The Changing Nature of Epilepsy Surgery: A Retrospective Review of Practice Profiles

Abstract

Objectives: Recent literature documents a trend of gradual decline in temporal lobe (resective) epilepsy surgery over the past decade. Amongst these, a large scale, comprehensive survey done in selected European, Australian and American centres documents trends of resective temporal epilepsy surgery across two decades. Montreal Neurological Institute has been the leading epilepsy surgery centre for more than 50 years now. It has been at the forefront of investigating and managing epilepsy in Canada. We have looked into the trends of epilepsy surgery in our institute in the past 44 years. Methods: The records of all adult epilepsy surgery procedures (excluding reoperations) performed by the senior authors were analysed from 1971 to 2015. Data retrieved for analysis included type of surgery (intracranial recording, resective, and neuromodulatory) and the specific surgical target for resection. Procedures were grouped into temporal resective, extratemporal (ET) resective and placement of intracranial electrodes (stereotactic electroencephalogram (SEEG)). Results: A total of 2,078 new procedures were performed from 1971 to 2015 at the Montreal Neurological Institute. Temporal procedures constituted the bulk of the proportion of all procedures each year and the entire study period. SEEG group shows linear increase in the number of cases over the years catching up with the total number of temporal procedures. Conclusions: Our study involving a homogenous dataset spanning nearly 50 years shows a decline in temporal lobe surgeries and an increase in intracranial investigations despite the class I evidence of its effectiveness. This corroborates the trends in epilepsy surgery practice profiles in tertiary centres of developed countries.

Guidelines for Specialized Epilepsy Centers

“…The importance of specialized training for epilepsy neurosurgeons is increasingly recognized. 29 , 30 Evidence indicates that adding a sub–specialty-trained functional neurosurgeon dedicated to epilepsy surgery improved the volume and outcomes of patients referred to surgery. 31 In North America, board certification is an indicator of training and experience.…”

“…As Wada testing is more invasive and carries more risk than functional imaging, it should be used selectively when the benefit of assessing memory outweigh the risks of testing. 11 , 29 …”

Outlines to Initiate Epilepsy Surgery in Low- and Middle-Income Countries

“…A surgeon is also essential if invasive diagnostics like intracranial EEG are required to clarify the seizure onset zone [6,58], but the surgical requirements in terms of equipment and competency must be met for any chosen procedure [15,23]. Stereotactic EEG recording through intracranial electrodes is an increasingly common procedure in HIC [67], but this invasive technique requires robotic or stereotactic system assistance and an appropriate epilepsy monitoring unit. Consequently, it is quite demanding in terms of equipment, expertise, and diagnostic resources, which might be a major barrier to adoption in resource-limited settings.…”