Title: What is the best age for surgery in drug-resistant mesial temporal lobe epilepsy?
Abstract: To the Editors: Studying risk factors for recurrence after antiepileptic drug (AED) withdrawal in patients treated with anterior temporal lobectomy (ATL) in mesial temporal lobe epilepsy (MTLE), Rathore et al. found, in univariate analysis, that surgery at age of 30 years or older and duration of epilepsy before surgery of 20 years or more were significant risk factors. They conclude “these results reemphasize the need to consider epilepsy surgery at earlier age” (Rathore et al., 2011). As a child neurologist, it called my attention for its practical implications. The authors did not mention an important selection bias: the older patients and the longer epilepsies were those more untreatable along the years. In multivariate analysis, Rathore et al. found that older age at surgery and longer epilepsy before surgery lost statistical significance, whereas absence of hippocampal sclerosis (HS) as a postsurgical pathologic finding remained a significant risk factor (Rathore et al., 2011). It is reasonable to suppose that surgery should be indicated as soon as possible in refractory MTLE considering its adverse effects in, for example, social life and employment (Engel, 2004). It has been suggested that epilepsy leads to cognitive impairment and behavioral abnormalities. However, confounders, as AEDs, do not allow one to assess if ictal activity itself along the years could have some deleterious cumulative effect on temporal or extratemporal cortex (Vingerhoets, 2006), thereby worsening prognosis after surgery and AED withdrawal. This paper raised this issue. Little is known about natural history of MTLE in population-based studies (Berg, 2008) and it is possible that, in some patients, epilepsy becomes less refractory over the years. With study of less-selected series of patients and not only those in epilepsy surgery centers, it has been observed that in the heterogeneous group of MTLE, even with HS, many patients have favorable outcomes and remission with and without AEDs (Labate et al., 2006; Aguglia et al., 2011). Most of these patients respond to the first AED and are not candidates for surgery (Labate et al., 2011), but a few of them require a second AED (Aguglia et al., 1998), and it is possible that these patients who would improve even without surgery, were included in this and other series of patients submitted to ATL, misleading to the view that earlier surgeries are responsible for better results regarding postsurgical AED withdrawal. Finally, what is known as MTLE in tertiary centers, where ATL is performed, probably represents the final outcome of multiple etiologies. Recognizing different pathogenic processes leading to this epilepsy will improve decisions about the best age for surgery. I have no conflicts of interest to disclose. I have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.