Intermediate clinical outcome of Bryan Cervical Disc replacement for degenerative disk disease and its effect on adjacent segment disks.

The purpose of this study was to determine the intermediate clinical and radiographic outcomes of Bryan Cervical Disc (Medtronic Sofamor Danek, Inc, Memphis, Tennessee) replacement for the treatment of cervical degenerative disk disease and its effect on adjacent levels. Between November 2004 and December 2007, thirty-four patients (38 disks) underwent Bryan Cervical Disc replacement in the authors' hospital. The authors retrospectively analyzed the records of 32 patients who completed follow-up. Outcome data were collected preoperatively; at 3, 12, 24 months postoperatively; and at last follow-up, which ranged from 32 to 69 months (average, 49.4 months). Clinical outcome, radiographic outcome, adjacent segment degeneration, complications, and reoperations were evaluated. The SF-36 physical component, SF-36 mental component, Neck Disability Index, Japanese Orthopaedic Association score, and neck/arm pain visual analog pain scale scores were all improved significantly at each postoperative time point compared with preoperative values (P<.05), but no statistically significant differences were noted between postoperative time points (P>.05). The postoperative flexion-extension range of motion of the operative site and adjacent segments were not significantly different from the preoperative values (P>.05) and were approximately the same for each postoperative time point (P>.05). A new degeneration scoring system demonstrated that approximately 23% of the adjacent levels displayed mild degeneration at last follow-up. However, degeneration did not affect the clinical outcomes. Prosthesis-related complications were rare, and no reoperations were performed. Bryan Cervical Disc replacement achieves satisfactory mid-term clinical and radiographic outcomes. The authors observed the progression of adjacent segment degeneration postoperatively, although no degradation of clinical outcomes occurred.