Long-Term Efficacy and Safety of Anterior Cervical Discectomy and Fusion in Single-Level Cervical Disk Disease: 7 Years Follow-up of Food and Drug Administration Investigational Exemption ProDisc-C Study

• Published in: Global spine journal 2014-05, Vol.4 (1_suppl), p.s-0034-1376678-s-0034-1376678
• Main Authors: Janssen, M., Kopjar, B., Zigler, J. E., Spivak, J. M., Murrey, D. B.
• Format: Article
• Language: English
• ISSN: 2192-5682; 2192-5690
• DOI: 10.1055/s-0034-1376678

Introduction ProDisc-C (Synthes Spine USA Products; LLC, West Chester, PA) began its FDA Investigational Device Exemption multicenter randomized study in 2003 and has received marketing approval by the FDA in 2007. This study reports final results of the 7-year follow-up. The aim of this study is to compare long-term efficacy and safety of single-level cervical arthroplasty using ProDisc-C (DePuy-Synthes, Inc) to anterior cervical discectomy and fusion (ACDF) in patients with symptomatic cervical disk disease. Materials and Methods Between August 2003 and January 2005, 209 patients with symptomatic single-level cervical degenerative disk disease refractory to conservative management were enrolled in a prospective, randomized, controlled trial. Of these, 103 received ProDisc-C and 106 ACDF. Patients were followed up for 7 years. The outcomes included Visual Analog Scale for Arm and Neck Pain, Neck Disability Index (NDI), MOS-Short Form 36 (MOS-SF36), neurologic success, adverse events related to the surgery, and secondary surgeries. At the final follow-up at 7 years, the overall follow-up rate was 79.0%. Statistical Analysis Discrepancies between the groups in preoperative demographics and postoperative outcome valuations were analyzed using the Fisher exact test for the categorical variables, and the t-test for the continuous variables. The changes in outcome scores at 2 and 7 years were analyzed using two-way repeated measurements analysis of covariance (ANCOVA) with one fixed factor (“GROUP”) (ACDF and ProDisc-C), one repeated factor (“TIME”) with two levels corresponding to two follow-up times (2 and 7 years), as well as the interaction effect between the GROUP and the TIME factors. Differences in proportions of secondary operations on the index surgical levels were analyzed by Fisher exact test. In the case of multiple secondary surgeries, each subject was counted only once. The time until the secondary surgery was analyzed by Kaplan-Meyer survival estimates, and the differences in survival tested by log-rank test. Results Table 1 shows adjusted means and their confidence intervals by treatment group. All outcomes improved compared with preoperative status in both study arms at 2 years (p < 0.05), except for the SF36 General Health (p > 0.05). At 7 years postoperative, the improvements were maintained for the same variables as at 2 years postoperative (p < 0.05). There were no significant differences between the ACDF and ProDisc-C patients in the exten