Four-year results of a prospective single-arm study on 200 semi-constrained total cervical disc prostheses: clinical and radiographic outcome.

OBJECTIVE Recent studies have described encouraging outcomes after cervical total disc replacement (cTDR), but there are also critical debates regarding the long-term effects of heterotopic ossification (HO) and the prevalence of adjacent-level degeneration. The aim in this paper was to provide 4-year clinical and radiographic outcome results on the activ C disc prosthesis. METHODS A total of 200 subjects underwent single-level activ C (Aesculap AG) implantation between C-3 and C-7 for the treatment of symptomatic degenerative disc disease. Clinical and radiographic assessments were performed preoperatively, intraoperatively, at discharge, and again at 6 weeks, 6 months, 1 year, 2 years, and 4 years. Radiographic evaluations were done by an independent core laboratory using a specific software for quantitative motion analysis. RESULTS Neck Disability Index (NDI) and visual analog scale (VAS) score for neck and arm pain decreased significantly from baseline to the 4-year follow-up. The mean improvement for NDI was 20, for VAS severity and frequency of neck pain 26.4 and 28, and for VAS severity and frequency of arm pain 30.7 and 35.1, respectively. The neurological situation improved for the majority of patients (86.4%); 76.1% of cases were asymptomatic. Subsequent surgical interventions were reported in 7% of the cases, including device removals in 3%. In 2.5% a subsidence greater than 3 mm was recorded; 1 of these cases also had a migration greater than 3 mm. No device displacement, expulsion, disassembly, loose or fractured device, osteolysis, or facet joint degeneration at the index level was observed. Segmental lordotic alignment changed from -2.4° preoperatively to -6.2° at 4 years, and postoperative height was maintained during the follow-up. Advanced HO (Grade III and IV) was present in 27.1% of the cases; 82.4% showed segmental mobility. A progression of radiographic adjacent-segment degeneration occurred in 28.2%, but only 4.5% required surgical treatment. CONCLUSIONS The activ C is a safe and effective device for cervical disc replacement confirming the encouraging results after cTDR. Clinical trial registration no.: NCT02492724 ( clinicaltrials.gov ).

Incidence of vascular complications arising from anterior spinal surgery in the thoraco-lumbar spine.

STUDY DESIGN: Modern biomaterials and instrumentation have popularised surgery of the thoraco-lumbar spine through an anterior route. The advantage of anterior surgery is that it allows for a direct decompression of the compromised spinal canal. However, the potential for devastating long-term sequelae as a result of complications is high. PURPOSE: The aim of this study was to give a general overview and identify the incidence of vascular complications. OVERVIEW OF LITERATURE: There is limited literature describing the overall incidence and complications of anterior spinal surgery. METHODS: A retrospective review of a prospective database of 1,262 consecutive patients with anterior surgery over a twelve-year period. RESULTS: In our study, 1.58% (n=20) of patients suffered complications. Injury to a major vessel was encountered in 14 (1.11%) cases, of which nine involved an injury to the common iliac vein. In six cases, the original procedure was abandoned due to a life-threatening vascular injury (n=3) and unfavourable anatomy (n=3). CONCLUSIONS: The incidence of vascular and other complications in our study was relatively low. Nevertheless, the potential for devastating long-term sequelae as a result of complications remains high. A thorough knowledge and awareness of normal and abnormal anatomy should be gained before attempting such a procedure, and a vascular surgical assistance especially should be readily accessible. We believe use of access surgeons is mandatory in cases with difficult or aberrant anatomy.

Total spondylectomy of C2: report of three cases and review of the literature.

STUDY DESIGN: A report on 3 patients undergoing total spondylectomy of the C2 vertebra for tumor and the technique for C1-3 reconstruction. OBJECTIVE: To illustrate the feasibility of complete resection of the C2 vertebra with preservation of the vertebral arteries and cervical nerve roots. BACKGROUND: Total spondylectomy provides improved progression free survival in many patients with locally aggressive spinal tumors. However, the perceived technical demands of effectively preserving both vertebral arteries, maintaining cervical nerve roots, and biomechanical reconstruction of the cranial-cervical junction often dissuades surgeons from carrying out total spondylectomy of the C2 vertebra. METHODS: A review of 3 patients undergoing total C2 spondylectomy for tumor (thyroid adenocarcinoma, chordoma, and solitary plasmocytoma) was done. The surgical procedure that was undertaken and the technique used are described. RESULTS: Postoperatively, all 3 patients had uneventful postoperative recovery with gradual improvement in their neurologic functions. CONCLUSION: Preservation of bilateral vertebral arteries and all cervical nerve roots is feasible when carrying out intralesional total spondylectomy in patients with C2 vertebral body tumors and should be considered in patients thought to benefit from total C2 vertebra excision. In an attempt to augment construct stability and provide anterior column load sharing, we have used mesh cage and iliac crest graft between C1 and C3 held in place with a short cervical plate without complications.

Atlantoaxial fixation using the polyaxial screw-rod system.

The aim of this study is to evaluate the first results of the atlantoaxial fixation using polyaxial screw-rod system. Twenty-eight patients followed-up 12-29 months (average 17.1 months) were included in this study. The average age was 59.5 years (range 23-89 years). The atlantoaxial fusion was employed in 20 patients for an acute injury to the upper cervical spine, in 1 patient with rheumatoid arthritis for atlantoaxial vertical instability, in 1 patient for C1-C2 osteoarthritis, in 2 patients for malunion of the fractured dens. Temporary fixation was applied in two patients for type III displaced fractures of the dens and in two patients for the atlantoaxial rotatory dislocation. Retrospectively, we evaluated operative time, intraoperative bleeding and the interval of X-ray exposure. The resulting condition was subjectively evaluated by patients. We evaluated also the placement, direction and length of the screws. Fusion or stability in the temporary fixation was evaluated on radiographs taken at 3, 6, 12 weeks and 6 and 12 months after the surgery. As concerns complications, intraoperatively we monitored injury of the nerve structures and the vertebral artery. Monitoring of postoperative complications was focused on delayed healing of the wound, breaking or loosening of screws and development of malunion. Operative time ranged from 35 to 155 min, (average 83 min). Intraoperative blood loss ranged from 50 to 1,500 ml (average 540 ml). The image intensifier was used for a period of 24 s to 2 min 36 s (average 1 min 6 s). Within the postoperative evaluation, four patients complained of paresthesia in the region innervated by the greater occipital nerve. A total of 56 screws were inserted into C1, their length ranged from 26 to 34 mm (average, 30.8 mm). All screws were positioned correctly in the C1 lateral mass. Another 56 screws were inserted into C2. Their length ranged from 28 to 36 mm (average 31.4 mm). Three screws were malpositioned: one screw perforated the spinal canal and two screws protruded into the vertebral artery canal. C1-C2 stability was achieved in all patients 12 weeks after the surgery. No clinically manifested injury of the vertebral artery or nerve structures was observed in any of these cases. As for postoperative complications, we recorded wound dehiscence in one patient. The Harms C1-C2 fixation is a very effective method of stabilizing the atlantoaxial complex. The possibility of a temporary fixation without damage to the atlantoaxial joints and of reduction after the screws and rods had been inserted is quite unique.