title: Temporal plus epilepsy is a major determinant of temporal lobe surgery failures.
abstract: Reasons for failed temporal lobe epilepsy surgery remain unclear. Temporal plus epilepsy, characterized by a primary temporal lobe epileptogenic zone extending to neighboured regions, might account for a yet unknown proportion of these failures. In this study all patients from two epilepsy surgery programmes who fulfilled the following criteria were included: (i) operated from an anterior temporal lobectomy or disconnection between January 1990 and December 2001; (ii) magnetic resonance imaging normal or showing signs of hippocampal sclerosis; and (iii) postoperative follow-up ≥ 24 months for seizure-free patients. Patients were classified as suffering from unilateral temporal lobe epilepsy, bitemporal epilepsy or temporal plus epilepsy based on available presurgical data. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom over time. Predictors of seizure recurrence were investigated using Cox proportional hazards model. Of 168 patients included, 108 (63.7%) underwent stereoelectroencephalography, 131 (78%) had hippocampal sclerosis, 149 suffered from unilateral temporal lobe epilepsy (88.7%), one from bitemporal epilepsy (0.6%) and 18 (10.7%) from temporal plus epilepsy. The probability of Engel class I outcome at 10 years of follow-up was 67.3% (95% CI: 63.4-71.2) for the entire cohort, 74.5% (95% CI: 70.6-78.4) for unilateral temporal lobe epilepsy, and 14.8% (95% CI: 5.9-23.7) for temporal plus epilepsy. Multivariate analyses demonstrated four predictors of seizure relapse: temporal plus epilepsy (P < 0.001), postoperative hippocampal remnant (P = 0.001), past history of traumatic or infectious brain insult (P = 0.022), and secondary generalized tonic-clonic seizures (P = 0.023). Risk of temporal lobe surgery failure was 5.06 (95% CI: 2.36-10.382) greater in patients with temporal plus epilepsy than in those with unilateral temporal lobe epilepsy. Temporal plus epilepsy represents a hitherto unrecognized prominent cause of temporal lobe surgery failures. In patients with temporal plus epilepsy, anterior temporal lobectomy appears very unlikely to control seizures and should not be advised. Whether larger resection of temporal plus epileptogenic zones offers greater chance of seizure freedom remains to be investigated.
authors.affiliation: 1 Paediatric Neurology Unit, Children's Hospital A. Meyer-University of Florence, 50139, Florence, Italy carmen.barba@meyer.it.
authors.forename: Carmen
authors.initials: C
authors.lastname: Barba
authors.affiliation: 2 Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, 69500, Lyon and Lyon 1 University, France 3 Lyon's Research Neuroscience Centre, INSERM U1028/CNRS UMR5292, Lyon, France 4 Epilepsy Institute (IDEE), Lyon, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Rheims
authors.affiliation: 5 Epilepsy Unit, Neurology Department, 38043, Michallon Hospital, Grenoble, France.
authors.forename: Lorella
authors.initials: L
authors.lastname: Minotti
authors.affiliation: 6 Department of Functional Neurosurgery, Hospices Civils de Lyon, 69003 Lyon, and Lyon 1 University, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Guénot
authors.affiliation: 7 Neurosurgery Department, Michallon Hospital, 38043, Grenoble, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Hoffmann
authors.affiliation: 7 Neurosurgery Department, Michallon Hospital, 38043, Grenoble, France.
authors.forename: Stephan
authors.initials: S
authors.lastname: Chabardès
authors.affiliation: 2 Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, 69500, Lyon and Lyon 1 University, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Isnard
authors.affiliation: 5 Epilepsy Unit, Neurology Department, 38043, Michallon Hospital, Grenoble, France 8 GIN, Inserm U836, University Grenoble-Alpes, Grenoble, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Kahane
authors.affiliation: 3 Lyon's Research Neuroscience Centre, INSERM U1028/CNRS UMR5292, Lyon, France 4 Epilepsy Institute (IDEE), Lyon, France 9 Department of Clinical Neurosciences, Centre Hospitalo-Universitaire Vaudois, 1011, Lausanne, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ryvlin
mesh_terms: D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000639:trends*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013702:Temporal Lobe / Q000473:pathology / Q000601:surgery*; D017211:Treatment Failure; D016896:Treatment Outcome; D055815:Young Adult
keywords: epilepsy surgery; predictor of surgical outcome; temporal lobe epilepsy; temporal plus