Long-term results of one-level lumbar arthroplasty - Minimum 10-year follow-up of the CHARITE artificial disc in 106 patients

Study Design. A retrospective chart and radiographic review. Objectives. To determine the long-term clinical results, radiographic results, and incidence of complications in a large patient cohort with one-level lumbar total disc replacement (TDR). Summary of Background Data. Prior authors have described short-term, mid-term, and long-term clinical and radiographic results in patients with lumbar TDR with highly variable results. Methods. From January 1989 to November 1995, 108 patients, with a mean age of 36.4 years, underwent lumbar TDR with the CHARITE Artificial Disc, with 106 available for follow-up. A modified Stauffer-Coventry scale was used to determine clinical outcome. Return to work, work level, and the incidence of complications were assessed. Dynamic lateral flexion-extension and lateral bending radiographs were performed and segmental range of motion (ROM) was measured using the Cobb method. Results. Mean follow-up time was 13.2 years (range, 10 - 16.8 years). Of the 106 patients, 87 (82.1%) had either an excellent or good clinical outcome. Of the 96 patients working before surgery, 86 returned to work (89.6%), including 77.8% of patients with hard labor level employment (28 of 36) returning to the same level of work. The mean ROM in flexion-extension was 10.1 degrees, in lateral bending it was 4.4, and 90.6% of implanted prostheses were still mobile. Eight patients (7.5%) required posterior instrumented fusion. There were 5 cases (4.6%) of postoperative facet arthrosis, 3 cases (2.8%) of subsidence, 3 cases (2.8%) of adjacent-level disease, and 2 cases (1.9%) of core subluxation. Conclusions. This retrospective study demonstrates the safety and efficacy of the CHARITE Artificial Disc at one level, either L4 - L5 or L5 - S1, in the long-term. Clinical outcomes and the rate of return to work were excellent overall. The rate of adjacent-level disease requiring surgical intervention was considerably lower (2.8%) compared with reports in the literature for lumbar fusion. As with any surgical procedure, proper indications play a pivotal role in clinical success.