A prospective, randomized, multicenter food and drug administration Investigational device exemptions study of lumbar total disc replacement with the CHARITE™ artificial disc versus lumbar fusion Part I:: Evaluation of clinical outcomes

Study Design. A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial. Objectives. The purpose of this study was to compare the safety and effectiveness of lumbar total disc replacement, using the CHARITE (TM) artificial disc (DePuy Spine, Raynham, MA), with anterior lumbar interbody fusion, for the treatment of single-level degenerative disc disease from L4-S1 unresponsive to nonoperative treatment. Summary of Background Data. Reported results of lumbar total disc replacement have been favorable, but studies have been limited to retrospective case series and/or small sample sizes. Methods. Three hundred four ( 304) patients were enrolled in the study at 14 centers across the United States and randomized in a 2: 1 ratio to treatment with the CHARITE (TM) artificial disc or the control group, instrumented anterior lumbar interbody fusion. Data were collected pre- and perioperatively at 6 weeks and at 3, 6, 12, and 24 months following surgery. The key clinical outcome measures were a Visual Analog Scale assessing back pain, the Oswestry Disability Index questionnaire, and the SF-36 Health Survey. Results. Patients in both groups improved significantly following surgery. Patients in the CHARITE (TM) artificial disc group recovered faster than patients in the control group. Patients in the CHARITE (TM) artificial disc group had lower levels of disability at every time interval from 6 weeks to 24 months, compared with the control group, with statistically lower pain and disability scores at all but the 24 month follow-up ( P < 0.05). At the 24-month follow-up period, a significantly greater percentage of patients in the CHARITE (TM) artificial disc group expressed satisfaction with their treatment and would have the same treatment again, compared with the fusion group (P < 0.05). The hospital stay was significantly shorter in the CHARITE (TM) artificial disc group (P < 0.05). The complication rate was similar between both groups. Conclusions. This prospective, randomized, multicenter study demonstrated that quantitative clinical outcome measures following lumbar total disc replacement with the CHARITE (TM) artificial disc are at least equivalent to clinical outcomes with anterior lumbar interbody fusion. These results support earlier reports in the literature that total disc replacement with the CHARITE (TM) artificial disc is a safe and effective alternative to fusion for the surgical treatment of symptomatic disc degeneration in properly indicated patients. The CHARITE (TM) artificial disc group demonstrated statistically significant superiority in two major economic areas, a 1-day shorter hospitalization, and a lower rate of reoperations (5.4% compared with 9.1%). At 24 months, the investigational group had a significantly higher rate of satisfaction (73.7%) than the 53.1% rate of satisfaction in the control group ( P = 0.0011). This prospective randomized multicenter study also demonstrated an increase in employment of 9.1% in the investigational group and 7.2% in the control group.