Risk factors for postoperative recurrence of chronic subdural hematoma and construction and validation of an online dynamic nomogram prediction model.

Objective: To investigate factors associated with postoperative recurrence in patients with chronic subdural hematoma (CSDH) and to construct and internally validate an online dynamic nomogram for individualized recurrence-risk estimation. Methods: This retrospective single-center study included 284 surgically treated patients with CSDH between January 2018 and May 2025. Before model development, the cohort was divided at a 7:3 ratio into a training cohort ( Results: Overall, 54 of 284 patients (19.01%) experienced recurrence; 33 recurrence events occurred in the training cohort and 21 in the validation cohort. Smoking history, laterality, hematoma density, greatest hematoma thickness, cerebral midline shift ≥10 mm, and postoperative pneumocephalus were statistically significant in the multivariable analysis. The AUC was 0.89 (95% CI, 0.82-0.95, sensitivity 0.82, specificity 0.85) in the training cohort and 0.74 (95% CI, 0.59-0.88, sensitivity 0.52, specificity 0.85) in the validation cohort. Bootstrap optimism correction yielded an apparent AUC of 0.892, a mean optimism of 0.021, and an optimism-corrected AUC of 0.871. In the training cohort, the Hosmer-Lemeshow test showed no statistically significant evidence of lack of fit ( Conclusion: The online nomogram provides a convenient framework for individualized recurrence risk estimation. Further external multicenter validation is warranted to assess its generalizability and clinical applicability.