223. Multiple Hippocampal Transections: A Meta-analysis of Post-Operative Memory Outcome and Seizure Control

Authors: Nebras M. Warsi, MD, CM; Grace Thiong'O, MD; Jeff Zuccato, MD; George Ibrahim, MD (Toronto, Canada)

Introduction:

Temporal lobectomy with amygdalohippocampectomy is the standard surgical treatment for appropriate candidates with medically-intractable temporal lobe epilepsy. More recently, due to the risk of post-operative language/memory decline in a subset of patients with intact memory, a multiple hippocampal transection (MHT) approach has been proposed to preserve function.

Methods:

Studies of MHT reporting both Engel and verbal memory outcome measures were included in accordance with PRISMA guidelines for reporting of systematic reviews and meta-analyses. Data were extracted on verbal memory function pre- and post-operatively, seizure outcome, and demographic factors. A random effect model was used to determine overall verbal memory function after MHT and a meta-regression model was applied to identify factors associated with outcome.

Results:

A total of 114 patients across five studies were included. Engel class I seizure outcome across all studies ranged from 64.7% to 94.7%, with 84 of the 114 patients achieving this outcome. Preoperative verbal memory score was most strongly associated factor for postoperative verbal memory preservation (p=0.003). Of 59 patients with full verbal memory outcome scores 86.8% (95%CI: 77.6%-96%) had complete preservation of verbal memory relative to pre-operative functional baseline.

Conclusion:

MHT is an evolving surgical technique. Although the present data are limited, the current meta-analysis suggests that this approach is effective at preserving verbal memory in patients with good baseline function. Rates of seizure control are comparable to those achieved through mesial temporal resection for dominant temporal lobe epilepsy.