European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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Many new interbody fusion cages have been recently developed, but clinical studies analyzing fusion outcome are still scarce. Radiological methods to assess fusion are not standardized and are often unreliable. Cages have been stated to provide good segmental distraction, provide axial load support and reduce segmental mobility, but there have been reports of failed fusions because of implant failure. ⋯ In the absence of gross segmental instability, micromotion at the host graft interface may still exist. As a result, fusion will never occur, instead a pseudoarthrosis will develop. For monitoring fusion, the use of non-metallic cages has distinct advantages, because no metal artifacts will disturb radiological assessment.
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Less invasiveness is the way forward for spinal surgery. Minimal disruption of tissue, preservation of muscle function, and restoration of normal spinal alignment are still the goals of most surgical procedures. ⋯ The autograft is harvested from the vertebral body, thus avoiding the morbidity associated with an iliac crest bone graft. The operative steps for the procedure are described.
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Clinical Trial
A new approach to computer-aided spine surgery: fluoroscopy-based surgical navigation.
A new computer-based navigation system for spinal surgery has been designed. This was achieved by combining intraoperative fluoroscopy-based imaging using conventional C-arm technology with free-hand surgical navigation principles. Modules were developed to automate digital X-ray image registration. ⋯ Stereotactic instruments and graphical user interfaces for image-interactive transpedicular screw insertion have been developed. A detailed validation of the system was performed in the laboratory setting and throughout an early clinical trial including eight patients in two spine centers. Based on the resulting data, the new technique promises improved accuracy and safety in open and percutaneous spinal surgery.
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Comparative Study
Odontoid fractures: high complication rate associated with anterior screw fixation in the elderly.
This study is a retrospective analysis of patients older than 65 years with odontoid fractures. The series consisted of 29 consecutive patients with odontoid fractures (18 women, mean age 78, range 66-99 years). Twenty-six patients were neurologically intact, Frankel E, whereas three had neurological symptoms: two Frankel D and one Frankel C. ⋯ We conclude that anterior screw fixation according to Böhler is associated with an unacceptably high rate of problems in the elderly. Probable causes may be osteoporosis with comminution at the fracture site, or stiffness of the cervical spine preventing ideal positioning of the screws. As non-operative treatment also often fails, the method of choice seems to be posterior C1-C2 fusion.
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Comparative Study
Nucleus pulposus inhibits the axonal outgrowth of cultured dorsal root ganglion cells.
Although it is well established that nucleus pulposus cells may induce structural and functional changes in adjacent nerve roots when placed epidurally, it is not known whether this is due to direct neurotoxic effects or whether the nerve roots are affected indirectly by reduction of nutrition and inflammatory/immunologic mechanisms. In the present study we assessed the effects of various tissues on cultured dorsal root ganglions from newborn rats. ⋯ The study thus showed that there are direct axonotoxic effects induced by the nucleus pulposus, and since frozen nucleus pulposus did not have any effects, it may be assumed that the mechanisms are related to substances produced by the nucleus pulposus cells. The presented model allows for future studies on the neurotoxic properties of nucleus pulposus cell-derived candidate substances.