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Seizure Types and Frequency in Patients Who Fail Temporal Lobectomy for Intractable Epilepsy

Englot, Dario J. MD, PhD*,‡; Lee, Anthony T. BS*,‡; Tsai, Catherine BS*,‡; Halabi, Cathra MD*,§; Barbaro, Nicholas M. MD; Auguste, Kurtis I. MD*,‡,||; Garcia, Paul A. MD*,§; Chang, Edward F. MD*,‡

doi: 10.1227/NEU.0000000000000120
Research-Human-Clinical Studies

BACKGROUND: Temporal lobectomy can lead to favorable seizure outcomes in medically-refractory temporal lobe epilepsy (TLE). Although most studies focus on seizure freedom after temporal lobectomy, less is known about seizure semiology in patients who “fail” surgery. Morbidity differs between seizure types that impair or spare consciousness. Among TLE patients with seizures after surgery, how does temporal lobectomy influence seizure type and frequency?

OBJECTIVE: To characterize seizure types and frequencies before and after temporal lobectomy for TLE, including consciousness-sparing or consciousness-impairing seizures.

METHODS: We performed a retrospective longitudinal cohort study examining patients undergoing temporal lobectomy for epilepsy at our institution from January 1995 to August 2010.

RESULTS: Among 241 TLE patients who received temporal lobectomy, 174 (72.2%) patients achieved Engel class I outcome (free of disabling seizures), including 141 (58.5%) with complete seizure freedom. Overall seizure frequency in patients with persistent postoperative seizures decreased by 70% (P < .01), with larger reductions in consciousness-impairing seizures. While the number of patients experiencing consciousness-sparing simple partial seizures decreased by only 19% after surgery, the number of individuals having consciousness-impairing complex partial seizures and generalized tonic-clonic seizures diminished by 70% and 68%, respectively (P < .001). Simple partial seizure was the predominant seizure type in 19.1% vs 37.0% of patients preoperatively and postoperatively, respectively (P < .001). Favorable seizure outcome was predicted by a lack of generalized seizures preoperatively (odds ratio 1.74, 95% confidence interval 1.06-2.86, P < .5).

CONCLUSION: Given important clinical and mechanistic differences between seizures with or without impairment of consciousness, seizure type and frequency remain important considerations in epilepsy surgery.

ABBREVIATIONS: AED, antiepileptic drug

CPS, complex partial seizure

ECoG, electrocorticography

EEG, electroencephalography

GTCS, generalized tonic-clonic seizure

SPS, simple partial seizure

TLE, temporal lobe epilepsy

UCSF, University of California, San Francisco

*UCSF Epilepsy Center, University of California, San Francisco, California;

Department of Neurological Surgery, University of California, San Francisco, California;

§Department of Neurology, University of California, San Francisco, California;

Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana;

||Children's Hospital and Research Center Oakland, Oakland, California

Correspondence: Dario J. Englot, MD, PhD, Department of Neurological Surgery, University of California, San Francisco, 505 Parnassus Ave, Box 0112, San Francisco, CA 94143-0112. E-mail:

Received April 12, 2013

Accepted July 18, 2013

Copyright © by the Congress of Neurological Surgeons