INDICES OF RESECTIVE SURGERY EFFECTIVENESS FOR INTRACTABLE NON-LESIONAL FOCAL EPILEPSY
Abstract number :
3.202
Submission category :
Year :
2002
Submission ID :
49
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Gobi R. Ganapathy, Warren T. Blume, David Munoz, Donald H. Lee. Clinical Neurological Sciences, The University of Western Ontario, London, Ontario, Canada
RATIONALE: Patients undergoing epilepsy surgery without demonstrable specific lesions have mediocre results. Are there indices distinguishing patients with good results from those with bad? We present an enlarged series compared to a 1997 abstract with longer followup.
METHODS: Of 685 patients undergoing focal resection from 1989 to 1999, 70 (10%) had normal or non-specific histology. These were followed from 2-8.5 years (mean 3.75 years). All 70 patients had normal neuroimaging and normal or non-specific histological abnormalities as mild gliosis.
RESULTS: Among 70 patients with intractable focal epilepsy and no specific lesion, outcome after resective surgery was polarised: 26 (37%) became seizure-free (SF) and 27 (39%) were not helped. Eighteen (42%) of standard temporal resections rendered patients SF, somewhat more than 8 (30%) of 27 other procedures. To seek reliable prognostic factors the subsequent correlative data compared features of the 26 SF patients with the 27 unhelped. Although ictal semiology helped localise epileptogenesis, it and other aspects of seizure and neurological history failed to predict surgical outcome. However, two aspects of pre-operative scalp EEGs correlated with SF outcomes: 1) among 25 patients in whom [gt]50% of clinical seizures arose from the later resected lobe and no other origins, 18 (72%) became SF compared to 7 (28%) of 25 with other ictal profiles, 2) fifteen (88%) of 17 patients whose interictal and ictal EEGs lacked features indicative of multifocal epileptogenesis became SF compared to 10 (29%) with such components. The considered need for subdural (SD) EEG lowered SF outcome from 18 (90%) of 20 patients without SD to 8 (24%) of 33 with SD; this likely reflected an insufficient congruity of ictal semiology and interictal and ictal scalp EEG for localising epileptogenesis. Within this SD group, ictal origin from the later resected lobe, determined by two measures of such congruency, increased SF outcome from 12-14% to 40-46%.
CONCLUSIONS: Scalp EEG may help determine which non-lesional patients will benefit from resective surgery.
[Supported by: Dr. Warren Thomas Blume.]