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Brain Advance Access originally published online on November 22, 2006
Brain 2007 130(2):334-345; doi:10.1093/brain/awl316
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© The Author (2006). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

Review Articles

Long-term outcomes in epilepsy surgery: antiepileptic drugs, mortality, cognitive and psychosocial aspects

José F. Téllez-Zenteno1,3, Rajat Dhar2, Lizbeth Hernandez-Ronquillo1 and Samuel Wiebe1

1 Department of Clinical Neurosciences. University of Calgary Calgary, Alberta, Canada 2 Department of Neurology. Washington University School of Medicine St Louis, MO, USA 3 Department of Neurology. Instituto Nacional de Ciencias Médicas y Nutrición ‘Salvador Zubirán’ Mexico City, Mexico

Correspondence and reprint requests to: Dr Samuel Wiebe, Division of Neurology, Foothills Medical Centre, 1403-29 St N.W., Calgary, Alberta, Canada T2N 2T9 Email: swiebe{at}ucalgary.ca


    Summary
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Assessment of long-term outcomes is essential in brain surgery for epilepsy. Little information exists on long-term non-seizure outcomes after epilepsy surgery. We perform a systematic review and meta-analysis of the evidence on this topic. Our aim was to provide evidence-based estimates of antiepileptic drug, psychosocial, neuropsychological and mortality long-term outcomes following epilepsy surgery, and to identify sources of variation in published results. We searched Medline, Index Medicus, the Cochrane database, bibliographies of reviews, original articles, and book chapters, to identify articles published from 1991 to 2005, containing ≥20 patients of any age, undergoing resective or non-resective epilepsy surgery, and followed for a mean/median of ≥5 years. Two reviewers independently assessed study eligibility and extracted data, resolving disagreements through discussion. Standard meta-analytical techniques were used to pool data. Of the 159 potentially eligible articles reviewed in full-text, 35 (22%) fulfilled eligibility criteria; 6 (17%) were controlled studies; 15 (36%) explored antiepileptic drug outcome; 6 (17%) explored mortality; 11 (31%) reported psychosocial outcomes; and 7 (20%) explored neuropsychological outcomes. On an average, 14% [95% confidence interval (CI95) = 11–17] of the patients with temporal lobe surgery achieved long-term antiepileptic drug (AED) discontinuation, 50% (CI95 = 45–55) achieved monotherapy, and 33% remained on polytherapy (CI95 = 29–38). In analyses including all types of surgery, on average, 20% (CI95 = 18–23) achieved long-term AED discontinuation, while 41% (CI95 = 37–45) were on monotherapy and 31% (CI95 = 27–35) remained on polytherapy. Children achieved better AED outcomes than adults. Seizure freedom after surgery was associated with lower mortality, but inconsistent mortality outcomes precluded making strong inferences. Non-controlled studies consistently reported improved long-term psychosocial outcomes, but the effect was less clear in controlled studies. Intelligence was unchanged by surgery, but long-term memory outcomes were associated with seizure freedom and side of temporal lobe resection. Few long-term, controlled studies exist. Longer follow-up was associated with lower rates of AED discontinuation, reflecting lower seizure-free rates over time. Cognitive and psychosocial outcomes were similar to those of short-term studies, and the results were influenced by the presence of controls.

Key Words: antiepileptic drugs; controlled studies; epilepsy surgery; long-term outcome; mortality

Abbreviations: AEDs, antiepileptic drugs; CI95, 95% confidence interval

Received May 24, 2006. Revised October 10, 2006. Accepted October 13, 2006.


    Introduction
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Assessment of long-term outcomes is essential in epilepsy, in general, and in epilepsy surgery, in particular (Spencer, 1996Go). While earlier studies traditionally focused on relatively short outcomes, epilepsy surgery centres are now reporting long-term outcomes in cohorts of patients with epilepsy following a variety of surgical interventions. Recently we published a systematic review and meta-analysis focusing on seizure outcome in studies with long-term (≥5 years) follow-up (Tellez-Zenteno et al., 2005aGo). The long-term seizure-free rate following temporal lobe resective surgery was similar to that reported in short-term controlled studies (Wiebe et al., 2001Go; Engel et al., 2003Go). On the other hand, long-term seizure freedom was consistently lower after extratemporal surgery and palliative procedures (Tellez-Zenteno et al., 2005aGo).

However, it has been long recognized that seizure outcomes are but one element of epilepsy surgery outcomes. Penfield and Paine (1955)Go pointedly stated that ‘It is not enough whether a radical surgery procedure has stopped attacks or not. We must know its effect upon the patient's ability to work, to hold a job, to study; the effect on physical and mental function, the effect on behaviour and on the happiness of the patient and friends.' In recent years the assessment of outcomes other than seizures has helped us understand the effect of epilepsy surgery on other spheres (Gleissner et al., 1999Go; Wiebe, 2006Go). Studies reporting measures of quality of life, patient's preferences and disability in epilepsy have shown that the magnitude of the adverse effects of recurrent seizures is as large as that seen with diabetes and active cardiovascular disease (Gleissner et al., 1999Go; Tellez-Zenteno et al., 2005bGo). Studies focusing on short-term outcomes, including the only randomized clinical trial of surgery in temporal lobe epilepsy (Wiebe et al., 2001Go), have shown that epilepsy surgery improves quality of life and health status (Markand et al., 2000Go; Gilliam, 2003Go; Wiebe, 2006Go).

We performed a systematic review and meta-analysis of the evidence on long-term outcomes other than seizures, including antiepileptic drugs (AEDs), mortality, neuropsychological and psychosocial outcomes. Our aim is to provide clinicians with a scientifically valid and coherent summary of the best current evidence.


    Material and methods
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Data sources
A medical librarian performed a comprehensive literature search of the Medline®, Embase®, Index Medicus®, and Cochrane databases (Medline search strategy in Appendix 1). We also searched bibliographies of reviews, original articles and book chapters, and consulted experts about other studies. Literature searches were restricted to full-length English articles published between January 1991 and June 2005.

Study selection and classification
Two reviewers independently applied the following study inclusion criteria: reports of ≥20 patients of any age undergoing resective or non-resective epilepsy surgery, outcomes reported after a mean/median follow-up of ≥5 years, quantitative report of seizure and other outcomes, and description of type of surgery and number of patients undergoing each intervention. We excluded studies with any overlapping patient populations from the same centre. The outcomes explored included AEDs, psychosocial aspects, neuropsychological function and mortality. We distinguished between controlled and non-controlled studies. For AED outcomes we explored the proportion of patients on monotherapy, polytherapy, free of AEDs and patients cured after epilepsy surgery (off AEDs and seizure-free).

Data gathering
Two reviewers independently abstracted all data, resolving disagreements through discussion. We accepted outcome definition as used by authors in each study. These usually referred to patients' health status during the last recorded follow-up, without specifying its duration.

Analysis
Studies were the unit of analysis. Some articles contributed more than one study. Only AED outcomes were amenable to statistical pooling, which was done in the categories stated above, weighing studies by the inverse of their variance. We used Wilson's method to compute 95% confidence intervals (CI95) around pooled proportions (Newcombe and Altman, 2003Go). Statistical heterogeneity was assessed with the {chi}2 test. We also obtained the median proportion, and the interquartile range (25th and 75th percentile). Studies whose results were outside the interquartile range were judged to be clinically heterogeneous and a potential source for heterogeneity was sought in each instance. For other outcomes we provide descriptive analyses and tabulate the main findings.


    Results
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Evidence base
The literature search yielded 1794 references, of which 159 (9%) were potentially eligible and were reviewed in full text independently by two reviewers. Thirty five studies (22%) fulfilled the eligibility criteria and constitute this analysis' dataset (Fig. 1). Some articles contributed to more than one outcome. Fifteen (36%) studies reported on AED outcomes, six (17%) explored mortality, eleven (31%) reported various psychosocial outcomes and seven (20%) explored neuropsychological function (Appendix 2). We identified six controlled studies; none were randomized (Table 1). In three studies the controls were patients not evaluated for surgery at the time of matching (Vickrey et al., 1995Go; Altshuler et al., 1999Go; Jones et al., 2002Go), in two they were patients evaluated for surgery but not operated (Guldvog et al., 1991aGo, bGo; Helmstaedter et al., 2003Go), and one study did not describe surgical eligibility of their control group (Stavem and Guldvog, 2005Go).


Figure 1
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Fig. 1 Results of literature search. Number of included and excluded studies and categories of analysis.

 


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Table 1 Controlled studies (n = 6) with long-term follow up (509 medical and 799 surgical patients)

 
AED outcomes (Table 2) (Fig. 2A–D)
Fifteen studies evaluated long-term AED outcomes, of which four had a medical control group (Appendix 2). Analyses including all types of surgery (n = 15; Table 2) showed that 20% (CI95 = 18–23) of patients were free of medication without specifying seizure outcome. The corresponding proportion was 41% (CI95 = 37–45) for monotherapy and 31% for polytherapy (CI95 = 27–35). For all types of surgery, the pooled proportion of patients who were seizure-free and off AEDs (n = 9 studies) was 22% (CI95 = 20–25). In 10 studies of temporal lobe surgery 14% (CI95 = 11–17) of patients were free of AEDs without specifying seizure outcome. The corresponding proportion was 50% (CI95 = 45–55) for monotherapy and 33% (CI95 = 29–38) for polytherapy. The pooled proportion of patients who were seizure-free and off AEDs was 20% (CI95 = 17–23). AED outcomes seemed superior in studies that did not focus on temporal lobe surgery (n = 5), the proportion of patients who were seizure-free and off AEDs was 36 (CI95 = 31–41). This category included two studies on hemispherectomy, which reported better outcomes (Kossoff et al., 2003Go; Pulsifer et al., 2004Go). Studies focusing on children (Appendix 2; n = 6) had overall better AED outcomes than adults (n = 9; Table 2) and 27% (CI95 = 23–31) of children were seizure-free and off AEDs, as compared to 19% (CI95 = 16–22) of adults (P < 0.05).


Figure 2
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Fig. 2 Proportion of patients with various long-term AED outcomes including all types of surgery. Individual studies are depicted with their corresponding CI95. Solid horizontal lines represent the median proportion, and dotted lines the 25th and 75th percentiles. Studies outside these percentiles were judged as clinically heterogeneous and are described for each group. (A) Patients with all types of surgeries who were seizure-free and off AEDs (9 studies, n = 936). The pooled proportion was 22% (CI95 = 20–25%). The median proportion was 22% (25th and 75th percentiles 20 and 37%). The study below the 25th percentile involved temporal epilepsy and reported lower seizure-free rates in very long follow-up (Salanova et al., 1999Go). One of the two studies above the 75% percentile had no more than 5 years of follow-up (Kim et al., 2005Go) and the other focused on hemispherectomy, both associated with better outcomes (Kossoff et al., 2003Go). (B) Proportion of patients off AEDs, without specifying seizure-free status (11 studies, n = 904). The pooled proportion of AED-free patients was 20% (CI95 = 18–23). The median proportion was 25% (25th and 75th percentiles 18 and 39%). Of the three studies below the 25th percentile, one involved extratemporal surgery (Adler et al., 1991Go) and two involved temporal surgery with longer follow-up (Salanova et al., 1999Go; Helmstaedter et al., 2003Go), both associated with poorer outcomes. Two of the three studies above the 75% percentile were in hemispherectomy (Kossoff et al., 2003Go; Pulsifer et al., 2004Go) and one had follow-up no longer than 5 years (Mathern et al., 1999Go). (C) Patients on monotherapy (7 studies, n = 566). The pooled proportion was 41% (CI95 = 37%, 45%). The median proportion was 39% (25th and 75th percentiles 27 and 51%). Of two studies below the 25th percentile, one was on hemispherectomy, in which many patients were seizure-free and off AEDs (Kossoff et al., 2003Go), and the other reported very long follow-up (27 years) following temporal and extemporal surgery (Guldvog et al., 1991c). The two studies above the 75% percentile were in temporal lobe surgery with prolonged follow-up (Salanova et al., 1999Go; Helmstaedter et al., 2003Go). (D) Patients on polytherapy (7 studies, n = 566). The pooled proportion of seizure-free patients was 31% (CI95 = 27–35). The median proportion was 33% (25th and 75th percentiles 25 and 38%). One study on hemispherectomy was below the 25th percentile and reported a large proportion of seizure-free patients (Kossoff et al., 2003Go). The study above the 75% percentile reported very long follow-up in patients with temporal and extratemporal epilepsy (Guldvog et al., 1991c).

 


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Table 2 Long-term AED outcomes: overall proportion by group of interest

 
Four of six controlled studies explored long-term AED outcomes and found a lower use of AEDs in surgically treated patients than in controls (Table 1) (Guldvog, et al., 1991bGo; Vickrey et al., 1995Go; Altshuler et al., 1999Go; Helmstaedter et al., 2003Go). Two of these studies contained sufficient information to compute pooled statistics in medically treated patients (Guldvog et al., 1991bGo; Helmstaedter et al., 2003Go). The pooled proportion of patients free of AEDs was 0%, while 24% were on monotherapy (CI95 = 16–27) and 75% on polytherapy (CI95 = 71–83).

Psychosocial outcomes (Table 3)
Eleven non-controlled studies evaluated long-term psychosocial outcomes (Appendix 2). Seven (63%) dealt with temporal lobe epilepsy surgery (Erba et al., 1992Go; Sperling et al., 1995Go; Eliashiv et al., 1997Go; Sirven et al., 2000Go; Lowe et al., 2004Go; Paglioli et al., 2004Go; Reid et al., 2004Go), one (9%) with callosotomy (Sakas and Phillips, 1996Go), one (9%) with hemispherectomy (Pulsifer et al., 2004Go), and two (18%) with temporal and extratemporal lobe surgery(Wass et al., 1996Go; Keene et al., 1997Go). Numerous outcomes were evaluated; most consistently driving status, quality of life, educational and employment status, interpersonal relationships and social behaviour. All of these studies reported favourable long-term psychosocial outcomes following surgery. Five of these studies (45%) (Sperling et al., 1995Go; Eliashiv et al., 1997Go; Keene et al., 1997Go; Lowe et al., 2004Go; Reid et al., 2004Go) compared long-term psychosocial function in seizure free and not seizure free patients. All studies in this category reported improved psychosocial function following surgery in seizure free patients. Five (45%) studies (Erba et al., 1992Go; Sakas and Phillips, 1996Go; Wass et al., 1996Go; Sirven et al., 2000Go; Paglioli et al., 2004Go) compared long-term post-surgical psychosocial outcome before and after surgery. Outcomes were consistently better after surgery. One (10%) study reported improved post-surgical psychosocial outcome without reference to seizure outcome (Pulsifer et al., 2004Go). Two controlled studies explored long-term psychosocial outcomes in surgical and medical controls and found no differences (Vickrey et al., 1995Go; Helmstaedter et al., 2003Go) (Table 1). Finally, two controlled studies documented a lower long-term prevalence of depression in surgically than in medically treated patients (Altshuler et al., 1999Go; Helmstaedter et al., 2003Go) (Table 1).


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Table 3 Long-term non-controlled studies evaluating post-surgical psychosocial outcomes (n = 11)

 
Mortality (Table 4)
Six studies reported long-term post-surgical mortality rates. Three studies compared mortality in surgically versus medically treated patients. Two of these studies (Guldvog, et al., 1991bGo; Stavem and Guldvog, 2005Go) found no differences, and one found decreased mortality in surgical patients (Vickrey, et al., 1995Go). Information is difficult to interpret in two of the studies because of limited information (Guldvog et al., 1991bGo; Vickrey, et al., 1995Go). Only Stavem and Guldvog (2005)Go reported mortality ratios and person-years of follow-up. Three studies explored mortality after surgery according to seizure outcome and side of surgical resection. Two (Sperling et al., 1999Go; Salanova et al., 2002Go) found lower mortality rates in seizure-free patients compared with patients with recurrent seizures. One study found a higher mortality rate in patients with right temporal lobe resections only among those with mesial temporal sclerosis. It also found that epilepsy surgery lowers, but does not normalize mortality ratios when compared with the general population (Hennessy et al., 1999Go).


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Table 4 Studies exploring mortality (n = 6; 1449 surgical patients)

 
Neuropsychological outcomes (Table 5)
Seven studies explored neuropsychological outcomes. Five (Keogan et al., 1992Go; Kirkpatrick et al., 1993Go; Helmstaedter et al., 2003Go; Alpherts et al., 2004Go; Paglioli et al., 2004Go) reported on temporal lobe surgery, one on extratemporal surgery (Bizzi et al., 1997Go), and one on hemispherectomy (Pulsifer et al., 2004Go). Five studies evaluating intelligence consistently reported no long-term post-surgical worsening in intelligence scores (Keogan et al., 1992Go; Kilpatrick et al., 1992Go; Bizzi et al., 1997Go; Alpherts et al., 2004Go; Pulsifer et al., 2004Go), and one reported slight improvement following right temporal lobe resection (Keogan et al., 1992Go). Three studies have reported long-term memory outcomes. Two of these documented a greater decline in memory function after left than after right temporal lobe resection (Helmstaedter et al., 2003Go; Paglioli et al., 2004Go). A small study showed memory decline in 33% of patients independent of the side of resection (Kirkpatrick et al., 1993Go). The only study with medical controls exploring long-term memory function showed that overall, more patients worsened after surgery (60%) than with medical therapy (50%) (Helmstaedter et al., 2003Go).


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Table 5 Neuropsychological outcome in studies with long-term follow-up (n = 6)

 

    Discussion
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Long-term epilepsy surgery outcomes other than seizures are infrequently explored. This overview and meta-analysis of the best available evidence identifies differences and similarities between long- and short-term outcomes, and points to important gaps in our knowledge.

Schmidt and Löscher (2003)Go systematically analysed overall AED outcomes after temporal epilepsy surgery including many studies with shorter follow-up. One-third of patients were cured (seizure-free without AEDs), one-third was controlled with AEDs, and one-third continued to have recurrent disabling seizures despite AEDs. The same authors performed a second review in 2004 using studies with longer follow-up to explore AED outcomes in temporal lobe epilepsy surgery (Schmidt et al., 2004Go). The percentage of cured patients was lower than in short-term studies, 25% in adults and 31% in children. In our long-term analysis, only 16% of temporal lobe surgery patients and 18% of those undergoing all types of surgery were cured. The lower proportion of optimum outcomes in our analysis may be explained by our use of more stringent selection criteria that included only studies with >5 years of follow-up. Thus, there is consistent convergent evidence that early AED and seizure post-operative outcomes tend to decline over time (Tellez-Zenteno et al., 2005aGo).

The inverse association between duration of follow-up and proportion of patients discontinuing AEDs is also evident in our analysis. Duration of follow-up at the extremes (barely 5 years, versus very long follow-up) explained some of the clinically heterogeneous and extreme results in our analyses (Fig. 2). Importantly, none of the medically treated patients in the control groups in our meta-analysis discontinued AEDs, and the majority was on polytherapy. That children had better AED outcomes may reflect that children had more extensive and effective surgical resections (e.g. hemispherectomies), but it may also suggest that earlier surgery may offer a better chance of curing epilepsy.

A clear notion of the impact of surgery on mortality in epilepsy is important for physicians and patients alike (Tomson et al., 2004Go; Ryvlin et al., 2005Goa; Sperling et al., 2005Go). We found conflicting data in this regard (Table 3). One controlled study found an improvement in mortality rates after surgery (Vickrey et al., 1995Go), but two studies (Guldvog et al., 2005Go) did not. Methodological heterogeneity may contribute to the differences. For example seizure outcomes at last follow-up are not always well described, and control groups are dissimilar among studies. The intriguing association between higher mortality rates and right temporal lobe resections observed in one long-term study (Hennessy et al., 1999Go) is consistent with similar results from short-term studies (Salanova et al., 2002Go; Nilsson et al., 2003Go). The cause for this finding is not known. Explanations offered include an asymmetric cardiac arrhythmogenesis of either temporal lobe, bimesial temporal involvement (Rossetti et al., 2005Go), more extensive epileptogenicity and structural abnormalities in right temporal lobe epilepsy, and different prevalence rates of mesial temporal sclerosis in right and in left temporal lobe cases (Nilsson et al., 2003Go). In general, it appears that the long-term mortality rate is lower in patients rendered seizure-free after epilepsy surgery, but there are no consistent data or general consensus in this regard (Ryvlin and Kahane 2003Go; Ryvlin et al., 2005aGo). There is a notion that lower mortality rate in seizure-free patients after surgery could decrease sudden unexpected death in epilepsy, which is responsible for a considerable proportion of deaths in patients with refractory epilepsy (Tellez-Zenteno et al., 2005cGo). However, it remains to be determined whether the baseline risk of death is also lower in surgical candidates, as compared with patients who are not eligible for surgery.

Chronic epilepsy generally impairs cognition, and also induces processes of functional reorganization and behavioural compensations (Elger et al., 2004Go). Poor cognitive outcome is generally associated with early onset, long duration and poor seizure control (Helmstaedter et al., 2003Go). Only seven studies reporting cognitive outcomes had a minimal follow-up of 5 years and almost all involved temporal lobe epilepsy. Overall, long-term cognitive outcomes are similar to those in studies reporting short-term follow-up, indicating that cognitive outcomes are sustained after surgery. In general, they indicate that successful epilepsy surgery can halt or improve the cognitive decline seen in chronic epilepsy, and that left temporal resections have a higher risk of additional post-operative verbal memory impairment (Ojemann and Dodrill, 1985Go; Davies et al., 1996Go, 1998Go).

The ultimate goal of surgery is to improve the significant psychosocial impairments affecting people with refractory epilepsy (Jensen, 1972Go; Rodin et al., 1972Go; Dikmen and Morgan, 1980Go). Eleven non-controlled studies analysed long-term psychosocial outcomes. Although all the studies reported better outcomes after epilepsy surgery, the absence of controls in many studies weakens their validity, especially with regard to the magnitude of the effects of surgery. For example, some controlled studies failed to show differences in psychosocial outcomes between surgically and medically treated patients (Vickrey et al., 1995Go; Helmstaedter et al., 2003Go). Nonetheless, these data are still valuable because they can inform the long benefits of surgery in non-seizure outcomes, and the rarity of worsening as a result of surgery in the long term. Psychiatric and somatic comorbidity is highly prevalent in patients with epilepsy (Gaitatzis et al., 2004Go; Tellez-Zenteno et al., 2005bGo).

Traditionally, studies assessing psychosocial function emphasize seizures as the major predictor of outcomes. It is crucial to undertake studies that can help us understand the role of various comorbidities on the patients' social, psychological and functional outcomes following surgery.

The lack of adequate controls is a major weakness of most epilepsy surgery studies (Engel et al., 2003Go). We identified only six controlled studies on long-term surgical outcomes, which can be considered as the best available evidence of our dataset. However, most of these were retrospective studies and few satisfied the validity criteria required of cohort studies (Laupacis et al., 1994Go). Controls varied substantially among studies. In many studies they were surgical candidates, in others they were not eligible for surgery, and some studies did not describe this adequately (See Table 1). This underscores the fact that controls were not equivalent among studies, and also differed considerably from the surgical groups. Moreover, the heterogeneity of outcome ascertainment methods varied among studies (telephone calls, charts review, hospital assessment, database review, and others). These deficiencies lower the strength of inference that can be derived from these studies and underscore the need for systematic, long-term cohort studies using standard methodology.


    Appendix 1
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Literature Search Strategy (Medline)

1. First step

‘Epilepsy/surgery’ [MeSH] OR (‘epilepsy’ [TW] AND ‘surgery’ [TW])

2. Second step

‘Incidence’ [MeSH] OR ‘Mortality’ [MeSH] OR ‘mortality’ [SH] OR ‘Follow-Up Studies’ [MeSH] OR ‘Prognosis’ [MeSH:NOEXP] OR ‘prognos*’ [TW] OR ‘predict*’ [TW] OR ‘course’ [TW] OR ‘outcome’ [TW] OR ‘psychology’ [TW] OR ‘Quality of Life’ [MeSH] OR ‘Quality of Life’ [TW] OR memory [TW] OR ‘Survival Analysis’ [MeSH:NOEXP]

3. Third step

‘randomized controlled trial’ [PTYP] OR ‘random*’ [TW] OR (‘double’ [TW] AND ‘blind*’ [TW]) OR ‘placebo’ [TW] OR ‘drug therapy’ [SH] OR ‘therapeutic use’ [SH:NOEXP] OR ‘cohort studies’ [MeSH] OR ‘risk’ [MeSH] OR (‘odds’ [TW] AND ‘ratio*’ [TW]) OR (‘relative’ [TW] AND ‘risk’ [TW]) OR ‘case–control*’ [TW] OR ‘case-control studies’ [MeSH]

4. Fourth step

#1 AND #2 AND #3

5. Fifth step: Limits

Publication Year 1991–2005

Human

Journal article


    Appendix 2
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Articles contributing to specific analyses in the systematic review

Antiepileptic drugs
[Adler et al., 1991Go; Elwes et al., 1991Go; Guldvog et al., 1991bGo; Guldvog et al., 1994Go; Sperling et al., 1996; Mathern et al., 1999Go; Salanova et al., 1999Go; Helmstaedter et al., 2003Go; Kossoff et al., 2003Go; Wieser and Hane, 2003Go; Kim et al., 2004Go; Lowe et al., 2004Go; McIntosh et al., 2004Go; Pulsifer et al., 2004Go; Reid et al., 2004Go]

Psychosocial function
[Erba et al., 1992Go; Sperling et al., 1995Go; Sakas and Phillips, 1996Go; Wass et al., 1996Go; Eliashiv et al., 1997Go; Keene et al., 1997Go; Sirven et al., 2000Go; Lowe et al., 2004Go; Paglioli et al., 2004Go; Pulsifer et al., 2004Go; Reid et al., 2004Go]

Mortality
[Guldvog et al., 1991aGo; Vickrey et al., 1995Go; Hennessy et al., 1999Go; Sperling et al., 1999Go; Salanova et al., 2002Go; Stavem and Guldvog, 2005Go]

Neuropsychological function
[Keogan et al., 1992Go; Kilpatrick et al., 1992Go; Bizzi et al., 1997Go; Helmstaedter et al., 2003Go; Alpherts et al., 2004Go; Paglioli et al., 2004Go; Pulsifer et al., 2004Go]

Controlled studies
[Guldvog et al., 1991aGo, bGo; Vickrey et al., 1995Go; Altshuler et al., 1999Go; Jones et al., 2002Go; Helmstaedter et al., 2003Go; Stavem and Guldvog, 2005Go]

Studies in children and adolescents exploring AED outcomes
[Adler J et al., 1991Go; Guldvog et al., 1994Go; Kossoff et al., 2003Go; Mathern et al., 1999Go; McIntosh et al., 2004Go; Pulsifer et al., 2004Go]


    Acknowledgements
 
Jan Figurski (Library services-London Health Sciences Center) assisted with the literature search.


    References
 Top
 Summary
 Introduction
 Material and methods
 Results
 Discussion
 Appendix 1
 Appendix 2
 References
 
Adler J, Erba G, Winston KR, Welch K, Lombroso CT. (1991) Results of surgery for extratemporal partial epilepsy that began in childhood. Arch Neurol 48:133–40.[Abstract/Free Full Text]

Alpherts WC, Vermeulen J, Hendriks MP, Franken ML, van Rijen PC, Lopes da Silva FH, et al. (2004) Long-term effects of temporal lobectomy on intelligence. Neurology 62:607–11.[Abstract/Free Full Text]

Altshuler L, Rausch R, Delrahim S, Kay J, Crandall P. (1999) Temporal lobe epilepsy and temporal lobectomy, and major depression. J Neuropsychiatry Clin Neurosci 11:436–43.[Abstract/Free Full Text]

Bizzi JW, Bruce DA, North R, Elterman R, Linder S, Porter-Levy S, et al. (1997) Surgical treatment of focal epilepsy in children: results in 37 patients. Pediatr Neurosurg 26:83–92.[Web of Science][Medline]

Davies KG, Hermann BP, Dohan FC Jr, Wyler AR. (1996) Intractable epilepsy due to meningitis: results of surgery and pathological findings. Br J Neurosurg 10:567–70.[CrossRef][Web of Science][Medline]

Davies KG, Bell BD, Bush AJ, Wyler AR. (1998) Prediction of verbal memory loss in individuals after anterior temporal lobectomy. Epilepsia 39:820–8.[CrossRef][Web of Science][Medline]

Dikmen S and Morgan SF. (1980) Neuropsychological factors related to employability and occupational status in persons with epilepsy. J Nerv Ment Dis 168:236–40.[Web of Science][Medline]

Elger CE, Helmstaedter C, Kurthen M. (2004) Chronic epilepsy and cognition. Lancet Neurol 3:663–72.[CrossRef][Web of Science][Medline]

Eliashiv SD, Dewar S, Wainwright I, Engel J Jr, Fried I. (1997) Long-term follow-up after temporal lobe resection for lesions associated with chronic seizures. Neurology 48:1383–8.[Abstract/Free Full Text]

Elwes RD, Dunn G, Binnie CD, Polkey CE. (1991) Outcome following resective surgery for temporal lobe epilepsy: a prospective follow up study of 102 consecutive cases. J Neurol Neurosurg Psychiatry 54:949–52.[Abstract/Free Full Text]

Engel J Jr, Wiebe S, French J, Sperling M, Williamson P, Spencer D, et al. (2003) Practice parameter: temporal lobe and localized neocortical resections for epilepsy: report of the Quality Standards Subcommittee of the American Academy of Neurology, in association with the American Epilepsy Society and the American Association of Neurological Surgeons. Neurology 60:538–47.[Abstract/Free Full Text]

Erba G, Winston KR, Adler JR, Welch K, Ziegler R, Horning GW. (1992) Temporal lobectomy for complex partial seizures that began in childhood. Surg Neurol 38:424–32.[CrossRef][Web of Science][Medline]

Gaitatzis A, Carroll K, Majeed A, Sander W. (2004) The epidemiology of the comorbidity of epilepsy in the general population. Epilepsia 45:1613–22.[CrossRef][Web of Science][Medline]

Gilliam F. (2003) The impact of epilepsy on subjective health status. Curr Neurol Neurosci Rep 3:357–62.[Medline]

Gleissner U, Johanson K, Helmstaedter C, Elger CE. (1999) Surgical outcome in a group of low-IQ patients with focal epilepsy. Epilepsia 40:553–9.[Web of Science][Medline]

Guldvog B, Loyning Y, Hauglie-Hanssen E, Flood S, Bjornaes H. (1991a) Surgical versus medical treatment for epilepsy. II. Outcome related to social areas. Epilepsia 32:477–86.[Web of Science][Medline]

Guldvog B, Loyning Y, Hauglie-Hanssen E, Flood S, Bjornaes H. (1991b) Surgical versus medical treatment for epilepsy. I. Outcome related to survival, seizures, and neurologic deficit. Epilepsia 32:375–88.[Web of Science][Medline]

Guldvog B, Loyning Y, Hauglie-Hanssen E, Flood S, Bjornaes H. (1994) Surgical treatment for partial epilepsy among Norwegian children and adolescents. Epilepsia 35:554–65.[CrossRef][Web of Science][Medline]

Helmstaedter C, Kurthen M, Lux S, Reuber M, Elger CE. (2003) Chronic epilepsy and cognition: a longitudinal study in temporal lobe epilepsy. Ann Neurol 54:425–32.[CrossRef][Web of Science][Medline]

Hennessy MJ, Langan Y, Elwes RD, Binnie CD, Polkey CE, Nashef L. (1999) A study of mortality after temporal lobe epilepsy surgery. Neurology 53:1276–83.[Abstract/Free Full Text]

Jensen I. (1972) Social conditions of temporal lobe epileptics in Denmark. Epilepsia 13:71–4.[Web of Science][Medline]

Jones JE, Berven NL, Ramirez L, Woodard A, Hermann BP. (2002) Long-term psychosocial outcomes of anterior temporal lobectomy. Epilepsia 43:896–903.[CrossRef][Web of Science][Medline]

Keene DL, Higgins MJ, Ventureyra EC. (1997) Outcome and life prospects after surgical management of medically intractable epilepsy in patients under 18 years of age. Childs Nerv Syst 13:530–5.[CrossRef][Web of Science][Medline]

Keogan M, McMackin D, Peng S, Phillips J, Burke T, Murphy S, et al. (1992) Temporal neocorticectomy in management of intractable epilepsy: long-term outcome and predictive factors. Epilepsia 33:852–61.[CrossRef][Web of Science][Medline]

Kilpatrick CJ, Davis SM, Hopper JL, Rossiter SC. (1992) Early seizures after acute stroke. Risk of late seizures. Arch Neurol 49:509–11.[Abstract/Free Full Text]

Kim YD, Heo K, Park SC, Huh K, Chang JW, Choi JU, et al. (2005) Antiepileptic drug withdrawal after successful surgery for intractable temporal lobe epilepsy. Epilepsia 46:251–7.[CrossRef][Web of Science][Medline]

Kirkpatrick PJ, Honavar M, Janota I, Polkey CE. (1993) Control of temporal lobe epilepsy following en bloc resection of low-grade tumors. J Neurosurg 78:19–25.[Web of Science][Medline]

Kossoff EH, Vining EP, Pillas DJ, Pyzik PL, Avellino AM, Carson BS, et al. (2003) Hemispherectomy for intractable unihemispheric epilepsy etiology vs. outcome. Neurology 61:887–90.[Abstract/Free Full Text]

Laupacis A, Wells G, Richardson WS, Tugwell P. (1994) Users' guides to the medical literature. V. How to use an article about prognosis. Evidence-Based Medicine Working Group. JAMA 272:234–7.[Abstract/Free Full Text]

Lowe AJ, David E, Kilpatrick CJ, Matkovic Z, Cook MJ, Kaye A, et al. (2004) Epilepsy surgery for pathologically proven hippocampal sclerosis provides long-term seizure control and improved quality of life. Epilepsia 45:237–42.[CrossRef][Web of Science][Medline]

Markand ON, Salanova V, Whelihan E, Emsley CL. (2000) Health-related quality of life outcome in medically refractory epilepsy treated with anterior temporal lobectomy. Epilepsia 41:749–59.[CrossRef][Web of Science][Medline]

Mathern GW, Giza CC, Yudovin S, Vinters HV, Peacock WJ, Shewmon DA, et al. (1999) Postoperative seizure control and antiepileptic drug use in pediatric epilepsy surgery patients: the UCLA experience, 1986–1997. Epilepsia 40:1740–9.[CrossRef][Web of Science][Medline]

McIntosh AM, Kalnins RM, Mitchell LA, Fabinyi GC, Briellmann RS, Berkovic SF. (2004) Temporal lobectomy: long-term seizure outcome, late recurrence and risks for seizure recurrence. Brain 127:2018–30.[Abstract/Free Full Text]

Newcombe RG and Altman DG. (2003) Proportions and their differences. In Altman DG, Machin D, Bryant TN, Gardner MJ (Eds.). Statistics with confidence(British Medical Journal Books, London) pp. 45–56.

Nilsson L, Ahlbom A, Farahmand BY, Tomson T. (2003) Mortality in a population-based cohort of epilepsy surgery patients. Epilepsia 44:575–581.[CrossRef][Web of Science][Medline]

Ojemann GA and Dodrill CB. (1985) Verbal memory deficits after left temporal lobectomy for epilepsy. Mechanism and intraoperative prediction. J Neurosurg 62:101–7.[Web of Science][Medline]

Paglioli E, Palmini A, Paglioli E, da Costa JC, Portuguez M, Martinez JV, et al. (2004) Survival analysis of the surgical outcome of temporal lobe epilepsy due to hippocampal sclerosis. Epilepsia 45:1383–91.[CrossRef][Web of Science][Medline]

Penfield W and Paine K. (1955) Health outcomes in persons with epilepsy. Can Med J 73:515–30.[Medline]

Pulsifer MB, Brandt J, Salorio CF, Vining EP, Carson BS, Freeman JM. (2004) The cognitive outcome of hemispherectomy in 71 children. Epilepsia 45:243–54.[CrossRef][Web of Science][Medline]

Reid K, Herbert A, Baker GA. (2004) Epilepsy surgery: patient-perceived long-term costs and benefits. Epilepsy Behav 5:81–7.[Web of Science][Medline]

Rodin E, Rennick P, Dennerll R, Lin Y. (1972) Vocational and educational problems of epileptic patients. Epilepsia 13:149–60.[Web of Science][Medline]

Rossetti AO, Dworetzky BA, Madsen JR, Golub O, Beckman JA, Bromfield EB. (2005) Ictal asystole with convulsive syncope mimicking secondary generalisation: a depth electrode study. J Neurol Neurosurg Psychiatry 76:885–7.[Abstract/Free Full Text]

Ryvlin P and Kahane P. (2003) Does epilepsy surgery lower the mortality of drug-resistant epilepsy? Epilepsy Res 56:105–20.[CrossRef][Web of Science][Medline]

Ryvlin P, Montavont A, Kahane P. (2005) The impact of epilepsy surgery on mortality. Epileptic Disord 7:Suppl 1, 39–46.[Medline]

Sakas DE and Phillips J. (1996) Anterior callosotomy in the management of intractable epileptic seizures: significance of the extent of resection. Acta Neurochir (Wien) 138:700–7.[CrossRef][Medline]

Salanova V, Markand O, Worth R. (1999) Longitudinal follow-up in 145 patients with medically refractory temporal lobe epilepsy treated surgically between 1984 and 1995. Epilepsia 40:1417–23.[CrossRef][Web of Science][Medline]

Salanova V, Markand O, Worth R. (2002) Temporal lobe epilepsy surgery: outcome and complications and late mortality rate in 215 patients. Epilepsia 43:170–4.[CrossRef][Web of Science][Medline]

Schmidt D and Loscher W. (2003) How effective is surgery to cure seizures in drug-resistant temporal lobe epilepsy? Epilepsy Res 56:85–91.[CrossRef][Web of Science][Medline]

Schmidt D, Baumgartner C, Loscher W. (2004) The chance of cure following surgery for drug-resistant temporal lobe epilepsy. What do we know and do we need to revise our expectations? Epilepsy Res 60:187–201.[Web of Science][Medline]

Sirven JI, Malamut BL, O'Connor MJ, Sperling MR. (2000) Temporal lobectomy outcome in older versus younger adults. Neurology 54:2166–70.[Abstract/Free Full Text]

Spencer SS. (1996) Long-term outcome after epilepsy surgery. Epilepsia 37:807–13.[CrossRef][Web of Science][Medline]

Sperling MR, Saykin AJ, Roberts FD, French JA, O'Connor MJ. (1995) Occupational outcome after temporal lobectomy for refractory epilepsy. Neurology 45:970–7.[Abstract/Free Full Text]

Sperling MR, Feldman H, Kinman J, Liporace JD, O'Connor MJ. (1999) Seizure control and mortality in epilepsy. Ann Neurol 46:45–50.[CrossRef][Web of Science][Medline]

Sperling MR, Harris A, Nei M, Liporace JD, O'Connor MJ. (2005) Mortality after epilepsy surgery. Epilepsia 46:Suppl 11, 49–53.

Stavem K and Guldvog B. (2005) Long-term survival after epilepsy surgery compared with matched epilepsy controls and the general population. Epilepsy Res 63:67–75.[CrossRef][Web of Science][Medline]

Tellez-Zenteno JF, Dhar R, Wiebe S. (2005a) Long-term seizure outcomes following epilepsy surgery: a systematic review and meta-analysis. Brain 128:1188–98.[Abstract/Free Full Text]

Tellez-Zenteno JF, Matijevic S, Wiebe S. (2005b) Somatic comorbidity of epilepsy in the general population in Canada. Epilepsia 46:1955–62.[CrossRef][Web of Science][Medline]

Tellez-Zenteno JF, Ronquillo LH, Wiebe S. (2005c) Sudden unexpected death in epilepsy: evidence-based analysis of incidence and risk factors. Epilepsy Res 65:101–15.[CrossRef][Web of Science][Medline]

Tomson T, Beghi E, Sundqvist A, Johannessen SI. (2004) Medical risks in epilepsy: a review with focus on physical injuries, mortality, traffic accidents and their prevention. Epilepsy Res 60:1–16.[CrossRef][Web of Science][Medline]

Vickrey BG, Hays RD, Rausch R, Engel J Jr, Visscher BR, Ary CM, et al. (1995) Outcomes in 248 patients who had diagnostic evaluations for epilepsy surgery. Lancet 346:1445–9.[CrossRef][Web of Science][Medline]

Wass CT, Rajala MM, Hughes JM, Sharbrough FW, Offord KP, Rademacher DM, et al. (1996) Long-term follow-up of patients treated surgically for medically intractable epilepsy: results in 291 patients treated at Mayo Clinic Rochester between July 1972 and March 1985. Mayo Clin Proc 71:1105–13.[Abstract]

Wiebe S. (2006) Outcome measures in intractable epilepsy. Adv Neurol 97:11–5.[Medline]

Wiebe S, Blume WT, Girvin JP, Eliasziw M. (2001) A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med 345:311–8.[Abstract/Free Full Text]

Wieser HG and Hane A. (2003) Antiepileptic drug treatment before and after selective amygdalohippocampectomy. Epilepsy Res 55:211–23.[CrossRef][Web of Science][Medline]


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