Correlation of Number of Seizures Recorded During Scalp Monitoring with Surgical Outcome
Abstract number :
2.227
Submission category :
Year :
2000
Submission ID :
2426
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Timothy W Powell, Nicholas D Lawn, Ruben I Kuzniecky, Robert C Knowlton, John W McBurney, Richard B Morawetz, Edward R Faught, Univ of Alabama, Birmingham, AL.
RATIONALE: Studies relating the number of seizures recorded during noninvasive scalp monitoring to the localization of the seizure focus have suggested that ictal events are the least sensitive compared to interictal localization and MRI. However, none have discussed whether the number of ictal events recorded is related to outcome. Could poor outcomes be due to recording too few seizures and potentially missing an independent focus? METHODS: Retrospective chart review of seizure monitoring admissions for patients with 1-5 years of follow-up after temporal lobectomy was performed. A total of 60 patients were consecutively selected. 30 had left temporal lobectomies, and 30 had right temporal lobectomies. Among each group of 30, 15 were seizure free and 15 had continued seizures following surgery. The number of seizures recorded during scalp monitoring was correlated with the surgical outcome. Mean seizure frequency among the groups was analysed. The number of patients proceeding to invasive monitoring was noted, but the number of seizures recorded invasively was not used in this analysis. RESULTS: The mean seizure frequency of the seizure free group was 3.83 (SD 1.7), and those with continued seizures was 4.13 (SD 2.0, p=0.54). 20% of the seizure free group required invasive monitoring, whereas 50% of the continued seizure group required invasive monitoring before surgery. (p=0.03) It is noted that those who failed surgery were 2.5 times more likely to have undergone invasive monitoring; and if patients had invasive monitoring, they were 1.9 times more likely to have seizures following surgery compared to those who had only noninvasive scalp monitoring. (CI 1.15-3.00) CONCLUSIONS: There was no statistical difference in the number of seizures recorded during scalp monitoring in patients who were seizure free vs. those who had continued seizures after temporal lobectomy. Our data suggest that failure to record an adequate number of seizures is not a major cause of surgical failure, and that uncertainty after the noninvasive monitoring is an unfavorable prognostic sign.