Prospective randomized study of the Charite artificial disc: data from two investigational centers.

Background Context: For decades there has been a desire to restore motion of a painful degenerated spinal segment. Artificial discs have been used in Europe for almost 20 years. In the few reports available in the literature, the results have been promising. However, there have been no prospective randomized studies comparing artificial discs with spinal fusion.

Purpose: The purpose of this study was to determine if patients with symptomatic degenerative disc disease treated with Charite artificial disc (DePuy Spine, Raynham, MA) arthroplasty would show significant improvement in functional outcome measures and to compare these results to fusion.

Study Design/setting: This was a prospective randomized clinical trial comparing total disc replacement with anterior lumbar interbody fusion using cages. The data reported were collected from two spine specialty centers participating in a Food and Drug Administration regulated trial.

Methods: A consecutive series of 144 patients were randomized using a 2:1 ratio of Charite versus BAK (Zimmer Spine, Minneapolis, MN). All patients were being treated for single-level discogenic pain confirmed by plain radiography, magnetic resonance imaging and provocative discography. Data were collected at designated follow-up periods for up to 24 months.

Results: The mean age was 40.1 years (range, 21 to 56 years). Forty-four cases had BAK anterior interbody fusion, and 100 cases were randomized to Charite disc replacement. The mean operating time was 76.2 minutes (range, 54 to 137 minutes) for the Charite cases. The mean estimated blood loss was 196.2 cc (range, 50 to 1,800 cc). Most patients were discharged in 1 to 2 days with a soft corset and returned to normal activities within 3 weeks if they underwent the disc replacement. The mean Oswestry Disability Index score for the BAK group was 69.6+/-12.8 preoperatively and 27.5+/-26.4 at 24-month follow-up (p<.001) The corresponding mean Oswestry score for the Charite disc patients was 70.9 preoperatively and 30.0 at 24-month follow-up (p<.001).

Conclusions: In this prospective randomized study, both surgical groups improved significantly. Complications of total disc replacement were similar to those encountered with anterior lumbar interbody fusion. Total disc replacement appears to be a viable alternative to fusion for the treatment of single-level symptomatic disc degeneration unresponsive to nonoperative management.