Outcomes after hemispherectomy in adult patients with intractable epilepsy: institutional experience and systematic review of the literature

Predicting seizure outcomes and functional outcomes after hemispherotomy: are we any better?

INTRODUCTION

Present study attempted to analyze seizure freedom and detailed functional outcomes after functional hemispherotomy and utility of hemispherotomy outcome prediction scale (HOPS) scores in predicting outcomes.

METHODS

Patients who underwent functional hemispherotomy were analyzed for clinical presentation, neuroimaging, seizure outcomes, and functional outcomes.

RESULTS

A total of 76 procedures were performed on 69 patients. Mean age at the surgery was 8 ± 6.1 years. Fourteen patients were < 2 years. Age of onset epilepsy of the cohort was 2.0 ± 3.3 years. All had severe catastrophic epilepsy with multiple daily seizures. All patients had motor deficits with 36 (52%) patients had contralateral dysfunctional hand. Perinatal stroke (49%) was most common substrate followed by cortical malformations (21.7%). Eight patients had contralateral imaging abnormalities. Fifty-nine (86.76%) patients remained seizure free (Engle 1a) at 41 + -20.9 months. HOPS scores were available for 53 patients and lowest seizure outcome was 71% for HOPS score of 4. Lower HOPS scores predicted better seizure outcomes. Cortical malformations operated earlier than 2 years predicted poor seizure outcomes (66.6%). Positive functional outcomes are recorded in 80% of patients with 78% reporting improvement from the pre-surgical level. Five (7.2%) patients underwent shunt surgery. One mortality recorded.

CONCLUSIONS

Hemispherotomy has excellent seizure outcomes. Early surgery in cortical malformations appears to be predictor of poorer seizure outcomes. HOPS score is a good tool to predict the seizure outcomes. Hemispherotomy is perceived to improve the Cognitive and functional performance.

Functional hemispheric disconnection procedures for chronic epilepsy: history, indications, techniques, complications and current practice in Europe. A consensus statement on behalf of the EANS functional neurosurgery section

Introduction

The surgical procedure for severe, drug-resistant, unilateral hemispheric epilepsy is challenging. Over the last decades the surgical landscape for hemispheric disconnection procedures changed from anatomical hemispherectomy to functional hemispherotomy with a reduction of complications and stable good seizure outcome. Here, a task force of European epilepsy surgeons prepared, on behalf of the EANS Section for Functional Neurosurgery, a consensus statement on different aspects of the hemispheric disconnection procedure.

Research question

To determine history, indication, timing, techniques, complications and current practice in Europe for hemispheric disconnection procedures in drug-resistant epilepsy.

Material and methods

Relevant literature on the topic was collected by a literature search based on the PRISMA 2020 guidelines.

Results

A comprehensive overview on the historical development of hemispheric disconnection procedures for epilepsy is presented, while discussing indications, timing, surgical techniques and complications. Current practice for this procedure in European epilepsy surgery centers is provided. At present, our knowledge of long-term seizure outcomes primarily stems from open surgical disconnection procedures. Although minimal invasive surgical techniques in epilepsy are rapidly developing and reported in case reports or small case series, long-term seizure outcome remain uncertain and needs to be reported.

Discussion and conclusion

This is the first paper presenting a European consensus statement regarding history, indications, techniques and complications of hemispheric disconnection procedures for different causes of chronic, drug-resistant epilepsy. Furthermore, it serves as the pioneering document to report a comprehensive overview of the current surgical practices regarding this type of surgery employed in renowned epilepsy surgery centers across Europe.

Hemispheric epilepsy surgery for hemimegalencephaly: The UCLA experience

OBJECTIVES

Hemimegalencephaly (HME) is a rare congenital brain malformation presenting predominantly with drug-resistant epilepsy. Hemispheric disconnective surgery is the mainstay of treatment; however, little is known about how postoperative outcomes compare across techniques. Thus we present the largest single-center cohort of patients with HME who underwent epilepsy surgery and characterize outcomes.

METHODS

This observational study included patients with HME at University of California Los Angeles (UCLA) from 1984 to 2021. Patients were stratified by surgical intervention: anatomic hemispherectomy (AH), functional hemispherectomy (FH), or less-than-hemispheric resection (LTH). Seizure freedom, functional outcomes, and operative complications were compared across surgical approaches. Regression analysis identified clinical and intraoperative variables that predict seizure outcomes.

RESULTS

Of 56 patients, 43 (77%) underwent FH, 8 (14%) underwent AH, 2 (4%) underwent LTH, 1 (2%) underwent unknown hemispherectomy type, and 2 (4%) were managed non-operatively. At median last follow-up of 55 months (interquartile range [IQR] 20-92 months), 24 patients (49%) were seizure-free, 17 (30%) required cerebrospinal fluid (CSF) shunting for hydrocephalus, 9 of 43 (21%) had severe developmental delay, 8 of 38 (21%) were non-verbal, and 15 of 38 (39%) were non-ambulatory. There was one (2%) intraoperative mortality due to exsanguination earlier in this cohort. Of 12 patients (29%) requiring revision surgery, 6 (50%) were seizure-free postoperatively. AH, compared to FH, was not associated with statistically significant improved seizure freedom (hazard ratio [HR] = .48, p = .328), although initial AH trended toward greater odds of seizure freedom (75% vs 46%, p = .272). Younger age at seizure onset (HR = .29, p = .029), lack of epilepsia partialis continua (EPC) (HR = .30, p = .022), and no contralateral seizures on electroencephalography (EEG) (HR = .33, p = .039) independently predicted longer duration of seizure freedom.

SIGNIFICANCE

This study helps inform physicians and parents of children who are undergoing surgery for HME by demonstrating that earlier age at seizure onset, absence of EPC, and no contralateral EEG seizures were associated with longer postoperative seizure freedom. At our center, initial AH for HME may provide greater odds of seizure freedom with complications and functional outcomes comparable to those of FH.

Hemispherotomy Revised: A complication overview and a systematic review meta-analysis

Introduction

Hemispherectomy/hemispherotomy has been employed in the management of catastrophic epilepsy. However, initial reports on the associated mortality and morbidity raised several concerns regarding the technique's safety. Their actual, current incidence needs to be systematically examined to redefine hemispherotomy's exact role.

Research question

Our current study examined their incidence and evaluated the association of the various hemispherotomy surgical techniques with the reported complications.

Material & methods

A PRISMA-compliant systematic review and meta-analysis was performed. We searched PubMed, Scopus, and Web of Science until December 2022. Fixed- and random-effects models were employed. Egger's regression test was used for estimating the publication bias, while subgroup analysis was utilized for defining the role of the different hemispherotomy techniques.

Results

We retrieved a total of 37 studies. The overall procedure mortality was 5%, with a reported mortality of 7% for hemispherectomy and 3% for hemispherotomy. The reported mortality has decreased over the last 30 years from 32% to 2%. Among the observed post-operative complications aseptic meningitis and/or fever occurred in 33%. Hydrocephalus requiring a shunt insertion occurred in 16%. Hematoma evacuation was necessary in 8%, while subgaleal effusion in another 8%. Infections occurred in 11%. A novel post-operative cranial nerve deficit occurred in 11%, while blood transfusion was necessary in 28% of the cases.

Discussion and conclusion

Our current analysis demonstrated that the evolution from hemispherectomy to hemispherotomy along with neuroanesthesia advances, had a tremendous impact on the associated mortality and morbidity. Hemispherotomy constitutes a safe surgical procedure in the management of catastrophic epilepsies.

Drug-resistant epilepsy and mortality-Why and when do neuromodulation and epilepsy surgery reduce overall mortality

Patients with drug-resistant epilepsy have an increased mortality rate, with the majority of deaths being epilepsy related and 40% due to sudden unexpected death in epilepsy (SUDEP). The impact of epilepsy surgery on mortality has been investigated since the 1970s, with increased interest in this field during the past 15 years. We systematically reviewed studies investigating mortality rate in patients undergoing epilepsy surgery or neuromodulation therapies. The quality of available evidence proved heterogenous and often limited by significant methodological issues. Perioperative mortality following epilepsy surgery was found to be <1%. Meta-analysis of studies that directly compared patients who underwent surgery to those not operated following presurgical evaluation showed that the former have a two-fold lower risk of death and a three-fold lower risk of SUDEP compared to the latter (odds ratio [OR] 0.40, 95% confidence interval [CI]: 0.29-0.56; p < .0001 for overall mortality and OR 0.32, 95% CI: 0.18-0.57; p < .001 for SUDEP). Limited data are available regarding the risk of death and SUDEP in patients undergoing neuromodulation therapies, although some evidence indicates that vagus nerve stimulation might be associated with a lower risk of SUDEP. Several key questions remain to be addressed in future studies, considering the need to better inform patients about the long-term benefit-risk ratio of epilepsy surgery. Dedicated long-term prospective studies will thus be required to provide more personalized information on the impact of surgery and/or neuromodulation on the risk of death and SUDEP.

Midline Brain Shift After Hemispheric Surgery: Natural History, Clinical Significance, and Association With Cerebrospinal Fluid Diversion

BACKGROUND

Hemispherectomy and its modern variants are effective surgical treatments for medically intractable unihemispheric epilepsy. Although some complications such as posthemispherectomy hydrocephalus are well documented, midline brain shift (MLBS) after hemispheric surgery has only been described anecdotally and never formally studied.

OBJECTIVE

To assess the natural history and clinical relevance of MLBS and determine whether cerebrospinal fluid (CSF) shunting of the ipsilateral surgical cavity exacerbates MLBS posthemispheric surgery.

METHODS

A retrospective review of consecutive pediatric patients who underwent hemispheric surgery for intractable epilepsy and at least 6 months of follow-up at UCLA between 1994 and 2018 was performed. Patients were grouped by MLBS severity, shunt placement, valve type, and valve opening pressure (VOP). MLBS was evaluated using the paired samples t-test and analysis of covariance adjusting for follow-up time and baseline postoperative MLBS.

RESULTS

Seventy patients were analyzed, of which 23 (33%) required CSF shunt placement in the ipsilateral surgical cavity for posthemispherectomy hydrocephalus. MLBS increased between first and last follow-up for nonshunted (5.3 ± 4.9-9.7 ± 6.6 mm, P < .001) and shunted (6.6 ± 3.5-16.3 ± 9.4 mm, P < .001) patients. MLBS progression was greater in shunted patients (P = .001). Shunts with higher VOPs did not increase MLBS relative to nonshunted patients (P = .834), whereas MLBS increased with lower VOPs (P = .001). Severe MLBS was associated with debilitating headaches (P = .048).

CONCLUSION

Patients undergoing hemispheric surgery often develop postoperative MLBS, ie, exacerbated by CSF shunting of the ipsilateral surgical cavity, specifically when using lower VOP settings. MLBS exacerbation may be related to overshunting. Severe MLBS is associated with debilitating headaches.

Long term outcome of functional hemispherectomy for refractory epilepsy: Experience from a single center

BACKGROUND

Hemispherectomy has an established role as a treatment of last resort in patients with unilateral hemispheric lesions suffering from refractory epilepsy.

METHODS

Seven patients were evaluated at our Epilepsy Unit. We compared the seizure outcome at 6 months, 1, 2, 5 years post-surgery, as well as at end follow-up (mean 7.1 years) using Engel classification. Reduction of antiepileptic drugs (AEDs) was also assessed utilizing equal time frames.

RESULTS

The mean age of seizure onset was 5.4 years. Engel I was achieved in 5 patients at 6 months (71.4%). Engel at 1 year was predicted by the Engel at 6 months (p=0.013) with a similar number of patients being classified as Engel I outcome. Engel at 2 years was also predicted by Engel at 6 months and at 1 year (p=0.030). At end follow-up only 3 patients (42.9%) remained categorized as Engel I outcome. There was a trend toward a stability in Engel classification. All patients with developmental causes for their epilepsy experienced some deterioration of the surgical outcomes. Conversely, all patients with acquired causes were stable throughout follow-up. Seizure outcome at 6 months was worse in the patients who had post-op complications (p=0.044). Adult and pediatric populations did not differ significantly in any tested variable.

CONCLUSIONS

Hemispherectomy is a valuable resource for seizure control in properly selected patients. Engel patient's evolution could be predicted at 6 months interval. Hemispherectomy could be considered a useful attitude in difficult cases.

Long term outcome of functional hemispherectomy for refractory epilepsy: Experience from a single center

BACKGROUND

Hemispherectomy has an established role as a treatment of last resort in patients with unilateral hemispheric lesions suffering from refractory epilepsy.

METHODS

Seven patients were evaluated at our Epilepsy Unit. We compared the seizure outcome at 6 months, 1, 2, 5 years post-surgery, as well as at end follow-up (mean 7.1 years) using Engel classification. Reduction of antiepileptic drugs (AEDs) was also assessed utilizing equal time frames.

RESULTS

The mean age of seizure onset was 5.4 years. Engel I was achieved in 5 patients at 6 months (71.4%). Engel at 1 year was predicted by the Engel at 6 months (p=0.013) with a similar number of patients being classified as Engel I outcome. Engel at 2 years was also predicted by Engel at 6 months and at 1 year (p=0.030). At end follow-up only 3 patients (42.9%) remained categorized as Engel I outcome. There was a trend toward a stability in Engel classification. All patients with developmental causes for their epilepsy experienced some deterioration of the surgical outcomes. Conversely, all patients with acquired causes were stable throughout follow-up. Seizure outcome at 6 months was worse in the patients who had post-op complications (p=0.044). Adult and pediatric populations did not differ significantly in any tested variable.

CONCLUSIONS

Hemispherectomy is a valuable resource for seizure control in properly selected patients. Engel patient's evolution could be predicted at 6 months interval. Hemispherectomy could be considered a useful attitude in difficult cases.

Functional Hemispherectomy in Adults: All We Have to Sphere Is Sphere Itself

Hemispherectomy in Adults and Adolescents: Seizure and Functional Outcomes in 47 Patients

McGovern RA, NV Moosa A, Jehi L, Busch R, Ferguson L, Gupta A, et al. Epilepsia. 2019;60(12):2416-2427. http://doi.org/10.1111/epi.16378.

Objective:

To examine longitudinal seizure and functional outcomes after hemispherectomy in adults and adolescents.

Methods:

We reviewed 47 consecutive patients older than 16 years who underwent hemispherectomy between 1996 and 2016 at our center. Clinical, electroencephalographic (EEG), imaging, neuropsychological, surgical, and functional status data were analyzed.

Results:

Thirty-six patients were 18 years or older at surgery; 11 were aged between 16 and 18 years. Brain injury leading to hemispheric epilepsy occurred before 10 years of age in 41 (87%) patients. At a mean follow-up of 5.3 postoperative years (median = 2.9 years), 36 (77%) had Engel class I outcome. Longitudinal outcome analysis showed 84% seizure freedom (Engel IA) at 6 months, 76% at 2 years, and 76% at 5 years and beyond, with stable longitudinal outcomes up to 12 years from surgery. Multivariate analysis demonstrated that acute postoperative seizures and contralateral interictal spikes at 6-month follow-up EEG were associated with seizure recurrence. Patients who could walk unaided preoperatively and had no cerebral peduncle atrophy on brain magnetic resonance imaging were more likely to experience worsening of motor function postoperatively. Otherwise, postoperative ambulatory status and hand function were unchanged. Of the 19 patients who completed neuropsychological testing, 17 demonstrated stable or improved postoperative outcomes.

Significance:

Hemispherectomy in adults is a safe and effective procedure, with seizure freedom rates and functional outcome similar to those observed in children.

Hemispherectomy in adults and adolescents: Seizure and functional outcomes in 47 patients

OBJECTIVE

To examine longitudinal seizure and functional outcomes after hemispherectomy in adults and adolescents.

METHODS

We reviewed 47 consecutive patients older than 16 years who underwent hemispherectomy between 1996 and 2016 at our center. Clinical, electroencephalographic (EEG), imaging, neuropsychological, surgical, and functional status data were analyzed.

RESULTS

Thirty-six patients were 18 years or older at surgery; 11 were aged between 16 and 18 years. Brain injury leading to hemispheric epilepsy occurred before 10 years of age in 41 (87%) patients. At a mean follow-up of 5.3 postoperative years (median = 2.9 years), 36 (77%) had Engel class I outcome. Longitudinal outcome analysis showed 84% seizure freedom (Engel IA) at 6 months, 76% at 2 years, and 76% at 5 years and beyond, with stable longitudinal outcomes up to 12 years from surgery. Multivariate analysis demonstrated that acute postoperative seizures and contralateral interictal spikes at 6-month follow-up EEG were associated with seizure recurrence. Patients who could walk unaided preoperatively and had no cerebral peduncle atrophy on brain magnetic resonance imaging were more likely to experience worsening of motor function postoperatively. Otherwise, postoperative ambulatory status and hand function were unchanged. Of the 19 patients who completed neuropsychological testing, 17 demonstrated stable or improved postoperative outcomes.

SIGNIFICANCE

Hemispherectomy in adults is a safe and effective procedure, with seizure freedom rates and functional outcome similar to those observed in children.

The current and emerging therapeutic approaches in drug-resistant epilepsy management

Epilepsy is a neurologic disorder consisting of recurrent spontaneous seizures. Antiepileptic drugs administration is the most commonly used therapeutic strategy in the management of epilepsy. However, 20-30% of epilepsy patients have seizure episodes that are not controlled by these medicines (drug-resistant epilepsy). The management of drug-resistant epilepsy, especially in the children, is challenging and can cause economic and social problems, and lower the patients' quality of life, cognition, and mood. Several therapeutic approaches for drug-resistant epilepsy are available including surgical methods, neurostimulation treatments, and diet therapies which lead to diminishing the epileptic seizures. An increasing number of novel and potential therapeutic approaches such as gene therapy, gene editing, cell therapy, exosome therapy, and molecular network targeting have also been explored. The present study is aimed to review these current and emerging therapeutic approaches for drug-resistant epilepsy.

Influence of hippocampal low-frequency stimulation on GABAA R α1, ICER and BNDF expression level in brain tissues of amygdala-kindled drug-resistant temporal lobe epileptic rats

This study investigated the therapeutic effect of hippocampal low-frequency stimulation (Hip-LFS) and its influence on the type A γ-aminobutyric acid receptor α1 subunit (GABA_A R α1 subunit), inducible cAMP early repressor (ICER) and brain-derived neurotrophic factors (BNDF). The model of epilepsy was induced by chronic electrical stimulation in amygdala. Drug-resistant and drug-sensitive epileptic rats were selected by testing their seizure response to phenytoin and phenobarbital. The changes of GABA_A R α1 subunit, ICER and BDNF expression were detected via immunohistochemistry and western blot. The expression levels of ICER and BDNF were increased remarkably but the GABA_A R α1 subunit decreased significantly in the drug-resistant epileptic rats. However, the expression levels of ICER, BDNF were decreased and the expression of the GABA_A R α1 subunit increased significantly in the drug-resistant epileptic rats after two weeks of Hip-LFS. Meanwhile, the seizure degree was reduced and the electroencephalograms were improved. The present study demonstrated thatincreased ICER and BDNF might be associated with the development of drug-resistance. The effect of Hip-LFS in the treatment of drug-resistant epileptic rats might be associated with increasing the levels of the ICER and the BDNF.

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.