Risk Factors Predicting Recurrence of Bilateral Chronic Subdural Hematomas after Initial Bilateral Evacuation.

Background: Most patients with bilateral chronic subdural hematomas (bCSDH) undergo initial bilateral evacuation. Risk factors associated with the recurrence of bCSDH after initial bilateral evacuation have not been published to date. In this study, we aimed to identify risk factors related to recurrence of bCSDH after initial bilateral evacuation, and to develop a prognostic grading system for clinical reference.

Methods: This study included 102 patients with bCSDH who underwent initial bilateral evacuation. Predictors of recurrence were identified via univariate analysis and multivariate logistic regression analysis. A prognostic grading system was created based on the independent predictors combined with a cutoff value. All cases were scored according to the prognostic grading system, and the recurrence rates of the different scores were reanalyzed.

Results: Anticoagulant use (odds ratio [OR], 84.266; 95% confidence interval [CI], 13.113-541.522; P < 0.001), severe brain atrophy (OR, 11.551; 95% CI, 2.558-52.163; P = 0.001), and postoperative pneumocephalus volume (PostPV) (OR, 0.978; 95% CI, 0.957-1.000; P = 0.049) were independent risk factors for the recurrence of bCSDH after initial bilateral evacuation. The cutoff value of PostPV was >20.9484 cm. A prognostic grading system was then developed, and the recurrence rates based on score were determined. Rates were 2.8% for a score of 0-1, 28.1% for a score of 2-3, and 100% for a score of 4-5, showing a significant increase in risk with increasing score (P < 0.001).

Conclusions: Anticoagulant use, severe brain atrophy, and PostPV were identified as independent risk factors for recurrence of bCSDH after initial bilateral evacuation. The prognostic grading system for recurrence of bCSDH after initial bilateral evacuation is reliable and applicable for clinical reference.