A Prospective, Randomized, Multicenter Trial of the Charité Artificial Disc vs. Fusion for Single Level Lumbar Degenerative Disc Disease: Two Year Follow-up

Introduction: Short and long-term results of artificial disc replacements in the lumbar spine have been described retrospectively. We report the clinical results at two years from the first randomized controlled trial comparing an artificial disc replacement (Charité) to anterior lumbar interbody fusion (ALIF) for the treatment of lumbar degenerative disc disease (DDD) at one level.

Methods: The study was conducted following review and approval by the U.S. FDA, and each site’s IRB. Following informed consent, 304 subjects were randomized using a 2:1 randomization scheme, with 205 subjects enrolled in the Charité group (C), and 99 in the fusion group (F). The fusion group had anterior lumbar interbody fusion (ALIF) with BAK cages and iliac crest bone graft. Subjects were blinded to their randomization until after their surgery to prevent dropout. Gender was comparable between both groups (Males, C=92, F=55, Females, C=113, F=44. Mean age was the same for both groups at 39.6 years. All subjects were treated at one level, at either L4-5 (C=61, F=32) or L5-S1 (C=144, F=67) via a mini-ALIF retroperitoneal approach.

Results: Mean operative time (C=111 min, F=114 min) and perioperative blood loss (C=207 ml, F=209 ml) were equivalent. Length of hospital stay in was less in the Charité group (C=3.7 days, F=4.3 days). Clinical outcomes were determined by VAS, Oswestry (ODI), and SF-36 questionnaires (see graph). At 2 years, mean pain as determined on the VAS decreased 62.5% for the Charité group and 50.0% for the fusion group. ODI disability decreased 25.9% in the Charité group, and 23.9% in the fusion group. With respect to the SF-36, improvement was noted in both physical function (C=14.3, F=14.5 improvement) and bodily pain scores(C=13.2, F=12.6 improvement). With respect to satisfaction with the procedure, 73% (150/205) were satisfied in the Charité group compared to 55% (54/99) in the fusion group at 2 years. When subjects were asked if they would choose the same treatment again at 2 years, in the Charite group, 60% (123) responded “definitely yes” and 13.2% (27) responded “probably yes” (total yes = 83.2%) compared to 51.5% (51) and 13.1% (13) respectively, (total yes = 64.6%) in the fusion group. Aside from graft site pain in 17% of the fusion group, the complication rate was 21.4% in the Charité group, and 17.2% in the fusion group. Conclusion: Decrease in pain was greater in the Charité group and function and health status were equivalent. Patient satisfaction was higher at 2 years in the Charité group. The results of this study demonstrate that the Charité artificial disc replacement is a safe and effective alternative to fusion for one-level symptomatic lumbar DDD.

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