Lim, Foong‐Yen Y.

BACKGROUND AND OBJECTIVES: Myelomeningocele is defined by the presence of a fluid-filled sac that contains the neural placode and cerebrospinal fluid (CSF) at the level of the spinal defect. Alternatively, the term myeloschisis is used when the neural placode is not contained within a CSF-filled sac. While both are eligible for prenatal closure, few studies have characterized the impact of the type of lesion on postnatal outcomes. This study compares the outcomes of these 2 types of open spinal dysraphism using data from the Fetal Myelomeningocele Consortium registry sponsored by the North American Fetal Therapy Network. METHODS: The prospective observational Fetal Myelomeningocele Consortium registry was used to extract deidentified data corresponding to patients who underwent fetal closure of myelomeningocele vs myeloschisis. Demographics, operative characteristics, perioperative complications, and postnatal outcomes were collected. RESULTS: A total of 1327 patients were identified, including 991 (74.7%) with myelomeningocele and 336 (25.3%) with myeloschisis. Compared with myelomeningocele, myeloschisis was associated with lower rates of prenatal talipes (11% vs 24%, P < .001) and higher rates of favorable prenatal movement (94% vs 86%, P < .001). Postnatally, myeloschisis conferred higher rates of leg movement (97% vs 90%, P = .002) and an increased likelihood of ambulation in the household (10.4% vs 4.1%, P = .009) and outside (7.2% vs 1.9%, P = .004) at 1 year. However, myeloschisis was also linked to greater use of skin patches during closure (49% vs 27%, P < .001), higher CSF leak rates among those with wound dehiscence (26% vs 8%, P = .014), and more frequent CSF diversion and tethered cord surgeries at follow-up. CONCLUSION: Myeloschisis and myelomeningocele demonstrate distinct clinical profiles. Although patients with myeloschisis may have favorable motor outcomes, they are also characterized by higher rates of CSF leakage, CSF diversion, and tethered cord surgery. These findings highlight the need for lesion-specific prognostication and may inform surgical planning and parental counseling in the context of prenatal spina bifida closure.

BACKGROUND AND OBJECTIVES: The Management of Myelomeningocele Study established a role for maternal-fetal surgery for myelomeningocele (MMC) but was limited to patients with a maternal body mass index (BMI) less than 35 kg/m 2 . However, as the rate of obesity has increased globally, some centers have extended the Management of Myelomeningocele Study criteria to include patients with a BMI of 35 to 40 kg/m 2 . We used the Fetal MMC Consortium registry to analyze the complications associated with maternal-fetal surgery in patients with a maternal BMI < 35 kg/m 2 compared with 35 to 40 kg/m 2 . METHODS: The prospective observational Fetal MMC Consortium registry sponsored by the North American Fetal Therapy Network was used to extract deidentified “maternal complication” and “fetal/neonatal complication” data sets, corresponding to patients with complete entries related to maternal or fetal/neonatal complications, respectively. Demographics, clinical characteristics, and complications were recorded. Propensity score matching was conducted with a 2:1 algorithm, and outcomes were compared between patients with BMI < 35 kg/m 2 and those with BMI 35 to 40 kg/m 2 . RESULTS: Propensity score matching resulted in 156 patients with BMI < 35 kg/m 2 and 78 patients with BMI 35 to 40 kg/m 2 in the “maternal complication” data set, and 130 patients with BMI < 35 kg/m 2 and 65 patients with BMI 35 to 40 kg/m 2 in the “fetal/neonatal complication” data set. No significant differences in the median number of maternal (2.0 vs 2.0; P = .257) or median number of fetal/neonatal (1.0 vs 1.0; P = .409) complications were observed between the 2 cohorts. Furthermore, prematurity rates did not differ significantly between the BMI < 35 and BMI 35 to 40 cohorts. CONCLUSION: Maternal-fetal surgery for open neural tube defect closure is not associated with increased risks among patients with a maternal BMI of 35 to 40 kg/m 2 . Extending the initial inclusion criteria for prenatal MMC closure has the potential to expand access to patients with a higher risk for open neural tube defects.

Abstract Objective In utero fetal spina bifida repair decreases the risk for cerebrospinal fluid (CSF) diversion including ventriculoperitoneal (VP) shunt placement, reverses hindbrain herniation, and improves motor function with a higher likelihood of independent ambulation. Unfortunately, in utero surgery can be complicated by preterm delivery. The goal of this study was to compare pregnancy and neonatal outcomes between individuals who delivered very preterm, and those who delivered later in gestation following in utero spina bifida repair. Methods Data from the North American Fetal Therapy Network Fetal Myelomeningocele Consortium Registry collected from 2011 to 2024 were analyzed. Three cohorts of patients were categorized by gestational age at delivery and compared: <30 weeks, 30–34 weeks, and >34 weeks. Comparisons between groups for maternal and delivery outcomes were completed for the entire cohort and then analyzed for those with available CSF diversion data up to 1 year of life. Chi‐square or Fisher's exact tests were used to compare categorical variables, and Kruskal–Wallis tests were used to determine if there are significant differences between the distributions of the three groups. A p ‐value <0.05 was considered significant. Results A total of 1213 patients were analyzed (<30 weeks, n = 111 [9.2%]; 30–34 weeks, n = 323 [26.6%]; >34 weeks, n = 779 [64.2%]). Overall fetal and neonatal mortality was 2.2%, 85% of which occurred in the <30‐week cohort, where perinatal mortality was 21%. Latency from fetal surgery to delivery averaged 2.1 weeks for the <30‐week group. Rates of abruption, chorioamnionitis, and spontaneous labor were higher in the <30‐week group compared to later gestational age cohorts. Neonatal morbidity was also significantly higher in the <30‐week cohort for sepsis, apnea, respiratory distress, patent ductus arteriosus, intraventricular hemorrhage, and periventricular leukomalacia in the <30‐week cohort. CSF diversion data were available for 677 neonates (<30 weeks, n = 53; 30–34 weeks, n = 186; >34 weeks, n = 438). There was no significant difference in VP shunt placement between the different gestational age groups. Conclusion Very preterm birth following in utero spina bifida repair results in significant perinatal mortality and neonatal morbidity. Delivery prior to 30 weeks of gestation occurs in 9% of patients after in utero spina bifida repair, resulting in a 21% perinatal mortality rate. However, even among those who delivered very preterm, a reduction in VP shunt rates, a benefit of in utero repair, appears to be preserved. Further data are warranted to assess the impact of prematurity following in utero surgery on ambulation and developmental outcomes.

AbstractObjectiveTo evaluate variability in antenatal sonographic prognostication of congenital diaphragmatic hernia (CDH) within the North American Fetal Therapy Network (NAFTNet).MethodsNAFTNet centre were invited to complete a questionnaire and participate in videoconference calls, during which participants were observed while measuring lung area by ultrasound using the anteroposterior (AP) method, longest method, and trace method. Each center identified 1–2 experienced fetal medicine specialist(s) or medical imaging specialists locally to participate in the study. Practices were compared among NAFTNet centre within and without the fetal endoscopic tracheal occlusion (FETO) consortium.ResultsNineteen participants from 9 FETO center and 30 participants from 17 non‐FETO center completed the survey and 31 participants were interviewed and observed while measuring sonographic lung area. All Centres measured observed‐to‐expected lung‐to‐head ratio (o/e LHR) or LHR for CDH prognostication. Image selection criteria for lung area measurement were consistent, including an axial section of the chest with clear lung borders and a 4‐chamber cardiac view. Lung area measurement methods varied across NAFTNet, with most centre using longest (4/9 FETO vs. 13/29 non‐FETO) or trace (3/9 FETO vs. 11/29 non‐FETO) method. Centres differed in expected reference ranges for o/e LHR determination and whether the lowest, highest or average o/e LHR was utilized.ConclusionVariability in antenatal sonographic prognostication of CDH was identified across NAFTNet, indicating a need for consensus‐based standardization.