Corpus Callosotomy for Treatment-resistant Poorly Localized Epilepsy in Adult Patients

Introduction: In medically-refractory epilepsy, surgical treatment of the epileptogenic focus frequently yields seizure freedom. However, bilateral, poorly localized, or surgically refractory epilepsy requires another solution. Corpus callosotomy has been shown to reduce seizure frequency in pediatric patients with treatment-refractory epilepsy in primarily retrospective series and cohort studies. However, few studies have demonstrated its efficacy in adults. Here, we present six adult cases of refractory epilepsy treated with corpus callosotomy at a single institution.

Methods: After obtaining Institutional Review Board (IRB) approval, operative records of one surgeon from 2014 to 2022 were searched comprehensively for individuals >18 years of age with refractory epilepsy treated with craniotomy for corpus callosotomy. Data were extracted on patient demographics, pre- and post-operative symptoms, imaging, electroencephalography (EEG) findings, and complications.

Results: Six patients underwent corpus callosotomy for treatment-refractory epilepsy (Table 1). Average age at time of operation was 30.8 years (range 22-44), most common etiology was idiopathic (50%), and all patients had non-lateralized epileptogenic foci (Table 2). All patients suffered from generalized tonic-clonic seizures, while three had atonic seizures (50%). Most patients (83.3%) had abnormal pre-operative magnetic resonance imaging (MRI), and most underwent anterior two-thirds callosotomy (66.7%). All patients initially had >80% reduction in seizure frequency. Three patients had fewer anti-epileptic needs post-operatively. Two major complications occurred (33.3%). There was one surgical site infection requiring washout, and one venous infarct. Minor complications included dissociation syndromes in three patients and one case of aseptic meningitis (Table 3).

Conclusion : Although previous work has suggested inferior results with corpus callosotomy in adults compared to children, this small case series suggests that callosotomy may be effective for poorly localized refractory epilepsy in adults. Care must be taken to avoid complications; stereotactic radiosurgery or laser-interstitial thermal therapy represent two novel modalities to achieve similar outcomes with fewer complications.