Two-port, exteriorized uterus, fetoscopic meningomyelocele closure has fewer adverse neonatal outcomes than open hysterotomy closure

Proof of concept testing of a vascular closure device for use in fetal surgery

OBJECTIVE

Prior clinical findings have demonstrated that maternal laparotomy with trans-amniotic trans-uterine suturing of the fetoscopic port site during in utero myelomeningocele repair reduces the risk of membrane rupture. However, due to laparotomy-associated morbidity, we aimed to explore the feasibility of using a vascular closure device for percutaneous trans-amniotic trans-uterine suturing.

METHODS

This IRB and IACUC-exempt study utilized 2 strategies for proof-of-concept testing of using the Abbott Perclose™ ProStyle™ Device for suture placement; 1. Ultrasound guided application on a high fidelity maternal abdominal uterus model used for fetal procedures and 2. Placement under direct visualization with sheep undergoing cesarean delivery for other research purposes. In the high-fidelity uterus model, the Abbott Perclose™ ProStyle™ device was used to place a transuterine/transamniotic stitch with accompanying video recording of the approach (https://go.screenpal.com/watch/cZfhoDVsYvW password: perclose). Regarding the second approach, at the time of a cesarean section, 12 French Checkflo® cannulas were inserted into the sheep amniotic space via different approaches: (1) Seldinger technique, (2) Seldinger technique insertion of Checkflo® cannula and subsequent use of the Abbott Perclose™ ProStyle™ device to suture the port site after check flow removal, (3) Abbott Perclose™ ProStyle™ device utilized in what is described as a "pre-close" technique, where prior to cannula placement, trans-uterine trans-amniotic stitches are placed followed by the insertion of a 12 French Checkflo® cannula over the same guidewire. Samples of the sutured uterine wall were sent to pathology and H&E staining was performed to assess uterine hole closure and amnion-to-uterus fixation.

RESULTS

The high-fidelity model confirmed that the Perclose™ ProStyle™ Device was easily visualized by ultrasound and suture deployment was without complication. In the animal model, the Perclose™ ProStyle™ device effectively sutured the amnion to the uterus in both the pre- and post-close approach. The pre-close technique achieved better amnion-to-uterus approximation and more appropriate uterine hole closure. H&E staining revealed that without suturing, amnion separation from the chorion layer occurred, and the uterine hole persisted. The post-close technique showed partial connection between the amnion and chorion, but inadequate uterine hole closure with amnion shift into the defect. Optimal closure, with secure amnion-to-chorion fixation and uterine closure, was achieved through the pre-close technique.

CONCLUSION

The Abbott Perclose™ ProStyle™ Device seems to be a feasible device for use of uterine port closure in maternal-fetal surgery, larger animal studies with mid-pregnancy application are needed to further validate or refute these findings.

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.

Initial experience with the anaesthetic management of fetoscopic spina bifida repair at a German University Hospital: A case series of 15 patients

Spina bifida aperta (SBA) is a serious neural tube defect that can lead to a range of disabilities and health complications in affected individuals. In recent years, fetoscopic surgical repair has emerged as a promising new approach to treat spina bifida prenatally, offering the potential for improved outcomes compared with traditional open surgery. As one of the few centres in Europe to offer this innovative technique, the Departments of Obstetrics and Gynaecology, Neurosurgery, and Anaesthesiology and Intensive Care Medicine at the University Medical Centre of Marburg (UKGM Marburg) have faced unique challenges in developing and establishing standards of care for the pregnant patients undergoing this complex procedure. In this publication, we aim to present details of our initial experience with the first 15 patients and propose a clinical concept for the rather complex perioperative management of these patients.

Exteriorization of the uterus reduces fetoscopic cannula-induced stress and strain: A finite element model analysis

OBJECTIVE

To estimate stresses and strains in the uterine wall and fetal membranes with single/multi-port fetoscopy, simulating either a percutaneous access or via exteriorized uterus.

STUDY DESIGN

Finite element models based on anatomical dimensions, material properties and boundary conditions were created to simulate stresses, strains and displacements on the uterine wall and fetal membranes during simulated fetal surgery either via exteriorized uterus or percutaneous approach, and with one or three cannulas. Clinically, we measured the anatomical layer thickness and cannula entry point displacement in patients undergoing single port percutaneous fetoscopy.

RESULTS

Simulations demonstrate that single port percutaneous fetoscopy increases stress on the fetal membranes (+105%, 128 to 262 kPa) and uterine wall (+115%, 0.89 to 1.9 kPa) compared to exteriorized uterine access. Using three ports increases stress by 110% (148 to 312 kPa) on membranes and 113% (1.08 to 2.3 kPa) on uterine wall. Finite Element Method showed 0.75 cm uterine entry point displacement from the cutaneous entry, while clinical measurements demonstrated displacement of more than double (1.69 ± 0.58 cm), suggesting modeled measurements may be underestimations.

CONCLUSION

The stresses and strains on the fetal membranes and uterus are double as high when entering percutaneously than via an exteriorized uterus. Based on what can be clinically measured, this may be an underestimation.

Implementation and Assessment of a Laparotomy-Assisted Three-Port Fetoscopic Spina Bifida Repair Program

Open spina bifida (OSB) is a congenital, non-lethal malformation with multifactorial etiology. Fetal therapy can be offered under certain conditions to parents after accurate prenatal diagnostic and interdisciplinary counseling. Since the advent of prenatal OSB surgery, various modifications of the original surgical techniques have evolved, including laparotomy-assisted fetoscopic repair. After a two-year preparation time, the team at the University of Giessen and Marburg (UKGM) became the first center to provide a three-port, three-layer fetoscopic repair of OSB via a laparotomy-assisted approach in the German-speaking area. We point out that under the guidance of experienced centers and by intensive multidisciplinary preparation and training, a previously described and applied technique could be transferred to a different setting.

Minimally Invasive Fetal Surgery and the Next Frontier

Most patients with congenital anomalies do not require prenatal intervention. Furthermore, many congenital anomalies requiring surgical intervention are treated adequately after birth. However, there is a subset of patients with congenital anomalies who will die before birth, shortly after birth, or experience severe postnatal complications without fetal surgery. Fetal surgery is unique in that an operation is performed on the fetus as well as the pregnant woman who does not receive any direct benefit from the surgery but rather lends herself to risks, such as hemorrhage, abruption, and preterm labor. The maternal risks involved with fetal surgery have limited the extent to which fetal interventions may be performed but have, in turn, led to technical innovations that have significantly advanced the field. This review will examine congenital abnormalities that can be treated with minimally invasive fetal surgery and introduce the next frontier of prenatal management of fetal surgical pathology.

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.