Comparison of zero-profile anchored spacer versus plate-cage construct in treatment of cervical spondylosis with regard to clinical outcomes and incidence of major complications: a meta-analysis

Purpose: Meta-analysis was conducted to evaluate whether zero-profile anchored spacer (Zero-P) could reduce complication rates, while maintaining similar clinical outcomes compared to plate-cage construct (PCC) in the treatment of cervical spondylosis. Methods: All prospective and retrospective comparative studies published up to May 2015 that compared the clinical outcomes of Zero-P versus PCC in the treatment of cervical spondylosis were acquired by a comprehensive search in PubMed and EMBASE. Exclusion criteria were non-English studies, noncomparative studies, hybrid surgeries, revision surgeries, and surgeries with less than a 12-month follow-up period. The main end points including Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) scores, cervical lordosis, fusion rate, subsidence, and dysphagia were analyzed. All studies were analyzed with the RevMan 5.2.0 software. Publication biases of main results were examined using Stata 12.0. Results: A total of 12 studies were included in the meta-analysis. No statistical difference was observed with regard to preoperative or postoperative JOA and NDI scores, cervical lordosis, and fusion rate. The Zero-P group had a higher subsidence rate than the PCC group (P<0.05, risk difference =0.13, 95% confidence interval [CI] 0.00-0.26). However, the Zero-P group had a significantly lower postoperative dysphagia rate than the PCC group within the first 2 weeks (P<0.05, odds ratio [OR] =0.64, 95% CI 0.45-0.91), at the 6th month [P<0.05, OR = 0.20, 95% CI 0.04-0.90], and at the final follow-up time [P<0.05, OR =0.13, 95% CI 0.04-0.45]. Conclusion: Our meta-analysis suggested that surgical treatments of single or multiple levels of cervical spondylosis using Zero-P and PCC were similar in terms of JOA score, NDI score, cervical lordosis, and fusion rate. Although the Zero-P group had a higher subsidence rate than the PCC group, Zero-P had a lower postoperative dysphagia rate and might have a lower adjacent-level ossification rate.