Chronic subdural hematoma: Differences between unilateral and bilateral occurrence.

Chronic subdural hematoma (CSDH) is one of the most common neurological diseases. However, bilateral CSDH is more infrequent than unilateral CSDH, and the clinical and radiological characteristics are not well-defined. We aimed to investigate the clinical and radiological differences between bilateral and unilateral CSDH. A retrospective study was performed on 75 surgically-treated CSDH patients from January 2011 to December 2015. These patients were divided into unilateral and bilateral CSDH groups. The clinical features, radiological findings, surgical outcome, occurrence of postoperative intracranial bleeding, and recurrence were analyzed. 30.7% of patients had bilateral CSDH. The mean age was 79years and 68.8years for the bilateral and unilateral CSDH patients, respectively (p=0.001). The presence of a history of alcohol abuse was 8.7% and 32.7% in the bilateral and unilateral CSDH patients, respectively (p=0.028). The patients with bilateral CSDH were more likely to present with nausea or vomiting (p=0.048). A lesser degree of midline shift on computed tomographic (CT) scan was also observed in the bilateral group (p=0.001). Most patients had a favorable postoperative outcome, even with bilateral CSDH. In this study, we found that the patients with bilateral CSDH were older, had a lower prevalence of a history of alcohol abuse, presented more commonly with nausea or vomiting, and had a lesser degree of midline shift on CT. Burr-hole craniostomy with a closed-drainage system is a feasible and effective surgical technique for the treatment of unilateral or bilateral CSDH.