Abstract
Dear Editor,
We read with interest the study by Mihas et al examining the association between BMI Z-score and postoperative complications in pediatric neuromuscular scoliosis surgery. In 147 patients, overall complication rate was 44.2%, including deep surgical site infection (SSI) in 11.6%, pneumonia in 6.8%, 30-day readmission in 15.0%, and reoperation within 90 days in 16.3%. Higher BMI Z-scores were associated with SSI, readmission, and reoperation, whereas lower BMI Z-scores were associated with pneumonia, suggesting BMI Z-score may aid perioperative risk assessment in this complex population.
One consideration is the assumption of linearity when modelling BMI Z-score. Very low BMI may indicate malnutrition and limited respiratory reserve, increasing pulmonary risk, while higher BMI may contribute to wound tension and impaired tissue perfusion. The opposite associations observed for pneumonia vs wound-related outcomes suggest risk may accumulate at both extremes rather than change uniformly. Flexible approaches, such as spline modelling, could better capture these nonlinear relationships.
Another point is that BMI Z-score may reflect underlying disease severity. Patients with pneumonia had lower BMI but also higher rates of gastrostomy dependence, tracheostomy, and chronic pulmonary disease, indicating low BMI may cluster with broader vulnerabilities.
Finally, BMI interpretation may be limited by measurement challenges and altered body composition in this population.
Overall, this study provides valuable insight into perioperative risk in pediatric neuromuscular scoliosis. Further exploration of nonlinear modelling, disease severity, and anthropometric considerations could refine the role of BMI Z-score in future risk stratification.