Hemispherectomy For Intractable Epilepsy in Adults: The First Reported Series

Shearwood McClelland III M.D., Robert E. Maxwell M.D., Ph.D.

Department of Neurosurgery, University of Minnesota Medical School, Minneapolis, MN

Introduction:

The indications, efficacy and long-term morbidity of hemispherectomy for intractable unihemispheric epilepsy (IUE) have long been established in pediatric patients. However, because of the decreased plasticity of the adult brain, the potential morbidity associated with hemispheric removal has traditionally served as a contraindication for hemispherectomy in adult patients, with only isolated case reports present in the literature. This study reports the first series examining hemispherectomy exclusively in adult patients (minimum 18 years old), detailing long-term morbidity and seizure outcomes.

Methods:

Nine adults (6F/3M) with IUE underwent hemispherectomy (5R/4L) at our institution over a 49-year period. All patients chosen had medically refractory seizures associated with unilateral hemiplegia and visual field loss. Mean age was 28.1 years (range=19-38), and mean epilepsy duration was 22.2 years (range=12-34). The most common seizure etiologies were birth trauma and encephalitis.

Results:

Average follow-up was 21 years (range=0.8-38). Using a modified Engel outcome scale, 5 patients (55.6 percent) were class I, 2 were class II, none were class III, and 2 were class IV (less than 75 percent improvement) at last follow-up. Six patients had more than 30 years of follow-up, of whom 5 (83.3 percent) were class IA (one was class IIA). Morbidity (2 patients) consisted of one bone flap infection and epidural abscess complicated by a permanent dysphasia, and one worsening of preoperative hemiparesis. There were no cases of surgery-related mortality, hydrocephalus, or superficial cerebral hemosiderosis.

Conclusion:

Hemispherectomy is an effective procedure in appropriately selected adult patients, resulting in excellent long-term seizure control, minimal long-term morbidity and no mortality.

Keywords:

Hemispherectomy, Adult, Intractable Unihemispheric Epilepsy, Long-Term Seizure Control