14 systems for anterior cervical stabilisation were evaluate under flexion-compression bending using test procedures conforming to Static and Fatigue Test Methods for Spinal Implant Assemblies using Corpectomy Models Part 2a [ISO/TC 150/SC5 N127C] Plates of standardised active length were tested in an in-vitro model of a single corpectomy of the lower cervical spine using composite test blocks manufactured by Sawbones to have physical properties similar to cervical vertebrae. Results reveal a wide range in final yield strengths with bi-cortical systems significantly stronger than uni-cortical ones. There was a fourfold difference in ultimate load between the stronger and weakest systems. We found that mode of failure was influenced by plate thickness, screw length and screw placement.
The purpose of this retrospective study was to analyze the indications for spinal instrumentation, report the clinical features, operative details and outcome in 16 patients with active pyogenic spinal infection. Between January 1991 to October 1999, 81 patients with spontaneous pyogenic spinal infection were treated at the authors’ institution. Surgery (other than biopsy) was indicated in 24 patients for neurological deterioration, deformity or instability. Sixteen of these patients were treated with instrumentation in the presence of active spinal infection. Six patients underwent combined anterior and posterior procedures. 10 had a posterior procedure only. Outcomes assessed were control of infection, neurology, fusion, back pain and complications. At a mean follow up period of 26. 9 months, all surviving patients were free of clinical infection. None of the patients had neurological deterioration. All patients who had neurological deficit preoperatively improved by at least one Frankel grade. A solid fusion was achieved in 15 patients. 12/15 patients remained asymptomatic or had very little pain. The remaining 3 patients had mild to moderate back pain. The mean correction of the kyphotic deformity was 18. 92 degrees. Postoperative complications included bronchopneumonia, nonfatal pulmonary embolism and seizures in 3 patients. One patient developed progressive kyphosis despite instrumentation but eventually fused in kyphus. Given early recognition of pyogenic spinal infection, most cases can be managed non-operatively. Our results support that instrumented fusion with or without decompression may be used safely when indicated without the risk of recurrence of infection. Instrumentation facilitates nursing care and allows early mobilisation. For biomechanical reasons, a combined procedure is probably indicated for lesions above the conus. For lesions below the conus, we were able to achieve successful results with posterior approach only.
In the 40 years since Smith and Robinson described the anterior approach to decompress and fuse the cervical spine, generally acceptable clinical results have been reported though few papers include any form of detailed outcome assessment. More recently Snyder and Bernhardt have described an anterolateral disc-preserving approach to treat cervical radiculopathy that does not entail vertebral artery exposure. We describe our experience of this procedure. Surgery was performed on 40 patients ( 21 male, 19 female, mean age 41 years). Functional outcome was assessed by the Neck Disability Index (NDI), return to usual work status, patient subjective satisfaction rating, and by standard VAS. Radiographic evaluation was performed looking at the following parameters: neutral films – maintenance of interbody disc height/diameter ratio R and degree of kyphosis/lordosis: dynamic films – degree of movement maintained at operated motion segment. At an average follow up of 20 months(range 6 – 36) the mean NDI had fallen from 45% to 10% .Mean neck pain score was 2 (pre op was 7), average arm pain score 1 (pre op was7). 93% of patients had returned to work, 85% to their original occupation at an average of 11 weeks. Patient satisfaction scores were: 85% very satisfied, 5 % satisfied, 5% unsatisfied and 5% very unsatisfied. Radiologically it was possible to preserve intervertebral body disc height and motion in some patients whilst others lost some height and motion. A minority fused spontaneously. ACFID is associated with clinical functional outcome scores comparable with those reported in the literature for alternative procedures. Bone graft donor site morbidity is avoided and radiological results show that preservation of useful motion at the operated disc is possible.
death data for further patients currently awaited from Cancer Registry.
The Synex cage is an expanding titanium implant designed for reconstruction of the anterior column in injury, post-traumatic kyphosis or tumour of the thoracolumbar spine. It is supplemented by a stabilizing implant. As it is expandable in situ it therefore can be inserted via a relatively small exposure. The design enables good purchase of the endplates and reduces the possibility of secondary displacement. Surgery for anterior reconstruction is usually performed via an anterior approach, however, there are incidences were a posterolateral approach is indicated. The Synex cage is useful in these circumstances, as being expandable, posterolateral insertion with preservation of the nerve roots is possible. The Synex cage is then supplemented with a posterior construct. The cage can be inserted via a left or right posterolateral approach. A specially designed angled screwdriver is now available to release the ratchet mechanism and if necessary collapse the cage. We present, what is, to the best of our knowledge and that of the manufacturer, the first two patients where a Synex cage has been inserted using the posterolateral approach.