Abstracts

Rationale: Hemispherectomy is a surgical technique that is commonly used in drug-resistant epilepsies. It is well-established to be successful treating pediatric patients with unilateral hemispheric lesions. Despite some reports of successful use in adults, it still remains an underutilized procedure. We retrospectively evaluated the clinical outcomes after hemispherectomy in adult patients with refractory epilepsy. Methods: A retrospective chart review identified 6 patients. The etiology of seizures was perinatal stroke in 5 patients and presumed post-viral encephalitis in 1 patient. All patients had varying degrees of hemiparesis and visual field abnormalities, but were ambulatory at baseline. Preoperative EEG and MRI were completed in all patients. Neuropsychological testing was obtained in 4 out of 6 patients. Two patients had a pre-surgical PET scan, and 1 had fMRI. Five patients underwent functional hemispherectomy, and 1 patient had an anatomical hemispherectomy. Equal numbers had right- and left-hemispheric lesions. Literature review of hemispherectomies was performed using MEDLINE/PubMED. Case series of patients older than 18 years were included; reports of patients without clear follow up duration or method of validated seizure outcome quantification were excluded. Seizure outcome was based on the Engel classification scheme. Results: Postoperatively, 4 out of 6 patients were seizure-free at follow up, spanning 3 to 34 months. One patient had an Engel class II outcome after 2 years, and 1 patient had greater than 70% seizure reduction. One patient reported postoperative headaches. One patient complained of mild orthostasis at 3-month follow up, with subsequent resolution. None of the patients experienced any worsening in neurological status, and 2 reported improvement in motor and language function. None of the patients required placement of a shunt. A total of 89 cases of adult hemispherectomy were identified in literature including 6 case series and our unpublished series. Sixty-four patients underwent functional hemispherectomy; twenty-five patients had anatomic hemispherectomy. Length of follow-up ranged from 2 to 234 months. Seizure freedom was reported in 83.1% of patients. In the literature, objective improvement of cognitive and motor function has been reported in over 80% of patients, when all age groups were considered. None of the patients had significant neurological decline. Worsening hemiparesis was reported in 2 patients without compromise in ambulatory ability. Conclusions: Hemispherectomy is a valuable surgical tool for adult patients with intractable epilepsy. In published cases, the procedure has been well tolerated without significant morbidity. The level of motor and cognitive improvement is likely accounted for by decrease in seizure frequency and reduction of anti-epileptic therapy adverse effects. Removal of diseased brain may additionally reduce spasticity and, in turn, improve ambulation.