Extratemporal, nonlesional epilepsy in children: postsurgical clinical and neurocognitive outcomes.

Pediatric Epilepsy Center, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, Missouri 63110-1002, USA.
Journal of Neurosurgery Pediatrics (Impact Factor: 1.63). 02/2011; 7(2):179-88. DOI: 10.3171/2010.11.PEDS10265
Source: PubMed

ABSTRACT Patients undergoing epilepsy surgery without evidence of a lesion on MR imaging and without a temporal source for seizure onset generally have less favorable outcomes than patients with structural lesions or temporal onset. However, many of these patients are viable candidates for invasive monitoring and subsequent resection or multiple subpial transections (MSTs). The purpose of this study was to evaluate the surgical treatment of pediatric patients with extratemporal, nonlesional epilepsy in order to better understand the clinical and neuropsychological outcomes expected in this patient group.
Forty-three pediatric patients with negative results on MR imaging and lateralized, extratemporal findings on electroencephalography underwent invasive monitoring with grid and/or strip electrodes. Thirty-three subsequently had resection of an epileptogenic focus and/or MSTs.
Outcome was classified as Engel class I or II in 54.5% of the patients who underwent resection/MSTs and Engel class III or IV in 45.5%. Use of MSTs was associated with poor outcome. Neuropsychological evaluation showed significant improvement in immediate auditory attention following surgery and revealed several significant results on subgroup analysis. Complications occurred in 14% of patients (a 7% rate per procedure). Ten patients (23%) underwent invasive monitoring without proceeding to therapeutic surgery because no epileptogenic region was amenable to resection. Neuropsychological outcomes were generally stable.
Patients with extratemporal, nonlesional seizures are viable candidates for invasive monitoring with grid/strip electrodes, and good outcomes can be obtained with resective surgery. The use of MSTs may correlate with worse outcome. This study also provides additional data to assist in counseling patients on the risks of negative invasive monitoring, deficits resulting from resection/MSTs, and possible operative complications.

  • [Show abstract] [Hide abstract]
    ABSTRACT: In adults, resection of the medial frontal lobe has been shown to result in supplementary motor area (SMA) syndrome, a disorder characterized by transient motor impairment. Studies examining the development of SMA syndrome in children, however, are wanting. To characterize the development of SMA syndrome and to analyze seizure outcomes after surgery in the medial frontal lobe for medically intractable epilepsy. Thirty-nine patients with medically intractable epilepsy who underwent surgery in the medial frontal lobe were reviewed retrospectively. The progression of neurological impairment and seizure outcome after surgery was recorded, and the extent of cortex resected was analyzed. After resection in the region of the SMA, 23 patients (59%) developed postoperative neurological impairment; 17 (74%) were identified as SMA syndrome. No neurological impairment was found after surgery in 16 patients (41%). Six patients (15%) experienced permanent neurological impairment. The majority of patients (82%) who developed SMA syndrome had resolution of their symptoms by 1 month postoperatively. Preoperative magnetic resonance imaging finding of lesional cases was associated with a significantly decreased likelihood of developing SMA syndrome (P = .02). Seizure outcome was favorable after surgery in most patients. Surgery for medically intractable epilepsy in the region of the medial frontal cortex is effective and associated with reversible neurological impairment in children. All patients had resolution of their SMA syndrome by 6 months postoperatively.
    Neurosurgery 11/2011; 70(5):1152-68; discussion 1168. · 2.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IMPORTANCE A focal lesion detected by use of magnetic resonance imaging (MRI) is a favorable prognostic finding for epilepsy surgery. Patients with normal MRI findings and extratemporal lobe epilepsy have less favorable outcomes. Most studies investigating the outcomes of patients with normal MRI findings who underwent (nonlesional) extratemporal epilepsy surgery are confined to a highly select group of patients with limited follow-up. OBJECTIVE To evaluate noninvasive diagnostic test results and their association with excellent surgical outcomes (defined using Engel classes I-IIA of surgical outcomes) in a group of patients with medically resistant nonlesional extratemporal epilepsy. DESIGN A retrospective study. SETTING Mayo Clinic, Rochester, Minnesota. PARTICIPANTS From 1997 through 2002, we identified 85 patients with medically resistant extratemporal lobe epilepsy who had normal MRI findings. Based on a standardized presurgical evaluation and review at a multidisciplinary epilepsy surgery conference, some of these patients were selected for intracranial electroencephalographic (EEG) monitoring and epilepsy surgery. EXPOSURE Nonlesional extratemporal lobe epilepsy surgery. MAIN OUTCOMES AND MEASURES The results of noninvasive diagnostic tests and the clinical variables potentially associated with excellent surgical outcome were examined in patients with a minimum follow-up of 1 year (mean follow-up, 9 years). RESULTS Based on the noninvasive diagnostic test results, a clear hypothesis for seizure origin was possible for 47 of the 85 patients (55%), and 31 of these 47 patients (66%) proceeded to intracranial EEG monitoring. For 24 of these 31 patients undergoing long-term intracranial EEG (77%), a seizure focus was identified and surgically resected. Of these 24 patients, 9 (38%) had an excellent outcome after resective epilepsy surgery. All patients with an excellent surgical outcome had at least 10 years of follow-up. Univariate analysis showed that localized interictal epileptiform discharges on scalp EEGs were associated with an excellent surgical outcome. CONCLUSIONS AND RELEVANCE Scalp EEG was the most useful test for identifying patients with normal MRI findings and extratemporal lobe epilepsy who were likely to have excellent outcomes after epilepsy surgery. Extending outcome analysis beyond the resective surgery group to the entire group of patients who were evaluated further highlights the challenge that these patients pose. Although 9 of 24 patients undergoing resective surgery (38%) had excellent outcomes, only 9 of 31 patients undergoing intracranial EEG (29%) and only 9 of 85 patient with nonlesional extratemporal lobe epilepsy (11%) had long-term excellent outcomes.
    JAMA neurology. 06/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: MRI is one of the most important diagnostic tools in the presurgical evaluation of patients suffering from pharmaco-refractory focal epilepsies. Presence of a lesion on MRI influences both diagnostic classification as well as selection for surgery; however, the implications for MRI-negative cases are far from well defined for such patients. Detection of potentially epileptogenic lesions depends on the techniques applied (high-field MRI, post-processing, etc.) and the experience of the neuroradiologist. The proportion of MRI-negative patients in reported epilepsy surgery cohorts ranges from 16 to 47%. Most MRI-negative patients undergo invasive long-term EEG recordings before a final decision regarding resection is possible. Post-operative seizure freedom rates, with few exceptions, range from 40 to 50%. Selection of surgical candidates and post-operative outcomes may be improved by recent developments in structural and functional imaging techniques and multimodal approaches. This report gives an overview of outcomes after epilepsy surgery in MR-negative patients with a focus on children. Issues regarding definitions, the role of established and recently introduced diagnostic tools, and the question of how outcome might be improved in the future are discussed.
    Epileptic disorders: international epilepsy journal with videotape 06/2013; · 1.17 Impact Factor


Available from
Jun 13, 2014