Introduction: Occipital lobe epilepsy (OLE) is a relatively rare focal epilepsy syndrome. While seizures are refractory to medical management in many OLE patients, surgical resection has proven a viable treatment option for these individuals. Previous studies have examined seizure freedom rates following surgical resection for OLE; however, these case series are limited by small sample sizes and patient heterogeneity and thus exhibit significant variability in their results. As such, post-operative seizure freedom rates and their predictors for OLE patients remain poorly understood.
Methods: We performed a systematic PubMed for manuscripts published between January 1990 and June 2015. Seizure freedom rates following OLE surgery were examined and potential predictors were evaluated with separate meta-analyses. Post-operative visual deficits were also examined.
Results: We identified 27 case series comprised of 584 patients with greater than 1 year of follow-up. Post-operative seizure freedom (Engel Class I outcome) was observed in 65% of patients, and this outcome was significantly predicted by age less than 18 years (OR 1.54, 95% CI 1.13-2.18), focal lesion on pathologic analysis (OR 2.08, 95% CI 1.58-2.89), and abnormal pre-operative MRI (OR 3.24, 95% 2.03-6.55). Of these patients, 175 also had reported visual outcomes, and 57% of these individuals demonstrated some degree of hemispheric visual decline following surgery. For these patients, we did not find any relationship between post-operative visual outcomes and other factors including post-operative seizure freedom.
Conclusions: For many OLE patients with medically refractory seizures, surgical resection is a viable and effective option with nearly two-thirds of patients achieving seizure freedom. Patients must be counselled regarding the risk of visual decline following surgery. Further study is warranted to elucidate factors associated with post-operative visual outcomes.
Patient Care: Our systematic review and meta-analysis identifies several patient factors that are prognostic for seizure freedom following occipital lobe epilepsy. Such information will be helpful in identifying appropriate occipital lobe epilepsy patients for surgical management.
Learning Objectives: By the conclusion of this session, participants should be to: 1) Understand the efficacy of surgical resection for occipital lobe epilepsy, 2) Identify patient factors predictive for seizure freedom following surgery, and 3) Recognize the need for further study to identify factors prognostic for visual outcomes following occipital lobe epilepsy surgery.