Comparative prognostic value of CT-derived temporal muscle parameters in chronic subdural hematoma: a retrospective cohort study

Chronic subdural hematoma (CSDH) is a common neurosurgical condition in older adults, with variable postoperative recovery. Simple imaging markers reflecting systemic physiological reserve may improve perioperative risk stratification in this population. Temporal muscle thickness (TMT) measured on routine cranial computed tomography (CT) images is a proposed imaging-based surrogate marker of sarcopenia. However, the comparative prognostic value of different temporal muscle metrics remains unclear. We aimed to compare CT-derived TMT, temporal muscle area (TMA), and temporal muscle volume (TMV) as predictors of postoperative outcomes in patients undergoing surgery for CSDH. This retrospective cohort study included 197 patients who underwent burr-hole surgery for CSDH. TMT, TMA, and TMV were measured on preoperative non-contrast CT images. The primary outcome was an unfavorable functional outcome at discharge (modified Rankin scale score, 3–6). Secondary outcomes included 3-month functional outcome and perioperative complications. Lower TMT, TMA, and TMV were independently associated with unfavorable functional outcomes at discharge. In multivariable analysis, TMT showed the strongest inverse association with outcome, with each 1-standard deviation increase associated with lower odds of unfavorable outcome ( p < 0.001). TMT had the highest area under the curve point estimate among the three parameters (area under the curve: 0.796, 95% confidence interval 0.73–0.86). Patients with lower TMT also exhibited higher rates of perioperative complications and poorer functional outcomes. CT-derived temporal muscle parameters were independently associated with postoperative functional outcomes in patients undergoing surgery for CSDH. TMT appeared to provide a favorable balance between prognostic information and clinical practicality and may serve as a simple imaging marker reflecting systemic vulnerability.