Abstracts

RATIONALE:_Intraoperative thiopental activation has been used to localize neocortical epileptogenic regions for resection. However, there have been no follow-up studies to determine if this procedure is associated with good seizure control. METHODS: We reviewed records of 17 children, ages 5 mo to 17 yrs (median=45 mo), who underwent thiopental activation during ECoG. Ten patients had developmental delay prior to surgery. Seizure types included infantile spasms (IS)(n=9), mixed (n=2), epilepsia partialis continua (EPC) (n=1), and partial seizures (n=5). RESULTS: Intraoperative thiopental provoked epileptiform discharges in 4, beta gradient in 8 and no consistent effect in 5 patients. Three patients underwent lobectomies (T=2, F=1), multilobar resections (TOP=9, PT=1, FP=2), multiple subpial transections (MST)=1 and hemispherectomy=1. Five patients(multilobar=4, MST=1) required a second surgery with a hemispherectomy performed in 2. Pathology ranged from cortical dysplasia (n=8), stroke (n=2), tumor (n=1), cystercercosis (n=1), Rasmussen's (n=1), unidentifiable (n=3), and one with leukodystrophy only seen at pathology. Two of the patients died after surgery; another was lost to follow-up and a fourth was operated 7 months ago. Of the 13 remaining patients, median follow-up was 5 years. Three are seizure free, 2 have >75% improvement of seizures, 6 show no change, and 2 were seizure free for up to 2 years before recurrence. All patients who had poor development after surgery also had frequent seizures. Four of 5 patients who were seizure free developed beta gradients seen on thiopental testing. CONCLUSIONS: Of the 13 patients with intraoperative thiopental activation tests, 5 (38%) were seizure free post-surgery. Poor seizure outcome was noted with older children, type of seizure (mixed, EPC, and IS), nonlocalizing scalp EEG findings, or noncongruent data prior to surgery. If there is a clear beta gradient noted, it may provide additional information for defining the zone of cortical abnormality. However, there still needs further research to determine the sensitivity of thiopental testing in surgical outcome. Supported by NIH grant NS 38992