Is There a Correlation Between Preoperative or Postoperative Vitamin D Levels with Pseudarthrosis, Hardware Failure, and Revisions After Lumbar Spine Fusion?

Background: Vitamin D deficiency is a well-known cause of postoperative complications in patients undergoing orthopedic surgery. Orthopedic complications seen in vitamin D deficiency include nonunion, pseudarthrosis, and hardware failure. We seek to investigate the relationship between vitamin D deficiency and outcomes after lumbar spinal fusions. Methods: A retrospective patient chart review was conducted at a single center for all patients who underwent lumbar spinal fusions from January 2015 to September 2017 with preoperative or postoperative vitamin D laboratory values. We recorded demographics, social history, medications, pre-existing medical conditions, bone density (dual-energy x-ray absorptiometry) T-scores, procedural details, 1-year postoperative Visual Analog Score (VAS), documented pseudarthrosis, revisions, and hardware failure. A total of 150 patients were initially included in the cohort for analysis. Results: Overall, preoperative and postoperative vitamin D levels were not significantly associated with a vast majority of the patient characteristics studied, including comorbidities, medications, or surgical diagnoses (P > 0.05). Age at surgery was significantly associated with vitamin D levels; older patients had higher serum levels of vitamin D both preoperatively (P = 0.03) and postoperatively (P = 0.01). Those with a higher average body mass index had lower vitamin D in both groups (P = 0.02). Vitamin D levels were not significantly associated with rates of postoperative pseudarthrosis, revision, or hardware complications (P > 0.05). VAS pain score at 1 year and smoking status preoperatively or postoperatively were not associated with vitamin D levels (P > 0.05). Conclusions: Both preoperative and postoperative vitamin D levels were not significantly associated with an increased or decreased risk of pseudarthrosis, revision surgery, hardware failure, or 1-year VAS pain score after lumbar spine fusion surgery.