Anterior cervical fusion using dense cancellous allografts and dynamic plating

OBJECTIVE: Dense cancellous grafts provide an open matrix for vascular and cellular penetration for early osseous integration. Thus, they provide a better biological fusion substrate than cortical or corticocancellous grafts. The aim of this study is to evaluate the efficacy of the dense cancellous allografts as a substrate for anterior cervical fusion along with instrumentation. METHODS: This is a retrospective study of 98 patients who underwent anterior cervical discectomy, fusion with dense cancellous allograft bone, and instrumentation using dynamic plating between January 2001 and March 2002. Of these procedures, 60 involved single-level and 38 involved two-level fusions. Subsidence was assessed by plain x-rays at 1, 3, 6, and 12 months and fusion at 3, 6, and 12 months after surgery. Fusion was defined as the appearance of bridging trabecular bone and absence of motion in flexion-extension films. RESULTS: The mean follow-up period was 15 months (range, 12-25 mo). Successful fusion was observed in 70, 84, and 96% of the patients at 3, 6, and 12 months, respectively. The average subsidences for single-level and two-level fusions were 2.0 and 3.2 mm, respectively. No allograft- or hardware-related complications were encountered in our series. CONCLUSION: Dense cancellous allografts are very effective as bone graft substitutes for achieving anterior cervical fusion along with instrumentation. Successful fusion was observed in 70% of our patients at 3 months, with a fusion rate of 96% at 1 year. These allografts provide an effective replacement for autologous grafts in cervical interbody fusion.