Seizure Recurrence after Planned Discontinuation of Antiepileptic Drugs in Seizure-free Patients after Epilepsy Surgery: A Review of Current Clinical Experience

Long-term seizure, cognitive, and psychiatric outcome following trans-middle temporal gyrus amygdalohippocampectomy and standard temporal lobectomy

OBJECT

Previous comparisons of standard temporal lobectomy (STL) and selective amygdalohippocampectomy (SelAH) have been limited by inadequate long-term follow-up, variable definitions of favorable outcome, and inadequate consideration of psychiatric comorbidities.

METHODS

The authors performed a retrospective analysis of seizure, cognitive, and psychiatric outcomes in a noncontemporaneous cohort of 69 patients with unilateral refractory temporal lobe epilepsy and MRI evidence of mesial temporal sclerosis after either an STL or an SelAH and examined seizure, cognitive, and psychiatric outcomes.

RESULTS

The mean duration of follow-up for STL was 9.7 years (range 1-18 years), and for trans-middle temporal gyrus SelAH (mtg-SelAH) it was 6.85 years (range 1-15 years). There was no significant difference in seizure outcome when "favorable" was defined as time to loss of Engel Class I or II status; better seizure outcome was seen in the STL group when "favorable" was defined as time to loss of Engel Class IA status (p=0.034). Further analysis revealed a higher occurrence of seizures solely during attempted medication withdrawal in the mtg-SelAH group than in the STL group (p=0.016). The authors found no significant difference in the effect of surgery type on any cognitive and most psychiatric variables. Standard temporal lobectomy was associated with significantly higher scores on assessment of postsurgical paranoia (p=0.048).

CONCLUSIONS

Overall, few differences in seizure, cognitive, and psychiatric outcome were found between STL and mtg-SelAH on long-term follow-up. Longer exposure to medication side effects after mtg-SelAH may adversely affect quality of life but is unlikely to cause additional functional impairment. In patients with high levels of presurgical psychiatric disease, mtg-SelAH may be the preferred surgery type.

Evaluation of different antiepileptic drug strategies in medically refractory epilepsy patients following epilepsy surgery

PURPOSE

This study aimed to explore the most appropriate antiepileptic drug strategies after successful epilepsy surgery.

METHODS

A total of 131 refractory epilepsy patients who underwent epilepsy surgery from January 2005 to December 2008 in the Department of Neurosurgery, West China Hospital, were retrospectively reviewed. Patients were divided into three groups (monotherapy, duotherapy, and polytherapy) according to drug combinations used immediately after epilepsy surgery. Seizure outcomes were followed up for more than 2 years. Engel classification was used to evaluate seizure outcomes.

RESULTS

The mean postoperative follow-up period was 3.7±1.0 years. Preoperative baseline data among the three groups were comparable. Seizure recurrence rate in monotherapy was obviously higher than in other groups (34.1% vs. 15.1%, 7.1%) at 6-month follow-up, which showed a statistically significant difference (p=0.02). Seizure outcomes for 2 years were assessed using Engel classification. In the duotherapy group, the rate of Engel class I was definitely higher than in the other two groups (69.9% vs. 47.7%, 57.1%, p=0.02). Seizure relapse rates at the 2-year follow-up, after planned reduction or withdrawal, were 46.4% for monotherapy, 16.9% for duotherapy, and 25.0% for polytherapy (p=0.01).

CONCLUSIONS

Monotherapy may be not sufficient enough to control seizures completely. It appears to have a higher risk for seizure relapse when considering drug reduction. It suggests that duotherapy may be more effective and safer than monotherapy. Even after successful epilepsy surgery, duotherapy seems preferable to monotherapy or polytherapy for control of residual seizures.

Epilepsy. Outcome patterns in epilepsy surgery--the long-term view

Predicting response to therapy in individual patients with epilepsy is not straightforward. An exploration of long-term surgical outcomes in an epilepsy cohort has identified seven patterns of remission and relapse, and the probability of each outcome has been calculated. The study provides new predictors of postoperative outcomes in epilepsy.

Mesial temporal lobe epilepsy: How do we improve surgical outcome?

Surgery has become the standard of care for patients with intractable temporal lobe epilepsy, with anterior temporal lobe resection the most common operation performed for adults with hippocampal sclerosis. This procedure leads to significant improvement in the lives of the overwhelming majority of patients. Despite improved techniques in neuroimaging that have facilitated the identification of potential surgical candidates, the short-term and long-term success of epilepsy surgery has not changed substantially in recent decades. The basic surgical goal, removal of the amygdala, hippocampus, and parahippocampal gyrus, is based on the hypothesis that these structures represent a uniform and contiguous source of seizures in the mesial temporal lobe epilepsy (MTLE) syndrome. Recent observations from the histopathology of resected tissue, preoperative neuroimaging, and the basic science laboratory suggest that the syndrome is not always a uniform entity. Despite clinical similarity, not all patients become seizure-free. Improving surgical outcomes requires a re-examination of why patients fail surgery. This review examines recent findings from the clinic and laboratory. Historically, we have considered MTLE a single disorder, but it may be time to view it as a group of closely related syndromes with variable type and extent of histopathology. That recognition may lead to identifying the appropriate subgroups that will require different diagnostic and surgical approaches to improve surgical outcomes.

Postoperative interictal epileptiform discharge within 1 month is associated with seizure recurrence after anterior temporal lobectomy

To investigate the relationship of interictal epileptiform discharges (IEDs) within 1 month of anterior temporal lobectomy (ATL) to seizure outcome, we reviewed data for 202 (107 left ATL, 95 right ATL) patients who had undergone ATL for mesial temporal epilepsy. Postoperative EEGs within 30 days and other preoperative variables were analyzed to examine the significant factors that determine freedom from disabling seizures. IEDs were noted in 29 (22.3%) of the 130 patients without seizures for 2 years after ATL compared with 31 (43.1%) of the 72 patients with recurrent seizures (P = 0.002). Postoperative IEDs remained an independent predictive factor for seizure outcome by logistic regression (adjusted OR = 2.38, 95% CI = 1.18-4.81, P = 0.016, 2 years postoperatively; adjusted OR = 2.22, 95% CI = 1.03-4.82, P = 0.043, 5 years postoperatively) and Cox hazard regression analysis (adjusted HR = 1.76, 95% CI = 1.18-2.62, P = 0.006) after controlling for other predicting factors (unilateral hippocampal atrophy, history of febrile seizures, and IQ scores). In this study, IEDs on the EEG obtained soon after surgery were associated with postoperative seizure recurrence. These results can be used in the assessment of risk of seizure recurrence after ATL.

Longitudinal analyses of the surgical outcomes of pediatric epilepsy patients with focal cortical dysplasia

OBJECT

The long-term surgical outcome of pediatric patients with epilepsy accompanied by focal cortical dysplasia (FCD) is not clear. The authors report on the long-term surgical outcomes of children with FCD, based on longitudinal analyses.

METHODS

The authors retrospectively analyzed the records of 41 children who underwent epilepsy surgery for pathologically proven FCD. Twenty of these patients were male and 21 were female. The median age at surgery was 9 years (range 1-17 years).

RESULTS

The actuarial seizure-free rates were 49, 44, and 33% in the 1st, 2nd, and 5th years after surgery, respectively. There was no seizure recurrence after 3 years. Three patients with initial failure of seizure control experienced late remission of seizures (the so-called running-down phenomenon). Eventually, 19 patients (46%) were seizure free at their last follow-up visit. Absence of a lesion on MR imaging and incomplete resection were significantly associated with seizure-control failure. Concordance of presurgical evaluation data was a marginally significant variable for seizure control in patients with lesional epilepsy. Three patients with seizure-control failure became seizure free as a result of the running-down phenomenon. The actuarial rate of antiepileptic drug discontinuation was 91% in the 5th year in the seizure-free patients.

CONCLUSIONS

The seizure-free rate after surgery in children with FCD was 49% in the 1st year; however, it declined thereafter. The running-down phenomenon could be an important mechanism of seizure alleviation for patients with FCD during long-term follow-up. Because a complete resection of FCD has a strong prognostic implication for seizure control, a better method to define the extent of FCD is required to assist with resection, especially in nonlesional epilepsy.

Successful surgical treatment of medically refractory epilepsy after chemotherapy in a child with leukemia: a case report

INTRODUCTION

Mesial temporal sclerosis associated with acute lymphoblastic leukemia has been rarely reported.

CASE REPORT

We report a case of a 15-year-old boy with acute lymphoblastic leukemia who developed medically refractory temporal lobe epilepsy in a long time period after chemotherapy, and successfully treated with surgical resection.

CONCLUSIONS

To our knowledge, this is the first description of a leukemic child with medically refractory temporal lobe epilepsy who achieved seizure-freedom postoperatively during the long-term follow-up. The clinical history and details of the underlying pathophysiological background and treatment of this complication are discussed in this case report.

Management of the patient with medically refractory epilepsy

Epilepsy imposes a significant clinical, epidemiologic and economic burden on societies throughout the world. Despite the development of more than ten new antiepileptic drugs over the past 15 years, approximately a third of patients with epilepsy remain resistant to pharmacotherapy. Individuals who fail to respond, or respond only partially, continue to have incapacitating seizures. Managing patients with medically refractory epilepsy is challenging and requires a structured multidisciplinary approach in specialized clinics. If the problems related to drug resistance could be resolved, even in part, by improving the pharmacokinetic profile of existing drugs, the economic savings would be remarkable and the time required to design drugs that achieve seizure control would be shorter than the discovery of new targets and molecules was required. A promising approach is the use of corticosteroids that may have a dual beneficial effect. Resective brain surgery remains the ultimate and highly successful approach to multiple drug resistance in epileptic patients.

Medication policy after epilepsy surgery

The postsurgical medication policy was reviewed for 109 children (age at surgery, 0-16 years) who had epilepsy surgery between 1991 and 2005. Intervals between surgery and both start (n = 84) and completion (n = 68) of withdrawal of antiepileptic drugs (AEDs) were calculated and analyzed in relation to demographic and epilepsy variables and to recurrent seizures. Postoperative seizure freedom was associated with completeness of surgical resection, defined as complete removal of the cortical region exhibiting ictal or interictal abnormalities on intracranial electroencephalography and lesion on magnetic resonance imaging (P = 0.008). Etiology seemed to be related, but numbers were too small for statistical analysis. In 24 children (22%), seizures recurred postoperatively, and in 19 of these 24 children the AEDs were never withdrawn. Two of the five children in whom seizures recurred after medication withdrawal regained seizure freedom. Mean interval from surgery to start of drug withdrawal was 1.71 years (n = 84), and 2.86 years (n = 68) from surgery to complete withdrawal. Seizure recurrence seemed not associated with withdrawal decisions. Timing of seizure relapse was identical in children still on AEDs and in those who stopped. Eight children with early discontinuation (0.6 years from surgery to start of withdrawal and 0.8 years to complete withdrawal) had no seizure recurrence. Long-term continuation of AEDs is probably not indicated in children with complete resection of the epileptogenic zone. The optimal timing needs to be further explored.

Drug withdrawal after successful epilepsy surgery: how safe is it?

Discontinuation of antiepileptic drugs (AEDs) is one reason patients undergo epilepsy surgery, but little is known about the risk of seizure recurrence. We describe a prospective pilot study of withdrawal performed at our epilepsy center. Sixty completely seizure-free patients were included between 1997 and 2003. AED withdrawal was proposed 1 year after surgery after a detailed discussion of the risks and benefits. On the basis of their decision on withdrawal, patients were stratified into two cohorts (withdrawal group, N=34; control group, N=26). Discontinuation was carried out in small tapering steps over 1 year with yearly follow-up visits. Withdrawal was stopped when seizures recurred or the patients objected to further discontinuation. Twenty-six of 34 (76.5%) persons in the withdrawal group and 16 of 26 (61.5%) persons in the control group were seizure free 5 years after surgery. In this study, AED discontinuation 1 year after successful epilepsy surgery was not associated with a risk of seizure recurrence higher than that of controls.

Prognosis after late relapse following epilepsy surgery

OBJECTIVES

To assess prognosis after late relapse in patients who are seizure free for the first 5 years after epilepsy surgery.

METHODS

Patients who were seizure free for the first 5 years after resective epilepsy surgery were included. Date of first seizure recurrence, current seizure status, medication, age, and type of surgery were prospectively registered. Non-parametric statistics were used.

RESULTS

One hundred and fifty-nine patients were studied. Thirty-two had at least one recurrent seizure. Time to event analysis showed an annual relapse rate of 4% between years 5 and 10 after surgery. At study termination, 143 of 159 patients (89.9%) were in terminal remission. For 30 patients with late relapse and at least 1-year follow-up thereafter, 53% were in terminal remission and 30% had experienced only rare or nocturnal seizures. Medication use was not associated either with likelihood of relapse or entering remission after relapse.

CONCLUSIONS

Patients who are seizure free for the first 5 years after epilepsy surgery remain at risk for seizure recurrence. These relapses are often isolated events, and the long-term prognosis after relapse is often good. Relapse rates were similar in patients on and off AEDs, but the relation between AED taper and relapse is uncertain since patient groups may not be similar.

Discontinuation of medications after successful epilepsy surgery in children

To evaluate the need for antiepileptic drugs after successful epilepsy surgery in pediatric patients, we retrospectively reviewed patients who had epilepsy surgery and were seizure free or had rare nondisabling auras during the first 6 postoperative months. Association between drug discontinuation and seizure recurrence was evaluated using Cox proportional hazards multivariable survival analysis. Medications were withdrawn in 68 of 97 patients, seizure free (or with rare nondisabling auras) for >6 months after surgery; 57 of the 68 (84%) remained seizure free; the other 11 (16%) had seizure recurrence after 68 months (median). Seizure recurrence was controlled with medication in 7 of the 11 patients (3 have rare seizures, 1 frequent auras). Discontinuing medications at <6 mo, compared with later or no withdrawal, had significant risk for seizure recurrence (hazard ratio 5.8; 95% confidence interval 1.8, 17.5; P = 0.003). Of 29 patients who continued drugs, 28 (97%) remained seizure free after 37 months (median). Freedom from seizures 6 months after surgery predicted good outcome (95% seizure free, with or without medication). If discontinuation is offered after 6 months, the majority of patients (84%) can be expected to remain seizure free with no further need for medication. Although seizure breakthrough is possible in a smaller percentage, restarting drugs is likely to restore seizure control.

Modern management of epilepsy: a practical approach

The epilepsies are among the most common serious brain disorders, can occur at all ages, and are characterized by a variety of presentations and causes. Diagnosis of epilepsy remains clinical, and neurophysiological investigations support the diagnosis of the syndrome. Brain imaging is able to identify many of the structural causes of the epilepsies. Current antiepileptic drugs (AEDs) block seizures without influencing the underlying tendency to generate seizures, and are effective in 60-70% of individuals. Several modern drugs are as efficacious as the older medications, but have important advantages including the absence of adverse drug interactions and hypersensitivity reactions. Epilepsy is associated with an increased prevalence of mental health disorders including anxiety, depression, and suicidal thoughts. An understanding of the psychiatric correlates of epilepsy is important to the adequate management of people with epilepsy. Anticipation of common errors in the diagnosis and management of epilepsy is important. Frequent early diagnostic errors include nonepileptic psychogenic seizures, syncope with myoclonus, restless legs syndrome, and REM behavioral disorders, the last mostly in elderly men. Overtreatment with too rapid titration and too high doses or too many AEDs should be avoided. For people with refractory focal epilepsy, vagus nerve stimulation offers palliative treatment with possible mood improvement and neurosurgical resection offers the possibility of a life-changing cure. Potential advances in the management of epilepsy are briefly discussed. This short review summarizes the authors' how-to-do approach to the modern management of people with epilepsy.

Discontinuation of antiepileptic drugs after pediatric epilepsy surgery

In children with medically intractable seizures, epilepsy surgery is now a widely accepted option. Successful discontinuation of antiepileptic drugs after epilepsy surgery has been reported in adults, but rarely in children. Surgical outcome and need for antiepileptic drugs after temporal and extratemporal lobe resection were retrospectively reviewed for 80 pediatric patients from the Comprehensive Epilepsy Program at the University of Alberta. For 1 year after surgery, children were maintained on at least one antiepileptic drug. Antiepileptic drug discontinuation was attempted in all patients with a nonepileptic electroencephalogram after 1 year seizure-free. Less than half of the patients (44%) eventually relapsed without antiepileptic drugs. Of the 40 patients in the temporal lobe group, 13 (32%) relapsed without antiepileptic drugs, as did 22 of the 40 extratemporal lobe resection patients (55%). Success rates for antiepileptic drug discontinuation after surgery were higher in the temporal lobe than in the extratemporal lobe group. Long-term antiepileptic drugs are not necessary in all cases, and for many children medication can be withdrawn after epilepsy surgery.

Etiology and management of refractory epilepsies

The epilepsies are an important, common and diverse group of symptom complexes characterized by recurrent spontaneous seizures. Although many patients with epilepsy have their seizures controlled effectively by antiepileptic drugs (AEDs), about one-third of patients continue to have seizures, despite trying a range of AEDs. Such patients bear the heaviest burden of epilepsy, with increased morbidity and risk of premature mortality. Our current understanding of the refractory epilepsies--the most common of which are focal--is limited; even their definition is problematic. Standard treatments for refractory epilepsies include optimization of existing AED regimens, trials of further AEDs, and, for some patients, therapeutic resective neurosurgery. Recent basic research has explored possible underlying causes of refractory epilepsy, and two main hypotheses have emerged to account for the failure of AED treatment. According to one hypothesis, AEDs might fail because of alterations in the properties of their usual targets. Alternatively, they might fail because multidrug transporter mechanisms limit concentrations of the drugs at their targets. The refractory epilepsies can be viewed as offering remarkable insights into biological processes in the epilepsies, and their effective treatment remains an important aim; treatment would potentially bring much-needed relief to hundreds of thousands of patients across the world.

Long term follow-up of the first 70 operated adults in the Goteborg Epilepsy Surgery Series with respect to seizures, psychosocial outcome and use of antiepileptic drugs

OBJECTIVE

To compare long term (10 years) seizure outcome, psychosocial outcome and use of antiepileptic drugs (AED) with the 2 year follow-up in adults after resective epilepsy surgery.

METHODS

All adults (n = 70) who underwent resective epilepsy surgery from 1987 to 1995 in the Göteborg Epilepsy Surgery Series were included. Fifty-four had undergone temporal lobe resections and 16 extratemporal resections (12 frontal). A cross-sectional follow-up in the form of a semistructured interview was performed in late 2003.

RESULTS

Mean follow-up was 12.4 years (range 8.6-16.2). Of the 70 patients (51% males), five (7%) were dead (three as a result of non-epilepsy related causes). Of the 65 patients interviewed, 38 (58%) were seizure-free at the long term follow-up: 65% of the patients with temporal lobe resections and 36% of the patients with extratemporal resections. Of the 35 patients who were seizure-free at the 2 year follow-up, 3 (9%) had seizures at the long term follow-up. Of the 30 patients who had seizures at the 2 year follow-up, 6 (20%) were seizure-free at the long term follow-up. Of all 65 patients, 45 (69%) had the same seizure status as the 2 year follow-up. Sixteen (25%) had an improved seizure status and 4 (6%) had a worsened status. Of the seizure-free patients, 11 (29%) had ceased taking AED, 28 (74%) were working and 25 (66%) had a driving license.

CONCLUSIONS

Adult patients who are seizure-free 2 years after resective epilepsy surgery are most likely to still be seizure-free 10 years later. Most are working and have obtained a driving license.

Stopping antiepileptic drugs after epilepsy surgery: a survey of U.S. epilepsy center neurologists

One hundred fifty-one neurologists at U.S. epilepsy centers responded to a survey on stopping medications in patients following successful resective epilepsy surgery. Sixty-two percent said patients should be > or = 2 years seizure-free before stopping medication. Although respondents tended to agree about the importance of many of the queried factors (e.g., focal pathology in favor of and persistent auras against stopping antiepileptic drugs), it is unclear how well these factors determine seizure outcome in this setting.

Assessment of the Long-term Effects of Epilepsy Surgery with Three Different Reference Groups

PURPOSE

It is difficult to validly assess the long-term effect of epilepsy surgery. Here, this is attempted by comparing the outcome of surgically treated pharmacoresistant epilepsy patients to three different nonoperated comparison groups regarding seizure control, antiepilepsy drug (AED) usage, and health related quality of life (QOL).

METHODS

One hundred thirty-one operated patients (group 1, mean follow-up since presurgical assessment 6.9 years), 105 patients awaiting presurgical assessment (group 2, mean follow-up after assignment to waiting list 0.8 years), 99 patients considered to be presurgical candidates who chose to withdraw from waiting for presurgical assessment (group 3, mean follow-up after assignment to waiting list 5.5 years), and 49 patients who were not deemed to be eligible for surgery after comprehensive assessment (group 4, mean follow-up since presurgical assessment 6.5 years) were studied. The patients completed a questionnaire on seizures, AED usage, and QOL (ESI-55).

RESULTS

The surgical patients had a better outcome than all three comparison groups regarding seizure frequency, seizure freedom rate, and number of AEDs used. They scored higher than groups 2, 3, and 4 on 7/11, 6/11, and 3/11 ESI-55 domains, respectively.

CONCLUSIONS

The superior long-term outcome of the operated patients was most marked if compared to the patients awaiting surgery. This is compatible with the assumption that patients present for presurgical candidacy selection and assessment at a "nadir" of their disease course. After several years, a regression to the mean occurs which reduces (but does not abolish) the differences between nonoperated and operated patients.

Objective tests of symptom exaggeration in independent medical examinations

OBJECTIVE

This study used the Medical Symptom Validity Test (MSVT) to examine exaggeration of memory impairment in disability claimants.

METHODS

The MSVT was administered to patients with soft tissue injuries undergoing an independent medical examination (IME). Their results were compared with those from groups of volunteers who were either trying their best on the test or simulating memory impairment.

RESULTS

Non-French-speaking volunteers, who were tested in French, showed near perfect performance on the effort subtests, but 42% of IME patients failed the effort tests in English. Their overall results were very similar to those of simulators.

CONCLUSION

This study suggests that exaggeration of cognitive symptoms is widespread in disability-related evaluations. It would be unwise to accept self-reported memory complaints at face value. Criteria-normed symptom validity testing should be done to rule out symptom exaggeration.

Late seizures in patients initially seizure free after epilepsy surgery

PURPOSE

Surgery for medically intractable epilepsy is currently the most effective means of achieving seizure control. Although relatively few long-term outcome studies have been performed, evidence is mounting that the possibility of late seizure recurrence exists, even after an early seizure-free period. No published reports document the rate and predictors of late recurrence in a large series of patients undergoing surgery in the magnetic resonance imaging (MRI) era.

METHODS

We retrospectively queried the databases of two epilepsy surgery centers. Patients eligible for study had preoperative MRI scans, were seizure free for 1 year after surgery, and had a minimal follow-up period of 3 years. Patients with tumors or vascular lesions were excluded. We performed log-rank comparison of Kaplan-Meier product limit estimates for categoric variables and used a Cox proportional hazards model for continuous variables. Variables that were significant (p<0.05) on a univariate screen were entered into a multivariate forward step-wise Cox regression.

RESULTS

The study included 285 patients, 254 with medial temporal lobe (MTLE) and 31 with neocortical epilepsy. The probability of having a single seizure after being seizure free for 1 year was 18.3% at 5 years and 32.7% at 10 years. However, only 13% were not seizure free at the last follow-up. Predictors of late recurrences on both uni- and multivariate analysis were the presence of preoperative generalized tonic-clonic (GTC) seizures in patients with neocortical epilepsy and late age at surgery in patients with MTLE. MRI results and location of surgery were not predictive.

CONCLUSIONS

Although the risk of at least one recurrent seizure after initially successful epilepsy surgery is relatively high, the rate of recurrent intractability is low. The finding that late age at surgery and presence of preoperative GTC seizures are predictors of late recurrence indicates the importance of patient selection and early surgery for persistent seizure control.

Long-term outcome of epilepsy surgery among 399 patients with nonlesional seizure foci including mesial temporal lobe sclerosis

OBJECT

The authors reviewed the long-term outcome of focal resection in a large group of patients who had intractable partial nonlesional epilepsy, including mesial temporal lobe sclerosis (MTS), and who were treated consecutively at a single institution. The goal of this study was to evaluate the long-term efficacy of epilepsy surgery and the preoperative factors associated with seizure outcome.

METHODS

This retrospective analysis included 399 consecutive patients who underwent epilepsy surgery at Mayo Clinic in Rochester, Minnesota, between 1988 and 1996. The mean age of the patients at surgery was 32 +/- 12 years (range 3-69 years), and the mean age at seizure onset was 12 +/- 11 years (range 0-55 years). There were 214 female (54%) and 185 male (46%) patients. The mean duration of epilepsy was 20 +/- 12 years (range 1-56 years). The preceding values are given as the mean +/- standard deviation. Of the 399 patients, 237 (59%) had a history of complex partial seizures, 119 (30%) had generalized seizures, 26 (6%) had simple partial seizures, and 17 (4%) had experienced a combination of these. Preoperative evaluation included a routine and video-electroencephalography recordings, magnetic resonance imaging of the head according to the seizure protocol, neuropsychological testing, and a sodium amobarbital study. Patients with an undefined epileptogenic focus and discordant preoperative studies underwent an intracranial study. The mean duration of follow up was 6.2 +/- 4.5 years (range 0.6-15.7 years). Seizure outcome was categorized based on the modified Engel classification. Time-to-event analysis was performed using Kaplan-Meier curves and Cox regression models to evaluate the risk factors associated with outcomes. Among these patients, 372 (93%) underwent temporal and 27 (7%) had extratemporal resection of their epileptogenic focus. Histopathological examination of the resected specimens revealed MTS in 113 patients (28%), gliosis in 237 (59%), and normal findings in 49 (12%). Based on the Kaplan-Meier analysis, the probability of an Engel Class I outcome (seizure free, auras, or seizures related only to medication withdrawal) for the overall patient group was 81% (95% confidence interval [CI] 77-85%) at 6 months, 78% (CI 74-82%) at 1 year, 76% (CI 72-80%) at 2 years, 74% (CI 69-78%) at 5 years, and 72% (CI 67-77%) at 10 years postoperatively. The rate of Class I outcomes remained 72% for 73 patients with more than 10 years of follow up. If a patient was in Class I at 1 year postoperatively, the probability of seizure remission at 10 years postoperatively was 92% (95% CI 89-96%); almost all seizures occurred during the 1st year after surgery. Factors predictive of poor outcome from surgery were normal pathological findings in resected tissue (p = 0.038), male sex (p = 0.035), previous surgery (p < 0.001), and an extratemporal origin of seizures (p < 0.001).

CONCLUSIONS

The response to epilepsy surgery during the 1st follow-up year is a reliable indicator of the long-term Engel Class I postoperative outcome. This finding may have important implications for patient counseling and postoperative discontinuation of anticonvulsant medications.

Resective epilepsy surgery in childhood: the Dutch experience 1992-2002

PURPOSE

We present the outcome of resective epilepsy surgery in 69 pediatric patients who participated in the Dutch Collaborative Epilepsy Surgery Program (DCESP) between 1992 and 2002 with special emphasis on long-term follow-up.

METHODS

Sixty-nine children (aged 3 months to 17 years) operated on before 2003 were included in this study (34 temporal resections (49%), 17 extra-temporal resections (24%) and 19 hemispherectomies (27%)). Engel classification was used to assess seizure outcome annually. Cognitive outcome was assessed if possible. Two telephone surveys were carried out with an interval of 2(1/2) years to obtain data on seizure frequency, use of AEDs and on aspects op psychosocial development. Kaplan-Meier survival curves were constructed to assess recurrence of seizures after initial postsurgical seizure freedom, based on both telephone surveys.

RESULTS

Seventy percent scored Engel 1, 18% Engel 2, 6% Engel 3 and 6% Engel 4 at the time of the first telephone survey (2(1/2) years later: 77% Engel 1, 8% Engel 2, 12% Engel 3 and 3% Engel 4). Temporal resections were associated with the best seizure outcome (Engel 1 74% and 82%). AEDs could be withdrawn successfully in 53% of patients at time of the last follow-up. No negative impact on cognition was found. The first long-term follow-up (mean 4.5 years after surgery) measurement showed recurrence of seizures after initial seizure freedom in 17%. At time of the second long-term follow-up measurement (mean 7.5 years after surgery) this percentage had increased to 21%.

CONCLUSIONS

Our results support previous reports that surgery for intractable epilepsy in pediatric patients can be safely performed with satisfactory long-term results. Best results are attained in temporal resections.

Reduction of AEDs in postsurgical patients who attain remission

PURPOSE

Little evidence guides practice regarding the reduction of antiepileptic drugs (AEDs) in individuals who achieve significant periods of remission after resective surgery.

METHODS

In a prospective study of 396 individuals who underwent resective surgery for intractable seizures, the impact of reducing AEDs on relapse and predictors of relapse were examined.

RESULTS

Of 301 study subjects who attained a 1-year seizure remission after surgery, 129 reduced from two to one or from one to no AEDs after achieving remission, and 162 did not reduce drugs. Ten patients who stopped all AEDs before attaining remission were excluded from analysis. In all, 114 (39%) patients relapsed: 73 (45%) of 162 in the nonreduction group and 41 (32%) of 129 in the reduction group (p = 0.02). Patients who reduced drugs were more likely to have remitted immediately after hospital discharge (p<0.0001). After adjustment for this factor, little or no apparent impact of drug reduction on the rate of relapse was noted [rate ratio (RR), 1.1; 95% CI, 0.72-1.71; p=0.64 for reducing from two to one AED, and RR, 0.85; 95% CI, 0.50-1.45; p=0.56 for reducing from one to no AEDs]. Within the 129 patients who reduced AEDs, only delayed remission after hospital discharge was significantly associated with an increased rate of relapse (RR, 2.26; 95% CI, 1.15- 4.48; p=0.02). Continued auras had a marginally significant association with relapse (RR, 2.06; p=0.07)

CONCLUSIONS

Although many relapses in this cohort of postsurgical patients who achieved remission occurred in the context of reducing or completely eliminating AEDs, the risk was no higher than in those who continued AEDs. Randomized studies are needed to test the impact of drug reduction in seizure-free postsurgical patients.

Discontinuation of Anticonvulsant Medication after Epilepsy Surgery in Children

PURPOSE

To evaluate the long-term outcome of medication-reduction/discontinuation trials after epilepsy surgery in pediatric patients.

METHODS

Of the total Bonn pediatric surgical sample (1988-2001; n=251), we were able to obtain postsurgical follow-up data for 232 patients. We surveyed 140 of these patients by using a standardized telephone interview that addressed medication-reduction/discontinuation trials.

RESULTS

Of the 140 surveyed patients, 102 completely discontinued medication. Seven of these patients had recurring seizures that were controlled again after restarting the medication. Of 102 patients, 101 were completely seizure free during the 3 months before the survey. Postsurgical epileptic events before the trial significantly increased the risk for recurring epileptic events after the trial. Two surveyed patients lost postsurgical seizure freedom after medication reduction. We were also able to identify from the records another nine patients with complete medication discontinuation and seven patients with medication reduction. Two of these latter patients lost postsurgical seizure freedom despite restarting their medication. The total rate of patients with medication-reduction/discontinuation trials was 55%. The seizure recurrence rate in these patients was 10%. Recurring seizures could not be controlled by restarted medication in 3% of the trials. Currently, 90% of patients with discontinuation trials were seizure free without medication.

CONCLUSIONS

The reduction/withdrawal of anticonvulsant medication after successful epilepsy surgery has a low risk of seizure recurrence for pediatric patients in long-term follow-up, particularly in cases of complete postsurgical seizure freedom before the trial.

Epileptogenesis and rational therapeutic strategies

The understanding of neurobiological mechanisms of epileptogenesis is essential for rational approaches for a possible disease modification as well as treatment of underlying causes of the epilepsies. More effort is necessary to translate results from basic investigations into new approaches for clinical research and to better understand a relationship with findings from clinical studies. The following report is a condensed synapsis in which molecular mechanisms of epileptogenesis, pharmacological modulation of epileptogenesis, evidence based therapy, refractoriness and prediction of outcome is provided in order to stimulate further collaborative international research.

Overtreatment in epilepsy: how it occurs and how it can be avoided

In pharmacotherapy, overtreatment may be defined as an excessive drug load (that is, excessive drug dosages or unnecessary polypharmacy) leading to a suboptimal risk-to-benefit ratio. The risk of overtreatment in the pharmacological management of epilepsy is substantial and may have serious consequences in terms of a greater incidence and severity of adverse effects. These effects can range from subtle CNS impairment to overt toxic effects, including teratogenicity. Overtreatment also causes increased treatment costs and may even lead to a paradoxical deterioration in seizure control. The prevention and correction of overtreatment requires a thorough understanding of the situations and mechanisms that lead to inappropriate prescribing of antiepileptic drugs. These include initiating treatment in conditions where it is not indicated (for example, long-term prophylaxis after head trauma or supratentorial surgery in seizure-free patients), use of excessively fast titration rates, prescription of excessively high initial target dosages, failure to consider conditions associated with reduced dosage requirements (for example, old age or comorbidities associated with impaired drug clearance), and failure to consider the dose-response characteristics of the selected drug. Many patients whose seizures do not respond to the initially prescribed medication can be optimally managed by switching to monotherapy with an alternative agent; premature use of combination therapy represents another common form of overtreatment. Overtreatment may also result from a failure to adjust the dosage to prevent or compensate for adverse pharmacokinetic or pharmacodynamic drug interactions, and from a failure to reduce drug load in patients who have not benefited from high dosages or polypharmacy. While the measurement of drug concentrations can aid in minimising adverse effects, there is also a danger of overtreatment resulting from inappropriate interpretation of drug concentration data. Continuation of drug therapy in seizure-free patients in whom the risk-benefit ratio is in favour of gradual withdrawal may also be regarded as overtreatment. Tailoring therapy to the needs of the individual patient is the key to the successful management of epilepsy. Even though the importance of complete seizure control cannot be overemphasised, no patient should be made to suffer more from the adverse effects of treatment than from the manifestations of the seizure disorder.

Natural history of treated childhood-onset epilepsy: prospective, long-term population-based study

It is not well known how often drug resistance, a major clinical problem, occurs early or late in the course of epilepsy and how often epilepsy follows a continuous, remitting or relapsing-remitting pattern. To provide evidence if, in fact, different patterns of evolution of drug resistance and remission exist, a prospective, long-term population-based study of 144 patients followed on the average for 37.0 years (SD 7.1, median 40.0, range 11-42) since their first seizure before the age of 16 years was performed. At the end of follow-up, 67% of 144 patients were in terminal remission, on or off antiepileptic drugs. Early remission, starting within the first year of treatment, was seen in 45 patients (31%). In 23 (16%) of them, first remission continued, uninterrupted by relapse, to terminal remission. Late remission with a mean delay of 9 years was achieved by a further 72 patients (50%), including 46 (32%) patients who achieved terminal remission without any relapse and suggested, together with 23 patients, a remitting course. Following a relapse after early or late remission, 28 (19%) patients achieved terminal remission, suggesting a remitting-relapsing pattern. Altogether 20 patients (14%) did not re-enter remission, indicating a worsening course of epilepsy. Twenty-seven (19%) patients were drug-resistant from the start to the end of follow-up. In conclusion, half the patients with childhood-onset epilepsy will eventually enter terminal remission without relapse and a fifth after relapse. One-third will have a poor long-term outcome in terms of persistent seizures after remission or without any remission ever.

Seizure and memory outcome following temporal lobe surgery: selective compared with nonselective approaches for hippocampal sclerosis

Object

The aim of this study was to compare seizure and memory outcome in patients with medically refractory mesial temporal lobe epilepsy due to hippocampal sclerosis (MTLE/HS) treated using an anterior temporal lobectomy (ATL) or a selective amygdalohippocampectomy (SA).

Methods

Surgical outcome data were prospectively collected for 2 to 11 years in 161 consecutive patients with MTLE/HS. Eighty patients underwent an ATL and 81 an SA. Seizure control achieved with each technique was compared using the Engel classification scheme. Postoperative memory testing was performed in 86 patients (53%). At the last follow up, 72% of the patients who had undergone an ATL (mean follow up 6.7 years) and 71% of those who had undergone an SA (mean follow up 4.5 years) were seizure free (Engle Class IA). Estimated survival in patients in Engel Classes I, IA, and I and II combined did not differ between the two surgical techniques. Preoperatively, 58% of the patients had verbal memory scores one standard deviation (SD) below the normal mean. One third of the patients with preoperative scores in the normal range worsened after surgery, although this outcome was not related to the surgical technique. In contrast, one third of those whose preoperative scores were less than −1 SD experienced improvement after surgery. Nine (18%) of the 50 patients whose left side had been surgically treated improved their verbal memory scores by more than one SD. Seven (78%) of these nine underwent an SA (p = 0.05).

Conclusions

Both ATL and SA can lead to similar favorable seizure control in patients with MTLE/HS. Preliminary data suggest that postoperative verbal memory scores may improve in patients who undergo selective resection of a sclerotic hippocampus in the dominant temporal lobe.

Postsurgical treatment of epilepsy

In people with localization-related epilepsy who do not respond well to medication and continue to have seizures despite having been evaluated and treated by an epilepsy specialist, current recommendations are to consider surgery as an alternative to continued trials of different antiepileptic drugs (AEDs).

Uncontrolled epilepsy following discontinuation of antiepileptic drugs in seizure-free patients: a review of current clinical experience

PURPOSE

We reviewed the impact of planned discontinuation of antiepileptic drugs (AEDs) in seizure-free patients on seizure recurrence and the seizure outcome of reinstituted treatment.

METHODS

A literature review was performed yielding 14 clinical observations of seizure recurrence after discontinuation and its treatment outcome.

RESULTS

Seizure recurrence rate after AED discontinuation ranged between 12 and 66% (mean 34%, 95%CI: 27-43) in the 13 reviewed studies (no data in one study). Reinstitution of AEDs after recurrence was efficacious between 64-91% (mean of 14 studies, 80%, 95%CI: 75-85%) at follow-up. Mean follow-up ranged from 1-9 years. Seizure outcome of resumed treatment was not different for series in children and adolescents (84%, mean of 4 studies, 95%CI: 75-93) or in adults only (80%, mean of 9 studies, 95%CI: 74-86). Although seizure control was regained within approximately one year in half of the cases becoming seizure free, it took some patients as many as 5-12 years. In addition, in 19% (mean of 14 studies, 95%CI: 15-24%), resuming medication did not control the epilepsy as before, and chronic drug-resistant epilepsy with many seizures over as many as five years was seen in up to 23% of patients with a recurrence. Factors associated with poor treatment outcome of treating recurrences were symptomatic etiology, partial epilepsy and cognitive deficits.

CONCLUSIONS

These serious and substantial risks weigh against discontinuation of AEDs in seizure-free patients, except perhaps for selected patients with idiopathic epilepsy syndromes of childhood or patients with rare seizures.

Long-term seizure outcomes following epilepsy surgery: a systematic review and meta-analysis

Assessment of long-term outcomes is essential in brain surgery for epilepsy, which is an irreversible intervention for a chronic condition. Excellent short-term results of resective epilepsy surgery have been established, but less is known about long-term outcomes. We performed a systematic review and meta-analysis of the evidence on this topic. To provide evidence-based estimates of long-term results of various types of epilepsy surgery and to identify sources of variation in results of published studies, we searched Medline, Index Medicus, the Cochrane database, bibliographies of reviews, original articles and book chapters to identify articles published since 1991 that contained > or =20 patients of any age, undergoing resective or non-resective epilepsy surgery, and followed for a mean/median of > or =5 years. Two reviewers independently assessed study eligibility and extracted data, resolving disagreements through discussion. Seventy-six articles fulfilled our eligibility criteria, of which 71 reported on resective surgery (93%) and five (7%) on non-resective surgery. There were no randomized trials and only six studies had a control group. Some articles contributed more than one study, yielding 83 studies of which 78 dealt with resective surgery and five with non-resective surgery. Forty studies (51%) of resective surgery referred to temporal lobe surgery, 25 (32%) to grouped temporal and extratemporal surgery, seven (9%) to frontal surgery, two (3%) to grouped extratemporal surgery, two (3%) to hemispherectomy, and one (1%) each to parietal and occipital surgery. In the non-resective category, three studies reported outcomes after callosotomy and two after multiple subpial transections. The median proportion of long-term seizure-free patients was 66% with temporal lobe resections, 46% with occipital and parietal resections, and 27% with frontal lobe resections. In the long term, only 35% of patients with callosotomy were free of most disabling seizures, and 16% with multiple subpial transections remained free of all seizures. The year of operation, duration of follow-up and outcome classification system were most strongly associated with outcomes. Almost all long-term outcome studies describe patient cohorts without controls. Although there is substantial variation in outcome definition and methodology among the studies, consistent patterns of results emerge for various surgical interventions after adjusting for sources of heterogeneity. The long-term (> or =5 years) seizure free rate following temporal lobe resective surgery was similar to that reported in short-term controlled studies. On the other hand, long-term seizure freedom was consistently lower after extratemporal surgery and palliative procedures.

Failed surgery for temporal lobe epilepsy: Predictors of long-term seizure-free course

OBJECTIVES

To identify prognostic factors which predict the outcome 2 years after TLE surgery in those patients who were not seizure-free at the 6-month postoperative examination.

METHODS

We included 86 postoperative TLE patients who had undergone presurgical evaluation, including video-EEG and high-resolution MRI, and who had seizures between the second and sixth postoperative months.

RESULTS

32% of patients were seizure-free in the second postoperative year. We found that normal MRI findings and secondarily generalized seizures (SGTCS) preoperatively were associated with a non-seizure-free outcome, while rare postoperative seizures and ipsilateral temporal IED with seizure-free outcome. Newly administered levetiracetam showed a significant positive effect on the postoperative outcome independent of other prognostic factors. Five of seven patients who received levetiracetam became seizure-free (p = 0.006).

CONCLUSION

One-third of patients who did not become seizure-free immediately after surgery, eventually achieved long-term seizure freedom. We suggest watching for long-term seizure freedom after failed epilepsy surgery especially in patients who had rare postoperative seizures, focal MRI abnormality, ipsilateral temporal spikes, or no SGTCS preoperatively. Levetiracetam may have a positive effect on postsurgical seizures.

Antiepileptic Drug Withdrawal after Successful Surgery for Intractable Temporal Lobe Epilepsy

PURPOSE

To investigate the prognosis related to antiepileptic drug (AED) discontinuation after successful surgery for intractable temporal lobe epilepsy.

METHODS

The clinical courses after temporal lobectomies (TLs) were retrospectively analyzed in 88 consecutive patients. All the patients had TLs as the only surgical procedure, and they had been followed up for longer than 3 years. AED discontinuation was attempted if the patient had been seizure free without aura for >or=1 year during the follow-up period.

RESULTS

Sixty-six (75%) patients achieved complete seizure freedom for >or=1 year; 28 patients were seizure free immediately after surgery (immediate success); and 38 patients became seizure free after some period of recurrent seizures (delayed success). AED discontinuation was attempted in 60 (91%) of 66 patients with a successful outcome. In 13 (22%) patients, seizure relapse developed during AED reduction (n=60), and in seven (12%) patients after discontinuation of AEDs (n=38). The seizure recurrence rate was not different between the immediate-and delayed-success groups. Among 20 patients with seizure relapse related to AED tapering, nine (45%) of them regained seizure freedom after reinstitution of AED treatment, and AEDs were eventually discontinued in six of them. Seizures that recurred after complete AED discontinuation had a better prognosis than did the seizures that recurred during AED reduction (seizure freedom in 86% vs. 23%). At the final assessment, 54 (61%) patients had been seizure free >or=1 year; 37 without AEDs and 17 with AEDs. The successful discontinuation of AEDs was more frequent for patients with a younger age at the time of surgery and for those patients with shorter disease duration.

CONCLUSIONS

Our results suggest that seizure freedom without aura at >or=1 year is a reasonable indication for the attempt at AED discontinuation. The subsequent control of recurrent seizures was excellent, especially if seizures relapsed after the complete discontinuation of AEDs. Younger age at the time of surgery and a shorter disease duration seem to affect successful AED discontinuation for a long-term period.

The chance of cure following surgery for drug-resistant temporal lobe epilepsy. What do we know and do we need to revise our expectations?

Although surgery is often seen as a curative treatment for patients with drug-resistant temporal lobe epilepsy, little information is available how many cases can be considered cured after surgery, i.e. are seizure-free for several years without taking antiepileptic drugs (AEDs). In our review, 13 retrospective and five prospective clinical observations published since 1980 provided data on long-term seizure control off AEDs in a total of 1658 patients. No randomized studies were found. Following temporal lobe surgery, approximately one in four adult patients and approximately one in three children or adolescents can currently shown to be seizure-free for 5 years without AEDs (25%, mean of eight studies in adults, 95% CI: 21-30%, and 31%, mean of three studies in children, 95% CI: 20-41%). The rate of seizure control off AEDs seemed to be stable after 2 years of follow-up. However, as 55% of patients free of disabling seizures preferred not to discontinue their medication completely as late as 5 years after surgery, it is impossible to know if they are cured or not. No features predictive of surgical cure were detected except for better cure outcome in children versus adults with hippocampal sclerosis and in patients with typical versus atypical Ammonshorn's sclerosis or tumor in one small study each. In conclusion, the available evidence on seizure outcome off AEDs after temporal lobe surgery is based on non-randomized studies and, in part, data were collected retrospectively. A randomized controlled trial is needed to determine if, in fact only one in three to four patients with temporal lobe epilepsy undergoing surgery can be considered cured.