Postoperative muscle mass depletion in older patients undergoing major elective surgery

In older patients, the impact of surgery and postoperative recovery on skeletal muscle parameters remains poorly investigated. We aimed to assess changes in skeletal muscle parameters after major elective surgery and explore factors associated with total psoas index (TPI) reduction. This retrospective, post hoc analysis included 51 patients aged 70 years or older who underwent major elective general or urologic surgery and had preoperative and postoperative computed tomography (CT) scans available. The primary endpoint was the change in TPI between preoperative and postoperative CT. At postoperative CT follow-up, TPI decreased by 14% (mean [SD] paired difference -0.51 [0.77] cm²/m²) and muscle attenuation by 15% (both p < 0.001). The prevalence of low TPI increased from 13 patients preoperatively to 24 postoperatively. Preoperative low TPI was not significantly associated with postoperative outcomes, while greater TPI reduction was associated with longer hospital length of stay and intensive care unit admission in univariable analyses, but these associations were not confirmed after multivariable adjustment. These findings might suggest a postoperative decrease in skeletal muscle parameters in older adults, although their clinical relevance requires further investigation.