In utero Hepatitis B Immunization during Fetal Surgery for Spina Bifida

Prenatal Spina Bifida Repair: Defendable Trespassing of MOMS Criteria Results in Commendable Personalized Medicine

INTRODUCTION

We hypothesize that after publication of the quintessence of the MOMS trial, eligibility criteria for prenatal spina bifida (SB) repair may be modified if a tenable argumentation underlies this decision.

METHODS

Our first 154 fetal surgery patients were analyzed with particular focus on how many, which, and why the original eligibility criteria, set forth by the MOMS Trial Protocol, were disobeyed, and what the eventually detectable, negative and positive impacts of these deviations on outcomes were.

RESULTS

A total of 152 patients (2 missing consent) were included (100%). In 69 patients (45.4%), a total of 89 eligibility criteria were disobeyed. In 54 (35.6%) cases, the following maternal criteria were concerned: gestational age at operation of >25+6 weeks in 17 (11.2%), uterine pathologies in 13 (8.6%) women, preoperative BMI ≥35 kg/m2 in 12 (7.9%), previous hysterotomy in 7 (4.6%), previous prematurity in 3 (2%), HIV/hepatitis B in 2 (1.3%), psychosocial issues in 2 (1.3%), and placenta praevia in 1 (0.7%). In 32 (21.1%) cases, fetal criteria were disobeyed 34 times: Fetal anomaly unrelated to SB in 19 (12.5%), no/minimal evidence of hindbrain herniation in 13 (8.6%), and severe kyphosis in 2 (1.3%). We could not identify cases where non-observation of criteria led to clear-cut maternal and/or fetal disadvantages.

CONCLUSION

This study shows that MOMS trial eligibility criteria for prenatal SB repair should be modified or even abandoned with adequate medical and ethical argumentation, and with written parental informed consent after non-directive, full disclosure counseling. This clear-cut change of paradigm is a necessity as it leads toward personalized medicine, allowing more fetuses to benefit from fetal surgery than would have benefitted with the former, published, MOMS criteria in place.

M-Sign in Middle Cerebral Artery Doppler Waveforms: A Sign of Fetal Vasoconstriction Before and After Open Fetal Spina Bifida Repair

BACKGROUND

Increased pulse wave reflection in the fetal arterial system, illustrated by a second systolic peak (M-sign) in middle cerebral artery (MCA) Doppler waveforms, allows interpretation of fetal systemic vasoconstriction. Little is known about fetal vascular regulation during fetal spina bifida (fSB) repair. Therefore, the aim of this study was to analyze MCA-Doppler waveform changes before, during, and after fSB repair.

PATIENTS AND METHODS

31 pregnant women who underwent fSB repair were included. Fetal MCA-Doppler waveforms were prospectively analyzed before, during and after fSB repair, and categorized as follows: normal systolic downslope, systolic shoulder, second systolic peak (M-sign), and concave systolic downslope. These MCA waveforms were related to maternal and fetal characteristics, to anesthetic medication, and to umbilical artery (UA) waveforms.

RESULTS

Before fSB repair, all fetuses repeatedly presented M-signs. After initiation of desflurane for general anesthesia, systolic shoulder and the M-sign vanished in 24/31 (78%) fetuses and 19/31 (61%) showed transient UA ARED flow. A significant association between these two Doppler findings was found (p=0.007). After fSB repair, signs of increased pulse wave reflection reappeared but resolved over time (23 days ± 20, SD) in all fetuses.

CONCLUSION

Both fSB and intrauterine repair influence fetal vascular regulation. This phenomenon can be illustrated by MCA-Doppler waveforms. While anesthetic agents transiently eliminated M-signs and often provoked a UA ARED flow, fSB repair finally led to normalization of MCA-Doppler waveforms indicating return to normal fetal vascular regulation.

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.

Systematic classification of maternal and fetal intervention-related complications following open fetal myelomeningocele repair - results from a large prospective cohort

OBJECTIVE

To systematically categorise all maternal and fetal intervention-related complications after open fetal myelomeningocele (fMMC) repair of the first 124 cases operated at the Zurich Centre for Fetal Diagnosis and Therapy.

DESIGN

A prospective cohort study.

SETTING

Single centre.

POPULATION

Mothers and fetuses after fMMC repair.

METHODS

Between 2010 and 2019, we collected and entered all maternal complications following fMMC repair into the Clavien-Dindo classification. For fetal complications, a classification system based on the Medical Dictionary for Regulatory Activities terminology of Adverse Events was used including the preterm definitions of the World Health Organization.

MAIN OUTCOME MEASURES

Systematic classification of maternal and fetal complications following fMMC repair.

RESULTS

Gestational ages at surgery and birth were 25.0 ± 0.8 and 35.4 ± 2.0 weeks, respectively. In 17% of all cases, no maternal complications occurred. Maternal intervention-related complications were observed as follows: 69% grade 1, 36% grade 2, 25% grade 3, 6% grade 4 and 0% grade 5. In 34%, no fetal complications were noted; however, 43% of the fetuses developed a grade 1, 14% a grade 2, 8% a grade 3, 2% a grade 4 and 2% a grade 5 complication.

CONCLUSION

This study raises awareness of complications following open fMMC repair; 6% of mothers and 2% of fetuses experienced a severe complication (grade 4) and perinatal death rate of 2% was observed (grade 5). These data are useful for prenatal counselling, they help to improve the system of fetal surgical care, and they allow benchmarking with other centres as well as comparison with fetoscopic approaches.

TWEETABLE ABSTRACT

Systematic classification of all maternal and fetal intervention-related complications following open fMMC repair.

Bio-engineering of fetal cartilage for in utero spina bifida repair

PURPOSE

During in utero surgical spina bifida repair, a multi-layer closure is used to cover the defect. These soft tissues, however, might be not sufficient to protect the spinal cord during the future life. Our goal is to develop a more rigid protective tissue construct consisting of bioengineered cartilage and skin.

METHODS

Ovine fetal chondrocytes were tested for their in vitro chondrogenic potential in three-dimensional cultures. Scaffolds based on natural biopolymers (collagen I, fibrin glue) were loaded with varying amounts of fetal chondrocytes and assessed for their ability to support cartilage formation in vitro. The bioengineered constructs were analyzed using cartilage-specific histology stainings and compared to native fetal cartilage.

RESULTS

Fetal chondrocytes actively produced cartilage extracellular matrix in three-dimensional cultures, even at high passages. Among all bioengineered scaffolds, only the collagen I-based hydrogels loaded with high densities of fetal chondrocytes showed cartilage-like structure in vitro but also extensive shrinking.

CONCLUSION

Fetal chondrocytes represent a good cell source for cartilage bioengineering. Collagen I scaffolds support cartilage formation in vitro, but the construct shrinking constitutes a major limitation. Future steps include the identification of suitable bioprintable materials which maintain their shape and size, as well as the analysis of the interphase between bioengineered cartilage and skin.