The Changing Face of Epileptology? Results of the Initial Q-PULSE Survey

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

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.

The evolution of epilepsy surgery between 1991 and 2011 in nine major epilepsy centers across the United States, Germany, and Australia

OBJECTIVE

Epilepsy surgery is the most effective treatment for select patients with drug-resistant epilepsy. In this article, we aim to provide an accurate understanding of the current epidemiologic characteristics of this intervention, as this knowledge is critical for guiding educational, academic, and resource priorities.

METHODS

We profile the practice of epilepsy surgery between 1991 and 2011 in nine major epilepsy surgery centers in the United States, Germany, and Australia. Clinical, imaging, surgical, and histopathologic data were derived from the surgical databases at various centers.

RESULTS

Although five of the centers performed their highest number of surgeries for mesial temporal sclerosis (MTS) in 1991, and three had their highest number of MTS surgeries in 2001, only one center achieved its peak number of MTS surgeries in 2011. The most productive year for MTS surgeries varied then by center; overall, the nine centers surveyed performed 48% (95% confidence interval [CI] -27.3% to -67.4%) fewer such surgeries in 2011 compared to either 1991 or 2001, whichever was higher. There was a parallel increase in the performance of surgery for nonlesional epilepsy. Further analysis of 5/9 centers showed a yearly increase of 0.6 ± 0.07% in the performance of invasive electroencephalography (EEG) without subsequent resections. Overall, although MTS was the main surgical substrate in 1991 and 2001 (proportion of total surgeries in study centers ranging from 33.3% to 70.2%); it occupied only 33.6% of all resections in 2011 in the context of an overall stable total surgical volume.

SIGNIFICANCE

These findings highlight the major aspects of the evolution of epilepsy surgery across the past two decades in a sample of well-established epilepsy surgery centers, and the critical current challenges of this treatment option in addressing complex epilepsy cases requiring detailed evaluations. Possible causes and implications of these findings are discussed.

Epilepsy surgery in the United States: Analysis of data from the National Association of Epilepsy Centers

OBJECTIVE

To examine trends in epilepsy-related surgical procedures performed at major epilepsy centers in the US between 2003 and 2012, and in the service provision infrastructure of epilepsy centers over the same time period.

METHODS

We analyzed data from the National Association of Epilepsy Centers' (NAEC) annual surveys. The total annual figures, annual average figures per center and annual rates of each surgical procedure based on US population numbers for that year were calculated. Additional information on center infrastructure and manpower was also examined.

RESULTS

The number of the NAEC's level 3 and level 4 epilepsy centers submitting annual survey reports increased from 37 centers in 2003 to 189 centers in 2012. The average reported number of Epilepsy Monitoring Unit (EMU) beds per center increased from 7 beds in 2008 to 8 beds in 2012. Overall annual EMU admission rates doubled between 2008 and 2012 but the average number of EMU admissions and epilepsy surgeries performed per center declined over the same period. The annual rate of anterior temporal lobectomies (ATL) for mesial temporal sclerosis (MTS) declined by >65% between 2006 and 2010. The annual rate of extratemporal surgery exceeded that of ATL for MTS from 2008 onwards, doubled between 2007 and 2012 and comprised 38% of all resective surgeries in 2012. Vagus nerve stimulator implant rates consistently increased year on year and exceeded resective surgeries in 2011 and 2012.

CONCLUSION

The last decade has seen a major change in the US epilepsy surgery landscape. Temporal lobectomies, particularly for MTS, have declined despite an increase in EMU admissions. On the other hands, case complexity correspondingly increased as evidenced by more extratemporal surgery, intracranial recordings and palliative procedures.