Abstracts

Rationale: There is a single randomized clinical trial (RCT) on amount of hippocampal resection, seizure-freedom and memory decline in the treatment of mesial temporal lobe epilepsy (MTLE). It suggested that more is better and does not more adversely affect memory (1). Another non-randomized trial (2) suggested to "tailor" resection to intraoperative epileptic activity on ECoG to minimize memory decline. What impact do these small trials have on surgeons' approach to hippocampal resection? What are surgeons' perceptions of the effects of greater resection on chances of seizure-freedom and memory loss? Is it time for a larger clinical trial to address this knowledge gap? Methods: An online survey was designed and sent to >200 surgeon email addresses to examine the factors that guide surgical approach to extent of hippocampal resection and attitudes towards the relationship of amount of resection to seizure-freedom and memory decline in patients with mesial temporal sclerosis (MTS) and MTLE. Results: Responses have so far been received from 55 individuals, of whom 47 are in academic practice, 5 in private practice and 2 no-response. 78% of respondents either routinely or if possible resect to the tectal plate or >3.5cm, 56% doing so routinely, whereas 22% resect to the cerebral peduncle or <=3cm if possible, 15% doing so routinely. 29% alter their resection based on various factors, such as dominance. 15% utilize intraoperative hippocampal ECoG to tailor resection. 89% believe amount of resection affects seizure freedom and 35% believe amount affects memory performance. Conclusions: With the caveat that assessing such a complex topic is difficult with a practical survey, it appears that while most surgeons maximize hippocampal resection to maximize seizure-free outcome, a substantial percentage believe that sparing hippocampus minimizes memory loss. Clearly much more research on clinical outcomes is required, possibly including RCTs to optimize outcomes for surgical treatment of MTLE.