The Glymphatic System and Subarachnoid Lymphatic-Like Membrane: Recent Developments in Cerebrospinal Fluid Research.

INTRODUCTION: Cerebrospinal fluid (CSF) circulates throughout the ventricles, cranial and spinal subarachnoid spaces, and central spinal cord canal. CSF protects the central nervous system through mechanical cushioning, regulation of intracranial pressure, regulation of metabolic homeostasis, and provision of nutrients. Recently, investigators have characterized the glial-lymphatic (glymphatic) system, the analog of the lymphatic system in the CNS, and described a fourth meningeal layer; the subarachnoid lymphatic-like membrane relevant to the CSF. METHODS: A narrative review was conducted. RESULTS: In this review, we summarize these advances. We describe the development of the original model, controversies, a revised model, and a new conceptual framework. We characterize the biological functions, influence of sleep-wake cycles, and effect of aging with relevance to the glymphatic system. We highlight the role of the glymphatic system in Alzheimer's disease, idiopathic normal pressure hydrocephalus, ischemic stroke, subarachnoid hemorrhage, and traumatic brain injury. Next, we characterize the structure and role of the subarachnoid lymphatic-like membrane. Finally, we explore the relevance of the glymphatic system and subarachnoid lymphatic-like membrane to neurosurgery. CONCLUSION: This manuscript will inform clinicians and scientists regarding preclinical and translational advances in the understanding of the structure, dynamics, and function of the CSF.

Outcome of emergency neurosurgery in patients with refractory and super-refractory status epilepticus: a systematic review and individual participant data meta-analysis.

Background: Refractory (RSE) and super-refractory status epilepticus (SRSE) are serious neurological conditions requiring aggressive management. Beyond anesthetic agents, there is a lack of evidence guiding management in these patients. This systematic review and individual participant data meta-analysis (IPDMA) seeks to evaluate and compare the currently available surgical techniques for the acute treatment of RSE and SRSE. Methods: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Individual Participant Data (PRISMA-IPD). Only patients who underwent surgery while in RSE and SRSE were included. Descriptive statistics were used to compare various subgroups. Multivariable logistic regression models were constructed to identify predictors of status epilepticus (SE) cessation, long-term overall seizure freedom, and favorable functional outcome (i.e., modified Rankin score of 0-2) at last follow-up. Results: A total of 87 studies including 161 participants were included. Resective surgery tended to achieve better SE cessation rate (93.9%) compared to non-resective techniques (83.9%), but this did not reach significance (p = 0.071). Resective techniques were also more likely to achieve seizure freedom (69.1% vs. 34.4%, p = <0.0001). Older age at SE (OR = 1.384[1.046-1.832], p = 0.023) was associated with increased likelihood of SE cessation, while longer duration of SE (OR = 0.603[0.362-1.003], p = 0.051) and new-onset seizures (OR = 0.244[0.069-0.860], p = 0.028) were associated with lower likelihood of SE cessation, but this did not reach significance for SE duration. Only shorter duration of SE prior to surgery (OR = 1.675[1.168-2.404], p = 0.0060) and immediate termination of SE (OR = 3.736 [1.323-10.548], p = 0.014) were independently associated with long-term seizure status. Rates of favorable functional outcomes (mRS of 0-2) were comparable between resective (44.4%) and non-resective (44.1%) techniques, and no independent predictors of outcome were identified. Conclusion: Our findings suggest that emergency neurosurgery may be a safe and effective alternative in patients with RSE/SRSE and may be considered earlier during the disease course. However, the current literature is limited exclusively to small case series and case reports with high risk of publication bias. Larger clinical trials assessing long-term seizure and functional outcomes are warranted to establish robust management guidelines.

Ethical Incorporation of Artificial Intelligence into Neurosurgery: A Generative Pretrained Transformer Chatbot-Based, Human-Modified Approach.

INTRODUCTION: Artificial intelligence (AI) has become increasingly used in neurosurgery. Generative pretrained transformers (GPTs) have been of particular interest. However, ethical concerns regarding the incorporation of AI into the field remain underexplored. We delineate key ethical considerations using a novel GPT-based, human-modified approach, synthesize the most common considerations, and present an ethical framework for the involvement of AI in neurosurgery. METHODS: GPT-4, ChatGPT, Bing Chat/Copilot, You, Perplexity.ai, and Google Bard were queried with the prompt "How can artificial intelligence be ethically incorporated into neurosurgery?". Then, a layered GPT-based thematic analysis was performed. The authors synthesized the results into considerations for the ethical incorporation of AI into neurosurgery. Separate Pareto analyses with 20% threshold and 10% threshold were conducted to determine salient themes. The authors refined these salient themes. RESULTS: Twelve key ethical considerations focusing on stakeholders, clinical implementation, and governance were identified. Refinement of the Pareto analysis of the top 20% most salient themes in the aggregated GPT outputs yielded 10 key considerations. Additionally, from the top 10% most salient themes, 5 considerations were retrieved. An ethical framework for the use of AI in neurosurgery was developed. CONCLUSIONS: It is critical to address the ethical considerations associated with the use of AI in neurosurgery. The framework described in this manuscript may facilitate the integration of AI into neurosurgery, benefitting both patients and neurosurgeons alike. We urge neurosurgeons to use AI only for validated purposes and caution against automatic adoption of its outputs without neurosurgeon interpretation.

Opportunities and Considerations for the Incorporation of Artificial Intelligence into Global Neurosurgery: A Generative Pretrained Transformer Chatbot-Based Approach.

OBJECTIVE: Global neurosurgery is a public health focus in neurosurgery that seeks to ensure safe, timely, and affordable neurosurgical care to all individuals worldwide. Although investigators have begun to explore the promise of artificial intelligence (AI) for neurosurgery, its applicability to global neurosurgery has been largely hypothetical. We characterize opportunities and considerations for the incorporation of AI into global neurosurgery by synthesizing key themes yielded from a series of generative pretrained transformers (GPTs), discuss important limitations of GPTs and cautions when using AI in neurosurgery, and develop a framework for the equitable incorporation of AI into global neurosurgery. METHODS: ChatGPT, Bing Chat/Copilot, You, Perplexity.ai, and Google Bard were queried with the prompt "How can AI be incorporated into global neurosurgery?" A layered ChatGPT-based thematic analysis was performed. The authors synthesized the results into opportunities and considerations for the incorporation of AI in global neurosurgery. A Pareto analysis was conducted to determine common themes. RESULTS: Eight opportunities and 14 important considerations were synthesized. Six opportunities related to patient care, 1 to education, and another to public health planning. Four of the important considerations were deemed specific to global neurosurgery. The Pareto analysis included all 8 opportunities and 5 considerations. CONCLUSIONS: AI may be incorporated into global neurosurgery in a variety of capacities requiring numerous considerations. The framework presented in this manuscript may facilitate the incorporation of AI into global neurosurgery initiatives while balancing contextual factors and the reality of limited resources.

The impact of social determinants of health on utilization of pediatric epilepsy surgery: a systematic review.

OBJECTIVE: A minority of pediatric patients who may benefit from epilepsy surgery receive it. The reasons for this utilization gap are complex and not completely understood. Patient and caregiver social determinants of health (SDOH) may impact which patients undergo surgery and when. The authors conducted a systematic review examining SDOH and surgical intervention in children with drug-resistant epilepsy (DRE). They aimed to understand which factors influenced time to surgical program referral or receipt of epilepsy surgery among children with DRE, as well as identify areas to characterize the SDOH impacting epilepsy surgery in children and guide efforts aimed to promote health equity in epilepsy. METHODS: A systematic review was conducted using the PubMed, Embase, and Scopus databases in January 2022. Studies were analyzed by title and abstract, then full text, to identify all studies examining the impact of SDOH on utilization of epilepsy surgery. Studies meeting inclusion criteria were analyzed for SDOH examined, outcomes, and key findings. Quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: Of 4545 resultant articles, 18 were included. Studies examined social, cultural, and environmental factors that contributed to SDOH impacting epilepsy surgery. Patients who underwent surgical evaluation were found to be most commonly White and privately insured and have college-educated caregivers. Five studies found differences in time to referral/surgery or rates of surgery by racial group, with most finding an increased time to referral/surgery or lower rates of surgery for those who were Hispanic and/or non-White. Four studies found that private insurance was associated with higher surgical utilization. Three studies found higher household income was related to surgical utilization. No studies examined biological, psychological, or behavioral factors that contributed to SDOH impacting epilepsy surgery. CONCLUSIONS: The authors conducted a systematic review exploring the impact of SDOH in DRE surgery utilization. They found that race, ethnicity, insurance type, caregiver educational attainment, and household income demonstrate relationships with pediatric epilepsy surgery. Further study is necessary to understand how these factors, and others not identified in this study, contribute to the low rates of utilization of epilepsy surgery and potential target areas for interventions aiming to increase equity in access to epilepsy surgery in children.

Surgical management of spinal metastases from primary thyroid carcinoma: Demographics, clinical characteristics, and treatment outcomes - A retrospective analysis.

Objective: Metastatic spinal tumors represent a rare but concerning complication of primary thyroid carcinoma. We identified demographics, metastatic features, outcomes, and treatment strategies for these tumors in our institutional cohort. Materials and Methods: We retrospectively reviewed patients surgically treated for spinal metastases of primary thyroid carcinoma. Demographics, tumor characteristics, and treatment modalities were collected. The functional outcomes were quantified using Nurik, Modified Rankin, and Karnofsky Scores. Results: Twelve patients were identified who underwent 17 surgeries for resection of spinal metastases. The primary thyroid tumor pathologies included papillary (4/12), follicular (6/12), and Hurthle cell (2/12) subtypes. The average number of spinal metastases was 2.5. Of the primary tumor subtypes, follicular tumors averaged 2.8 metastases at the highest and Hurthle cell tumors averaged 2.0 spinal metastases at the lowest. Five patients (41.7%) underwent preoperative embolization for their spinal metastases. Seven patients (58.3%) received postoperative radiation. There was no significant difference in progression-free survival between patients receiving surgery with adjuvant radiation and surgery alone (P = 0.0773). Five patients (41.7%) experienced postoperative complications. Two patients (16.7%) succumbed to disease progression and two patients (16.7%) experienced tumor recurrence following resection. Postsurgical mean Nurik scores decreased 0.54 points, mean Modified Rankin scores decreased 0.48 points, and mean Karnofsky scores increased 4.8 points. Conclusion: Surgery presents as an important treatment modality in the management of spinal metastases from thyroid cancer. Further work is needed to understand the predictive factors for survival and outcomes following treatment.

The demographic, clinical, and management differences between traumatic dens fracture patients with and without simultaneous atlas fractures.

Introduction: Atlas fractures often accompany traumatic dens fractures, but existing literature on the management of simultaneous atlantoaxial fractures is limited. Methods: We examined all patients with traumatic dens fractures at our institution between 2008 and 2018. We used multivariable logistic regression and ordinal logistic regression to identify factors independently associated with presentation with a simultaneous atlas fracture, as well myelopathy severity, fracture nonunion, and selection for surgery. Results: Two hundred and eighty-two patients with traumatic dens fractures without subaxial fractures were identified, including 65 (22.8%) with simultaneous atlas fractures. The distribution of injury mechanisms differed between groups (χ2 P = 0.0360). On multivariable logistic regression, dens nonunion was positively associated with type II fractures (odds ratio [OR] = 2.00, P = 0.038) and negatively associated with having surgery (OR = 0.52, P = 0.049), but not with having a C1 fracture (P = 0.3673). Worse myelopathy severity on presentation was associated with having a severe injury severity score (OR = 102.3, P < 0.001) and older age (OR = 1.28, P = 0.002), but not with having an atlas fracture (P = 0.2446). Having a simultaneous atlas fracture was associated with older age (OR = 1.29, P = 0.024) and dens fracture angulation (OR = 2.62, P = 0.004). Among patients who underwent surgery, C1/C2 posterior fusion was the most common procedure, and having a simultaneous atlas fracture was associated with selection for occipitocervical fusion (OCF) (OR = 14.35, P = 0.010). Conclusions: Among patients with traumatic dens, patients who have simultaneous atlas fractures are a distinct subpopulation with respect to age, mechanism of injury, fracture morphology, and management. Traumatic dens fractures with simultaneous atlas fractures are independently associated with selection for OCF rather than posterior cervical fusion alone.

Visual outcomes after treatment of craniopharyngioma in children: A systematic review.

OBJECTIVE: Craniopharyngiomas (CP) are rare brain tumors that often result in visual impairment due to their proximity to the optic pathway. The optimal management approach to preserve visual function in these patients remains controversial. We sought to investigate visual outcomes of children with craniopharyngiomas based on treatment modality. METHODS: A systematic review was performed according to PRISMA guidelines. PubMed, Embase, and Scopus databases were searched in December 2022 for relevant articles. Articles were screened by title/abstract for relevance, then by full-text. Relevant demographic, intervention, and outcome data were extracted from included studies. RESULTS: A total of 59 studies were included, representing 2655 patients. The overall visual status (OVS) of patients receiving surgery alone was improved in 27.6% of reported outcomes, unchanged in 50.3%, and deteriorated in 22.1%. The OVS for patients receiving radiation alone was improved in 21.1%, unchanged in 42.1%, and deteriorated in 36.8%. Patients receiving surgery plus adjuvant radiotherapy had OVS improvement in 27.4%, unchanged in 63.2%, and deteriorated in 9.4%. Of those receiving intracystic bleomycin, 23.1% had improvement in OVS, 46.2% remained unchanged, and 30.8% deteriorated. Of patients receiving interferon-α, 34.8% improved, 54.5% remained unchanged, and 10.6% deteriorated. CONCLUSION: OVS most frequently remained unchanged regardless of intervention. The greatest improvement in OVS was seen in those receiving interferon-α or surgery alone. The greatest OVS deterioration was noted with radiation alone. Future standardized, randomized, large-scale studies with focused assessment of ophthalmologic findings are key to further understanding the impact different interventions have on visual outcomes in these children.

Hemimegalencephaly: A Systematic Comparison of Functional and Anatomic Hemispherectomy for Drug-Resistant Epilepsy.

BACKGROUND AND OBJECTIVES: Hemimegalencephaly (HME) is a rare diffuse malformation of cortical development characterized by unihemispheric hypertrophy, drug-resistant epilepsy (DRE), hemiparesis, and developmental delay. Definitive treatment for HME-related DRE is hemispheric surgery through either anatomic (AH) or functional hemispherectomy (FH). This individual patient data meta-analysis assessed seizure outcomes of AH and FH for HME with pharmacoresistant epilepsy, predictors of Engel I, and efficacy of different FH approaches. METHODS: PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health Literature were searched from inception to Jan 13th, 2023, for primary literature reporting seizure outcomes in >3 patients with HME receiving AH or FH. Demographics, neurophysiology findings, and Engel outcome at the last follow-up were extracted. Postsurgical seizure outcomes were compared through 2-tailed t -test and Fisher exact test. Univariate and multivariate Cox regression analyses were performed to identify independent predictors of Engel I outcome. RESULTS: Data from 145 patients were extracted from 26 studies, of which 89 underwent FH (22 vertical, 33 lateral), 47 underwent AH, and 9 received an unspecified hemispherectomy with a median last follow-up of 44.0 months (FH cohort) and 45.0 months (AH cohort). Cohorts were similar in preoperative characteristics and at the last follow-up; 77% (n = 66) of the FH cohort and 81% (n = 38) and of the AH cohort were Engel I. On multivariate analysis, only the presence of bilateral ictal electroencephalography abnormalities (hazard ratio = 11.5; P = .002) was significantly associated with faster time-to-seizure recurrence. A number-needed-to-treat analysis to prevent 1 additional case of posthemispherectomy hydrocephalus reveals that FH, compared with AH, was 3. There was no statistical significance for any differences in time-to-seizure recurrence between lateral and vertical FH approaches (hazard ratio = 2.59; P = .101). CONCLUSION: We show that hemispheric surgery is a highly effective treatment for HME-related DRE. Unilateral ictal electroencephalography changes and using the FH approach as initial surgical management may result in better outcomes due to significantly lower posthemispherectomy hydrocephalus probability. However, larger HME registries are needed to further delineate the predictors of seizure outcomes.

Surgical Outcome of Patients With Supratentorial Meningiomas Aged 80 Years or Older-Retrospective International Multicenter Study.

BACKGROUND AND OBJECTIVES: Demographic changes will lead to an increase in old patients, a population with significant risk of postoperative morbidity and mortality, requiring neurosurgery for meningiomas. This multicenter study aims to report neurofunctional status after resection of patients with supratentorial meningioma aged 80 years or older, to identify factors associated with outcome, and to validate a previously proposed decision support tool. METHODS: Neurofunctional status was assessed by the Karnofsky Performance Scale (KPS). Patients were categorized in poor (KPS ≤40), intermediate (KPS 50-70), and good (KPS ≥80) preoperative subgroups. Volumetric analyses of tumor and peritumoral brain edema (PTBE) were performed; volumes were scored as small (<10 cm 3 ), medium (10-50 cm 3 ), and large (>50 cm 3 ). RESULTS: The study population consisted of 262 patients, and the median age at surgery was 83.0 years. The median preoperative KPS was 70; 117 (44.7%) patients were allotted to the good, 113 (43.1%) to the intermediate, and 32 (12.2%) to the poor subgroup. The median tumor and PTBE volumes were 30.2 cm 3 and 27.3 cm 3 ; large PTBE volume correlated with poor preoperative KPS status ( P = .008). The 90-day and 1-year mortality rates were 9.0% and 13.2%, respectively. Within the first postoperative year, 101 (38.5%) patients improved, 87 (33.2%) were unchanged, and 74 (28.2%) were functionally worse (including deaths). Each year increase of age associated with 44% (23%-70%) increased risk of 90-day and 1-year mortality. In total, 111 (42.4%) patients suffered from surgery-associated complications. Maximum tumor diameter ≥5 cm (odds ratio 1.87 [1.12-3.13]) and large tumor volume (odds ratio 2.35 [1.01-5.50]) associated with increased risk of complications. Among patients with poor preoperative status and large PTBE, most (58.3%) benefited from surgery. CONCLUSION: Patients with poor preoperative neurofunctional status and large PTBE most often showed postoperative improvements. The decision support tool may be of help in identifying cases that most likely benefit from surgery.

Cataloging formal medical student surgical funding opportunities: A retrospective characterization.

Representation of female surgical residents has slowly increased, but underrepresented in medicine (URiM) representation remains disappointingly low. National residency matching reports suggest that meaningful research experience improves surgical residency match success - therefore, formal funding opportunities and early mentorship for URiM medical students. In this study, we catalog medical student (MS) funding opportunities (funding type, eligibility by year, mission, compensation, length of commitment, number of awardees, and dollar investment amount per student) from 7 surgical departments (general surgery, thoracic surgery, vascular surgery, plastic surgery, otorhinolaryngology, orthopedic surgery, neurosurgery) within 196 US medical schools and 20 professional surgical educational organizations through manually searching web pages. We recorded 146 surgical funding opportunities from medical school surgical departments and 16 surgical funding opportunities from professional organizations. Overall, we find that medical institutions' surgical departments and professional surgical educational organizations may not be effectively utilizing recruitment strategies in MS funding opportunities.

Survival and neurological outcomes after stereotactic biopsy of diffuse intrinsic pontine glioma: a systematic review.

OBJECTIVE: Diffuse intrinsic pontine gliomas (DIPGs) are aggressive and malignant tumors of the brainstem. Stereotactic biopsy can obtain molecular and genetic information for diagnostic and potentially therapeutic purposes. However, there is no consensus on the safety of biopsy or effect on survival. The authors aimed to characterize neurological risk associated with and the effect of stereotactic biopsy on survival among patients with DIPGs. METHODS: A systematic review was performed in accordance with PRISMA guidelines to identify all studies examining pediatric patients with DIPG who underwent stereotactic biopsy. The search strategy was deployed in PubMed, Embase, and Scopus. The quality of studies was assessed using the Grading of Recommendations, Assessment, Development and Evaluation system, and risk of bias was evaluated with the Cochrane Risk of Bias in Nonrandomized Studies-of Interventions tool. Bibliographic, demographic, clinical, and outcome data were extracted from studies meeting inclusion criteria. RESULTS: Of 2634 resultant articles, 13 were included, representing 192 patients undergoing biopsy. The weighted mean age at diagnosis was 7.5 years (range 0.5-17 years). There was an overall neurosurgical complication rate of 13.02% (25/192). The most common neurosurgical complication was cranial nerve palsy (4.2%, 8/192), of which cranial nerve VII was the most common (37.5%, 3/8). The second most common complication was perioperative hemorrhage (3.6%, 7/192), followed by hemiparesis (2.1%, 4/192), speech disorders (1.6%, 3/192) such as dysarthria and dysphasia, and movement disorders (1.0%, 2/192). Hydrocephalus was less commonly reported (0.5%, 1/192), and there were no complications relating to wound infection/dehiscence (0%, 0/192) or CSF leak (0%, 0/192). No mortality was specifically attributed to biopsy. Diagnostic yield of biopsy revealed a weighted mean of 97.4% (range 91%-100%). Of the studies reporting survival data, 37.6% (32/85) of patients died within the study follow-up period (range 2 weeks-48 months). The mean overall survival in patients undergoing biopsy was 9.73 months (SD 0.68, median 10 months, range 6-13 months). CONCLUSIONS: Children with DIPGs undergoing biopsy have mild to moderate rates of neurosurgical complications and no excessive morbidity. With reasonably acceptable surgical risk and high diagnostic yield, stereotactic biopsy of DIPGs can allow for characterization of patient-specific molecular and genetic features that may influence prognosis and the development of future therapeutic strategies.

The Greatest Healthcare Disparity: Addressing Inequities in the Treatment of Childhood Central Nervous System Tumors in Low- and Middle-Income Countries.

The antithesis between childhood cancer survival rates in low- and middle-income countries (LMIC) and high-income countries (HIC) represents one of healthcare's most significant disparities. In HICs, the 5-year survival rate for children with cancer, including most brain tumors, exceeds 80%. Unfortunately, children in LMICs experience far worse outcomes with 5-year survival rates as low as 20%. To address inequities in the treatment of childhood cancer and disease burden globally, the World Health Organization (WHO) launched the Global Initiative for Childhood Cancer. Within this initiative, pediatric low-grade glioma (LGG) represents a unique opportunity for the neurosurgical community to directly contribute to a paradigm shift in the survival outcomes of children in LMICs, as many of these tumors can be managed with surgical resection alone. In this chapter, we discuss the burden of pediatric LGG and outline actions the neurosurgical community might consider to improve survival for children with LGG in LMICs.

Global Epidemiology of Pediatric Traumatic Spine Injury: A Systematic Review and Meta-Analysis.

OBJECTIVE: Traumatic spine injury (TSI) leads to significant morbidity and mortality in children. However, the global epidemiology of pediatric TSI is currently unknown. We conducted a systematic review and meta-analysis to estimate the global incidence of pediatric TSI and the burden of cases. METHODS: PubMed, Embase, and Scopus were searched for reports in June 2021 and updated in March 2023 with no restrictions on language or year of publication. A meta-analysis was conducted to estimate the global incidence of pediatric TSI and, subsequently, the number of cases of pediatric TSI worldwide and the proportion requiring spine surgery. RESULTS: Of 6557 studies, 25 met the inclusion criteria. Road traffic accidents (64%) were responsible for most cases reported in the literature, followed by falls (18%). The global incidence of TSI in children aged ≤20 years was estimated to be 14.24 of 100,000 children, or 375,734 children, with an estimated 114,975 requiring spine surgery. Across the World Bank income classification groups, lower middle-income countries had the highest pediatric TSI case burden (186,886 cases, with 57,187 requiring spine surgery). Across the World Health Organization regions, countries in the Southeast Asia region had the largest number of projected cases at 88,566, with 27,101 requiring surgical management, followed closely by the African region, with 87,235 projected cases and 26,694 requiring surgical management. CONCLUSIONS: Pediatric TSI represents a large healthcare burden globally. Interventions targeting both injury prevention and strengthening of neurosurgical capacity, especially in low resource settings, are needed to address this global health challenge.

Post-Surgical Cognitive Outcomes of Moyamoya Disease: A Systematic Review.

BACKGROUND: Moyamoya disease (MMD) is an occlusive arteriopathy leading to stroke. Progressive if left untreated, revascularization surgery has become the mainstay of treatment. Although clinical and radiographic outcomes of MMD after intervention are well-characterized, cognitive outcomes in pediatric patients remain unclear. We aimed to examine postoperative cognitive outcomes in children with MMD, examine factors associated with cognitive changes after intervention, and define the effect of revascularization surgery on cognitive outcomes. METHODS: A systematic review was conducted following PRISMA guidelines searching PubMed, Embase, and Scopus databases. Articles met inclusion criteria if they studied pediatric patients undergoing revascularization surgery for MMD and examined cognitive outcomes either qualitatively or quantitatively. All data extracted from included articles was examined descriptively. RESULTS: Of 1091 resultant articles, 12 articles containing 446 patients were included. Surgery was associated with maintained or improved full scale intellectual quotient (IQ), performance IQ, perceptual IQ, memory quotient and verbal memory. However, 70% of patients had impaired cognitive function, with associated poor school performance. Improvements in cognition were associated with increased cerebral blood flow, particularly to the middle cerebral artery, due to the development of collaterals. Female sex, shorter duration from symptom onset to surgery, and surgery after age 7 were predictive of cognitive improvement. Completed ischemic stroke prior to surgery was associated with poorer cognitive outcomes. CONCLUSIONS: Although children with MMD have improved cognitive outcomes following revascularization overall, a distinct subset experience cognitive impairment. Consideration of patient-specific and treatment-related factors is important to enable proper risk stratification and inform management approaches.

Surgery Decreases Nonunion, Myelopathy, and Mortality for Patients With Traumatic Odontoid Fractures: A Propensity Score Matched Analysis.

BACKGROUND: Existing literature suggests that surgical intervention for odontoid fractures is beneficial but often does not control for known confounding factors. OBJECTIVE: To examine the effect of surgical fixation on myelopathy, fracture nonunion, and mortality after traumatic odontoid fractures. METHODS: We analyzed all traumatic odontoid fractures managed at our institution between 2010 and 2020. Ordinal multivariable logistic regression was used to identify factors associated with myelopathy severity at follow-up. Propensity score analysis was used to test the treatment effect of surgery on nonunion and mortality. RESULTS: Three hundred and three patients with traumatic odontoid fracture were identified, of whom 21.6% underwent surgical stabilization. After propensity score matching, populations were well balanced across all analyses (Rubin's B < 25.0, 0.5 < Rubin's R < 2.0). Controlling for age and fracture angulation, type, comminution, and displacement, the overall rate of nonunion was lower in the surgical group (39.7% vs 57.3%, average treatment effect [ATE] = -0.153 [-0.279, -0.028], P = .017). Controlling for age, sex, Nurick score, Charlson Comorbidity Index, Injury Severity Score, and selection for intensive care unit admission, the mortality rate was lower for the surgical group at 30 days (1.7% vs 13.8%, ATE = -0.101 [-0.172, -0.030], P = .005) and at 1 year was 7.0% vs 23.7%, ATE = -0.099 [-0.181, -0.017], P = .018. Cox proportional hazards analysis also demonstrated a mortality benefit for surgery (hazard ratio = 0.587 [0.426, 0.799], P = .0009). Patients who underwent surgery were less likely to have worse myelopathy scores at follow-up (odds ratio = 0.48 [0.25, 0.93], P = .029). CONCLUSION: Surgical stabilization is associated with better myelopathy scores at follow-up and causes lower rates of fracture nonunion, 30-day mortality, and 1-year mortality.

The World Neurosurgery Global Champions Program: First-Year Experience of a Model Initiative for Reducing Disparities in Global Neurosurgical Literature.

OBJECTIVE: Most surgical journals are published in English, representing a challenge for researchers from non-Anglophone countries. We describe the implementation, workflow, outcomes, and lessons learned from the WORLD NEUROSURGERY Global Champions Program (GCP), a novel journal-specific English language editing program for articles rejected because of poor English grammar or usage. METHODS: The GCP was advertised via the journal website and social media. Applicants were selected to be a reviewer for the GCP if they demonstrated English proficiency on writing samples supplied in their application. The demographics of GCP members and characteristics and outcomes of articles edited by the GCP during its first year were reviewed. Surveys of GCP members and authors who used the service were conducted. RESULTS: Twenty-one individuals became part of the GCP, representing 8 countries and 16 languages apart from English. A total of 380 manuscripts were peer reviewed by the editor-in-chief, who determined these manuscripts to have potentially worthwhile content but needed to be rejected due to poor language. The authors of these manuscripts were informed of the existence of this language assistance program. Forty-nine articles (12.9%) were edited by the GCP in 41.6 ± 22.8 days. Of 40 articles resubmitted to WORLD NEUROSURGERY, 24 (60.0%) were accepted. GCP members and authors understood the purpose and workflow of the program and recognized improvements in article quality and the probability of acceptance through their participation. CONCLUSIONS: The WORLD NEUROSURGERY Global Champions Program mitigated a critical barrier to publication in an English language journal for authors from non-Anglophone countries. This program promotes research equity by providing a free, largely medical student and trainee operated, English language editing service. This model or a similar service can be replicated by other journals.

Vasospasm following brain tumor resection in children: institutional experience and systematic review.

OBJECTIVE: Delayed cerebral ischemia (DCI) associated with vasospasm is well described in the setting of aneurysmal subarachnoid hemorrhage (SAH). In addition, DCI is very infrequently encountered in patients who have undergone resection of a brain tumor with unclear pathophysiology. The occurrence of DCI in the pediatric population is exceedingly rare, and outcomes in this population have, to the authors' knowledge, never been systematically reviewed. Therefore, the authors present what is to their knowledge the largest series of pediatric patients with this complication and systematically reviewed the literature for individual participant data. METHODS: The authors conducted a retrospective review of 172 sellar and suprasellar tumors in pediatric patients who underwent surgery at the Montreal Children's Hospital between 1999 and 2017 to identify cases of vasospasm occurring after tumor resection. Descriptive statistics, including patient characteristics, intraoperative and postoperative findings, and outcome status, were collected. A systematic review was also conducted using three databases (PubMed, Web of Science, Embase) to identify reported cases available in the literature of vasospasm after tumor resection in children and collect individual participant data on these patients for further analysis. RESULTS: Six patients treated at Montreal Children's Hospital were identified, with an average age of 9.5 years (range 6-15 years). The prevalence of vasospasm after tumor resection was 3.5% (6/172). Vasospasm in all 6 patients occurred after craniotomy was performed to treat a suprasellar tumor. The average interval from surgery to symptoms was 3.25 days (range 12 hours-10 days). The most common tumor etiology was craniopharyngioma, seen in 4 cases. Extensive tumor encasement of blood vessels requiring significant operative manipulation was described in all 6 patients. A rapid decrease in serum sodium (exceeding 12 mEq/L/24 hrs or below 135 mEq/L) was seen in 4 patients. On final follow-up, 3 patients were left with significant disability, and all patients had persistent deficits. A systematic review of the literature revealed a total of 10 other patients whose characteristics and treatment were compared with those of the 6 patients treated at Montreal Children's Hospital. CONCLUSIONS: Vasospasm after tumor resection in children and youth is likely a rare entity, with a prevalence of 3.5% in this case series. Suprasellar tumor location (particularly craniopharyngioma tumor etiology), significant encasement of blood vessels by the tumor, and postoperative hyponatremia may be predictive factors. Outcome is poor, with most patients having significant persistent neurological deficits.

Functional Anatomy and Biomechanics of the Craniovertebral Junction.

The craniovertebral junction (CVJ) involves the atlas, axis, and occiput along with the atlanto-occipital and atlantoaxial joints. The anatomy and neural and vascular anatomy of the junction render the CVJ unique. Specialists treating disorders that affect the CVJ must appreciate its intricate anatomy and should be well versed in its biomechanics. This first article in a three-article series provides an overview of the functional anatomy and biomechanics of the CVJ.