Vitamin D Status and Supplementation in Lumbar Spinal Fusion: A Systematic Review and Meta-Analysis of Radiographic and Clinical Outcomes.

This systematic review and meta-analysis evaluated the association between vitamin D status or vitamin D-related interventions and outcomes following lumbar spinal fusion. PubMed/MEDLINE, Scopus, and Web of Science were searched from inception to January 2026 in accordance with PRISMA guidelines. Studies including adult patients undergoing lumbar fusion with assessment of vitamin D status or supplementation and a comparator group were eligible. Random-effects models were used as the primary analyses. Nine studies were included. Five studies (n = 351) assessed radiographic fusion success, demonstrating a significantly higher likelihood of fusion in patients with better vitamin D status or supplementation (RR 1.25, 95% CI 1.13-1.38; I2 = 0%). Six studies (n = 3,081) evaluated fusion failure, showing a significantly lower risk in vitamin D-exposed groups (RR 0.45, 95% CI 0.27-0.76; I2 = 34.8%). Sensitivity analyses indicated that heterogeneity was partly related to differences in outcome definitions and study design. Patient-reported outcomes showed inconsistent results, with no significant effects in random-effects analyses and changes below minimal clinically important differences. Vitamin D exposure was associated with improved radiographic outcomes; however, findings should be interpreted cautiously due to clinical and methodological heterogeneity. Further prospective studies are required.