The success of anterior cervical arthrodesis adjacent to a previous fusion

Study Design. A retrospective review of all patients surgically treated for adjacent segment disease of the cervical spine over a 20-year period. Objectives. To determine the clinical and radiographic success of discectomy with interbody grafting and corpectomy with strut grafting in the treatment of adjacent segment disease of the cervical spine. Summary of Background Data. Up to 25% of all patients undergoing anterior cervical fusion have new disease due to degeneration of an adjacent segment within 10 years. The success of surgical treatment in these patients with adjacent segment disease has not been reported. Methods. Thirty-eight patients were surgically treated for adjacent segment disease by discectomy with interbody grafting or corpectomy with strut grafting. Arthrodesis was evaluated by flexion-extension lateral radiographs and clinical outcomes were assessed using Robinson's criteria at least 2 years after surgery. Fusion rates were compared by Fisher's exact test, and outcomes were compared by rank-sum analysis. Results. The rate of arthrodesis was significantly lower in the 24 patients treated by discectomy with interbody grafting at one or more levels (63%) than in the 14 patients treated by corpectomy with strut grafting (100%; P = 0.01). Clinical outcomes were similar for the corpectomy and discectomy groups (P = 0.55). There was a trend toward better outcomes in patients who achieved a solid arthrodesis (P = 0.13). Conclusions. Achieving fusion is more difficult when anterior cervical arthrodesis is performed adjacent to a prior fusion. Strut grafting resulted in a significantly higher rate of arthrodesis than interbody grafting.