Tissue engineering strategies in spinal arthrodesis: the clinical imperative and challenges to clinical translation.

Skeletal disorders requiring the regeneration or de novo production of bone present considerable reconstructive challenges and are one of the main driving forces for the development of skeletal tissue engineering strategies. The skeletal or mesenchymal stem cell is a fundamental requirement for osteogenesis and plays a pivotal role in the design and application of these strategies. Research activity has focused on incorporating the biological role of the mesenchymal stem cell with the developing fields of material science and gene therapy in order to create a construct that is not only capable of inducing host osteoblasts to produce bone, but is also osteogenic in its own right. This review explores the clinical need for reparative approaches in spinal arthrodesis, identifying recent tissue engineering strategies employed to promote spinal fusion, and considers the ongoing challenges to successful clinical translation.

Lumbar spine fusion and stabilization: hardware, techniques, and imaging appearances.

Stabilization and fusion of the lumbar spine may be performed by using various anterior and posterior surgical techniques and a wide range of devices, including screws, spinal wires, artificial ligaments, vertebral cages, and artificial disks. Because spinal procedures are increasingly common, such devices are seen more and more often in everyday radiologic practice. For evaluation of the postoperative spine, radiography is the modality most commonly used. Computed tomography and magnetic resonance (MR) imaging may be useful alternatives, but MR imaging of the postoperative spine is vulnerable to metal-induced artifacts. For an accurate postoperative assessment of spinal instrumentation and of any complications, it is important that radiologists be familiar with the normal imaging appearances of the lumbar spine after stabilization, fusion, and disk replacement with various techniques and devices.

Plaster cast immobilisation during air travel-analysis of current practice and aircraft-simulated experimental study.

BACKGROUND: There is an increase in aircraft transportation of patients with lower limb fractures. Current practice is variable. Our aim was to study current practice and to analyse the situation in an experimental simulated aircraft flight. METHODS: Current advice supplied by commercial airline offices in the UK was noted. Postal questionnaires were sent to Orthopaedic Consultants in the UK to obtain their current practice. Experimental aircraft travel was simulated in a decompression chamber with five medically fit volunteers with no fracture, immobilised in an above knee plaster cast. Compartment pressure and venous return was documented and the results analysed in two different positions with the leg elevated and dependant. RESULTS: Airlines do not have any formal guidelines. Orthopaedic consultants in the UK note variable advise in this situation. Experimental study in the aircraft simulation showed that two volunteers developed significant increase in compartmental pressure with the leg elevated to 90 degrees , which settled after the plaster cast was split. There was no increase in compartment pressure noted with leg dependant on the floor with 45 degrees of flexion at hip. CONCLUSION: The literature on this issue is limited. With our analysis we feel that patients can be transported with the plaster cast split with limb dependant on the floor i.e. hip flexion less than 45 degrees . Our volunteers had no fractures so direct comparison with pathological changes in acute fracture is problematical. Further studies into this problem are recommended.

Measurement of fracture kyphosis with the Oxford Cobbometer: intra- and interobserver reliabilities and comparison with other techniques.

STUDY DESIGN: Statistical analysis of 3 techniques for measuring thoracolumbar kyphosis secondary to fracture. OBJECTIVES: To determine the reliability of using an Oxford Cobbometer and assess the most reliable measurement technique. SUMMARY OF BACKGROUND DATA: The reproducibility of Cobb angles for the assessment of saggital plane deformity on spine radiographs has been shown to have significant variability in both intra- and interobserver error. METHODS: Twenty-four lateral spine radiographs of patients with thoracic and lumbar vertebral fractures were measured on 2 separate occasions, in random order, by 4 blinded observers using the same Oxford Cobbometer and ruler. RESULTS: Method 2, the angle from the inferior endplate of the vertebra above the fractured vertebra to the superior endplate of the vertebra below the fractured vertebra, had the greatest intraobserver and interobserver reliabilities (rho = 0.856-0.976 and rho = 0.95, respectively). The other 2 methods had lower reliabilities; however, all 3 methods were well above the statistically acceptable threshold of >0.8, and the intraobserver reliabilities with each observer was 99% overall. These reliabilities supersede results reported previously using the conventional Cobb technique. The absolute mean difference between readings and 95% limit of agreement also improves on previous data, 2 degrees and +/- 5.8 degrees , respectively. CONCLUSIONS: Highest intraclass correlation coefficients were obtained using method 2. Using the Oxford Cobbometer to measure fracture kyphosis has higher reliability than the standard Cobb angle technique. It is easy and quick to use in a clinical setting.