You could be reading the full-text of this article now if you...

If you have access to this article through your institution,
you can view this article in

Surgical Outcomes in Patients With Extratemporal Epilepsy and Subtle or Normal Magnetic Resonance Imaging Findings

See, Siew-Ju MBBS*; Jehi, Lara E. MD; Vadera, Sumeet MD; Bulacio, Juan MD; Najm, Imad MD; Bingaman, William MD

Neurosurgery:
doi: 10.1227/01.neu.0000429839.76460.b7
Research-Human-Clinical Studies
Abstract

BACKGROUND: Surgery is an important therapeutic option in patients with medically refractory epilepsy. The combination of an extratemporal epileptic focus and nonlesional magnetic resonance imaging (MRI) was often believed to portend a poor outcome.

OBJECTIVE: To investigate the outcome and analyze potential prognostic predictors in patients without lesions on MRI who underwent extratemporal resections.

METHODS: Clinical, presurgical evaluation, invasive monitoring, and postoperative data of patients with high-resolution MRI that was initially reported as nonlesional were reviewed. Patients were reclassified as MRI-positive if an MRI abnormality related to the epilepsy was revealed at the multidisciplinary presurgical patient management conference, or as MRI-negative if imaging remained normal or revealed incidental findings.

RESULTS: Sixty patients were identified; 72% were MRI-negative. In the original cohort, the median seizure-free duration was 1.32 years (95% confidence interval [CI], 0.16-2.0); probability of seizure freedom at 2 years was 36% (95% CI, 30%–43%). In the MRI-negative group, the median seizure-free duration was 1.52 years (95% CI, 0.12-5.17); probability of seizure freedom at 2 years was 42% (95% CI, 33%–50%). Complete resection of ictal onset areas and absence of acute postoperative seizures were significantly associated with longer seizure freedom (risk ratio 4.9, P = .004; 95% CI, 1.6-16.7 and 22.1, P < .001; 95% CI, 5.9-94.7, respectively).

CONCLUSION: Among patients with medically refractory MRI nonlesional extratemporal epilepsy, detailed evaluation and subsequent resection leads to seizure freedom in 42% of patients at 2 years.

ABBREVIATIONS: APOS, acute postoperative seizure

CI, confidence interval

EEG, electroencephalography

FCD, focal cortical dysplasia

PET, positron emission tomography

PMC, patient management conference

VNS, vagal nerve stimulator

Author Information

*Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Singapore;

Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio

Correspondence: Lara E. Jehi, MD, Epilepsy Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195. E-mail: jehil@ccf.org

Received September 20, 2011

Accepted March 19, 2013

Copyright © by the Congress of Neurological Surgeons