Operative results without invasive monitoring in patients with frontal lobe epileptogenic lesions

Purpose: To further explore the still controversial issues regarding whethe r all or most candidates for epilepsy surgery should be investigated preope ratively with invasive long-term video-EEG monitoring techniques (ILTVE). Methods: We studied five patients with intractable seizures since early chi ldhood using the same protocol: clinical evaluation, magnetic resonance ima ging (MRI) with fluid-attenuated inversion recovery (FLAIR) sequences, long -term video-EEG (LTVE) monitoring with scalp electroencephalogram (EEG), in terictal single photon emission computed tomography (SPECT), positron emiss ion tomography (PET), and neuropsychological testing. The patients' seizure s had clinical features suggesting a frontal lobe (FL) origin. MRI scans re vealed focal cortical dysplasia (CD) in four patients and a probable glioti c lesion in the fifth. The findings in both PET and SPECT images were congr uent with those of the MRI. Scalp LTVE failed to localize the ictal onset, although the data exhibited features suggestive of both CDs and FL seizures . On the basis of these results, surgery was performed with intraoperative corticography, and the cortical area exhibiting the greatest degree of spik ing was ablated. Results: Histopathologic study of four of the resected specimens confirmed the presence of CD, whereas in the fifth, there were features consistent wi th a remote encephaloclastic lesion. There were no postoperative deficits. Seizures in three of the patients were completely controlled at 2-3.5 years of follow-up:, a fourth patient is still having a few seizures. which have required reinstitution of pharmacotherapy, and the fifth has obtained > 70 %, control. All patients have had significant improvement in psychosocial m easures. For comparison, five patients with generally similar clinical and neuroradiologic features to the previous group underwent preoperative ILTVE monitoring. The surgical outcomes between the two groups have not differed significantly. Conclusions: We conclude that patients with FL epilepsies may be able to un dergo successful surgery Without preoperative ILTVE monitoring, provided th ere is high concordance between neuroimaging tests (MRI. SPECT, PET) and th e seizure phenotypes, even when routine EEGs and scalp LVTE fail to localiz e ictal onset unambiguously. The surgical outcomes of these patients genera lly paralleled those of the other subjects who also had FL epilepsy but who were operated on only after standard ILTVE monitoring.