Surgical management of symptomatic lumbar degenerative disc disease (DDD) currently consists of fusion or implantation of a first generation total disc replacement (TDR). This study is the first to evaluate an elastomeric one-piece TDR in a 50-patient European study.

Fifty patients with single-level, symptomatic lumbar DDD at L4-S1 who were unresponsive to at least 6-months of non-operative therapy were enrolled in a clinical trial of a viscoelastic TDR (VTDR) at three European sites. Patients were assessed clinically and radiographically at 6 weeks, 3 and 6 months, and 1 and 2 years. Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) were used to assess clinical outcomes.

Twenty-eight males and twenty-two females were enrolled in the study. The average age of patients was 39.7 (23 to 61). The operative level was L4/L5 in 13 patients and L5/S1 in 37 patients. There were no intra-operative complications. Quantitative radiographic assessment indicates that the VTDR restores and maintains a physiologically appropriate disc height and angle, while providing range of motion and translation similar to those provided by the natural disc. Mean ODI scores decreased from 48% pre-operatively to 25% at two years follow up. Mean VAS low back pain scores decreased from 7.1 cm pre-op to 3 cm at two years. Median scores indicate that half of the patient population has ODI scores below 13% and VAS back pain scores below 0.5 cm. Clinically and radiologically, this elastomeric disc is performing satisfactorily, and the causes of clinical failures can be more readily identified.