General Session: Cervical Motion Preservation

Presented by: R. Guyer - View Audio/Video Presentation (Members Only)

Author(s):

R. Guyer(1), J. Zigler(1), D. Ohnmeiss(2)

(1) Texas Back Institute, Plano, TX, United States
(2) Texas Back Institute Research Foundation, Plano, TX, United States

Abstract

Introduction: To date, there have been several prospective studies evaluating lumbar total disc replacement (TDR) with up to 5-year follow-up reporting stable outcomes from early pre-operative visits. Longer follow-up is desirable. The purpose of this study was to evaluate the outcomes of patients enrolled in the FDA-regulated trial evaluating the safety and efficacy of a lumbar total disc replacement 10 years after the study surgery.

Methods: This was an additional follow-up evaluation made at least 10 years after surgery of patients enrolled at one site participating in the prospective FDA-regulated trial for ProDisc-L. Records for the original study were reviewed and 129 patients were identified who were enrolled in the prospective randomized trial (TDR n=34 vs. combined anterior/posterior fusion n=17) or in the continued access study arm (all received TDR n=78). After receiving IRB approval, questionnaires patterned after those used for the original study were mailed to patients. After two mailings, telephone contact was attempted. Online search services and other records were used to try to get current addresses when needed. Data have been received for 58 patients and 5 others are deceased (none related to study treatment). Outcome measures included a modified Oswestry Disability Index (ODI), visual analog scale (VAS) assessing pain, and any subsequent lumbar spine surgery.

Results: Self-reported outcomes data were analyzed for patients for whom minimum 10 year follow-up was available, thus making comparisons to earlier time periods more relevant. Outcomes achieved as early as 6 weeks to 3 month follow-up were maintained throughout 10 year follow-up. For example, the mean VAS pain scores were approximate 7.0 in the TDR and fusion groups prior to surgery, improved significantly to approximately 2.8 at 3 months postoperative, and were less than 2.8 at 10-year follow-up in both groups. ODI scores followed a similar pattern with sustained improvement in both treatment groups throughout follow-up with preoperative mean scores of approximately 60 in both groups and mean scores of less than 25 at 10-year follow-up. More than 80% of the TDR and fusion groups had a minimum 15 point improvement in their ODI scores when comparing preoperative to the 10 year follow-up scores. None of the 5 fusion patients and 12 of the TDR patients for whom 10 year follow-up was available underwent reoperation. Five of these occurred later than 5 years after the index surgery and were primarily for symptomatic adjacent segment degeneration.

Discussion: These results indicate that outcomes for this subset of patients for whom minimum 10 year follow-up could be collected remained stable from early postoperative scores. Significant improvements in mean scores noted within 3 months of surgery were maintained through 10 years. Of note, there were no indications of mechanical device failure during this long-term follow-up such as procedures to remove the devices and/or stabilize the TDR level. The clinical outcomes in this study parallel those from European studies with follow-up of 10 or more years after TDR.