European Journal of Neurology 2014, 21: 814–815
doi:10.1111/ene.12358
EDITORIAL
Temporal trends in epilepsy surgery See paper by Helmstaedter et al. on page 827. The decade 2001–2010 can, with some justification, be termed the decade of epilepsy surgery, or at least the decade when the importance of epilepsy surgery for the treatment of refractory localization-related epilepsy was increasingly recognized. The year 2001 saw the publication of the first randomized controlled trial data demonstrating the superiority of epilepsy surgery over continued medical therapy in people with treatment resistant mesial temporal lobe epilepsy (mTLE) [1]. In this study 40 people were randomized to either epilepsy surgery or continued medical treatment. At 1 year 58% of the surgical candidates were free from seizures impairing awareness compared with only 8% in the medical group. Similarly people in the surgical group reported fewer seizures impairing awareness and significantly better quality of life than the medical group [1]. Since then multiple expert commentaries, in addition to a practice protocol from the American Academy of Neurology [2], have been published advocating early referral for evaluation for surgery in people with refractory temporal lobe epilepsy [typically after two anti-epileptic drug (AED) failures]. It is therefore of interest to observe patterns of epilepsy surgery performed over the intervening period. The paper by Dr Helmstaedter and colleagues published in this issue affords such an opportunity [3]. In this study the authors retrospectively reviewed the case notes of all patients who had epilepsy surgery at three large epilepsy centres in Germany between 1988 (when epilepsy surgery started in Germany) and 2008. In total 2812 patients underwent epilepsy surgery for refractory localization-related epilepsy with hippocampal sclerosis being the predominant underlying pathology in 1461 (52%). The number of epilepsy surgical procedures performed increased in each 4-year period from 1988 (approximately 300) to 2004 (approximately 750) with a corresponding increase in the proportion with hippocampal sclerosis (increasing from 30% in 1988–1992 to 58% in 2001– 2004). The numbers subsequently decreased in the last period 2005–2008 (approximately 600) although the proportion of those with hippocampal sclerosis remained stable (55%). People with hippocampal sclerosis had a significantly longer duration of epilepsy than those with other pathologies. Interestingly the epilepsy duration of people with hippocampal sclerosis did not decrease over the period of observation but rather appeared to
814
increase. This is contrary to expectations, whereby the epilepsy duration of people with classical hippocampal sclerosis at the time of surgical evaluation should have decreased as people are referred earlier as awareness of the efficacy of epilepsy surgery increased. The failure to observe a sustained increase in the number of hippocampal temporal lobe resections being performed is perplexing but mirrors findings from several other countries. In the USA a multicentre randomized control trial involving 18 different epilepsy centres to determine whether early temporal lobe surgery resulted in improved seizure control and better quality of life over continued medical therapy was terminated prematurely due to difficulty recruiting patients. (Patients were eligible for the trial if they had mTLE with ongoing disabling seizures for no more than two consecutive years despite two adequate trials of brand-name AEDs.) The planned enrolment for the study was 200 participants but it was terminated with only 38 patients enrolled (23 in the continued AED group, 15 in the surgical group) [4]. The difficulties encountered by this study in accruing suitable candidates may in part be due to the fact that mTLE may not be as common as previously estimated although the short duration of epilepsy mandated by the study entry criteria was likely to have been the major contributory factor. In a study examining epilepsy hospital admissions in the USA between 1990 and 2008, it was estimated that there were 112 026 hospital admissions for refractory focal epilepsy and 6653 resective surgeries. A trend of increasing epilepsy-related admissions (from approximately 4000 to 8000 per year) was not accompanied by an increase in epilepsy surgery (approximately 300–450 per year), where in fact there was a trend of a decreasing proportion of surgical admissions undergoing surgery. This was accompanied by an overall trend of decreasing admissions to highvolume epilepsy centres with a corresponding increase in admissions to lower-volume epilepsy centres where epilepsy surgery is less likely to be performed [5]. Referrals to other epilepsy centres may partly explain the fall in surgery numbers in the last 4-year period of observation in the German study [3]. In Sweden the annual numbers for epilepsy surgery performed declined at a rate of 2.5 per year between 1991 and 2007, from an initial figure of 78 to
doi:10.1111/ene.12358
EDITORIAL
Temporal trends in epilepsy surgery See paper by Helmstaedter et al. on page 827. The decade 2001–2010 can, with some justification, be termed the decade of epilepsy surgery, or at least the decade when the importance of epilepsy surgery for the treatment of refractory localization-related epilepsy was increasingly recognized. The year 2001 saw the publication of the first randomized controlled trial data demonstrating the superiority of epilepsy surgery over continued medical therapy in people with treatment resistant mesial temporal lobe epilepsy (mTLE) [1]. In this study 40 people were randomized to either epilepsy surgery or continued medical treatment. At 1 year 58% of the surgical candidates were free from seizures impairing awareness compared with only 8% in the medical group. Similarly people in the surgical group reported fewer seizures impairing awareness and significantly better quality of life than the medical group [1]. Since then multiple expert commentaries, in addition to a practice protocol from the American Academy of Neurology [2], have been published advocating early referral for evaluation for surgery in people with refractory temporal lobe epilepsy [typically after two anti-epileptic drug (AED) failures]. It is therefore of interest to observe patterns of epilepsy surgery performed over the intervening period. The paper by Dr Helmstaedter and colleagues published in this issue affords such an opportunity [3]. In this study the authors retrospectively reviewed the case notes of all patients who had epilepsy surgery at three large epilepsy centres in Germany between 1988 (when epilepsy surgery started in Germany) and 2008. In total 2812 patients underwent epilepsy surgery for refractory localization-related epilepsy with hippocampal sclerosis being the predominant underlying pathology in 1461 (52%). The number of epilepsy surgical procedures performed increased in each 4-year period from 1988 (approximately 300) to 2004 (approximately 750) with a corresponding increase in the proportion with hippocampal sclerosis (increasing from 30% in 1988–1992 to 58% in 2001– 2004). The numbers subsequently decreased in the last period 2005–2008 (approximately 600) although the proportion of those with hippocampal sclerosis remained stable (55%). People with hippocampal sclerosis had a significantly longer duration of epilepsy than those with other pathologies. Interestingly the epilepsy duration of people with hippocampal sclerosis did not decrease over the period of observation but rather appeared to
814
increase. This is contrary to expectations, whereby the epilepsy duration of people with classical hippocampal sclerosis at the time of surgical evaluation should have decreased as people are referred earlier as awareness of the efficacy of epilepsy surgery increased. The failure to observe a sustained increase in the number of hippocampal temporal lobe resections being performed is perplexing but mirrors findings from several other countries. In the USA a multicentre randomized control trial involving 18 different epilepsy centres to determine whether early temporal lobe surgery resulted in improved seizure control and better quality of life over continued medical therapy was terminated prematurely due to difficulty recruiting patients. (Patients were eligible for the trial if they had mTLE with ongoing disabling seizures for no more than two consecutive years despite two adequate trials of brand-name AEDs.) The planned enrolment for the study was 200 participants but it was terminated with only 38 patients enrolled (23 in the continued AED group, 15 in the surgical group) [4]. The difficulties encountered by this study in accruing suitable candidates may in part be due to the fact that mTLE may not be as common as previously estimated although the short duration of epilepsy mandated by the study entry criteria was likely to have been the major contributory factor. In a study examining epilepsy hospital admissions in the USA between 1990 and 2008, it was estimated that there were 112 026 hospital admissions for refractory focal epilepsy and 6653 resective surgeries. A trend of increasing epilepsy-related admissions (from approximately 4000 to 8000 per year) was not accompanied by an increase in epilepsy surgery (approximately 300–450 per year), where in fact there was a trend of a decreasing proportion of surgical admissions undergoing surgery. This was accompanied by an overall trend of decreasing admissions to highvolume epilepsy centres with a corresponding increase in admissions to lower-volume epilepsy centres where epilepsy surgery is less likely to be performed [5]. Referrals to other epilepsy centres may partly explain the fall in surgery numbers in the last 4-year period of observation in the German study [3]. In Sweden the annual numbers for epilepsy surgery performed declined at a rate of 2.5 per year between 1991 and 2007, from an initial figure of 78 to
