Selective Posterior Callosotomy in Sitting Position for Patients with Medically Refractory Generalized Epilepsy – Operative Technique, Safety, and Efficacy

Introduction: Callosotomy is a well-validated surgical procedure to ameliorate drop attacks; however, disconnection syndrome is a known complication. Reports suggest selective posterior callosotomy may decrease this complication rate. We hypothesize that selective posterior callosotomy in the sitting position could be safely performed to control motor symptoms in medically refractory generalized epilepsy.

Methods: We present an institutional case series (10) for the treatment of generalized epilepsy and drop attacks (2020-2022). Posterior callosotomy was used to complete prior anterior callosotomy or primary sectioning of posterior fibers. The patient is placed in the sitting position to permit easy access to the splenium. A right occipital craniotomy is performed with exposure of the transverse and sagittal sinuses. After visualization of the galenic venous complex, the splenium and corpus callosum are sectioned until the lateral ventricle is visualized inferiorly, pericallosal arteries superiorly, and rostrum anteriorly. Clinical outcomes were retrospectively collected and analyzed.

Results: Ten patients (7 males, 18-36 years) underwent posterior callosotomy. Median monthly drop attacks and other seizure semiologies decreased from 56 to 0 and 98 to 1 respectively at a median follow-up of 4.25 (IQR 1.4-11.25) months. Operative time averaged 161±50.9 minutes, blood loss averaged 93±61 ml, and median hospitalization was 6.5 (IQR 6.5-16) days. No intraoperative complications or readmissions were encountered. Six patients were discharged home and 4 to inpatient rehab. Postoperative functional changes of somnolence (3) and altered mental status (2) were resolved prior to discharge; dysphagia (2) and left-sided weakness (1) were resolved during inpatient rehab. In all patients, significant reduction of motor seizures (mainly drop attacks) was achieved.

Conclusion : This novel technique in the sitting position permits facile exposure and sectioning of the posterior 2/3 of the corpus callosum. The technique is safe and effective in this series and may have great utility in managing patients with drug-resistant generalized epilepsy with drop attacks.