Posterior quadrant epilepsy surgery: case series of a South American hospital

Background: Posterior quadrant epilepsy (PCE) is a type of focal epilepsy that originates in the parietal lobe, occipital lobe, and the parietal-occipital border of the temporal lobe, or in any combination of these regions. PCE has a low incidence, but it can cause a great burden in disability-adjusted life years. In this retrospective cohort, patients of all ages with a diagnosis of PCE between 2006 and 2019 were evaluated in a referral center in Bogotá, Colombia. A descriptive analysis of demographic data, clinical history, imaging findings, type of surgery, histopathological diagnosis, outcome, and follow-up was performed using the Engel scale. Methods: This study included refractory PCE patients of all ages who were evaluated by the epilepsy surgery group of the Hospital Universitario San Ignacio from 2006 to 2019. Clinical, imaging and surgical variables were obtained from the medical records and analyzed. Results: Thirteen patients were included in the study, including 8 males and 5 females. The mean age of diagnosis was 8.8 years, while the mean age of surgery was 25 years. The most frequent clinical finding was intellectual disability. The most common findings on magnetic resonance imaging were encephalomalacia and gliosis. In 61.5% of the patients, the lateralization of video-EEG matched with brain magnetic resonance imaging alteration. The most frequent types of surgery performed were lobectomies, lesionectomies and cortical resections. Seizure-freedom was achieved in approximately one third of the patients; however, more than half of the patients were free of disabling seizures or had significant improvement after surgery. Conclusions: PCE surgery is scarcely performed worldwide, therefore the effectiveness and outcomes are quite variable in the reported literature. In this study, we show that patients with PCE can obtain great benefits in terms of reduction of seizures with a low risk of surgical complications, encouraging the use of this type of procedure in carefully selected patients.