Brain Compression Tolerance Ratio: A Novel Clinical–Radiological Measure and Its Association with Early Postoperative Mobilization After Subdural Hematoma Surgery

Background/Objectives: We developed the Brain Compression Tolerance Ratio (BCTR), integrating the preoperative Glasgow Coma Scale (GCS) and midline shift, to explore the clinical–radiological relationship in patients undergoing subdural hematoma (SDH) surgery and its association with early postoperative mobilization. Methods: This retrospective study included 127 surgically treated patients. Early out-of-bed mobilization within 72 h was the primary outcome. BCTR was assessed using regression and receiver operating characteristic (ROC) analyses and compared with preoperative GCS and midline shift. Results: Early mobilization was achieved in 108 patients (85.0%). BCTR was associated with early mobilization in the primary preoperative model (adjusted odds ratio (OR) = 3.39, p = 0.033) and Firth regression (adjusted OR = 2.66, p = 0.038). The area under the curve (AUC) was 0.788 for BCTR, 0.866 for GCS, and 0.871 for the combined GCS–midline shift model (DeLong p = 0.137 and p = 0.100, respectively). Incremental-value analyses showed no additional clinical benefit. BCTR was not independently associated with postoperative GCS or hospital stay. Conclusions: BCTR is an exploratory clinical–radiological index relating preoperative neurological status to midline displacement. Although associated with early mobilization, it demonstrated no incremental predictive utility. Prospective studies with external validation are needed.