Unilateral porencephalic cysts are brain cavities resulting from perinatal vascular occlusion, most often in the territory of the middle cerebral artery. Severe neurological deficits such as hemiparesis are commonly associated with porencephalic cysts as well as intractable seizures. Between 1978 and 1992 we treated 37 children with medically intractable epilepsy and porencephalic cysts by uncapping and fenestration of these cysts to the lateral ventricle. We retrospectively reviewed the outcome of these patients with regard to seizures, paresis, and neurosurgical complications.

Of 37 children, 62% (23/37) were postoperatively seizure-free. Nine patients (24%) had a reduction of seizures and 5 children (14%) remained unchanged. Of 30 patients with preoperative hemiparesis, 30% (11/30) improved after the operation over a follow-up period of 1 year. The size of the fenestration varying from 0.4 cm2 to 2.0 cm2 did not influence the seizure or hemiparesis outcome. However, with respect to the postoperative complications a size of 1.0 cm2 is recommended. The leading postoperative problem was a subcutaneous/subgaleal cushion of cerebrospinal fluid (CSF), which affected 12 children (12/37). The treatment consisted of pressure dressings. A dura patch covering the iatrogenic dura defect could not prevent or reduce CSF leakage, but prolonged the postoperative fever period. Postoperative fever occured in 36 children (36/37) and was due to an aseptic meningitis.

Nine of 13 postoperative CT-scans of the head showed a reduction of the cyst size along with seizure reduction. Four CT-scans (4/13) revealed an unchanged cyst size in association with seizure reduction.

Children with porencephalic cysts and seizures benefit from uncapping and fenestration of these cysts to the lateral ventricle. Concomitant perioperative complications are not severe and are easily to treat.