Abstract:Objective To investigate the incidence and influencing factors of subdural effusion in patients undergoing decompressive craniectomy (DC), to construct and validate a prediction model based on these findings, and therefore to provide clinical guidance for reducing the risk of subdural effusion following DC.Methods A total of 117 patients who underwent DC surgery in our hospital from January 2021 to December 2022 were retrospectively analyzed. According to the presence of postoperative subdural effusion, patients were divided into the occurrence group (33 cases) and the non-occurrence group (84 cases). The factors affecting the occurrence of postoperative subdural effusion were analyzed, based on which a nomogram model was constructed to predict the risk of postoperative subdural effusion. The area under the receiver operating characteristic (ROC) curve (AUC) was used to analyze the predictive efficacy of the prediction model for postoperative subdural effusion.Results The proportions of patients aged ≥ 60 years, with subarachnoid hemorrhage, undergoing cortical incision, with midline shift ≥10 mm, and with intracranial infection in the occurrence group were all higher than those in the non-occurrence group (P < 0.05), and the proportion of patients with the distance from the edge of the bone flap to the midline ≥ 2 cm in the occurrence group was lower than that in the non-occurrence group (P < 0.05). Multivariable Logistic regression analysis demonstrated that subarachnoid hemorrhage [O^R = 4.295 (95% CI: 1.953, 9.443) ], long midline shift distance [O^R = 5.526 (95% CI: 2.962, 10.306) ], and intracranial infection [O^R = 6.43 (95% CI: 2.202, 18.800) ] were risk factors for postoperative subdural effusion (P < 0.05), and that long distance from the edge of the bone flap to the midline [O^R = 0.196 (95% CI: 0.066, 0.578) ] was a protective factor (P < 0.05). The nomogram prediction model constructed based on the aforementioned influencing factors showed a C-index of 0.847 (95% CI: 0.752, 0.923) after the internal validation using the Bootstrap method, and the calibration curve for predicting postoperative subdural effusion closely approached the ideal curve (P > 0.05). The results of ROC curve indicated that the sensitivity and specificity of the nomogram model for predicting postoperative subdural effusion were 85.70% (95% CI: 0.520, 0.926) and 86.60% (95% CI: 0.651, 0.930), respectively, with the AUC being 0.872 (95% CI: 0.783, 0.960) (P < 0.05).Conclusions Subarachnoid hemorrhage, long midline shift distance, and intracranial infection are independent risk factors for postoperative subdural effusion in patients undergoing DC, and long distance from the edge of the bone flap to the midline is an independent protective factor. The nomogram risk prediction model based on the above factors can better evaluate the risk of postoperative subdural effusion in these patients.