Fetal Repair Research Articles

Contemporary Outcomes of a National Fetal Spina Bifida Surgery Service.

To assess contemporary outcomes of fetuses who underwent open fetal spina bifida surgery in Canada. Our clinical program prospectively collected outcomes of all consecutive fetuses who underwent open fetal spina bifida closure at the Ontario Fetal Center in Toronto and who were at least 1year of age at the time of postnatal follow-up. We gathered information on the need for hydrocephalus treatment, motor function, bladder function, as well as neurodevelopment (Ages and Stages Questionnaire and Bayley's scales of infant development). Developmental outcomes were categorized as "Typical Development," "Possible Delay," or "Significantly Delayed." Between 2017 and 2022, 41 fetuses underwent open fetal spina bifida closure. Twenty-four patients (58.5%) responded to the questionnaire at a median age of 46.5months. Eight children (33.3%) required CSF diversion procedures. Bladder management included clean intermittent catheterization (43.5%), spontaneous voiding (34.8%), or both (21.7%), with 43.5% needing medication for overactive bladder. All patients could sit independently, with 50% walking outside and 50% crawling indoors. Among those walking outdoors (50%), 25% did so without orthotics or aid, 58.3% with orthotics, and 16.7% required additional walking aids. Most children demonstrated typical communication and problem-solving skills (79.2%), while gross motor development was significantly delayed in 91.7% of cases. Fine motor skills varied, with 56.5% showing typical development and 34.8% possibly experiencing delays. This study showed a mixed developmental profile among patients who underwent open fetal spina bifida repair, consistent with the MOMs trial findings.

Prenatal Surgery for Open Fetal Spina Bifida in Patients with Obesity: A Review of Current Evidence and Future Directions.

Background: Obesity rates have significantly increased globally, affecting up to 40% of women of childbearing age in the United States. While prenatal repair of open fetal spina bifida has shown improved outcomes, most fetal surgery centers exclude patients with a body mass index (BMI) ≥ 35 kg/m2 based on criteria from the Management of Myelomeningocele Study (MOMS) trial. This exclusion raises concerns about healthcare equity and highlights a significant knowledge gap regarding the safety and efficacy of fetal spina bifida repair in patients with obesity. Objective: To review the current state of knowledge regarding open fetal surgery for fetal spina bifida in patients with obesity, focusing on safety, efficacy, and clinical considerations. Methods: A comprehensive literature search was conducted using the PubMed and EMBASE databases, covering articles from the inception of the databases to April 2024. Studies discussing fetal surgery for neural tube defects and documenting BMI measurements and their impact on surgical outcomes, published in peer-reviewed journals, and available in English were included. Quantitative data were extracted into an Excel sheet, and data synthesis was conducted using the R programming language (version 4.3.3). Results: Three retrospective studies examining outcomes of prenatal open spina bifida repair in a total of 43 patients with a BMI ≥ 35 kg/m2 were identified. These studies did not report significant adverse maternal or fetal outcomes compared to patients with lower BMIs. Our pooled analysis revealed a perinatal mortality rate of 6.1% (95% CI: 1.76-18.92%), with 28.0% (95% CI: 14.0-48.2%) experiencing the premature rupture of membranes and 82.0% (95% CI: 29.2-98.0%) delivering preterm (<37 weeks). Membrane separation was reported in 10.3% of cases (95% CI: 3.3-27.7%), the mean gestational age at birth was 34.3 weeks (95% CI: 32.3-36.3), and the average birth weight was 2651.5 g (95% CI: 2473.7-2829.4). Additionally, 40.1% (95% CI: 23.1-60.0%) required a ventriculoperitoneal shunt. Conclusion: While current evidence suggests that fetal spina bifida repair may be feasible in patients with obesity, significant limitations in the existing body of research were identified. These include small sample sizes, retrospective designs, and a lack of long-term follow-up data. There is an urgent need for large-scale, prospective, multicenter studies to definitively establish the safety and efficacy of fetal spina bifida repair in patients with obesity. Such research is crucial for developing evidence-based guidelines, improving clinical outcomes, and addressing healthcare disparities in this growing patient population with obesity.

OSBA: An Open Neonatal Neuroimaging Atlas and Template for Spina Bifida Aperta

We present the Open Spina Bifida Aperta (OSBA) atlas, an open atlas and set of neuroimaging templates for spina bifida aperta (SBA). Traditional brain atlases may not adequately capture anatomical variations present in pediatric or disease-specific cohorts. The OSBA atlas fills this gap by representing the computationally averaged anatomy of the neonatal brain with SBA after fetal surgical repair. The OSBA atlas was constructed using structural T2-weighted and diffusion tensor MRIs of 28 newborns with SBA who underwent prenatal surgical correction. The corrected gestational age at MRI was 38.1 ± 1.1 weeks (mean ± SD). The OSBA atlas consists of T2-weighted and fractional anisotropy templates, along with nine tissue prior maps and region of interest (ROI) delineations. The OSBA atlas offers a standardized reference space for spatial normalization and anatomical ROI definition. Our image segmentation and cortical ribbon definition are based on a human-in-the-loop approach, which includes manual segmentation. The precise alignment of the ROIs was achieved by a combination of manual image alignment and automated, non-linear image registration. From the clinical and neuroimaging perspective, the OSBA atlas enables more accurate spatial standardization and ROI-based analyses and supports advanced analyses such as diffusion tractography and connectomic studies in newborns affected by this condition.

Prenatal Neurosurgical Counseling for Myelomeningocele and Treatment-Determining Factors for Fetal Repair.

Spina bifida guidelines recommend neurosurgical involvement in prenatal counseling (nPNC) to inform decision-making between prenatal and postnatal MMC repair. This study examines whether families with myelomeningocele (MMC) presenting to one fetal center had timely nPNC encounters, and assesses modifiable and non-modifiable treatment-determining factors. History and timing of nPNC were quantified among infants undergoing postnatal and prenatal MMC repair, pregnant patients referred, and MMC studies in a fetal MRI database (2015-2023). Fetal repair exclusions, presentation timing, social determinants, and reported rationale for not selecting offered fetal therapy were assessed. Nearly all patients (34/35; 97%) engaged in nPNC, 82% prior to 24 weeks GA. Fourteen patients were excluded from fetal repair for lack of hindbrain herniation (43%), obstetric exclusions (21%), fetal exclusions (21%), suspected closed defect (7%), and delayed presentation (7%). These patients ultimately underwent postnatal repair (71%), and pregnancy termination (14%). The 20 fetal-repair-eligible patients selected fetal repair (50%), postnatal repair (45%), and pregnancy termination (5%). Reasons for declining fetal repair included risk (55%) and cost (22%). Among MMC families presenting to a regional fetal therapy center, nPNC was widely extended, in a mostly timely fashion. Very few were deterred from fetal repair by potentially modifiable barriers.

MRI analysis of neurodevelopmental anatomy in myelomeningocele: prenatal vs postnatal repair.

Compared with postnatal repair, prenatal myelomeningocele (MMC) repair is associated with improved motor function and decreased need for cerebrospinal fluid (CSF) diversion. It is unknown how prenatal surgery alters neuroanatomical structures identifiable on magnetic resonance imaging (MRI). The purpose of this study was to use MRI to compare neurodevelopmental anatomy in patients undergoing fetal MMC repair compared with those undergoing postnatal repair. This was a retrospective review of neonates who underwent prenatal or postnatal MMC repair at our institution between 2016 and 2021. Imaging data, including prenatal ultrasound and pre- and postnatal MRI examinations, if available, were retrieved. We analyzed anatomical findings characteristically seen on MRI of the neuroaxis in patients with MMC and compared imaging findings between patients with prenatal vs postnatal MMC repair. The study population included 61 patients who underwent surgical repair for MMC during the 6-year study period, of whom 25 underwent prenatal repair and 36 postnatal repair. CSF diversion was required in 24% of the prenatally repaired cohort vs 67% of the postnatally repaired cohort (P = 0.001). On postnatal MRI, a syrinx was present in 13% of the prenatally repaired cohort vs 42% in the postnatally repaired cohort (P = 0.02). Postnatal corpus callosal (CC) morphology was abnormal in 54% of the prenatally repaired cohort vs 53% of the postnatally repaired cohort (P = 0.92), while falx morphology was normal in 92% of the prenatally repaired cohort vs 34% of the postnatally repaired cohort (P < 0.001). On postnatal MRI, patients in the prenatally repaired cohort had a shorter tentorium-to-foramen-magnum distance compared with those in the postnatally repaired cohort (mean, 18.43 mm vs 22.42 mm; P = 0.01), a larger foramen magnum diameter (mean, 22.87 mm vs 18.94 mm; P < 0.001) and a smaller degree of hindbrain herniation (mean, 1.53 mm vs 8.72 mm; P < 0.001). The cerebral aqueduct was patent in 79% of the prenatally repaired cohort vs 100% of the postnatally repaired cohort on postnatal MRI (P = 0.008). Between the two cohorts, at postnatal MRI there was no significant difference in the presence of gray-matter heterotopia, presence of the septum pellucidum or size of the massa intermedia. We report variations in developmental neuroanatomy in patients with MMC, including rates of CC dysgenesis, gray-matter heterotopia and additional cranial and spinal MRI findings. Compared to postnatal surgery, prenatal surgery is associated with changes to infratentorial anatomy, with minimal effect on supratentorial brain development. This information will be useful in counseling parents affected by fetal MMC and in understanding how prenatal repair of MMC affects brain development. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Chorioamniotic Membrane Separation after Fetal Spina Bifida Repair: Impact of CMS Size and Patient Management.

Chorioamniotic membrane separation (CMS) is a known complication after fetal spina bifida (fSB) repair. This study's goal was to analyze women's outcomes with open fSB repair and CMS (group A) compared to the ones without (group B) and to assess the influence of CMS size and patient management. A total of 194 women with open fSB repair at our center were included in this retrospective study. Outcomes of group A were compared to the ones of group B. Regression analysis was performed to assess risk factors for CMS. Two subgroup analyses assessed the impact of CMS size (small [A-small] vs. large [A-large]) as well as patient management (A1 = hospitalization vs. A2 = no hospitalization) on pregnancy outcomes. Of 194 women, 23 (11.9%) were in group A and 171 (88.1%) in group B. Preterm premature rupture of membranes (PPROMs) (69.6% vs. 24.1%, p = &lt;0.001), amniotic infection syndrome (AIS) (22.7% vs. 7.1%, p = 0.03), histologically confirmed chorioamnionitis (hCA) (40.0% vs. 14.7%, p = 0.03), length of hospital stay (LOS) after fSB repair (35 [19-65] vs. 17 [14-27] days), and overall LOS (43 [33-71] vs. 35 [27-46] days, p = 0.004) were significantly more often/longer in group A. Gestational age (GA) at delivery was significantly lower in group A compared to group B (35.3 [32.3-36.3] vs. 36.7 [34.9-37.0] weeks, p = 0.006). Regression analysis did not identify risk factors for CMS. Subgroup analysis comparing CMS sized in group A-small versus A-large showed higher AIS rate (42% vs. 0%, p = 0.04), lower LOS (22.0 [15.5-42.5] vs. 59.6 ± 24.1, p = 0.003). Comparison of group A1 versus A2 showed longer LOS (49.3 ± 22.8 vs. 15 [15-17.5] days, p &lt; 0.001), lower planned readmission rate (5.6% vs. 80%, p = 0.003). CMS significantly increased the risk of PPROM, AIS, hCA, caused longer LOS, and caused lower GA at delivery. Women with small CMS had higher AIS rates but shorter LOS compared to women with large CMS, while apart from LOS pregnancy outcomes did not differ regarding patient management (hospitalization after CMS yes vs. no).

Sleep-disordered breathing on respiratory polygraphy in neonates with spina bifida.

Studies have shown a high prevalence of sleep-disordered breathing (SDB) in children with spina bifida. International standards for regular testing for SDB in this population are lacking. While there are studies investigating the prevalence of SDB in children with spina bifida, there are close to no studies in neonates. To evaluate if routine respiratory polygraphy (RPG) testing is indicated for neonates with spina bifida and if yes, with what therapeutic consequence. We conducted a retrospective cohort study of all neonates with spina bifida at the University (Children's) Hospital Zurich after fetal spina bifida repair born between 2017 and 2022, who had undergone at least 1 RPG evaluation during hospitalization on the neonatal ward. RPG were evaluated by a blinded group of experienced pediatric pulmonologists. Based on the neonatal RPG results and pediatric pulmonologist's recommendation for caffeine therapy the spina bifida cohort was divided into two groups. Neonatal baseline RPG and follow-up RPG at the age of the 3 months were evaluated. 48 neonates with RPG were included. Compared to the standard values in healthy neonates, the RPG results of this spina bifida cohort showed findings of SDB with central apnea and hypopnea. 22 (45.8%) neonatal RPG evaluations detected central SDB, prompting caffeine therapy. Follow-up RPG conducted after 3 months showed significant improvement of SDB with (almost) no need for continuation of caffeine. We recommend the implementation of routine RPG testing in neonates with spina bifida to detect SDB and facilitate early targeted treatment.

Middle Cerebral Artery Doppler before and after Fetal Spina Bifida Repair: An Indirect Sign of Hindbrain Compression and Decompression?

Reduced middle cerebral artery resistance indices (MCA-RI) in fetuses with spina bifida (fSB) are commonly observed. Compression of neuronal pathways in the brainstem due to hindbrain herniation (HH) and disturbed cerebrospinal fluid circulation likely cause an imbalance of the autonomic nervous system. This may increase systemic vasoconstriction and compensatory increase cerebral vasodilation (like brain sparing). The aim of this study was to systematically analyze all fetal MCA-RI before and after fSB repair and to compare their correlation with the presence and postsurgical resolution of HH. 173 patients were included. Standardized ultrasound examinations including MCA and umbilical artery (UA) Doppler as well as assessment of HH presence and regression were performed. Fetuses with MCA-RI &lt;5th percentile (P) before fetal surgery were compared to the group with normal MCA-RI and correlated to the presence of HH before and its regression after fSB repair. 30% (49/161) fetuses showed RI's &lt;5th P before fSB repair. All fetuses had normal UA-RI. 99.4% of fetuses (160/161) showed normal of MCA-RI before delivery. Normalization occurred within a mean of 1.3 ± 1.2 weeks. HH regression was observed in 97% in the group with normal MCA-RI and in 96% in the group with MCA-RI &lt;5th P before surgery (p = 0.59). Time lapse to HH regression after fSB repair was 1.8 ± 1.7 and 1.9 ± 1.6 weeks, respectively. In fetuses with MCA-RIs &lt;5 P before fSB repair, a parallel timely course of MCA-RI normalization and HH regression was noted. To suggest common pathogenic factor(s), more studies are needed. However, normalization of the fetal cerebral circulation could be a further benefit of fSB repair.

Health Disparities and Route of Repair of Fetal Myelomeningocele-Prenatal Versus Postnatal Repair

Background: Spina bifida (SB) is a relatively common birth defect with the highest prevalence among Hispanics. A randomized controlled trial (MOMS) demonstrated that prenatal repair yielded improved outcomes compared to postnatal repair. However, the social determinants of health can significantly impact the overall well-being of affected individuals or their eligibility for some of these evidenced-based interventions. Methods: We conducted a retrospective observational study to describe and compare the mean Child Opportunity Index (COIs) scores among patients treated at a free-standing children’s hospital who underwent either prenatal or postnatal repair of SB from January 1&amp;lt;sup&amp;gt;st&amp;lt;/sup&amp;gt;, 2012, to December 31&amp;lt;sup&amp;gt;st&amp;lt;/sup&amp;gt;, 2021. We excluded patients with identifiable maternal and fetal contraindications to prenatal repair, as per the MOMS trial eligibility, apart from those pertaining to socio-economic status. RESULTS: Among a total cohort of 51 fetuses, 86% (n = 44) underwent postnatal repair for SB, while 14% (n = 7) received prenatal repair. Patients who underwent prenatal repair exhibited lower COI scores across all domains (education, health, and environment, social and economic) on national, state, and metro levels compared to the postnatal group. Our cohort showed a higher percentage of primary commercial insurance in the prenatal (fetal) surgery group (57.14%) versus the postnatal surgery group (47.73%), without attaining statistical significance (p=0.25). Conclusion: While COI scores across all domains were lower in the prenatal cohort, our data does not suggest a statistically significant difference between prenatal and postnatal surgery groups. This highlights the need for future studies with larger sample sizes to further explore and define this relationship.

Treatment of hydrocephalus following fetal repair of myelomeningocele: comparing endoscopic third ventriculostomy with choroid plexus cauterization to ventricular shunting.

The aim of this study was to compare clinical and craniometric outcomes of patients treated for hydrocephalus following fetal myelomeningocele repair (fMMR) via a ventriculoperitoneal shunt (VPS) or endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC). This was a retrospective cohort study of children who were treated for hydrocephalus following fMMR via VPS or ETV with or without CPC (ETV ± CPC) at Vanderbilt between 2012 and 2021. The primary outcomes were treatment failure and time to failure (TTF). Secondary outcomes included changes in hydrocephalus metrics (fronto-occipital horn ratio [FOHR] and head circumference measurements) and healthcare resource utilization (number of hospital admissions, clinic visits, and neuroimaging findings). Among 88 patients who underwent fMMR, 37 (42%) required permanent CSF diversion, of whom 19 received treatment at the authors' institution. Twelve patients underwent ETV ± CPC, and 7 underwent VPS placement at a median corrected age of 23 weeks versus 1 week (p = 0.002). The preoperative median head circumference percentiles and z-scores for patients in the ETV ± CPC cohort were similar to those of the VPS cohort (percentiles: 98.5 vs 94.0, p = 0.064; z-scores: 2.32 vs 1.60, p = 0.111). There was no difference in preoperative median FOHR measurements between the two cohorts (0.57 vs 0.59, p = 0.53). At 6 months postoperatively, the median head circumference percentile and z-score for the ETV ± CPC cohort remained similar between the two cohorts (percentiles: 98.0 vs 67.5, p = 0.315; z-scores: 2.12 vs 0.52, p = 0.307). There was no difference in the change in FOHR (-0.06 vs -0.09, p = 0.37) and change in head circumference percentile (-1.33 vs -28.6, p = 0.058) between the cohorts 6 months after the index CSF diversion procedure. One patient in the ETV ± CPC cohort experienced a seizure and a nonoperative subdural hemorrhage postoperatively; no other complications were observed. Six of the 7 patients in the VPS cohort required shunt revision with a median TTF of 9.8 months while 2 of the 12 ETV ± CPC patients required a repeat ETV at a median of 17.5 months (86% vs 17%, p = 0.013). The median number of hydrocephalus-related hospital readmissions was significantly lower in the ETV ± CPC cohort than in the VPS cohort (0 vs 1, p = 0.006). The ETV ± CPC cohort had fewer CT scans (0 vs 2, p = 0.004) and radiographs (0 vs 2, p < 0.001) than the VPS cohort. In a single-center cohort, hydrocephalic fMMR patients treated via ETV ± CPC remained shunt free, while a majority of patients receiving an upfront shunt required revision. This is the first study comparing ETV ± CPC with VPS in the fMMR hydrocephalus population. While larger, multicenter studies are needed, these results suggest that ETV/CPC may be a preferred means of CSF diversion following fMMR.

Morphometric Analysis of Spina Bifida after Fetal Repair Shows New Subtypes with Associated Outcomes.

The binary classification of spina bifida lesions as myelomeningocele (with sac) or myeloschisis (without sac) belies a spectrum of morphologies, which have not been correlated to clinical characteristics and outcomes. To characterize spina bifida lesion types and correlate them with preoperative presentation and postoperative outcomes. Secondary analysis of images and videos obtained during fetoscopic spina bifida repair surgery from 2020-2023. Fetal surgery was performed at a quaternary care center. A prospective cohort of patients referred for fetal spina bifida underwent fetoscopic repair under an FDA-approved protocol. Of 60 lesions repaired, 57 had available images and were included in the analysis. We evaluated lesion morphology on high-resolution intraoperative images and videos to categorize lesions based on placode exposure and nerve root stretching. The reproducibility of the lesion classification was assessed via Kappa interrater agreement. Preoperative characteristics analyzed include ventricle size, tonsillar herniation level, lower extremities movement, and lesion dimensions. Outcomes included surgical time, need for patch for skin closure, gestational age at delivery, preterm premature rupture of membranes (PPROM), and neonatal cerebrospinal fluid (CSF) diversion. We distinguished five lesion types that differ across a range of sac sizes, nerve root stretching, and placode exposure, with 93% agreement between examiners (p<0.001). Fetal characteristics at preoperative evaluation differed significantly by lesion type, including lesion volume (p<0.001), largest ventricle size (p=0.008), tonsillar herniation (p=0.005), and head circumference (p=0.03). Lesion level, talipes, and lower extremities movement did not differ by type. Surgical and perinatal outcomes differed by lesion type, including need for patch skin closure (p<0.001), gestational age at delivery (p=0.01), and NICU length of stay (p<0.001). PPROM, CSF leakage at birth, and CSF diversion in the NICU did not differ between lesion groups. Linear regression associated severity of ventriculomegaly with lesion type, but not with tonsillar herniation level. There is a distinct phenotypic spectrum in open spina bifida with differential baseline presentation and outcomes. Severity of ventriculomegaly is associated with lesion type, rather than tonsillar herniation level. Our findings expand the classification of spina bifida to reveal a spectrum that warrants further study.

Periventricular nodular heterotopia in patients with a prenatal diagnosis of myelomeningocele/myeloschisis: associations with seizures and neurodevelopmental outcomes during early childhood.

Historically, the presence of gray matter heterotopia was a concern for adverse postnatal neurocognitive status in patients undergoing fetal closure of open spinal dysraphism. The purpose of this study was to evaluate neurodevelopmental outcomes and the onset of seizures during early childhood in patients with a prenatal diagnosis of myelomeningocele/myeloschisis (MMC) and periventricular nodular heterotopia (PVNH). All patients evaluated at the Center for Fetal Diagnosis and Treatment with a diagnosis of MMC between June 2016 to March 2023 were identified. PVNH was determined from prenatal and/or postnatal MRI. The Bayley Scales of Infant and Toddler Development (edition III or IV) were used for neurodevelopmental assessments. Patients were screened for seizures/epilepsy. Of 497 patients evaluated with a prenatal diagnosis of MMC, 99 were found to have PVNH on prenatal MRI, of which 35 had confirmed PVNH on postnatal imaging. From the 497 patients, 398 initially did not exhibit heterotopia on prenatal MRI, but 47 of these then had confirmed postnatal PVNH. The presence of PVNH was not a significant risk factor for postnatal seizures in early childhood. The average neurodevelopmental scores were not significantly different among heterotopia groups for cognitive, language, and motor domains. The presence of PVNH in patients with a prenatal diagnosis of MMC does not indicate an increased risk for neurodevelopmental delay at 1year of age. We did not demonstrate an association with seizures/epilepsy. These findings can aid clinicians in prenatal consultation regarding fetal repair of open spinal dysraphism. Long-term follow-up is required to discern the true association between PVNH seen on prenatal imaging and postnatal seizures/epilepsy and neurodevelopmental outcomes.

263 Radiographic Structural Changes in Brain Anatomy of Pediatric Fetal Versus Postnatal Myelomeningocele Repair Patients

INTRODUCTION: Postnatally repaired myelomeningocele (MMC) patients have twice the risk of needing shunt treatment for hydrocephalus compared to fetally repaired patients, however it is unknown why exactly this occurs as well as what structural brain changes may be predictive of hydrocephalus. We radiographically characterized anatomic changes in fetally vs postnatally treated infants to understand early developmental anatomy. METHODS: MRIs were characterized by two board-certified neuroradiologists for the following variables: 1) The ratio of ventricular-to-subarachnoid space (VSAR) using bifrontal (BF), left frontal lobe thickness (LV), and extra-axial (EA) spaces as parameters. 2) The ratio of 2 planes within the lateral ventricle (LVR). These ratios, elongation of the choroid plexus glomus and body, and Chiari were measured. RESULTS: 54 MMC repair patients met criteria, yielding 109 MRIs. In the one-to-three month time frame, VSAR at BF and LV parameters in addition to LVR were all significantly different in the fetally repaired group (n = 14) compared to the postnatally repaired group (n = 13, p&lt;0.05). VSAR was not significantly different in early life. Chiari was significantly different in the early life and one-to-three month time between fetal and postnatal repair cohorts (p &lt; 0.05). CONCLUSIONS: Fetally and postnatally repaired MMC brain MRIs were examined by two neuroradiologists to characterize differences in early brain development. This study identified significant differences in the ventricular to subarachnoid space ratio during the one-to-three month time point between fetally and postnatally repaired patients. We suspect that subarachnoid anatomy may be predictive of the need for surgical treatment of hydrocephalus.

130 Heterotopia and Neurodevelopmental Outcomes Patients With Prenatal Diagnosis of Myelomeningocele or Myeloschisis

INTRODUCTION: Gray matter heterotopia is a cortical malformation and a known risk factor for seizures and epilepsy. Historically, presence of heterotopia in one or both cerebral ventricles was a concern for postnatal neurological status in patients undergoing fetal closure of myelomeningocele/myeloschisis. There is little information known regarding the overall impact of heterotopia in this patient population. METHODS: A retrospective chart review was conducted for all patients evaluated at the Center of Fetal Diagnosis and Treatment with a diagnosis of myelomeningocele or myeloschisis between June 2016 to March 2023. Gray matter heterotopia was determined from prenatal US and confirmed with prenatal and postnatal MRI. The Bayley Scales of Infant and Toddler Development (edition III and IV) were used for neurodevelopmental assessments. RESULTS: Of 497 patients evaluated with a prenatal diagnosis of myelomeningocele or myeloschisis, 99 were found to have gray matter heterotopia on prenatal MRI. In the postnatal period, 347 patients ultimately delivered at our institution, of which 26 had confirmed gray matter heterotopia on postnatal MRI as well as underwent neurodevelopmental testing. The median age at neurodevelopmental assessment was 13.3 months. The median cognitive and language scores (95 and 99, respectively) were average in those patients with gray matter heterotopia. CONCLUSIONS: This study suggests that the presence of gray matter heterotopia in patients with prenatal diagnosis of myelomeningocele or myeloschisis is not associated with increased cognitive or language delay on neurodevelopmental testing at approximately 1 year of age. These findings can aid clinicians during prenatal consultation regarding fetal repair of spina bifida.

275 Absence of Hindbrain Herniation in Myelomeningocele Myeloschisis: A Closer Look at Patients Who Progress to Hindbrain Herniation in the Prenatal and Postnatal Period

INTRODUCTION: Prenatal repair is the gold standard for appropriate patients with fetal myelomeningocele/myeloschisis. Hindbrain herniation is a prerequisite for fetal repair; however, there is a subset of patients without herniation on initial imaging and then progress to herniation on subsequent prenatal/postnatal imaging. METHODS: From July 2016 to July 2022, patients seen at the Center of Fetal Diagnosis and Treatment for myelomeningocele/myeloschisis were evaluated for hindbrain herniation. The osseous lesion level was defined as the bony defect level on prenatal ultrasound. Prenatal sac volume was measured on MRI. Prenatal ventricular size was determined on US. The fronto-occipital horn ratio was measured on the first postnatal US. RESULTS: Of 422 patients identified with a prenatal diagnosis of myelomeningocele/myeloschisis, 73 were identified who initially had negative hindbrain herniation; of these, 9 and 11 patients progressed to herniation on subsequent prenatal and postnatal imaging, respectively; 32 remained without herniation throughout the prenatal/postnatal period. Sac volume was significant (p = 0.04) for those whose hindbrain herniation was detected on subsequent prenatal visits but not for those diagnosed in the postnatal period (p = 0.10). The majority of patients with hindbrain herniation progression had L1-2 lesions. A subset of patients ultimately underwent permanent CSF diversion (no herniation: 21.8%, prenatal herniation: 33.3%, postnatal herniation: 36.3%). CONCLUSIONS: Patients who initially exhibit no hindbrain herniation and then ultimately progress to herniation in subsequent prenatal or postnatal evaluation are more likely to have higher levels of osseous defect. Sac volume was determined as significant for delayed prenatal progression of hindbrain herniation. Further long-term outcomes are necessary to better characterize this unique cohort of patients.

Comparison of terbutaline and atosiban as tocolytic agents in intrauterine repair of myelomeningocele: a retrospective cohort study

BackgroundMyelomeningocele (MMC) is a neural tube defect disease. Antenatal repair of fetal MMC is an alternative to postnatal repair. Many agents can be used as tocolytics during the in utero fetal repair such as β2-agonists and oxytocin receptor antagonists, with possible maternal and fetal repercussions. This study aims to compare maternal arterial blood gas analysis between terbutaline or atosiban, as tocolytic agents, during intrauterine MMC repair. MethodsRetrospective cohort study. Patients were divided into two groups depending on the main tocolytic agent used during intrauterine MMC repair: atosiban (16) or terbutaline (9). Maternal arterial blood gas samples were analyzed on three moments: post induction (baseline, before the start of tocolysis), before extubation, and two hours after the end of the surgery. ResultsTwenty-five patients were included and assessed. Before extubation, the terbutaline group showed lower arterial pH (7.347 ± 0.05 vs. 7.396 ± 0.02 for atosiban, p = 0.006) and higher arterial lactate (28.33 ± 12.76 mg.dL−1 vs. 13.06 ± 6.35 mg.dL−1, for atosiban, p = 0.001) levels. ConclusionsPatients who received terbutaline had more acidosis and higher levels of lactate, compared to those who received atosiban, during intrauterine fetal MMC repair.

Length of hysterotomy for fetal spina bifida repair is associated with prematurity risk.

To investigate whether prenatal repair of spina bifida aperta through mini-hysterotomy results in less prematurity, as compared to standard hysterotomy, when adjusting for known prematurity risks. We performed a bi-centric, propensity score matched, controlled study, that is, adjusting for factors earlier reported to result in premature delivery or membrane rupture, in consecutive women having prenatal repair either through stapled hysterotomy or sutured mini-hysterotomy (≤3.5cm). Matches were pairwise compared and cox-regression analysis was performed to define the hazard ratio of delivery <37weeks. Of 346 meeting the MOMS-criteria, 78 comparable pairs were available for matched-controlled analysis. Mini-hysterotomy patients were younger and had a higher BMI. Mini-hysterotomy was associated with a 1.67-lower risk of delivery <37weeks (hazard ratio: 0.60; 95% CI: 0.42-0.85; p=0.004) and 1.72 for delivery <34+6weeks (hazard ratio: 0.58; 95% CI: 0.34-0.97; p=0.037). The rate of intact uterine scar at birth (mini-hysterotomy: 98.7% vs. hysterotomy: 90.4%; p=0.070), the rate of reversal of hindbrain herniation within 1week after surgery (88.9% vs. 97.4%; p=0.180) and the rate of cerebrospinal fluid leakage (0% vs. 2.7%; p=0.50) were comparable. Prenatal spina bidifa repair through mini-hysterotomy was associated with a later gestational age at delivery and a comparable intact uterus rate without apparent compromise in neuroprotection.

Fetal In-Utero Microneurosurgical Repair of Myelomeningocele and Myeloschisis: Neursurgical Outcome Updated

Conference presented at the Brazilian Academy of Neurosurgery Pediatric Symposium on December 9th, 2024. Myelomeningocele (MMC) is recognized as the most prevalent neural tube defect (NTD) and the most complex congenital anomaly that is still consistent with life. In the era of folic acid fortification, its incidence has been observed at 3.4 per 10,000 live births. The observed decrease in incidence is attributed to a synergy of enhanced folate supplementation, along with advancements in prenatal diagnostics, and, in certain cases, the option of selective termination. Recently, innovative technology and growing expertise have sparked considerable excitement within the scientific community regarding fetal MMC repair. In this lecture, Dr. Elbabaa shares his surgical outcomes and provides an updated overview of the current state of the art in this surgical field.

Fetal surgery for spina bifida – An upcoming standard of care

Open spina bifida or myelomeningocele (MMC) is one of the most common serious congenital malformations that have been historically treated with a repair after birth. However, this “repair” does not avert neurological injury, reverse hindbrain herniation, or prevent hydrocephalus. With the intention to reduce numerous medical procedures, lifelong morbidities, and medical complications, fetal surgery was proposed about a quarter century ago. Fetal surgery has become the standard of care for MMC, especially after the advent of the Management of Myelomeningocele Study (MOMS) trial. Dr. Michael Harrison from the University of California was the first to birth this idea in the 1980s. While earlier research was carried out on ovine models, it was deduced that intrauterine repair reduces the secondary damage to exposed neural tissue and improves post-natal neurological outcomes. After the promising results in animal models and some clinical series, it paved the way for a prospective multicenter randomized controlled trial that compared prenatal versus postnatal MMC repair, with the aim to prove its efficacy and safety with Level-1 evidence- the MOMS. However, it was stopped early due to the improved prenatal repair outcomes, thus establishing open fetal MMC repair as the standard of care. We aim to discuss the origin story of this remarkable procedure, its rationales and advantages for the unborn child and mother and its short-term and long-term superiority and limitations. The operative procedure and the criteria with other essential aids in its diagnosis have also been discussed briefly. We also intend to eliminate the apprehension faced toward this procedure by the supporting team of obstetricians, anesthetists, neonatologists, and radiologists essential to making this procedure a success.

805 Morphometric analysis of spina bifida (SB) to associate pre-operative severity and clinical outcomes after fetal repair

805 Morphometric analysis of spina bifida (SB) to associate pre-operative severity and clinical outcomes after fetal repair