Around 20-30% epileptic patients do not achieve seizure freedom despite well selected and tolerated pharmacological treatment. Surgery is a widely accepted treatment option for these patients. Factors influencing long term outcomes after elective surgical intervention remain poorly studied. One recent study (Lamberink et al., 2020) addressed this issue analysing the association between histopathology and seizure outcome and drug freedom up to 5 years after epilepsy surgery. In this retrospective, multicentre, longitudinal, cohort study, patients who had epilepsy surgery between Jan 1, 2000, and Dec 31, 2012, at 37 collaborating tertiary referral centres across 18 European countries of the European Epilepsy Brain Bank consortium were assessed.
Histopathological diagnoses and a minimal dataset of clinical variables were collected from existing local databases and patient records. The primary outcomes were freedom from disabling seizures (Engel class 1) and drug freedom at 1, 2, and 5 years after surgery. Proportions of individuals who were Engel class 1 and drug-free were reported for the 11 main categories of histopathological diagnosis.
It was found that the diagnoses of low-grade epilepsy associated neuroepithelial tumour (LEAT) (77,5%), vascular malformation (74%), and hippocampal sclerosis (71,5%) were associated with the best seizure outcome at 2 years after surgery. In contrast patients with focal cortical dysplasia type I or mild malformation of cortical development (50,0%), those with malformation of cortical development-other (52·3%), and those with no histopathological lesion (53·5%) had lowest rates of seizure freedom at 2 years. Let’s keep in mind that it is still better than best medical treatment. The proportion of patients being both Engel class 1 and drug-free was 0-14% at 1 year and increased to 14-51% at 5 years. Children were more often drug-free; temporal lobe surgeries had the best seizure outcomes. Interestingly, longer duration of epilepsy was associated with reduced chance of favourable seizure outcomes and drug freedom.
In conclusion, every drug-refractory patient with focal epilepsy should be a candidate for detailed pre-surgical evaluation. To achieve best results of epilepsy surgery, pre-surgical evaluation should be done as early as possible in the course of disease.
Key Points:
Surgery, refractory epilepsy, predicative factors, outcome
References:
Lamberink HJ, Otte WM, Blümcke I, Braun KPJ; European Epilepsy Brain Bank writing group; study group; European Reference Network EpiCARE. Seizure outcome and use of antiepileptic drugs after epilepsy surgery according to histopathological diagnosis: a retrospective multicentre cohort study. Lancet Neurol. 2020 Sep;19(9):748-757. doi: 10.1016/S1474-4422(20)30220-9.