Abstracts

Rationale: Corpus callosotomy (CC) has been well established as a palliative procedure in intractable pediatric epilepsy patients with predominantly astatic seizures. However, there have been conflicting reports regarding whether corpus callosotomy can achieve localization of seizure foci by preventing rapid secondary generalization without leaving long-term neurological deficit. The purpose of this study is to assess the safety and efficacy of corpus callosotomy as a localization tool in patients with catastrophic unlocalizing epilepsy. Methods: We reviewed the medical records of 43 patients (age range 0.5-28 years; M 23 F 20) who underwent CC for treatment of astatic seizures at Florida Hospital for Children from July 2011 till December 2013. All of the patients had tailored pre-surgical evaluation employing MRI, scalp EEG, FDG-PET, SPECT, and MEG; had unlocalizing or discordant localization tests; and had quite disabling tonic/atonic seizures affecting cognitive development and quality of life. Patients were re-evaluated for seizure localization and lateralization at 1-6 months post-CC. Results: Thirty six (84%) children (< 18 yrs old) and seven (16%) adults underwent complete corpus callosotomy. All of the patients had tonic or atonic seizures as the main seizure type. Twenty eight (65%) patients had underlying structural-metabolic; 3 patient with genetic; and 12 patients with unknown etiology. Following CC, six (14%) patients became seizure-free (ILAE 1). Five (11 %) patients underwent additional resective surgery following CC and became seizure-free. Overall, 15 (34%) patients achieved seizure outcome with ILAE 1 and 2. None of the patients experienced worsening of seizure. In 19 (37%) patients, seizures became lateralizing or localizing after CC. Among 19 patients, 17 patients underwent additional resective surgery: 8 with functional hemispherectomy; and 9 with lobectomy or cortisectomy. Favorable seizure outcome with ILAE class 1 or 2 was achieved in 7 (41%) patients who underwent resective surgery following corpus callosotomy. Acute disconnection syndrome was observed in 4 patients (1 child 3 adults) with eventual recovery in all patients. Conclusions: Our data showed that complete corpus callosotomy not only provide an effective treatment for astatic seizures, but also lateralization or localization information for further respective surgery in as many as 1/3^rd of the patients with catastrophic unlocalizing epilepsy. None of the patients suffered from permanent disabling neurological deficits after the procedure. Further study may be necessary to understand which patient characteristics favor post-CC lateralization.