The hidden causes of epilepsy surgery failure: a systematic review

Resective surgery for focal epilepsy carries a much greater chance for curing seizures, especially if there is an associated lesion on neuroimaging. In general, surgical failure should be defined as identification of seizure(s) following the operation, with persistence of habitual seizures perhaps the most important criteria for clinical diagnosis of surgical failure. Prediction of surgical failure should be individualized to the clinical scenario. The running down phenomenon should be kept in mind. The two main reasons for failure to localize the epileptogenic zone (EZ) are the diffuse nature of specific types of intractable epilepsy syndromes and the anatomical limitations of electrode implantation (insular cortex, interhemispheric surfaces, posterior basal orbitofrontal region).The first may be considered a failure in the preoperative evaluation and most often occurs due to the clinician s inability to accurately localize the epileptogenic zone. The second is surgical technique related and potentially avoidable.The possibility of combined depth electrode and subdural electrode implantation may be a better method in approaching these difficult anatomical areas. Alternatively, stereoelectroencephalography may be a better method for accessing difficult to access or more widespread cortical regions.

Keywords:

epilepsy surgery failure , Temporal lobe epilepsy , Temporal plus epilepsy , SEEG