Postoperative prognostic analysis of patients with MR imaging-negative temporal lobe epilepsy

Abstract

Objective To determine whether unilateral-only interictal discharges on pre-surgical scalp EEG or multimodal pre-surgical evaluation are associated with surgical outcomes in patients with MR imaging-negative temporal lobe epilepsy (TLE) who underwent standard anterior temporal lobectomy (ATL). Methods One hundred and seventeen patients with TLE who underwent standard ATL from January 2000 to December 2013 were enrolled. According to the seizures at interictal period, these patients were divided into unilateral-only interictal discharge group (n=54) and bilateral interictal discharge group (n=63). According to the preoperative assessment, these patients were divided into multimodal evaluation group (n=72, two and above evaluation strategies besides electroencephalogram) and single modal evaluation group (n=45, electroencephalogram+one evaluation strategy). Follow-up for 12 months was performed; postsurgical outcomes included excellent outcome, defined as Engel class I, and non-excellent outcome, defined as Engel II-IV. Kaplan-Meier survival analysis and Cox proportion hazards were performed to compare the prognoses of patients from different groups. Results Totally, 73 patients (62.4%) achieved excellent outcome following ATL. In 54 with unilateral-only interictal discharges, 41 had excellent outcome; and in 63 with bilateral interictal discharge group, 32 patients had excellent outcome; significant difference in percentage of excellent outcome was noted between the two groups (P 0.05). Conclusion Multimodal pre-surgical evaluation is associated with better outcomes following standard ATL in the patients with MR imaging-negative TLE; however, for patients with unilateral-only interictal discharges, multimodal pre-surgical evaluation method may be not essential as compared with single modal pre-surgical evaluation method. Key words: Temporal lobe epilepsy; Prognois; Pre-surgical evaluation