Seizure Outcome and Memory Function after Multiple Hippocampal Transections (IN5-1.009)

Abstract

Objective: To evaluate seizure outcome and memory function after multiple hippocampal transections (MHT) of the hippocampus in intractable nonlesional mesial temporal lobe epilepsy (MTLE). Background Hippocampal anatomy suggests that the circuits of memory processing (transverse lamellae) are different from those of seizure propagation (longitudinal pathways). Thus, transverse cuts may interrupt seizure circuitry without interfering with memory function. Design/Methods: 13 patients with nonlesional MTLE had depth electrode recordings confirming hippocampal seizure onset and underwent MHT. Duration of epilepsy ranged between 5 and 55 years. Antiepileptic drugs (AEDs) were not changed postoperatively. Intraoperative monitoring was done with 5-6 hippocampal electrodes spaced at around 1 cm intervals, and spike counting for approximately 10 minutes before each cut. The number of transections ranged between 4 and 7 resulting in marked spike reduction (p=0.003, paired t-test). Neuropsychological assessment was done preoperatively and 1 year postoperatively in all patients. Results: There were no complications. 10 patients (77%) are seizure-free (follow-up>1 year in 8 patients, and 0.3). Conclusions: MHT provides an effective intervention and a safer alternative than temporal lobectomy regarding memory preservation in patients with nonlesional MTLE. Disclosure: Dr. Kahriman has nothing to disclose. Dr. Miller has nothing to disclose. Dr. Macinuas has nothing to disclose. Dr. Bailey has nothing to disclose. Dr. Fastenau has nothing to disclose. Dr. Syed has nothing to disclose. Dr. Amina has nothing to disclose. Dr. Tanner has received personal compensation for activities with GlaxoSmithKline, Inc. as a speaker. Dr. Karanec has nothing to disclose. Dr. Luders has nothing to disclose. Dr. Koubeissi has received personal compensation for activities with UCB Pharma and Pfizer Inc as a speaker.