Postoperative Complications of Single-Level Lumbar Spine Fusion in Patients With Preoperative Vitamin D Deficiency: A Retrospective Cohort Study

Study Design Retrospective cohort study. Objectives To assess whether preoperative vitamin D deficiency is associated with increased postoperative complications after single-level lumbar fusion. Methods We queried a national EHR network for adults undergoing posterior/posterolateral single-level lumbar fusion. Vitamin D deficiency was defined by the most recent preoperative 25-hydroxyvitamin D <20 ng/mL. Patients with multilevel fusion, <2-year follow-up, scoliosis, or spinal cord neoplasm were excluded. Propensity-score matching (1:1) on demographics, Charlson Comorbidity Index, obesity, osteoporosis, nicotine dependence, vitamin D supplementation, celiac disease, inflammatory bowel disease, chronic pancreatitis, and cystic fibrosis yielded 1365 patients per cohort (from 1372 deficient and 89,165 non-deficient). Outcomes included 90-day incidence of readmission, emergency department (ED) utilization, deep vein thrombosis (DVT), pulmonary embolism (PE), pneumonia, sepsis, acute kidney injury (AKI), urinary tract infection (UTI), surgical site infection (SSI), and death. Instrumentation failure, pseudoarthrosis, and revision were assessed at 90 days, 1 year, and 2 years. Risk differences and relative risks (RR) were calculated; statistical significance was set to P < 0.05. Results Vitamin D deficiency was associated with higher 90-day risk of readmission (RR = 1.19), ED use (RR = 1.32), AKI (RR = 1.77), SSI (RR = 2.06), death (RR = 2.40), and pseudoarthrosis (RR = 1.47). Pseudoarthrosis risk remained higher at 1 year (RR = 1.43) and 2 years (RR = 1.40), and revision surgery was higher at 2 years (RR = 1.69). Conclusion Preoperative vitamin D deficiency was associated with increased short-term medical complications and higher long-term risks of pseudoarthrosis and revision after single-level lumbar fusion. These findings support assessing vitamin D status preoperatively to identify patients at greater risk.