Chronic subdural hematoma (C-SDH) is a common disease clinically. Nearly all patient have unilateral C-SDH, but bilateral C-SDH is not rare. We thought that there are the differences in clinical characteristics between unilateral and bilateral C-SDH even though we have good results through the simple burr hole drainage. The authors analyzed the clinical feature of unilateral and bilateral C-SDH.

Sixty seven C-SDH patients were included who were operated on burrhole trephination and closed system drainage between January, 1996 and December, 2005 in our hospital. The patents were divided 28 bilateral C-SDH patients (Group A) and 39 unilateral C-SDH patients (Group B). We analyzed etiology, co-existing disease, neurologic status at admission, radiologic hematoma thickness, drainage duration and amount after operation, postoperative complication, recurrence, neurologic status at discharge between two groups.

We have more male patients than female patients in both groups. Trauma is major etiology in two groups. The most of causes in hemorrhage are correlated with chronic medical diseases, but there is no difference at co-existing disease between two groups. At radiologic features, one side hematoma thickness in bilateral hematoma groups was thiner than that in unilateral hematoma groups. But, the sum of bilateral hematoma thickness is no difference of unilateral hematoma thickness. Drainage amount of hematoma is more in bilateral C-SDH, but there is no statistical difference. Recurrence rate is more in unilateral hematoma (10%) than in bilateral hematoma (4%). The good outcome is attained in Glasgow outcome scale (GOS) at discharge in both groups.

Bilateral hematoma patients had more coexisting disease, had more longer duration between symptom development and operation, and also more drainage amount of hematoma. Drainage amount would be correlated with preoperative clinical severity in this study. If there was more drainage amount of hematoma, there was more worse clinical outcome. In bilateral hematoma patients, clinical symptom was more worse than unilateral hematoma patients. Although bilateral chronic subdural hematoma patient would show worse clinical symptoms preoperatively, the postoperative results was as good as unilateral hematoma patient. The authors thought that we will improve the prognosis of bilateral C-SDH patients with poor neurologic symptom through rapid diagnosis and operation.