704 Prospective, Randomized, Multicenter Trial of Artificial Disc versus Fusion for Single-level Lumbar Degenerative Disc Disease: A 2-year Follow-up Investigational Device Exemption Study

Abstract

INTRODUCTION: Prior reports of artificial disc replacements in the lumbar spine have been described retrospectively. We report the first results from a randomized controlled trial of the Charité artificial disc replacement versus fusion for the treatment of lumbar degenerative disc diseaseat one level. METHODS: The study was conducted after review and approval by the United States Food and Drug Administration and each site’s institutional review board. All enrolled subjects had failed at least 6 months of nonoperative management and were being treated for single-level symptomatic disc degeneration verified by radiographic diagnostic studies, including discography. After informed consent, 304 subjects from 15 centers were randomized using a 2:1 randomization scheme, with 205 subjects enrolled in the Charité group (C) and 99 in the Fusion group (F) who had anterior lumbar interbody fusion (ALIF) with Bagby and Kuslich (BAK) cages and autograft. Demographics were statistically similar (except for weight) between groups. All subjects were treated at one level, at either L4–L5 (C = 61, F = 32) or L5–S1 (C = 144, F = 67) via a mini-ALIF retroperitoneal approach. Clinical outcomes were determined by visual analog score (VAS), Oswestry (ODI), Short-Form 36 questionnaires, and subject satisfaction. RESULTS: Mean operative time (C = 111 min, F = 114 min) and perioperative blood loss (C = 207 ml, F = 209 ml) were equivalent. The length of hospital stay was significantly less in the Charité group (3.7 versus 4.3 d) compared with the Fusion group. The VAS and ODI scores improved significantly in both groups, with the Charité group experiencing significantly greater improvement than the Fusion group at all time points but the 24-month follow-up. Subject satisfaction was significantly higher in the Charité group (C = 77%, F = 59%). Aside from graft site pain in 17% of the fusion group, the complication rates were similar for both groups. CONCLUSION: The results of this prospective, randomized study supports the proposition that Charité artificial disc replacement is a safe and effective alternative to fusion for one-level symptomatic lumbar disc disease in appropriately selected patients.