Vertical perithalamic hemispherotomy: A single-center experience in 40 pediatric patients with epilepsy

Trends and Most-Cited Articles on Hemispheric Surgery: A Bibliometric Analysis and Historical Review

INTRODUCTION

Hemispheric surgery is a multistep, highly effective, and radical surgical procedure in the treatment of drug-resistant epilepsy due to extensive unilateral hemispheric disease. The procedure ranges from a resective procedure (hemispherectomy) to disconnection (hemispherotomy) and has developed substantially over the last century from morbid to elegant, minimally invasive, and routinely practiced procedures. Bearing in mind the numerous articles that have been published on hemispherectomy and hemispherotomy, we aimed to highlight the top 100 cited and impactful articles to create familiarity with the topic. We anticipate that this will be a helpful guide for clinicians and academics navigating the literature on this subject.

METHODS

A Scopus title-based search on the top 100 most-cited articles on "hemispherectomy" and "hemispherotomy" was performed in September 2023 with no restrictions. The top 100 most-cited articles were then retrieved. The article title, first author, first author's specialty, country of origin, first author's institution at the time of publication, journal of publication, year of publication, citation count, and citations per year were collected. The Google Scholar database citation count for each paper was added for correlation and comprehensive coverage.

RESULTS

The top 100 most-cited articles were cited 92 times per paper on average. The publication dates ranged from 1949 to 2016. The most frequently cited article "Clinical outcomes of hemispherectomy for epilepsy in childhood and adolescence" with 307 citations was published by A.M. Devlin et al. (2003) in the journal Brain. The USA was the highest publishing country (41 articles). The highest-publishing journal was Neurology. The most prolific first authors were A. Smith, J. Schramm, and J. Villemure, each with four publications. The institution with the most contributions was McGill University and its affiliated Health Centers, with nine publications in total. Neurosurgery was the most common specialty among the first authors. Most of the included studies were cohort studies or case series.

CONCLUSION

We identified the top 100 cited articles on hemispherectomy and hemispherotomy using the Scopus database and supplemented our results with Google Scholar. We highlighted the most prominent authors, institutions, countries, journals, and study designs and illuminated the historical development of hemispherectomy and hemispherotomy procedures, in addition to landmark and currently trending papers.

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.

Modified Vertical Parasagittal Sub-Insular Hemispherotomy-Case Series and Technical Note

(1) Background: Hemispherotomy is the generally accepted treatment for hemispheric drug-resistant epilepsy (DRE). Lateral or vertical approaches are performed according to the surgeon's preference. Multiple technical variations have been proposed since Delalande first described his vertical technique. We propose a sub-insular variation of the vertical parasagittal hemispherotomy (VPH) and describe our case series of patients operated on using this procedure. (2) Methods: Data from a continuous series of patients with hemispheric DRE who were operated on by the senior author (CR) using the modified sub-insular VPH technique were analyzed retrospectively. Pre-operative demographic and epilepsy characteristics, functional outcome, and surgical complications were extracted from medical charts. (3) Results: Twenty-five patients were operated on between August 2008 and August 2023; 23 have at least 3 months of follow-up. Of this group, 20 (86.9%) patients are seizure-free. Only two patients developed postoperative hydrocephalus (8.7%). All patients who were able to walk autonomously preoperatively and 20 (86.9%) of those with follow-up were able to walk without assistance. A total of 17 (74%) patients were able to perform adapted social activities at the latest follow-up. (4) Conclusions: Modified sub-insular VPH is a successful surgical technique for hemispheric DRE with seizure freedom rates similar to the largest series reported in the literature. Compared to other series, patients who were operated on with our modified technique had a lower rate of postoperative hydrocephalus and excellent long-term motor and cognitive outcomes.

Comparison of Hemispheric Surgery Techniques for Pediatric Drug-Resistant Epilepsy: An Individual Patient Data Meta-analysis

BACKGROUND AND OBJECTIVES

Hemispheric surgery effectively treats unihemispheric pediatric drug-resistant epilepsy (DRE) by resecting and/or disconnecting the epileptic hemisphere. Modifications to the original anatomic hemispherectomy have generated multiple functionally equivalent, disconnective techniques for performing hemispheric surgery, termed functional hemispherotomy. While a myriad of hemispherotomy variants exist, all of them can be categorized according to the anatomic plane they are performed in, which includes vertical approaches at or near the interhemispheric fissure and lateral approaches at or near the Sylvian fissure. This meta-analysis of individual patient data (IPD) aimed to compare seizure outcomes and complications between the hemispherotomy approaches to better characterize their relative efficacy and safety in the modern neurosurgical treatment of pediatric DRE, given emerging evidence that outcomes may differ between them.

METHODS

CINAHL, Embase, PubMed, and Web of Science were searched from inception to September 9, 2020, for studies reporting IPD from pediatric patients with DRE who underwent hemispheric surgery. Outcomes of interest were seizure freedom at last follow-up, time-to-seizure recurrence, and complications including hydrocephalus, infection, and mortality. The χ2 test compared the frequency of seizure freedom and complications. Multivariable mixed-effects Cox regression controlling for predictors of seizure outcome was performed on propensity score-matched patients to compare time-to-seizure recurrence between approaches. Kaplan-Meier curves were made to visualize differences in time-to-seizure recurrence.

RESULTS

Fifty-five studies reporting on 686 unique pediatric patients treated with hemispheric surgery were included for meta-analysis. Among the hemispherotomy subgroup, vertical approaches resulted in a greater proportion of seizure free patients (81.2% vs 70.7%, p = 0.014) than lateral approaches. While there were no differences in complications, lateral hemispherotomy had higher rates of revision hemispheric surgery due to incomplete disconnection and/or recurrent seizures than vertical hemispherotomy (16.3% vs 1.2%, p < 0.001). After propensity score matching, vertical hemispherotomy approaches independently conferred longer time-to-seizure recurrence than lateral hemispherotomy approaches (hazard ratio 0.44, 95% CI 0.19-0.98).

DISCUSSION

Among functional hemispherotomy techniques, vertical hemispherotomy approaches confer more durable seizure freedom than lateral approaches without compromising safety. Future prospective studies are required to definitively determine whether vertical approaches are indeed superior and how it should influence clinical guidelines for performing hemispheric surgery.

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.

Seizure outcomes in children with Sturge-Weber syndrome undergoing epilepsy surgery: An individual participant data meta-analysis

BACKGROUND

A subpopulation of patients with Sturge-Weber syndrome (SWS) develop medically intractable epilepsy. There is a paucity of literature on preoperative factors that predict postoperative seizure outcomes in these patients. An individual participant data meta-analysis (IPDMA) was performed to discern preoperative variables associated with favorable seizure outcomes in pediatric SWS patients undergoing epilepsy surgery.

METHODS

PubMed, Cochrane, Web of Science, and Scopus were independently queried following PRISMA guidelines. Studies that reported seizure outcomes in individual pediatric SWS patients were selected. Preoperative demographic variables and disease characteristics were recorded and evaluated in a time-to-event fashion via Cox regression and Kaplan-Meier analysis with log-rank test.

RESULTS

A total of 18 studies with 108 patients were included for meta-analysis. Median age at seizure onset was 4.5 months, and 85 patients (78.7%) were seizure-free at last follow-up (median: 72 months). On multivariable Cox regression, no variables were independent predictors of post-operative seizure freedom duration, including the extent of hemispheric resection. There were also no differences in time-to-seizure recurrence on Kaplan-Meier analysis when comparing those treated with hemispheric surgery and those with less than hemispheric surgery (p = 0.52).

CONCLUSION

This IPDMA showed that both resective and hemispheric epilepsy surgery achieve favorable and comparable seizure outcomes in pediatric SWS patients. The best available evidence using IPD suggests that resective surgery may be an appropriate alternative to hemispheric epilepsy surgery in well-selected patients. Prospective multi-institutional studies with greater follow-up are warranted to further investigate predictors of seizure outcome in pediatric SWS patients.

Preliminary Experience Suggests the Addition of Choroid Plexus Cauterization to Functional Hemispherectomy May Reduce Posthemispherectomy Hydrocephalus

BACKGROUND

Cerebral hemispherectomy can effectively treat unihemispheric epilepsy. However, posthemispherectomy hydrocephalus (PHH), a serious life-long complication, remains prevalent, requiring careful considerations in technique selection and postoperative management. In 2016, we began incorporating open choroid plexus cauterization (CPC) into our institution's hemispherectomy procedure in an attempt to prevent PHH.

OBJECTIVE

To determine whether routine CPC prevented PHH without exacerbating hemispherectomy efficacy or safety.

METHODS

A retrospective review of consecutive patients who underwent hemispherectomy for intractable epilepsy between 2011 and 2021 was performed. Multivariate logistic regression was used to identify factors independently associated with PHH requiring cerebrospinal fluid (CSF) shunting.

RESULTS

Sixty-eight patients were included in this study, of whom 26 (38.2%) underwent CPC. Fewer patients required CSF shunting in the CPC group (7.7% vs 28.7%, P = .033) and no patients who underwent de novo hemispherectomy with CPC developed PHH. Both cohorts experienced seizure freedom (65.4% vs 59.5%, P = .634) and postoperative complications, including infection (3.8% vs 2.4%, P = .728), hemorrhage (0.0% vs 2.4%, P = .428), and revision hemispherectomy (19.2% vs 14.3%, P = .591) at similar rates. Patients without CPC had greater odds of developing PHH requiring CSF shunting (odds ratio = 8.36, P = .026). The number needed to treat with CPC to prevent an additional case of PHH was 4.8, suggesting high effectiveness.

CONCLUSION

Preventing PHH is critical. Our early experience demonstrated that routinely incorporating CPC into hemispherectomy effectively prevents PHH without causing additional complications, especially in first-time hemispherectomies. A multicenter randomized controlled trial with long-term follow-up is required to corroborate the findings of our single-institutional case series and determine whether greater adoption of this technique is justified.

[Lessons learnt from 101 hemispherotomies in children with symptomatic epilepsy. Part I: seizure outcome]

OBJECTIVE

To evaluate variables that may predict the outcome after hemispherotomy basing on a retrospective study of a large consecutive pediatric cohort of patients from a single institution.

MATERIAL AND METHODS

One hundred and one patients with refractory seizures and variable decline in development (n=78) underwent hemispherotomy (med. age - 43 months, med. epilepsy history - 30 months). Developmental pathology was the anatomical substrate of disorder in 42 patients, while the infantile post-stroke scarring and gliosis was its origin in the majority of 43 cases with acquired etiology. The progressive pathology (the Rasmussen encephalitis, Sturge-Weber angiomatosis and tuberous sclerosis) was the etiology in 16 children. Left-sided hemisphere was impaired in 54 cases; some contralateral anatomical and potentially epileptogenic MRI-abnormalities were noted also in «healthy» hemisphere in ¼ of all cases. Eight patients needed second surgery to complete sectioning of undercut commissural fibers. FU is known in 91 patients (med. - 1.5 years) and 73 of them were free of seizures (80.2%), but only 30 of 40 patients with FU > 2 years were still SF (75%). All but one of re-do hemispherotomies were successful. AED-treatment was discontinued in 46 cases and tapered in other 27 patients. Up to 90% of kids demonstrated some improvement in behavior and cognition.

RESULTS AND CONCLUSION

Developmental pathology, infantile spasms and younger age onset of seizures are negative predictors for achievement of SF-status (p<0.05). Neither bilateral epileptic EEG-signs, nor MRI-abnormalities in «healthy» hemisphere had any relation to outcome, but focal seizure onset was associated positively with further SF-status (p = 0.03). Kids with multiple lobe unilateral CD do somewhat worse than their counterparts with hemimegalencephaly and acquired etiology. Post-hemispherotomy hemiparesis (either new or worsening of already existed one) has no relation either to the age at surgery, or to the age onset (p = 0.41). Children with left-sided lesions were less successful in every neurodevelopmental domain except maintaining expressive language. Patients with relapse or persisting seizures have good chances to become SF by re-doing hemispherotomy and should be evaluated for the possibly incomplete hemispheric isolation.

Lateral versus vertical hemispheric disconnection for epilepsy: a systematic review and meta-analysis

OBJECTIVE

Lateral periinsular hemispherotomy (LPH) and vertical parasagittal hemispherotomy (VPH) are the most popular disconnective techniques for intractable epilepsies associated with unilateral hemispheric pathologies. The authors aimed to investigate possible differences in seizure outcome and complication rates between patients who underwent LPH and VPH.

METHODS

A comprehensive literature search of PubMed and Embase identified English-language articles published from database inception to December 2019 that reported series (minimum 12 patients with follow-up ≥ 12 months) on either LPH or VPH. Pooled rates of seizure freedom and complications (with a particular focus on hydrocephalus) were analyzed using meta-analysis to calculate both fixed and random effects. Heterogeneity (Cochran's Q test) and inconsistency (fraction of Q due to actual heterogeneity) were also calculated.

RESULTS

Twenty-five studies were included. Data from 825 patients were available for seizure outcome analysis (583 underwent LPH and 242 underwent VPH), and data from 692 patients were available for complication analysis (453 underwent LPH and 239 underwent VPH). No differences were found in the pooled rates of Engel class I seizure outcome between patients who underwent LPH (80.02% and 79.44% with fixed and random effects, respectively) and VPH (79.89% and 80.69% with fixed and random effects, respectively) (p = 0.953). No differences were observed in the pooled rates of shunted hydrocephalus between patients who underwent LPH (11.34% and 10.63% with fixed and random effects, respectively) and VPH (11.07% and 9.98% with fixed and random effects, respectively) (p = 0.898). Significant heterogeneity and moderate inconsistency were determined for hydrocephalus occurrence in patients who underwent both LPH and VPH.

CONCLUSIONS

LPH and VPH techniques present similar excellent seizure outcomes, with comparable and acceptable safety profiles.

Vertical parasagittal hemispherotomy: a case report of postoperative mesio-temporal seizures via amygdalofugal pathway

Vertical parasagittal hemispherotomy (VPH) is a well-established surgical treatment which is proposed for children with widespread unilateral onset of intractable epileptic seizures. VPH allows to disconnect from a vertical transventricular approach all white matter fibers of the hemisphere around a central core including the thalamus. We present the case of a girl who underwent VPH for hemimegalencephaly in early infancy. Postoperatively, she developed unexpected seizures of mesio-temporal origin. Stereo-EEG provided arguments for an amygdalar origin. High-resolution MRI with tractography confirmed the presence of the amygdalo-fugal pathway to be responsible of epileptic discharges propagation. She became seizure-free after temporal resection.

Comparison of the real-world effectiveness of vertical versus lateral functional hemispherotomy techniques for pediatric drug-resistant epilepsy: A post hoc analysis of the HOPS study

Objective

This study was undertaken to determine whether the vertical parasagittal approach or the lateral peri‐insular/peri‐Sylvian approach to hemispheric surgery is the superior technique in achieving long‐term seizure freedom.

Methods

We conducted a post hoc subgroup analysis of the HOPS (Hemispheric Surgery Outcome Prediction Scale) study, an international, multicenter, retrospective cohort study that identified predictors of seizure freedom through logistic regression modeling. Only patients undergoing vertical parasagittal, lateral peri‐insular/peri‐Sylvian, or lateral trans‐Sylvian hemispherotomy were included in this post hoc analysis. Differences in seizure freedom rates were assessed using a time‐to‐event method and calculated using the Kaplan–Meier survival method.

Results

Data for 672 participants across 23 centers were collected on the specific hemispherotomy approach. Of these, 72 (10.7%) underwent vertical parasagittal hemispherotomy and 600 (89.3%) underwent lateral peri‐insular/peri‐Sylvian or trans‐Sylvian hemispherotomy. Seizure freedom was obtained in 62.4% (95% confidence interval [CI] = 53.5%–70.2%) of the entire cohort at 10‐year follow‐up. Seizure freedom was 88.8% (95% CI = 78.9%–94.3%) at 1‐year follow‐up and persisted at 85.5% (95% CI = 74.7%–92.0%) across 5‐ and 10‐year follow‐up in the vertical subgroup. In contrast, seizure freedom decreased from 89.2% (95% CI = 86.3%–91.5%) at 1‐year to 72.1% (95% CI = 66.9%–76.7%) at 5‐year to 57.2% (95% CI = 46.6%–66.4%) at 10‐year follow‐up for the lateral subgroup. Log‐rank test found that vertical hemispherotomy was associated with durable seizure‐free progression compared to the lateral approach (p = .01). Patients undergoing the lateral hemispherotomy technique had a shorter time‐to‐seizure recurrence (hazard ratio = 2.56, 95% CI = 1.08–6.04, p = .03) and increased seizure recurrence odds (odds ratio = 3.67, 95% CI = 1.05–12.86, p = .04) compared to those undergoing the vertical hemispherotomy technique.

Significance

This pilot study demonstrated more durable seizure freedom of the vertical technique compared to lateral hemispherotomy techniques. Further studies, such as prospective expertise‐based observational studies or a randomized clinical trial, are required to determine whether a vertical approach to hemispheric surgery provides superior long‐term seizure outcomes.

Robotic thermocoagulative hemispherotomy: concept, feasibility, outcomes, and safety of a new "bloodless" technique

OBJECTIVE

The authors present a new "bloodless" technique for minimally invasive robotic thermocoagulative hemispherotomy (ROTCH). Such a method is being described in the literature for the first time.

METHODS

A robotic system was used to plan five sets of different trajectories: anterior disconnection, middle disconnection, posterior disconnection, corpus callosotomy, and temporal stem and amygdalar disconnection. A special technique, called the "X" technique, allowed planar disconnection. Registration was performed with surface landmarks (n = 5) and bone fiducials (n = 1). Coregistration with O-arm images was performed one or two times to confirm the trajectories (once for middle disconnection, and once for disconnection of the temporal stem and amygdala or body of the corpus callosum). Impedance measured before ablation allowed for minor adjustments. Radiofrequency ablation was performed at 75°C-80°C for 60 seconds. Surgical procedures were performed with multiple twist drills. After removal of the electrode, glue was used to prevent CSF leak, and a single stitch was applied. Follow-up CT and MRI were immediately performed.

RESULTS

The pathologies included Rasmussen's encephalitis (n = 2), hemispheric cortical dysplasia (n = 2), posttraumatic encephalomalacia (n = 1), and perinatal insult (n = 1). The mean ± SD (range) age was 6.7 ± 3.6 years (5 months to 10.2 years), and the right side was affected in 4 patients. The mean ± SD seizure frequency was 7.4 ± 5.6 seizures per day (1 patient had epilepsia partialis continua). The mean ± SD number of trajectories was 15.3 ± 2.5, and the mean ± SD number of lesions was 108 ± 25.8. The mean ± SD maximum numbers of trajectories and lesions required for middle disconnection were 7.1 ± 1.7 and 57.5 ± 18.4, respectively. All but 1 patient had class 1 outcomes according to the International League Against Epilepsy Outcome Scale at a mean ± SD (range) follow-up of 13.5 ± 1.6 (12-16) months; the remaining patient had a class 2 outcome. The estimated blood loss was < 5 ml for all patients. Complications included repeat surgery (after 2 weeks) for a "skip" area (n = 1) and a small temporal hematoma (n = 1), which resolved.

CONCLUSIONS

ROTCH seems to be a safe, feasible, and bloodless procedure, with a very low morbidity rate and promising outcomes.

Hemispherectomy Outcome Prediction Scale: Development and validation of a seizure freedom prediction tool

OBJECTIVE

To develop and validate a model to predict seizure freedom in children undergoing cerebral hemispheric surgery for the treatment of drug-resistant epilepsy.

METHODS

We analyzed 1267 hemispheric surgeries performed in pediatric participants across 32 centers and 12 countries to identify predictors of seizure freedom at 3 months after surgery. A multivariate logistic regression model was developed based on 70% of the dataset (training set) and validated on 30% of the dataset (validation set). Missing data were handled using multiple imputation techniques.

RESULTS

Overall, 817 of 1237 (66%) hemispheric surgeries led to seizure freedom (median follow-up = 24 months), and 1050 of 1237 (85%) were seizure-free at 12 months after surgery. A simple regression model containing age at seizure onset, presence of generalized seizure semiology, presence of contralateral 18-fluoro-2-deoxyglucose-positron emission tomography hypometabolism, etiologic substrate, and previous nonhemispheric resective surgery is predictive of seizure freedom (area under the curve = .72). A Hemispheric Surgery Outcome Prediction Scale (HOPS) score was devised that can be used to predict seizure freedom.

SIGNIFICANCE

Children most likely to benefit from hemispheric surgery can be selected and counseled through the implementation of a scale derived from a multiple regression model. Importantly, children who are unlikely to experience seizure control can be spared from the complications and deficits associated with this surgery. The HOPS score is likely to help physicians in clinical decision-making.

[Lessons learnt from 101 hemispheric pediatric epilepsy surgeries part ii: pitfalls and complications]

OBJECTIVE

To evaluate the spectrum of pitfalls and complications after hemisherotomy basing on a retrospective study of a large consecutive pediatric cohort of patients from a single institution.

MATERIAL AND METHODS

One hundred and one patients (med. age - 43 months) with refractory seizures underwent hemispherotomy. Developmental pathology was the anatomical substrate of disorder in 42 patients. The infantile post-stroke scarring and gliosis was the origin of epilepsy in the majority of 43 cases with acquired etiology. The progressive pathology (RE, S-W and TS) was the etiology in the rest of children (16 cases). The lateral periinsular technique was used to isolate the sick hemisphere in 55 patients; the vertical parasagittal approach was employed in 46 cases. Median perioperative blood loss constituted 10.5 ml/kg, but was markedly larger in kids with hemimegaly (52.8 ml/kg); 57 patients needed hemotransfusion during surgery. Median length of stay in ICU was 14.7 hours, and the length of stay in the hospital until discharge - 6.5 days. Eight patients underwent second-look surgery to complete sectioning of undercut commissural fibers. FU is known in 91 patients (med. length - 1.5 years).

RESULTS

Major surgical complications with serious hemorrhage and/or surgery induced life-threatening events developed in 7 patients (one of them has died on the 5^th day post-surgery for the causes of brain edema and uncontrolled hyponatremia). Various early and late infectious complications were noted in 4 cases. Ten patients experienced new not anticipated but temporary neurological deficit. Nine patients needed shunting for the causes of hydrocephalus within several first months post-hemispherotomy. Early seizure onset was associated with probability of all complications in general (p=0.02), and developmental etiology - with intraoperative bleeding and hemorrhagic complications (p=0.03).

CONCLUSION

Children with developmental etiology, particularly those with hemimegalencephaly, are most challengeable in terms of perioperative hemorrhage and serious complications. Patients with relapse or persisting seizures should be evaluated for the possibility of incomplete hemispheric isolation and have good chances to become SF by re-doing hemispherotomy.

Challenges of Epilepsy Surgery

Though frequently effective in the management of medically refractory seizures, epilepsy surgery presents numerous challenges. Selection of the appropriate candidate patients who are likely to benefit from surgery is critical to achieving seizure freedom and avoiding neurocognitive morbidity. Identifying the seizure focus and mapping epileptogenic networks involves an interdisciplinary team dedicated to formulating a safe and effective surgical plan. Various strategies can be employed either to eliminate the epileptic focus or to modulate network activity, including resection of the focus with open surgery or laser interstitial thermal therapy; modulation of epileptogenic firing patterns with responsive neurostimulation, deep brain stimulation, or vagus nerve stimulation; or non-invasive disconnection of epileptic circuits with focused ultrasound, which is also discussed in greater detail in the subsequent chapter in our series. We review several challenges of epilepsy surgery that must be thoughtfully addressed in order to ensure its success.

Surgical Anatomy of Vertical Perithalamic Hemispherotomy

BACKGROUND

Vertical perithalamic hemispherotomy was introduced by Olivier Delalande in 1992 as an alternative concept of functional hemispherectomy.

OBJECTIVE

To provide a step-by-step illustration of the surgical anatomy of this procedure.

METHODS

The descriptions in this manuscript are based on an experience of 52 hemispherotomies performed with the same technique by a single surgeon.

RESULTS

Our illustrations of the surgical anatomy and the descriptions of the surgical nuances facilitate a deep understanding for the surgical concept of Delalande's vertical hemispherotomy technique. They highlight the advantages (ie, reduced risk of inadvertent damage to the contralateral hemisphere and a clear orientation by defined anatomical landmarks) over the recently suggested modifications to this original technique.

CONCLUSION

Olivier Delalande's original technique remains the most appealing concept of vertical hemispherotomy to us.

Minimizing blood loss in hemispherectomy for hemimegalencephaly in low-weight infants: technical note

INTRODUCTION

Drug-resistant seizures due to hemimegalencephaly in neonates and infants are a unique surgical and anesthesia challenge. While early surgery in these patients may predict a better seizure control, a lower body weight, limited blood volume, and surgical blood loss may make hemispherectomy prohibitive.

METHODS

Two infants (weight, 8.7 kg and 3.7 kg) underwent interhemispheric vertical hemispherotomy with endoscope assistance. In the first case, during the lateral disconnection, excessive bleeding prompted the surgeon to coagulate the lenticulostriate arteries at the origin from the middle cerebral artery to reduce bleeding. In the second infant, the lenticulostriate arteries were coagulated before initiating the lateral disconnection.

RESULTS

In both infants, the blood loss from lateral dissection was reduced by coagulation of lenticulostriate arteries.

CONCLUSION

The authors suggest that early coagulation of the lenticulostriate arteries is a useful strategy to minimize blood loss in low-weight infants undergoing hemispherotomy.

Enhancing outcomes of endoscopic vertical approach hemispherotomy: understanding the role of "temporal stem" residual connections causing recurrence of seizures

Objective

The authors sought to analyze the residual connections formed by the temporal stem as a cause for seizure recurrence following endoscopic vertical interhemispheric hemispherotomy and to review and compare lateral approach (perisylvian) with vertical approach surgical techniques to highlight the anatomical factors responsible for residual connections.

METHODS

This study was a retrospective analysis of patients who underwent endoscopic hemispherotomy for drug-resistant epilepsy. Postoperative MR images were analyzed. Specific attention was given to anatomical 3D-acquired thin-section T1 images to assess the extent of disconnection, which was confirmed with a diffusion tensor imaging sequence. Cadaver brain dissection was done to analyze the anatomical factors responsible for persistent connections.

RESULTS

Of 39 patients who underwent surgery, 80% (31/39) were seizure free (follow-up of 23.61 ± 8.25 months) following the first surgery. Thirty patients underwent postoperative MRI studies, which revealed persistent connections in 14 patients (11 temporal stem only; 3 temporal stem + amygdala + splenium). Eight of these 14 patients had persistent seizures. In 4 of these 8 patients, investigations revealed good concordance with the affected hemisphere, and repeat endoscopic disconnection of the residual connection was performed. Two of the 8 patients were lost to follow-up, and 2 had bihemispheric seizure onset. The 4 patients who underwent repeat endoscopic disconnection had seizure-free outcomes following the second surgery, increasing the good outcome total among all patients to 90% (35/39). Cadaveric brain dissection analysis revealed the anatomical factors responsible for the persistence of residual connections.

CONCLUSIONS

In endoscopic vertical approach interhemispheric hemispherotomy (and also vertical approach parasagittal hemispherotomy) the temporal stem, which lies deep and parallel to the plane of disconnection, is prone to be missed, which might lead to persistent or recurrent seizures. The recognition of this limitation can lead to improved seizure outcome. The amygdala and splenium are areas less commonly prone to be missed during surgery.

Long-Term Cognitive Improvement After Functional Hemispherectomy

BACKGROUND

To investigate intellectual development after functional hemispherectomy and to evaluate the favorable or unfavorable factors affecting prognosis.

METHODS

Twenty-three patients from the patient follow-up database of the Epilepsy Center of Neurosurgery were selected for this retrospective study. The inclusion criteria of the patients were functional hemispherectomy surgery, surgical age older than 6 years, patients able to complete the intelligence assessment, follow-up time not less than 2 years, and availability of complete preoperative evaluation and postoperative follow-up data. Full Scale Intelligence Quotients (FSIQ) were calculated preoperatively and at the follow-up times for each patient. Correlations between the preoperative to postoperative changes in FSIQ and risk factors (age at epilepsy onset, duration of preoperative epilepsy, postoperative changes in the electroencephalogram, seizure status after surgery, and follow-up time) were analyzed. EpiData 3.1 software was used to establish a database and SPSS 22.0 software was used for data collation and analysis, and used the matching sample Wilcoxon symbol rank and test to conduct the analysis.

RESULTS

The data of 23 patients were analyzed. The final follow-up results showed that 73.9% of the patients (17/23) had a significant increase in FSIQ scores (P = 0.006) after surgery, indicating that their cognitive function improved significantly. Successful surgery, successful postoperative seizure control, normalization of postoperative electroencephalogram, shorter disease duration before surgery, and longer recovery periods after surgery (follow-up time) were all related with good intellectual prognosis.

CONCLUSIONS

Successful functional hemispherectomy significantly improved the cognitive function of patients. Functional hemispherectomy is a safe and effective treatment for patients with intractable epilepsy caused by hemispheric lesions and can effectively promote intellectual recovery and development.

Anatomical hemispherectomy revisited-outcome, blood loss, hydrocephalus, and absence of chronic hemosiderosis

PURPOSE

To evaluate microsurgical trans-sylvian trans-ventricular anatomical hemispherectomy with regard to seizure outcome, risk of hydrocephalus, blood loss, and risk of chronic hemosiderosis in patients with intractable seizures selected for surgery using current preoperative assessment techniques.

METHODS

Out of 86 patients who underwent hemispherectomy between February 2000 and April 2019, by a single surgeon, at a tertiary care referral center, 77 patients (ages 0.2-20 years; 40 females) who had an anatomical hemispherectomy were analyzed. Five of these were 'palliative' surgeries. One-stage anatomical hemispherectomy was performed in 55 children, two-stage anatomical hemispherectomy after extraoperative intracranial monitoring in 16, and six hemispherectomies were done following failed previous resection. Mean follow-up duration was 5.7 years (range 1-16.84 years). Forty-six patients had postoperative MRI scans.

RESULTS

Ninety percent of children with non-palliative hemispherectomy achieved ILAE Class-1 outcome. Twenty-seven patients were no longer taking anticonvulsant medications. Surgical failures (n = 4) included one patient with previous meningoencephalitis, one with anti-GAD antibody encephalitis, one with idiopathic neonatal thalamic hemorrhage, and one with extensive tuberous sclerosis. There were no failures among patients with malformations of cortical development. Estimated average blood loss during surgery was 387 ml. Ten (21%) children developed hydrocephalus and required a shunt following one-stage hemispherectomy, whereas 10 (50%) patients developed hydrocephalus among those who had extraoperative intracranial monitoring. Only 20% of the shunts malfunctioned in the first year. Early malfunctions were related to the valve and later to fracture disconnection of the shunt. One patent had a traumatic subdural hematoma. None of the patients developed clinical signs of chronic 'superficial cerebral hemosiderosis' nor was there evidence of radiologically persistent chronic hemosiderosis in patients who had postoperative MRI imaging.

CONCLUSION

Surgical results of anatomical hemispherectomy are excellent in carefully selected cases. Post-operative complications of hydrocephalus and intraoperative blood loss are comparable to those reported for hemispheric disconnective surgery (hemispherotomy). The rate of shunt malfunction was less than that reported for patients with hydrocephalus of other etiologies Absence of chronic 'superficial hemosiderosis', even on long-term follow-up, suggests that anatomical hemispherectomy should be revisited as a viable option in patients with intractable seizures and altered anatomy such as in malformations of cortical development, a group that has a reported high rate of seizure recurrence related to incomplete disconnection following hemispheric disconnective surgery.

Outcome after hemispherotomy in patients with intractable epilepsy: Comparison of techniques in the Italian experience

OBJECTIVE

The objective of the study was to evaluate clinical characteristics and outcome of hemispherotomy in children and adolescents with hemispheric refractory epilepsy in an Italian cohort of patients.

METHODS

We retrospectively evaluated the clinical course and outcome of 92 patients with refractory epilepsy who underwent hemispherotomy in three Italian epilepsy centers between 2006 and 2016. Three different approaches for hemispherotomy were used: parasagittal, modified parasagittal, and lateral.

RESULTS

Mean age at epilepsy onset was 1.8 ± 2.51 years, and mean duration of epilepsy prior to surgery was 7.4 ± 5.6 years. Mean age at surgery was 9.2 ± 8.0 years. After a mean follow-up of 2.81 ± 2.4 years, 66 of 90 patients (two lost from follow-up, 73.3%) were seizure-free (Engel class I). The etiology of epilepsy was related to acquired lesions (encephalomalacia or gliosis) in 44 patients (47.8%), congenital malformations (cortical dysplasia, hemimegalencephaly, other cortical malformations) in 38 (41.3%), and progressive conditions (Rasmussen or Sturge-Weber syndrome) in 10 patients (10.9%). Regarding seizure outcome, we could not identify statistically significant differences between vertical and lateral approaches (p = 0.154). Seizure outcome was not statistically different in patients with congenital vs acquired or progressive etiologies (p = 0.43). Acute postoperative seizures (APOS) correlated with poor outcome (p < 0.05). On multivariate analysis, presurgical focal to bilateral tonic-clonic seizures (Odds Ratio (OR) = 3.63, 95% Confidence Interval (CI): 1.86-15.20, p = 0.048) independently predicted seizure recurrence. Twenty-one patients (22.8%) exhibited postoperative complications, with no unexpected and persistent neurological deficit. More than 50% of the patients completely tapered drugs.

SIGNIFICANCE

Our data confirm hemispherotomy to be a safe and effective procedure in patients with drug resistant epilepsies due to hemispheric lesions. Presurgical focal to bilateral tonic-clonic seizures are the strongest predictor of seizure recurrence after surgery, independently from the type of hemispherotomy.

Endoscope-assisted (with robotic guidance and using a hybrid technique) interhemispheric transcallosal hemispherotomy: a comparative study with open hemispherotomy to evaluate efficacy, complications, and outcome

OBJECTIVEEndoscope-assisted hemispherotomy (EH) has emerged as a good alternative option for hemispheric pathologies with drug-resistant epilepsy.METHODSThis was a prospective observational study. Parameters measured included primary outcome measures (frequency, severity of seizures) and secondary outcomes (cognition, behavior, and quality of life). Blood loss, operating time, complications, and hospital stay were also taken into account. A comparison was made between the open hemispherotomy (OH) and endoscopic techniques performed by the senior author.RESULTSOf 59 cases (42 males), 27 underwent OH (8 periinsular, the rest vertical) and 32 received EH. The mean age was 8.65 ± 5.41 years (EH: 8.6 ± 5.3 years; OH: 8.6 ± 5.7 years). Seizure frequency per day was 7 ± 5.9 (EH: 7.3 ± 4.6; OH: 15.0 ± 6.2). Duration of disease (years since first episode) was 3.92 ± 1.24 years (EH: 5.2 ± 4.3; OH: 5.8 ± 4.5 years). Number of antiepileptic drugs per patient was 3.9 ± 1.2 (EH: 4.2 ± 1.2; OH: 3.8 ± 0.98). Values for the foregoing variables are expressed as the mean ± SD. Pathologies included the following: postinfarct encephalomalacia in 19 (EH: 11); Rasmussen's syndrome in 14 (EH: 7); hemimegalencephaly in 12 (EH: 7); hemispheric cortical dysplasia in 7 (EH: 4); postencephalitis sequelae in 6 (EH: 2); and Sturge-Weber syndrome in 1 (EH: 1). The mean follow-up was 40.16 ± 17.3 months. Thirty-nine of 49 (79.6%) had favorable outcomes (International League Against Epilepsy class I and II): in EH the total was 19/23 (82.6%) and in OH it was 20/26 (76.9%). There was no difference in the primary outcome between EH and OH (p = 0.15). Significant improvement was seen in the behavioral/quality of life performance, but not in IQ scores in both EH and OH (p < 0.01, no intergroup difference). Blood loss (p = 0.02) and hospital stay (p = 0.049) were less in EH.CONCLUSIONSEH was as effective as the open procedure in terms of primary and secondary outcomes. It also resulted in less blood loss and a shorter postoperative hospital stay.

Surgical treatment for refractory epilepsy

The goal of any epilepsy surgery is to improve patient's quality of life by achieving seizure freedom or by reducing the frequency of severely debilitating seizures. To achieve this goal, non-invasive and invasive diagnostic methods must precisely delineate the epileptogenic zone (EZ), which is defined as the area that needs to be resected to obtain seizure freedom. At the same time, the correct identification of eloquent brain areas is inevitable to avoid new neurological deficits from surgery. In recent years, the technical advances in diagnostics have enabled us to achieve these goals in an increasing number of cases. As a consequence, and with new surgical treatment options available, the number of patients who might benefit from epilepsy surgery is constantly increasing. Especially in pediatric epilepsy, early surgical intervention is becoming frequently advocated as it has been shown to improve cognitive and behavioral outcome. Specialized epilepsy centers and multidisciplinary teams are required to provide adequate care and treatment. The goal of this review is to describe important diseases that are accessible to epilepsy surgery and to give an overview of current diagnostic methods. The focus lies on established as well as novel techniques in epilepsy surgery. The presurgical work-up and patient selection is outlined.

Generalized seizures presurgically in a cohort of children with hemispherectomy: Predictors and a potential link to surgical outcome?

PURPOSE

Generalized seizures were often thought to be contraindications for hemispherectomy. However, few studies had investigated this issue comprehensively, as well as the predictors for generalized seizures in hemispheric lesion. We studied the predictors of generalized seizures and their potential link to seizure outcomes in a cohort of children who underwent hemispherectomy.

METHODS

A cohort of 76 children with hemispherectomy were reviewed and dichotomized into two groups with and without generalized seizures confirmed by vEEG presurgically. All preoperative evaluation data correlated to generalized seizures and postoperative prognosis were collected and analysed.

RESULTS

Of 76 patients, 11 (14.5%) cases were documented with various generalized seizures, including atypical absence (54.5%, 6/11), myoclonic (45.5%, 5/11), atonic (36.4%, 4/11), myoclonic-atonic (18.2%, 2/11), myoclonic-absence (9.1%, 1/11) and spasms (9.1%). Electrical status epilepticus during sleep (ESES) was recorded in 3 patients (27.3%, 3/11). At last follow-up, 72.7% (8/11) patients remained seizure-free. ESES was a predictor of generalized seizures (χ² = 4.69, P = 0.043). No correlation was found between generalized seizures and unfavourable postoperative seizure outcome (P = 0.153). For different seizure types, focal to bilateral tonic-clonic seizures (P = 0.020) and myoclonic-atonic seizures (P = 0.002) might correlate with unfavourable outcomes.

CONCLUSION

Generalized seizures were not an absolute contraindication for hemispherectomy. Those patients with ESES might experience generalized seizures presurgically. Focal to bilateral tonic-clonic seizures and myoclonic-atonic seizures pre-surgery may indicate unfavourable post-operative seizure outcomes.

Trapped ipsilateral lateral ventricle: a delayed complication of hemispherotomy for Rasmussen's encephalitis

Hemispherotomy is the currently preferred surgical treatment option for refractory unihemispheric epilepsies. The incidence of hydrocephalus is greatly reduced in this disconnective procedure when compared with the resective procedure of anatomical hemispherectomy. We describe the occurrence of ipsilateral trapped lateral ventricle months after hemispherotomy for Rasmussen's encephalitis. There is enough evidence to suggest that this rare and interesting complication is due to the local inflammatory changes associated with the surgical trauma.

[Hemispherectomy in the treatment of pediatric symptomatic epilepsy of children]

INTRODUCTION AND PURPOSE

Hemispherectomy is a recognized option in the treatment of symptomatic forms of intractable focal epilepsy in patients with developmental brain malformations and some acquired lesions of one the hemispheres. The prognosis for an outcome of the technique is important in terms of the indications for surgical treatment.

MATERIAL AND METHODS

We described the hemispherectomy technique and its variants and analyzed our own experience of surgery in 40 children. The most common (27 cases) brain pathology was extended unilateral cortical dysplasia with polymicro- or pachygyria and consequences of perinatal stroke. Six children had Rasmussen encephalitis; 6 patients had hemimegalencephaly; 1 child with Sturge-Weber syndrome had angiomatosis of the soft meninges. The patients' mean age was 3 years. Functional hemispherectomy (hemispherotomy) was used in most cases (37); 3 patients underwent anatomical hemispherectomy.

RESULTS

At the time of discharge, seizures resolved in all patients; later, no seizure recurrence was observed in 25 out of 29 cases with known follow-up (the follow-up median was 2.5 years), which corresponded to class 1 outcomes on the ILAE scale (86%). Serious complications developed in 2 cases; 1 patient died; hydrocephalus and the need for bypass surgery occurred in other 2 children. These results are discussed along with the literature data, and the indications for hemispherectomy are provided.

CONCLUSION

Hemispherectomy is a reliable and effective technique for treatment of symptomatic hemispheric forms of epilepsy in children. More than in 80% of patients with congenital or acquired pathology of one of the cerebral hemispheres, its deafferentation or resection leads to persistent elimination of seizures. Children with severe forms of intractable epilepsy should be promptly referred to dedicated centers to address the issue of advisability of surgical treatment.

Immediate termination of electrical status epilepticus in sleep after hemispherotomy is associated with significant progress in language development

AIM

To study the effect of hemispherotomy on electrical status epilepticus in sleep (ESES) and language development.

METHOD

Children with a confirmed diagnosis of ESES prior to surgery and a minimum of 24 months of developmental follow-up data were compared with age-matched controls without ESES. Language quotients (LQs) were calculated before and after surgery.

RESULTS

Eleven patients (five females, six males) and 21 controls (11 females, 10 males) were included. Before surgery a significantly higher number of children in the study group (n=9) demonstrated severe developmental delay compared with children in the control group (n=13; p=0.015). In the study group ESES remitted immediately after surgery in 10 children, and a significant catch-up in LQs was observed in this group (preoperative mean 40.0 [standard deviation (SD) 22.2, interquartile range (IQR) 30.0-62.0]; postoperative mean 73.0 [SD 33.5, IQR 41.0-97.0]; p=0.037). There was no significant difference compared with controls at last follow-up after surgery (study group: five with severe impairment; control group: eight with severe impairment [p=0.971]). Overall, a favourable developmental outcome was associated with freedom from seizures (seizure-free group: median preoperative LQ 61.5, median postoperative LQ 78.0 [p=0.017]; seizure group: median preoperative LQ 35.5, median postoperative LQ 56.5 [p=0.273]) and antiepileptic drug withdrawal (off medication: median preoperative LQ 49.5, median postoperative LQ 78.0 [p=0.011]; on medication: median preoperative LQ 78.0, median postoperative LQ 83.5 [p=0.889]).

INTERPRETATION

Children with ESES showed significantly lower preoperative language abilities than children without ESES. In cases with remission of ESES after surgery, marked improvement in LQs was noticed. This improvement cannot be fully explained by seizure-freedom alone as seizure-free children without preoperative ESES showed less improvement.

Presurgical evaluation of pediatric epilepsy patients prior to hemispherotomy: the prognostic value of 18F-FDG PET

OBJECTIVE The objective of this study was to investigate whether fluorine-18 fluorodeoxyglucose PET (¹⁸F-FDG PET) can help to predict seizure outcome after hemispherotomy and therefore may be useful in decision making and patient selection. METHODS Children and adolescents less than 18 years of age who underwent ¹⁸F-FDG PET studies during presurgical evaluation prior to hemispherotomy and had follow-up data of at least 12 months after surgery were included. Seizure outcome was classified according to the recommendations of the International League Against Epilepsy. PET data were reevaluated by two specialists in nuclear medicine blinded to clinical data and to MRI. MRI studies were also reinterpreted visually by an experienced neuroradiologist blinded to clinical data and PET findings. RESULTS Thirty-five patients (17 girls) with a median age of 5 years (range 0.4-17.8 years) were evaluable. Of the 35 patients, 91.4% were seizure free after surgery, including 100% of those with unilateral ¹⁸F-FDG-PET hypometabolism compared with only 75% of those with bilateral hypometabolism. With respect to MRI, seizure freedom after surgery was observed in 96.4% of the patients with unilateral lesions compared with only 71.4% in those with bilateral MRI lesions. The best seizure outcomes were noted in patients with unilateral findings in both PET and MRI (100% seizure freedom) whereas only 50% of those with bilateral findings in both imaging techniques were seizure free. Furthermore, 100% of the patients with unilateral PET hypometabolism and bilateral MRI findings were also seizure free, but only 87.5% of those with bilateral PET hypometabolism and unilateral MRI findings. CONCLUSIONS According to these results, candidate selection for hemispherotomy can be optimized by the use of ¹⁸F-FDG PET as part of a multimodal presurgical evaluation program, especially in patients with inconsistent (bilateral) MRI findings.

Psychopathology in adolescents with TLE and FLE

BACKGROUND

To describe the rates and types of psychiatric disorders among adolescents with chronic symptomatic epilepsies and to evaluate syndrome-specific differences between temporal lobe (TLE) and frontal lobe (FLE) epilepsies.

METHODS

A cross-sectional single-center study design applying the Youth Self Report (YSR) to investigate psychopathological symptoms and the Weinberger Adjustment Inventory (WAI) to investigate personality dimensions was used. Consecutive adolescents between 14 and 18 years of age with drug-resistant symptomatic TLE and FLE were investigated during pre-surgical evaluation prior to epilepsy surgery. Data from twenty-eight patients (19 with TLE and 9 with FLE) were analyzed for this report.

RESULTS

Compared with the test norm, higher prevalence rates and a wider range of psychopathological symptoms were seen in patients with TLE. This result was not seen in patients with FLE. Concerning personality dimensions, significantly higher values of repressive defensiveness and significantly lower values of positive emotion and confidence were found in patients with TLE. In contrast, significantly lower levels of distress and significantly higher levels of repressive defensiveness and denial of distress were seen in patients with FLE. Comparing TLE with FLE, a significantly higher mean score for distress, and a significantly lower mean score for positive emotion and denial of distress were found in patients with TLE.

CONCLUSION

In summary, psychiatric comorbidity was frequently found in this sample of youths with chronic drug-resistant localization-related epilepsies. Although results have to be interpreted with caution because of the small sample size, psychiatric symptomatology was significantly different between TLE and FLE. Our results show that continuous and syndrome-specific psychiatric monitoring is essential in young patients with epilepsy.

Vertical parasagittal hemispherotomy for Sturge-Weber syndrome in early infancy: case report and literature review

INTRODUCTION

The authors here present a rare case of a 3-month-old infant with unilateral Sturge-Weber syndrome (SWS) who had excellent seizure control and no aggravation of previous existed neurological deficits after vertical parasagittal hemispherotomy (VPH). To our knowledge, this patient with SWS was the youngest one who received VPH.

CASE DESCRIPTION

The use of VPH results in a successful treatment of intractable epilepsy in a patient with seizure onset in early infancy. At follow-up, the patient's neurodevelopmental status has been improved since the surgery.

DISCUSSION

It is generally accepted that early-onset seizures in children with SWS are associated with worse neurological and developmental outcomes. However, when surgical treatment should be considered and how it should be performed remain a longstanding controversy. We promote early surgery in children with SWS and early-onset epilepsy.

CONCLUSION

We suggest that VPH may be a useful adjuvant in the management of SWS with refractory epilepsy in early infancy and this procedure carries low neurological risk.

Complete prefrontal lobe isolation surgery for recurrent epilepsy: A case report

Epileptogenic focus resection is less effective for the treatment of frontal lobe epilepsy compared with temporal lobe epilepsy. However, there is currently a lack of effective therapeutic options for patients with frontal lobe epilepsy who are unsuitable for epileptogenic focus resection (such patients with epileptogenic foci in one frontal lobe in which the precise epileptic foci cannot be determined), or who experience recurrent epilepsy following epileptogenic focus resection. The present study reports a patient with frontal lobe epilepsy who underwent successful frontal lobe isolation surgery following a previous unsuccessful epileptogenic focus resection surgery. To ensure complete isolation of the prefrontal lobe, the surgery included division of the anterior commissure and the anterior part of the corpus callosum. The patient was followed-up for 16 months. Although the follow-up electroencephalogram presented a number of sharp waves on the affected side, the patient did not experience any seizures. The results suggest that prefrontal lobe isolation is an effective method of treating frontal lobe epilepsy, as division of the anterior commissure and the anterior part of the corpus callosum ensures disconnection of the prefrontal lobe from other regions of the brain.

Predicting hand function after hemidisconnection

Hemidisconnections (i.e. hemispherectomies or hemispherotomies) invariably lead to contralateral hemiparesis. Many patients with a pre-existing hemiparesis, however, experience no deterioration in motor functions, and some can still grasp with their paretic hand after hemidisconnection. The scope of our study was to predict this phenomenon. Hypothesizing that preserved contralateral grasping ability after hemidisconnection can only occur in patients controlling their paretic hands via ipsilateral corticospinal projections already in the preoperative situation, we analysed the asymmetries of the brainstem (by manual magnetic resonance imaging volumetry) and of the structural connectivity of the corticospinal tracts within the brainstem (by magnetic resonance imaging diffusion tractography), assuming that marked hypoplasia or Wallerian degeneration on the lesioned side in patients who can grasp with their paretic hands indicate ipsilateral control. One hundred and two patients who underwent hemidisconnections between 0.8 and 36 years of age were included. Before the operation, contralateral hand function was normal in 3/102 patients, 47/102 patients showed hemiparetic grasping ability and 52/102 patients could not grasp with their paretic hands. After hemidisconnection, 20/102 patients showed a preserved grasping ability, and 5/102 patients began to grasp with their paretic hands only after the operation. All these 25 patients suffered from pre- or perinatal brain lesions. Thirty of 102 patients lost their grasping ability. This group included all seven patients with a post-neonatally acquired or progressive brain lesion who could grasp before the operation, and also all three patients with a preoperatively normal hand function. The remaining 52/102 patients were unable to grasp pre- and postoperatively. On magnetic resonance imaging, the patients with preserved grasping showed significantly more asymmetric brainstem volumes than the patients who lost their grasping ability. Similarly, these patients showed striking asymmetries in the structural connectivity of the corticospinal tracts. In summary, normal preoperative hand function and a post-neonatally acquired or progressive lesion predict a loss of grasping ability after hemidisconnection. A postoperatively preserved grasping ability is possible in hemiparetic patients with pre- or perinatal lesions, and this is highly likely when the brainstem is asymmetric and especially when the structural connectivity of the corticospinal tracts within the brainstem is asymmetric.

Anatomic Understanding of Vertical Hemispherotomy With Cadaveric Brains and Intraoperative Photographs

BACKGROUND

Vertical hemispherotomy is performed in hemispheric epilepsy to disconnect commissural fibers, projecting fibers, and limbic system from the affected side of the brain with minimal parenchyma removal. However, anatomic understanding of this surgery is generally difficult.

OBJECTIVE

To present the vertical hemispherotomy procedures using cadaveric brains and intraoperative photographs.

METHODS

Two formalin-fixed adult cadaveric brains were used to demonstrate vertical hemispherotomy. Intraoperative photographs were taken of a 19-year-old man with intractable epilepsy due to head trauma in infancy.

RESULTS

After coronal skin incision along the coronal suture, bifrontal craniotomy and a C-shaped dural incision from lateral to medial to the midline are performed. The interhemispheric fissure is dissected from anterior to posterior. Interhemispheric total corpus callosotomy is performed to disconnect commissural fibers. Corticotomy on the cingulate gyrus is performed to approach the lateral ventricle. The lateral border of the thalamus is cut from posterior to anterior until exposing the inferior horn of the lateral ventricle and hippocampal head to disconnect projecting fibers. At the anteromedial side of the hippocampus, the inferior part of the amygdala and uncal gyrus is removed, exposing the basal cistern to disconnect the hippocampus and amygdala. The posterior column of the fornix at the trigone of the lateral ventricle is resected to disconnect the limbic system. Projecting fibers from the anterior frontal lobe are disconnected.

CONCLUSION

A step-by-step procedure using cadaveric brains and intraoperative photographs provide a better anatomic understanding of vertical hemispherotomy.

Hemispheric surgery for refractory epilepsy: a systematic review and meta-analysis with emphasis on seizure predictors and outcomes

OBJECT

Conflicting conclusions have been reported regarding several factors that may predict seizure outcomes after hemispheric surgery for refractory epilepsy. The goal of this study was to identify the possible predictors of seizure outcome by pooling the rates of postoperative seizure freedom found in the published literature.

METHODS

A comprehensive literature search of PubMed, Embase, and the Cochrane Library identified English-language articles published since 1970 that describe seizure outcomes in patients who underwent hemispheric surgery for refractory epilepsy. Two reviewers independently assessed article eligibility and extracted the data. The authors pooled rates of seizure freedom from papers included in the study. Eight potential prognostic variables were identified and dichotomized for analyses. The authors also compared continuous variables within seizure-free and seizure-recurrent groups. Random- or fixed-effects models were used in the analyses depending on the presence or absence of heterogeneity.

RESULTS

The pooled seizure-free rate among the 1528 patients (from 56 studies) who underwent hemispheric surgery was 73%. Patients with an epilepsy etiology of developmental disorders, generalized seizures, nonlateralization on electroencephalography, and contralateral MRI abnormalities had reduced odds of being seizure-free after surgery.

CONCLUSIONS

Hemispheric surgery is an effective therapeutic modality for medically intractable epilepsy. This meta-analysis provides useful evidence-based information for the selection of candidates for hemispheric surgery, presurgical counseling, and explanation of seizure outcomes.

Functional hemispherectomy for catastrophic epilepsy in very young infants: technical considerations and complication avoidance

PURPOSE

We report on our experience in performing peri-insular functional hemispherectomy (PIH) in very young infants with catastrophic epilepsy.

METHODS

We retrospectively reviewed the medical charts of all infants with catastrophic epilepsy that underwent PIH under the age of 4 months at our institution.

RESULTS

Four infants (three female, one male) were included (median age at time of surgery 2.9 months, range from 2.4 to 4.2 months; median patient's weight at time of surgery 5650 g, range from 4300 to 7500 g). None of the patients experienced hemodynamic instability during surgery. All four patients were given red blood cell replacement (median 435 ml, range from 230 to 800 ml), three of the four patients experienced coagulopathy during surgery and were given platelet cells transfusion in one (50 ml) and fresh frozen plasma in two patients (191 and 320 ml). Two patients experienced severe complications that, however, did not cause a permanent morbidity due to prompt diagnosis and correct management. After a median follow-up time of 4.3 years (range from 1.3 to 7.9 years), three of four patients are completely seizure free. The remaining patient is experiencing brief daily staring episodes. All of them have a hemiparesis but are fully ambulatory and have a useful upper limb function.

CONCLUSION

In catastrophic epilepsy, PIH within the first months of life is feasible provided that an experienced multidisciplinary team is involved. Awareness of surgical challenges and potential complications is indispensible when the life-threatening nature of the epilepsy compels neurosurgeons to operate at this very young age.

Improvement of language development after successful hemispherotomy

PURPOSE

To investigate language development after functional hemispherotomy and to evaluate prognostic factors for (un-)favourable outcomes.

METHODS

Children and adolescents who had vertical perithalamic hemispherotomy at the Medical University Wien (MUW) paediatric epilepsy centre were identified from a prospectively maintained database. Inclusion criteria were: complete clinical, neurophysiological and neuropsychological data, seizure freedom and a minimum follow-up of 12 months after surgery. The language quotients (LQ) prior to surgery and at last follow-up were calculated for each child. In addition, associations between pre- to post-surgical changes in LQ and the following variables were examined: age at epilepsy-onset, age at surgery and duration of epilepsy prior to surgery, aetiology, side of surgery, interictal EEG including sleep organization before and 12 months after surgery and antiepileptic-drug (AED) withdrawal state at last follow-up. Analyses were carried out in SPSS version 20.0 (SPSS Inc., Chicago, IL, USA). Nonparametric Wilcoxon and chi-square tests were applied, as required.

RESULTS

Data from 28 children (14 female) were analyzed. The median age at epilepsy surgery was 64.5 months. The median follow-up after surgery was 3.0 years (±2.6 years, range 12 months to 12 years). Significant gains in LQs at last follow-up were found in 31% of the children (p=0.008). Short disease duration prior to surgery, acquired pathology, lack of epileptiform EEG discharges in the contralateral hemisphere and/or normalization of EEG sleep patterns after surgery, and successful AED withdrawal were linked to favourable language outcomes.

CONCLUSION

Successful and early hemispherotomy results in improvement of language function in the intact hemisphere.

A long-term patient perspective after hemispherotomy--a population based study

PURPOSE

Explore the long-term life situation for Swedish hemispherotomy patients reporting not only seizure outcome but also patients' perspectives on function, quality of life (QoL) and satisfaction with the surgery.

METHODS

This population based study uses prospectively collected data from the Swedish National Epilepsy Surgery Register. An independent researcher interviewed patients or parents, using two patient oriented questionnaires.

RESULTS

Twenty-nine patients underwent hemispherotomy in Sweden after 1995 and had a five- or ten-year follow-up. At the 2-year follow-up 55% (16/29) were seizure-free since surgery, and 11/29 (38%) were seizure-free at the long term follow up. Twenty-six (90%) participated in this study. Median time to interview was 13.5 years; 9/26 (35%) were seizure-free then; 23% were off antiepileptic medication. In those not seizure-free, seizures were considered mild or moderate; 11% attended mainstream school and 3/12 adults lived independently. Most parents both of seizure-free and non seizure-free patients reported QoL and general health to be very good/good; 73% were satisfied/very satisfied with the hemispherotomy.

CONCLUSION

In this series there were more long-term recurrences than previously reported. This might be related to the lower level of function of this cohort and higher percentage of developmental aetiologies compared to other series. However, most hemispherotomy patients have a good QoL in the long run and feel that the operation was worthwhile, even when it did not stop seizures. The majority had persisting impairments. Proxies were not very concerned about seizures, indicating that reduction in seizure frequency and/or severity may be an important gain with hemispherotomy.

Pediatric epilepsy surgery

Medically refractory epilepsy is a significant cause of morbidity and mortality in pediatric neurology. Surgical intervention has been well established as a viable treatment option in certain cases. This article reviews the process of selecting appropriate patients using the latest advances in neuroimaging and electrophysiologic techniques. It also discusses the various surgical techniques currently available, including recent advances in minimally invasive approaches.

Endoscopy-Assisted Interhemispheric Transcallosal Hemispherotomy

BACKGROUND:

Various hemispherotomy techniques have been developed to reduce complication rates and achieve the best possible seizure control.

OBJECTIVE:

To present a novel and minimally invasive endoscopy-assisted approach to perform this procedure.

METHODS:

Endoscopy-assisted interhemispheric transcallosal hemispherotomy was performed in 5 children (April 2013-June 2014). The procedure consisted of performing a small craniotomy (4 × 3 cm) just lateral to midline using a transverse skin incision. After dural opening, the surgery was performed with the assistance of a rigid high-definition endoscope, and bayoneted self-irrigating bipolar forceps and other standard endoscopic instruments. Steps included a complete corpus callosotomy followed by the disconnection of the hemisphere at the level of the basal nuclei and thalamus. The surgeries were performed in a dedicated operating room with intraoperative magnetic resonance imaging and neuronavigation. Intraoperative magnetic resonance imaging confirmed a total disconnection.

RESULTS:

The pathologies for which surgeries were performed included sequelae of middle a cerebral artery infarct (n = 2), Rasmussen syndrome (n = 1), and hemimegalencephaly (2). Four patients had an Engel class I and 1 patient had a class II outcome at a mean follow-up of 10.2 months (range, 3-14 months). The mean blood loss was 80 mL, and mean operating time was 220 minutes. There were no complications in this study.

CONCLUSION:

This study describes a pilot novel technique and the feasibility of performing a minimally invasive, endoscopy-assisted hemispherotomy.

Interhemispheric Vertical Hemispherotomy: A Single Center Experience

PURPOSE

Hemispheric epileptogenic lesions such as hemimegalencephaly often manifest as intractable epilepsy in early infancy. Hemispherotomy is the treatment of choice for controlling intractable hemispheric epilepsy. Less invasive procedures are desirable for surgery on infants with low body weight. This study compared our experience with interhemispheric vertical hemispherotomy (IVH) and peri-insular lateral hemispherotomy (PIH).

METHODS

Thirteen consecutive patients underwent hemispherotomy for treatment of intractable epilepsy in our institution between 2001 and 2012. The etiology of epilepsy included hemimegalencephaly in 7 patients and cortical dysplasia in 3. PIH was performed on the first 5 patients and IVH on the last 8 patients. In the latter procedure, complete section of the corpus callosum was first performed via the interhemispheric approach. After removing part of the cingulate gyrus, section of the descending fibers was performed anterolaterally to the thalamus. Clinical characteristics, duration of operation and amount of blood transfusion were compared between the PIH and IVH groups.

RESULTS

There was no difference in age at surgery, body weight and age of epilepsy onset between the two groups. No surgery-related death was observed. No patients required shunt operation. One patient who underwent IVH required reoperation for incomplete disconnection. The amount of intraoperative blood transfusion was smaller and the total duration of operation was shorter in the IVH group than in the PIH group.

CONCLUSION

The interhemispheric approach minimizes cortical resection and may be less invasive than PIH. IVH is advantageous for treating infants with low body weight.