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

Effect of Photobiomodulation Combined with Physiotherapy on Functional Performance in Children with Myelomeningo-Cele-Randomized, Blind, Clinical Trial

BACKGROUND

This study aimed to evaluate the electrical activity of the rectus femoris, tibialis anterior, and lateral gastrocnemius muscles during the sit-to-stand task and functional mobility after a neurofunctional physiotherapy protocol associated with PBM.

METHODS

Twenty-five children were randomly allocated to either Active PBM + physiotherapy (n = 13) or PBM sham + physiotherapy (n = 12). PBM was carried out with a LED device (850 nm, 25 J, 50 s per point and 200 mW) at four points over the area with absence of a spiny process. Both groups completed a twelve-week supervised program with two weekly 45-60 min sessions. Pre-training and post-training assessments involved the Pediatric Evaluation of Disability Inventory (PEDI). Muscle activity was assessed using portable electromyography (BTS Engineering) and the electrodes were positioned on the lateral gastrocnemius, anterior tibialis, and rectus femoris muscles. The RMS data were recorded and analyzed.

RESULTS

After 24 sessions of the treatment protocol, improvements were found in the PEDI score. The participants presented greater independence in performing the tasks, requiring less assistance from their caregivers. More significant electrical activity was found in the three muscles evaluated between the rest period and execution of the sit-to-stand tasks, both in the more compromised or less compromised lower limbs.

CONCLUSION

Neurofunctional physiotherapy with or without PBM improved functional mobility and electrical muscle activity in children with myelomeningocele.

Neurologic Outcome Comparison between Fetal Open-, Endoscopic- and Neonatal-Intervention Techniques in Spina Bifida Aperta

INTRODUCTION

In spina bifida aperta (SBA), fetal closure of the myelomeningocele (MMC) can have a neuroprotective effect and improve outcomes. In Europe, surgical MMC closure is offered by fetal-open (OSBAR), fetal-endoscopic (FSBAR), and neonatal (NSBAR) surgical techniques. Pediatric neurologists facing the challenging task of counseling the parents may therefore seek objective outcome comparisons. Until now, such data are hardly available. In SBA, we aimed to compare neurologic outcomes between OSBAR, FSBAR, and NSBAR intervention techniques.

METHODS

We determined intervention-related complications, neuromuscular integrity, and neurologic outcome parameters after OSBAR (n = 17) and FSBAR (n = 13) interventions by age- and lesion-matched comparisons with NSBAR-controls. Neurological outcome parameters concerned: shunt dependency, segmental alterations in muscle ultrasound density (reflecting neuromuscular integrity), segmental motor-, sensory- and reflex conditions, and the likelihood of intervention-related gain in ambulation.

RESULTS

Compared with NSBAR-controls, fetal intervention is associated with improved neuromuscular tissue integrity, segmental neurological outcomes, reduced shunt dependency, and a higher chance of acquiring ambulation in ≈20% of the operated children. Children with MMC-lesions with a cranial border at L3 revealed the most likely intervention-related motor function gain. The outcome comparison between OSBAR versus FSBAR interventions revealed no significant differences.

CONCLUSION

In SBA, OSBAR- and FSBAR-techniques achieved similar neuroprotective results. A randomized controlled trial is helpful in revealing and compare ongoing effects by surgical learning curves.

Natural history of posterior fetal cephaloceles and incidence of progressive cephalocele herniation

OBJECTIVE

In utero repair of fetal posterior cephaloceles (meningocele and encephalocele) is being performed based on the premise that fetal surgery prevents progressive herniation of neural tissue and brain damage during pregnancy. However, the extent to which progressive herniation occurs during pregnancy, specifically from prenatal diagnosis to after delivery, is not well known. The objective of this study was to describe the natural history of patients with fetal cephaloceles focusing on the incidence of progressive herniation.

METHODS

The authors conducted a retrospective cohort study of all patients referred to their center for posterior fetal cephalocele between 2006 and 2021. All patients underwent prenatal and postnatal MRI. Progressive herniation (primary outcome) was defined as an increase in the absolute volume of neural tissue within the cephalocele of > 5% or new herniation of a critical structure into the cephalocele. Total brain and cephalocele volumes were calculated to determine herniation progression from prenatal to postnatal MRI. Information on the presence of hydrocephalus, epilepsy, and developmental delay (secondary outcomes) was collected at 1 year of age.

RESULTS

Twenty patients met all study criteria. Ten patients (50%; 95% CI 0.27-0.73) demonstrated progressive herniation from prenatal to postnatal MRI. Three patients with progressive herniation were diagnosed with a meningocele prenatally and had an encephalocele postnatally. Two patients without progression had meningocele identified prenatally that regressed and became atretic by birth. Both prenatal hindbrain herniation (p = 0.03) and prenatal microcephaly (p = 0.05) were predictive of progressive herniation. The rates of hydrocephalus (44%), epilepsy (44%), and developmental delay (63%) were not associated with the occurrence of progressive herniation in this study.

CONCLUSIONS

In this study, progressive herniation was not a rare event (50%). Fetal hindbrain herniation and fetal microcephaly were associated with the occurrence of progressive herniation. These results support further investigations into why progressive herniation occurs in utero and if progressive cerebral herniation in utero plays a significant role in determining clinical outcome.

A spatio-temporal atlas of the developing fetal brain with spina bifida aperta

Background: Spina bifida aperta (SBA) is a birth defect associated with severe anatomical changes in the developing fetal brain. Brain magnetic resonance imaging (MRI) atlases are popular tools for studying neuropathology in the brain anatomy, but previous fetal brain MRI atlases have focused on the normal fetal brain. We aimed to develop a spatio-temporal fetal brain MRI atlas for SBA. Methods: We developed a semi-automatic computational method to compute the first spatio-temporal fetal brain MRI atlas for SBA. We used 90 MRIs of fetuses with SBA with gestational ages ranging from 21 to 35 weeks. Isotropic and motion-free 3D reconstructed MRIs were obtained for all the examinations. We propose a protocol for the annotation of anatomical landmarks in brain 3D MRI of fetuses with SBA with the aim of making spatial alignment of abnormal fetal brain MRIs more robust. In addition, we propose a weighted generalized Procrustes method based on the anatomical landmarks for the initialization of the atlas. The proposed weighted generalized Procrustes can handle temporal regularization and missing annotations. After initialization, the atlas is refined iteratively using non-linear image registration based on the image intensity and the anatomical land-marks. A semi-automatic method is used to obtain a parcellation of our fetal brain atlas into eight tissue types: white matter, ventricular system, cerebellum, extra-axial cerebrospinal fluid, cortical gray matter, deep gray matter, brainstem, and corpus callosum. Results: An intra-rater variability analysis suggests that the seven anatomical land-marks are sufficiently reliable. We find that the proposed atlas outperforms a normal fetal brain atlas for the automatic segmentation of brain 3D MRI of fetuses with SBA. Conclusions: We make publicly available a spatio-temporal fetal brain MRI atlas for SBA, available here:  https://doi.org/10.7303/syn25887675. This atlas can support future research on automatic segmentation methods for brain 3D MRI of fetuses with SBA.

The Role of Fetal Brain Magnetic Resonance Imaging in Current Fetal Medicine

In open spina bifida we studied the use of MRI for the assessment of the posterior fossa and prevalence of supratentorial anomalies before and after in utero repair. New postprocessing techniques were applied to evaluate fetal brain development in this population compared to controls. In fetuses with congenital diaphragmatic hernia, we evaluated the brain development in comparison to controls. Diffusion weighted imaging was applied to study difference between fetuses with proven first trimester cytomegalovirus infection and controls. Finally, we investigated the value of third trimester fetal brain MRI after treatment for complicated monochorionic diamniotic pregnancies.

Complex gastroschisis: a new indication for fetal surgery?

Gastroschisis (GS) is a congenital abdominal wall defect, in which the bowel eviscerates from the abdominal cavity. It is a non-lethal isolated anomaly and its pathogenesis is hypothesized to occur as a result of two hits: primary rupture of the 'physiological' umbilical hernia (congenital anomaly) followed by progressive damage of the eviscerated bowel (secondary injury). The second hit is thought to be caused by a combination of mesenteric ischemia from constriction in the abdominal wall defect and prolonged amniotic fluid exposure with resultant inflammatory damage, which eventually leads to bowel dysfunction and complications. GS can be classified as either simple or complex, with the latter being complicated by a combination of intestinal atresia, stenosis, perforation, volvulus and/or necrosis. Complex GS requires multiple neonatal surgeries and is associated with significantly greater postnatal morbidity and mortality than is simple GS. The intrauterine reduction of the eviscerated bowel before irreversible damage occurs and subsequent defect closure may diminish or potentially prevent the bowel damage and other fetal and neonatal complications associated with this condition. Serial prenatal amnioexchange has been studied in cases with GS as a potential intervention but never adopted because of its unproven benefit in terms of survival and bowel and lung function. We believe that recent advances in prenatal diagnosis and fetoscopic surgery justify reconsideration of the antenatal management of complex GS under the rubric of the criteria for fetal surgery established by the International Fetal Medicine and Surgery Society (IFMSS). Herein, we discuss how conditions for fetoscopic repair of complex GS might be favorable according to the IFMSS criteria, including an established natural history, an accurate prenatal diagnosis, absence of fully effective perinatal treatment due to prolonged need for neonatal intensive care, experimental evidence for fetoscopic repair and maternal and fetal safety of fetoscopy in expert fetal centers. Finally, we propose a research agenda that will help overcome barriers to progress and provide a pathway toward clinical implementation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Neurosurgical procedures for children with myelomeningocele after fetal or postnatal surgery: a comparative effectiveness study

AIM

To compare the frequencies of neurosurgical procedures to treat comorbid conditions of myelomeningocele in patients who underwent fetal surgery versus postnatal surgery for closure of the placode.

METHOD

By utilizing the National Spina Bifida Patient Registry in a comparative effectiveness study, 298 fetal surgery patients were matched by birthdate (±3mo) and spina bifida clinic site with one to three postnatal surgery patients (n=648). Histories were obtained by record review on enrollment and yearly subsequently. Multivariable Poisson regression was used to compare frequencies of procedures between cohorts, with adjustments for sex, ethnicity, insurance status, spinal segmental level of motor function, age at last visit recorded in the Registry, and, for shunt revision in shunted patients, age at cerebrospinal fluid (CSF) diversion.

RESULTS

The median age at last visit was 4 years. In fully adjusted analyses in patients aged at least 12 months old, fetal surgery was associated with decreased frequency of CSF diversion for hydrocephalus by ventriculoperitoneal shunt insertion or endoscopic third ventriculostomy compared with postnatal surgery (46% vs 79%; incidence rate ratio=0.61; 95% confidence interval [CI] 0.53-0.71; p<0.01). Over all ages, fetal surgery was associated with decreased frequency of Chiari decompression for brainstem dysfunction (3% vs 7%; incidence rate ratio=0.41; 95% CI 0.19-0.88; p=0.02). Also over all ages, differences were not significant in frequencies of shunt revision in shunted patients (53% vs 55%; incidence rate ratio=0.87; 95% CI 0.69-1.11; p=0.27), nor tethered cord release for acquired spinal cord dysfunction (18% vs 16%; incidence rate ratio=1.11; 95% CI 0.84-1.47; p=0.46).

INTERPRETATION

Even with the variations inherent in clinical practice, fetal surgery was associated with lower frequencies of CSF diversion and of Chiari decompression, independent of covariates. What this paper adds Fetal surgery was associated with lower frequencies of cerebrospinal fluid diversion and decompression of Chiari II malformation than postnatal surgery. Frequencies of ventriculoperitoneal shunt revision and tethered cord release were not significantly different between cohorts.

Preliminary Results of a Reverse Thermal Gel Patch for Fetal Ovine Myelomeningocele Repair

BACKGROUND

Prenatal surgical closure of Myelomeningocele (MMC) is considered part of the current age armamentarium. Clinical data has demonstrated the need for innovative patches to maximize the benefits and decrease the risks of this approach. Our team has developed a minimally invasive reverse thermal gel (RTG) patch with cellular scaffolding properties. Here, we demonstrate the initial gross and microscopic histological effects of this RTG patch in the fetal ovine model of MMC.

MATERIALS AND METHODS

A fetal ovine MMC defect was created at 68-75 days gestation, RTG patch application or untreated at 100-103 days, and harvest at 135-140 days. The RTG was applied to the defect and secured in place with an overlay sealant. Defect areas underwent gross and microscopic analysis for inflammation and skin development. Brains were analyzed for hindbrain herniation and hydrocephalus.

RESULTS

The untreated fetus (n = 1) demonstrated an open defect lacking tissue coverage, evidence of spinal cord injury, increased caspase-3, Iba1 and GFAP in spinal cord tissues, and hindbrain herniation and ventricular dilation. RTG treated fetuses (n = 3) demonstrated defect healing with well-organized dermal and epidermal layers throughout the entire healed tissue area overlaying the defect with minimal inflammation, reduced caspase-3, Iba1 and GFAP in spinal cord tissues, and no hindbrain herniation or ventricular dilation.

CONCLUSION

An RTG patch applied to MMC defects in fetal sheep promoted skin coverage over the defect, was associated with minimal inflammation of the spinal cord tissues and prevented brain abnormalities. The present findings provide exciting results for future comprehensive radiological, functional, and mechanistic evaluation of the RTG.

Modern fetal surgery-a historical review of the happenings that shaped modern fetal surgery and its practices

The history of fetal surgery is one of constant evolution. Over the last 50 years, fetal surgery has progressed from a mere idea to an internationally respected innovative field of surgery. This article aims to provide a historical review of how the enterprise of maternal-fetal surgery came to be its modern version. This review is less focused on the history of specific therapies for a relatively small number of conditions, and more on how the whole field of maternal-fetal surgery evolved. The various internal and external influences that steered the field's evolution are discussed in chronologic order. Since the start of modern fetal surgery in the 1980s, large paradigm shifts have characterized the growth of the field as a whole. Innovative interventions are now based on physiologic manipulation as opposed to simple anatomic repair, fetoscopy has become the more frequently preferred surgical approach, and rigorous scientific evaluation with randomized controlled trials is now the standard expected by the community. In a very similar fashion to when the field first began in the early 1980s, recently community's leaders have risen to protect the integrity of maternal-fetal surgery by publishing ethical guidelines for innovation and clinical practice. This incredible history of innovation, rigorous science and ethical contemplation is the foundation on which modern maternal-fetal surgery rests.

Advances and Trends in Pediatric Minimally Invasive Surgery

As many meta-analyses comparing pediatric minimally invasive to open surgery can be found in the literature, the aim of this review is to summarize the current state of minimally invasive pediatric surgery and specifically focus on the trends and developments which we expect in the upcoming years. Print and electronic databases were systematically searched for specific keywords, and cross-link searches with references found in the literature were added. Full-text articles were obtained, and eligibility criteria were applied independently. Pediatric minimally invasive surgery is a wide field, ranging from minimally invasive fetal surgery over microlaparoscopy in newborns to robotic surgery in adolescents. New techniques and devices, like natural orifice transluminal endoscopic surgery (NOTES), single-incision and endoscopic surgery, as well as the artificial uterus as a backup for surgery in preterm fetuses, all contribute to the development of less invasive procedures for children. In spite of all promising technical developments which will definitely change the way pediatric surgeons will perform minimally invasive procedures in the upcoming years, one must bear in mind that only hard data of prospective randomized controlled and double-blind trials can validate whether these techniques and devices really improve the surgical outcome of our patients.

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.

Spinal Cord Injury in Myelomeningocele: Prospects for Therapy

Myelomeningocele (MMC) is the most common congenital defect of the central nervous system and results in devastating and lifelong disability. In MMC, the initial failure of neural tube closure early in gestation is followed by a progressive prenatal injury to the exposed spinal cord, which contributes to the deterioration of neurological function in fetuses. Prenatal strategies to control the spinal cord injury offer an appealing therapeutic approach to improve neurological function, although the definitive pathophysiological mechanisms of injury remain to be fully elucidated. A better understanding of these mechanisms at the cellular and molecular level is of paramount importance for the development of targeted prenatal MMC therapies to minimize or eliminate the effects of the injury and improve neurological function. In this review article, we discuss the pathological development of MMC with a focus on in utero injury to the exposed spinal cord. We emphasize the need for a better understanding of the causative factors in MMC spinal cord injury, pathophysiological alterations associated with the injury, and cellular and molecular mechanisms by which these alterations are induced.

SARS-CoV2 (COVID-19) infection: is fetal surgery in times of national disasters reasonable?

Even though the global COVID‐19 pandemic may affect how medical care is delivered in general, most countries try to maintain steady access for women to routine pregnancy care, including fetal anomaly screening. This means that, also during this pandemic, fetal anomalies will be detected, and that discussions regarding invasive genetic testing and possibly fetal therapy will need to take place. For patients, concerns about Severe Acute Respiratory Syndrome‐Corona Virus 2 will add to the anxiety caused by the diagnosis of a serious fetal anomaly. Yet, also for fetal medicine teams the situation gets more complex as they must weigh up the risks and benefits to the fetus as well as the mother, while managing a changing evidence base and logistic challenges in their healthcare system.