Association Between BMI Z-Score and Postoperative Complications in Pediatric Neuromuscular Scoliosis Surgery

Study Design: Single-center retrospective review. Objective: To investigate the association between BMI Z-scores and postoperative complications in pediatric patients with neuromuscular scoliosis undergoing spinal instrumentation. Methods: Pediatric patients who underwent spinal instrumentation for neuromuscular scoliosis from July 2012 to June 2016 with a minimum 2-year follow-up were included. BMI and BMI Z-scores were calculated, and patients were stratified into CDC-defined BMI-for-age percentiles: underweight (<5th percentile), normal (5th to <85th percentile), overweight (85th to <95th percentile), and obese (≥95th percentile). Logistic regression assessed associations of BMI, BMI Z-score, and BMI groups with postoperative complications. Results: In total, 147 patients were included. Average follow-up was 3.2 ± 1.4 years. The most common diagnosis was cerebral palsy (39.5%). Complications occurred in 65 (44.2%) patients: 32 (21.8%) had a surgical site infection (SSI), 10 (6.8%) developed pneumonia, and 24 (16.3%) required return to the operating room within 90 days. Higher BMI Z-score was associated with increased odds of deep SSI (OR = 1.50, P = 0.039), 30-day readmission (OR = 1.45, P = 0.045), and reoperation within 90 days (OR = 1.52, P = 0.026), and decreased odds of pneumonia (OR = 0.77, P = 0.041). Similar associations were seen for BMI. Conclusion: Higher BMI Z-scores were associated with increased odds of deep SSI, readmission within 30 days, and return to the operating room within 90 days. Lower BMI Z-scores were associated with increased risk of developing pneumonia; however, this should be interpreted with caution as these patients had baseline pulmonary comorbidities. BMI Z-scores may be a useful adjunct for preoperative risk stratification in pediatric neuromuscular scoliosis patients undergoing spinal instrumentation. Level of Evidence: Prognostic Level III.