Cerebral Abnormalities in Spina Bifida: A Neuropathological Study

Introduction Spina bifida (SB) is the most common neural tube defect in humans. Here, we analyzed systematically the neuropathological findings of the brain in SB cases. Methods 79 cases with SB aperta (SBA) and 6 cases with SB occulta (SBO) autopsied at the Charité Neuropathology from 1974 to 2000 were re-evaluated retrospectively. For this, case files and spinal cord as well as brain sections were studied. Results While no brain malformations were detected in SBO cases, 95% of SBA cases had brain malformations. Main brain anomalies identified were hydrocephalus (71%), Chiari II malformation (36%), heterotopia (34%), other cerebellar anomalies (36%), gyrification defects (33%), and ependymal denudation (29%). Hydrocephalus was observed as early as gestational week 17 and was highly associated to Chiari II and ependymal denudation. In 55% SBA was accompanied by further anomalies not primarily affecting the CNS. Conclusion We confirm using neuropathologic methods brain malformations in most SBA but none in SBO cases. In addition to our previous radiologic study, we now demonstrate the high prevalence of cerebellar malformations and cerebral heterotopias in SBA. The early detection of hydrocephalus and Chiari II malformation in fetuses raises the question whether these arise parallel rather than in strict temporal sequence.

Care management and contemporary challenges in spina bifida: a practice preference survey of the American Society of Pediatric Neurosurgeons

OBJECTIVENeurosurgical management preferences related to myelomeningocele (MMC) care demonstrate significant variability. The authors sought to evaluate variability in practice patterns across a group of senior pediatric neurosurgeons. The purpose of this study was to identify the extent of variability and of consensus with regard to neurosurgical management of MMC and associated hydrocephalus, Chiari II malformation, and tethered spinal cord.METHODSA 43-question survey was distributed electronically to the members of the American Society of Pediatric Neurosurgeons (ASPN). The survey covered domains such as clinic case volume, newborn management, hydrocephalus management, transition to adulthood, clinical indications for shunt revision, Chiari II malformation decompression (C2MD), and tethered cord release (TCR). Ninety responses were received from 200 active ASPN members, for an overall response rate of 45%.RESULTSThe majority (58%) of respondents closed 5–15 new cases of open MMC per year. Nearly all (98%) respondents perform back closure within 48 hours of birth, with the majority imbricating the placode and striving for a 3- to 4-layer closure. The most consistent indications for surgical intervention in early hydrocephalus were CSF leak from the back (92%), progressive ventricular enlargement (89%), and brainstem symptoms, including apnea/bradycardia (81%), stridor (81%), and dysphagia (81%). Eighty percent of respondents indicated that spina bifida care is delivered through multidisciplinary clinics, with neurosurgery, orthopedic surgery, urology, physical therapy, and social work as the most common disciplines included. One-third of clinics see both pediatric and adult patients, one-third offer a formal transition program to adult care, and one-third have no transition program. The vast majority of respondents offer prenatal counseling (95%), referral for in utero closure (66%), and endoscopic third ventriculostomy/choroid plexus cauterization (72%). Respondents were more willing to perform shunt revision for symptoms alone than for image changes alone. An asymptomatic broken shunt without ventricular enlargement produced responses evenly divided between observation, intervention, and further investigation. Operative shunt exploration was always performed before C2MD by 56% of respondents and performed sometimes by 40% of respondents. Symptoms of brainstem dysfunction were the strongest clinical triggers reported for C2MD, while declines in urinary continence, leg strength or sensation, or ambulation were the most consistent thresholds for TCR.CONCLUSIONSSignificant disparities exist surrounding key areas of decision making regarding treatment for patients with MMC, though there are central areas of agreement among ASPN members. Additionally, there is significant variation in the clinical management of chronic hydrocephalus, C2MD, and TCR, underscoring the need for further research into these specific areas.

Myelomeningocele Repair

Myelomeningocele (MMC) is a spinal birth defect associated with significant morbidity directly related to the exposure of meninges and neural structures. Further neurological dysfunction may occur secondary to Chiari II malformation and hydrocephalus. MMC repair is typically performed postnatally within the first 24 to 48 hours of life due to the concern for infection. Prenatal MMC correction is performed in select cases after studies showed improved neurological outcomes. Anesthesia for MMC repairs can be challenging, and appropriate screening should be performed preoperatively. During postnatal repair, care must be taken when positioning the infant to avoid any pressure on the MMC sac. Anesthesia can be maintained with a combination of inhalational agents and intravenous opioids. Prenatal MMC repairs must consider both fetal and maternal safety outcomes. They can be performed through both open and fetoscopic routes, with anesthesia focused on maintaining maternal blood pressure, optimizing uterine relaxation, and adequate pain control.