Cingulate gyrus epilepsy: semiology, invasive EEG, and surgical approaches

OBJECTIVE

The semiology of cingulate gyrus epilepsy is varied and may involve the paracentral area, the adjacent limbic system, and/or the orbitofrontal gyrus. Invasive electroencephalography (iEEG) recording is usually required for patients with deeply located epileptogenic foci. This paper reports on the authors' experiences in the diagnosis and surgical treatment of patients with focal epilepsy originating in the cingulate gyrus.

METHODS

Eighteen patients (median age 24 years, range 5-53 years) with a mean seizure history of 23 years (range 2-32 years) were analyzed retrospectively. The results of presurgical evaluation, surgical strategy, and postoperative pathology are reported, as well as follow-up concerning functional morbidity and seizures (median follow-up 7 years, range 2-12 years).

RESULTS

Patients with cingulate gyrus epilepsy presented with a variety of semiologies and scalp EEG patterns. Prior to ictal onset, 11 (61%) of the patients presented with aura. Initial ictal symptoms included limb posturing in 12 (67%), vocalization in 5, and hypermotor movement in 4. In most patients (n = 16, 89%), ictal EEG presented as widespread patterns with bilateral hemispheric origin, as well as muscle artifacts obscuring the onset of EEG during the ictal period in 11 patients. Among the 18 patients who underwent resection, the pathology revealed mild malformation of cortical development in 2, focal cortical dysplasia (FCD) Ib in 4, FCD IIa in 4, FCD IIb in 4, astrocytoma in 1, ganglioglioma in 1, and gliosis in 2. The seizure outcome after surgery was satisfactory: Engel class IA in 12 patients, IIB in 3, IIIA in 1, IIIB in 1, and IVB in 1 at the 2-year follow-up.

CONCLUSIONS

In this study, the authors exploited the improved access to the cingulate epileptogenic network made possible by the use of 3D electrodes implanted using stereoelectroencephalography methodology. Under iEEG recording and intraoperative neuromonitoring, epilepsy surgery on lesions in the cingulate gyrus can result in good outcomes in terms of seizure recurrence and the incidence of postoperative permanent deficits.

Status of current medicolegal reform in the United States: a neurosurgical perspective

OBJECTIVE

There are approximately 85,000 lawsuits filed against medical practitioners every year in the US. Among these lawsuits, neurosurgery has been identified as a "high-risk specialty" with exceptional chance of having medical malpractice suits filed. Major issues affecting the overall medicolegal environment include tort reform, the formation of medical review panels, the increasing practice of defensive medicine, and the rising costs of medical insurance. In this study, the authors provide a concise update of the current medicolegal environments of the 50 states and provide a general guide to favorable and unfavorable states in which to practice neurosurgery.

METHODS

Data were acquired related to state-by-state medical review panel status, noneconomic damage caps, economic damage caps, and civil suit filing fees. States were placed into 5 categories based on the status of their current medicolegal environment.

RESULTS

Of the 50 states in the US, 18 have established a medical review panel process. Fifteen states have a mandatory medical review process, whereas 3 states rely on a voluntary process. Thirty-five states have tort reform and have placed a cap on noneconomic damages. These caps range from $250,000 to $2,350,000, with the median cap of $465,900. Only 8 states have placed a cap on total economic damages. These caps range from $500,000 to $2,350,000, with the median cap of $1,050,000. All states have a filing fee for a medical malpractice lawsuit. These costs range from $37 to $884, with the median cost for filing of $335.

CONCLUSIONS

Medicolegal healthcare reform will continue to play a vital role in physicians' lives. It will dictate if physicians may practice proactively or be forced to act defensively. With medicolegal reform varying greatly among states, it will ultimately dictate if physicians move into or away from certain states and thus guide the availability of healthcare services. A desirable legal system for neurosurgeons, including caps on economic and noneconomic damages and availability of medical review panels, can lead to safer practice.

Prognostic factors of postoperative seizure outcomes in older patients with temporal lobe epilepsy

OBJECTIVE

The authors of this study aimed to investigate surgical outcomes and prognostic factors in older patients with drug-resistant temporal lobe epilepsy (TLE) who had undergone resective surgery.

METHODS

Data on patients older than 45 years of age with drug-resistant TLE who had undergone resective surgery at Sanbo Brain Hospital, Capital Medical University, between January 2009 and August 2017 were retrospectively collected. Postoperative seizure outcomes were evaluated according to the International League Against Epilepsy (ILAE) classification. Patients belonging to ILAE classes 1 and 2 were classified as having a favorable outcome, whereas patients belonging to ILAE classes 3-6 were classified as having an unfavorable outcome. Univariate analysis and multivariate logistic regression analysis were used to identify the potential predictors of seizure outcomes.

RESULTS

A total of 45 patients older than 45 years of age who had undergone resective epilepsy surgery for TLE were included in the present study. Eight (17.8%) of 45 patients had preoperative comorbidity in addition to seizures. The average age at the time of surgery was 51.76 years, and the average duration of epilepsy at the time surgery was 18.01 years. After an average follow-up period of 4.53 ± 2.82 years (range 2-10 years), 73.3% (33/45) of patients were seizure free. Surgical complications were observed in 13.3% of patients. Univariate and multivariate analyses revealed that an MRI-negative finding is the only independent predictor of unfavorable seizure outcomes (OR 0.06, 95% CI 0.01-0.67, p = 0.023).

CONCLUSIONS

Resective surgery is a safe and effective treatment for older patients with drug-resistant TLE. An MRI-negative finding independently predicts unfavorable seizure outcomes.

Postcranioplasty seizures following decompressive craniectomy and seizure prophylaxis: a retrospective analysis at a single institution

OBJECTIVE

Cranioplasty is a relatively simple and less invasive intervention, but it is associated with a high incidence of postoperative seizures. The incidence of, and the risk factors for, such seizures and the effect of prophylactic antiepileptic drugs (AEDs) have not been well studied. The authors' aim was to evaluate the risk factors that predispose patients to postcranioplasty seizures and to examine the role of seizure prophylaxis in cranioplasty.

METHODS

The records of patients who had undergone cranioplasty at the authors' medical center between 2009 and 2014 with at last 2 years of follow-up were retrospectively reviewed. Demographic and clinical characteristics, the occurrence of postoperative seizures, and postoperative complications were analyzed.

RESULTS

Among the 583 patients eligible for inclusion in the study, 247 had preexisting seizures or used AEDs before the cranioplasty and 336 had no seizures prior to cranioplasty. Of these 336 patients, 89 (26.5%) had new-onset seizures following cranioplasty. Prophylactic AEDs were administered to 56 patients for 1 week after cranioplasty. No early seizures occurred in these patients, and this finding was statistically significant (p = 0.012). Liver cirrhosis, intraoperative blood loss, and shunt-dependent hydrocephalus were risk factors for postcranioplasty seizures in the multivariable analysis.

CONCLUSIONS

Cranioplasty is associated with a high incidence of postoperative seizures. The prophylactic use of AEDs can reduce the occurrence of early seizures.

Single and staged laser interstitial thermal therapy ablation for cortical tubers causing refractory epilepsy in pediatric patients

OBJECTIVE Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a novel, minimally invasive treatment for the surgical treatment of epilepsy. In this paper, the authors report on clinical outcomes for a series of pediatric patients with tuberous sclerosis complex (TSC) and medication-refractory epileptogenic cortical tubers. METHODS A retrospective chart review was performed at SUNY Upstate Golisano Children's Hospital in Syracuse, New York. The authors included all cases involving pediatric patients (< 18 years) who underwent MRgLITT for ablation of epileptogenic cortical tubers between February 2013 and November 2015. RESULTS Seven patients with cortical tubers were treated (4 female and 3 male). The patients' average age was 6.6 years (range 2-17 years). Two patients had a single procedure, and 5 patients had staged procedures. The mean time between procedures in the staged cases was 6 months. All of the patients had a meaningful reduction in seizure frequency as reported by Engel and ILAE seizure outcome classifications, and most (71.4%) of the patients experienced a reduction in AED burden. Three of the 4 patients who presented with neuropsychiatric symptoms had some improvement in these domains after laser ablation. No perioperative complications were noted. The mean duration of follow-up was 19.3 months (range 4-49 months). CONCLUSIONS Laser ablation represents a minimally invasive alternative to resective epilepsy surgery and is an effective treatment for refractory epilepsy due to cortical tubers.

Ultrasonographic features of focal cortical dysplasia and their relevance for epilepsy surgery

OBJECTIVE Surgery has proven to be the best therapeutic option for drug-refractory cases of focal cortical dysplasia (FCD)-associated epilepsy. Seizure outcome primarily depends on the completeness of resection, rendering the intraoperative FCD identification and delineation particularly important. This study aims to assess the diagnostic yield of intraoperative ultrasound (IOUS) in surgery for FCD-associated drug-refractory epilepsy. METHODS The authors prospectively enrolled 15 consecutive patients with drug-refractory epilepsy who underwent an IOUS-assisted microsurgical resection of a radiologically suspected FCD between January 2013 and July 2016. The findings of IOUS were compared with those of presurgical MRI postprocessing and the sonographic characteristics were analyzed in relation to the histopathological findings. The authors investigated the added value of IOUS in achieving completeness of resection and improving postsurgical seizure outcome. RESULTS The neurosurgeon was able to identify the dysplastic tissue by IOUS in all cases. The visualization of FCD type I was more challenging compared to FCD II and the demarcation of its borders was less clear. Postsurgical MRI showed residual dysplasia in 2 of the 3 patients with FCD type I. In all FCD type II cases, IOUS allowed for a clear intraoperative visualization and demarcation, strongly correlating with presurgical MRI postprocessing. Postsurgical MRI confirmed complete resection in all FCD type II cases. Sonographic features correlated with the histopathological classification of dysplasia (sonographic abnormalities increase continuously in the following order: FCD IA/IB, FCD IC, FCD IIA, FCD IIB). In 1 patient with IOUS features atypical for FCD, histopathological investigation showed nonspecific gliosis. CONCLUSIONS Morphological features of FCD, as identified by IOUS, correlate well with advanced presurgical imaging. The resolution of IOUS was superior to MRI in all FCD types. The appreciation of distinct sonographic features on IOUS allows the intraoperative differentiation between FCD and non-FCD lesions as well as the discrimination of different histological subtypes of FCD. Sonographic demarcation depends on the underlying degree of dysplasia. IOUS allows for more tailored resections by facilitating the delineation of the dysplastic tissue.

Strategic hospital partnerships: improved access to care and increased epilepsy surgical volume

OBJECTIVE Surgical treatment of patients with medically refractory focal epilepsy is underutilized. Patients may lack access to surgically proficient centers. The University of California, Irvine (UCI) entered strategic partnerships with 2 epilepsy centers with limited surgical capabilities. A formal memorandum of understanding (MOU) was created to provide epilepsy surgery to patients from these centers. METHODS The authors analyzed UCI surgical and financial data associated with patients undergoing epilepsy surgery between September 2012 and June 2016, before and after institution of the MOU. Variables collected included the length of stay, patient age, seizure semiology, use of invasive monitoring, and site of surgery as well as the monthly number of single-surgery cases, complex cases (i.e., staged surgeries), and overall number of surgery cases. RESULTS Over the 46 months of the study, a total of 104 patients underwent a total of 200 operations; 71 operations were performed in 39 patients during the pre-MOU period (28 months) and 129 operations were performed in 200 patients during the post-MOU period (18 months). There was a significant difference in the use of invasive monitoring, the site of surgery, the final therapy, and the type of insurance. The number of single-surgery cases, complex-surgery cases, and the overall number of cases increased significantly. CONCLUSIONS Partnerships with outside epilepsy centers are a means to increase access to surgical care. These partnerships are likely reproducible, can be mutually beneficial to all centers involved, and ultimately improve patient access to care.

Disconnection of the pathological connectome for multifocal epilepsy surgery

OBJECTIVERecent neuroimaging studies suggest that intractable epilepsy involves pathological functional networks as well as strong epileptogenic foci. Combining cortico-cortical evoked potential (CCEP) recording and tractography is a useful strategy for mapping functional connectivity in normal and pathological networks. In this study, the authors sought to demonstrate the efficacy of preoperative combined CCEP recording, high gamma activity (HGA) mapping, and tractography for surgical planning, and of intraoperative CCEP measures for confirmation of selective pathological network disconnection.METHODSThe authors treated 4 cases of intractable epilepsy. Diffusion tensor imaging-based tractography data were acquired before the first surgery for subdural grid implantation. HGA and CCEP investigations were done after the first surgery, before the second surgery was performed to resect epileptogenic foci, with continuous CCEP monitoring during resection.RESULTSAll 4 patients in this report had measurable pathological CCEPs. The mean negative peak-1 latency of normal CCEPs related to language functions was 22.2 ± 3.5 msec, whereas pathological CCEP latencies varied between 18.1 and 22.4 msec. Pathological CCEPs diminished after complete disconnection in all cases. At last follow-up, all of the patients were in long-term postoperative seizure-free status, although 1 patient still suffered from visual aura every other month.CONCLUSIONSCombined CCEP measurement, HGA mapping, and tractography greatly facilitated targeted disconnection of pathological networks in this study. Although CCEP recording requires technical expertise, it allows for assessment of pathological network involvement in intractable epilepsy and may improve seizure outcome.

Phenytoin versus levetiracetam as prophylaxis for postcraniotomy seizure in patients with no history of seizures: systematic review and meta-analysis

OBJECTIVEDe novo seizure following craniotomy (DSC) for nontraumatic pathology may adversely affect medical and neurological outcomes in patients with no history of seizures who have undergone craniotomies. Antiepileptic drugs (AEDs) are commonly used prophylactically in patients undergoing craniotomy; however, evidence supporting this practice is limited and mixed. The authors aimed to collate the available evidence on the efficacy and tolerability of levetiracetam monotherapy and compare it with that of the classic AED, phenytoin, for DSC.METHODSPubMed, Embase, Web of Science, and the Cochrane Library were searched for studies that compared levetiracetam with phenytoin for DSC prevention. Inclusion criteria were adult patients with no history of epilepsy who underwent craniotomy with prophylactic usage of phenytoin, a comparator group with levetiracetam treatment as the main treatment difference between the two groups, and availability of data on the numbers of patients and seizures for each group. Patients with brain injury and previous seizure history were excluded. DSC occurrence and adverse drug reaction (ADR) were evaluated. Seizure occurrence was calculated using the Peto odds ratio (POR), which is the relative effect estimation method of choice for binary data with rare events.RESULTSData from 7 studies involving 803 patients were included. The DSC occurrence rate was 1.26% (4/318) in the levetiracetam cohort and 6.60% (32/485) in the phenytoin cohort. Meta-analysis showed that levetiracetam is significantly superior to phenytoin for DSC prevention (POR 0.233, 95% confidence interval [CI] 0.117-0.462, p < 0.001). Subgroup analysis demonstrated that levetiracetam is superior to phenytoin for DSC due to all brain diseases (POR 0.129, 95% CI 0.039-0.423, p = 0.001) and tumor (POR 0.282, 95% CI 0.117-0.678, p = 0.005). ADRs in the levetiracetam group were cognitive disturbance, thrombophlebitis, irritability, lethargy, tiredness, and asthenia, whereas rash, anaphylaxis, arrhythmia, and hyponatremia were more common in the phenytoin group. The overall occurrence of ADR in the phenytoin (34/466) and levetiracetam (26/432) groups (p = 0.44) demonstrated no statistically significant difference in ADR occurrence. However, the discontinuation rate of AEDs due to ADR was 53/297 in the phenytoin group and 6/196 in the levetiracetam group (POR 0.266, 95% CI 0.137-0.518, p < 0.001).CONCLUSIONSLevetiracetam is superior to phenytoin for DSC prevention for nontraumatic pathology and has fewer serious ADRs that lead to discontinuation. Further high-quality studies that compare levetiracetam with placebo are necessary to provide evidence for establishing AED guidelines.

Patterns of opioid use in patients with trigeminal neuralgia undergoing neurosurgery

OBJECTIVE

First-line treatment for trigeminal neuralgia (TN) is pharmacological management using antiepileptic drugs (AEDs), e.g., carbamazepine (CBZ) and oxcarbazepine (OCBZ). Surgical intervention has been shown to be an effective and durable treatment for TN that is refractory to medical therapy. Despite the lack of evidence for efficacy in patients with TN, the authors hypothesized that patients with neuropathic facial pain are prescribed opioids at high rates, and that neurosurgical intervention may lead to a reduction in opioid use.

METHODS

This is a retrospective study of patients with facial pain seen by a single neurosurgeon. All patients completed a survey on pain medications, medical comorbidities, prior interventions for facial pain, and a validated pain outcome tool (the Penn Facial Pain Scale). Patients subsequently undergoing neurosurgical intervention completed a survey at the 1-month follow-up in the office, in addition to telephone interviews using a standardized script between 1 and 6 years after intervention. Univariate and multivariate logistic regression were used to predict opioid use.

RESULTS

The study cohort consisted of 309 patients (70% Burchiel type 1 TN [TN1], 18% Burchiel type 2 [TN2], 6% atypical facial pain [AFP], and 6% TN secondary to multiple sclerosis [TN-MS]). At initial presentation, 20% of patients were taking opioids. Of these patients, 55% were receiving concurrent opioid therapy with CBZ/OCBZ, and 84% were receiving concurrent therapy with at least one type of AED. Facial pain diagnosis (for diagnoses other than TN1, odds ratio [OR] 2.5, p = 0.01) and facial pain intensity at its worst (for each unit increase, OR 1.4, p = 0.005) were predictors of opioid use at baseline. Neurosurgical intervention led to a reduction in opioid use to 8% at long-term follow-up (p < 0.01, Fisher's exact test; n = 154). Diagnosis (for diagnoses other than TN1, OR 4.7, p = 0.002) and postintervention reduction in pain at its worst (for each unit reduction, OR 0.8, p < 10-3) were predictors of opioid use at long-term follow-up. On subgroup analysis, patients with TN1 demonstrated a decrease in opioid use to 5% at long-term follow-up (p < 0.05, Fisher's exact test), whereas patients with non-TN1 facial pain did not. In the nonsurgical group, there was no statistically significant decrease in opioid use at long-term follow-up (n = 81).

CONCLUSIONS

In spite of its high potential for abuse, opioid use, mostly as an adjunct to AEDs, is prevalent in patients with facial pain. Opportunities to curb opioid use in TN1 include earlier neurosurgical intervention.

Seizure control after radiosurgery for cerebral arteriovenous malformations: a 25-year experience

OBJECTIVE

Seizures are the second-most common presenting symptom in patients with lobar arteriovenous malformations (AVMs). However, few studies have assessed the long-term effect of stereotactic radiosurgery (SRS) on seizure control. The authors of this study assess the outcome of SRS for these patients to identify prognostic factors associated with seizure control.

METHODS

Patients with AVM who presented with a history of seizure and underwent SRS at the authors' institution between 1987 and 2012 were retrospectively assessed. The total cohort included 155 patients with a mean follow-up of 86 months (range 6-295 months). Primary outcomes assessed were seizure frequency, antiepileptic drug regimen, and seizure freedom for 6 months prior to last follow-up.

RESULTS

Seizure-free status was achieved in 108 patients (70%), with an additional 23 patients (15%) reporting improved seizure frequency as compared to their pre-SRS status. The median time to seizure-free status was estimated to be 12 months (95% CI 0-27 months) as evaluated via Kaplan-Meier survival analysis. The mean seizure frequency prior to SRS was 14.2 (95% CI 5.4-23.1) episodes per year. Although not all patients tried, the proportion of patients successfully weaned off all antiepileptic drugs was 18% (28/155 patients). On multivariate logistic regression, focal impaired awareness seizure type (also known as complex partial seizures) and superficial venous drainage were significantly associated with a decreased odds ratio for seizure-free status at last follow-up (OR 0.37 [95% CI 0.15-0.92] for focal impaired awareness seizures; OR 0.36 [95% CI 0.16-0.81] for superficial venous drainage). The effects of superficial venous drainage on seizure outcome were nonsignificant when excluding patients with < 2 years of follow-up. AVM obliteration did not correlate with long-term seizure freedom (p = 0.202, chi-square test).

CONCLUSIONS

This study suggests that SRS improves long-term seizure control and increases the likelihood of being medication free, independently of AVM obliteration. Patients with focal impaired awareness seizures were less likely to obtain long-term seizure relief.

Robot-assisted stereoelectroencephalography in children

OBJECTIVEThe goal in the study was to describe the clinical outcomes associated with robot-assisted stereoelectroencephalography (SEEG) in children.METHODSThe authors performed a retrospective, single-center study in consecutive children with medically refractory epilepsy who were undergoing robot-assisted SEEG. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom. Both univariate and multivariate methods were used to analyze the preoperative and operative factors associated with seizure freedom.RESULTSFifty-seven children underwent a total of 64 robot-assisted procedures. The patients' mean age was 12 years, an average of 6.4 antiepileptic drugs (AEDs) per patient had failed prior to implantation, and in 56% of the patients the disease was considered nonlesional. On average, children had 12.4 electrodes placed per implantation, with an implantation time of 9.6 minutes per electrode and a 10-day postoperative stay. SEEG analysis yielded a definable epileptogenic zone in 51 (89%) patients; 42 (74%) patients underwent surgery, half of whom were seizure free at last follow-up, 19.6 months from resection. In a multivariate generalized linear model, resective surgery, older age, and shorter SEEG-related hospital length of stay were associated with seizure freedom. In a Cox proportional hazards model including only the children who underwent resective surgery, older age was the only significant factor associated with seizure freedom. Complications related to bleeding were the major contributors to morbidity. One patient (1.5%) had a symptomatic hemorrhage resulting in a permanent neurological deficit.CONCLUSIONSThe authors report one of the largest pediatric-specific SEEG series demonstrating that the modern surgical management of medically refractory epilepsy in children can lead to seizure freedom in many patients, while also highlighting the challenges posed by this difficult patient population.

Nationwide incidence and risk factors for posttraumatic seizures in children with traumatic brain injury

OBJECTIVEPosttraumatic seizures (PTSs) are the most common complication following a traumatic brain injury (TBI) and may lead to posttraumatic epilepsy. PTS is well described in the adult literature but has not been studied extensively in children. Here, the authors utilized the largest nationwide registry of pediatric hospitalizations to report the national incidence, risk factors, and outcomes associated with PTS in pediatric TBI.METHODSThe authors queried the Kids' Inpatient Database (KID) using ICD-9-CM codes to identify all patients (age < 21 years) who had a primary diagnosis of TBI (850.xx-854.xx) and a secondary diagnosis of PTS (780.33, 780.39). Parameters of interest included patient demographics, preexisting comorbidities, hospital characteristics, nature of injury (open/closed), injury type (concussion, laceration/contusion, subarachnoid hemorrhage, subdural hematoma, or epidural hematoma), loss of consciousness (LOC), surgical management (Clinical Classification Software code 1 or 2), discharge disposition, in-hospital complications, and in-hospital mortality. The authors utilized the IBM SPSS statistical package (version 24) for univariate comparisons, as well as the identification of independent risk factors for PTS in multivariable analysis (alpha set at < 0.05).RESULTSThe rate of PTS was 6.9% among 124,444 unique patients hospitalized for TBI. The utilization rate of continuous electroencephalography (cEEG) was 0.3% and increased between 2003 (0.1%) and 2012 (0.7%). The most common etiologies of TBI were motor vehicle accident (n = 50,615), accidental fall (n = 30,847), and blunt trauma (n = 13,831). However, the groups with the highest rate of PTS were shaken infant syndrome (41.4%), accidental falls (8.1%), and cycling accidents (7.4%). In multivariable analysis, risk factors for PTS included age 0-5 years (compared with 6-10, 11-15, and 16-20 years), African American race (OR 1.4), ≥ 3 preexisting comorbidities (OR 4.0), shaken infant syndrome (OR 4.4), subdural hematoma (OR 1.6), closed-type injury (OR 2.3), brief LOC (OR 1.4), moderate LOC (OR 1.5), and prolonged LOC with baseline return (OR 1.8). Surgically managed patients were more likely to experience PTS (OR 1.5) unless they were treated within 24 hours of admission (OR 0.8). PTS was associated with an increased likelihood of in-hospital complications (OR 1.7) and adverse (nonroutine) discharge disposition (OR 1.2), but not in-hospital mortality (OR 0.5). The overall utilization rate of cEEG was 1.3% in PTS patients compared with 0.2% in patients without PTS. Continuous EEG monitoring was associated with higher rates of diagnosed PTS (35.4% vs 6.8%; OR 4.9, p < 0.001).CONCLUSIONSPTS is common in children with TBI and is associated with adverse outcomes. Independent risk factors for PTS include younger age (< 5 years), African American race, increased preexisting comorbidity, prolonged LOC, and injury pattern involving cortical exposure to blood products. However, patients who undergo urgent surgical evacuation are less likely to develop PTS.

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.

Hippocampal transection for stereo-electroencephalography-proven dominant mesial temporal lobe epilepsy in a child: a detailed case report and critical review

Resection of the hippocampus ipsilateral to the verbal memory-dominant hemisphere frequently results in severe memory deficits. In adults with epilepsy, multiple hippocampal transections (MHTs) have resulted in excellent seizure outcome with preservation of verbal memory. The authors report the first detailed case of a child undergoing MHTs for mesial temporal lobe epilepsy. A 13-year-old right-handed boy had intractable seizures characterized by epigastric discomfort evolving to unresponsiveness and chewing automatisms, lasting 1 minute and occurring 2-3 times weekly, sometimes ending in a generalized tonic-clonic seizure. He had no seizure risk factors and nonfocal examination results. Interictal electroencephalography (EEG) showed frequent left temporal epileptiform discharges (maximum FT9) and intermittent slowing. Video EEG, FDG-PET, and 1.5-T MRI were nonlocalizing. Neuropsychological evaluation suggested left temporal lobe dysfunction. A stereo-EEG investigation using 8 electrodes localized the seizure onset zone to the anterior mesial temporal region, immediately involving the hippocampus. The temporal pole and amygdala were resected en bloc with 3 MHTs. Comparison of neuropsychological tests 4 months before and 6 months after the surgery showed a significant decline only in confrontational naming and no significant change in verbal memory. Six and a half years later, the patient remains seizure free with no antiepileptic drugs. In children with established hemispheric dominance suffering from mesial temporal lobe epilepsy, MHTs may be an option.

Stereotactic laser ablation for nonlesional cingulate epilepsy: case report

Stereotactic laser ablation (SLA) is being increasingly used to treat refractory focal epilepsy, especially mesial temporal lobe epilepsy. However, emerging evidence suggests it can be used for extratemporal lobe epilepsy as well.The authors report the case of a 17-year-old male who presented with refractory nocturnal seizures characterized by bilateral arms stiffening or rhythmic jerking lasting several seconds. Semiology suggested an epileptogenic zone close to one of the supplementary sensory motor areas. Electroencephalography showed seizures arising from the central region without consistent lateralization. Brain imaging showed no abnormality. An invasive evaluation using bilateral stereoelectroencephalography (SEEG) was utilized in 2 steps, first to establish the laterality of seizures, and second to further cover the mesial cingulate region of the right hemisphere. Seizures arose from the middle portion of the right cingulate gyrus. Extraoperative electrical mapping revealed that the seizure onset zone was adjacent to eloquent motor areas. SLA targeting the right midcingulate gyrus was performed. The patient has remained seizure free since immediately after the procedure with no postoperative deficits (follow-up of 17 months).This case highlights the utility of SEEG in evaluating difficult-to-localize, focal epilepsy. It also demonstrates that the use of SLA can be extended to nonlesional, extratemporal epilepsies.

Results of volume-staged fractionated Gamma Knife radiosurgery for large complex arteriovenous malformations: obliteration rates and clinical outcomes of an evolving treatment paradigm

OBJECTIVE There are few reported series regarding volume-staged Gamma Knife radiosurgery (GKRS) for the treatment of large, complex, cerebral arteriovenous malformations (AVMs). The object of this study was to report the results of using volume-staged Gamma Knife radiosurgery for patients affected by large and complex AVMs. METHODS Data from 20 patients with large AVMs were prospectively included in the authors' AVM database between 2004 and 2012. A staging strategy was used when treating lesion volumes larger than 10 cm³. Hemorrhage and seizures were the presenting clinical feature for 6 (30%) and 8 (40%) patients, respectively. The median AVM volume was 15.9 cm³ (range 10.1-34.3 cm³). The mean interval between stages (± standard deviation) was 15 months (± 9 months). The median margin dose for each stage was 20 Gy (range 18-25 Gy). RESULTS Obliteration was confirmed in 8 (42%) patients after a mean follow-up of 45 months (range 19-87 months). A significant reduction (> 75%) of the original nidal volume was achieved in 4 (20%) patients. Engel Class I-II seizure status was reported by 75% of patients presenting with seizures (50% Engel Class I and 25% Engel Class II) after radiosurgery. After radiosurgery, 71.5% (5/7) of patients who had presented with a worsening neurological deficit reported a complete resolution or amelioration. None of the patients who presented acutely because of hemorrhage experienced a new bleeding episode during follow-up. One (5%) patient developed radionecrosis that caused sensorimotor hemisyndrome. Two (10%) patients sustained a bleeding episode after GKRS, although only 1 (5%) was symptomatic. High nidal flow rate and a time interval between stages of less than 11.7 months were factors significantly associated with AVM obliteration (p = 0.021 and p = 0.041, respectively). Patient age younger than 44 years was significantly associated with a greater than 75% reduction in AVM volume but not with AVM obliteration (p = 0.024). CONCLUSIONS According to the results of this study, volume-staged GKRS is an effective and safe treatment strategy for large, complex, cerebral AVMs for which microsurgery or endovascular approaches could carry substantially higher risks to the patient. Radiation doses up to 20 Gy can be safely administered. The time interval between stages should be shorter than 11.7 months to increase the chance of obliteration. High nidal flow and a patient age younger than 44 years were factors associated with nidus obliteration and significant nidus reduction, respectively.

Brain invasion and the risk of seizures in patients with meningioma

OBJECTIVE

Identification of risk factors for perioperative epilepsy remains crucial in the care of patients with meningioma. Moreover, associations of brain invasion with clinical and radiological variables have been largely unexplored. The authors hypothesized that invasion of the cortex and subsequent increased edema facilitate seizures, and they compared radiological data and perioperative seizures in patients with brain-invasive or noninvasive meningioma.

METHODS

Correlations of brain invasion with tumor and edema volumes and preoperative and postoperative seizures were analyzed in univariate and multivariate analyses.

RESULTS

Totals of 108 (61%) females and 68 (39%) males with a median age of 60 years and harboring totals of 92 (52%) grade I, 79 (45%) grade II, and 5 (3%) grade III tumors were included. Brain invasion was found in 38 (22%) patients and was absent in 138 (78%) patients. The tumors were located at the convexity in 72 (41%) patients, at the falx cerebri in 26 (15%), at the skull base in 69 (39%), in the posterior fossa in 7 (4%), and in the ventricle in 2 (1%); the median tumor and edema volumes were 13.73 cm3 (range 0.81-162.22 cm3) and 1.38 cm3 (range 0.00-355.80 cm3), respectively. As expected, edema volume increased with rising tumor volume (p < 0.001). Brain invasion was independent of tumor volume (p = 0.176) but strongly correlated with edema volume (p < 0.001). The mean edema volume in noninvasive tumors was 33.0 cm3, but in invasive tumors, it was 130.7 cm3 (p = 0.008). The frequency of preoperative seizures was independent of the patients' age, sex, and tumor location; however, the frequency was 32% (n = 12) in patients with invasive meningioma and 15% (n = 21) in those with noninvasive meningioma (p = 0.033). In contrast, the probability of detecting brain invasion microscopically was increased more than 2-fold in patients with a history of preoperative seizures (OR 2.57, 95% CI 1.13-5.88; p = 0.025). In univariate analyses, the rate of preoperative seizures correlated slightly with tumor volume (p = 0.049) but strongly with edema volume (p = 0.014), whereas seizure semiology was found to be independent of brain invasion (p = 0.211). In multivariate analyses adjusted for age, sex, tumor location, tumor and edema volumes, and WHO grade, rising tumor volume (OR 1.02, 95% CI 1.00-1.03; p = 0.042) and especially brain invasion (OR 5.26, 95% CI 1.52-18.15; p = 0.009) were identified as independent predictors of preoperative seizures. Nine (5%) patients developed new seizures within a median follow-up time of 15 months after surgery. Development of postoperative epilepsy was independent of all clinical variables, including Simpson grade (p = 0.133), tumor location (p = 0.936), brain invasion (p = 0.408), and preoperative edema volume (p = 0.081), but was correlated with increasing preoperative tumor volume (p = 0.004). Postoperative seizure-free rates were similar among patients with invasive and those with noninvasive meningioma (p = 0.372).

CONCLUSIONS

Brain invasion was identified as a new and strong predictor for preoperative, but not postoperative, seizures. Although also associated with increased peritumoral edema, seizures in patients with invasive meningioma might be facilitated substantially by cortical invasion itself. Consideration of seizures in consultations between the neurosurgeon and neuropathologist can improve the microscopic detection of brain invasion.

Treatment of medically refractory seizures with responsive neurostimulation: 2 pediatric cases

The responsive neurostimulation (RNS) system, an adjunctive treatment for pharmacoresistant partial-onset seizures with 1 or 2 foci, has been available to patients aged 18 years or older since the device's FDA approval in 2013. Herein, the authors describe their off-label application of this technology in 2 pediatric patients and the consequent therapeutic benefit without surgical complications or treatment side effects. A 14-year-old nonambulatory, nonverbal male with severe developmental delay was considered for RNS therapy for medically and surgically refractory epilepsy with bilateral seizure onsets in the setting of a normal radiological examination and a known neuropathological diagnosis of type I cortical dysplasia. The RNS system was implanted with strip electrodes placed on the left lateral frontal and right lateral temporal neocortex. At 19 months' follow-up, cortical stimulation resulted in sustained reduction in both seizure frequency-3 seizures per day down from 15 to 30 per day-and seizure severity. The patient subsequently underwent a trial of corticothalamic stimulation with a right temporal cortical strip and a left thalamic depth electrode, which resulted in a further 50% reduction in seizure frequency. In a second case, a 9-year-old right-handed female with radiological evidence of a small watershed infarct on the left and medically refractory seizures was referred for presurgical evaluation. Invasive monitoring revealed an unresectable seizure focus in the eloquent cortex of the left posterior frontal and parietal lobes. The RNS device was implanted with cortical leads placed at the putative seizure focus. At 21 months after surgery, the patient had been seizure free for 4 months, following a 17-month period in which the seizure frequency had decreased from 12 per month to 2 per month, with associated functional and behavioral improvement. The authors' results suggest that RNS may be a palliative option for children with intractable seizures whose condition warrants off-label use of the surgical device. The improved therapeutic effect noted with time and sustained RNS treatment points to a possible neuromodulatory effect.

Effectiveness of perioperative antiepileptic drug prophylaxis for early and late seizures following oncologic neurosurgery: a meta-analysis

OBJECTIVEThe purpose of this meta-analysis was to evaluate the impact of perioperative antiepileptic drug (AED) prophylaxis on short- and long-term seizure incidence among patients undergoing brain tumor surgery. It is the first meta-analysis to focus exclusively on perioperative AED prophylaxis among patients undergoing brain tumor surgery.METHODSThe authors searched PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials, clinicaltrials.gov, and the System for Information on Gray Literature in Europe for records related to perioperative AED prophylaxis for patients with brain tumors. Risk of bias in the included studies was assessed using the Cochrane risk of bias tool. Incidence rates for early seizures (within the first postoperative week) and total seizures were estimated based on data from randomized controlled trials. A Mantel-Haenszel random-effects model was used to analyze pooled relative risk (RR) of early seizures (within the first postoperative week) and total seizures associated with perioperative AED prophylaxis versus control.RESULTSFour RCTs involving 352 patients met the criteria of inclusion. The results demonstrated that perioperative AED prophylaxis for patients undergoing brain tumor surgery provides a statistically significant reduction in risk of early postoperative seizures compared with control (RR = 0.352, 95% confidence interval 0.130-0.949, p = 0.039). AED prophylaxis had no statistically significant effect on the total (combined short- and long-term) incidence of seizures.CONCLUSIONSThis meta-analysis demonstrates for the first time that perioperative AED prophylaxis for brain tumor surgery provides a statistically significant reduction in early postoperative seizure risk.

Magnetic resonance imaging-guided laser interstitial thermal therapy as treatment for intractable insular epilepsy in children

OBJECTIVE Seizure onset within the insula is increasingly recognized as a cause of intractable epilepsy. Surgery within the insula is difficult, with considerable risks, given the rich vascular supply and location near critical cortex. MRI-guided laser interstitial thermal therapy (LiTT) provides an attractive treatment option for insular epilepsy, allowing direct ablation of abnormal tissue while sparing nearby normal cortex. Herein, the authors describe their experience using this technique in a large cohort of children undergoing treatment of intractable localization-related epilepsy of insular onset. METHODS The combined epilepsy surgery database of Cook Children's Medical Center and Dell Children's Hospital was queried for all cases of insular onset epilepsy treated with LiTT. Patients without at least 6 months of follow-up data and cases preoperatively designated as palliative were excluded. Patient demographics, presurgical evaluation, surgical plan, and outcome were collected from patient charts and described. RESULTS Twenty patients (mean age 12.8 years, range 6.1-18.6 years) underwent a total of 24 LiTT procedures; 70% of these patients had normal findings on MRI. Patients underwent a mean follow-up of 20.4 months after their last surgery (range 7-39 months), with 10 (50%) in Engel Class I, 1 (5%) in Engel Class II, 5 (25%) in Engel Class III, and 4 (20%) in Engel Class IV at last follow-up. Patients were discharged within 24 hours of the procedure in 15 (63%) cases, in 48 hours in 6 (24%) cases, and in more than 48 hours in the remaining cases. Adverse functional effects were experienced following 7 (29%) of the procedures: mild hemiparesis after 6 procedures (all patients experienced complete resolution or had minimal residual dysfunction by 6 months), and expressive language dysfunction after 1 procedure (resolved by 3 months). CONCLUSIONS To their knowledge, the authors present the largest cohort of pediatric patients undergoing insular surgery for treatment of intractable epilepsy. The patient outcomes suggest that LiTT can successfully treat intractable seizures originating within the insula and offers an attractive alternative to open resection. This is the first description of LiTT applied to insular epilepsy and represents one of only a few series describing the use of LiTT in children. The results indicate that seizure reduction after LiTT compares favorably to that after conventional open surgical techniques.

Resting-state functional magnetic resonance imaging for surgical planning in pediatric patients: a preliminary experience

OBJECTIVE Cerebral mapping for surgical planning and operative guidance is a challenging task in neurosurgery. Pediatric patients are often poor candidates for many modern mapping techniques because of inability to cooperate due to their immature age, cognitive deficits, or other factors. Resting-state functional MRI (rs-fMRI) is uniquely suited to benefit pediatric patients because it is inherently noninvasive and does not require task performance or significant cooperation. Recent advances in the field have made mapping cerebral networks possible on an individual basis for use in clinical decision making. The authors present their initial experience translating rs-fMRI into clinical practice for surgical planning in pediatric patients. METHODS The authors retrospectively reviewed cases in which the rs-fMRI analysis technique was used prior to craniotomy in pediatric patients undergoing surgery in their institution. Resting-state analysis was performed using a previously trained machine-learning algorithm for identification of resting-state networks on an individual basis. Network maps were uploaded to the clinical imaging and surgical navigation systems. Patient demographic and clinical characteristics, including need for sedation during imaging and use of task-based fMRI, were also recorded. RESULTS Twenty patients underwent rs-fMRI prior to craniotomy between December 2013 and June 2016. Their ages ranged from 1.9 to 18.4 years, and 12 were male. Five of the 20 patients also underwent task-based fMRI and one underwent awake craniotomy. Six patients required sedation to tolerate MRI acquisition, including resting-state sequences. Exemplar cases are presented including anatomical and resting-state functional imaging. CONCLUSIONS Resting-state fMRI is a rapidly advancing field of study allowing for whole brain analysis by a noninvasive modality. It is applicable to a wide range of patients and effective even under general anesthesia. The nature of resting-state analysis precludes any need for task cooperation. These features make rs-fMRI an ideal technology for cerebral mapping in pediatric neurosurgical patients. This review of the use of rs-fMRI mapping in an initial pediatric case series demonstrates the feasibility of utilizing this technique in pediatric neurosurgical patients. The preliminary experience presented here is a first step in translating this technique to a broader clinical practice.

Relationship between cortical resection and visual function after occipital lobe epilepsy surgery

OBJECTIVE In this study, the authors investigated long-term clinical and visual outcomes of patients after occipital lobe epilepsy (OLE) surgery and analyzed the relationship between visual cortical resection and visual function after OLE surgery. METHODS A total of 42 consecutive patients who were diagnosed with OLE and underwent occipital lobe resection between June 1995 and November 2013 were included. Clinical, radiological, and histopathological data were reviewed retrospectively. Seizure outcomes were categorized according to the Engel classification. Visual function after surgery was assessed using the National Eye Institute Visual Functioning Questionnaire 25. The relationship between the resected area of the visual cortex and visual function was demonstrated by multivariate linear regression models. RESULTS After a mean follow-up period of 102.2 months, 27 (64.3%) patients were seizure free, and 6 (14.3%) patients had an Engel Class II outcome. Nineteen (57.6%) of 33 patients had a normal visual field or quadrantanopia after surgery (normal and quadrantanopia groups). Patients in the normal and quadrantanopia groups had better vision-related quality of life than those in the hemianopsia group. The resection of lateral occipital areas 1 and 2 of the occipital lobe was significantly associated with difficulties in general vision, peripheral vision, and vision-specific roles. In addition, the resection of intraparietal sulcus 3 or 4 was significantly associated with decreased social functioning. CONCLUSIONS The authors found a favorable seizure control rate (Engel Class I or II) of 78.6%, and 57.6% of the subjects had good visual function (normal vision or quadrantanopia) after OLE surgery. Lateral occipital cortical resection had a significant effect on visual function despite preservation of the visual field.

Mesial temporal lobe epilepsy: long-term seizure outcome of patients primarily treated with transsylvian selective amygdalohippocampectomy

OBJECTIVE The aim of this study was to present long-term seizure outcome data in a consecutive series of patients with refractory mesial temporal lobe epilepsy primarily treated with transsylvian selective amygdalohippocampectomy (SAHE). METHODS The authors retrospectively analyzed prospectively collected data for all patients who had undergone resective surgery for medically refractory epilepsy at their institution between July 1994 and December 2014. Seizure outcome was assessed according to the International League Against Epilepsy (ILAE) and the Engel classifications. RESULTS The authors performed an SAHE in 158 patients (78 males, 80 females; 73 right side, 85 left side) with a mean age of 37.1 ± 10.0 years at surgery. Four patients lost to follow-up and 1 patient who committed suicide were excluded from analysis. The mean follow-up period was 9.7 years. At the last available follow-up (or before reoperation), 68 patients (44.4%) had achieved an outcome classified as ILAE Class 1a, 46 patients (30.1%) Class 1, 6 patients (3.9%) Class 2, 16 patients (10.4%) Class 3, 15 patients (9.8%) Class 4, and 2 patients (1.3%) Class 5. These outcomes correspond to Engel Class I in 78.4% of the patients, Engel Class II in 10.5%, Engel Class III in 8.5%, and Engel Class IV in 2.0%. Eleven patients underwent a second surgery (anterior temporal lobectomy) after a mean of 4.4 years from the SAHE (left side in 6 patients, right side in 5). Eight (72.7%) of these 11 patients achieved seizure freedom. The overall ILEA seizure outcome since (re)operation after a mean follow-up of 10.0 years was Class 1a in 72 patients (47.0%), Class 1 in 50 patients (32.6%), Class 2 in 7 patients (4.6%), Class 3 in 15 patients (9.8%), Class 4 in 8 patients (5.2%), and Class 5 in 1 patient (0.6%). These outcomes correspond to an Engel Class I outcome in 84.3% of the patients. CONCLUSIONS A satisfactory long-term seizure outcome following transsylvian SAHE was demonstrated in a selected group of patients with refractory temporal lobe epilepsy.

Localization of musicogenic epilepsy to Heschl's gyrus and superior temporal plane: case report

Musicogenic epilepsy (ME) is an extremely rare form of the disorder that is provoked by listening to or playing music, and it has been localized to the temporal lobe. The number of reported cases of ME in which intracranial electroencephalography (iEEG) has been used for seizure focus localization is extremely small, especially with coverage of the superior temporal plane (STP) and specifically, Heschl's gyrus (HG). The authors describe the case of a 17-year-old boy with a history of medically intractable ME who underwent iEEG monitoring that involved significant frontotemporal coverage as well as coverage of the STP with an HG depth electrode anteriorly and a planum temporale depth electrode posteriorly. Five seizures occurred during the monitoring period, and a seizure onset zone was localized to HG and the STP. The patient subsequently underwent right temporal neocortical resection, involving the STP and including HG, with preservation of the mesial temporal structures. The patient remains seizure free 1 year postoperatively. To the authors' knowledge, this is the first reported case of ME in which the seizure focus has been localized to HG and the STP with iEEG monitoring. The authors review the literature on iEEG findings in ME, explain their approach to HG depth electrode placement, and discuss the utility of STP depth electrodes in temporal lobe epilepsy.

Reoperation after failed resective epilepsy surgery in children

OBJECTIVE Although epilepsy surgery is an effective treatment option, at least 20%-40% of patients can continue to experience uncontrolled seizures resulting from incomplete resection of the lesion, epileptogenic zone, or secondary epileptogenesis. Reoperation could eliminate or improve seizures. Authors of this study evaluated outcomes following reoperation in a pediatric population. METHODS A retrospective single-center analysis of all patients who had undergone resective epilepsy surgery in the period from 2001 to 2013 was performed. After excluding children who had repeat hemispherotomy, there were 24 children who had undergone a second surgery and 2 children who had undergone a third surgery. All patients underwent MRI and video electroencephalography (VEEG) and 21 underwent magnetoencephalography (MEG) prior to reoperation. RESULTS The mean age at the first and second surgery was 7.66 (SD 4.11) and 10.67 (SD 4.02) years, respectively. The time between operations ranged from 0.03 to 9 years. At reoperation, 8 patients underwent extended cortical resection; 8, lobectomy; 5, lesionectomy; and 3, functional hemispherotomy. One year after reoperation, 58% of the children were completely seizure free (International League Against Epilepsy [ILAE] Class 1) and 75% had a reduction in seizures (ILAE Classes 1-4). Patients with MEG clustered dipoles were more likely to be seizure free than to have persistent seizures (71% vs 40%, p = 0.08). CONCLUSIONS Reoperation in children with recurrent seizures after the first epilepsy surgery could result in favorable seizure outcomes. Those with residual lesion after the first surgery should undergo complete resection of the lesion to improve seizure outcome. In addition to MRI and VEEG, MEG should be considered as part of the reevaluation prior to reoperation.

Posttraumatic epilepsy: long-term follow-up of children with mild traumatic brain injury

OBJECTIVE Posttraumatic epilepsy (PTE) is a known complication of traumatic brain injury (TBI). The true incidence of PTE in children is still uncertain, because most research has been based primarily on adults. This study aimed to determine the true incidence of PTE in a pediatric population with mild TBI (MTBI) and to identify risk factors for the development of epileptic events. METHODS Data were collected from electronic medical records of children 0-17 years of age, who were admitted to a single medical center between 2007 and 2009 with a diagnosis of MTBI. This prospective research consisted of a telephone survey between 2015 and 2016 of children or their caregivers, querying for information about epileptic episodes and current seizure and neurological status. The primary outcome measure was the incidence of epilepsy following TBI, which was defined as ≥ 2 unprovoked seizure episodes. Posttraumatic seizure (PTS) was defined as a single, nonrecurrent convulsive episode that occurred > 24 hours following injury. Seizures within 24 hours of the injury were defined as immediate PTS. RESULTS Of 290 children eligible for this study, 191 of them or their caregivers were reached by telephone survey and were included in the analysis. Most injuries (80.6%) were due to falls. Six children had immediate PTS. All children underwent CT imaging; of them, 72.8% demonstrated fractures and 10.5% did not demonstrate acute findings. The mean follow-up was 7.4 years. Seven children (3.7%) experienced PTS; of them, 6 (85.7%) developed epilepsy and 3 (42.9%) developed intractable epilepsy. The overall incidence of epilepsy and intractable epilepsy in this cohort was 3.1% and 1.6%, respectively. None of the children who had immediate PTS developed epilepsy. Children who developed epilepsy spent an average of 2 extra days in the hospital at the time of the injury. The mean time between trauma and onset of seizures was 3.1 years. Immediate PTS was not correlated with PTE. CONCLUSIONS In this analysis of data from medical records and long-term follow-up, MTBI was found to confer increased risk for the development of PTE and intractable PTE, of 4.5 and 8 times higher, respectively. As has been established in adults, these findings confirm that MTBI increases the risk for PTE in the pediatric population.

An extent of resection threshold for seizure freedom in patients with low-grade gliomas

OBJECTIVE Seizures are the most common presenting symptom of newly diagnosed WHO Grade II gliomas (low-grade glioma [LGG]) and significantly impair quality of life. Although gross-total resection of LGG is associated with better seizure control, it remains unclear whether an extent of resection (EOR) "threshold" exists for long-term seizure control. Specifically, what proportion of FLAIR-positive tissue in patients with newly diagnosed LGG must be removed to achieve Engel Class I seizure freedom? To clarify the EOR threshold for long-term seizure control, the authors analyzed data from a consecutive series of patients with newly diagnosed LGG who presented with seizures and subsequently underwent microsurgical resection. METHODS The authors identified consecutive patients with newly diagnosed LGG who presented with seizures and were treated at the Barrow Neurological Institute between 2002 and 2012. Patients were dichotomized into those who were seizure free postoperatively and those who were not. The EOR was calculated by quantitative comparison of pre- and postoperative MRI. Univariate analysis of these 2 groups included the chi-square test and the Mann-Whitney U-test, and a multivariate logistic regression was constructed to predict the impact of multiple independent variables on the likelihood of postoperative seizure freedom. To determine a threshold of EOR that optimizes seizure freedom, a receiver operating characteristic curve was plotted and the optimal point of discrimination was determined. RESULTS Data from 128 patients were analyzed (male/female ratio 1.37:1; mean age 40.8 years). All 128 patients presented with seizures, usually generalized (n = 57, 44.5%) or simple partial (n = 57, 44.5%). The median EOR was 90.0%. Of 128 patients, 46 (35.9%) had 100% volumetric tumor resection, 64 (50.0%) had 90%-99% volumetric tumor resection, and 11 (8.6%) had 80%-89% volumetric tumor resection. Postoperatively, 105 (82%) patients were seizure free (Engel Class I); 23 (18%) were not (Engel Classes II-IV). The proportion of seizure-free patients increased in proportion to the EOR. Predictive variables included in the regression model were preoperative Karnofsky Performance Scale score, seizure type, time from diagnosis to surgery, preoperative number of antiepileptic drugs, and EOR. Only EOR significantly affected the likelihood of postoperative Engel Class I status (OR 11.5, 95% CI 2.4-55.6; p = 0.002). The receiver operating characteristic curve generated based on Engel Class I status showed a sensitivity of 0.65 and 1 - specificity of 0.175, corresponding to an EOR of 80%. CONCLUSIONS For adult patients with LGG who suffer seizures, the results suggest that seizure freedom can be attained when EOR > 80% is achieved. Improvements in both the proportion of seizure-free patients and the durability of seizure freedom were observed beyond this 80% threshold. Interestingly, this putative EOR seizure-freedom threshold closely approximates that reported for the overall survival benefit in newly diagnosed hemispheric LGGs, suggesting that a minimum level of residual tumor burden is necessary for both disease and symptomatic progression.

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

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

Surgery guided with intraoperative electrocorticography in patients with low-grade glioma and refractory seizures

OBJECTIVE Using intraoperative electrocorticography (ECoG) to identify epileptogenic areas and improve postoperative seizure control in patients with low-grade gliomas (LGGs) remains inconclusive. In this study the authors retrospectively report on a surgery strategy that is based on intraoperative ECoG monitoring. METHODS A total of 108 patients with LGGs presenting at the onset of refractory seizures were included. Patients were divided into 2 groups. In Group I, all patients underwent gross-total resection (GTR) combined with resection of epilepsy areas guided by intraoperative ECoG, while patients in Group II underwent only GTR. Tumor location, tumor side, tumor size, seizure-onset features, seizure frequency, seizure duration, preoperative antiepileptic drug therapy, intraoperative electrophysiological monitoring, postoperative Engel class, and histological tumor type were compared between the 2 groups. RESULTS Univariate analysis demonstrated that tumor location and intraoperative ECoG monitoring correlated with seizure control. There were 30 temporal lobe tumors, 22 frontal lobe tumors, and 2 parietal lobe tumors in Group I, with 18, 24, and 12 tumors in those same lobes, respectively, in Group II (p < 0.05). In Group I, 74.07% of patients were completely seizure free (Engel Class I), while 38.89% in Group II (p < 0.05). In Group I, 96.30% of the patients achieved satisfactory postoperative seizure control (Engel Class I or II), compared with 77.78% in Group II (p < 0.05). Intraoperative ECoG monitoring indicated that in patients with temporal lobe tumors, most of the epileptic discharges (86.7%) were detected at the anterior part of the temporal lobe. In these patients with epilepsy discharges located at the anterior part of the temporal lobe, satisfactory postoperative seizure control (93.3%) was achieved after resection of the tumor and the anterior part of the temporal lobe. CONCLUSIONS Intraoperative ECoG monitoring provided the exact location of epileptogenic areas and significantly improved postoperative seizure control of LGGs. In patients with temporal lobe LGGs, resection of the anterior temporal lobe with epileptic discharges was sufficient to control seizures.

Stereotactic laser ablation for hypothalamic and deep intraventricular lesions

OBJECTIVE Laser ablation is a novel, minimally invasive procedure that utilizes MRI-guided thermal energy to treat epileptogenic and other brain lesions. In addition to treatment of mesial temporal lobe epilepsy, laser ablation is increasingly being used to target deep or inoperable lesions, including hypothalamic hamartoma (HH), subependymal giant cell astrocytoma (SEGA), and exophytic intrinsic hypothalamic/third ventricular tumors. The authors reviewed their early institutional experience with these patients to characterize clinical outcomes in patients undergoing this procedure. METHODS A retrospective cohort (n = 12) of patients undergoing laser ablation at a single institution was identified, and clinical and radiographic records were reviewed. RESULTS Laser ablation was successfully performed in all patients. No permanent neurological or endocrine complications occurred; 2 (17%) patients developed acute obstructive hydrocephalus or shunt malfunction following treatment. Laser ablation of HH resulted in seizure freedom (Engel Class I) in 67%, with the remaining patients having a clinically significant reduction in seizure frequency of greater than 90% compared with preoperative baseline (Engel Class IIB). Treatment of SEGAs resulted in durable clinical and radiographic tumor control in 2 of 3 cases, with one patient receiving adjuvant everolimus and the other receiving no additional therapy. Palliative ablation of hypothalamic/third ventricular tumors resulted in partial tumor control in 1 of 3 patients. CONCLUSIONS Early experience suggests that laser ablation is a generally safe, durable, and effective treatment for patients harboring HHs. It also appears effective for local control of SEGAs, especially in combination therapy with everolimus. Its use as a palliative treatment for intrinsic hypothalamic/deep intraventricular tumors was less successful and associated with a higher risk of serious complications. Additional experience and long-term follow-up will be beneficial in further characterizing the effectiveness and risk profile of laser ablation in treating these lesions in comparison with conventional resective surgery or stereotactic radiosurgery.

Epilepsy surgery in patients with autism

OBJECTIVE The purpose of this study was to report outcomes of epilepsy surgery in 56 consecutive patients with autism spectrum disorder. METHODS Medical records of 56 consecutive patients with autism who underwent epilepsy surgery were reviewed with regard to clinical characteristics, surgical management, postoperative seizure control, and behavioral changes. RESULTS Of the 56 patients with autism, 39 were male, 45 were severely autistic, 27 had a history of clinically significant levels of aggression and other disruptive behaviors, and 30 were considered nonverbal at baseline. Etiology of the epilepsy was known in 32 cases, and included structural lesions, medical history, and developmental and genetic factors. Twenty-nine patients underwent resective treatments (in 8 cases combined with palliative procedures), 24 patients had only palliative treatments, and 3 patients had only subdural electroencephalography. Eighteen of the 56 patients had more than one operation. The mean age at surgery was 11 ± 6.5 years (range 1.5-35 years). At a mean follow-up of 47 ± 30 months (range 2-117 months), seizure outcomes included 20 Engel Class I, 12 Engel Class II, 18 Engel Class III, and 3 Engel Class IV cases. The age and follow-up times are stated as the mean ± SD. Three patients were able to discontinue all antiepileptic drugs (AEDs). Aggression and other aberrant behaviors observed in the clinical setting improved in 24 patients. According to caregivers, most patients also experienced some degree of improvement in daily social and cognitive function. Three patients had no functional or behavioral changes associated with seizure reduction, and 2 patients experienced worsening of seizures and behavioral symptoms. CONCLUSIONS Epilepsy surgery in patients with autism is feasible, with no indication that the comorbidity of autism should preclude a good outcome. Resective and palliative treatments brought seizure freedom or seizure reduction to the majority of patients, although one-third of the patients in this study required more than one procedure to achieve worthwhile improvement in the long term, and few patients were able to discontinue all AEDs. The number of palliative procedures performed, the need for multiple interventions, and continued use of AEDs highlight the complex etiology of epilepsy in patients with autism spectrum disorder. These considerations underscore the need for continued analysis, review, and reporting of surgical outcomes in patients with autism, which may aid in better identification and management of surgical candidates. The reduction in aberrant behaviors observed in this series suggests that some behaviors previously attributed to autism may be associated with intractable epilepsy, and further highlights the need for systematic evaluation of the relationship between the symptoms of autism and refractory seizures.

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

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

Pediatric epilepsy surgery: could age be a predictor of outcomes?

OBJECTIVE Like adults, many children suffering from intractable seizures benefit from surgical therapy. Although various reports indicate that early intervention may avoid severe developmental consequences often associated with intractable epilepsy, surgery is still considered a last option for many children. In this retrospective study, the authors aimed to determine whether pediatric epilepsy surgery, in particular during the first years of life, relates to measurable benefits. METHODS Data from 78 patients (age range 5 months to 17 years) who underwent epilepsy surgery at the Geneva and Lausanne University Hospitals between 1997 and 2012 were reviewed retrospectively. Patients were dichotomized into 2 groups: infants (≤ 3 years of age, n = 19), and children/adolescents (4-17 years of age, n = 59). Compared with children/adolescents, infants more often had a diagnosis of dysplasia (37% vs 10%, respectively; p < 0.05, chi-square test). RESULTS The overall seizure-free rate was 76.9%, with 89.5% in infants and 72.9% in the children/adolescents group. Infants were 2.76 times as likely to achieve seizure-free status as children/adolescents. Postoperative antiepileptic medication was reduced in 67.9% of patients. Only 11.4% of the patients were taking more than 2 antiepileptic drugs after surgery, compared with 43% before surgery (p < 0.0001). The overall complication rate was 15.1% (6.4% transient hemiparesis), and no major complications or deaths occurred. CONCLUSIONS The data show a high seizure-free rate in children ≤ 3 years of age, despite a higher occurrence of dysplastic, potentially ill-defined lesions. Pediatric patients undergoing epilepsy surgery can expect a significant reduction in their need for medication. Given the excellent results in the infant group, prospective studies are warranted to determine whether age ≤ 3 years is a predictor for excellent surgical outcome.

Prophylactic antiepileptic drug administration following brain tumor resection: results of a recent AANS/CNS Section on Tumors survey

OBJECTIVE Antiepileptic drugs (AEDs) are often administered prophylactically following brain tumor resection. With conflicting evidence and unestablished guidelines, however, the nature of this practice among tumor surgeons is unknown. METHODS On November 24, 2015, a REDCap (Research Electronic Database Capture) survey was sent to members of the AANS/CNS Section on Tumors to query practice patterns. RESULTS Responses were received from 144 individuals, including 18.8% of board-certified neurosurgeons surveyed (across 86 institutions, 16 countries, and 5 continents). The majority reported practicing in an academic setting (85%) as a tumor specialist (71%). Sixty-three percent reported always or almost always prescribing AED prophylaxis postoperatively in patients with a supratentorial brain tumor without a prior seizure history. Meanwhile, 9% prescribed occasionally and 28% rarely prescribed AED prophylaxis. The most common agent was levetiracetam (85%). The duration of seizure prophylaxis varied widely: 25% of surgeons administered prophylaxis for 7 days, 16% for 2 weeks, 21% for 2 to 6 weeks, and 13% for longer than 6 weeks. Most surgeons (61%) believed that tumor pathology influences epileptogenicity, with high-grade glioma (39%), low-grade glioma (31%), and metastases (24%) carrying the greatest seizure risk. While the majority used prophylaxis, 62% did not believe or were unsure if prophylactic AEDs reduced seizures postoperatively. The vast majority (82%) stated that a well-designed randomized trial would help guide their future clinical decision making. CONCLUSIONS Wide knowledge and practice gaps exist regarding the frequency, duration, and setting of AED prophylaxis for seizure-naive patients undergoing brain tumor resection. Acceptance of universal practice guidelines on this topic is unlikely until higher-level evidence supporting or refuting the value of modern seizure prophylaxis is demonstrated.

Mild traumatic brain injury in children is associated with a low risk for posttraumatic seizures

OBJECT Of the 1.7 million traumatic brain injuries (TBIs) in the US, a third occur in patients under 14 years of age. The rate of posttraumatic epilepsy (PTE) may be as high as 19% after severe pediatric TBI, but the risk for seizures after mild TBI is unknown. Although the rate of seizures after mild TBI may be low, current practice is often driven by high clinical concern for posttraumatic seizures. In this study, the authors evaluated electroencephalography (EEG) results and antiepileptic drug (AED) use in a large cohort of children with mild TBI to estimate the incidence of posttraumatic seizures in this population. METHODS Patients presenting to Children's Hospital of Atlanta for mild TBI from 2010 to 2013 were evaluated. Five thousand one hundred forty-eight patients with mild TBI were studied and divided into 3 groups: 4168 who were discharged from the emergency department, 868 who were admitted without neurosurgical intervention, and 112 who underwent neurosurgical procedures (craniotomy for hematoma evacuation or elevation of depressed skull fractures) but were discharged without an extended stay. Demographic information, CT characteristics, EEG reports, and prescriptions for AEDs were analyzed. Long-term follow-up was sought for all patients who underwent EEG. Correlation between EEG result and AED use was also evaluated. RESULTS All patients underwent head CT, and admitted patients were more likely to have an abnormal study (p < 0.0001). EEG evaluations were performed for less than 1.0% of patients in all 3 categories, without significant differences between groups (p = 0.97). Clinicians prescribed AEDs in less than 2.0% of patients for all groups, without significant differences between groups (p = 0.094). Even fewer children continue to see a neurologist for long-term seizure management. The EEG result had good negative predictive value, but only an abnormal EEG reading that was diagnostic of seizures correlated significantly with AED prescription (p = 0.04). CONCLUSIONS EEG utilization and AED prescription was low in all 3 groups, indicating that seizures following mild TBI are likely rare events. EEG has good negative predictive value for patients who did not receive AEDs, but has poorer positive predictive value for AED use.

Resecting critical nodes from an epileptogenic circuit in refractory focal-onset epilepsy patients using subtraction ictal SPECT coregistered to MRI

OBJECTIVE The purpose of this study was to assess the positive predictive value of postresection outcomes obtained by presurgical subtracted ictal SPECT in patients with lesional (MRI positive) and nonlesional (MRI negative) refractory extratemporal lobe epilepsy (ETLE) and temporal lobe epilepsy (TLE). Specifically, outcomes were compared between partial versus complete resection of the regions of transient hyperperfusion identified using subtraction ictal SPECT coregistered to MRI (SISCOM) in relation to the ictal onset zone (IOZ) that was confirmed by electrocorticography (ECoG). That is, SISCOM was used to understand the long-term postsurgical outcomes following resection of the IOZ that overlapped with 1 or more regions of ictal onset-associated transient hyperperfusion. METHODS The study cohort included 44 consecutive patients with refractory ETLE or TLE who were treated between 2002 and 2013 and underwent presurgical evaluation using SISCOM. Concordance was determined between SISCOM localization and the IOZ on the basis of ECoG monitoring. In addition, the association between the extent of the resection site overlapping with the SISCOM signal and postresection outcomes were assessed. Postsurgical follow-up was longer than 24 months in 39 of 44 patients. RESULTS The dominant SISCOM signals were concordant with ECoG and overlapped the resection site in 32 of 44 (73%) patients (19 ETLE and 13 TLE patients), and 20 of 32 (63%) patients became seizure free. In all 19 ETLE patients with concordant SISCOM and ECoG results, the indicated location of ictal onset on ECoG was completely resected; 11 of 19 patients (58%) became seizure free (Engel Class I). In all 13 TLE patients with concordant SISCOM and ECoG results, the indicated ECoG focus was completely resected; 9 of 13 patients (69%) became seizure free (Engel Class I). Complete resection of the SISCOM signal was found in 7 of 34 patients (21%). Of these 7 patients, 5 patients (72%) were seizure free (Engel Class I). Partial resection of the SISCOM signal was found in 16 of 34 patients (47%), and 10 of these 16 patients (63%) were seizure free (Engel Class I) after more than 24 months of follow-up. CONCLUSIONS Concordance between 1 or more SISCOM regions of hyperperfusion with ECoG and at least partial resection of the dominant SISCOM signal in this refractory epilepsy cohort provided additional useful information for predicting long-term postresection outcomes. Such regions are likely critical nodes in more extensive, active, epileptogenic circuits. In addition, SPECT scanner technology may limit the sensitivity of meaningful SISCOM signals for identifying the maximal extent of the localizable epileptogenic network.

Perioperative seizure in patients with glioma is associated with longer hospitalization, higher readmission, and decreased overall survival

OBJECTIVE Seizures are among the most common perioperative complications in patients undergoing craniotomy for brain tumor resection and have been associated with increased disease progression and decreased survival. Little evidence exists regarding the relationship between postoperative seizures and hospital quality measures, including length of stay (LOS), disposition, and readmission. The authors sought to address these questions by analyzing a glioma population over 15 years. METHODS A retrospective cohort study was used to evaluate the outcomes of patients who experienced a postoperative seizure. Patients with glioma who underwent craniotomy for resection between 1998 and 2013 were enrolled in the institutional tumor registry. Basic data, including demographics and comorbidities, were recorded in addition to hospitalization details and complications. Seizures were diagnosed by clinical examination, observation, and electroencephalography. The Student t-test and chi-square test were used to analyze differences in the means between continuous and categorical variables, respectively. Multivariate logistic and linear regression was used to compare multiple clinical variables against hospital quality metrics and survival figures, respectively. RESULTS In total, 342 patients with glioma underwent craniotomy for first-time resection. The mean age was 51.0 ± 17.3 years, 192 (56.1%) patients were male, and the median survival time for all grades was 15.4 months (range 6.2-24.0 months). High-grade glioma (Grade III or IV) was seen in 71.9% of patients. Perioperative antiepileptic drugs were administered to 88% of patients. Eighteen (5.3%) patients experienced a seizure within 14 days postoperatively, and 9 (50%) of these patients experienced first-time seizures. The mean time to the first postoperative seizure was 4.3 days (range 0-13 days). There was no significant association between tumor grade and the rate of perioperative seizure (Grade I, 0%; II, 7.0%; III, 6.1%; IV, 5.2%; p = 0.665). A single ictal episode occurred in 11 patients, while 3 patients experienced 2 seizures and 4 patients developed 3 or more seizures. Compared with their seizure-free counterparts, patients who experienced a perioperative seizure had an increased average hospital (6.8 vs 3.6 days, p = 0.032) and ICU LOS (5.4 vs 2.3 days; p < 0.041). Seventy-five percent of seizure-free patients were discharged home in comparison with 55.6% of seizure patients (p = 0.068). Patients with a postoperative seizure were significantly more likely to visit the emergency department within 90 days (44.4% vs 19.0%; OR 3.41 [95% CI 1.29-9.02], p = 0.009) and more likely to be readmitted within 90 days (50.0% vs 18.4%; OR 4.45 [95% CI 1.69-11.70], p = 0.001). In addition, seizure-free patients had a longer median overall survival (15.6 months [interquartile range 6.6-24.4 months] vs 3.0 months [interquartile range 1.0-25.0 months]; p = 0.013). CONCLUSIONS Patients with perioperative seizures following glioma resection required longer hospital and ICU LOS, were readmitted at higher rates than seizure-free patients, and experienced shorter overall survival. Biological and clinical factors that predispose to the development of seizures after glioma surgery portend a worse outcome. Efforts to identify these factors and reduce the risk of postoperative seizure should remain a priority among neurosurgical oncologists.

Seizures in supratentorial meningioma: a systematic review and meta-analysis

OBJECT Meningioma is the most common benign intracranial tumor, and patients with supratentorial meningioma frequently suffer from seizures. The rates and predictors of seizures in patients with meningioma have been significantly under-studied, even in comparison with other brain tumor types. Improved strategies for the prediction, treatment, and prevention of seizures in patients with meningioma is an important goal, because tumor-related epilepsy significantly impacts patient quality of life. METHODS The authors performed a systematic review of PubMed for manuscripts published between January 1980 and September 2014, examining rates of pre- and postoperative seizures in supratentorial meningioma, and evaluating potential predictors of seizures with separate meta-analyses. RESULTS The authors identified 39 observational case series for inclusion in the study, but no controlled trials. Preoperative seizures were observed in 29.2% of 4709 patients with supratentorial meningioma, and were significantly predicted by male sex (OR 1.74, 95% CI 1.30-2.34); an absence of headache (OR 1.77, 95% CI 1.04-3.25); peritumoral edema (OR 7.48, 95% CI 6.13-9.47); and non-skull base location (OR 1.77, 95% CI 1.04-3.25). After surgery, seizure freedom was achieved in 69.3% of 703 patients with preoperative epilepsy, and was more than twice as likely in those without peritumoral edema, although an insufficient number of studies were available for formal meta-analysis of this association. Of 1085 individuals without preoperative epilepsy who underwent resection, new postoperative seizures were seen in 12.3% of patients. No difference in the rate of new postoperative seizures was observed with or without perioperative prophylactic anticonvulsants. CONCLUSIONS Seizures are common in supratentorial meningioma, particularly in tumors associated with brain edema, and seizure freedom is a critical treatment goal. Favorable seizure control can be achieved with resection, but evidence does not support routine use of prophylactic anticonvulsants in patients without seizures. Limitations associated with systematic review and meta-analysis should be considered when interpreting these results.

Epilepsy surgery related to pediatric brain tumors: Miami Children's Hospital experience

OBJECT

Pediatric brain tumors may be associated with medically intractable epilepsy for which surgery is indicated. The authors sought to evaluate the efficacy of epilepsy surgery for seizure control in pediatric patients with brain tumors.

METHODS

The authors performed a retrospective review of consecutive patients undergoing resective epilepsy surgery related to pediatric brain tumors at Miami Children's Hospital between June 1986 and June 2014. Time-to-event analysis for seizure recurrence was performed; an "event" was defined as any seizures that occurred following resective epilepsy surgery, not including seizures and auras in the 1st postoperative week. The authors analyzed several preoperative variables to determine their suitability to predict seizure recurrence following surgery.

RESULTS

Eighty-four patients (47 males) with a mean age (± standard deviation) of 8.7 ± 5.5 years (range 0.5-21.6 years) were included. The study included 39 (46%) patients with gliomas, 20 (24%) with dysembryoplastic neuroepithelial tumors (DNETs), 14 (17%) with gangliogliomas, and 11 (13%) with other etiologies. Among the patients with gliomas, 18 were classified with low-grade glioma, 5 had oligodendroglioma, 6 had uncategorized astrocytoma, 3 had pilocytic astrocytoma, 3 had pleomorphic xanthoastrocytoma, 3 had glioblastoma, and 1 had gliomatosis cerebri. Seventy-nine (94.0%) resections were guided by intraoperative electrocorticography (ECoG). The mean time (± standard deviation) to seizure recurrence was 81.8 ± 6.3 months. Engel Class I outcome was achieved in 66 (78%) and 63 (75%) patients at 1 and 2 years' follow-up, respectively. Patients with ganglioglioma demonstrated the highest probability of long-term seizure freedom, followed by patients with DNETs and gliomas. In univariate analyses, temporal location (HR 1.75, 95% CI 0.26-1.27, p = 0.171) and completeness of resection (HR 1.69, 95% CI 0.77-3.74, p = 0.191) demonstrated a trend toward a longer duration of seizure freedom.

CONCLUSIONS

ECoG-guided epilepsy surgery for pediatric patients with brain tumors is highly effective. Tumors located in the temporal lobe and those in which a complete ECoG-guided resection is performed may result in a greater likelihood of long-term seizure freedom.

Impact of epilepsy surgery on development of preschool children: identification of a cohort likely to benefit from early intervention

OBJECT

Outcomes of focal resection in young children with early-onset epilepsy are varied in the literature due to study differences. In this paper, the authors sought to define the effect of focal resection in a small homogeneous sample of children who were otherwise cognitively intact, but who required early surgical treatment. Preservation of and age-appropriate development of intelligence following focal resection was hypothesized.

METHODS

Cognitive outcome after focal resection was retrospectively reviewed for 15 cognitively intact children who were operated on at the ages of 2-6 years for lesion-related, early-onset epilepsy. Intelligence was tested prior to and after surgery. Effect sizes and confidence intervals for means and standard deviations were used to infer changes and differences in intelligence between 1) groups (pre vs post), 2) left versus right hemisphere resections, and 3) short versus long duration of seizures prior to resection.

RESULTS

No group changes from baseline occurred in Full Scale, verbal, or nonverbal IQ. No change from baseline intelligence occurred in children who underwent left or right hemisphere surgery, including no group effect on verbal scores following surgery in the dominant hemisphere. Patients with seizure durations of less than 6 months prior to resection showed improvement from their presurgical baseline in contrast to those with seizure duration of greater than 6 months prior to surgery, particularly in Wechsler Full Scale IQ and nonverbal intelligence.

CONCLUSIONS

This study suggests that surgical treatment of focal seizures in cognitively intact preschool children is likely to result in seizure remediation, antiepileptic drug discontinuation, and no significant decrement in intelligence. The latter finding is particularly significant in light of the longstanding concern associated with performing resections in the language-dominant hemisphere. Importantly, shorter seizure duration prior to resection can result in improved cognitive outcome, suggesting that surgery for this population should occur sooner to help improve intelligence outcomes.

Resection of cerebral gangliogliomas causing drug-resistant epilepsy: short- and long-term outcomes using intraoperative MRI and neuronavigation

OBJECT Cerebral gangliogliomas (GGs) are highly associated with intractable epilepsy. Incomplete resection due to proximity to eloquent brain regions or misinterpretation of the resection amount is a strong negative predictor for local tumor recurrence and persisting seizures. A potential method for dealing with this obstacle could be the application of intraoperative high-field MRI (iopMRI) combined with neuronavigation. METHODS Sixty-nine patients (31 female, 38 male; median age 28.5 ± 15.4 years) suffering from cerebral GGs were included in this retrospective study. Five patients received surgery twice in the observation period. In 48 of the 69 patients, 1.5-T iopMRI combined with neuronavigational guidance was used. Lesions close to eloquent brain areas were resected with the implementation of preoperative diffusion tensor imaging tractography and blood oxygenation level-dependent functional MRI (15 patients). RESULTS Overall, complete resection was accomplished in 60 of 69 surgical procedures (87%). Two patients underwent biopsy only, and in 7 patients, subtotal resection was accomplished because of proximity to critical brain areas. Excluding the 2 biopsies, complete resection using neuronavigation/iopMRI was documented in 33 of 46 cases (72%) by intraoperative imaging. Remnant tumor mass was identified intraoperatively in 13 of 46 patients (28%). After intraoperative second-look surgery, the authors improved the total resection rate by 9 patients (up to 91% [42 of 46]). Of 21 patients undergoing conventional surgery, 14 (67%) had complete resection without the use of iopMRI. Regarding epilepsy outcome, 42 of 60 patients with seizures (70%) became completely seizure free (Engel Class IA) after a median follow-up time of 55.5 ± 36.2 months. Neurological deficits were found temporarily in 1 (1.4%) patient and permanently in 4 (5.8%) patients. CONCLUSIONS Using iopMRI combined with neuronavigation in cerebral GG surgery, the authors raised the rate of complete resection in this series by 19%. Given the fact that total resection is a strong predictor of long-term seizure control, this technique may contribute to improved seizure outcome and reduced neurological morbidity.

Treatment of a cerebral pial arteriovenous fistula in a patient with sickle cell disease-related moyamoya syndrome: case report

Sickle cell disease (SCD) is an autosomal recessive hematological disorder, characterized by sickling of the red blood cells in response to a hypoxic stress and vaso-occlusive crises. It is associated with moyamoya-like changes on cerebral angiographic imaging in 43% of patients. Cerebral aneurysms, arteriovenous malformations, and dural arteriovenous fistulas (AVFs) have been described in association with SCD and moyamoya disease. However, the description of a pial AVF (pAVF) in a patient with SCD and/or moyamoya formation has not yet been reported. The authors present the case of a 15-year-old boy with SCD-associated moyamoya disease harboring a pAVF who developed a de novo venous aneurysm 8 months after undergoing indirect superficial temporal artery-middle cerebral artery (MCA) bypass that was complicated by bilateral ischemia of the MCA territory. The pAVF was successfully treated with transarterial embolization using Onyx. The authors describe the possible pathophysiological mechanisms and management strategies for this rare occurrence.

Gamma Knife radiosurgery for recurrent or residual seizures after anterior temporal lobectomy in mesial temporal lobe epilepsy patients with hippocampal sclerosis: long-term follow-up results of more than 4 years

OBJECT

Gamma Knife radiosurgery (GKRS) has proven efficacy in the treatment of drug-resistant mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and is comparable to conventional resective surgery. It may be effective as an alternative treatment to reoperation after failed temporal lobe surgery in patients with MTLE-HS. The purpose of this study was to investigate the efficacy of GKRS in patients with unilateral MTLE-HS who did not achieve seizure control or had recurrent seizures after anterior temporal lobectomy (ATL).

METHODS

Twelve patients (8 males; mean age 35.50 ± 9.90 years) with MTLE-HS who underwent GKRS after failed ATL (Engel Classes III-IV) were included. GKRS targets included the remnant tissue or adjacent regions of the previously performed ATL with a marginal dose of 24-25 Gy at the 50% isodose line in all patients. Final seizure outcome was assessed using Engel's modified criteria during the final 2 years preceding data analysis. A comparison between signal changes on follow-up MRI and clinical outcome was performed.

RESULTS

All patients were followed up for at least 4 years with a mean duration of 6.18 ± 1.77 years (range 4-8.8 years) after GKRS. At the final assessment, 6 of 12 patients were classified as seizure free (Engel Class Ia, n = 3; Ic, n = 2; and Id, n = 1) and 6 patients were classified as not seizure free (Engel Class II, n = 1; III, n = 2; and IV, n = 3). Neither initial nor late MRI signal changes after GKRS statistically correlated with surgical outcome. Clinical seizure outcome did not differ significantly with initial or late MRI changes after GKRS.

CONCLUSIONS

GKRS can be considered an alternative option when the patients with MTLE-HS who had recurrent or residual seizures after ATL refuse a second operation.

Trigeminal neuralgia without neurovascular compression presents earlier than trigeminal neuralgia with neurovascular compression

OBJECT

Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). To characterize what may be distinct patient populations, the authors examined age at onset in patients with TN with and without NVC.

METHODS

A retrospective review of patients undergoing posterior fossa surgery for Type I TN at Oregon Health & Science University from 2009 to 2013 was undertaken. Charts were reviewed, and imaging and operative data were collected for patients with and without NVC. Mean, median, and the empirical cumulative distribution of onset age were determined. Statistical analysis was performed using Student t-test, Wilcoxon and Kolmogorov-Smirnoff tests, and Kaplan-Meier analysis. Multivariate analysis was performed using a Cox proportional hazards model.

RESULTS

The charts of 219 patients with TN were reviewed. There were 156 patients who underwent posterior fossa exploration and microvascular decompression or internal neurolysis: 129 patients with NVC and 27 without NVC. Mean age at symptoms onset for patients with and without NVC was 51.1 and 42.6 years, respectively. This difference (8.4 years) was significant (t-test: p = 0.007), with sufficient power to detect an effect size of 8.2 years. Median age between groups with and without NVC was 53.25 and 41.2 years, respectively (p = 0.003). Histogram analysis revealed a bimodal age at onset in patients without NVC, and cumulative distribution of age at onset revealed an earlier presentation of symptoms (p = 0.003) in patients without NVC. Chi-square analysis revealed a trend toward female predominance in patients without NVC, which was not significant (p = 0.08). Multivariate analysis revealed that age at onset was related to NVC but not sex, symptom side or distribution, or patient response to medical treatment.

CONCLUSIONS

NVC is neither sufficient nor necessary for the development of TN. Patients with TN without NVC may represent a distinct population of younger, predominantly female patients. Further research into the pathophysiology underlying this debilitating disease is needed.

Complications following cranioplasty: incidence and predictors in 348 cases

OBJECT

The factors that contribute to periprocedural complications following cranioplasty, including patient-specific and surgery-specific factors, need to be thoroughly assessed. The aim of this study was to evaluate risk factors that predispose patients to an increased risk of cranioplasty complications and death.

METHODS

The authors conducted a retrospective review of all patients at their institution who underwent cranioplasty following craniectomy for stroke, subarachnoid hemorrhage, epidural hematoma, subdural hematoma, and trauma between January 2000 and December 2011. The following predictors were tested: age, sex, race, diabetic status, hypertensive status, tobacco use, reason for craniectomy, urgency status of the craniectomy, graft material, and location of cranioplasty. The cranioplasty complications included reoperation for hematoma, hydrocephalus postcranioplasty, postcranioplasty seizures, and cranioplasty graft infection. A multivariate logistic regression analysis was performed. Confidence intervals were calculated as the 95% CI.

RESULTS

Three hundred forty-eight patients were included in the study. The overall complication rate was 31.32% (109 of 348). The mortality rate was 3.16%. Predictors of overall complications in multivariate analysis were hypertension (OR 1.92, CI 1.22-3.02), increasing age (OR 1.02, CI 1.00-1.04), and hemorrhagic stroke (OR 3.84, CI 1.93-7.63). Predictors of mortality in multivariate analysis were diabetes mellitus (OR 7.56, CI 1.56-36.58), seizures (OR 7.25, CI 1.238-42.79), bifrontal cranioplasty (OR 5.40, CI 1.20-24.27), and repeated surgery for hematoma evacuation (OR 13.00, CI 1.51-112.02). Multivariate analysis was also applied to identify the variables that affect the development of seizures, the need for reoperation for hematoma evacuation, the development of hydrocephalus, and the development of infections.

CONCLUSIONS

The authors' goal was to provide the neurosurgeon with predictors of morbidity and mortality that could be incorporated in the clinical decision-making algorithm. Control of a patient's risk factors and early recognition of complications may help practitioners avoid the exhaustive list of complications.

On-demand pulsatile intracerebral delivery of carisbamate with closed-loop direct neurostimulation therapy in an electrically induced self-sustained focal-onset epilepsy rat model

OBJECT

The authors evaluated the preclinical feasibility of acutely stabilizing an active bihemispheric limbic epileptic circuit using closed-loop direct neurostimulation therapy in tandem with "on-demand'" convection-enhanced intracerebral delivery of the antiepileptic drug (AED) carisbamate. A rat model of electrically induced self-sustained focal-onset epilepsy was employed.

METHODS

A 16-contact depth-recording microelectrode was implanted bilaterally in the dentate gyrus (DG) of the hippocampus of Fischer 344 rats. The right microelectrode array included an integrated microcatheter for drug delivery at the distal tip. Bihemispheric spontaneous self-sustained limbic status epilepticus (SSLSE) was induced in freely moving rats using a 90-minute stimulation paradigm delivered to the right medial perforant white matter pathway. Immediately following SSLSE induction, closed-loop right PP stimulation therapy concurrent with on-demand nanoboluses of the AED [(14)C]-carisbamate (n = 4), or on-demand [(14)C]-carisbamate alone (n = 4), was introduced for a mean of 10 hours. In addition, 2 reference groups received either closed-loop stimulation therapy alone (n = 4) or stimulation therapy with saline vehicle only (n = 4). All animals were sacrificed after completing the specified therapy regimen. In situ [(14)C]-autoradiography was used to determine AED distribution.

RESULTS

Closed-loop direct stimulation therapy delivered unilaterally in the right PP aborted ictal runs detected in either ipsi- or contralateral hippocampi. Freely moving rats receiving closed-loop direct stimulation therapy with ondemand intracerebral carisbamate delivery experienced a significant reduction in seizure frequency (p < 0.001) and minimized seizure frequency variability during the final 50% of the therapy/recording session compared with closed-loop stimulation therapy alone.

CONCLUSIONS

Unilateral closed-loop direct stimulation therapy delivered to afferent hippocampal white matter pathways concurrent with on-demand ipsilateral intracerebral delivery of nano-bolused carisbamate can rapidly decrease the frequency of electrographic seizures in an active bihemispheric epileptic network. Additionally, direct pulsatile delivery of carisbamate can stabilize seizure frequency variability compared with direct stimulation therapy alone.

Seizure and anticonvulsant outcomes following stereotactic radiosurgery for intracranial arteriovenous malformations

OBJECT

Epilepsy associated with arteriovenous malformations (AVMs) has an unclear course after stereotactic radiosurgery (SRS). Neither the risks of persistent seizures nor the requirement for postoperative antiepileptic drugs (AEDs) are well defined.

METHODS

The authors performed a retrospective review of all patients with AVMs who underwent SRS at the University of Virginia Health System from 1989 to 2012. Seizure status was categorized according to a modified Engel classification. The effects of demographic, AVM-related, and SRS treatment factors on seizure outcomes were evaluated with logistic regression analysis. Changes in AED status were evaluated using McNemar's test.

RESULTS

Of the AVM patients with pre- or post-SRS seizures, 73 with pre-SRS epilepsy had evaluable data for subsequent analysis. The median patient age was 37 years (range 5-69 years), and the median follow-up period was 65.6 months (range 12-221 months). Sixty-five patients (89%) achieved seizure remission (Engel Class IA or IB outcome). Patients presenting with simple partial or secondarily generalized seizures were more likely to achieve Engel Class I outcome (p = 0.045). Twenty-one (33%) of 63 patients tapered off of pre-SRS AEDs. The incidence of freedom from AED therapy increased significantly after SRS (p < 0.001, McNemar's test). Of the Engel Class IA patients who continued AED therapy, 54% had patent AVM nidi, whereas only 19% continued AED therapy with complete AVM obliteration (p = 0.05).

CONCLUSIONS

Stereotactic radiosurgery is an effective treatment for long-term AVM-related epilepsy. Seizure-free patients on continued AED therapy were more likely to have residual AVM nidi. Simple partial or secondarily generalized seizure type were associated with better seizure outcomes following SRS.

Long-term outcomes of resective epilepsy surgery after invasive presurgical evaluation in children with tuberous sclerosis complex and bilateral multiple lesions

OBJECT

Tuberous sclerosis complex (TSC) with medically refractory epilepsy is characterized by multifocal brain abnormalities, traditionally indicating poor surgical candidacy. This single-center, retrospective study appraised seizurerelated, neuropsychological, and other outcomes of resective surgery in TSC patients with medically refractory epilepsy, and analyzed predictors for these outcomes.

METHODS

Patients with multilesional TSC who underwent epilepsy surgery between 2007 and 2012 were identified from an electronic database. All patients underwent multimodality noninvasive and subsequent invasive evaluation. Seizure outcomes were classified using the International League Against Epilepsy (ILAE) scale. The primary outcome measure was complete seizure remission (ILAE Class 1). Secondary outcome measures included 50% responder rate, change in full-scale IQ, electroencephalography improvement, and reduction in antiepileptic drug (AED) burden.

RESULTS

A total of 37 patients with TSC underwent resective surgery during the study period. After a mean follow-up of 5.68 ± 3.67 years, 56.8% achieved complete seizure freedom (ILAE Class 1) and 86.5% had ILAE Class 4 outcomes or better. The full-scale IQ on follow-up was significantly higher in patients with ILAE Class 1 outcome (66.70 ± 12.36) compared with those with ILAE Class 2 or worse outcomes (56.00 ± 1.41, p = 0.025). In 62.5% of the patients with ILAE Class 2 or worse outcomes, the number of AEDs were found to be significantly reduced (p = 0.004).

CONCLUSIONS

This study substantiates the evidence for efficacy of resective epilepsy surgery in patients with bilateral multilesional TSC. More than half of the patients were completely seizure free. Additionally, a high proportion achieved clinically meaningful reduction in seizure burden and the number of AEDs.

Spontaneous out-of-body experience in a child with refractory right temporoparietal epilepsy

The authors describe the case of a spontaneous out-of-body experience (OBE) in a 15-year-old right-handed boy with intractable epilepsy in whom psychosis had been misdiagnosed. After successful resection of a right temporoparietal focal cortical dysplasia, the OBE and seizures resolved. The authors analyzed the underlying causes of the OBE and discussed the mechanism of the OBE caused by an epileptic lesion.