Long-term neurofunctional outcome, executive functioning, and behavioral adaptive skills following fetal myelomeningocele surgery

Impact of Prenatal Repair for Fetal Myelomeningocele on Gastrointestinal Function

OBJECTIVES

To assess the impact of postnatal, open fetal, and fetoscopic repairs for open neural tube defects (ONTDs) on bowel function and to assess the use of diet modification and medication use to achieve regular bowel function.

STUDY DESIGN

A retrospective cohort study was performed from 2011 to 2020 at our academic referral fetal center. Patients were stratified by route of surgery (postnatal, open prenatal, or fetoscopic prenatal). Bowel function was assessed by patient reported Bristol stool scale as well as a detailed review of current medication usage for bowel management. Patient demographics and clinically relevant outcomes were obtained from electronic medical records. The primary outcome was bowel function assessed at 30-month follow up visit.

RESULTS

A total of 150 patients with fetal ONTD underwent repair at our institution. Forty-eight (32%) underwent postnatal repair, 34 (23%) open fetal surgery, and 68 (45%) fetoscopic repair. Eighty-six patients (57%) reported abnormal bowel function at 30 months of life. No differences were noted in abnormal bowel function between surgical approaches (postnatal 35% vs open prenatal 26%, and fetoscopic 49%, P = .08). Patients who underwent postnatal repair were more likely to require oral regimens to achieve normal bowel function compared with either prenatal surgery approach (postnatal 83% vs open prenatal 59%, and fetoscopic 69%, P = .046).

CONCLUSION

Abnormal bowel function remains a significant morbidity regardless of surgical approach for ONTD. Fetal surgery (open or fetoscopic) for ONTD may result in equivalent bowel function when compared with postnatal repair.

The Intrauterine Treatment of Open Spinal Dysraphism

BACKGROUND

Open spinal dysraphism is a congenital malformation that causes major morbidity. Its consequences include sensory and motor impairment as well as bladder- and bowel dysfunction. It is often also associated with prenatal ventriculomegaly, which, in turn, necessitates postnatal treatment with a ventriculoperitoneal shunt in approximately 80% of cases. Prenatal therapy with coverage of neural tube defect can reduce the shunt rate and preserve motor function. In this review, we describe the different surgical procedures and their outcomes.

METHODS

This review is based on publications that were retrieved by a selective literature search in the MEDLINE, Web of Science, EMBASE, Scopus, and Cochrane databases, employing pertinent keywords. Studies of all types (except case reports) that were published in English or German in the period 2010-2024 were included.

RESULTS

The randomized, controlled MOMS trial showed that intrauterine surgery for defect closure resulted in less progressive neural tissue damage than postnatal surgery and reduced the need for shunting by approximately half (40% vs. 82%). Since the publication of these results, various prenatal surgical procedures have been established, including hysterotomy-assisted, percutaneous fetoscopic, and laparotomy-assisted fetoscopic closure. The individual surgical methods yield comparable results in terms of motor function and shunt rate. A problem with these procedures is that they increase the likelihood of preterm birth, to an extent that varies from one type of procedure to another.

CONCLUSION

Prenatal surgery improves motor function and reduces the shunt rate but long-term outcomes beyond adolescence are still lacking. Transparent and interdisciplinary counseling is essential in prenatal communication to inform parents not only about the potential benefits of this treatment, but also about its limitations and risks.

Ambulation after in-utero fetoscopic or open neural tube defect repair: predictors for ambulation at 30 months

OBJECTIVES

To compare the ambulatory status of a cohort of children who had undergone prenatal repair of an open neural tube defect (ONTD) using one of two different methods (fetoscopic or open hysterotomy) with that of a cohort who had undergone postnatal repair, and to identify the best predictors of ambulation at 30 months of age.

METHODS

This was a retrospective review of a cohort of children who underwent ONTD repair either prenatally (n = 110), by fetoscopic surgery (n = 73) or open hysterotomy surgery (n = 37), or postnatally (n = 51), in a single tertiary hospital between November 2011 and May 2023. The cohort comprised a consecutive sample of cases who had undergone ONTD repair in-utero following Management of Myelomeningocele Study (MOMS) trial criteria and cases who had undergone postnatal repair, meeting the same criteria, which were also followed up after birth at the same institution. Motor function assessment by ultrasound was recorded at referral, 6 weeks after prenatal repair, or after referral in postnatally repaired cases, and at the last ultrasound scan before delivery. Clinical examinations to assess motor function at birth and at 12 months were retrieved from records. Intact motor function was defined as first sacral myotome (S1) motor function. Ambulatory status data at each follow-up visit were collected. The proportion of children who were able to walk independently after 30 months of age was compared between those who had undergone fetoscopic vs open prenatal surgery and between prenatal (by either fetoscopic or open surgery) and postnatal ONTD repair. Logistic regression analyses were performed to identify predictors for independent ambulation.

RESULTS

After 30 months, the proportion of infants who were able to walk independently was higher in prenatally vs postnatally repaired cases (51.8% vs 15.7%, P < 0.01), and there was no difference between those with fetoscopic (52.1%) vs open (51.4%) prenatal repair (P = 0.66). In the prenatally repaired group, having intact motor function at 12 months (adjusted odds ratio (aOR), 9.14 (95% CI, 2.64-31.63), P < 0.01) and at birth (aOR, 4.50 (95% CI, 1.21-16.80), P = 0.02) were significant predictors of independent walking at 30 months; an anatomical level of lesion below L2 at referral (aOR, 1.83 (95% CI, 1.30-2.58), P = 0.01) and female gender (aOR, 3.51 (95% CI, 1.43-8.61), P < 0.01) were also predictive for this outcome.

CONCLUSIONS

Prenatally repaired cases of ONTD have a better chance of being able to walk independently at 30 months than do those who undergo postnatal repair. In patients with prenatally repaired ONTD, ambulatory status at 30 months can be predicted by observing a low lesion level at referral (below L2) and intact motor function postnatally. These results have implications for parental counseling and planning for supportive therapy in pregnancies affected by ONTD. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

The value and limitations of using predetermined criteria in decision making for maternal-fetal interventions

Maternal-fetal interventions-such as prenatal fetal myelomeningocele (MMC) repair-are at the forefront of clinical innovation within maternal-fetal medicine, pediatric surgery, and neonatology. Many centers determine eligibility for innovative procedures using pre-determined inclusion and exclusion criteria based on seminal studies, for example, the "Management of Myelomeningocele Study" for prenatal MMC repair. What if a person's clinical presentation does not conform to predetermined criteria for maternal-fetal intervention? Does changing criteria on a case-by-case basis (i.e., ad hoc) constitute an innovation in practice and flexible personalized care or transgression of commonly held standards with potential negative consequences? We outline principle-based, bioethically justified answers to these questions using fetal MMC repair as an example. We pay special attention to the historical origins of inclusion and exclusion criteria, risks and benefits to the pregnant person and the fetus, and team dynamics. We include recommendations for maternal-fetal centers facing these questions.

Abnormal prenatal brain development in Chiari II malformation

Introduction

The Chiari II is a relatively common birth defect that is associated with open spinal abnormalities and is characterized by caudal migration of the posterior fossa contents through the foramen magnum. The pathophysiology of Chiari II is not entirely known, and the neurobiological substrate beyond posterior fossa findings remains unexplored. We aimed to identify brain regions altered in Chiari II fetuses between 17 and 26 GW.

Methods

We used in vivo structural T2-weighted MRIs of 31 fetuses (6 controls and 25 cases with Chiari II).

Results

The results of our study indicated altered development of diencephalon and proliferative zones (ventricular and subventricular zones) in fetuses with a Chiari II malformation compared to controls. Specifically, fetuses with Chiari II showed significantly smaller volumes of the diencephalon and significantly larger volumes of lateral ventricles and proliferative zones.

Discussion

We conclude that regional brain development should be taken into consideration when evaluating prenatal brain development in fetuses with Chiari II.

A comparison of MRI appearance and surgical detethering rates between intrauterine and postnatal myelomeningocele closures: a single-center pilot matched cohort study

INTRODUCTION

Intrauterine myelomeningocele repair (IUMR) and postnatal myelomeningocele repair (PNMR) differ in terms of both setting and surgical technique. A simplified technique in IUMR, in which a dural onlay is used followed by skin closure, has been adopted at our institution. The goal of this study was to compare the rates of clinical tethering in IUMR and PNMR patients, as well as to evaluate the appearance on MRI.

METHODS

We conducted a retrospective review of 36 patients with MMC repaired at our institution, with 2:1 PNMR to IUMR matching based on lesion level. A pediatric neuroradiologist blinded to the clinical details reviewed the patients' lumbar spine MRIs for the distance from neural tissue to skin and the presence or absence of a syrinx. An EMR review was then done to evaluate for detethering procedures and need for CSF diversion.

RESULTS

Mean age at MRI was 4.0 years and mean age at last follow-up was 6.1 years, with no significant difference between the PNMR and IUMR groups. There was no significant difference between groups in the distance from neural tissue to skin (PNMR 13.5 mm vs IUMR 17.6 mm; p = 0.5). There was no difference in need for detethering operations between groups (PNMR 12.5% vs IUMR 16.7%; RR 0.75; CI 0.1-5.1).

CONCLUSIONS

There was no significant difference between postnatal- and intrauterine-repaired myelomeningocele on MRI or in need for detethering operations. These results imply that a more straightforward and time-efficient IUMR closure technique does not lead to an increased rate of tethering when compared to the multilayered PNMR.

Long-term neurological cognitive, behavioral, functional, and quality of life outcomes after fetal myelomeningocele closure: a systematic review

BACKGROUND

Myelomeningocele is a lifelong condition that features several comorbidities, such as hydrocephalus, scoliosis, club foot, and lower limb sensory and motor disabilities. Its management has progressed over time, ranging from supportive care to early postnatal closure to prenatal closure of the defect. Recent research discovered that fetal myelomeningocele closure (fMMC) provided superior neurological outcomes to those of postnatal closure. When performed at 12 months of age, fMMC can avert or delay the need for a ventriculoperitoneal shunt and reversed the hindbrain herniation. Moreover, fMMC reportedly enhanced motor function and mental development at 30 months of age. However, its long-term outcomes remain dubious.

PURPOSE

This systematic review aimed to determine the long-term neurological cognitive, behavioral, functional, and quality of life (QoL) outcomes after fMMC.

METHODS

The PubMed, Directory of Open Access Journals, EBSCO, and Cochrane databases were extensively searched for articles published in 2007-2022. Meta-analyses, clinical trials, and randomized controlled trials with at least 5 years of follow-up were given priority.

RESULTS

A total of 11 studies were included. Most studies revealed enhanced long-term cognitive, behavioral, functional, and QoL outcomes after fMMC.

CONCLUSION

Our results suggest that fMMC substantially enhanced patients' long-term neurological cognitive, behavioral, functional, and QoL outcomes.

Fetal Surgery for Myelomeningocele: Neurosurgical Perspectives

More than 30 years have elapsed since it was recognised that folic acid supplementation could substantially reduce the risk of open neural tube defects (ONTDs). During that time, many countries have adopted policies of food fortification with demonstrable reduction in the incidence of both cranial and spinal ONTDs. Improved prenatal detection and termination has also resulted in a reduction in the number of affected live births. Nonetheless, in the USA about 1500 children, and in the UK around 500 children are born each year with myelomeningocele (MMC) and so the management of MMC and its complications continues to constitute a significant clinical workload for many paediatric neurosurgical units around the world.Until recently, the options available following antenatal diagnosis of MMC were termination of pregnancy or postnatal repair. As a result of the MOMS trial, prenatal repair has become an additional option in selected cases (Adzick et al., N Engl J Med 364(11):993-1004, 2011). Fetal surgery for myelomeningocele is now offered in more than 30 centres worldwide. The aim of this chapter is to review the experimental basis of prenatal repair of MMC, to critically evaluate the neurosurgical implications of this intervention and to describe the technique of 'open' repair, comparing this with emerging minimally invasive alternatives.

Disability or Death: A Focused Review of Informed Consent in Pediatric Neurosurgery

The management of pediatric neurosurgical disease often requires families to choose between long-term disability and premature death. This decision-making is codified by informed consent. In practice, decision-making is heavily weighted toward intervening to prevent death, often with less consideration of the realities of long-term disability. We analyze long-term disability in pediatric neurosurgical disease from the perspectives of patients, families, and society. We then present a pragmatic framework and conversational approach for addressing informed consent discussions when the outcome is expected to be death or disability. We performed a focused review of literature regarding informed consent in pediatric neurosurgery by searching PubMed and Google Scholar with search terms including "pediatric neurosurgery," "informed consent," and "disability." The literature was focused on patients with diagnoses including spina bifida, neuro-oncology, trauma, and hydrocephalus. Patient perspective elements were physical/mental disability, lack of autonomy, and role in community/society. The family perspective involves caregiver burden, emotional toll, and financial impact. Societal considerations include the availability of public resources for disabled children, large-scale financial cost, and impacts on global health. Practical conversational steps with patients/caregivers include opening the discussion, information provision and acknowledgement of uncertainty, assessment of understanding and clarifying questions, decision-making, and decision maintenance, all while remaining sensitive to the emotional burden commensurate with these decisions. The "death or disability" paradigm represents a common challenge to informed consent in pediatric neurosurgery. Patient, family, and societal factors that inform surrogate decisions vary and sometimes conflict. Pediatric neurosurgeons must use a comprehensive approach to address the informational and relational needs of caregivers during the informed consent process.

Fetal Repair of Neural Tube Defects

Myelomeningocele is the most common congenital neurologic defect, and the only nonlethal disease addressed by fetal surgery. A randomized control trial has established amelioration of the Arnold-Chiari II malformation, reduced ventriculoperitoneal shunt rate, and improvement in distal neurologic function in patients that receive in utero repair. Long-term follow-up of these school-age children demonstrates the persistence of these effects. The use of stem cells in fetal repair is being investigated to further improve distal motor function.

The Construction of a Predictive Composite Index for Decision-Making of CSF Diversion Surgery in Pediatric Patients following Prenatal Myelomeningocele Repair

BACKGROUND AND PURPOSE

There is a wide range of clinical and radiographic factors affecting individual surgeons' ultimate decision for CSF diversion for pediatric patients following prenatal myelomeningocele repair. Our aim was to construct a composite index (CSF diversion surgery index) that integrates conventional clinical measures and neuroimaging biomarkers to predict CSF diversion surgery in these pediatric patients.

MATERIALS AND METHODS

This was a secondary retrospective analysis of data from 33 patients with prenatal myelomeningocele repair (including 14 who ultimately required CSF diversion surgery). Potential independent variables, including the Management of Myelomeningocele Study Index (a dichotomized variable based on the shunt-placement criteria from the Management of Myelomeningocele Study), postnatal DTI measures (fractional anisotropy and mean diffusivity in the genu of the corpus callosum and the posterior limb of internal capsule), fronto-occipital horn ratio at the time of DTI, gestational ages, and sex, were evaluated using stepwise logistic regression analysis to identify the most important predictors.

RESULTS

The CSF diversion surgery index model showed that the Management of Myelomeningocele Study Index and fractional anisotropy in the genu of the corpus callosum were significant predictors (P < .05) of CSF diversion surgery. The predictive value of the CSF diversion surgery index was also affected by fractional anisotropy in the posterior limb of the internal capsule and sex with marginal effect (.05<P < .10), but not by the fronto-occipital horn ratio (P > .10). The overall CSF diversion surgery index model fit the data well with statistical significance (eg, likelihood ratio: P < .001), with the performance (sensitivity = 78.6%; specificity = 86.5%, overall accuracy = 84.8%) superior to all individual indices in sensitivity and overall accuracy, and most of the individual indices in specificity.

CONCLUSIONS

The CSF diversion surgery index model outperformed all single predictor models and, with additional validation, may potentially be developed and incorporated into a sensitive and robust clinical tool to assist clinicians in hydrocephalus management.

Early investigations into improving bowel and bladder function in fetal ovine myelomeningocele repair

INTRODUCTION

Fetal myelomeningocele (MMC) repair improves lower extremity motor function. We have previously demonstrated that augmentation of fetal MMC repair with placental mesenchymal stromal cells (PMSCs) seeded on extracellular matrix (PMSC-ECM) further improves motor function in the ovine model. However, little progress has been made in improving bowel and bladder function, with many patients suffering from neurogenic bowel and bladder. We hypothesized that fetal MMC repair with PMSC-ECM would also improve bowel and bladder function.

METHODS

MMC defects were surgically created in twelve ovine fetuses at median gestational age (GA) 73 days, followed by defect repair at GA101 with PMSC-ECM. Fetuses were delivered at GA141. Primary bladder function outcomes were voiding posture and void volumes. Primary bowel function outcome was anorectal manometry findings including resting anal pressure and presence of rectoanal inhibitory reflex (RAIR). Secondary outcomes were anorectal and bladder detrusor muscle thickness. PMSC-ECM lambs were compared to normal lambs (n = 3).

RESULTS

Eighty percent of PMSC-ECM lambs displayed normal voiding posture compared to 100% of normal lambs (p = 1). Void volumes were similar (PMSC-ECM 6.1 ml/kg vs. normal 8.8 ml/kg, p = 0.4). Resting mean anal pressures were similar between cohorts (27.0 mmHg PMSC-ECM vs. normal 23.5 mmHg, p = 0.57). RAIR was present in 3/5 PMSC-ECM lambs that underwent anorectal manometry and all normal lambs (p = 0.46). Thicknesses of anal sphincter complex, rectal wall muscles, and bladder detrusor muscles were similar between cohorts.

CONCLUSION

Ovine fetal MMC repair augmented with PMSC-ECM results in near-normal bowel and bladder function. Further work is needed to evaluate these outcomes in human patients.

Controversies in Fetal Surgery: Prenatal Repair of Myelomeningocele in the Modern Era

Fetal surgery is a constantly evolving field that showed noticeable progress with the treatment of myelomeningocele (MMC) using prenatal repair. Despite this success, there are ongoing questions regarding the optimal approach for fetal myelomeningocele repair, as well as which patients are eligible. Expansion of the inclusion and exclusion criteria is an important ongoing area of study for myelomeningocele including the recent Management of Myelomeningocele Plus trial. The significant personal and financial burden required of families seeking treatment has likely limited its accessibility to the general population.

Fetal open spinal dysraphism repair through a mini-hysterotomy: Influence of gestational age at surgery on children's ability to walk

OBJECTIVE

To analyze the impact of gestational age (GA) at the time of fetal open spinal dysraphism (OSD) repair through a mini-hysterotomy on the ability of children to walk.

METHODS

Children who underwent in utero repair of OSD and had formal neurological assessment after 2.5 years of age were compared regarding their ability to walk in relation to pre-surgical predictors.

RESULTS

Sixty-nine children fulfilled the inclusion criteria. Among them, 63.7% (44/69) were able to walk with or without orthesis. Fetal OSD correction performed earlier in gestation (from 19.7 to 26.9 weeks) was associated with a higher probability of walking with or without orthesis (p = 0.033). The median GA at delivery was 35.3 weeks. Multivariate binary logistic regression showed that the upper anatomical level of the OSD (<L4 or > L5) (p < 0.004; OR: 10.31 [95% CI: 2.07-51.28]) and GA at the time of fetal surgery (p = 0.026; OR = 0.68 [95% CI: 0.48-0.95]) were independent predictors of the postnatal ability to walk with or without orthesis.

CONCLUSION

Fetuses with OSD who were operated on earlier in pregnancy (range: 19.7-26.9 weeks), were more likely to walk with or without orthesis.

Impact of the cystic neural tube defects on fetal motor function in prenatal myelomeningocele repairs: A retrospective cohort study

OBJECTIVE

To determine the impact of the lesion type (cystic [myelomeningocele] or flat [myeloschisis]) on the fetal motor function (MF) in cases candidates for prenatal open neural tube defect (ONTD) repair.

METHODS

Retrospective cohort study of patients with ONTD who underwent prenatal repair at a single institution between 2011 and 2019. The lesion type and the measurements of the length and width of the lesions to calculate the surface of the ellipsoid lesion were performed using MR scans. Prenatal MF of the lower extremities was evaluated by ultrasound following a metameric distribution at the time of referral. Intact MF was defined as the observation of plantar flexion of the ankle. Logistic regression was performed to determine the predictive value of the type of lesion for having an intact MF at the time of referral.

RESULTS

103 patients were included at 22.9 (19-25.4) weeks; 65% had cystic and 35% had flat lesions. At the time of referral, there was a higher proportion of cases with an intact MF in the presence of flat lesions (34/36; 94.4%) as compared to cystic lesion (48/67; 71.6%, p < 0.01). When adjusting for gestational age and anatomical level of the lesion, flat ONTD were 3.1 times more likely to be associated by intact motor function (CI%95 [2.1-4.6], p < 0.01) at the time of referral.

CONCLUSION

Cystic ONTD are more likely to be associated with impaired MF at mid-gestation in candidates for prenatal ONTD repair.

Is ventriculomegaly and hindbrain herniation seen before and after prenatal neural tube defect repair associated with a worse functional level than anatomical level at birth?

OBJECTIVE

To determine if the evaluation of the fetal ventricular system and hindbrain herniation (HBH) is associated with motor outcome at birth in prenatally repaired open neural tube defect (NTD).

METHODS

Retrospective cohort study of 47 patients with NTD who underwent prenatal repair (17 fetoscopic; 30 open-hysterotomy). At referral and 6 weeks postoperatively, the degree of HBH, ventricular atrial widths and ventricular volume were evaluated by MRI. Head circumference and ventricular atrial widths were measured on ultrasound at referral and during the last ultrasound before delivery. Anatomic level of the lesion (LL) was determined based on the upper bony spinal defect detected by ultrasound. We considered the functional level as worse than anatomical level at birth when the motor level was equal or worse than the anatomical LL.

RESULTS

26% (12/47) of the cases showed worse functional level than anatomical level at birth. Having a HBH below C1 at the time of referral was associated with a worse functional level than anatomical level at birth (OR = 9.7, CI95 [2.2-42.8], p < 0.01). None of the other brain parameters showed a significant association with motor outcomes at birth.

CONCLUSIONS

HBH below C1 before surgery was associated with a worse functional level than anatomical level at birth.

Impact of the volume of the myelomeningocele sac on imaging, prenatal neurosurgery and motor outcomes: a retrospective cohort study

To investigate the association of the myelomeningocele (MMC) volume with prenatal and postnatal motor function (MF) in cases who underwent a prenatal repair. Retrospective cohort study (11/2011 to 03/2019) of 63 patients who underwent a prenatal MMC repair (37 fetoscopic, 26 open-hysterotomy). At referral, measurements of the volume of MMC was performed based on ultrasound scans. A large MMC was defined as greater than the optimal volume threshold (ROC analysis) for the prediction of intact MF at referral (2.7 cc). Prenatal or postnatal intact motor function (S1) was defined as the observation of plantar flexion of the ankle based on ultrasound scan or postnatal examination. 23/63 participants presented a large MMC. Large MMC lesions was associated with an increased risk of having clubfeet by 9.5 times (CI%95[2.1–41.8], p < 0.01), and reduces the chances of having an intact MF at referral by 0.19 times (CI%95[0.1–0.6], p < 0.01). At birth, a large MMC reduces the chance of having an intact MF by 0.09 times (CI%95[0.01–0.49], p < 0.01), and increases the risk of having clubfeet by 3.7 times (CI%95[0.8–18.3], p = 0.11). A lower proportion of intact MF and a higher proportion of clubfeet pre- or postnatally were observed in cases with a large MMC sac who underwent a prenatal repair.

Trial registration: Clinicaltrials.gov NCT02230072 and NCT03794011 registered on September 3rd, 2014 and January 4th, 2019.

[Prenatal ultrasound prognostic of myelomeningocele at the era of fetal surgery]

Myelomeningocele (MMC) is a severe congenital condition responsible for motor and sensory impairments of the lower limbs, incontinence and cognitive impairment. Its screening, sometimes as early as the first trimester, is one of the major goals of modern prenatal care, supported by the emergence of prenatal surgery that results in a significant improvement in motor function, ambulation and ventriculoperitoneal shunt rate in patients undergoing in-utero surgery. From screening to pre- and post-operative prognostic evaluation, prenatal ultrasound is now an essential tool in the antenatal management of this condition. Using the multi planar and three-dimensional modes, it can be used to assess the vertebral level of MMC, which remains the key antenatal prognostic marker for motor function and ambulation, incontinence and the need for a ventriculo-peritoneal shunt. A careful and systematic ultrasound examination also makes it possible to assess the severity and progression of ventriculomegaly, to search for associated cerebral, spinal cord or vertebral anomalies, or to rule out exclusion criteria for in-utero surgery such as severe kyphosis or serious cortical anomalies. New tools from post-natal evaluation, such as the "metameric" ultrasound assessment of lower limb mobility, appear to be promising either for the initial examination or after in-utero surgery. Ultrasonography, associated with fetal MRI, cytogenetic and next generation sequencing, now allows a highly customized prognostic evaluation of these fetuses affected by MMC and provides the parents with the best possible information on the expected benefits and limitations of fetal surgery.

Fetal myelomeningocele repair: a narrative review of the history, current controversies and future directions

Fetal surgery is a relatively new field of medicine. The purpose of this narrative review is to present the history of how fetal surgery became the standard of care for myelomeningocele (MMC), the current controversies of this treatment, and active areas of research that may change how MMC is treated. Fetal surgery for MMC emerged out of the University of California, San Francisco in the 1980s in the laboratory of Dr. Michael Harrison. Initial research focused on testing the hypothesis that the in utero repair of MMC could improve outcomes in the ovine model. Evidence from this model suggested that in utero repair decreases the secondary damage to the exposed neural tissue and improves post-natal neurologic outcomes, opening the door for human intervention. This was followed by the Management of Myelomeningocele Study (MOMS), which was a multicenter randomized controlled trial comparing the prenatal versus postnatal MMC repair. The MOMS trial was stopped early due to the improved outcomes of the prenatal repair, establishing the open fetal MMC repair as the standard of care. Since the MOMS trial, two primary areas of controversy have arisen: the operative approach and criteria for the repair. The three operative approaches include open, endoscopic and a hybrid approach combining open and endoscopic. Several of the inclusion and exclusion criteria from the MOMS trial have been challenged, to include body mass index, gestational diabetes, other fetal abnormalities, maternal infections and Rh alloimmunization. New areas of research have also emerged, exploring cell based therapies to improve fetal outcomes, alternatives to fetal surgery and alternatives to primary skin closure of the fetus.

Prenatal Repair and Physical Functioning Among Children With Myelomeningocele: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

The Management of Myelomeningocele Study (MOMS), a randomized clinical trial of prenatal vs standard postnatal repair for myelomeningocele, found that prenatal repair reduced hydrocephalus and hindbrain herniation and improved motor function in children aged 12 to 30 months. The Management of Myelomeningocele Study Follow-up (MOMS2) was conducted in children at ages 5 to 10 years. The primary (neurocognitive) outcome has already been reported.

OBJECTIVE

To determine whether MOMS2 participants who had prenatal repair have better physical functioning than those with postnatal repair.

DESIGN, SETTING, AND PARTICIPANTS

Participants from MOMS were recruited for participation in the follow-up study, MOMS2, conducted from April 9, 2012, to April 15, 2017. For this secondary analysis of the randomized clinical trial, trained examiners without knowledge of the treatment group evaluated the physical characteristics, self-care skills, neurologic function, and mobility of the children. Physical functioning outcomes were compared between the prenatal and postnatal repair groups. MOMS2 was conducted at the same 3 clinical sites as MOMS. Home visits were conducted for families who were unable to travel to one of the clinical sites. Of the 161 children with myelomeningocele aged 5 to 10 years old enrolled in MOMS2, 154 had a physical examination and were included in the analyses.

EXPOSURES

Prenatal repair of myelomeningocele.

MAIN OUTCOMES AND MEASURES

Prespecified secondary trial outcomes of self-care skills, functional mobility, walking skills, and motor level.

RESULTS

This analysis included 78 children with postnatal repair (mean [SD] age, 7.4 [2.1] years; 50 girls [64.1%]; 69 White children [88.5%]) and 76 with prenatal repair (mean [SD] age, 7.5 [1.2] years; 43 boys [56.6%]; 70 White children [92.1%]). Children in the prenatal repair group were more competent with self-care skills (mean [SD] percentage of maximum FRESNO Scale score, 90.8% [9.6%] vs 85.5% [17.6%]) and were commonly community ambulators per the Modified Hoffer Classification (51.3% prenatal vs 23.1% postnatal; adjusted relative risk [aRR] for sex, 1.70; 95% CI, 1.23-2.34). Children with prenatal repair also performed the 10-m walk test 1 second faster (difference in medians, 1.0; 95% CI, 0.3-1.7), had better gait quality (adjusted mean difference for home distances of 5 m, 1.71; 95% CI, 1.14-2.54), and could perform higher-level mobility skills (adjusted mean difference for motor total, 5.70; 95% CI, 1.97-11.18). Children in the prenatal repair group were less likely to have a motor function level worse than their anatomic lesion level (aRR, 0.44; 95% CI, 0.25-0.77).

CONCLUSIONS AND RELEVANCE

This secondary analysis of a randomized clinical trial found that the physical functioning benefits of prenatal repair for myelomeningocele reported at age 30 months persisted into school age. These findings indicate the benefit of prenatal repair of myelomeningocele for school-aged children.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00060606.

Fetal surgery for spina bifida in Zurich: results from 150 cases

PURPOSE

Over the past 10 years, over 150 fetal spina bifida surgeries were performed at the Zurich Center for Fetal Diagnosis and Therapy. This study looks at surrogates for success and failure of this approach.

METHODS

We focused on key outcome parameters including hydrocephalus shunt rate at one year, bladder control at 4, independent ambulation at 3 years, and maternal, fetal, and neonatal complications.

RESULTS

From the first 150 patients undergoing fetal surgery for spina bifida, 148 (98.7%) were included in the study. Maternal-fetal surgery was uneventful in 143/148 (97%) cases. Intraoperative problems included resuscitation in 4/148 fetuses (2.7%). 1/148 fetuses (0.7%) died on postoperative day 4. Maternal complications included chorioamniotic membrane separation in 22/148 (15%), lung embolism in 3/148 (2.1%), chorioamnionitis in 2/148 (1.4%), AV-block III and uterine rupture in 1/148 each (0.7%). 1/148 (0.7%) newborn death was recorded. Hindbrain herniation was identified preoperatively in 132/148 (90%) fetuses and resolved completely in 119/132 (90%). At one year, 39/106 (37%) children had required a CSF diversion. At 4 years, 4/34 patients (12%) had normal bladder control. At 3 years, 48/57 (84%) walked independently.

CONCLUSION

A majority of patients benefitted from prenatal intervention, in that the shunt rate was lower and the rates of continent and walking patients were higher than reported with postnatal care.

Comparison of Follow-Up Length-Matched Single-Center Myelomeningocele Postnatal Closure Cohort to the Management of Myelomeningocele Study (MOMS) Trial Results

OBJECTIVE

We sought to compare our large single-institution cohort of postnatal myelomeningocele closure to the 2 arms of the Management of Myelomeningocele Study (MOMS) trial at the designated trial time points, as well as assess outcomes at long-term follow-up among our postnatal cohort.

METHODS

A single-institutional retrospective review of myelomeningocele cases presenting from 1995 to 2015 at Children's Hospital of Pittsburgh was performed. We compared outcomes at 12 and 30 months to both arms of the MOMS trial and compared our cohort's outcomes at those designated time points to our long-term outcomes. Univariate statistical analysis was performed as appropriate.

RESULTS

One-hundred sixty-three patients were included in this study. All patients had at least 2-year follow-up, with a mean follow-up of 10 years (range 2-20 years). There was no difference in the overall distribution of anatomic level of defect. Compared to our cohort, the prenatal cohort had a higher rate of tethering at 12 months of age, 8 versus 1.8%. Conversely, the Chiari II decompression rate was higher in our cohort (10.4 vs. 1.0%). At 30 months, the prenatal cohort had a higher rate of independent ambulation, but our cohort demonstrated the highest rate of ambulation with or without assistive devices among the 3 groups. When comparing our cohort at these early time points to our long-term follow-up data, our cohort's ambulatory function decreased from 84 to 66%, and the rate of detethering surgery increased almost 10-fold.

CONCLUSIONS

This study demonstrated that overall ambulation and anatomic-functional level were significantly better among our large postnatal cohort, as well as having significantly fewer complications to both fetus and mother, when compared to the postnatal cohort of the MOMS trial. Our finding that ambulatory ability declined significantly with age in this patient population is worrisome for the long-term outcomes of the MOMS cohorts, especially given the high rates of cord tethering at early ages within the prenatal cohort. These findings suggest that the perceived benefits of prenatal closure over postnatal closure may not be as substantial as presented in the original trial, with the durability of results still remaining a concern.

Prenatal predictors of motor function in children with open spina bifida: a retrospective cohort study

OBJECTIVE

To identify predictors for intact motor function (MF) at birth and at 12 months of life in babies with prenatally versus postnatally repaired open spina bifida (OSB).

DESIGN

Retrospective cohort study.

SETTING

Texas Children's Hospital, 2011-2018.

POPULATION

Patients who underwent either prenatal or postnatal OSB repair.

METHODS

Prenatal MF of the lower extremities was evaluated by ultrasound following a metameric distribution at the time of diagnosis (US1), 6 weeks postoperatively (or 6 weeks after initial evaluation in postnatally repaired cases) (US2) and at the last ultrasound before delivery (US3). At birth and at 12 months, MF was assessed clinically. Intact MF (S1) was defined as the observation of plantar flexion of the ankle. Results from logistic regression analysis are expressed as odds ratios (95% confidence intervals, P values).

RESULTS

A total of 127 patients were included: 93 with prenatal repair (51 fetoscopic; 42 open hysterotomy repair) and 34 with postnatal repair. In the prenatal repair group, predictors for intact MF at birth and at 12 months included: absence of clubfeet (OR 11.3, 95% CI 3.2-39.1, P < 0.01; OR 10.8 95% CI 2.4-47.6, P < 0.01); intact MF at US1 (OR 19.7, 95% CI 5.0-76.9, P < 0.01; OR 8.7, 95% CI 2.0-38.7, P < 0.01); intact MF at US2 (OR 22, 95% CI 6.5-74.2, P < 0.01; OR 13.5, 95% 3.0-61.4, P < 0.01); intact MF at US3 (OR 13.7, 95% CI 3.4-55.9, P < 0.01; OR 12.6, 95% CI 2.5-64.3, P < 0.01); and having a flat lesion (OR 11.2, 95% CI 2.4-51.1, P < 0.01; OR 4.1, 95% CI 1.1-16.5, P = 0.04). In the postnatal repair group, the only predictor of intact MF at 12 months was having intact MF at birth (OR 15.2, 95% CI 2.0-113.3, P = 0.03).

CONCLUSIONS

The detection of intact MF in utero from mid-gestation to delivery predicts intact MF at birth and at 12 months in babies who undergo prenatal OSB repair.

TWEETABLE ABSTRACT

Detection of intact motor function in utero predicts intact motor function at birth and at 1 year in fetuses who undergo prenatal OSB repair.

Fetal spina bifida: What we tell the parents

Worldwide, about 150 000 infants are born with spina bifida yearly, making this condition one of the most common fetal central nervous system anomalies compatible with life. Over the last decade, major changes have been introduced in the prenatal diagnosis and management of spina bifida. In this review, we provide a brief summary of the current management of fetal spina bifida and present essential information that should be provided to expecting parents when their fetus has been diagnosed with spina bifida. This information is focused around common parental questions, as encountered in our typical clinical practice, to facilitate knowledge translation.

Hydrogel and neural progenitor cell delivery supports organotypic fetal spinal cord development in an ex vivo model of prenatal spina bifida repair

Studying how the fetal spinal cord regenerates in an ex vivo model of spina bifida repair may provide insights into the development of new tissue engineering treatment strategies to better optimize neurologic function in affected patients. Here, we developed hydrogel surgical patches designed for prenatal repair of myelomeningocele defects and demonstrated viability of both human and rat neural progenitor donor cells within this three-dimensional scaffold microenvironment. We then established an organotypic slice culture model using transverse lumbar spinal cord slices harvested from retinoic acid–exposed fetal rats to study the effect of fibrin hydrogel patches ex vivo. Based on histology, immunohistochemistry, gene expression, and enzyme-linked immunoabsorbent assays, these experiments demonstrate the biocompatibility of fibrin hydrogel patches on the fetal spinal cord and suggest this organotypic slice culture system as a useful platform for evaluating mechanisms of damage and repair in children with neural tube defects.

Impact of the size of the lesion in prenatal neural tube defect repair on imaging, neurosurgical and motor outcomes: a retrospective cohort study

OBJECTIVES

(1) To compare brain findings between large and non-large neural tube defect (NTD); (2) to evaluate the impact of large lesion on the surgical parameters; (3) to study any associations between the size of the lesions and brain findings 6 weeks postoperatively and neurological short-term outcomes.

DESIGN

Retrospective cohort study.

SETTING

Texas Children's Hospital, between 2011 and 2018.

POPULATION

Patients who underwent prenatal NTD repair.

METHODS

Large lesion was defined when the lesion's surface was >75th centile of our cohorts' lesions.

MAIN OUTCOME MEASURES

Time of referral: ventriculomegaly and anatomical level of the lesion; surgery: duration and need for relaxing incisions. 6 weeks postoperative: hindbrain herniation (HBH) and ventriculomegaly. After delivery: dehiscence, need for hydrocephalus treatment and motor function.

RESULTS

A total of 99 patients were included, 25 of whom presented with large lesions. Type of lesion and ventriculomegaly were comparable between individuals with large and non-large lesions. Individuals with large lesions were associated with increased need for relaxing incisions by 5.4 times (95% CI 1.3-23.2, P = 0.02). Six weeks postoperatively, having a large lesion decreased by ten times the likelihood of having a postoperative reversal of HBH (odds ratio = 0.1, 95% CI 0.1-0.4, P < 0.01). At birth, larger lesions increased the risk for repair dehiscence by 6.1 times (95% CI 1.6-22.5, P < 0.01) and the risk of dehiscence or leakage of cerebrospinal fluid at birth by 5.5 times (95% CI 1.6-18.9, P < 0.01).

CONCLUSION

Prenatal repair of patients with large NTD presents a lower proportion of HBH reversal 6 weeks after the surgery, a higher risk of dehiscence and a higher need for postnatal repair.

TWEETABLE ABSTRACT

Evaluation of the size of fetal NTD can predict adverse neurological outcomes after prenatal NTD repair.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on the Incidence of Tethered Cord Syndrome in Infants With Myelomeningocele With Prenatal Versus Postnatal Repair

BACKGROUND

The incidence of spina bifida (SB) is higher in the developing world as compared to the United States because of folic acid deficiency during pregnancy. Advances in technology have made prenatal repair of myelomeningocele (MM) possible.

OBJECTIVE

The objective of this guideline was to determine if there is a difference in the rate of development of tethered cord syndrome (TCS) in infants who had prenatal closure compared to infants who had MM repair after birth.

METHODS

The Guidelines Task Force developed search terms and strategies to search PubMed and Embase for the relevant literature published between 1966 and September 2016. Strict inclusion/exclusion criteria were used. Full text articles were reviewed and, when appropriate, included as evidence.

RESULTS

A total of 261 abstracts were reviewed. Fifty-four full-text articles were selected for further analysis. Three studies met inclusion criteria.

CONCLUSION

There was Class II evidence from 1 study and Class III evidence from another 2 studies demonstrating that TCS develops in infants with prenatal MM closure at an equal or higher rate than with postnatal closure. There was an increased risk of development of inclusion cysts in infants who underwent in utero closure. Continued surveillance for TCS and/or the development of inclusion cysts in children with prenatal and postnatal closure of MM is indicated (Level II). Differences between prenatal and postnatal repair with respect to the development of TCS and/or inclusion cysts should be considered alongside other relevant maternal and fetal outcomes when deciding upon a preferred method for MM closure.The full guideline can be found at https://www.cns.org/guidelines/guidelines-spina-bifida-chapter-6.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on the Management of Patients With Myelomeningocele: Whether Prenatal or Postnatal Closure Affects Future Ambulatory Status

BACKGROUND

Myelomeningocele (MM) is an open neural tube defect treated by pediatric neurosurgeons with prenatal or postnatal closure.

OBJECTIVE

The objective of this systematic review was to answer the question: What is the evidence for the effectiveness of prenatal vs postnatal closure of MM regarding short and long-term ambulatory status? Treatment recommendations were provided based on the available evidence.

METHODS

The National Library of Medicine PubMed database and Embase were queried using MeSH headings and keywords relevant to ambulatory status after prenatal or postnatal closure of MM. Abstracts were reviewed to identify which studies met the inclusion criteria. An evidence table was assembled summarizing the studies and the quality of evidence (Classes I-III). Based on the quality of the literature, a recommendation was rendered (Level I, II, or III).

RESULTS

One randomized controlled trial (Class II) and 3 retrospective cohort studies (Class III) were included as evidence. Initial ambulatory status depended on anatomic level of the neural tube defect. In the short term, prenatal closure may improve ambulatory status compared to postnatal closure. Spinal cord tethering or dermoid inclusion cyst has been associated with neurologic deterioration in infants closed in utero and after birth. Ambulation may cease in both groups over time. No long-term studies evaluated whether there is a difference in the ability to ambulate upon reaching adulthood.

CONCLUSION

Prenatal closure of MM may improve ambulatory status in the short term (Level II). Spinal cord tethering in both groups caused deterioration in the ability to walk. Evaluation and treatment of spinal cord tethering may help maintain ambulatory status (Level III). No studies evaluate whether prenatal or postnatal repair provides improved ability to ambulate upon reaching adulthood.The full guideline can be found at https://www.cns.org/guidelines/guidelines-spina-bifida-chapter-3.

Fetal surgical intervention for myelomeningocele: lessons learned, outcomes, and future implications

Fetal myelomeningocele (fMMC) closure (spina bifida aperta) has become a care option for patients that meet inclusion criteria, but it is clear that fetal intervention, while improving outcomes, is not a cure. This review will: (1) focus on the rationale for fMMC surgery based on preclinical studies and observations that laid the foundation for human pilot studies and a randomized controlled trial; (2) summarize important clinical outcomes; (3) discuss the feasibility, efficacy, and safety of recent developments in fetal surgical techniques and approaches; and (4) highlight future research directions. Given the increased risk of maternal and fetal morbidity associated with prenatal intervention, accompanied by the increasing number of centres performing interventions worldwide, teams involved in the care of these patients need to proceed with caution to maintain technical expertise, competency, and patient safety. Ongoing assessment of durability of the benefits of fMMC surgery, as well as additional refinement of patient selection criteria and counselling, is needed to further improve outcomes and reduce the risks to the mother and fetus. WHAT THIS PAPER ADDS: High-quality prospective studies are needed to broaden the indication for fetal surgery in the general myelomeningocele population. Innovative minimally invasive approaches have had promising results, yet lack comprehensive and robust experimental or clinical evaluation. Important information to help families make informed decisions regarding fetal surgery for myelomeningocele is provided.

Fetal open spinal dysraphism repair through a mini-hysterotomy: Influence of gestational age at surgery on the perinatal outcomes and postnatal shunt rates

OBJECTIVE

To analyze the impact of gestational age (GA) at the time of fetal open spinal dysraphism (OSD) repair through a mini-hysterotomy on the perinatal outcomes and the infants' ventriculoperitoneal shunt rates.

METHODS

Retrospective study of cases of fetal OSD correction performed from 2014 and 2019.

RESULTS

One hundred and ninety women underwent fetal surgery for OSD through a mini-hysterotomy, and 176 (176/190:92.6%) have since delivered. Fetal OSD correction performed earlier in the gestational period, ranging from 19.7 to 26.9 weeks, was associated with lower rates of postnatal ventriculoperitoneal shunting (P: .049). Earlier fetal surgeries were associated with shorter surgical times (P: .01), smaller hysterotomy lengths (P < .001), higher frequencies of hindbrain herniation reversal (P: .003), and longer latencies from surgery to delivery (P < .001). Median GA at delivery was 35.3 weeks. Multivariate binary logistic regression showed that both fetal lateral ventricle-to-hemisphere ratio (%; P < .001; OR: 1.14 [95% CI: 1.09-1.21]) and GA at the time of fetal surgery (P: .016; OR: 1.37 [95% CI: 1.07-1.77]) were independent predictors of postnatal ventriculoperitoneal shunting.

CONCLUSION

Fetuses with OSD who were operated on earlier in the gestational interval, which ranged from 19.7 to 26.9 weeks, were less prone to receiving postnatal ventriculoperitoneal shunts.

Towards Guideline-Based Management of Tethered Cord Syndrome in Spina Bifida: A Global Health Paradigm Shift in the Era of Prenatal Surgery

An estimated 60% of the world's population lives in Asia, where the incidence of neural tube defects is high. Aware that tethered cord syndrome (TCS) is an important comorbidity, the purpose of this systematic review was to explore the treatment of TCS among individuals living with spina bifida (SB) in Asia. MEDLINE and Embase databases were searched for relevant studies published from January 2000 to June 2018. Search terms such as 'spinal dysraphism,' 'spinabifida,' 'diastematomyelia,' 'lipomeningocele,' 'lypomyelomeningocele,' 'meningomyelocele,' and 'tethered cord syndrome' were used in diverse combinations. Of the 1,290 articles that were identified in accordance with PRISMA (Preferred Items for Systematic Reviews and Meta-Analyses) guidelines, 15 Asia-based studies met the inclusion criteria. Significant differences in the diagnostic criteria and management of TCS were documented. As the surgical techniques for prenatal closure of the spinal defect continue to evolve, their adoption internationally is likely to continue. In this setting, a clear and evidence-based approach to the definition and management of TCS is essential. The recent publication by the Spina Bifida Association of America of their updated care guidelines may serve as a tool used to promote a systematized approach to diagnosing and treating TCS among individuals with SB in the region, as well as globally.

EAU/ESPU guidelines on the management of neurogenic bladder in children and adolescent part I diagnostics and conservative treatment

BACKGROUND

In childhood, the most common reason for a neurogenic bladder is related to spinal dysraphism, mostly myelodysplasia.

AIMS

Herein, we present the EAU/ESPU guidelines in respect to the diagnostics, timetable for investigations and conservative management including clean intermittent catheterization (CIC).

MATERIAL AND METHODS

After a systematic literature review covering the period 2000 to 2017, the ESPU/EUAU guideline for neurogenic bladder underwent an update.

RESULTS

The EAU/ESPU guideline panel advocates a proactive approach. In newborns with spina bifida, CIC should be started as soon as possible after birth. In those with intrauterine closure of the defect, urodynamic studies are recommended be performed before the patient leaves the hospital. In those with closure after birth urodynamics should be done within the next 3 months. Anticholinergic medication (oxybutynin is the only well-investigated drug in this age group-dosage 0.2-0.4 mg/kg weight per day) should be applied, if the urodynamic study confirmed detrusor overactivity. Close follow-up including ultrasound, bladder diary, urinalysis, and urodynamics are necessary within the first 6 years and after that the time intervals can be prolonged, depending on the individual risk and clinical course. In all other children with the suspicion of a neurogenic bladder due to various reasons as tethered cord, inflammation, tumors, trauma, or other reasons as well as those with anorectal malformations, urodynamics-preferable video-urodynamics, should be carried out as soon as there is a suspicion of a neurogenic bladder and conservative treatment should be started soon after confirmation of the diagnosis of neurogenic bladder. With conservative treatment the upper urinary tract is preserved in up to 90%, urinary tract infections are common, but not severe, complications of CIC are quite rare and continence can be achieved at adolescence in up to 80% without further treatment.

DISCUSSION AND CONCLUSIONS

The transition into adulthood is a complicated time for both patients, their caregivers and doctors, as the patient wants to become independent from caregivers and treatment compliance is reduced. Also, transition to adult clinics for patients with neurogenic bladders is often not well-established.

Fetal surgery for open spina bifida

KEY CONTENT

Spina bifida is a congenital neurological condition with lifelong physical and mental effects.Open fetal repair of the spinal lesion has been shown to improve hindbrain herniation, ventriculoperitoneal shunting, independent mobility and bladder outcomes for the child and, despite an increased risk of prematurity, does not seem to increase the risk of neurodevelopmental impairment.Open fetal surgery is associated with maternal morbidity.Surgery at our institution is offered and performed according to internationally agreed criteria and protocols.Further evidence regarding long-term outcomes, fetoscopic repair and alternative techniques is awaited.

LEARNING OBJECTIVES

To understand the clinical effects, potential prevention and prenatal diagnosis of spina bifida.To understand the rationale and evidence supporting the benefits and risks of fetal repair of open spina bifida.To understand the criteria defining those who are likely to benefit from fetal surgery.

ETHICAL ISSUES

The concept of the fetus as a patient, and issues surrounding fetal death or the need for resuscitation during fetal surgery.The associated maternal morbidity in a procedure performed solely for the benefit of the fetus/child.The financial implications of new surgical treatments.

Fetal myelomeningocele repair

Myelomeningocele is a congenital malformation that causes a spectrum of morbidity. With the standard of care now being in utero repair, the spectrum of morbidity has changed. The purpose of this article is to review the diagnosis, workup and treatment options of fetal myelomeningocele. We also review the obstetrical, neurological, gastrointestinal, urinary, and orthopedic outcomes of the in utero myelomeningocele repair.

Fetal surgery for spina bifida

The two-hit hypothesis of neural injury in the wake of open neural tube defects suggests an opportunity for preservation of function and potential reversibility of early morphological changes in the fetus diagnosed with myelomeningocele. The Management of Myelomeningocele Study (MOMS) demonstrated reduced need for shunting and improved neurological function in patients treated in utero relative to postnatally, thereby offering level 1 evidence supporting fetal repair. Subsequent studies have offered additional information about urological, orthopedic, radiological, and maternal factors surrounding fetal repair. The quest for robust long-term neurocognitive and motor function data is underway and poised to shape the future of fetal repair. In addition, technical innovations such as fetoscopic surgery aim to minimize maternal morbidity while conferring the beneficial effects observed with open intrauterine intervention.

Low level myelomeningoceles: do they need prenatal surgery?

BACKGROUND

Postnatal closure of a myelomeningocele remains the standard of care in many countries. The prenatal closure has given hope for decreasing the damage to the neural placode and has challenged classic management. However, this technique presents potential sources of complications. Patients with MMC with an anatomical level of L4 and below have a better functional prognosis than higher level malformations. Are they still candidates for prenatal surgery?

OBJECTIVE

To evaluate outcome of MMC with an anatomical level of L4 and below and discuss, with support of the literature, the indications to perform prenatal closure in this particular group of patients.

MATERIALS AND METHODS

Twenty-nine children were included in this observational study. The level of the vertebral malformation was sacral in 12 cases (41.4%) or lumbar (level ≤ L4) in 17 cases (58.6%). All the patients was operated postnatally for closure of the MMC with microsurgical technique as soon as possible after clinical evaluation (range 0-97 days).

RESULTS

Only 11 out of 29 patients (37.9%) needed of a CSF diversion. A Chiari II malformation was present before MMC closure in 17 patients (58.6%) and only in 5 (17%) after. Twenty-six patients (89.7%) were able to walk. Seven (23%) and 16 (55%) of our patients have a normal bladder and bowel control, respectively. All school-aged children attend school.

CONCLUSIONS

The functional outcome for low-level MMC is good when managed with modern microneurosurgical techniques with a low risk for the patient and the mother. Therefore, we do not suggest prenatal surgery for subgroup of infant with MM.

Neurodevelopmental outcome of children with spina bifida aperta repaired prenatally vs postnatally: systematic review and meta-analysis

OBJECTIVE

To assess the neurodevelopmental outcome of children with spina bifida aperta (SBA) treated prenatally as compared to those treated postnatally.

METHODS

We performed a systematic review of the literature in PubMed/MEDLINE, EMBASE, Web of Science and The Cochrane Library, comparing the neurological outcome of infants with SBA treated prenatally vs postnatally. Only randomized controlled trials (RCTs) and non-randomized prospective controlled studies were included. The primary outcome assessed was neurodevelopmental impairment at the age of 1 year or later. Secondary outcomes were preterm birth, need for ventriculoperitoneal (VP) shunt by 12 months of age, absence of signs of hindbrain herniation at the first postnatal magnetic resonance imaging (MRI) evaluation and independent ambulation evaluated at 30 months.

RESULTS

Of 11 359 studies identified through the electronic search, six met the inclusion criteria and were assessed in full text and two, one RCT and one prospective cohort study, were ultimately included in the meta-analysis. Sensitivity analysis did not show any difference between the outcomes of the RCT alone and those of the pooled RCT and prospective cohort study. This allowed neurodevelopmental assessment of 213 children between 14 and 53 months of age. Neurodevelopment was assessed by the Bayley Scales of Infant Development II (BSID-II) mental development index corrected for chronological age, with a cut-off of ≥ 70 (representing no more than 2 SD below the mean). The presence of neurodevelopmental impairment was similar between children who underwent prenatal (25/105 (23.8%)) and those who had postnatal (30/108 (27.8%)) repair of SBA (odds ratio (OR), 0.82 (95% CI, 0.43-1.56); P = 0.54), although the risk of prematurity was higher in the prenatal-repair group (OR, 17.62 (95% CI, 7.60-40.87); P < 0.0001). For every two fetuses operated on before birth, there was, compared with those operated on after birth, one additional premature birth (number needed to harm = 2 (95% CI, 1-3)). The need for VP shunt placement by 12 months of age was lower in the prenatal-repair group (45/109 (41.3%)) than in children that had postnatal repair (93/112 (83.0%); OR, 0.14 (95% CI, 0.08-0.26); P < 0.0001). Data on neurodevelopmental impairment in children with a shunt were available only for patients from the prenatal-surgery group of the RCT; in this subgroup, the likelihood for impairment was similar between children who did (7/39 (17.9%)) and those who did not (4/48 (8.3%)) have shunt placement (P = 0.21). At first postnatal MRI evaluation, no signs of hindbrain herniation were detected in 28/88 (31.8%) children who were operated on prenatally compared with 4/89 (4.5%) who had postnatal repair (OR, 9.45 (95% CI, 3.12-28.64); P < 0.0001). Independent ambulation at 30 months was achieved by 41/109 (37.6%) children who underwent prenatal repair compared with 21/111 (18.9%) who had postnatal repair (OR, 2.59 (95% CI, 1.39-4.86); P = 0.003).

CONCLUSION

The risk of neurodevelopmental impairment in infants with SBA was similar between those who underwent prenatal and those who had postnatal surgical repair, despite an increased risk of prematurity in the prenatally repaired group. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Fetal surgery for spina bifida aperta

Spina bifida aperta (SBA) is one of the most common congenital malformations. It can cause severe lifelong physical and neurodevelopmental disabilities. Experimental and clinical studies have shown that the neurological deficits associated with SBA are not simply caused by incomplete neurulation at the level of the lesion. Additional damage is caused by prolonged exposure of the spinal cord and nerves to the intrauterine environment and a suction gradient due to cerebrospinal fluid leakage, leading to progressive downward displacement of the hindbrain. This natural history can be reversed by prenatal repair. A randomised controlled trial demonstrated that mid-gestational maternal-fetal surgery for SBA decreases the need for ventriculoperitoneal shunting and hindbrain herniation at 12 months and improves neurological motor function at 30 months of age. This came at the price of maternal and fetal risks, the most relevant ones being increased prematurity and a persistent uterine corporeal scar. Recently minimally invasive fetal approaches have been introduced clinically yet they lack extensive experimental or clinical trials. We aim to provide clinicians with the essential information necessary to counsel SBA parents as the basis for considering referral of selected patients to expert fetal surgery centres. We review the reported clinical outcomes and discuss recent developments of potentially less invasive fetal SBA approaches.

Amniotic fluid transcriptomics reflects novel disease mechanisms in fetuses with myelomeningocele

BACKGROUND

Cell-free RNA in amniotic fluid supernatant reflects developmental changes in gene expression in the living fetus, which includes genes that are specific to the central nervous system. Although it has been previously shown that central nervous system-specific transcripts are present in amniotic fluid supernatant, it is not known whether changes in the amniotic fluid supernatant transcriptome reflect the specific pathophysiologic condition of fetal central nervous system disorders. In myelomeningocele, there is open communication between the central nervous system and amniotic fluid.

OBJECTIVES

The purpose of this study was to identify molecular pathophysiologic changes and novel disease mechanisms that are specific to myelomeningocele by the analysis of amniotic fluid supernatant cell-free RNA in fetuses with open myelomeningocele.

STUDY DESIGN

Amniotic fluid supernatant was collected from 10 pregnant women at the time of the open myelomeningocele repair in the second trimester (24.5±1.0 weeks); 10 archived amniotic fluid supernatant from sex and gestational age-matched euploid fetuses without myelomeningocele were used as controls (20.9±0.9 weeks). Differentially regulated gene expression patterns were analyzed with the use of human genome expression arrays.

RESULTS

Fetuses with myelomeningocele had 284 differentially regulated genes (176 up- and 108 down-regulated) in amniotic fluid supernatant. Known genes that were associated with myelomeningocele (PRICKLE2, GLI3, RAB23, HES1, FOLR1) and novel dysregulated genes were identified in association with neurodevelopment and neuronal regeneration (up-regulated, GAP43 and ZEB1) or axonal growth and guidance (down-regulated, ACAP1). Pathway analysis demonstrated a significant contribution of inflammation to disease and a broad influence of Wnt signaling pathways (Wnt1, Wnt5A, ITPR1).

CONCLUSION

Transcriptomic analyses of living fetuses with myelomeningocele with the use of amniotic fluid supernatant cell-free RNA demonstrated differential regulation of specific genes and molecular pathways relevant to this central nervous system disorder, which resulted in a new understanding of pathophysiologic changes. The data also suggested the importance of pathways that involve secondary disease, such as inflammation, in myelomeningocele. These newly identified pathways may lead to hypotheses that can test novel therapeutic targets as adjuncts to fetal surgical repair.

Prenatal surgery for myelomeningocele: review of the literature and future directions

Open spina bifida or myelomeningocele (MMC) is one of the most common serious congenital malformations. Historically, this condition has been treated with closure of the MMC defect shortly after birth. The goal of postnatal closure is to cover the exposed spinal cord and prevent infection. However, postnatal surgery does not reverse or prevent the neurologic injury seen in MMC, reverse hindbrain herniation, or prevent hydrocephalus. The neurologic defects result from primary incomplete neurulation and secondary chronic prenatal damage to the exposed neural elements through mechanical and chemical trauma. In a hope to reduce the numerous surgical procedures, medical complications, and lifelong disabilities associated with MMC, the proposal of prenatal closure was put forth more than two decades ago. After promising results in animal models and some clinical series, a randomized controlled trial, the Management of Myelomeningocele Study (MOMS), was conducted. The MOMS trial demonstrated that closure during the prenatal period could be performed relatively safely and can result in significant benefit to the child. Specifically, prenatal closure results in improved motor function, reduced hindbrain herniation, and reduced need for a cerebral spinal fluid diversion. Long-term outcomes of the patients in the MOMS trial continues in the MOMS 2 study as these children grow. Additionally, investigations are underway on modifications to the open fetal MMC closure techniques.

New directions in fetal surgery for myelomeningocele

The treatment of children with myelomeningocele (MMC) has improved over time, from supportive management to early postnatal closure to prenatal repair of the defect. The Management of Myelomeningocele Study (MOMS) showed that prenatal repair of MMC resulted in improved neurological outcomes compared to postnatal closure. Follow-up studies showed that prenatal repair was, as with any other fetal intervention, associated with higher rates of obstetrical complications. There was no significant difference in urological outcomes. Long-term follow-up of ambulatory status, executive functioning, and urological outcomes is needed to determine the durable effects of fetal MMC repair on mobility, functional independence, and the prevalence of renal insufficiency in patients with MMC who survive to adulthood. The future of fetal MMC repair consists of developing strategies to reduce maternal morbidity and improve infant outcomes. Fetoscopic MMC repair has been suggested as an alternative to open repair that may reduce obstetrical complications and the need for cesarean delivery in subsequent pregnancies. Translational research using mesenchymal stromal cells to augment fetal repair of ovine MMC has shown improvement in motor function.

Anesthesia for fetal surgery

Fetal therapy is an exciting and growing field of medicine. Advances in prenatal imaging and continued innovations in surgical and anesthetic techniques have resulted in a wide range of fetal interventions including minimally invasive, open mid-gestation, and ex-utero intrapartum treatment procedures. The potential for maternal morbidity is significant and must be carefully weighed against claimed benefits to the fetus. Appropriate patient selection is critical, and a multidisciplinary team-based approach is strongly recommended. The anesthetic management should focus on maintaining uteroplacental circulation, achieving profound uterine relaxation, optimizing surgical conditions, monitoring fetal hemodynamics, and minimizing maternal and fetal risk.

Surrogate Pregnancy After Prenatal Diagnosis of Spina Bifida

Some pregnancies today involve infertile individuals or couples who contract with a fertile woman to carry a pregnancy for them. The woman who carries the pregnancy is referred to as a "gestational carrier." The use of such arrangements is increasing. Most of the time, these arrangements play out as planned; sometimes, however, problems arise. This article discusses a case in which a fetal diagnosis of spina bifida led the infertile couple to request that the gestational carrier terminate the pregnancy, and the gestational carrier did not wish to do so. Experts in the medical and legal issues surrounding surrogacy discuss the considerations that should go into resolving such a conflict.

Outcomes of infants followed-up at least 12 months after fetal open and endoscopic surgery for meningomyelocele: a systematic review and meta-analysis

OBJECTIVE

To assess the outcomes of infants followed-up at least 12 months after open and endoscopic fetal surgery for the treatment of spina bifida.

METHODS

A searching in The Cochrane Library, LILACS, PubMed and SCOPUS databases for fetal meningomyelocele (MMC) open or endoscopic surgery in humans from 2003 on-wards with follow-up at least 12 months. The rate of the estimated proportions was evaluated by the 95% confidence interval (CI).

RESULTS

A total of 19 studies were finally included (17 open and 2 endoscopic surgery). The results suggested that the rate for ventriculoperitoneal shunt placement were 40% (29%, 51%) versus 45% (34%, 56%) for open surgery group and endoscopic surgery group. The rate of hindbrain herniation reversal was 34% (28%, 52%) versus 86% (49%, 97%), the lower extremity function rates for both groups were 47% (30%, 64%) versus 86% (49%, 97%), and bladder dysfunction rates for both groups were 72% (53%, 88%) versus 29% (8%, 64%), respectively. Open and endoscopic fetal surgery for MMC presented similar ventriculoperitoneal shunt rates.

CONCLUSION

Open and endoscopic fetal surgery for MMC presented similar ventriculoperitoneal shunt rates in infants followed at least 12 months.