Lateral neck injury assessments in side impact using post mortem human subject tests.

Current neck injury criteria are based on matching upper cervical spine injuries from piglet tests to airbag deployment loads and pairing kinematics from child dummies. These "child-based" scaled data together with adult human cadaver tolerances in axial loading are used to specify neck injury thresholds in axial compression and tension, and flexion and extension moment about the occipital condyles; no thresholds are specified for any other force or moment including lateral bending. The objective of this study was to develop a testing methodology and to determine the lateral bending moment injury threshold under coronal loading.

Biomechanical properties of human thoracic spine disc segments.

Background: The objective was to determine the age-dependent compressive and tensile properties of female and male thoracic spine segments using postmortem human subjects (PMHS).

Materials And Methods: Forty-eight thoracic disc segments at T4-5, T6-7, T8-9, and T10-11 levels from 12 PMHS T3-T11 spinal columns were divided into groups A and B based on specimen age and loaded in compression and tension. Stiffness and elastic modulus were computed.

Persistent first intersegmental vertebral artery in association with type II odontoid fracture: surgical treatment utilizing a novel C1 posterior arch screw: case report.

Objective And Importance: Posterior cervical stabilization for cervical fractures is common, and numerous techniques for fixation have been described. This case describes the novel usage of C1 laminar screws due to a persistent intersegmental artery and congenital fusion of C2-C3.

Clinical Presentation: A 64-year-old woman presented with loss of consciousness after falling down a flight of stairs.

Biomechanical implications of extending occipitocervical instrumentation to include the subaxial spine.

Background: No clear biomechanical data exist regarding where to place the caudal end of a screw-rod occipitocervical instrumentation construct.

Objective: This study examines whether range of motion (ROM) from the occiput to C2 is altered by subaxial extension of occipitocervical instrumentation constructs.

Methods: Cadaver specimens underwent intact biomechanical testing followed by destabilization via an odontoid osteotomy.

Trends and variations in cervical spine surgery in the United States: Medicare beneficiaries, 1992 to 2005.

Study Design: Retrospective cohort.

Objective: To describe population-based trends and variations in surgery for degenerative changes of the cervical spine among Medicare beneficiaries, 1992 to 2005.

Summary Of Background Data: Degenerative changes of the cervical spine are seen radiographically in over half of the population aged 55 years or greater, and rates of cervical spine surgery have increased over time.

Comparison of contemporary occipitocervical instrumentation techniques with and without C1 lateral mass screws.

Objective: This study was designed to test the kinematic properties of three occiput-C2 instrumentation constructs with and without supplemental rigid C1 fixation. The results are compared with intact specimens and with constructs incorporating contemporary cabling techniques.

Methods: Five unembalmed human cadaver specimens underwent range of motion (ROM) testing in the intact condition, followed by destabilization with odontoid osteotomy.

Level-dependent coronal and axial moment-rotation corridors of degeneration-free cervical spines in lateral flexion.

Background: Aging, trauma, or degeneration can affect intervertebral kinematics. While in vivo studies can determine motions, moments are not easily quantified. Previous in vitro studies on the cervical spine have largely used specimens from older individuals with varying levels of degeneration and have shown that moment-rotation responses under lateral bending do not vary significantly by spinal level.

Anatomical, biomechanical, and practical considerations in posterior occipitocervical instrumentation.

Background Context: Patients with cervical myelopathy secondary to craniocervical instability commonly present with spinal cord compression secondary to a combination of static forces and gross instability. Craniocervical arthrodesis is therefore indicated in the treatment of the majority of these conditions. In order to facilitate arthrodesis, techniques for occipitocervical instrumentation have been developed.

Validation of a clinical finite element model of the human lumbosacral spine.

Very few finite element models on the lumbosacral spine have been reported because of its unique biomechanical characteristics. In addition, most of these lumbosacral spine models have been only validated with rotation at single moment values, ignoring the inherent nonlinear nature of the moment-rotation response of the spine. Because a majority of lumbar spine surgeries are performed between L4 and S1 levels, and the confidence in the stress analysis output depends on the model validation, the objective of the present study was to develop a unique finite element model of the lumbosacral junction.

Single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis: surgical technique and results in 15 patients.

Objective: Circumferential reconstruction and arthrodesis can be necessary after thoracolumbar vertebrectomy. The authors describe a technique for single-stage thoracolumbar vertebrectomy with circumferential reconstruction and arthrodesis. The surgical results using this technique are reviewed.

Cervical ventral epidural pressure response to graded spinal canal compromise and spinal motion.

Study Design: A laboratory investigation using a feline model of graded ventral spinal canal compromise was performed.

Objective: To quantify the effects of graded ventral spinal canal compromise, both in the static condition and in combination with passive spinal motion, on cervical ventral epidural pressure (CVEP). The CVEP effects of laminectomy are also investigated.

Reversal of neurologic deficit in an adult gorilla with severe symptomatic lumbar stenosis.

Study Design: A case report is presented.

Objective: To describe a case of severe symptomatic lumbar stenosis in an adult gorilla successfully treated with decompressive surgery.

Summary Of Background Data: Although spinal degenerative disease is thought to be less common in apes than in humans, gorillas and bonobos are known to have higher rates of disease than other African apes.

Retroperitoneal lateral lumbar interbody fusion with titanium threaded fusion cages.

Object: Intertransverse arthrodesis in which instrumentation is placed is associated with an excellent fusion rate; however, treatment of patients with symptomatic nonunion presents a number of difficulties. Revision posterior and traditional anterior procedures are associated with methodological problems. For example, in the latter, manipulation of the major vessels from L-2 to L-4 may be undesirable.