[Targeted small craniotomy and evacuation for subscute subdural hematomas: technical report of two cases]

The etiology and proper treatment of symptomatic subacute subdural hematomas remains to be elucidated. We describe two cases of this entity successfully treated with small craniotomy and evacuation. Both patients initially treated conservatively for traumatic thin subdural hematomas because of poor medical condition and mild neurological symptoms, but suffered abrupt neurological deterioration between 2 and 3 weeks after the admission. CT scan showed decreased density of hematomas with minimal increase in volume, and significant swelling of ipsilateral cerebral hemisphere. Urgent two-burr-hole small craniotomy was effective for evacuation of partially organized hematoma. During surgery, definite hematoma membrane was not confirmed. Postoperatively, brain swelling rapidly disappeared and both patients discharged ambulatory without neurological deficit. The present cases are a reminder of this peculiar type of hematoma in patients with delayed neurological deterioration after nonsurgical management of acute subdural hematoma. The rationale for use of small craniotomy is discussed in terms of current understanding of pathogenetic mechanism for this unusual condition.