Motion analysis of dynamic cervical implant stabilization versus anterior discectomy and fusion: a retrospective analysis of 70 cases

Purpose Retrospective kinematic analysis of treated level, adjacent levels, and overall cervical spine after single-level dynamic cervical implant (DCI) stabilization versus anterior cervical discectomy and fusion (ACDF). Methods Between June 2009 and March 2013, 70 consecutive patients with a symptomatic single-level cervical degenerative disk disease (DDD) were enrolled in this study and divided into DCI ( n = 35) group and ACDF ( n = 35) group. All cases were followed up for more than 5 years. The study compared perioperative parameters; clinical outcomes; and radiological parameters. Kinematic analysis included range of motion (ROM) of treated level and adjacent level, overall ROM (C2–C7), and changes in adjacent disk spaces. Results There were no significant differences between the DCI group and ACDF group in terms of improvement in the SF-36, VAS, NDI, and JOA scores. DCI stabilization resulted in better ROM of C2–C7 and the treated level than ACDF did. The ROM of treated level decreased significantly at 24 months after surgery and last follow-up in the DCI group, and the C2–C7 ROM showed different degrees of reduction after the 24 months after surgery. Radiological evidence of adjacent segment degeneration (ASD) at last follow-up was observed in 4/22 patients (18.2%) in the DCI group and 5/23 patients (21.7%) in the ACDF group which was not a significant difference between groups ( p > 0.05). Conclusions DCI stabilization for the treatment of cervical DDD cannot preserve the normal kinematics of the cervical spine for a long time, especially the treated level. DCI stabilization cannot decrease the risk of ASD compared with ACDF. Graphical abstract These slides can be retrieved under Electronic Supplementary Material.