Inactivation of Hedgehog signal transduction in adult astrocytes results in region-specific blood-brain barrier defects.

In this study, we use molecular genetic approaches to clarify the role of the Hedgehog (Hh) pathway in regulating the blood-brain/spinal cord barrier (BBB) in the adult mouse central nervous system (CNS). Our work confirms and extends prior studies to demonstrate that astrocytes are the predominant cell type in the adult CNS that transduce Hh signaling, revealed by the expression of Gli1, a target gene of the canonical pathway that is activated in cells receiving Hh, and other key pathway transduction components. Gli1+ (Hh-responsive) astrocytes are distributed in specific regions of the CNS parenchyma, including layers 4/5/6 of the neocortex, hypothalamus, thalamus, and spinal cord, among others. Notably, although BBB properties in endothelial cells are normally regulated by both paracellular and transcellular mechanisms, conditional inactivation of Hh signaling in astrocytes results in transient, region-specific BBB defects that affect transcytosis but not paracellular diffusion. These findings stand in contrast to prior studies that implicated astrocytes as a source of Sonic hedgehog that limited extravasation via both mechanisms [J. I. Alvarez et al., Science 334, 1727-1731 (2011)]. Furthermore, using three distinct Cre driver lines as well as pharmacological approaches to inactivate Hh-pathway transduction globally in CNS astrocytes, we find that these specific BBB defects are only detected in the rostral hypothalamus and spinal cord but not the cortex or other regions where Gli1+ astrocytes are found. Together, our data show that Gli1+ Hh-responsive astrocytes have regionally distinct molecular and functional properties and that the pathway is required to maintain BBB properties in specific regions of the adult mammalian CNS.

The deep roots of military service in neurological surgery: an academic genealogical analysis of the founding generation.

Throughout human history, advancements in medicine have evolved out of periods of war. The carnage of battlefield injuries provided wartime surgeons an unprecedented opportunity to study anatomy, develop novel techniques, and improve systems of care. As a specialty that was established and evolved during the first half of the 20th century, neurological surgery was heavily influenced by the experiences of its founders during the World Wars I and II. Utilizing the published Neurosurgery Tree, the authors conducted an academic genealogical analysis to systematically define the influence of wartime service on neurosurgery's earliest generations. Through review of the literature and military records, the authors determined that at least 60% of American neurosurgical founders and early leaders served during World Wars I and/or II. Inspired by the call to serve their nation as forces for good, these individuals were heralded as expert clinicians, innovative systems thinkers, and prolific researchers. Importantly, the service of these early leaders helped highlight the viability of neurosurgery as a distinct specialty and provided a framework for early neurosurgical education and expansion. The equipment, techniques, and guidelines that were developed during these wars, such as management of craniocerebral trauma, peripheral nerve repair, and hemostasis, set the foundation for modern neurosurgical practice.

Characteristics and outcomes of stroke hospitalizations in patients with sickle cell disease and moyamoya syndrome.

OBJECTIVES: Stroke is the leading cause of death in patients with Sickle cell disease (SCD). Here, we detail the burden of Moyamoya syndrome (MMS) as a cause of stroke in patients with SCD. MATERIALS AND METHODS: A review of SCD-related hospital discharges was conducted utilizing the National Inpatient Sample. Rates of stroke hospitalization, risk factors, procedures, and outcomes were compared between patients with SCD-MMS and SCD alone. Univariate analyses including T-test, Wilcoxon Rank-Sum test, Chi-square were performed to compare risk factors and outcomes. Multivariable regression was used to identify predictors of stroke unique to each population. RESULTS: Stroke occurred in 9.8% of SCD-MMS hospitalizations versus 0.5% of those involving patients with SCD alone (OR = 20.71, p < 0.001). Patients with SCD-MMS developed stroke at younger ages and with fewer comorbidities compared to those with SCD alone. Stroke hospitalizations in SCD-MMS involved a greater number of procedures (90.5% vs. 79.3%, p = 0.007), but were more likely to result in favorable discharge (58.5% vs. 44.2%, p = 0.005). The presence of anemia during hospitalization was a significant risk factor for stroke in both cohorts. Long-term antiplatelet use was protective against stroke (OR = 0.42, p = 0.008) only in the SCD-MMS cohort. CONCLUSIONS: MMS confers a 20-fold increased risk of stroke among patients with SCD and appears to be an important cause of recurrent stroke in this population. Anemia is one of the most significant risk factors for stroke, while antiplatelet use appears to confer a protective benefit.

Outcomes of Mechanical Thrombectomy for Ischemic Stroke in Nonagenarians: A 10-Year Institutional Experience.

BACKGROUND: Nonagenarians have been underrepresented in stroke trials that established endovascular treatment as the standard for acute ischemic stroke (AIS). Evidence remains inconclusive regarding the efficacy of thrombectomy in this population. OBJECTIVES: To report our experience with thrombectomy in nonagenarians with stroke, and to identify predictors of mortality. We further investigated the effects of first-pass reperfusion and the addition of intravenous thrombolysis (IVT) on achieving better outcomes. MATERIALS AND METHODS: Data was collected for consecutively treated patients at three affiliated comprehensive stroke centers from 2010 to 2021. We included patients ≥90 years-old with AIS secondary to large vessel occlusion. Bivariate analyses were performed using the Mann-Whitney U test for continuous variables, and χ2 and Fisher's exact tests, respectively, for nominal and ordinal variables. RESULTS: Thirty-two nonagenarians underwent thrombectomy, of whom 25 (81%) had prestroke mRS ≤2. Thrombectomies were performed using stents (2, 6.7%), aspiration (8, 26.7%), or a combination of both (20, 66.7%). Successful recanalization was achieved in 97%. Procedural complications occurred in 2 (6.3%) and intracranial hemorrhage in 3 (9.4%). Sixteen patients (50%) were discharged home or to rehabilitation, 9 (28.2%) to nursing home or hospice, and 7 (21.9%) died during hospitalization. Only 2 (6%) patients had mRS ≤2 at discharge. No independent predictors of in-hospital mortality were identified, and neither first-pass reperfusion nor the addition of IVT correlated with improvement in clinical outcome. CONCLUSIONS: Although thrombectomy is safe for nonagenarian stroke and can achieve excellent recanalization, high mortality and poor functional status remain high given the advanced age and frailty of this population.

Compliance With Preferred Reporting Items for Systematic Review and Meta-Analysis Individual Participant Data Statement for Meta-Analyses Published for Stroke Studies.

Background and Purpose: Individual-participant data meta-analyses (IPD-MA) are powerful evidence synthesis studies which are considered the gold-standard of MA. The quality of reporting in these studies is guided by the 2015 Preferred Reporting Items for Systematic Review and Meta-Analysis of Individual Participant Data (PRISMA-IPD) guidelines. The growing number of IPD-MA published for stroke studies calls for an assessment of the compliance of these studies with the PRISMA-IPD statement. Methods: PubMed and EMBASE were searched for MA in stroke published between January 1, 2016, and March 30, 2020, in journals with impact factor >2. Literature reviews, scoping reviews, and aggregate MA were excluded. The final articles were scored using the 31-item PRISMA-IPD checklist. Results were depicted using descriptive statistics. Compliance with each item in PRISM-IPD guideline was recorded. The study was defined as compliant to IPD analyses if it satisfied all IPD specific items. Results: From an initial set of 321 articles, 31 met the final eligibility for data extraction. Only 4 (13%) described the use of PRISMA-IPD guidelines in their methodology, while 8/31 (26%) used the old PRISMA guidelines and 19/31 (61%) followed none. Regardless of mention of using IPD specific guidelines, 42% (n=13) of studies were compliant with all 4 IPD specific domains. The poorest areas of compliance were bias assessment within (32%) and across (39%) studies, reporting protocol and registration (42%), and reporting of IPD integrity (48%). The median journal impact factor was similar between the compliant (median, 8.1 [interquartile range, 5.4­39.9]) and noncompliant (median, 6 [interquartile range, 4.5­16.2]) groups (P=0.24). Similarly, the journal, country of correspondence, number of authors, number of studies included in MA, study sample size, and funding source were statistically similar between the groups. Conclusions: For the published IPD-MA stroke studies, the compliance with PRISMA-IPD statement and compliance with 4 IPD specific items was suboptimal. The journal, author, and study-related factors were not associated with compliance. Additional scrutiny measures to ensure adherence to mandated guidelines might increase the compliance. Several avenues to improve compliance and ensure optimal adherence are discussed.

Experimental animal models for moyamoya disease and treatment: a pathogenesis-oriented scoping review.

OBJECTIVE: Moyamoya disease (MMD) is an intracranial steno-occlusive pathology characterized by progressive narrowing of proximal large vessels, including the terminal internal carotid arteries (ICAs), middle cerebral arteries, or anterior cerebral arteries. Named for the "puff of smoke" appearance of the anomalous vascularization visualized on cerebral angiography, MMD lacks a well-defined etiology, although significant insights have been made, including the identification of a susceptibility gene, RNF213, in humans with the disease. A limitation to advancing the understanding and treatment of MMD has been the lack of experimental animal models that authentically reflect the clinical pathogenesis. In an effort to analyze characteristics of currently available models and identify strategies for future model generation, the authors performed a scoping review of experimental animal models that have been used to study MMD. METHODS: A systematic search of PubMed, Web of Science, and Scopus was performed to identify articles describing animal models used to study MMD. Additional articles were identified via citation searching. Study selection and data extraction were performed by two independent reviewers based on defined inclusion and exclusion criteria. RESULTS: A total of 44 articles were included for full-text review. The methods used to generate these animal models were broadly classified as surgical (n = 25, 56.8%), immunological (n = 7, 15.9%), genetic (n = 6, 13.6%), or a combination (n = 6, 13.6%). Surgical models typically involved permanent ligation of one or both of the common carotid arteries or ICAs to produce chronic cerebral hypoperfusion. Genetic models utilized known MMD or cerebrovascular disease-related genes, such as RNF213 or ACTA2, to induce heritable cerebral vasculopathy. Finally, immunological models attempted to induce vasculitis-type pathology by recapitulating the inflammatory milieu thought to underlie MMD. CONCLUSIONS: Models generated for MMD have involved three general approaches: surgical, immunological, and genetic. Although each reflects a key aspect of MMD pathogenesis, the failure of any individual model to recapitulate the development, progression, and consequences of the disease underscores the importance of future work in developing a multietiology model.

Knobloch Syndrome, a Rare Cause of Occipital Encephalocele and Seizures: A Case Report.

BACKGROUND: Knobloch syndrome (KS) is a rare autosomal recessive disorder associated with multiple ocular and cranial abnormalities. Occult occipital skull defect or encephalocele should raise suspicion of this disease. It is never reported in neurosurgical literature, possibly due to a lack of clinician familiarity, leading to underdiagnosis and inadequate management. Our patient also had seizures, which is a sporadic presentation of this syndrome. CASE DESCRIPTION: Here, we report a clinico-radiologic finding of a 7-year-old boy who presented with seizures, cataracts, and an occipital bone defect along with bilateral subependymal heterotopias and polymicrogyria. CONCLUSIONS: This case highlights the importance of consideration of this syndrome in children with a midline occipital bone defect with or without encephalocele and seizures. Early recognition of this presentation is critical for obtaining access to appropriate genetic counseling and subsequent monitoring and prevention of complications by surgical intervention.

Management of Jugular Bulb Stenosis in Pediatric Vein of Galen Malformation: A Novel Management Paradigm.

INTRODUCTION: Pediatric vein of Galen malformations (VOGMs) are fistulous intracranial malformations arising congenitally within the choroidal fissure that can present with an array of neurological and cardiac sequelae. Associated venous stenosis may result in intracranial venous hypertension and ischemia leading to severe, irreversible cerebral injury. Management of neonatal VOGMs typically involves staged embolization and angioplasty/stenting for relief of venous stenosis. Rarely, jugular foraminal narrowing has been identified as causing jugular bulb stenosis. CASE PRESENTATION: We present the case of a 22-month-old female diagnosed with VOGM prenatally who displayed persistent intracranial venous hypertension despite multiple neuroembolization procedures during the neonatal period. Following initial reduction in arteriovenous shunting, she once again developed venous hypertension secondary to jugular bulb stenosis for which angioplasty was attempted. Failure of angioplasty to relieve the venous hypertension prompted skull base imaging, which revealed jugular foraminal ossification and stenosis. Microsurgical jugular foraminotomy followed by balloon angioplasty and stenting significantly reduced jugular pressure gradients. Restenosis requiring re-stenting developed postoperatively at 9 months, but the patient has remained stable with significant improvement in cortical venous congestion. DISCUSSION/CONCLUSION: This case demonstrates the efficacy of microsurgical decompression of the jugular foramen and endovascular angioplasty/stenting as a novel treatment paradigm for the management of intracranial venous hypertension in the setting of VOGM.

An analysis of cross-continental scholarship requirements during neurosurgical training and national research productivity.

OBJECTIVE: Engagement in research and scholarship is considered a hallmark of neurosurgical training. However, the participation of neurosurgical trainees in this experience has only recently been analyzed and described in the United States, with little, if any, data available regarding the research environment in neurosurgical training programs across the globe. Here, the authors set out to identify requirements for research involvement and to quantify publication rates in leading neurosurgical journals throughout various nations across the globe. METHODS: The first aim was to identify the research requirements set by relevant program-accrediting and/or board-certifying agencies via query of the literature and published guidelines. For the second part of the study, the authors attempted to determine each country's neurosurgical research productivity by quantifying publications in the various large international neurosurgical journals-World Neurosurgery, Journal of Neurosurgery, and Neurosurgery-via a structured search of PubMed. RESULTS: Data on neurosurgical training requirements addressing research were available for 54 (28.1%) of 192 countries. Specific research requirements were identified for 39 countries, partial requirements for 8, and no requirements for 7. Surprisingly, the authors observed a trend of increased average research productivity with the absence of designated research requirements, although this finding is not unprecedented in the literature. CONCLUSIONS: A variety of countries of various sizes and neurosurgical workforce densities across the globe have instituted research requirements during training and/or prior to board certification in neurosurgery. These requirements range in intensity from 1 publication or presentation to the completion of a thesis or dissertation and occur at various time points throughout training. While these requirements do not correlate directly to national research productivity, they may provide a foundation for developing countries to establish a culture of excellence in research.

Atrophin protein RERE positively regulates Notch targets in the developing vertebrate spinal cord.

The Notch signaling pathway controls cell fate decision, proliferation, and other biological functions in both vertebrates and invertebrates. Precise regulation of the canonical Notch pathway ensures robustness of the signal throughout development and adult tissue homeostasis. Aberrant Notch signaling results in profound developmental defects and is linked to many human diseases. In this study, we identified the Atrophin family protein RERE (also called Atro2) as a positive regulator of Notch target Hes genes in the developing vertebrate spinal cord. Prior studies have shown that during early embryogenesis in mouse and zebrafish, deficit of RERE causes various patterning defects in multiple organs including the neural tube. Here, we detected the expression of RERE in the developing chick spinal cord, and found that normal RERE activity is needed for proper neural progenitor proliferation and neuronal differentiation possibly by affecting Notch-mediated Hes expression. In mammalian cells, RERE co-immunoprecipitates with CBF1 and Notch intracellular domain (NICD), and is recruited to nuclear foci formed by over-expressed NICD1. RERE is also necessary for NICD to activate the expression of Notch target genes. Our findings suggest that RERE stimulates Notch target gene expression by preventing degradation of NICD protein, thereby facilitating the assembly of a transcriptional activating complex containing NICD, CBF1/RBPjκ in vertebrate, Su(H) in Drosophila melanogaster, Lag1 in C. elegans, and other coactivators.

Gender Differences in Medicare Practice and Payments to Neurosurgeons.

Importance: Despite efforts to promote diversity within the neurosurgical workforce, individuals from underrepresented groups face significant challenges. Objective: To compare practice metrics and earning potential between female and male neurosurgeons and investigate factors associated with gender disparity in Medicare reimbursement. Design, Setting, and Participants: This retrospective cross-sectional study used publicly accessible Medicare data on reimbursements to female and male neurosurgeons for procedural and evaluation and management services delivered in both inpatient and outpatient settings between January 1, 2013, and December 31, 2020. Data were analyzed from December 9, 2021, to December 5, 2022. Main Outcomes and Measures: The primary outcome was the mean annual payments received and charges submitted by female and male neurosurgeons for services rendered between 2013 and 2020. Secondary outcomes included the total number and types of services rendered each year and the number of beneficiaries treated. Univariate and multivariable analyses quantified differences in payment, practice volume, and composition. Results: A total of 6052 neurosurgeons (5540 men [91.54%]; 512 women [8.46%]) served the Medicare fee-for-service patient population. Female neurosurgeons billed for lesser Medicare charges (mean [SE], $395 851.62 [$19 449.39] vs $766 006.80 [$11 751.66]; P < .001) and were reimbursed substantially less (mean [SE], $69 520.89 [$2701.30] vs $124 324.64 [$1467.93]; P < .001). Multivariable regression controlling for practice volume metrics revealed a persistent reimbursement gap (-$24 885.29 [95% CI, -$27 964.72 to -$21 805.85]; P < .001). Females were reimbursed $24.61 less per service than males even after matching services by code (P = .02). Conclusions and Relevance: This study found significant gender-based variation in practice patterns and reimbursement among neurosurgeons serving the Medicare fee-for-service population. Female surgeons were reimbursed less than male surgeons when both performed the same primary procedure. Lower mean reimbursement per service may represent divergence in billing and coding practices among females and males that could be the focus of future research or educational initiatives.

State-to-State Variation in Medicaid Reimbursement for Neurosurgical Procedures: Implications for Healthcare Access in Vulnerable Populations.

BACKGROUND AND OBJECTIVES: Medicaid payment for healthcare services traditionally reimburses less than Medicare and commercial insurance. This disparity in reimbursement seems to be an important driver of limited access to care among Medicaid beneficiaries. This study seeks to examine the degree of variation in Medicaid and Medicare reimbursement for the most common neurosurgical current procedural terminology codes and determine its potential impact on provider accessibility. METHODS: In this cross-sectional study, maximum allowed physician reimbursement fees for 20 common neurosurgical codes reported in the literature were obtained from the 2022 Medicare Physician Fee Schedule and individual state Medicaid Fee-for-Service Schedules. The Medicaid-Medicare Index (MMI), which measures Medicaid reimbursement as a fraction of Medicare allowed amounts, was calculated for each procedure across 49 states and the District of Columbia. Lower MMI indicates a greater disparity, or "discount," between Medicaid and Medicare reimbursement. The proportion of providers accepting new Medicaid patients and total Medicaid enrollment were compared across states as a function of MMI. RESULTS: The average national MMI was 0.79, with a range of 0.37 in NY/NJ to 1.43 in NE. Maximum allowed amounts for Medicare reimbursement (coefficient of variation = 0.09) were less variable than those for Medicaid (coefficient of variation = 0.26, P < .01). The largest absolute disparity was observed for intracranial aneurysm clipping in NY, where the maximum Medicaid reimbursement is $3496.52 less than that of Medicare. Higher MMI was associated with a significantly larger proportion of providers accepting new Medicaid patients (R2 = 0.43, P < .01). Moreover, MMI varied inversely with the number of Medicaid beneficiaries (R2 = 0.12, P = .01). CONCLUSION: Medicaid reimbursement varies between states reflecting the disparate methods of fee schedule calculation. Lower reimbursement is associated with more limited provider enrollment, especially in states with a greater number of beneficiaries.

The western giants of neuroanatomical past: an ode to yesterday - Part I.

"The only history is a mere question of one's struggle inside oneself. But that is the joy of it. One need neither discover Americas nor conquer nations, and yet one has as great a work as Columbus or Alexander to do," said David H. Lawrence. In this historical vignette, we look at the lives of certain western giants of neuroanatomy from the past. To understand the origin of today's advancements and successes in neurosurgery, a strong foothold on the path taken by anatomical greats is necessary. What curiosity inspired them to search the meaning of the human nervous system? Learning this from the paths of Herophilus, Galen, Franciscus Sylvius, Thomas Willis, Alexander Monro secundus, Luigi Rolando, François Magendie, and Martin Rathke, will propel us to create a better future for our successors.

The Western giants of the neuroanatomical past: an ode to yesterday. Part II.

"The history of the world is the biography of the great man. And I said: the great man always acts like a thunder. He storms the skies, while others are waiting to be stormed," said Thomas Carlyle. In this historical vignette, we study the contribution to neuroanatomy, of greats from the past. What led them to find the basis of topography and anatomical localization? How did they unravel the pathways of cerebrospinal fluid and cortical structure of the human brain? To understand this, we study the paths of Pierre Paul Broca, Richard L. Heschl, Hubert von Luschka, Carl Wernicke, Hans Chiari, Ludwig Edinger, and Carl Westphal, Korbinian Brodmann, and Walter Dandy.

Evaluating academic productivity and match outcomes in neurosurgery residents from medical schools without a neurosurgery residency program: a 2016-2022 bibliometric analysis.

OBJECTIVE: Transition of the United States Medical Licensing Examination Step 1 to a pass/fail structure has focused attention on medical student research in residency application. Previous studies have explored how various factors affect the neurosurgery match success, but none have focused on applicants from schools without a neurosurgery residency program. METHODS: The authors compiled a list of neurosurgery residents matched from 2016 to 2022 from schools lacking a neurosurgery program. They gathered demographic and bibliometric data, focusing on academic productivity before residency. The distinction between the top 40 and non-top 40 programs used the 5-year institutional h-index (ih[5]-index) of departments. RESULTS: Between 2016 and 2022, the gross number of students entering neurosurgery from schools without a home program rose from 15 to 26 in 2021, declining to 23 in 2022. The range of matched applicants per school was 0 to 10. The median number of publications per resident increased from 2 in 2016 to 5 in 2022 (p < 0.001). The lowest and highest numbers of publications by applicants were 0 and 40, respectively, with 22.5% reporting no publications. The lowest and highest h-indices by applicants were 0 and 11, respectively, with nearly one-third (31.2%) possessing an h-index of 0. Applicants from schools lacking a neurosurgery residency program who matched into top 40 programs had a publication range of 0-11, with a higher median of 3 compared with those who did not (median 2, range 0-8). While no significant differences were found in publication numbers (p = 0.084), a difference in h-index was observed (p = 0.024) between the two groups. Publications significantly correlated with the h-index, with each additional publication increasing the h-index by 0.19 (p < 0.001, adjusted R2 = 0.3348). CONCLUSIONS: Median publication counts have increased in this cohort, but they do not distinguish top 40 program matches. Conversely, the h-index, correlating with publication quantity and journal impact factor, does.

The impact of post-operative enteral nutrition on duodenal injury outcomes: A post hoc analysis of an EAST multicenter trial.

BACKGROUND: Leak following surgical repair of traumatic duodenal injuries results in prolonged hospitalization and oftentimes nil per os(NPO) treatment. Parenteral nutrition(PN) has known morbidity; however, duodenal leak(DL) patients often have complex injuries and hospital courses resulting in barriers to enteral nutrition(EN). We hypothesized EN alone would be associated with 1)shorter duration until leak closure and 2)less infectious complications and shorter hospital length of stay(HLOS) compared to PN. METHODS: This was a post-hoc analysis of a retrospective, multicenter study from 35 Level-1 trauma centers, including patients >14 years-old who underwent surgery for duodenal injuries(1/2010-12/2020) and endured post-operative DL. The study compared nutrition strategies: EN vs PN vs EN + PN using Chi-Square and Kruskal-Wallis tests; if significance was found pairwise comparison or Dunn's test were performed. RESULTS: There were 113 patients with DL: 43 EN, 22 PN, and 48 EN + PN. Patients were young(median age 28 years-old) males(83.2%) with penetrating injuries(81.4%). There was no difference in injury severity or critical illness among the groups, however there were more pancreatic injuries among PN groups. EN patients had less days NPO compared to both PN groups(12 days[IQR23] vs 40[54] vs 33[32],p = <0.001). Time until leak closure was less in EN patients when comparing the three groups(7 days[IQR14.5] vs 15[20.5] vs 25.5[55.8],p = 0.008). EN patients had less intra-abdominal abscesses, bacteremia, and days with drains than the PN groups(all p < 0.05). HLOS was shorter among EN patients vs both PN groups(27 days[24] vs 44[62] vs 45[31],p = 0.001). When controlling for predictors of leak, regression analysis demonstrated EN was associated with shorter HLOS(ß -24.9, 95%CI -39.0 to -10.7,p < 0.001). CONCLUSION: EN was associated with a shorter duration until leak closure, less infectious complications, and shorter length of stay. Contrary to some conventional thought, PN was not associated with decreased time until leak closure. We therefore suggest EN should be the preferred choice of nutrition in patients with duodenal leaks whenever feasible. LEVEL OF EVIDENCE: IV.

Targeted Public Health Training for Neurosurgeons: An Essential Task for the Prioritization of Neurosurgery in the Evolving Global Health Landscape.

The gap between the tremendous burden of neurological disease requiring surgical management and the limited capacity for neurosurgical care has fueled the growth of the global neurosurgical movement. It is estimated that an additional 23 300 neurosurgeons are needed to meet the burden posed by essential cases across the globe. Initiatives to increase neurosurgical capacity through systems strengthening and workforce development are key elements in correcting this deficit. Building on the growing interest in global health among neurosurgical trainees, we propose the integration of targeted public health education into neurosurgical training, in both high-income countries and low- and middle-income countries. This effort will ensure that graduates possess the fundamental skillsets and experience necessary to participate in and lead capacity-building efforts in the developing countries. This additional public health training can also help neurosurgical residents to achieve the core competencies outlined by accreditation boards, such as the Accreditation Committee on Graduate Medical Education in the United States. In this narrative review, we describe the global burden of neurosurgical disease, establish the need and role for the global neurosurgeon, and discuss pathways for implementing targeted global public health education in the field of neurosurgery.

Tension Pneumocranium Following Transsphenoidal Surgeries-A Case Report and Systematic Review of Literature with Analysis of Predisposing Factors and Treatment Regimens: Is Early Skull Base Repair Better than Conservative Treatment?

BACKGROUND: Conclusive evidence describing the outcomes following different treatment strategies for tension pneumocranium (TP) is lacking. Impact of predisposing conditions like multiple transnasal transsphenoidal (TNTS) procedures, intraoperative cerebrospinal fluid leak, obstructive sleep apnea, continuous positive airway pressure, violent coughing, nose blowing, positive pressure ventilation on TP outcomes is also unknown. METHODS: PubMed, Embase, Cochrane, and Google Scholar were searched for articles using Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Multivariate logistic regression analysis was done using STATA/ BE ver 17.0. RESULTS: Thirty-five studies with 49 cases of endoscopic TNTS surgeries were included. Tension pneumocephalus was seen in 77.5% (n = 38), tension pneumosella in 7 (14.28%), and tension pneumoventricle in 4 (8.16%). Nonfunctional pituitary adenomas (40.81%) were most common lesions associated with TP. The need of mechanical ventilation was significantly higher in patients who received conservative management (odds ratio, 1.34; confidence interval, 0.65-2.74) (P < 0.01). However, incidence of meningitis or mortality were not influenced by factors like age, gender, pathological diagnosis, initial conservative management or early skull base repair, use of adjuvant radiation, intraoperative cerebrospinal fluid leak, multiple TNTS explorations, or presence of precipitating factors. CONCLUSIONS: Nonfunctional pituitary adenomas were the most common lesions associated with TP. Multiple TNTS procedures did not increase incidence of meningitis or mortality. Conservative management increased the need for mechanical ventilation but did not worsen the mortality outcomes.

Aortic arch anomalies, embryology and their relevance in neuro-interventional surgery and stroke: A review.

BACKGROUND: Congenital aortic arch anomalies are commonly encountered during neurointerventional procedures. While some anomalies are identified at an early age, many are incidentally discovered later in adulthood during endovascular evaluations or interventions. Proper understanding of the normal arch anatomy and its variants is pivotal to safely navigate normal aortic arch branches and to negotiate the catheter through anomalies during neurointerventional procedures. This is particularly relevant in the increasingly "transradial first" culture of neurointerventional surgery. Moreover, some of these anomalies have a peculiar predilection for complications including aneurysm formation, dissection, and rupture during the procedure. Therefore, an understanding of these anomalies, their underlying embryological basis and associations, and pattern of circulation will help endovascular neurosurgeons and interventional radiologists navigate with confidence and consider relevant pathologic associations that may inform risk of cerebrovascular disease. METHODS: Here, we present a brief review of the basic embryology of the common anomalies of the aortic arch along with their neurological significances and discuss, through illustrative cases, the association of aortic arch anomalies with cerebral vascular pathology. CONCLUSIONS: Understanding the aortic arch anomalies and its embryological basis is essential to safely navigate the cerebral vascular system during neurointerventional surgeries.

Multi-modal endovascular management of traumatic pseudoaneurysm and arteriovenous fistula of the ascending cervical artery: A technical report and review of literature.

OBJECTIVE: The management of traumatic pseudoaneurysm (PA) with concomitant arteriovenous fistula (AVF) arising from the thyrocervical trunk is challenging and rarely reported. Here, the usefulness of a multi-modal endovascular strategy for management of traumatic PA and AVF arising from the thyrocervical trunk is presented. A literature review describing unique clinical features and management strategies of traumatic vascular lesions of the thyrocervical trunk is included. METHODS: A 58-year-old man presented with two PAs arising from the ascending cervical artery (AsCA) and a robust AVF between the AsCA and the left vertebral venous plexus which arose acutely after a stabbing incident. These lesions were managed with endovascular vessel sacrifice via coiling and controlled Onyx injection. Relevant literature was identified via a targeted search of the PubMed database. RESULTS: Post-management angiography demonstrated complete occlusion of the two traumatic PAs and successful disconnection of the concomitant AVF. Our literature review demonstrates a shift in preferred management approach from invasive surgery to endovascular treatment due to the lower risk and cosmetic preferability. CONCLUSION: Timely treatment of enlarging PA is necessary for reducing associated morbidity and mortality. While surgical resection has been the mainstay therapy, endovascular management has gained popularity in recent years. The choice of endovascular technique is variable and should be individualized based on patient's clinical status, associated risk factors, and lesion morphology. We have shown that parent vessel sacrifice is safe and effective. Reconstruction with a combination of stents, coils, glue, or liquid embolics may be necessary when collateral flow is limited.