Which Factors Predict Successful Epilepsy Reoperations?

LOS ANGELES—Among patients with intractable focal epilepsy who have failed one or more epilepsy surgeries, reoperation may provide long-term seizure control, according to research presented at the 70th Annual Meeting of the American Academy of Neurology. Patients with prior epilepsy surgery are less likely to achieve seizure freedom, however, compared with patients undergoing initial epilepsy surgery, the researchers said.

“It is possible to achieve long-term seizure control in patients with failed prior epilepsy surgery,” said Ruta Yardi, MD, a researcher at the Cleveland Clinic, and colleagues. “A lesional MRI, specific prior postoperative pathology, and fewer prior resections seem to predict better outcomes.” These results may be helpful in identifying candidates for reoperation, the investigators said.

Epilepsy surgery is the most effective treatment option for patients with medically refractory focal epilepsy, but initial surgeries may not be successful, Dr. Yardi and colleagues said. A small percentage of patients who do not benefit from a first surgery may be evaluated for another resection. Data for how outcomes vary with successive surgeries are limited, however, the researchers said.

To assess longitudinal seizure outcomes following reoperations in patients with intractable focal epilepsy and identify prognostic factors that influence these outcomes, Dr. Yardi and colleagues retrospectively studied 898 patients (448 female; about a third pediatric) who underwent epilepsy surgery at the Cleveland Clinic between 1995 and 2016. The investigators analyzed baseline characteristics, known predictors of seizure outcome, surgical data, pathology, and postoperative seizure recurrence. The primary outcome was complete seizure freedom (ie, Engel Class IA) at last follow-up.

The researchers analyzed the data using Kaplan–Meier survival curves and univariate and multivariate hazard modeling. The analysis included 788 patients without prior surgery, 92 patients with one prior surgery, and 18 patients with two or more prior surgeries. Two years after the most recent epilepsy surgery, 58% of patients with no prior surgery were seizure-free, compared with 49% of patients who had one prior surgery and 39% of patients who had two or more prior surgeries. Patients with more than one surgery were more likely to have an Engel outcome score of greater than Class I.

Variables that correlated with better seizure outcome in the univariate analysis included female gender; a lesional initial MRI; no history of generalization; and mesial temporal sclerosis, malformations of cortical development, or tumor on pathology. In the multivariate model, gender, history of generalization, and number of prior surgeries remained statistically significant.

—Jake Remaly