Proposal of Treatment Strategies for Bilateral Chronic Subdural Hematoma Based on Laterality of Treated Hematoma.

BACKGROUND: Chronic subdural hematoma (CSDH) is a disorder that is commonly seen in routine neurosurgery. Although risk factors for recurrence have been studied, the findings are inconsistent. Furthermore, bilateral CSDHs are operated unilaterally or bilaterally depending on symptoms or hematoma volume. Although there are cases in which hematomas on nonoperated side in unilaterally operated bilateral CSDHs requiring for additional operation, little have been studied on the effect of the surgical selection. The purpose of this study is to identify risk factors for recurrence in operated hematomas and additional operation in nonoperated hematomas and improve surgical strategy. MATERIALS AND METHODS: We retrospectively reviewed patients who underwent surgery in our facility for bilateral CSDHs between January 2011 and December 2016. Univariate and multivariate analyses were performed to examine the relationship between recurrence or requirement for additional operation and clinical and radiological variables. RESULTS: Recurrence was observed significantly more frequent for operated hematomas when hematoma type was separated type as reported previously. In unilaterally operated bilateral CSDHs, there were 22 hematomas on nonoperated side, and five hematomas required an additional operation after the first hospitalization. Increased volume of hematoma on the nonoperated side was the risk factors for additional operation (P = 0.022). Receiver operating characteristic (ROC) curve revealed that requirement for additional operation significantly increased when hematoma volume enlarged to approximately 44 cm3 or greater 1 day after operation. CONCLUSIONS: In unilaterally operated bilateral CSDHs, when hematoma volume on nonoperated side increased 1 day after the last operation, additional operation in the early stage is considerable to prevent re-hospitalization and deterioration of activities of daily living.