Comparison of Zero-profile Device Versus Plate-and-Cage Implant in the Treatment of Symptomatic Adjacent Segment Disease after Anterior Cervical Discectomy and Fusion: A Minimum 2-Year Follow-Up Study

OBJECTIVE: The purpose of this study was to compare the clinical efficacy of anterior cervical discectomy and fusion (ACDF) with Zero-profile device (Zero-p) and traditional cervical plate-and-cage implant in the treatment of symptomatic adjacent segment disease (ASD) and to determine the optimal reoperation procedure. METHODS: This was a retrospective study of 58 patients with symptomatic ASD after an initial ACDF surgery and who had undergone a reoperation with ACDF with Zero-p (n = 27) and cervical plate-and-cage (n = 31) at our medical center between January 2010 and December 2015. RESULTS: The Japanese Orthopaedic Association score, Neck Disability Index score, Visual Analog Scale score, C2-C7 Cobb angle, and disc height index demonstrated significant improvements compared with the preoperative in both Zero-p and plate-and-cage groups (P < 0.05). However, there were no differences between the two groups (P > 0.05). The reoperation time for the Zero-p group (83.4 +/- 18.9 min) was less than that for the plate-and-cage group (96.5 +/- 20.1 min), with significant difference (P < 0.05). Five patients (8.6%) had cage subsidence, and 14 patients (24.1%) had dysphagia after the reoperation. There was no statistical significance in the difference between the 2 groups in cage subsidence (P > 0.05). However, the incidence of dysphagia in the plate-and-cage group (38.7%) was higher than in the Zero-p group (7.4%), with a significant difference (P < 0.05). CONCLUSIONS: ACDF with Zero-p obtaining the same surgical efficacy, compared with traditional cervical plateand-cage, can significantly shorten the reoperation time and reduce the incidence of postoperative dysphagia. This option may be preferable for symptomatic patients with ASD qualifying for the anterior approach, in terms of biomechanics and surgical outcomes.