Original title: Association of body mass index with postoperative pulmonary complications and potential explanatory pathways in paediatric scoliosis correction surgery: a multicentre cohort study
Weihai Shi, Shouqiang Zhu, Yan Wang, Yanhua Sun +8 · September 2026
Children who undergo surgery to correct scoliosis, a sideways curvature of the spine, sometimes suffer serious lung issues afterward. These lung problems are known as postoperative pulmonary complications. Doctors wanted to know if a patient's body mass index, or BMI, which compares weight to height, links to these breathing troubles. Researchers studied surgical records from 1,165 young patients across three hospitals. They tested whether higher weight protects against lung issues, using machine learning to analyze the data and check pathways like nutrition, surgical blood loss, and the number of fused spine joints. They found that kids with higher BMI had lower odds of lung problems. Thinness or having a low BMI may act as a warning sign for higher risk. However, nutrition, blood loss, and spine fusion levels explained only tiny pieces of this connection. Adding BMI scores helped doctors predict lung complications slightly better right after surgery.
Imagine a group of students packing for a school trip. Some pack heavy bags and some pack light. You might think heavy bags are harder to carry, but in this case, students with light bags actually get more tired during the hike. That is surprising. In this paper, children with low BMI (like the light bags) had more lung problems after surgery, even though we often worry about high BMI. The researchers looked at what might explain it, like nutrition and blood loss, but those only partly explain the link.
For children undergoing scoliosis surgery, being underweight may be a bigger risk for lung complications than being overweight. This study shows that higher BMI is linked to fewer lung problems after surgery, but the reasons are not fully explained by nutrition or blood loss. Surgeons may need to pay more attention to thin patients, but the finding needs more confirmation.
This was a retrospective study, so it can show association but not prove causation. The causal forest estimates rely on assumptions that may not hold. The examined pathways (nutrition, blood loss, fusion levels) accounted for only small proportions of the BMI-PPC link, leaving other mechanisms unexplored. The predictive model had modest external performance when tested on a separate hospital. Results require prospective validation in different populations and settings.
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Association of body mass index with postoperative pulmonary complications and potential explanatory pathways in paediatric scoliosis correction surgery: a multicentre cohort study — Weihai Shi, Shouqiang Zhu, Yan Wang et al. — Annals of medicine — doi:10.1080/07853890.2026.2731716
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.