Outcomes after surgery for focal epilepsy in children

Predictive factors for seizure freedom after epilepsy surgery for pediatric low-grade tumors and focal cortical dysplasia

Epilepsy may be drug-resistant in a third of patients necessitating alternative treatments, such as surgery. Among refractory epilepsy patients, the most common etiologies are tumors and focal cortical dysplasia (FCD). Surgical management of tumor-related epilepsy has one of the highest rates of seizure freedom, whereas FCD represents some of the lowest success rates in epilepsy treatment. This study investigates the pre-operative characteristics associated with differences in postsurgical seizure outcomes in patients with FCD and tumors. We completed a retrospective cross-sectional review of epilepsy surgery patients with tumors (n = 29) or FCD (n = 44). Participants had a minimum medical follow-up at least 6 months after surgery (FCD M = 2.1 years; Tumors M = 2.0 years). Patients with FCD trended toward an earlier age of onset (t = -4.19, p = 0.058) and longer epilepsy duration (t = 3.75, p < 0.001). Epilepsy surgery is highly effective in reducing seizures in patients with FCD or tumors with over 70 % of all patients achieving seizure freedom. We found a higher rate of seizure freedom in patients with tumors than FCD, but this difference did not reach significance (79 vs. 66 %). Predictive factors of outcomes for FCD and tumors differ. Findings indicate that diagnostic tests may be differentially sensitive to patients with tumors, and future research is needed.

Focal lesionectomy as surgical treatment of epilepsy in patients with Sturge-Weber syndrome: a case-based systematic review and meta-analysis

OBJECTIVE

Sturge-Weber syndrome (SWS) is a rare neurocutaneous disorder presenting mostly with a facial port-wine stain and leptomeningeal angiomatosis. More than 85% of the patients are affected by epilepsy by the age of 2 years. Seizure and symptom control is the focus of SWS treatment, since no causal therapy exists yet. For pharmacologically intractable epilepsy, surgery is a treatment option. The aim of this systematic review and meta-analysis was to provide an overview of the literature regarding lesionectomy in SWS with a focus on seizure outcome, complications, and motor and cognitive development.

METHODS

The PubMed and Embase databases were searched using a systematic search strategy to identify studies on SWS from their inception until 2021. Two independent researchers assessed the studies for inclusion and quality. Outcome measures were seizure outcome, postoperative complications, and motor and cognitive development. Thereafter, a systematic review was conducted, and a meta-analysis was performed for all included cohort studies. Risk of bias was assessed using the Newcastle-Ottawa Scale. Forest plots have been generated for all outcomes; risk ratio was used for pooled outcomes. A p value < 0.05 was considered as statistically significant.

RESULTS

After removal of duplicates, the authors screened 439 articles, of which 9 articles with 150 patients were included. Our case and 5 case reports and 4 retrospective cohort studies were included for systematic review. The latter 4 studies qualified for the meta-analysis. In these 4 articles, 144 patients received surgical treatment: 81 (56%) underwent focal lesionectomy and 63 (44%) hemispherectomy. Pooled outcome analysis for postoperative favorable seizure outcome showed a nonsignificant difference between lesionectomy and hemispherectomy (69.2% vs 87.3%; RR 0.73, 95% CI 0.50–1.08; t = −2.56, p = 0.08). Lesionectomy showed a significantly lower rate for developmental delay and postoperative hemiparesis in comparison with hemispherectomy (29.8% vs 76.3%; RR 0.41, 95% CI 0.28–0.59; z = −4.77, p < 0.0001 and 18.1% vs 100%; RR 0.11, 95% CI 0.06–0.21; z = −6.58, p < 0.0001, respectively).

CONCLUSIONS

Based on the limited literature available, lesionectomy leads to a nonsignificant lower seizure control rate, while postoperative developmental or motor deficits are significantly lower compared with hemispherectomy. Therefore, focal lesionectomy remains a valid alternative to hemispherectomy in SWS with a clearly localized epileptogenic area; however, individual case-based decisions in a specialized multidisciplinary team are of paramount importance.

Surgical resection of dysembryoplatic neuroepithelioma tumor associated with epilepsy based on imaging classification

OBJECTIVE

Dysembryoplastic neuroepithelioma tumors (DNETs) are rare glioneuronal tumors usually present with partial epilepsy. We analyzed the surgical curative effect of DNETs based on imaging classification.

METHODS

The clinical, neuroimaging, seizure history, neuropathological data, and other medical records of 21 cases of cerebral hemisphere DNETs were collected and analyzed retrospectively. According to the magnetic resonance imaging (MRI) classification of Chassoux, these cases were divided into 8 cases of type I (thylakoid type), 6 cases of type II (nodular type), and 7 cases of type III (dysplasia). All patients received detailed preoperative evaluation and underwent surgical treatment. We statistically compared the postoperative seizure outcome of different DNET MRI types by Engel classification.

RESULTS

All tumors were surgically removed and pathologically diagnosed as DNETs. The follow-up period was 5-68 months Engel class I outcome was achieved in all type I cases, 3 (50%) type II cases, and 3 (42.9%) type III cases. The postoperative seizure outcome of MRI type I was better than that of type II and III.

CONCLUSION

Based on the MRI classification of DNET by Chassoux, the postoperative epilepsy control of type I is better than that of type II and type III, which may be related to the residual FCD around the tumor of type II and type III. Thus, the MRI classification of DNET can contribute to the preoperative design of the resection plan. Total resection of type I and extended resection of type II, as well as type III, will help to improve the postoperative seizure-free rate in DNET.

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.

Surgery for epilepsy

BACKGROUND

This is an updated version of the original Cochrane review, published in 2015.Focal epilepsies are caused by a malfunction of nerve cells localised in one part of one cerebral hemisphere. In studies, estimates of the number of individuals with focal epilepsy who do not become seizure-free despite optimal drug therapy vary between at least 20% and up to 70%. If the epileptogenic zone can be located, surgical resection offers the chance of a cure with a corresponding increase in quality of life.

OBJECTIVES

The primary objective is to assess the overall outcome of epilepsy surgery according to evidence from randomised controlled trials.Secondary objectives are to assess the overall outcome of epilepsy surgery according to non-randomised evidence, and to identify the factors that correlate with remission of seizures postoperatively.

SEARCH METHODS

For the latest update, we searched the following databases on 11 March 2019: Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to March 08, 2019), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs) that included at least 30 participants in a well-defined population (age, sex, seizure type/frequency, duration of epilepsy, aetiology, magnetic resonance imaging (MRI) diagnosis, surgical findings), with an MRI performed in at least 90% of cases and an expected duration of follow-up of at least one year, and reporting an outcome related to postoperative seizure control. Cohort studies or case series were included in the previous version of this review.

DATA COLLECTION AND ANALYSIS

Three groups of two review authors independently screened all references for eligibility, assessed study quality and risk of bias, and extracted data. Outcomes were proportions of participants achieving a good outcome according to the presence or absence of each prognostic factor of interest. We intended to combine data with risk ratios (RRs) and 95% confidence intervals (95% CIs).

MAIN RESULTS

We identified 182 studies with a total of 16,855 included participants investigating outcomes of surgery for epilepsy. Nine studies were RCTs (including two that randomised participants to surgery or medical treatment (99 participants included in the two trials received medical treatment)). Risk of bias in these RCTs was unclear or high. Most of the remaining 173 non-randomised studies followed a retrospective design. We assessed study quality using the Effective Public Health Practice Project (EPHPP) tool and determined that most studies provided moderate or weak evidence. For 29 studies reporting multivariate analyses, we used the Quality in Prognostic Studies (QUIPS) tool and determined that very few studies were at low risk of bias across domains.In terms of freedom from seizures, two RCTs found surgery (n = 97) to be superior to medical treatment (n = 99); four found no statistically significant differences between anterior temporal lobectomy (ATL) with or without corpus callosotomy (n = 60), between subtemporal or transsylvian approach to selective amygdalohippocampectomy (SAH) (n = 47); between ATL, SAH and parahippocampectomy (n = 43) or between 2.5 cm and 3.5 cm ATL resection (n = 207). One RCT found total hippocampectomy to be superior to partial hippocampectomy (n = 70) and one found ATL to be superior to stereotactic radiosurgery (n = 58); and another provided data to show that for Lennox-Gastaut syndrome, no significant differences in seizure outcomes were evident between those treated with resection of the epileptogenic zone and those treated with resection of the epileptogenic zone plus corpus callosotomy (n = 43). We judged evidence from the nine RCTs to be of moderate to very low quality due to lack of information reported about the randomised trial design and the restricted study populations.Of the 16,756 participants included in this review who underwent a surgical procedure, 10,696 (64%) achieved a good outcome from surgery; this ranged across studies from 13.5% to 92.5%. Overall, we found the quality of data in relation to recording of adverse events to be very poor.In total, 120 studies examined between one and eight prognostic factors in univariate analysis. We found the following prognostic factors to be associated with a better post-surgical seizure outcome: abnormal pre-operative MRI, no use of intracranial monitoring, complete surgical resection, presence of mesial temporal sclerosis, concordance of pre-operative MRI and electroencephalography, history of febrile seizures, absence of focal cortical dysplasia/malformation of cortical development, presence of tumour, right-sided resection, and presence of unilateral interictal spikes. We found no evidence that history of head injury, presence of encephalomalacia, presence of vascular malformation, and presence of postoperative discharges were prognostic factors of outcome.Twenty-nine studies reported multi-variable models of prognostic factors, and showed that the direction of association of factors with outcomes was generally the same as that found in univariate analyses.We observed variability in many of our analyses, likely due to small study sizes with unbalanced group sizes and variation in the definition of seizure outcome, the definition of prognostic factors, and the influence of the site of surgery AUTHORS' CONCLUSIONS: Study design issues and limited information presented in the included studies mean that our results provide limited evidence to aid patient selection for surgery and prediction of likely surgical outcomes. Future research should be of high quality, follow a prospective design, be appropriately powered, and focus on specific issues related to diagnostic tools, the site-specific surgical approach, and other issues such as extent of resection. Researchers should investigate prognostic factors related to the outcome of surgery via multi-variable statistical regression modelling, where variables are selected for modelling according to clinical relevance, and all numerical results of the prognostic models are fully reported. Journal editors should not accept papers for which study authors did not record adverse events from a medical intervention. Researchers have achieved improvements in cancer care over the past three to four decades by answering well-defined questions through the conduct of focused RCTs in a step-wise fashion. The same approach to surgery for epilepsy is required.

Invasive Insular Sampling in Pediatric Epilepsy: A Single-Institution Experience

BACKGROUND

It has been increasingly recognized that the insular cortex plays an important role in frontotemporal-parietal epilepsy in children. The insula, however, cannot be properly interrogated with conventional subdural grids, and its anatomy makes it difficult to implicate the insula with semiology or noninvasive modalities. Frame-based, stereotactic placement of insular depth electrodes for direct extraoperative monitoring is a relatively low-risk maneuver that allows for conclusive interrogation of this region, and, in select cases, can easily be replaced with a laser applicator for minimally invasive treatment via thermoablation.

OBJECTIVE

To describe the largest reported series of pediatric patients with refractory epilepsy undergoing insular depth electrode placement.

METHODS

We used current procedural terminology billing records to identify cases of depth electrode insertion performed at our institution. Clinical information from patients undergoing invasive insular sampling was then retrospectively collected.

RESULTS

Seventy-four insular depth electrodes were placed in 49 patients for extraoperative, inpatient monitoring. The decision to place insular depth electrodes was determined by a multidisciplinary epilepsy team. In 65.3% of cases, direct invasive sampling implicated the insula in seizure onset and prompted either thermoablation or surgical resection of some portion of the insula. There were no serious adverse effects or complications associated with the placement of insular depth electrodes.

CONCLUSION

Given the low morbidity of insular depth electrode insertion and the high proportion of patients who exhibited insular involvement, it is worth considering whether insular depth electrodes should be part of the standard presurgical evaluation in children with treatment-refractory frontotemporal-parietal epilepsy.

Medically resistant pediatric insular-opercular/perisylvian epilepsy. Part 2: outcome following resective surgery

OBJECTIVE Seizure onset in the insular cortex as a cause of refractory epilepsy is underrepresented in the pediatric population, possibly due to difficulties localizing seizure onset in deep anatomical structures and limited surgical access to the insula, a complex anatomical structure with a rich overlying vascular network. Insular seizure semiology may mimic frontal, temporal, or parietal lobe semiology, resulting in false localization, incomplete resection, and poor outcome. METHODS The authors retrospectively reviewed the records of all pediatric patients who underwent insular cortical resections for intractable epilepsy at Miami Children's Hospital from 2009 to 2015. Presurgical evaluation included video electroencephalography monitoring and anatomical/functional neuroimaging. All patients underwent excisional procedures utilizing intraoperative electrocorticography or extraoperative subdural/depth electrode recording. RESULTS Thirteen children (age range 6 months-16 years) with intractable focal epilepsy underwent insular-opercular resection. Seven children described symptoms that were suggestive of insular seizure origin. Discharges on scalp EEG revealed wide fields. Four patients were MRI negative (i.e., there were no insular or brain abnormalities on MRI), 4 demonstrated insular signal abnormalities, and 5 had extrainsular abnormalities. Ten patients had insular involvement on PET/SPECT. All patients underwent invasive investigation with insular sampling; in 2 patients resection was based on intraoperative electrocorticography, whereas 11 underwent surgery after invasive EEG monitoring with extraoperative monitoring. Four patients required an extended insular resection after a failed initial surgery. Postoperatively, 2 patients had transient hemiplegia. No patients had new permanent neurological deficits. At the most recent follow-up (mean 43.8 months), 9 (69%) children were seizure free and 1 had greater than 90% seizure reduction. CONCLUSIONS Primary insular seizure origin should be considered in children with treatment-resistant focal seizures that are believed to arise within the perisylvian region based on semiology, widespread electrical field on scalp EEG, or insular abnormality on anatomical/functional neuroimaging. There is a reasonable chance of seizure freedom in this group of patients, and the surgical risks are low.

Surgical strategies for pediatric epilepsy

Pediatric epilepsy is a debilitating condition that impacts millions of patients throughout the world. Approximately 20-30% of children with recurrent seizures have drug-resistant epilepsy (DRE). For these patients, surgery offers the possibility of not just seizure freedom but significantly improved neurocognitive and behavioral outcomes. The spectrum of surgical options is vast, ranging from outpatient procedures such as vagus nerve stimulation to radical interventions including hemispherectomy. The thread connecting all of these interventions is a common goal-seizure freedom, an outcome that can be achieved safely and durably in a large proportion of patients. In this review, we discuss many of the most commonly performed surgical interventions and describe the indications, complications, and outcomes specific to each.

Surgery for epilepsy

BACKGROUND

Focal epilepsies are caused by a malfunction of nerve cells localised in one part of one cerebral hemisphere. In studies, estimates of the number of individuals with focal epilepsy who do not become seizure-free despite optimal drug therapy vary according to the age of the participants and which focal epilepsies are included, but have been reported as at least 20% and in some studies up to 70%. If the epileptogenic zone can be located surgical resection offers the chance of a cure with a corresponding increase in quality of life.

OBJECTIVES

The primary objective is to assess the overall outcome of epilepsy surgery according to evidence from randomised controlled trials.The secondary objectives are to assess the overall outcome of epilepsy surgery according to non-randomised evidence and to identify the factors that correlate to remission of seizures postoperatively.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (June 2013), the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 6), MEDLINE (Ovid) (2001 to 4 July 2013), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) for relevant trials up to 4 July 2013.

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs), cohort studies or case series, with either a prospective and/or retrospective design, including at least 30 participants, a well-defined population (age, sex, seizure type/frequency, duration of epilepsy, aetiology, magnetic resonance imaging (MRI) diagnosis, surgical findings), an MRI performed in at least 90% of cases and an expected duration of follow-up of at least one year, and reporting an outcome relating to postoperative seizure control.

DATA COLLECTION AND ANALYSIS

Three groups of two review authors independently screened all references for eligibility, assessed study quality and risk of bias, and extracted data. Outcomes were proportion of participants achieving a good outcome according to the presence or absence of each prognostic factor of interest. We intended to combine data with risk ratios (RR) and 95% confidence intervals.

MAIN RESULTS

We identified 177 studies (16,253 participants) investigating the outcome of surgery for epilepsy. Four studies were RCTs (including one that randomised participants to surgery or medical treatment). The risk of bias in the RCTs was unclear or high, limiting our confidence in the evidence that addressed the primary review objective. Most of the remaining 173 non-randomised studies had a retrospective design; they were of variable size, were conducted in a range of countries, recruited a wide demographic range of participants, used a wide range of surgical techniques and used different scales used to measure outcomes. We performed quality assessment using the Effective Public Health Practice Project (EPHPP) tool and determined that most studies provided moderate or weak evidence. For 29 studies reporting multivariate analyses we used the Quality in Prognostic Studies (QUIPS) tool and determined that very few studies were at low risk of bias across the domains.In terms of freedom from seizures, one RCT found surgery to be superior to medical treatment, two RCTs found no statistically significant difference between anterior temporal lobectomy (ATL) with or without corpus callosotomy or between 2.5 cm or 3.5 cm ATL resection, and one RCT found total hippocampectomy to be superior to partial hippocampectomy. We judged the evidence from the four RCTs to be of moderate to very low quality due to the lack of information reported about the randomised trial design and the restricted study populations.Of the 16,253 participants included in this review, 10,518 (65%) achieved a good outcome from surgery; this ranged across studies from 13.5% to 92.5%. Overall, we found the quality of data in relation to the recording of adverse events to be very poor.In total, 118 studies examined between one and eight prognostic factors in univariate analysis. We found the following prognostic factors to be associated with a better post-surgical seizure outcome: an abnormal pre-operative MRI, no use of intracranial monitoring, complete surgical resection, presence of mesial temporal sclerosis, concordance of pre-operative MRI and electroencephalography (EEG), history of febrile seizures, absence of focal cortical dysplasia/malformation of cortical development, presence of tumour, right-sided resection and presence of unilateral interictal spikes. We found no evidence that history of head injury, presence of encephalomalacia, presence of vascular malformation or presence of postoperative discharges were prognostic factors of outcome. We observed variability between studies for many of our analyses, likely due to the small study sizes with unbalanced group sizes, variation in the definition of seizure outcome, definition of the prognostic factor and the influence of the site of surgery, all of which we observed to be related to postoperative seizure outcome. Twenty-nine studies reported multivariable models of prognostic factors and the direction of association of factors with outcome was generally the same as found in the univariate analyses. However, due to the different multivariable analysis approaches and selective reporting of results, meaningful comparison of multivariate analysis with univariate meta-analysis is difficult.

AUTHORS' CONCLUSIONS

The study design issues and limited information presented in the included studies mean that our results provide limited evidence to aid patient selection for surgery and prediction of likely surgical outcome. Future research should be of high quality, have a prospective design, be appropriately powered and focus on specific issues related to diagnostic tools, the site-specific surgical approach and other issues such as the extent of resection. Prognostic factors related to the outcome of surgery should be investigated via multivariable statistical regression modelling, where variables are selected for modelling according to clinical relevance and all numerical results of the prognostic models are fully reported. Protocols should include pre- and postoperative measures of speech and language function, cognition and social functioning along with a mental state assessment. Journal editors should not accept papers where adverse events from a medical intervention are not recorded. Improvements in the development of cancer care over the past three to four decades have been achieved by answering well-defined questions through the conduct of focused RCTs in a step-wise fashion. The same approach to surgery for epilepsy is required.

Monitoring the changing pattern of delivery of paediatric epilepsy surgery in England--an audit of a regional service and examination of national trends

PURPOSE

The demand for paediatric epilepsy surgery in the UK greatly exceeds the number of operations performed. Hence, Children's Epilepsy Surgery Service (CESS) was commenced in 2012. This study is aimed to characterise the changes in service delivery in the North East of England Paediatric Neuroscience Network and nationally.

METHODS

A retrospective cohort study of paediatric epilepsy surgery in Leeds between 2005 and 2012 is presented followed by analysis of British Paediatric Neurosurgical Group (BPNG) data before and after CESS commissioning.

RESULTS

During the study period, 42 children underwent epilepsy surgery in Leeds. The commonest aetiologies were neoplasm (33%), focal cortical dysplasia (19%) and mesial temporal sclerosis (19%). Seizure outcome was 71 % EngelI and 83% EngelI+II. Complications included one infection (2%), two temporary (5%) and one permanent (2%) motor deficits, three new/worsened visual field deficits (7%). There were six re-craniotomies (14%). The BPNG data show a 48% increase in paediatric epilepsy surgery in England between 2009 (90 cases) and 2012 (133 cases), and a 20% fall in 2013 (106 cases)--the first calendar year for CESS. On average, 64% of all operations were performed in London.

CONCLUSIONS

The number of children receiving surgery for epilepsy in England had increased annually up to, and declined after, the establishment of CESS centres. The yearly caseload in neurosurgical units outside of London is small. The outcomes from Leeds are comparable to those published elsewhere. Other UK units are encouraged to publish outcomes to facilitate patient, commissioner and provider decision making.

Complications of epilepsy surgery in Sweden 1996–2010: a prospective, population-based study

OBJECT

Detailed risk information is essential for presurgical patient counseling and surgical quality assessments in epilepsy surgery. This study was conducted to investigate major and minor complications related to epilepsy surgery in a large, prospective series.

METHODS

The Swedish National Epilepsy Surgery Register provides extensive population-based data on all patients who were surgically treated in Sweden since 1990. The authors have analyzed complication data for therapeutic epilepsy surgery procedures performed between 1996 and 2010. Complications are classified as major (affecting daily life and lasting longer than 3 months) or minor (resolving within 3 months).

RESULTS

A total of 865 therapeutic epilepsy surgery procedures were performed between 1996 and 2010, of which 158 were reoperations. There were no postoperative deaths. Major complications occurred in 26 procedures (3%), and minor complications in 65 (7.5%). In temporal lobe resections (n = 523), there were 15 major (2.9%) and 41 minor complications (7.8%); in extratemporal resections (n = 275) there were 9 major (3.3%) and 22 minor complications (8%); and in nonresective procedures (n = 67) there were 2 major (3%) and 2 minor complications (3%). The risk for any complication increased significantly with age (OR 1.26 per 10-year interval, 95% CI 1.09–1.45). Compared with previously published results from the same register, there is a trend toward lower complication rates, especially in patients older than 50 years.

CONCLUSIONS

This is the largest reported prospective series of complication data in epilepsy surgery. The complication rates comply well with published results from larger single centers, confirming that epilepsy surgery performed in the 6 Swedish centers is safe. Patient age should be taken into account when counseling patients before surgery.

Volumetric brain analysis in neurosurgery: Part 3. Volumetric CT analysis as a predictor of seizure outcome following temporal lobectomy

OBJECT

The incidence of temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) can be high in developing countries. Current diagnosis of MTS relies on structural MRI, which is generally unavailable in developing world settings. Given widespread effects on temporal lobe structure beyond hippocampal atrophy in TLE, the authors propose that CT volumetric analysis can be used in patient selection to help predict outcomes following resection.

METHODS

Ten pediatric patients received preoperative CT scans and temporal resections at the CURE Children's Hospital of Uganda. Engel classification of seizure control was determined 12 months postoperatively. Temporal lobe volumes were measured from CT and from normative MR images using the Cavalieri method. Whole brain and fluid volumes were measured using particle filter segmentation. Linear discrimination analysis (LDA) was used to classify seizure outcome by temporal lobe volumes and normalized brain volume.

RESULTS

Epilepsy patients showed normal to small brain volumes and small temporal lobes bilaterally. A multivariate measure of the volume of each temporal lobe separated patients who were seizure free (Engel Class IA) from those with incomplete seizure control (Engel Class IB/IIB) with LDA (p<0.01). Temporal lobe volumes also separate normal subjects, patients with Engel Class IA outcomes, and patients with Class IB/IIB outcomes (p<0.01). Additionally, the authors demonstrated that age-normalized whole brain volume, in combination with temporal lobe volumes, may further improve outcome prediction (p<0.01).

CONCLUSIONS

This study shows strong evidence that temporal lobe and brain volume can be predictive of seizure outcome following temporal lobe resection, and that volumetric CT analysis of the temporal lobe may be feasible in lieu of structural MRI when the latter is unavailable. Furthermore, since the authors' methods are modality independent, these findings suggest that temporal lobe and normative brain volumes may further be useful in the selection of patients for temporal lobe resection when structural MRI is available.

Seizures in children with dysembryoplastic neuroepithelial tumors of the brain--A review of surgical outcomes across several studies

PURPOSE

In children and adolescents, dysembryoplastic neuroepithelial tumors (DNETs) of the brain present with seizures almost 100% of the time, potentially creating significant long-term morbidity and disability despite the generally indolent course of the lesion. These tumors also tend to be quite resistant to anti-epileptic drugs which, themselves, can be associated with long-term side effects and resultant disability. Many clinicians advocate early surgical resection of these lesions, but how effective this approach is, and how aggressive tumor removal should be, continues to be debated.

METHODS

We performed a systematic review of the relevant literature to identify all reports of DNET resections in pediatric patients published over the past 20 years. In all, over 3000 MEDLINE abstracts were reviewed, ultimately resulting in 13 studies with 185 pediatric DNET patients to review.

RESULTS

Surgical resection of the lesion was effective at improving seizures in over 98% of patients and at achieving long-term seizure freedom in 86%. Surgical resection of DNETs also appeared to be quite safe, with no reported perioperative deaths and an overall rate of postoperative complications of 12%; the vast majority of these complications were transient.

CONCLUSIONS

Total gross resection of the lesion was the only factor statistically correlated with long-term seizure freedom (r = 0.63, p = 0.03). However, data remain lacking regarding whether this translates into more extensive procedures-like brain mapping and partial lobectomies-being any more effective than simple lesionectomies alone. Further research is clearly needed to address this and other crucial questions.

Magnetoencephalography-guided resection of epileptogenic foci in children

OBJECT

Resective surgery is increasingly used in the management of pediatric epilepsy. Frequently, invasive monitoring with subdural electrodes is required to adequately map the epileptogenic focus. The risks of invasive monitoring include the need for 2 operations, infection, and CSF leak. The aim of this study was to evaluate the feasibility and outcomes of resective epilepsy surgery guided by magnetoencephalography (MEG) in children who would have otherwise been candidates for electrode implantation.

METHODS

The authors reviewed the records of patients undergoing resective epilepsy surgery at the Hospital for Sick Children between 2001 and 2010. They identified cases in which resections were based on MEG data and no intracranial recordings were performed. Each patient's chart was reviewed for presentation, MRI findings, MEG findings, surgical procedure, pathology, and surgical outcome.

RESULTS

Sixteen patients qualified for the study. All patients had localized spike clusters on MEG and most had abnormal findings on MRI. Resection was carried out in each case based on the MEG data linked to neuronavigation and supplemented with intraoperative neuromonitoring. Overall, 62.5% of patients were seizure free following surgery, and 20% of patients experienced an improvement in seizures without attaining seizure freedom. In 2 cases, additional surgery was performed subsequently with intracranial monitoring in attempts to obtain seizure control.

CONCLUSIONS

MEG is a viable alternative to invasive monitoring with intracranial electrodes for planning of resective surgery in carefully selected pediatric patients with localization-related epilepsy. Good candidates for this approach include patients who have a well-delineated, localized spike cluster on MEG that is concordant with findings of other preoperative evaluations and patients with prior brain pathologies that make the implantation of subdural and depth electrodes somewhat problematic.

Safety of Staged Epilepsy Surgery in Children

BACKGROUND:

Surgical resection of epileptic foci relies on accurate localization of the epileptogenic zone, often achieved by subdural and depth electrodes. Our epilepsy center has treated selected children with poorly localized medically refractory epilepsy with a staged surgical protocol, with at least 1 phase of invasive monitoring for localization and resection of epileptic foci.

OBJECTIVE:

To evaluate the safety of staged surgical treatments for refractory epilepsy among children.

METHODS:

Data were retrospectively collected, including surgical details and complications of all patients who underwent invasive monitoring.

RESULTS:

A total of 161 children underwent 200 admissions including staged procedures (&gt;1 surgery during 1 hospital admission), and 496 total surgeries. Average age at surgery was 7 years (range, 8 months to 16.5 years). A total of 250 surgeries included resections (and invasive monitoring), and 189 involved electrode placement only. The cumulative total number of surgeries per patient ranged from 2 to 10 (average, 3). The average duration of monitoring was 10 days (range, 1–30). There were no deaths. Follow-up ranged from 1 month to 10 years. Major complications included unexpected new permanent mild neurological deficits (2%/admission), central nervous system or bone flap infections (1.5%/admission), intracranial hemorrhage, cerebrospinal fluid leak, and a retained strip (each 0.5%/admission). Minor complications included bone absorption (5%/admission), positive surveillance sub-/epidural cultures in asymptomatic patients (5.5%/admission), noninfectious fever (5%/admission), and wound complications (3%/admission). Thirty complications necessitated additional surgical treatment.

CONCLUSION:

Staged epilepsy surgery with invasive electrode monitoring is safe in children with poorly localized medically refractory epilepsy. The rate of major complications is low and appears comparable to that associated with other elective neurosurgical procedures.

Acceptance of epilepsy surgery in the pediatric age - what the parents think and what the doctors can do

Epilepsy surgery (ES) in pediatrics is safe and effective but can be underutilized. Possible barriers could be parental resistance and doctor inertia. We surveyed 138 parents of pediatric patients with epilepsy and found that 25.2% were opposed to this treatment. However, upon completing the questionnaire that contained factual information about ES, 50.4% of the responders stated that they had become more favorable vs. 3.3% more contrary and 46.3% unchanged. Parents of prepubescent patients were most receptive (p=0.0343) and more likely to shift to a more favorable attitude. Thus, pediatric neurologists should not hesitate to discuss ES as soon as indicated, providing all necessary information to increase acceptance. However, among 60 child neurologists surveyed, 60% did not fully comply with guidelines or follow accepted standards of practice, indicating that they may not be apt to provide proper parental guidance. We conclude that education of both practicing neurologists and parents is needed to facilitate the process.

Seizure outcomes of lesionectomy in pediatric lesional epilepsy with brain tumor -- single institute experience

PURPOSE

To determine the clinical characteristics, surgical strategy, and outcome in pediatric lesional epilepsy patients younger than 5years of age undergoing surgery in a single institute.

METHOD

Retrospective data were collected and analyzed on patients younger than 5years of age who underwent lesionectomy for lesional epilepsy at single institute from January 2001 to August 2010. Fourteen pediatric lesional epilepsy patients were enrolled in this study. Engel classification was used to classify seizure outcome.

RESULTS

Median preoperative seizure period was 1month (range, 1-21). Median post-operative follow up period was 35months (range 13-84). Ten patients who underwent gross total resection of tumor showed Engel class Ia seizure outcome without any antiepileptic drug (AED). Subtotal resection was performed in four patients to avoid eloquent area injury. Two of these four patients with subtotal removal became seizure-free (Engel class Ia) without AED, while two were in Engel class Ib with AED medication. There was no significant surgical morbidity or mortality.

CONCLUSION

Lesionectomy in children younger than 5years of age is relatively safe and effective in controlling seizures. Short preoperative seizure periods and total removal of tumor might be associated with good outcome. Therefore, early and complete lesionectomy alone may help allow for seizure freedom and optimal brain development in pediatric patients.

Focal cortical dysplasia is more common in boys than in girls

Genetics and environment likely contribute to the development of medically intractable epilepsy; however, in most patients the specific combination of etiologies remains unknown. Here, we undertook a multicenter retrospective cohort study of sex distribution in pediatric patients undergoing epilepsy surgery and carried out a secondary analysis of the same population subdivided by histopathologic diagnosis. In the multicenter cohort of patients with intractable epilepsy undergoing surgery regardless of etiology (n=206), 63% were boys, which is significantly more boys than expected for the general population (Fisher exact two-tailed p=0.017). Subgroup analysis found that of the 90 patients with a histopathologic diagnosis of focal cortical dysplasia, 72% were boys, giving an odds ratio (OR) of 2.5 (95% CI, 1.34 to 4.62) for male sex. None of the other etiologies had a male sex predominance. Future studies could examine the biological relevance and potential genetic and pathophysiological mechanisms of this observation.

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.

Pediatric temporal lobe epilepsy surgery: resection based on etiology and anatomical location

Advances in electrophysiological assessment with improved structural and functional neuroimaging have been very helpful in the use of surgery as a tool for drug-resistant epilepsy. Increasing interest in epilepsy surgery has had a major impact on adult patients; a refined evaluation process and new criteria for drug resistance combined with refined surgical techniques resulted in large surgical series in many centers. Pediatric surgery has lagged behind this evolution, possibly because of the diverse semiology and electrophysiology of pediatric epilepsy obscuring the focal nature of the seizures and frustrating the treatment of catastrophic epileptic syndromes specific to children. Unfortunately, refractory -epilepsy is more -devastating in children than in adults as it interferes with all aspects of neural development. Nevertheless, during the last few decades, the efforts of a small number of centers with encouraging results in pediatric epilepsy surgery have motivated pediatric neurologists to gain interest. Although well behind in the number of patients compared with that of adults, pediatric series are increasing exponentially. While temporal lobe epilepsy is the focus of interest in adults, with almost 70 % of resections in the temporal lobe, the pediatric epilepsy spectrum is different. Resective or functional surgery techniques devoted to resistant extratemporal epilepsy are the major improvements in pediatric epilepsy surgery. Temporal lobe epilepsy in adults has been studied extensively but only recently has begun to receive attention in children. Several aspects of temporal lobe epilepsy in childhood remain unclear or controversial in terms of seizure semiology and its pathology. This is reflected in the surgical treatment. Information on the major contributors to a favorable outcome, such as type or extent of resection, in terms of seizure control and morbidity is not available as in adult temporal lobe epilepsy. This chapter discusses the major discrepancies between adult and pediatric temporal lobe epilepsy and outlines the current concepts in surgical treatment. The resection strategy based on the different substrates at different locations in the temporal lobe causing seizures is emphasized with respect to available literature.

Seizure outcome after extratemporal epilepsy surgery in childhood

AIM

The aim of the study was to describe seizure outcome following surgery for focal extratemporal epilepsy and identify factors associated with prolonged postsurgical freedom from seizures.

METHOD

In this retrospective cohort study, children with drug-resistant focal extratemporal epilepsy were treated surgically and followed up in a single tertiary care centre between 1997 and 2008.

RESULTS

Eighty children were identified for inclusion in the study (42 males, 38 females; median age 9y 1mo, range 3mo-18y 7mo). The aetiology was identified as focal cortical dysplasia (n=37), low-grade tumour (n=22), tuberous sclerosis (n=9), or non-specific (n=12). Children were followed for a median of 3 years 1 month (range 8mo-10y 7mo) after surgery. Overall, at last follow-up, 50% of the children had been completely seizure free since surgery (Engel class Ia); of these 40 individuals, 15 had discontinued all antiepileptic drugs. Several presurgical factors were associated with a favourable outcome. However, after controlling for confounding factors, aetiology appeared to be the only determinant of long-term seizure outcome as non-specific lesion pathology was associated with seizure recurrence (hazard ratio 10.43; 95% confidence interval 3.26-33.39).

INTERPRETATION

In 50% of cases, children with surgically treated drug-resistant extratemporal epilepsies have an excellent long-term outcome. The aetiology of the epileptogenic lesion appears to be the only significant determinant of surgical outcome in this population of children. It is difficult to correctly identify non-specific pathology on presurgical magnetic resonance imaging.

Epilepsy surgery of the temporal lobe in pediatric population: a retrospective analysis

BACKGROUND

There is still some reluctance to refer pediatric patients for epilepsy surgery, despite evidence of success in retrospective series.

OBJECTIVE

To describe surgical experience and long-term outcome in pediatric temporal lobe epilepsy (TLE) at a single institution.

METHODS

Retrospective review of pediatric (<18-years-old) TLE patients who underwent surgery between November 1996 and December 2006 at Cleveland Clinic Epilepsy Center. Cox proportional hazard modeling was used to assess outcome predictors.

RESULTS

One hundred thirty pediatric patients met study criteria. Mean time between seizure onset and surgery was 6.3 years. Invasive evaluation was used in 32 patients (24.5%). Hippocampal sclerosis was present in 70 patients (53.8%), either alone or associated in dual pathology. The complication rate was 7%. The seizure-freedom rates at 1, 2, 5, and 12 years were 76%, 72%, 54%, and 41%, respectively (Kaplan-Meier). With the use of the Engel outcome classification, 98 (75.3%) patients were class I, 11 (8.5%) class II, 9 (7%) class III, and 12 (9.2%) were class IV at last follow-up. Only 4 (3.1%) patients underwent reoperations. Antiepileptic drugs (AEDs) were discontinued in 36 patients (28.3%) in a mean period of 18 months (SD ± 17 months; range, 6-102 months). Although left-sided resection, lower number of preoperative AED trials (≤ 4), and tumor pathology correlated with favorable seizure outcomes, extensive surgical resection remained the only significant outcome predictor after multivariate analysis (P = .007; HR = 0.13 [95% confidence interval 0.007-0.64]).

CONCLUSION

Careful selection of surgical candidates by multidisciplinary evaluations is required. Long-term seizure control is achieved successfully with acceptable low complication rates.

Individually tailored extratemporal epilepsy surgery in children: anatomo-electro-clinical features and outcome predictors in a population of 53 cases

Surgery for refractory extratemporal lobe epilepsy (ETLE) in the pediatric age group has been reported to be associated with a high percentage of failure and relapse. We performed a retrospective study of 53 consecutive patients with epilepsy onset before 12 years of age, who underwent, mostly at a pediatric age, an individually tailored ETLE surgery (32 in frontal and 21 in posterior cerebral areas) for pharmacoresistant seizures; these patients were selected and followed by a single national tertiary care pediatric center. Mean age at seizure onset was 3.14 years, and mean age at surgery was 11.23 years. Complete seizure freedom was achieved in 75% of the subjects. Short duration of illness before surgery, MRI features, no invasive pre-surgical evaluation, a localized interictal and ictal pattern as well as the presence of ictal fast activity on scalp EEG, localized interictal fast rhythms and absence of a diffuse initial ictal modification during SEEG, a complete resection of the epileptogenic zone, a type II FCD, and the absence of acute postoperative seizures correlated in a statistically significant way with a seizure-free outcome. We conclude that the seizure outcome of ETLE surgery in a carefully selected pediatric population can be excellent.

Neuropsychological outcome after extra-temporal epilepsy surgery

BACKGROUND

The neuropsychological results of temporal lobe epilepsy surgery are well reported in the literature. The aim of this study was to analyse the neuropsychological outcome in a consecutive series of patients with extra-temporal epilepsy.

METHODS

We retrospectively analysed the data of patients operated between 1996 and 2008 for extra-temporal epilepsy. Standard neuropsychological tests were applied. We assessed the neuropsychological outcome after surgery and the correlation of the neuropsychological outcome with (1) side and localisation of surgery, (2) Engel scale for seizure outcome and (3) timing of surgery.

FINDINGS

Patients had a better neuropsychological outcome when undergoing non-frontal resection [χ2 (2) =6.66, p = 0.036]. Subjects who had undergone left or right resection showed no difference in outcome [χ2 (2) =0.533, p = 0.766]. The correlation between the Engel scale for seizure re-occurence and the neuropsychological scores showed only a tendency for better outcome (Spearman ρ = -0.437; p = 0.069). The global measure of change did not correlate significantly with delay of surgery (Spearman ρ = -0.163; p = 0.518).

CONCLUSIONS

Resective epilepsy surgery improves neuropsychological status outcome in patients with extra-temporal epilepsy even if the patient did not become seizure free. The outcome is better for non-frontal localisation.

Association of magnetic resonance imaging identification of mesial temporal sclerosis with pathological diagnosis and surgical outcomes in children following epilepsy surgery

OBJECT

Mesial temporal sclerosis (MTS) is widely recognized as a significant underlying cause of temporal lobe epilepsy. Magnetic resonance imaging is routinely used in the preoperative evaluation of children with epilepsy. The purpose of this study was to evaluate the prevalence, reliability, and prognostic value of MRI identification of MTS and MRI findings indicative of MTS in a series of patients who underwent resection of the medial temporal lobe for medically refractory epilepsy.

METHODS

The authors reviewed the medical records and preoperative MRI reports of 25 patients who had undergone medial temporal resections (anterior temporal lobectomy or functional hemispherotomy) for medically intractable epilepsy. The preoperative MRI studies were presented for blinded review by 2 neuroradiologists who independently evaluated the radiographs for selected MTS features and provided a final interpretation. To quantify interrater agreement and accuracy, the findings of the 2 blinded neuroradiologists, the nonblinded clinical preoperative radiology report, and the final pathology interpretation were compared.

RESULTS

The preoperative MRI studies revealed MTS in 6 patients (24%), and histopathological analysis verified MTS in 8 (32%) of 25 specimens. Six MRI features of MTS were specifically evaluated: 1) increased hippocampal signal intensity, 2) reduced hippocampal size, 3) atrophy of the ipsilateral hippocampal collateral white matter, 4) enlarged ipsilateral temporal horn, 5) reduced gray-white matter demarcation in the temporal lobe, and 6) decreased temporal lobe size. The most prevalent feature of MTS identified on MRI was a reduced hippocampal size, found in 11 of the MRI studies (44%). Analysis revealed moderate interrater agreement for MRI identification of MTS between the 2 blinded neuroradiologists and the nonblinded preoperative report (Cohen κ 0.40-0.59). Interrater agreement was highly variable for different MTS features indicative of MTS, ranging from poor to near perfect. Agreement was highest for increased hippocampal signal and decreased temporal lobe size and was consistently poor for reduced gray-white matter demarcation. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and proportion perfect agreement were highest for increased hippocampal signal and reduced hippocampal size. An MRI finding of MTS was not predictive of seizure outcome in this small series.

CONCLUSIONS

Mesial temporal sclerosis identification on brain MRI in children evaluated for medial temporal resections has a PPV of 55%-67% and an NPV of 79%-87%. Increased hippocampal signal and reduced hippocampal size were associated with high predictive values, while gray-white differentiation and an enlarged temporal horn were not predictive of MTS. Seizure outcome following medial temporal resections was not associated with MRI findings of MTS or MRI abnormalities indicative of MTS in this small sample size.

Paediatric intractable epilepsy syndromes: changing concepts in diagnosis and management

Epilepsy surgery for drug-resistant childhood epilepsy is not new. However, brain imaging, surgical and anaesthetic techniques have improved to the extent that they are now as much safer and realistic option than they were in the past. Further, the range of surgical candidates is wide, and previous concepts about likely surgical candidates are now challenged as children with previously thought widespread or apparent multifocal disease are evaluated. Outcomes for seizure freedom range from 40 to 80 % depending on the underlying aetiology and the extent of resection. However, the aims of surgery may include seizure reduction in some and improvement in neurodevelopment and behaviour in others, which are less -predictable. Epilepsy surgery in children is no longer a last resort. Children thought to be likely candidates should be evaluated early in their natural history to optimise outcomes in the long term.

Long-term outcome in children with intractable epilepsy showing bilateral diffuse cortical glucose hypometabolism pattern on positron emission tomography

The objective of this study is to determine the long-term outcome of children with intractable epilepsy who have diffuse cortical hypometabolism on 2-deoxy-2-((18)F)fluoro-D-glucose positron emission tomography (FDG-PET) scans. Seventeen children with intractable epilepsy showing bilateral, diffuse cortical hypometabolism on FDG-PET were followed up through telephone interview from 1 year 4 months to 11 years 4 months (mean: 5 years 7 months ± 2 years 1 month) after their PET scans. One child succumbed to Sanfilippo disease at age 20 years. Only 2 children were seizure free. Fifty percent had walking difficulties, 56.25% were not toilet trained, all had speech difficulties, 43.75% had behavioral problems, 37.5% had poor eye contact, 75% had socialization difficulties, and 87.5% attended special schools. Three children were found to have genetic causes, including a 4-MB deletion of the mitochondrial genome, MECP2 duplication, and Lafora disease. In conclusion, the long-term outcome in this patient population is poor, and they tend to suffer from genetic/neurodegenerative diseases.

Pediatric temporal low-grade glial tumors: epilepsy outcome following resection in 48 children

PURPOSE

This paper summarizes our experience with surgical treatment of pediatric low-grade glial temporal lobe tumors focusing on the long-term outcome of seizures and identifying factors associated with seizure control and failure.

METHODS

We reviewed all medical records of pediatric patients that underwent temporal lobe surgery due to seizures at our institution between 1997 and 2009. Only patients with temporal lobe tumors were included in this series. The files were retrospectively reviewed for seizure history. All children had undergone pre- and postoperative evaluation, neurological examination, EEG, and MRI.

RESULTS

The cohort includes 48 children with mean follow-up time of 5.15 years (1-12 years). The mean age at surgery was 8.2 years (1-18.1) and the mean seizure duration until surgery was 2.6 years. All lesions in the cohort were low-grade tumors; pilocytic astrocytoma was the most common (41%). Eighty-three percent of the patients were classified as Engel class I following surgery. There was no correlation between Engel score and the preoperative epilepsy duration, age of seizure onset or type of seizures, and pathology. The surgical complication rate was 4.1% (2/48).

CONCLUSIONS

Surgical treatment for seizure control in children and adolescents with low-grade temporal tumors provides excellent long-term results.

Extratemporal, nonlesional epilepsy in children: postsurgical clinical and neurocognitive outcomes

OBJECT

Patients undergoing epilepsy surgery without evidence of a lesion on MR imaging and without a temporal source for seizure onset generally have less favorable outcomes than patients with structural lesions or temporal onset. However, many of these patients are viable candidates for invasive monitoring and subsequent resection or multiple subpial transections (MSTs). The purpose of this study was to evaluate the surgical treatment of pediatric patients with extratemporal, nonlesional epilepsy in order to better understand the clinical and neuropsychological outcomes expected in this patient group.

METHODS

Forty-three pediatric patients with negative results on MR imaging and lateralized, extratemporal findings on electroencephalography underwent invasive monitoring with grid and/or strip electrodes. Thirty-three subsequently had resection of an epileptogenic focus and/or MSTs.

RESULTS

Outcome was classified as Engel class I or II in 54.5% of the patients who underwent resection/MSTs and Engel class III or IV in 45.5%. Use of MSTs was associated with poor outcome. Neuropsychological evaluation showed significant improvement in immediate auditory attention following surgery and revealed several significant results on subgroup analysis. Complications occurred in 14% of patients (a 7% rate per procedure). Ten patients (23%) underwent invasive monitoring without proceeding to therapeutic surgery because no epileptogenic region was amenable to resection. Neuropsychological outcomes were generally stable.

CONCLUSIONS

Patients with extratemporal, nonlesional seizures are viable candidates for invasive monitoring with grid/strip electrodes, and good outcomes can be obtained with resective surgery. The use of MSTs may correlate with worse outcome. This study also provides additional data to assist in counseling patients on the risks of negative invasive monitoring, deficits resulting from resection/MSTs, and possible operative complications.

Epilepsy surgery in children compared to adults

AIM

The purpose of this study was to compare the frequency of various surgical techniques and surgical outcome between pediatric and adult populations that underwent epilepsy surgery by the same team.

METHODS

All patients who underwent epilepsy surgery at the Tel Aviv Medical Center between 1997 and 2006 and had been followed up for >2 years were eligible for this study. The majority (90%) of all epilepsy surgeries carried out in Israel were performed in this institution and by a single neurosurgeon. Only patients that underwent video-EEG monitoring as part of the presurgical evaluation were included in the study.

RESULTS

A total of 186 patients (131 adults and 55 children) underwent epilepsy surgery in our institute during the study period, and follow-up was available for 177 patients (95%). While the adults underwent significantly more temporal lobe resections (51 vs. 20%, p < 0.0001), the children had significantly more extra-temporal non-lesional resections (18 vs. 1%, p < 0.0001) and hemispherectomies (5 vs. 1%, p = 0.002). Over one half (54%) of all the patients had a postoperative reduction in seizures of >90%, and 72% had a reduction of >50%, with no group difference in surgical success. Among the lesionectomies, the outcome was better for tumors, especially those in the temporal lobe. Only 1% of the patients had a long-term neurological deficit.

CONCLUSIONS

Children comprised 30% of the epilepsy surgical cases during the study period. Children underwent more non-lesional resections and hemispherectomies, while adults underwent more temporal lobe resections. There was no age-related difference in surgical outcome.

[Quality of life following extratemporal epilepsy surgery]

Extratemporal epileptic foci are increasingly treated successfully with surgery. This study assesses the effect of extratemporal epilepsy surgery on the subjective handicaps of epilepsy patients. Twenty-one adults with pharmacoresistant focal epilepsy undergoing extratemporal surgical interventions were analyzed compared to an age-, gender-, and IQ-matched patient group with temporal lobe epilepsy. A questionnaire on subjective handicaps was given prior to surgery and after 1 year of follow-up. There were significant postoperative improvements in the domains of work and activities, self perception, and judgement of changes in handicap. These changes were similar to those in patients undergoing temporal lobe surgery and not restricted to those achieving complete seizure remission. Epilepsy surgery thus improves not only seizure control but also quality of life in patients with extratemporal focus localization.

Comparative role of neuropsychological testing in the presurgical evaluation of children with medically intractable epilepsies

PURPOSE

In the present study, we evaluated the preoperative demographic, clinical, and neuropsychological variables that could predict postoperative seizure outcome in a group of pediatric epileptic patients.

MATERIALS AND METHODS

We studied 40 consecutive pediatric patients, ages ranging from 6 to 16 years, that underwent resective surgery for the treatment of medically intractable epilepsy at the Clinical Hospital of Ribeirão Preto School of Medicine. We performed ictal electroencephalography (EEG), interictal EEG, magnetic resonance imaging (MRI), and a preoperative neuropsychological assessment in the presurgical workup.

RESULTS

The following factors were correlated with seizure outcome: (1) duration of epilepsy, (2) surgery localization, (3) localized Neuropsychological (NPS) Evaluation, (4) ictal EEG, (5) interictal EEG, and (6) MRI. Mental retardation, NPS tests, and the other demographic variables failed to correlate with seizure reduction.

CONCLUSIONS

The identification of predictor variables of epilepsy surgery outcome could improve the epileptic prognosis and guarantee the children's full potential development.

Benign lesions accompanied by intractable epilepsy in children

Epilepsy surgery has been proposed as a safe alternative treatment for intractable epilepsy in children, especially for patients with structural brain abnormalities. We studied 24 consecutive children who underwent surgery for intractable epilepsy. There were 12 males and 12 females. The mean age was 6.5 years. The seizures' duration ranged from 6 months to 2 years. The histopathological examination of the resected lesions revealed in 12 cases the presence of a ganglioglioma, in 7 cases dysembryoplastic neuroepithelial tumor, in 1 case a low grade glioma, in 2 cases cortical dysplasia, and in 2 cases cavernous malformations. In 18 cases, the lesions were located in the temporal lobe and in 6 cases the lesions were extratemporal. After a mean follow-up period of 4.4 years, 79% (19/24) of patients were seizure free. There were no permanent neurological deficits or deaths. Surgery for focal epilepsy in children is a safe procedure with favorable results.