Surgical Treatment of Extratemporal Epilepsy: Results and Prognostic Factors

BACKGROUND: Surgery is a widely accepted option for the treatment of pharmacoresistant epilepsies of extratemporal origin. OBJECTIVE: To analyze clinical and epileptological results and to provide prognostic factors influencing seizure outcome. METHODS: This retrospective single-center study comprises a consecutive series of 383 patients, most of whom had an identifiable lesion on MRI, who underwent resective surgery for extratemporal epilepsy. Data including diagnostic modalities, surgical treatment, histopathology, prognostic factors, and epileptological outcome were analyzed. RESULTS: Resective procedures were located as follows: frontal (n = 183), parietal (n = 44), occipital (n = 24), and insular (n = 24). In 108 cases resection included more than 1 lobe. Histopatholological evaluation revealed focal cortical dysplasias (n = 178), tumors (n = 110), cavernomas (n = 27), gliosis (n = 42), and nonspecific findings (n = 36). A distinct epileptogenic lesion was detected in 338 (88.7%) patients. After a mean follow-up of 54 mo, 227 (62.5%) patients remained free from disabling seizures (Engel class I), and 178 (49%) were completely seizure free (Engel class Ia). There was no perioperative mortality. Permanent morbidity was encountered in 46 cases (11.8%). The following predictors were significantly associated with excellent seizure outcome (Engel I): lesion visible on magnetic resonance imaging (MRI; P = .02), noneloquent location (P = .01), complete resection of the lesion (P = .001), absence of epileptic activity postoperatively (P = .001), circumscribed histological findings (P = .001), lower age at surgery (P = .008), and shorter duration of epilepsy (P = .02). CONCLUSION: Surgical treatment of extratemporal epilepsy provides satisfying epileptological results with an acceptable morbidity. Best results can be achieved in younger patients with circumscribed MRI lesions, which can be resected completely.