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OBJECTIVE Despite in utero spina bifida (SB) repair, more than two-thirds of patients with SB are unable to ambulate independently, and 1 in 4 children need surgery for tethered cord by school age. The objective of this study was to test the cryopreserved human umbilical cord (HUC) as an antiscarring material to reduce tethering and improve function in a modified in utero SB repair model. METHODS An SB defect (L2–6 levels) without myelotomy was created in fetuses of timed-pregnant ewes at gestational day (GD) 75. On GD 96, the fetal defect was exposed, and the arachnoid layer was removed to disrupt the barrier and expose the spinal cord to simulate human in utero SB repair. The fetuses were randomly assigned to two groups according to the method used to cover the spinal cord: the conventional repair (CR) group, for which myofascial closure was used (n = 7), and the HUC meningeal patch group, for which HUC was used as a meningeal patch (n = 6), followed by primary skin closure. The lambs were delivered at GD 140. Blinded clinical assessment of spinal cord function was performed using the Texas Spinal Cord Injury Scale (TSCIS). Histology of the spine was performed for quantitative assessment of spinal cord tethering, inflammatory markers, and arachnoid layer regeneration. RESULTS The TSCIS scores were significantly lower in the CR than the HUC meningeal patch group (p = 0.0015) and the controls (p = 0.0018). The loss of spinal cord function in the CR group was mainly due to ataxia and loss of proprioception (p = 0.01 and 0.005 vs control and HUC, respectively). The histology at the repair site showed higher rates of spinal cord tethering in the CR lambs than the HUC lambs at all levels of the repair site (p = 0.01 and 0.02 vs control and HUC, respectively). In the CR with tethering compared with the HUC repair, there was a lower arachnoid layer covering at the repair site (p = 0.001). There was greater astrocyte activation in the posterior column in the CR than in the HUC repair group (p = 0.01). CONCLUSIONS In a modified ovine SB model, the HUC as a meningeal patch allows regeneration of the arachnoid layer, prevents spinal cord tethering, and improves spinal cord function after in utero SB repair.

OBJECTIVE The aim of this study was to determine whether reversal of hindbrain herniation (HBH) on MRI following prenatal repair of neural tube defects (NTDs) is associated with reduced rates of ventriculoperitoneal (VP) shunt placement or endoscopic third ventriculostomy (ETV) within the 1st year of life. METHODS This is a secondary analysis of prospectively collected data from all patients who had prenatal open repair of a fetal NTD at a single tertiary care center between 2012 and 2020. Patients were offered surgery according to inclusion criteria from the Management of Myelomeningocele Study (MOMS). Patients were excluded if they were lost to follow-up, did not undergo postnatal MRI, or underwent postnatal MRI without a report assessing hindbrain status. Patients with HBH reversal were compared with those without HBH reversal. The primary outcome assessed was surgical CSF diversion (i.e., VP shunt or ETV) within the first 12 months of life. Secondary outcomes included CSF leakage, repair dehiscence, CSF diversion prior to discharge from the neonatal intensive care unit (NICU), and composite neonatal morbidity. Demographic, prenatal sonographic, and operative characteristics as well as outcomes were assessed using standard univariate statistical methods. Multivariate logistic regression models were fit to assess for independent contributions to the primary and secondary outcomes. RESULTS Following exclusions, 78 patients were available for analysis. Of these patients, 38 (48.7%) had HBH reversal and 40 (51.3%) had persistent HBH on postnatal MRI. Baseline demographic and preoperative ultrasound characteristics were similar between groups. The primary outcome of CSF diversion within the 1st year of life was similar between the two groups (42.1% vs 57.5%, p = 0.17). All secondary outcomes were also similar between groups. Patients who had occurrence of the primary outcome had greater presurgical lateral ventricle width than those who did not (16.1 vs 12.1 mm, p = 0.02) when HBH was reversed, but not when HBH was persistent (12.5 vs 10.7 mm, p = 0.49). In multivariate analysis, presurgical lateral ventricle width was associated with increased rates of CSF diversion before 12 months of life (adjusted OR 1.18, 95% CI 1.03–1.35) and CSF diversion prior to NICU discharge (adjusted OR 1.18, 95% CI 1.02–1.37). CONCLUSIONS HBH reversal was not associated with decreased rates of CSF diversion in this cohort. Predictive accuracy of the anticipated benefits of prenatal NTD repair may not be augmented by the observation of HBH reversal on MRI.

Supplementary Data from SAR405838: A Novel and Potent Inhibitor of the MDM2:p53 Axis for the Treatment of Dedifferentiated Liposarcoma