The impact of temporal lobe surgery on cure and mortality of drug-resistant epilepsy: summary of a workshop

Abstract

The Third International Spring Epilepsy Research Conference took place in Georgetown, Cayman Islands from April 26 to May 3, 2003. One workshop discussed the impact of epilepsy surgery on seizure outcome and mortality of antiepileptic drug (AED)-resistant temporal lobe epilepsy. This article summarizes the information presented at this workshop. Although two-thirds of adult patients undergoing epilepsy surgery become seizure-free with continued AED treatment, current clinical experience shows that seizure recurrence occurs in one-third of patients when AEDs are withdrawn under medical supervision. Additional seizure recurrence occurring after AED taper, poor drug compliance and even while patients continue on AEDs after surgery leave only approximately one-third of patients cured after temporal lobe resection. Mostly because so many patients prefer to stay on AEDs although they are free of disabling seizures after surgery, a randomised controlled trial of AED discontinuation is needed to determine if in fact only one-third of patients are cured after surgery. Based on the functional anatomy of temporal lobe surgery two hypotheses are presented why only a minority of patients are cured after surgery. The type and the prognostic significance of seizures after surgery is discussed. Recent studies have suggested that successful temporal lobe surgery may be able to normalize the increased standard mortality ratio (SMR) of drug-resistant temporal lobe epilepsy. However, pre-existing differences in SMR between those cured and those not cured by temporal lobe surgery and other unresolved methodological issues make it difficult at present to fully evaluate the impact of surgery on mortality. Future studies are thus warranted to specifically address the impact of temporal lobe surgery on cure and mortality.