Successful surgery for epilepsy due to early brain lesions despite generalized EEG findings.

OBJECTIVE: To understand the role of epilepsy surgery in children with generalized or bilateral findings on preoperative scalp EEG. METHODS: From our pediatric epilepsy surgery series, we identified 50 patients in whom 30 to 100% of preoperative epileptiform discharges (ictal, interictal, or both) were generalized or contralateral to the side of surgery. RESULTS: All patients had severe refractory epilepsy and an epileptogenic lesion on brain MRI. Ninety percent of the lesions were congenital, perinatal, or acquired during infancy, predominantly malformations of cortical development (44%) or cystic encephalomalacia (40%). Age at surgery was 0.2 to 24 (median 7.7) years. Surgeries were hemispherectomy (64%) or lobar or multilobar resection. At last follow-up (median 24.0 months), 72% of patients were seizure-free, 16% had marked improvement with only brief episodes of staring or tonic stiffening, and 12% were not improved. The rate of seizure-free outcome was not significantly associated with age at seizure onset or surgery, presence of hemiparesis or focal clinical features during seizures, type of lesion, or surgery type. Postoperative seizure-free rate did not differ from that in a comparison group of similar patients who matched the study group except for their high percentage (70 to 100%) of ipsilateral ictal and interictal epileptiform discharges on preoperative EEG. CONCLUSIONS: Epilepsy surgery may be successful for selected children and adolescents with a congenital or early-acquired brain lesion, despite abundant generalized or bilateral epileptiform discharges on EEG. The diffuse EEG expression may be due to an interaction between the early lesion and the developing brain.

Postoperative seizures after extratemporal resections and hemispherectomy in pediatric epilepsy.

OBJECTIVES: To estimate frequency and risk factors for acute postoperative seizures (APOS) within the first week after extratemporal cortical resection (ETR) and hemispherectomy (HS) in children and to assess the predictive value of APOS on long-term seizure outcome in this group. METHODS: The authors conducted a retrospective analysis of children (< 18 years), who underwent ETR or HS for intractable epilepsy between 1995 and 2002. APOS features and seizure outcome after ETR or HS were obtained at 6, 12, and 24 months. Univariate logistic regression was used for risk factors of APOS and life table analysis and log rank tests for seizure outcome at 0 to 6, 6 to 12, and 12 to 24 months. RESULTS: Of 132 patients, 34 (26%) had APOS. APOS were more frequent after ETR (26/71) than HS (8/61) (p < 0.01). APOS, irrespective of their timing, number, semiology, or other perioperative complications, were an independent predictor of poor postoperative seizure outcome at 2 years (p < 0.001). The estimated odds of postoperative Engel class I outcome in the APOS vs non-APOS categories was 0.27 (73% less likely) for 0- to 6-month, 0.22 (78% less likely) for 6- to 12-month, and 0.13 (87% less likely) for the 12- to 24-month intervals. CONCLUSIONS: Acute postoperative seizures (APOS) occur in 26% children, and the risk is higher after extratemporal cortical resection than hemispherectomy. APOS predict a poor postoperative seizure outcome at 6, 12, and 24 months. This study is useful for counseling families after epilepsy surgery. It also suggests that APOS may not be discounted as "benign" in research studies that evaluate seizure outcomes after epilepsy surgery.

Identification of candidates for epilepsy surgery in patients with tuberous sclerosis.

The authors reviewed preoperative MRI and EEG findings in relation to postsurgical outcome in 17 patients with refractory epilepsy due to tuberous sclerosis complex (TSC). Resecting concordant MRI (main tuber) and EEG abnormalities offered seizure freedom (8/9, 89%; median follow-up 25 months) comparable to other focal etiologies. Patients with nonconcordant MRI and EEG findings did less well (3/8, 38%, seizure free; p = 0.027, OR = 13).

Seizure outcome after epilepsy surgery in patients with normal preoperative MRI.

OBJECTIVE: To determine outcome after epilepsy surgery in patients with normal preoperative magnetic resonance imaging (MRI). METHODS: 24 adult and paediatric patients with normal preoperative MRIs were studied. They underwent epilepsy surgery between 1994 and 2001 and had at least one year of follow up. RESULTS: At the most recent follow up, nine patients (37%) were seizure-free and 18 (75%) had at least a 90% reduction in seizure frequency with weekly or monthly seizures. Seizure freedom was not significantly different after resections in frontal (5/9) or temporal regions (4/13) (p = 0.24, Fisher's exact test), or among patients with or without localising features on EEG, PET, or ictal SPECT. Subdural grids, used in 15 of 24 patients, helped tailor resections but were not associated with differences in outcome. Histopathology showed cortical dysplasia in 10 patients (42%), non-specific findings in 13 (54%), and hippocampal sclerosis in one (4%). Cortical dysplasia was seen in seven patients with frontal resection (78%) and non-specific findings in nine (69%) with temporal resection. Seizure outcome did not differ on the basis of location of resection or histopathology. CONCLUSIONS: While these results were less favourable than expected for patients with focal epileptogenic lesions seen on MRI, they represented worthwhile improvement for this patient population with high preoperative seizure burden. In this highly selected group, no single test or combination of tests further predicted postoperative seizure outcome.

Resective surgery to treat refractory status epilepticus in children with focal epileptogenesis.

Prolonged high-dose suppressive therapy (HDST) is a mainstay in the management of refractory status epilepticus (RSE), albeit with high morbidity and mortality. The authors studied 10 patients who were carefully selected for epilepsy surgery after failing prolonged (>2 weeks) HDST. Status epilepticus was stopped acutely in all of them with no mortality and no substantial morbidity. At follow-up (median 7 months), 7 (70%) of 10 patients were seizure free, and 3 (30%) of 10 had significant improvement in their epilepsy.