Practice parameter: temporal lobe and localized neocortical resections for epilepsy: report of the Quality Standards Subcommittee of the American Academy of Neurology, in association with the American Epilepsy Society and the American Association of Neurological Surgeons

Referral trends for temporal lobe epilepsy surgery between 2000 and 2014 in India

BACKGROUND

We conducted a retrospective study examining the trends in referral to a tertiary epilepsy surgery center in India over 2 decades.

METHODS

Data of patients who underwent long-term video electro encephalography monitoring for presurgical evaluation were retrospectively analyzed. Patients aged >16 years and diagnosed to have drug-resistant temporal lobe epilepsy (TLE) were included. They were divided into 3 groups comprising 5-year periods each during which they underwent presurgical evaluation, group 1: year 2000-2004; group 2: year 2005-2009; and group 3: year 2010-2014. Referral data with particular reference to duration of epilepsy before referral, age at onset of seizures, and number of antiepileptic drugs tried before referral were analyzed.

RESULTS

A total of 1362 patients fulfilled the inclusion criteria. There were 385 referrals in group 1, 488 in group 2, and 489 in group 3. The mean duration of epilepsy before referral was 18.10 ± 9.44 years; there was no change in the duration of epilepsy before referral (p = 0.638). A significant increase in the age at onset of seizures and age at presurgical evaluation was noted over time.

CONCLUSION

There is evidence for delayed referral of patients with refractory TLE to a surgical epilepsy center in this study. Renewed efforts to confront challenges beholding epilepsy surgery and steps to ensure timely referral are desirable.

Predictors of meaningful improvement in quality of life after selective amygdalohippocampectomy in Chinese patients with refractory temporal lobe epilepsy: A prospective study

PURPOSE

Our aim was to determine the independent predictors of minimum clinically important difference (MCID) in quality of life (QOL) after selective amygdalohippocampectomy (SAH) among Chinese patients with refractory mesial temporal lobe epilepsy (MTLE).

METHODS

We conducted a prospective study and enrolled 50 consecutive patients with refractory MTLE who underwent SAH after their presurgical evaluations. The variables independently associated with MCID in the Quality of Life in Epilepsy Inventory-31 (QOLIE-31) overall score 1 year after SAH were analyzed by multiple binary logistic regression analysis.

RESULTS

Significant improvements in the QOLIE-31 overall score and all subscale scores were observed after SAH (p < 0.001). Among 50 patients with refractory MTLE, 78% reached the criteria for MCID of QOL overall score after SAH. In the multiple binary logistic regression model, the presurgical independent predictors of significant improvement by MCID in QOL were absence of depression diagnosis (adjusted odds ratio [OR] = 8.391, 95% confidence interval [CI] = 1.240-56.776, p = 0.029) and good cognitive function (adjusted OR = 8.427, 95% CI = 1.115-63.670, p = 0.039); the postoperative independent predictor was seizure freedom (adjusted OR = 8.477, 95% CI = 1.195-60.122, p = 0.032). The sensitivity and specificity for significant improvement in the QOL were 97.4% and 45.5% respectively, with an overall model accuracy of 86.0%.

CONCLUSIONS

Presurgical depression, cognitive function, and postsurgical seizure freedom are independent predictors for meaningful improvement in QOL after SAH among the Chinese patients with refractory MTLE. Preoperative evaluation of patients with refractory MTLE should consider the cognitive dysfunction and psychological disorders.

Impact of surgical intervention on seizure and psychiatric symptoms in patients with temporal lobe epilepsy

Temporal lobe epilepsy (TLE), a common form of localisation-related epilepsy, is characterised by focal seizures and accompanied by variety of neuropsychiatric symptoms. This form of epilepsy proves difficult to manage as many anticonvulsant and psychotropic medications have little to no effect on controlling the seizure and neuropsychiatric symptoms respectively. The authors, report a patient with TLE and recurrent seizures that were refractory to multiple classes of antiepileptic therapy. Additionally, she exhibited psychosis, depression and irritability that required antipsychotic medication. After several years of poorly controlled seizure disorder, the patient underwent anterior temporal lobectomy and amygdalohippocampectomy, which proved beneficial for seizure control, as well as her neuropsychiatric symptoms. While it is common to treat refractory temporal lobe epilepsy with surgical interventions, there is little literature about it also treating the neuropsychiatric symptoms. This case underscores both the neurological and psychiatric benefits following surgical intervention for patients with TLE.

Stereotyped high-frequency oscillations discriminate seizure onset zones and critical functional cortex in focal epilepsy

High-frequency oscillations in local field potentials recorded with intracranial EEG are putative biomarkers of seizure onset zones in epileptic brain. However, localized 80-500 Hz oscillations can also be recorded from normal and non-epileptic cerebral structures. When defined only by rate or frequency, physiological high-frequency oscillations are indistinguishable from pathological ones, which limit their application in epilepsy presurgical planning. We hypothesized that pathological high-frequency oscillations occur in a repetitive fashion with a similar waveform morphology that specifically indicates seizure onset zones. We investigated the waveform patterns of automatically detected high-frequency oscillations in 13 epilepsy patients and five control subjects, with an average of 73 subdural and intracerebral electrodes recorded per patient. The repetitive oscillatory waveforms were identified by using a pipeline of unsupervised machine learning techniques and were then correlated with independently clinician-defined seizure onset zones. Consistently in all patients, the stereotypical high-frequency oscillations with the highest degree of waveform similarity were localized within the seizure onset zones only, whereas the channels generating high-frequency oscillations embedded in random waveforms were found in the functional regions independent from the epileptogenic locations. The repetitive waveform pattern was more evident in fast ripples compared to ripples, suggesting a potential association between waveform repetition and the underlying pathological network. Our findings provided a new tool for the interpretation of pathological high-frequency oscillations that can be efficiently applied to distinguish seizure onset zones from functionally important sites, which is a critical step towards the translation of these signature events into valid clinical biomarkers.awx374media15721572971001.

Optimization of surgical intervention outside the epileptogenic zone in the Virtual Epileptic Patient (VEP)

Studies to improve the efficacy of epilepsy surgery have focused on better refining the localization of the epileptogenic zone (EZ) with the aim of effectively resecting it. However, in a considerable number of patients, EZs are distributed across multiple brain regions and may involve eloquent areas that cannot be removed due to the risk of neurological complications. There is a clear need for developing alternative approaches to induce seizure relief, but minimal impact on normal brain functions. Here, we develop a personalized in-silico network approach, that suggests effective and safe surgical interventions for each patient. Based on the clinically identified EZ, we employ modularity analysis to identify target brain regions and fiber tracts involved in seizure propagation. We then construct and simulate a patient-specific brain network model comprising phenomenological neural mass models at the nodes, and patient-specific structural brain connectivity using the neuroinformatics platform The Virtual Brain (TVB), in order to evaluate effectiveness and safety of the target zones (TZs). In particular, we assess safety via electrical stimulation for pre- and post-surgical condition to quantify the impact on the signal transmission properties of the network. We demonstrate the existence of a large repertoire of efficient surgical interventions resulting in reduction of degree of seizure spread, but only a small subset of them proves safe. The identification of novel surgical interventions through modularity analysis and brain network simulations may provide exciting solutions to the treatment of inoperable epilepsies.

We propose a personalized in-silico surgical approach able to suggest effective and safe surgical options for each epilepsy patient. In particular, we focus on deriving effective alternative methods for those cases where EZs are inoperable because of issues related with neurological complications. Based on modularity analysis using structural brain connectivity from each patient, TZs that would be considered as surgical sites are obtained. The acquired TZs are evaluated by personalized brain network simulations in terms of effectiveness and safety. Through the feedback approach combining modularity analysis and brain network simulations, the optimized TZ options that minimize seizure propagation while not affecting normal brain functions are obtained. Our study has a great importance in that it demonstrates the possibility of computational neuroscience field being able to construct a paradigm for personalized medicine by deriving innovative surgical options suitable for each patient and predicting the surgical outcomes.

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.

Fifteen-minute consultation: When medicines don't work-the child with poorly controlled seizures

Drug-resistant epilepsy (DRE) occurs in 20%-30% of children with epilepsy with significant impact on their quality of life. Management of this group of children has greatly improved in the recent years with streamlining of epilepsy surgery services and associated quaternary multimodal evaluation. This article provides a review of DRE in children and management based on recent evidence and published opinion. We have also presented an algorithmic approach to the child with possible DRE.

Prognostic factors of postoperative seizure outcome in patients with temporal lobe epilepsy and normal magnetic resonance imaging

PURPOSE

To retrospectively analyse a single-centre consecutive surgical series of patients with temporal lobe epilepsy (TLE) and negative MRI. To identify factors associated with postoperative seizure outcome among several presurgical, surgical and postsurgical variables.

METHODS

Clinical records of 866 patients who received temporal lobe resections and with a minimum follow-up of 12 months were retrospectively searched for MRI-negative cases. Anamnestic, clinical, neurophysiological, surgical, histopathological and postsurgical data were collected. Seizure outcome was categorised as favourable (Engel's class I) and unfavourable (Engel's classes II-IV). Uni- and multivariate statistical analysis was performed to identify variables having a significant association with seizure outcome.

RESULTS

Forty-eight patients matched the inclusion criteria. 26 (54.1%) patients required invasive EEG evaluation with Stereo-electro-encephalography (SEEG) before surgery. Histological evaluation was unremarkable in 34 cases (70.8%), revealed focal cortical dysplasias in 13 cases and hippocampal sclerosis in 2. 28 (58.3%) patients were in Engel's class I after a mean follow-up of 82 months (SD ± 74; range 12-252). Multivariate analysis indicated auditory aura, contralateral diffusion of the discharge at Video-EEG monitoring and use of ¹⁸F-FDG PET as variables independently associated with seizure outcome.

CONCLUSION

Carefully selected patients with MRI-negative TLE can be good candidates for surgery. Surgery should be considered with caution in patients with clinical features of neocortical seizure onset and contralateral propagation of the discharge. Use of ¹⁸F-FDG PET may be helpful to improve SEEG and surgical strategies. The presented data help in optimising the selection of patients with MRI-negative TLE with good chances to benefit from surgery.

From Resection to Disconnection for Seizure Control in Pediatric Epilepsy Children

Epilepsy surgery revealed dramatically improved seizure outcomes over medical therapy in drug-resistant epilepsy patients. Children with epilepsy, however, have multiple epileptic focuses which require multilobar resection for better seizure outcome. Multilobar resection has not only the several severe surgical complications, such as hydrocephalus and shunt-related craniosynostosis, due to intracranial volume reduction. Isolation method (disconnection surgery) was progressively studied over epileptic focus removal (resective surgery) for seizure control. This concept was first introduced for functional hemispherotomy, and its primary principle is to preserve the vital vascularized brain that is functionally disconnected from the contralateral healthy brain. Currently in most epilepsy centers, the predominant disconnection surgical methods, including functional hemispherotomy, are continually being refined and are showing excellent results. They allow the functional isolation of the hemisphere or multi-lobe, affected by severe epilepsy. This review describes recent findings concerning the indication, surgical technique, seizure outcome and complications in several disconnection surgeries including the functional hemispherotomy for refractory pediatric epilepsy.

Establishment of low cost epilepsy surgery centers in resource poor setting

PURPOSE

To prospectively assess the feasibility of establishing low cost epilepsy surgery programs in resource poor settings.

METHOD

We started epilepsy surgery centers in Tier 2 and Tier 3 cities in India in private hospitals. This model is based on the identifying and operating ideal epilepsy surgery candidates on the basis of clinical history, interictal and ictal video-EEG data, and 1.5 T MRI without other investigations and without regular involvement of other specialists. Trained epileptologists formed the fulcrum of this program who identified ideal candidates, offered them counseling, and read video-EEG and MRI. We also spread epilepsy awareness among locals and physicians and established focused epilepsy clinics. The expenses were subsidized for deserving patients and policies were devised to keep video-EEG duration and staff requirement to minimum. Difficult epilepsy surgery cases were referred to established centers. Initial surgeries were performed by invited epilepsy surgeons and subsequently by local neurosurgeons.

RESULTS

A total of 125 epilepsy surgeries were performed at three centers since 2012. This included 81(64.8%) temporal lobe resections, 26 (20.8%) extratemporal focal resections, and 13 (10.4%) hemispherotomies. Of the 93 patients with more than 1 year of postoperative followup, 86 (92.5%) had Engel class IA outcome. There were minor complications in 5% patients. Average cost of presurgical evaluation and surgery was Rs. 92,707 (USD 1,324).

CONCLUSIONS

It is possible to establish successful epilepsy surgery programs in resource poor setting with reasonable costs. This low cost model can be replicated in other parts of world to reduce the surgical treatment gap.

Promoting faster pathways to surgery: a clinical audit of patients with refractory epilepsy

Background

Individuals with epilepsy who cannot be adequately controlled with anti-epileptic drugs, refractory epilepsy, may be suitable for surgical treatment following detailed assessment. This is a complex process and there are concerns over delays in referring refractory epilepsy patients for surgery and subsequent treatment. The aim of this study was to explore the different patient pathways, referral and surgical timeframes, and surgical and medical treatment options for refractory epilepsy patients referred to two Tertiary Epilepsy Clinics in New South Wales, Australia.

Methods

Clinical records were reviewed for 50 patients attending the two clinics, in two large teaching hospitals (25 in Clinic 1; 25 in Clinic 2. A purpose-designed audit tool collected detailed aspects of outpatient consultations and treatment. Patients with refractory epilepsy with their first appointment in 2014 were reviewed for up to six visits until the end of 2016. Data collection included: patient demographics, type of epilepsy, drug management, and assessment for surgery. Outcomes included: decisions regarding surgical and/or medical management, and seizure status following surgery. Patient-reported outcome measures to assess anxiety and depression were collected in Clinic 1 only.

Results

Patient mean age was 38.3 years (SD 13.4), the mean years since diagnosis was 17.3 years (SD 9.8), and 88.0% of patients had a main diagnosis of focal epilepsy. Patients were taking an average of 2.3 (SD 0.9) anti-epileptic drugs at the first clinic visit. A total of 17 (34.0%) patients were referred to the surgical team and 11 (22.0%) underwent a neuro-surgical procedure. The average waiting time between visit 1 to surgical referral was 38.8 weeks (SD 25.1), and between visit 1 and the first post-operative visit was 55.8 weeks (SD 25.0).

Conclusion

The findings confirm international data showing significant waiting times between diagnosis of epilepsy and referral to specialist clinics for surgical assessment and highlight different approaches in each clinic in terms of visit numbers and recorded activities. A standardised pathway and data collection, including patient-reported outcome measures, would provide better evidence for whether promoting earlier referral and assessment for surgery improves the lives of this disease group.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1255-0) contains supplementary material, which is available to authorized users.

"Time is Brain"-How early should surgery be done in drug-resistant TLE?

OBJECTIVES

To explore the effect of duration of epilepsy and delay in surgery on seizure outcome in patients operated for drug-resistant temporal lobe epilepsy (TLE).

MATERIALS & METHODS

A total of 664 consecutive patients who underwent anterior temporal lobectomy (ATL) for TLE from 1995 to 2008 formed the study cohort. We divided them into two, one as seizure-free with or without antiepileptic drugs after ATL as "good outcome" (Engel class I a) and seizures of any type, any time after surgery as "poor outcome." The probability of seizure freedom/seizure recurrence based on the duration of epilepsy was compared using Kaplan-Meier curves, univariate Cox regression survival analysis, and multivariate Cox proportional hazards regression model.

RESULTS

A total of 136 children and 528 adults underwent ATL during this period. Mean duration of epilepsy pre-ATL was 17.1 + 9.4 years. At mean follow-up of 8.5 years, 331 patients (49.8%) had good outcome and 333 (50.2%) had poor outcome. The hazard of seizure recurrence linearly increased with duration of epilepsy pre-ATL, from 1.5 (duration of epilepsy, 5-10 years) to 1.9 (duration of epilepsy, 10-15 years) to 2 (duration of epilepsy over 15 years). In addition, encephalitis as antecedent, bilateral mesial temporal sclerosis in MRI, normal histopathology, and spikes in postoperative EEG at 3 months and 1 year predicted poor seizure outcome.

CONCLUSIONS

"Epilepsy duration" independently predicted both short- and long-term seizure outcome after surgery in TLE. "Lost years" translate into poor seizure outcome after ATL. Therefore, all cases of drug-resistant TLE should be referred to a surgical center at the earliest.

Predicting drug-resistant epilepsy - A machine learning approach based on administrative claims data

Patients with drug-resistant epilepsy (DRE) are at high risk of morbidity and mortality, yet their referral to specialist care is frequently delayed. The ability to identify patients at high risk of DRE at the time of treatment initiation, and to subsequently steer their treatment pathway toward more personalized interventions, has high clinical utility. Here, we aim to demonstrate the feasibility of developing algorithms for predicting DRE using machine learning methods. Longitudinal, intersected data sourced from US pharmacy, medical, and adjudicated hospital claims from 1,376,756 patients from 2006 to 2015 were analyzed; 292,892 met inclusion criteria for epilepsy, and 38,382 were classified as having DRE using a proxy measure for drug resistance. Patients were characterized using 1270 features reflecting demographics, comorbidities, medications, procedures, epilepsy status, and payer status. Data from 175,735 randomly selected patients were used to train three algorithms and from the remainder to assess the trained models' predictive power. A model with only age and sex was used as a benchmark. The best model, random forest, achieved an area under the receiver operating characteristic curve (95% confidence interval [CI]) of 0.764 (0.759, 0.770), compared with 0.657 (0.651, 0.663) for the benchmark model. Moreover, predicted probabilities for DRE were well-calibrated with the observed frequencies in the data. The model predicted drug resistance approximately 2 years before patients in the test dataset had failed two antiepileptic drugs (AEDs). Machine learning models constructed using claims data predicted which patients are likely to fail ≥3 AEDs and are at risk of developing DRE at the time of the first AED prescription. The use of such models can ensure that patients with predicted DRE receive specialist care with potentially more aggressive therapeutic interventions from diagnosis, to help reduce the serious sequelae of DRE.

De novo temporal intermittent rhythmic delta activity after laser interstitial thermal therapy for mesial temporal lobe epilepsy predicts poor seizure outcome

OBJECTIVE

To evaluate EEG abnormalities, particularly development of temporal intermittent rhythmic delta activity (TIRDA) after laser interstitial thermal therapy (LITT) and assess the role of further surgery after LITT.

METHODS

We retrospectively identified consecutive cases of LITT for the prevalence of post-operative TIRDA. We assessed baseline demographics, clinical variables including age of seizure onset, age at surgery, pre-operative and post-operative EEG changes.

RESULTS

40 patients underwent LITT for drug-resistant temporal lobe epilepsy (TLE), 29 met inclusion criteria. Median duration of follow-up was 15 months. Ten patients had post-LITT ipsilateral TIRDA, another two demonstrated post-operative TIRDA but they occurred contralateral to the side of ablation. None of the patients with TIRDA on their post-LITT EEG became seizure-free. Six out of 29 patients (21%) eventually required anterior temporal lobectomy (ATL), and of those 6 patients 4 (66%) had evidence of TIRDA on their post-LITT follow up EEG. The sensitivity and specificity of post-LITT TIRDA in predicting surgical failure was 57.14% and 100% respectively.

CONCLUSIONS

Post-LITT TIRDA may serve as a biomarker to predict unsuccessful seizure outcome following LITT and be an early indicator for ATL.

SIGNIFICANCE

The presence of TIRDA following LITT should prompt early consideration for reoperation.

Effects of Low Intensity Focused Ultrasound on Liposomes Containing Channel proteins

The ability to reversibly and non-invasively modulate region-specific brain activity in vivo suggests Low Intensity Focused Ultrasound (LIFU) as potential therapeutics for neurological dysfunctions such as epilepsy and Parkinson's disease. While in vivo studies provide evidence of the bioeffects of LIFU on neuronal activity, they merely hint at potential mechanisms but do not fully explain how this technology achieves these effects. One potential hypothesis is that LIFU produces local membrane depolarization by mechanically perturbing the neuronal cell membrane, or activating channels or other proteins embedded in the membrane. Proteins that sense mechanical perturbations of the membrane, such as those gated by membrane tension, are prime candidates for activating in response to LIFU and thus leading to the neurological responses that have been measured. Here we use the bacterial mechanosensitive channel MscL, which has been purified and reconstituted in liposomes, to determine how LIFU may affect the activation of this membrane-tension gated channel. Two bacterial voltage-gated channels, KvAP and NaK2K F92A channels were also studied. Surprisingly, the results suggest that ultrasound modulation and membrane perturbation does not induce channel gating, but rather induces pore formation at the membrane protein-lipid interface. However, in vesicles with high MscL mechanosensitive channel concentrations, apparent decreases in pore formation are observed, suggesting that this membrane-tension-sensitive protein may serve to increase the elasticity of the membrane, presumably because of expansion of the channel in the plane of the membrane independent of channel gating.

Post-operative nonketotic hyperglycemic induced focal motor status epilepticus related to treatment with corticosteroids following standard anterior temporal lobectomy

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Complications from standard ATL are uncommon and the use of post-operative corticosteroids may reduce complications.

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Following standard ATL, FMSE was present after treatment with corticosteroids that resolved after blood sugar control.

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After epilepsy surgery, corticosteroids should be used cautiously in people with comorbid diabetes mellitus.

Putting it all together: Options for intractable epilepsy: An updated algorithm on the use of epilepsy surgery and neurostimulation

For drug-resistant epilepsy, nonpharmacologic treatments should be considered early rather than late. Of the nondrug treatments, only resective surgery can be curative. Neurostimulation is palliative, i.e., not expected to achieve a seizure-free outcome. While resective surgery is the goal, other options are necessary because the majority of patients with drug-resistant epilepsy are not surgical candidates, and others have seizures that fail to improve with surgery or have only partial improvement but not seizure freedom. Neurostimulation modalities include vagus nerve stimulation (VNS), responsive neurostimulation (RNS), and deep brain stimulation (DBS), each with its own advantages, disadvantages, and side effects. In most scenarios, determined by noninvasive evaluation, especially EEG and MRI, several strategies are reasonable. For focal epilepsies, the choices are between resective surgery, with or without intracranial EEG, and all three modalities of neurostimulation. In situations where resective surgery is likely to result in seizure freedom, such as mesiotemporal lobe epilepsy or lesional focal epilepsy, resection (standard, laser, or radiofrequency) is preferred. For difficult cases like extratemporal nonlesional epilepsies, neurostimulation offers a less invasive option than resective surgery. For generalized and multifocal epilepsies, VNS is an option, RNS is not, and DBS has only limited evidence. "This article is part of the Supplement issue Neurostimulation for Epilepsy."

Surgical strategy for temporal lobe epilepsy with dual pathology and incomplete evidence from EEG and neuroimaging

Coexistence of hippocampal sclerosis (HS) and a temporal neocortical lesion, including focal cortical dysplasia, vascular malformations or benign primary brain tumors, is defined as dual pathology. In the majority of cases, the complete evidence based on electroencephalogram (EEG) and magnetic resonance imaging (MRI) for each of the dual pathological lesions is difficult to obtain. As a result, patients with dual pathology are poor surgical candidates due to potential incomplete resection of the epileptogenic zone. The current study retrospectively reviewed 24 patients with potential dual pathology and incomplete EEG and MRI evidence, aiming to provide novel surgical strategies. The results revealed a significantly worse seizure-free outcome for patients with incomplete EEG and MRI data compared with patients who received a clear diagnosis of dual pathology based on complete test results (11.1 vs. 60.0%; P<0.05). Notably, satisfying surgical (seizure-free) outcomes were still achieved in 60% of patients with unclear EEGs to locate the onset zone and clear MRI scans identifying the sclerotic hippocampus and nearby neocortical lesions, which could be resected together. In patients with multiple epileptogenic onsets or with widespread epileptic discharges, the hippocampus should be spared from resection due to concern for potential postsurgical mood or memory disorders. In conclusion, patients with resection of the sclerotic hippocampus and neocortical lesion had improved seizure-free outcomes compared with patients who received individual lesion resection. The current study aimed to provide a novel surgical strategy for neurosurgeons treating epileptic patients with dual pathology.

Personalized prediction model for seizure-free epilepsy with levetiracetam therapy: a retrospective data analysis using support vector machine

AIMS

To predict the probability of a seizure-free (SF) state in patients with epilepsy (PWEs) after treatment with levetiracetam and to identify the clinical and electroencephalographic (EEG) factors that affect outcomes.

METHODS

Retrospective analysis of PWEs treated with levetiracetam for 3 years identified 22 patients who were SF and 24 who were not. Before starting levetiracetam, 11 clinical factors and four EEG features (sample entropy of α, β, θ, δ) were identified. Overall, 80% of each the two groups were chosen to establish a support vector machine (SVM) model with 5-fold cross-validation, hold-out validation and jack-knife validation. The other 20% were used to predict the efficacy of levetiracetam. The mean impact value (MIV) algorithm was used to rank the relativity between factors and outcomes.

RESULTS

Compared with SF patients, not SF patients displayed a specific decrease in EEG sample entropy in α band from the F4 channel, β band from Fp2 and F8 channels, θ band from C3 channel (P < 0.05). The SVM model based on the clinical and EEG features yielded 72.2% accuracy of 5-fold cross-validation, 75.0% accuracy of jack-knife validation, 67.7% accuracy of hold-out validation in the training set and had a high prediction accuracy of 90% in test set (sensitivity was 100%, area under the receiver operating characteristic curve was 0.96). The feature of β band from Fp2 weighs heavily in the prediction model according to the mean impact value algorithm.

CONCLUSIONS

The efficacy of levetiracetam on newly diagnosed PWEs could be predicted using an SVM model, which could guide antiepileptic drug selection.

Unusual ictal propagation patterns suggesting poor prognosis after temporal lobe epilepsy surgery: Switch of lateralization and bilateral asynchrony

OBJECTIVE

The objective of this study was to investigate unusual ictal propagation patterns in patients with drug-resistant temporal lobe epilepsy (TLE) and reveal their electrophysiological, neuroimaging, and prognostic properties after surgery.

METHODS

Among 248 patients with TLE who underwent scalp video-electroencephalographic (EEG) monitoring, 24 patients with 'switch of lateralization' or 'bilateral asynchrony' in at least one of their seizures (9.3%) were analyzed retrospectively. The postoperative outcome was determined in 16 patients who had undergone epilepsy surgery.

RESULTS

All but 5 of the included patients had hippocampal sclerosis (HS) as their magnetic resonance imaging (MRI) findings. Twelve out of 16 patients (75%) who had surgery were seizure-free for at least 1 year. Nine out of 12 patients (75%) with good outcome had unilateral interictal EEG discharges in temporal regions whereas 3 out of 4 patients with poor outcome had bilateral temporal interictal spiking (p = 0.018).

CONCLUSION

Unusual ictal propagation patterns are not always related to poor prognosis after surgery in patients with TLE. Patients with unilateral interictal spiking in the temporal region tend to have good outcome despite these unusual patterns. These patterns can also be seen in patients with TLE with other etiologies besides the well-known HS in MRI.

The Insula in Temporal Plus Epilepsy

Temporal lobe epilepsy (TLE) surgery is the most common type of surgical treatment offered to patients with drug-resistant focal seizures. However, the proportion of patients experiencing long-term freedom from seizures after TLE surgery remains suboptimal. Temporal plus epilepsy, which is characterized by a primary temporal epileptogenic zone extending to neighboring regions, has been demonstrated to be a major predictor of TLE surgery failures. In the context of the temporoperisylvian epilepsies, i.e., the most common type of temporal plus epilepsy, a possible role of the insula has often been hypothesized. As this area is buried deep within the lateral sulcus, the use of invasive recordings is often required. Identifying patients with temporal plus seizures is a relevant issue, as they appear to have a worse postsurgical seizure outcome compared with patients with "pure" temporal lobe seizures. Owing to these prognostic implications, it becomes important to identify, among patients suffering from "atypical" nonlesional TLEs, those who should undergo invasive investigations, in particular to explore the insula. In fact, only a primary involvement of the insula in the epileptogenic network may require to include this area in the resection to achieve seizure freedom. Using modern neurosurgical techniques, insular epilepsy surgery has proved to be safe and beneficial, making the "true" role of the insula in TLE surgery failures more relevant to understand. Further studies are needed to evaluate the efficacy of multilobar resections in patients with temporal plus epilepsy, in particular, when eloquent or difficult to access areas such as insula are suspected to be involved.

Voxel-based automated detection of focal cortical dysplasia lesions using diffusion tensor imaging and T2-weighted MRI data

The aim of this study was to automatically detect focal cortical dysplasia (FCD) lesions in patients with extratemporal lobe epilepsy by relying on diffusion tensor imaging (DTI) and T2-weighted magnetic resonance imaging (MRI) data. We implemented an automated classifier using voxel-based multimodal features to identify gray and white matter abnormalities of FCD in patient cohorts. In addition to the commonly used T2-weighted image intensity feature, DTI-based features were also utilized. A Gaussian processes for machine learning (GPML) classifier was tested on 12 patients with FCD (8 with histologically confirmed FCD) scanned at 1.5 T and cross-validated using a leave-one-out strategy. Moreover, we compared the multimodal GPML paradigm's performance with that of single modal GPML and classical support vector machine (SVM). Our results demonstrated that the GPML performance on DTI-based features (mean AUC = 0.63) matches with the GPML performance on T2-weighted image intensity feature (mean AUC = 0.64). More promisingly, GPML yielded significantly improved performance (mean AUC = 0.76) when applying DTI-based features to multimodal paradigm. Based on the results, it can also be clearly stated that the proposed GPML strategy performed better and is robust to unbalanced dataset contrary to SVM that performed poorly (AUC = 0.69). Therefore, the GPML paradigm using multimodal MRI data containing DTI modality has promising result towards detection of the FCD lesions and provides an effective direction for future researches.

Increased nationwide use of stereoencephalography for intracranial epilepsy electroencephalography recordings

Intracranial electroencephalography (iEEG) can be performed using minimally invasive stereo-electroencephalography (SEEG) or by implanting subdural electrodes via a craniotomy or multiple burr holes. There is anecdotal evidence that SEEG is becoming more common in the United States, though this has yet to be quantified. To address this question, all SEEG and burr hole/craniotomy subdural iEEG procedures were extracted from the Centers for Medicare and Medicaid Services Part B data files for the years 2000-2016. National trends were compared over time. In 2016, SEEG became the most frequently performed intracranial monitoring procedure in the Medicare population, increasing from 28.8% of total cases in 2000 to 43.1% in 2016 (p = 0.02). The proportion of strip electrode cases (through burr holes) significantly declined, while the frequency of craniotomies for subdural grid placement did not significantly change. These data are consistent with a nationwide increase in the utilization of SEEG with a concomitant decline in burr hole placement of subdural strip electrodes in the United States. The factors driving these changes are unknown, but are likely due in part to the desire for minimally invasive surgical options.

Hemispherotomy and Functional Hemispherectomy: Indications and Outcomes

Hemispherectomy constitutes an established surgical method in the management of patients with medically intractable epilepsy secondary to severe unilateral hemisphere damage. As opposed to focal resections, in hemispherotomies, the entire hemisphere is disconnected from the remaining nervous system, including the functional regions and fibers. Despite this, hemispherotomy is recommended for certain indications, and has good functional and epilepsy outcomes. Here we describe the indications, epilepsy outcomes, and surgical techniques for several hemispheric surgeries.

Accuracy of an online tool to assess appropriateness for an epilepsy surgery evaluation-A population-based Swedish study

OBJECTIVE

The Canadian Appropriateness of Epilepsy Surgery (CASES) tool was developed to help physicians identify patients who should be referred for an epilepsy surgery evaluation. The aim of this study was to determine the accuracy of this tool using a population-based cohort registry (the Swedish National Epilepsy Surgery Register) of patients who underwent epilepsy surgery between 1990 and 2012.

METHODS

Overall, 1044 patients met eligibility criteria for the study and were deemed to be surgical candidates by epilepsy experts. Demographic and epilepsy related characteristics were examined and summarized using descriptive statistics. A CASES appropriateness score was calculated for each of these patients. Chi squared analyses or fisher's exact tests were used to determine if there were any relationships between demographic and epilepsy related characteristics not captured in the tool and appropriateness scores.

RESULTS

The mean appropriateness score was 8.6 and 985 (Sensitivity: 94.35%; 95% CI, 92.77%-95.60%) patients were appropriate, 46 (4.41%; 95% CI, 3.31%-5.84%) were uncertain, and 13 (1.25%; 95% CI, 0.72%-2.13%) were inappropriate for an epilepsy surgery evaluation. The mean necessity score, which was only calculated for the 985 appropriate patients, was 8.7. All 13 inappropriate patients had tried less than two anti-epileptic drugs (AEDs). In addition, age at onset of epilepsy and age at epilepsy surgery were both significantly associated with appropriateness score.

CONCLUSIONS

These results demonstrate that the CASES tool is highly sensitive as it designated 94.3% of epilepsy surgery patients as appropriate for an epilepsy surgery evaluation. All of those classified as inappropriate were not drug resistant, as they had not yet tried two AEDs.

European trends in epilepsy surgery

OBJECTIVE

Resective surgery is effective in treating drug-resistant focal epilepsy, but it remains unclear whether improved diagnostics influence postsurgical outcomes. Here, we compared practice and outcomes over 2 periods 15 years apart.

METHODS

Sixteen European centers retrospectively identified 2 cohorts of children and adults who underwent epilepsy surgery in the period of 1997 to 1998 (n = 562) or 2012 to 2013 (n = 736). Data collected included patient (sex, age) and disease (duration, localization and diagnosis) characteristics, type of surgery, histopathology, Engel postsurgical outcome, and complications, as well as imaging and electrophysiologic tests performed for each case. Postsurgical outcome predictors were included in a multivariate logistic regression to assess the strength of date of surgery as an independent predictor.

RESULTS

Over time, the number of operated cases per center increased from a median of 31 to 50 per 2-year period (p = 0.02). Mean disease duration at surgery decreased by 5.2 years (p < 0.001). Overall seizure freedom (Engel class 1) increased from 66.7% to 70.9% (adjusted p = 0.04), despite an increase in complex surgeries (extratemporal and/or MRI negative). Surgeries performed during the later period were 1.34 times (adjusted odds ratio; 95% confidence interval 1.02-1.77) more likely to yield a favorable outcome (Engel class I) than earlier surgeries, and improvement was more marked in extratemporal and MRI-negative temporal epilepsy. The rate of persistent neurologic complications remained stable (4.6%-5.3%, p = 0.7).

CONCLUSION

Improvements in European epilepsy surgery over time are modest but significant, including higher surgical volume, shorter disease duration, and improved postsurgical seizure outcomes. Early referral for evaluation is required to continue on this encouraging trend.

Radiosurgery versus open surgery for mesial temporal lobe epilepsy: The randomized, controlled ROSE trial

OBJECTIVE

To compare stereotactic radiosurgery (SRS) versus anterior temporal lobectomy (ATL) for patients with pharmacoresistant unilateral mesial temporal lobe epilepsy (MTLE).

METHODS

This randomized, single-blinded, controlled trial recruited adults eligible for open surgery among 14 centers in the USA, UK, and India. Treatment was either SRS at 24 Gy to the 50% isodose targeting mesial structures, or standardized ATL. Outcomes were seizure remission (absence of disabling seizures between 25 and 36 months), verbal memory (VM), and quality of life (QOL) at 36-month follow-up.

RESULTS

A total of 58 patients (31 in SRS, 27 in ATL) were treated. Sixteen (52%) SRS and 21 (78%) ATL patients achieved seizure remission (difference between ATL and SRS = 26%, upper 1-sided 95% confidence interval = 46%, P value at the 15% noninferiority margin = .82). Mean VM changes from baseline for 21 English-speaking, dominant-hemisphere patients did not differ between groups; consistent worsening occurred in 36% of SRS and 57% of ATL patients. QOL improved with seizure remission. Adverse events were anticipated cerebral edema and related symptoms for some SRS patients, and cerebritis, subdural hematoma, and others for ATL patients.

SIGNIFICANCE

These data suggest that ATL has an advantage over SRS in terms of proportion of seizure remission, and both SRS and ATL appear to have effectiveness and reasonable safety as treatments for MTLE. SRS is an alternative to ATL for patients with contraindications for or with reluctance to undergo open surgery.

Marginal decision-making in the treatment of refractory epilepsy

OBJECTIVE

Epilepsy surgery is one of the most effective treatments in modern medicine. Yet, it remains largely under-utilized, in spite of its proven efficacy. The referrals for epilepsy surgery are often delayed until it is too late to prevent the detrimental psychosocial effects of refractory seizures. The reluctance towards epilepsy surgery is influenced by the perceived risks of the procedure by practitioners and patients. This review discusses how, in general decision-making processes, one faces a natural tendency towards emphasizing the risks of the most immediate and operational decision (surgery), at times without contrasting these risks with the alternative (uncontrolled epilepsy).

METHODS

In the field of economics, this bias is well recognized and can be overcome through marginal analysis, formally defined as focusing on incremental changes as opposed to absolute levels.

RESULTS

Regarding epilepsy surgery, the risks and benefits of surgery are considered separately from the risks of uncontrolled epilepsy. For instance, even though surgery carries an ∼0.1-0.5% risk of perioperative mortality, the chance of sudden unexpected death with refractory epilepsy can be as high as 0.6-0.9% per year. It is suggested that the inadequate way of phrasing clinical questions can be a crucial contributing factor for the under-utilization of epilepsy surgery.

SIGNIFICANCE

It is proposed that examining decision-making for epilepsy surgery in the context of marginal analysis may enable providers and patients to make more accurate informed decisions.

Epidemiologist's view: Addressing the epilepsy surgery treatment gap with minimally-invasive techniques

Despite the fact that epilepsy surgery is both safe and effective, a considerable "surgical treatment gap" remains in that most persons who are eligible for surgery do not receive it. It has been argued that epilepsy surgery is one of the most underutilized of all accepted medical treatments in the world. In this article, we review the epidemiology of the epilepsy surgery treatment gap, and consider the role minimally-invasive epilepsy surgery may play in reducing this gap.

Epilepsy and Neuromodulation-Randomized Controlled Trials

Neuromodulation is a treatment strategy that is increasingly being utilized in those suffering from drug-resistant epilepsy who are not appropriate for resective surgery. The number of double-blinded RCTs demonstrating the efficacy of neurostimulation in persons with epilepsy is increasing. Although reductions in seizure frequency is common in these trials, obtaining seizure freedom is rare. Invasive neuromodulation procedures (DBS, VNS, and RNS) have been approved as therapeutic measures. However, further investigations are necessary to delineate effective targeting, minimize side effects that are related to chronic implantation and to improve the cost effectiveness of these devices. The RCTs of non-invasive modes of neuromodulation whilst showing much promise (tDCS, eTNS, rTMS), require larger powered studies as well as studies that focus at better targeting techniques. We provide a review of double-blinded randomized clinical trials that have been conducted for neuromodulation in epilepsy.

Getting the best outcomes from epilepsy surgery

Neurosurgery is an underutilized treatment that can potentially cure drug‐refractory epilepsy. Careful, multidisciplinary presurgical evaluation is vital for selecting patients and to ensure optimal outcomes. Advances in neuroimaging have improved diagnosis and guided surgical intervention. Invasive electroencephalography allows the evaluation of complex patients who would otherwise not be candidates for neurosurgery. We review the current state of the assessment and selection of patients and consider established and novel surgical procedures and associated outcome data. We aim to dispel myths that may inhibit physicians from referring and patients from considering neurosurgical intervention for drug‐refractory focal epilepsies. Ann Neurol 2018;83:676–690

Designing Patient-Specific Optimal Neurostimulation Patterns for Seizure Suppression

Neurostimulation is a promising therapy for abating epileptic seizures. However, it is extremely difficult to identify optimal stimulation patterns experimentally. In this study, human recordings are used to develop a functional 24 neuron network statistical model of hippocampal connectivity and dynamics. Spontaneous seizure-like activity is induced in silico in this reconstructed neuronal network. The network is then used as a testbed to design and validate a wide range of neurostimulation patterns. Commonly used periodic trains were not able to permanently abate seizures at any frequency. A simulated annealing global optimization algorithm was then used to identify an optimal stimulation pattern, which successfully abated 92% of seizures. Finally, in a fully responsive, or closed-loop, neurostimulation paradigm, the optimal stimulation successfully prevented the network from entering the seizure state. We propose that the framework presented here for algorithmically identifying patient-specific neurostimulation patterns can greatly increase the efficacy of neurostimulation devices for seizures.

A modern epilepsy surgery treatment algorithm: Incorporating traditional and emerging technologies

Epilepsy surgery has seen numerous technological advances in both diagnostic and therapeutic procedures in recent years. This has increased the number of patients who may be candidates for intervention and potential improvement in quality of life. However, the expansion of the field also necessitates a broader understanding of how to incorporate both traditional and emerging technologies into the care provided at comprehensive epilepsy centers. This review summarizes both old and new surgical procedures in epilepsy using an example algorithm. While treatment algorithms are inherently oversimplified, incomplete, and reflect personal bias, they provide a general framework that can be customized to each center and each patient, incorporating differences in provider opinion, patient preference, and the institutional availability of technologies. For instance, the use of minimally invasive stereotactic electroencephalography (SEEG) has increased dramatically over the past decade, but many cases still benefit from invasive recordings using subdural grids. Furthermore, although surgical resection remains the gold-standard treatment for focal mesial temporal or neocortical epilepsy, ablative procedures such as laser interstitial thermal therapy (LITT) or stereotactic radiosurgery (SRS) may be appropriate and avoid craniotomy in many cases. Furthermore, while palliative surgical procedures were once limited to disconnection surgeries, several neurostimulation treatments are now available to treat eloquent cortical, bitemporal, and even multifocal or generalized epilepsy syndromes. An updated perspective in epilepsy surgery will help guide surgical decision making and lay the groundwork for data collection needed in future studies and trials.

Surgical Considerations of Intractable Mesial Temporal Lobe Epilepsy

Surgery of temporal lobe epilepsy is the best opportunity for seizure freedom in medically intractable patients. The surgical approach has evolved to recognize the paramount importance of the mesial temporal structures in the majority of patients with temporal lobe epilepsy who have a seizure origin in the mesial temporal structures. For those individuals with medically intractable mesial temporal lobe epilepsy, a selective amygdalohippocampectomy surgery can be done that provides an excellent opportunity for seizure freedom and limits the resection to temporal lobe structures primarily involved in seizure genesis.

Intense olfactory stimulation blocks seizures in an experimental model of epilepsy

There are reports of patients whose epileptic seizures are prevented by means of olfactory stimulation. Similar findings were described in animal models of epilepsy, such as the electrical kindling of amygdala, where olfactory stimulation with toluene (TOL) suppressed seizures in most rats, even when the stimuli were 20% above the threshold to evoke seizures in already kindled animals. The Wistar Audiogenic Rat (WAR) strain is a model of tonic-clonic seizures induced by acute acoustic stimulation, although it also expresses limbic seizures when repeated acoustic stimulation occurs - a process known as audiogenic kindling (AK). The aim of this study was to evaluate whether or not the olfactory stimulation with TOL would interfere on the behavioral expression of brainstem (acute) and limbic (chronic) seizures in the WAR strain. For this, animals were exposed to TOL or saline (SAL) and subsequently exposed to acoustic stimulation in two conditions that generated: I) acute audiogenic seizures (only one acoustic stimulus, without previous seizure experience before of the odor test) and II) after AK (20 acoustic stimuli [2 daily] before of the protocol test). We observed a decrease in the seizure severity index of animals exposed only to TOL in both conditions, with TOL presented 20s before the acoustic stimulation in both protocols. These findings were confirmed by behavioral sequential analysis (neuroethology), which clearly indicated an exacerbation of clusters of specific behaviors such as exploration and grooming (self-cleaning), as well as significant decrease in the expression of brainstem and limbic seizures in response to TOL. Thus, these data demonstrate that TOL, a strong olfactory stimulus, has anticonvulsant properties, detected by the decrease of acute and AK seizures in WARs.

Efficacy of the Danish epilepsy surgery programme

OBJECTIVE

Despite optimal medical treatment, approximately one-third of patients with epilepsy continue to have seizures. Epilepsy surgery is widely accepted as a therapeutic option in the selected subset of patients with drug-resistant focal epilepsy. Here, we report the results of the Danish epilepsy surgery programme from 2009 to 2014.

MATERIAL AND METHODS

A total of 169 consecutive patients, operated at Rigshospitalet, were included. Information was gathered from digital patient records. Before 1-year follow-up, two patients were lost to follow-up and three were referred to new surgery.

RESULTS

The median years of drug resistance before operation were 11 years. At 1-year follow-up (n = 164), seizure outcomes were as follows: 65% Engel I (free from disabling seizures), 51% Engel IA (completely seizure free) and 9% Engel IV (no worthwhile improvement), and for patients operated in the medial temporal lobe (n = 114): 70% Engel I, 56% Engel IA, 5% Engel IV. The outcomes of the 53 patients needing intracranial EEG recording (ICR) were not significantly different from the patients only evaluated with surface EEG. None of the eight MRI-negative patients operated outside the medial temporal lobe after ICR were free of disabling seizures. 12% of MTLE patients developed de novo depression after epilepsy surgery despite good surgical outcome. Three patients required rehabilitation due to post-operative hemiplegia.

CONCLUSION

The outcomes of the Danish epilepsy surgery programme align with international results found in recent meta-analyses. Serious complications to epilepsy surgery are seldom. In accordance with international recommendations, Danish drug-resistant patients should be referred to epilepsy surgery evaluation at an earlier stage of the disease.

Trends in intracranial monitoring for pediatric medically intractable epilepsy

Objective

To retrospectively examine nationwide trends in intracranial monitoring (ICM) for pediatric medically intractable epilepsy (MIE) from 2000 to 2012.

Methods

The Healthcare Cost and Utilization Project Kids' Inpatient Database was analyzed to identify admissions with ICD-9-CM codes corresponding to MIE and ICM from 2000 to 2012, inclusive. Associations between independent variables and outcomes were tested using χ2 test or Fisher exact test. A multivariate logistic regression analysis of variables associated with ICM was completed using stepwise selection. The Cochran-Armitage test was used to test for trend of a variable over the study period.

Results

The number of ICM procedures increased over the study period; however, secondary to large increases in the number of MIE admissions, the rate of ICM declined from 5.39% in 2000 to 2.56% in 2012 (p < 0.001). Despite this decline, ICM increasingly resulted in resective epilepsy procedures. In 2000, only 45.18% of ICM cases led to resective epilepsy surgery, which increased to 75.83% by 2012 (p < 0.001). ICM complication rates were comparable to, if not lower than, standard resective surgery. Disparities in access to ICM exist, with African American individuals and those with Medicaid significantly less likely to undergo ICM.

Conclusion

In this nationwide characterization of pediatric ICM trends, we identified a slight, significant downward trend in the rate of utilization of ICM for MIE. This was secondary to substantial increases in the number of hospital admissions for MIE. Reasons for this large increase and why it has not led to increased rates of ICM warrant further investigation.

Drug-Resistant Epilepsy and Surgery

BACKGROUND

Epilepsy is a chronic brain disease that is caused by various factors and characterized by recurrent, episodic and temporary central nervous system dysfunction which results due to excessive discharge of brain neurons. In the past decades, despite the continuous development of antiepileptic drugs, there are still many patients with epilepsy progressing to drugresistant epilepsy. Currently, surgical treatment is one of important way to cure drug-resistant epilepsy.

METHODS

Data were collected from Web of Science, Medline, Pubmed, through searching of these keywords: "surgery" and "drug-resistant epilepsy".

RESULTS

An increasing number of studies have shown that surgery plays an important role in the treatment of drug-resistant epilepsy. Moreover, the comprehensive treatment mainly based on surgery can achieve the remission and even cure of drug-resistant epilepsy.

CONCLUSION

In this review, we discuss the pathogenesis of drug-resistant epilepsy and the comprehensive treatment mainly based on surgery; this review may provide a reference for the clinical treatment of drug-resistant epilepsy.

The impact of stereotactic laser ablation at a typical epilepsy center

PURPOSE

Stereotactic laser ablation (SLA) is a novel form of epilepsy surgery for patients with drug-resistant focal epilepsy. We evaluated one hundred consecutive surgeries performed for patients with epilepsy to address the impact of SLA on our therapeutic approach, as well as patient outcomes.

METHODS

A retrospective, single center analysis of the last one hundred neurosurgeries for epilepsy was performed from 2013 to 2015. Demographics, surgical procedures, and postoperative measures were assessed up to 5years to compare the effect of SLA on outcome. Confidence intervals (CI) and comparative tests of proportions compared outcomes for SLA and resective surgery. Procedural categorical comparison used Chi-square and Kaplan-Meier curves. Student t-test was utilized for single variables such as age at procedure and seizure onset.

RESULTS

One hundred surgeries for epilepsy yielded thirty-three SLAs and twenty-one resections with a mean of 21.7-month and 21.3-month follow-up, respectively. The temporal lobe was the most common target for SLA (92.6%) and resection (75%). A discrete lesion was present on brain magnetic resonance imaging (MRI) in 27/32 (84.4%) of SLA patients compared with 7/20 (35%) of resection patients with a normal MRI. Overall, 55-60% of patients became seizure-free (SF). Four of five patients with initial failure to SLA became SF with subsequent resection surgery. Complications were more frequent with resection although SF outcomes did not differ (Chi square; p=0.79). Stereotactic laser ablation patients were older than those with resections (47.0years vs. 35.4years, p=0.001). The mean length of hospitalization prior to discharge was shorter for SLA (1.18days) compared with open resection (3.43days; SD: 3.16 days) (p=0.0002).

CONCLUSION

We now use SLA as a first line therapy at our center in patients with lesional temporal lobe epilepsy (TLE) before resection. Seizure-free outcome with SLA and resection was similar but with a shorter length of stay. Long-term follow-up is recommended to determine sustained SF status from SLA.