Abstract

Cervical fusion, particularly anterior cervical discectomy and fusion, is the standard treatment for degenerative cervical disease. With the global rise in diabetes mellitus (DM), understanding its impact on surgical outcomes is crucial. This study systematically reviewed and meta-analyzed the influence of DM on nonunion and patient-reported quality-of-life (QOL) outcomes after cervical fusion. Following the PRISMA 2020 guidelines, PubMed, Scopus, and Web of Science were searched through April 2025. Comparative cohort studies reporting fusion outcomes in DM and non-DM patients were included. Primary outcomes were nonunion rates and postoperative patient-reported outcome measures, including the SF-12 physical component summary (PCS), and the visual analog scale (VAS) for pain. Study quality was appraised using the methodological index for non-randomized studies tool, and pooled estimates were calculated using a random-effects model. Six cohort studies (1,323 DM vs. 1,848 non-DM) met the inclusion criteria. The overall quality was moderate. DM did not significantly increase the risk of nonunion (OR: 0.93; 95% CI: 0.59-1.47; p-value = 0.81; I² = 42%). However, DM was associated with poorer QOL (SF-12 PCS: SMD −0.23; 95% CI: −0.44 to −0.02; p-value = 0.03) and higher postoperative pain (VAS: SMD 0.22; 95% CI: 0.11-0.34; p < 0.001). DM does not appear to increase nonunion risk after cervical fusion, likely reflecting the cervical spine’s favorable biomechanical and vascular milieu. Nonetheless, diabetic patients report worse functional recovery and pain outcomes, underscoring the need for rigorous perioperative diabetes management to optimize QOL.

Key words: Cervical fusion, anterior cervical discectomy and fusion, diabetes mellitus, meta-analysis, spine surgery.