Effect of Race and Insurance Type on Access to, and Outcomes of, Epilepsy Surgery: A Literature Review.

BACKGROUND: Despite higher rates of seizure freedom, a large proportion of patients with medically refractory seizures who could benefit from epilepsy surgery do not receive surgical treatment. This literature review describes the association of race and insurance status with epilepsy surgery access and outcomes. METHODS: Searches in Scopus and PubMed databases related to disparities in epilepsy surgery were conducted. The inclusion criteria consisted of data that could be used to compare epilepsy surgery patient access and outcomes by insurance or race in the United States. Two independent reviewers determined article eligibility. RESULTS: Of the 289 studies reviewed, 26 were included. Most of the studies were retrospective cohort studies (23 of 26) and national admissions database studies (13 of 26). Of the 17 studies that evaluated epilepsy surgery patient demographics, 11 showed that Black patients were less likely to receive surgery than were White patients or had an increased time to surgery from seizure onset. Nine studies showed that patients with private insurance were more likely to undergo epilepsy surgery and have shorter time to surgery compared with patients with public insurance. No significant association was found between the seizure recurrence rate after surgery with insurance or race. CONCLUSIONS: Black patients and patients with public insurance are receiving epilepsy surgery at lower rates after a prolonged waiting period compared with other patients with medically refractory epilepsy. These results are consistent across the current reported literature. Future efforts should focus on additional characterization and potential causes of these disparities to develop successful interventions.

"July Effect" in Spinal Fusions: A Coarsened Exact-Matched Analysis.

BACKGROUND: Few neurosurgical studies examine the July Effect within elective spinal procedures, and none uses an exact-matched protocol to rigorously account for confounders. OBJECTIVE: To evaluate the July Effect in single-level spinal fusions, after coarsened exact matching of the patient cohort on key patient characteristics (including race and comorbid status) known to independently affect neurosurgical outcomes. METHODS: Two thousand three hundred thirty-eight adult patients who underwent single-level, posterior-only lumbar fusion at a single, multicenter university hospital system were retrospectively enrolled. Primary outcomes included readmissions, emergency department visits, reoperation, surgical complications, and mortality within 30 days of surgery. Logistic regression was used to analyze month as an ordinal variable. Subsequently, outcomes were compared between patients with surgery at the beginning vs end of the academic year (ie, July vs April-June), before and after coarsened exact matching on key characteristics. After exact matching, 99 exactly matched pairs of patients (total n = 198) were included for analysis. RESULTS: Among all patients, operative month was not associated with adverse postoperative events within 30 days of the index operation. Furthermore, patients with surgeries in July had no significant difference in adverse outcomes. Similarly, between exact-matched cohorts, patients in July were observed to have noninferior adverse postoperative events. CONCLUSION: There was no evidence suggestive of a July Effect after single-level, posterior approach spinal fusions in our cohort. These findings align with the previous literature to imply that teaching hospitals provide adequate patient care throughout the academic year, regardless of how long individual resident physician assistants have been in their particular role.

Stereoelectroencephalography before 2 years of age.

OBJECTIVE: Stereoelectroencephalography (SEEG) is a widely used technique for localizing seizure onset zones prior to resection. However, its use has traditionally been avoided in children under 2 years of age because of concerns regarding pin fixation in the immature skull, intraoperative and postoperative electrode bolt security, and stereotactic registration accuracy. In this retrospective study, the authors describe their experience using SEEG in patients younger than 2 years of age, with a focus on the procedure's safety, feasibility, and accuracy as well as surgical outcomes. METHODS: A retrospective review of children under 2 years of age who had undergone SEEG while at Children's Hospital of Philadelphia between November 2017 and July 2021 was performed. Data on clinical characteristics, surgical procedure, imaging results, electrode accuracy measurements, and postoperative outcomes were examined. RESULTS: Five patients younger than 2 years of age underwent SEEG during the study period (median age 20 months, range 17-23 months). The mean age at seizure onset was 9 months. Developmental delay was present in all patients, and epilepsy-associated genetic diagnoses included tuberous sclerosis (n = 1), KAT6B (n = 1), and NPRL3 (n = 1). Cortical lesions included tubers from tuberous sclerosis (n = 1), mesial temporal sclerosis (n = 1), and cortical dysplasia (n = 3). The mean number of placed electrodes was 11 (range 6-20 electrodes). Bilateral electrodes were placed in 1 patient. Seizure onset zones were identified in all cases. There were no SEEG-related complications, including skull fracture, electrode misplacement, hemorrhage, infection, cerebrospinal fluid leakage, electrode pullout, neurological deficit, or death. The mean target point error for all electrodes was 1.0 mm. All patients proceeded to resective surgery, with a mean follow-up of 21 months (range 8-53 months). All patients attained a favorable epilepsy outcome, including Engel class IA (n = 2), IC (n = 1), ID (n = 1), and IIA (n = 1). CONCLUSIONS: SEEG can be safely, accurately, and effectively utilized in children under age 2 with good postoperative outcomes using standard SEEG equipment. With minimal modification, this procedure is feasible in those with immature skulls and guides the epilepsy team's decision-making for early and optimal treatment of refractory epilepsy through effective localization of seizure onset zones.

Single-Surgeon in Vivo Experience with the Zeiss QEVO Microinspection Tool: An Analysis of Its Use for Extending the Reach of Operative Visualization.

The operating microscope is a foundational tool in modern neurosurgery. Operating microscopes serve increasingly as the lynchpin for highly sophisticated visualization platforms incorporating many complementary technologies. The Zeiss QEVO microinspection tool is a 45-degree viewing endoscopic instrument integrated into the Zeiss KINEVO 900 operating microscope (Carl Zeiss AG, Oberkochen, Germany). The QEVO tool enables surgeons to "look around the corners" of the surgical field to optimize visualization within tight operative corridors. In this article, we document our experience using the QEVO microinspection tool in a series of complex cranial neurosurgery procedures. This report focuses on the handling, visualization, and overall utility of the QEVO tool for achieving optimal visualization in deep cranial corridors.

Virtual Exploration of Safe Entry Zones in the Brainstem: Comprehensive Definition and Analysis of the Operative Approach.

BACKGROUND: A detailed and accurate understanding of the intrinsic brainstem anatomy and the interrelationship between its internal tracts and nuclei and external landmarks is of paramount importance for safe and effective brainstem surgery. Using anatomical models can be an important step in increasing such understanding. In the present study, we have shown the applicability of our developed virtual 3-dimensional (3D) model in depicting the safe entry zones (SEZs) to the brainstem. METHODS: Accurate 3D virtual models of brainstem elements were created using high-resolution magnetic resonance imaging and computed tomography to depict the brainstem SEZs. RESULTS: All the described SEZs to different parts of the brainstem were successfully depicted using our 3D virtual models. CONCLUSIONS: The virtual models provide an immersive experience of brainstem anatomy, allowing users to understand the intricacies of the microdissection that is necessary to appropriately work through the brainstem nuclei and tracts toward a particular target. The models provide an unparalleled learning environment to understand the SEZs into the brainstem that can be used for training and research.

Anterior Subcutaneous Transposition With Expanded Polytetrafluoroethylene (ASTEP) for Cubital Tunnel Syndrome: Technical Note.

BACKGROUND: Ulnar nerve entrapment neuropathy at the elbow is the most common upper-extremity entrapment neuropathy after carpal tunnel syndrome. Surgical treatment can be complicated by perineural scarring and fibrosis, which may lead to recurrent symptoms. Expanded polytetrafluoroethylene (ePTFE) is a synthetic polymer with antiadhesive properties. OBJECTIVE: To introduce the operative technique and outcomes of anterior subcutaneous transposition with ePTFE (ASTEP) in primary and recurrent cubital tunnel neuropathy. METHODS: We studied 14 adult patients (11 men, 3 women; mean age, 45 yr) with cubital tunnel neuropathy (10 primary, 4 revision) who underwent surgery with the ASTEP technique between January 2008 and May 2018. Pain, numbness in the fourth/fifth fingers, and weakness of the intrinsic hand muscles were the most common presenting symptoms. Surgical outcomes were assessed using the modified McGowan and Wilson-Krout criteria. RESULTS: The average (± standard deviation) preoperative symptom duration was 12.1 ± 5.2 mo (McGowan Grade 1, n = 5; Grade 2, n = 6; Grade 3, n = 3). No intraoperative or postoperative complications were observed with the ASTEP technique. Postoperative follow-up ranged from 9 mo to 7 yr (mean, 4.3 yr). All 14 patients experienced improvement in or complete resolution of their symptoms after this unique intervention. CONCLUSION: Our novel technique of anterior transposition of the ulnar nerve with ePTFE was safe and highly effective in treating primary and recurrent ulnar nerve entrapment neuropathy at the elbow and represents an alternative to the current techniques.

The Neurosurgical Atlas: advancing neurosurgical education in the digital age.

OBJECTIVE: The advent of the internet and the popularity of e-learning resources has promoted a shift in medical and surgical education today. The Neurosurgical Atlas has sought to capitalize on this shift by providing easily accessible video and online education to its users on an international scale. The rising popularity of social media has provided new avenues for expanding that global reach, and the Atlas has sought to do just that. In this study, the authors analyzed user demographics and web traffic patterns to quantify the international reach of the Atlas and examined the potential impact of social media platforms on the expansion of that reach. METHODS: Twitter, Facebook, and Instagram metrics were extracted using each respective service's analytics tool from the date of their creation through October 2019. Google Analytics was used to extract website traffic data from September 2018 to September 2019 and app data from January 2019 to October 2019. The metrics extracted included the number of platform users/followers, user demographic information, percentage of new versus returning visitors, and a number of platform-specific values. RESULTS: Since the authors' previous publication in 2017, annual website viewership has more than doubled to greater than 500,000 viewing sessions in the past year alone; international users accounted for more than 60% of the visits. The Atlas Twitter account, established in August 2012, has more than 12,000 followers, primarily hailing from the United States, the United Kingdom, Canada, and Saudi Arabia. The Atlas Facebook account, established in 2013, has just over 13,000 followers, primarily from India, Egypt, and Mexico. The Atlas Instagram account (established most recently, in December 2018) has more than 16,000 followers and the highest percentage (31%) of younger users (aged 18-24 years). The Atlas app was officially launched in May 2019, largely via promotion on the Atlas social media platforms, and has since recorded more than 60,000 viewing sessions, 80% of which were from users outside the United States. CONCLUSIONS: The Neurosurgical Atlas has attempted to leverage the many e-learning resources at its disposal to assist in spreading neurosurgical best practice on an international scale in a novel and comprehensive way. By incorporating multiple social media platforms into its repertoire, the Atlas is able to ensure awareness of and access to these resources regardless of the user's location or platform of preference. In so doing, the Atlas represents a novel way of advancing access to neurosurgical educational resources in the digital age.

Microsurgical Management of Ventral Intradural-Extramedullary Cervical Meningiomas: Technical Considerations and Outcomes.

OBJECTIVE: Cervical meningiomas are uncommon intradural-extramedullary tumors that have a tendency to be situated anterior to the spinal cord. The optimal surgical corridor to reach purely ventral cervical meningiomas has not been established. This article presents a series of patients with ventral cervical meningiomas treated via 1 of 2 microneurosurgical approaches: the anterior approach with corpectomy and fusion or the posterolateral approach. METHODS: Eight patients who underwent surgical resection of solitary, histopathologically confirmed, intradural-extramedullary cervical meningiomas of purely ventral location were retrospectively examined. Preoperative and postoperative Nurick scores quantified the degree of ambulatory function. Patients were followed for an average of 2.1 years after surgery. Postoperative imaging was performed to determine the extent of resection and to assess for tumor recurrence. RESULTS: Two patients with lower cervical meningiomas underwent resection via an anterior approach with single-level corpectomy and fusion. Six patients were treated via a posterolateral approach including ipsilateral hemilaminectomy and partial facetectomy without fusion. No intraoperative or postoperative complications were observed. Gross total resection was achieved in 8 of 8 patients, although 1 patient exhibited tumor recurrence. Improvement in ambulatory function was observed in all patients. CONCLUSIONS: Purely ventral cervical meningiomas are uncommon and pose unique technical challenges for neurosurgeons. We document favorable outcomes from 2 cases of lower cervical meningioma treated via an anterior approach and 6 cases of upper cervical tumors treated via a posterolateral approach. This series demonstrates operative considerations for effectively managing ventral cervical meningiomas.

Spatial distribution of interictal spikes fluctuates over time and localizes seizure onset.

The location of interictal spikes is used to aid surgical planning in patients with medically refractory epilepsy; however, their spatial and temporal dynamics are poorly understood. In this study, we analysed the spatial distribution of interictal spikes over time in 20 adult and paediatric patients (12 females, mean age = 34.5 years, range = 5-58) who underwent intracranial EEG evaluation for epilepsy surgery. Interictal spikes were detected in the 24 h surrounding each seizure and spikes were clustered based on spatial location. The temporal dynamics of spike spatial distribution were calculated for each patient and the effects of sleep and seizures on these dynamics were evaluated. Finally, spike location was assessed in relation to seizure onset location. We found that spike spatial distribution fluctuated significantly over time in 14/20 patients (with a significant aggregate effect across patients, Fisher's method: P < 0.001). A median of 12 sequential hours were required to capture 80% of the variability in spike spatial distribution. Sleep and postictal state affected the spike spatial distribution in 8/20 and 4/20 patients, respectively, with a significant aggregate effect (Fisher's method: P < 0.001 for each). There was no evidence of pre-ictal change in the spike spatial distribution for any patient or in aggregate (Fisher's method: P = 0.99). The electrode with the highest spike frequency and the electrode with the largest area of downstream spike propagation both localized the seizure onset zone better than predicted by chance (Wilcoxon signed-rank test: P = 0.005 and P = 0.002, respectively). In conclusion, spikes localize seizure onset. However, temporal fluctuations in spike spatial distribution, particularly in relation to sleep and post-ictal state, can confound localization. An adequate duration of intracranial recording-ideally at least 12 sequential hours-capturing both sleep and wakefulness should be obtained to sufficiently sample the interictal network.

Risk factors associated with early adverse outcomes following craniotomy for malignant glioma in older adults.

INTRODUCTION: Craniotomy for tumor resection improves survival in adults aged ≥65 years with malignant glioma. However, the decision to attempt resection must be weighed against the near-term risks of surgery. This study examined risk factors associated with unfavorable 30-day outcomes following craniotomy for malignant glioma resection in older adult patients. MATERIALS AND METHODS: The American College of Surgeons National Surgical Quality Improvement Program database from 2012 to 2016 was queried for patients aged 65-89 years undergoing craniotomy for primary, supratentorial, malignant, intra-axial tumor resection. 30-day outcomes included mortality, life-threatening complication, unplanned readmission, reoperation, and change in living disposition. Independent risk factors were identified through multiple logistic regression. RESULTS: In total, 1016 cases met eligibility criteria. Death occurred in 35 cases (3.4%). 58 patients (5.7%) suffered at least one life-threatening complication. Risk factors for morbidity and mortality included frontal lobe tumor, corticosteroid use, dependent functional status, and underweight body mass index (BMI). Among 816 patients admitted from home, 33.9% experienced a change in living disposition, which was associated with advanced age, female sex, frontal lobe tumor, underweight BMI, and diabetes mellitus (among others). Readmission (11.8%) was most frequently attributed to altered mental status, seizure, or venous thromboembolism. Reoperation was rare (4.5%). DISCUSSION: Death and life-threatening morbidity were rare early outcomes for older adult patients undergoing malignant glioma resection. However, one in three patients admitted from home experienced a change in living disposition. Factors related to baseline state of health, tumor location, and corticosteroid regimen should be considered when anticipating the immediate postoperative course.

Immersive Three-Dimensional Modeling and Virtual Reality for Enhanced Visualization of Operative Neurosurgical Anatomy.

Learning the endless intricacies of operative neurosurgical anatomy requires that surgeons complement their intraoperative experiences with a variety of educational resources. In the past 2 decades, rapid improvements in digital graphics and computing power have enabled a new generation of 3-dimensional (3D) virtual resources that overcome limitations of more traditional 2-dimensional materials. Today, dozens of immersive 3D visualization platforms exist for applications such as learning neuroanatomy, simulating operative techniques, and planning surgical interventions with patient-specific models. The purpose of this article is to identify current applications of 3D digital modeling and virtual reality in neurosurgery. In addition, we showcase a new series of freely available 3D virtual-reality models created to assist in learning complex cranial anatomy. We anticipate these models to have a wide range of educational, clinical, and research applications. Three-dimensional visualization is poised to modernize the ways we learn and teach neurosurgical anatomy outside of the operating room. Future generations of neurosurgeons are expected to benefit from these technologies from the earliest stages of training.

Innovations in the Art of Microneurosurgery for Reaching Deep-Seated Cerebral Lesions.

Deep-seated cerebral lesions have fascinated and frustrated countless surgical innovators since the dawn of the microneurosurgical era. To determine the optimal approach, the microneurosurgeon must take into account the characteristics and location of the pathological lesion as well as the operator's range of technical expertise. Increasingly, microneurosurgeons must select between multiple operative corridors that can provide access to the surgical target. Innovative trajectories have emerged for many indications that provide more flexible operative angles and superior exposure but result in longer working distances and more technically demanding maneuvers. In this article, we highlight 4 innovative surgical corridors and compare their strengths and weaknesses against those of more conventional approaches. Our goal is to use these examples to illustrate the following principles of microneurosurgical innovation: (1) discover more efficient and flexible exposures with superior working angles; (2) ensure maximal early protection of critical neurovascular structures; and (3) effectively handle target pathology with minimal disruption of normal tissues.

Stereoelectroencephalography in Pediatric Epilepsy Surgery.

Stereoelectroencephalography (SEEG) is an invasive technique used during the surgical management of medically refractory epilepsy. The utility of SEEG rests in its ability to survey the three-dimensional organization of the epileptogenic zone as well as nearby eloquent cortices. Once concentrated to specialized centers in Europe and Canada, the SEEG methodology has gained worldwide popularity due to its favorable morbidity profile, superior coverage of deep structures, and ability to perform multilobar explorations without the need for craniotomy. This rapid shift in practice represents both a challenge and an opportunity for pediatric neurosurgeons familiar with the subdural grid approach. The purpose of this review is to discuss the indications, technique, and safety of long-term SEEG monitoring in children. In addition to reviewing the conceptual and technical points of the diagnostic evaluation, attention will also be given to SEEG-based interventions (e.g., radiofrequency thermo-coagulation).

Reproducibility of interictal spike propagation in children with refractory epilepsy.

OBJECTIVE: Interictal spikes are a characteristic feature of invasive electroencephalography (EEG) recordings in children with refractory epilepsy. Spikes frequently co-occur across multiple brain regions with discernable latencies, suggesting that spikes can propagate through distributed neural networks. The purpose of this study was to examine the long-term reproducibility of spike propagation patterns over hours to days of interictal recording. METHODS: Twelve children (mean age 13.1 years) were retrospectively studied. A mean ± standard deviation (SD) of 47.2 ± 40.1 hours of interictal EEG recordings were examined per patient (range 17.5-166.5 hours). Interictal recordings were divided into 30-minute segments. Networks were extracted based on the frequency of spike coactivation between pairs of electrodes. For each 30-minute segment, electrodes were assigned a "Degree Preference (DP)" based on the tendency to appear upstream or downstream within propagation sequences. The consistency of DPs across segments ("DP-Stability") was quantified using the Spearman rank correlation. RESULTS: Regions exhibited highly stable preferences to appear upstream, intermediate, or downstream in spike propagation sequences. Across networks, the mean ± SD DP-Stability was 0.88 ± 0.07, indicating that propagation patterns observed in 30-minute segments were representative of the patterns observed in the full interictal window. At the group level, regions involved in seizure generation appeared more upstream in spike propagation sequences. SIGNIFICANCE: Interictal spike propagation is a highly reproducible output of epileptic networks. These findings shed new light on the spatiotemporal dynamics that may constrain the network mechanisms of refractory epilepsy.

Application of Indocyanine Green During Arteriovenous Malformation Surgery: Evidence, Techniques, and Practical Pearls.

Indocyanine green (ICG) is a fluorescent molecule that enables visualization of hemodynamic flow through blood vessels. The first description of its application to the resection of arteriovenous malformations (AVMs) did not occur until 2007. Since then, industry leaders have rapidly integrated this optical technology into the intraoperative microscope, and the use of ICG videoangiography (VA) has since become routine in AVM surgery among some academic centers. A number of case series have been published since the introduction of ICG VA to AVM neurosurgery. These early reports with small sample sizes were largely qualitative, assigning to the technology "usefulness" and "benefit" scores as perceived by the operators. This lack of objectivity prompted the development of FLOW 800 software, a proprietary technology of Carl Zeiss Meditec AG (Oberkochen, Germany) that can quantify relative fluorescence intensity under the microscope to generate color maps and intensity curves for ad hoc and post hoc analyses, respectively. However, subsequent case series have done little to quantify the effect of ICG VA on outcomes. The available literature predominately concludes that ICG VA, although intuitive to deploy and interpret, is limited by its dependence on direct illumination and visualization. The subcortical components of AVMs represent a natural challenge to ICG-based flow analysis, and the scope of ICG VA has therefore been limited to AVMs with a high proportion of superficial angioarchitecture. As a result, digital subtraction angiography has remained the gold standard for confirming AVM obliteration. In this review, we provide an overview of the existing literature on ICG VA in AVM resection surgery. In addition, we describe our own experiences with ICG VA and AVMs and offer the senior author's surgical pearls for optimizing the marriage of fluorescence flow technology and AVM resection surgery.

What do you know? ERP evidence for immediate use of common ground during online reference resolution.

Recent evidence on the time-course of conversational perspective taking is mixed. Some results suggest that listeners rapidly incorporate an interlocutor's knowledge during comprehension, while other findings suggest that listeners initially interpret language egocentrically. A key finding in support of the egocentric view comes from visual-world eye-tracking studies - listeners systematically look at potential referents that are known to them but unknown to the speaker. An alternative explanation is that eye movements might be driven by attentional processes that are unrelated to referent identification. To address this question, we assessed the time-course of perspective taking using event-related potentials (ERP). Participants were instructed to select a referent from a display of four animals (e.g., "Click on the brontosaurus with the boots") by a speaker who could only see three of the animals. A competitor (e.g., a brontosaurus with a purse) was either mutually visible, visible only to the listener, or absent from the display. Results showed that only the mutually visible competitor elicited an ERP signature of referential ambiguity. Critically, ERPs exhibited no evidence of referential confusion when the listener had privileged access to the competitor. Contra the egocentric hypothesis, this pattern of results indicates that listeners did not consider privileged competitors to be candidates for reference. These findings are consistent with theories of language processing that allow socio-pragmatic information to rapidly influence online language comprehension. The results also suggest that eye-tracking evidence in studies of online reference resolution may include distraction effects driven by privileged competitors and highlight the importance of using multiple measures to investigate perspective use.

Resting-state alpha power is selectively associated with autistic traits reflecting behavioral rigidity.

Previous research suggests that variation in at-rest neural activity correlates with specific domains of the ASD phenotype; however, few studies have linked patterns of brain activity with autistic trait expression in typically developing populations. The purpose of this study was to examine associations between resting-state electroencephalography (EEG) and three domains of the broader autism phenotype (social interest, rigidity, and pragmatic language) in typically developing individuals. High-density scalp EEG was recorded in thirty-seven typically developing adult participants (13 male, aged 18-52 years). The Broad Autism Phenotype Questionnaire (BAP-Q) was used to measure autistic trait expression. Absolute alpha power (8-13 Hz) was extracted from eyes-closed epochs using spectral decomposition techniques. Analyses revealed a specific positive association between scores on the BAP-Q Rigidity subscale and alpha power in the parietal scalp region. No significant associations were found between alpha power and the BAP-Q Aloofness or Pragmatic Language subscales. Furthermore, the association between EEG power and behavioral rigidity was specific to the alpha frequency band. This study demonstrates that specific traits within the broader autism phenotype are associated with dissociable patterns of at-rest neural activity.