Prospective randomized study of cervical arthroplasty and anterior cervical discectomy and fusion with long-term follow-up: results in 74 patients from a single site

Abstract

Object: The purpose of this study was to evaluate the long-term results of cervical total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF) in the treatment of single-level cervical radiculopathy.

Methods: The results of 2 separate prospective, randomized, US FDA Investigational Device Exemption pivotal trials (Bryan Disc and Kineflex|C) from a single investigational site were combined to evaluate outcomes at long-term follow-up. The primary clinical outcome measures included the Neck Disability Index (NDI), visual analog scale (VAS), and neurological examination. Patients were randomized to receive cervical TDR in 2 separate prospective, randomized studies using the Bryan Disc or Kineflex|C cervical artificial disc compared with ACDF using structural allograft and an anterior plate. Patients were evaluated preoperatively; at 6 weeks; at 3, 6, and 12 months; and then yearly for a minimum of 48 months. Plain radiographs were obtained at each study visit.

Results: A total of 74 patients were enrolled and randomly assigned to either the cervical TDR (n = 41) or ACDF (n = 33) group. A total of 63 patients (86%) completed a minimum of 4 years follow-up. Average follow-up was 6 years (72 months) with a range from 48 to 108 months. In both the cervical TDR and ACDF groups, mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the minimum 48-month follow-up (p < 0.001). Similarly, the median VAS pain scores improved significantly by 6 weeks and remained significantly improved throughout the minimum 48-month follow-up (p < 0.001). There were no significant differences between groups in mean NDI or median VAS scores. The range of motion (ROM) in the cervical TDR group remained significantly greater than the preoperative mean, whereas the ROM in the ACDF group was significantly reduced from the preoperative mean. There was significantly greater ROM in the cervical TDR group compared with the ACDF group. There were 3 reoperations (7.3%) at index or adjacent levels in the cervical TDR group; all were cervical laminoforaminotomies. There were 2 adjacent-level reoperations in the cervical TDR group (4.9%). There was 1 reoperation (3.0%) in the ACDF group at an index or adjacent level (a second ACDF at the adjacent level). There was no statistically significant difference in overall reoperation rate or adjacent-level reoperation rate between groups.

Conclusions: Both cervical TDR and ACDF groups showed excellent clinical outcomes that were maintained over long-term follow-up. Both groups showed low index-level and adjacent-level reoperation rates. Both cervical TDR and ACDF appear to be viable options for the treatment of single-level cervical radiculopathy.