Neurosurgical Management of Myelomeningocele in Premature Infants: A Case Series.

Introduction Myelomeningocele (MMC) is the most common neural tube defect, but rarely seen in premature infants. Most centers advocate for closure of MMC within 24 hours of birth. However, this is not always possible in severely premature infants. Given the rarity of this patient population, we aimed to share our institutional experience and outcomes of severely premature infants with MMC. Methods We performed a retrospective, observational review of premature infants (≤ 32 weeks gestational age) identified through our multidisciplinary spina bifida clinic (1995-2021) and surgical logs. Descriptive statistics were compiled about this sample including timing of MMC closure and incidence of adverse events such as sepsis, CSF diversion, meningitis, and death. Results Eight patients were identified (50% male) with MMC who were born ≤ 32 weeks gestational age. Mean gestational age of the population was 27.3 weeks (SD 3.5). Median time to MMC closure was 1.5 days (IQR = 1-80.8). Five patients were taken for surgery within the recommended 48 hours of birth; 2 patients underwent significantly delayed closure (107 and 139 days); and one patient's defect epithelized without surgical intervention. Six of eight patients required permanent cerebrospinal fluid (CSF) diversion (2 patients were treated with ventriculoperitoneal shunting (VPS), three were treated with endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) and 1 patient treated with ETV; mean of 3 years after birth, ranging from 1 day to 16 years). Two patients required more than one permanent CSF diversion procedure. Two patients developed sepsis (defined as meeting at least 2/4 SIRS criteria), and 2 patients had intraventricular hemorrhage (both grade III). No patients developed meningitis (defined as positive CSF cultures) prior to MMC closure. Median follow up duration was 9.7 years. During this time epoch, 3 patients died: Two before 2 years of age of causes unrelated to surgical intervention. One of the two patients with grade III IVH died within 24 hours of MMC closure. Conclusions In our institutional experience with premature infants with MMC, some patients underwent delayed MMC closure. The overall rate of meningitis, sepsis, and mortality for preterm children with MMC was similar to MMC patients born at term.

The role of occipital condyle and atlas anomalies on occipital cervical fusion outcomes in Chiari malformation type I with syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF). METHODS: The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio. RESULTS: Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95). CONCLUSIONS: The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Pediatric non-galenic pial arteriovenous fistula's characteristics and outcomes: a systematic review.

INTRODUCTION: Pediatric non-galenic pial arteriovenous fistulas (pAVFs) are rare vascular malformations that are characterized by a pial arterial-venous connection without an intervening capillary bed. Outcomes and treatment strategies for pAVFs are highly individualized, owing to the rarity of the disease and lack of large-scale data guiding optimal treatment approaches. METHODS: We performed a systematic review of pediatric patients (< 18 years at diagnosis) diagnosed with a pAVF by digital subtraction angiogram (DSA). The demographics, treatment modalities, and outcomes were documented for each patient and clinical outcome data was collected. Descriptive information stratified by outcome scores were classified as follows: 1 = excellent (no deficit and full premorbid activity), 2 = good (mild deficit and full premorbid activity), 3 = fair (moderate deficit and impaired activity), 4 = poor (severe deficit and dependent on others), 5 = death. RESULTS: A total of 87 studies involving 231 patients were identified. Median age at diagnosis was 3 years (neonates to 18 years). There was slight male preponderance (55.4%), and 150 subjects (81.1%*) experienced excellent outcomes after treatment. Of the 189 patients treated using endovascular approaches, 80.3% experienced excellent outcomes and of the 15 patients surgically treated subjects 75% had an excellent outcome. The highest rate of excellent outcomes was achieved in patients treated with Onyx (95.2%) and other forms of EvOH (100%). High output heart failure and comorbid vascular lesions tended to result in worse outcomes, with only 54.2% and 68% of subjects experiencing an excellent outcome, respectively. *Outcomes were reported in only 185 patients. CONCLUSION: pAVFs are rare lesions, necessitating aggregation of patient data to inform natural history and optimal treatment strategies. This review summarizes the current literature on pAVF in children, where children presenting with heart failure as a result of high flow through the lesion were less likely to experience an excellent outcome. Prospective, large-scale studies would further characterize pediatric pAVFs and enable quantitative analysis of outcomes to inform best treatment practices.

The genetic basis of hydrocephalus: genes, pathways, mechanisms, and global impact.

Hydrocephalus (HC) is a heterogenous disease characterized by alterations in cerebrospinal fluid (CSF) dynamics that may cause increased intracranial pressure. HC is a component of a wide array of genetic syndromes as well as a secondary consequence of brain injury (intraventricular hemorrhage (IVH), infection, etc.) that can present across the age spectrum, highlighting the phenotypic heterogeneity of the disease. Surgical treatments include ventricular shunting and endoscopic third ventriculostomy with or without choroid plexus cauterization, both of which are prone to failure, and no effective pharmacologic treatments for HC have been developed. Thus, there is an urgent need to understand the genetic architecture and molecular pathogenesis of HC. Without this knowledge, the development of preventive, diagnostic, and therapeutic measures is impeded. However, the genetics of HC is extraordinarily complex, based on studies of varying size, scope, and rigor. This review serves to provide a comprehensive overview of genes, pathways, mechanisms, and global impact of genetics contributing to all etiologies of HC in humans.

The safety and accuracy of intratumoral catheter placement to infuse viral immunotherapies in children with malignant brain tumors: a multi-institutional study.

OBJECTIVE: Relatively little is known about the safety and accuracy of catheter placement for oncolytic viral therapy in children with malignant brain tumors. Accordingly, this study combines data from two phase I clinical trials that employed viral immunotherapy across two institutions to describe the adverse event profile, safety, and accuracy associated with the stereotactic placement and subsequent removal of intratumoral catheters. METHODS: Children with progressive/recurrent supratentorial malignant tumors were enrolled in two clinical trials (NCT03043391 and NCT02457845) and treated with either the recombinant polio:rhinovirus (lerapolturev) or the genetically modified oncolytic herpesvirus (G207). Age, sex, race, tumor diagnosis, and tumor location were analyzed. Events related to the catheter placement or removal were categorized. A catheter that was either pulled back or could not be used was defined as "misplaced." Neuronavigation software was used to analyze the accuracy of catheter placement for NCT03043391. Descriptive statistics were performed. RESULTS: Nineteen patients were treated across the two completed trials with a total of 49 catheters. The mean ± SD (range) age was 14.1 ± 3.6 (7-19) years. All tumors were grade 3 or 4 gliomas. Nonlobar catheter tip placement included the corpus callosum, thalamus, insula, and cingulate gyrus. Six of 19 patients (31.6%) had minor hemorrhage noted on CT; however, no patients were symptomatic and/or required intervention related to these findings. One of 19 patients had a delayed CSF leak after catheter removal that required oversewing of the surgical site. No patients developed infection or a neurological deficit. In 7 patients with accuracy data, the mean ± SD distance of the planned trajectory (PT) to the catheter tip was 1.57 ± 1.6 mm, the mean angle of the PT to the catheter was 2.43° ± 2.1°, and the greatest distance of PT to the catheter in the parallel plane was 1.54 ± 1.5 mm. Three of 49 (6.1%) catheters were considered misplaced. CONCLUSIONS: Although instances of minor hemorrhage were encountered, they were clinically asymptomatic. One of 49 catheters required intervention for a CSF leak. Congruent with previous studies in the literature, the stereotactic placement of catheters in these pediatric tumor patients was accurate with approximately 95% of catheters having been adequately placed.

Characteristics and outcomes of pediatric dural arteriovenous fistulas: a systematic review.

BACKGROUND: Dural arteriovenous fistulas (dAVF) are arteriovenous shunts in communication with the dural vasculature in the brain or spine. Apart from single-center series, risk factors and treatment outcomes for pediatric dAVFs are largely undescribed. METHODS: We performed a systematic literature review of pediatric (< 18 years at diagnosis) intracranial and spinal dAVF according to PRISMA guidelines. We queried PubMed, CINAHL, SCOPUS, and Embase databases without time/date restriction. Search strings included a variety of MeSH keywords relating to dural AV fistulas in combination with MeSH keywords related to pediatric cases (see Appendix). Manuscripts describing patients diagnosed with dural sinus malformations or pial AVF were excluded. RESULTS: We identified 61 studies describing 69 individual patients. Overall, dAVF were more common in males (55.1%) with a mean age of diagnosis (5.17 ± 4.42 years). Approximately 20.2% of patients presented with cardiovascular disease (CVD), and 31.9% were discovered incidentally on neuroimaging studies. Transverse-sigmoid junction was the most common location (17.3%). Ninety-three percent (64 patients) were treated, most commonly using endovascular embolization (68.1%) followed by surgery (8.7%) and radiosurgery (2.9%). Almost half (43.8%) of dAVFs were completely obliterated. Of the 64 procedures, there were 19 neurological complications (29.7%) of varying severity where 12.5% were considered transient (i.e., pseudomeningocele) and 17.2% permanent (i.e., mortality secondary to acute sinus thrombosis, etc.). CONCLUSION: There is a paucity of information on pediatric dAVFs. This systematic review summarizes the published cases of dAVFs in the pediatric population. While the rate of missing data is high, there is publication bias, and precise details regarding complications are difficult to ascertain, this review serves as a descriptive summary of pediatric dAVFs.

Optimizing Surgical Efficiency in Complex Spine Surgery Using Virtual Reality as a Communication Technology to Promote a Shared Mental Model: A Case Series and Review.

BACKGROUND AND OBJECTIVES: Virtual reality (VR) is an emerging technology that can be used to promote a shared mental model among a surgical team. We present a case series demonstrating the use of 3-dimensional (3D) VR models to visually communicate procedural steps to a surgical team to promote a common operating objective. We also review the literature on existing uses of VR for preoperative communication and planning in spine surgery. METHODS: Narrations of 3 to 4-minute walkthroughs were created in a VR visualization platform, converted, and distributed to team members through text and email the night before surgical intervention. A VR huddle was held immediately before the intervention to refine surgical goals. After the intervention, the participating team members' perceptions on the value of the tool were assessed using a survey that used a 5-point Likert scale. MEDLINE, Google Scholar, and Dimensions AI databases were queried from July 2010 to October 2022 to examine existing literature on preoperative VR use to plan spine surgery. RESULTS: Three illustrative cases are presented with accompanying video. Postoperative survey results demonstrate a positive experience among surgical team members after reviewing preoperative plans created with patient-specific 3D VR models. Respondents felt that preoperative VR video review was "moderately useful" or more useful in improving their understanding of the operational sequence (71%, 5/7), in enhancing their ability to understand their role (86%, 6/7), and in improving the safety or efficiency of the case (86%, 6/7). CONCLUSION: We present a proof of concept of a novel preoperative communication tool used to create a shared mental model of a common operating objective for surgical team members using narrated 3D VR models. Initial survey results demonstrate positive feedback among respondents. There is a paucity of literature investigating VR technology as a means for preoperative surgical communication in spine surgery. ETHICS: Institutional review board approval (IRB-300009785) was obtained before this study.

Mutation of key signaling regulators of cerebrovascular development in vein of Galen malformations.

To elucidate the pathogenesis of vein of Galen malformations (VOGMs), the most common and most severe of congenital brain arteriovenous malformations, we performed an integrated analysis of 310 VOGM proband-family exomes and 336,326 human cerebrovasculature single-cell transcriptomes. We found the Ras suppressor p120 RasGAP (RASA1) harbored a genome-wide significant burden of loss-of-function de novo variants (2042.5-fold, p = 4.79 x 10-7). Rare, damaging transmitted variants were enriched in Ephrin receptor-B4 (EPHB4) (17.5-fold, p = 1.22 x 10-5), which cooperates with p120 RasGAP to regulate vascular development. Additional probands had damaging variants in ACVRL1, NOTCH1, ITGB1, and PTPN11. ACVRL1 variants were also identified in a multi-generational VOGM pedigree. Integrative genomic analysis defined developing endothelial cells as a likely spatio-temporal locus of VOGM pathophysiology. Mice expressing a VOGM-specific EPHB4 kinase-domain missense variant (Phe867Leu) exhibited disrupted developmental angiogenesis and impaired hierarchical development of arterial-capillary-venous networks, but only in the presence of a "second-hit" allele. These results illuminate human arterio-venous development and VOGM pathobiology and have implications for patients and their families.

Does subtotal resection ameliorate hypothalamic morbidity in pediatric craniopharyngioma? A 30-year retrospective cohort study.

OBJECTIVE: The optimal extent of resection of craniopharyngiomas to minimize the long-term risks of hypothalamic and endocrine dysfunction (obesity and panhypopituitarism) in children remains uncertain. The purpose of this study was to report long-term outcomes of pediatric patients with craniopharyngioma undergoing surgical treatment and to study rates of endocrinological and hypothalamic dysfunction in association with extent of resection. METHODS: This retrospective study was performed in a cohort of children who underwent resection for craniopharyngioma at Children's of Alabama between 1990 and 2020. The primary outcome was hypothalamic dysfunction defined as a 0.5 increase in body mass index (BMI) Z-score and as a BMI > 2 SDs with or without psychiatric disturbances. Univariable analysis was performed using ANOVA, Wilcoxon rank-sum test, Pearson's chi-square test, and Fisher's exact test as appropriate. Missing data on the primary outcome were handled via multiple imputations. Relative risks were estimated using a multivariable generalized linear model with a priori variables selected using a modified Poisson regression approach with robust error variance to estimate risk ratios. RESULTS: The cohort includes 39 patients (24 girls and 15 boys; age range 1 month-16 years) who underwent resection of craniopharyngioma at the authors' center between 1990 and 2020. The preoperative goal of treatment was cyst decompression (CD) in 5, subtotal resection (STR) in 13, and gross-total resection (GTR) in 21 patients. The median long-term follow-up after surgery was 8.11 years (average 8.21, range 0.4-24.33 years). Univariate analysis demonstrated a statistically significant increase in hypothalamic dysfunction in patients undergoing GTR when compared to those undergoing STR or CD at 1 month postoperatively (p = 0.006) and 6-11 months postoperatively (p = 0.010), but with this difference not persisting beyond 1 year. Multivariable analysis showed patients older than 10 years at time of surgery to be the most affected and at highest risk of developing significant hypothalamic dysfunction. There was no significant difference in pituitary or neurological function between the STR/CD and GTR groups at 12-24 months or at most recent follow-up. There was no significant difference in BMI Z-scores between the STR/CD and GTR groups at 6-12 months or at most recent follow-up. CONCLUSIONS: Both STR and GTR of craniopharyngioma were associated with significant endocrinological sequelae after 1 year. These potential complications should be discussed with patients and their families, and postoperative protocols should include early nutritional and endocrinological interventions with endocrinologist consultation.

Oncolytic virotherapies for pediatric tumors.

INTRODUCTION: Many pediatric patients with malignant tumors continue to suffer poor outcomes. The current standard of care includes maximum safe surgical resection followed by chemotherapy and radiation which may be associated with considerable long-term morbidity. The emergence of oncolytic virotherapy (OVT) may provide an alternative or adjuvant treatment for pediatric oncology patients. AREAS COVERED: We reviewed seven virus types that have been investigated in past or ongoing pediatric tumor clinical trials: adenovirus (AdV-tk, Celyvir, DNX-2401, VCN-01, Ad-TD-nsIL-12), herpes simplex virus (G207, HSV-1716), vaccinia (JX-594), reovirus (pelareorep), poliovirus (PVSRIPO), measles virus (MV-NIS), and Senecavirus A (SVV-001). For each virus, we discuss the mechanism of tumor-specific replication and cytotoxicity as well as key findings of preclinical and clinical studies. EXPERT OPINION: Substantial progress has been made in the past 10 years regarding the clinical use of OVT. From our review, OVT has favorable safety profiles compared to chemotherapy and radiation treatment. However, the antitumor effects of OVT remain variable depending on tumor type and viral agent used. Although the widespread adoption of OVT faces many challenges, we are optimistic that OVT will play an important role alongside standard chemotherapy and radiotherapy for the treatment of malignant pediatric solid tumors in the future.

Racial differences in the care of pediatric sagittal craniosynostosis: a single-institution cohort study affecting state Medicaid policy.

OBJECTIVE: Although research has shown the cost-effectiveness of endoscopic versus open repair of sagittal synostosis, few studies have shown how race, insurance status, and area deprivation impact care for these patients. The authors analyzed data from children evaluated for sagittal synostosis at a single institution to assess how socioeconomic factors, race, and insurance status affect the surgical treatment of this population. They hypothesized that race and indicators of disadvantage negatively impact workup and surgical timing for craniosynostosis surgery. METHODS: Medical records of patients treated for sagittal synostosis between 2010 and 2019 were reviewed. Area deprivation index (ADI) and rural-urban commuting area codes, as well as median income by zip code, were used to measure neighborhood disadvantage. Black and White patients were compared as well as patients using Medicaid versus private insurance. RESULTS: Fifty patients were prospectively included in the study. Thirty-one underwent open repair; 19 had endoscopic repair. All 8 (100%) Black patients had open repair, compared to 54.8% of White patients (p = 0.018). Black patients were more likely to use Medicaid compared to White patients (75.0% vs 28.6%, p = 0.019). White patients were younger at surgery (5.5 vs 10.0 months, p = 0.001), and Black patients had longer surgeries (147.5 minutes vs 110.0 minutes, p = 0.021). The median household income by zip code was similar for the two groups. Black patients were generally from areas of greater disadvantage compared to White patients, based on both state and national ADI scores (state: 7.5 vs 4.0, p = 0.013; national: 83.5 vs 60.0, p = 0.013). All (94.7%) but 1 patient undergoing endoscopic repair used private insurance compared to 14 (45.2%) patients in the open repair group (p = 0.001). Patients using Medicaid were from areas of greater disadvantage compared to those using private insurance by both state and national ADI scores (state: 6.0 vs 3.0, p = 0.001; national: 75.0 vs 52.0, p = 0.001). CONCLUSIONS: Because Medicaid in the geographic region of this study did not cover helmeting after endoscopic repair of sagittal synostosis, these patients usually had open repair, resulting in significant racial and socioeconomic disparities in treatment of sagittal synostosis. This research has led to a change in Alabama Medicaid policy to now cover the cost of postoperative helmeting.

What has changed in pediatric neurosurgical care in spina bifida? A 30-year UAB/Children's of Alabama observational overview.

Spina bifida (SB) remains the most serious and most common congenital anomaly of the human nervous system that is compatible with life. The open myelomeningocele on the back is perhaps the most obvious initial problem, but the collective impact of dysraphism upon the entirety of the nervous system and innervated organs is an equal or greater longitudinal threat. As such, patients with myelomeningocele (MMC) are best managed in a multi-disciplinary clinic that brings together experienced medical, nursing, and therapy teams that provide high standards of care while studying outcomes and sharing insights and experiences. Since its inception 30 years ago, the spina bifida program at UAB/Children's of Alabama has remained dedicated to providing exemplary multi-disciplinary care for affected children and their families. During this time, there has been great change in the care landscape, but many of the neurosurgical principles and primary issues have remained the same. In utero myelomeningocele closure (IUMC) has revolutionized initial care and has favorable impact on several important co-morbidities of SB including hydrocephalus, the Chiari II malformation, and the functional level of the neurologic deficit. Hydrocephalus however is not solved by IUMC, and hydrocephalus management remains at the center of neurosurgical care in SB. Ventricular shunts were long the cornerstone of treatment for hydrocephalus, but we came to assess and incorporate endoscopic third ventriculostomy with choroid plexus coagulation (ETV-CPC). Educated and nurtured by an experienced senior mentor, we dedicated ourselves to fundamental concepts but persistently evaluated our care outcomes and evolved our protocols and paradigms for improvement. Active conversations amidst networks of treasured colleagues were central to this development and growth. While hydrocephalus support and treatment of tethered spinal cord remained our principal neurosurgical charges, we evolved to embrace a holistic perspective and approach that is reflected and captured in the Lifetime Care Plan. Our team engaged actively in important workshops and guideline initiatives and was central to the development and support of the National Spina Bifida Patient Registry. We started and developed an adult SB clinic to support our patients who aged out of pediatric care. Lessons there taught us the importance of a model of transition that emphasized personal responsibility and awareness of health and the crucial role of dedicated support over time. Support for sleep, bowel health, and personal intimate cares are important contributors to overall health and care. This paper details our growth, learning, and evolution of care provision over the past 30 years.

Optimizing Surgical Performance Using Preoperative Virtual Reality Planning: A Systematic Review.

BACKGROUND: Surgery is often a complex process that requires detailed 3-dimensional anatomical knowledge and rigorous interplay between team members to attain ideal operational efficiency or "flow." Virtual Reality (VR) represents a technology by which to rehearse complex plans and communicate precise steps to a surgical team prior to entering the operating room. The objective of this study was to evaluate the use of VR for preoperative surgical team planning and interdisciplinary communication across all surgical specialties. METHODS: A systematic review of the literature was performed examining existing research on VR use for preoperative surgical team planning and interdisciplinary communication across all surgical fields in order to optimize surgical efficiency. MEDLINE, SCOPUS, CINAHL databases were searched from inception to July 31, 2022 using standardized search clauses. A qualitative data synthesis was performed with particular attention to preoperative planning, surgical efficiency optimization, and interdisciplinary collaboration/communication techniques determined a priori. Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines were followed. All included studies were appraised for their quality using the Medical Education Research Study Quality Instrument (MERSQI) tool. RESULTS: One thousand and ninety-three non-duplicated articles with abstract and full text availability were identified. Thirteen articles that examined preoperative VR-based planning techniques for optimization of surgical efficiency and/or interdisciplinary communication fulfilled inclusion and exclusion criteria. These studies had a low-to-medium methodological quality with a MERSQI mean score of 10.04 out of 18 (standard deviation 3.61). CONCLUSIONS: This review demonstrates that time spent rehearsing and visualizing patient-specific anatomical relationships in VR may improve operative efficiency and communication across multiple surgical specialties.

Genetic dysregulation of an endothelial Ras signaling network in vein of Galen malformations.

To elucidate the pathogenesis of vein of Galen malformations (VOGMs), the most common and severe congenital brain arteriovenous malformation, we performed an integrated analysis of 310 VOGM proband-family exomes and 336,326 human cerebrovasculature single-cell transcriptomes. We found the Ras suppressor p120 RasGAP ( RASA1 ) harbored a genome-wide significant burden of loss-of-function de novo variants (p=4.79×10 -7 ). Rare, damaging transmitted variants were enriched in Ephrin receptor-B4 ( EPHB4 ) (p=1.22×10 -5 ), which cooperates with p120 RasGAP to limit Ras activation. Other probands had pathogenic variants in ACVRL1 , NOTCH1 , ITGB1 , and PTPN11 . ACVRL1 variants were also identified in a multi-generational VOGM pedigree. Integrative genomics defined developing endothelial cells as a key spatio-temporal locus of VOGM pathophysiology. Mice expressing a VOGM-specific EPHB4 kinase-domain missense variant exhibited constitutive endothelial Ras/ERK/MAPK activation and impaired hierarchical development of angiogenesis-regulated arterial-capillary-venous networks, but only when carrying a "second-hit" allele. These results illuminate human arterio-venous development and VOGM pathobiology and have clinical implications.

Understanding and identifying the needs of parent caregivers of children with hydrocephalus: a qualitative study.

OBJECTIVE: Hydrocephalus is inherently unpredictable. Most parents whose child is diagnosed with hydrocephalus do not anticipate the diagnosis, nor can anyone predict if or when a child's shunt will fail and require emergency surgery. Previous research has shown that children with hydrocephalus and their caregivers experience significant posttraumatic stress symptoms secondary to the diagnosis. This study aims to understand caregiver experiences and needs, identify gaps in resources/support, and determine opportunities to improve care. METHODS: Semistructured interviews were conducted with parent caregivers of children with hydrocephalus to learn about their experiences with the hydrocephalus diagnosis, hospitalizations, surgeries, coping and support, challenges of caring for a child with hydrocephalus, and logistics for a proposed support program. De-identified interviews were audio-recorded, transcribed, and analyzed for themes. RESULTS: Thematic saturation was reached after 17 interviews. Five major themes emerged: 1) coping with the diagnosis, 2) received support, 3) hydrocephalus management, 4) implications for intervention, and 5) psychosocial stressors for caregivers. A top priority was balanced, trustworthy information delivered with compassion and updated throughout the child's life. Caregivers described a variety of coping strategies, but a majority reported a need for support in processing complex emotions and dealing with the uncertainty of their child's hydrocephalus. Most agreed that having a caregiver support network, medical professionals available for referrals and questions, and referrals to support services and therapies would facilitate feeling supported and providing the best care for their children. CONCLUSIONS: Parent caregivers are critical to the health and well-being of children with hydrocephalus, and it is essential to understand their experiences to improve care. Providing well-defined information, psychosocial support, and resources will help to equip parent caregivers to be advocates for their children and to improve both the caregiver and the child's quality of life.

The utility and post-operative evolution of head circumference in nonsyndromic single-suture craniosynostosis: a prospective study in Vietnamese children.

PURPOSE: Head circumference (HC) is an important clinical tool for following head growth in children with craniosynostosis (CS). The purpose of this study is to quantify the usefulness of HC along continuum of CS care, from diagnosis to pre- and post-operative (pre-op, post-op) follow-up in Vietnamese children. METHODS: A prospective cohort of 54 nonsyndromic single-suture CS patients undergoing open surgery from January 2015 to January 2020 was collected at Children's Hospital 2, Vietnam. HC z-score on admission was compared with World Health Organization (WHO) standards to evaluate for utility in initial diagnosis. Pre-op and post-op HC were compared to demonstrate the evolution of head growth following reconstruction. RESULTS: Nonsyndromic single-suture CS was more predominant in males (79.6%) than in females (20.4%). The mean HC z-score was - 0.38 [Formula: see text] 1.29 similar to normal WHO standards regardless of which sutural involvement. The HC z-score increased above + 1 standard deviation (SD) significantly at 3 months of follow-up (p < 0.001); however, the trajectory gradually decreased after the first year of surgery. One patient (1.8%, 1/54) demonstrated restenosis and delayed intracranial hypertension (DIH) 4 years after reconstruction. CONCLUSIONS: The HC in nonsyndromic single-suture CS children presents similarly to the values of healthy children. Additionally, HC reliably increased after reconstruction and gradually normalized over subsequent years. This indicator is consistent in Southeast Asian populations and should be used to follow all patients to assess the normal progression of post-op head growth and as a useful indicator of suspected recurrent synostosis.

Immunotherapy for Pediatric Brain and Spine Tumors: Current State and Future Directions.

BACKGROUND: Brain tumors are the most common solid tumors and the leading cause of cancer-related deaths in children. Incidence in the USA has been on the rise for the last 2 decades. While therapeutic advances in diagnosis and treatment have improved survival and quality of life in many children, prognosis remains poor and current treatments have significant long-term sequelae. SUMMARY: There is a substantial need for the development of new therapeutic approaches, and since the introduction of immunotherapy by immune checkpoint inhibitors, there has been an exponential increase in clinical trials to adopt these and other immunotherapy approaches in children with brain tumors. In this review, we summarize the current immunotherapy landscape for various pediatric brain tumor types including choroid plexus tumors, embryonal tumors (medulloblastoma, AT/RT, PNETs), ependymoma, germ cell tumors, gliomas, glioneuronal and neuronal tumors, and mesenchymal tumors. We discuss the latest clinical trials and noteworthy preclinical studies to treat these pediatric brain tumors using checkpoint inhibitors, cellular therapies (CAR-T, NK, T cell), oncolytic virotherapy, radioimmunotherapy, tumor vaccines, immunomodulators, and other targeted therapies. KEY MESSAGES: The current landscape for immunotherapy in pediatric brain tumors is still emerging, but results in certain tumors have been promising. In the age of targeted therapy, genetic tumor profiling, and many ongoing clinical trials, immunotherapy will likely become an increasingly effective tool in the neuro-oncologist armamentarium.

Outcomes of endovascular embolization for Vein of Galen malformations: An individual participant data meta-analysis.

Introduction: Understanding outcomes after Vein of Galen malformation (VOGM) embolization has been limited by small sample size in reported series and predominantly single center studies. To address these limitations, we perform an individual-participant meta-analysis (IPMA) to identify risk factors associated with all-cause mortality and clinical outcome after VOGM endovascular embolization. Methods: We performed a systematic review and IPMA of VOGM endovascular outcomes according to PRISMA guidelines. Individual patient characteristics including demographic, intra/post-operative adverse events, treatment efficacy (partial or complete occlusion), and clinical outcome were collected. Mixed-effects logistic regression with random effects modeling and Bonferroni correction was used (p ≤ 0.003 threshold for statistical significance). The primary and secondary outcomes were all-cause mortality and poor clinical outcome (moderate/severe developmental delay or permanent disabling injury), respectively. Data are expressed as (mean ± standard deviation (SD)) or (odds ratio (OR), 95% confidence interval (CI), I 2, p-value). Results: Thirty-five studies totaling 307 participants quantifying outcomes after endovascular embolization for VOGM were included. Follow up time was 42 (±57) months. Our analysis contained 42% neonates (<1 month) at first embolization, 45% infants (1 month ≤2 years), and 13% children (>2 years). Complete occlusion was reported in 48% of participants. Overall all-cause mortality was 16%. Overall, good clinical outcome was achieved in 68% of participants. First embolization as a neonate [OR = 6.93; 95% CI (1.99-24.08); I 2 < 0.01; p < 0.001] and incomplete embolization [OR = 10.87; 95% CI (1.86-63.55); I 2 < 0.01; p < 0.001] were associated with mortality. First embolization as a neonate [OR = 3.24; 95% CI (1.47-7.15); I 2 < 0.01; p < 0.001], incomplete embolization [OR = 5.26; 95% CI (2.06-13.43); I 2 < 0.01; p < 0.001], and heart failure at presentation [OR = 3.10; 95% CI (1.03-9.33); I 2 < 0.01; p = 0.002] were associated with poor clinical outcomes. Sex, angioarchitecture of lesion, embolization approach (transvenous vs. transarterial), and single or multistage embolization were not associated with mortality or clinical outcome. Conclusions: We identify incomplete VOGM embolization independently associated with mortality and poor clinical outcome. While this study provides the highest level of evidence for VOGM embolization to date, prospective multicenter studies are needed to understand the optimal treatment strategies, outcomes, and natural history after VOGM embolization.

Establishing collaborations in global neurosurgery: The role of InterSurgeon.

The global deficiency in surgical care has been highlighted in the past several years, through the publication of the Lancet Commission on Global Surgery in 2015, the passage of WHA Resolution 68.15, and concerted efforts by advocacy organizations such as the G4 Alliance.Approximately 23,300 additional neurosurgeons are estimated to be needed to address the greater than 5 million essential neurosurgical cases that are not performed annually, most in low- and middle-income countries (LMICs). However, increasing recognition of the ease and feasibility of virtual technology prompted a shift towards virtual modes of communication. InterSurgeon (https://www.intersurgeon.org/), an independent, internet-based social network platform, has allowed for formal connection between global surgery advocates who may have complementary needs and resources.This manuscript aims to: 1) characterize the current progress of InterSurgeon, 2) describe lessons learned from the creation and use of InterSurgeon, and 3) discuss future directions for InterSurgeon. Equitable, well-designed collaborations are central to progress in global neurosurgery. InterSurgeon has catalyzed collaborations within global neurosurgery across world regions and country income status. In addition to its role in facilitating traditional in person collaborations, InterSurgeon will become an increasingly important tool for connecting surgeons worldwide as virtual collaboration and augmented reality training paradigms become important components of global surgery capacity building.

Clinical advances in oncolytic virotherapy for pediatric brain tumors.

Malignant brain tumors constitute nearly one-third of cancer diagnoses in children and have recently surpassed hematologic malignancies as the most lethal neoplasm in the pediatric population. Outcomes for children with brain tumors are unacceptably poor and current standards of care-surgical resection, chemotherapy, and radiation-are associated with significant long-term morbidity. Oncolytic virotherapy has emerged as a promising immunotherapy for the treatment of brain tumors. While the majority of brain tumor clinical trials utilizing oncolytic virotherapy have been in adults, five viruses are being tested in pediatric brain tumor clinical trials: herpes simplex virus (G207), reovirus (pelareorep/Reolysin), measles virus (MV-NIS), poliovirus (PVSRIPO), and adenovirus (DNX-2401, AloCELYVIR). Herein, we review past and current pediatric immunovirotherapy brain tumor trials including the relevant preclinical and clinical research that contributed to their development. We describe mechanisms by which the viruses may overcome barriers in treating pediatric brain tumors, examine challenges associated with achieving effective, durable responses, highlight unique aspects and successes of the trials, and discuss future directions of immunovirotherapy research for the treatment of pediatric brain tumors.