gms | German Medical Science

Objective: Hemispherotomy has proven to be an effective treatment modality for unilateral hemispheric epilepsy. The patients present with extensive brain lesions associated with neurological deficits and an early onset of catastrophic epilepsy. Traditionally, the decision to proceed to surgical treatment is based on unilateral electroencephalographic findings and magnetic resonance imaging with patients usually showing hemiparesis.

Methods: The records of 29 pediatric and 8 adult patients who underwent hemispherotomy between 1999–2009 were retrospectively analyzed. Etiologies included focal cortical dysplasias in five cases, hemimegalencephaly in four, hypoxic-ischemic lesions in 22, Rasmussen encephalitis in five and infection in three cases. Thirty-one patients had congenital or early-acquired brain lesions, while four patients were older than 4 years of age at epilepsy manifestation and diagnosis. Patients had daily seizures with loss of consciousness, falls, or frequent status epilepticus. Duration of epilepsy prior to surgery varied from eight months to 36.5 years. In five patients, hemispherotomy was performed following unsuccessful previous procedures. Follow-up ranged from six months to almost ten years.

Results: Postoperative complications included hydrocephalus with shunt placement in six patients and three had meningitis. No cases of incomplete disconnection were noted. In our cohort, seizure recurrence was associated with pathologies such as hemimegalencephaly and Rasmussen encephalitis. Bilateral magnetic resonance imaging pathology correlated with poor outcome, and patients with hypoxic-ischemic insults were the ones to benefit most regarding both seizure freedom and developmental outcome. Bilateral electroencephalographic findings preoperatively did not preclude seizure freedom. Seizure recurrence was noted after two-year-follow-up in two cases.

Conclusions: Hemispherotomy has proven to be a reliable surgical procedure for the reduction of seizure burden. Outcome depends on etiology, as previously reported, but even seizure reduction may be crucial in some cases, especially regarding severe or disabling seizure types. Early intervention may be essential in order to improve developmental outcome. The selection of candidates more likely to benefit from hemispherotomy and the appropriate time point for such a procedure constitutes a major challenge in current epilepsy surgery.