"Subtotal" hemispherectomy in children with intractable focal epilepsy
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Harry T Chugani1, Eishi Asano, Csaba Juhász
1Department of Pediatrics, Wayne State University School of Medicine, Children's Hospital of Michigan, Detroit Medical Center, Detroit, Michigan, U.S.A; Department of Neurology, Wayne State University School of Medicine, Children's Hospital of Michigan, Detroit Medical Center, Detroit, Michigan, U.S.A.
Insights
Subtotal hemispherectomy in children, sparing sensorimotor cortex, offers excellent seizure control. This epilepsy surgery approach can avoid complete hemispherectomy, even with widespread abnormalities, especially when hemiparesis is minimal.
Area of Science:
- Pediatric Neurosurgery
- Epilepsy Surgery
- Clinical Neurology
Background:
- Pediatric epilepsy surgery often requires larger resections than in adults due to underlying pathology.
- Unilateral multifocal seizure onsets can involve large portions of a hemisphere in children.
- Hemispherectomy is considered for significant hemiparesis, but sparing sensorimotor cortex is preferred otherwise.
Purpose of the Study:
- To evaluate the efficacy of "subtotal" hemispherectomy in children with epilepsy.
- To determine seizure control outcomes in pediatric patients undergoing extensive unilateral resections that spare the primary sensorimotor cortex.
Main Methods:
- A cohort of 23 children (ages 1.3 to 14.2 years) underwent "subtotal" hemispherectomy between 2001 and 2013.
- Pre-operative evaluations included video-electroencephalography (EEG), magnetic resonance imaging (MRI), and F-fluorodeoxyglucose-positron emission tomography (FDG-PET).
- Surgical extent was guided by subdural electrocorticography (ECoG), with outcomes classified by the International League Against Epilepsy (ILAE).
Main Results:
- Seventeen out of 23 patients (74%) achieved ILAE Class 1 seizure control.
- The most common seizure type was epileptic spasms (11 patients).
- Histopathology revealed various malformations in 9 subjects, with the remainder showing gliosis or other abnormalities.
Conclusions:
- Extensive unilateral cortical resections that preserve sensorimotor cortex yield excellent seizure control in pediatric epilepsy.
- Complete hemispherectomy can often be avoided in children with widespread unilateral epileptogenicity or imaging abnormalities.
- This approach is particularly beneficial when significant hemiparesis is absent.
Objective:
Cortical resections in epilepsy surgery tend to be larger in children, compared to adults, partly due to underlying pathology. Some children show unilateral multifocal seizure onsets involving much of the hemisphere. If there were a significant hemiparesis present, hemispherectomy would be the procedure of choice. Otherwise, it is preferable to spare the primary sensorimotor cortex. We report the results of "subtotal" hemispherectomy in 23 children.
Methods:
All children (ages 1 year and 4 months to 14 years and 2 months) were operated on between 2001 and 2013 at Children's Hospital of Michigan (Detroit). Patients were evaluated with scalp video-electroencephalography (EEG), magnetic resonance imaging (MRI), (18) F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scans, and neuropsychological assessments when applicable. Subsequently, each case was discussed in a multidisciplinary epilepsy surgery conference, and a consensus was reached pertaining to candidacy for surgery and optimum surgical approach. The actual extent of resection was based on the results from subdural electrocorticography (ECoG) monitoring. The surgical outcome is based on International League Against Epilepsy (ILAE) classification (class 1-6).
Results:
Among the 23 patients, 11 had epileptic spasms as their major seizure type; these were associated with focal seizures in 3 children. MRI showed focal abnormalities in 12 children. FDG-PET was abnormal in all but one subject. All except two children underwent chronic subdural ECoG. Multiple subpial transections were performed over the sensorimotor cortex in three subjects. On histopathology, various malformations were seen in 9 subjects; the remainder showed gliosis alone (n = 12), porencephaly (n = 1), and gliosis with microglial activation (n = 1). Follow-up ranged from 13 to 157 months (mean = 65 months). Outcomes consisted of class 1 (n = 17, 74%), class 2 (n = 2), class 3 (n = 1), class 4 (n = 1), and class 5 (n = 2).
Significance:
Extensive unilateral resections sparing only sensorimotor cortex can be performed with excellent results in seizure control. Even with the presence of widespread unilateral epileptogenicity or anatomic/functional imaging abnormalities, complete hemispherectomy can often be avoided, particularly when there is little hemiparesis.