gms | German Medical Science

Objective: The optimal surgical management of multilevel cervical spondylotic myelopathy (MCSM) remains controversial. This retrospective analysis investigated the safety and efficacy of Invadur^®-Oxpekk^®-cage implantation and plate-screw instrumentation after anterior mono- or bilevel corpectomy and determined the clinical outcome and the rate of solid bony fusion.

Methods: Between 2006 and 2009 22 patients (age: 64.2±10.95 years) underwent cervical corpectomy, 19 patients single-level, 3 patients two-level. An offspring of the PEEK-Cage family, the Invadur^®-Oxpekk^®-cage, a polymeric innovation of polyetherketonketon, was used to replace the vertebral bodies. The cage was filled with autologous bone and a supplemental anterior plate fixation was performed. VAS-, Nurick-, European myelopathy-scores and the Neck Disability Index were used to evaluate clinical outcome. The radiographic evaluation was performed by high resolution computerized tomography (CT), and flexion-extension radiographs.

Results: Mean follow-up time was 27.2±7.5 months. The mean VAS changed from 3±3.4 to 1.6±2.3 (p<0.05). The Nurick-Score improved significantly from 8.8±1.6 to 6.9±2.3 (p<0.05). The mean European myelopathy-score showed an improvement from preoperative 13.1±1.5 to postoperative 15±2.8 (p<0.05). The neck-disability-index changed from 17±9.9 to 11±7.8 (p<0.05). Complete bony fusion could be demonstrated on CT in all except one patient. Slight bony resorption around screws was found in 3 patients although a complete bony athrodesis was seen, too. Flexion-extension X-rays demonstrated no pathological movement in any of the cases. Telescoping of the cage into the adjacent vertebra accompanied by secondary screw loosening occurred in one patient and needed resurgery. There was no correlation between clinical and radiological outcome.

Conclusions: Vertebral body replacement with Invadur^®-Oxpekk^®-cage and plate-screw-osteosynthesis seems to be a valuable alternative to the gold standard autologous bone graft and plating. Costs are lower compared to expandable titanium implants. Surgical sequelae from harvesting iliac bone grafts are avoided. The clinical outcome is comparable to previous studies and radiological results show a stable construct in all patients. Bony fusion and thus solid athrodesis can be achieved in a comparable rate as with iliac crest replacement after corpectomy.