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.

A qualitative analysis of patient and caregiver experiences with myelomeningocele through online discussion boards

PURPOSE

Patients and caregivers impacted by myelomeningocele (MMC) use online discussion board forums to create community and share information and concerns about this complex medical condition. We aim to identify the primary concerns expressed on these forums with the goal of understanding gaps in care that may merit investment of resources to improve care received by this population.

METHODS

Anonymous posts from online MMC discussion boards were compiled using internet search engines. Posts were then analyzed using an adaptation of the Grounded Theory Method, a three-step system involving open, axial, and selective coding of the data by two independent researchers to identify common themes.

RESULTS

Analysis of 400 posts written primarily by parents (n = 342, 85.5%) and patients (n = 45, 11.25%) yielded three overarching themes: questions surrounding quality of life, a lack of support for mothers of children with MMC, and confusion with a complex healthcare system. Many posts revealed concerns about management and well-being with MMC, including posts discussing symptoms and related conditions (n = 299, 75.75%), treatments (n = 259, 65.75%), and emotional aspects of MMC (n = 146, 36.5%). Additionally, families, especially mothers, felt a lack of support in their roles as caregivers. Finally, in 118 posts (29.5%), patients and families expressed frustration with navigating a complex healthcare system and finding specialists whose opinions they trusted.

CONCLUSIONS

MMC is a complex medical condition that impacts patients and families in unique ways. Analysis of online discussion board posts identified key themes to be addressed in order to improve the healthcare experiences of those impacted by MMC.

Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study

BACKGROUND

Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities.

METHODS

Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement.

RESULTS

Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery.

CONCLUSIONS

In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

Patient and caregiver perceptions of Chiari malformation: a qualitative analysis of online discussion boards

OBJECTIVE

Patients and their caregivers utilize online discussion board forums as a means to seek and exchange information about their or a loved one's condition. It is important for providers to be aware of such concerns and experiences. The goal of this study was to identify the primary concerns expressed on these discussion boards regarding Chiari malformation type I (CM) and to help guide clinicians in understanding patient challenges in the treatment of CM.

METHODS

The authors performed thematic analysis of anonymous online discussion board posts as identified through internet search engines. They then adopted a previously developed grounded theory method that utilizes a three-tiered coding and grouping process of posts based on commonly discovered content themes.

RESULTS

Analysis of 400 discussion board posts identified four distinct themes raised by CM patients and their caregivers: the path to diagnosis, symptoms experienced, surgical intervention, and high emotional burden. Although each individual experience was unique, the path toward a CM diagnosis was expressed as a journey involving multiple physicians, alternative diagnoses, and feelings of dismissal from providers. The most common reported symptoms included dizziness, headaches, neck and back pain, sensory issues, weakness and paresthesias of the extremities, speech issues, and general fatigue. Additionally, there was an overall sense of uncertainty from patients seeking advice regarding surgical intervention, with users expressing diverse sentiments that included both positive and negative outcomes regarding surgical treatment. Lastly, a wide range of emotions was expressed related to a CM diagnosis, including concern, worry, anxiety, depression, stress, fear, and frustration.

CONCLUSIONS

CM is a frequent imaging diagnosis identified in patients presenting with a wide range of symptoms, and as a result this leads to a diverse set of patient experiences. Analysis of CM patient and caregiver discussion boards revealed key themes that clinicians may address when counseling for CM.

Head growth in patients with myelomeningocele treated with prenatal and postnatal surgery

OBJECTIVE

The need for permanent CSF diversion is lower in patients who have undergone prenatal surgery for myelomeningocele (MMC) than in those who have undergone postnatal closure. Differences in brain development and head growth between treatment groups are not known, particularly for those who do not require surgical treatment for hydrocephalus. The objective of this study was to determine differences in head growth and to generate MMC-specific head circumference (HC) growth curves for patients who underwent either prenatal or postnatal surgery.

METHODS

The authors retrospectively identified patients from St. Louis Children's Hospital who were treated for MMC between 2016 and 2021. HC data were obtained from birth until the most recent follow-up or hydrocephalus treatment. Nonlinear least-squares regression analysis was performed to fit the data into four models: two-term power, Gompertz, West ontogenetic, and Weibull. Subsequently, the curves were assessed for their utility in predicting hydrocephalus treatment.

RESULTS

Sixty-one patients (29 females [47.5%], 25 [41%] underwent prenatal surgery, mean gestational age at birth 36.6 weeks) were included in the study. The Weibull model best fit the HC data (prenatal adjusted R2 = 0.95, postnatal adjusted R2 = 0.95), while the Gompertz model had the worst fit (prenatal adjusted R2 = 0.56, postnatal adjusted R2 = 0.39) across both cohorts. Prenatal MMC repair patients had significantly larger HC measurements than their postnatal repair counterparts. The 50th percentile of the Weibull curve was determined as a useful threshold for hydrocephalus treatment: children with HC measurements that crossed and remained above this threshold were significantly more likely to have hydrocephalus treatment regardless of time of MMC repair (prenatal relative risk [RR] 10.0 [95% CI 1.424-70.220], sensitivity 85.7% [95% CI 0.499-0.984], and specificity 82.4% [95% CI 0.600-0.948]; postnatal RR 4.750 [95% CI 1.341-16.822], sensitivity 90.5% [95% CI 0.728-0.980], and specificity 75.0% [95% CI 0.471-0.924]). The HC growth curves of the MMC patients treated prenatally were significantly larger than the WHO HC curves (p < 0.001).

CONCLUSIONS

The Weibull model was identified as the HC growth curve with the best fit for MMC patients and serves as a useful predictor of hydrocephalus treatment. For MMC patients with hydrocephalus, prenatal repair patients fit the model well but postnatal repair patients did not, potentially indicating different mechanisms of hydrocephalus development. Those treated prenatally had significantly larger HC measurements compared with both the general population and those treated postnatally. Further study is needed to understand the long-term cognitive outcomes and optimal management of clinically asymptomatic patients with large HC measurements who were treated prenatally for MMC.

Predictors and timing of hydrocephalus treatment in patients undergoing prenatal versus postnatal surgery for myelomeningocele

OBJECTIVE

Although hydrocephalus rates have decreased with intrauterine surgery for myelomeningocele (MMC), 40%-85% of children with MMC still go on to develop hydrocephalus. Prenatal ventricle size is known to be associated with later development of hydrocephalus; however, it is not known how prediction measures or timing of hydrocephalus treatment differ between pre- and postnatal surgery for MMC. The goal of this study was to determine anatomical, clinical, and radiological characteristics that are associated with the need for and timing of hydrocephalus treatment in patients with MMC.

METHODS

The authors retrospectively identified patients from Barnes Jewish Hospital or St. Louis Children's Hospital between 2016 and 2021 who were diagnosed with MMC prenatally and underwent either pre- or postnatal repair. Imaging, clinical, and demographic data were examined longitudinally between treatment groups and hydrocephalus outcomes.

RESULTS

Fifty-eight patients were included (27 females, 46.6%), with a mean gestational age at birth of 36.8 weeks. Twenty-three patients (39.7%) underwent prenatal surgery. For the overall cohort, the ventricle size at prenatal ultrasound (HR 1.175, 95% CI 1.071-1.290), frontal-occipital horn ratio (FOHR) at birth > 0.50 (HR 3.603, 95% CI 1.488-8.720), and mean rate of change in head circumference (HC) in the first 90 days after birth (> 0.10 cm/day: HR 12.973, 95% CI 4.262-39.486) were identified as predictors of hydrocephalus treatment. The factors associated with hydrocephalus in the prenatal cohort were FOHR at birth > 0.50 (HR 27.828, 95% CI 2.980-259.846) and the rate of change in HC (> 0.10 cm/day: HR 39.414, 95% CI 2.035-763.262). The factors associated with hydrocephalus in the postnatal cohort were prenatal ventricle size (HR 1.126, 95% CI 1.017-1.246) and the mean rate of change in HC (> 0.10 cm/day: HR 24.202, 95% CI 5.119-114.431). FOHR (r = -0.499, p = 0.008) and birth HC (-0.409, p = 0.028) were correlated with time to hydrocephalus across both cohorts. For patients who underwent treatment for hydrocephalus, those in the prenatal surgery group were significantly more likely to develop hydrocephalus after 3 months than those treated with postnatal surgery, although the overall rate of hydrocephalus was significantly higher in the postnatal surgery group (p = 0.018).

CONCLUSIONS

Clinical and imaging factors associated with hydrocephalus treatment differ between those receiving pre- versus postnatal MMC repair, and while the overall rate of hydrocephalus is lower, those undergoing prenatal repair are more likely to develop hydrocephalus after 3 months of age. This has implications for clinical follow-up timing for patients treated prenatally, who may live at a distance from the treatment site.

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.

Cognitive Development in Lambdoid Craniosynostosis: A Systematic Review and Meta-Analysis

OBJECTIVE

Lambdoid craniosynostosis affects approximately 1 in 33 000 live births per year, and surgical correction is often sought in order to achieve normocephaly and allow for adequate brain growth. However, the effects of lambdoid synostosis and its treatment on cognitive development are unknown.

DESIGN

Systematic review and meta-analysis.

PATIENTS, PARTICIPANTS

A systematic review of Ovid Medline, Embase, Web of Science, Scopus, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov was conducted in January 2022. Included studies assessed cognitive development of patients with nonsyndromic unilateral lambdoid craniosynostosis.

MAIN OUTCOME MEASURES

Results of developmental tests were compared to normative data or controls to generate Hedges' g for meta-analysis.

RESULTS

Nine studies met the inclusion criteria. Meta-analysis of 3 studies describing general cognition showed that cases scored significantly lower than their peers, but within 1 standard deviation (g = 0.37, 95% CI [-0.64, -0.10], P = .01). Meta-analysis of verbal and psychomotor development showed no significant differences in children with lambdoid synostosis. Studies were of fair quality and had moderate-to-high heterogeneity.

CONCLUSIONS

Patients with lambdoid craniosynostosis may score slightly below average on tests of general cognition in comparison to normal controls, but results in other domains are variable. Analyses were limited by small sample sizes. Multidisciplinary care and involvement of a child psychologist may be helpful in identifying areas of concern and providing adequate scholastic support. Further research recruiting larger cohorts will be necessary to confirm these findings and extend them to other developmental domains such as attention and executive function.

Pro-inflammatory cerebrospinal fluid profile of neonates with intraventricular hemorrhage: clinical relevance and contrast with CNS infection

BACKGROUND

Interpretation of cerebrospinal fluid (CSF) studies can be challenging in preterm infants. We hypothesized that intraventricular hemorrhage (IVH), post-hemorrhagic hydrocephalus (PHH), and infection (meningitis) promote pro-inflammatory CSF conditions reflected in CSF parameters.

METHODS

Biochemical and cytological profiles of lumbar CSF and peripheral blood samples were analyzed for 81 control, 29 IVH grade 1/2 (IVH1/2), 13 IVH grade 3/4 (IVH3/4), 15 PHH, 20 culture-confirmed bacterial meningitis (BM), and 27 viral meningitis (VM) infants at 36.5 ± 4 weeks estimated gestational age.

RESULTS

PHH infants had higher (p < 0.02) CSF total cell and red blood cell (RBC) counts compared to control, IVH1/2, BM, and VM infants. No differences in white blood cell (WBC) count were found between IVH3/4, PHH, BM, and VM infants. CSF neutrophil counts increased (p ≤ 0.03) for all groups compared to controls except IVH1/2. CSF protein levels were higher (p ≤ 0.02) and CSF glucose levels were lower (p ≤ 0.003) for PHH infants compared to all other groups. In peripheral blood, PHH infants had higher (p ≤ 0.001) WBC counts and lower (p ≤ 0.03) hemoglobin and hematocrit than all groups except for IVH3/4.

CONCLUSIONS

Similarities in CSF parameters may reflect common pathological processes in the inflammatory response and show the complexity associated with interpreting CSF profiles, especially in PHH and meningitis/ventriculitis.

A re-evaluation of the Endoscopic Third Ventriculostomy Success Score: a Hydrocephalus Clinical Research Network study

OBJECTIVE

The Hydrocephalus Clinical Research Network (HCRN) conducted a prospective study 1) to determine if a new, better-performing version of the Endoscopic Third Ventriculostomy Success Score (ETVSS) could be developed, 2) to explore the performance characteristics of the original ETVSS in a modern endoscopic third ventriculostomy (ETV) cohort, and 3) to determine if the addition of radiological variables to the ETVSS improved its predictive abilities.

METHODS

From April 2008 to August 2019, children (corrected age ≤ 17.5 years) who underwent a first-time ETV for hydrocephalus were included in a prospective multicenter HCRN study. All children had at least 6 months of clinical follow-up and were followed since the index ETV in the HCRN Core Data Registry. Children who underwent choroid plexus cauterization were excluded. Outcome (ETV success) was defined as the lack of ETV failure within 6 months of the index procedure. Kaplan-Meier curves were constructed to evaluate time-dependent variables. Multivariable binary logistic models were built to evaluate predictors of ETV success. Model performance was evaluated with Hosmer-Lemeshow and Harrell's C statistics.

RESULTS

Seven hundred sixty-one children underwent a first-time ETV. The rate of 6-month ETV success was 76%. The Hosmer-Lemeshow and Harrell's C statistics of the logistic model containing more granular age and etiology categorizations did not differ significantly from a model containing the ETVSS categories. In children ≥ 12 months of age with ETVSSs of 50 or 60, the original ETVSS underestimated success, but this analysis was limited by a small sample size. Fronto-occipital horn ratio (p = 0.37), maximum width of the third ventricle (p = 0.39), and downward concavity of the floor of the third ventricle (p = 0.63) did not predict ETV success. A possible association between the degree of prepontine adhesions on preoperative MRI and ETV success was detected, but this did not reach statistical significance.

CONCLUSIONS

This modern, multicenter study of ETV success shows that the original ETVSS continues to demonstrate good predictive ability, which was not substantially improved with a new success score. There might be an association between preoperative prepontine adhesions and ETV success, and this needs to be evaluated in a future large prospective study.

A Systematic Review of the State of Neurosurgical Disparities Research: Past, Present, and Future

BACKGROUND

The social determinants of health, which influence healthcare access, patient outcomes, and population-level burden of disease, contribute to health disparities experienced by marginalized patient populations. In the present study, we sought to evaluate the landscape of health disparities research within neurosurgery.

METHODS

Embase, Ovid-MEDLINE, Scopus, Web of Science, Cochrane Library, and ProQuest Dissertations databases were queried for original research on health disparities regarding access to, outcomes of, and/or postoperative management after neurosurgical procedures in the United States.

RESULTS

Of 883 studies screened, 196 were included, of which 144 had a neurosurgery-affiliated author. We found a significant increase in the number of neurosurgical disparities reports beginning in 2010, with only 10 studies reported before 2010. Of the included studies, 3.1% used prospective methods and 63.8% used data from national registries. The disparities analyzed were racial/ethnic (79.6%), economic/socioeconomic (53.6%), gender (18.9%), and disabled populations (0.5%), with 40.1% analyzing multiple or intersecting disparities. Of the included reports, 96.9% were in phase 1 (detecting phase of disparities research), with a few studies in phase 2 (understanding phase), and none in phase 3 (reducing phase). The spine was the most prevalent subspecialty evaluated (34.2%), followed by neuro-oncology (19.9%), cerebrovascular (16.3%), pediatrics (10.7%), functional (9.2%), general neurosurgery (5.1%), and trauma (4.1%). Senior authors with a neurosurgical affiliation accounted for 79.2% of the reports, 93% of whom were academically affiliated.

CONCLUSIONS

Although a recent increase has occurred in neurosurgical disparities research within the past decade, most studies were limited to the detection of disparities without understanding or evaluating any interventions for a reduction in disparities. Future research in neurosurgical disparities should incorporate the latter 2 factors to reduce disparities and improve outcomes for all patients.

Iron homeostasis and post-hemorrhagic hydrocephalus: a review

Iron physiology is regulated by a complex interplay of extracellular transport systems, coordinated transcriptional responses, and iron efflux mechanisms. Dysregulation of iron metabolism can result in defects in myelination, neurotransmitter synthesis, and neuronal maturation. In neonates, germinal matrix-intraventricular hemorrhage (GMH-IVH) causes iron overload as a result of blood breakdown in the ventricles and brain parenchyma which can lead to post-hemorrhagic hydrocephalus (PHH). However, the precise mechanisms by which GMH-IVH results in PHH remain elusive. Understanding the molecular determinants of iron homeostasis in the developing brain may lead to improved therapies. This manuscript reviews the various roles iron has in brain development, characterizes our understanding of iron transport in the developing brain, and describes potential mechanisms by which iron overload may cause PHH and brain injury. We also review novel preclinical treatments for IVH that specifically target iron. Understanding iron handling within the brain and central nervous system may provide a basis for preventative, targeted treatments for iron-mediated pathogenesis of GMH-IVH and PHH.

Helmet Therapy for the Management of Deformational Plagiocephaly in Pediatric Patients with Shunted Hydrocephalus

OBJECTIVE

To evaluate the safety and efficacy of helmet therapy for deformational plagiocephaly in patients with shunted hydrocephalus.

DESIGN

Retrospective chart review.

SETTING

Institutional, tertiary-care hospital.

PATIENTS

All patients at St. Louis Children's Hospital between 2014 and 2021 with shunted hydrocephalus who underwent helmet therapy for deformational plagiocephaly.

INTERVENTIONS

Helmet therapy.

MAIN OUTCOME MEASURES

Cranial vault asymmetry (CVA), cranial vault asymmetry index (CVAI), and cephalic index (CI) were measured before and after completion of helmet therapy.

RESULTS

There were 37 patients with shunted hydrocephalus and documented deformational plagiocephaly. Twelve were managed with helmet therapy. Average age at helmeting initiation and time between shunt placement and helmeting initiation was 5.8 and 4.6 months, respectively. Average CVA, CVAI, and CI at helmeting initiation and termination was 11.6, 7.98, and 85.2, and 6.95, 4.49, and 83.7, respectively. Average duration of helmeting was 3.7 months. CVA and CVAI were significantly lower after helmeting (P = .0028 and .0021) and 11/12 patients had overall improvement in plagiocephaly.

CONCLUSIONS

Helmet therapy appears to be a safe and efficacious management strategy for deformational plagiocephaly in patients with shunted hydrocephalus. Despite the occasional need for additional fittings and surveillance beyond the normal schedule, in all cases appropriately fitting helmets were achieved and no major adverse events occurred. This cohort represents a proof of principle for the safety and efficacy of helmet therapy in patients with shunted hydrocephalus. Further work in larger prospective cohorts is needed to confirm these initial findings.

Postnatal meningeal CSF transport is primarily mediated by the arachnoid and pia maters and is not altered after intraventricular hemorrhage-posthemorrhagic hydrocephalus

BACKGROUND

CSF has long been accepted to circulate throughout the subarachnoid space, which lies between the arachnoid and pia maters of the meninges. How the CSF interacts with the cellular components of the developing postnatal meninges including the dura, arachnoid, and pia of both the meninges at the surface of the brain and the intracranial meninges, prior to its eventual efflux from the cranium and spine, is less understood. Here, we characterize small and large CSF solute distribution patterns along the intracranial and surface meninges in neonatal rodents and compare our findings to meningeal CSF solute distribution in a rodent model of intraventricular hemorrhage-posthemorrhagic hydrocephalus. We also examine CSF solute interactions with the tela choroidea and its pial invaginations into the choroid plexuses of the lateral, third, and fourth ventricles.

METHODS

1.9-nm gold nanoparticles, 15-nm gold nanoparticles, or 3 kDa Red Dextran Tetramethylrhodamine constituted in aCSF were infused into the right lateral ventricle of P7 rats to track CSF circulation. 10 min post-1.9-nm gold nanoparticle and Red Dextran Tetramethylrhodamine injection and 4 h post-15-nm gold nanoparticle injection, animals were sacrificed and brains harvested for histologic analysis to identify CSF tracer localization in the cranial and spine meninges and choroid plexus. Spinal dura and leptomeninges (arachnoid and pia) wholemounts were also evaluated.

RESULTS

There was significantly less CSF tracer distribution in the dura compared to the arachnoid and pia maters in neonatal rodents. Both small and large CSF tracers were transported intracranially to the arachnoid and pia mater of the perimesencephalic cisterns and tela choroidea, but not the falx cerebri. CSF tracers followed a similar distribution pattern in the spinal meninges. In the choroid plexus, there was large CSF tracer distribution in the apical surface of epithelial cells, and small CSF tracer along the basolateral surface. There were no significant differences in tracer intensity in the intracranial meninges of control vs. intraventricular hemorrhage-posthemorrhagic hydrocephalus (PHH) rodents, indicating preserved meningeal transport in the setting of PHH.

CONCLUSIONS

Differential CSF tracer handling by the meninges suggests that there are distinct roles for CSF handling between the arachnoid-pia and dura maters in the developing brain. Similarly, differences in apical vs. luminal choroid plexus CSF handling may provide insight into particle-size dependent CSF transport at the CSF-choroid plexus border.

Medical student specialty decision-making and perceptions of neurosurgery. Part 1: Role of gender

OBJECTIVE

Although women account for 50% of medical school graduates, less than 30% of neurosurgery residency applicants and less than 10% of neurosurgeons are female. In order to diversify the field of neurosurgery and recruit more women, it is necessary to understand why there is a disproportionately low entry rate into neurosurgery by female medical students. Factors contributing to specialty decision-making and perceptions of neurosurgery among medical students and residents, specifically differences by gender, have not been studied. The authors aimed to investigate these differences using quantitative and qualitative methods.

METHODS

A Qualtrics survey was administered at the authors' institution to all medical students and resident physicians to assess factors influencing medical specialty decision-making and perceptions of neurosurgery. Likert scale responses converted to numerical values on a 5-point scale were analyzed with the Mann-Whitney U-test. The chi-square test was performed on binary responses. Semistructured interviews were conducted in a subset of survey respondents and were analyzed by using the grounded theory method.

RESULTS

Of the 272 survey respondents, 48.2% were medical students and 61.0% were female. When making specialty decisions, female medical students considered maternity/paternity leave more (p = 0.028) than their male counterparts. Female medical students were more hesitant toward neurosurgery due to maternity/paternity needs (p = 0.031) and the technical skill required (p = 0.020) than male medical students. Across both genders, the majority of medical students were hesitant toward neurosurgery due to opportunities for work/life integration (93%), length of training (88%), malignancy of the field (76%), and perceived happiness of the people in the field (76%). Female residents indicated they were more likely than male residents to consider the perceived happiness of the people in the field (p = 0.003), shadowing experiences (p = 0.019), and elective rotations (p = 0.004) when making specialty decisions. Two major themes emerged from the semistructured interviews: 1) maternity needs were more of a concern for women and 2) length of training was a concern for many individuals.

CONCLUSIONS

Compared with their male counterparts, female students and residents consider different factors and experiences when choosing a medical specialty and have different perceptions of neurosurgery. Exposure to and education within neurosurgery, specifically maternity needs, may help address hesitancy in pursuing a neurosurgical career among female medical students. However, cultural and structural factors may need to be addressed within neurosurgery in order to ultimately increase representation of women.

Medical student specialty decision-making and perceptions of neurosurgery. Part 2: Role of race/ethnicity

OBJECTIVE

Although individuals underrepresented in medicine (URM) make up 33% of the United States population, only 12.6% of medical school graduates identify as URM; the same percentage of URM students comprises neurosurgery residency applicants. More information is needed to understand how URM students are making specialty decisions and their perceptions of neurosurgery. The authors aimed to evaluate the differences between URM and non-URM medical students and residents in terms of the factors that contribute to specialty decision-making and perceptions of neurosurgery.

METHODS

A survey was administered to all medical students and resident physicians at a single Midwestern institution to assess factors influencing medical student specialty decision-making and perceptions of neurosurgery. Likert scale responses converted to numerical values on a 5-point scale (strongly agree was the high score of 5) were analyzed with the Mann-Whitney U-test. The chi-square test was performed on the binary responses to examine associations between categorical variables. Semistructured interviews were conducted and analyzed using the grounded theory method.

RESULTS

Of 272 respondents, 49.2% were medical students, 51.8% were residents, and 11.0% identified as URM. URM medical students considered research opportunities more than non-URM medical students in specialty decision-making (p = 0.023). When specialty decision-making factors were assessed, URM residents less strongly considered the technical skill required (p = 0.023), their perceived fit in the field (p < 0.001), and seeing people like them in the field (p = 0.010) than their non-URM counterparts when making specialty decisions. Within both medical student and resident respondent cohorts, the authors found no significant differences between URM and non-URM respondents in terms of their specialty decision-making being affected by medical school experiences such as shadowing, elective rotations, family exposure, or having a mentor in the field. URM residents were more concerned about the opportunity to work on health equity issues in neurosurgery than non-URM residents (p = 0.005). The predominant theme that emerged from interviews was the need for more intentional efforts to recruit and retain URM individuals in medicine and specifically neurosurgery.

CONCLUSIONS

URM students may make specialty decisions differently than non-URM students. URM students were more hesitant toward neurosurgery due to their perceived lack of opportunity for health equity work in neurosurgery. These findings further inform optimization of both new and existing initiatives to improve URM student recruitment and retention in neurosurgery.

Deferoxamine Prevents Neonatal Posthemorrhagic Hydrocephalus Through Choroid Plexus-Mediated Iron Clearance

Posthemorrhagic hydrocephalus occurs in up to 30% of infants with high-grade intraventricular hemorrhage and is associated with the worst neurocognitive outcomes in preterm infants. The mechanisms of posthemorrhagic hydrocephalus after intraventricular hemorrhage are unknown; however, CSF levels of iron metabolic pathway proteins including hemoglobin have been implicated in its pathogenesis. Here, we develop an animal model of intraventricular hemorrhage using intraventricular injection of hemoglobin at post-natal day 4 that results in acute and chronic hydrocephalus, pathologic choroid plexus iron accumulation, and subsequent choroid plexus injury at post-natal days 5, 7, and 15. This model also results in increased expression of aquaporin-1, Na+/K+/Cl- cotransporter 1, and Na+/K+/ATPase on the apical surface of the choroid plexus 24 h post-intraventricular hemorrhage. We use this model to evaluate a clinically relevant treatment strategy for the prevention of neurological sequelae after intraventricular hemorrhage using intraventricular administration of the iron chelator deferoxamine at the time of hemorrhage. Deferoxamine treatment prevented posthemorrhagic hydrocephalus for up to 11 days after intraventricular hemorrhage and prevented the development of sensorimotor gating deficits. In addition, deferoxamine treatment facilitated acute iron clearance through the choroid plexus and subsequently reduced choroid plexus iron levels at 24 h with reversal of hemoglobin-induced aquaporin-1 upregulation on the apical surface of the choroid plexus. Intraventricular administration of deferoxamine at the time of intraventricular hemorrhage may be a clinically relevant treatment strategy for preventing posthemorrhagic hydrocephalus and likely acts through promoting iron clearance through the choroid plexus to prevent hemoglobin-induced injury.

Impact of neighborhood deprivation and social vulnerability on long-term outcomes and desire for revision in patients with craniosynostosis

OBJECTIVE

The authors utilized the area deprivation index (ADI), a validated composite measure of socioeconomic disadvantage, and the social vulnerability index (SVI) to examine whether differences in neighborhood deprivation impact interventions and outcomes among patients with craniosynostosis.

METHODS

Patients who underwent craniosynostosis repair between 2012 and 2017 were included. The authors collected data about demographic characteristics, comorbidities, follow-up visits, interventions, complications, desire for revision, and speech, developmental, and behavioral outcomes. National percentiles for ADI and SVI were determined using zip and Federal Information Processing Standard (FIPS) codes. ADI and SVI were analyzed by tertile. Firth logistic regressions and Spearman correlations were used to assess associations between ADI/SVI tertile and outcomes/interventions that differed on univariate analysis. Subgroup analysis was performed to examine these associations in patients with nonsyndromic craniosynostosis. Differences in length of follow-up among the nonsyndromic patients in the different deprivation groups were assessed with multivariate Cox regressions.

RESULTS

In total, 195 patients were included, with 37% of patients in the most disadvantaged ADI tertile and 20% of patients in the most vulnerable SVI tertile. Patients in more disadvantaged ADI tertiles were less likely to have physician-reported desire (OR 0.17, 95% CI 0.04-0.61, p < 0.01) or parent-reported desire (OR 0.16, 95% CI 0.04-0.52, p < 0.01) for revision, independent of sex and insurance status. In the nonsyndromic subgroup, inclusion in a more disadvantaged ADI tertile was associated with increased odds of speech/language concerns (OR 4.42, 95% CI 1.41-22.62, p < 0.01). There were no differences in interventions received or outcomes among SVI tertiles (p ≥ 0.24). Neither ADI nor SVI tertile was associated with risk of loss to follow-up among nonsyndromic patients (p ≥ 0.38).

CONCLUSIONS

Patients from the most disadvantaged neighborhoods may be at risk for poor speech outcomes and different standards of assessment for revision. Neighborhood measures of disadvantage represent a valuable tool to improve patient-centered care by allowing for modification of treatment protocols to meet the unique needs of patients and their families.

Meningeal CSF transport is primarily mediated by the arachnoid and pia maters during development

Background

The recent characterization of the glymphatic system and meningeal lymphatics has re-emphasized the role of the meninges in facilitating CSF transport and clearance. Here, we characterize small and large CSF solute distribution patterns along the intracranial and surface meninges in neonatal rodents and compare our findings to a rodent model of intraventricular hemorrhage-posthemorrhagic hydrocephalus. We also examine CSF interactions with the tela choroidea and its pial invaginations into the choroid plexuses of the lateral, third, and fourth ventricles.

Methods

1.9-nm gold nanoparticles, 15-nm gold nanoparticles, or 3 kDa Red Dextran Tetramethylrhodamine constituted in aCSF were infused into the right lateral ventricle of P7 rats to track CSF circulation. 10 minutes post-1.9-nm gold nanoparticle and Red Dextran Tetramethylrhodamine injection and 4 hours post-15-nm gold nanoparticle injection, animals were sacrificed and brains harvested for histologic analysis to identify CSF tracer localization in the cranial and spine meninges and choroid plexus. Spinal dura and leptomeninges (arachnoid and pia) wholemounts were also performed.

Results

There was significantly less CSF tracer distribution in the dura compared to the arachnoid and pia maters in neonatal rodents. Both small and large CSF tracers were transported intracranially to the arachnoid and pia mater of the perimesencephalic cisterns and tela choroidea, but not the dura mater of the falx cerebri. CSF tracers followed a similar distribution pattern in the spinal meninges. In the choroid plexus, there was large CSF tracer distribution in the apical surface of epithelial cells, and small CSF tracer along the basolateral surface. There were no significant differences in tracer intensity in the intracranial meninges of control vs. intraventricular hemorrhage-posthemorrhagic hydrocephalus (PHH) rodents, indicating preserved meningeal transport in the setting of PHH.

Conclusions

Differential CSF tracer handling by the leptomeninges suggests that there are distinct roles for CSF handling between the arachnoid-pia and dura maters in the developing brain. Similarly, differences in apical vs. luminal choroid plexus CSF handling may provide insight into particle-size dependent CSF transport at the CSF-choroid plexus border.

Cognition and Brain System Segregation in Pediatric Brain Tumor Patients Treated with Proton Therapy

Purpose

Pediatric brain tumor patients often experience significant cognitive sequelae. Resting-state functional MRI (rsfMRI) provides a measure of brain network organization, and we hypothesize that pediatric brain tumor patients treated with proton therapy will demonstrate abnormal brain network architecture related to cognitive outcome and radiation dosimetry.

Participants and Methods

Pediatric brain tumor patients treated with proton therapy were enrolled on a prospective study of cognitive assessment using the NIH Toolbox Cognitive Domain. rsfMRI was obtained in participants able to complete unsedated MRI. Brain system segregation (BSS), a measure of brain network architecture, was calculated for the whole brain, the high-level cognition association systems, and the sensory-motor systems.

Results

Twenty-six participants were enrolled in the study for cognitive assessment, and 18 completed rsfMRI. There were baseline cognitive deficits in attention and inhibition and processing speed prior to radiation with worsening performance over time in multiple domains. Average BSS across the whole brain was significantly decreased in participants compared with healthy controls (1.089 and 1.101, respectively; P = 0.001). Average segregation of association systems was significantly lower in participants than in controls (P < 0.001) while there was no difference in the sensory motor networks (P = 0.70). Right hippocampus dose was associated with worse attention and inhibition (P < 0.05) and decreased segregation in the dorsal attention network (P < 0.05).

Conclusion

Higher mean dose to the right hippocampus correlated with worse dorsal attention network segregation and worse attention and inhibition cognitive performance. Patients demonstrated alterations in brain network organization of association systems measured with rsfMRI; however, somatosensory system segregation was no different from healthy children. Further work with preradiation rsfMRI is needed to assess the effects of surgery and presence of a tumor on brain network architecture.

Family Experiences with Diagnosis of Craniosynostosis: Thematic Analysis of Online Discussion Boards

OBJECTIVE

Apply thematic analysis of online discussion boards to characterize families' experiences and concerns regarding craniosynostosis diagnoses to aid physicians in tailoring care to families.

DESIGN

Grounded theory-based qualitative analysis.

SETTING

Discussion boards related to craniosynostosis identified via Google and Yahoo.

PATIENTS/PARTICIPANTS

Posts about craniosynostosis between 2017-2022.

INTERVENTIONS

Thematic analysis was performed using three rounds of coding. Post features including author type and use of technical language were examined.

MAIN OUTCOME MEASURE

Overarching themes emerging from analysis of posts, with forums analyzed until sufficient thematic repetition was observed.

RESULTS

366 posts from 4 websites by 290 unique users were included. Parents of patients with craniosynostosis wrote 59% of posts while patients wrote 4%. Five selective codes were identified: 1) Building Community, 2) Diagnosis/Evaluation, 3) Treatment, 4) Outcomes, and 5) Emotional Concerns. Building Community was the most assigned code (85% of posts). 71% of parents' posts expressing emotional concerns expressed negative emotions, commonly regarding anxiety about diagnosis (71%), frustration about doctors' responses (21%), or negative reactions to online search results (17%). 88% of patients' posts expressed positive emotions, discussing positive long-term outcomes. Concerns that may guide physicians included anxiety about delayed diagnosis, difficulty distinguishing postpartum head shape changes from craniosynostosis, and difficulty finding a care team.

CONCLUSIONS

Online discussion boards allow families of patients with craniosynostosis to share experiences and find community. Improving communication between surgeons, pediatricians, and families about timing of evaluation and revising online information about this condition may ameliorate some anxiety associated with this diagnosis.

The effect of Dnaaf5 gene dosage on primary ciliary dyskinesia phenotypes

DNAAF5 is a dynein motor assembly factor associated with the autosomal heterogenic recessive condition of motile cilia, primary ciliary dyskinesia (PCD). The effects of allele heterozygosity on motile cilia function are unknown. We used CRISPR-Cas9 genome editing in mice to recreate a human missense variant identified in patients with mild PCD and a second, frameshift-null deletion in Dnaaf5. Litters with Dnaaf5 heteroallelic variants showed distinct missense and null gene dosage effects. Homozygosity for the null Dnaaf5 alleles was embryonic lethal. Compound heterozygous animals with the missense and null alleles showed severe disease manifesting as hydrocephalus and early lethality. However, animals homozygous for the missense mutation had improved survival, with partially preserved cilia function and motor assembly observed by ultrastructure analysis. Notably, the same variant alleles exhibited divergent cilia function across different multiciliated tissues. Proteomic analysis of isolated airway cilia from mutant mice revealed reduction in some axonemal regulatory and structural proteins not previously reported in DNAAF5 variants. Transcriptional analysis of mouse and human mutant cells showed increased expression of genes coding for axonemal proteins. These findings suggest allele-specific and tissue-specific molecular requirements for cilia motor assembly that may affect disease phenotypes and clinical trajectory in motile ciliopathies.

Building consensus for the medical management of children with moderate and severe acute spinal cord injury: a modified Delphi study

OBJECTIVE

The focus of this modified Delphi study was to investigate and build consensus regarding the medical management of children with moderate and severe acute spinal cord injury (SCI) during their initial inpatient hospitalization. This impetus for the study was based on the AANS/CNS guidelines for pediatric SCI published in 2013, which indicated that there was no consensus provided in the literature describing the medical management of pediatric patients with SCIs.

METHODS

An international, multidisciplinary group of 19 physicians, including pediatric neurosurgeons, orthopedic surgeons, and intensivists, were asked to participate. The authors chose to include both complete and incomplete injuries with traumatic as well as iatrogenic etiologies (e.g., spinal deformity surgery, spinal traction, intradural spinal surgery, etc.) due to the overall low incidence of pediatric SCI, potentially similar pathophysiology, and scarce literature exploring whether different etiologies of SCI should be managed differently. An initial survey of current practices was administered, and based on the responses, a follow-up survey of potential consensus statements was distributed. Consensus was defined as ≥ 80% of participants reaching agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). A final meeting was held virtually to generate final consensus statements.

RESULTS

Following the final Delphi round, 35 statements reached consensus after modification and consolidation of previous statements. Statements were categorized into the following eight sections: inpatient care unit, spinal immobilization, pharmacological management, cardiopulmonary management, venous thromboembolism prophylaxis, genitourinary management, gastrointestinal/nutritional management, and pressure ulcer prophylaxis. All participants stated that they would be willing or somewhat willing to change their practices based on consensus guidelines.

CONCLUSIONS

General management strategies were similar for both iatrogenic (e.g., spinal deformity, traction, etc.) and traumatic SCIs. Steroids were recommended only for injury after intradural surgery, not after acute traumatic or iatrogenic extradural surgery. Consensus was reached that mean arterial pressure ranges are preferred for blood pressure targets following SCI, with goals between 80 and 90 mm Hg for children at least 6 years of age. Further multicenter study of steroid use following acute neuromonitoring changes was recommended.

Gold nanoparticle-enhanced X-ray microtomography of the rodent reveals region-specific cerebrospinal fluid circulation in the brain

Cerebrospinal fluid (CSF) is essential for the development and function of the central nervous system (CNS). However, the brain and its interstitium have largely been thought of as a single entity through which CSF circulates, and it is not known whether specific cell populations within the CNS preferentially interact with the CSF. Here, we develop a technique for CSF tracking, gold nanoparticle-enhanced X-ray microtomography, to achieve micrometer-scale resolution visualization of CSF circulation patterns during development. Using this method and subsequent histological analysis in rodents, we identify previously uncharacterized CSF pathways from the subarachnoid space (particularly the basal cisterns) that mediate CSF-parenchymal interactions involving 24 functional-anatomic cell groupings in the brain and spinal cord. CSF distribution to these areas is largely restricted to early development and is altered in posthemorrhagic hydrocephalus. Our study also presents particle size-dependent CSF circulation patterns through the CNS including interaction between neurons and small CSF tracers, but not large CSF tracers. These findings have implications for understanding the biological basis of normal brain development and the pathogenesis of a broad range of disease states, including hydrocephalus.

The effect of Dnaaf5 gene dosage on primary ciliary dyskinesia phenotypes

DNAAF5 is a dynein motor assembly factor associated with the autosomal heterogenic recessive condition of motile cilia, primary ciliary dyskinesia (PCD). The effects of allele heterozygosity on motile cilia function are unknown. We used CRISPR-Cas9 genome editing in mice to recreate a human missense variant identified in patients with mild PCD and a second, frameshift null deletion in Dnaaf5 . Litters with Dnaaf5 heteroallelic variants showed distinct missense and null gene dosage effects. Homozygosity for the null Dnaaf5 alleles was embryonic lethal. Compound heterozygous animals with the missense and null alleles showed severe disease manifesting as hydrocephalus and early lethality. However, animals homozygous for the missense mutation had improved survival, with partial preserved cilia function and motor assembly observed by ultrastructure analysis. Notably, the same variant alleles exhibited divergent cilia function across different multiciliated tissues. Proteomic analysis of isolated airway cilia from mutant mice revealed reduction in some axonemal regulatory and structural proteins not previously reported in DNAAF5 variants. While transcriptional analysis of mouse and human mutant cells showed increased expression of genes coding for axonemal proteins. Together, these findings suggest allele-specific and tissue-specific molecular requirements for cilia motor assembly that may affect disease phenotypes and clinical trajectory in motile ciliopathies.

Brief Summary

A mouse model of human DNAAF5 primary ciliary dyskinesia variants reveals gene dosage effects of mutant alleles and tissue-specific molecular requirements for cilia motor assembly.

Developing consensus for the management of pediatric cervical spine disorders and stabilization: a modified Delphi study

OBJECTIVE

Cervical spine disorders in children are relatively uncommon; therefore, paradigms for surgical and nonsurgical clinical management are not well established. The purpose of this study was to bring together an international, multidisciplinary group of pediatric cervical spine experts to build consensus via a modified Delphi approach regarding the clinical management of children with cervical spine disorders and those undergoing cervical spine stabilization surgery.

METHODS

A modified Delphi method was used to identify consensus statements for the management of children with cervical spine disorders requiring stabilization. A survey of current practices, supplemented by a literature review, was electronically distributed to 17 neurosurgeons and orthopedic surgeons experienced with the clinical management of pediatric cervical spine disorders. Subsequently, 52 summary statements were formulated and distributed to the group. Statements that reached near consensus or that were of particular interest were then discussed during an in-person meeting to attain further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree).

RESULTS

Forty-five consensus-driven statements were identified, with all participants willing to incorporate them into their practice. For children with cervical spine disorders and/or stabilization, consensus statements were divided into the following categories: A) preoperative planning (12 statements); B) radiographic thresholds of instability (4); C) intraoperative/perioperative management (15); D) postoperative care (11); and E) nonoperative management (3). Several important statements reaching consensus included the following recommendations: 1) to obtain pre-positioning baseline signals with intraoperative neuromonitoring; 2) to use rigid instrumentation when technically feasible; 3) to provide postoperative external immobilization for 6-12 weeks with a rigid cervical collar rather than halo vest immobilization; and 4) to continue clinical postoperative follow-up at least until anatomical cervical spine maturity was reached. In addition, preoperative radiographic thresholds for instability that reached consensus included the following: 1) translational motion ≥ 5 mm at C1-2 (excluding patients with Down syndrome) or ≥ 4 mm in the subaxial spine; 2) dynamic angulation in the subaxial spine ≥ 10°; and 3) abnormal motion and T2 signal change on MRI seen at the same level.

CONCLUSIONS

In this study, the authors have demonstrated that a multidisciplinary, international group of pediatric cervical spine experts was able to reach consensus on 45 statements regarding the management of pediatric cervical spine disorders and stabilization. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

Neurodevelopment in unilateral coronal craniosynostosis: a systematic review and meta-analysis

OBJECTIVE

The current literature on unilateral coronal craniosynostosis is replete with repair techniques and surgical outcomes; however, information regarding neurodevelopment remains unclear. Therefore, the aim of this systematic review and meta-analysis was to comprehensively assess the neurodevelopmental outcomes of patients with unicoronal craniosynostosis compared with their healthy peers or normative data.

METHODS

A systematic review of the Ovid MEDLINE, Embase, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov databases from database inception to January 19, 2022, was performed. Included studies assessed neurodevelopment of patients with unicoronal craniosynostosis. Two independent reviewers selected studies and extracted data based on a priori inclusion and exclusion criteria. Results of developmental tests were compared with normative data or controls to generate Hedges' g statistics for meta-analysis. The quality of included studies was evaluated using the National Institutes of Health Assessment Tool.

RESULTS

A total of 19 studies were included and analyzed, with an overall fair reporting quality. A meta-analysis of 325 postoperative patients demonstrated that scores of general neurodevelopment were below average but within one standard deviation of the norm (Hedges' g = -0.68 [95% CI -0.90 to -0.45], p < 0.001). Similarly, postoperative patients exhibited lower scores in verbal, psychomotor, and mathematic outcome assessments.

CONCLUSIONS

This systematic review and meta-analysis found that patients with unicoronal craniosynostosis had poorer neurodevelopment, although scores generally remained within the normal range. These data may guide implementation of regular neurocognitive assessments and early learning support of patients with unicoronal craniosynostosis.

Modeling Neonatal Intraventricular Hemorrhage through Intraventricular Injection of Hemoglobin

Neonatal intraventricular hemorrhage (IVH) is a common consequence of premature birth and leads to brain injury, posthemorrhagic hydrocephalus (PHH), and lifelong neurological deficits. While PHH can be treated by temporary and permanent cerebrospinal fluid (CSF) diversion procedures (ventricular reservoir and ventriculoperitoneal shunt, respectively), there are no pharmacological strategies to prevent or treat IVH-induced brain injury and hydrocephalus. Animal models are needed to better understand the pathophysiology of IVH and test pharmacological treatments. While there are existing models of neonatal IVH, those that reliably result in hydrocephalus are often limited by the necessity for large-volume injections, which may complicate modeling of the pathology or introduce variability in the clinical phenotype observed. Recent clinical studies have implicated hemoglobin and ferritin in causing ventricular enlargement after IVH. Here, we develop a straightforward animal model that mimics the clinical phenotype of PHH utilizing small-volume intraventricular injections of the blood breakdown product hemoglobin. In addition to reliably inducing ventricular enlargement and hydrocephalus, this model results in white matter injury, inflammation, and immune cell infiltration in periventricular and white matter regions. This paper describes this clinically relevant, simple method for modeling IVH-PHH in neonatal rats using intraventricular injection and presents methods for quantifying ventricle size post injection.

Etiology- and region-specific characteristics of transependymal cerebrospinal fluid flow

OBJECTIVE

Transependymal flow (TEF) of CSF, often delineated as T2-weighted hyperintensity adjacent to the lateral ventricles on MRI, is a known imaging finding, usually in the setting of CSF flow disturbances. Specific radiological features of TEF and their relationships with clinical markers of hydrocephalus and underlying disease pathology are not known. Here, the authors describe the radiological features and clinical associations of TEF with implications for CSF circulation in the setting of intracranial pathology.

METHODS

After obtaining IRB review and approval, the authors reviewed the radiological records of all patients who underwent intracranial imaging with CT or MRI at St. Louis Children's Hospital, St. Louis, Missouri, between 2008 and 2019 to identify individuals with TEF. Then, under direct review of imaging, TEF pattern, degree, and location and underlying pathology and other radiological and clinical features pertaining to CSF circulation and CSF disturbances were noted.

RESULTS

TEF of CSF was identified in 219 patients and was most prevalent in the setting of neoplasms (72%). In 69% of the overall cohort, TEF was seen adjacent to the anterior aspect of the frontal horns and the posterior aspect of the occipital horns of the lateral ventricles, and nearly half of these patients also had TEF dorsal to the third ventricle near the splenium of the corpus callosum. This pattern was independently associated with posterior fossa medulloblastoma when compared with pilocytic astrocytoma (OR 4.75, 95% CI 1.43-18.53, p = 0.0157). Patients with congenital or neonatal-onset hydrocephalus accounted for 13% of patients and were more likely to have TEF circumferentially around the ventricles without the fronto-occipital distribution. Patients who ultimately required permanent CSF diversion surgery were more likely to have the circumferential TEF pattern, a smaller degree of TEF, and a lack of papilledema at the time of CSF diversion surgery.

CONCLUSIONS

CSF transmigration across the ependyma is usually restricted to specific periventricular regions and is etiology specific. Certain radiological TEF characteristics are associated with tumor pathology and may reflect impaired or preserved ependymal fluid handling and global CSF circulation. These findings have implications for TEF as a disease-specific marker and in understanding CSF handling within the brain.

Elevated cerebrospinal fluid iron and ferritin associated with early severe ventriculomegaly in preterm posthemorrhagic hydrocephalus

OBJECTIVE

Posthemorrhagic hydrocephalus (PHH) following preterm intraventricular hemorrhage (IVH) is among the most severe sequelae of extreme prematurity and a significant contributor to preterm morbidity and mortality. The authors have previously shown hemoglobin and ferritin to be elevated in the lumbar puncture cerebrospinal fluid (CSF) of neonates with PHH. Herein, they evaluated CSF from serial ventricular taps to determine whether neonates with PHH following severe initial ventriculomegaly had higher initial levels and prolonged clearance of CSF hemoglobin and hemoglobin degradation products compared to those in neonates with PHH following moderate initial ventriculomegaly.

METHODS

In this observational cohort study, CSF samples were obtained from serial ventricular taps in premature neonates with severe IVH and subsequent PHH. CSF hemoglobin, ferritin, total iron, total bilirubin, and total protein were quantified using ELISA. Ventriculomegaly on cranial imaging was assessed using the frontal occipital horn ratio (FOHR) and was categorized as severe (FOHR > 0.6) or moderate (FOHR ≤ 0.6).

RESULTS

Ventricular tap CSF hemoglobin (mean) and ferritin (initial and mean) were higher in neonates with severe versus moderate initial ventriculomegaly. CSF hemoglobin, ferritin, total iron, total bilirubin, and total protein decreased in a nonlinear fashion over the weeks following severe IVH. Significantly higher levels of CSF ferritin and total iron were observed in the early weeks following IVH in neonates with severe initial ventriculomegaly than in those with initial moderate ventriculomegaly.

CONCLUSIONS

Among preterm neonates with PHH following severe IVH, elevated CSF hemoglobin, ferritin, and iron were associated with more severe early ventricular enlargement (FOHR > 0.6 vs ≤ 0.6 at first ventricular tap).

Complications and outcomes of posterior fossa decompression with duraplasty versus without duraplasty for pediatric patients with Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

The aim of this study was to determine differences in complications and outcomes between posterior fossa decompression with duraplasty (PFDD) and without duraplasty (PFD) for the treatment of pediatric Chiari malformation type I (CM1) and syringomyelia (SM).

METHODS

The authors used retrospective and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM1-SM who received PFD or PFDD and had at least 1 year of follow-up data. Preoperative, treatment, and postoperative characteristics were recorded and compared between groups.

RESULTS

A total of 692 patients met the inclusion criteria for this database study. PFD was performed in 117 (16.9%) and PFDD in 575 (83.1%) patients. The mean age at surgery was 9.86 years, and the mean follow-up time was 2.73 years. There were no significant differences in presenting signs or symptoms between groups, although the preoperative syrinx size was smaller in the PFD group. The PFD group had a shorter mean operating room time (p < 0.0001), fewer patients with > 50 mL of blood loss (p = 0.04), and shorter hospital stays (p = 0.0001). There were 4 intraoperative complications, all within the PFDD group (0.7%, p > 0.99). Patients undergoing PFDD had a 6-month complication rate of 24.3%, compared with 13.7% in the PFD group (p = 0.01). There were no differences between groups for postoperative complications beyond 6 months (p = 0.33). PFD patients were more likely to require revision surgery (17.9% vs 8.3%, p = 0.002). PFDD was associated with greater improvements in headaches (89.6% vs 80.8%, p = 0.04) and back pain (86.5% vs 59.1%, p = 0.01). There were no differences between groups for improvement in neurological examination findings. PFDD was associated with greater reduction in anteroposterior syrinx size (43.7% vs 26.9%, p = 0.0001) and syrinx length (18.9% vs 5.6%, p = 0.04) compared with PFD.

CONCLUSIONS

PFD was associated with reduced operative time and blood loss, shorter hospital stays, and fewer postoperative complications within 6 months. However, PFDD was associated with better symptom improvement and reduction in syrinx size and lower rates of revision decompression. The two surgeries have low intraoperative complication rates and comparable complication rates beyond 6 months.

Representation of female neurosurgeons as abstract authors at neurological surgery conferences

OBJECTIVE

Female neurosurgeon representation has increased, but women still represent only 8.4% of neurosurgeons in the US. Women are significantly underrepresented as authors in neurosurgical and spine journals, a key indicator of professional success in academic medicine. In this study, the authors aimed to assess the gender diversity of first and last authors of accepted abstracts at neurosurgical conferences in 2015 and 2019.

METHODS

Annual meeting abstracts for 2015 and 2019 of the American Association of Neurological Surgeons (AANS), Congress of Neurological Surgeons (CNS), and pediatrics, spine, stereotactic and functional surgery, and cerebrovascular AANS/CNS subspecialty sections were obtained and analyzed for gender. Partial data were obtained for tumor and pain sections. Composite gender data were obtained from the societies. Percentage differences were calculated using comparison of proportions testing.

RESULTS

Overall, female neurosurgeons accounted for only 8.3% of first and 5.8% of last authors, and 7.2% of authors overall. The pediatrics section had the highest proportion of female neurosurgeons as first (13.7%) and last (12.4%) abstract authors, while the spine section had the lowest proportions of female neurosurgeon first (4.6%) and last (2.0%) authors. Qualitatively, a higher proportion of women were first authors, while a higher proportion of men were last authors. Overall, there was no significant change in female neurosurgeon authorship between 2015 and 2019. With regard to society demographics, female neurosurgeons accounted for only 6.3% of AANS membership. The pediatrics section had the highest proportion of female neurosurgeons at 18.1% and the stereotactic and functional surgery section had the lowest of the subspecialty sections (7.6%). While female neurosurgeons represented 12.6% of spine section membership, they represented only 4.7% of first authors (-7.9% difference; p < 0.0001) and 2.4% of last authors (-10.2% difference; p < 0.0001). For the 2019 cerebrovascular section, female neurosurgeons were underrepresented as presenting authors (5.8%) compared with their membership representation (14.8%, -9.0% difference; p = 0.0018).

CONCLUSIONS

Despite an increase in the number of female neurosurgeons, there has not been a corresponding increase in the proportion of female neurosurgeons as abstract authors at annual neurosurgery conferences, and female neurosurgeons remain underrepresented as authors compared with their male colleagues.

Genetic and histopathological associations with outcome in pediatric pilocytic astrocytoma

OBJECTIVE

Pilocytic astrocytomas (PAs) have a generally favorable prognosis; however, progression or recurrence after resection is possible. The prognostic value of histopathological qualifiers (defined below) or BRAF alterations is not well understood. The aim of this study was to identify the prognostic value of genetic and histopathological features of pediatric PAs.

METHODS

Patients treated for a WHO grade I PA at a single institution were analyzed for histopathological and genetic features and outcomes. "Histopathological qualifier" refers to designations such as "WHO grade I PA with increased proliferative index." BRAF alterations include gene fusions and point mutations. Patients with neurofibromatosis type 1 were excluded.

RESULTS

A total of 222 patients were analyzed (51% female, mean age 9.6 years). Tumors were located in the cerebellum/fourth ventricle (51%), optic pathway/hypothalamus (15%), brainstem (12%), and cerebral cortex (11%). BRAF alterations were screened for in 77 patients and identified in 56 (73%). Histopathological qualifiers were present in 27 patients (14%). Resection was performed in 197 patients (89%), 41 (21%) of whom displayed tumor progression or recurrence after resection. Tumor progression or recurrence was not associated with histopathologic qualifiers (p = 0.36) or BRAF alterations (p = 0.77). Ki-67 proliferative indices were not predictive of progression or recurrence (p = 0.94). BRAF alterations, specifically KIAA1549 fusions, were associated with cerebellar/fourth ventricular tumor location (p < 0.0001) and younger patient age (p = 0.03). Patients in whom gross-total resection was achieved had lower rates of progression and recurrence (p < 0.0001).

CONCLUSIONS

Histopathological features/qualifiers and BRAF alterations were not associated with tumor recurrence/progression in pediatric PAs. The extent of resection was the only factor analyzed that predicted outcome.

Pathogenic variant in NFIA associated with subdural hematomas mimicking nonaccidental trauma

Subdural hematoma (SDH) in infants raises the concern for nonaccidental trauma (NAT), especially when presenting with associated injuries. However, isolated SDH could be caused by multiple etiologies. NFIA (MIM# 600727) encodes nuclear factor I A protein (NFI-A), a transcription factor which plays important roles in gliogenesis. Loss-of-function variants in NFIA are associated with autosomal dominant brain malformations with or without urinary tract defects (MIM# 613735). Intracranial hemorrhage of various types besides SDH has been reported in patients with this condition. Here, we report a patient with a heterozygous novel NFIA pathogenic variant affecting splicing who initially presented with SDH concerning for NAT. We also review previous NFIA-related disorder cases with intracranial hemorrhage. This report emphasizes the importance of genetic evaluation in infants presenting with isolated SDH.

Leptomeningeal disease and tumor dissemination in a murine diffuse intrinsic pontine glioma model: implications for the study of the tumor-cerebrospinal fluid-ependymal microenvironment

Background

Leptomeningeal disease and hydrocephalus are present in up to 30% of patients with diffuse intrinsic pontine glioma (DIPG), however there are no animal models of cerebrospinal fluid (CSF) dissemination. As the tumor-CSF-ependymal microenvironment may play an important role in tumor pathogenesis, we identified characteristics of the Nestin-tumor virus A (Nestin-Tva) genetically engineered mouse model that make it ideal to study the interaction of tumor cells with the CSF and its associated pathways with implications for the development of treatment approaches to address CSF dissemination in DIPG.

Methods

A Nestin-Tva model of DIPG utilizing the 3 most common DIPG genetic alterations (H3.3K27M, PDGF-B, and p53) was used for this study. All mice underwent MR imaging and a subset underwent histopathologic analysis with H&E and immunostaining.

Results

Tumor dissemination within the CSF pathways (ventricles, leptomeninges) from the subependyma was present in 76% (25/33) of mice, with invasion of the choroid plexus, disruption of the ciliated ependyma and regional subependymal fluid accumulation. Ventricular enlargement consistent with hydrocephalus was present in 94% (31/33). Ventricle volume correlated with region-specific transependymal CSF flow (periventricular T2 signal), localized anterior to the lateral ventricles.

Conclusions

This is the first study to report CSF pathway tumor dissemination associated with subependymal tumor in an animal model of DIPG and is representative of CSF dissemination seen clinically. Understanding the CSF-tumor-ependymal microenvironment has significant implications for treatment of DIPG through targeting mechanisms of tumor spread within the CSF pathways.

Syndromic Hydrocephalus

Hydrocephalus, the abnormal accumulation and impaired circulation/clearance of cerebrospinal fluid, occurs as a common phenotypic feature of a diverse group of genetic syndromes. In this review, we outline the genetic mutations, pathogenesis, and accompanying symptoms underlying syndromic hydrocephalus in the context of: L1 syndrome, syndromic craniosynostoses, achondroplasia, NF 1/2, Down's syndrome, tuberous sclerosis, Walker-Warburg syndrome, primary ciliary dyskinesia, and osteogenesis imperfecta. Further, we discuss emerging genetic variants associated with syndromic hydrocephalus.

Does ventricle size contribute to cognitive outcomes in posthemorrhagic hydrocephalus? Role of early definitive intervention

OBJECTIVE

Posthemorrhagic hydrocephalus (PHH) is associated with significant morbidity, smaller hippocampal volumes, and impaired neurodevelopment in preterm infants. The timing of temporary CSF (tCSF) diversion has been studied; however, the optimal time for permanent CSF (pCSF) diversion is unknown. The objective of this study was to determine whether cumulative ventricle size or timing of pCSF diversion is associated with neurodevelopmental outcome and hippocampal size in preterm infants with PHH.

METHODS

Twenty-five very preterm neonates (born at ≤ 32 weeks' gestational age) with high-grade intraventricular hemorrhage (IVH), subsequent PHH, and pCSF diversion with a ventriculoperitoneal shunt (n = 20) or endoscopic third ventriculostomy (n = 5) were followed until 2 years of age. Infants underwent serial cranial ultrasounds from birth until 1 year after pCSF diversion, brain MRI at term-equivalent age, and assessment based on the Bayley Scales of Infant and Toddler Development, Third Edition, at 2 years of age. Frontooccipital horn ratio (FOHR) measurements were derived from cranial ultrasounds and term-equivalent brain MRI. Hippocampal volumes were segmented and calculated from term-equivalent brain MRI. Cumulative ventricle size until the time of pCSF diversion was estimated using FOHR measurements from each cranial ultrasound performed prior to permanent intervention.

RESULTS

The average gestational ages at tCSF and pCSF diversion were 28.9 and 39.0 weeks, respectively. An earlier chronological age at the time of pCSF diversion was associated with larger right hippocampal volumes on term-equivalent MRI (Pearson's r = -0.403, p = 0.046) and improved cognitive (r = -0.554, p = 0.047), motor (r = -0.487, p = 0.048), and language (r = -0.414, p = 0.021) outcomes at 2 years of age. Additionally, a smaller cumulative ventricle size from birth to pCSF diversion was associated with larger right hippocampal volumes (r = -0.483, p = 0.014) and improved cognitive (r = -0.711, p = 0.001), motor (r = -0.675, p = 0.003), and language (r = -0.618, p = 0.011) outcomes. There was no relationship between time to tCSF diversion or cumulative ventricle size prior to tCSF diversion and neurodevelopmental outcome or hippocampal size. Finally, a smaller cumulative ventricular size prior to either tCSF diversion or pCSF diversion was associated with a smaller ventricular size 1 year after pCSF diversion (r = 0.422, p = 0.040, R2 = 0.178 and r = 0.519, p = 0.009, R2 = 0.269, respectively).

CONCLUSIONS

In infants with PHH, a smaller cumulative ventricular size and shorter time to pCSF diversion were associated with larger right hippocampal volumes, improved neurocognitive outcomes, and reduced long-term ventriculomegaly. Future prospective randomized studies are needed to confirm these findings.

Biochemical profile of human infant cerebrospinal fluid in intraventricular hemorrhage and post-hemorrhagic hydrocephalus of prematurity

Background

Intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus (PHH) have a complex pathophysiology involving inflammatory response, ventricular zone and cell–cell junction disruption, and choroid-plexus (ChP) hypersecretion. Increased cerebrospinal fluid (CSF) cytokines, extracellular matrix proteins, and blood metabolites have been noted in IVH/PHH, but osmolality and electrolyte disturbances have not been evaluated in human infants with these conditions. We hypothesized that CSF total protein, osmolality, electrolytes, and immune cells increase in PHH.

Methods

CSF samples were obtained from lumbar punctures of control infants and infants with IVH prior to the development of PHH and any neurosurgical intervention. Osmolality, total protein, and electrolytes were measured in 52 infants (18 controls, 10 low grade (LG) IVH, 13 high grade (HG) IVH, and 11 PHH). Serum electrolyte concentrations, and CSF and serum cell counts within 1-day of clinical sampling were obtained from clinical charts. Frontal occipital horn ratio (FOR) was measured for estimating the degree of ventriculomegaly. Dunn or Tukey’s post-test ANOVA analysis were used for pair-wise comparisons.

Results

CSF osmolality, sodium, potassium, and chloride were elevated in PHH compared to control (p = 0.012 − < 0.0001), LGIVH (p = 0.023 − < 0.0001), and HGIVH (p = 0.015 − 0.0003), while magnesium and calcium levels were higher compared to control (p = 0.031) and LGIVH (p = 0.041). CSF total protein was higher in both HGIVH and PHH compared to control (p = 0.0009 and 0.0006 respectively) and LGIVH (p = 0.034 and 0.028 respectively). These differences were not reflected in serum electrolyte concentrations nor calculated osmolality across the groups. However, quantitatively, CSF sodium and chloride contributed 86% of CSF osmolality change between control and PHH; and CSF osmolality positively correlated with CSF sodium (r, p = 0.55,0.0015), potassium (r, p = 0.51,0.0041), chloride (r, p = 0.60,0.0004), but not total protein across the entire patient cohort. CSF total cells (p = 0.012), total nucleated cells (p = 0.0005), and percent monocyte (p = 0.016) were elevated in PHH compared to control. Serum white blood cell count increased in PHH compared to control (p = 0.042) but there were no differences in serum cell differential across groups. CSF total nucleated cells also positively correlated with CSF osmolality, sodium, potassium, and total protein (p = 0.025 − 0.0008) in the whole cohort.

Conclusions

CSF osmolality increased in PHH, largely driven by electrolyte changes rather than protein levels. However, serum electrolytes levels were unchanged across groups. CSF osmolality and electrolyte changes were correlated with CSF total nucleated cells which were also increased in PHH, further suggesting PHH is a neuro-inflammatory condition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-021-00295-8.

Socioeconomic and demographic factors in the diagnosis and treatment of Chiari malformation type I and syringomyelia

OBJECTIVE

The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM).

METHODS

The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes.

RESULTS

A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively).

CONCLUSIONS

Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

Neurosurgical Considerations of Neurocutaneous Syndromes

The phakomatoses are a group of genetic and acquired disorders characterized by neurologic, cutaneous, and often ocular manifestations, thus commonly referred to as neurocutaneous syndromes. In several of these conditions the underlying genetic pathophysiology has been elucidated, which will continue to play an important role in advancing therapeutic techniques. This article focuses on several examples of such neurocutaneous syndromes, with special attention to the relevant neurosurgical considerations of these patients.

Longitudinal scoliosis behavior in Chiari malformation with and without syringomyelia

OBJECTIVE

The objective of this study was to understand the natural history of scoliosis in patients with Chiari malformation type I (CM-I) with and without syringomyelia.

METHODS

A retrospective review of data was conducted. Patients with CM-I were identified from a cohort of 14,118 individuals age 18 years or younger who had undergone MRI over an 11-year period at the University of Michigan. Patients eligible for study inclusion had a coronal curve ≥ 10° on radiography, associated CM-I with or without syringomyelia, and at least 1 year of clinical follow-up prior to any surgery. Curve magnitude at initial diagnosis, prior to posterior fossa decompression (PFD; if applicable), and at the last follow-up (prior to any surgical correction of scoliosis) was recorded, and clinical and radiographic characteristics were noted. The change in curve magnitude by 10° was defined as curve progression (increase by 10°) or regression (decrease by 10°).

RESULTS

Forty-three patients met the study inclusion criteria and were analyzed. About one-third (35%) of the patients presented with symptoms attributed to their CM-I. The mean degree of scoliosis at presentation was 32.6° ± 17.7°. Twenty-one patients (49%) had an associated syrinx. The mean tonsil position below the level of the foramen magnum was 9.8 ± 5.8 mm. Patients with a syrinx were more likely to have a curve > 20° (86% vs 41%, p = 0.002). Curve magnitude remained stable (≤ ±10°) in 77% of patients (33/43), progressed in 16% (7/43), and regressed in 7% (3/43). Mean age was higher (14.8 ± 0.59 years) among patients with regressed curves (p = 0.026). All regressed curves initially measured ≤ 20° (mean 14° ± 5.3°), and none of the patients with regressed curves had a syrinx. The change in curve magnitude was statistically similar in patients with (7.32° ± 17.7°) and without (5.32° ± 15.8°) a syrinx (p = 0.67). After a mean follow-up of 3.13 ± 2.04 years prior to surgery, 27 patients (63%) ultimately underwent posterior fossa or scoliosis correction surgery. For those who eventually underwent PFD only, the rate of change in curve magnitude prior to surgery was 0.054° ± 0.79°. The rate of change in curve magnitude was statistically similar before (0.054° ± 0.79°) and after (0.042° ± 0.33°) surgery (p = 0.45) for patients who underwent PFD surgery only.

CONCLUSIONS

The natural history of scoliosis in the presence of CM-I is variable, though most curves remained stable. All curves that regressed were ≤ 20° at initial diagnosis, and most patients in such cases were older at scoliosis diagnosis. Patients who underwent no surgery or PFD only had similar profiles for the change in curve magnitude, which remained relatively stable overall, as compared to patients who underwent PFD and subsequent fusion, who demonstrated curve progression. Among the patients with a syrinx, no curves regressed, most remained stable, and some progressed. Understanding this variability is a first step toward building a prediction model for outcomes for these patients.

Longitudinal CSF Iron Pathway Proteins in Posthemorrhagic Hydrocephalus: Associations with Ventricle Size and Neurodevelopmental Outcomes

OBJECTIVE

Iron has been implicated in the pathogenesis of brain injury and hydrocephalus after preterm germinal matrix hemorrhage-intraventricular hemorrhage, however, it is unknown how external or endogenous intraventricular clearance of iron pathway proteins affect the outcome in this group.

METHODS

This prospective multicenter cohort included patients with posthemorrhagic hydrocephalus (PHH) who underwent (1) temporary and permanent cerebrospinal fluid (CSF) diversion and (2) Bayley Scales of Infant Development-III testing around 2 years of age. CSF proteins in the iron handling pathway were analyzed longitudinally and compared to ventricle size and neurodevelopmental outcomes.

RESULTS

Thirty-seven patients met inclusion criteria with a median estimated gestational age at birth of 25 weeks; 65% were boys. Ventricular CSF levels of hemoglobin, iron, total bilirubin, and ferritin decreased between temporary and permanent CSF diversion with no change in CSF levels of ceruloplasmin, transferrin, haptoglobin, and hepcidin. There was an increase in CSF hemopexin during this interval. Larger ventricle size at permanent CSF diversion was associated with elevated CSF ferritin (p = 0.015) and decreased CSF hemopexin (p = 0.007). CSF levels of proteins at temporary CSF diversion were not associated with outcome, however, higher CSF transferrin at permanent CSF diversion was associated with improved cognitive outcome (p = 0.015). Importantly, longitudinal change in CSF iron pathway proteins, ferritin (decrease), and transferrin (increase) were associated with improved cognitive (p = 0.04) and motor (p = 0.03) scores and improved cognitive (p = 0.04), language (p = 0.035), and motor (p = 0.008) scores, respectively.

INTERPRETATION

Longitudinal changes in CSF transferrin (increase) and ferritin (decrease) are associated with improved neurodevelopmental outcomes in neonatal PHH, with implications for understanding the pathogenesis of poor outcomes in PHH. ANN NEUROL 2021;90:217-226.

Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression.

METHODS

A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty.

RESULTS

In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion.

CONCLUSIONS

In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

A multicenter validation of the condylar-C2 sagittal vertical alignment in Chiari malformation type I: a study using the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

The condylar-C2 sagittal vertical alignment (C-C2SVA) describes the relationship between the occipitoatlantal joint and C2 in patients with Chiari malformation type I (CM-I). It has been suggested that a C-C2SVA ≥ 5 mm is predictive of the need for occipitocervical fusion (OCF) or ventral brainstem decompression (VBD). The authors' objective was to validate the predictive utility of the C-C2SVA by using a large, multicenter cohort of patients.

METHODS

This validation study used a cohort of patients derived from the Park-Reeves Syringomyelia Research Consortium; patients < 21 years old with CM-I and syringomyelia treated from June 2011 to May 2016 were identified. The primary outcome was the need for OCF and/or VBD. After patients who required OCF and/or VBD were identified, 10 age- and sex-matched controls served as comparisons for each OCF/VBD patient. The C-C2SVA (defined as the position of a plumb line from the midpoint of the O-C1 joint relative to the posterior aspect of the C2-3 disc space), pBC2 (a line perpendicular to a line from the basion to the posteroinferior aspect of the C2 body), and clival-axial angle (CXA) were measured on sagittal MRI. The secondary outcome was the need for ≥ 2 CM-related operations.

RESULTS

Of the 206 patients identified, 20 underwent OCF/VBD and 14 underwent repeat posterior fossa decompression. A C-C2SVA ≥ 5 mm was 100% sensitive and 86% specific for requiring OCF/VBD, with a 12.6% misclassification rate, whereas CXA < 125° was 55% sensitive and 99% specific, and pBC2 ≥ 9 was 20% sensitive and 88% specific. Kaplan-Meier analysis demonstrated that there was a significantly shorter time to second decompression in children with C-C2SVA ≥ 5 mm (p = 0.0039). The mean C-C2SVA was greater (6.13 ± 1.28 vs 3.13 ± 1.95 mm, p < 0.0001), CXA was lower (126° ± 15.4° vs 145° ± 10.7°, p < 0.05), and pBC2 was similar (7.65 ± 1.79 vs 7.02 ± 1.26 mm, p = 0.31) among those who underwent OCF/VBD versus decompression only. The intraclass correlation coefficient for the continuous measurement of C-C2SVA was 0.52; the kappa value was 0.47 for the binary categorization of C-C2SVA ≥ 5 mm.

CONCLUSIONS

These results validated the C-C2SVA using a large, multicenter, external cohort with 100% sensitivity, 86% specificity, and a 12.6% misclassification rate. A C-C2SVA ≥ 5 mm is highly predictive of the need for OCF/VBD in patients with CM-I. The authors recommend that this measurement be considered among the tools to identify the "high-risk" CM-I phenotype.