188 - Seven-year Clinical Results of Cervical Total Disc Replacement Compare...

General Session: Cervical Degenerative

Presented by: K. Radcliff - View Audio/Video Presentation (Members Only)


K. Radcliff(1), R. Davis(2), M. Hisey(3), P. Nunley(4), G. Hoffman(5), R. Jackson(6), H. Bae(7), T. Albert(8), D. Coric(9), K. Kim(10)

(1) NYU Hospital for Joint Diseases, Orthopaedic Surgery, New York, NY, United States
(2) SUNY Downstate, Orthopaedic Surgery, Brooklyn, NY, United States


Introduction: The objective of this study was to report the outcome of a prospective, randomized, FDA IDE trial of TDR versus anterior discectomy and fusion for the treatment of two-level disc disease.

Methods: Prospective, randomized, multicenter, concurrently controlled FDA clinical trial conducted across 24 sites in the US. The patient population consisted of 330 patients randomized in a 2:1 ratio to receive TDR (225 patients) or ACDF (105 patients). Inclusion criteria included a diagnosis of symptomatic cervical degenerative disc disease at two contiguous levels and no history of previous operations on the cervical spine. TDR patients were treated using a Mobi-C© artificial disc (Zimmer Biomet, Austin TX, USA). ACDF with allograft and plate was used as a control treatment. Outcome measures were collected through 84 months. The primary endpoint was an FDA composite definition of success comprising clinical improvement and an absence of secondary surgery events.

Results: At 7 years, data was available for 172 TDR patients and 63 ACDF patients. Follow-up at 84 months was 84.4% for TDR and 75.0% for ACDF. The overall success rates of TDR and ACDF patients were 60.8% and 34.2%, respectively (p< 0.0001). Both the TDR and ACDF group showed significant improvement from baseline NDI scores, VAS neck and arm pain scores, and SF-12 MCS/PCS scores (p< 0.0001). Overall, most patients (81% TDR, 70% ACDF) had improved NDIcompared to baseline and only a small percentage of patients had worse NDI (3.8% ACDF and 2.5% TDR, p>0.05). Similarly, only a small number of patients (5% TDR, 6.8% ACDF) had worse neck pain after surgery. Overall, TDR had consistently better outcomes across all postoperative periods. The overall success analysis demonstrated superiority of TDR over ACDF at 7 years. At 7 years, the mean improvement from baseline NDI scores was higher in the TDR group compared to the ACDF group (TDR: 35.6±20.3 vs. ACDF: 28.2±21.7). The NDI success rate was also significantly greater in the TDR group (TDR: 79.0% vs. ACDF: 58.0%; p=0.001). Mean improvement in VAS neck pain score was 50.9±30.6 for the TDR patients and 44.1±33.9 for the ACDF patients. TDR patients had a mean improvement in SF-12 scores of 10.5±12.7 (MCS) and 12.7±10.9 (PCS) while the ACDF group had a mean improvement of 7.2±14.3 (MCS) and 10.3±11.4 (PCS). Mean segmental ROM was maintained in the TDR group. The TDR group had a significantly higher rate of patients who were “very satisfied” with their treatment compared to the ACDF group (TDR: 85.9% vs. ACDF: 73.9%). The subsequent surgery at the index level was significantly lower for the TDR group compared to the ACDF group (TDR: 4.4% vs. ACDF: 16.2%; p=0.001). The 7-year rate of adverse events was 5.3% for TDR patients and 8.6% for ACDF patients.

Discussion: Overall, at 7 years, cervical spine surgery in properly selected patients is remarkably beneficial. TDR continues to show superiority over ACDF for overall success rates. The TDR treated group outperformed the ACDF control group in pain metrics, patient satisfaction, and subsequent surgery rates. Two-level TDR appears remains a safe and effective treatment option for the treatment of symptomatic degenerative disc disease through 7 years.