Interhemispheric and bilateral chronic subdural hematoma.

Data on bilateral chronic subdural hematomas (CSHs) are scant, including information on the frequency of symptoms, response to various treatments, and postoperative complications, compared with data on unilateral CSH. Bilateral CSHs constitute a fair portion of CSHs, especially in patients older than 75 years and in those with coagulation abnormalities. The presenting symptoms are those of increased intracranial pressure and mass effect. Computed tomography of the head is the best study for the diagnosis and follow-up of bilateral CSHs, although magnetic resonance imaging is a more sensitive modality. Treatment of bilateral CSHs presents its own unique set of problems. New hemorrhage on the contralateral side and shift of midline structures are concerns and can be avoided by simultaneous bilateral decompression. Twist-drill craniostomy, burr-hole washout, and craniotomy are the mainstays of treatment, with subdural-peritoneal shunting reserved for intractable cases.