Predictors of surgical candidacy in 414 epilepsy patients admitted to the EMU

OBJECTIVES: Admission to an Epilepsy Monitoring Unit (EMU) is essential for pre-surgical evaluation of patients with medically-refractory epilepsy; however, prolonged referral times and resource limitations are significant access barriers. Therefore, identification of pre-EMU variables that predict potential surgical candidates can assist in the triage of patient admissions to the EMU.

METHODS: In this hypothesis-generating study, a retrospective analysis of patients admitted for pre-surgical evaluation to the Toronto Western Hospital EMU (2004-2011) was performed. Univariate and multivariate logistic regression was used to identify variables that could independently predict subsequent surgical candidacy following EMU evaluation.

RESULTS: Four hundred and fourteen patients were admitted to the EMU. Overall, 259 patients (62.5%) were identified as potential surgical candidates. One hundred and seven patients (25.8%) required invasive electroencephalogram (iEEG) implantations; of 75 patients consenting to iEEG analysis 39 underwent a subsequent resective procedure. Male patients and those with a lesion on MRI were 1.9 times more likely to be surgical candidates (95% CI 1.18-2.98 and 0.94-3.80, respectively), while patients with non-localizable seizures were seven times less likely (95% CI 0.02-1.25).

CONCLUSION: In this retrospective, hypothesis-generating study male gender, presence of a lesion on MRI and localizable seizures on routine outpatient EEG analysis independently predicted subsequent resective epilepsy surgical candidacy in EMU patients. Upon validation by other studies, these variables may be considered by clinicians referring patients to the EMU in order to improve wait times and optimize patient care.