Introduction: Two total disc replacement devices have been used in Europe for more than 10 years. However, there are few, if any, prospective studies evaluating their results. The purpose of this prospective study using standardized outcome evaluations was to evaluate surgical outcome following implantation of an artificial disc.

Methods: This study is based on the consecutive series of the first 57 patients undergoing total disc replacement using the SB Charité (Link) disc prosthesis. Indications included single-level symptomatic disc degeneration, failure of at least 6 months of non-operative treatment including active rehabilitation, and no previous surgery at the operated segment. Data were collected prospectively pre-operatively and at 6 weeks, 3, 6, and 12 months post-operatively (24 month follow-up data collection is continuing). Primary outcome measures included visual analog scales (VAS) assessing pain and the Oswestry Low Back Pain Disability Questionnaire.

Results: The mean operative time was 78.5 minutes and the mean estimated operative blood loss was 134.3 cc. Estimated blood loss and operating time were both significantly less for disc replacements at the L5-S1 level than at L4–5 (p< 0.05; t-test). As seen in Figures 1 and 2, there was a significant improvement in the VAS and Oswestry scores (p< 0.05) at the 6-week follow-up visit, and the improvements were maintained during subsequent follow-up visits.

There were no cases of device failure, displacement, or migration. Complications were comparable to those encountered with anterior interbody fusion.

Discussion: The results of this prospective study, using patient self-report questionnaires, demonstrated significant improvement at 6 weeks and the improvement was maintained during the 12 month follow-up period (24-month data is being collected). The disc prosthesis can be implanted safely, with complications similar to those encountered with anterior lumbar interbody fusion.