Freeze-dried fibular allograft in anterior spinal surgery: cervical and lumbar applications

Fifty-six patients who underwent anterior fusion utilizing fibular allograft are reviewed. Thirty-two patients underwent multiple-level anterior cervical discectomy and fusion utilizing fibular strut allograft, and 24 underwent anterior lumbar discectomy and fusion using fibular strut allograft. Cervical surgery was performed via the strut technique of Whitecloud and LaRocca and lumbar surgery was performed via a transperitoneal or retroperitoneal approach. Postoperatively, patients were assigned a clinical grade based on symptomatic relief and medication usage. X-rays were visually inspected, and quantitatively digitized for Cobb angle and translation in order to assess the status of arthrodesis. In the cervical group, the rate of clinical success (87.5%) exceeded the arthrodesis rate. By inspection, 65% fused, at a mean time of 23.5 months postoperatively. In the lumbar group, the overall clinical success rate was 68%. This correlated quite strongly with a fusion rate of 58%. Smoking was a negative correlate with arthrodesis. Patients receiving Workers' Compensation were also more likely to have an unsatisfactory clinical outcome. The results of this study highlight the difference between anterior arthrodesis in the cervical and lumbar spine. The biomechanical stability afforded by the fibular strut in the cervical spine appears to outweigh the disadvantages of delayed time to union. The rate of posterior cervical fusion to salvage symptomatic pseudoarthrosis was quite low (9.3%), thus suggesting that additional posterior surgery in this particular group of patients should not be considered for a minimum of two years postoperatively. In the lumbar group, status of arthrodesis correlated closely with clinical outcome. Fusion rate in this group was disappointing, corresponding to other reports in the literature. Based on these data, primary anterior body fusion without allograft in the lumbar spine cannot be recommended, as a viable alternative to conventional autograft.