Table of Contents
Epilepsy Research and Treatment
Volume 2012 (2012), Article ID 201651, 10 pages
http://dx.doi.org/10.1155/2012/201651
Review Article

Temporal Lobe Epilepsy Surgery Failures: A Review

1Division of Neurology, Hôpital Notre-Dame du CHUM, University of Montreal, Montreal, QC, Canada H2L 4M1
2Division of Neurosurgery, Hôpital Notre-Dame du CHUM, University of Montreal, Montreal, QC, Canada H2L 4M1

Received 26 November 2011; Revised 17 January 2012; Accepted 1 February 2012

Academic Editor: Giangennaro Coppola

Copyright © 2012 Adil Harroud et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Patients with temporal lobe epilepsy (TLE) are refractory to antiepileptic drugs in about 30% of cases. Surgical treatment has been shown to be beneficial for the selected patients but fails to provide a seizure-free outcome in 20–30% of TLE patients. Several reasons have been identified to explain these surgical failures. This paper will address the five most common causes of TLE surgery failure (a) insufficient resection of epileptogenic mesial temporal structures, (b) relapse on the contralateral mesial temporal lobe, (c) lateral temporal neocortical epilepsy, (d) coexistence of mesial temporal sclerosis and a neocortical lesion (dual pathology); and (e) extratemporal lobe epilepsy mimicking TLE or temporal plus epilepsy. Persistence of epileptogenic mesial structures in the posterior temporal region and failure to distinguish mesial and lateral temporal epilepsy are possible causes of seizure persistence after TLE surgery. In cases of dual pathology, failure to identify a subtle mesial temporal sclerosis or regions of cortical microdysgenesis is a likely explanation for some surgical failures. Extratemporal epilepsy syndromes masquerading as or coexistent with TLE result in incomplete resection of the epileptogenic zone and seizure relapse after surgery. In particular, the insula may be an important cause of surgical failure in patients with TLE.