Kristina Malmgren, Sallie Baxendale and J. Helen Cross (eds.)Long-Term Outcomes of Epilepsy Surgery in Adults and Children10.1007/978-3-319-17783-0_19

19. Long-Term Outcomes of Epilepsy Surgery: Knowledge Gaps and Future Directions

Kristina Malmgren^{1, 2}, Sallie Baxendale³, J. Helen Cross⁴ and Philippe Ryvlin⁵

(1)

Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden

(2)

Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden

(3)

Department of Clinical and Experimental Epilepsy, National Hospital for Neurology and Neurosurgery, London, UK

(4)

Section of Clinical Neuroscience, UCL-Institute of Child Health, Great Ormond Street Hospital & Young Epilepsy, 4/5 Long Yard, WC1N 3LU London, UK

(5)

Department of Clinical Neurosciences, Centre Hospitalo-Universitaire Vaudois, Lausanne, Switzerland

Kristina Malmgren

Email: Kristina.malmgren@neuro.gu.se

Abstract

Although epilepsy surgery has long been recognized as an effective treatment for carefully selected adults and children, studies of long-term seizure control are relatively rare and studies of the wider aspects of surgical outcome are even more scarce. In summarizing the literature, many of the chapters in this volume have highlighted what we do not know about epilepsy surgery outcomes rather than what we do. This chapter highlights the gaps in the adult and pediatric literature and discusses the roles that networking, collaboration, and adherence to a basic set of standards may play in addressing the current shortcomings of the literature.

Keywords

NetworkingCollaborationMulticenter studies

The chapters in this volume have reviewed the long-term outcomes of epilepsy surgery in both pediatric and adult populations. Although epilepsy surgery has long been recognized as an effective treatment for carefully selected adults and children (see Chapter 1), studies of long-term seizure control are relatively rare and studies of the wider aspects of surgical outcome are even more scarce. In summarizing the literature, many of the chapters in this volume have highlighted what we do not know about epilepsy surgery outcomes rather than what we do. The literature reviewed in this volume has a direct impact on what we as clinicians should tell potential surgical candidates about the procedure. Unlike some surgeries in other branches of medicine, epilepsy surgery outcomes are dynamic and not fixed at the 1-year follow-up time point. The oft quoted chances of being seizure-free at 1 year (60–70 %) do not tell the whole story. Long-term outcome studies suggest that less than 50 % of adults will remain seizure-free after surgery in the long term (see Chap. 3). The odds of achieving and sustaining seizure freedom are not the same thing. It is imperative that the long-term perspective forms an integral part of presurgical counseling of prospective surgical candidates. Similarly, Chaps. 10, 11, 12, 13, 14, and 15 highlight the wider aspects of surgical outcome that must be addressed in both the examination of preoperative expectations and the maximization of the postoperative opportunities that improved seizure control can bring, but are by no means automatic.

Knowledge Gaps in the Adult Literature

As discussed in Chap. 3, the best longitudinal long-term seizure outcome data in adults concern those who have had temporal lobe resection. There is much less information on the longitudinal course in other patient cohorts. For many resection types, the numbers of patients in single-center long-term studies are limited and for almost all studies there is a lack of controls. Multicenter observational studies following both operated and nonoperated patients are needed in order to obtain more robust data on long-term seizure outcomes.

Similarly, the literature on the long-term changes in cognitive function in people who undergo epilepsy surgery is small and currently limited to series that have undergone temporal lobe resections. Longitudinal studies suggest that the majority of epilepsy surgery candidates have stable memory functions at assessments conducted more than 5 years after surgery, with scores comparable to those they obtained 12–24 months after the operation. However, there is a subset of patients in whom ongoing seizures are associated with progressive memory impairment. Group data obscure individual trajectories of change, which can vary widely. Neuropsychological outcomes must be considered within the context of the individual patients’ capacity for decline at the preoperative assessment.

There are no data on the long-term psychiatric outcomes of epilepsy surgery patients. Given the fluctuating nature of psychiatric conditions, longitudinal, routine clinical follow-up of surgical patients is the only way to track individual trajectories in mental health following surgery. In the shorter term, postsurgical depression and/or anxiety disorders are the most frequent psychiatric disorders identified after resective epilepsy surgery. A presurgical psychiatric history has been found to be associated with an increased risk of postsurgical recurrences or exacerbations. In a majority of patients, symptoms are expected to remit by 1 year, though persistent psychopathology has been found in up to 15 % of patients.

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