CT-derived thoracic muscle thickness is associated with prolonged hospitalization after video-assisted thoracoscopic...

Skeletal muscle depletion has been associated with adverse surgical outcomes, but conventional sarcopenia assessment using abdominal imaging is often unavailable in thoracic surgery patients. This study evaluated whether thoracic muscle thickness measured on routine preoperative chest computed tomography predicts postoperative recovery after video-assisted thoracoscopic surgery (VATS).

We retrospectively analyzed 301 patients undergoing VATS. Thoracic muscle thickness was measured at the T5, T8, and T10 vertebral levels, and average thoracic muscle thickness was calculated as the mean of these measurements. The primary clinically oriented outcome was prolonged hospitalization, defined as postoperative length of stay (LOS) >7 days. Continuous LOS was additionally analyzed as a supportive outcome. Multivariable logistic regression was used to assess predictors of prolonged hospitalization, while multivariable linear regression was performed as a secondary analysis of continuous LOS. Predictive performance was evaluated using receiver operating characteristic (ROC) analysis, and the incremental value of muscle thickness was assessed using net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

Lower thoracic muscle thickness was associated with longer postoperative hospitalization. In multivariable linear regression, average thoracic muscle thickness remained independently associated with LOS (β=-0.137, P=0.002). Logistic regression demonstrated that greater muscle thickness was associated with a lower risk of prolonged hospitalization (LOS >7 days) [odds ratio (OR) =0.92 per mm increase, P=0.004]. ROC analysis showed modest predictive ability [area under the curve (AUC) =0.59] for muscle thickness alone, which improved when incorporated into a clinical model (AUC =0.67). Patients in the lowest muscle tertile had more than twofold increased risk of prolonged hospitalization compared with those in the highest tertile (OR =2.12, P=0.007).

Thoracic muscle thickness measured on routine preoperative chest CT demonstrated a statistically significant but modest association with postoperative recovery after VATS and may provide complementary body-composition information alongside conventional perioperative assessment.