Long-term Outcomes of 2-Level Total Disc Replacement Using ProDisc-L: Nine- to 10-Year Follow-up

STUDY DESIGN: A prospective clinical data analysis. OBJECTIVE: To determine the long-term clinical success of 2-level total disc replacement (TDR) in patients with degenerative disc disease. SUMMARY OF BACKGROUND DATA: Early successful clinical results of 2-level TDR have been reported. Few studies exist that have described this procedure's durability in the long term. METHODS: Fifteen patients underwent 2-level lumbar TDR with the ProDisc-L as part of a randomized trial, 13 of whom were available for follow-up. The patients were assessed preoperatively and at 2 years, 5 years, and more than 9 years postoperatively using visual Oswestry Disability Index. At the last follow-up visit, 2 additional questions were asked: satisfaction with surgery and willingness to undergo the same treatment. Finally, clinical success was assessed using a previously described definition. RESULTS: Mean follow-up time was 9.6 years (range, 9.2-10.3 yr). Postoperatively there was a significant improvement in Oswestry Disability Index score from baseline (70.0 vs. 15.7 at 2 yr, P = 0.002) that remained unchanged during the period of follow-up (19.8 at 5 yr, P = 0.003 and 12.9 at 9-10 yr, P = 0.002). Ninety-two percent of patients were "satisfied" or "somewhat satisfied" with treatment and the same number would undergo treatment again. Eighty-five percent of patients achieved clinical success. CONCLUSION: This prospective study demonstrates the durable clinical success of 2-level lumbar TDR as assessed at more than 9 years postoperatively. LEVEL OF EVIDENCE: 4.