Does instrumented fusion improve clinical outcomes in posterior surgery for cervical ossification of the posterior longitudinal ligament? A systematic review and meta-analysis.

Abstract

Posterior decompression for cervical ossification of the posterior longitudinal ligament (OPLL) is commonly performed using laminoplasty (LAMP) or posterior decompression with fusion (PDF). However, the relative benefits and risks of these procedures remain uncertain. This study aimed to compare clinical and radiographic outcomes between LAMP and PDF using a systematic review and meta-analysis. A systematic search of PubMed, Embase, and the Cochrane Library was conducted to identify studies comparing LAMP and PDF for cervical OPLL. Extracted data included neurological function, Neck Disability Index (NDI), neck pain, postoperative complications, and sagittal alignment. Neurological improvement was assessed using the Japanese Orthopaedic Association (JOA) score and recovery rate, with subgroup analyses performed according to K-line status. Meta-analyses were conducted to compare outcomes between procedures. The certainty of evidence was evaluated using the GRADE approach. Seventeen studies were included. Overall neurological recovery was similar between LAMP and PDF. In subgroup analysis, PDF demonstrated significantly greater improvement in patients with K-line (-) OPLL. Neck Disability Index scores did not differ between procedures. Postoperative neck pain was more frequent after PDF, and complication rates were consistently higher with PDF. Sagittal alignment parameters, including C2-7 sagittal vertical axis and C2-7 cervical lordosis angle, were similar between the two procedures. Neurological improvement following posterior decompression for cervical OPLL was similar between LAMP and PDF overall. While PDF showed significantly greater improvement in patients with K-line (-) OPLL, it was associated with higher rates of postoperative neck pain and complications. These findings indicate that PDF was associated with greater neurological improvement in patients with K-line (-) OPLL; however, this finding should be interpreted with caution given the observational nature of the included studies and the very low certainty of evidence, and should be considered hypothesis-generating.