andrei R; Tsafnat, Naomi; Diwan, Ashish D

    2015-11-01

    Lumbar spinal surgeries may compromise the integrity of posterior osteoligamentous structures implicating mechanical stability. Circumstances necessitating a concomitant surgery to achieve restabilisation are not well understood. The main objective of this in vitro study was to quantify global and segmental (index and adjacent levels) kinematic changes in the lumbar spine following sequential resection of the posterior osteoligamentous structures using pure moment testing protocols. Six fresh frozen cadaveric kangaroo lumbar spines (T12-S1) were tested under a bending moment in flexion-extension, bilateral bending, and axial torsion in a 6-degree-of-freedom Kinematic Spine Simulator. Specimens were tested in the following order: intact state (D0), after interspinous and supraspinous ligaments transection between L4 and L5 (D1), further after a total bilateral facetectomy between L4 and L5 (D2). Segmental motions at the cephalad, damaged, and caudal levels were recorded using an infrared-based motion tracking device. Following D1, no significant change in the global range of motion was observed in any of the bending planes. Following D2, a significant increase in the global range of motion from the baseline (D0) was observed in axial torsion (median normalised change +20%). At the damaged level, D2 resulted in a significant increase in the segmental range of motion in flexion-extension (+77%) and axial torsion (+492%). Additionally, a significant decrease in the segmental range of motion in axial torsion (-35%) was observed at the caudal level following D2. These results suggest that a multi-segment lumbar spine acts as a mechanism for transmitting motions, and that a compromised joint may significantly alter motion transfer to adjacent segments. We conclude that the interspinous and supraspinous ligaments play a modest role in restricting global spinal motions within physiologic limits. Following interspinous and supraspinous ligaments transection, a total

  14. Spinal Osteosarcoma

    PubMed Central

    Katonis, P.; Datsis, G.; Karantanas, A.; Kampouroglou, A.; Lianoudakis, S.; Licoudis, S.; Papoutsopoulou, E.; Alpantaki, K.

    2013-01-01

    Although osteosarcoma represents the second most common primary bone tumor, spinal involvement is rare, accounting for 3%–5% of all osteosarcomas. The most frequent symptom of osteosarcoma is pain, which appears in almost all patients, whereas more than 70% exhibit neurologic deficit. At a molecular level, it is a tumor of great genetic complexity and several genetic disorders have been associated with its appearance. Early diagnosis and careful surgical staging are the most important factors in accomplishing sufficient management. Even though overall prognosis remains poor, en-block tumor removal combined with adjuvant radiotherapy and chemotherapy is currently the treatment of choice. This paper outlines histopathological classification, epidemiology, diagnostic procedures, and current concepts of management of spinal osteosarcoma. PMID:24179411

  15. Spinal Bracing

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Dr. Arthur Copes of the Copes Foundation, Baton Rouge, LA, says that 35 percent of the 50 technical reports he received from the NASA/Southern University Industrial Applications Center in Baton Rouge and the Central Industrial Applications Center, Durant, OK, were vital to the development of his Copes Scoliosis Braces, which are custom designed and feature a novel pneumatic bladder that exerts constant corrective pressure to the torso to slowly reduce or eliminate the spinal curve.

  16. Spinal injury - resources

    MedlinePlus

    Resources - spinal injury ... The following organizations are good resources for information on spinal injury : National Institute of Neurological Disorders and Stroke -- www.ninds.nih.gov The National Spinal Cord Injury ...

  17. Spinal Cord Injuries

    MedlinePlus

    Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back ... forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually ...

  18. Spinal Cord Injury Map

    MedlinePlus

    ... on the severity of the injury. Tap this spinal column to see how the level of injury affects loss of function and control. Learn more about spinal cord injuries. A spinal cord injury affects the ...

  19. Tethered Spinal Cord Syndrome

    MedlinePlus

    ... Enhancing Diversity Find People About NINDS NINDS Tethered Spinal Cord Syndrome Information Page Table of Contents (click to ... being done? Clinical Trials Organizations What is Tethered Spinal Cord Syndrome? Tethered spinal cord syndrome is a neurological ...

  20. Spinal Cord Infarction

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Spinal Cord Infarction Information Page Table of Contents (click to ... Organizations Related NINDS Publications and Information What is Spinal Cord Infarction? Spinal cord infarction is a stroke either ...

  1. Spinal Cord Diseases

    MedlinePlus

    Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back ... of the spine, this can also injure the spinal cord. Other spinal cord problems include Tumors Infections such ...

  2. Spinal surgery -- cervical - series (image)

    MedlinePlus

    The cervical spinal column is made up of vertebral bodies which protect the spinal cord. ... spinal nerves, trauma, and narrowing (stenosis) of the spinal column around the spinal cord. Symptoms of cervical spine ...

  3. Three tooth kinematic coupling

    DOEpatents

    Hale, Layton C.

    2000-01-01

    A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  4. Three tooth kinematic coupling

    SciTech Connect

    Hale, L.C.

    2000-05-23

    A three tooth kinematic coupling is disclosed based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  5. Spinal Cord Diseases

    MedlinePlus

    ... this can also injure the spinal cord. Other spinal cord problems include Tumors Infections such as meningitis and polio Inflammatory diseases Autoimmune diseases Degenerative diseases such as amyotrophic lateral ...

  6. Spinal cord trauma

    MedlinePlus

    ... that can be removed or reduced before the spinal nerves are completely destroyed, paralysis may improve. Surgery may be needed to: Realign the spinal bones (vertebrae) Remove fluid or tissue that presses ...

  7. Spinal fusion - series (image)

    MedlinePlus

    The vertebrae are the bones that make up the spinal column, which surrounds and protects the spinal cord. The ... disks are soft tissues that sit between each vertebrae and act as cushions between vertebrae, and absorb ...

  8. Spinal cord stimulation

    MedlinePlus

    Spinal cord stimulation is a treatment for pain that uses a mild electric current to block nerve impulses ... stretched into the space on top of your spinal cord. These wires will be connected to a small ...

  9. Teaching about Kinematics

    ERIC Educational Resources Information Center

    Nelson, Jane Bray; Nelson, Jim

    2009-01-01

    Written by Jim and Jane Nelson, Teaching About Kinematics is the latest AAPT/PTRA resource book. Based on physics education research, the book provides teachers with the resources needed to introduce students to some of the fundamental building blocks of physics. It is a carefully thought-out, step-by-step laboratory-based introduction to the…

  10. Kinematically redundant robot manipulators

    NASA Technical Reports Server (NTRS)

    Baillieul, J.; Hollerbach, J.; Brockett, R.; Martin, D.; Percy, R.; Thomas, R.

    1987-01-01

    Research on control, design and programming of kinematically redundant robot manipulators (KRRM) is discussed. These are devices in which there are more joint space degrees of freedom than are required to achieve every position and orientation of the end-effector necessary for a given task in a given workspace. The technological developments described here deal with: kinematic programming techniques for automatically generating joint-space trajectories to execute prescribed tasks; control of redundant manipulators to optimize dynamic criteria (e.g., applications of forces and moments at the end-effector that optimally distribute the loading of actuators); and design of KRRMs to optimize functionality in congested work environments or to achieve other goals unattainable with non-redundant manipulators. Kinematic programming techniques are discussed, which show that some pseudo-inverse techniques that have been proposed for redundant manipulator control fail to achieve the goals of avoiding kinematic singularities and also generating closed joint-space paths corresponding to close paths of the end effector in the workspace. The extended Jacobian is proposed as an alternative to pseudo-inverse techniques.

  11. Kinematics of Tape Recording.

    ERIC Educational Resources Information Center

    Coleman, J. J.

    1982-01-01

    Describes mathematics of the nonliner relationships between a constant-speed, capstan-driven magnetic tape transport mechanism and a constant-angular-velocity take-up reel. The relationship, derived from the sum of a partial, serves in recognition of a finite tape. Thickness can serve as an example of rotational kinematics. (Author/SK)

  12. Brain and Spinal Tumors

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Brain and Spinal Tumors Information Page Synonym(s): Spinal Cord ... en Español Additional resources from MedlinePlus What are Brain and Spinal Tumors? Tumors of the brain and ...

  13. Spinal Cord Injuries

    MedlinePlus

    ... forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures or ... down on the nerve parts that carry signals. Spinal cord injuries can be complete or incomplete. With a complete ...

  14. Spinaplasty following lumbar laminectomy for multilevel lumbar spinal stenosis to prevent iatrogenic instability

    PubMed Central

    Tuli, Surendra Mohan; Kapoor, Varun; Jain, Anil K; Jain, Saurabh

    2011-01-01

    Background: Iatrogenic instability following laminectomy occurs in patients with degenerative lumbar canal stenosis. Long segment fusions to obviate postoperative instability result in loss of motion of lumbar spine and predisposes to adjacent level degeneration. The best alternative would be an adequate decompressive laminectomy with a nonfusion technique of preserving the posterior ligament complex integrity. We report a retrospective analysis of multilevel lumbar canal stenosis that were operated for posterior decompression and underwent spinaplasty to preserve posterior ligament complex integrity for outcome of decompression and iatrogenic instability. Materials and Methods: 610 patients of degenerative lumbar canal stenosis (n=520) and development spinal canal stenosis (n=90), with a mean age 58 years (33–85 years), underwent multilevel laminectomies and spinaplasty procedure. At followup, changes in the posture while walking, increase in the walking distance, improvement in the dysesthesia in lower limb, the motor power, capability to negotiate stairs and sphincter function were assessed. Forward excursion of vertebrae more than 4 mm in flexion–extension lateral X-ray of the spine as compared to the preoperative movements was considered as the iatrogenic instability. Clinical assessment was done in standing posture regarding active flexion–extension movement, lateral bending and rotations Results: All patients were followed up from 3 to 10 years. None of the patients had neurological deterioration or pain or catch while movement. Walking distance improved by 5–10 times, with marked relief (70–90%) in neurogenic claudication and preoperative stooping posture, with improvement in sensation and motor power. There was no significant difference in the sagittal alignment as well as anterior translation. Two patients with concomitant scoliosis and one with cauda equine syndrome had incomplete recovery. Two patients who developed disc protrusion, underwent

  15. Occupant Kinematics in Laboratory Rollover Tests: ATD Response and Biofidelity.

    PubMed

    Zhang, Qi; Lessley, David L; Riley, Patrick; Toczyski, Jacek; Lockerby, Jack; Foltz, Patrick; Overby, Brian; Seppi, Jeremy; Crandall, Jeff R; Kerrigan, Jason R

    2014-11-01

    Rollover crashes are a serious public health problem in United States, with one third of traffic fatalities occurring in crashes where rollover occurred. While it has been shown that occupant kinematics affect the injury risk in rollover crashes, no anthropomorphic test device (ATD) has yet demonstrated kinematic biofidelity in rollover crashes. Therefore, the primary goal of this study was to assess the kinematic response biofidelity of six ATDs (Hybrid III, Hybrid III Pedestrian, Hybrid III with Pedestrian Pelvis, WorldSID, Polar II and THOR) by comparing them to post mortem human surrogate (PMHS) kinematic response targets published concurrently; and the secondary goal was to evaluate and compare the kinematic response differences among these ATDs. Trajectories (head, T1, T4, T10, L1 and sacrum), spinal segment (head-to-T1, T1-to-T4, T4-T10, T10-L1, and L1-to-sacrum) rotations relative to the rollover buck, and spinal segment extension/compression were calculated from the collected kinematics data from an optical motion tracking system. Response differences among the ATDs were observed mainly due to the different lateral bending stiffness of the spine from their varied architecture, while the additional thoracic joint in Polar II and THOR did not seem to provide more flexion/extension compliance than the other ATDs. In addition, the ATD response data were compared to PMHS response corridors developed from similar tests for assessing ATD biofidelity. All of the ATDs, generally, drifted outboard and upward during the tests similar to the PMHS. However, accompanied with this upward and outward motion, the ATD head and upper torso pitched forward (~10 degrees) while the PMHS' head and upper torso pitching rearward (~10 to ~15 degrees), due to the absence of flexion/extension compliance in the ATD spine. The differences in these pitch motions resulted in a difference of 130 mm to 160 mm in the longitudinal position of the head at 195 degrees of roll angle. Finally

  16. Closed-loop neuromodulation of spinal sensorimotor circuits controls refined locomotion after complete spinal cord injury.

    PubMed

    Wenger, Nikolaus; Moraud, Eduardo Martin; Raspopovic, Stanisa; Bonizzato, Marco; DiGiovanna, Jack; Musienko, Pavel; Morari, Manfred; Micera, Silvestro; Courtine, Grégoire

    2014-09-24

    Neuromodulation of spinal sensorimotor circuits improves motor control in animal models and humans with spinal cord injury. With common neuromodulation devices, electrical stimulation parameters are tuned manually and remain constant during movement. We developed a mechanistic framework to optimize neuromodulation in real time to achieve high-fidelity control of leg kinematics during locomotion in rats. We first uncovered relationships between neuromodulation parameters and recruitment of distinct sensorimotor circuits, resulting in predictive adjustments of leg kinematics. Second, we established a technological platform with embedded control policies that integrated robust movement feedback and feed-forward control loops in real time. These developments allowed us to conceive a neuroprosthetic system that controlled a broad range of foot trajectories during continuous locomotion in paralyzed rats. Animals with complete spinal cord injury performed more than 1000 successive steps without failure, and were able to climb staircases of various heights and lengths with precision and fluidity. Beyond therapeutic potential, these findings provide a conceptual and technical framework to personalize neuromodulation treatments for other neurological disorders. PMID:25253676

  17. Spinal surgery -- cervical - series (image)

    MedlinePlus

    ... on the vertebral bodies (osteophytes), which compress spinal nerves, trauma, and narrowing (stenosis) of the spinal column around the spinal cord. Symptoms of cervical spine problems include: pain that interferes with daily ...

  18. Shot-put kinematics

    NASA Astrophysics Data System (ADS)

    DeLuca, R.

    2005-11-01

    The problem of the optimum throw in the shot-put discipline is analysed by relaxing the assumption that the height H, from which the athlete releases the shot, does not depend on the angle θ which the arm of the putter makes with the horizontal axis. In this context, the kinematics of the shot-put is studied and results are compared with the traditional analysis, which considers the height H, the angle θ and the modulus V0 of the initial velocity of the metal sphere as independent parameters.

  19. Influence of Fatigue in Neuromuscular Control of Spinal Stability

    PubMed Central

    Granata, Kevin P.; Slota, Greg P.; Wilson, Sara E.

    2006-01-01

    Lifting-induced fatigue may influence neuromuscular control of spinal stability. Stability is primarily controlled by muscle recruitment, active muscle stiffness, and reflex response. Fatigue has been observed to affect each of these neuromuscular parameters and may therefore affect spinal stability. A biomechanical model of spinal stability was implemented to evaluate the effects of fatigue on spinal stability. The model included a 6-degree-of-freedom representation of the spine controlled by 12 deformable muscles from which muscle recruitment was determined to simultaneously achieve equilibrium and stability. Fatigue-induced reduction in active muscle stiffness necessitated increased antagonistic cocontraction to maintain stability resulting in increased spinal compression with fatigue. Fatigueinduced reduction in force-generating capacity limited the feasible set of muscle recruitment patterns, thereby restricting the estimated stability of the spine. Electromyographic and trunk kinematics from 21 healthy participants were recorded during sudden-load trials in fatigued and unfatigued states. Empirical data supported the model predictions, demonstrating increased antagonistic cocontraction during fatigued exertions. Results suggest that biomechanical factors including spinal load and stability should be considered when performing ergonomic assessments of fatiguing lifting tasks. Potential applications of this research include a biomechanical tool for the design of administrative ergonomic controls in manual materials handling industries. PMID:15151156

  20. Kinematics of Strong Discontinuities

    NASA Technical Reports Server (NTRS)

    Peterson, K.; Nguyen, G.; Sulsky, D.

    2006-01-01

    Synthetic Aperture Radar (SAR) provides a detailed view of the Arctic ice cover. When processed with the RADARSAT Geophysical Processor System (RGPS), it provides estimates of sea ice motion and deformation over large regions of the Arctic for extended periods of time. The deformation is dominated by the appearance of linear kinematic features that have been associated with the presence of leads. The RGPS deformation products are based on the assumption that the displacement and velocity are smooth functions of the spatial coordinates. However, if the dominant deformation of multiyear ice results from the opening, closing and shearing of leads, then the displacement and velocity can be discontinuous. This presentation discusses the kinematics associated with strong discontinuities that describe possible jumps in displacement or velocity. Ice motion from SAR data are analyzed using this framework. It is assumed that RGPS cells deform due to the presence of a lead. The lead orientation is calculated to optimally account for the observed deformation. It is shown that almost all observed deformation can be represented by lead opening and shearing. The procedure used to reprocess motion data to account for leads will be described and applied to regions of the Beaufort Sea. The procedure not only provides a new view of ice deformation, it can be used to obtain information about the presence of leads for initialization and/or validation of numerical simulations.

  1. Load- and displacement-controlled finite element analyses on fusion and non-fusion spinal implants.

    PubMed

    Zhong, Z-C; Chen, S-H; Hung, C-H

    2009-02-01

    This study used finite element (FE) analysis with the load-controlled method (LCM) and the displacement-controlled method (DCM) to examine motion differences at the implant level and adjacent levels between fusion and non-fusion implants. A validated three-dimensional intact (INT) L1-L5 FE model was used. At the L3-L4 level, the INT model was modified to surgery models, including the artificial disc replacement (ADR) of ProDisc II, and the anterior lumbar interbody fusion (ALIF) cage with pedicle screw fixation. The LCM imposed 10 Nm moments of four physiological motions and a 150 N preload at the top of L1. The DCM process was in accordance with the hybrid testing protocol. The average percentage changes in the range of motion (ROM) for whole non-operated levels were used to predict adjacent level effects (ALE%). At the implant level, the ALIF model showed similar stability with both control methods. The ADR model using the LCM had a higher ROM than the model using the DCM, especially in extension and torsion. At the adjacent levels, the ALIF model increased ALE% (at least 17 per cent) using the DCM compared with the LCM. The ADR model had an ALE% close to that of the INT model, using the LCM (average within 6 per cent), while the ALE% decreased when using the DCM. The study suggests that both control methods can be adopted to predict the fusion model at the implant level, and similar stabilization characteristics can be found. The LCM will emphasize the effects of the non-fusion implants. The DCM was more clinically relevant in evaluating the fusion model at the adjacent levels. In conclusion, both the LCM and the DCM should be considered in numerical simulations to obtain more realistic data in spinal implant biomechanics. PMID:19278192

  2. Human Spinal Motor Control.

    PubMed

    Nielsen, Jens Bo

    2016-07-01

    Human studies in the past three decades have provided us with an emerging understanding of how cortical and spinal networks collaborate to ensure the vast repertoire of human behaviors. Humans have direct cortical connections to spinal motoneurons, which bypass spinal interneurons and exert a direct (willful) muscle control with the aid of a context-dependent integration of somatosensory and visual information at cortical level. However, spinal networks also play an important role. Sensory feedback through spinal circuitries is integrated with central motor commands and contributes importantly to the muscle activity underlying voluntary movements. Regulation of spinal interneurons is used to switch between motor states such as locomotion (reciprocal innervation) and stance (coactivation pattern). Cortical regulation of presynaptic inhibition of sensory afferents may focus the central motor command by opening or closing sensory feedback pathways. In the future, human studies of spinal motor control, in close collaboration with animal studies on the molecular biology of the spinal cord, will continue to document the neural basis for human behavior. PMID:27023730

  3. Spinal subarachnoid haematoma after spinal anaesthesia: case report.

    PubMed

    Vidal, Marion; Strzelecki, Antoine; Houadec, Mireille; Krikken, Isabelle Ranz; Danielli, Antoine; Souza Neto, Edmundo Pereira de

    2016-01-01

    Subarachnoid haematoma after spinal anaesthesia is known to be very rare. In the majority of these cases, spinal anaesthesia was difficult to perform and/or unsuccessful; other risk factors included antiplatelet or anticoagulation therapy, and direct spinal cord trauma. We report a case of subarachnoid haematoma after spinal anaesthesia in a young patient without risk factors. PMID:27591468

  4. Kinematically Detected Halo Streams

    NASA Astrophysics Data System (ADS)

    Smith, Martin C.

    Clues to the origins and evolution of our Galaxy can be found in the kinematics of stars around us. Remnants of accreted satellite galaxies produce over-densities in velocity-space, which can remain coherent for much longer than spatial over-densities. This chapter reviews a number of studies that have hunted for these accretion relics, both in the nearby solar-neighborhood and the more-distant stellar halo. Many observational surveys have driven this field forwards, from early work with the Hipparcos mission, to contemporary surveys like RAVE and SDSS. This active field continues to flourish, providing many new discoveries, and will be revolutionized as the Gaia mission delivers precise proper motions for a billion stars in our Galaxy.

  5. Rattlesnake strike behavior: kinematics

    PubMed

    Kardong; v

    1998-03-01

    The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

    PMID:9464964

  6. Integration of sensory, spinal, and volitional descending inputs in regulation of human locomotion.

    PubMed

    Gerasimenko, Yury; Gad, Parag; Sayenko, Dimitry; McKinney, Zach; Gorodnichev, Ruslan; Puhov, Aleksandr; Moshonkina, Tatiana; Savochin, Aleksandr; Selionov, Victor; Shigueva, Tatiana; Tomilovskaya, Elena; Kozlovskaya, Inessa; Edgerton, V Reggie

    2016-07-01

    We reported previously that both transcutaneous electrical spinal cord stimulation and direct pressure stimulation of the plantar surfaces of the feet can elicit rhythmic involuntary step-like movements in noninjured subjects with their legs in a gravity-neutral apparatus. The present experiments investigated the convergence of spinal and plantar pressure stimulation and voluntary effort in the activation of locomotor movements in uninjured subjects under full body weight support in a vertical position. For all conditions, leg movements were analyzed using electromyographic (EMG) recordings and optical motion capture of joint kinematics. Spinal cord stimulation elicited rhythmic hip and knee flexion movements accompanied by EMG bursting activity in the hamstrings of 6/6 subjects. Similarly, plantar stimulation induced bursting EMG activity in the ankle flexor and extensor muscles in 5/6 subjects. Moreover, the combination of spinal and plantar stimulation exhibited a synergistic effect in all six subjects, eliciting greater motor responses than either modality alone. While the motor responses to spinal vs. plantar stimulation seems to activate distinct but overlapping spinal neural networks, when engaged simultaneously, the stepping responses were functionally complementary. As observed during induced (involuntary) stepping, the most significant modulation of voluntary stepping occurred in response to the combination of spinal and plantar stimulation. In light of the known automaticity and plasticity of spinal networks in absence of supraspinal input, these findings support the hypothesis that spinal and plantar stimulation may be effective tools for enhancing the recovery of motor control in individuals with neurological injuries and disorders. PMID:27075538

  7. Occupant Kinematics in Laboratory Rollover Tests: PMHS Response.

    PubMed

    Lessley, David J; Riley, Patrick; Zhang, Qi; Foltz, Patrick; Overby, Brian; Heltzel, Sara; Sochor, Mark; Crandall, Jeff; Kerrigan, Jason R

    2014-11-01

    The objective of the current study was to characterize the whole-body kinematic response of restrained PMHS in controlled laboratory rollover tests. A dynamic rollover test system (DRoTS) and a parametric vehicle buck were used to conduct 36 rollover tests on four adult male PMHS with varied test conditions to study occupant kinematics during the rollover event. The DRoTS was used to drop/catch and rotate the test buck, which replicated the occupant compartment of a typical mid-sized SUV, around its center of gravity without roof-to-ground contact. The studied test conditions included a quasi-static inversion (4 tests), an inverted drop and catch that produced a 3 g vertical deceleration (4 tests), a pure dynamic roll at 360 degrees/second (11 tests), and a roll with a superimposed drop and catch produced vertical deceleration (17 tests). Each PMHS was restrained with a three-point belt and was tested in both leading-side and trailing-side front-row seating positions. Whole-body kinematics were measured using a 3D motion capture system that quantified occupant displacement relative to the vehicle buck for the X-axis (longitudinal), Y-axis (lateral), and Z-axis (vertical) directions. Additionally the spine was divided into five segments to describe intrasegmental kinematics of the spine, including segment rotations as well as spinal extension and compression. The reported data represent the most complete set of kinematic response targets for a restrained occupant in a variety of dynamic rollover conditions, and are immediately useful for efforts to evaluate and improve existing ATDs and computational models for use in the rollover crash environment. PMID:26192958

  8. Irradiation of Spinal Metastases: Should We Continue to Include One Uninvolved Vertebral Body Above and Below in the Radiation Field?

    SciTech Connect

    Klish, Darren S.; Grossman, Patricia; Allen, Pamela K.; Rhines, Laurence D.; Chang, Eric L.

    2011-12-01

    Purpose: Historically, the appropriate target volume to be irradiated for spinal metastases is 1-2 vertebral bodies above and below the level of involvement for three reasons: (1) to avoid missing the correct level in the absence of simulation or (2) to account for the possibility of spread of disease to the adjacent level, and (3) to account for beam penumbra. In this study, we hypothesized that isolated failures occurring in the level adjacent to level treated with stereotactic body radiosurgery (SBRS) were infrequent and that with improved localization techniques with image-guided radiation therapy, treatment of only the involved level of spinal metastases may be more appropriate. Methods and Materials: Patients who had received SBRS treatments to only the involved level of the spine as part of a prospective trial for spinal metastases comprised the study population. Follow-up imaging with spine MRI was performed at 3-month intervals following initial treatment. Failures in the adjacent (V{+-}1, V{+-}2) and distant spine were identified and classified accordingly. Results: Fifty-eight patients met inclusion criteria for this study and harbored 65 distinct spinal metastases. At 18-month median follow-up, seven (10.7%) patients failed simultaneously at adjacent levels V{+-}1 and at multiple sites throughout the spine. Only two (3%) patients experienced isolated, solitary adjacent failures at 9 and 11 months, respectively. Conclusion: Isolated local failures of the unirradiated adjacent vertebral bodies may occur in <5% of patients with isolated spinal metastasis. On the basis of the data, the current practice of irradiating one vertebral body above and below seems unnecessary and could be revised to irradiate only the involved level(s) of the spine metastasis.

  9. CME Kinematics and Dynamics

    NASA Astrophysics Data System (ADS)

    Lin, C.-H.; Gallagher, P. T.

    The goal of this study is to investigate the driving mechanisms of CMEs and to infer the magnetic field properties at the onset of the instability. We use EIT 195 Å images and LASCO white-light coronagraph data of a CME event that occurred on 17 December 2006. It was a long-duration event, and was associated with an occulted C2.1 class flare. To determine the driving mechanism, we quantitatively and qualitatively compared the observationally obtained kinematic evolution with that predicted by three CME models: the breakout model (BO, see Antiochos et al. 1999; Lynch et al. 2008; DeVore and Antiochos 2008), the catastrophe model (CM, see Priest and Forbes 2000), and the toroidal instability model (TI, see Chen 1989; Kliem and Török 2006). Our results indicate that this CME is best represented by the CM model. We infer that, at the onset of the instability, the Alfvén speed is approximately 120 km s-1 and the height of the flux rope is roughly 100-200Mm. These parameter values are related to the magnetic environment and the loop geometry and can be used to infer the magnetic condition at the onset of the eruption.We intend to submit the full analysis to A&A.

  10. Why Teach Kinematics?

    NASA Astrophysics Data System (ADS)

    Dykstra, Dewey

    2002-05-01

    The development of two new units for the Powerful Ideas in Physical Science (PIPS) Project of the American Association of Physics Teachers, funded by the National Science Foundation has motivated another look at the learning and teaching of kinematics and force. These and some of the other units of the PIPS Project are unique in that they advocate and model a particular student understanding driven approach to instruction as opposed to the more common content driven approach. Several novel ways to view the results of using these new motion and force materials are introduced and made possible by a diagnostic capable of indicating the degree of presence of multiple views (the Force and Motion Conceptual Evaluation by Thornton and Sokoloff). The performance of individuals on pre and post diagnostic measures ranges widely from almost no change to more than 6 standard deviations. Factors are identified which appear to differentiate the student performances. The identification of these factors motivated additional rounds of modifications to the materials, departing even further from a content driven orientation toward an even more student understanding driven approach. The resulting instruction appears to induce routinely even under adverse teaching and learning conditions 2.5 standard deviations change in the class average on the pre to the post instruction diagnostic scores.

  11. What Is Spinal Stenosis?

    MedlinePlus

    ... To order the Sports Injuries Handout on Health full-text version, please contact NIAMS using the contact information ... publication. To order the Spinal Stenosis Q&A full-text version, please contact NIAMS using the contact information ...

  12. Spinal cord abscess

    MedlinePlus

    ... abscess is caused by an infection inside the spine. An abscess of the spinal cord itself is ... by a staphylococcus infection that spreads through the spine. It may be caused by tuberculosis in some ...

  13. Spinal Cord Injury

    MedlinePlus

    ... Dramatically Improves Function After Spinal Cord Injury in Rats May 2004 press release on an experimental treatment ... NINDS). Signaling Molecule Improves Nerve Cell Regeneration in Rats August 2002 news summary on a signaling molecule ...

  14. Spinal cord schistosomiasis

    PubMed Central

    Adeel, Ahmed Awad

    2015-01-01

    Acute myelopathy is increasingly being recognized as a common neurological complication of schistosomiasis. Schistosome eggs reach the spinal cord either as egg emboli or as eggs produced by ectopic worms. This leads to inflammatory reaction and granuloma formation around the eggs. Patients with spinal schistosomiasis may not have clinical evidence of schistosomiasis. The typical clinical picture is that of lumbar pain preceded by other symptoms by hours or up to 3 weeks. Patients may present with paraparesis, urinary retention or paraplegia. Definitive diagnosis of spinal cord schistosomiasis is by detection of the eggs in a spinal cord biopsy or at autopsy. However, most cases are diagnosed based on a presumptive diagnosis that depends on a suggestive clinical picture, history or evidence of active schistosomiasis and exclusion of other conditions. Investigations include stools and urine examination for schistosome eggs, blood tests, magnetic resonance imaging (MRI) and examination of the cerebrospinal fluid. Treatment of cases is mainly by praziquantel, corticosteroids, surgical intervention and rehabilitation.

  15. Spinal Cord Injury 101

    MedlinePlus Videos and Cool Tools

    ... Braingate" research? What is the status of stem-cell research? How would stem-cell therapies work in the treatment of spinal cord injuries? What does stem-cell research on animals tell us? When can we ...

  16. Spinal Muscular Atrophy

    MedlinePlus

    ... diseases that progressively destroy lower motor neurons—nerve cells in the brain stem and spinal cord that control essential voluntary muscle activity such as speaking, walking, breathing, and swallowing. ...

  17. Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.

    PubMed

    Kainz, H; Modenese, L; Lloyd, D G; Maine, S; Walsh, H P J; Carty, C P

    2016-06-14

    Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates. PMID:27139005

  18. Tensor networks from kinematic space

    NASA Astrophysics Data System (ADS)

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-01

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. We discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  19. Tensor networks from kinematic space

    DOE PAGESBeta

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-20

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry,more » obtaining a detailed agreement which includes the entwinement sector. In conclusion, we discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.« less

  20. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  1. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  2. Modeling spinal cord biomechanics

    NASA Astrophysics Data System (ADS)

    Luna, Carlos; Shah, Sameer; Cohen, Avis; Aranda-Espinoza, Helim

    2012-02-01

    Regeneration after spinal cord injury is a serious health issue and there is no treatment for ailing patients. To understand regeneration of the spinal cord we used a system where regeneration occurs naturally, such as the lamprey. In this work, we analyzed the stress response of the spinal cord to tensile loading and obtained the mechanical properties of the cord both in vitro and in vivo. Physiological measurements showed that the spinal cord is pre-stressed to a strain of 10%, and during sinusoidal swimming, there is a local strain of 5% concentrated evenly at the mid-body and caudal sections. We found that the mechanical properties are homogeneous along the body and independent of the meninges. The mechanical behavior of the spinal cord can be characterized by a non-linear viscoelastic model, described by a modulus of 20 KPa for strains up to 15% and a modulus of 0.5 MPa for strains above 15%, in agreement with experimental data. However, this model does not offer a full understanding of the behavior of the spinal cord fibers. Using polymer physics we developed a model that relates the stress response as a function of the number of fibers.

  3. Biomechanical Comparison of Spinal Fusion Methods Using Interspinous Process Compressor and Pedicle Screw Fixation System Based on Finite Element Method

    PubMed Central

    Choi, Jisoo; Kim, Sohee

    2016-01-01

    Objective To investigate the biomechanical effects of a newly proposed Interspinous Process Compressor (IPC) and compare with pedicle screw fixation at surgical and adjacent levels of lumbar spine. Methods A three dimensional finite element model of intact lumbar spine was constructed and two spinal fusion models using pedicle screw fixation system and a new type of interspinous devices, IPC, were developed. The biomechanical effects such as range of motion (ROM) and facet contact force were analyzed at surgical level (L3/4) and adjacent levels (L2/3, L4/5). In addition, the stress in adjacent intervertebral discs (D2, D4) was investigated. Results The entire results show biomechanical parameters such as ROM, facet contact force, and stress in adjacent intervertebral discs were similar between PLIF and IPC models in all motions based on the assumption that the implants were perfectly fused with the spine. Conclusion The newly proposed fusion device, IPC, had similar fusion effect at surgical level, and biomechanical effects at adjacent levels were also similar with those of pedicle screw fixation system. However, for clinical applications, real fusion effect between spinous process and hooks, duration of fusion, and influence on spinous process need to be investigated through clinical study. PMID:26962413

  4. Aero-optimum hovering kinematics.

    PubMed

    Nabawy, Mostafa R A; Crowther, William J

    2015-08-01

    Hovering flight for flapping wing vehicles requires rapid and relatively complex reciprocating movement of a wing relative to a stationary surrounding fluid. This note develops a compact analytical aero-kinematic model that can be used for optimization of flapping wing kinematics against aerodynamic criteria of effectiveness (maximum lift) and efficiency (minimum power for a given amount of lift). It can also be used to make predictions of required flapping frequency for a given geometry and basic aerodynamic parameters. The kinematic treatment is based on a consolidation of an existing formulation that allows explicit derivation of flapping velocity for complex motions whereas the aerodynamic model is based on existing quasi-steady analysis. The combined aero-kinematic model provides novel explicit analytical expressions for both lift and power of a hovering wing in a compact form that enables exploration of a rich kinematic design space. Good agreement is found between model predictions of flapping frequency and observed results for a number of insects and optimal hovering kinematics identified using the model are consistent with results from studies using higher order computational models. For efficient flight, the flapping angle should vary using a triangular profile in time leading to a constant velocity flapping motion, whereas for maximum effectiveness the shape of variation should be sinusoidal. For both cases the wing pitching motion should be rectangular such that pitch change at stroke reversal is as rapid as possible. PMID:26248884

  5. Gait in adolescent idiopathic scoliosis: kinematics and electromyographic analysis.

    PubMed

    Mahaudens, P; Banse, X; Mousny, M; Detrembleur, C

    2009-04-01

    Adolescent idiopathic scoliosis (AIS) is a progressive growth disease that affects spinal anatomy, mobility, and left-right trunk symmetry. Consequently, AIS can modify human locomotion. Very few studies have investigated a simple activity like walking in a cohort of well-defined untreated patients with scoliosis. The first goal of this study is to evaluate the effects of scoliosis and scoliosis severity on kinematic and electromyographic (EMG) gait variables compared to an able-bodied population. The second goal is to look for any asymmetry in these parameters during walking. Thirteen healthy girls and 41 females with untreated AIS, with left thoracolumbar or lumbar primary structural curves were assessed. AIS patients were divided into three clinical subgroups (group 1 < 20 degrees, group 2 between 20 and 40 degrees, and group 3 > 40 degrees). Gait analysis included synchronous bilateral kinematic and EMG measurements. The subjects walked on a treadmill at 4 km/h (comfortable speed). The tridimensional (3D) shoulder, pelvis, and lower limb motions were measured using 22 reflective markers tracked by four infrared cameras. The EMG timing activity was measured using bipolar surface electrodes on quadratus lumborum, erector spinae, gluteus medius, rectus femoris, semitendinosus, tibialis anterior, and gastrocnemius muscles. Statistical comparisons (ANOVA) were performed across groups and sides for kinematic and EMG parameters. The step length was reduced in AIS compared to normal subjects (7% less). Frontal shoulder, pelvis, and hip motion and transversal hip motion were reduced in scoliosis patients (respectively, 21, 27, 28, and 22% less). The EMG recording during walking showed that the quadratus lumborum, erector spinae, gluteus medius, and semitendinosus muscles contracted during a longer part of the stride in scoliotic patients (46% of the stride) compared with normal subjects (35% of the stride). There was no significant difference between scoliosis groups 1

  6. Imaging in spinal trauma.

    PubMed

    Van Goethem, Johan W M; Maes, Menno; Ozsarlak, Ozkan; van den Hauwe, Luc; Parizel, Paul M

    2005-03-01

    Because it may cause paralysis, injury to the spine is one of the most feared traumas, and spinal cord injury is a major cause of disability. In the USA approximately 10,000 traumatic cervical spine fractures and 4000 traumatic thoracolumbar fractures are diagnosed each year. Although the number of individuals sustaining paralysis is far less than those with moderate or severe brain injury, the socioeconomic costs are significant. Since most of the spinal trauma patients survive their injuries, almost one out of 1000 inhabitants in the USA are currently being cared for partial or complete paralysis. Little controversy exists regarding the need for accurate and emergent imaging assessment of the traumatized spine in order to evaluate spinal stability and integrity of neural elements. Because clinicians fear missing occult spine injuries, they obtain radiographs for nearly all patients who present with blunt trauma. We are influenced on one side by fear of litigation and the possible devastating medical, psychologic and financial consequences of cervical spine injury, and on the other side by pressure to reduce health care costs. A set of clinical and/or anamnestic criteria, however, can be very useful in identifying patients who have an extremely low probability of injury and who consequently have no need for imaging studies. Multidetector (or multislice) computed tomography (MDCT) is the preferred primary imaging modality in blunt spinal trauma patients who do need imaging. Not only is CT more accurate in diagnosing spinal injury, it also reduces imaging time and patient manipulation. Evidence-based research has established that MDCT improves patient outcome and saves money in comparison to plain film. This review discusses the use, advantages and disadvantages of the different imaging techniques used in spinal trauma patients and the criteria used in selecting patients who do not need imaging. Finally an overview of different types of spinal injuries is given

  7. Kinematics of the unrestrained vehicle occupants in side-impact crashes.

    PubMed

    Riley, P O; Arregui-Dalmases, C; Purtserov, S; Parent, D; Lessley, D J; Shaw, G; Crandall, J; Takayama, Shinichi; Ono, Koshiro; Kamiji, Koichi; Yasuki, Tsuyoshi

    2012-01-01

    A test series involving direct right-side impact of a moving wall on unsupported, unrestrained cadavers with no arms was undertaken to better understand human kinematics and injury mechanisms during side impact at realistic speeds. The tests conducted provided a unique opportunity for a detailed analysis of the kinematics resulting from side impact. Specifically, this study evaluated the 3-dimensional (3D) kinematics of 3 unrestrained male cadavers subjected to lateral impact by a multi-element load wall carried by a pneumatically propelled rail-mounted sled reproducing a conceptual side crash impact. Three translations and 3 rotations characterize the movement of a solid body in the space, the 6 degrees of freedom (6DoF) kinematics of 15 bone segments were obtained from the 3D marker motions and computed tomography (CT)-defined relationships between the maker array mounts and the bones. The moving wall initially made contact with the lateral aspect of the pelvis, which initiated lateral motion of the spinal segments beginning with the pelvis and moving sequentially up through the lumbar spine to the thorax. Analyzing the 6DoF motions kinematics of the ribs and sternum followed right shoulder contact with the wall. Overall thoracic motion was assessed by combining the thoracic bone segments as a single rigid body. The kinematic data presented in this research provides quantified subject responses and boundary condition interactions that are currently unavailable for lateral impact. PMID:22458795

  8. Central nervous system integration of sensorimotor signals in oral and pharyngeal structures: oropharyngeal kinematics response to recurrent laryngeal nerve lesion.

    PubMed

    Gould, Francois D H; Ohlemacher, Jocelyn; Lammers, Andrew R; Gross, Andrew; Ballester, Ashley; Fraley, Luke; German, Rebecca Z

    2016-03-01

    Safe, efficient liquid feeding in infant mammals requires the central coordination of oropharyngeal structures innervated by multiple cranial and spinal nerves. The importance of laryngeal sensation and central sensorimotor integration in this system is poorly understood. Recurrent laryngeal nerve lesion (RLN) results in increased aspiration, though the mechanism for this is unclear. This study aimed to determine the effect of unilateral RLN lesion on the motor coordination of infant liquid feeding. We hypothesized that 1) RLN lesion results in modified swallow kinematics, 2) postlesion oropharyngeal kinematics of unsafe swallows differ from those of safe swallows, and 3) nonswallowing phases of the feeding cycle show changed kinematics postlesion. We implanted radio opaque markers in infant pigs and filmed them pre- and postlesion with high-speed videofluoroscopy. Markers locations were digitized, and swallows were assessed for airway protection. RLN lesion resulted in modified kinematics of the tongue relative to the epiglottis in safe swallows. In lesioned animals, safe swallow kinematics differed from unsafe swallows. Unsafe swallow postlesion kinematics resembled prelesion safe swallows. The movement of the tongue was reduced in oral transport postlesion. Between different regions of the tongue, response to lesion was similar, and relative timing within the tongue was unchanged. RLN lesion has a pervasive effect on infant feeding kinematics, related to the efficiency of airway protection. The timing of tongue and hyolaryngeal kinematics in swallows is a crucial locus for swallow disruption. Laryngeal sensation is essential for the central coordination in feeding of oropharyngeal structures receiving motor inputs from different cranial nerves. PMID:26679618

  9. Cerebral spinal fluid (CSF) collection

    MedlinePlus

    ... neurologic disorders. These may include infections (such as meningitis) and brain or spinal cord damage. A spinal ... blood sugar), bacterial or fungal infection (such as meningitis ), tuberculosis, or certain other types of meningitis. BLOOD ...

  10. Spinal injury in a U.S. Army light observation helicopter.

    PubMed

    Shanahan, D F; Mastroianni, G R

    1984-01-01

    All accident reports involving U.S. Army OH-58 series helicopters were analyzed to determine vertical and horizontal velocity change at impact and the relationship of this kinematic data to the production of spinal injury. This analysis determined that spinal injury is related primarily to vertical velocity change at impact and is relatively independent of horizontal velocity change. The dramatic increase in the rate of spinal injury occurring just above the design sink speed of the aircraft landing gear (3.7 m/s) suggests that the fuselage and seat provide little additional impact attenuation capability above that of the gear alone. It is concluded that if this aircraft were modified to provide protection to the occupants for impacts up to 9.1 m/s (30 ft/s), approximately 80% of all spinal injury incurred in survivable accidents could be substantially mitigated. The incorporation of energy absorbing seats is recommended. PMID:6696693

  11. Spinal Subdural Haematoma

    PubMed Central

    Manish K, Kothari; Chandrakant, Shah Kunal; Abhay M, Nene

    2015-01-01

    Introduction: Spinal Subdural hematoma is a rare cause of radiculopathy and spinal cord compression syndromes. It’s early diagnosis is essential. Chronological appearance of these bleeds vary on MRI. Case Report: A 56 year old man presented with progressive left lower limb radiculopathy and paraesthesias with claudication of three days duration. MRI revealed a subdural space occupying lesion compressing the cauda equina at L5-S1 level producing a ‘Y’ shaped dural sac (Y sign), which was hyperintense on T1W imaging and hypointense to cord on T2W image. The STIR sequence showed hyperintensity to cord. There was no history of bleeding diathesis. The patient underwent decompressive durotomy and biopsy which confirmed the diagnosis. Conclusion: Spinal subdural hematoma may present with rapidly progressive neurological symptoms. MRI is the investigation of choice. The knowledge of MRI appearance with respect to the chronological stage of the bleed is essential to avoid diagnostic and hence surgical dilemma PMID:27299051

  12. Spinal injuries in children.

    PubMed

    Babcock, J L

    1975-05-01

    Spinal injuries with neurologic sequelae are a rare but catastrophic injury. Many of these injuries might be preventable through proper parent and child education, particularly in water sports and vehicles accidents. A significant number of neurologic injuries are incomplete at the time of injury and proper rescue and initial care may make the difference between life as a quadriplegic and life as a normal individual. Because of the complexity of the management of the child with spinal injuries and their relative rarity, the definitive care is best undertaken at hospitals which specialize in the care of spinal injuries. Progressive deformity of the spine, a problem unique to childhood and adolescent paralysis, is often preventable with prolonged immobilization and protection of the spine. Progressive deformities which interfere with function or result in neurologic deterioration require an aggressive surgical approach. PMID:1124228

  13. Lumbar spinal stenosis.

    PubMed Central

    Ciricillo, S F; Weinstein, P R

    1993-01-01

    Lumbar spinal stenosis, the results of congenital and degenerative constriction of the neural canal and foramina leading to lumbosacral nerve root or cauda equina compression, is a common cause of disability in middle-aged and elderly patients. Advanced neuroradiologic imaging techniques have improved our ability to localize the site of nerve root entrapment in patients presenting with neurogenic claudication or painful radiculopathy. Although conservative medical management may be successful initially, surgical decompression by wide laminectomy or an intralaminar approach should be done in patients with serious or progressive pain or neurologic dysfunction. Because the early diagnosis and treatment of lumbar spinal stenosis may prevent intractable pain and the permanent neurologic sequelae of chronic nerve root entrapment, all physicians should be aware of the different neurologic presentations and the treatment options for patients with spinal stenosis. Images PMID:8434469

  14. Spinal cord injury pain.

    PubMed

    Beric, Aleksandar

    2003-01-01

    Awareness that SCI pain is common emerged during the past decade. However, there are a number of unresolved issues. There is a need for variety of experimental models to reflect diversity of SCI pains. Current classification is not as user-friendly as it should be. More attention should be given to a condition of the spinal cord below and above the SCI lesion. A consensus for what is an optimal SCI functional assessment for patients with sensory complaints and pain should be developed. Further extensive SCI pain research is needed prior to spinal cord regeneration trials in order to be able to cope with a potential for newly developed pains that may appear during incomplete spinal cord regenerative attempts. PMID:12821403

  15. [Lumbar spinal angiolipoma].

    PubMed

    Isla, Alberto; Ortega Martinez, Rodrigo; Pérez López, Carlos; Gómez de la Riva, Alvaro; Mansilla, Beatriz

    2016-01-01

    Spinal angiolipomas are fairly infrequent benign tumours that are usually located in the epidural space of the thoracic column and represent 0.14% to 1.3% of all spinal tumours. Lumbar angiolipomas are extremely rare, representing only 9.6% of all spinal extradural angiolipomas. We report the case of a woman who complained of a lumbar pain of several months duration with no neurological focality and that had intensified in the last three days without her having had any injury or made a physical effort. The MR revealed an extradural mass L1-L2, on the posterior face of the medulla, decreasing the anteroposterior diameter of the canal. The patient symptoms improved after surgery. Total extirpation of the lesion is possible in most cases, and the prognosis is excellent even if the lesion is infiltrative. For this reason, excessively aggressive surgery is not necessary to obtain complete resection. PMID:27263067

  16. Brain and spinal tumour.

    PubMed

    Goh, C H; Lu, Y Y; Lau, B L; Oy, J; Lee, H K; Liew, D; Wong, A

    2014-12-01

    This study reviewed the epidemiology of brain and spinal tumours in Sarawak from January 2009 till December 2012. The crude incidence of brain tumour in Sarawak was 4.6 per 100,000 population/year with cumulative rate 0.5%. Meningioma was the most common brain tumour (32.3%) and followed by astrocytoma (19.4%). Only brain metastases showed a rising trend and cases were doubled in 4 years. This accounted for 15.4% and lung carcinoma was the commonest primary. Others tumour load were consistent. Primitive neuroectodermal tumour (PNET) and astrocytoma were common in paediatrics (60%). We encountered more primary spinal tumour rather than spinal metastases. Intradural schwannoma was the commonest and frequently located at thoracic level. The current healthcare system in Sarawak enables a more consolidate data collection to reflect accurate brain tumours incidence. This advantage allows subsequent future survival outcome research and benchmarking for healthcare resource planning. PMID:25934956

  17. Use of autologous growth factors in lumbar spinal fusion.

    PubMed

    Lowery, G L; Kulkarni, S; Pennisi, A E

    1999-08-01

    The results of spinal fusion, especially posteriorly above the lumbosacral junction, have been mixed. Autologous growth factor concentrate (AGF) prepared by ultraconcentration of platelets contains multiple growth factors having a chemotactic and mitogenic effect on mesenchymal stem cells and osteoblasts and may play a role in initiating bone healing. The purpose of this retrospective study is to review our results with AGF in lumbar spinal fusions. To date, AGF has been used in 39 patients having lumbar spinal fusion. The study group consisted of the first 19 consecutive cases to allow at least 6 months follow-up. The average follow-up was 13 months (range 6 to 18 months). Follow-up compliance was 91%. There were 7 men and 12 women. Average age was 52 years (range 30-72 years). Nine patients had prior back surgery. There were 8 smokers. AGF was used in posterior (n = 15) or anterior intradiscal (n = 4) fusions. AGF was used with autograft and coraline hydroxyapatite in all posterior fusions, and autograft, coral, and intradiscal spacer (carbon fiber spinal fusion cages or Synthes femoral ring) in intradiscal fusions. Posterior stabilization was used in all cases. Eight cases were single-level fusions, 6 were two-level, and 1 was a three-level fusion. Autologous iliac crest bone graft was taken in 14 cases and local autograft used in 5 cases. Posteriorly, a total of 23 levels were fused; of these, nine were at L5-S1, eight at L4-L5, five at L3-L4, and one at L2-L3. No impending pseudoarthroses were noted on plain radiographic examination at last follow-up visit. Solid fusion was confirmed in 3 patients having routine hardware removal, and in 2 patients who had surgery at an adjacent level. There was one posterior wound infection, which was managed without sequelae. When used as an adjunct to autograft, AGF offers theoretical advantages that need to be examined in controlled studies. Further study is necessary to determine whether coralline hydroxyapatite used as a

  18. Learning with the Spinal Cord.

    PubMed

    Robinson, Richard

    2015-06-01

    To what extent does the spinal cord play a role in the learning of motor tasks? A new study that simultaneously images the brain and spinal cord shows that the spinal cord is actively and independently involved in the earliest stages of motor learning. PMID:26125625

  19. Clifford Fibrations and Possible Kinematics

    NASA Astrophysics Data System (ADS)

    McRae, Alan S.

    2009-07-01

    Following Herranz and Santander [Herranz F.J., Santander M., Mem. Real Acad. Cienc. Exact. Fis. Natur. Madrid 32 (1998), 59-84, physics/9702030] we will construct homogeneous spaces based on possible kinematical algebras and groups [Bacry H., Levy-Leblond J.-M., J. Math. Phys. 9 (1967), 1605-1614] and their contractions for 2-dimensional spacetimes. Our construction is different in that it is based on a generalized Clifford fibration: Following Penrose [Penrose R., Alfred A. Knopf, Inc., New York, 2005] we will call our fibration a Clifford fibration and not a Hopf fibration, as our fibration is a geometrical construction. The simple algebraic properties of the fibration describe the geometrical properties of the kinematical algebras and groups as well as the spacetimes that are derived from them. We develop an algebraic framework that handles all possible kinematic algebras save one, the static algebra.

  20. Functional kinematics of the wrist.

    PubMed

    Rainbow, M J; Wolff, A L; Crisco, J J; Wolfe, S W

    2016-01-01

    The purpose of this article is to review past and present concepts concerning functional kinematics of the healthy and injured wrist. To provide a context for students of the wrist, we describe the progression of techniques for measuring carpal kinematics over the past century and discuss how this has influenced today's understanding of functional kinematics. Next, we provide an overview of recent developments and highlight the clinical relevance of these findings. We use these findings and recent evidence that supports the importance of coupled motion in early rehabilitation of radiocarpal injuries to develop the argument that coupled motion during functional activities is a clinically relevant outcome; therefore, clinicians should develop a framework for its dynamic assessment. This should enable a tailored and individualized approach to the treatment of carpal injuries. PMID:26568538

  1. Kinematics of KPG 390

    NASA Astrophysics Data System (ADS)

    Repetto, P.; Rosado, M.; Gabbasov, R.; Fuentes-Carrera, I.

    2010-06-01

    In this work we present scanning Fabry-Perot Hα observations of the isolated interacting galaxy pair NGC 5278/9 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. Our kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine that both components of the interacting pair are trailing spirals.

  2. Kinematic sensitivity of robot manipulators

    NASA Technical Reports Server (NTRS)

    Vuskovic, Marko I.

    1989-01-01

    Kinematic sensitivity vectors and matrices for open-loop, n degrees-of-freedom manipulators are derived. First-order sensitivity vectors are defined as partial derivatives of the manipulator's position and orientation with respect to its geometrical parameters. The four-parameter kinematic model is considered, as well as the five-parameter model in case of nominally parallel joint axes. Sensitivity vectors are expressed in terms of coordinate axes of manipulator frames. Second-order sensitivity vectors, the partial derivatives of first-order sensitivity vectors, are also considered. It is shown that second-order sensitivity vectors can be expressed as vector products of the first-order sensitivity vectors.

  3. Forelimb EMG-based trigger to control an electronic spinal bridge to enable hindlimb stepping after a complete spinal cord lesion in rats

    PubMed Central

    2012-01-01

    Background A complete spinal cord transection results in loss of all supraspinal motor control below the level of the injury. The neural circuitry in the lumbosacral spinal cord, however, can generate locomotor patterns in the hindlimbs of rats and cats with the aid of motor training, epidural stimulation and/or administration of monoaminergic agonists. We hypothesized that there are patterns of EMG signals from the forelimbs during quadrupedal locomotion that uniquely represent a signal for the “intent” to step with the hindlimbs. These observations led us to determine whether this type of “indirect” volitional control of stepping can be achieved after a complete spinal cord injury. The objective of this study was to develop an electronic bridge across the lesion of the spinal cord to facilitate hindlimb stepping after a complete mid-thoracic spinal cord injury in adult rats. Methods We developed an electronic spinal bridge that can detect specific patterns of EMG activity from the forelimb muscles to initiate electrical-enabling motor control (eEmc) of the lumbosacral spinal cord to enable quadrupedal stepping after a complete spinal cord transection in rats. A moving window detection algorithm was implemented in a small microprocessor to detect biceps brachii EMG activity bilaterally that then was used to initiate and terminate epidural stimulation in the lumbosacral spinal cord. We found dominant frequencies of 180–220 Hz in the EMG of the forelimb muscles during active periods, whereas these frequencies were between 0–10 Hz when the muscles were inactive. Results and conclusions Once the algorithm was validated to represent kinematically appropriate quadrupedal stepping, we observed that the algorithm could reliably detect, initiate, and facilitate stepping under different pharmacological conditions and at various treadmill speeds. PMID:22691460

  4. Anterior spinal cord syndrome of unknown etiology

    PubMed Central

    Klakeel, Merrine; Thompson, Justin; McDonald, Frank

    2015-01-01

    A spinal cord injury encompasses a physical insult to the spinal cord. In the case of anterior spinal cord syndrome, the insult is a vascular lesion at the anterior spinal artery. We present the cases of two 13-year-old boys with anterior spinal cord syndrome, along with a review of the anatomy and vasculature of the spinal cord and an explanation of how a lesion in the cord corresponds to anterior spinal cord syndrome. PMID:25552812

  5. Computation of trunk muscle forces, spinal loads and stability in whole-body vibration

    NASA Astrophysics Data System (ADS)

    Bazrgari, B.; Shirazi-Adl, A.; Kasra, M.

    2008-12-01

    Whole-body vibration has been indicated as a risk factor in back disorders. Proper prevention and treatment management, however, requires a sound knowledge of associated muscle forces and loads on the spine. Previous trunk model studies have either neglected or over-simplified the trunk redundancy with time-varying unknown muscle forces. Trunk stability has neither been addressed. A novel iterative dynamic kinematics-driven approach was employed to evaluate muscle forces, spinal loads and system stability in a seated subject under a random vertical base excitation with ˜±1 g peak acceleration contents. This iterative approach satisfied equations of motion in all directions/levels while accounting for the nonlinear passive resistance of the ligamentous spine. The effect of posture, co-activity in abdominal muscles and changes in buttocks stiffness were also investigated. The computed vertical accelerations were in good agreement with measurements. The input base excitation, via inertial and muscle forces, substantially influenced spinal loads and system stability. The flexed posture in sitting increased the net moment, muscle forces and passive spinal loads while improving the trunk stability. Similarly, the introduction of low to moderate antagonistic coactivity in abdominal muscles increased the passive spinal loads and improved the spinal stability. A trade-off, hence, exists between lower muscle forces and spinal loads on one hand and more stable spine on the other. Base excitations with larger peak acceleration contents substantially increase muscle forces/spinal loads and, hence, the risk of injury.

  6. Spinal Cord Injury

    MedlinePlus

    ... How much do you know about taking good care of yourself? Links to more information girlshealth glossary girlshealth.gov home http://www.girlshealth.gov/ Home Illness & disability Types of ... Spinal cord injury Read advice from Dr. Jeffrey Rabin , a pediatric rehabilitation specialist at the Children’s National Medical Center. ...

  7. Spinal and epidural anesthesia

    MedlinePlus

    ... your spinal cord. This is called the epidural space. The medicine numbs, or blocks feeling in a certain part of your body so that you cannot feel pain. The medicine begins to take effect in about 10 to 20 minutes. It works ...

  8. Lumbar Spinal Stenosis.

    PubMed

    Feeney, Richard

    2016-06-01

    Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. In reply to a question, lumbar spinal stenosis, commonly a multifactorial disease that can have profound functional consequences, is considered, along with a discussion of physical and pharmacologic treatments and quality of life. PMID:27145444

  9. Maladaptive spinal plasticity opposes spinal learning and recovery in spinal cord injury

    PubMed Central

    Ferguson, Adam R.; Huie, J. Russell; Crown, Eric D.; Baumbauer, Kyle M.; Hook, Michelle A.; Garraway, Sandra M.; Lee, Kuan H.; Hoy, Kevin C.; Grau, James W.

    2012-01-01

    Synaptic plasticity within the spinal cord has great potential to facilitate recovery of function after spinal cord injury (SCI). Spinal plasticity can be induced in an activity-dependent manner even without input from the brain after complete SCI. A mechanistic basis for these effects is provided by research demonstrating that spinal synapses have many of the same plasticity mechanisms that are known to underlie learning and memory in the brain. In addition, the lumbar spinal cord can sustain several forms of learning and memory, including limb-position training. However, not all spinal plasticity promotes recovery of function. Central sensitization of nociceptive (pain) pathways in the spinal cord may emerge in response to various noxious inputs, demonstrating that plasticity within the spinal cord may contribute to maladaptive pain states. In this review we discuss interactions between adaptive and maladaptive forms of activity-dependent plasticity in the spinal cord below the level of SCI. The literature demonstrates that activity-dependent plasticity within the spinal cord must be carefully tuned to promote adaptive spinal training. Prior work from our group has shown that stimulation that is delivered in a limb position-dependent manner or on a fixed interval can induce adaptive plasticity that promotes future spinal cord learning and reduces nociceptive hyper-reactivity. On the other hand, stimulation that is delivered in an unsynchronized fashion, such as randomized electrical stimulation or peripheral skin injuries, can generate maladaptive spinal plasticity that undermines future spinal cord learning, reduces recovery of locomotor function, and promotes nociceptive hyper-reactivity after SCI. We review these basic phenomena, how these findings relate to the broader spinal plasticity literature, discuss the cellular and molecular mechanisms, and finally discuss implications of these and other findings for improved rehabilitative therapies after SCI. PMID

  10. Kinematic support using elastic elements

    NASA Technical Reports Server (NTRS)

    Geirsson, Arni; Debra, Daniel B.

    1988-01-01

    The design of kinematic supports using elastic elements is reviewed. The two standard methods (cone, Vee and flat and three Vees) are presented and a design example involving a machine tool metrology bench is given. Design goals included thousandfold strain attenuation in the bench relative to the base when the base strains due to temperature variations and shifting loads. Space applications are also considered.

  11. Top quark mass and kinematics

    SciTech Connect

    Barberis, Emanuela; /Northeastern U.

    2006-05-01

    A summary of the results on the measurement of the Top Quark mass and the study of the kinematics of the t{bar t} system at the Tevatron collider is presented here. Results from both the CDF and D0 collaborations are reported.

  12. Kinematic Parameters of Signed Verbs

    ERIC Educational Resources Information Center

    Malaia, Evie; Wilbur, Ronnie B.; Milkovic, Marina

    2013-01-01

    Purpose: Sign language users recruit physical properties of visual motion to convey linguistic information. Research on American Sign Language (ASL) indicates that signers systematically use kinematic features (e.g., velocity, deceleration) of dominant hand motion for distinguishing specific semantic properties of verb classes in production…

  13. Kinematic analysis of the ARID manipulator

    NASA Technical Reports Server (NTRS)

    Doty, Keith L

    1992-01-01

    The kinematic structure of the ARID manipulator lends itself to simple forward and inverse kinematics analysis. The purpose of this paper is to fully document and verify an existing analysis. The symbolic software package MATHEMATICA was used to produce and verify the equations presented here. In the analysis to follow, the standard Devenit-Hartenberg kinematic parameters of the ARID were employed.

  14. Metachronal coupling between spinal neuronal networks during locomotor activity in newborn rat

    PubMed Central

    Falgairolle, Mélanie; Cazalets, Jean-René

    2007-01-01

    In the present study, we investigate spinal cord neuronal network interactions in the neonatal rat during locomotion. The behavioural and physiological relevance of metachronally propagated locomotor activity were inferred from kinematic, anatomical and in vitro electrophysiological data. Kinematic analysis of freely behaving animals indicated that there is a rhythmic sequential change in trunk curvature during the step cycle. The motoneurons innervating back and tail muscles were identified along the spinal cord using retrograde labelling. Systematic multiple recordings from ventral roots were made to determine the precise intrinsic pattern of coordination in the isolated spinal cord. During locomotor-like activity, rhythmic ventral root motor bursts propagate caudo-rostrally in the sacral and the thoracic spinal cord regions. Plotting the latency as a function of the cycle period revealed that the system adapts the intersegmental latency to the ongoing motor period in order to maintain a constant phase relationship along the spinal axis. The thoracic, lumbar and sacral regions were capable of generating right and left alternating motor bursts when isolated. Longitudinal sections of the spinal cord revealed that both the bilateral antiphase pattern observed for the sacral region with respect to the lumbar segment 2 as well as the intersegmental phase lag were due to cross-cord connections. Together, these results provide physiological evidence that the dynamic changes observed in trunk bending during locomotion are determined by the intrinsic organization of spinal cord networks and their longitudinal and transverse interactions. Similarities between this organization, and that of locomotor pattern generation in more primitive vertebrates, suggest that the circuits responsible for metachronal propagation of motor patterns during locomotion are highly conserved. PMID:17185345

  15. Exploring MaNGA's kinematic maps

    NASA Astrophysics Data System (ADS)

    Weijmans, Anne-Marie; MaNGA Team

    2016-01-01

    Different galaxy formation processes leave different imprints on the gas and stellar kinematic patterns for a galaxy. With MaNGA, we now have after one year of observations an unprecedented sample of 1400 nearby galaxies for which we can study gas and stellar kinematics in much detail, based on integral-field spectroscopy. We are measuring kinematic quantities such as LambdaR (angular momentum) and their (possible) correlations with other galaxy properties such as mass, morphology and environment. By quantifying the kinematic (sub)structures in velocity and dispersion maps, we will construct a kinematic galaxy classification that can be linked to their formation processes.

  16. Aspergillus spinal epidural abscess

    SciTech Connect

    Byrd, B.F. III; Weiner, M.H.; McGee, Z.A.

    1982-12-17

    A spinal epidural abscess developed in a renal transplant recipient; results of a serum radioimmunoassay for Aspergillus antigen were positive. Laminectomy disclosed an abscess of the L4-5 interspace and L-5 vertebral body that contained hyphal forms and from which Aspergillus species was cultured. Serum Aspergillus antigen radioimmunoassay may be a valuable, specific early diagnostic test when systemic aspergillosis is a consideration in an immunosuppressed host.

  17. Contact kinematics of biomimetic scales

    SciTech Connect

    Ghosh, Ranajay; Ebrahimi, Hamid; Vaziri, Ashkan

    2014-12-08

    Dermal scales, prevalent across biological groups, considerably boost survival by providing multifunctional advantages. Here, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element (FE) analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate.

  18. Contact kinematics of biomimetic scales

    NASA Astrophysics Data System (ADS)

    Ghosh, Ranajay; Ebrahimi, Hamid; Vaziri, Ashkan

    2014-12-01

    Dermal scales, prevalent across biological groups, considerably boost survival by providing multifunctional advantages. Here, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element (FE) analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate.

  19. Kinematic Fitting of Detached Vertices

    SciTech Connect

    Paul Mattione

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  20. Measurement of reed valve kinematics

    NASA Astrophysics Data System (ADS)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  1. Kinematics of planetary nebulae. II

    NASA Astrophysics Data System (ADS)

    Purgathofer, A.; Perinotto, M.

    1981-08-01

    In a program of study of radial velocities of planetary nebulae, 84 spectra of eight planetary nebulae in the direction of the galactic anticenter have been obtained at the L. Figl Observatory near Vienna with an image tube spectrograph giving a reciprocal dispersion of 26 A/mm. With this material, the kinematical behavior of the objects was studied, and it is shown that most of them deviate significantly from circular motion in the Galaxy.

  2. Degenerative Spinal Deformity.

    PubMed

    Ailon, Tamir; Smith, Justin S; Shaffrey, Christopher I; Lenke, Lawrence G; Brodke, Darrel; Harrop, James S; Fehlings, Michael; Ames, Christopher P

    2015-10-01

    Degenerative spinal deformity afflicts a significant portion of the elderly and is increasing in prevalence. Recent evidence has revealed sagittal plane malalignment to be a key driver of pain and disability in this population and has led to a significant shift toward a more evidence-based management paradigm. In this narrative review, we review the recent literature on the epidemiology, evaluation, management, and outcomes of degenerative adult spinal deformity (ASD). ASD is increasing in prevalence in North America due to an aging population and demographic shifts. It results from cumulative degenerative changes focused in the intervertebral discs and facet joints that occur asymmetrically to produce deformity. Deformity correction focuses on restoration of global alignment, especially in the sagittal plane, and decompression of the neural elements. General realignment goals have been established, including sagittal vertical axis <50 mm, pelvic tilt <22°, and lumbopelvic mismatch <±9°; however, these should be tailored to the patient. Operative management, in carefully selected patients, yields satisfactory outcomes that appear to be superior to nonoperative strategies. ASD is characterized by malalignment in the sagittal and/or coronal plane and, in adults, presents with pain and disability. Nonoperative management is recommended for patients with mild, nonprogressive symptoms; however, evidence of its efficacy is limited. Surgery aims to restore global spinal alignment, decompress neural elements, and achieve fusion with minimal complications. The surgical approach should balance the desired correction with the increased risk of more aggressive maneuvers. In well-selected patients, surgery yields excellent outcomes. PMID:26378361

  3. FAQs about Spinal Cord Injury (SCI)

    MedlinePlus

    ... Website Managing Bowel Function After Spinal Cord Injury Resilience, Depression and Bouncing Back after SCI Getting to ... a “complete” and “incomplete” spinal cord injury? What recovery is expected following spinal cord injury? Where is ...

  4. Of cilium and flagellum kinematics

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Promode R.; Hansen, Joshua C.

    2009-11-01

    The kinematics of propulsion of small animals such as paramecium and spermatozoa is considered. Larger scale models of the cilium and flagellum have been built and a four-motor apparatus has been constructed to reproduce their known periodic motions. The cilium model has transverse deformational ability in one plane only, while the flagellum model has such ability in two planes. When the flagellum model is given a push-pull in one diametral plane, instead of transverse deflection in one plane, it forms a coil. Berg & Anderson's postulation (Nature 245 1973) that a flagellum rotates, is recalled. The kinematics of cilia of paramecium, of the whipping motion of the spermatozoa flagella, and of the flapping motion (rolling and pitching) of the pectoral fins of much larger animals such penguins, have been reproduced in the same basic paramecium apparatus. The results suggest that each of the tiny individual paramecium propulsors have the intrinsic dormant kinematic and structural building blocks to optimize into higher Reynolds number propulsors. A synthetic hypothesis on how small might have become large is animated.

  5. Kinematic top analyses at CDF

    SciTech Connect

    Cobal-Grassman, M.; CDF Collaboration

    1996-01-01

    We present an update of the top quark analysis using kinematic techniques in {rho}{ovr string {rho}} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We reported before on a study which used 19.3 pb{sup -1} of data from the 1992-93 collider run, but now we use a larger data sample of 67 pb{sup -1}. First, we analyze the total transverse energy of the hard collision in W+{ge}3 jet events, showing the likely presence of a t{ovr string t} component in the event sample. Next, we compare in more detail the kinematic structure of W+{ge}3 jet events with expectations for top pair production and with background processes, predominantly direct W+ jet production. We again find W+{ge}3 jet events which cannot be explained in terms of background, but show kinematic features as expected from top. These events also show evidence for beauty quarks. The findings confirm the observation of top events made earlier in the data of the 1992-93 collider run.

  6. Kinematic models of cometary comae

    NASA Astrophysics Data System (ADS)

    Tacconi-Garman, Lowell Evan

    As a first step towards understanding the kinematics of cometary comae, an analysis was undertaken of the 18-cm OH lines in comets. This work builds on past OH excitation and kinematic studies to meld them into a complete and self-consistent model for a cometary coma. The kinematics were modeled via the vectorial formalism and the powerful Monte Carlo technique was used in an effort to reproduce the high sensitivity, high spectral resolution 18-cm OH line profiles of Comets Halley, Giacobini-Zinner, Hartley-Good, Thiele, and Wilson which were obtained at the 43 meter telescope of the National Radio Astronomy Observatory at Green Bank, West Virginia. For the first time a zeroth order A-doublet quenching correction was applied to the 18-cm data and the long standing UV/radio gas production rate disparity was accounted for. Gas expansion velocities and coma anisotropies were derived from observations covering a wide range of heliocentric distances and gas production rates. The inferred ratio of dayside gas emission to nightside gas emission for all comets in this study, except P/Giacobini-Zinner, is approx. two. This value is consistent with that derived from in situ observations of the neutral gas in the coma of Comet Halley and is independent of both gas productivity and heliocentric distance. For P/Giacobini-Zinner, anomalously high gas outflow anisotropies were inferred for which there is no clear explanation.

  7. Lumbar spinal surgery - series (image)

    MedlinePlus

    ... of bones (vertebrae) separated by soft cushions (intervertebral discs). ... Lumbar (lower back) spine disease is usually caused by herniated ... bodies (osteophytes), which compress spinal nerves, trauma, and ...

  8. 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

  9. Spinal lipomas in children.

    PubMed

    Xenos, C; Sgouros, S; Walsh, R; Hockley, A

    2000-06-01

    Spinal cord lipomas are a common cause of cord tethering that can lead to progressive neurological defects. The role of prophylactic surgery for spinal lipomas has recently been questioned. Between 1985 and 1999, 59 children underwent a total of 69 surgical procedures at the Birmingham Children's Hospital in Birmingham, UK. The spinal lipomas were classified into: 18 terminal, 17 transitional, 6 dorsal and 18 filum lipomas - including 12 who had a typical thickened filum terminale. At the first operation, 19 patients (32%) were asymptomatic, and 40 patients (68%) presented with symptoms. Surgical indications in the asymptomatic group included the presence of a dermal sinus tract or syrinx. Prophylactic surgery was undertaken in selected cases. The mean total follow-up for the group since the first surgical procedure was 61.8 months (range: 7.0-203.0 months). In the asymptomatic group, 26% of the patients had late neurological deterioration. Of the 14 patients with asymptomatic conus lipomas, 3 (21%) developed sphincter dysfunction and motor problems at long-term follow-up. In the symptomatic group, 68% improved, 20% remained unchanged, and 12% had late neurological deterioration. None of the 18 patients with symptomatic filum lipoma deteriorated postoperatively. However, 39% had bladder dysfunction, 54% had neuro-orthopaedic deformity, and only 15% returned to overall normal function at latest follow-up. Of the 27 patients with symptomatic conus lipomas, 67% improved, 15% remained stable, and 18% had late neurological deterioration. However, 74% had bladder dysfunction, 67% had neuro-orthopaedic deformity, and 45% had motor problems at long-term follow-up. Spinal lipomas can cause progressive neurological deficits irrespective of spinal untethering surgery. This study demonstrates that filum and conus lipomas have similar clinical presentation, but differ in their outcome following surgery. Filum lipomas are 'benign', for which surgery is safe and effective. Conus

  10. The history of spinal biomechanics.

    PubMed

    Sanan, A; Rengachary, S S

    1996-10-01

    The history of spinal biomechanics has its origins in antiquity. The Edwin Smith surgical papyrus, an Egyptian document written in the 17th century BC, described the difference between cervical sprain, fracture, and fracture-dislocation. By the time of Hippocrates (4th century BC), physical means such as traction or local pressure were being used to correct spinal deformities but the treatments were based on only a rudimentary knowledge of spinal biomechanics. The Renaissance produced the first serious attempts at understanding spinal biomechanics. Leonardo da Vinci (1452-1519) accurately described the anatomy of the spine and was perhaps the first to investigate spinal stability. The first comprehensive treatise on biomechanics, De Motu Animalium, was published by Giovanni Borelli in 1680, and it contained the first analysis of weight bearing by the spine. In this regard, Borelli can be considered the "Father of Spinal Biomechanics." By the end of the 19th century, the basic biomechanical concepts of spinal alignment and immobilization were well entrenched as therapies for spinal cord injury. Further anatomic delineation of spinal stability was sparked by the anatomic analyses of judicial hangings by Wood-Jones in 1913. By the 1960s, a two-column model of the spine was proposed by Holdsworth. The modern concept of Denis' three-column model of the spine is supported by more sophisticated testing of cadaver spines in modern biomechanical laboratories. The modern explosion of spinal instrumentation stems from a deeper understanding of the load-bearing structures of the spinal column. PMID:8880756

  11. Adjustment to Spinal Cord Injury

    MedlinePlus

    ... of injury are alive and easily get educational information on the Internet. Web happy. sites such as the National Spinal Cord Injury Association (www.spinalcord.org) and SPINAL CORD Injury ♦ “Because of my injury, it is now impossible for me Information Network (www.spinalcord.uab.edu) have to ever ...

  12. Imaging modalities in spinal disorders

    SciTech Connect

    Kricun, M.E.

    1986-01-01

    This book provides an approach to the various imaging modalities used to view the spine. It discusses the indications, limitations and practical use of each in the diagnosis, work-up and staging of various spinal disorders, and compares each of them in various clinical settings. Topics covered include low back pain syndrome, disk disease, spinal cord lesions, congenital abnormalities, and trauma.

  13. Spinal Injury Rehabilitation in Singapore.

    ERIC Educational Resources Information Center

    Yen, H. L.; Chua, K.; Chan, W.

    1998-01-01

    This study reviewed 231 cases of spinal cord injury treated in Singapore. Data on demographic characteristics, common causes (mostly falls and traffic accidents), types of spinal damage, and outcomes are reported. Following rehabilitation, 68 patients were able to ambulate independently and 45 patients achieved independence in activities of daily…

  14. Assessment of spinal pain.

    PubMed

    Braun, J; Baraliakos, X; Regel, A; Kiltz, U

    2014-12-01

    Spinal pain or back pain is a very common symptom that can have many reasons. The most studied location is low back pain, and it is considered to be nonspecific in the majority of cases. Only a small proportion of patients have axial inflammation as the major cause of their back complaints with chronic inflammatory back pain (IBP) as the most prominent clinical feature of spondyloarthritis (SpA). The recognition of IBP and patients with axial spondyloarthritis (axSpA) is challenging in primary care, and it is important to further facilitate the early diagnosis of SpA. Proposals for improving the referral of patients with a possible diagnosis of axSpA include clinical parameters, human leukocyte antigen (HLA) B27, and imaging parameters. Imaging is crucial for the visualization, objective validation, and understanding of back pain. Numerous diseases such as degenerative disk disease, degenerative changes in the intervertebral (facet) joints and the associated ligaments, spinal instability, herniation of the intervertebral disk, and spinal stenosis have to be differentiated in interpreting imaging of the spine. The sacroiliac joints and the spine are of major importance for the diagnosis and classification of axSpA. Conventional radiographs and magnetic resonance imaging (MRI) are the most important imaging technologies for visualization of structural changes such as syndesmophytes and axial inflammation such as sacroiliitis and spondylitis. The pathogenesis of axSpA is largely genetically determined. HLA B27 has the strongest contribution to the total genetic burden, but other major contributors such as endoplasmic reticulum aminopeptidase (ERAP)-1 and interleukin (IL)-23R have also been identified. PMID:26096091

  15. Spinal tumors in children.

    PubMed

    Binning, Mandy; Klimo, Paul; Gluf, Wayne; Goumnerova, Liliana

    2007-10-01

    Pediatric spine tumors encompass a diverse group of pathologic diagnoses that differ markedly based on the location and age of the child. Children can be affected by primary and metastatic tumors, making the differential diagnosis and treatment options extensive. This article discusses the features of spinal tumors in children based primarily on location: extradural, intradural-extramedullary, and intramedullary tumors. Because this article deals with such a broad topic, detailed descriptions and outcomes of surgical and nonsurgical treatments for each particular tumor are limited. Rather, the key clinical, diagnostic, and therapeutic features of each tumor are discussed. PMID:17991588

  16. Kinematic correction for roller skewing

    NASA Technical Reports Server (NTRS)

    Savage, M.; Loewenthal, S. H.

    1980-01-01

    A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to product changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

  17. Dynamic Compression of the Spinal Cord by Paraspinal Muscles following Cervical Laminectomy: Diagnosis Using Flexion-Extension MRI.

    PubMed

    Evans, Linton T; Lollis, S Scott

    2015-01-01

    Introduction. Flexion-extension, or kinematic, MRI has been used to identify dynamic spondylotic spinal cord compression not seen with traditional static MRI. The use of kinematic MRI to diagnose postoperative complications, specifically dynamic compression, is not as well documented. The authors describe a case of dynamic spinal cord compression by the paraspinal muscles causing worsening myelopathy following cervical laminectomy. This was only diagnosed with flexion-extension MRI. Methods. The patient was a 90-year-old male presenting to the neurosurgery clinic with functional decline and cervical spondylotic myelopathy. Results. A multilevel laminectomy was performed. Following surgery the patient had progressive weakness and worsening myelopathy. No active cord compression was seen on multiple MRIs obtained in a neutral position, and flexion-extension X-rays did not show instability. A kinematic MRI demonstrated dynamic compression of the spinal cord only during neck extension, by the paraspinal muscles. To relieve the compression, the patient underwent an instrumented fusion, with cross-links used to buttress the paraspinal muscles away from the cord. This resulted in neurologic improvement. Conclusions. We describe a novel case of spinal cord compression by paraspinal muscles following cervical laminectomy. In individuals with persistent myelopathy or delayed neurologic decline following posterior decompression, flexion-extension MRI may prove useful in diagnosing this potential complication. PMID:25984378

  18. Dynamic Compression of the Spinal Cord by Paraspinal Muscles following Cervical Laminectomy: Diagnosis Using Flexion-Extension MRI

    PubMed Central

    Evans, Linton T.; Lollis, S. Scott

    2015-01-01

    Introduction. Flexion-extension, or kinematic, MRI has been used to identify dynamic spondylotic spinal cord compression not seen with traditional static MRI. The use of kinematic MRI to diagnose postoperative complications, specifically dynamic compression, is not as well documented. The authors describe a case of dynamic spinal cord compression by the paraspinal muscles causing worsening myelopathy following cervical laminectomy. This was only diagnosed with flexion-extension MRI. Methods. The patient was a 90-year-old male presenting to the neurosurgery clinic with functional decline and cervical spondylotic myelopathy. Results. A multilevel laminectomy was performed. Following surgery the patient had progressive weakness and worsening myelopathy. No active cord compression was seen on multiple MRIs obtained in a neutral position, and flexion-extension X-rays did not show instability. A kinematic MRI demonstrated dynamic compression of the spinal cord only during neck extension, by the paraspinal muscles. To relieve the compression, the patient underwent an instrumented fusion, with cross-links used to buttress the paraspinal muscles away from the cord. This resulted in neurologic improvement. Conclusions. We describe a novel case of spinal cord compression by paraspinal muscles following cervical laminectomy. In individuals with persistent myelopathy or delayed neurologic decline following posterior decompression, flexion-extension MRI may prove useful in diagnosing this potential complication. PMID:25984378

  19. A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs

    PubMed Central

    Swaminathan, Ramesh; Williams, Jonathan M.; Jones, Michael D.; Theobald, Peter S.

    2016-01-01

    ABSTRACT Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario. PMID:26375051

  20. A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs.

    PubMed

    Swaminathan, Ramesh; Williams, Jonathan M; Jones, Michael D; Theobald, Peter S

    2016-01-01

    Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario. PMID:26375051

  1. Finite rotation and nonlinear beam kinematics

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.

    1987-01-01

    Standard means of representing finite rotation in rigid-body kinematics, including orientation angles, Euler parameters, and Rodrigues parameters, are reviewed and compared. General kinematical relations for a beam theory that treats arbitrarily large rotation are then presented. The standard methods of representing finite rotations are applied to these kinematical expressions, and comparison is made among the standard methods and additional methods found in the literature, such as quasi-coordinates and linear combinations of projection angles. The method of Rodrigues parameters is shown to stand out for both its simplicity and generality when applied to beam kinematics, a result that is really missing from the literature.

  2. Basic concepts of kinematic-wave models

    USGS Publications Warehouse

    Miller, J.E.

    1984-01-01

    The kinematic-wave model is one of a number of approximations of the dynamic-wave model. The dynamic-wave model describes one-dimensional shallow-water waves (unsteady, gradually varied, open-channel flow). The report provides a basic reference on the theory and application of kinematic-wave models and describes the limitations of the model in relation to the other approximations of the dynamic-wave model. In the kinematic-wave approximation, a number of the terms in the equation of motion are assumed to be insignificant. The equation of motion is replaced by an equation describing uniform flow. Thus, the kinematic-wave model is described by the continuity equation and a uniform flow equation such as the well-known Chezy or Manning formulas. Kinematic-wave models are applicable to overland flow where lateral inflow is continuously added and is a large part of the total flow. For channel-routing applications, the kinematic-wave model always predicts a steeper wave with less dispersion and attenuation than actually occurs. The effect of the accumulation of errors in the kinematic-wave model shows that the approximations made in the development of the kinematic-wave equations are not generally justified for most channel-routing applications. Modified flow-routing models can be used which help to stop the accumulation of error that occurs when the kinematic-wave model is applied. (USGS)

  3. Juxtafacet Spinal Synovial Cysts

    PubMed Central

    2016-01-01

    Study Design This was a retrospective study. Purpose To study the surgical outcome of synovial cysts of the lumbar spine through posterior laminectomy in combination with transpedicular screw fixation. Overview of Literature Synovial cysts of the lumbar spine contribute significantly to narrowing of the spinal canal and lateral thecal sac and nerve root compression. Cysts form as a result of arthrotic disruption of the facet joint, leading to degenerative spondylolisthesis in up to 40% of patients. Methods Retrospective data from 6 patients, treated during the period of March 2007 to February 2011, were analyzed. All preoperative and postoperative manifestations, extension/flexion radiographs, magnetic resonance imaging, and computed tomography records were reviewed. All underwent surgery for synovial cysts with excision and decompression combined with posterior fixation. The result of surgery was evaluated with Macnab's classification. An excellent or good outcome was considered as satisfactory. Japanese Orthopedic Association Scale was used for evaluation of back pain. Results All patients included in this study had excellent outcomes as regarding to improvement of all preoperative manifestations and returning to normal daily activities. Only 2 cases developed postoperative transient cerebro-spinal fluid leak and were treated conservatively and improved during the follow up period. Conclusions Although this study included a small number of cases and we could not have statistically significant results, the good outcome of decompression of synovial cysts combined with posterior fixation and fusion encouraged us to recommend this approach for patients with juxtafacet synovial cysts. PMID:26949457

  4. Ballistic representation for kinematic access

    NASA Astrophysics Data System (ADS)

    Alfano, Salvatore

    2011-01-01

    This work uses simple two-body orbital dynamics to initially determine the kinematic access for a ballistic vehicle. Primarily this analysis was developed to assess when a rocket body might conjunct with an orbiting satellite platform. A family of access opportunities can be represented as a volume for a specific rocket relative to its launch platform. Alternately, the opportunities can be represented as a geographical footprint relative to aircraft or satellite position that encompasses all possible launcher locations for a specific rocket. A thrusting rocket is treated as a ballistic vehicle that receives all its energy at launch and follows a coasting trajectory. To do so, the rocket's burnout energy is used to find its equivalent initial velocity for a given launcher's altitude. Three kinematic access solutions are then found that account for spherical Earth rotation. One solution finds the maximum range for an ascent-only trajectory while another solution accommodates a descending trajectory. In addition, the ascent engagement for the descending trajectory is used to depict a rapid access scenario. These preliminary solutions are formulated to address ground-, sea-, or air-launched vehicles.

  5. Kinematic features of wheelchair propulsion.

    PubMed

    Sanderson, D J; Sommer, H J

    1985-01-01

    Three male paraplegics volunteered to push their wheelchairs on a motor driven treadmill, for a total of 80 min each, at a work rate of 60-65% of their VO2 maximum, determined on an earlier test session. At 20 min intervals 16 mm high-speed film of the subjects was taken for three consecutive push cycles. The digitized film was used to compute the angular kinematics of the shoulder and elbow joints, the variations in the position of the trunk (as measured by a marker on the neck) and hand relative to the axle of the rear wheel. There were no intrasubject variations over the 80 min testing period for any of the recorded variables. This was interpreted as implying that at that work rate, fatigue was not exhibited as variations in the kinematics of movement. There were considerable differences between the style of one subject when compared to the other two over all the trials of each subject. This variation in style was most obvious in subject number PT who had a pumping style of push and recovery whereas subjects CA and GW employed a more continuous circular motion. The differences in the amount of forward lean of each subject were related to residual muscle strength. The discussion centered on the influence of the different styles on performance. PMID:4030799

  6. Kinematic design NC optical generator

    NASA Astrophysics Data System (ADS)

    Kuhn, William P.

    1989-08-01

    The purpose of this research was to design a low cost, versatile, 3-axis numerical control aspheric generator using all rotary motions. In addition, the generator was to have the capability of grinding glass, metals and ceramics and the ability to generate off axis or non-rotationally symmetric aspherics. The research carried out during this study was a review of various methods of implementing 3 axis motion using all rotary bearings. Traditional orthogonal axis methods of achieving this motion were found lacking in accuracy and very costly. The study then turned to a generator based on kinematic design with a minimum number of constraints to the rotary motions. The results of this research showed that the kinematic design met or exceeded all the proposed goals for this study. The design has a minimum number of components and depends for its accuracy only on the lengths of the two actuators controlling the grinding wheel position. The rotary motion joints are all spherical ball joints except for one that is a flexure pivot. The proposed generator uses commercially available components and has few custom parts to keep the cost down. Special software allows the easy fabrication of non-rotationally symmetric optics and a large grinding wheel radius minimizes mid spatial frequency surface errors and roughness.

  7. A physiologically based hypothesis for learning proprioception and in approximating inverse kinematics.

    PubMed

    Simkins, Matt

    2016-05-01

    A long-standing problem in muscle control is the "curse of dimensionality". In part, this problem relates to the fact that coordinated movement is only achieved through the simultaneous contraction and extension of multitude muscles to specific lengths. Couched in robotics terms, the problem includes the determination of forward and inverse kinematics. Of the many neurophysiological discoveries in cortex is the existence of position gradients. Geometrically, position gradients are described by planes in Euclidean space whereby neuronal activity increases as the hand approaches locations that lie in a plane. This work demonstrates that position gradients, when coupled with known physiology in the spinal cord, allows for a way to approximate proprioception (forward kinematics) and to specify muscle lengths for goal-directed postures (inverse kinematics). Moreover, position gradients provide a means to learn and adjust kinematics as animals learn to move and grow. This hypothesis is demonstrated using computer simulation of a human arm. Finally, experimental predictions are described that might confirm or falsify the hypothesis. PMID:27225625

  8. Attitudes Towards Individuals with Spinal Cord Injuries

    ERIC Educational Resources Information Center

    Conway, Cassandra Sligh D.; Gooden, Randy; Nowell, Jennifer; Wilson, Navodda

    2010-01-01

    This paper will shed light on the lives of persons with spinal cord injuries by revealing the literature on spinal cord injuries that focuses on research that can shed light on attitudes towards persons with spinal cord injuries. The background literature related to incidences, the definition of spinal cord injury, and vocational opportunities are…

  9. Spinal Plasticity following Intermittent Hypoxia: Implications for Spinal Injury

    PubMed Central

    Dale-Nagle, Erica A.; Hoffman, Michael S.; MacFarlane, Peter M.; Satriotomo, Irawan; Lovett-Barr, Mary Rachael; Vinit, Stéphane; Mitchell, Gordon S.

    2011-01-01

    Plasticity is a fundamental property of the neural system controlling breathing. One frequently studied model of respiratory plasticity is long-term facilitation of phrenic motor output (pLTF) following acute intermittent hypoxia (AIH). pLTF arises from spinal plasticity, increasing respiratory motor output through a mechanism that requires new synthesis of brain derived neurotrophic factor (BDNF), activation of its high affinity receptor, tropomyosin-related kinase B (TrkB) and extracellular-related kinase (ERK) mitogen-activated protein (MAP) kinase signaling in or near phrenic motor neurons. Since intermittent hypoxia induces spinal plasticity, we are exploring the potential to harness repetitive AIH as a means of inducing functional recovery in conditions causing respiratory insufficiency, such as cervical spinal injury. Since repetitive AIH induces phenotypic plasticity in respiratory and motor neurons, it may restore respiratory motor function in patients with incomplete spinal injury. PMID:20536940

  10. Kinematic Event Patterns in Speech: Special Problems.

    ERIC Educational Resources Information Center

    Westbury, John R.; Severson, Elizabeth J.; Lindstrom, Mary J.

    2000-01-01

    Results from a new analysis of synchronous acoustic and fleshpoint-kinematic data, recorded from 53 normal young-adult speakers of American English, are reported. The kinematic data represent speech-related actions of the tongue blade and dorsum, both lips, and the mandible, during the test words, "special" and "problem," and were drawn from an…

  11. Kinematics of the free throw in basketball

    NASA Astrophysics Data System (ADS)

    Tan, A.; Miller, G.

    1981-06-01

    The kinematics of the two basic styles of free throw in basketball are discussed. It is shown that from a purely kinematic and trajectory point of view, the overhand push shot is preferable to the underhand loop shot. The advantages of the underhand shot lie in the actual execution of the shot.

  12. Simulation in spinal diseases.

    PubMed

    Aso Escario, José; Martínez Quiñones, José Vicente; Aso Vizán, Alberto; Arregui Calvo, Ricardo; Bernal Lafuente, Marta; Alcázar Crevillén, Andrés

    2014-01-01

    Simulation is frequent in spinal disease, resulting in problems for specialists like Orthopedic Surgeons, Neurosurgeons, Reumathologists, etc. Simulation requires demonstration of the intentional production of false or exaggerated symptoms following an external incentive. The clinician has difficulties in demonstrating these criteria, resulting in misdiagnosis of simulation or misinterpretation of the normal patient as a simulator, with the possibility of iatrogenic distress and litigation. We review simulation-related problems in spine, proposing a terminological, as well as a diagnostic strategy including clinical and complementary diagnosis, as a way to avoid misinterpretation and minimize the iatrogenic distress and liability Based on the clinical-Forensic author's expertise, the literature is analyzed and the terminology readdressed to develop new terms (inconsistences, incongruences, discrepancies and contradictions). Clinical semiology and complementary test are adapted to the new scenario. Diagnostic strategy relies on anamnesis, clinical and complementary tests, adapting them to a uniform terminology with clear meaning of signs and symptoms. PMID:24913963

  13. Epidural Cystic Spinal Meningioma

    PubMed Central

    Zhang, Ji; Chen, Zheng-he; Wang, Zi-feng; Sun, Peng; Jin, Jie-tian; Zhang, Xiang-heng; Zhao, Yi-ying; Wang, Jian; Mou, Yong-gao; Chen, Zhong-ping

    2016-01-01

    Abstract Cystic spinal meningioma (CSM) is an uncommon meningioma variant. Extradural CSMs are particularly rare and difficult to distinguish from other intraaxial tumors. This study presents a case of a 36-year-old woman with intraspinal extradual CSM at the thoracolumbar spine. She experienced persistent weakness, progressive numbness, and sensory disturbance in the right lower limb. Magnetic resonance imaging (MRI) of the patient revealed an irregular cystic mass at the thoracic 11 to lumbar 3 levels dorsally. This case was misdiagnosed as other neoplasms prior to surgery because of the atypical radiographic features and location of the tumor. Extradural CSMs should be considered in the differential diagnosis of intraspinal extradural cystic neoplasms. Complete removal of cystic wall provides an optimal outcome, rendering the lesion curable. PMID:26986119

  14. Bayesian kinematic earthquake source models

    NASA Astrophysics Data System (ADS)

    Minson, S. E.; Simons, M.; Beck, J. L.; Genrich, J. F.; Galetzka, J. E.; Chowdhury, F.; Owen, S. E.; Webb, F.; Comte, D.; Glass, B.; Leiva, C.; Ortega, F. H.

    2009-12-01

    Most coseismic, postseismic, and interseismic slip models are based on highly regularized optimizations which yield one solution which satisfies the data given a particular set of regularizing constraints. This regularization hampers our ability to answer basic questions such as whether seismic and aseismic slip overlap or instead rupture separate portions of the fault zone. We present a Bayesian methodology for generating kinematic earthquake source models with a focus on large subduction zone earthquakes. Unlike classical optimization approaches, Bayesian techniques sample the ensemble of all acceptable models presented as an a posteriori probability density function (PDF), and thus we can explore the entire solution space to determine, for example, which model parameters are well determined and which are not, or what is the likelihood that two slip distributions overlap in space. Bayesian sampling also has the advantage that all a priori knowledge of the source process can be used to mold the a posteriori ensemble of models. Although very powerful, Bayesian methods have up to now been of limited use in geophysical modeling because they are only computationally feasible for problems with a small number of free parameters due to what is called the "curse of dimensionality." However, our methodology can successfully sample solution spaces of many hundreds of parameters, which is sufficient to produce finite fault kinematic earthquake models. Our algorithm is a modification of the tempered Markov chain Monte Carlo (tempered MCMC or TMCMC) method. In our algorithm, we sample a "tempered" a posteriori PDF using many MCMC simulations running in parallel and evolutionary computation in which models which fit the data poorly are preferentially eliminated in favor of models which better predict the data. We present results for both synthetic test problems as well as for the 2007 Mw 7.8 Tocopilla, Chile earthquake, the latter of which is constrained by InSAR, local high

  15. Efficient kinematics for jet-propelled swimming

    NASA Astrophysics Data System (ADS)

    Alben, Silas; Miller, Laura; Peng, Jifeng

    2013-11-01

    We use vortex sheet and viscous simulations and an analytical model to search for efficient jet-propelled swimming kinematics at large Reynolds numbers (1000 and above). We prescribe different power-law kinematics for the bell contraction and expansion. In the simulations, two types of efficient kinematics are found: a bell radius velocity which is a nearly linear function of time, and a ``burst-and-coast'' kinematics. The analytical model studies the contraction phase only, and finds that the efficiency-optimizing kinematics transition from a nearly linear bell radius velocity (similar to the numerics) for small-to-moderate output power to an exponentially-decaying bell radius velocity for large output power.

  16. On the kinematic analysis of robotic mechanisms

    SciTech Connect

    Nielsen, J.; Roth, B.

    1999-12-01

    The kinematic analyses, of manipulators and other robotic devices composed of mechanical links, usually depend on the solution of sets of nonlinear equations. There are a variety of both numerical and algebraic techniques available to solve such systems of equations and to give bounds on the number of solutions. These solution methods have also led to an understanding of how special choices of the various structural parameters of a mechanism influence the number of solutions inherent to the kinematic geometry of a given structure. In this paper, results from studying the kinematic geometry of such systems are reviewed, and the three most useful solution techniques are summarized. The solution techniques are polynomial continuation, Groebner bases, and elimination. The authors then discuss the results that have been obtained with these techniques in the solution of two basic problems, namely, the inverse kinematics for serial-chain manipulators, and the direct kinematics of in-parallel platform devices.

  17. Kinematic analysis following implantation of the PRESTIGE LP

    PubMed Central

    Kowalczyk, Izabela; Chaudhary, Navjot; Duggal, Neil

    2013-01-01

    Background The clinical success of cervical arthroplasty hinges on the ability to preserve or improve the biomechanics of the functional spinal unit. The purpose of this study was to conduct a radiologic assessment of kinematic parameters preimplantation and postimplantation of the PRESTIGE LP Cervical Disc System (Medtronic, Memphis, Tennessee). Methods A total of 120 radiographs of 20 patients following single-level implantation of the PRESTIGE LP were retrospectively reviewed. Static and dynamic radiologic assessments were performed before surgery and at 1 year postoperation. Kinematic parameters including range of motion (ROM), horizontal translation, center of rotation (COR X, Y), anterior disc height and posterior disc height, and disc angle and shell angle were assessed for each spinal level using quantitative motion analysis software. Clinical outcomes were assessed using the short form health survey physical component scores and mental component scores. Results The mean physical component scores and mental component scores of the short form health survey (SF-36) improved significantly following surgery. At 1 year postoperation, ROM, translation, and COR X were preserved. The COR Y shifted superiorly from 3.17 ± 2.08 mm preoperation to 0.98 ± 2.23 mm postoperation (P < .001). The anterior disc height and posterior disc height were significantly increased following surgery (3.97 ± 1.01 to 4.78 ± 1.11 mm and 3.04 ± 0.69 to 3.66 ± 0.61 mm, respectively; P < .01). The preoperative disc angle was 3.32° ± 2.92° and the postoperative shell angle was 1.11° ± 4.29°, with a mean change of −2.22° ± 4.63° (P < .05). Conclusions The PRESTIGE LP maintained preoperative ROM, translation, and COR X values. The postoperative COR Y value changed significantly by shifting superiorly, accompanied by an increase in DH. There was a loss of lordosis at the level of surgery, with the PRESTIGE LP endplates having an almost parallel endplate configuration. PMID

  18. Relationship between Spinal Cord Volume and Spinal Cord Injury due to Spinal Shortening

    PubMed Central

    Qiu, Feng; Yang, Jin-Cheng; Ma, Xiang-Yang; Xu, Jun-Jie; Yang, Qing-Lei; Zhou, Xin; Xiao, Yao-Sheng; Hu, Hai-Sheng; Xia, Li-Hui

    2015-01-01

    Vertebral column resection is associated with a risk of spinal cord injury. In the present study, using a goat model, we aimed to investigate the relationship between changes in spinal cord volume and spinal cord injury due to spinal shortening, and to quantify the spinal cord volume per 1-mm height in order to clarify a safe limit for shortening. Vertebral column resection was performed at T10 in 10 goats. The spinal cord was shortened until the somatosensory-evoked potential was decreased by 50% from the baseline amplitude or delayed by 10% relative to the baseline peak latency. A wake-up test was performed, and the goats were observed for two days postoperatively. Magnetic resonance imaging was used to measure the spinal cord volume, T10 height, disc height, osteotomy segment height, and spinal segment height pre- and postoperatively. Two of the 10 goats were excluded, and hence, only data from eight goats were analyzed. The somatosensory-evoked potential of these eight goats demonstrated meaningful changes. With regard to neurologic function, five and three goats were classified as Tarlov grades 5 and 4 at two days postoperatively. The mean shortening distance was 23.6 ± 1.51 mm, which correlated with the d-value (post-pre) of the spinal cord volume per 1-mm height of the osteotomy segment (r = 0.95, p < 0.001) and with the height of the T10 body (r = 0.79, p = 0.02). The mean d-value (post-pre) of the spinal cord volume per 1-mm height of the osteotomy segment was 142.87 ± 0.59 mm3 (range, 142.19–143.67 mm3). The limit for shortening was approximately 106% of the vertebral height. The mean volumes of the osteotomy and spinal segments did not significantly change after surgery (t = 0.310, p = 0.765 and t = 1.241, p = 0.255, respectively). Thus, our results indicate that the safe limit for shortening can be calculated using the change in spinal cord volume per 1-mm height. PMID:26001196

  19. Remote spinal epidural haematoma after spinal anaesthesia presenting with a ‘spinal lucid interval’

    PubMed Central

    Madhugiri, Venkatesh S; Singh, Manish; Sasidharan, Gopalakrishnan M; Kumar, V R Roopesh

    2012-01-01

    An obstetric patient who had no significant risk factors developed a spinal epidural haematoma remote from the site of needle puncture (for administration of spinal anaesthesia). The clinical deficits were manifest after recovery from the motor blockade had started a phenomenon that we have termed as a ‘spinal lucid interval’. The patient developed flaccid paraplegia with a sharp sensory level and urinary retention. The patient underwent emergency laminectomy and evacuation of the haematoma. She gradually recovered near normal power and was ambulant independently and had normal sphincter function at follow-up. PMID:23109417

  20. Overview of Spinal Cord Disorders

    MedlinePlus

    ... temperature from the body to the spinal cord. Did You Know... Doctors can often tell where the ... on symptoms and results of a physical examination. Did You Know... Nerves from the lowest parts of ...

  1. Risks associated with spinal manipulation.

    PubMed

    Stevinson, Clare; Ernst, Edzard

    2002-05-01

    The aim of this systematic review was to summarize the evidence about the risks of spinal manipulation. Articles were located through searching three electronic databases (MEDLINE, EMBASE, Cochrane Library), contacting experts (n =9), scanning reference lists of relevant articles, and searching departmental files. Reports in any language containing data relating to risks associated with spinal manipulation were included, irrespective of the profession of the therapist. Where available, systematic reviews were used as the basis of this article. All papers were evaluated independently by the authors. Data from prospective studies suggest that minor, transient adverse events occur in approximately half of all patients receiving spinal manipulation. The most common serious adverse events are vertebrobasilar accidents, disk herniation, and cauda equina syndrome. Estimates of the incidence of serious complications range from 1 per 2 million manipulations to 1 per 400,000. Given the popularity of spinal manipulation, its safety requires rigorous investigation. PMID:12015249

  2. What Is Spinal Cord Injury?

    MedlinePlus

    ... lowest point on the spinal cord below which sensory feeling and motor movement diminish or disappear. The ... injury is so severe that almost all feeling (sensory function) and all ability to control movement (motor ...

  3. Three-dimensional kinematics of the equine spine during canter.

    PubMed

    Faber, M; Johnston, C; Schamhardt, H C; van Weeren, P R; Roepstorff, L; Barneveld, A

    2001-04-01

    Most research on equine kinematics has previously been performed in the walking and/or trotting animal. This is also true for the few studies on the kinematics of the equine back. These studies have, for the major part, focused on the flexion-extension movement in the sagittal plane. However, vertebrae can rotate in 3 dimensions. This study was designed to determine all 3 rotations in various segments of the vertebral column of a cantering horse. Five Dutch Warmblood horses were measured during treadmill canter (7.3 m/s). Steinmann pins were inserted into the dorsal spinous processes of 8 thoracic (T), lumbar (L) and sacral (S) vertebrae and into both tubera coxae. A set of 4 markers was rigidly attached to each pin. The marker data were used to calculate a rotation matrix that was subsequently decomposed into 3 orthogonal rotations (flexion/extension [FE]; lateral bending [LB] and axial rotation [AR]). For the 3 rotations the variability between the horses was low for FE, slightly larger for AR and largest for LB. The maximal range of motion (mean +/- s.d.) for FE, LB and AR was 15.8 +/- 1.3 degrees, 5.2 +/- 0.7 degrees and 7.8 +/- 1.2 degrees, respectively. With respect to relative angles, the largest FE motion was found between L5 and S3 with values for the range of motion up to 8.6 degrees. Simultaneous rotation of successive vertebrae was observed particularly during the single support and suspension phases in the stride cycle, which increases spinal stability. For all rotations, a close correlation was observed between the timing of the vertebral rotations and the pro- and retraction of the limbs. PMID:11721556

  4. Leuprolide acetate induces structural and functional recovery of injured spinal cord in rats.

    PubMed

    Díaz Galindo, Carmen; Gómez-González, Beatriz; Salinas, Eva; Calderón-Vallejo, Denisse; Hernández-Jasso, Irma; Bautista, Eduardo; Quintanar, J Luis

    2015-11-01

    Gonadotropin-releasing hormone (GnRH) and its synthetic analog leuprolide acetate, a GnRH agonist, have neurotrophic properties. This study was designed to determine whether administration of leuprolide acetate can improve locomotor behavior, gait, micturition reflex, spinal cord morphology and the amount of microglia in the lesion epicenter after spinal cord injury in rats. Rats with spinal cord compression injury were administered leuprolide acetate or saline solution for 5 weeks. At the 5(th) week, leuprolide acetate-treated rats showed locomotor activity recovery by 38%, had improvement in kinematic gait and exhibited voiding reflex recovery by 60%, as compared with the 1(st) week. By contrast, saline solution-treated rats showed locomotor activity recovery only by 7%, but voiding reflex did not recover. More importantly, leuprolide acetate treatment reduced microglial immunological reaction and induced a trend towards greater area of white and gray matter in the spinal cord. Therefore, leuprolide acetate has great potential to repair spinal cord injury. PMID:26807118

  5. Leuprolide acetate induces structural and functional recovery of injured spinal cord in rats

    PubMed Central

    Díaz Galindo, Carmen; Gómez-González, Beatriz; Salinas, Eva; Calderón-Vallejo, Denisse; Hernández-Jasso, Irma; Bautista, Eduardo; Quintanar, J Luis

    2015-01-01

    Gonadotropin-releasing hormone (GnRH) and its synthetic analog leuprolide acetate, a GnRH agonist, have neurotrophic properties. This study was designed to determine whether administration of leuprolide acetate can improve locomotor behavior, gait, micturition reflex, spinal cord morphology and the amount of microglia in the lesion epicenter after spinal cord injury in rats. Rats with spinal cord compression injury were administered leuprolide acetate or saline solution for 5 weeks. At the 5th week, leuprolide acetate-treated rats showed locomotor activity recovery by 38%, had improvement in kinematic gait and exhibited voiding reflex recovery by 60%, as compared with the 1st week. By contrast, saline solution-treated rats showed locomotor activity recovery only by 7%, but voiding reflex did not recover. More importantly, leuprolide acetate treatment reduced microglial immunological reaction and induced a trend towards greater area of white and gray matter in the spinal cord. Therefore, leuprolide acetate has great potential to repair spinal cord injury. PMID:26807118

  6. Short term modulation of trunk neuromuscular responses following spinal manipulation: a control group study

    PubMed Central

    2013-01-01

    Background Low back pain (LBP) is one of the most frequent musculoskeletal conditions in industrialized countries and its economic impact is important. Spinal manipulation therapy (SMT) is believed to be a valid approach in the treatment of both acute and chronic LBP. It has also been shown that SMT can modulate the electromyographic (EMG) activity of the paraspinal muscle. The purpose of this study was to investigate, in a group of patients with low back pain, the persistence of changes observed in trunk neuromuscular responses after a spinal manipulation (SMT). Methods Sixty adult participants with LBP performed a block of 5 flexion-extension movements. Participants in the experimental group (n=30) received lumbar SMT whereas participants in the control group (n=30) were positioned similarly for the treatment but did not receive SMT. Blocks of flexion-extension movements were repeated immediately after the manipulation as well as 5 and 30 minutes after SMT (or control position). EMG activity of paraspinal muscles was recorded at L2 and L5 level and kinematic data were collected to evaluate the lumbo-pelvic kinematics. Pain intensity was noted after each block. Normalized EMG, pain intensity and lumbo-pelvic kinematics were compared across experimental conditions. Results Participants from the control group showed a significant increase in EMG activity during the last block (30 min) of flexion-extension trials in both flexion and full-flexion phases at L2. Increase in VAS scores was also observed in the last 2 blocks (5 min and 30 min) in the control group. No significant group x time interaction was seen at L5. No significant difference was observed in the lumbo-pelvic kinematics. Conclusion Changes in trunk neuromuscular control following HVLA spinal manipulation may reduce sensitization or muscle fatigue effects related to repetitive movement. Future studies should investigate short term changes in neuromuscular components, tissue properties and clinical

  7. Neurotrophins and spinal circuit function

    PubMed Central

    Boyce, Vanessa S.; Mendell, Lorne M.

    2014-01-01

    Work early in the last century emphasized the stereotyped activity of spinal circuits based on studies of reflexes. However, the last several decades have focused on the plasticity of these spinal circuits. These considerations began with studies of the effects of monoamines on descending and reflex circuits. In recent years new classes of compounds called growth factors that are found in peripheral nerves and the spinal cord have been shown to affect circuit behavior in the spinal cord. In this review we will focus on the effects of neurotrophins, particularly nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), on spinal circuits. We also discuss evidence that these molecules can modify functions including nociceptive behavior, motor reflexes and stepping behavior. Since these substances and their receptors are normally present in the spinal cord, they could potentially be useful in improving function in disease states and after injury. Here we review recent findings relevant to these translational issues. PMID:24926235

  8. [Subarachnoid hematoma and spinal anesthesia].

    PubMed

    Dupeyrat, A; Dequiré, P M; Mérouani, A; Moullier, P; Eid, G

    1990-01-01

    Two cases of spinal subarachnoid haematoma occurring after spinal anaesthesia are reported. In the first case, lumbar puncture was attempted three times in a 81-year-old man; spinal anaesthesia trial was than abandoned, and the patient given a general anaesthetic. He was given prophylactic calcium heparinate soon after surgery. On the fourth day, the patient became paraparetic. Radioculography revealed a blockage between T10 and L3. Laminectomy was performed to remove the haematoma, but the patient recovered motor activity only very partially. The second case was a 67-year-old man, in whom spinal anaesthesia was easily carried out. He was also given prophylactic calcium heparinate soon after surgery. On the fourth postoperative day, pulmonary embolism was suspected. Heparin treatment was then started. Twelve hours later, lumbar and bilateral buttock pain occurred, which later spread to the neck. On the eighth day, the patient had neck stiffness and two seizures. Emergency laminectomy was carried out, which revealed a subarachnoid haematoma spreading to a level higher than T6 and below L1, with no flow of cerebrospinal fluid, and a non pulsatile spinal cord. Surgery was stopped. The patient died on the following day. Both these cases are similar to those previously reported and point out the role played by anticoagulants. Because early diagnosis of spinal cord compression is difficult, the prognosis is poor, especially in case of paraplegia. PMID:2278424

  9. Spinal muscular atrophy

    PubMed Central

    2011-01-01

    Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, resulting in progressive proximal muscle weakness and paralysis. Estimated incidence is 1 in 6,000 to 1 in 10,000 live births and carrier frequency of 1/40-1/60. This disease is characterized by generalized muscle weakness and atrophy predominating in proximal limb muscles, and phenotype is classified into four grades of severity (SMA I, SMAII, SMAIII, SMA IV) based on age of onset and motor function achieved. This disease is caused by homozygous mutations of the survival motor neuron 1 (SMN1) gene, and the diagnostic test demonstrates in most patients the homozygous deletion of the SMN1 gene, generally showing the absence of SMN1 exon 7. The test achieves up to 95% sensitivity and nearly 100% specificity. Differential diagnosis should be considered with other neuromuscular disorders which are not associated with increased CK manifesting as infantile hypotonia or as limb girdle weakness starting later in life. Considering the high carrier frequency, carrier testing is requested by siblings of patients or of parents of SMA children and are aimed at gaining information that may help with reproductive planning. Individuals at risk should be tested first and, in case of testing positive, the partner should be then analyzed. It is recommended that in case of a request on carrier testing on siblings of an affected SMA infant, a detailed neurological examination should be done and consideration given doing the direct test to exclude SMA. Prenatal diagnosis should be offered to couples who have previously had a child affected with SMA (recurrence risk 25%). The role of follow-up coordination has to be managed by an expert in neuromuscular disorders and in SMA who is able to plan a multidisciplinary intervention that includes pulmonary, gastroenterology/nutrition, and orthopedic care. Prognosis depends on the phenotypic

  10. Milky Way halo gas kinematics

    NASA Technical Reports Server (NTRS)

    Danly, L.

    1986-01-01

    Measurements of high resolution, short wavelength absorption data taken by IUE toward high latitude O and B stars are presented in a discussion of the large scale kinematic properties of Milky Way Halo gas. An analysis of these data demonstrates that: (1) the obsrved absorption widths (FWHM) of Si II are very large, ranging up to 150 Km/s for the most distant halo star; this is much larger than is generally appreciated from optical data; (2) the absorption is observed to be systematically negative in radial velocity, indicating that cool material is, on the whole, flowing toward the disk of the galaxy; (3) there is some evidence for asymmetry between the northern and southern galactic hemispheres, in accordance with the HI 21 cm data toward the galactic poles; (4) low column density gas with highly negative radial LSR velocity (V less than -70 km/s) can be found toward stars beyond 1-3 kpc in the northern galactic hemisphere in all four quadrants of galactic longitude; and (5) only the profiles toward stars in the direction of known high velocity HI features show a clear two component structure.

  11. Kinematic modeling of scanner trajectories

    NASA Astrophysics Data System (ADS)

    Shevlin, Fergal P.

    1994-12-01

    Satellites are free-moving rigid bodies subject to various external forces which make them deviate from their predetermined positional and rotational trajectories. Since many remote sensing imaging devices use the linear pushbroom scanning model, trajectory deviation during the image scanning period causes geometric distortion in the imagery. Unless actual satellite trajectory during imaging is modeled, accurate rectification of imagery is impossible. A means of recovering the trajectory from known satellite motion is presented here. Rotational motion is usually sensed by gyroscopes which measure angular velocity. Translational motion can be determined in several ways including telemetry analysis and linear accelerometers. In more recent satellites GPS receivers may be used to determine motion data. We show how to interpolate and subsequently integrate angular velocity to yield a rotational trajectory. The screw, implemented as a dual-number quaternion, is shown to be a suitable parameterization of motion to model the trajectory as a kinematic chain. This representation is useful for image geometry analysis and hence for correction of image distortion. Applications of this parameterization to scanned image resampling and rectification are mentioned.

  12. Edge-driven microplate kinematics

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  13. Spinal Extradural Arachnoid Cyst

    PubMed Central

    Choi, Seung Won; Seong, Han Yu

    2013-01-01

    Spinal extradural arachnoid cyst (SEAC) is a rare disease and uncommon cause of compressive myelopathy. The etiology remains still unclear. We experienced 2 cases of SEACs and reviewed the cases and previous literatures. A 59-year-old man complained of both leg radiating pain and paresthesia for 4 years. His MRI showed an extradural cyst from T12 to L3 and we performed cyst fenestration and repaired the dural defect with tailored laminectomy. Another 51-year-old female patient visited our clinical with left buttock pain and paresthesia for 3 years. A large extradural cyst was found at T1-L2 level on MRI and a communication between the cyst and subarachnoid space was illustrated by CT-myelography. We performed cyst fenestration with primary repair of dural defect. Both patients' symptoms gradually subsided and follow up images taken 1-2 months postoperatively showed nearly disappeared cysts. There has been no documented recurrence in these two cases so far. Tailored laminotomy with cyst fenestration can be a safe and effective alternative choice in treating SEACs compared to traditional complete resection of cyst wall with multi-level laminectomy. PMID:24294463

  14. Automated quantification of lumbar vertebral kinematics from dynamic fluoroscopic sequences

    NASA Astrophysics Data System (ADS)

    Camp, Jon; Zhao, Kristin; Morel, Etienne; White, Dan; Magnuson, Dixon; Gay, Ralph; An, Kai-Nan; Robb, Richard

    2009-02-01

    We hypothesize that the vertebra-to-vertebra patterns of spinal flexion and extension motion of persons with lower back pain will differ from those of persons who are pain-free. Thus, it is our goal to measure the motion of individual lumbar vertebrae noninvasively from dynamic fluoroscopic sequences. Two-dimensional normalized mutual information-based image registration was used to track frame-to-frame motion. Software was developed that required the operator to identify each vertebra on the first frame of the sequence using a four-point "caliper" placed at the posterior and anterior edges of the inferior and superior end plates of the target vertebrae. The program then resolved the individual motions of each vertebra independently throughout the entire sequence. To validate the technique, 6 cadaveric lumbar spine specimens were potted in polymethylmethacrylate and instrumented with optoelectric sensors. The specimens were then placed in a custom dynamic spine simulator and moved through flexion-extension cycles while kinematic data and fluoroscopic sequences were simultaneously acquired. We found strong correlation between the absolute flexionextension range of motion of each vertebra as recorded by the optoelectric system and as determined from the fluoroscopic sequence via registration. We conclude that this method is a viable way of noninvasively assessing twodimensional vertebral motion.

  15. Saybolt universal viscosity converted to kinematic

    SciTech Connect

    Anaya, C.; Bermudez, O.

    1987-09-21

    This article describes a program for personal and handheld computers, written in Basic, which has been developed for the conversion of Saybolt universal viscosity in Saybolt Universal Seconds (SSU or SUS) to kinematic viscosity in centistokes (cSt), at any selected temperature. It was developed using the mathematical relationship presented in the American Society for Testing and Materials (ASTM) standard D2161-82. In the standard, an equation is presented to convert kinematic viscosity to Saybolt universal viscosity, but nothing is presented to convert from Saybolt to kinematic because it is necessary to find the roots of a nonexplicit function. There are several numerical methods that can be used to determine the roots of the nonexplicit function, and therefore, convert Saybolt universal viscosity to kinematic viscosity. In the program, the first iteration of the second-order Newton-Raphson method is followed by the Wegstein method as a convergence accelerator.

  16. Genetics Home Reference: spinal muscular atrophy

    MedlinePlus

    ... a loss of specialized nerve cells, called motor neurons , in the spinal cord and the part of ... spinal cord ( the brainstem ). The loss of motor neurons leads to weakness and wasting ( atrophy ) of muscles ...

  17. Spinal Cord Injury Model System Information Network

    MedlinePlus

    ... Go New to Website Managing Bowel Function After Spinal Cord Injury Resilience, Depression and Bouncing Back after SCI Getting ... the UAB-SCIMS Contact the UAB-SCIMS UAB Spinal Cord Injury Model System Newly Injured Health Daily Living Consumer ...

  18. Modal kinematics for multisection continuum arms.

    PubMed

    Godage, Isuru S; Medrano-Cerda, Gustavo A; Branson, David T; Guglielmino, Emanuele; Caldwell, Darwin G

    2015-06-01

    This paper presents a novel spatial kinematic model for multisection continuum arms based on mode shape functions (MSF). Modal methods have been used in many disciplines from finite element methods to structural analysis to approximate complex and nonlinear parametric variations with simple mathematical functions. Given certain constraints and required accuracy, this helps to simplify complex phenomena with numerically efficient implementations leading to fast computations. A successful application of the modal approximation techniques to develop a new modal kinematic model for general variable length multisection continuum arms is discussed. The proposed method solves the limitations associated with previous models and introduces a new approach for readily deriving exact, singularity-free and unique MSF's that simplifies the approach and avoids mode switching. The model is able to simulate spatial bending as well as straight arm motions (i.e., pure elongation/contraction), and introduces inverse position and orientation kinematics for multisection continuum arms. A kinematic decoupling feature, splitting position and orientation inverse kinematics is introduced. This type of decoupling has not been presented for these types of robotic arms before. The model also carefully accounts for physical constraints in the joint space to provide enhanced insight into practical mechanics and impose actuator mechanical limitations onto the kinematics thus generating fully realizable results. The proposed method is easily applicable to a broad spectrum of continuum arm designs. PMID:25969947

  19. Iterative inverse kinematics with manipulator configuration control

    SciTech Connect

    Grudic, G.Z.; Lawrence, P.D.

    1993-08-01

    A new method, termed the offset modification method (OM method), for solving the manipulator inverse kinematics problem is presented. The OM method works by modifying the link offset values of a manipulator until it is possible to derive closed-form inverse kinematics equations for the resulting manipulator (termed the model manipulator). This procedure allows one to derive a set of three nonlinear equations in three unknowns that, when numerically solved, give an inverse kinematics solution for the original manipulator. The OM method can be applied to manipulators with any number of degrees of freedom, as long as the manipulator satisfies a given set of conditions (Theorem 1). The OM method is tested on a 6-degree-of-freedom manipulator that has no known closed-form inverse kinematics equations. It is shown that the OM method is applicable to real-time manipulator control, can be used to guarantee convergence to a desired endpoint position and orientation (if it exists), and allows one to directly choose which inverse kinematics solution the algorithm will converge to (as specified in the model manipulator closed-form inverse kinematics equations). Applications of the method to other 6-DOF manipulator geometries and to redundant manipulators (i.e. greater than 6 DOF geometries) are discussed.

  20. Inverse Kinematics for Upper Limb Compound Movement Estimation in Exoskeleton-Assisted Rehabilitation.

    PubMed

    Cortés, Camilo; de Los Reyes-Guzmán, Ana; Scorza, Davide; Bertelsen, Álvaro; Carrasco, Eduardo; Gil-Agudo, Ángel; Ruiz-Salguero, Oscar; Flórez, Julián

    2016-01-01

    Robot-Assisted Rehabilitation (RAR) is relevant for treating patients affected by nervous system injuries (e.g., stroke and spinal cord injury). The accurate estimation of the joint angles of the patient limbs in RAR is critical to assess the patient improvement. The economical prevalent method to estimate the patient posture in Exoskeleton-based RAR is to approximate the limb joint angles with the ones of the Exoskeleton. This approximation is rough since their kinematic structures differ. Motion capture systems (MOCAPs) can improve the estimations, at the expenses of a considerable overload of the therapy setup. Alternatively, the Extended Inverse Kinematics Posture Estimation (EIKPE) computational method models the limb and Exoskeleton as differing parallel kinematic chains. EIKPE has been tested with single DOF movements of the wrist and elbow joints. This paper presents the assessment of EIKPE with elbow-shoulder compound movements (i.e., object prehension). Ground-truth for estimation assessment is obtained from an optical MOCAP (not intended for the treatment stage). The assessment shows EIKPE rendering a good numerical approximation of the actual posture during the compound movement execution, especially for the shoulder joint angles. This work opens the horizon for clinical studies with patient groups, Exoskeleton models, and movements types. PMID:27403420

  1. Inverse Kinematics for Upper Limb Compound Movement Estimation in Exoskeleton-Assisted Rehabilitation

    PubMed Central

    Cortés, Camilo; de los Reyes-Guzmán, Ana; Scorza, Davide; Bertelsen, Álvaro; Carrasco, Eduardo; Gil-Agudo, Ángel; Ruiz-Salguero, Oscar; Flórez, Julián

    2016-01-01

    Robot-Assisted Rehabilitation (RAR) is relevant for treating patients affected by nervous system injuries (e.g., stroke and spinal cord injury). The accurate estimation of the joint angles of the patient limbs in RAR is critical to assess the patient improvement. The economical prevalent method to estimate the patient posture in Exoskeleton-based RAR is to approximate the limb joint angles with the ones of the Exoskeleton. This approximation is rough since their kinematic structures differ. Motion capture systems (MOCAPs) can improve the estimations, at the expenses of a considerable overload of the therapy setup. Alternatively, the Extended Inverse Kinematics Posture Estimation (EIKPE) computational method models the limb and Exoskeleton as differing parallel kinematic chains. EIKPE has been tested with single DOF movements of the wrist and elbow joints. This paper presents the assessment of EIKPE with elbow-shoulder compound movements (i.e., object prehension). Ground-truth for estimation assessment is obtained from an optical MOCAP (not intended for the treatment stage). The assessment shows EIKPE rendering a good numerical approximation of the actual posture during the compound movement execution, especially for the shoulder joint angles. This work opens the horizon for clinical studies with patient groups, Exoskeleton models, and movements types. PMID:27403420

  2. Isolated intramedullary spinal cord cysticercosis

    PubMed Central

    Agale, Shubhangi V.; Bhavsar, Shweta; Choudhury, Barnik; Manohar, Vidhya

    2012-01-01

    We report a case of intradural, intramedullary, spinal cord neurocysticercosis at dorsal 10-11 (D10-11) level in a mentally retarded male. A 38-year-old, mentally retarded male presented with weakness and stiffness in both the lower limbs and waist since one year. Magnetic resonance imaging revealed a D10-D11 intradural space occupying lesion with cord compression. Intraoperatively, the tumor was grayish white, soft, cystic, and intramedullary with a well-defined plane with surrounding cord tissue. Gross examination revealed a cystic lesion of 1.5×1×0.8 cm, with a whitish nodule of 0.3 cm in diameter. The cyst wall was thin, shiny, and translucent. Microscopic examination revealed cysticercous cyst. Spinal neurocysticercosis should be considered in differential diagnosis of spinal mass lesion in patients residing in endemic area such as India. PMID:22870160

  3. Learning from the spinal cord

    PubMed Central

    Loeb, Gerald E

    2001-01-01

    The graceful control of multiarticulated limbs equipped with slow, non-linear actuators (muscles) is a difficult problem for which robotic engineering affords no general solution. The vertebrate spinal cord provides an existence proof that such control is, indeed, possible. The biological solution is complex and incompletely known, despite a century of meticulous neurophysiological research, celebrated in part by this symposium. This is frustrating for those who would reanimate paralysed limbs either through promoting regeneration of the injured spinal cord or by functional electrical stimulation. The importance of and general role played by the spinal cord might be more easily recognized by analogy to marionette puppets, another system in which a brain (the puppeteer's) must cope with a large number of partially redundant actuators (strings) moving a mechanical linkage with complex intrinsic properties. PMID:11351019

  4. Evaluation of spinal cord injury animal models

    PubMed Central

    Zhang, Ning; Fang, Marong; Chen, Haohao; Gou, Fangming; Ding, Mingxing

    2014-01-01

    Because there is no curative treatment for spinal cord injury, establishing an ideal animal model is important to identify injury mechanisms and develop therapies for individuals suffering from spinal cord injuries. In this article, we systematically review and analyze various kinds of animal models of spinal cord injury and assess their advantages and disadvantages for further studies. PMID:25598784

  5. Swimming as a Model of Task-Specific Locomotor Retraining After Spinal Cord Injury in the Rat

    PubMed Central

    Magnuson, David S. K.; Smith, Rebecca R.; Brown, Edward H.; Enzmann, Gaby; Angeli, Claudia; Quesada, Peter M.; Burke, Darlene

    2010-01-01

    Background The authors have shown that rats can be retrained to swim after a moderately severe thoracic spinal cord contusion. They also found that improvements in body position and hindlimb activity occurred rapidly over the first 2 weeks of training, reaching a plateau by week 4. Overground walking was not influenced by swim training, suggesting that swimming may be a task-specific model of locomotor retraining. Objective To provide a quantitative description of hindlimb movements of uninjured adult rats during swimming, and then after injury and retraining. Methods The authors used a novel and streamlined kinematic assessment of swimming in which each limb is described in 2 dimensions, as 3 segments and 2 angles. Results The kinematics of uninjured rats do not change over 4 weeks of daily swimming, suggesting that acclimatization does not involve refinements in hindlimb movement. After spinal cord injury, retraining involved increases in hindlimb excursion and improved limb position, but the velocity of the movements remained slow. Conclusion These data suggest that the activity pattern of swimming is hardwired in the rat spinal cord. After spinal cord injury, repetition is sufficient to bring about significant improvements in the pattern of hindlimb movement but does not improve the forces generated, leaving the animals with persistent deficits. These data support the concept that force (load) and pattern generation (recruitment) are independent and may have to be managed together with respect to postinjury rehabilitation. PMID:19270266

  6. Lumbar spinal loads and muscle activity during a golf swing.

    PubMed

    Lim, Young-Tae; Chow, John W; Chae, Woen-Sik

    2012-06-01

    This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads. PMID:22900401

  7. Recognising metastatic spinal cord compression.

    PubMed

    Bowers, Ben

    2015-04-01

    Metastatic spinal cord compression (MSCC) is a potentially life changing oncological emergency. Neurological function and quality of life can be preserved if patients receive an early diagnosis and rapid access to acute interventions to prevent or reduce nerve damage. Symptoms include developing spinal pain, numbness or weakness in arms or legs, or unexplained changes in bladder and bowel function. Community nurses are well placed to pick up on the 'red flag' symptoms of MSCC and ensure patients access prompt, timely investigations to minimise damage. PMID:25839873

  8. [Spinal column: implants and revisions].

    PubMed

    Krieg, S M; Meyer, H S; Meyer, B

    2016-03-01

    Non-fusion spinal implants are designed to reduce the commonly occurring risks and complications of spinal fusion surgery, e.g. long duration of surgery, high blood loss, screw loosening and adjacent segment disease, by dynamic or movement preserving approaches. This principle could be shown for interspinous spacers, cervical and lumbar total disc replacement and dynamic stabilization; however, due to the continuing high rate of revision surgery, the indications for surgery require as much attention and evidence as comparative data on the surgical technique itself. PMID:26779646

  9. Melatonin lowers edema after spinal cord injury

    PubMed Central

    Li, Cheng; Chen, Xiao; Qiao, Suchi; Liu, Xinwei; Liu, Chang; Zhu, Degang; Su, Jiacan; Wang, Zhiwei

    2014-01-01

    Melatonin has been shown to diminish edema in rats. Melatonin can be used to treat spinal cord injury. This study presumed that melatonin could relieve spinal cord edema and examined how it might act. Our experiments found that melatonin (100 mg/kg, i.p.) could reduce the water content of the spinal cord, and suppress the expression of aquaporin-4 and glial fibrillary acidic protein after spinal cord injury. This suggests that the mechanism by which melatonin alleviates the damage to the spinal cord by edema might be related to the expression of aquaporin-4 and glial fibrillary acidic protein. PMID:25657743

  10. Inverse kinematic-based robot control

    NASA Technical Reports Server (NTRS)

    Wolovich, W. A.; Flueckiger, K. F.

    1987-01-01

    A fundamental problem which must be resolved in virtually all non-trivial robotic operations is the well-known inverse kinematic question. More specifically, most of the tasks which robots are called upon to perform are specified in Cartesian (x,y,z) space, such as simple tracking along one or more straight line paths or following a specified surfacer with compliant force sensors and/or visual feedback. In all cases, control is actually implemented through coordinated motion of the various links which comprise the manipulator; i.e., in link space. As a consequence, the control computer of every sophisticated anthropomorphic robot must contain provisions for solving the inverse kinematic problem which, in the case of simple, non-redundant position control, involves the determination of the first three link angles, theta sub 1, theta sub 2, and theta sub 3, which produce a desired wrist origin position P sub xw, P sub yw, and P sub zw at the end of link 3 relative to some fixed base frame. Researchers outline a new inverse kinematic solution and demonstrate its potential via some recent computer simulations. They also compare it to current inverse kinematic methods and outline some of the remaining problems which will be addressed in order to render it fully operational. Also discussed are a number of practical consequences of this technique beyond its obvious use in solving the inverse kinematic question.

  11. Investigation of impact loading rate effects on the ligamentous cervical spinal load-partitioning using finite element model of functional spinal unit C2-C3.

    PubMed

    Mustafy, Tanvir; El-Rich, Marwan; Mesfar, Wissal; Moglo, Kodjo

    2014-09-22

    The cervical spine functions as a complex mechanism that responds to sudden loading in a unique manner, due to intricate structural features and kinematics. The spinal load-sharing under pure compression and sagittal flexion/extension at two different impact rates were compared using a bio-fidelic finite element (FE) model of the ligamentous cervical functional spinal unit (FSU) C2-C3. This model was developed using a comprehensive and realistic geometry of spinal components and material laws that include strain rate dependency, bone fracture, and ligament failure. The range of motion, contact pressure in facet joints, failure forces in ligaments were compared to experimental findings. The model demonstrated that resistance of spinal components to impact load is dependent on loading rate and direction. For the loads applied, stress increased with loading rate in all spinal components, and was concentrated in the outer intervertebral disc (IVD), regions of ligaments to bone attachment, and in the cancellous bone of the facet joints. The highest stress in ligaments was found in capsular ligament (CL) in all cases. Intradiscal pressure (IDP) in the nucleus was affected by loading rate change. It increased under compression/flexion but decreased under extension. Contact pressure in the facet joints showed less variation under compression, but increased significantly under flexion/extension particularly under extension. Cancellous bone of the facet joints region was the only component fractured and fracture occurred under extension at both rates. The cervical ligaments were the primary load-bearing component followed by the IVD, endplates and cancellous bone; however, the latter was the most vulnerable to extension as it fractured at low energy impact. PMID:25129167

  12. Vestibulo-spinal reflex mechanisms

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.

    1981-01-01

    The specific objectives of experiments designed to investigate postural reflex behavior during sustained weightlessness are discussed. The first is to investigate, during prolonged weightlessness with Hoffmann response (H-reflex) measurement procedures, vestibulo-spinal reflexes associated with vestibular (otolith) responses evoked during an applied linear acceleration. This objective includes not only an evaluation of otolith-induced changes in a major postural muscle but also an investigation with this technique of the adaptive process of the vestibular system and spinal reflex mechanisms to this unique environment. The second objective is to relate space motion sickness to the results of this investigation. Finally, a return to the vestibulo-spinal and postural reflexes to normal values following the flight will be examined. The flight experiment involves activation of nerve tissue (tibial N) with electrical shock and the recording of resulting muscle activity (soleus) with surface electrodes. Soleus/spinal H-reflex testing procedures will be used in conjuction with linear acceleration through the subject's X-axis.

  13. SPINAL CORD INJURY (SCI) DATABASE

    EPA Science Inventory

    The National Spinal Cord Injury Database has been in existence since 1973 and captures data from SCI cases in the United States. Since its inception, 24 federally funded Model SCI Care Systems have contributed data to the National SCI Database. Statistics are derived from this da...

  14. Biomechanics of Degenerative Spinal Disorders

    PubMed Central

    Iorio, Justin A.; Jakoi, Andre M.

    2016-01-01

    The spine has several important functions including load transmission, permission of limited motion, and protection of the spinal cord. The vertebrae form functional spinal units, which represent the smallest segment that has characteristics of the entire spinal column. Discs and paired facet joints within each functional unit form a three-joint complex between which loads are transmitted. Surrounding the spinal motion segment are ligaments, composed of elastin and collagen, and joint capsules which restrict motion to within normal limits. Ligaments have variable strengths and act via different lever arm lengths to contribute to spinal stability. As a consequence of the longer moment arm from the spinous process to the instantaneous axis of rotation, inherently weaker ligaments (interspinous and supraspinous) are able to provide resistance to excessive flexion. Degenerative processes of the spine are a normal result of aging and occur on a spectrum. During the second decade of life, the intervertebral disc demonstrates histologic evidence of nucleus pulposus degradation caused by reduced end plate blood supply. As disc height decreases, the functional unit is capable of an increased range of axial rotation which subjects the posterior facet capsules to greater mechanical loads. A concurrent change in load transmission across the end plates and translation of the instantaneous axis of rotation further increase the degenerative processes at adjacent structures. The behavior of the functional unit is impacted by these processes and is reflected by changes in the stress-strain relationship. Back pain and other clinical symptoms may occur as a result of the biomechanical alterations of degeneration. PMID:27114783

  15. Biomechanics of Degenerative Spinal Disorders.

    PubMed

    Iorio, Justin A; Jakoi, Andre M; Singla, Anuj

    2016-04-01

    The spine has several important functions including load transmission, permission of limited motion, and protection of the spinal cord. The vertebrae form functional spinal units, which represent the smallest segment that has characteristics of the entire spinal column. Discs and paired facet joints within each functional unit form a three-joint complex between which loads are transmitted. Surrounding the spinal motion segment are ligaments, composed of elastin and collagen, and joint capsules which restrict motion to within normal limits. Ligaments have variable strengths and act via different lever arm lengths to contribute to spinal stability. As a consequence of the longer moment arm from the spinous process to the instantaneous axis of rotation, inherently weaker ligaments (interspinous and supraspinous) are able to provide resistance to excessive flexion. Degenerative processes of the spine are a normal result of aging and occur on a spectrum. During the second decade of life, the intervertebral disc demonstrates histologic evidence of nucleus pulposus degradation caused by reduced end plate blood supply. As disc height decreases, the functional unit is capable of an increased range of axial rotation which subjects the posterior facet capsules to greater mechanical loads. A concurrent change in load transmission across the end plates and translation of the instantaneous axis of rotation further increase the degenerative processes at adjacent structures. The behavior of the functional unit is impacted by these processes and is reflected by changes in the stress-strain relationship. Back pain and other clinical symptoms may occur as a result of the biomechanical alterations of degeneration. PMID:27114783

  16. Management of lumbar spinal stenosis.

    PubMed

    Lurie, Jon; Tomkins-Lane, Christy

    2016-01-01

    Lumbar spinal stenosis (LSS) affects more than 200,000 adults in the United States, resulting in substantial pain and disability. It is the most common reason for spinal surgery in patients over 65 years. Lumbar spinal stenosis is a clinical syndrome of pain in the buttocks or lower extremities, with or without back pain. It is associated with reduced space available for the neural and vascular elements of the lumbar spine. The condition is often exacerbated by standing, walking, or lumbar extension and relieved by forward flexion, sitting, or recumbency. Clinical care and research into lumbar spinal stenosis is complicated by the heterogeneity of the condition, the lack of standard criteria for diagnosis and inclusion in studies, and high rates of anatomic stenosis on imaging studies in older people who are completely asymptomatic. The options for non-surgical management include drugs, physiotherapy, spinal injections, lifestyle modification, and multidisciplinary rehabilitation. However, few high quality randomized trials have looked at conservative management. A systematic review concluded that there is insufficient evidence to recommend any specific type of non-surgical treatment. Several different surgical procedures are used to treat patients who do not improve with non-operative therapies. Given that rapid deterioration is rare and that symptoms often wax and wane or gradually improve, surgery is almost always elective and considered only if sufficiently bothersome symptoms persist despite trials of less invasive interventions. Outcomes (leg pain and disability) seem to be better for surgery than for non-operative treatment, but the evidence is heterogeneous and often of limited quality. PMID:26727925

  17. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    NASA Technical Reports Server (NTRS)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  18. Computer Assisted Mechanical Axis and Kinematic TKA

    PubMed Central

    McEwen, Peter; Mahoharan, Varaguna

    2016-01-01

    Introduction: Total knee arthroplasty (TKA) has traditionally been and largely continues to be aligned mechanically, that being with a neutral coronal plane mechanical tibiofemoral axis and a joint line orientated at 900 to this axis. Femoral component rotation is set by gap balancing or by externally rotating 30 from any of a number femoral reference lines. This produces a rectangular flexion gap and relaxes patellar tracking. Kinematic alignment (KA) is an alternative technique that aims to restore premorbid alignment, joint orientation and ligament tension. The basic premise for this technique is based on evidence that the medial and lateral femoral condyles consistently equate to cylinders of equal or near equal size and that therefore with a fixed radius, cruciate retaining implant, matched distal femoral, posterior femoral and proximal tibial resections, accounting for bone and cartilage already lost will reproduce the premorbid joint line and restore native premorbid kinematics. Femoral rotation is therefore referenced off the prearthritic posterior condylar axis (PCA) that is on average internally rotated to the AP axis. Kinematic alignment therefore has the potential to challenge patellar tracking, increase patellar load and potentially increase patellar complications. Method: Case control study – level of evidence III-2. Between November 2012 and June 2013 the senior author completed 104 consecutive computer assisted (CAS) kinematically aligned total knee arthroplasties (TKA) with a cruciate retaining, fixed bearing, single radius implant. The results of these surgeries were compared with the results of 91 consecutive CAS mechanically aligned TKA done between November 2011 and October 2012 using the same navigation system and implant Implant sizing and positioning as well as gap measurement and ligament balance was done with computer assistance in all cases. Data was collected prospectively and analysed retrospectively. Results: The Oxford Knee Score

  19. Highly damped kinematic coupling for precision instruments

    DOEpatents

    Hale, Layton C.; Jensen, Steven A.

    2001-01-01

    A highly damped kinematic coupling for precision instruments. The kinematic coupling provides support while causing essentially no influence to its nature shape, with such influences coming, for example, from manufacturing tolerances, temperature changes, or ground motion. The coupling uses three ball-cone constraints, each combined with a released flexural degree of freedom. This arrangement enables a gain of higher load capacity and stiffness, but can also significantly reduce the friction level in proportion to the ball radius divided by the distance between the ball and the hinge axis. The blade flexures reduces somewhat the stiffness of the coupling and provides an ideal location to apply constrained-layer damping which is accomplished by attaching a viscoelastic layer and a constraining layer on opposite sides of each of the blade flexures. The three identical ball-cone flexures provide a damped coupling mechanism to kinematically support the projection optics system of the extreme ultraviolet lithography (EUVL) system, or other load-sensitive apparatus.

  20. Kinematic hardening of a porous limestone

    NASA Astrophysics Data System (ADS)

    Cheatham, J. B.; Allen, M. B.; Celle, C. C.

    1984-10-01

    A concept for a kinematic hardening yield surface in stress space for Cordova Cream limestone (Austin Chalk) developed by Celle and Cheatham (1981) has been improved using Ziegler's modification of Prager's hardening rule (Ziegler, 1959). Data to date agree with the formulated concepts. It is shown how kinematic hardening can be used to approximate the yield surface for a wide range of stress states past the initial yield surface. The particular difficulty of identifying the yield surface under conditions of unloading or extension is noted. A yield condition and hardening rule which account for the strain induced anisotropy in Cordova Cream Limestone were developed. Although the actual yield surface appears to involve some change of size and shape, it is concluded that true kinematic hardening provides a basis for engineering calculations.

  1. Parametric characterization of spinal motions in osteoporotic vertebral fracture at level T12 with fluoroscopy.

    PubMed

    Lam, Shing Chun Benny; Allen, Robert; Pearson, Gill; Cooper, Cyrus

    2009-04-01

    Vertebral fractures due to osteoporosis are a common skeletal disorder affecting the mobility of the patients, although little is known about the relationship between spinal kinematics and osteoporotic fracture. The purpose of this study was to characterize the motions of the thoracolumbar spine affected by osteoporotic vertebral fracture at level T12 and compare the results with those of non-fracture osteoporosis subjects. We examined the continuous segmental kinematics of the vertebrae, and describe the segmental motion of the spine when a fracture at T12 is present. Fluoroscopy sequences of the thoracolumbar spines during sagittal and lateral flexion were collected from 16 subjects with osteoporosis of their spine (6 with vertebral fractures at T12, 10 without a fracture). Vertebrae T10-L2 in each frame of the sequences were landmarked. Kinematic parameters were calculated based on the landmarks and motion graphs were constructed. Compared to the control subjects who did not have a fracture, fracture subjects had a more asymmetric lateral range of motion (RoM) and required a longer time to complete certain phases of the motion cycle which are parameterized as lateral flexion ratio and percentage of motion cycle, respectively. Prolonged deflection was more frequently found from the fracture group. Characterizing the motions of the fractured vertebra together with its neighboring vertebrae with these kinematic parameters is useful in quantifying the dysfunction and may be a valuable aid to tracking progress of treatment. PMID:18614385

  2. [Iatrogenic spinal epidermoid tumors. A late complication of spinal puncture].

    PubMed

    Reina, M A; López-García, A; Dittmann, M; de Andrés, J A; Blázquez, M G

    1996-04-01

    INTRODUCTION. Epidermoid tumors in the spinal canal are rare. Whether congenitally or iatrogenically caused, they form as the result of epidermal cells implanted within the spinal channel. Such implantation can occur during a variety of procedures and events such as bullet wounds, surgery, myelography or punctures for diagnosis, anesthesia or treatment. Although this complication is not discussed in books or journals on anesthesiology, we have found it mentioned in over 100 published cases reporting iatrogenically caused spinal epidermoid tumors. ETIOPATHOGENESIS. Iatrogenic epidermoid tumors of the spine derive from the implantation of epidermal tissue transported inside the spinal canal during lumbar punctures without guidance or with inadequate guidance. There is ample evidence that such tumors are iatrogenic. All cases occur in patients with a history of lumbar puncture. They are rarely associated with congenital anomalies. They are extramedullary. They tend to develop near sites of earlier lumbar puncture, usually near the conus medullaris and the cauda equina. Iatrogenic epidermoid tumors of the spine have been reproduced experimentally in two studies in which autologous skin fragments were implanted in the spinal canal. CLINICAL SIGNS. These tumors are well tolerated by patients for extended periods of time, ranging from 2 to 10 years. At the cauda equinus, tumors can grow slowly for long periods without signs of nerve compression. Symptoms are directly related to tumor size and site. All patients with tumors at the cauda equinus report severe pain radiating toward the roots of compressed nerves. Nuclear magnetic resonance makes it possible to detect the tumor without administration of intrathecal contrast. At present gadolinium-DTPA improves the image so that these tumors can be distinguished from other types. The prognosis for epidermoid tumors of the spine is good, as they are histologically benign. Treatment is always surgical. CONCLUSION. Although the

  3. Kinematics and Control of Robot Manipulators

    NASA Astrophysics Data System (ADS)

    Paden, Bradley Evan

    This dissertation focuses on the kinematics and control of robot manipulators. The contribution to kinematics is a fundamental theorem on the design of manipulators with six revolute joints. The theorem states, roughly speaking, that manipulators which have six revolute joints and are modeled after the human arm are optimal and essentially unique. In developing the mathematical framework to prove this theorem, we define precisely the notions of length of a manipulator, well-connected-workspace, and work-volume. We contribute to control a set of analysis techniques for the design of variable structure (sliding mode) controllers for manipulators. The organization of the dissertation is the following. After introductory remarks in chapter one, the group of proper rigid motions, G, is introduced in chapter two. The tangent bundle of G is introduced and it is shown that the velocity of a rigid body can be represented by an element in the Lie algebra of G (commonly called a twist). Further, rigid motions which are exponentials of twists are used to describe four commonly occurring subproblems in robot kinematics. In chapter three, the exponentials of twists are used to write the forward kinematic map of robot manipulators and the subproblems of chapter two are used to solve the Stanford manipulator and an elbow manipulator. Chapter four focuses on manipulator singularities. Twist coordinates are used to find critical points of the forward kinematic map. The contribution to kinematics is contained in chapter five where a mathematical framework for studying the relationship between the design of 6R manipulators and their performance is developed. Chapter seven contains the contribution to control. The work of A. F. Filippov on differential equations with discontinuous right-hand-side and the work of F. H. Clarke on generalized gradients are combined to obtain a calculus for analyzing nonsmooth gradient systems. The techniques developed are applied to design a simple

  4. Tibial rotation kinematics subsequent to knee arthroplasty

    PubMed Central

    Collins, Duane J.; Khatib, Yasser H.; Parker, David A.; Jenkin, Deanne E.; Molnar, Robert B.

    2015-01-01

    Background The use of computer assisted joint replacement has facilitated precise intraoperative measurement of knee kinematics. The changes in “screw home mechanism” (SHM) resulting from Total Knee Arthroplasty (TKA) with different prostheses and constraints has not yet been accurately described. Methods A pilot study was first completed. Intraoperative kinematic data was collected two groups of 15 patients receiving different prostheses. Results On average, patients lost 5.3° of ER (SD = 6.1°). There was no significant difference between the prostheses or different prosthetic constraints. Conclusions There significant loss of SHM after TKA. Further research is required to understand its impact on patient function. PMID:25829754

  5. Hexapod kinematics for secondary mirror aberration control .

    NASA Astrophysics Data System (ADS)

    Schipani, P.

    This work deals with active correction of the aberrations in a telescope by moving the secondary mirror. A special attention is dedicated to the case of a secondary mirror whose motions are controlled by a 6-6 Stewart Platform (generally called by astronomers simply "hexapod", even if this term is more general). The kinematics of the device is studied. The non trivial forward kinematics problem is solved by an iterative algorithm fitting the necessities of an active optics system and fast enough to be used in a closed loop feedback control.

  6. Controlling chaotic robots with kinematical redundancy.

    PubMed

    Li, Li; Liu, Zhaohui; Zhang, Dengcai; Zhang, H

    2006-03-01

    Robots with kinematical redundancy under the pseudoinverse control exhibit undesirable chaotic joint motion, which leads to erratic behaviors. In this study, we used the delayed feedback method to control chaotic motions of a planar 3R rigid and a planar 3R flexible redundant robot under the pseudoinverse control when the end-effector traces a closed-path repeatedly in the work space. It was demonstrated that chaotic motions of robots with kinematical redundancy can be turned into regular motion when the delayed feedback method was applied with some appropriate parameters. This study provides a new insight helpful to solve the repeatability problem of redundant manipulators. PMID:16599763

  7. Long-Term Effects of Segmental Lumbar Spinal Fusion on Adjacent Healthy Discs: A Finite Element Study

    PubMed Central

    Srinivas, Gunti Ranga; Deb, Anindya; Kurnool, Goutham

    2016-01-01

    Study Design Experimental study. Purpose The aim of the study was to develop a finite element (FE) model to study the long-term effects of various types of lumbar spinal interventions on the discs adjacent to the fused segment. Overview of Literature Earlier FE studies have been limited to one particular type of fusion and comparative quantification of the adjacent disc stresses for different types of surgical interventions has not been reported. Methods A computer aided engineering (CAE) based approach using implicit FE analysis assessed the stresses in the lumbar discs adjacent to the fused segment following anterior and posterior lumbar spine fusions at one, two and three levels (with and without instrumentation). Results It was found that instrumentation and length of fusion were the most significant factors in increasing adjacent level stresses in the lumbar discs. Conclusions In the present study, a calibrated FE model that examined spinal interventions under similar loading and boundary conditions was used to provide quantitative data which would be useful for clinicians to understand the probable long-term effect of their choice of surgical intervention. PMID:27114758

  8. Calibration of parallel kinematic devices using sequential determination of kinematic parameters

    SciTech Connect

    JOKIEL JR.,BERNHARD; BIEG,LOTHAR F.; ZIEGERT,JOHN C.

    2000-04-06

    In PKM Machines, the Cartesian position and orientation of the tool point carried on the platform is obtained from a kinematic model of the particular machine. Accurate positioning of these machines relies on the accurate knowledge of the parameters of the kinematic model unique to the particular machine. The parameters in the kinematic model include the spatial locations of the joint centers on the machine base and moving platform, the initial strut lengths, and the strut displacements. The strut displacements are readily obtained from sensors on the machine. However, the remaining kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. The size and complexity of these machines generally makes it difficult and somewhat undesirable to determine the remaining kinematic parameters by direct inspection such as in a coordinate measuring machine. In order for PKMs to be useful for precision positioning applications, techniques must be developed to quickly calibrate the machine by determining the kinematic parameters without disassembly of the machine. A number of authors have reported techniques for calibration of PKMs (Soons, Masory, Zhuang et. al., Ropponen). In two other papers, the authors have reported on work recently completed by the University of Florida and Sandia National Laboratories on calibration of PKMs, which describes a new technique to sequentially determine the kinematic parameters of an assembled parallel kinematic device. The technique described is intended to be used with a spatial coordinate measuring device such as a portable articulated CMM measuring arm (Romer, Faro, etc.), a Laser Ball Bar (LBB), or a laser tracker (SMX< API, etc.). The material to be presented is as follows: (1) methods to identify the kinematic parameters of 6--6 variant Stewart platform manipulators including joint center locations relative to the workable and spindle nose

  9. Therapeutic approaches for spinal cord injury

    PubMed Central

    Cristante, Alexandre Fogaça; de Barros Filho, Tarcísio Eloy Pessoa; Marcon, Raphael Martus; Letaif, Olavo Biraghi; da Rocha, Ivan Dias

    2012-01-01

    This study reviews the literature concerning possible therapeutic approaches for spinal cord injury. Spinal cord injury is a disabling and irreversible condition that has high economic and social costs. There are both primary and secondary mechanisms of damage to the spinal cord. The primary lesion is the mechanical injury itself. The secondary lesion results from one or more biochemical and cellular processes that are triggered by the primary lesion. The frustration of health professionals in treating a severe spinal cord injury was described in 1700 BC in an Egyptian surgical papyrus that was translated by Edwin Smith; the papyrus reported spinal fractures as a “disease that should not be treated.” Over the last two decades, several studies have been performed to obtain more effective treatments for spinal cord injury. Most of these studies approach a patient with acute spinal cord injury in one of four manners: corrective surgery or a physical, biological or pharmacological treatment method. Science is unraveling the mechanisms of cell protection and neuroregeneration, but clinically, we only provide supportive care for patients with spinal cord injuries. By combining these treatments, researchers attempt to enhance the functional recovery of patients with spinal cord injuries. Advances in the last decade have allowed us to encourage the development of experimental studies in the field of spinal cord regeneration. The combination of several therapeutic strategies should, at minimum, allow for partial functional recoveries for these patients, which could improve their quality of life. PMID:23070351

  10. Cervical facet joint kinematics during bilateral facet dislocation

    PubMed Central

    Panjabi, Manohar M.; Simpson, Andrew K.; Pearson, Adam M.; Tominaga, Yasuhiro; Yue, James J.

    2007-01-01

    Previous biomechanical models of cervical bilateral facet dislocation (BFD) are limited to quasi-static loading or manual ligament transection. The goal of the present study was to determine the facet joint kinematics during high-speed BFD. Dislocation was simulated using ten cervical functional spinal units with muscle force replication by frontal impact of the lower vertebra, tilted posteriorly by 42.5°. Average peak rotations and anterior sliding (displacement of upper articulating facet surface along the lower), separation and compression (displacement of upper facet away from and towards the lower), and lateral shear were determined at the anterior and posterior edges of the right and left facets and statistically compared (P < 0.05). First, peak facet separation occurred, and was significantly greater at the left posterior facet edge, as compared to the anterior edges. Next, peak flexion rotation and anterior facet sliding occurred, followed by peak facet compression. The highest average facet translation peaks were 22.0 mm for anterior sliding, 7.9 mm for separation, 9.9 mm for compression and 3.6 mm for lateral shear. The highest average rotation of 63° occurred in flexion, significantly greater than all other directions. These events occurred, on average, within 0.29 s following impact. During BFD, the main sagittal motions included facet separation, flexion rotation, anterior sliding, followed by compression, however, non-sagittal motions also existed. These motions indicated that unilateral dislocation may precede bilateral dislocation. PMID:17566792

  11. ANALYTIC MODELING OF THE MORETON WAVE KINEMATICS

    SciTech Connect

    Temmer, M.; Veronig, A. M.

    2009-09-10

    The issue whether Moreton waves are flare-ignited or coronal mass ejection (CME)-driven, or a combination of both, is still a matter of debate. We develop an analytical model describing the evolution of a large-amplitude coronal wave emitted by the expansion of a circular source surface in order to mimic the evolution of a Moreton wave. The model results are confronted with observations of a strong Moreton wave observed in association with the X3.8/3B flare/CME event from 2005 January 17. Using different input parameters for the expansion of the source region, either derived from the real CME observations (assuming that the upward moving CME drives the wave), or synthetically generated scenarios (expanding flare region, lateral expansion of the CME flanks), we calculate the kinematics of the associated Moreton wave signature. Those model input parameters are determined which fit the observed Moreton wave kinematics best. Using the measured kinematics of the upward moving CME as the model input, we are not able to reproduce the observed Moreton wave kinematics. The observations of the Moreton wave can be reproduced only by applying a strong and impulsive acceleration for the source region expansion acting in a piston mechanism scenario. Based on these results we propose that the expansion of the flaring region or the lateral expansion of the CME flanks is more likely the driver of the Moreton wave than the upward moving CME front.

  12. Constrained tri-sphere kinematic positioning system

    DOEpatents

    Viola, Robert J

    2010-12-14

    A scalable and adaptable, six-degree-of-freedom, kinematic positioning system is described. The system can position objects supported on top of, or suspended from, jacks comprising constrained joints. The system is compatible with extreme low temperature or high vacuum environments. When constant adjustment is not required a removable motor unit is available.

  13. Computer Software & Programing Utilization in Kinematics.

    ERIC Educational Resources Information Center

    Zahraee, Mohammad A.; And Others

    This paper discusses two software packages used in kinematics courses at Purdue University, Calumet (Indiana) and some algorithms written by students for cam design. The first software package, 4BAR, requires the user to define the particular four bar linkage in terms of lengths of the individual links and the angle and distance to the coupler…

  14. Kinematics of foldable discrete space cranes

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.

    1985-01-01

    Exact kinematic description of a NASA proposed prototype foldable-deployable discrete space crane are presented. A computer program is developed which maps the geometry of the crane once controlling parameters are specified. The program uses a building block type approach in which it calculates the local coordinates of each repeating cell and then combines them with respect to a global coordinates system.

  15. Compound nucleus studies withy reverse kinematics

    SciTech Connect

    Moretto, L.G.

    1985-06-01

    Reverse kinematics reactions are used to demonstrate the compound nucleus origin of intermediate mass particles at low energies and the extension of the same mechanism at higher energies. No evidence has appeared in our energy range for liquid-vapor equilibrium or cold fragmentation mechanisms. 11 refs., 12 figs.

  16. KINEMATICS OF STELLAR POPULATIONS IN POSTSTARBURST GALAXIES

    SciTech Connect

    Hiner, Kyle D.; Canalizo, Gabriela E-mail: khiner@astro-udec.cl

    2015-01-20

    Poststarburst galaxies host a population of early-type stars (A or F) but simultaneously lack indicators of ongoing star formation such as [O II] emission. Two distinct stellar populations have been identified in these systems: a young poststarburst population superimposed on an older host population. We present a study of nine poststarburst galaxies with the following objectives: (1) to investigate whether and how kinematical differences between the young and old populations of stars can be measured, and (2) to gain insight into the formation mechanism of the young population in these systems. We fit high signal-to-noise spectra with two independent populations in distinct spectral regions: the Balmer region, the Mg IB region, and the Ca triplet when available. We show that the kinematics of the two populations largely track one another if measured in the Balmer region with high signal-to-noise data. Results from examining the Faber-Jackson relation and the fundamental plane indicate that these objects are not kinematically disturbed relative to more evolved spheroids. A case study of the internal kinematics of one object in our sample shows it to be pressure supported and not rotationally dominated. Overall our results are consistent with merger-induced starburst scenarios where the young population is observed during the later stages of the merger.

  17. Internal kinematics of H II galaxies

    NASA Astrophysics Data System (ADS)

    Carvalho, M. S.; Plana, H.

    2014-10-01

    H II galaxies are dwarf galaxies characterized by high stellar formation rate with spectrum dominated by strong emission lines, superimposed on a weak stellar continuum. The study of internal kinematics of these objects may be realized using the observed emission lines. Based on these lines we obtained monochromatic intensity, velocity dispersion and radial velocity maps. We have studied the internal kinematics of two H II galaxies: UM 461 and CTS 1020, observed with the Gemini South telescope using the GMOS instrument equipped with an IFU. We aim to investigate the origin of the line-broadening observed on emission lines from the use of kinematics diagnostic diagrams: I vs σ, I vs V, eV vs σ. The analysis of these diagrams was based on the Cometary Stirring Model that allows us to identify, for example, the presence of expanding shells and stellar winds. We found that radial velocity and velocity dispersion maps, for each galaxy, show a different kinematical pattern, although both are H II galaxies. CTS 1020 shows a velocity gradient consistent with a rotating disc with a velocity amplitude of ˜ 40 km s^{-1}. On the other hand UM 461 does not exhibit a typical pattern of a rotating system, despite of the observed velocity gradient in both emission nuclei.

  18. Action Experience Changes Attention to Kinematic Cues

    PubMed Central

    Filippi, Courtney A.; Woodward, Amanda L.

    2016-01-01

    The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-months-old infants. To measure online anticipation of actions infants watched videos where the actor’s hand provided kinematic information (in its orientation) about the type of object that the actor was going to reach for. The actor’s hand orientation either matched the orientation of a rod (congruent cue) or did not match the orientation of the rod (incongruent cue). To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first) × 2 (congruent kinematic cue vs. incongruent kinematic cue) between-subjects design. We show that 13-months-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues—suggesting that short-term experience changes attention to kinematics. PMID:26913012

  19. KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION

    SciTech Connect

    Jones, Courtney; Dickey, John M.

    2012-07-01

    Using H I absorption spectra from the International Galactic Plane Survey, a new method is implemented to resolve the kinematic distance ambiguity for 75 H II regions with known systemic velocities from radio recombination lines. A further 40 kinematic distance determinations are made for H II region candidates without known systemic velocities through an investigation of the presence of H I absorption around the terminal velocity. New kinematic distance determinations can be used to further constrain spiral arm parameters and the location and extent of other structures in the Milky Way disk. H I absorption toward continuum sources beyond the solar circle is also investigated. Follow-up studies of H I at higher resolution than the 1' to 2' of existing Galactic Plane Surveys will provide kinematic distances to many more H II regions on the far side of the Galactic center. On the basis of the velocity channel summation technique developed in this paper, a much larger sample of H II regions will be analyzed in a future paper to remove the near-far distance ambiguity.

  20. Compton Effect with Non-Relativistic Kinematics

    ERIC Educational Resources Information Center

    Shivalingaswamy, T.; Kagali, B. A.

    2011-01-01

    In deducing the change of wavelength of x-rays scattered by atomic electrons, one normally makes use of relativistic kinematics for electrons. However, recoiling energies of the electrons are of the order of a few keV which is less than 0.2% of their rest energies. Hence the authors may ask whether relativistic formulae are really necessary. In…

  1. Kinematic Measurements from YouTube Videos

    ERIC Educational Resources Information Center

    Ruiz, Michael J.

    2009-01-01

    Video analysis of motion has been in use now for some time. However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers.…

  2. The kinematic algebras from the scattering equations

    NASA Astrophysics Data System (ADS)

    Monteiro, Ricardo; O'Connell, Donal

    2014-03-01

    We study kinematic algebras associated to the recently proposed scattering equations, which arise in the description of the scattering of massless particles. In particular, we describe the role that these algebras play in the BCJ duality between colour and kinematics in gauge theory, and its relation to gravity. We find that the scattering equations are a consistency condition for a self-dual-type vertex which is associated to each solution of those equations. We also identify an extension of the anti-self-dual vertex, such that the two vertices are not conjugate in general. Both vertices correspond to the structure constants of Lie algebras. We give a prescription for the use of the generators of these Lie algebras in trivalent graphs that leads to a natural set of BCJ numerators. In particular, we write BCJ numerators for each contribution to the amplitude associated to a solution of the scattering equations. This leads to a decomposition of the determinant of a certain kinematic matrix, which appears naturally in the amplitudes, in terms of trivalent graphs. We also present the kinematic analogues of colour traces, according to these algebras, and the associated decomposition of that determinant.

  3. Whole Spontaneous Spinal Epidural Hematoma

    PubMed Central

    Yoon, Kyeong-Wook; Song, Jae Gyok; Ryu, Jae-Wook

    2014-01-01

    A 26-year-old male who had no underlying disease, including coagulopathy, underwent thoracotomy and bleeding control due to hemothorax. On the fifth postoperative day, paralysis of both lower limbs occurred. Urgent spine magnetic resonance imaging showed a massive anterior spinal epidural hematoma from C2 to L1 level with different signal intensities, which was suspected to be staged hemorrhage. Hematoma evacuation with decompressive laminectomy was performed. The patient's neurologic deterioration was recovered immediately, and he was discharged without neurological deficits. A drug history of naftazone, which could induce a drug-induced platelet dysfunction, was revealed retrospectively. To our knowledge, this is the first report of whole spontaneous spinal epidural hematoma in a young patient, with a history of hemorrhoid medication. PMID:24967052

  4. Spontaneous Spinal Epidural Hematoma Report.

    PubMed

    Kukreja, Sunil; Nanda, Anil

    2016-01-01

    We report a case of spontaneous spinal epidural hematoma in a 12-year-old female, who presented with significant upper and lower extremities weakness preceded by pain around the neck and shoulder girdle. Magnetic resonance imaging revealed epidural hematoma extending from C6-T2 with characteristic heterogeneously hyperintensity on T2 and homogenously isointensity on T1. Emergent spinal decompression was performed. However, the patient remained substantially weak in her lower extremities and was wheelchair bound at 3 months postoperatively. We have discussed clinical features, predisposing events, pathogenesis and treatment guidelines described in the literature. We also aim to reinforce the notion of keeping a high degree of clinical suspicion to identify and intervene at the earliest stage to prevent the physically and socially challenging consequences of SSEH. PMID:27598898

  5. Acquired spondylolysis after spinal fusion.

    PubMed

    Brunet, J A; Wiley, J J

    1984-11-01

    Spondylolysis occurring after a spinal fusion is considered to result from operative damage to the pars interarticularis on both sides. Fourteen cases are reported, and compared with the 23 cases which have previously been published. The defects are usually recognised within five years of fusion, and usually occur immediately above the fusion mass. Other contributory causes may be: fatigue fracture from concentration of stress; damage and altered function of the posterior ligament complex; and degenerative disc disease immediately above or below the fusion. Fusion technique is critical, since virtually all cases occurred after posterior interlaminar fusions. This complication is easily overlooked in patients with recurrent back pain after an originally successful posterior spinal fusion. PMID:6501368

  6. Ganglioglioma of the Spinal Cord

    PubMed Central

    Oppenheimer, Daniel C; Johnson, Mahlon D; Judkins, Alexander R

    2015-01-01

    Ganglioglioma is a rare tumor consisting of neoplastic glial and neuronal elements. It accounts for only 0.5% of all primary central nervous system (CNS) neoplasms. We report an unusual case of extensive intramedullary thoracic spinal cord ganglioglioma in a 14-month-old girl who underwent subtotal resection followed by adjuvant chemotherapy. The epidemiology, histopathologic features, imaging findings, treatment, and prognosis are subsequently reviewed. PMID:26605127

  7. Advanced control schemes and kinematic analysis for a kinematically redundant 7 DOF manipulator

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Zhou, Zhen-Lei

    1990-01-01

    The kinematic analysis and control of a kinematically redundant manipulator is addressed. The manipulator is the slave arm of a telerobot system recently built at Goddard Space Flight Center (GSFC) to serve as a testbed for investigating research issues in telerobotics. A forward kinematic transformation is developed in its most simplified form, suitable for real-time control applications, and the manipulator Jacobian is derived using the vector cross product method. Using the developed forward kinematic transformation and quaternion representation of orientation matrices, we perform computer simulation to evaluate the efficiency of the Jacobian in converting joint velocities into Cartesian velocities and to investigate the accuracy of Jacobian pseudo-inverse for various sampling times. The equivalence between Cartesian velocities and quaternion is also verified using computer simulation. Three control schemes are proposed and discussed for controlling the motion of the slave arm end-effector.

  8. The Maiden Voyage of a Kinematics Robot

    NASA Astrophysics Data System (ADS)

    Greenwolfe, Matthew L.

    2015-04-01

    In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K).

  9. Kinematic and Spatial Substructure in NGC 2264

    NASA Astrophysics Data System (ADS)

    Tobin, John J.; Hartmann, Lee; Fűrész, Gabor; Hsu, Wen-Hsin; Mateo, Mario

    2015-04-01

    We present an expanded kinematic study of the young cluster NGC 2264 based upon optical radial velocities measured using multi-fiber echelle spectroscopy at the 6.5 m MMT and Magellan telescopes. We report radial velocities for 695 stars, of which approximately 407 stars are confirmed or very likely members. Our results more than double the number of members with radial velocities from Fűrész et al., resulting in a much better defined kinematic relationship between the stellar population and the associated molecular gas. In particular, we find that there is a significant subset of stars that are systematically blueshifted with respect to the molecular (13CO) gas. The detection of Lithium absorption and/or infrared excesses in this blueshifted population suggests that at least some of these stars are cluster members; we suggest some speculative scenarios to explain their kinematics. Our results also more clearly define the redshifted population of stars in the northern end of the cluster; we suggest that the stellar and gas kinematics of this region are the result of a bubble driven by the wind from O7 star S Mon. Our results emphasize the complexity of the spatial and kinematic structure of NGC 2264, important for eventually building up a comprehensive picture of cluster formation. Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  10. Three-dimensional kinematics of hummingbird flight.

    PubMed

    Tobalske, Bret W; Warrick, Douglas R; Clark, Christopher J; Powers, Donald R; Hedrick, Tyson L; Hyder, Gabriel A; Biewener, Andrew A

    2007-07-01

    Hummingbirds are specialized for hovering flight, and substantial research has explored this behavior. Forward flight is also important to hummingbirds, but the manner in which they perform forward flight is not well documented. Previous research suggests that hummingbirds increase flight velocity by simultaneously tilting their body angle and stroke-plane angle of the wings, without varying wingbeat frequency and upstroke: downstroke span ratio. We hypothesized that other wing kinematics besides stroke-plane angle would vary in hummingbirds. To test this, we used synchronized high-speed (500 Hz) video cameras and measured the three-dimensional wing and body kinematics of rufous hummingbirds (Selasphorus rufus, 3 g, N=5) as they flew at velocities of 0-12 m s(-1) in a wind tunnel. Consistent with earlier research, the angles of the body and the stroke plane changed with velocity, and the effect of velocity on wingbeat frequency was not significant. However, hummingbirds significantly altered other wing kinematics including chord angle, angle of attack, anatomical stroke-plane angle relative to their body, percent of wingbeat in downstroke, wingbeat amplitude, angular velocity of the wing, wingspan at mid-downstroke, and span ratio of the wingtips and wrists. This variation in bird-centered kinematics led to significant effects of flight velocity on the angle of attack of the wing and the area and angles of the global stroke planes during downstroke and upstroke. We provide new evidence that the paths of the wingtips and wrists change gradually but consistently with velocity, as in other bird species that possess pointed wings. Although hummingbirds flex their wings slightly at the wrist during upstroke, their average wingtip-span ratio of 93% revealed that they have kinematically ;rigid' wings compared with other avian species. PMID:17575042

  11. Kinematic Optimization in Birds, Bats and Ornithopters

    NASA Astrophysics Data System (ADS)

    Reichert, Todd

    Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

  12. Surgical Outcome of Spinal Neurilemmoma

    PubMed Central

    Yeh, Kuang-Ting; Lee, Ru-Ping; Yu, Tzai-Chiu; Chen, Ing-Ho; Peng, Cheng-Huan; Liu, Kuan-Lin; Wang, Jen-Hung; Wu, Wen-Tien

    2015-01-01

    Abstract Neurilemmoma commonly occurs from the fourth to sixth decades of life with an incidence of 3 to 10 per 100,000 people, and is rare in adolescence. This case report describes the clinical and radiographic features of 2 rare cases with intraspinal neurilemmoma of the cervical and thoracic spine. A 29-year-old man who experienced middle back pain with prominent right lower limb weakness, and an 11-year-old boy who suffered from sudden onset neck pain with left arm weakness and hand clawing for 2 weeks before admission to our department were included in this case report. Magnetic resonance imaging of both patients revealed an intraspinal mass causing spinal cord compression at the cervical and thoracic spine. The patients subsequently received urgent posterior spinal cord decompression and tumor resection surgery. The histopathology reports revealed neurilemmoma. The 2 patients recovered and resumed their normal lives within 1 year. Intraspinal neurilemmoma is rare but should be considered in the differential diagnosis of spinal cord compression. Advances in imaging techniques and surgical procedures have yielded substantially enhanced clinical outcomes in intraspinal neoplasm cases. Delicate preoperative study and surgical skill with rehabilitation and postoperative observation are critical. PMID:25654395

  13. Spinal myoclonus resembling belly dance.

    PubMed

    Kono, I; Ueda, Y; Araki, K; Nakajima, K; Shibasaki, H

    1994-05-01

    A 63-year-old man presented with an 11-month history of progressive myoclonus in the right abdominal wall. Administration of clonazepam reduced the frequency and amplitude. When the therapy was discontinued, the frequency and amplitude of the myoclonus increased, and synchronous and weak myoclonus also was observed in the left abdomen. The trunk was twisted just after the appearance of the abdominal myoclonus associated with myoclonic jerks spreading from the rostral to caudal paraspinal muscles. Later in the clinical course, the myoclonus became stimulus sensitive and was induced by tendon tap given anywhere on the body, with the latency ranging from 50 to 150 ms irrespective of the sites of tapping. Myoclonus seen in the abdominal wall was segmental and considered to be of spinal origin. The reflex myoclonus had a 150-ms refractory period. It can be postulated that increased excitability of anterior horn cells at a certain segment might make a spino-bulbo-spinal reflex manifest at the corresponding segment. This myoclonus is considered to be a new form of spinal reflex myoclonus, because the abdominal myoclonic jerk seems to trigger another myoclonic jerk involving the paraspinal muscles. PMID:8041373

  14. The importance of maintaining spinal precautions.

    PubMed

    Freeborn, Kellie

    2005-01-01

    Spinal injuries are devastating, often leaving the patient paralyzed or with a permanent deficit. Aspiring athletes may not be able to persue their dreams secondary to a spinal injury; families are often left without a major wage earner to support them; and individuals are dependent upon others for the fulfillment of their basic needs. Education is essential for the prevention of primary and secondary spinal injuries; nurses play a key role in both these areas. PMID:15875449

  15. Management of acute spinal cord injury.

    PubMed

    Wagner, F C

    1977-06-01

    Based on the experience with 58 patients with acute spinal cord injuries, a system for rapidly evaluating such patients has been developed. With the knowledge that has been acquired clinically and experimentally of spinal cord injury and with the information provided by laminography and by either air or Pantopaque myelography, a reasonably certain diagnosis of the type of spinal cord injury may be made. Treatment designed to restore neurological function may then be instituted promptly. PMID:882906

  16. How Are Brain and Spinal Cord Tumors in Children Diagnosed?

    MedlinePlus

    ... spinal cord tumors in children staged? How are brain and spinal cord tumors diagnosed in children? Brain ... resonance angiography (MRA) or computerized tomographic angiography (CTA). Brain or spinal cord tumor biopsy Imaging tests such ...

  17. Testosterone Plus Finasteride Treatment After Spinal Cord Injury

    ClinicalTrials.gov

    2016-07-07

    Spinal Cord Injury; Spinal Cord Injuries; Trauma, Nervous System; Wounds and Injuries; Central Nervous System Diseases; Nervous System Diseases; Spinal Cord Diseases; Gonadal Disorders; Endocrine System Diseases; Hypogonadism; Genital Diseases, Male

  18. Spinal meningiomas: surgical management and outcome.

    PubMed

    Gottfried, Oren N; Gluf, Wayne; Quinones-Hinojosa, Alfredo; Kan, Peter; Schmidt, Meic H

    2003-06-15

    Advances in imaging and surgical technique have improved the treatment of spinal meningiomas; these include magnetic resonance imaging, intraoperative ultrasonography, neuromonitoring, the operative microscope, and ultrasonic cavitation aspirators. This study is a retrospective review of all patients treated at a single institution and with a pathologically confirmed diagnosis of spinal meningioma. Additionally the authors analyze data obtained in 556 patients reported in six large series in the literature, evaluating surgical techniques, results, and functional outcomes. Overall, surgical treatment of spinal meningiomas is associated with favorable outcomes. Spinal meningiomas can be completely resected, are associated with postoperative functional improvement, and the rate of recurrence is low. PMID:15669787

  19. Neurologic foundations of spinal cord fusion (GEMINI).

    PubMed

    Canavero, Sergio; Ren, XiaoPing; Kim, C-Yoon; Rosati, Edoardo

    2016-07-01

    Cephalosomatic anastomosis has been carried out in both monkeys and mice with preservation of brain function. Nonetheless the spinal cord was not reconstructed, leaving the animals unable to move voluntarily. Here we review the details of the GEMINI spinal cord fusion protocol, which aims at restoring electrophysiologic conduction across an acutely transected spinal cord. The existence of the cortico-truncoreticulo-propriospinal pathway, a little-known anatomic entity, is described, and its importance concerning spinal cord fusion emphasized. The use of fusogens and electrical stimulation as adjuvants for nerve fusion is addressed. The possibility of achieving cephalosomatic anastomosis in humans has become reality in principle. PMID:27180142

  20. Focused review: spinal anesthesia in severe preeclampsia.

    PubMed

    Henke, Vanessa G; Bateman, Brian T; Leffert, Lisa R

    2013-09-01

    Spinal anesthesia is widely regarded as a reasonable anesthetic option for cesarean delivery in severe preeclampsia, provided there is no indwelling epidural catheter or contraindication to neuraxial anesthesia. Compared with healthy parturients, those with severe preeclampsia experience less frequent, less severe spinal-induced hypotension. In severe preeclampsia, spinal anesthesia may cause a higher incidence of hypotension than epidural anesthesia; however, this hypotension is typically easily treated and short lived and has not been linked to clinically significant differences in outcomes. In this review, we describe the advantages and limitations of spinal anesthesia in the setting of severe preeclampsia and the evidence guiding intraoperative hemodynamic management. PMID:23868886

  1. Upper Limb Assessment in Tetraplegia: Clinical, Functional and Kinematic Correlations

    ERIC Educational Resources Information Center

    Cacho, Enio Walker Azevedo; de Oliveira, Roberta; Ortolan, Rodrigo L.; Varoto, Renato; Cliquet, Alberto

    2011-01-01

    The aim of this study was to correlate clinical and functional evaluations with kinematic variables of upper limp reach-to-grasp movement in patients with tetraplegia. Twenty chronic patients were selected to perform reach-to-grasp kinematic assessment using a target placed at a distance equal to the arm's length. Kinematic variables (hand peak…

  2. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... tumor, and failed previous fusion (pseudarthrosis). The safety and effectiveness of these devices...

  3. Lumbar spinal loading during bowling in cricket: a kinetic analysis using a musculoskeletal modelling approach.

    PubMed

    Zhang, Yanxin; Ma, Ye; Liu, Guangyu

    2016-06-01

    The objective of the study was to evaluate two types of cricket bowling techniques by comparing the lumbar spinal loading using a musculoskeletal modelling approach. Three-dimensional kinematic data were recorded by a Vicon motion capture system under two cricket bowling conditions: (1) participants bowled at their absolute maximal speeds (max condition), and (2) participants bowled at their absolute maximal speeds while simultaneously forcing their navel down towards their thighs starting just prior to ball release (max-trunk condition). A three-dimensional musculoskeletal model comprised of the pelvis, sacrum, lumbar vertebrae and torso segments, which enabled the motion of the individual lumbar vertebrae in the sagittal, frontal and coronal planes to be actuated by 210 muscle-tendon units, was used to simulate spinal loading based on the recorded kinematic data. The maximal lumbar spine compressive force is 4.89 ± 0.88BW for the max condition and 4.58 ± 0.54BW for the max-trunk condition. Results showed that there was no significant difference between the two techniques in trunk moments and lumbar spine forces. This indicates that the max-trunk technique may not increase lower back injury risks. The method proposed in this study could be served as a tool to evaluate lower back injury risks for cricket bowling as well as other throwing activities. PMID:26343905

  4. Are there a guidelines for implantable spinal cord stimulator therapy in patients using chronic anticoagulation therapy? - A review of decision-making in the high-risk patient

    PubMed Central

    Ghaly, Ramsis F.; Lissounov, Alexei; Candido, Kenneth D.; Knezevic, Nebojsa Nick

    2016-01-01

    Background: Spinal cord stimulators (SCSs) are gaining increasing indications and utility in an expanding variety of clinical conditions. Complications and initial expenses have historically prevented the early use of SCS therapy despite ongoing efforts to educate and promote its utilization. At present, there exists no literature evidence of SCS implantation in a chronically anticoagulated patient, and neuromodulation manufacturers are conspicuously silent in providing warnings or recommendations in the face of anticoagulant use chronically. It would appear as through these issues demand scrutiny and industry as well as neuromodulation society advocacy and support in terms of the provision of coherent guidelines on how to proceed. Case Description: A 79-year-old male returned to the neurosurgical clinic with persistent low back pain and leg heaviness due to adjacent level degenerative spondylosis and severe thoracic spinal stenosis. The patient had a notable history of multiple comorbidities along with atrial fibrillation requiring chronic anticoagulation. On initial presentation, he was educated with three choice of conservative medical therapy, intrathecal drug delivery system implantation, or additional lumbar decompression laminectomy with instrumented fusion of T10-L3 and a palliative surgical lead SCS implantation. Description: A 79-year-old male returned to the neurosurgical clinic with persistent low back pain and leg heaviness due to adjacent level degenerative spondylosis and severe thoracic spinal stenosis. The patient had a notable history of multiple comorbidities along with atrial fibrillation requiring chronic anticoagulation. On initial presentation, he was educated with three choice of conservative medical therapy, intrathecal drug delivery system implantation, or additional lumbar decompression laminectomy with instrumented fusion of T10-L3 and a palliative surgical lead SCS implantation. Conclusion: Our literature search did not reveal any

  5. Shoulder Pain and Cycle to Cycle Kinematic Spatial Variability during Recovery Phase in Manual Wheelchair Users: A Pilot Investigation

    PubMed Central

    Jayaraman, Chandrasekaran; Moon, Yaejin; Rice, Ian M.; Hsiao Wecksler, Elizabeth T.; Beck, Carolyn L.; Sosnoff, Jacob J.

    2014-01-01

    Wheelchair propulsion plays a significant role in the development of shoulder pain in manual wheelchair users (MWU). However wheelchair propulsion metrics related to shoulder pain are not clearly understood. This investigation examined intra-individual kinematic spatial variability during semi-circular wheelchair propulsion as a function of shoulder pain in MWU. Data from 10 experienced adult MWU with spinal cord injury (5 with shoulder pain; 5 without shoulder pain) were analyzed in this study. Participants propelled their own wheelchairs on a dynamometer at 3 distinct speeds (self-selected, 0.7 m/s, 1.1 m/s) for 3 minutes at each speed. Motion capture data of the upper limbs were recorded. Intra-individual kinematic spatial variability of the steady state wrist motion during the recovery phase was determined using principal component analysis (PCA). The kinematic spatial variability was calculated at every 10% intervals (i.e at 11 interval points, from 0% to 100%) along the wrist recovery path. Results Overall, spatial variability was found to be highest at the start and end of the recovery phase and lowest during the middle of the recovery path. Individuals with shoulder pain displayed significantly higher kinematic spatial variability than individuals without shoulder pain at the start (at 10% interval) of the recovery phase (p<.004). Conclusions Analysis of intra-individual kinematic spatial variability during the recovery phase of manual wheelchair propulsion distinguished between those with and without shoulder pain. Variability analysis of wheelchair propulsion may offer a new approach to monitor the development and rehabilitation of shoulder pain. PMID:24614232

  6. Fetal segmental spinal dysgenesis and unusual segmental agenesis of the anterior spinal artery.

    PubMed

    Valdez Quintana, Melissa; Michaud, Jean; El-Chaar, Darine; El Demellawy, Dina; Nikkel, Sarah M; Miller, Elka

    2016-08-01

    Segmental spinal dysgenesis (SSD) is a rare congenital spinal abnormality characterized by segmental dysgenesis or agenesis of the thoracolumbar or lumbar spine, congenital kyphosis, and abnormal configuration of the underlying spinal cord. A unique feature of SSD is that the vertebrae are present above and below the defect, and there is often a lower cord segment in the caudal spinal canal. We report a fetal MRI case of SSD with postmortem and neuropathological correlations. Our report confirms already published findings including the presence of a neurenteric cyst but is the first to document anterior spinal artery segmental agenesis in SSD. PMID:26969176

  7. Spinal Tuberculosis (Pott's disease) Mimicking Paravertebral Malignant Tumor in a Child Presenting with Spinal Cord Compression

    PubMed Central

    Emir, Suna; Erdem, Arzu Y; Demir, Haci A; Kaçar, Ayper; Tunç, Bahattin

    2012-01-01

    Paravertebral tumors may interfere with the radiological and clinical features of spinal tuberculosis. We report a case of a 3-year-old boy with spinal tuberculosis who was initially misdiagnosed as having a paraspinal tumor. The diagnosis of tuberculosis was made on the basis of intraoperative findings and confirmed by histopathology. This case highlights the importance of awareness of the different radiographic features of spinal tuberculosis, which can mimic a spinal malignancy. In order to avoid delayed diagnosis, pediatricians and radiologists must be aware of spinal tuberculosis, which may interfere with other clinical conditions. PMID:23439455

  8. Acute effects of Dry Immersion on kinematic characteristics of postural corrective responses

    NASA Astrophysics Data System (ADS)

    Sayenko, D. G.; Miller, T. F.; Melnik, K. A.; Netreba, A. I.; Khusnutdinova, D. R.; Kitov, V. V.; Tomilovskaya, E. S.; Reschke, M. F.; Gerasimenko, Y. P.; Kozlovskaya, I. B.

    2016-04-01

    Impairments in balance control are inevitable following exposure to microgravity. However, the role of particular sensory system in postural disorders at different stages of the exposure to microgravity still remains unknown. We used a method called Dry Immersion (DI), as a ground-based model of microgravity, to elucidate the effects of 6-h of load-related afferent inputs on kinematic characteristics of postural corrective responses evoked by pushes to the chest of different intensities during upright standing. The structure of postural corrective responses was altered following exposure to DI, which was manifested by: (1) an increase of the ankle and knee flexion during perturbations of medium intensity, (2) the lack of the compensatory hip extension, as well as diminished knee and ankle flexion with a further increase of the perturbation intensity to submaximal level. We suggest that the lack of weight-bearing increases the reactivity of the balance control system, whereas the ability to scale the responses proportionally to the perturbation intensity decreases. Disrupted neuromuscular coordination of postural corrective responses following DI can be attributed to adaptive neural modifications on the spinal and cortical levels. The present study provides evidence that even a short-term lack of load-related afferent inputs alters kinematic patterns of postural corrective responses, and can result in decreased balance control. Because vestibular input is not primarily affected during the DI exposure, our results indicate that activity and the state of the load-related afferents play critical roles in balance control following real or simulated microgravity.

  9. Spine Kinematics During Prone Extension in People With and Without Low Back Pain and Among Classification-Specific Low Back Pain Subgroups.

    PubMed

    Mazzone, Brittney; Wood, Ron; Gombatto, Sara

    2016-07-01

    Study Design Cross-sectional observational design. Background Spine extension is used in physical therapy during examination and treatment for low back pain (LBP). However, kinematics during prone extension have not been examined using 3-D motion capture. Objectives The primary purpose was to determine differences in spine kinematics during prone extension between subjects with and without LBP. An exploratory analysis was conducted to examine kinematic differences among LBP subgroups. Methods Kinematics of the thoracic and lumbar spine were examined during prone extension, using optical motion capture, in 18 subjects with LBP and 17 subjects without LBP (control group). Excursion of each spinal region was calculated for the entire movement and during 25% increments of extension movement duration. Subjects with LBP were examined and assigned to subgroups using 3 different classification systems for LBP. Repeated-measures analysis-of-variance tests were used to examine effects of group (LBP, control), spine region, and increment of movement duration, and to explore effects of LBP subgroup. Results For spine kinematics, there was a significant group-by-region interaction effect (P<.05). Subjects with LBP displayed less lower lumbar extension (13.3° ± 4.9°) than control subjects (21.4° ± 9.2°). The majority of lower lumbar extension occurred during the first 50% of the motion for subjects with LBP. Subgroup-by-region interaction effects were significant for 2 of 3 LBP classification systems (P<.05). Conclusion Subjects with LBP displayed less lower lumbar extension than control subjects during prone extension. These differences should be considered when evaluating and prescribing prone extension. The interpretation of subgroup differences with prone extension kinematics is limited in the current study by the small sample size, but may need to be considered in future studies of spine kinematics. Level of Evidence Diagnosis, level 4. J Orthop Sports Phys Ther 2016

  10. The kinematic advantage of electric cars

    NASA Astrophysics Data System (ADS)

    Meyn, Jan-Peter

    2015-11-01

    Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h-1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.

  11. A classification of finite quantum kinematics

    NASA Astrophysics Data System (ADS)

    Tolar, J.

    2014-10-01

    Quantum mechanics in Hilbert spaces of finite dimension N is reviewed from the number theoretic point of view. For composite numbers N possible quantum kinematics are classified on the basis of Mackey's Imprimitivity Theorem for finite Abelian groups. This yields also a classification of finite Weyl-Heisenberg groups and the corresponding finite quantum kinematics. Simple number theory gets involved through the fundamental theorem describing all finite discrete Abelian groups of order N as direct products of cyclic groups, whose orders are powers of not necessarily distinct primes contained in the prime decomposition of N. The representation theoretic approach is further compared with the algebraic approach, where the basic object is the corresponding operator algebra. The consideration of fine gradings of this associative algebra then brings a fresh look on the relation between the mathematical formalism and physical realizations of finite quantum systems.

  12. Kinematic measurements using an infrared sensor

    NASA Astrophysics Data System (ADS)

    Marinho, F.; Paulucci, L.

    2016-03-01

    The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4-30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems.

  13. Spinal circuits can accommodate interaction torques during multijoint limb movements

    PubMed Central

    Buhrmann, Thomas; Di Paolo, Ezequiel A.

    2014-01-01

    The dynamic interaction of limb segments during movements that involve multiple joints creates torques in one joint due to motion about another. Evidence shows that such interaction torques are taken into account during the planning or control of movement in humans. Two alternative hypotheses could explain the compensation of these dynamic torques. One involves the use of internal models to centrally compute predicted interaction torques and their explicit compensation through anticipatory adjustment of descending motor commands. The alternative, based on the equilibrium-point hypothesis, claims that descending signals can be simple and related to the desired movement kinematics only, while spinal feedback mechanisms are responsible for the appropriate creation and coordination of dynamic muscle forces. Partial supporting evidence exists in each case. However, until now no model has explicitly shown, in the case of the second hypothesis, whether peripheral feedback is really sufficient on its own for coordinating the motion of several joints while at the same time accommodating intersegmental interaction torques. Here we propose a minimal computational model to examine this question. Using a biomechanics simulation of a two-joint arm controlled by spinal neural circuitry, we show for the first time that it is indeed possible for the neuromusculoskeletal system to transform simple descending control signals into muscle activation patterns that accommodate interaction forces depending on their direction and magnitude. This is achieved without the aid of any central predictive signal. Even though the model makes various simplifications and abstractions compared to the complexities involved in the control of human arm movements, the finding lends plausibility to the hypothesis that some multijoint movements can in principle be controlled even in the absence of internal models of intersegmental dynamics or learned compensatory motor signals. PMID:25426061

  14. Missing Mass Measurement Using Kinematic Cusp

    SciTech Connect

    Kim, Ian-Woo

    2010-02-10

    We propose a new method for mass measurement of missing energy particle using cusp structure in the kinematic distribution. We consider a resonance particle decay into a pair of missing energy particles and a pair of visible particles and show invariant mass and angular distribution have non-smooth profiles. The cusp location only depends on mass parameters. Invariant mass and angular distribution are complementary in visibility of the cusp.

  15. Analyzing Robotic Kinematics Via Computed Simulations

    NASA Technical Reports Server (NTRS)

    Carnahan, Timothy M.

    1992-01-01

    Computing system assists in evaluation of kinematics of conceptual robot. Displays positions and motions of robotic manipulator within work cell. Also displays interactions between robotic manipulator and other objects. Results of simulation displayed on graphical computer workstation. System includes both off-the-shelf software originally developed for automotive industry and specially developed software. Simulation system also used to design human-equivalent hand, to model optical train in infrared system, and to develop graphical interface for teleoperator simulation system.

  16. Kinematics of Phase Boundary Growth. Directional Solidification

    NASA Astrophysics Data System (ADS)

    Radev, Krassimir B.

    2010-01-01

    This report aims to give consideration to the time-space evolution of the phase boundary by making use of the kinematic condition on the interface, representing the balance of the mass fluxes through the movable growing boundary, as well as the Gibbs-Thompson condition of the local phase equilibrium. The analysis has shown the determinative role of a dimensionles parameter—combination of only physical properties of the system—on the evolution of surface fluctuations.

  17. Kinematics of Hooke universal joint robot wrists

    NASA Technical Reports Server (NTRS)

    Mckinney, William S., Jr.

    1988-01-01

    The singularity problem associated with wrist mechanisms commonly found on industrial manipulators can be alleviated by redesigning the wrist so that it functions as a three-axis gimbal system. This paper discussess the kinematics of gimbal robot wrists made of one and two Hooke universal joints. Derivations of the resolved rate motion control equations for the single and double Hooke universal joint wrists are presented using the three-axis gimbal system as a theoretical wrist model.

  18. Lower extremity kinematics of athletics curve sprinting.

    PubMed

    Alt, Tobias; Heinrich, Kai; Funken, Johannes; Potthast, Wolfgang

    2015-01-01

    Curve running requires the generation of centripetal force altering the movement pattern in comparison to the straight path run. The question arises which kinematic modulations emerge while bend sprinting at high velocities. It has been suggested that during curve sprints the legs fulfil different functions. A three-dimensional motion analysis (16 high-speed cameras) was conducted to compare the segmental kinematics of the lower extremity during the stance phases of linear and curve sprints (radius: 36.5 m) of six sprinters of national competitive level. Peak joint angles substantially differed in the frontal and transversal plane whereas sagittal plane kinematics remained unchanged. During the prolonged left stance phase (left: 107.5 ms, right: 95.7 ms, straight: 104.4 ms) the maximum values of ankle eversion (left: 12.7°, right: 2.6°, straight: 6.6°), hip adduction (left: 13.8°, right: 5.5°, straight: 8.8°) and hip external rotation (left: 21.6°, right: 12.9°, straight: 16.7°) were significantly higher. The inside leg seemed to stabilise the movement in the frontal plane (eversion-adduction strategy) whereas the outside leg provided and controlled the motion in the horizontal plane (rotation strategy). These results extend the principal understanding of the effects of curve sprinting on lower extremity kinematics. This helps to increase the understanding of nonlinear human bipedal locomotion, which in turn might lead to improvements in athletic performance and injury prevention. PMID:25495196

  19. High precision kinematic surveying with laser scanners

    NASA Astrophysics Data System (ADS)

    Gräfe, Gunnar

    2007-12-01

    The kinematic survey of roads and railways is becoming a much more common data acquisition method. The development of the Mobile Road Mapping System (MoSES) has reached a level that allows the use of kinematic survey technology for high precision applications. The system is equipped with cameras and laser scanners. For high accuracy requirements, the scanners become the main sensor group because of their geometric precision and reliability. To guarantee reliable survey results, specific calibration procedures have to be applied, which can be divided into the scanner sensor calibration as step 1, and the geometric transformation parameter estimation with respect to the vehicle coordinate system as step 2. Both calibration steps include new methods for sensor behavior modeling and multisensor system integration. To verify laser scanner quality of the MoSES system, the results are regularly checked along different test routes. It can be proved that a standard deviation of 0.004 m for height of the scanner points will be obtained, if the specific calibrations and data processing methods are applied. This level of accuracy opens new possibilities to serve engineering survey applications using kinematic measurement techniques. The key feature of scanner technology is the full digital coverage of the road area. Three application examples illustrate the capabilities. Digital road surface models generated from MoSES data are used, especially for road surface reconstruction tasks along highways. Compared to static surveys, the method offers comparable accuracy at higher speed, lower costs, much higher grid resolution and with greater safety. The system's capability of gaining 360 profiles leads to other complex applications like kinematic tunnel surveys or the precise analysis of bridge clearances.

  20. Intraoperative neurophysiological monitoring in spinal surgery.

    PubMed

    Park, Jong-Hwa; Hyun, Seung-Jae

    2015-09-16

    Recently, many surgeons have been using intraoperative neurophysiological monitoring (IOM) in spinal surgery to reduce the incidence of postoperative neurological complications, including level of the spinal cord, cauda equina and nerve root. Several established technologies are available and combined motor and somatosensory evoked potentials are considered mandatory for practical and successful IOM. Spinal cord evoked potentials are elicited compound potentials recorded over the spinal cord. Electrical stimulation is provoked on the dorsal spinal cord from an epidural electrode. Somatosensory evoked potentials assess the functional integrity of sensory pathways from the peripheral nerve through the dorsal column and to the sensory cortex. For identification of the physiological midline, the dorsal column mapping technique can be used. It is helpful for reducing the postoperative morbidity associated with dorsal column dysfunction when distortion of the normal spinal cord anatomy caused by an intramedullary cord lesion results in confusion in localizing the midline for the myelotomy. Motor evoked potentials (MEPs) consist of spinal, neurogenic and muscle MEPs. MEPs allow selective and specific assessment of the functional integrity of descending motor pathways, from the motor cortex to peripheral muscles. Spinal surgeons should understand the concept of the monitoring techniques and interpret monitoring records adequately to use IOM for the decision making during the surgery for safe surgery and a favorable surgical outcome. PMID:26380823

  1. Charcot spinal arthropathy in a diabetic patient.

    PubMed

    van Eeckhoudt, S; Minet, M; Lecouvet, F; Galant, C; Banse, X; Lambert, M; Lefèbvre, C

    2014-08-01

    We report a case of Charcot spinal arthropathy in a diabetic patient and emphasize the clinical reasoning leading to the diagnosis, discuss the differential diagnosis, and insist on the crucial role of the radiologist and pathologist which allows the distinction between Charcot spinal arthropathy and infectious or tumoural disorders of the spine. PMID:25012751

  2. Intraoperative neurophysiological monitoring in spinal surgery

    PubMed Central

    Park, Jong-Hwa; Hyun, Seung-Jae

    2015-01-01

    Recently, many surgeons have been using intraoperative neurophysiological monitoring (IOM) in spinal surgery to reduce the incidence of postoperative neurological complications, including level of the spinal cord, cauda equina and nerve root. Several established technologies are available and combined motor and somatosensory evoked potentials are considered mandatory for practical and successful IOM. Spinal cord evoked potentials are elicited compound potentials recorded over the spinal cord. Electrical stimulation is provoked on the dorsal spinal cord from an epidural electrode. Somatosensory evoked potentials assess the functional integrity of sensory pathways from the peripheral nerve through the dorsal column and to the sensory cortex. For identification of the physiological midline, the dorsal column mapping technique can be used. It is helpful for reducing the postoperative morbidity associated with dorsal column dysfunction when distortion of the normal spinal cord anatomy caused by an intramedullary cord lesion results in confusion in localizing the midline for the myelotomy. Motor evoked potentials (MEPs) consist of spinal, neurogenic and muscle MEPs. MEPs allow selective and specific assessment of the functional integrity of descending motor pathways, from the motor cortex to peripheral muscles. Spinal surgeons should understand the concept of the monitoring techniques and interpret monitoring records adequately to use IOM for the decision making during the surgery for safe surgery and a favorable surgical outcome. PMID:26380823

  3. Psychological Aspects of Spinal Cord Injury

    ERIC Educational Resources Information Center

    Cook, Daniel W.

    1976-01-01

    Reviewing literature on the psychological impact of spinal cord injury suggests: (a) depression may not be a precondition for injury adjustment; (b) many persons sustaining cord injury may have experienced psychological disruption prior to injury; and (c) indexes of rehabilitation success need to be developed for the spinal cord injured. (Author)

  4. Nutrition of People with Spinal Cord Injuries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This conference proceeding summarizes current knowledge about the nutritional status and needs of the spinal cord injured patient. Topics covered include the aspects of spinal cord injury that influence nutrient intakes and status, and the nutrients most likely to be problematic in this diverse gro...

  5. Brain dopamine and kinematics of graphomotor functions.

    PubMed

    Lange, Klaus W; Mecklinger, Lara; Walitza, Susanne; Becker, Georg; Gerlach, Manfred; Naumann, Markus; Tucha, Oliver

    2006-10-01

    Three experiments were performed in an attempt to achieve a better understanding of the effect of dopamine on handwriting. In the first experiment, kinematic aspects of handwriting movements were compared between healthy participants and patients with Parkinson's disease (PD) on their usual dopaminergic treatment and following withdrawal of dopaminergic medication. In the second experiment, the writing performance of healthy participants with a hyperechogenicity of the substantia nigra as detected by transcranial sonography (TCS) was compared with the performance of healthy participants with low echogenicity of the substantia nigra. The third experiment examined the effect of central dopamine reduction on kinematic aspects of handwriting movements in healthy adults using acute phenylalanine and tyrosine depletion (APTD). A digitising tablet was used for the assessment of handwriting movements. Participants were asked to perform a simple writing task. Movement time, distance, velocity, acceleration and measures of fluency of handwriting movements were measured. The kinematic analysis of handwriting movements revealed that alterations of central dopaminergic neurotransmission adversely affect movement execution during handwriting. In comparison to the automatic processing of handwriting movements displayed by control participants, participants with an altered dopaminergic neurotransmission shifted from an automatic to a controlled processing of movement execution. Central dopamine appears to be of particular importance with regard to the automatic execution of well-learned movements. PMID:16859791

  6. Scapula Kinematics of Youth Baseball Players

    PubMed Central

    Oliver, Gretchen; Weimar, Wendi

    2015-01-01

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. PMID:26839605

  7. Scapula Kinematics of Youth Baseball Players.

    PubMed

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. PMID:26839605

  8. Kinematic adaptations to tripedal locomotion in dogs.

    PubMed

    Goldner, B; Fuchs, A; Nolte, I; Schilling, N

    2015-05-01

    Limb amputation often represents the only treatment option for canine patients with certain diseases or injuries of the appendicular system. Previous studies have investigated adaptations to tripedal locomotion in dogs but there is a lack of understanding of biomechanical compensatory mechanisms. This study evaluated the kinematic differences between quadrupedal and tripedal locomotion in nine healthy dogs running on a treadmill. The loss of the right pelvic limb was simulated using an Ehmer sling. Kinematic gait analysis included spatio-temporal comparisons of limb, joint and segment angles of the remaining pelvic and both thoracic limbs. The following key parameters were compared between quadrupedal and tripedal conditions: angles at touch-down and lift-off, minimum and maximum joint angles, plus range of motion. Significant differences in angular excursion were identified in several joints of each limb during both stance and swing phases. The most pronounced differences concerned the remaining pelvic limb, followed by the contralateral thoracic limb and, to a lesser degree, the ipsilateral thoracic limb. The thoracic limbs were, in general, more retracted, consistent with pelvic limb unloading and previous observations of bodyweight re-distribution in amputees. Proximal limb segments showed more distinct changes than distal ones. Particularly, the persistently greater anteversion of the pelvis probably affects the axial system. Overall, tripedal locomotion requires concerted kinematic adjustments of both the appendicular and axial systems, and consequently preventive, therapeutic and rehabilitative care of canine amputees should involve the whole musculoskeletal apparatus. PMID:25862392

  9. New Kinematical Constraints on Cosmic Acceleration

    SciTech Connect

    Rapetti, David; Allen, Steve W.; Amin, Mustafa A.; Blandford, Roger; /-KIPAC, Menlo Park

    2007-05-25

    We present and employ a new kinematical approach to ''dark energy'' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the present-day value of the deceleration parameter q{sub 0} and the cosmic jerk parameter, j(t). An elegant feature of this parameterization is that all {Lambda}CDM models have j(t)=1 (constant), which facilitates simple tests for departures from the {Lambda}CDM paradigm. Applying our model to redshift-independent distance measurements, from type Ia supernovae and X-ray cluster gas mass fraction measurements, we obtain clear statistical evidence for a late time transition from a decelerating to an accelerating phase. For a flat model with constant jerk, j(t)=j, we measure q{sub 0}=-0.81 {+-} 0.14 and j=2.16 +0.81 -0.75, results that are consistent with {Lambda}CDM at about the 1{sigma} confidence level. In comparison to dynamical analyses, the kinematical approach uses a different model set and employs a minimum of prior information, being independent of any particular gravity theory. The results obtained with this new approach therefore provide important additional information and we argue that both kinematical and dynamical techniques should be employed in future dark energy studies, where possible.

  10. Epidemiology of spinal cord injury.

    PubMed

    Kurtzke, J F

    1977-01-01

    Accidents are the cause of some 50 deaths per 100 000 population each year in the US; some 3% of these are from traumatic spinal cord injury alone. Traumatic spinal cord injury in socioeconomically advanced countries, has a probably annual incidence rate of 3 per 100 000 population. Males are affected five times as often as females, and in the US, Negroes have twice the rates of whites. Half the cases are due to motor vehicle accidents, 1/4 to falls, and 1/10 to sports injuries. Maximal ages at risk are 15 to 34; only for cord damage due to falls do this risk differ, and here elderly are the more prone. Associated injuries are common in traumatic cord injury, and head injury and pulmonary dysfunction are frequent causes of the acute deaths in traumatic SCI which is why complete quadriplegia has a high early case-fatality ratio. Late deaths in SCI are principally the direct or indirect result of the neurogenic bladder. With treatment in comprehensive spinal cord injury centers, more than 4 of 5 traumatic SCI patients will survive ten years with an average of almost 18 years. Median survival may be almost 14 years for complete quadriplegia, 17 for complete paraplegia, 19 for incomplete quadriplegia, 20 for incomplete paraplegia and 28 for cauda equina lesions. Prevalence is likely to be some 50 per 100 000 population with about 20 per 100 000 completely paralyzed (3 quadriplegic and 19 paraplegic). Some 4 out of 5 survivors of traumatic SCI should be able to live at home and perform gainful work after such treatment. PMID:616527

  11. Sphingolipids in spinal cord injury

    PubMed Central

    Jones, Zachary B; Ren, Yi

    2016-01-01

    Spinal cord injury (SCI) is a debilitating condition that affects millions of individuals worldwide. Despite progress over the last few decades, the molecular mechanisms of secondary SCI that continue to occur days and weeks after the original trauma remain poorly understood. As a result, current therapies for SCI are only marginally effective. Sphingolipids, a diverse class of bioactive lipids, have been shown to regulate SCI repair and key secondary injury processes such as apoptosis, ischemia and inflammation. This review will discuss the numerous roles of sphingolipids and highlight the potential of sphingolipid-targeted therapies for SCI. PMID:27570580

  12. Parasitic and rare spinal infections.

    PubMed

    do Amaral, Lázaro Luís Faria; Nunes, Renato Hoffmann; da Rocha, Antonio Jose

    2015-05-01

    The imaging features of spinal parasitic diseases and other rare infections are herein discussed. These diseases are distributed worldwide, with increased prevalence in areas with poor sanitary conditions and in developing countries. In nonendemic areas, sporadic cases may occur, consequent to increased international travel and immunocompromising conditions. Infectious diseases are usually treatable, and early detection is often crucial. A thorough comprehension of the imaging patterns associated with the clinical features, epidemiology, and laboratory results allows the radiologist to narrow down the options for differential diagnosis and facilitates the timely implementation of appropriate therapies. PMID:25952177

  13. Neuroimaging of Spinal Canal Stenosis.

    PubMed

    Cowley, Peter

    2016-08-01

    Spinal stenosis is common and presents in a variety of forms. Symptomatic lumbar stenosis occurs in approximately 10% of the population and cervical stenosis in 9% over age 70. Imaging is central to the management decision process and first-choice MR imaging may be substituted with CT and CT myelography. A review of the literature is presented with particular emphasis on the clinical-radiologic correlation in both neurogenic intermittent claudication and cervical spondylotic myelopathy. Advanced techniques promise improvements, particularly with radicular compressive lesions, but remain underutilized in routine clinical practice. PMID:27417399

  14. Sphingolipids in spinal cord injury.

    PubMed

    Jones, Zachary B; Ren, Yi

    2016-01-01

    Spinal cord injury (SCI) is a debilitating condition that affects millions of individuals worldwide. Despite progress over the last few decades, the molecular mechanisms of secondary SCI that continue to occur days and weeks after the original trauma remain poorly understood. As a result, current therapies for SCI are only marginally effective. Sphingolipids, a diverse class of bioactive lipids, have been shown to regulate SCI repair and key secondary injury processes such as apoptosis, ischemia and inflammation. This review will discuss the numerous roles of sphingolipids and highlight the potential of sphingolipid-targeted therapies for SCI. PMID:27570580

  15. Extradural spinal synovial cysts in nine dogs.

    PubMed

    Dickinson, P J; Sturges, B K; Berry, W L; Vernau, K M; Koblik, P D; Lecouteur, R A

    2001-10-01

    Nine dogs presenting for investigation of cervical or thoracolumbar myelopathies were diagnosed with extradural spinal synovial cysts. Degenerative disease affecting the articular facets or intervertebral discs was present on plain spinal radiographs in all cases. Myelography was consistent with dorsolateral, extradural spinal cord compression. Two groups of dogs were identified: (1) young, giant breed dogs with multiple cysts involving one or more levels of the cervical spinal cord; and (2) older, large breed dogs with solitary cysts involving the thoracolumbar spinal cord. The synovial cysts constituted the major compressive lesions in four of the dogs. Analysis of lumbar cerebrospinal fluid demonstrated albuminocytological dissociation, consistent with chronic compressive myelopathy, in six dogs. All dogs underwent decompressive surgery and the diagnosis of synovial cysts was confirmed histologically. The mean follow-up period was 17 months (range four to 36 months). At the time of follow-up, all dogs were fully ambulatory with improved neurological function compared with that at initial presentation. PMID:11688527

  16. Computational tool for comparison of kinematic mechanisms and commonly used kinematic models

    SciTech Connect

    Hollerbach, K.; Hollister, A.M.; Van Vorhis, R.L.

    1997-03-01

    Accurate, reliable, and reproducible methods to measure the movements of human joints have been elusive. Currently, three-dimensional recording methods are used to track the motion of one segment relative to another as the joint moves. Six parameters describe the moving segment`s location and orientation relative to the reference segment: three translations (x, y, and z) and three rotations (yaw, pitch and roll) in the reference frame. The raw data can be difficult to interpret. For this reason, several methods have been developed to measure the motion of human joints and to describe the resulting data. For example, instant helical axes or screw deviation axes (Kinzell et al., 1972), the Joint Coordinate System of Grood and Suntay (1983), and the Euler angle method have been used to describe the movements of bones relative to each other. None of these methods takes into account the physical kinematic mechanism producing the joint motion. More recently, Lupichuk (1995) has developed an algorithm to find, for an arbitrary revolute, the axis` position and orientation in three- dimensional space. Each of these methods has advantages and disadvantages in analyzing joint kinematics. The authors have developed software to provide a means of comparing these methods for arbitrary, single degree of freedom, kinematic mechanisms. Our objective is to demonstrate the software and to show how it can be used to compare the results from the different kinematic models as they are applied to specific kinematic mechanisms.

  17. The Stellar Kinematic Fields of NGC 3379

    NASA Astrophysics Data System (ADS)

    Statler, Thomas S.; Smecker-Hane, Tammy

    1999-02-01

    We have measured the stellar kinematic profiles of NGC 3379 along four position angles, using absorption lines in spectra obtained with the Multiple Mirror Telescope. We derive a far more detailed description of the kinematic fields through the main body of the galaxy than could be obtained from previous work. Our data extend 90" from the center, at essentially seeing-limited resolution out to 17". The derived mean velocities and dispersions have total errors (internal and systematic) better than +/-10 km s^-1, and frequently better than 5 km s^-1, out to 55". We find very weak (3 km s^-1) rotation on the minor axis interior to 12" and no detectable rotation above 6 km s^-1 from 12" to 50" or above 16 km s^-1 out to 90" (95% confidence limits). However, a Fourier reconstruction of the mean velocity field from all four sampled PAs does indicate a ~5 deg twist of the kinematic major axis, in the direction opposite to the known isophotal twist. The h_3 and h_4 parameters are found to be generally small over the entire observed region. The azimuthally averaged dispersion profile joins smoothly at large radii with the velocity dispersions of planetary nebulae. Unexpectedly, we find sharp bends in the major axis rotation curve, also visible (though less pronounced) on the diagonal position angles. The outermost bend closely coincides in position with other sharp kinematic features: an abrupt flattening of the dispersion profile, and local peaks in h_3 and h_4. All of these features are in a photometrically interesting region in which the surface brightness profile departs significantly from an r^1/4 law. Features such as these are not generally known in elliptical galaxies owing to a lack of data at comparable resolution. Very similar behavior, however, is seen the kinematics of the edge-on S0 galaxy NGC 3115. We discuss the suggestion that NGC 3379 could be a misclassified S0 galaxy; preliminary results from dynamical modeling indicate that it may be a flattened, weakly

  18. Kinematics of Haro 11: The miniature Antennae

    NASA Astrophysics Data System (ADS)

    Östlin, G.; Marquart, T.; Cumming, R. J.; Fathi, K.; Bergvall, N.; Adamo, A.; Amram, P.; Hayes, M.

    2015-11-01

    Luminous blue compact galaxies are among the most active galaxies in the local Universe in terms of their star formation rate per unit mass. They are rare at the current cosmic epoch, but were more abundant in the past and may be seen as the local analogues of higher red shift Lyman break galaxies. Studies of their kinematics is key to understanding what triggers their unusually active star formation. In this work, we investigate the kinematics of stars and ionised gas in Haro 11, one of the most luminous blue compact galaxies in the local Universe. Previous works have indicated that many of these galaxies may be triggered by galaxy mergers. We have employed Fabry-Perot interferometry, long-slit spectroscopy, and integral field unit (IFU) spectroscopy to explore the kinematics of Haro 11. We target the near-infrared calcium triplet, and use cross-correlation and penalised pixel fitting techniques to derive the stellar velocity field and velocity dispersion. We analyse ionised gas through emission lines from hydrogen, [O iii], and [S iii]. When spectral resolution and signal to noise allows, we investigate the line profile in detail and identify multiple velocity components when present. The spectra reveal a complex velocity field whose components, both stellar and gaseous, we attempt to disentangle. We find that to first order, the velocity field and velocity dispersions derived from stars and ionised gas agree. Hence the complexities reveal real dynamical disturbances providing further evidence for a merger in Haro 11. Through decomposition of emission lines, we find evidence for kinematically distinct components, for instance, a tidal arm. The ionised gas velocity field can be traced to large galactocentric radii, and shows significant velocity dispersion even far out in the halo. If interpreted as virial motions, this indicates that Haro 11 may have a mass of ~1011 M⊙. Haro 11 shows many resemblances with the famous Antennae galaxies both morphologically and

  19. The spinal reflex cannot be perceptually separated from voluntary movements.

    PubMed

    Ghosh, Arko; Haggard, Patrick

    2014-01-01

    Both voluntary and involuntary movements activate sensors in the muscles, skin, tendon and joints. As limb movement can result from a mixture of spinal reflexes and voluntary motor commands, the cortical centres underlying conscious proprioception might either aggregate or separate the sensory inputs generated by voluntary movements from those generated by involuntary movements such as spinal reflexes. We addressed whether healthy volunteers could perceive the contribution of a spinal reflex during movements that combined both reflexive and voluntary contributions. Volunteers reported the reflexive contribution in leg movements that were partly driven by the knee-jerk reflex induced by a patellar tendon tap and partly by voluntary motor control. In one condition, participants were instructed to kick back in response to a tendon tap. The results were compared to reflexes in a resting baseline condition without voluntary movement. In a further condition, participants were instructed to kick forwards after a tap. Volunteers reported the perceived reflex contribution by repositioning the leg to the perceived maximum displacement to which the reflex moved the leg after each tendon tap. In the resting baseline condition, the reflex was accurately perceived. We found a near-unity slope of linear regressions of perceived on actual reflexive displacement. Both the slope value and the quality of regression fit in individual volunteers were significantly reduced when volunteers were instructed to generate voluntary backward kicks as soon as they detected the tap. In the kick forward condition, kinematic analysis showed continuity of reflex and voluntary movements, but the reflex contribution could be estimated from electromyography (EMG) recording on each trial. Again, participants' judgements of reflexes showed a poor relation to reflex EMG, in contrast to the baseline condition. In sum, we show that reflexes can be accurately perceived from afferent information. However

  20. Capturing three-dimensional in vivo lumbar intervertebral joint kinematics using dynamic stereo-X-ray imaging.

    PubMed

    Aiyangar, Ameet K; Zheng, Liying; Tashman, Scott; Anderst, William J; Zhang, Xudong

    2014-01-01

    small compared to the dominant motion in the sagittal plane. The demonstrated success in capturing continuous 3D in vivo lumbar intervertebral kinematics during functional tasks affords the possibility to create a baseline data set for evaluating the lumbar spinal function. The technique can be used to address the gaps in knowledge of lumbar kinematics, to improve the accuracy of the kinematic input into biomechanical models, and to support development of new disk replacement designs more closely replicating the natural lumbar biomechanics. PMID:24149991

  1. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints

    PubMed Central

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-01-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580

  2. Influence of kinematic redundancy on the singularity-free workspace of parallel kinematic machines

    NASA Astrophysics Data System (ADS)

    Kotlarski, Jens; Heimann, Bodo; Ortmaier, Tobias

    2012-06-01

    In this paper the effect of kinematic redundancy in order to reduce the singularity loci of the direct kinematics and to increase the operational, i.e., singularityfree, workspace is demonstrated. The proposed approach consists of additional prismatic actuators allowing one or more base joints to move linearly. As a result, a selective reconfiguration can be performed in order to avoid singular configurations. Exemplarily, kinematically redundant schemes of four structures, the 3 RRR, the 3R PR, the 6U PS, and the 6 RUS, are considered. The relationship between the redundancy and the operational workspace is studied and several analysis examples demonstrate the effectiveness of the proposed concept. Furthermore, the additional benefit of an increasing number of redundant actuators is discussed.

  3. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints.

    PubMed

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-01-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580

  4. Spinal Cord Stimulation and Augmentative Control Strategies for Leg Movement after Spinal Paralysis in Humans.

    PubMed

    Minassian, Karen; Hofstoetter, Ursula S

    2016-04-01

    Severe spinal cord injury is a devastating condition, tearing apart long white matter tracts and causing paralysis and disability of body functions below the lesion. But caudal to most injuries, the majority of neurons forming the distributed propriospinal system, the localized gray matter spinal interneuronal circuitry, and spinal motoneuron populations are spared. Epidural spinal cord stimulation can gain access to this neural circuitry. This review focuses on the capability of the human lumbar spinal cord to generate stereotyped motor output underlying standing and stepping, as well as full weight-bearing standing and rhythmic muscle activation during assisted treadmill stepping in paralyzed individuals in response to spinal cord stimulation. By enhancing the excitability state of the spinal circuitry, the stimulation can have an enabling effect upon otherwise "silent" translesional volitional motor control. Strategies for achieving functional movement in patients with severe injuries based on minimal translesional intentional control, task-specific proprioceptive feedback, and next-generation spinal cord stimulation systems will be reviewed. The role of spinal cord stimulation can go well beyond the immediate generation of motor output. With recently developed training paradigms, it can become a major rehabilitation approach in spinal cord injury for augmenting and steering trans- and sublesional plasticity for lasting therapeutic benefits. PMID:26890324

  5. Rehabilitation of spinal cord injuries

    PubMed Central

    Nas, Kemal; Yazmalar, Levent; Şah, Volkan; Aydın, Abdulkadir; Öneş, Kadriye

    2015-01-01

    Spinal cord injury (SCI) is the injury of the spinal cord from the foramen magnum to the cauda equina which occurs as a result of compulsion, incision or contusion. The most common causes of SCI in the world are traffic accidents, gunshot injuries, knife injuries, falls and sports injuries. There is a strong relationship between functional status and whether the injury is complete or not complete, as well as the level of the injury. The results of SCI bring not only damage to independence and physical function, but also include many complications from the injury. Neurogenic bladder and bowel, urinary tract infections, pressure ulcers, orthostatic hypotension, fractures, deep vein thrombosis, spasticity, autonomic dysreflexia, pulmonary and cardiovascular problems, and depressive disorders are frequent complications after SCI. SCI leads to serious disability in the patient resulting in the loss of work, which brings psychosocial and economic problems. The treatment and rehabilitation period is long, expensive and exhausting in SCI. Whether complete or incomplete, SCI rehabilitation is a long process that requires patience and motivation of the patient and relatives. Early rehabilitation is important to prevent joint contractures and the loss of muscle strength, conservation of bone density, and to ensure normal functioning of the respiratory and digestive system. An interdisciplinary approach is essential in rehabilitation in SCI, as in the other types of rehabilitation. The team is led by a physiatrist and consists of the patients’ family, physiotherapist, occupational therapist, dietician, psychologist, speech therapist, social worker and other consultant specialists as necessary. PMID:25621206

  6. Pain following spinal cord injury.

    PubMed

    Siddall, P J; Loeser, J D

    2001-02-01

    Chronic pain is an important problem following spinal cord injury (SCI) and is a major impediment to effective rehabilitation. The reported prevalence of chronic SCI pain is variable but averages 65% with around one third of these people rating their pain as severe. The mechanisms responsible for the presence of pain are poorly understood. However, evidence from clinical observations and the use of animal models of SCI pain suggests that a number of processes may be important. These include functional and structural plastic changes in the central nervous system following injury, with changes in receptor function and loss of normal inhibition resulting in an increased neuronal excitability. A number of specific types of SCI pain can be distinguished based on descriptors, location and response to treatment. Nociceptive pain can arise from musculoskeletal structures and viscera and neuropathic pain can arise from spinal cord and nerve damage. The role of psychological and environmental factors also needs to be considered. Accurate identification of these pain types will help in selecting appropriate treatment approaches. Current treatments employ a variety of pharmacological, surgical, physical and psychological approaches. However, evidence for many of the treatments in use is still limited. It is hoped that future research will identify effective treatment strategies that accurately target specific mechanisms. PMID:11402361

  7. Arachnoiditis ossificans after spinal surgery.

    PubMed

    Liu, Li-Di; Zhao, Song; Liu, Wan-Guo; Zhang, Shao-Kun

    2015-05-01

    This article presents an unusual case of arachnoiditis ossificans after spinal surgery. A case of arachnoiditis ossificans secondary to lumbar fixation and decompression surgery for the treatment of multilevel lumbar fractures is reported and the relevant literature is reviewed. A 29-year-old man who previously underwent posterior pedicle screw fixation and fusion for multiple lumbar spine fractures reported lower back stiffness and discomfort 23 months postoperatively. A laminectomy was performed at L2 and at L3-L4. At L2, bone fragments from the burst fracture had injured the dural sac and some nerve roots. A posterolateral fusion was performed using allogeneic bone. Postoperatively, there were no signs of fever, infection, or systemic inflammatory responses. Arachnoiditis ossificans of the thecal sac from L1-L5 was diagnosed by magnetic resonance imaging and computed tomography at the 2-year follow-up. His postoperative neurological status progressively improved and he regained motor and sensory functions. Because of neurological improvements, fixation hardware was removed without further decompression. The authors report a case of arachnoiditis ossificans secondary to lumbar fixation and decompression surgery, which involved a large region. Arachnoiditis ossificans is a relatively rare disorder with unclear etiologies and limited treatment options. Spinal surgical intervention of arachnoiditis ossificans should be carefully considered because it may lead to poor outcomes and multiple revision surgeries. PMID:25970374

  8. How realistic are flat-ramp-flat fault kinematic models? Comparing mechanical and kinematic models

    NASA Astrophysics Data System (ADS)

    Cruz, L.; Nevitt, J. M.; Hilley, G. E.; Seixas, G.

    2015-12-01

    Rock within the upper crust appears to deform according to elasto-plastic constitutive rules, but structural geologists often employ kinematic descriptions that prescribe particle motions irrespective of these physical properties. In this contribution, we examine the range of constitutive properties that are approximately implied by kinematic models by comparing predicted deformations between mechanical and kinematic models for identical fault geometric configurations. Specifically, we use the ABAQUS finite-element package to model a fault-bend-fold geometry using an elasto-plastic constitutive rule (the elastic component is linear and the plastic failure occurs according to a Mohr-Coulomb failure criterion). We varied physical properties in the mechanical model (i.e., Young's modulus, Poisson ratio, cohesion yield strength, internal friction angle, sliding friction angle) to determine the impact of each on the observed deformations, which were then compared to predictions of kinematic models parameterized with identical geometries. We found that a limited sub-set of physical properties were required to produce deformations that were similar to those predicted by the kinematic models. Specifically, mechanical models with low cohesion are required to allow the kink at the bottom of the flat-ramp geometry to remain stationary over time. Additionally, deformations produced by steep ramp geometries (30 degrees) are difficult to reconcile between the two types of models, while lower slope gradients better conform to the geometric assumptions. These physical properties may fall within the range of those observed in laboratory experiments, suggesting that particle motions predicted by kinematic models may provide an approximate representation of those produced by a physically consistent model under some circumstances.

  9. Clinical radiology of the spine and spinal cord

    SciTech Connect

    Banna, M.

    1985-01-01

    This book is a source of information about aspects of radiology of the spine and spinal column. It presents coverage of both normal and abnormal conditions. Contents: Spinal fractures and dislocations. Degenerative diseases of the spine. Gross anatomy of the spinal cord and meninges. Intraspinal mass lesions. Spinal dysraphism. Congenital anomalies. Tumors of the vertebral column, and more.

  10. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device used to measure spinal fluid pressure. The device uses a hollow needle, which is inserted into the...

  11. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device used to measure spinal fluid pressure. The device uses a hollow needle, which is inserted into the...

  12. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device used to measure spinal fluid pressure. The device uses a hollow needle, which is inserted into the...

  13. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device used to measure spinal fluid pressure. The device uses a hollow needle, which is inserted into the...

  14. 21 CFR 880.2500 - Spinal fluid manometer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Spinal fluid manometer. 880.2500 Section 880.2500... Devices § 880.2500 Spinal fluid manometer. (a) Identification. A spinal fluid manometer is a device used to measure spinal fluid pressure. The device uses a hollow needle, which is inserted into the...

  15. [Spinal and spinal cord injuries. Therapeutic approach in Gabon].

    PubMed

    Loembe, P M; Bouger, D; Dukuly, L; Ndong-Launay, M

    1991-01-01

    The authors present their experience with 81 cases (66.4%) of acute cervical spine injuries (C.S.I.) and 41 cases (33.6%) of acute thoracolumbar spine injuries (T.L.S.I.) treated by a multidisciplinary approach, at Jeanne Ebori Hospital (Libreville, Gabon) between the years 1981 and 1987. Traffic accidents were the leading cause of injury. The largest group consisted of patients in their third decade. The anatomic localizations were: upper cervical spine: 22 cases (27%); lower cervical spine: 56 (69%); upper thoracic spine: 11 (26.8%); lower thoracic spine or thoracolumbar area: 19 (46.3%); lumbar spine: 7 (17%). There were osteoligamental lesions in 3 cases (3.7%) of C.S.I. and 4 (9.7%) of T.L.S.I. Clinically, 44 patients (54.3%) with C.S.I. and 37 (90.2%) with T.L.S.I. had neurological deficits. Surgical indications depended upon the osseous as well as neurologic lesions. There were five important steps in the treatment of spinal injuries associated with neurological deficit: (1) immobilization, (2) medical stabilization, (3) spinal alignment (skeletal traction), (4) operative decompression if there was proven cord compression, and (5) spinal stabilization. Twenty patients (24.6%) with cervical injuries were treated conservatively (traction, collar, kinesitherapy); 53 (65.4%) underwent a surgical intervention (anterior approach - 21, posterior fusion - 30, combined approach - 2); and in 8 patients (9.8%) refraining from surgery seemed the best alternative. After lengthy multidisciplinary discussion, the authors elected not to operate on tetraplegic patients with respiratory problems that necessitated assisted ventilation, because of its fatal outcome. Of injuries to the thoracolumbar spine, 13 (31.7%) were treated conservatively (bedrest, orthopedic treatment). Twenty-eight patients (68.2%) with unstable thoracic and lumbar fractures associated with neurologic deficit required acute surgical intervention (stabilization with or without decompression of the neural

  16. [A Dumbbell-Type Thoracic Spinal Lipoma: A Case Report].

    PubMed

    Takamiya, Soichiro; Hida, Kazutoshi; Yano, Shunsuke; Sasamori, Toru; Seki, Toshitaka; Saito, Hisatoshi

    2016-06-01

    Spinal lipomas are rare, accounting for less than 1% of all spinal tumors. Most are associated with spinal dysraphism. Spinal lipomas without spinal dysraphism are uncommon;they are typically subpial tumors. Some tumors are located both inside and outside the dura mater (so-called "dumbbell-type"). Herein, we report a patient with a dumbbell-type thoracic spinal lipoma. A man in his 50's complained of progressive gait disturbance, dysesthesia in his left leg, and hyperesthesia in his right leg. His symptoms were worsened by exercise. CT and MRI revealed a thoracic spinal lipoma extending from the spinal cord to the intervertebral foramen at the Th 6-8 level. He underwent partial tumor removal and untethering. Postoperatively he reported gradual symptom abatement. Dumbbell-type spinal lipomas are very rare. Besides partial removal of the tumor, untethering should be considered when symptoms are associated with tethering of the spinal cord. PMID:27270148

  17. Spinal Cord Ring Enhancement in Multiple Sclerosis

    PubMed Central

    Klawiter, Eric C; Benzinger, Tammie; Roy, Abhik; Naismith, Robert T; Parks, Becky J; Cross, Anne H

    2010-01-01

    Objective Describe the clinical and imaging characteristics of spinal cord ring enhancement in multiple sclerosis (MS). Design Clinical case series. Setting Academic referral center. Patients Twenty MS subjects with spinal cord ring enhancement were retrospectively identified from 322 cervical and thoracic spinal cord MRI studies over a 3 year period. Main Outcome Measures Demographics, disability, pattern of enhancement on spinal cord imaging, and concomitant brain magnetic resonance imaging (MRI) were determined. Results Ring enhancement was seen in 20 subjects with spinal cord enhancement, most commonly in the cervical cord. Incomplete or ‘open’ ring enhancement was the dominant pattern in 19 of 20 (95%) subjects. Concurrent ring enhancing brain lesions were present in 40% of subjects. At the time of the MRI, the Expanded Disability Status Scale (EDSS) ranged from 1.0–7.0 (median 3.0). Conclusion Ring enhancement is not an uncommon pattern for MS spinal cord lesions, occurring with a prevalence of 6.2% (20/322). The most common pattern was incomplete ring enhancement in the cervical spinal cord. Recognition of this pattern may improve and expedite the diagnosis of MS and preclude need for invasive diagnostic interventions. PMID:21060017

  18. Magnetic resonance imaging of spinal injury.

    PubMed

    Tracy, P T; Wright, R M; Hanigan, W C

    1989-03-01

    Magnetic resonance imaging (MRI) was performed on 30 patients following spinal injury (SI). Spin-echo sequences and surface coils were used for all patients. Plain radiographs, high-resolution computed tomography (CT), and MRI were compared for the delineation of bone, disc, and ligament injury, measurement of sagittal spinal canal diameter and subluxation, epidural hematoma, and spinal cord structure. Myelography or intrathecal contrast-enhanced CT were not performed on any of these patients. Magnetic resonance imaging accurately delineated intraspinal pathology in two of four patients with acute penetrating SI, and was normal in the other two patients. In 16 patients with acute nonpenetrating SI, MRI was superior to CT for visualizing injuries to discs, ligaments, and the spinal cord, while CT was superior to MRI in characterizing bony injury. Computed tomography and MRI provided similar measurements of subluxation in six of six patients and of sagittal spinal canal diameter in three of four patients. In ten patients with chronic SI, MRI demonstrated post-traumatic cysts, myelomalacia, spinal cord edema, and the presence or absence of spinal cord compression. In patients with acute penetrating SI and chronic SI, MRI provided comprehensive clinical information. In patients with acute nonpenetrating SI, the information obtained by MRI complemented the data given by plain radiographs and CT, allowing clinical decisions to be made without the need of invasive imaging modalities. PMID:2711244

  19. Spinal cord evolution in early Homo.

    PubMed

    Meyer, Marc R; Haeusler, Martin

    2015-11-01

    The discovery at Nariokotome of the Homo erectus skeleton KNM-WT 15000, with a narrow spinal canal, seemed to show that this relatively large-brained hominin retained the primitive spinal cord size of African apes and that brain size expansion preceded postcranial neurological evolution. Here we compare the size and shape of the KNM-WT 15000 spinal canal with modern and fossil taxa including H. erectus from Dmanisi, Homo antecessor, the European middle Pleistocene hominins from Sima de los Huesos, and Pan troglodytes. In terms of shape and absolute and relative size of the spinal canal, we find all of the Dmanisi and most of the vertebrae of KNM-WT 15000 are within the human range of variation except for the C7, T2, and T3 of KNM-WT 15000, which are constricted, suggesting spinal stenosis. While additional fossils might definitively indicate whether H. erectus had evolved a human-like enlarged spinal canal, the evidence from the Dmanisi spinal canal and the unaffected levels of KNM-WT 15000 show that unlike Australopithecus, H. erectus had a spinal canal size and shape equivalent to that of modern humans. Subadult status is unlikely to affect our results, as spinal canal growth is complete in both individuals. We contest the notion that vertebrae yield information about respiratory control or language evolution, but suggest that, like H. antecessor and European middle Pleistocene hominins from Sima de los Huesos, early Homo possessed a postcranial neurological endowment roughly commensurate to modern humans, with implications for neurological, structural, and vascular improvements over Pan and Australopithecus. PMID:26553817

  20. Advance in spinal cord ischemia reperfusion injury: Blood-spinal cord barrier and remote ischemic preconditioning.

    PubMed

    Yu, Qijing; Huang, Jinxiu; Hu, Ji; Zhu, Hongfei

    2016-06-01

    The blood-spinal cord barrier (BSCB) is the physiological and metabolic substance diffusion barrier between blood circulation and spinal cord tissues. This barrier plays a vital role in maintaining the microenvironment stability of the spinal cord. When the spinal cord is subjected to ischemia/reperfusion (I/R) injury, the structure and function of the BSCB is disrupted, further destroying the spinal cord homeostasis and ultimately leading to neurological deficit. Remote ischemic preconditioning (RIPC) is an approach in which interspersed cycles of preconditioning ischemia is followed by reperfusion to tissues/organs to protect the distant target tissues/organs against subsequent lethal ischemic injuries. RIPC is an innovation of the treatment strategies that protect the organ from I/R injury. In this study, we review the morphological structure and function of the BSCB, the injury mechanism of BSCB resulting from spinal cord I/R, and the effect of RIPC on it. PMID:27060223

  1. A Novel Algorithm for the Generation of Distinct Kinematic Chain

    NASA Astrophysics Data System (ADS)

    Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

    2016-07-01

    Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

  2. Metachronous Multiplicity of Spinal Cord Arteriovenous Fistula and Spinal Dural AVF in a Patient with Hereditary Haemorrhagic Telangiectasia

    PubMed Central

    Ling, J.C.M.; Agid, R.; Nakano, S.; Souza, M.P.S.; Reintamm, G.; TerBrugge, K.G.

    2005-01-01

    Summary HHT (Hereditary Haemorrhagic Telangiectasia or Rendu Osler Weber disease) is a known autosomal dominant dysplasia. The first clinical presentation of HHT in a child may be a cerebral or spinal AVM. We present the case of a young boy with HHT who had a previous spinal cord AVF treated by surgical obliteration and then presented with a spinal dural AVF nine months later. This patient had surgical obliteration of a spinal cord perimedullary AVF and subsequently developed a new spinal dural AVF at a different level. The diagnosis was made by spinal MR imaging and spinal angiography PMID:20584440

  3. Kinematical and mechanical aspects of wafer slicing

    NASA Astrophysics Data System (ADS)

    Werner, P. G.

    1982-02-01

    Some recently achieved results concerning the technological fundamentals of slurry sawing are presented. The specific material removal process and the related kinematic and geometric contact conditions between workpiece and saw blade are described. The result of a functional description of the slurry sawing process is presented, expressing the main process criteria, such as infeed per stroke, specific removal rate, specific tool wear, and vertical stroke intensity, in terms of the dominating process parameters, such as stroke length, width of workpiece, stroke frequency, specific cutting force and slurry specification.

  4. Kinematic control of robot with degenerate wrist

    NASA Technical Reports Server (NTRS)

    Barker, L. K.; Moore, M. C.

    1984-01-01

    Kinematic resolved rate equations allow an operator with visual feedback to dynamically control a robot hand. When the robot wrist is degenerate, the computed joint angle rates exceed operational limits, and unwanted hand movements can result. The generalized matrix inverse solution can also produce unwanted responses. A method is introduced to control the robot hand in the region of the degenerate robot wrist. The method uses a coordinated movement of the first and third joints of the robot wrist to locate the second wrist joint axis for movement of the robot hand in the commanded direction. The method does not entail infinite joint angle rates.

  5. Automobile Collisions, Kinematics and Related Injury Patterns

    PubMed Central

    Siegel, A. W.

    1972-01-01

    It has been determined clinically that fatalities and injury severity resulting from automobile collisions have decreased during the last five years for low impact speeds. This reduction is a direct result of the application of biomechanics and occupant kinematics, as well as changes in automobile design. The paper defines terminology used in the field of mechanics and develops examples and illustrations of the physical concepts of acceleration, force strength, magnitude duration, rate of onset and others, as they apply to collision phenomena and injury. The mechanism of injury pattern reduction through the use of restraint systems is illustrated. PMID:5059661

  6. Null-strut calculus. I. Kinematics

    SciTech Connect

    Kheyfets, A.; LaFave, N.J.; Miller, W.A. )

    1990-06-15

    This paper describes the kinematics of null-strut calculus---a 3+1 Regge calculus approach to general relativity. We show how to model the geometry of spacetime with simplicial spacelike three-geometries (TET's) linked to earlier'' and later'' momentumlike lattice surfaces (TET{sup *}) entirely by light rays or null struts.'' These three-layered lattice spacetime geometries are defined and analyzed using combinatorial formulas for the structure of polytopes. The following paper in this series describes how these three-layered spacetime lattices are used to model spacetimes in full conformity with Einstein's theory of gravity.

  7. Kinematics and Fluid Dynamics of Jellyfish Maneuvering

    NASA Astrophysics Data System (ADS)

    Miller, Laura; Hoover, Alex

    2014-11-01

    Jellyfish propel themselves through the water through periodic contractions of their elastic bells. Some jellyfish, such as the moon jellyfish Aurelia aurita and the upside down jellyfish Cassiopea xamachana, can perform turns via asymmetric contractions of the bell. The fluid dynamics of jellyfish forward propulsion and turning is explored here by analyzing the contraction kinematics of several species and using flow visualization to quantify the resulting flow fields. The asymmetric contraction and structure of the jellyfish generates asymmetries in the starting and stopping vortices. This creates a diagonal jet and a net torque acting on the jellyfish. Results are compared to immersed boundary simulations

  8. Quantum simulation of noncausal kinematic transformations.

    PubMed

    Alvarez-Rodriguez, U; Casanova, J; Lamata, L; Solano, E

    2013-08-30

    We propose the implementation of Galileo group symmetry operations or, in general, linear coordinate transformations in a quantum simulator. With an appropriate encoding, unitary gates applied to our quantum system give rise to Galilean boosts or spatial and time parity operations in the simulated dynamics. This framework provides us with a flexible toolbox that enhances the versatility of quantum simulation theory, allowing the direct access to dynamical quantities that would otherwise require full tomography. Furthermore, this method enables the study of noncausal kinematics and phenomena beyond special relativity in a quantum controllable system. PMID:24033011

  9. Failure tolerant operation of kinematically redundant manipulators

    NASA Technical Reports Server (NTRS)

    Lewis, Christopher L.; Maciejewski, Anthony A.

    1994-01-01

    Redundant manipulators may compensate for failed joints with their additional degrees of freedom. In this paper such a manipulator is considered fault tolerant if it can guarantee completion of a task after any one of its joints has failed. This fault tolerance of kinematically redundant manipulators is insured here. Methods to analyze the manipulator's work space find regions inherently suitable for critical tasks because of their high level of failure tolerance. Constraints are then placed on the manipulator's range of motion to guarantee completion of a task.

  10. Kinematic Measurements from YouTube Videos

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.

    2009-04-01

    Video analysis of motion has been in use now for some time.1-3 However, some teachers may not have video equipment or may be looking for innovative ways to engage students with interesting applications at no cost. The recent advent of YouTube offers opportunities for students to measure kinematic properties of real-life events using their computers. This paper provides examples such as measuring the average speed of a winning horse at the Kentucky Derby, plotting speed versus time from watching the speedometer of a high-performance bike, and determining acceleration for circular motion of amusement park rides.

  11. JFKengine: A Jacobian and Forward Kinematics Generator

    SciTech Connect

    Fischer, K.N.

    2003-02-13

    During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific goal of this project is

  12. Nanomedicine for Treating Spinal Cord Injury

    PubMed Central

    Tyler, Jacqueline Y.; Xu, Xiao-Ming; Cheng, Ji-Xin

    2015-01-01

    Spinal cord injury results in significant mortality and morbidity, lifestyle changes, and difficult rehabilitation. Treatment of spinal cord injury is challenging because the spinal cord is both complex to treat acutely and difficult to regenerate. Nanomaterials can be used to provide effective treatments; their unique properties can facilitate drug delivery to the injury site, enact as neuroprotective agents, or provide platforms to stimulate regrowth of damaged tissues. We review recent uses of nanomaterials including nanowires, micelles, nanoparticles, liposomes, and carbon-based nanomaterials for neuroprotection in the acute phase. We also review the design and neural regenerative application of electrospun scaffolds, conduits, and self-assembling peptide scaffolds. PMID:23945984

  13. Post-traumatic recto-spinal fistula.

    PubMed

    Lantsberg, L; Laufer, L; Greenberg, G; Hertzanu, Y

    2000-01-01

    Acquired recto-spinal fistula has been described elsewhere as a rare complication of colorectal malignancy and Crohn's enterocolitis. We treated a young man who developed a recto-spinal fistula as a result of a high fall injury. The patient presented with meningeal signs, sepsis and perianal laceration. Computerized axial tomography revealed air in the supersellar cistern. Gastrografin enema showed that contrast material was leaking from the rectum into the spinal canal. Surgical management included a diverting sigmoid colostomy, sacral bone curettage and wide presacral drainage. To the best of our knowledge, rectospinal fistula of traumatic origin has not been previously reported in the English literature. PMID:10663732

  14. Microsurgical resection of intramedullary spinal cord hemangioblastoma.

    PubMed

    McCormick, Paul C

    2014-09-01

    Spinal cord hemangioblastomas account for about 10% of spinal cord tumors. They usually arise from the dorsolateral pia mater and are characterized by their significant vascularity. The principles and techniques of safe resection are different than those employed for the more commonly occurring intramedullary glial tumors (e.g. ependymoma, astrocytoma) and consist of circumferential detachment of the tumor margin from the surrounding normal pia. This video demonstrates the microsurgical techniques of resection of a thoracic spinal cord hemangioblastoma. The video can be found here: http://youtu.be/yT5KLi4VyAo. PMID:25175571

  15. Microsurgical resection of intramedullary spinal cord ependymoma.

    PubMed

    McCormick, Paul C

    2014-09-01

    Ependymomas are the most commonly occurring intramedullary spinal cord tumor in adults. With few exceptions these tumors are histologically benign, although they exhibit some biologic variability with respect to growth rate. While unencapsulated, spinal ependymomas are non-infiltrative and present a clear margin of demarcation from the surrounding spinal cord that serves as an effective dissection plane. This video demonstrates the technique of microsurgical resection of an intramedullary ependymoma through a posterior midline myelotomy. The video can be found here: http://youtu.be/lcHhymSvSqU. PMID:25175587

  16. Management of infiltrating spinal epidural angiolipoma

    PubMed Central

    Nadi, Mustafa M.; Nadi, Arwa M.; Zabara, Mohammad Y.; Ahmad, Tahani M.

    2015-01-01

    Angiolipomas of the spine are rare benign tumors commonly presenting with compressive myelopathy. The present report describes a case of spinal angiolipoma with thoracic mediastinal extension in a 50-year-old woman. She presented with a long-standing history of mid-back pain with progressive lower extremities weakness. An MRI showed a heterogeneously enhancing mass located in the posterior epidural space of the thoracic spine with mediastinal extension. Histopathological examination demonstrated features consistent with spinal angiolipoma. This report emphasizes the diagnosis and therapeutic management options of infiltrating spinal angiolipomas. PMID:25864069

  17. Pneumocephalus and Pneumorrhachis After Spinal Surgery

    PubMed Central

    Akyüz, Orhan; Gökpınar, Deniz; Aydın, Emsal; Aydın, Sergülen; Duymuş, Mahmut; Çığşar, Gülşen; Özdemir, Murat

    2016-01-01

    Summary Background Pneumocephalus and pneumorrhachis are rare complications of neurosurgery. When a closed system such as the head and spinal area get injuried, it becomes open and the air can come in through that opening. In this case, we present a case of pneumocephalus and pneumorrhachis after spinal fusion surgery. Case Report Herein we present a case of diagnosis and treatment of pneumocephalus and pneumorrhachis after spinal fusion surgery. Conclusions Our patient developed postoperative pneumocephalus and pneumorrhachis as a late complication secondary to an infection. We wanted it to be considered as an important problem. PMID:26893792

  18. Chronic spinal muscular atrophy of facioscapulohumeral type.

    PubMed Central

    Furukawa, T; Toyokura, Y

    1976-01-01

    Chronic spinal muscular atrophy of FSH type affecting a mother and her son and daughter is reported. The relevant literature is reviewed and the relation between this conditon and Kugelberg-Welander (K-W) disease is discussed. Chronic spinal muscular atrophy of FSH type is considered to be a different entity from the eponymous K-W disease. Each type of muscular dystrophy, e.g. limb-girdle, FSH, distal, ocular, or oculopharyngeal type, has its counterpart of nuclear origin. A classification of the chronic spinal muscular atrophies is suggested following the classification of muscular dystrophy. Images PMID:957378

  19. Nanomedicine for treating spinal cord injury

    NASA Astrophysics Data System (ADS)

    Tyler, Jacqueline Y.; Xu, Xiao-Ming; Cheng, Ji-Xin

    2013-09-01

    Spinal cord injury results in significant mortality and morbidity, lifestyle changes, and difficult rehabilitation. Treatment of spinal cord injury is challenging because the spinal cord is both complex to treat acutely and difficult to regenerate. Nanomaterials can be used to provide effective treatments; their unique properties can facilitate drug delivery to the injury site, enact as neuroprotective agents, or provide platforms to stimulate regrowth of damaged tissues. We review recent uses of nanomaterials including nanowires, micelles, nanoparticles, liposomes, and carbon-based nanomaterials for neuroprotection in the acute phase. We also review the design and neural regenerative application of electrospun scaffolds, conduits, and self-assembling peptide scaffolds.

  20. Vestibular lesion-induced developmental plasticity in spinal locomotor networks during Xenopus laevis metamorphosis.

    PubMed

    Beyeler, Anna; Rao, Guillaume; Ladepeche, Laurent; Jacques, André; Simmers, John; Le Ray, Didier

    2013-01-01

    During frog metamorphosis, the vestibular sensory system remains unchanged, while spinal motor networks undergo a massive restructuring associated with the transition from the larval to adult biomechanical system. We investigated in Xenopus laevis the impact of a pre- (tadpole stage) or post-metamorphosis (juvenile stage) unilateral labyrinthectomy (UL) on young adult swimming performance and underlying spinal locomotor circuitry. The acute disruptive effects on locomotion were similar in both tadpoles and juvenile frogs. However, animals that had metamorphosed with a preceding UL expressed restored swimming behavior at the juvenile stage, whereas animals lesioned after metamorphosis never recovered. Whilst kinematic and electrophysiological analyses of the propulsive system showed no significant differences in either juvenile group, a 3D biomechanical simulation suggested that an asymmetry in the dynamic control of posture during swimming could account for the behavioral restoration observed in animals that had been labyrinthectomized before metamorphosis. This hypothesis was subsequently supported by in vivo electromyography during free swimming and in vitro recordings from isolated brainstem/spinal cord preparations. Specifically, animals lesioned prior to metamorphosis at the larval stage exhibited an asymmetrical propulsion/posture coupling as a post-metamorphic young adult. This developmental alteration was accompanied by an ipsilesional decrease in propriospinal coordination that is normally established in strict left-right symmetry during metamorphosis in order to synchronize dorsal trunk muscle contractions with bilateral hindlimb extensions in the swimming adult. Our data thus suggest that a disequilibrium in descending vestibulospinal information during Xenopus metamorphosis leads to an altered assembly of adult spinal locomotor circuitry. This in turn enables an adaptive compensation for the dynamic postural asymmetry induced by the vestibular imbalance

  1. Vestibular Lesion-Induced Developmental Plasticity in Spinal Locomotor Networks during Xenopus laevis Metamorphosis

    PubMed Central

    Beyeler, Anna; Rao, Guillaume; Ladepeche, Laurent; Jacques, André; Simmers, John; Le Ray, Didier

    2013-01-01

    During frog metamorphosis, the vestibular sensory system remains unchanged, while spinal motor networks undergo a massive restructuring associated with the transition from the larval to adult biomechanical system. We investigated in Xenopus laevis the impact of a pre- (tadpole stage) or post-metamorphosis (juvenile stage) unilateral labyrinthectomy (UL) on young adult swimming performance and underlying spinal locomotor circuitry. The acute disruptive effects on locomotion were similar in both tadpoles and juvenile frogs. However, animals that had metamorphosed with a preceding UL expressed restored swimming behavior at the juvenile stage, whereas animals lesioned after metamorphosis never recovered. Whilst kinematic and electrophysiological analyses of the propulsive system showed no significant differences in either juvenile group, a 3D biomechanical simulation suggested that an asymmetry in the dynamic control of posture during swimming could account for the behavioral restoration observed in animals that had been labyrinthectomized before metamorphosis. This hypothesis was subsequently supported by in vivo electromyography during free swimming and in vitro recordings from isolated brainstem/spinal cord preparations. Specifically, animals lesioned prior to metamorphosis at the larval stage exhibited an asymmetrical propulsion/posture coupling as a post-metamorphic young adult. This developmental alteration was accompanied by an ipsilesional decrease in propriospinal coordination that is normally established in strict left-right symmetry during metamorphosis in order to synchronize dorsal trunk muscle contractions with bilateral hindlimb extensions in the swimming adult. Our data thus suggest that a disequilibrium in descending vestibulospinal information during Xenopus metamorphosis leads to an altered assembly of adult spinal locomotor circuitry. This in turn enables an adaptive compensation for the dynamic postural asymmetry induced by the vestibular imbalance

  2. Changes in knee kinematics following total knee arthroplasty.

    PubMed

    Akbari Shandiz, Mohsen; Boulos, Paul; Saevarsson, Stefan Karl; Yoo, Sam; Miller, Stephen; Anglin, Carolyn

    2016-04-01

    Total knee arthroplasty (TKA) changes the knee joint in both intentional and unintentional, known and unknown, ways. Patellofemoral and tibiofemoral kinematics play an important role in postoperative pain, function, satisfaction and revision, yet are largely unknown. Preoperative kinematics, postoperative kinematics or changes in kinematics may help identify causes of poor clinical outcome. Patellofemoral kinematics are challenging to record since the patella is obscured by the metal femoral component in X-ray and moves under the skin. The purpose of this study was to determine the kinematic degrees of freedom having significant changes and to evaluate the variability in individual changes to allow future study of patients with poor clinical outcomes. We prospectively studied the 6 degrees of freedom patellofemoral and tibiofemoral weightbearing kinematics, tibiofemoral contact points and helical axes of rotation of nine subjects before and at least 1 year after total knee arthroplasty using clinically available computed tomography and radiographic imaging systems. Normal kinematics for healthy individuals were identified from the literature. Significant differences existed between pre-TKA and post-TKA kinematics, with the post-TKA kinematics being closer to normal. While on average the pre-total knee arthroplasty knees in this group displayed no pivoting (only translation), individually only five knees displayed this behaviour (of these, two showed lateral pivoting, one showed medial pivoting and one showed central pivoting). There was considerable variability postoperatively as well (five central, two lateral and two medial pivoting). Both preop and postop, flexion behaviour was more hinge-like medially and more rolling laterally. Helical axes were more consistent postop for this group. An inclusive understanding of the pre-TKA and post-TKA kinematics and changes in kinematics due to total knee arthroplasty could improve implant design, patient diagnosis and

  3. Malignancies of the spinal cord.

    PubMed

    Waters, J Dawn; Peran, Encarnacion Maria Navarro; Ciacci, Joseph

    2012-01-01

    The management of intramedullary spinal cord tumors (IMSCT) is primarily concerned with the preservation of existing neurologic function. To this end, clinical scientists are continually seeking tools and techniques to improve the safety and efficacy of tumor resection and control. Further advances in safety and efficacy can be proposed at each phase of management, from pre-operative screening to post-treatment monitoring. Innovations within the areas of molecular biology and genetics, intraoperative imaging and stereotactic radiosurgery offer exciting new options to explore in the management of IMSCT. This section will review the pathophysiology and epidemiology of IMSCT and the state-of-the-art management before delving into the promising new tools and techniques for each phase of management. PMID:23281516

  4. Pain in spinal cord injury.

    PubMed

    Baastrup, Cathrine; Finnerup, Nanna Brix

    2012-01-01

    SUMMARY An important and detrimental effect of spinal cord injury (SCI) is pain, which develops in approximately two-thirds of all SCI patients, while approximately half of SCI patients develop chronic neuropathic pain (NP). Thus far, there is no cure for SCI NP, and oral pharmacological intervention is often inadequate, commonly resulting in a pain reduction of only 20-30%. In this short review, we will present an overview of the important features of SCI pain including taxonomy, epidemiology and classification, as well as a suggested oral pharmacological treatment strategy for SCI NP and the current evidence available from randomized placebo-controlled trials. Considerations and evidence for the nonpharmacological treatment of SCI will be discussed briefly. PMID:24654622

  5. Spinal cord injury in youth.

    PubMed

    Apple, D F; Anson, C A; Hunter, J D; Bell, R B

    1995-02-01

    To identify special characteristics of the pediatric spinal cord-injured (SCI) population, we analyzed a database of 1,770 traumatic SCI patients; 88 (5%) fell into the two pediatric subgroups: 0-12 years (n = 26) and 13-15 years (n = 62) at time of injury. Differences between age groups were identified with regard to demographics, neurologic characteristics, associated injuries and complications, and management. Mode level of bony injury was C2 in preteens, C4 in teens, and C4-C5 in adults. Scoliosis developed far more frequently in children, particularly preteens (23%), than in adults (5%). Violent etiologies, predominantly gunshots, accounted for a disproportionate share of injuries to preteens (19%) and African-Americans (28%), as compared with adults (12%) and Caucasians (7%). This last finding underscores the urgent need to mount a response to the nationwide proliferation of gunshot-related SCI in children and minorities. PMID:7729113

  6. Spinal antinflammatory action of Diclofenac.

    PubMed

    Sandri, Alberto

    2016-06-01

    Diclofenac is a non-steroidal antinflammatory drug (NSAID) that finds indication in the treatment of debilitating pathologies characterized by chronic pain sustained by inflammation, such as in rheumatic disease (rheumatoid arthritis or osteoarthritis) or periarthritis, bursitis, tendonitis, myositis and sciatica. Its properties differentiate it from other NSAIDs. In fact, diclofenac's increased effect on spinal nociception and chronic neuro-inflammatory pain may be referred to: 1) its synergistic effects on peroxisome proliferator-activated receptor-γ (PPAR- γ) activation and prostaglandin synthesis inhibition (COX-2 inhibition); 2) its capacity of suppressing neuronal hyperexcitability through the blockage of neuronal K+ channels in a concentration-dependant manner; and 3) its facility to cross the blood-brain barrier. PMID:27014880

  7. [Application and development of kinematical alighment during total knee arthroplasty].

    PubMed

    Zhang Guo-dong; Yang, Chen; Yang, Guang; Qi, Xin

    2015-12-01

    Kinematical alignment during total knee arthroplasty is an emerging process, and draws more and more attentions from scholars. Knee joint is close to normal joint after TKA through kinematical alighment, which has good clinical results and functional scores, and not increase failure probility. Thus, it may increase joint stress of patella-femur joint, lead to patellar maltracking and increase abrasion. The paper summarized defination and basical principle, operative method, clinical outcomes and deficiency of kinematical alignment during total knee arthroplasty, in order to choose a better way for kinematical alignment during total knee arthroplasty. PMID:26911130

  8. Geometric deviation modeling by kinematic matrix based on Lagrangian coordinate

    NASA Astrophysics Data System (ADS)

    Liu, Weidong; Hu, Yueming; Liu, Yu; Dai, Wanyi

    2015-09-01

    Typical representation of dimension and geometric accuracy is limited to the self-representation of dimension and geometric deviation based on geometry variation thinking, yet the interactivity affection of geometric variation and gesture variation of multi-rigid body is not included. In this paper, a kinematic matrix model based on Lagrangian coordinate is introduced, with the purpose of unified model for geometric variation and gesture variation and their interactive and integrated analysis. Kinematic model with joint, local base and movable base is built. The ideal feature of functional geometry is treated as the base body; the fitting feature of functional geometry is treated as the adjacent movable body; the local base of the kinematic model is fixed onto the ideal geometry, and the movable base of the kinematic model is fixed onto the fitting geometry. Furthermore, the geometric deviation is treated as relative location or rotation variation between the movable base and the local base, and it's expressed by the Lagrangian coordinate. Moreover, kinematic matrix based on Lagrangian coordinate for different types of geometry tolerance zones is constructed, and total freedom for each kinematic model is discussed. Finally, the Lagrangian coordinate library, kinematic matrix library for geometric deviation modeling is illustrated, and an example of block and piston fits is introduced. Dimension and geometric tolerances of the shaft and hole fitting feature are constructed by kinematic matrix and Lagrangian coordinate, and the results indicate that the proposed kinematic matrix is capable and robust in dimension and geometric tolerances modeling.

  9. Kinematics Analysis of an Aided Robot for Needle Insertion

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Gao, Dedong; Wang, Shan; Bai, Huiquan; Zheng, Haojun

    The kinematic relationship between the needle base and the robot's joints is analyzed. The analysis process is based on the aided needle-insertion robot built by our group. The thinking of needle-inserting procedure is confirming the needle base's posture before the needle inserted into tissue. The method of Denavit-Hartenberg (D-H) parameters is used to establish a link robot body-frames with the structural characteristics of the robot. After analysing kinematics, the kinematics equation is presented. The kinematics inverse solutions are obtained with the analytical method and geometry analysis method.

  10. Spinal and Paraspinal Ewing Tumors

    SciTech Connect

    Indelicato, Daniel J.; Keole, Sameer R.; Shahlaee, Amir H.; Morris, Christopher G.; Gibbs, C. Parker; Scarborough, Mark T.; Pincus, David W.; Marcus, Robert B.

    2010-04-15

    Purpose: To perform a review of the 40-year University of Florida experience treating spinal and paraspinal Ewing tumors. Patients and Methods: A total of 27 patients were treated between 1965 and 2007. For local management, 21 patients were treated with radiotherapy (RT) alone and 6 with surgery plus RT. All patients with metastatic disease were treated with RT alone. The risk profiles of each group were otherwise similar. The median age was 17 years, and the most frequent subsite was the sacral spine (n = 9). The median potential follow-up was 16 years. Results: The 5-year actuarial overall survival, cause-specific survival, and local control rate was 62%, 62%, and 90%, respectively. For the nonmetastatic subset (n = 22), the 5-year overall survival, cause-specific survival, and local control rate was 71%, 71%, and 89%, respectively. The local control rate was 84% for patients treated with RT alone vs. 100% for those treated with surgery plus RT. Patients who were >14 years old and those who were treated with intensive therapy demonstrated superior local control. Of 9 patients in our series with Frankel C or greater neurologic deficits at presentation, 7 experienced a full recovery with treatment. Of the 27 patients, 37% experienced Common Toxicity Criteria Grade 3 or greater toxicity, including 2 deaths from sepsis. Conclusion: Aggressive management of spinal and paraspinal Ewing tumors with RT with or without surgery results in high toxicity but excellent local control and neurologic outcomes. Efforts should be focused on identifying disease amenable to combined modality local therapy and improving RT techniques.

  11. APOGEE Kinematics. I. Overview of the Kinematics of the Galactic Bulge as Mapped By APOGEE

    NASA Astrophysics Data System (ADS)

    Ness, M.; Zasowski, G.; Johnson, J. A.; Athanassoula, E.; Majewski, S. R.; García Pérez, A. E.; Bird, J.; Nidever, D.; Schneider, Donald P.; Sobeck, J.; Frinchaboy, P.; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey

    2016-03-01

    We present the stellar kinematics across the Galactic bulge and into the disk at positive longitudes from the SDSS-III APOGEE spectroscopic survey of the Milky Way. APOGEE includes extensive coverage of the stellar populations of the bulge along the midplane and near-plane regions. From these data, we have produced kinematic maps of 10,000 stars across longitudes of 0° < l < 65°, and primarily across latitudes of | b| < 5° in the bulge region. The APOGEE data reveal that the bulge is cylindrically rotating across all latitudes and is kinematically hottest at the very center of the bulge, with the smallest gradients in both kinematic and chemical space inside the innermost region (| l,b| ) < (5°, 5°). The results from APOGEE show good agreement with data from other surveys at higher latitudes and a remarkable similarity to the rotation and dispersion maps of barred galaxies viewed edge-on. The thin bar that is reported to be present in the inner disk within a narrow latitude range of | b| < 2° appears to have a corresponding signature in [{Fe}/{{H}}] and [α /{Fe}]. Stars with [{Fe}/{{H}}] > -0.5 have dispersion and rotation profiles that are similar to that of N-body models of boxy/peanut bulges. There is a smooth kinematic transition from the thin bar and boxy bulge (l,| b| ) < (15°, 12°) out to the disk for stars with [{Fe}/{{H}}] > -1.0, and the chemodynamics across (l, b) suggests that the stars in the inner Galaxy with [{Fe}/{{H}}] > -1.0 originate in the disk.

  12. Nuclear Rings in Galaxies - A Kinematic Perspective

    NASA Technical Reports Server (NTRS)

    Mazzuca, Lisa M.; Swaters, Robert A.; Knapen, Johan H.; Veilleux, Sylvain

    2011-01-01

    We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear rings to show an interconnection between the kinematic properties of the rings and their resonant origin. The nuclear rings have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the rings and those of their host galaxies, indicate the rings are in the same plane as the disc and are circular. From the rotation curves derived, we have estimated the compactness (v(sup 2)/r) up to the turnover radius, which is where the nuclear rings reside. We find that there is evidence of a correlation between compactness and ring width and size. Radially wide rings are less compact, and thus have lower mass concentration. The compactness increases as the ring width decreases. We also find that the nuclear ring size is dependent on the bar strength, with weaker bars allowing rings of any size to form.

  13. Kinematics and Aerodynamics of Backward Flying Dragonflies

    NASA Astrophysics Data System (ADS)

    Bode-Oke, Ayodeji; Zeyghami, Samane; Dong, Haibo

    2015-11-01

    Highly maneuverable insects such as dragonflies have a wide range of flight capabilities; precise hovering, fast body reorientations, sideways flight and backward takeoff are only a few to mention. In this research, we closely examined the kinematics as well as aerodynamics of backward takeoff in dragonflies and compared them to those of forward takeoff. High speed videography and accurate 3D surface reconstruction techniques were employed to extract details of the wing and body motions as well as deformations during both flight modes. While the velocities of both forward and backward flights were similar, the body orientation as well as the wing kinematics showed large differences. Our results indicate that by tilting the stroke plane angle of the wings as well as changing the orientation of the body relative to the flight path, dragonflies control the direction of the flight like a helicopter. In addition, our detailed analysis of the flow in these flights shows important differences in the wake capture phenomena among these flight modes. This work is supported by NSF CBET-1313217.

  14. Kinematically consistent models of viscoelastic stress evolution

    NASA Astrophysics Data System (ADS)

    DeVries, Phoebe M. R.; Meade, Brendan J.

    2016-05-01

    Following large earthquakes, coseismic stresses at the base of the seismogenic zone may induce rapid viscoelastic deformation in the lower crust and upper mantle. As stresses diffuse away from the primary slip surface in these lower layers, the magnitudes of stress at distant locations (>1 fault length away) may slowly increase. This stress relaxation process has been used to explain delayed earthquake triggering sequences like the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes in California. However, a conceptual difficulty associated with these models is that the magnitudes of stresses asymptote to constant values over long time scales. This effect introduces persistent perturbations to the total stress field over many earthquake cycles. Here we present a kinematically consistent viscoelastic stress transfer model where the total perturbation to the stress field at the end of the earthquake cycle is zero everywhere. With kinematically consistent models, hypotheses about the potential likelihood of viscoelastically triggered earthquakes may be based on the timing of stress maxima, rather than on any arbitrary or empirically constrained stress thresholds. Based on these models, we infer that earthquakes triggered by viscoelastic earthquake cycle effects may be most likely to occur during the first 50% of the earthquake cycle regardless of the assumed long-term and transient viscosities.

  15. Gait kinematic analysis evaluates hindlimb revascularization.

    PubMed

    Ríos, Amelia; Delgado, Alexandra; Escalante, Bruno; Santana, Jesús

    2011-01-01

    Peripheral arterial occlusive disease is described as vascular disorders associated with ischemia and may be the result of an obstructive vascular process or a lost revascularization response. We have shown that gait locomotion analysis by video filming represents an integrative model for the evaluation of mechanisms involved in the process of ischemia-induced revascularization. However, analysis by this method can be subjective and perception errors may be occurring. We present the optimization of a quantifiable, noninvasive, reproducible method that analyzes ankle kinematics in rats using a two-dimensional digital video system. Gait dynamics were filmed in hindlimb ischemic rats with a high speed digital video camera. Images were collected and analyzed at 125 frames per second. An algorithm using interactive data language (IDL) was devised to assess different parameters. In ischemic rats, stride time and knee joint angle remained altered 10 days post-surgery compared with sham animals. Gait kinematics were outlined in a highly reliable way by this computational analysis and corroborated the notion of hindlimb movement recovery associated with the revascularization process. PMID:22423574

  16. Friction Stir Welding at MSFC: Kinematics

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.

    2001-01-01

    In 1991 The Welding Institute of the United Kingdom patented the Friction Stir Welding (FSW) process. In FSW a rotating pin-tool is inserted into a weld seam and literally stirs the faying surfaces together as it moves up the seam. By April 2000 the American Welding Society International Welding and Fabricating Exposition featured several exhibits of commercial FSW processes and the 81st Annual Convention devoted a technical session to the process. The FSW process is of interest to Marshall Space Flight Center (MSFC) as a means of avoiding hot-cracking problems presented by the 2195 aluminum-lithium alloy, which is the primary constituent of the Lightweight Space Shuttle External Tank. The process has been under development at MSFC for External Tank applications since the early 1990's. Early development of the FSW process proceeded by cut-and-try empirical methods. A substantial and complex body of data resulted. A theoretical model was wanted to deal with the complexity and reduce the data to concepts serviceable for process diagnostics, optimization, parameter selection, etc. A first step in understanding the FSW process is to determine the kinematics, i.e., the flow field in the metal in the vicinity of the pin-tool. Given the kinematics, the dynamics, i.e., the forces, can be targeted. Given a completed model of the FSW process, attempts at rational design of tools and selection of process parameters can be made.

  17. Flapping flight: effect of asymmetric kinematics

    NASA Astrophysics Data System (ADS)

    Pande, Nakul; Krithivasan, Siddharth; K. R., Sreenivas

    2014-11-01

    Flapping flight has received considerable attention in the past with its relevance in the design of micro-air vehicles. In this regard, asymmetric flapping of wings offers simple kinematics. Nevertheless, it leads to symmetry-breaking in the flow field and generation of sustained lift. It has been observed previously with flow visualization experiments and Discrete Vortex Method (DVM) simulations that if the down-stroke time period is lesser than the up-stroke time, there is a net downward momentum imparted to the fluid. This is seen as a switching the flow field from a four-jet (symmetric) to a two-jet (asymmetric) configuration when the stroke-time ratio is progressively varied. This symmetry breaking has been studied experimentally using Particle Image Velocimetry (PIV) across a range of Reynolds Numbers and asymmetry ratios. Results are also corroborated with results from 3-D numerical simulations. Study helps in shedding light on the effectiveness of asymmetric kinematics as a lift generation mechanism.

  18. Kinematics of signature writing in healthy aging.

    PubMed

    Caligiuri, Michael P; Kim, Chi; Landy, Kelly M

    2014-07-01

    Forensic document examiners (FDE) called upon to distinguish a genuine from a forged signature of an elderly person are often required to consider the question of age-related deterioration and whether the available exemplars reliably capture the natural effects of aging of the original writer. An understanding of the statistical relationship between advanced age and handwriting movements can reduce the uncertainty that may exist in an examiner's approach to questioned signatures formed by elderly writers. The primary purpose of this study was to systematically examine age-related changes in signature kinematics in healthy writers. Forty-two healthy subjects between the ages of 60-91 years participated in this study. Signatures were recorded using a digitizing tablet, and commercial software was used to examine the temporal and spatial stroke kinematics and pen pressure. Results indicated that vertical stroke duration and dysfluency increased with age, whereas vertical stroke amplitude and velocity decreased with age. Pen pressure decreased with age. We found that a linear model characterized the best-fit relationship between advanced age and handwriting movement parameters for signature formation. Male writers exhibited stronger age effects than female writers, especially for pen pressure and stroke dysfluency. The present study contributes to an understanding of how advanced age alters signature formation in otherwise healthy adults. PMID:24673648

  19. THE KINEMATICS OF PRIMATE MIDFOOT FLEXIBILITY

    PubMed Central

    Greiner, Thomas M.; Ball, Kevin A.

    2015-01-01

    This study describes a unique assessment of primate intrinsic foot joint kinematics based upon bone pin rigid cluster tracking. It challenges the assumption that human evolution resulted in a reduction of midfoot flexibility, which has been identified in other primates as the “midtarsal break.” Rigid cluster pins were inserted into the foot bones of human, chimpanzee, baboon and macaque cadavers. The positions of these bone pins were monitored during a plantarflexion-dorsiflexion movement cycle. Analysis resolved flexion-extension movement patterns and the associated orientation of rotational axes for the talonavicular, calcaneocuboid and lateral cubometatarsal joints. Results show that midfoot flexibility occurs primarily at the talonavicular and cubometatarsal joints. The rotational magnitudes are roughly similar between humans and chimps. There is also a similarity among evaluated primates in the observed rotations of the lateral cubometatarsal joint, but there was much greater rotation observed for the talonavicular joint, which may serve to differentiate monkeys from the hominines. It appears that the capability for a midtarsal break is present within the human foot. A consideration of the joint axes shows that the medial and lateral joints have opposing orientations, which has been associated with a rigid locking mechanism in the human foot. However, the potential for this same mechanism also appears in the chimpanzee foot. These findings demonstrate a functional similarity within the midfoot of the hominines. Therefore, the kinematic capabilities and restrictions for the skeletal linkages of the human foot may not be as unique as has been previously suggested. PMID:25234343

  20. Bayesian Kinematic Finite Fault Source Models (Invited)

    NASA Astrophysics Data System (ADS)

    Minson, S. E.; Simons, M.; Beck, J. L.

    2010-12-01

    Finite fault earthquake source models are inherently under-determined: there is no unique solution to the inverse problem of determining the rupture history at depth as a function of time and space when our data are only limited observations at the Earth's surface. Traditional inverse techniques rely on model constraints and regularization to generate one model from the possibly broad space of all possible solutions. However, Bayesian methods allow us to determine the ensemble of all possible source models which are consistent with the data and our a priori assumptions about the physics of the earthquake source. Until now, Bayesian techniques have been of limited utility because they are computationally intractable for problems with as many free parameters as kinematic finite fault models. We have developed a methodology called Cascading Adaptive Tempered Metropolis In Parallel (CATMIP) which allows us to sample very high-dimensional problems in a parallel computing framework. The CATMIP algorithm combines elements of simulated annealing and genetic algorithms with the Metropolis algorithm to dynamically optimize the algorithm's efficiency as it runs. We will present synthetic performance tests of finite fault models made with this methodology as well as a kinematic source model for the 2007 Mw 7.7 Tocopilla, Chile earthquake. This earthquake was well recorded by multiple ascending and descending interferograms and a network of high-rate GPS stations whose records can be used as near-field seismograms.

  1. The Kinematics of Turbulent Boundary Layer Structure

    NASA Technical Reports Server (NTRS)

    Robinson, Stephen Kern

    1991-01-01

    The long history of research into the internal structure of turbulent boundary layers has not provided a unified picture of the physics responsible for turbulence production and dissipation. The goals of the present research are to: (1) define the current state of boundary layer structure knowledge; and (2) utilize direct numerical simulation results to help close the unresolved issues identified in part A and to unify the fragmented knowledge of various coherent motions into a consistent kinematic model of boundary layer structure. The results of the current study show that all classes of coherent motion in the low Reynolds number turbulent boundary layer may be related to vortical structures, but that no single form of vortex is representative of the wide variety of vortical structures observed. In particular, ejection and sweep motions, as well as entrainment from the free-streem are shown to have strong spatial and temporal relationships with vortical structures. Disturbances of vortex size, location, and intensity show that quasi-streamwise vortices dominate the buffer region, while transverse vortices and vortical arches dominate the wake region. Both types of vortical structure are common in the log region. The interrelationships between the various structures and the population distributions of vortices are combined into a conceptual kinematic model for the boundary layer. Aspects of vortical structure dynamics are also postulated, based on time-sequence animations of the numerically simulated flow.

  2. Testing Iberia Kinematics at Jurassic-Cretaceous

    NASA Astrophysics Data System (ADS)

    Neres, Marta; Miranda, J. Miguel; Font, Eric

    2013-04-01

    Paleogeographic reconstructions of Iberia at Mesozoic are still a matter of debate. A major problem resides in the incompatibility existing between kinematic models and paleomagnetic data older than 120 Ma. Here, we investigate the origin of this misfit by finding and testing euler poles that fit Iberian mean paleomagnetic poles (123, 130 and 151 Ma) with global APWP. At 123 Ma 130 Ma, no geologically plausible solutions were found, questioning the validity of corresponding paleomagnetic data. Contrarily, for 151 Ma mean pole, coherent solutions were simulated, suggesting respective paleomagnetic data as potentially reliable. Based on these results, we propose a new magnetic reconstruction for Iberia and surrounding plates at ~150 Ma, to which corresponds the IB-NAM euler pole -18.08 / 67.54 / -57.72 (long / lat / angle). This is the first pre-drift reconstruction for Iberia to be compatible with paleomagnetic data. A complete and coherent model for the Jurassic-Cretaceous kinematic evolution of Iberia is still dependent on more and better paleomagnetic poles and on a reevaluation of magnetic anomalies, for which several problems remain unsolved.

  3. Effects of asymmetric sitting on spinal balance

    PubMed Central

    Woo, Hee Soon; Oh, Jong Chi; Won, Sung Yoon

    2016-01-01

    [Purpose] To investigate the effects of two common asymmetric sitting positions on spinal balance. [Subjects and Methods] Thirty-seven healthy subjects in their twenties were enrolled and randomly divided into two groups. Asymmetric positions of resting the chin on a hand and crossing the legs were performed by each group for 1 hour. After 1 hour, the subjects lay in the supine position again and spinal imbalance was measured using a device. [Results] After 1 hour of resting with the chin on a hand, sagittal imbalance, coronal imbalance, pelvic obliquity and lordosis angle presented spinal imbalance worsening of 1 hour of crossing legs, sagittal imbalance, pelvic torsion showed in mainly learned spinal imbalance living. [Conclusion] Good posture could be an innate ability, however it through habits. So this study is meaningful from the perspective of the importance of good posture. PMID:27065291

  4. Simulation and resident education in spinal neurosurgery

    PubMed Central

    Bohm, Parker E.; Arnold, Paul M.

    2015-01-01

    Background: A host of factors have contributed to the increasing use of simulation in neurosurgical resident education. Although the number of simulation-related publications has increased exponentially over the past two decades, no studies have specifically examined the role of simulation in resident education in spinal neurosurgery. Methods: We performed a structured search of several databases to identify articles detailing the use of simulation in spinal neurosurgery education in an attempt to catalogue potential applications for its use. Results: A brief history of simulation in medicine is given, followed by current trends of spinal simulation utilization in residency programs. General themes from the literature are identified that are integral for implementing simulation into neurosurgical residency curriculum. Finally, various applications are reported. Conclusion: The use of simulation in spinal neurosurgery education is not as ubiquitous in comparison to other neurosurgical subspecialties, but many promising methods of simulation are available for augmenting resident education. PMID:25745588

  5. Brain and Spinal Cord Tumors in Adults

    MedlinePlus

    ... saved articles window. My Saved Articles » My ACS » Brain and Spinal Cord Tumors in Adults Download Printable ... the topics below to get started. What Is Brain/CNS Tumors In Adults? What are adult brain ...

  6. Spinal Cord Injury: Hope through Research

    MedlinePlus

    ... chronic pain in people with spinal cord injury. Robotic-assisted therapy Most recovery following SCI takes place ... the safety and efficacy of a type of robotic therapy device known as the AMES device. The ...

  7. Brain and Spinal Tumors: Hope through Research

    MedlinePlus

    ... of the CNS. Some tools used in the operating room include a surgical microscope, the endoscope (a ... cells, which support other brain function. central nervous system (CNS)—the brain and spinal cord. cerebrospinal fluid ( ...

  8. Advanced noninvasive imaging of spinal vascular malformations

    PubMed Central

    Eddleman, Christopher S.; Jeong, Hyun; Cashen, Ty A.; Walker, Matthew; Bendok, Bernard R.; Batjer, H. Hunt; Carroll, Timothy J.

    2010-01-01

    Spinal vascular malformations (SVMs) are an uncommon, heterogeneous group of vascular anomalies that can render devastating neurological consequences if they are not diagnosed and treated in a timely fashion. Imaging SVMs has always presented a formidable challenge because their clinical and imaging presentations resemble those of neoplasms, demyelination diseases, and infection. Advancements in noninvasive imaging modalities (MR and CT angiography) have increased during the last decade and have improved the ability to accurately diagnose spinal vascular anomalies. In addition, intraoperative imaging techniques have been developed that aid in the intraoperative assessment before, during, and after resection of these lesions with minimal and/or optimal use of spinal digital subtraction angiography. In this report, the authors review recent advancements in the imaging of SVMs that will likely lead to more timely diagnoses and treatment while reducing procedural risk exposure to the patients who harbor these uncommon spinal lesions. PMID:19119895

  9. Congenital narrowing of the cervical spinal canal.

    PubMed Central

    Kessler, J T

    1975-01-01

    The clinical and laboratory findings in six patients with congenital narrowing of the cervical spinal canal and neurological symptoms are described. A variable age of onset and an entirely male occurrence were found. Signs and symptoms of spinal cord dysfunction predominated in all but one patient. Symptoms were produced in five patients by increased physical activity alone. Congenital narrowing of the cervical spinal canal may result in cord compression without a history of injury and occasionally without evidence of significant bony degenerative changes. The clinical features may be distinguishable from those found in cervical spondylosis without congenital narrowing. Intermittent claudication of the cervical spinal cord appears to be an important feature of this syndrome. Surgery improved four out of five people. PMID:1219087

  10. Investigation of spinal pathology in notalgia paresthetica.

    PubMed

    Savk, Oner; Savk, Ekin

    2005-06-01

    A possible association of spinal pathology with notalgia paresthetica (NP) was investigated through clinical and radiographic evaluation. Forty-three NP patients underwent dermatologic and orthopedic examination accompanied by radiography of the spine. Sixty-one lesions in 43 patients were evaluated. In 34 patients, various vertebral pathologies were observed radiographically by a blinded investigator, and in 28 of these cases these changes were most prominent in the vertebrae which corresponded to a lesional dermatome. Thirty-seven lesions were accompanied by spinal changes decided to be relevant (60.7%). The striking correlation of NP localization with spinal pathology suggests that spinal nerve impingement may contribute to the pathogenesis of this entity. PMID:15928634

  11. Spinal cord protection in aortic endovascular surgery.

    PubMed

    Scott, D A; Denton, M J

    2016-09-01

    A persistent neurological deficit, such as paraplegia or paraparesis, secondary to spinal cord injury remains one of the most feared complications of surgery on the descending thoracic or abdominal aorta. This is despite sophisticated advances in imaging and the use of less invasive endovascular procedures. Extensive fenestrated endovascular aortic graft prostheses still carry a risk of spinal cord injury of up to 10%; thus, this risk should be identified and strategies implemented to protect the spinal cord and maintain perfusion. The patients at highest risk are those undergoing extensive thoracic aortic stenting including thoracic, abdominal, and pelvic vessels. Although many techniques are available, lumbar cerebrospinal fluid drainage remains the most frequent intervention, along with maintenance of perfusion pressure and possibly staged procedures to allow collateral vessel stabilization. Many questions remain regarding other technical aspects, spinal cord monitoring and cooling, pharmacological protection, and the optimal duration of interventions into the postoperative period. PMID:27566805

  12. Staging Childhood Brain and Spinal Cord Tumors

    MedlinePlus

    ... before the cancer is diagnosed and continue for months or years. Childhood brain and spinal cord tumors ... after treatment. Some cancer treatments cause side effects months or years after treatment has ended. These are ...

  13. Segmentation of the human spinal cord.

    PubMed

    De Leener, Benjamin; Taso, Manuel; Cohen-Adad, Julien; Callot, Virginie

    2016-04-01

    Segmenting the spinal cord contour is a necessary step for quantifying spinal cord atrophy in various diseases. Delineating gray matter (GM) and white matter (WM) is also useful for quantifying GM atrophy or for extracting multiparametric MRI metrics into specific WM tracts. Spinal cord segmentation in clinical research is not as developed as brain segmentation, however with the substantial improvement of MR sequences adapted to spinal cord MR investigations, the field of spinal cord MR segmentation has advanced greatly within the last decade. Segmentation techniques with variable accuracy and degree of complexity have been developed and reported in the literature. In this paper, we review some of the existing methods for cord and WM/GM segmentation, including intensity-based, surface-based, and image-based methods. We also provide recommendations for validating spinal cord segmentation techniques, as it is important to understand the intrinsic characteristics of the methods and to evaluate their performance and limitations. Lastly, we illustrate some applications in the healthy and pathological spinal cord. One conclusion of this review is that robust and automatic segmentation is clinically relevant, as it would allow for longitudinal and group studies free from user bias as well as reproducible multicentric studies in large populations, thereby helping to further our understanding of the spinal cord pathophysiology and to develop new criteria for early detection of subclinical evolution for prognosis prediction and for patient management. Another conclusion is that at the present time, no single method adequately segments the cord and its substructure in all the cases encountered (abnormal intensities, loss of contrast, deformation of the cord, etc.). A combination of different approaches is thus advised for future developments, along with the introduction of probabilistic shape models. Maturation of standardized frameworks, multiplatform availability, inclusion

  14. Symptomatic spinal cord metastasis from cerebral oligodendroglioma.

    PubMed

    Elefante, A; Peca, C; Del Basso De Caro, M L; Russo, C; Formicola, F; Mariniello, G; Brunetti, A; Maiuri, F

    2012-06-01

    Spinal subarachnoid spread is not uncommon in brain oligodendrogliomas; on the other hand, symptomatic involvement of the spinal cord and cauda is very rare, with only 16 reported cases. We report the case of a 41-year-old man who underwent resection of a low-grade frontal oligodendroglioma 4 years previously. He was again observed because of bilateral sciatic pain followed by left leg paresis. A spine MRI showed an intramedullary T12-L1 tumor with root enhancement. At operation, an intramedullary anaplastic oligodendroglioma with left exophytic component was found and partially resected. Two weeks later, a large left frontoparietal anaplastic oligodendroglioma was diagnosed and completely resected. The patient was neurologically stable for 8 months and died 1 year after the spinal surgery because of diffuse brain and spinal leptomeningeal spread. The review of the reported cases shows that spinal symptomatic metastases can occur in both low-grade and anaplastic oligodendrogliomas, even many years after surgery of the primary tumor; however, they exceptionally occur as first clinical manifestation or as anaplastic progression. The spinal seeding represents a negative event leading to a short survival. PMID:21927882

  15. Perturbed cholesterol homeostasis in aging spinal cord.

    PubMed

    Parkinson, Gemma M; Dayas, Christopher V; Smith, Doug W

    2016-09-01

    The spinal cord is vital for the processing of sensorimotor information and for its propagation to and from both the brain and the periphery. Spinal cord function is affected by aging, however, the mechanisms involved are not well-understood. To characterize molecular mechanisms of spinal cord aging, microarray analyses of gene expression were performed on cervical spinal cords of aging rats. Of the metabolic and signaling pathways affected, cholesterol-associated pathways were the most comprehensively altered, including significant downregulation of cholesterol synthesis-related genes and upregulation of cholesterol transport and metabolism genes. Paradoxically, a significant increase in total cholesterol content was observed-likely associated with cholesterol ester accumulation. To investigate potential mechanisms for the perturbed cholesterol homeostasis, we quantified the expression of myelin and neuroinflammation-associated genes and proteins. Although there was minimal change in myelin-related expression, there was an increase in phagocytic microglial and astrogliosis markers, particularly in the white matter. Together, these results suggest that perturbed cholesterol homeostasis, possibly as a result of increased inflammatory activation in spinal cord white matter, may contribute to impaired spinal cord function with aging. PMID:27459933

  16. Spinal infections in children: A review.

    PubMed

    Tyagi, Rahul

    2016-12-01

    Spinal infections are uncommon but significant causes of morbidity and hospitalization in the paediatric population. These infections encompass a broad range of conditions, from discitis to osteomyelitis and spinal epidural and intramedullary abscesses. Paediatric spinal infections can be caused by a range of bacterial, viral, fungal and parasitic agents. Ultrastructural differences of the vertebrae and associated structures result in distinct mechanisms of pathogenesis of spinal infections in children compared to adults. The non-specific nature of symptoms produced by them can cause considerable diagnostic delays. Magnetic Resonance (MR) imaging can facilitate early identification of the disease, and distinguish it from other spinal pathologies. The association of antimicrobial resistant bacterial strains from some of the cases appears worrisome; as is the increasing incidence of Kingella kingae infections causing spinal infections. Rest and immobilization are the general treatment, and prompt initiation of antimicrobial therapy is warranted to ensure optimal clinical outcome. Most patients generally have a good prognosis; however, early identification and prompt initiation of antimicrobial therapy is essential to achieve the best therapeutic response. PMID:27408498

  17. Deployable antenna kinematics using tensegrity structure design

    NASA Astrophysics Data System (ADS)

    Knight, Byron Franklin

    With vast changes in spacecraft development over the last decade, a new, cheaper approach was needed for deployable kinematic systems such as parabolic antenna reflectors. Historically, these mesh-surface reflectors have resembled folded umbrellas, with incremental redesigns utilized to save packaging size. These systems are typically over-constrained designs, the assumption being that high reliability necessary for space operations requires this level of conservatism. But with the rapid commercialization of space, smaller launch platforms and satellite buses have demanded much higher efficiency from all space equipment than can be achieved through this incremental approach. This work applies an approach called tensegrity to deployable antenna development. Kenneth Snelson, a student of R. Buckminster Fuller, invented Tensegrity structures in 1948. Such structures use a minimum number of compression members (struts); stability is maintain using tension members (ties). The novelty introduced in this work is that the ties are elastic, allowing the struts to extend or contract, and in this way changing the surface of the antenna. Previously, the University of Florida developed an approach to quantify the stability and motion of parallel manipulators. This approach was applied to deployable, tensegrity, antenna structures. Based on the kinematic analyses for the 3-3 (octahedron) and 4-4 (square anti-prism) structures, the 6-6 (hexagonal anti-prism) analysis was completed which establishes usable structural parameters. The primary objective for this work was to prove the stability of this class of deployable structures, and their potential application to space structures. The secondary objective is to define special motions for tensegrity antennas, to meet the subsystem design requirements, such as addressing multiple antenna-feed locations. This work combines the historical experiences of the artist (Snelson), the mathematician (Ball), and the space systems engineer

  18. Kinematic analysis of reaching in the cat.

    PubMed

    Martin, J H; Cooper, S E; Ghez, C

    1995-01-01

    The present study examines the kinematic features of forelimb movements made by cats reaching for food in horizontal target wells located at different heights and distances. Wrist paths consisted of two relatively straight segments joined at a "via-point" in front of the aperture of the food well. In the initial lift phase, the paw was raised to the via-point in front of the target. In the second, or thrust phase, the paw was directed forward into the food well. During the lift, the paw was moved toward the target primarily by elbow flexion, accompanied by a sequence of biphasic shoulder and wrist movements. Thrust was accomplished primarily by shoulder flexion while the wrist and the paw were maintained at near-constant angles. The animals varied the height of the reach primarily by varying elbow flexion with proportional changes in elbow angular velocity and angular acceleration and with corresponding variations in wrist speed. Thus, cats reached for targets at different heights by scaling a common kinematic profile. Over a relatively large range of target heights, animals maintained movement duration constant, according to a simple "pulse-height" control strategy (isochronous scaling). For reaches to a given target height, animals compensated for variability in peak acceleration by variations in movement time. We examined the coordination between the shoulder and the wrist with the elbow. Early during the lift, peak shoulder extensor and peak elbow flexor accelerations were synchronized. Late during the lift phase, wrist extensor acceleration was found to occur during the period of elbow flexor deceleration. We hypothesize that these linkages could, in part, be due to passive mechanical interactions. To determine how the angular trajectories of the different joints were organized in relation to target location, we plotted joint kinematic changes directly on the wrist and MCP joint paths. These plots revealed that for all target heights and movement speeds, wrist

  19. [Spinal and extra-spinal tumors mimicking discal herniation].

    PubMed

    Tamir, E; Mirovsky, Y; Robinson, D; Halperin, N

    1999-12-15

    Low back pain radiating to a limb is usually caused by lumbar disc herniation. Tumors of the spinal cord or near the sciatic or femoral plexus can cause neural compression and clinical signs similar to those of disc herniation. Such tumors are usually misdiagnosed as discal herniation and appropriate treatment is delayed. We present 4 men who had tumors causing low back pain radiating to the leg: a 70-year-old with metastatic squamous cell carcinoma of the lung, a 20-year-old with aneurysmal bone cyst of the vertebral column, a 52-year-old with retroperitoneal sarcoma and a 32-year-old who also had retroperitoneal sarcoma. Diagnosis and treatment were delayed because the clinical symptoms were ascribed to lumbar disc herniation. The latter 2 patients had CT-scans showing lumbar disc herniation, but similar findings are common among asymptomatic individuals. The differential diagnosis of low back pain radiating to the leg should include tumor when there is a history of cancer, pain not relieved by conservative treatment nor by lying down, pain is increased at night, pain accompanied by weight loss, and when physical examination demonstrates injury to more than 1 nerve root. In these circumstances work-up should include EMG, radioisotope scan and CT of the pelvis. PMID:10959387

  20. Inducing hindlimb locomotor recovery in adult rat after complete thoracic spinal cord section using repeated treadmill training with perineal stimulation only

    PubMed Central

    Alluin, Olivier; Delivet-Mongrain, Hugo

    2015-01-01

    Although a complete thoracic spinal cord section in various mammals induces paralysis of voluntary movements, the spinal lumbosacral circuitry below the lesion retains its ability to generate hindlimb locomotion. This important capacity may contribute to the overall locomotor recovery after partial spinal cord injury (SCI). In rats, it is usually triggered by pharmacological and/or electrical stimulation of the cord while a robot sustains the animals in an upright posture. In the present study we daily trained a group of adult spinal (T7) rats to walk with the hindlimbs for 10 wk (10 min/day for 5 days/wk), using only perineal stimulation. Kinematic analysis and terminal electromyographic recordings revealed a strong effect of training on the reexpression of hindlimb locomotion. Indeed, trained animals gradually improved their locomotion while untrained animals worsened throughout the post-SCI period. Kinematic parameters such as averaged and instant swing phase velocity, step cycle variability, foot drag duration, off period duration, and relationship between the swing features returned to normal values only in trained animals. The present results clearly demonstrate that treadmill training alone, in a normal horizontal posture, elicited by noninvasive perineal stimulation is sufficient to induce a persistent hindlimb locomotor recovery without the need for more complex strategies. This provides a baseline level that should be clearly surpassed if additional locomotor-enabling procedures are added. Moreover, it has a clinical value since intrinsic spinal reorganization induced by training should contribute to improve locomotor recovery together with afferent feedback and supraspinal modifications in patients with incomplete SCI. PMID:26203108

  1. Inducing hindlimb locomotor recovery in adult rat after complete thoracic spinal cord section using repeated treadmill training with perineal stimulation only.

    PubMed

    Alluin, Olivier; Delivet-Mongrain, Hugo; Rossignol, Serge

    2015-09-01

    Although a complete thoracic spinal cord section in various mammals induces paralysis of voluntary movements, the spinal lumbosacral circuitry below the lesion retains its ability to generate hindlimb locomotion. This important capacity may contribute to the overall locomotor recovery after partial spinal cord injury (SCI). In rats, it is usually triggered by pharmacological and/or electrical stimulation of the cord while a robot sustains the animals in an upright posture. In the present study we daily trained a group of adult spinal (T7) rats to walk with the hindlimbs for 10 wk (10 min/day for 5 days/wk), using only perineal stimulation. Kinematic analysis and terminal electromyographic recordings revealed a strong effect of training on the reexpression of hindlimb locomotion. Indeed, trained animals gradually improved their locomotion while untrained animals worsened throughout the post-SCI period. Kinematic parameters such as averaged and instant swing phase velocity, step cycle variability, foot drag duration, off period duration, and relationship between the swing features returned to normal values only in trained animals. The present results clearly demonstrate that treadmill training alone, in a normal horizontal posture, elicited by noninvasive perineal stimulation is sufficient to induce a persistent hindlimb locomotor recovery without the need for more complex strategies. This provides a baseline level that should be clearly surpassed if additional locomotor-enabling procedures are added. Moreover, it has a clinical value since intrinsic spinal reorganization induced by training should contribute to improve locomotor recovery together with afferent feedback and supraspinal modifications in patients with incomplete SCI. PMID:26203108

  2. Spinal epidural abscess complicating vertebral osteomyelitis: an insidious cause of deteriorating spinal cord function.

    PubMed

    Lee, H J; Bach, J R; White, R E

    1992-01-01

    Spinal epidural abscess may complicate vertebral osteomyelitis. The purpose of this report is to discuss its course in two patients with sensory/motor and cognitive impairment and to demonstrate the need for its early detection. Delayed detection may lead to spinal cord injury or meningitis. It may also delay functional return and hinder intensive rehabilitation efforts. Two patients are presented. PMID:1545229

  3. Primary extramedullary spinal melanoma mimicking spinal meningioma: A case report and literature review

    PubMed Central

    LI, YU-PING; ZHANG, HENG-ZHU; SHE, LEI; WANG, XIAO-DONG; DONG, LUN; XU, ENXI; WANG, XING-DONG

    2014-01-01

    Primary spinal melanoma is a rare lesion, which occurs throughout the cranial and spinal regions, however, is primarily observed in the middle or lower thoracic spine. The clinical features of primary spinal melanoma are complex and unspecific, resulting in a high misdiagnosis rate. In the present case report, a rare case of spinal melanoma exhibiting the dural tail sign and mimicking spinal meningioma is reported. The initial diagnosis, using magnetic resonance imaging (MRI), was unclear. Thus, melanin-containing tumors and spinal meningioma should have been considered in the differential diagnosis. The tumor was completely resected using a standard posterior midline approach, which was followed by chemotherapy. Subsequent to the surgery, the patient was discharged with improved motor capacity and a follow-up MRI scan showed no recurrence after six months. The present study demonstrates that it is critical for neurosurgeons to focus on increasing the accuracy of initial diagnoses in order to make informed decisions regarding the requirement for surgical resection. The present case report presents the clinical, radiological and pathological features of primary extramedullary spinal melanoma mimicking spinal meningioma to emphasize the importance of early identification and diagnosis. PMID:24959273

  4. A School Experiment in Kinematics: Shooting from a Ballistic Cart

    ERIC Educational Resources Information Center

    Kranjc, T.; Razpet, N.

    2011-01-01

    Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…

  5. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

    ERIC Educational Resources Information Center

    Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

    2012-01-01

    Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

  6. Zero-Inertial Recession for a Kinematic Wave Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kinematic-wave models of surface irrigation assume a fixed relationship between depth and discharge (typically, normal depth). When surface irrigation inflow is cut off, the calculated upstream flow depth goes to zero, since the discharge is zero. For short time steps, use of the Kinematic Wave mode...

  7. Kinematic Signatures of Telic and Atelic Events in ASL Predicates

    ERIC Educational Resources Information Center

    Malaia, Evie; Wilbur, Ronnie B.

    2012-01-01

    This article presents an experimental investigation of kinematics of verb sign production in American Sign Language (ASL) using motion capture data. The results confirm that event structure differences in the meaning of the verbs are reflected in the kinematic formation: for example, in the telic verbs (throw, hit), the end-point of the event is…

  8. Spinal cord infarction: a rare cause of paraplegia

    PubMed Central

    Patel, Sonali; Naidoo, Khimara; Thomas, Peter

    2014-01-01

    Spinal cord infarction is rare and represents a diagnostic challenge for many physicians. There are few reported cases worldwide with a prevalence of 1.2% of all strokes. Circulation to the spinal cord is supplied by a rich anastomosis. The anterior spinal artery supplies the anterior two thirds of the spinal cord and infarction to this area is marked by paralysis, spinothalamic sensory deficit and loss of sphincter control depending on where the lesion is. Treatment of spinal cord infarction focuses on rehabilitation with diverse outcomes. This report presents a case of acute spinal cord infarction with acquisition of MRI to aid diagnosis. PMID:24966260

  9. Clinical Assessment Of Stereotactic IGRT: Spinal Radiosurgery

    SciTech Connect

    Gerszten, Peter C. Burton, Steven A.

    2008-07-01

    The role of stereotactic radiosurgery for the treatment of intracranial lesions is well established. Its use for the treatment of spinal lesions has been limited because of the availability of effective target immobilization devices. Recent advances in stereotactic IGRT have allowed for spinal applications. Large clinical experience with spinal radiosurgery to properly assess clinical outcomes has previously been limited. At our institution, we have developed a successful multidisciplinary spinal radiosurgery program in which 542 spinal lesions (486 malignant and 56 benign lesions) were treated with a single-fraction radiosurgery technique. Patient ages ranged from 18 to 85 years (mean 56 years). Lesion location included 92 cervical, 234 thoracic, 130 lumbar, and 86 sacral. The most common metastatic tumors were renal cell (89 cases), breast (74 cases), and lung (71 cases). The most common benign tumors were neurofibroma (24 cases), schwannoma (13 cases), and meningioma (7 cases). Eighty-nine cervical lesions were treated using skull tracking. Thoracic, lumbar, and sacral tumors were tracked relative to either gold or stainless steel fiducial markers. The maximum intratumoral dose ranged from 12.5 to 30 Gy (mean 20 Gy). Tumor volume ranged from 0.16 to 298 mL (mean 47 mL). Three hundred thirty-seven lesions had received prior external beam irradiation with spinal cord doses precluding further conventional irradiation. The primary indication for radiosurgery was pain in 326 cases, as a primary treatment modality in 70 cases, for tumor radiographic tumor progression in 65 cases, for post-surgical treatment in 38 cases, for progressive neurological deficit in 35 cases, and as a radiation boost in 8 cases. Follow-up period was at least 3 to 49 months. Axial and/or radicular pain improved in 300 of 326 cases (92%). Long-term tumor control was demonstrated in 90% of lesions treated with radiosurgery as a primary treatment modality and in 88% of lesions treated for

  10. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, L.C.

    1997-07-01

    An adjustable link for kinematic mounting systems is disclosed. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two. 3 figs.

  11. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, Layton C.

    1997-01-01

    An adjustable link for kinematic mounting systems. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two.

  12. Uncertainty quantification in kinematic wave models

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.

    2012-10-01

    We developed a probabilistic approach to quantify parametric uncertainty in first-order hyperbolic conservation laws (kinematic wave equations). The approach relies on the derivation of a deterministic equation for the cumulative density function (CDF) of the system state, in which probabilistic descriptions (probability density functions or PDFs) of the system parameters and/or initial and boundary conditions serve as inputs. In contrast to PDF equations, which are often used in other contexts, CDF equations allow for straightforward and unambiguous determination of boundary conditions with respect to sample variables.The accuracy and robustness of solutions of the CDF equation for one such system, the Saint-Venant equations of river flows, were investigated via comparison with Monte Carlo simulations.

  13. Beating kinematics of magnetically actuated cilia

    NASA Astrophysics Data System (ADS)

    Downton, M. T.; Stark, H.

    2009-02-01

    We study the beating kinematics and pumping performance of a magnetically actuated artificial cilium attached to a surface using a bead spring model. Several different beating patterns for the external field are considered along with the possiblity of defects in the filament at isolated points. Hydrodynamic interactions between the beads are included by a modified Rotne-Prage tensor such that the no-slip boundary condition at the surface is satisfied. We find that the correct positioning of defects along the filament length can lead to significant increases in the pumping performance of a planar beating pattern. Even more efficient for pumping fluid are three-dimensional beating strokes which bring the filament close to the surface during the return part of the stroke.

  14. Galaxy simulations: Kinematics and mock observations

    NASA Astrophysics Data System (ADS)

    Moody, Christopher E.

    2013-08-01

    There are six topics to my thesis, which are: (1) slow rotator production in varied simulation schemes and kinematically decoupled cores and twists in those simulations, (2) the change in number of clumps in radiation pressure and no-radiation pressure simulations, (3) Sunrise experiments and failures including UVJ color-color dust experiments and UVbeta slopes, (4) the Sunrise image pipeline and algorithms. Cosmological simulations of have typically produced too many stars at early times. We find that the additional radiation pressure (RP) feedback suppresses star formation globally by a factor of ~ 3. Despite this reduction, the simulation still overproduces stars by a factor of ~ 2 with respect to the predictions provided by abundance matching methods. In simulations with RP the number of clumps falls dramatically. However, only clumps with masses Mclump/Mdisk ≤ 8% are impacted by the inclusion of RP, and clump counts above this range are comparable. Above this mass, the difference between and RP and no-RP contrast ratios diminishes. If we restrict our selection to galaxies hosting at least a single clump above this mass range then clump numbers, contrast ratios, survival fractions and total clump masses show little discrepancy between RP and no-RP simulations. By creating mock Hubble Space Telescope observations we find that the number of clumps is slightly reduced in simulations with RP. We demonstrate that clumps found in any single gas, stellar, or mock observation image are not necessarily clumps found in another map, and that there are few clumps common to multiple maps. New kinematic observations from ATLAS3D have highlighted the need to understand the evolutionary mechanism leading to a spectrum of fast-rotator and slow-rotators in early-type galaxies. We address the formation of slow and fast rotators through a series of controlled, comprehensive hydrodynamic simulations sampling idealized galaxy merger formation scenarios constructed from model

  15. Relativistic kinematics for motion faster than light

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1982-01-01

    The use of conformal coordinates in relativistic kinematics is illustrated and a simple extension of the theory of motions faster than light is provided. An object traveling at a speed greater than light discloses its presence by appearing suddenly at a point, splitting into two apparent objects which then recede from each other at sublight velocities. According to the present theory motion at speeds faster than light would not benefit a space traveler, since the twin paradox becomes inverted at such speeds. In Einstein's theory travel at the velocity of light in an intertial system is equivalent to infinite velocity for the traveler. In the present theory the converse is also true; travel at infinite velocity is equivalent to the velocity of light for the traveler.

  16. Effective kinematic viscosity of turbulent He II

    SciTech Connect

    Chagovets, T. V.; Gordeev, A. V.; Skrbek, L.

    2007-08-15

    The temperature dependence of the effective kinematic viscosity of turbulent He II, {nu}{sub eff}(T), is deduced from second sound attenuation data using the late stage of decay of thermally induced counterflow He II turbulence in two channels of square cross section. It is shown to qualitatively agree with the published data for {nu}{sub eff}(T) calculated based on experiments on decaying-grid-generated He II turbulence [Niemela et al., J. Low Temp. Phys. 138, 537 (2005)]. Corrections to these data due to the 'sine squared' law that describes attenuation of the second sound wave propagating along an arbitrary direction with respect to the direction of the core of a quantized vortex in turbulent He II are discussed and applied.

  17. Kinematic Solar Dynamo with Spot Deposition

    NASA Astrophysics Data System (ADS)

    Karak, Bidya Binay; Miesch, Mark S.

    2016-05-01

    We have recently developed a kinematic dynamo model by including the observed differential rotation and the meridional flow. This model includes the emergence of sunspots from the deep-seated toroidal field and their subsequent decay at the surface, i.e., the Babcock-Leighton process for the generation of poloidal field.We shall show that this model reproduces most of the basic features of the solar magnetic cycle including the polarity reversals, 11 years periodicity, equatorward migration of sunspots at low latitudes and the poleward migration of the radial field at the surface. This model also produces the observed cycle variations when the fluctuations in the active-region tilt are included. North-south asymmetries of cycles from this model will also be demonstrated.

  18. Kinematics of chiropteran shoulder girdle in flight.

    PubMed

    Panyutina, A A; Kuznetsov, A N; Korzun, L P

    2013-03-01

    New data on the mechanisms of movements of the shoulder girdle and humerus of bats are described; potential mobility is compared to the movements actually used in flight. The study was performed on the basis of morphological and functional analysis of anatomical specimens of 15 species, high speed and high definition filming of two species and X-ray survey of Rousettus aegyptiacus flight. Our observations indicate that any excursions of the shoulder girdle in bats have relatively small input in the wing amplitude. Shoulder girdle movements resemble kinematics of a crank mechanism: clavicle plays the role of crank, and scapula-the role of connecting rod. Previously described osseous "locking mechanisms" in shoulder joint of advanced bats do not affect the movements, actually used in flight. The wing beats in bats are performed predominantly by movements of humerus relative to shoulder girdle, although these movements occupy the caudal-most sector of available shoulder mobility. PMID:23381941

  19. A kinematic model of southern California.

    USGS Publications Warehouse

    Weldon, R.; Humphreys, E.

    1986-01-01

    We propose a kinematic model for southern California based on late Quaternary slip rates and orientations of major faults in the region. Internally consistent motions are determined assuming that these faults bound rigid blocks. The velocities of the blocks are calculated along several paths that begin in the Mojave Desert and end off the California coast. A path that crosses the western Transverse Ranges accumulates the accepted relative North America-Pacific plate velocity, whereas paths to the north and south result in a significant missing component of motion. This implies the existence of a zone of active deformation in southern California that is interpreted to include the western Transverse Ranges and northwest trending, predominately strike-slip faults close to the coast both north and south of the Transverse Ranges. Strain on this system accounts for about a third of the total North America- Pacific plate motion. -from Authors

  20. SPACEBAR: Kinematic design by computer graphics

    NASA Technical Reports Server (NTRS)

    Ricci, R. J.

    1975-01-01

    The interactive graphics computer program SPACEBAR, conceived to reduce the time and complexity associated with the development of kinematic mechanisms on the design board, was described. This program allows the direct design and analysis of mechanisms right at the terminal screen. All input variables, including linkage geometry, stiffness, and applied loading conditions, can be fed into or changed at the terminal and may be displayed in three dimensions. All mechanism configurations can be cycled through their range of travel and viewed in their various geometric positions. Output data includes geometric positioning in orthogonal coordinates of each node point in the mechanism, velocity and acceleration of the node points, and internal loads and displacements of the node points and linkages. All analysis calculations take at most a few seconds to complete. Output data can be viewed at the scope and also printed at the discretion of the user.

  1. Differential Kinematics Of Contemporary Industrial Robots

    NASA Astrophysics Data System (ADS)

    Szkodny, T.

    2014-08-01

    The paper presents a simple method of avoiding singular configurations of contemporary industrial robot manipulators of such renowned companies as ABB, Fanuc, Mitsubishi, Adept, Kawasaki, COMAU and KUKA. To determine the singular configurations of these manipulators a global form of description of the end-effector kinematics was prepared, relative to the other links. On the basis of this description , the formula for the Jacobian was defined in the end-effector coordinates. Next, a closed form of the determinant of the Jacobian was derived. From the formula, singular configurations, where the determinant's value equals zero, were determined. Additionally, geometric interpretations of these configurations were given and they were illustrated. For the exemplary manipulator, small corrections of joint variables preventing the reduction of the Jacobian order were suggested. An analysis of positional errors, caused by these corrections, was presented

  2. Elbow joint instability: A kinematic model.

    PubMed

    Olsen, B S; Henriksen, M G; Søjbjerg, J O; Helmig, P; Sneppen, O

    1994-05-01

    The effect of simultaneous ulnar and radial collateral ligament division on the kinematics of the elbow joint is studied in a cadaveric model. Severance of the anterior part of the ulnar collateral ligament and the annular ligament led to significant elbow joint instability in valgus and varus stress and in forced external and internal rotation. The mean maximum laxity in valgus stress and forced external rotation were 5.7° and 13.2°. The forearms of the elbow joint specimens were transfixed in maximum pronation. During valgus and varus stress the corresponding spontaneous ulnar rotation of the specimens was recorded. The reproducibility of the instability pattern suggests that this model is suitable for evaluating stabilizing procedures aimed at correction of elbow joint instability before these procedures are introduced into patient care. PMID:22959690

  3. Global and regional kinematics from SLR stations

    NASA Technical Reports Server (NTRS)

    Dunn, Peter J.

    1994-01-01

    The stations of the Global Laser Tracking Network have significantly contributed to the measurement of plate kinematics. The expanding network of progressively improved instruments clearly demonstrates the systems' centimeter positioning accuracy. Several satellite laser ranging (SLR) analysis groups have adopted techniques to distill geodynamic information from the Lageos-1 satellite observations using orbital arc lengths from an hour to a decade. SLR observations now provide the scale for the International Terrestrial Reference System and help to define the Earth's polar motion in this system. Agreement between positions separately determined with SLR, VLBI and GPS systems has been established at the level of a few centimeters in position and a few millimeters per year in horizontal velocity.

  4. Unraveling L_{n,k}: Grassmannian Kinematics

    SciTech Connect

    Kaplan, Jared; /SLAC

    2010-02-15

    It was recently proposed that the leading singularities of the S-Matrix of N = 4 super Yang-Mills theory arise as the residues of a contour integral over a Grassmannian manifold, with space-time locality encoded through residue theorems generalizing Cauchy's theorem to more than one variable. We provide a method to identify the residue corresponding to any leading singularity, and we carry this out explicitly for all leading singularities at tree level and one-loop. We also give several examples at higher loops, including all generic two-loop leading singularities and an interesting four-loop object. As an example we consider a 12-pt N{sup 4}MHV leading singularity at two loops that has a kinematic structure involving double square roots. Our analysis results in a simple picture for how the topological structure of loop graphs is reflected in various substructures within the Grassmannian.

  5. Kinematic tests of exotic flat cosmological models

    SciTech Connect

    Charlton, J.C.; Turner, M.S.

    1986-05-01

    Theoretical prejudice and inflationary models of the very early Universe strongly favor the flat, Einstein-deSitter model of the Universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the Universe which possess a smooth component by energy density. We study in detail the kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings. We also discuss the observational tests which can be used to discriminate between these models. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations.

  6. Kinematics of Visually-Guided Eye Movements

    PubMed Central

    Hess, Bernhard J. M.; Thomassen, Jakob S.

    2014-01-01

    One of the hallmarks of an eye movement that follows Listing’s law is the half-angle rule that says that the angular velocity of the eye tilts by half the angle of eccentricity of the line of sight relative to primary eye position. Since all visually-guided eye movements in the regime of far viewing follow Listing’s law (with the head still and upright), the question about its origin is of considerable importance. Here, we provide theoretical and experimental evidence that Listing’s law results from a unique motor strategy that allows minimizing ocular torsion while smoothly tracking objects of interest along any path in visual space. The strategy consists in compounding conventional ocular rotations in meridian planes, that is in horizontal, vertical and oblique directions (which are all torsion-free) with small linear displacements of the eye in the frontal plane. Such compound rotation-displacements of the eye can explain the kinematic paradox that the fixation point may rotate in one plane while the eye rotates in other planes. Its unique signature is the half-angle law in the position domain, which means that the rotation plane of the eye tilts by half-the angle of gaze eccentricity. We show that this law does not readily generalize to the velocity domain of visually-guided eye movements because the angular eye velocity is the sum of two terms, one associated with rotations in meridian planes and one associated with displacements of the eye in the frontal plane. While the first term does not depend on eye position the second term does depend on eye position. We show that compounded rotation - displacements perfectly predict the average smooth kinematics of the eye during steady- state pursuit in both the position and velocity domain. PMID:24751602

  7. Kinematics of visually-guided eye movements.

    PubMed

    Hess, Bernhard J M; Thomassen, Jakob S

    2014-01-01

    One of the hallmarks of an eye movement that follows Listing's law is the half-angle rule that says that the angular velocity of the eye tilts by half the angle of eccentricity of the line of sight relative to primary eye position. Since all visually-guided eye movements in the regime of far viewing follow Listing's law (with the head still and upright), the question about its origin is of considerable importance. Here, we provide theoretical and experimental evidence that Listing's law results from a unique motor strategy that allows minimizing ocular torsion while smoothly tracking objects of interest along any path in visual space. The strategy consists in compounding conventional ocular rotations in meridian planes, that is in horizontal, vertical and oblique directions (which are all torsion-free) with small linear displacements of the eye in the frontal plane. Such compound rotation-displacements of the eye can explain the kinematic paradox that the fixation point may rotate in one plane while the eye rotates in other planes. Its unique signature is the half-angle law in the position domain, which means that the rotation plane of the eye tilts by half-the angle of gaze eccentricity. We show that this law does not readily generalize to the velocity domain of visually-guided eye movements because the angular eye velocity is the sum of two terms, one associated with rotations in meridian planes and one associated with displacements of the eye in the frontal plane. While the first term does not depend on eye position the second term does depend on eye position. We show that compounded rotation - displacements perfectly predict the average smooth kinematics of the eye during steady- state pursuit in both the position and velocity domain. PMID:24751602

  8. A Kinematic Study of Finswimming at Surface

    PubMed Central

    Gautier, Jimmy; Baly, Laurent; Zanone, Pier-Giorgio; Watier, Bruno

    2004-01-01

    Finswimming is a sport of speed practiced on the surface or underwater, in which performance is based on whole-body oscillations. The present study investigated the undulatory motion performed by finswimmers at the surface. This study aiming to analyze the influence of the interaction of gender, practice level, and race distance on selected kinematic parameters. Six elite and six novices finswimmers equipped with joints markers (wrist, elbow, shoulder, hip, knee, and ankle) were recorded in the sagittal plane. The position of these anatomical marks was digitized at 50 Hz. An automated motion analysis software yielded velocity, vertical amplitude, frequency, and angular position. Results showed that stroke frequency decreased whereas the mean amplitude of all joints increased with increasing race distance (p < 0.01). Mean joint amplitude for the upper limbs (wrist, elbow and shoulder) was smaller for experts than for novices. Whereas that of the ankle was larger, so that the oscillation amplitude increased from shoulder to ankle. Elite male finswimmers were pitching more acutely than female. Moreover, elite male finswimmers showed a smaller knee bending than novices and than elite females (p < 0.01). This indicated that elite male finswimmers attempt to reduce drag forces thanks to a weak knee bending and a low upper limbs pitch. To sum up, gender, expertise, and race distance affect the performance and its kinematics in terms frontal drag. Expertise in finswimming requires taking advantage of the mechanical constraints pertaining to hydrodynamic constraints in order to optimize performance. Key Points Finswimmers are at one and the same time a propelling and a propelled body. This study investigates the undulatory motion performed by finswimmers at the surface. Elite male finswimmers were pitching more acutely than female swimmers and showed a smaller knee bending than both novices and elite female swimmers. Finswimmers tended to perform a dolphin-like motion

  9. Kinematics of Baryons Cycling Through Galaxy Halos

    NASA Astrophysics Data System (ADS)

    Nielsen, Nikole M.

    2015-01-01

    In a modern view of galaxy evolution, the baryon cycle is key to understanding the observed global properties of galaxies. Red galaxies passively evolve due to quenching of their star formation, whereas blue galaxies actively evolve, presumably due to a replenishing gas supply. Signatures of the baryon cycle such as IGM accretion, minor mergers, and stellar-driven outflows and fountains are best probed in gaseous halos, i.e., the circumgalactic medium (CGM). We study the spatial and kinematic distribution of the low-ionization metal-enriched CGM with QSO absorption lines for a population of 182 galaxies in the MgII Absorber-Galaxy Catalog (MAGIICAT). We present our findings detailing how the extent and patchiness of the CGM depends on MgII absorption strength, and galaxy luminosity and color. For the first time, we placed the kinematics of 39 MgII absorbers with high-resolution spectra in the context of their host galaxy color, redshift, and orientation. By examining the velocity dispersions of absorbers, we find possible effects of quenching on red galaxies where the velocity dispersions decrease over 2 Gyrs time and are smaller at larger radii. The velocity dispersions for blue galaxies remain constant over time and radius and possibly indicate a sustained flow of baryons feeding star formation. Blue, face-on galaxies probed along the minor axis show the largest velocity dispersions to very high significance. This result provides the strongest direct evidence to date for galactic-scale outflows which, for this orientation, are pointing nearly towards the observer. We discuss how our results place observational constraints on simulations which are just now beginning to accurately model the baryon cycle and its role in galaxy evolution.

  10. Feeding kinematics of juvenile swellsharks, Cephaloscyllium ventriosum

    PubMed

    Ferry-Graham

    1997-01-01

    To investigate how feeding behaviors change with prey size, high-speed video recording was used to examine the kinematics of prey capture and transport in 1-year-old swellsharks Cephaloscyllium ventriosum (Scyliorhinidae: Carchariniformes) feeding on two differently sized prey items. Prey capture in these sharks generally consisted of an initially ram-dominated capture bite, one or more manipulation bites, a holding phase during which the food was held in the teeth of the shark, and then suction-dominated prey transport. During initial capture and transport, most of the water taken in is forced back out of the mouth anteriorly rather than continuing posteriorly out through the gill openings. Dye experiments in which dye-perfused prey items were ingested by the sharks confirm this observation; distinct jets of colored water were video-taped as they were ejected from the mouth. Very late in prey transport, a bolus of water is ejected through the gill slits; however, by this time, the majority of water appears already to have exited the buccal cavity through the mouth. Such patterns were observed for sharks feeding on both small and large prey items. Although a basic pattern of prey capture and transport was regularly repeated among strikes, kinematic patterns during prey capture and transport were variable both within and among individuals, indicating that prey acquisition is not tightly controlled. However, the amount of variability was similar among prey sizes. In addition, there were no detectable changes in behavior due to prey item size. Ram-suction index values confirmed that similar capture modes were being utilized for both prey sizes. PMID:9319118

  11. Thoracic spinal trauma and associated injuries: should early spinal decompression be considered?

    PubMed

    Petitjean, M E; Mousselard, H; Pointillart, V; Lassie, P; Senegas, J; Dabadie, P

    1995-08-01

    The relative benefits of conservative or surgical treatment in thoracic spinal trauma are still controversial. Owing to its anatomic relations, thoracic spinal trauma is specific regarding neurologic prognosis, the high incidence of associated injuries, and surgical management. Over a 30-month period, 49 patients sustained thoracic spinal trauma with neurologic impairment. The authors review population characteristics, associated injuries, and surgical management, and underline the high incidence of associated injuries, in particular, blunt chest trauma. In their opinion, early spinal decompression has no indication in complete paraplegia. Concerning partial paraplegia, early surgery may enhance neurologic recovery. Nevertheless, they suggest three main criteria in deciding whether or not to perform surgery early: the existence of residual spinal compression, the degree of neurologic impairment, and the presence of potential hemorrhagic lesions or blunt chest trauma, especially pulmonary contusion. PMID:7674409

  12. Numerical analysis of kinematic soil-pile interaction

    SciTech Connect

    Castelli, Francesco; Maugeri, Michele; Mylonakis, George

    2008-07-08

    In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.

  13. Forward and inverse kinematics of double universal joint robot wrists

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., II

    1991-01-01

    A robot wrist consisting of two universal joints can eliminate the wrist singularity problem found on many individual robots. Forward and inverse position and velocity kinematics are presented for such a wrist having three degrees of freedom. Denavit-Hartenberg parameters are derived to find the transforms required for the kinematic equations. The Omni-Wrist, a commercial double universal joint robot wrist, is studied in detail. There are four levels of kinematic parameters identified for this wrist; three forward and three inverse maps are presented for both position and velocity. These equations relate the hand coordinate frame to the wrist base frame. They are sufficient for control of the wrist standing alone. When the wrist is attached to a manipulator arm; the offset between the two universal joints complicates the solution of the overall kinematics problem. All wrist coordinate frame origins are not coincident, which prevents decoupling of position and orientation for manipulator inverse kinematics.

  14. Numerical analysis of kinematic soil—pile interaction

    NASA Astrophysics Data System (ADS)

    Castelli, Francesco; Maugeri, Michele; Mylonakis, George

    2008-07-01

    In the present study, the response of singles pile to kinematic seismic loading is investigated using the computer program SAP2000@. The objectives of the study are: (1) to develop a numerical model that can realistically simulate kinematic soil-structure interaction for piles accounting for discontinuity conditions at the pile-soil interface, energy dissipation and wave propagation; (2) to use the model for evaluating kinematic interaction effects on pile response as function of input ground motion; and (3) to present a case study in which theoretical predictions are compared with results obtained from other formulations. To evaluate the effects of kinematic loading, the responses of both the free-field soil (with no piles) and the pile were compared. Time history and static pushover analyses were conducted to estimate the displacement and kinematic pile bending under seismic loadings.

  15. Color-kinematics duality in multi-Regge kinematics and dimensional reduction

    NASA Astrophysics Data System (ADS)

    Johansson, Henrik; Vera, Agustín Sabio; Campillo, Eduardo Serna; Vázquez-Mozo, Miguel Á.

    2013-10-01

    In this note we study the applicability of the color-kinematics duality to the scattering of two distinguishable scalar matter particles with gluon emission in QCD, or graviton emission in Einstein gravity. Previous analysis suggested that direct use of the Bern-Carrasco-Johansson double-copy prescription to matter amplitudes does not reproduce the gravitational amplitude in multi-Regge kinematics. This situation, however, can be avoided by extensions to the gauge theory, while maintaning the same Regge limit. Here we present two examples of these extensions: the introduction of a scalar contact interaction and the relaxation of the distinguishability of the scalars. In both cases new diagrams allow for a full reconstruction of the correct Regge limit on the gravitational side. Both modifications correspond to theories obtained by dimensional reduction from higher-dimensional gauge theories.

  16. A study on estimation of planar gait kinematics using minimal inertial measurement units and inverse kinematics.

    PubMed

    Hu, Xinyao; Soh, Gim Song

    2014-01-01

    This paper describes a preliminary study of using four inertial measurement units (IMUs) attached to the heel and pelvis to estimate the joint angles of normal subjects during walking. The IMU, consisting of a 3-D accelerometer and gyroscope, is used to estimate the planar displacement of the heel and pelvis and the angular change of heel in one gait cycle. We then model the gait as a planar 3R serial chain and solve its inverse kinematics by using such information. The results are validated by comparing the estimated joint angles of lower limbs (i.e. hip, knee and ankle angles) with an optical motion capture system. This study can benefit the future research on conducting complete lower limbs kinematics analysis with minimal and unobtrusive wearable sensors. PMID:25571585

  17. Functional and structural recovery of the injured spinal cord in rats treated with gonadotropin-releasing hormone.

    PubMed

    Calderón-Vallejo, Denisse; Quintanar-Stephano, Andrés; Hernández-Jasso, Irma; Jiménez-Hernández, Violeta; Ruiz-Ornelas, Jannet; Jiménez, Ismael; Quintanar, J Luis

    2015-03-01

    Several studies have shown that gonadotropin-releasing hormone (GnRH) have extra-pituitary roles, including neurotrophic effects. This study was to evaluate the effects of GnRH treatment on the spinal cord injury (SCI) of rats. Ovariectomized rats were divided into: sham SCI surgery (Sham), SCI treated with saline solution (SCI + SS), and SCI treated with GnRH (SCI + GnRH). The SCI was induced by compression. One day after the lesion, SCI + GnRH group was injected with GnRH (60 µg/kg/twice/day; i.m.) for 15 days and the other groups with saline solution. To kinematic gait analysis, length and velocity of the stride were measured. In spinal cord, axonal morphometry and spared white and gray matter were analyzed by histochemistry. Protein expression of spinophilin was evaluated by western blot. The results showed that, 5 weeks after the injury, the group of animals treated with GnRH, significantly increased the length and velocity of the stride compared to SCI + SS group and they were similar to Sham group. In spinal cord, GnRH treatment increased the number and caliber of nerve axons and in the case of white matter, spared tissue was significantly higher than those animals treated with saline solution. The expression of spinophilin in spinal cord of SCI + GnRH group was slightly increased with respect to those not treated. In conclusion, GnRH treatment improves recovery of gait and decreases histopathological damage in the injured spinal cord of rat. These findings suggest that GnRH acts as a neurotrophic factor and can be used as a potential therapeutic agent for treatment of SCI. PMID:25618391

  18. Kinematic and kinetic analysis of static sitting of patients with neuropathic spine deformity.

    PubMed

    Murans, Girts; Gutierrez-Farewik, Elena M; Saraste, Helena

    2011-10-01

    Wheelchair dependent children with neuropathic and neuromuscular diseases have up to 90% risk for progressive spine deformities. An unbalanced sitting can induce progression of spinal and pelvic deformities. Many current clinical assessment methods of sitting of such patients are semi-quantitative, or questionnaire-based. A 3D movement analysis offers quantitative and objective biomechanical analysis of sitting. The aim was to validate a method to describe quiet sitting and differences between patients and controls as well as to apply the methodology for pre- and post-operative comparison. The analysis was performed on 14 patients and 10 controls. Four patients were retested after spine surgery. Seat load asymmetry was up to 30% in the patient group comparing to maximum 7% in the control group. The asymmetric position of Ground Reaction Force vector between left and right sides was significant. Plumb line of cervical 7th vertebra over sacral 1st was different only in rotation. The location of Common Center of Pressure relative to inter-trochanteric midpoint was more anterior in controls than in patients. Pelvic inclination in patients was smaller, the obliquity and rotation was similar. There were no significant differences between patients and controls of the thorax position. Results with more changes in the seat-loading domain in comparison with posture indicate good postural control compensation of spinal deformity induced disequilibrium despite neuromuscular disease in the background. The comparison of the pelvic obliquity data from kinematics and X-ray showed good correlation. The four patients tested postoperatively improved after surgery. PMID:21816615

  19. Morphometric analysis of the cervical spinal canal on MRI.

    PubMed

    Matveeva, Niki; Janevski, Petar; Nakeva, Natasha; Zhivadinovik, Julija; Dodevski, Ace

    2013-01-01

    Two useful numerical values, called the Torg ratio and the spinal canal diameter (SC diameter) are widely accepted as reliable morphometric determinants of spinal stenosis. The aims of the study were to examine morphometric determinants of the cervical spinal canal on MRI in both sexes and analyse them as reliable indicators of spinal stenosis. Measurements were made on 50 MR images (sagittal T2 weighted images from C3 to C7) of the cervical spine of patients from the Emergency Centre who had undertaken MRI of the cervical spine in addition to CT for various diagnostic indications. Torg ratio, used in evaluation of the spinal canal stenosis on plain x-ray radiographs, cannot be used as a spinal canal stenosis indicator due to the gender differences in the vertebral bodies' width. Sagittal canal diameters were more spread out in males than in females. MRI enables the value of the space available for the spinal cord, (SAC) to be determined, by subtracting the sagittal diameter of the spinal cord from the sagittal diameter of the spinal canal. Not gender, but individual and level differences in the SAC values were evident (cervical cord enlargement). SAC values relied more on the spinal canal than on the spinal cord, so that the differences in the dimensions of the spinal cord accounted for less variability in the SAC values. MR imaging of the cervical spine provides more accurate cervical canal and spinal cord measurements that could serve as morphometric determinants of the cervical canal stenosis. PMID:24280784

  20. Characteristics and rehabilitation for patients with spinal cord stab injury

    PubMed Central

    Wang, Fangyong; Zhang, Junwei; Tang, Hehu; Li, Xiang; Jiang, Shudong; Lv, Zhen; Liu, Shujia; Chen, Shizheng; Liu, Jiesheng; Hong, Yi

    2015-01-01

    [Purpose] The objective of the study was to compare the incidence, diagnosis, treatment, and prognosis of patients with spinal cord stab injury to those with the more common spinal cord contusion injury. [Subjects] Of patients hospitalized in China Rehabilitation Research Center from 1994 to 2014, 40 of those having a spinal cord stab injury and 50 with spinal cord contusion were selected. [Methods] The data of all patients were analyzed retrospectively. The cases were evaluated by collecting admission and discharge ASIA (American Spinal Injury Association) and ADL (activity of daily living) scores. [Results] After a comprehensive rehabilitation program, ASIA and ADL scores of patients having both spinal cord stab injury and spinal cord contusion significantly increase. However, the increases were noted to be higher in patients having a spinal cord stab injury than those having spinal cord contusion. [Conclusion] Comprehensive rehabilitation is effective both for patients having spinal cord stab injury and those with spinal cord contusion injury. However, the prognosis of patients having spinal cord stab injury is better than that of patients with spinal cord contusion. PMID:26834329

  1. Adiposity and spinal cord injury

    PubMed Central

    Gorgey, Ashraf S; Wells, Kathryn M; Austin, Timothy L

    2015-01-01

    The drastic changes in body composition following spinal cord injury (SCI) have been shown to play a significant role in cardiovascular and metabolic health. The pattern of storage and distribution of different types of adipose tissue may impact metabolic health variables similar to carbohydrate, lipid and bone metabolism. The use of magnetic resonance imaging provides insights on the interplay among different regional adipose tissue compartments and their role in developing chronic diseases. Regional adipose tissue can be either distributed centrally or peripherally into subcutaneous and ectopic sites. The primary ectopic adipose tissue sites are visceral, intramuscular and bone marrow. Dysfunction in the central nervous system following SCI impacts the pattern of distribution of adiposity especially between tetraplegia and paraplegia. The current editorial is focused primarily on introducing different types of adipose tissue and establishing scientific basis to develop appropriate dietary, rehabilitation or pharmaceutical interventions to manage the negative consequences of increasing adiposity after SCI. We have also summarized the clinical implications and future recommendations relevant to study adiposity after SCI. PMID:26396933

  2. Three-Dimensional Kinematic Gait Analysis of Doberman Pinschers with and without Cervical Spondylomyelopathy

    PubMed Central

    Foss, K.; da Costa, R.C.; Moore, S.

    2014-01-01

    Background The optimal treatment of cervical spondylomyelopathy (CSM) is controversial, with the owner’s and clinician’s perception of gait improvement often being used as outcome measures. These methods are subjective and suffer from observer bias. Objectives To establish kinematic gait parameters utilizing digital motion capture in normal Doberman Pinschers and compare them with CSM-affected Dobermans. Animals Nineteen Doberman Pinschers; 10 clinically normal and 9 with CSM. Methods All dogs were enrolled prospectively and fitted with a Lycra® body suit, and motion capture was performed and used to reconstruct a 3-D stick diagram representation of each dog based on 32 reflective markers, from which several parameters were measured. These included stride duration, length, and height; maximal and minimal spinal angles; elbow and stifle flexion and extension; and maximum and minimum distances between the thoracic and pelvic limbs. A random-effects linear regression model was used to compare parameters between groups. Results Significant differences between groups included smaller minimum (mean = 116 mm; P = .024) and maximum (mean = 184 mm; P = .001) distance between the thoracic limbs in CSM-affected dogs. Additionally, thoracic limb stride duration was also smaller (P = .009) in CSM-affected dogs (mean = 0.7 seconds) when compared with normal dogs (mean = 0.8 seconds). In the pelvic limbs, the average stifle flexion (mean = 100°; P = .048) and extension (mean = 136°; P = .009), as well as number of strides (mean = 2.7 strides; P = .033) were different between groups. Conclusions and Clinical Importance Our findings suggest that computerized gait analysis reveals more consistent kinematic differences in the thoracic limbs, which can be used as future objective outcome measures. PMID:23194100

  3. Novel Method for Analyzing Locomotor Ability after Spinal Cord Injury in Rats: Technical Note

    PubMed Central

    Shinozaki, Munehisa; Yasuda, Akimasa; Nori, Satoshi; Saito, Nobuhito; Toyama, Yoshiaki; Okano, Hideyuki; Nakamura, Masaya

    2013-01-01

    In the research for the treatment of spinal cord injury (SCI), the evaluation of motor function in model rats must be as objective, noninvasive, and ethical as possible. The maximum speed and acceleration of a mouse measured using a SCANET system were previously reported to vary significantly according to severity of SCI. In the present study, the motor performance of SCI model rats was examined with SCANET and assessed for Basso-Beattie-Bresnahan (BBB) score to determine the usefulness of the SCANET system in evaluating functional recovery after SCI. Maximum speed and acceleration within the measurement period correlated significantly with BBB scores. Furthermore, among several phased kinematic factors used in BBB scores, the capability of “plantar stepping” was associated with a drastic increase in maximum speed and acceleration after SCI. Therefore, evaluation of maximum speed and acceleration using a SCANET system is a useful method for rat models of SCI and can complement open field scoring scales. PMID:24097095

  4. Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    NASA Astrophysics Data System (ADS)

    García-Lorenzo, B.; Márquez, I.; Barrera-Ballesteros, J. K.; Masegosa, J.; Husemann, B.; Falcón-Barroso, J.; Lyubenova, M.; Sánchez, S. F.; Walcher, J.; Mast, D.; García-Benito, R.; Méndez-Abreu, J.; van de Ven, G.; Spekkens, K.; Holmes, L.; Monreal-Ibero, A.; del Olmo, A.; Ziegler, B.; Bland-Hawthorn, J.; Sánchez-Blázquez, P.; Iglesias-Páramo, J.; Aguerri, J. A. L.; Papaderos, P.; Gomes, J. M.; Marino, R. A.; González Delgado, R. M.; Cortijo-Ferrero, C.; López-Sánchez, A. R.; Bekeraitė, S.; Wisotzki, L.; Bomans, D.

    2015-01-01

    Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims: The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods: After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [O ii] λλ3726,3729, [O iii] λλ4959,5007, Hα+[N ii] λλ6548,6584, and [SII]λλ6716,6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [O iii] λλ4959,5007 emission line profiles. Results: At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear

  5. Spinal biomechanics and functional anatomy.

    PubMed

    Denoix, J M

    1999-04-01

    Knowledge of the normal functional behavior and mechanical properties of the vertebral column is important to understand the pathogenesis of back lesions, to identify the clinical manifestations of back pain, and to ensure a rational approach to physical therapy. The purpose of this article is to present a synthesis of in vivo and in vitro data obtained from different but complementary investigations. Presently, in vivo studies are limited; few gait-specific kinematic and electromyographic investigations are in process. Higher stresses to reach the maximal range of intervertebral motion can be applied on the spine on anatomical specimens than in living horses, and anatomical functional data can be obtained at the level of intervertebral structures. For each movement of flexion, extension, lateroflexion, and rotation, regional and intervertebral mobility is presented with an emphasis on craniocaudal variations and their anatomical causes. Because of the location of their ICR, the dorsoventral movements of a thoracolumbar intervertebral joint can be defined as a rotation around the center of the more caudal vertebral body. This information supports the new concept of intervertebral mobility in the horse and provides additional elements to facilitate understanding of the pathogenesis of back problems in the horse. PMID:10218240

  6. Robot-Assisted Arm Assessments in Spinal Cord Injured Patients: A Consideration of Concept Study

    PubMed Central

    Albisser, Urs; Rudhe, Claudia; Curt, Armin; Riener, Robert; Klamroth-Marganska, Verena

    2015-01-01

    Robotic assistance is increasingly used in neurological rehabilitation for enhanced training. Furthermore, therapy robots have the potential for accurate assessment of motor function in order to diagnose the patient status, to measure therapy progress or to feedback the movement performance to the patient and therapist in real time. We investigated whether a set of robot-based assessments that encompasses kinematic, kinetic and timing metrics is applicable, safe, reliable and comparable to clinical metrics for measurement of arm motor function. Twenty-four healthy subjects and five patients after spinal cord injury underwent robot-based assessments using the exoskeleton robot ARMin. Five different tasks were performed with aid of a visual display. Ten kinematic, kinetic and timing assessment parameters were extracted on joint- and end-effector level (active and passive range of motion, cubic reaching volume, movement time, distance-path ratio, precision, smoothness, reaction time, joint torques and joint stiffness). For cubic volume, joint torques and the range of motion for most joints, good inter- and intra-rater reliability were found whereas precision, movement time, distance-path ratio and smoothness showed weak to moderate reliability. A comparison with clinical scores revealed good correlations between robot-based joint torques and the Manual Muscle Test. Reaction time and distance-path ratio showed good correlation with the “Graded and Redefined Assessment of Strength, Sensibility and Prehension” (GRASSP) and the Van Lieshout Test (VLT) for movements towards a predefined position in the center of the frontal plane. In conclusion, the therapy robot ARMin provides a comprehensive set of assessments that are applicable and safe. The first results with spinal cord injured patients and healthy subjects suggest that the measurements are widely reliable and comparable to clinical scales for arm motor function. The methods applied and results can serve as a

  7. Imaging features of spinal tanycytic ependymoma.

    PubMed

    Tomek, Michal; Jayajothi, Anandapadmanabhan; Brandner, Sebastian; Jaunmuktane, Zane; Lee, Cheong Hung; Davagnanam, Indran

    2016-02-01

    Tanycytic ependymoma is an unusual morphological variant of WHO grade II ependymoma, typically arising from the cervical or thoracic spinal cord. Although the literature deals extensively with pathological features of this tumour entity, imaging features have not been well characterised. The purpose of this study was to review magnetic resonance imaging (MRI) features of spinal tanycytic ependymomas reported in the literature to date, exemplified by a case of a patient with tanycytic ependymoma of the conus medullaris presenting to our hospital. A Medline search of the English literature for all previously published cases of spinal tanycytic ependymoma was carried out and the reported MRI features reviewed. The tumours were found to be typically well-demarcated masses, predominantly showing isointensity on T1-weighted signal, and T2-weighted hyperintensity, with variable patterns of contrast enhancement. A cystic component was seen in half of the cases, and in a minority a mural nodule was present within the cyst wall. Associated syrinx formation was observed in one-third of the cases and haemorrhage was rare, which may be helpful pointers in differentiating the lesion from other ependymoma subtypes. In conclusion, MRI characteristics of spinal tanycytic ependymoma are variable and non-specific, and radiological diagnosis thus remains challenging, although certain predominant features are identified in this report. Knowledge of these is important in the diagnostic differentiation from other intramedullary and extramedullary spinal tumours in order to guide appropriate surgical management. PMID:26755489

  8. Stereotactic radiosurgery for intramedullary spinal arteriovenous malformations.

    PubMed

    Kalani, Maziyar A; Choudhri, Omar; Gibbs, Iris C; Soltys, Scott G; Adler, John R; Thompson, Patricia A; Tayag, Armine T; Samos, Cindy H; Chang, Steven D

    2016-07-01

    Spinal cord arteriovenous malformations (AVM) are rare lesions associated with recurrent hemorrhage and progressive ischemia. Occasionally a favorable location, size or vascular anatomy may allow management with endovascular embolization and/or microsurgical resection. For most, however, there is no good treatment option. Between 1997 and 2014, we treated 37 patients (19 females, 18 males, median age 30years) at our institution diagnosed with intramedullary spinal cord AVM (19 cervical, 12 thoracic, and six conus medullaris) with CyberKnife (Accuray, Sunnyvale, CA, USA) stereotactic radiosurgery. A history of hemorrhage was present in 50% of patients. The mean AVM volume of 2.3cc was treated with a mean marginal dose of 20.5Gy in a median of two sessions. Clinical and MRI follow-up were carried out annually, and spinal angiography was repeated at 3years. We report an overall obliteration rate of 19% without any post-treatment hemorrhagic events. In those AVM that did not undergo obliteration, significant volume reduction was noted at 3years. Although the treatment paradigm for spinal cord AVM continues to evolve, radiosurgical treatment is capable of safely obliterating or significantly shrinking most intramedullary spinal cord AVM. PMID:26869363

  9. Regression Segmentation for M³ Spinal Images.

    PubMed

    Wang, Zhijie; Zhen, Xiantong; Tay, KengYeow; Osman, Said; Romano, Walter; Li, Shuo

    2015-08-01

    Clinical routine often requires to analyze spinal images of multiple anatomic structures in multiple anatomic planes from multiple imaging modalities (M(3)). Unfortunately, existing methods for segmenting spinal images are still limited to one specific structure, in one specific plane or from one specific modality (S(3)). In this paper, we propose a novel approach, Regression Segmentation, that is for the first time able to segment M(3) spinal images in one single unified framework. This approach formulates the segmentation task innovatively as a boundary regression problem: modeling a highly nonlinear mapping function from substantially diverse M(3) images directly to desired object boundaries. Leveraging the advancement of sparse kernel machines, regression segmentation is fulfilled by a multi-dimensional support vector regressor (MSVR) which operates in an implicit, high dimensional feature space where M(3) diversity and specificity can be systematically categorized, extracted, and handled. The proposed regression segmentation approach was thoroughly tested on images from 113 clinical subjects including both disc and vertebral structures, in both sagittal and axial planes, and from both MRI and CT modalities. The overall result reaches a high dice similarity index (DSI) 0.912 and a low boundary distance (BD) 0.928 mm. With our unified and expendable framework, an efficient clinical tool for M(3) spinal image segmentation can be easily achieved, and will substantially benefit the diagnosis and treatment of spinal diseases. PMID:25361503

  10. Non-hepatocellular carcinoma spinal metastases.

    PubMed

    Goodwin, C Rory; Abu-Bonsrah, Nancy; Boone, Christine; Ruiz-Valls, Alejandro; Sankey, Eric W; Sarabia-Estrada, Rachel; Elder, Benjamin D; Kosztowski, Thomas; Sciubba, Daniel M

    2016-05-01

    Metastases to the spine from non-hepatocellular carcinomas, such as cholangiocarcinoma and angiosarcoma, occur rarely. With improvements in oncologic care, the number of patients diagnosed with metastatic cancer is expected to increase. We performed a systematic review of the literature to assess the clinical presentation, treatment, outcome and survival of patients diagnosed with non-hepatocellular carcinoma spinal metastasis using PubMed, Embase, CINAHL, Cochrane Library and Web of Science. We identified 19 cases of spinal metastases from non-hepatocellular carcinomas that fit our pre-specified criteria. The mean age at presentation was 62.3years and cholangiocarcinoma was the most common subtype. Patients frequently presented with pain, weakness or paraparesis and at the time of diagnosis, most of them had multi-level involvement of the spine. A majority of patients with spinal metastasis were treated either with radiation or chemotherapy or received no treatment. A minority of the reports included information on survival, which revealed a median survival of 1.5months following diagnosis of the spinal metastasis. Although there is a paucity of published literature on non-hepatocellular carcinoma spinal metastasis, this systematic review provides descriptive clinical characteristics of these patients. PMID:26778049

  11. Neurosyphilis manifesting as spinal transverse myelitis.

    PubMed

    Matijosaitis, Vaidas; Vaitkus, Antanas; Pauza, Valius; Valiukeviciene, Skaidra; Gleizniene, Rymante

    2006-01-01

    Spinal myelitis caused by neurosyphilis is an extremely rare disease, and there are only few visual examples of magnetic resonance imaging scans. We present a clinical case of neurosyphilis, which is of great importance concerning diagnostic, differential diagnosis, and tactics of management. A patient complaining of progressive legs weakness, numbness, and shooting-like pain in the legs as well as pelvic dysfunction was admitted to the hospital. Neurological examination revealed spinal cord lesion symptoms: legs weakness, impairment of superficial and deep sensation together with pathological symptoms in the legs. Hernia of intervertebral disc or tumor was suspected, and myelography with computed tomography of the spine was performed. No pathological findings were observed. More precise examination of the patient (a small scar in the genitals and condylomata lata in anal region were noticed) pointed to possible syphilis-induced spinal cord lesion. Serologic syphilis diagnostic tests (Treponema pallidum hemagglutination assay, reagin plasma response, serum enzyme-linked immunosorbent assay) and cerebrospinal fluid tests (general cerebrospinal fluid test and Venereal Disease Research Laboratory test) confirmed the diagnosis of neurosyphilis. Spinal cord lesion determined by magnetic resonance imaging was evaluated as spinal syphilis or syphilis-induced myelitis. Conventional treatment showed a partial effect. PMID:16778468

  12. Rehabilitation and treatment of spinal cord tumors

    PubMed Central

    Raj, Vishwa S.; Lofton, LaTanya

    2013-01-01

    Context Due to advances in acute oncological treatment, patients with spinal cord tumors exhibit improved survival. However, these patients have not received the full benefits of rehabilitation services to address their neurological deficits and rehabilitation goals. Objective To evaluate the epidemiology and pathophysiology of spinal cord tumors, address methods of acute oncological management, review treatment for neurological sequelae, and understand the implications as they relate to rehabilitation. Methods An extensive literature review was performed regarding the epidemiology, pathophysiology, acute oncological management, neurological sequelae, and rehabilitation for patients with spinal cord tumors. Databases used included pubmed.gov and OVID, as well as individual journal and textbook articles. Results Access to treatment should be increased given improved survival and functional deficits for patients with spinal cord tumors. Individuals can benefit from inpatient rehabilitation programs, in spite of increased medical co-morbidity and neurological deficits. Specific areas of improvement include functionality, mood, quality of life, and survival. Adjustments to treatment plans must incorporate medical complications from cancer and its treatment, perceived quality of life, and prognosis. Conclusions Patients with spinal cord tumors who participate in rehabilitation programs show general improvement in function, mood, quality of life, and survival. Adaptations to care plans should be made to accommodate medical co-morbidities from cancer and its treatment, patient perceptions, and prognosis. PMID:23433329

  13. Radiation tolerance of the cervical spinal cord

    SciTech Connect

    McCunniff, A.J.; Liang, M.J.

    1989-03-01

    The incidence of permanent injury to the spinal cord as a complication of radiation therapy generally correlates positively with total radiation dosage. However, several reports in the literature have indicated that fraction size is also an important factor in the development or nondevelopment of late injuries in normal tissue. To determine the effect of fraction size on the incidence of radiation-induced spinal cord injuries, we reviewed 144 cases of head and neck cancer treated at our institution between 1971 and 1980 with radiation greater than 5600 cGy to a portion of the cervical spinal cord. Most of these patients received greater than or equal to 6000 cGy, with fraction sizes ranging from 133 cGy to 200 cGy. Fifty-three of the 144 patients have been followed up for 2 years or more. Nearly half of these (26 patients) received greater than 6000 cGy with fraction sizes of 133 cGy to 180 cGy. Only 1 of the 53 (1.9%) has sustained permanent spinal cord injury; 20 months after completion of radiation treatments he developed Brown-Sequard syndrome. Our experience suggests that radiation injuries to the spinal cord correlate not only with total radiation dosage, but also with fraction size; low fraction sizes appear to decrease the incidence of such injuries.

  14. Developing therapies for spinal muscular atrophy.

    PubMed

    Wertz, Mary H; Sahin, Mustafa

    2016-02-01

    Spinal muscular atrophy is an autosomal-recessive pediatric neurodegenerative disease characterized by loss of spinal motor neurons. It is caused by mutation in the gene survival of motor neuron 1 (SMN1), leading to loss of function of the full-length SMN protein. SMN has a number of functions in neurons, including RNA splicing and snRNP biogenesis in the nucleus, and RNA trafficking in neurites. The expression level of full-length SMN protein from the SMN2 locus modifies disease severity. Increasing full-length SMN protein by a small amount can lead to significant improvements in the neurological phenotype. Currently available interventions for spinal muscular atrophy patients are physical therapy and orthopedic, nutritional, and pulmonary interventions; these are palliative or supportive measures and do not address the etiology of the disease. In the past decade, there has been a push for developing therapeutics to improve motor phenotypes and increase life span of spinal muscular atrophy patients. These therapies are aimed primarily at restoration of full-length SMN protein levels, but other neuroprotective treatments have been investigated as well. Here, we discuss recent advances in basic and clinical studies toward finding safe and effective treatments of spinal muscular atrophy using gene therapy, antisense oligonucleotides, and other small molecule modulators of SMN expression. PMID:26173388

  15. Genetics Home Reference: spinal muscular atrophy with progressive myoclonic epilepsy

    MedlinePlus

    ... myoclonic epilepsy spinal muscular atrophy with progressive myoclonic epilepsy Enable Javascript to view the expand/collapse boxes. ... All Description Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) is a neurological condition that causes ...

  16. General Information about Childhood Brain and Spinal Cord Tumors

    MedlinePlus

    ... Cord Tumors Treatment Overview (PDQ®)–Patient Version General Information About Childhood Brain and Spinal Cord Tumors Go ... types of brain and spinal cord tumors. The information from tests and procedures done to detect (find) ...

  17. Primary spinal intradural hydatid cyst--a short report.

    PubMed

    Pushparaj, K; Sundararajan, M; Madeswaran, K; Ambalavanan, S

    2001-06-01

    Primary spinal hydatid cysts are uncommon. Among these, intradural presentation is very rare. A case of primary spinal intradural hydatid cyst presenting as incomplete dorsal cord compression is reported here for its rarity. PMID:11447449

  18. Vocational Rehabilitation of Persons with Spinal Cord Injuries

    ERIC Educational Resources Information Center

    Poor, Charles R.

    1975-01-01

    Reviews historical development of organized vocational rehabilitation programming for the spinal cord injured in the United States. Significant factors that affect vocational rehabilitation outcomes with spinal cord injured persons are listed and discussed. (Author)

  19. What Are the Treatments for Spinal Cord Injury (SCI)?

    MedlinePlus

    ... Resources and Publications What are the treatments for spinal cord injury (SCI)? Skip sharing on social media links ... no known ways to reverse damage to the spinal cord. However, researchers are continually working on new treatments, ...

  20. Spinal Cord Tolerance in the Age of Spinal Radiosurgery: Lessons From Preclinical Studies

    SciTech Connect

    Medin, Paul M.; Boike, Thomas P.

    2011-04-01

    Clinical implementation of spinal radiosurgery has increased rapidly in recent years, but little is known regarding human spinal cord tolerance to single-fraction irradiation. In contrast, preclinical studies in single-fraction spinal cord tolerance have been ongoing since the 1970s. The influences of field length, dose rate, inhomogeneous dose distributions, and reirradiation have all been investigated. This review summarizes literature regarding single-fraction spinal cord tolerance in preclinical models with an emphasis on practical clinical significance. The outcomes of studies that incorporate uniform irradiation are surprisingly consistent among multiple small- and large-animal models. Extensive investigation of inhomogeneous dose distributions in the rat has demonstrated a significant dose-volume effect while preliminary results from one pig study are contradictory. Preclinical spinal cord dose-volume studies indicate that dose distribution is more critical than the volume irradiated suggesting that neither dose-volume histogram analysis nor absolute volume constraints are effective in predicting complications. Reirradiation data are sparse, but results from guinea pig, rat, and pig studies are consistent with the hypothesis that the spinal cord possesses a large capacity for repair. The mechanisms behind the phenomena observed in spinal cord studies are not readily explained and the ability of dose response models to predict outcomes is variable underscoring the need for further investigation. Animal studies provide insight into the phenomena and mechanisms of radiosensitivity but the true significance of animal studies can only be discovered through clinical trials.

  1. MRI Evaluation of Spinal Length and Vertebral Body Angle During Loading with a Spinal Compression Harness

    NASA Technical Reports Server (NTRS)

    Campbell, James A.; Hargens, Alan R.; Murthy, G.; Ballard, R. E.; Watenpaugh, D. E.; Hargens, Alan, R.; Sanchez, E.; Yang, C.; Mitsui, I.; Schwandt, D.; Fechner, K. P.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Weight bearing by the spinal column during upright posture often plays a role in the common problem of low back pain. Therefore, we developed a non-ferromagnetic spinal compression harness to enable MRI investigations of the spinal column during axial loading. Human subjects were fitted with a Nest and a footplate which were connected by adjustable straps to an analog load cell. MRI scans of human subjects (5 males and 1 female with age range of 27-53 yrs) during loaded and unloaded conditions were accomplished with a 1.5 Tesla GE Signa scanner. Studies of two subjects undergoing sequentially increasing spinal loads revealed significant decreases (r(sup 2) = 0.852) in spinal length between T4 and L5 culminating in a 1.5 to 2% length decrease during loading with 75% body weight. Sagittal vertebral body angles of four subjects placed under a constant 50% body weight load for one hour demonstrated increased lordotic and kyphotic curvatures. In the lumbar spine, the L2 vertebral body experienced the greatest angular change (-3 deg. to -5 deg.) in most subjects while in the thoracic spine, T4 angles increased from the unloaded state by +2 deg. to +9 deg. Overall, our studies demonstrate: 1) a progressive, although surprisingly small, decrease in spinal length with increasing load and 2) relatively large changes in spinal column angulation with 50% body weight.

  2. Measuring spinal canal size in lumbar spinal stenosis: description of method and preliminary results

    PubMed Central

    Makirov, Serik K.; Osadchiy, Valentin

    2015-01-01

    Background Lumbar spinal stenosis is a pathological condition of the spinal channel with its concentric narrowing with presence of specific clinical syndrome. Absence of the clear unified radiological signs is the one of the basic problems of the lumbar spinal stenosis. Purpose The authors seek to create method of assessment of the spinal canal narrowing degree, based on anatomical aspects of lumbar spinal stenosis. Study Design Development of diagnostic criteria based on analysis of a consecutive patients group and a control group. Methods Thirty seven patients (73 stenotic segments) with mean age 62,4 years old were involved in the study. Severity of clinical symptoms has been estimated by the measuring scales: Oswestry Disability Index (ODI) and Swiss Spinal Stenosis Questionnaire (SSQ). Mean number of the stenotic segments was 1.97. For all patients 8 radiological criteria have been measured. In the control group have been included 37 randomly selected patients (volunteers) in mean age of 53,4 years old without stenosis signs and narrowing of the spinal canal on the MRI imaging (73 segments total). Measurements were performed at the middle of intervertebral disc and facet joints level. Results For description of the state of spinal canal we offer the coefficient: ratio of the lateral canals total area to the cross-sectional area of the dural sac (“coefficient of stenosis”). Comparison of mean values of “coefficient of stenosis” for main and control groups showed statistically significant differences (t = -12,5; p < 0.0001). Strong statistically significant correlation with the ODI and SSS scales was revealed for the obtained coefficient (p <0.05). Conclusions In our study new method of assessment of the spinal canal narrowing degree has been applied. Promising results have been obtained in a small group of patients. It is necessary to check the data on a large sample of recommendations for its clinical application. PMID:25834777

  3. The use of dual growing rods to correct spinal deformity secondary to a low-grade spinal cord astrocytoma

    PubMed Central

    Kuhn, Elizabeth N.; Muthigi, Akhil; Frino, John; Powers, Alexander K.

    2015-01-01

    Pediatric intramedullary spinal cord astrocytomas are rare, and the majority are low grade, typically carrying a low risk of mortality, but a high risk of morbidity. Quality of life is, therefore, an important consideration in treating concomitant progressive kyphoscoliosis. Compared with fusion-based spinal stabilization, fusionless techniques may limit some complications related to early instrumentation of the developing spine. Another consideration is the timing of radiation therapy relative to both spinal maturity and spinal instrumentation. To date, there have been no reports of the use of a fusionless technique to treat spinal deformity secondary to an intramedullary spinal cord tumor. Herein, we report the use of fusionless spinal stabilization with dual growing rods in a boy with low-grade spinal cord astrocytoma after radiation therapy. PMID:26468485

  4. Spinal hemangioblastoma combined with pilocytic astrocytoma.

    PubMed

    Li, Wei-Qing; Wang, Xiang; Zhong, Nan-Zhe; Li, Yi-Ming

    2015-07-01

    The combination of vascular anomalies with gliomas is rarely seen in the CNS, and is defined as "angioglioma". However, the definition, category, and histopathogenesis of angiogliomas remain controversial. Here, we present an unusual case of spinal hemangioblastoma (HB) combined with pilocytic astrocytoma (PA). Spinal MRI revealed lesions extending from T9 to T12 segments, in a "sandwich-like" fashion. After resection of the tumor, histopathologic study confirmed the diagnosis of HB as well as PA. A comprehensive review of the literature was further conducted. We describe a case of spinal HB combined with PA, in addition we discuss the clinicopathological relationship between HB and PA under these conditions, which may facilitate the understanding of the histogenesis of an angioglioma and guide its diagnosis and treatment. PMID:26166599

  5. [Combined spinal and epidural analgesia in urology].

    PubMed

    Bovianska, N

    1995-01-01

    Combined spinal and epidural analgesia is a new concept in the field of regional anesthesia. It combines the positive qualities of spinal and epidural analgesia, and is performed by the "needle-in-needle" technique, described in the paper. This type of analgesia is practically implemented in the Clinical Center of Urology over the past few months, and shows encouraging results. This is a report on clinical experience had with 10 combined analgesia procedures, running a course free of any complications against the background of stable hemodynamics and respiration of the patients. The block induced is with 4-hour duration, and lends itself to prolongation through an epidural catheter. This renders the method variable and suited for postoperative analgesia too. The Espokan set technical devices used make puncture of the spinal-epidural space readily practicable. PMID:8648963

  6. Acute care management of spinal cord injuries.

    PubMed

    Mitcho, K; Yanko, J R

    1999-08-01

    Meeting the health care needs of the spinal cord-injured patient is an immense challenge for the acute care multidisciplinary team. The critical care nurse clinician, as well as other members of the team, needs to maintain a comprehensive knowledge base to provide the care management that is essential to the care of the spinal cord-injured patient. With the active participation of the patient and family in care delivery decisions, the health care professionals can help to meet the psychosocial and physical needs of the patient/family unit. This article provides an evidence-based, comprehensive review of the needs of the spinal cord-injured patient in the acute care setting including optimal patient outcomes, methods to prevent complications, and a plan that provides an expeditious transition to rehabilitation. PMID:10646444

  7. Spinal hemangioblastoma combined with pilocytic astrocytoma

    PubMed Central

    Li, Wei-Qing; Wang, Xiang; Zhong, Nan-Zhe; Yi-Li, Ming

    2015-01-01

    The combination of vascular anomalies with gliomas is rarely seen in the CNS, and is defined as ‘angioglioma’. However, the definition, category, and histopathogenesis of angiogliomas remain controversial. Here, we present an unusual case of spinal hemangioblastoma (HB) combined with pilocytic astrocytoma (PA). Spinal MRI revealed lesions extending from T9 to T12 segments, in a “sandwich-like” fashion. After resection of the tumor, histopathologic study confirmed the diagnosis of HB as well as PA. A comprehensive review of the literature was further conducted. We describe a case of spinal HB combined with PA, in addition we discuss the clinicopathological relationship between HB and PA under these conditions, which may facilitate the understanding of the histogenesis of an angioglioma and guide its diagnosis and treatment. PMID:26166599

  8. Ovarian Carcinoma With Isolated Spinal Cord Metastasis

    PubMed Central

    Safadi, Sarah; Rendon, Patrick; Rutledge, Teresa; Mayasy, Shadi

    2016-01-01

    Ovarian cancer metastasis to the spinal cord is quite rare, and few case reports have been published previously. Herein, we present a case of a patient who was treated for ovarian cancer and was thought to be disease free for 17 months, then presented with lower limb weakness. She was found to have a T11-T12 metastatic intramedullary spinal cord lesion. On pathology, the diagnosis of metastatic ovarian adenocarcinoma was made. This report highlights the importance of maintaining a low threshold for ovarian cancer metastases to the spinal cord when patients present with neurologic sequelae, even in the setting of normal laboratory values, as early detection can prevent permanent neurological consequences. PMID:27493975

  9. Surgical Strategies for Cervical Spinal Neurinomas

    PubMed Central

    ITO, Kiyoshi; AOYAMA, Tatsuro; MIYAOKA, Yoshinari; HORIUCHI, Tetsuyoshi; HONGO, Kazuhiro

    Cervical spinal neurinomas are benign tumors that arise from nerve roots. Based on their location, these tumors can also take the form of a dumbbell-shaped mass. Treatment strategies for these tumors have raised several controversial issues such as appropriate surgical indications and selection of surgical approaches for cervical dumbbell-shaped spinal neurinomas. In this report, we review previous literature and retrospectively analyze cervical spinal neurinoma cases that have been treated at our hospital. Surgical indications and approaches based on tumor location and severity are discussed in detail. Thus, with advances in neuroimaging and neurophysiological monitoring, we conclude that appropriate surgical approaches and intraoperative surgical manipulations should be chosen on a case-by-case basis. PMID:26119900

  10. Intractable Pruritus After Traumatic Spinal Cord Injury

    PubMed Central

    Crane, Deborah A; Jaffee, Kenneth M; Kundu, Anjana

    2009-01-01

    Background: This report describes a young woman with incomplete traumatic cervical spinal cord injury and intractable pruritus involving her dorsal forearm. Method: Case report. Findings: Anatomic distribution of the pruritus corresponded to the dermatomal distribution of her level of spinal cord injury and vertebral fusion. Symptoms were attributed to the spinal cord injury and possible cervical root injury. Pruritus was refractory to all treatments, including topical lidocaine, gabapentin, transcutaneous electrical nerve stimulation, intravenous Bier block, stellate ganglion block, and acupuncture. Conclusions: Further understanding of neuropathic pruritus is needed. Diagnostic workup of intractable pruritus should include advanced imaging to detect ongoing nerve root compression. If diagnostic studies suggest radiculopathy, epidural steroid injection should be considered. Because the autonomic nervous system may be involved in complex chronic pain or pruritic syndromes, sympatholysis via such techniques as stellate ganglion block might be effective. PMID:19777867

  11. Primary Multifocal Gliosarcoma of the Spinal Cord

    PubMed Central

    Kumar, Ramesh M.; Finn, Michael

    2016-01-01

    Gliosarcoma (GS) is a rare and exceedingly malignant neoplasm of the central nervous system. It displays clinical features similar to glioblastoma, yet is histologically unique as it harbors both gliomatous and sarcomatous cellular components. Involvement of the neuro-axis is predominantly limited to the cerebral parenchyma and meninges. Primary GS of the spinal cord is rarely encountered. We report a case of a 54 year old male who presented with 2 months of progressive, bilateral lower extremity sensory deficits. Magnetic resonance imaging of the neuro-axis revealed multiple intradural lesions involving the cervical and thoracic spinal cord without evidence of intracranial involvement. Surgical resection of a dural based, extramedullary cervical lesion and two exophytic, intramedullary thoracic lesions revealed gliosarcoma, WHO grade IV. The patient died approximately 11 months after presentation. This report confirms that GS is not limited to supratentorial involvement and can primarily affect the spinal cord. PMID:27134708

  12. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... with significant mechanical instability or deformity requiring fusion with instrumentation....

  13. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the...; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply... with significant mechanical instability or deformity requiring fusion with instrumentation....

  14. 21 CFR 888.3070 - Pedicle screw spinal system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pedicle screw spinal system. 888.3070 Section 888.3070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3070 Pedicle screw spinal system. (a) Identification. Pedicle screw spinal systems...

  15. Sexuality Counseling with Clients Who Have Spinal Cord Injuries.

    ERIC Educational Resources Information Center

    Farrow, Jeff

    1990-01-01

    Examines effects of spinal cord injury on sexuality. Discusses areas of sexual concern. Provides suggestions for treating clients with spinal cord injuries experiencing sexual difficulties. Concludes that major goal in working with clients with spinal cord injuries who have sexual difficulties should be the facilitation of a creative and…

  16. Turkish Adaptation of Spinal Cord Independence Measure--Version III

    ERIC Educational Resources Information Center

    Kesiktas, Nur; Paker, Nurdan; Bugdayci, Derya; Sencan, Sureyya; Karan, Ayse; Muslumanoglu, Lutfiye

    2012-01-01

    Various rating scales have been used to assess ability in individuals with spinal cord injury. There is no specific functional assessment scale for Turkish patients with spinal cord injury. The Spinal Cord Independence Measure (SCIM) is a specific test, which has become popular in the last decade. A study was conducted to validate and evaluate the…

  17. Atypical cause of radiculopathy - Intradural spinal arachnoid cyst.

    PubMed

    Krstačić, Antonija; Krstačić, Goran; Butković Soldo, Silva

    2016-08-01

    Intradural spinal arachnoid cysts are a relatively uncommon lesion that may be either intra, or extradural, and intradural spinal arachnoid cysts are even less common. Arachnoid cysts are cerebrospinal fluid collections in the spine that can present with neurological symptoms. The objective of this paper is to describe a rare case of radicular pain due to a spinal arachnoid cyst. PMID:27104760

  18. Power regulation of kinematic control inputs for forward flying Drosophila

    NASA Astrophysics Data System (ADS)

    MacFarlane, Kenneth; Faruque, Imraan; Sean Humbert, J.

    2014-12-01

    The choices of insect wing kinematic programs is not well understood, particularly the mechanism by which an insect selects a distortion to achieve flight control. A methodology to evaluate prospective kinematic control inputs is presented based on the reachable states when control actuation was constrained to a unit of power. The method implements a computationally-derived reduced order model of the insect's flight dynamics combined with calculation of power requirement. Four kinematic inputs are evaluated based on this criterion for a Drosophila size insect in forward flight. Stroke bias is shown to be the dominant control input using this power normalized evaluation measure.

  19. Computational neural learning formalisms for manipulator inverse kinematics

    NASA Technical Reports Server (NTRS)

    Gulati, Sandeep; Barhen, Jacob; Iyengar, S. Sitharama

    1989-01-01

    An efficient, adaptive neural learning paradigm for addressing the inverse kinematics of redundant manipulators is presented. The proposed methodology exploits the infinite local stability of terminal attractors - a new class of mathematical constructs which provide unique information processing capabilities to artificial neural systems. For robotic applications, synaptic elements of such networks can rapidly acquire the kinematic invariances embedded within the presented samples. Subsequently, joint-space configurations, required to follow arbitrary end-effector trajectories, can readily be computed. In a significant departure from prior neuromorphic learning algorithms, this methodology provides mechanisms for incorporating an in-training skew to handle kinematics and environmental constraints.

  20. Fault tolerant kinematic control of hyper-redundant manipulators

    NASA Technical Reports Server (NTRS)

    Bedrossian, Nazareth S.

    1994-01-01

    Hyper-redundant spatial manipulators possess fault-tolerant features because of their redundant structure. The kinematic control of these manipulators is investigated with special emphasis on fault-tolerant control. The manipulator tasks are viewed in the end-effector space while actuator commands are in joint-space, requiring an inverse kinematic algorithm to generate joint-angle commands from the end-effector ones. The rate-inverse kinematic control algorithm presented in this paper utilizes the pseudoinverse to accommodate for joint motor failures. An optimal scale factor for the robust inverse is derived.

  1. An adaptive inverse kinematics algorithm for robot manipulators

    NASA Technical Reports Server (NTRS)

    Colbaugh, R.; Glass, K.; Seraji, H.

    1990-01-01

    An adaptive algorithm for solving the inverse kinematics problem for robot manipulators is presented. The algorithm is derived using model reference adaptive control (MRAC) theory and is computationally efficient for online applications. The scheme requires no a priori knowledge of the kinematics of the robot if Cartesian end-effector sensing is available, and it requires knowledge of only the forward kinematics if joint position sensing is used. Computer simulation results are given for the redundant seven-DOF robotics research arm, demonstrating that the proposed algorithm yields accurate joint angle trajectories for a given end-effector position/orientation trajectory.

  2. Silencing spinal interneurons inhibits immune suppressive autonomic reflexes caused by spinal cord injury.

    PubMed

    Ueno, Masaki; Ueno-Nakamura, Yuka; Niehaus, Jesse; Popovich, Phillip G; Yoshida, Yutaka

    2016-06-01

    Spinal cord injury (SCI) at high spinal levels (e.g., above thoracic level 5) causes systemic immune suppression; however, the underlying mechanisms are unknown. Here we show that profound plasticity develops within spinal autonomic circuitry below the injury, creating a sympathetic anti-inflammatory reflex, and that chemogenetic silencing of this reflex circuitry blocks post-SCI immune suppression. These data provide new insights and potential therapeutic options for limiting the devastating consequences of post-traumatic autonomic hyperreflexia and post-injury immune suppression. PMID:27089020

  3. Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats.

    PubMed

    de la Torre Valdovinos, Braniff; Duenas Jimenez, Judith Marcela; Estrada, Ismael Jimenez; Banuelos Pineda, Jacinto; Franco Rodriguez, Nancy Elizabeth; Lopez Ruiz, Jose Roberto; Osuna Carrasco, Laura Paulina; Candanedo Arellano, Ahiezer; Duenas Jimenez, Sergio Horacio

    2016-01-01

    We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats. On the contrary, in the untreated animals, their myelin sheet was reduced to 28% at 30 days after injury (DAI), in both the ipsilateral and contralateral regions of the spinal cord. Additionally, we made hindlimb kinematics experiments to study the effects of tamoxifen on cat locomotion after the injury: at 4, 16, and 30 DAI. We observed that the ipsilateral hindlimb angular displacement (AD) of the pendulum-like movements (PLM) during gait locomotion was recovered to almost normal values in treated cats. Contralateral PLM acquired similar values to those obtained in intact cats. At 4 DAI, untreated animals showed a compensatory increment of PLM occurring in the contralateral hindlimb, which was partially recovered at 30 DAI. Our findings indicate that tamoxifen exerts a neuroprotective effect and preserves or produces myelinated axons, which could benefit the locomotion recovery in injured cats. PMID:27006979

  4. Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats

    PubMed Central

    de la Torre Valdovinos, Braniff; Duenas Jimenez, Judith Marcela; Estrada, Ismael Jimenez; Banuelos Pineda, Jacinto; Franco Rodriguez, Nancy Elizabeth; Lopez Ruiz, Jose Roberto; Osuna Carrasco, Laura Paulina; Candanedo Arellano, Ahiezer; Duenas Jimenez, Sergio Horacio

    2016-01-01

    We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats. On the contrary, in the untreated animals, their myelin sheet was reduced to 28% at 30 days after injury (DAI), in both the ipsilateral and contralateral regions of the spinal cord. Additionally, we made hindlimb kinematics experiments to study the effects of tamoxifen on cat locomotion after the injury: at 4, 16, and 30 DAI. We observed that the ipsilateral hindlimb angular displacement (AD) of the pendulum-like movements (PLM) during gait locomotion was recovered to almost normal values in treated cats. Contralateral PLM acquired similar values to those obtained in intact cats. At 4 DAI, untreated animals showed a compensatory increment of PLM occurring in the contralateral hindlimb, which was partially recovered at 30 DAI. Our findings indicate that tamoxifen exerts a neuroprotective effect and preserves or produces myelinated axons, which could benefit the locomotion recovery in injured cats. PMID:27006979

  5. Neuromuscular stimulation therapy after incomplete spinal cord injury promotes recovery of interlimb coordination during locomotion

    NASA Astrophysics Data System (ADS)

    Jung, R.; Belanger, A.; Kanchiku, T.; Fairchild, M.; Abbas, J. J.

    2009-10-01

    The mechanisms underlying the effects of neuromuscular electrical stimulation (NMES) induced repetitive limb movement therapy after incomplete spinal cord injury (iSCI) are unknown. This study establishes the capability of using therapeutic NMES in rodents with iSCI and evaluates its ability to promote recovery of interlimb control during locomotion. Ten adult female Long Evans rats received thoracic spinal contusion injuries (T9; 156 ± 9.52 Kdyne). 7 days post-recovery, 6/10 animals received NMES therapy for 15 min/day for 5 days, via electrodes implanted bilaterally into hip flexors and extensors. Six intact animals served as controls. Motor function was evaluated using the BBB locomotor scale for the first 6 days and on 14th day post-injury. 3D kinematic analysis of treadmill walking was performed on day 14 post-injury. Rodents receiving NMES therapy exhibited improved interlimb coordination in control of the hip joint, which was the specific NMES target. Symmetry indices improved significantly in the therapy group. Additionally, injured rodents receiving therapy more consistently displayed a high percentage of 1:1 coordinated steps, and more consistently achieved proper hindlimb touchdown timing. These results suggest that NMES techniques could provide an effective therapeutic tool for neuromotor treatment following iSCI.

  6. IgG4-related spinal pachymeningitis.

    PubMed

    Lu, Zhang; Tongxi, Liu; Jie, Luo; Yujuan, Jiao; Wei, Jiang; Xia, Liu; Yumin, Zheng; Xin, Lu

    2016-06-01

    The aim of this study is to study the clinical, laboratory, imaging pathology, and prognosis features of IgG4-related spinal pachymeningitis. We worked with a 55-year-old man suffering from IgG4-related spinal pachymeningitis who had the most widespread lesion in his dura mater. We also review previous related studies and discuss the clinical characteristics of this rare disease. In total, eight IgG4-related spinal pachymeningitis patients have been reported in the literature since 2009. They were mostly male patients, 51.7 ± 11.9 years old on average. Cervical and thoracic vertebrae were the most common sites for lesions. The most prominent symptom was varying numbness and weakness of the limbs and/or body associated with spinal cord compression. There was one patient (1/5) with elevated serum IgG4 levels and three patients (3/3) with increased cerebrospinal fluid (CSF) IgG4 index. Positive histopathologic findings are the strongest basis for a diagnosis. All the patients with IgG4-related spinal pachymeningitis responded well to glucocorticoid therapy. IgG4-related spinal pachymeningitis is an orphan disease that mainly occurs in cervical and thoracic vertebrae. Older males are the most susceptible group. Serum IgG4 levels were consistently normal in these cases, so analysis of CSF for IgG4 production (IgG4 index) could become a useful tool. Pathological findings remain the gold standard for diagnosis. Most patients responded favorably to glucocorticoid treatment. PMID:26567899

  7. Langerhans cell histiocytosis with multiple spinal involvement.

    PubMed

    Jiang, Liang; Liu, Xiao Guang; Zhong, Wo Quan; Ma, Qing Jun; Wei, Feng; Yuan, Hui Shu; Dang, Geng Ting; Liu, Zhong Jun

    2011-11-01

    To stress the clinical and radiologic presentation and treatment outcome of Langerhans cell histiocytosis (LCH) with multiple spinal involvements. A total of 42 cases with spinal LCH were reviewed in our hospital and 5 had multifocal spinal lesions. Multiple spinal LCH has been reported in 50 cases in the literature. All cases including ours were analyzed concerning age, sex, clinical and radiologic presentation, therapy and outcome. Of our five cases, three had neurological symptom, four soft tissue involvement and three had posterior arch extension. Compiling data from the eight largest case series of the spinal LCH reveals that 27.2% multiple vertebrae lesions. In these 55 cases, there were 26 female and 29 male with the mean age of 7.4 years (range 0.2-37). A total of 182 vertebrae were involved including 28.0% in the cervical spine, 47.8% in thoracic and 24.2% in the lumbar spine. Extraspinal LCH lesion was documented in 54.2% cases, visceral involvement in 31.1% and vertebra plana in 50% cases. Paravertebral and epidural extension were not documented in most cases. Pathological diagnosis was achieved in 47 cases including 8 open spine biopsy. The treatment strategy varied depending on different hospitals. One patient died, two had recurrence and the others had no evidence of the disease with an average of 7.2 years (range 1-21) of follow-up. Asymptomatic spinal lesions could be simply observed with or without bracing and chemotherapy is justified for multiple lesions. Surgical decompression should be reserved for the uncommon cases in which neurologic compromise does not respond to radiotherapy or progresses too rapidly for radiotherapy. PMID:20496040

  8. Metal levels in corrosion of spinal implants

    PubMed Central

    Beguiristain, Jose; Duart, Julio

    2007-01-01

    Corrosion affects spinal instrumentations and may cause local and systemic complications. Diagnosis of corrosion is difficult, and nowadays it is performed almost exclusively by the examination of retrieved instrumentations. We conducted this study to determine whether it is possible to detect corrosion by measuring metal levels on patients with posterior instrumented spinal fusion. Eleven asymptomatic patients, with radiological signs of corrosion of their stainless steel spinal instrumentations, were studied by performing determinations of nickel and chromium in serum and urine. Those levels were compared with the levels of 22 patients with the same kind of instrumentation but without evidence of corrosion and to a control group of 22 volunteers without any metallic implants. Statistical analysis of our results revealed that the patients with spinal implants without radiological signs of corrosion have increased levels of chromium in serum and urine (P < 0.001) compared to volunteers without implants. Corrosion significantly raised metal levels, including nickel and chromium in serum and urine when compared to patients with no radiological signs of corrosion and to volunteers without metallic implants (P < 0.001). Metal levels measured in serum have high sensibility and specificity (area under the ROC curve of 0.981). By combining the levels of nickel and chromium in serum we were able to identify all the cases of corrosion in our series of patients. The results of our study confirm that metal levels in serum and urine are useful in the diagnosis of corrosion of spinal implants and may be helpful in defining the role of corrosion in recently described clinical entities such as late operative site pain or late infection of spinal implants. PMID:17256156

  9. Thromboprophylaxis in spinal surgery: a survey

    PubMed Central

    2012-01-01

    Background Venous Thromboembolism (VTE) is the most common complication following major joint surgery. While attention has been focused upon the incidence of thromboembolic disease following total hip or knee arthroplasty or emergency surgery for hip fracture, there exists a gap in the medical literature examining the incidence of VTE in spinal surgery. Evidence suggests that the prevalence of DVT after spinal surgery is higher than generally recognized but with a shortage of epidemiological data, guidelines for optimal prophylaxis are limited. This survey, of individuals attending the 2009 British Association of Spinal Surgeons Annual Meeting, sought to examine prevailing trends in VTE thromboprophylaxis in spinal surgery, adherence to guideline outlined by the National Institute for Health and Clinical Excellence (NICE) and to compare selections made by orthopaedic and neurosurgeons. Methods We developed a questionnaire with eight clinical scenarios. Participants were asked to supply details on their specialty and to select which method(s) of thromboprophylaxis they would employ for each scenario. Chi squared analysis was used for statistical comparison of the questionnaire responses. Results 73% of neurosurgical respondents' and 31% of orthopaedic surgeons employed low molecular weight heparin (p < 0.001). Neurosurgeons also selected anti-embolism stockings more frequently (79% v 50%) while orthopaedic surgeons preferred mechanical prophylaxis (26% v 9%). There was no significant difference between trauma and non-trauma scenarios (p = 0.05). Conclusion There is no clear consensus in thromboprophylaxis in spinal surgery. There was a significant difference in selections across surgical disciplines with neurosurgeons more closely adhering to national guidelines. Further research examining the epidemiology of venous thromboembolism in spinal surgery and the risks-benefit relationship of thromboprophylaxis is warranted. PMID:22458927

  10. Detrusor function in suprasacral spinal cord injuries.

    PubMed

    Light, J K; Beric, A

    1992-08-01

    A total of 21 patients with chronic, stable suprasacral spinal cord injuries underwent a comprehensive neurological evaluation. A second lumbosacral lesion was excluded. The urodynamic findings were relatively constant as 95% of the patients showed detrusor hyperreflexia with elevated pressures, sphincteric dyssynergia and a competent bladder neck during the filling phase. The urodynamic findings of unexpected detrusor function in high spinal cord injury, for example areflexia and hypocontractility, should raise the clinician's suspicion that there is a lesion or dysfunction involving the sacral cord. PMID:1635134

  11. A comprehensive review of spinal arachnoiditis.

    PubMed

    Wright, Michael H; Denney, Leann C

    2003-01-01

    Spinal arachnoiditis is an insidious disease caused by an inflammatory process of the arachnoid membrane resulting from many possible causes, such as myelograms with oil-based radiographic contract agents and multiple back surgeries. Diagnosis is based on symptoms and magnetic resonance imaging. Arachnoiditis can also mimic the symptoms of other diseases, such as spinal cord tumors, cauda equina syndrome, arachnoiditis ossificans, and syringomyelia. Unfortunately, there is no cure, only treatment of the chronic symptoms. It is an incurable disease that can cause minor to severe symptoms from unexplained rashes to neurologic defects. PMID:12803151

  12. Kinematic mental simulations in abduction and deduction.

    PubMed

    Khemlani, Sangeet Suresh; Mackiewicz, Robert; Bucciarelli, Monica; Johnson-Laird, Philip N

    2013-10-15

    We present a theory, and its computer implementation, of how mental simulations underlie the abductions of informal algorithms and deductions from these algorithms. Three experiments tested the theory's predictions, using an environment of a single railway track and a siding. This environment is akin to a universal Turing machine, but it is simple enough for nonprogrammers to use. Participants solved problems that required use of the siding to rearrange the order of cars in a train (experiment 1). Participants abduced and described in their own words algorithms that solved such problems for trains of any length, and, as the use of simulation predicts, they favored "while-loops" over "for-loops" in their descriptions (experiment 2). Given descriptions of loops of procedures, participants deduced the consequences for given trains of six cars, doing so without access to the railway environment (experiment 3). As the theory predicts, difficulty in rearranging trains depends on the numbers of moves and cars to be moved, whereas in formulating an algorithm and deducing its consequences, it depends on the Kolmogorov complexity of the algorithm. Overall, the results corroborated the use of a kinematic mental model in creating and testing informal algorithms and showed that individuals differ reliably in the ability to carry out these tasks. PMID:24082090

  13. On the Kinematics of Undulator Girder Motion

    SciTech Connect

    Welch, J; /SLAC

    2011-08-18

    The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

  14. The [N II] Kinematics of R Aquarii

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Vogel, S. N.; VanBuren, D.; Strong, J. P.; Lyon, R. G.; Dorband, J. E.

    1998-01-01

    We report a kinematic study of the symbiotic star system R Aqr derived from [N H]lambda 6584 emission observations with a Fabry-Perot imaging spectrometer. The [N II] spatial structure of the R Aqr jet, first observed circa 1977, and surrounding hourglass-shaped nebulosity, due to an explosion approximately 660 years ago, are derived from 41 velocity planes spaced at approximately 12 km/s intervals. Fabry-Perot imagery shows the elliptical nebulosity comprising the waist of the hourglass shell is consistent with a circular ring expanding radially at 55 km/s as seen at an inclination angle, i approximately 70 deg. Fabry-Perot imagery shows the two-sided R Aqr jet is collimated flow in opposite directions. The intensity-velocity structure of the strong NE jet component is shown in contrast to the amorphous SW jet component. We offer a idealized schematic model for the R Aqr jet motion which results in a small-scale helical structure forming around a larger-scale helical path. The implications of such a jet model are discussed. We present a movie showing a side-by-side comparison of the spatial structure of the model and the data as a function of the 41 velocity planes.

  15. Growth rate degeneracies in kinematic dynamos

    NASA Astrophysics Data System (ADS)

    Favier, B.; Proctor, M. R. E.

    2013-09-01

    We consider the classical problem of kinematic dynamo action in simple steady flows. Due to the adjointness of the induction operator, we show that the growth rate of the dynamo will be exactly the same for two types of magnetic boundary conditions: the magnetic field can be normal (infinite magnetic permeability, also called pseudovacuum) or tangent (perfect electrical conductor) to the boundaries of the domain. These boundary conditions correspond to well-defined physical limits often used in numerical models and relevant to laboratory experiments. The only constraint is for the velocity field u to be reversible, meaning there exists a transformation changing u into -u. We illustrate this surprising property using S2T2 type of flows in spherical geometry inspired by [Dudley and James, Proc. R. Soc. London A1364-502110.1098/rspa.1989.0112 425, 407 (1989)]. Using both types of boundary conditions, it is shown that the growth rates of the dynamos are identical, although the corresponding magnetic eigenmodes are drastically different.

  16. Kinematic mental simulations in abduction and deduction

    PubMed Central

    Khemlani, Sangeet Suresh; Mackiewicz, Robert; Bucciarelli, Monica; Johnson-Laird, Philip N.

    2013-01-01

    We present a theory, and its computer implementation, of how mental simulations underlie the abductions of informal algorithms and deductions from these algorithms. Three experiments tested the theory’s predictions, using an environment of a single railway track and a siding. This environment is akin to a universal Turing machine, but it is simple enough for nonprogrammers to use. Participants solved problems that required use of the siding to rearrange the order of cars in a train (experiment 1). Participants abduced and described in their own words algorithms that solved such problems for trains of any length, and, as the use of simulation predicts, they favored “while-loops” over “for-loops” in their descriptions (experiment 2). Given descriptions of loops of procedures, participants deduced the consequences for given trains of six cars, doing so without access to the railway environment (experiment 3). As the theory predicts, difficulty in rearranging trains depends on the numbers of moves and cars to be moved, whereas in formulating an algorithm and deducing its consequences, it depends on the Kolmogorov complexity of the algorithm. Overall, the results corroborated the use of a kinematic mental model in creating and testing informal algorithms and showed that individuals differ reliably in the ability to carry out these tasks. PMID:24082090

  17. Kinematic analysis of rope skipper's stability

    NASA Astrophysics Data System (ADS)

    Ab Ghani, Nor Atikah; Rambely, Azmin Sham

    2014-06-01

    There are various kinds of jumping that can be done while performing rope skipping activity. This activity was always associated with injury. But, if the rope skipper can perform the activity in a right way, it is believed that the injury might be reduced. The main purpose of this paper is to observe the stability of rope skipper from a biomechanics perspective, which are the centre of mass, angle at the ankle, knee and hip joints and also the trajectory for the ipsilateral leg between the two types of skip which is one leg and two legs. Six healthy, physically active subject, two males and four females (age: 8.00±1.25 years, weight: 17.90±6.85 kg and height: 1.22±0.08 m) participated in this study. Kinematic data of repeated five cycles of rope skipping activity was captured by using Vicon Nexus system. Based on the data collected, skipping with two legs shows more stable behavior during preparation, flight and landing phases. It is concluded that landing on the balls of the feet, lowering the trajectory positions of the feet from the ground as well as flexion of each joint which would reduce the injury while landing.

  18. Learning Kinematic Constraints in Laparoscopic Surgery

    PubMed Central

    Huang, Felix C.; Mussa-Ivaldi, Ferdinando A.; Pugh, Carla M.; Patton, James L.

    2012-01-01

    To better understand how kinematic variables impact learning in surgical training, we devised an interactive environment for simulated laparoscopic maneuvers, using either 1) mechanical constraints typical of a surgical “box-trainer” or 2) virtual constraints in which free hand movements control virtual tool motion. During training, the virtual tool responded to the absolute position in space (Position-Based) or the orientation (Orientation-Based) of a hand-held sensor. Volunteers were further assigned to different sequences of target distances (Near-Far-Near or Far-Near-Far). Training with the Orientation-Based constraint enabled much lower path error and shorter movement times during training, which suggests that tool motion that simply mirrors joint motion is easier to learn. When evaluated in physically constrained (physical box-trainer) conditions, each group exhibited improved performance from training. However, Position-Based training enabled greater reductions in movement error relative to Orientation-Based (mean difference: 14.0 percent; CI: 0.7, 28.6). Furthermore, the Near-Far-Near schedule allowed a greater decrease in task time relative to the Far-Near-Far sequence (mean −13:5 percent, CI: −19:5, −7:5). Training that focused on shallow tool insertion (near targets) might promote more efficient movement strategies by emphasizing the curvature of tool motion. In addition, our findings suggest that an understanding of absolute tool position is critical to coping with mechanical interactions between the tool and trocar. PMID:23293709

  19. Bat flight: aerodynamics, kinematics and flight morphology.

    PubMed

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. PMID:25740899

  20. Virtual sine arm kinematic mount system

    SciTech Connect

    Xu, Z.; Randall, K.J.

    1997-09-01

    A novel kinematic mount system for a vertical focusing mirror of the soft x-ray spectroscopy beamline at the Advanced Photon Source is described. The system contains three points in a horizontal plane. Each point consists of two horizontal linear precision stages, a spherical ball bearing, and a vertical precision stage. The horizontal linear stages are aligned orthogonally and are conjoined by a spherical ball bearing, supported by the vertical linear stage at each point. The position of each confined horizontal stage is controlled by a motorized micrometer head by spring-loading the flat tip of the micrometer head onto a tooling ball fixing on the carriage of the stage. A virtual sine arm is formed by tilting the upstream horizontal stage down and the two downstream horizontal stages up by a small angle. The fine pitch motion is achieved by adjusting the upstream stage. This supporting structure is extremely steady due to a relatively large span across the supporting points and yields extremely high resolution on the pitch motion. With a one degree tilt and a microstepping motor, the authors achieved a 0.4 nanoradian resolution on the mirror pitch motion.

  1. GLOBAL H I KINEMATICS IN DWARF GALAXIES

    SciTech Connect

    Stilp, Adrienne M.; Dalcanton, Julianne J.; Warren, Steven R.; Skillman, Evan; Ott, Juergen; Koribalski, Baerbel

    2013-03-10

    H I line widths are typically interpreted as a measure of interstellar medium turbulence, which is potentially driven by star formation (SF). In an effort to better understand the possible connections between line widths and SF, we have characterized H I kinematics in a sample of nearby dwarf galaxies by co-adding line-of-sight spectra after removing the rotational velocity to produce average global H I line profiles. These ''superprofiles'' are composed of a central narrow peak ({approx}6-10 km s{sup -1}) with higher-velocity wings to either side that contain {approx}10%-15% of the total flux. The superprofiles are all very similar, indicating a universal global H I profile for dwarf galaxies. We compare characteristics of the superprofiles to various galaxy properties, such as mass and measures of SF, with the assumption that the superprofile represents a turbulent peak with energetic wings to either side. We use these quantities to derive average scale heights for the sample galaxies. When comparing to physical properties, we find that the velocity dispersion of the central peak is correlated with ({Sigma}{sub HI}). The fraction of mass and characteristic velocity of the high-velocity wings are correlated with measures of SF, consistent with the picture that SF drives surrounding H I to higher velocities. While gravitational instabilities provide too little energy, the SF in the sample galaxies does provide enough energy through supernovae, with realistic estimates of the coupling efficiency, to produce the observed superprofiles.

  2. Turbulent Particle Pair Diffusion Using Kinematic Simulations

    NASA Astrophysics Data System (ADS)

    Malik, Nadeem

    2015-11-01

    Sweeping errors in Kinematic Simulations (KS) have been shown to be negligible in turbulent flows with extended inertial subranges up to at least 1 in KS may therefore be a genuine effect, challenging previous assumptions that in turbulence with generalized power-law energy spectra, E (k) ~k-p for 1 <= 3, locality would lead to, K ~σΔγ , where σΔ = [ <Δ2 > ]1/2 , Δ is the pair separation, v is the pair relative velocity, < > is the ensemble average, and γ = (1 + p) / 2 . For Kolmogorov turbulence this gives, K ~σΔ4 / 3 . A new analysis, supported by KS confirms that both local and non-local effects govern the pair diffusion process, leading to, K ~σΔγp , where now γp > γ for Kolmogorov turbulence, K ~σΔ1 . 53 . Thus non-local diffusional processes cannot be neglected, and this may have important consequences for the general theory of turbulence. The author acknowledge financial support from SABIC, #SB101011.

  3. Kinematics and trajectory generation for MIRADAS arms

    NASA Astrophysics Data System (ADS)

    Sabater, J.; Gómez, J. M.; Torra, J.; López, M.; Raines, S. N.; Eikenberry, S. S.

    2015-05-01

    The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is a NIR multi-object spectrograph for the Gran Telescopio Canarias (GTC). The instrument has a multiplexing system (MXS) that enables the simultaneous observation of twenty objects located within its field of view. These user selected targets are acquired by twenty deployable robotic probe arms with pickoff mirror optics operating at cryogenic temperatures. The MIRADAS probe arm is a close-loop mechanism designed with optics simplicity in mind, presenting good stability when it is operated upside down. Calculating optimum collision-free trajectories requires a good knowledge of the MIRADAS arm behavior based on its geometry and its mechanical constraints. This study introduces a geometric model for the two degree-of-freedom (DoF) mechanism, including solutions for the forward and inverse kinematics problem. The concepts of zone-of-avoidance (ZoA), workspace and envelope of MIRADAS arm are presented and studied. Finally, the paper proposes two different patrolling approaches that can be exploited when planning trajectories.

  4. SHIELD: Neutral Gas Kinematics and Dynamics

    NASA Astrophysics Data System (ADS)

    McNichols, Andrew; Teich, Yaron; Cannon, John M.; SHIELD Team

    2016-01-01

    The "Survey of HI in Extremely Low-mass Dwarfs" (SHIELD) is a multiwavelength, legacy-class observational study of 12 low-mass dwarf galaxies discovered in Arecibo Legacy Fast ALFA (ALFALFA) survey data products. Here we present new results of detailed kinematic analyses of these systems using multi-configuration, high spatial (˜300 pc) and spectral (0.82 - 2.46 km s-1 ch-1) resolution HI observations from the Karl G. Jansky Very Large Array. For each source, we produce velocity fields and dispersion maps using different spatial and spectral resolution representations of the data in order to attempt derivation of an inclination-corrected rotation curve. While both two- and three-dimensional fitting techniques are employed, the comparable magnitudes of velocity dispersion and projected rotation result in degeneracies that prohibit unambiguous circular velocity solutions. We thus make multiple position-velocity cuts across each galaxy to determine the maximum circular rotation velocity (≤ 30 km-1 for the survey population). Baryonic masses are calculated using single-dish H I fluxes from Arecibo and stellar masses derived from HST and Spitzer imaging. Comparison is made with total dynamical masses estimated from the position-velocity analysis. The SHIELD galaxies are contextualized on the baryonic Tully-Fisher relation.Support for this work was provided by NSF grant AST-1211683 to JMC at Macalester College.

  5. Kinematic dynamo, supersymmetry breaking, and chaos

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Igor V.; Enßlin, Torsten A.

    2016-04-01

    The kinematic dynamo (KD) describes the growth of magnetic fields generated by the flow of a conducting medium in the limit of vanishing backaction of the fields onto the flow. The KD is therefore an important model system for understanding astrophysical magnetism. Here, the mathematical correspondence between the KD and a specific stochastic differential equation (SDE) viewed from the perspective of the supersymmetric theory of stochastics (STS) is discussed. The STS is a novel, approximation-free framework to investigate SDEs. The correspondence reported here permits insights from the STS to be applied to the theory of KD and vice versa. It was previously known that the fast KD in the idealistic limit of no magnetic diffusion requires chaotic flows. The KD-STS correspondence shows that this is also true for the diffusive KD. From the STS perspective, the KD possesses a topological supersymmetry, and the dynamo effect can be viewed as its spontaneous breakdown. This supersymmetry breaking can be regarded as the stochastic generalization of the concept of dynamical chaos. As this supersymmetry breaking happens in both the diffusive and the nondiffusive cases, the necessity of the underlying SDE being chaotic is given in either case. The observed exponentially growing and oscillating KD modes prove physically that dynamical spectra of the STS evolution operator that break the topological supersymmetry exist with both real and complex ground state eigenvalues. Finally, we comment on the nonexistence of dynamos for scalar quantities.

  6. The kinematics of halo red giants

    NASA Astrophysics Data System (ADS)

    Carney, B. W.; Latham, D. W.

    1986-07-01

    The authors have obtained 337 radial velocities with typical accuracies of ± 0.7 km s-1 for 85 metal-poor field red giants, selected from the kinematically unbiased samples of Bond (1980) and Bidelman and MacConnell (1973). The multiply observed stars suggest the field halo giant binary fraction exceeds 10%. Using their own velocities and those published by others, the authors have a sample of 174 red giants with [Fe/H] ≤ -1.5. Their mean motion with respect to the local standard of rest is >V< = -206±23 km s-1, and the velocity dispersions are σR = 154±18 km s-1, σθ = 102±27 km s-1, and σφ = 107±15 km s-1. Using photometrically derived absolute magnitudes and published proper motions, the authors compute orbital eccentricities for 72 stars not already considered in a similar study of southern stars by Norris, Bessell, and Pickles (1985). They find a few (5% - 8%) stars with e < 0.4.

  7. Kinematics of the scaphoid shift test.

    PubMed

    Wolfe, S W; Gupta, A; Crisco, J J

    1997-09-01

    Twenty-five uninjured subjects (50 wrists) were examined clinically and fluoroscopically during performance of the scaphoid shift test. Wrists were placed into 3 groups on the basis of the degree of palpable carpal motion that occurred during the clinical examination. Kinematic parameters of rotation and displacement were calculated from digitized images of the carpals at rest and at maximum displacement. On clinical exam, 36% of normal individuals had positive findings on scaphoid shift test. Dorsal displacement of the scaphoid was not significantly associated with positive scaphoid shift test results in these subjects, while total displacement of the scaphoid (the sum of axial and dorsal displacement) was significantly associated with positive test results. The principle confounding factor appeared to be a high degree of displacement that occurred at the capitolunate joint in some individuals, termed a "midcarpal shift." The data demonstrate that despite a high prevalence of positive scaphoid shifts among uninjured individuals, the ability to accurately detect dorsal displacement of the scaphoid using the scaphoid shift test is limited. On the basis of their findings, the authors recommend that positive test results be confirmed fluoroscopically. PMID:9330136

  8. Thermally Insulating, Kinematic Tensioned-Fiber Suspension

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    2004-01-01

    A salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic-demagnetization refrigerator (ADR) is presented. "Salt pill" in this context denotes a unit comprising a cylindrical container, a matrix of gold wires in the container, and a cylinder of ferric ammonium alum (a paramagnetic salt) that has been deposited on the wires. The structural members used in this system for both thermal insulation and positioning are aromatic polyamide fibers (Kevlar(R) or equivalent) under tension. This suspension system is designed to satisfy several special requirements to ensure the proper operation of the ADR. These requirements are to (1) maintain the salt pill at a specified position within the cylindrical bore of an electromagnet; (2) prevent vibrations, which would cause dissipation of heat in the salt pill; and (3) minimize the conduction of heat from the electromagnet bore and other neighboring objects to the salt pill; all while (4) protecting the salt pill (which is fragile) against all tensile and bending loads other than those attributable to its own weight. In addition, the system is required to consist of two subsystems -- one for the top end and one for the bottom end of the salt pill -- that can be assembled and tensioned separately from each other and from the salt pill, then later attached to the salt pill.

  9. Feeding underground: kinematics of feeding in caecilians.

    PubMed

    Herrel, Anthony; Measey, G John

    2012-11-01

    Caecilians are limbless amphibians that have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Observations on feeding behavior are rare and restricted to above-ground feeding in laboratory conditions. Here we report data on feeding in tunnels using both external video and X-ray recordings of caecilians feeding on invertebrate prey. Our data show feeding kinematics similar to those previously reported, including the pronounced neck bending observed during above-ground feeding. Our data illustrate, however, that caecilians may be much faster than previously suspected, with lunge speeds of up to 7 cm sec(-1). Although gape cycles are often slow (0.67 ± 0.29 sec), rapid jaw closure is observed during prey capture, with cycle times and jaw movement velocities similar to those observed in other terrestrial tetrapods. Finally, our data suggest that gape angles may be large (64.8 ± 18°) and that gape profiles are variable, often lacking distinct slow and fast opening and closing phases. These data illustrate the importance of recording naturalistic feeding behavior and shed light on how these animals are capable of capturing and processing prey in constrained underground environments. Additional data on species with divergent cranial morphologies would be needed to better understand the co-evolution between feeding, burrowing, and cranial design in caecilians. PMID:22927194

  10. Compensatory mechanisms during walking in response to muscle weakness in spinal muscular atrophy, type III.

    PubMed

    Matjacić, Zlatko; Olensek, Andrej; Krajnik, Janez; Eymard, Bruno; Zupan, Anton; Praznikar, Ales

    2008-05-01

    Our knowledge on altered neurological control of walking due to weakness of various muscle groups of the lower extremities is limited. The aim of this study was to assess kinematic, kinetic and electromyographic (EMG) walking patterns in a functionally homogeneous group of seven subjects with spinal muscular atrophy, type III (SMA group) and compare them with normal data obtained from nine healthy subjects (CONTROL group) in order to identify characteristic compensatory changes. Muscle strength at the ankle and knee joints was assessed using isokinetic dynamometry to determine variability in muscle strength: this was found to be similar in the two groups. Kinematic, kinetic and EMG patterns were assessed during walking in the SMA and CONTROL groups. The results showed changes in the activity of ankle plantarflexors and associated control of the center of pressure during loading response and midstance, which facilitated minimization of the external flexion moment acting on the knee and hip in the SMA group. Additionally, we identified distinct and consistent changes in the control of hip rotators that act to rapidly extend the hip early in stance phase and in the control of contralateral hip abductors that act delay weight shift onto the leg entering the stance phase. From these results we can conclude that the most important muscle groups compensating for reduced strength in knee and hip muscles are the ankle plantarflexors, hip rotators and hip abductors. This finding would have direct application in rehabilitation treatment programs. PMID:17980600

  11. Characterization of recovered walking patterns and motor control after contusive spinal cord injury in rats

    PubMed Central

    Hansen, Christopher N; Linklater, William; Santiago, Raquel; Fisher, Lesley C; Moran, Stephanie; Buford, John A; Michele Basso, D

    2012-01-01

    Currently, complete recovery is unattainable for most individuals with spinal cord injury (SCI). Instead, recovery is typically accompanied by persistent sensory and motor deficits. Restoration of preinjury function will likely depend on improving plasticity and integration of these impaired systems. Eccentric muscle actions require precise integration of sensorimotor signals and are predominant during the yield (E2) phase of locomotion. Motor neuron activation and control during eccentric contractions is impaired across a number of central nervous system (CNS) disorders, but remains unexamined after SCI. Therefore, we characterized locomotor recovery after contusive SCI using hindlimb (HL) kinematics and electromyographic (EMG) recordings with specific consideration of eccentric phases of treadmill (TM) walking. Deficits in E2 and a caudal shift of locomotor subphases persisted throughout the 3-week recovery period. EMG records showed notable deficits in the semitendinosus (ST) during yield. Unlike other HL muscles, recruitment of ST changed with recovery. At 7 days, the typical dual-burst pattern of ST was lost and the second burst (ST2) was indistinct. By 21 days, the dual-burst pattern returned, but latencies remained impaired. We show that ST2 burst duration is highly predictive of open field Basso, Beattie, Bresnahan (BBB) scores. Moreover, we found that simple changes in locomotor specificity which enhance eccentric actions result in new motor patterns after SCI. Our findings identify a caudal shift in stepping kinematics, irregularities in E2, and aberrant ST2 bursting as markers of incomplete recovery. These residual impairments may provide opportunities for targeted rehabilitation. PMID:23139900

  12. Percutaneous Radiofrequency Ablation of Painful Spinal Tumors Adjacent to the Spinal Cord with Real-Time Monitoring of Spinal Canal Temperature: A Prospective Study

    SciTech Connect

    Nakatsuka, Atsuhiro Yamakado, Koichiro; Takaki, Haruyuki; Uraki, Junji; Makita, Masashi; Oshima, Fumiyoshi; Takeda, Kan

    2009-01-15

    PurposeTo prospectively evaluate the feasibility, safety, and clinical utility of bone radiofrequency (RF) ablation with real-time monitoring of the spinal canal temperature for the treatment of spinal tumors adjacent to the spinal cord.Materials and MethodsOur Institutional Review Board approved this study. Patients gave informed consent. The inclusion criteria were (a) a painful spinal metastasis and (b) a distance of 1 cm or less between the metastasis and the spinal cord. The thermocouple was placed in the spinal canal under CT fluoroscopic guidance. When the spinal canal temperature reached 45{sup o}C, RF application was immediately stopped. RF ablation was considered technically successful when the procedure was performed without major complications. Clinical success was defined as a fall in the visual analogue scale score of at least 2 points.ResultsTen patients with spinal tumors measuring 3-8 cm (mean, 4.9 {+-} 1.5 cm) were enrolled. The distance between the tumor and the spinal cord was 1-6 mm (mean, 2.4 {+-} 1.6 mm). All procedures were judged technically successful (100%). The spinal canal temperature did not exceed 45{sup o}C in 9 of the 10 patients (90%). In the remaining patient, the temperature rose to 48{sup o}C, resulting in transient neural damage, although RF application was immediately stopped when the temperature reached 45{sup o}C. Clinical success was achieved within 1 week in all patients (100%).ConclusionBone RF ablation with real-time monitoring of the spinal canal temperature is feasible, safe, and clinically useful for the treatment of painful spinal metastases adjacent to the spinal cord.

  13. Effects of serotonergic medications on locomotor performance in humans with incomplete spinal cord injury.

    PubMed

    Leech, Kristan A; Kinnaird, Catherine R; Hornby, T George

    2014-08-01

    Incomplete spinal cord injury (iSCI) often results in significant motor impairments that lead to decreased functional mobility. Loss of descending serotonergic (5HT) input to spinal circuits is thought to contribute to motor impairments, with enhanced motor function demonstrated through augmentation of 5HT signaling. However, the presence of spastic motor behaviors in SCI is attributed, in part, to changes in spinal 5HT receptors that augment their activity in the absence of 5HT, although data demonstrating motor effects of 5HT agents that deactivate these receptors are conflicting. The effects of enhancement or depression of 5HT signaling on locomotor function have not been thoroughly evaluated in human iSCI. Therefore, the aim of the current study was to investigate acute effects of 5HT medications on locomotion in 10 subjects with chronic (>1 year) iSCI. Peak overground and treadmill locomotor performance, including measures of gait kinematics, electromyographic (EMG) activity, and oxygen consumption, were assessed before and after single-dose administration of either a selective serotonin reuptake inhibitor (SSRI) or a 5HT antagonist using a double-blinded, randomized, cross-over design. Results indicate that neither medication led to improvements in locomotion, with a significant decrease in peak overground gait speed observed after 5HT antagonists (from 0.8±0.1 to 0.7±0.1 m/s; p=0.01). Additionally, 5-HT medications had differential effects on EMG activity, with 5HT antagonists decreasing extensor activity and SSRIs increasing flexor activity. Our data therefore suggest that acute manipulation of 5HT signaling, despite changes in muscle activity, does not improve locomotor performance after iSCI. PMID:24742292

  14. Kinematical and Chemical Vertical Structure of the Galactic Thick Disk. I. Thick Disk Kinematics

    NASA Astrophysics Data System (ADS)

    Moni Bidin, C.; Carraro, G.; Méndez, R. A.

    2012-03-01

    The variation of the kinematical properties of the Galactic thick disk with Galactic height Z is studied by means of 412 red giants observed in the direction of the south Galactic pole up to 4.5 kpc from the plane. We confirm the non-null mean radial motion toward the Galactic anticenter found by other authors, but we find that it changes sign at |Z| = 3 kpc, and the proposed inward motion of the local standard of rest alone cannot explain these observations. The rotational velocity decreases with |Z| by -30 km s-1 kpc-1, but the data are better represented by a power law with index 1.25, similar to that proposed from the analysis of Sloan Digital Sky Survey data. All the velocity dispersions increase with |Z|, but the vertical gradients are small. The dispersions grow proportionally, with no significant variation of the anisotropy. The ratio σU/σW = 2 suggests that the thick disk could have formed from a low-latitude merging event. The vertex deviation increases with Galactic height, reaching ~20° at |Z| = 3.5 kpc. The tilt angle also increases, and the orientation of the ellipsoid in the radial-vertical plane is constantly intermediate between the alignment with the cylindrical and the spherical coordinate systems. The tilt angle at |Z| = 2 kpc coincides with the expectations of MOdified Newtonian Dynamics, but an extension of the calculations to higher |Z| is required to perform a conclusive test. Finally, between 2.5 and 3.5 kpc we detect deviations from the linear trend of many kinematical quantities, suggesting that some kinematical substructure could be present. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (proposal IDs 075.B-0459(A), 077.B-0348(A)). This paper includes data gathered with the 6.5 m Magellan and the duPont Telescopes, located at Las Campanas Observatory, Chile.

  15. Software architecture for a kinematically dissimilar master-slave telethesis for exploring rehabilitation applications

    NASA Astrophysics Data System (ADS)

    Wunderlich, Joseph; Chen, Shoupu; Pino, D.; Rahman, Tariq; Harwin, William S.

    1993-12-01

    A person with limited arm and hand function could benefit from technology based on teleoperation principles, particularly where the mechanism provides proprioceptive-like information to the operator giving an idea of the forces encountered in the environment and the positions of the slave robot. A test-bed system is being prepared to evaluate the potential for adapting telemanipulator technology to the needs of people with high level spinal cord injury. This test-bed uses a kinematically dissimilar master and slave pair and will be adaptable to a variety of disabilities. The master will be head controlled and when combined with auxiliary functions will provide the degrees of freedom necessary to attempt any task. In the simplest case, this mapping could be direct, with the slave amplifying the person's movements and forces. It is unrealistic however to expect that the operator will have the range of head movement required for accurate operation of the slave over the full workspace. Neither is it likely that the person will be able to achieve simultaneous and independent control of the 6 or more degrees of freedom required to move the slave. Thus a set of more general mappings must be available that can be chosen to relate to the intrinsic coordinates of the task. The software structure to implement the control of this master-slave system is based on two IBM PC computers linked via an ethernet.

  16. The Kinematics of the Lag-Luminosity Relationship

    SciTech Connect

    Salmonson, J D

    2004-03-17

    Herein I review the argument that kinematics, i.e. relativistic motions of the emitting source in gamma-ray bursts (GRBs), are the cause of the lag-luminosity relationship observed in bursts with known redshifts.

  17. The Case for Including Eulerian Kinematics in Undergraduate Dynamics.

    ERIC Educational Resources Information Center

    Uram, Earl M.

    A Eulerian framework is proposed as an alternative to the Lagrangian framework usually used in undergraduate dynamics courses. An attempt to introduce Eulerian kinematics into a dynamics course is discussed. (LMH)

  18. Kinematic distributions for electron pair production by muons

    NASA Technical Reports Server (NTRS)

    Linsker, R.

    1972-01-01

    Cross sections and kinematic distributions for the trident production process plus or negative muon plus charge yields plus or minus muon plus electron plus positron plus charge (with charge = dipion moment and Fe) are given for beam energies of 100 to 300 GeV at fixed (electron positron) masses from 5 to 15 GeV. This process is interesting as a test of quantum electrodynamics at high energies, and in particular as a test of the form of the photon propagator at large timelike (four-momentum) squared. For this purpose, it is desirable to impose kinematic cuts that favor those Bethe-Heitler graphs which contain a timelike photon propagator. It is found that there are substantial differences between the kinematic distributions for the full Bethe-Heitler matrix element and the distributions for the two timelike-photon graphs alone; these differences can be exploited in the selection of appropriate kinematic cuts.

  19. Enhancement of Kinematic Accelerations by Wavenumber Correlation Filtering.

    PubMed

    Hong, Chang-Ki; Kwon, Jay Hyoun

    2016-01-01

    To obtain kinematic accelerations with high accuracy and reliability, multiple Global Positioning System (GPS) receivers with a single antenna can be used for airborne gravimetry. The data collected from each receiver can be processed for kinematic accelerations that may be combined using simple averaging. Here, however, uncorrelated errors from instrument errors in each receiver also will be included that degrade the final solutions. Therefore, in this study, the wavenumber correlation filter (WCF) is applied to extract only the higher positively correlated wavenumber components of the kinematic accelerations for the enhancement of the final solution. The in situ airborne GPS data from two receivers were wavenumber-correlation-filtered to show about 0.07835 Gal improvement in accuracy relative to the solution from the raw kinematic accelerations. PMID:27608026

  20. STAR CLUSTERS IN M31: OLD CLUSTERS WITH BAR KINEMATICS

    SciTech Connect

    Morrison, Heather; Harding, Paul; Caldwell, Nelson; Schiavon, Ricardo P.; Athanassoula, E.

    2011-01-01

    We analyze our accurate kinematical data for the old clusters in the inner regions of M31. These velocities are based on high signal-to-noise Hectospec data. The data are well suited for analysis of M31's inner regions because we took particular care to correct for contamination by unresolved field stars from the disk and bulge in the fibers. The metal-poor clusters show kinematics that are compatible with a pressure-supported spheroid. The kinematics of metal-rich clusters, however, argue for a disk population. In particular the innermost region (inside 2 kpc) shows the kinematics of the x{sub 2} family of bar periodic orbits, arguing for the existence of an inner Lindblad resonance in M31.

  1. Neurologic Complication Following Spinal Epidural Anesthesia in a Patient with Spinal Intradural Extramedullary Tumor

    PubMed Central

    Kim, Sung Hoon; Son, Dong Wuk; Lee, Sang Won

    2010-01-01

    Paraplegia following spinal epidural anesthesia is extremely rare. Various lesions for neurologic complications have been documented in the literature. We report a 66-year-old female who developed paraplegia after left knee surgery for osteoarthritis under spinal epidural anesthesia. In the recovery room, paraplegia and numbness below T4 vertebra was checked. A magnetic resonance image (MRI) scan showed a spinal thoracic intradural extramedullary (IDEM) tumor. After extirpation of the tumor, the motor weakness improved to the grade of 3/5. If a neurologic deficit following spinal epidural anesthesia does not resolve, a MRI should be performed without delay to accurately diagnose the cause of the deficit and optimal treatment should be rendered for the causative lesion. PMID:21430985

  2. Kinematic analysis of platform-type robotic manipulators

    NASA Astrophysics Data System (ADS)

    Shi, Xiaolun

    New methods are developed for the kinematic analysis of serial and platform-type parallel robotic manipulators, including forward and inverse kinematic solutions, singularity identifications and workspace evaluation. Differences between serial and platform-type parallel manipulators, which can provide substantially improved end-point rigidity compared with the conventional serial robotic arms, are addressed. The problem of determining the screw parameters of rigid body motion from initial and final position data is discussed, as a basis to search for a general and efficient procedure to solve the complex forward kinematics problem of platform-type manipulators. Several Screw-Theory based approaches for solving the inverse instantaneous problem of 6 DOF serial manipulators are studied and compared in terms of their computational efficiency, accuracy, sensitivity to data error and capability of dealing with singularities. A modified Vector Decomposition method is then proposed for solving the IIK problem and for singularity analysis of serial kinematic chains, the method is especially effective when applied to the wrist partitioned serial manipulators, which are essential components to any platform-type parallel manipulators. By using the data of three point positions, velocities, and accelerations of the end effector a general method is developed for solving the forward kinematics problem, including position, velocity and acceleration kinematics, of platform-type manipulators. The solution procedure can be applied to a wide variety of platform-type manipulators such as the 6 DOF Steward Platform manipulator and other models. It is found that while the solution for the forward position kinematics of a platform-type manipulator can be obtained by solving a non-linear system of equations, the closed-form solutions for forward rate and acceleration kinematics can be found by solving a system of linear equations. Based on the proposed kinematic formulations, an algorithm

  3. Imaging diagnosis--spinal cord histiocytic sarcoma in a dog.

    PubMed

    Taylor, Amanda; Eichelberger, Bunita; Hodo, Carolyn; Cooper, Jocelyn; Porter, Brian

    2015-01-01

    A 12-year-old mixed breed dog was presented for evaluation of progressive paraparesis and ataxia. Magnetic resonance (MR) imaging was performed and identified multifocal intradural spinal cord mass lesions. The lesions were hyperintense in T2-weighted sequences, isointense to mildly hyperintense in T1-weighted sequences with strong contrast enhancement of the intradural lesions and spinal cord meninges. Spinal cord neoplasia was suspected. A diagnosis of intramedullary spinal cord histiocytic sarcoma, confined to the central nervous system, was confirmed histopathologically. Spinal cord histiocytic sarcoma is a rare neoplasm, but should be included in the differential diagnosis for dogs with clinical signs of myelopathy. PMID:24382300

  4. Surgical resection of subependymoma of the cervical spinal cord.

    PubMed

    Tan, Lee A; Kasliwal, Manish K; Mhanna, Nakhle; Fontes, Ricardo B V; Traynelis, Vincent C

    2014-09-01

    Subependymomas can rarely occur in the spinal cord, and account for about 2% of symptomatic spinal cord tumors. It most often occurs in the cervical spinal cord, followed by cervicothoracic junction, thoracic cord and conus medullaris. It often has an eccentric location in the spinal cord and lacks gadolinium enhancement on magnetic resonance imaging. We present a rare case of symptomatic subependymoma of the cervical spinal cord, which underwent successful gross total resection. Surgical pearls and nuances are discussed to help surgeons to avoid potential complications. The video can be found here: http://youtu.be/Rsm9KxZX7Yo. PMID:25175581

  5. Spinal Dysraphism: A Neurosurgical Review for the Urologist

    PubMed Central

    Netto, José Murillo B; Bastos, André N; Figueiredo, André A; Pérez, Luis M

    2009-01-01

    Spinal neural tube defects are congenital malformations of the spine and spinal cord (eg, myelomeningocele) and are frequently seen in pediatric urology practice. These neurologic problems have many consequences in a child’s life and affect different parts of the body, such as the brain, spinal cord, limbs, bladder, and bowels. Because of the complexity and neurologic aspects of spinal dysraphism, many related terms and aspects of the disease are unfamiliar to the urologist. This review addresses some of the most commonly used neurosurgical terms and concepts related to spinal dysraphism. PMID:19680528

  6. Novalis Stereotactic Radiosurgery for Spinal Dural Arteriovenous Fistula

    PubMed Central

    Sung, Kyoung-Su; Song, Young-Jin

    2016-01-01

    The spinal dural arteriovenous fistula (SDAVF) is rare, presenting with progressive, insidious symptoms, and inducing spinal cord ischemia and myelopathy, resulting in severe neurological deficits. If physicians have accurate and enough information about vascular anatomy and hemodynamics, they achieve the good results though the surgery or endovascular embolization. However, when selective spinal angiography is unsuccessful due to neurological deficits, surgery and endovascular embolization might be failed because of inadequate information. We describe a patient with a history of vasospasm during spinal angiography, who was successfully treated by spinal stereotactic radiosurgery using Novalis system. PMID:27446527

  7. Elucidation of kinematical and dynamical structure of the Galactic bulge

    NASA Astrophysics Data System (ADS)

    Yano, T.; Gouda, N.; Ueda, H.; Koyama, H.; Kan-ya, Y.; Taruya, A.

    2008-07-01

    Future space mission of astrometric satellite, GAIA and JASMINE (Japan Astrometry Satellite Mission for Infrared Exploration), will produce astrometric parameter, such as positions, parallaxes, and proper motions of stars in the Galactic bulge. Then kinematical information will be obtained in the future. Accordingly it is expected that our understanding of the dynamical structure will be greatly improved. Therefore it is important to make a method to construct a kinematical and dynamical structure of the Galactic bulge immediately.

  8. Interplanetary stream magnetism: Kinematic effects. [solar magnetic fields and wind

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1974-01-01

    The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.

  9. Stewart platform kinematics and secondary mirror aberration control

    NASA Astrophysics Data System (ADS)

    Schipani, P.; Marty, L.

    2006-06-01

    This work deals with active correction of the aberrations in a telescope by moving the secondary mirror. A special attention is here dedicated to the case of a secondary mirror whose motions are controlled by a 6-6 Stewart Platform (generally called by astronomers simply "hexapod", even if this term is more general). The kinematics of the device is studied; an iterative algorithm to solve the non trivial forward kinematics problem is described.

  10. Inverse kinematics problem in robotics using neural networks

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin B.; Lawrence, Charles

    1992-01-01

    In this paper, Multilayer Feedforward Networks are applied to the robot inverse kinematic problem. The networks are trained with endeffector position and joint angles. After training, performance is measured by having the network generate joint angles for arbitrary endeffector trajectories. A 3-degree-of-freedom (DOF) spatial manipulator is used for the study. It is found that neural networks provide a simple and effective way to both model the manipulator inverse kinematics and circumvent the problems associated with algorithmic solution methods.

  11. Surgical management of multilevel cervical spinal stenosis and spinal cord injury complicated by cervical spine fracture

    PubMed Central

    2014-01-01

    Background There are few reports regarding surgical management of multilevel cervical spinal stenosis with spinal cord injury. Our purpose is to evaluate the safety and feasibility of open-door expansive laminoplasty in combination with transpedicular screw fixation for the treatment of multilevel cervical spinal stenosis and spinal cord injury in the trauma population. Methods This was a retrospective study of 21 patients who had multilevel cervical spinal stenosis and spinal cord injury with unstable fracture. An open-door expansive posterior laminoplasty combined with transpedicular screw fixation was performed under persistent intraoperative skull traction. Outcome measures included postoperative improvement in Japanese Orthopedic Association (JOA) score and incidence of complications. Results The average operation time was 190 min, with an average blood loss of 437 ml. A total of 120 transpedicular screws were implanted into the cervical vertebrae between vertebral C3 and C7, including 20 into C3, 34 into C4, 36 into C5, 20 into C6, and 10 into C7. The mean preoperative JOA score was 3.67 ± 0.53. The patients were followed for an average of 17.5 months, and the average JOA score improved to 8.17 ± 1.59, significantly higher than the preoperative score (t = 1.798, P < 0.05), with an average improvement of 44.7 ± 11.7%. Postoperative complications in four patients included cerebrospinal fluid leakage, delayed wound healing, pulmonary infection, and urinary system infection. All four patients were responsive to antibiotic treatment; one died from respiratory failure 3 months postoperatively. Conclusions The open-door expansive laminoplasty combined with posterior transpedicular screw fixation is feasible for treating multilevel cervical spinal stenosis and spinal cord injury complicated by unstable fracture. Its advantages include minimum surgical trauma, less intraoperative blood loss, and satisfactory stable supportive effect for

  12. Spinal Cord and Spinal Nerve Root Involvement (Myeloradiculopathy) in Tuberculous Meningitis

    PubMed Central

    Gupta, Rahul; Garg, Ravindra Kumar; Jain, Amita; Malhotra, Hardeep Singh; Verma, Rajesh; Sharma, Praveen Kumar

    2015-01-01

    Abstract Most of the information about spinal cord and nerve root involvement in tuberculous meningitis is available in the form of isolated case reports or case series. In this article, we evaluated the incidence, predictors, and prognostic impact of spinal cord and spinal nerve root involvement in tuberculous meningitis. In this prospective study, 71 consecutive patients of newly diagnosed tuberculous meningitis were enrolled. In addition to clinical evaluation, patients were subjected to magnetic resonance imaging (MRI) of brain and spine. Patients were followed up for at least 6 months. Out of 71 patients, 33 (46.4%) had symptoms/signs of spinal cord and spinal nerve root involvement, 22 (30.9%) of whom had symptoms/signs at enrolment. Eleven (15.4%) patients had paradoxical involvement. Paraparesis was present in 22 (31%) patients, which was of upper motor neuron type in 6 (8.4%) patients, lower motor neuron type in 10 (14%) patients, and mixed type in 6 (8.4%) patients. Quadriparesis was present in 3 (4.2%) patients. The most common finding on spinal MRI was meningeal enhancement, seen in 40 (56.3%) patients; in 22 (30.9%), enhancement was present in the lumbosacral region. Other MRI abnormalities included myelitis in 16 (22.5%), tuberculoma in 4 (5.6%), cerebrospinal fluid (CSF) loculations in 4 (5.6%), cord atrophy in 3 (4.2%), and syrinx in 2 (2.8%) patients. The significant predictor associated with myeloradiculopathy was raised CSF protein (>250 mg/dL). Myeloradiculopathy was significantly associated with poor outcome. In conclusion, spinal cord and spinal nerve root involvement in tuberculous meningitis is common. Markedly raised CSF protein is an important predictor. Patients with myeloradiculopathy have poor outcome. PMID:25621686

  13. The Association of Scapular Kinematics and Glenohumeral Joint Pathologies

    PubMed Central

    LUDEWIG, PAULA M.; REYNOLDS, JONATHAN F.

    2009-01-01

    SYNOPSIS There is a growing body of literature associating abnormal scapular positions and motions, and, to a lesser degree, clavicular kinematics with a variety of shoulder pathologies. The purpose of this manuscript is to (1) review the normal kinematics of the scapula and clavicle during arm elevation, (2) review the evidence for abnormal scapular and clavicular kinematics in glenohumeral joint pathologies, (3) review potential biomechanical implications and mechanisms of these kinematic alterations, and (4) relate these biomechanical factors to considerations in the patient management process for these disorders. There is evidence of scapular kinematic alterations associated with shoulder impingement, rotator cuff tendinopathy, rotator cuff tears, glenohumeral instability, adhesive capsulitis, and stiff shoulders. There is also evidence for altered muscle activation in these patient populations, particularly, reduced serratus anterior and increased upper trapezius activation. Scapular kinematic alterations similar to those found in patient populations have been identified in subjects with a short rest length of the pectoralis minor, tight soft-tissue structures in the posterior shoulder region, excessive thoracic kyphosis, or with flexed thoracic postures. This suggests that attention to these factors is warranted in the clinical evaluation and treatment of these patients. The available evidence in clinical trials supports the use of therapeutic exercise in rehabilitating these patients, while further gains in effectiveness should continue to be pursued. PMID:19194022

  14. The complexity of South China Sea kinematics

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  15. The Relationships between Logical Thinking, Gender, and Kinematics Graph Interpretation Skills

    ERIC Educational Resources Information Center

    Bektasli, Behzat; White, Arthur L.

    2012-01-01

    Problem Statement: Kinematics is one of the topics in physics where graphs are used broadly. Kinematics includes many abstract formulas, and students usually try to solve problems with those formulas. However, using a kinematics graph instead of formulas might be a better option for problem solving in kinematics. Graphs are abstract…

  16. Simplified spinal cord phantom for evaluation of SQUID magnetospinography

    NASA Astrophysics Data System (ADS)

    Adachi, Y.; Oyama, D.; Somchai, N.; Kawabata, S.; Uehara, G.

    2014-05-01

    Spinal cord functional imaging by magnetospinography (MSG) is a noninvasive diagnostic method for spinal cord diseases. However, the accuracy and spatial resolution of lesion localization by MSG have barely been evaluated in detail so far. We developed a simplified spinal cord phantom for MSG evaluation. The spinal cord phantom is composed of a cylindrical vessel filled with saline water, which acts as a model of a neck. A set of modeled vertebrae is arranged in the cylindrical vessel, which has a neural current model made from catheter electrodes. The neural current model emulates the current distribution around the activated site along the axon of the spinal cord nerve. Our MSG system was used to observe the magnetic field from the phantom; a quadrupole-like pattern of the magnetic field distribution, which is a typical distribution pattern for spinal cord magnetic fields, was successfully reproduced by the phantom. Hence, the developed spinal cord phantom can be used to evaluate MSG source analysis methods.

  17. Spinal cord ischemia is multifactorial: what is the best protocol?

    PubMed

    Melissano, Germano; Bertoglio, Luca; Mascia, Daniele; Rinaldi, Enrico; Del Carro, Ubaldo; Nardelli, Pasquale; Chiesa, Roberto

    2016-04-01

    Despite the improved understanding of spinal cord anatomy and spinal cord ischemia pathophysiology, the rate of debilitating postoperative paraparesis or paraplegia is still not negligible after procedures for thoracic or thoracoabdominal aortic disease. Single studies have demonstrated the role of different treatment modalities to prevent or treat spinal cord ischemia. A multimodal approach, however, is advocated by most authors. Even after the employment of endovascular techniques become routine, the rate of spinal cord ischemia after treatment of thoracoabdominal aortic pathology remained unchanged over time. Spinal cord ischemia is often treatable by different means that concur to improve indirect spinal perfusion through collateral circulation; it should, therefore, be managed promptly and aggressively due to its potential reversibility. Ongoing technical improvements of non-invasive diagnostic tools may allow a better preoperative assessment of the spinal vascular network and a better planning of both open and endovascular thoracic or thoracoabdominal repair. PMID:26731537

  18. Relief of superior mesenteric artery syndrome with correction of multiplanar spinal deformity by posterior spinal fusion.

    PubMed

    Marecek, Geoffrey S; Barsness, Katherine A; Sarwark, John F

    2010-07-01

    Superior mesenteric artery syndrome is obstruction of the third portion of the duodenum by compression between the abdominal aorta and superior mesenteric artery. Pediatric orthopedists are familiar with this entity, as the association between superior mesenteric artery syndrome and spinal fusion or body casting has been well established. However, patients with spinal deformities usually experience superior mesenteric artery syndrome after orthopedic intervention, with rates after corrective spinal surgery reported between 0.5% and 2.4%. Symptoms of superior mesenteric artery syndrome typically include nausea, bilious emesis, abdominal pain, early satiety, and anorexia. Initial treatment focuses on gastric decompression and maintaining euvolemia and electrolyte balance. The patient should receive enteral nutrition via nasojejunal tube or parenteral nutrition to allow for weight gain and subsequent resolution of the obstruction. The superior mesenteric artery takes off from the duodenum at an angle of 45 degrees to 60 degrees in normal individuals. The third portion of the duodenum is suspended between these vessels by the ligament of Treitz. Any variation in this relationship that decreases the arteriomesenteric angle may induce obstruction. Specifically, lumbar hyperextension or hyperlordosis can traction the mesentery and vessels. Only 2 cases of superior mesenteric artery syndrome in patients with sagittal plane spinal deformity have been described in the literature. In patients with concomitant superior mesenteric artery syndrome and spinal deformity, correction of the deformity may help alleviate the obstruction and result in faster recovery. The contribution of spinal column deformity to the arteriomesenteric angle should not be overlooked. PMID:20608618

  19. [Magnetic resonance tomography in late sequelae of spinal and spinal cord injuries].

    PubMed

    Kravtsov, A K; Akhadov, T A; Sachkova, I Iu; Belov, S A; Chernenko, O A; Panova, M M

    1993-01-01

    Magnetic-resonance tomography (MRT) helped obtain a high-resolution image characterized by high sensitivity in respect of soft tissue contrast visualization and providing direct imaging of the spinal cord and its radicles. This method is useful in the diagnosis of injuries to the spine and cord. A total of 64 patients of both sexes aged 6 to 67 were examined. The primary diagnosis of traumatic changes in the spine and cord was confirmed by MRT in only 62% of cases. Two groups of patients were singled out: with acute and chronic injuries, subdivided into subgroups with and without spinal cord dysfunction. The detected changes were divided into extramedullary (traumatic disk hernias, compression of the cord or radicles with a dislocated bone fragment, epidural hematoma) and intramedullary (edema, hemorrhages, spinal cord disruption); MRT diagnosis of intramedullary changes is particularly important, more so in the absence of bone injuries. In remote periods after the trauma the clinical picture was determined by spinal canal stenosis, cicatricial atrophic and adhesive changes eventually blocking the liquor space. Intramedullary changes presented as spinal cord cysts or syringomyelia. A classification of the detected changes by the types of injuries and their aftereffects is presented in the paper. The authors emphasize the desirability of MRT in spinal injuries with signs of cord dysfunction. PMID:7801568

  20. Global and regional kinematics with GPS

    NASA Technical Reports Server (NTRS)

    King, Robert W.

    1994-01-01

    The inherent precision of the doubly differenced phase measurement and the low cost of instrumentation made GPS the space geodetic technique of choice for regional surveys as soon as the constellation reached acceptable geometry in the area of interest: 1985 in western North America, the early 1990's in most of the world. Instrument and site-related errors for horizontal positioning are usually less than 3 mm, so that the dominant source of error is uncertainty in the reference frame defined by the satellites orbits and the tracking stations used to determine them. Prior to about 1992, when the tracking network for most experiments was globally sparse, the number of fiducial sites or the level at which they could be tied to an SLR or VLBI reference frame usually, set the accuracy limit. Recently, with a global network of over 30 stations, the limit is set more often by deficiencies in models for non-gravitational forces acting on the satellites. For regional networks in the northern hemisphere, reference frame errors are currently about 3 parts per billion (ppb) in horizontal position, allowing centimeter-level accuracies over intercontinental distances and less than 1 mm for a 100 km baseline. The accuracy of GPS measurements for monitoring height variations is generally 2-3 times worse than for horizontal motions. As for VLBI, the primary source of error is unmodeled fluctuations in atmospheric water vapor, but both reference frame uncertainties and some instrument errors are more serious for vertical than horizontal measurements. Under good conditions, daily repeatabilities at the level of 10 mm rms were achieved. This paper will summarize the current accuracy of GPS measurements and their implication for the use of SLR to study regional kinematics.