Abstracts

Rationale: Surgical division of the corpus callosum for the treatment of seizures was introduced by VanWagenen and Herren in 1940. Several years later Luessenhop reported a small clinical series with excellent results. Since then corpus callosotomy (CC) gained popularity among epilepsy surgeons as surgical techniques were improving and surgeons experience with this method was growing. It is generally accepted today that CC constitutes a palliative surgical option for patients suffering medically refractory epilepsy characterized by drop attacks or major, generalized motor seizures. In our current communication we present our long-term outcome data from a series of patients undergoing anterior or complete callosotomy.Methods: During a 20-year period (1985-2005) a total of 140 patients underwent anterior (110 patients, 78.6%) or complete (30 patients, 21.4%) CC. The indications were: generalized tonic-clonic seizures (47 patients, 33.6%), tonic seizures (20 patients, 14.3%), atonic seizures (29 patients, 20.7%), simple or complex partial seizures (18 patients, 12.9%), absence seizures (16 patients, 11.4%), and myoclonic seizures (10 patients, 7.1%). The preoperative evaluation of all our patients included detailed neurological examination, ictal and inter-ictal surface EEG and video-EEG monitoring, CT and/or MRI studies, and neuropsychological evaluation. In selected cases ictal Spect and SISCOM studies, PET scan, proton MR Spectroscopy, Magnetic Source Imaging, and invasive monitoring with stereotactically implanted depth and/or subdural grid/strip electrodes were also employed. Engel’s classification system was utilized for postoperative outcome evaluation in our series. The mean follow-up time in our series was 9.6 years (range: 3-17 years, median: 5 years).Results: Our surgical outcome was evaluated at 1 and then at 5 years post-operatively. Our comparative results for anterior and complete CC are summarized in Tables 1 (anterior CC) and 2 (complete CC). Follow-up data were available for 80 patients undergoing anterior CC and 18 patients undergoing complete CC at the completion of five years postoperatively. The intraoperative and postoperative cumulative complication rate for anterior CC was 4.5% (5/110 patients) including the development of a mild disconnection syndrome (1case), sensory deficit (1 case), respiratory infection (1 case), thrombophlebitis (1 case), and osteomyelitis (1 case). Contrariwise, the complication rate among patients undergoing complete CC was 20% (6/30 patients) including the development of disconnection syndrome (4 cases), early postoperative central herniation (1 case), and respiratory infection (1 case).Conclusions: Corpus callosotomy constitutes a safe surgical procedure for the treatment of patients with medically refractory atonic, absence or rapidly spreading motor seizures. The long-term follow up of these patients revealed no delayed undesired effects while the initially obtained surgical outcome remained stable in our series.