Is PEEK cage better than titanium cage in anterior cervical discectomy and fusion surgery? A meta-analysis

BACKGROUND This meta-analysis was performed to identify the benefits and disadvantages of the PEEK cage and titanium cage. METHODS We used "cervical or cervicle", "titanium", and "polyetheretherketone or PEEK" as keywords. Medline, Embase, Cochrane Central Register of Controlled Trials and other databases were searched to identify eligible studies that were published before October 2015. In addition, the Google search engine was used to manually search for relevant journals or conference proceedings. Randomized controlled trials and non-randomized controlled trials that compared the PEEK cage and titanium cage for anterior cervical surgery were included. The meta-analysis was performed with RevMan 5.1 software. RESULTS Two randomized and two non-randomized clinical trials were retrieved with a total of 184 segments from 107 patients in the PEEK cage group and 211 segments from 128 patients in the titanium cage group. The quality assessment scores ranged from 16 to 18 with high heterogeneity. There were no differences in functional status according to the Odom criteria, fusion rate, final local segmental angle and loss of correction between the two groups. Although more subsidence occurred in the titanium cage group, the effects of loss of the local segmental angle or the whole cervical Cobb angle on cervical function in the long-term are still not clear. CONCLUSION The present meta-analysis indicated no significant difference in functional and radiographic performance between the PEEK and titanium cages, although more subsidence occurred in the titanium cage group. More high-quality studies are needed to confirm these results to offer more information for the choice in clinical practice.