Structural allograft versus Polyetheretherketone cage in Anterior Cervical Discectomy and Fusion: A Meta-analysis

BACKGROUND: Polyetheretherketone (PEEK) cages and structural allografts (SAs) are commonly used in Anterior Cervical Discectomy and Fusion (ACDF), yet their postoperative results remain uncertain. This meta-analysis was conducted to determine whether there were any differences in outcomes between patients who received these two grafts in ACDF.

METHODS: We comprehensively searched electronic databases up to August 2023. Observational studies or randomized controlled trials reported postoperative outcomes, including fusion, subsidence, reoperation rates, and patient-reported outcomes through the Neck Disability Index (NDI), the Visual Analog Scale (VAS) for neck and arm pain, and the Japanese Orthopedic Association (JOA)/modified JOA score following primary ACDF using SA or PEEK cage. The results are presented in odds ratios (ORs) or mean differences with corresponding 95% confidence intervals (CIs).

RESULTS: Eleven studies were included, with 1213 patients (788 receiving SAs and 425 receiving PEEK cages). Patients having SA had significantly higher fusion (OR: 1.84, 95% CI: 1.27-2.67, p = 0.001) and lower subsidence (OR: 0.50, 95%CI: 0.30-0.86, p = 0.01) rates when compared with the PEEK cage. There was no difference in revision rate between SA or PEEK cage (p = 0.88). Two grafts demonstrated similar clinical improvements in NDI (p = 0.31), VAS for the neck (p = 0.77) and arm pain (p = 0.22), and JOA/mJOA score (p = 0.99).

CONCLUSION: SA demonstrates better fusion and lower subsidence rates than the PEEK cage in ACDF. Nevertheless, these two cages resulted in equally successful postoperative clinical performances.