Delayed intracranial hematoma following stereoelectroencephalography for intractable epilepsy: case report.

Intracranial bleeding following stereoelectroencephalography (sEEG) is rare and commonly occurs early after electrode implantation. The authors report the case of a delayed intracranial hematoma following sEEG. This 10-year-old boy was referred to the authors' department to undergo an sEEG study for intractable epilepsy, with the hypothesis of a single localized epileptic zone in the left precentral region. To perform the exploration, 14 depth electrodes were implanted under stereotactic conditions. The results of a postoperative CT scan performed routinely at the end of the surgical procedure were normal. Eight days later, following an epileptic seizure, the child's condition worsened. The neurological examination revealed a left hemiparesis, agitation, and coma due to a right subdural hematoma with intraparenchymal bleeding. Despite a surgical evacuation followed by a decompressive craniectomy, the curative treatments were stopped 1 week later due to severe diffuse ischemic lesions found on MRI studies. This is the first observation of a delayed hematoma following an sEEG procedure. The mechanism underlying this complication remains unclear, but the rupture of a growing pseudoaneurysm caused by the electrode's implantation or the tearing of a neighboring vessel by an electrode were suspected. In consequence, physicians must remain vigilant during the entire sEEG recording period and probably also several days after electrode removal.