Development and validation of a recurrent prediction model for patients with unilateral chronic subdural hematoma without hematoma volumetric analysis

Objective: Approximately 10 % of patients with chronic subdural hematoma (CSDH) undergo reoperation after initial surgery. This study aimed to develop a predictive model for the recurrence of unilateral CSDH at initial surgery without hematoma volumetric analysis.Methods: This single-center retrospective cohort study evaluated pre-and postoperative computed tomography (CT) images of patients with unilateral CSDH. The pre-and postoperative midline shift (MLS), residual hema-toma thickness, and subdural cavity thickness (SCT) were measured. CT images were classified based on the internal architecture of the hematoma (homogenous, laminar, trabecular, separated, and gradation subtypes).Results: Total 231 patients with unilateral CSDH underwent burr hole craniostomy. After receiver operating characteristic analysis, preoperative MLS and postoperative SCT showed better areas under the curve (AUCs) (0.684 and 0.756, respectively). According to the CT classification of preoperative hematomas, the recurrence rate was significantly higher in the separated/gradation group (18/97, 18.6 %) than in the homogenous/ laminar/trabecular group (10/134, 7.5 %). Four-point score was derived from the multivariate model using the preoperative MLS, postoperative SCT, and CT classification. The AUC of this model was 0.796, and the recur-rence rates at 0-4 points were 1.7 %, 3.2 %, 13.3 %, 25.0 %, and 35.7 %, respectively.Conclusion: Pre-and postoperative CT findings without hematoma volumetric analysis may predict CSDH recurrence.