Vitamin D Status and Supplementation in Spine Surgery: A Narrative Review of the Current Evidence

Abstract

Bone quality is now recognized as an important factor in spinal fusion success. Since vitamin D helps the body absorb calcium, supports bone cells, and aids muscle function, improving vitamin D levels around surgery seems logical. A systematic review and meta-analysis available as a medRxiv preprint registered with PROSPERO in 2026 examined 13 studies on vitamin D in spine surgery patients. However, the review's conclusions were more cautious than the biological reasoning suggests. Vitamin D supplements did not clearly reduce pain after surgery or improve fusion rates. Some early analyses hinted at possible benefits for disability scores, bone quality, implant stability, and fracture risk, but these findings were based on a small number of studies, showed a lot of variation, and were influenced by removing certain studies. This review summarizes the current evidence, explains what is known and still uncertain about vitamin D supplements in spine fusion, and notes that while the biological reasons are strong, clinical proof is still lacking.