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

Predictors of longitudinal seizure outcomes after epilepsy surgery in childhood

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Long term seizure outcome in children following epilepsy surgery is favorable.

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Histopathology is an independent determinant of long-term seizure outcome.

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Long-term seizure outcome remains stable in children with tumours and FCD type 2b, whereas seizure freedom declines with time in children with other types of FCD and cortical malformations.

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Children with moderate to severe developmental disability and younger age of seizure onset have higher seizure recurrence reflecting broader epileptic networks.

There is a paucity of data on longitudinal seizure outcome of children undergoing epilepsy surgery. All children (n = 132) who underwent resective epilepsy surgery from January 1998 to December 2015 were identified. Relevant clinical, neurophysiological, imaging, surgical and seizure outcome data were extracted. Multivariable logistic regression analysis and Kaplan-Meier survival with Cox proportional hazard modelling were performed. The mean age at surgery was 7.8 years (range 0.2–17.9). 71% were seizure-free at a mean follow up of 5.3 ± 2.7 years. Of those who were seizure-free, 65 patients were able to completely wean off anti- seizure medications successfully. Using survival analysis, the probability of Engel Class I outcome at one year after surgery was 81% (95% confidence interval [CI] 87%–75%). This dropped to 73% at two years (95% CI 81%–65%), 58% at five years (95% CI 67.8%–48%), and 47% at ten years. Proportional hazard modelling showed that the presence of moderate to severe developmental disability (HR 6.5; p = 0.02) and lack of complete resection (HR 0.4; p = 0.02) maintain association as negative predictors of seizure-free outcome. Our study demonstrates favorable long-term seizure control following pediatric epilepsy surgery and highlights important predictors of seizure outcome guiding case selection and counseling of expectations prior to surgery.

Surgery for Intractable Epilepsy in Pediatrics, a Systematic Review of Outcomes other than Seizure Freedom

To perform a systematic review evaluating reported outcomes for epilepsy surgery in pediatric patients with pharmacoresistant epilepsy beyond seizure control, including impact on quality of life, behavioral, neurocognitive outcomes as well as complications, and death. We reviewed articles from both EMBASE and MEDLINE/PubMed articles that met formal criteria (patients ≤18 years, those with intractable epilepsy, at least 5 patients in the case series, published in peer-reviewed journal). Each reviewer independently reviewed the articles and those with discrepancies were discussed and consensus was reached. Out of a total of 536 abstracts obtained from EMBASE and MEDLINE/PubMed searches combined with additional cross-referencing, a total of 98 manuscripts ultimately met all inclusion criteria. The manuscripts were divided into 3 outcomes categories: Quality of Life (16), Cognitive Outcomes (60), and Deficits and Complications (50). Several papers fell into more than 1 category. These were separated by surgical types and evaluated. We found that overall reporting in all domains was variable and inconsistent amongst the different studies. This systematic review highlights the lack of completeness in reporting outcomes and complications involving pediatric epilepsy surgery and discordant results. This underscores the importance of multicenter systematic prospective data collection in pediatric patients who undergo pediatric epilepsy surgery.

The Putative Role of mTOR Inhibitors in Non-tuberous Sclerosis Complex-Related Epilepsy

Epilepsy affects ~5 out of every 10,000 children per year. Up to one-third of these children have medically refractory epilepsy, with limited to no options for improved seizure control. mTOR, a ubiquitous 289 kDa serine/threonine kinase in the phosphatidylinositol 3-kinase (PI3K)-related kinases (PIKK) family, is dysregulated in a number of human diseases, including tuberous sclerosis complex (TSC) and epilepsy. In cell models of epilepsy and TSC, rapamycin, an mTOR inhibitor, has been shown to decrease seizure frequency and duration, and positively affect cell growth and morphology. Rapamycin has also been shown to prevent or improve epilepsy and prolong survival in animal models of TSC. To date, clinical studies looking at the effects of mTOR inhibitors on the reduction of seizures have mainly focused on patients with TSC. Everolimus (Novartis Pharmaceuticals), a chemically modified rapamycin derivative, has been shown to reduce seizure frequency with reasonable safety and tolerability. Mutations in mTOR or the mTOR pathway have been found in hemimegalencephaly (HME) and focal cortical dysplasias (FCDs), both of which are highly correlated with medically refractory epilepsy. Given the evidence to date, a logical next step is to investigate the role of mTOR inhibitors in the treatment of children with medically refractory non-TSC epilepsy, particularly those children who have also failed resective surgery.

Increase in cognitive function is seen in many single-operated pediatric patients after epilepsy surgery

PURPOSE

The recurrent seizures of pediatric drug-resistant epilepsy (DRE) are known to impair brain development and can lead to a loss in cognitive functioning. Surgery is increasingly being used to treat children with DRE. This study investigates the pre- and postoperative cognitive function in a pediatric epilepsy surgery cohort as well as predictive determinants of change in intelligence quotient (IQ) following surgery.

METHODS

A consecutive series of 91 Danish children who underwent focal resective epilepsy surgery between January 1996 and December 2016 were included. All underwent preoperative cognitive evaluation and were reevaluated at 1-year and/or 2-year follow-up. Single-operated and multi-operated patients were examined separately.

RESULTS

79 of 91 patients were single-operated. Single-operated patients received less anti-epileptic drugs (AED) and experienced a decrease in seizure frequency postoperatively, p < 0.001. IQ increased postoperatively (IQ change ± standard deviation: 3.3 ± 14.0), p < 0.05. High preoperative seizure frequency was a significant predictor for decreased IQ, p < 0.01. Multi-operated patients did not experience a reduction in AED treatment. Surgery and continued AED treatment did, however, result in significantly better seizure control, p < 0.01. IQ remained unchanged in multi-operated patients.

CONCLUSION

Epilepsy surgery allowed for IQ gains in single-operated patients. Preoperative seizure frequency was a significant predictor of IQ change following surgery. Interactions between other, not included, possible predictors remain to be examined. Single-operated patients had the best cognitive outcome. The inclusion of a non-surgical control group is needed to assess the extent of the beneficial effects of surgery on cognitive ability.

An Initial Cost-Effectiveness Analysis of Magnetic Resonance-Guided Laser Interstitial Thermal Therapy in Pediatric Epilepsy Surgery

INTRODUCTION

Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a new technology that provides a clinically efficacious and minimally invasive alternative to conventional microsurgical resection. However, little data exist on how costs compare to traditional open surgery. The goal of this paper is to investigate the cost-effectiveness of MRgLITT in the treatment of pediatric epilepsy.

METHODS

We retrospectively analyzed the medical records of pediatric patients who underwent MRgLITT via the Visualase® thermal therapy system (Medtronic, Inc., Minneapolis, MN, USA) between December 2013 and September 2017. Direct costs associated with preoperative, operative, and follow-up care were extracted. Benefit was calculated in quality-adjusted life years (QALYs), and the cost-effectiveness was derived from the discounted total direct costs over QALY. Sensitivity analysis on 4 variables was utilized to assess the validity of our results.

RESULTS

Twelve consecutive pediatric patients with medically refractory epilepsy underwent MRgLITT procedures. At the last postoperative follow-up, 8 patients were seizure free (Engel I, 66.7%), 2 demonstrated significant improvement (Engel II, 16.7%), and 2 patients showed worthwhile improvement (Engel III, 16.7%). The average cumulative discounted QALY was 2.11 over the lifetime of a patient. Adjusting for inflation, MRgLITT procedures had a cost-effectiveness of USD 22,211 per QALY. Our sensitivity analysis of cost variables is robust and supports the procedure to be cost--effective.

CONCLUSION

Our data suggests that MRgLITT may be a cost-effective alternative to traditional surgical resection in pediatric epilepsy surgery.

Diagnostic and prognostic value of noninvasive long-term video-electroencephalographic monitoring in epilepsy surgery: A systematic review and meta-analysis from the E-PILEPSY consortium

OBJECTIVE

The European Union-funded E-PILEPSY network (now continuing within the European Reference Network for rare and complex epilepsies [EpiCARE]) aims to harmonize and optimize presurgical diagnostic procedures by creating and implementing evidence-based guidelines across Europe. The present study evaluates the current evidence on the diagnostic accuracy of long-term video-electroencephalographic monitoring (LTM) in identifying the epileptogenic zone in epilepsy surgery candidates.

METHODS

MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov were searched for relevant articles. First, we used random-effects meta-analytical models to calculate pooled estimates of sensitivity and specificity with respect to postsurgical seizure freedom. In a second phase, we analyzed individual patient data in an exploratory fashion, assessing diagnostic accuracy within lesional and nonlesional temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE) patients. We also evaluated seizure freedom rate in the presence of "localizing" or "nonlocalizing" LTM within each group. The quality of evidence was assessed using the QUADAS-2 tool and the GRADE approach.

RESULTS

Ninety-four studies were eligible. Forty-four were included in sensitivity meta-analysis and 34 in specificity meta-analysis. Pooled sensitivity was 0.70 (95% confidence interval [CI] = 0.60-0.80) and specificity was 0.40 (95% CI = 0.27-0.54). Subgroup analysis was based on individual data of 534 patients (41% men). In lesional TLE patients, sensitivity was 0.85 (95% CI = 0.81-0.89) and specificity was -0.19 (95% CI = 0.13-0.28). In lesional ETLE patients, a sensitivity of 0.47 (95% CI = 0.36-0.58) and specificity of 0.35 (95% CI = 0.21-0.53) were observed. In lesional TLE, if LTM was localizing and concordant with resection site, the seizure freedom rate was 247 of 333 (74%), whereas in lesional ETLE it was 34 of 56 (61%). The quality of evidence was assigned as "very low."

SIGNIFICANCE

Long-term video-electroencephalographic monitoring is associated with moderate sensitivity and low specificity in identification of the epileptogenic zone. Sensitivity is remarkably higher in lesional TLE compared to lesional ETLE. Substantial heterogeneity across the studies indicates the need for improved design and quality of reporting.

Neuropsychological outcomes following paediatric temporal lobe surgery for epilepsies: Evidence from a systematic review

OBJECTIVE

The systematic review aimed to assess the neuropsychological outcomes of temporal lobe resections for epilepsy in children. Additional objectives included determining whether earlier age at surgery leads to better neuropsychological outcomes; the relationships between and predictors of these outcomes.

METHODS

Using advanced search terms, a systematic review of electronic databases was conducted, comprising MEDLINE, Embase, PsycINFO, Global Health, Web of Science and CINAHL. Included studies reported on outcome following neurosurgical treatment for epilepsy. Specifically, studies were included if they reported neuropsychological outcomes and were concerned only with temporal lobe resection.

RESULTS

73 studies met inclusion criteria. For reported neuropsychological outcomes, the majority of participants remained stable after surgery; some declined and some improved. There was some evidence for increased material-specific memory deficits after temporal lobe surgery based on resection side, and more positive cognitive outcome for those with lower pre-surgical ability level.

SIGNIFICANCE

Retrieved evidence highlights the need for improvements to quality of methodology and reporting. Appropriately designed prospective multicentre trials should be conducted with adequate follow-up for long-term outcomes to be measured. Core outcome measures should be agreed between centres. This would permit higher quality evidence so that clinicians, young people and their families may make better informed decisions about whether or not to proceed with surgery and likely post-operative profile.

Long-term outcomes of epilepsy surgery in 85 pediatric patients followed up for over 10 years: a retrospective survey

OBJECTIVE The aim of this study was to investigate the treatment outcomes and social engagement of patients who had undergone pediatric epilepsy surgery more than 10 years earlier. METHODS Between 1983 and 2005, 110 patients younger than 16 years underwent epilepsy surgery at the National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders. The authors sent a questionnaire to 103 patients who had undergone follow-up for more than 10 years after surgery; 85 patients (82.5%) responded. The survey contained 4 categories: seizure outcome, use of antiepileptic drugs, social participation, and general satisfaction with the surgical treatment (resection of the epileptic focus, including 4 hemispherectomies). The mean patient age at the time of surgery was 9.8 ± 4.2 (SD) years, and the mean duration of postoperative follow-up was 15.4 ± 5.0 years. Of the 85 patients, 79 (92.9%) presented with a lesional pathology, such as medial temporal sclerosis, developmental/neoplastic lesions, focal cortical dysplasia, and gliosis in a single lobe. RESULTS For 65 of the 85 responders (76.5%), the outcome was recorded as Engel Class I (including 15 [93.8%] of 16 patients with medial temporal sclerosis, 20 [80.0%] of 25 with developmental/neoplastic lesions, and 27 [73.0%] of 37 with focal cortical dysplasia). Of these, 29 (44.6%) were not taking antiepileptic drugs at the time of our survey, 29 (44.6%) held full-time jobs, and 33 of 59 patients (55.9%) eligible to drive had a driver's license. Among 73 patients who reported their degree of satisfaction, 58 (79.5%) were very satisfied with the treatment outcome. CONCLUSIONS The seizure outcome in patients who underwent resective surgery in childhood and underwent followup for more than 10 years was good. Of 85 respondents, 65 (76.5%) were classified in Engel Class I. The degree of social engagement was relatively high, and the satisfaction level with the treatment outcome was also high. From the perspective of seizure control and social adaptation, resective surgery yielded longitudinal benefits in children with intractable epilepsy, especially those with a lesional pathology in a single lobe.

Parenting stress does not normalize after child's epilepsy surgery

PURPOSE

This study aimed to investigate parenting stress expressed by parents before and two years after their children's epilepsy surgery.

SUBJECTS

Parents of 31 consecutively included surgery patients with epilepsy and parents of 31 healthy sex- and age-matched control children were the subjects of this study. Materials and procedure: The questionnaire 'Parenting Stress Index', which distinguishes a Parent domain (stress leading parents to feel themselves inadequate) from a Child domain (child features felt by parent to cause stress) was completed before surgery of the patients and two years thereafter. At both time points, intelligence examination of the child was part of a comprehensive neuropsychological assessment, as were evaluations of recent stress-enhancing life events and epilepsy severity.

RESULTS

Prior to surgery, total parenting stress was significantly higher in parents of patients than in parents of controls. Two years after surgery, total parenting stress had decreased significantly in parents of patients. The scores on parent-related subscales Role Restriction and Spouse and on the child-related subscale Distractibility/Hyperactivity, all relatively high before surgery, decreased significantly. Still, parents of patients experienced significantly more stress compared with parents of controls mainly because of persistently higher stress scores in parents of patients on the subscale Role Restriction (Parent domain) and on five of six subscales in the Child domain. Intelligence of the child was associated with parenting stress: the lower the child's intelligence, the higher the stress score on the subscale Distractibility/Hyperactivity and the lower the stress score on the subscale Mood. Stress decreased more in parents of patients who became seizure-free after surgery than in parents of patients with recurrent seizures.

CONCLUSIONS

Parenting stress decreases but does not normalize in the first two years after epilepsy surgery. Parents should be offered counseling on epilepsy-related intricacies contributing to parenting stress, immediately after diagnosis as well as after epilepsy surgery, notwithstanding the resulting seizure status of the child.

Surgical treatment of pediatric epileptic encephalopathies

Pediatric epileptiform encephalopathies are a group of neurologically devastating disorders related to uncontrolled ictal and interictal epileptic activity, with a poor prognosis. Despite the number of pharmacological options for treatment of epilepsy, many of these patients are drug resistant. For these patients with uncontrolled epilepsy, motor and/or neuropsychological deterioration is common. To prevent these secondary consequences, surgery is often considered as either a curative or a palliative option. Magnetic resonance imaging to look for epileptic lesions that may be surgically treated is an essential part of the workup for these patients. Many surgical procedures for the treatment of epileptiform encephalopathies have been reported in the literature. In this paper the evidence for these procedures for the treatment of pediatric epileptiform encephalopathies is reviewed.

Cognitive outcome after epilepsy surgery in children

The ultimate goal of epilepsy surgery in young children is to stop seizures, interrupt the downhill course of the epileptic encephalopathy, and improve developmental capacities. Postoperative outcome after childhood epilepsy surgery should therefore not only be expressed in terms of seizure freedom, cognitive outcome is an equally important outcome measure. Insight in the mutually dependent variables that can determine pre and postoperative cognitive developmental abilities will improve prediction of outcome and presurgical counseling of parents. The purpose of this review is to discuss the literature regarding cognitive outcome and the predictors of postoperative cognitive functioning after epilepsy surgery in children, particularly those with "catastrophic" epilepsy. There are only few studies in which the relation between possible determinants and cognitive outcome or change was statistically tested in a multivariable manner. Duration of epilepsy, presurgical Developmental Quotient (DQ) or Intelligence Quotient (IQ), and postoperative seizure freedom were the only factors reported in different studies to be independently related to eventual cognitive outcome after epilepsy surgery. Underlying etiology, gender, age at surgery, presurgical DQ/IQ, postoperative seizure freedom, cessation of antiepileptic medication, and follow-up interval have all been described in different surgical cohorts to be independently related to a postoperative change of IQ or DQ scores. To appreciate how each of the pre-epileptic, presurgical, and postoperative variables may independently influence eventual cognitive outcome and postoperative cognitive improvement, we need multicenter studies with large homogenous surgical populations, using standardized tests and multivariable analyses.

'With the benefit of hindsight': would you opt again for epilepsy surgery performed in childhood?

BACKGROUND

How adolescents and their caregivers look back on epilepsy surgery performed in early life, and whether epilepsy-related restrictions are still in force years after the operation, are insufficiently known.

AIMS

To obtain retrospective evaluations of the decision for epilepsy surgery at an early age, and to inventory current epilepsy-related restrictions.

METHODS

Of 177 children who underwent epilepsy surgery between 1992 and 2009, 129 could be approached. They and their parents received a rating list inventorying whether, in retrospect, they would opt again for epilepsy surgery, which were motives for their answer, how successful they felt surgery had been and which, if any, epilepsy-related restrictions were still in force.

RESULTS

Forty-one of 44 seizure-free adolescents and 9 of 10 adolescents with current seizures were inclined to (re-)opt for surgery. Parents also would in majority re-opt for surgery. Age at surgery, post-surgical interval, nor type of surgery was statistically significantly related with re-opting for surgery. Seizure-freedom was the paramount motive of seizure-free respondents; respondents with current seizures in majority mentioned amelioration of seizures and/or medication. For parents of children with current seizures, a better developmental perspective was another important motive. Rare hesitation/refusal was related to uncertainties in weighing advantages and disadvantages. Current seizures were no reason to consider surgery as a failure. Among children who were free of both seizures and anti-epileptic drugs, 42% lived with restrictions.

CONCLUSIONS

Epilepsy surgery that does not result in seizure freedom is nevertheless felt to be beneficial. Proper advice should prevent meaningless continuation of restrictions.

Long-term outcomes of epilepsy surgery in Sweden: a national prospective and longitudinal study

Objective:

To investigate prospective, population-based long-term outcomes concerning seizures and antiepileptic drug (AED) treatment after resective epilepsy surgery in Sweden.

Methods:

Ten- and 5-year follow-ups were performed in 2005 to 2007 for 278/327 patients after resective epilepsy surgery from 1995 to 1997 and 2000 to 2002, respectively. All patients had been prospectively followed in the Swedish National Epilepsy Surgery Register. Ninety-three patients, who were presurgically evaluated but not operated, served as controls.

Results:

In the long term (mean 7.6 years), 62% of operated adults and 50% of operated children were seizure-free, compared to 14% of nonoperated adults (p < 0.001) and 38% of nonoperated children (not significant). Forty-one percent of operated adults and 44% of operated children had sustained seizure freedom since surgery, compared to none of the controls (p < 0.0005). Multivariate analysis identified ≥30 seizures/month at baseline and long epilepsy duration as negative predictors and positive MRI to be a positive predictor of long-term seizure-free outcome. Ten years after surgery, 86% of seizure-free children and 43% of seizure-free adults had stopped AEDs in the surgery groups compared to none of the controls (p < 0.0005).

Conclusions:

This population-based, prospective study shows good long-term seizure outcomes after resective epilepsy surgery. The majority of the patients who are seizure-free after 5 and 10 years have sustained seizure freedom since surgery. Many patients who gain seizure freedom can successfully discontinue AEDs, more often children than adults.

Classification of evidence:

This study provides Class III evidence that more patients are seizure-free and have stopped AED treatment in the long term after resective epilepsy surgery than nonoperated epilepsy patients.

Depth electrodes in pediatric epilepsy surgery

BACKGROUND

The surgical removal of the epileptogenic zone in medically intractable seizures depends on accurate localization to minimize the neurological sequelae and prevent future seizures. To date, few studies have demonstrated the use of depth electrodes in a pediatric epilepsy population. Here, we report our study of pediatric epilepsy patients at our epilepsy center who were successfully operated for medically intractable seizures following the use of intracranial depth electrodes. In addition, we detail three individuals with distinct clinical scenarios in which depth electrodes were helpful and describe our technical approach to implantation and surgery.

METHODS

We retrospectively reviewed 18 pediatric epilepsy patients requiring depth electrode studies who presented at the University of Alberta Comprehensive Epilepsy Program between 1999 and 2010 with medically intractable epilepsy. Patients underwent cortical resection following depth electrode placement according to the Comprehensive Epilepsy Program surgical protocols after failure of surface electroencephalogram and magnetic resonance imaging to localize ictal onset zone.

RESULT

The ictal onset zone was successfully identified in all 18 patients. Treatment of all surgical patients resulted in successful seizure freedom (Engel class I) without neurological complications.

CONCLUSION

Intracranial depth electrode use is safe and able to provide sufficient information for the identification of the epileptogenic zone in pediatric epilepsy patients previously not considered for epilepsy surgery.

Time to pediatric epilepsy surgery is related to disease severity and nonclinical factors

OBJECTIVE

To identify clinical and nonclinical factors associated with time from epilepsy onset to surgical evaluation and treatment among a cohort of children having epilepsy surgery.

METHODS

Data were abstracted from records of 430 children (younger than 18 years) who had epilepsy neurosurgery at the University of California, Los Angeles from 1986 to 2010. Multivariable Cox proportional hazards models were used to analyze unique associations of clinical severity, pre-referral brain MRI, and sociodemographic characteristics with time to surgery.

RESULTS

Shorter time to surgery was associated with active (hazard ratio [HR] 5.67, 95% confidence interval [CI] 3.74-8.70) and successfully treated infantile spasms (HR 2.20, 95% CI 1.63-2.96); daily or more seizures (HR 2.09, 95% CI 1.58-2.76); MRI before referral regardless of imaging findings (HR 1.95, 95% CI 1.47-2.58); private insurance (HR 1.54, 95% CI 1.14-2.09); and Hispanic ethnicity (HR 1.38, 95% CI 1.01-1.87). There were race/ethnicity by insurance interactions (log-rank p = 0.049) with shortest time to surgery for Hispanic children with private insurance.

CONCLUSIONS

Shorter intervals to surgical treatment were associated with greater epilepsy severity and insurance type, consistent with existing literature. However, associations of shorter times to treatment with having a brain MRI before referral and Hispanic ethnicity were unexpected and warrant further investigation. More knowledgeable referring providers and parents with greater help-seeking capability may explain obtaining an MRI before referral. Shorter intervals to surgery among Hispanic children may relate to the same factors yielding an increased volume of Hispanic children receiving surgery at the University of California, Los Angeles since 2000.

Cognitive development from two to ten years after pediatric epilepsy surgery

The development of cognitive functions and the sustainability of seizure control between two and ten years after epilepsy surgery were prospectively investigated in 17 children and adolescents. Intelligence quotient remained stable. Learning capacity improved. Verbal memory improved in half of the subjects and declined in half, whereas figurative memory declined in most patients. Working memory improved as did attention regarding sustained attention and impulse control. In contrast, reaction times were longer, and the auditory attention span was shorter. Executive functions were not affected. Six subjects (35%) were seizure free at the 10-year follow-up, and a seizure reduction of more than 75% had been achieved in 13 (76%). Seizure control improved in five and seizures recurred in two subjects between the two- and the 10-year follow-up.

A retrospective study comparing preoperative evaluations and postoperative outcomes in paediatric and adult patients undergoing surgical resection for refractory epilepsy

PURPOSE

To review and compare the preoperative characteristics and postsurgical outcomes in paediatric and adult patients who underwent surgical resections from 2001 to 2009.

METHODS

Combined data from noninvasive measures such as ictal semiology, interictal/ictal scalp EEGs, MRI and SPECT were utilised to identify the epileptogenic zones (EZ). When noninvasive investigations produced inconclusive or inconsistent findings, patients underwent intracranial EEG monitoring. Resective micro-surgical procedures were conducted according to the results of the anatomo-electro-clinical investigations and were carried out to remove the EZ. We then followed up 222 paediatric (≤18 years old) and 100 adult patients (≥19 years old) for 1-9 years postoperatively.

RESULTS

The mean age of seizure onset in paediatric group was significantly lower than that in adult group. 95 (43%) of the paediatric and 42 (42%) of the adult patients required long-term intracranial EEG recording. 54 (24.3%) of the paediatric and 62 (62%) of the adult patients were found to have temporal lobe epilepsy (TLE), while 149 (67.1%) of the paediatric and 37 (37.0%) of the adult patients had extra-temporal lobe epilepsy (ETLE) (p=0.000). 19 (8.6%) of the paediatric patients and 1 (1%) adult patient had hemispheric lesions (p=0.009). 148 (66.7%) of the paediatric and 61 (61.0%) of the adult patients were seizure-free during the follow-up period. 17 of 19 (89.5%) children who underwent hemispherectomy were seizure-free. In both paediatric and adult groups, the surgical outcome for patients with TLE was significantly better than that of patients with ETLE (p=0.018 in children, p=0.029 in adults). Both the location of EZs and seizure-free ratio were significantly different (p<0.001) between the preadolescent (≤12 years old) and adolescent (13-18 years old) group. Hippocampal sclerosis was the most common pathologic finding in patients with TLE in both groups, and was followed by focal cortical dysplasia. In patients with TLE, the proportion of tumour was significantly higher in the paediatric than the adult group (25.9% vs. 10%, p=0.021).

CONCLUSION

Paediatric patients with refractory seizures had more extratemporal or hemispheric resectable epileptogenic foci and fewer temporal foci than adults. Our study demonstrates that resective surgery is an effective and safe early intervention in strictly selected paediatric patients with refractory epilepsy.

Electrocorticography and seizure outcomes in children with lesional epilepsy

PURPOSE

The use of electrocorticographically (ECoG)-guided cortical resection in children with lesional epilepsy is controversial. Given the important developmental issues associated with recurrent childhood seizures, sustained seizure control is a key therapeutic goal. We therefore evaluated the effect of the decision to perform lesionectomy or ECoG-guided cortical resection on seizure outcome and surgical morbidity in the pediatric population.

METHODS

We retrospectively analyzed seizure outcomes in 67 patients between the ages of 3 months and 16 years who underwent surgery for lesional epilepsy at British Columbia Children's Hospital. Thirty-four patients underwent ECoG, and 33 patients had lesionectomy without ECoG.

RESULTS

One year post-operatively, 80% of patients who had ECoG-guided cortical resection or lesionectomy were seizure free. However, there was a trend toward improved seizure freedom in patients who had ECoG at most recent follow-up (79% patients with ECoG seizure free, vs. 61% with lesionectomy only; mean follow-up time 5.8 year, P=0.078). There was no increase in neurological morbidity in patients who had ECoG-guided cortical resection, and these patients were less likely to experience repeat epilepsy surgery.

CONCLUSIONS

Overall, using ECoG to guide additional cortical resection may lead to more robust seizure freedom in children with lesional epilepsy without increasing their risk of surgical morbidity.

Improved outcomes in pediatric epilepsy surgery: the UCLA experience, 1986-2008

OBJECTIVE

Epilepsy neurosurgery is a treatment option for children with refractory epilepsy. Our aim was to determine if outcomes improved over time.

METHODS

Pediatric epilepsy surgery patients operated in the first 11 years (1986-1997; pre-1997) were compared with the second 11 years (1998-2008; post-1997) for differences in presurgical and postsurgical variables.

RESULTS

Despite similarities in seizure frequency, age at seizure onset, and age at surgery, the post-1997 series had more lobar/focal and fewer multilobar resections, and more patients with tuberous sclerosis complex and fewer cases of nonspecific gliosis compared with the pre-1997 group. Fewer cases had intracranial EEG studies in the post-1997 (0.8%) compared with the pre-1997 group (9%). Compared with the pre-1997 group, the post-1997 series had more seizure-free patients at 0.5 (83%, +16%), 1 (81%, +18%), 2 (77%, +19%), and 5 (74%, +29%) years, and more seizure-free patients were on medications at 0.5 (97%, +6%), 1 (88%, +9%), and 2 (76%, +29%), but not 5 (64%, +8%) years after surgery. There were fewer complications and reoperations in the post-1997 series compared with the pre-1997 group. Logistic regression identified post-1997 series and less aggressive medication withdrawal as the main predictors of becoming seizure-free 2 years after surgery.

CONCLUSIONS

Improved technology and surgical procedures along with changes in clinical practice were likely factors linked with enhanced and sustained seizure-free outcomes in the post-1997 series. These findings support the general concept that clearer identification of lesions and complete resection are linked with better outcomes in pediatric epilepsy surgery 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.

A case study of long-term cognitive and social functioning following a right temporal lobectomy in infancy

We present the rare case of an adult patient, FS, who had a right anterior temporal lobe resection during infancy to treat intractable epilepsy, and underwent a cognitive evaluation 19 years later. Given the paucity of literature on long-term outcomes for infants who receive neurosurgery for epilepsy, this case provides valuable information for both clinicians and patients. What little literature exists on infant and child surgical outcomes for epilepsy suggests a variable course, with several areas of possible cognitive and social difficulty. FS's assessment at the age of 21 revealed only mild difficulties with memory, sequencing, and visual imagery, and spared intellectual functioning, working memory, problem-solving and social cognition, along with a high level of socioeconomic functioning. Thus, the case of FS suggests that neurosurgery during infancy is not necessarily associated with large-scale cognitive impairment, and furthermore, that high levels of functioning both educationally and vocationally are possible after surgical treatment of epilepsy in infancy.

Defining the spectrum of international practice in pediatric epilepsy surgery patients

PURPOSE

The Pediatric Epilepsy Surgery Sub-commission of the International League Against Epilepsy conducted a survey to determine the frequency of epilepsy procedures and etiologies.

METHODS

Data were gathered from 20 programs in the United States, Europe, and Australia on 543 patients (<18 years) for calendar year 2004.

RESULTS

Age at seizure onset was 1 year or less in 46% of patients. Intracranial electrodes were used in 27% of patients. The most common final operation was lobar and focal resections of the frontal and temporal lobes (41%), followed by cerebral hemispherectomy (16%), vagus nerve stimulator (16%), and multilobar resections (13%). Multiple-subpial transections were uncommon procedures (0.6%). The most frequent etiologies were cortical dysplasia (42%), tumors (19%), and atrophic lesions and strokes (10%). Less common were vascular lesions (1.5%), Rasmussen encephalitis (3%), Sturge-Weber (3%), and operations for infantile spasms (4%), and Landau-Kleffner/ESES (<2%). Children <4 years generally presented with daily seizures from cortical dysplasia and underwent multilobar or hemispherectomy. Previous surgeries before 2004 were reported in 22%, and occurred more commonly in patients with tumors (40%), hypothalamic hamartomas (47%), and vascular lesions (67%). U.S. centers reported more vagus nerve stimulator procedures, operated more often on children with no or subtle MRI findings, and used intracranial electrodes and functional neuroimaging more frequently than programs in Europe and Australia.

CONCLUSIONS

The results of this international survey show the feasibility of international collaborations in determining epilepsy etiologies and procedures in children, and suggest differences in clinical practice between regions of the world. These results can guide the design of future studies in producing guidelines for therapy-resistant pediatric epilepsy surgery patients.

Prognosis of chronic and newly diagnosed epilepsy: revisiting temporal aspects

PURPOSE OF REVIEW

The purpose is to review recent papers on the prognosis of epilepsy, with an emphasis on the importance of considering the temporal aspects of epilepsy.

RECENT FINDINGS

The review considers five specific points: What is the chance of spontaneous remission without treatment (i.e. what is the natural history of untreated epilepsy)? What is the prognosis of epilepsy in newly diagnosed patients and how effective is therapy in previously drug-naïve patients? Does delaying treatment make long-term prognosis worse? Is the prognosis of chronic established epilepsy inevitably bad? Refractory epilepsy, pharmaco-resistance and the influence of time.

SUMMARY

This paper reviews the recent evidence that has provided data about temporal aspects of prognosis in epilepsy and confirms the importance of taking a synoptical view of prognosis, incorporating temporal aspects, in making clinical prognostic predictions.