A child with unilateral abducens nerve palsy and neurovascular compression in Chiari malformation type 1 resolved with posterior fossa decompression: illustrative case.

BACKGROUND: Unilateral cranial nerve (CN) VI, or abducens nerve, palsy is rare in children and has not been reported in association with Chiari malformation type 1 (CM1) in the absence of other classic CM1 symptoms. OBSERVATIONS: A 3-year-old male presented with acute incomitant esotropia consistent with a unilateral, left CN VI palsy and no additional neurological symptoms. Imaging demonstrated CM1 without hydrocephalus or papilledema, as well as an anterior inferior cerebellar artery (AICA) vessel loop in the immediate vicinity of the left abducens nerve. Given the high risk of a skull base approach for direct microvascular decompression of the abducens nerve and the absence of other classic Chiari symptoms, the patient was initially observed. However, as his palsy progressed, he underwent posterior fossa decompression with duraplasty (PFDD), with the aim of restoring global cerebrospinal fluid dynamics and decreasing possible AICA compression of the left abducens nerve. Postoperatively, his symptoms completely resolved. LESSONS: In this first reported case of CM1 presenting as a unilateral abducens palsy in a young child, possibly caused by neurovascular compression, the patient's symptoms resolved after indirect surgical decompression via PFDD.

Postnatal Myelomeningocele Repair in the United States: Rates and Disparities Before and After the Management of Myelomeningocele Study Trial.

BACKGROUND AND OBJECTIVES: Evolving technologies have influenced the practice of myelomeningocele repair (MMCr), including mandatory folic acid fortification, advances in prenatal diagnosis, and the 2011 Management of Myelomeningocele Study (MOMS) trial demonstrating benefits of fetal over postnatal MMCr in select individuals. Postnatal MMCr continues to be performed, especially for those with limitations in prenatal diagnosis, health care access, anatomy, or personal preference. A comprehensive, updated national perspective on the trajectory of postnatal MMCr volumes and patient disparities is absent. We characterize national trends in postnatal MMCr rates before and after the MOMS trial publication (2000-2010 vs 2011-2019) and examine whether historical disparities persist. METHODS: This retrospective, cross-sectional analysis queried Nationwide Inpatient Sample data for postnatal MMCr admissions. Annual and race/ethnicity-specific rates were calculated using national birth registry data. Time series analysis assessed for trends relative to the year 2011. Patient, admission, and outcome characteristics were compared between pre-MOMS and post-MOMS cohorts. RESULTS: Between 2000 and 2019, 12 426 postnatal MMCr operations were estimated nationwide. After 2011, there was a gradual, incremental decline in the annual rate of postnatal MMCr. Post-MOMS admissions were increasingly associated with Medicaid insurance and the lowest income quartiles, as well as increased risk indices, length of stay, and hospital charges. By 2019, race/ethnicity-adjusted rates seemed to converge. The mortality rate remained low in both eras, and there was a lower rate of same-admission shunting post-MOMS. CONCLUSION: National rates of postnatal MMCr gradually declined in the post-MOMS era. Medicaid and low-income patients comprise an increasing majority of MMCr patients post-MOMS, whereas historical race/ethnicity-specific disparities are improving. Now more than ever, we must address disparities in the care of MMC patients before and after birth.

Reappraisal of intradural findings in Chiari malformation type I.

OBJECTIVE: Management of Chiari malformation type I (CM-I) requires the functional restoration of an obstructed cisterna magna. In posterior fossa decompression with duraplasty (PFDD), various intradural pathologies are suggested to alter CSF flow at the craniocervical junction and require surgical correction. However, reports of the spectrum of intraoperative intradural findings and their nuances are scarce, especially those characterizing rarer findings pertaining to the vascular structures and vascular compression. METHODS: The authors conducted a retrospective cohort analysis of adults and children who underwent first-time PFDD for CM-I (2011-2021), with and without syringomyelia. The surgical reports and intraoperative videos were reviewed, and the frequency and nature of the intradural observations in regard to the tonsils, arachnoid, and vasculature were analyzed along with the clinical findings and surgical outcomes. RESULTS: All 180 patients (age range 1-72 years; median [interquartile range] 24 (14-38) years; 37% of patients were children < 21 years of age) exhibited multiple intradural findings, with a median of 7 distinct concurrent observations in each patient. Novel findings not previously reported included posterior inferior communicating artery (PICA) branches compressing the neural elements at the cervicomedullary junction (26.7%). Other common findings included arachnoid adhesions (92.8%), thickening (90.6%), webs at the obex (52.2%), tonsillar gliosis (57.2%), tonsillar hypertrophy (18.3%), adhesions obstructing the foramen of Magendie (FoM) (62.2%), PICA obstruction of the FoM (17.2%), and dural scarring (87.8%). Tonsillar gliosis and intertonsillar adhesions obstructing the FoM were more common in children than adults. Tonsillar gliosis and arachnoid webs were more common among syringomyelia patients. After multivariable adjustment, none of the observed findings were independently associated with syringomyelia, preoperative symptoms, or postoperative improvement. The vast majority of patients improved postoperatively. The complication rate was low: 1.2% of patients required revision PFDD at > 3 years postoperatively, 3.6% experienced other operative complications, and 0% had CSF leaks. CONCLUSIONS: The diversity of intradural findings and observations revealed in this study suggests that obstructive and compressive structural anomalies may be more common than previously reported among CM-I patients, both those patients with and those without syringomyelia and especially those with obstructive and compressive PICA branches. Although the authors cannot conclude that all these findings are necessarily pathological, further study may determine how they contribute to CM-I pathology and symptomatology in the setting of a compromised cisterna magna.

Compromised Cranio-Spinal Suspension in Chiari Malformation Type 1: A Potential Role as Secondary Pathophysiology.

In Chiari Malformation Type I (CM1), low-lying tonsils obstruct the cisterna magna at the foramen magnum, thereby compromising the essential juncture between the cranial and spinal compartments. The anatomical obstruction of the cisterna magna inhibits bi-directional CSF flow as well as CSF pulse pressure equilibration between the intracranial compartment and the intraspinal compartment in response to instances of increased intracranial pressure. Less understood, however, are the roles of the spinal cord suspension structures at the craniocervical junction which lend viscoelastic support to the spinal cord and tonsils, as well as maintain the anatomical integrity of the cisterna magna and the dura. These include extradural ligaments including the myodural bridges (MDBs), as well as intradural dentate ligaments and the arachnoid framework. We propose that when these elements are disrupted by the cisterna magna obstruction, tonsillar pathology, and altered CSF dynamics, there may arise a secondary pathophysiology of compromised and dysfunctional cranio-spinal suspension in CM1. We present intraoperative images and videos captured during surgical exposure of the craniocervical junction in CM1 to illustrate this proposal.

Rare sacral extradural grade II ependymoma: a comprehensive review of literature.

Sacral spinal cord ependymoma is an uncommon pathology. Most of the reported cases are consistent with a myxopapillary ependymoma histopathologic subtype. Non-myxopapillary ependymomas rarely occur in the sacral region. Most lesions are intradural; however, rare extradural cases can occur. We present the case of a 46-year-old female patient diagnosed with a grade II sacral extradural ependymoma, emphasising the importance of an interdepartmental case approach for diagnosis and management. Even though grade II ependymomas are considered low grade, the potential for recurrence and metastatic disease has been reported. There are no treatment guidelines for these rare tumours besides gross total resection.

Risk Factors for Developing Hydrocephalus in Neonatal Intraventricular Hemorrhage.

OBJECTIVE: More than 50% of the premature infant survivors of intraventricular hemorrhage (IVH) develop serious neurological sequelae, including progressive posthemorrhagic hydrocephalus (PPHH) requiring a ventriculo-peritoneal (VP) shunt. Little is known about the risk factors associated with the development of PPHH in the neonatal population of Puerto Rico and thus the purpose of this study was to learn more about those risk factors. METHODS: We performed a retrospective analysis on neonates born from 2013 through 2017 who had been diagnosed with IVH. The data extracted included gender, gestational age at birth, birth weight, IVH grade, and whether the child had required a VP shunt. RESULTS: Two hundred and sixty-one survivors of neonatal IVH were included in the study. The overall mortality rate was 19.4%, and the incidence of PPHH was 7.7% (N = 20). The results from the Fisher's exact test for the association between the development of PPHH and the independent variables of gender (p = 0.06), birth weight (p = 0.18), and gestational age (p = 0.21) were not statistically significant. Binomial logistic regression showed that subjects with IVH (grades 3 and 4) were 20 times more likely to exhibit PPHH. CONCLUSION: The incidence of PPHH secondary to IVH was slightly lower in our population compared to such incidence in other populations reported in the literature; however, the overall mortality rate was similar. The only statistically significant associated risk factor for PPHH was the severity of the IVH.

Descriptive Study of Aneurysmal and Nonaneurysmal Subarachnoid Hemorrhage and the Role of Confirmative Digital Subtraction Angiography in Patients with Nonaneurysmal Subarachnoid in Puerto Rico.

BACKGROUND: Cerebrovascular disease is the fifth cause of mortality in Puerto Rico. There is no descriptive study for the presentation of spontaneous subarachnoid hemorrhage (SAH) in our institution. Therefore, our primary aim was to perform a retrospective analysis of adult patients with spontaneous SAH and assess the need for digital subtraction angiography (DSA) after initially aneurysm-negative computed tomography angiography (CTA) in nonaneurysmal SAH, specifically perimesencephalic SAH (PM-SAH). METHODS: Medical records of 324 adult patients with aneurysmal and nonaneurysmal SAH treated at the Puerto Rico Medical Center from 2015 to 2018 were retrospectively analyzed. Demographics, past medical history, clinical characteristics, and imaging information were extracted. RESULTS: Acute hydrocephalus, mortality at 30 days, prevalence of diffuse SAH pattern, and Fisher and World Federation of Neurosurgical Societies grades >2 on initial examination were higher in the aneurysmal SAH subgroup. Patients with nonaneurysmal SAH had a significantly higher prevalence of chronic kidney disease and diabetes mellitus. Of the patients with nonaneurysmal PM-SAH with initial aneurysm-negative CTA, 100% were subsequently confirmed by DSA. CONCLUSIONS: Patients in the aneurysmal SAH subgroup correlated with an increased disease burden. Furthermore, this study shows that in our population, patients with nonaneurysmal PM-SAH with a low Fisher and World Federation of Neurosurgical Societies grade and with comorbid diabetes mellitus and chronic kidney disease may not need DSA after a negative initial CTA result.