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Multi-center, Prospective, Randomized, Controlled Investigational Device Exemption Clinical Trial Comparing Mobi‑C Cervical Artificial Disc to Anterior Discectomy and Fusion in the Treatment of Symptomatic Degenerative Disc Disease in the Cervical Spine

Michael S. Hisey, MD,1 Hyun W. Bae, MD,2 Reginald Davis, MD,3 Steven Gaede, MD,4 Greg Hoffman, MD,5 Kee Kim, MD,6 Pierce D. Nunley, MD,7 Daniel Peterson, MD,8 Ralph Rashbaum, MD,9 John Stokes, MD8

1Texas Back Institute, Denton, TX; 2The Spine Institute at St. John’s Health Center, Santa Monica, CA; 3GBMC Healthcare Greater Baltimore Neurosurgical Associates, Baltimore MD; 4Oklahoma Spine & Brain Institute, Tulsa, OK; 5Orthopedic North East, Fort Wayne, IN; 6University of California Davis Medical Center, Sacramento, CA; 7Spine Institute of Louisiana, Shreveport, LA; 8Neurological Specialists of Austin, Austin, TX; 9Texas Back Institute, Plano, TX



Anterior cervical discectomy and fusion (ACDF) is the gold standard for treating symptomatic cervical disc degeneration. Cervical total disc replacements (TDRs) have emerged as an alternative for some patients. The purpose of this study was to evaluate the safety and effectiveness of a new TDR device compared with ACDF for treating single-level cervical disc degeneration.


This was a prospective, randomized, controlled, multicenter Food and Drug Administration (FDA) regulated Investigational Device Exemption (IDE) study. A total of 245 patients were treated (164 TDR: 81 ACDF). The primary outcome measure was overall success based on improvement in Neck Disability Index (NDI), no subsequent surgical interventions, and no adverse events (AEs) classified as major complications. Secondary outcome measures included SF-12, visual analog scale (VAS) assessing neck and arm pain, patient satisfaction, radiographic range of motion, and adjacent level degeneration. Patients were evaluated preoperatively and postoperatively at 6 weeks, 3, 6, 12, 18, and 24 months. The hypothesis was that the TDR success rate was non-inferior to ACDF at 24 months.


Overall success rates were 73.6% for TDR and 65.3% for ACDF, confirming non-inferiority (p < 0.0025). TDR demonstrated earlier improvements with significant differences in NDI scores at 6 weeks and 3 months, and VAS neck pain and SF-12 PCS scores at 6 weeks (p<0.05). Operative level range of motion in the TDR group was maintained throughout follow-up. Radiographic evidence of inferior adjacent segment degeneration was significantly greater with ACDF at 12 and 24 months (p < 0.05). AE rates were similar. 


Mobi-C TDR is a safe and effective treatment for single-level disc degeneration, producing outcomes similar to ACDF with less adjacent segment degeneration. Level of Evidence: Level I. 
Clinical relevance: This study adds to the literature supporting cervical TDR as a viable option to ACDF in appropriately selected patients with disc degeneration.

clinical outcome, randomized study, anterior cervical fusion, Cervical Spine, total disc replacement
Volume 8 Article 7