Fetoscopic techniques for prenatal covering of gastroschisis in an ovine model are technically demanding and do not lead to permanent anchoring on the fetus until the end of gestation

Development and Validation of a Minimally Invasive Transuterine Experimental Model of Gastroschisis

INTRODUCTION

Perinatal management of gastroschisis remains a subject of substantial research. Current models, including teratogenic, genetic, and surgical approaches, often fail to accurately replicate gastroschisis, exhibiting limitations such as inaccurate phenotyping, low success rates, high mortality, lack of scientific validation, and significant technical challenges. Refined disease models are essential for improving the understanding of GS. This study seeks to develop and validate a minimally invasive transuterine experimental model of GS that overcomes these existing constraints to advance gastroschisis research.

METHODS

A gastroschisis model was surgically created in rat fetuses at E17 (n = 51 fetuses from n = 13 dams). Intestines were harvested at term and divided into herniated gastroschisis (GS-H), intra-abdominal gastroschisis (GS-I), and control (Co) groups. Morphometric analysis, histopathological examination, immunohistochemistry for interstitial cells of Cajal (ICC), double immunofluorescence for ICC and mast cells, TUNEL assay for apoptotic cells, and multiplex cytokine assay were performed to assess intestinal architecture, inflammation, ICC network, apoptosis, and cytokine levels across studied groups.

RESULTS

Histology from GS intestines revealed subchronic inflammation, peel formation, and architectural disruption. Herniated intestines exhibited a significantly increased weight/length ratio and thicker outer layers (p < 0.001) compared with control intestines. Herniated intestines had elevated inflammatory cytokine levels (GS-H vs GS-I and Co, p < 0.05 for G-CSF, GM-CSF, IL-12p70, IL-1beta) and increased apoptotic activity.

CONCLUSIONS

We developed and validated a new surgical model of GS that offers improved survival and feasibility. The key morphological changes and molecular markers observed in this experimental model resemble human gastroschisis.

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.

Minimally Invasive Bimanual Fetal Surgery—A Review

Background: The aim of this review is to discuss experimental and clinical techniques and interventions of fetal surgery which have been performed minimally invasively by the means of a three-port approach for the fetoscope and instruments for the left and right hand of the surgeon (bimanual minimally invasive fetal surgery). Methods: a print and electronic literature search was performed; the titles and abstracts were screened and included reports were reviewed in a two-step approach. First, reports other than minimally invasive fetal surgery were excluded, then a full text review and analysis of the reported data was performed. Results: 17 reports were included. The heterogeneity of the included reports was high. Although reports on human fetoscopic surgical procedures can be found, most of them do not pick out bimanual fetal surgery as a central theme but rather address interventions applying a fetoscope with a working channel for a laser fiber, needle or flexible instrument. Most reports were on experimentation in animal models, the human application of minimally invasive fetoscopic bimanual surgery is rare and has at best been explored for the prenatal treatment of spina bifida. Some reported bimanual fetoscopic procedures were performed on the exteriorized uterus via a maternal laparotomy and can therefore not be classified as being truly minimally invasive. Discussion: our results demonstrate that minimally invasive fetoscopic bimanual surgery is rare, even in animal models, excluding many other techniques and procedures that are loosely termed ‘minimally invasive fetal surgery’ which we suggest to better label as ‘interventions’. Thus, more research on percutaneous minimally invasive bimanual fetoscopic surgery is warranted, with the aim to reduce the maternal, uterine and fetal trauma for correction of congenital malformations.

Predicting Factors of Protracted Intestinal Failure in Children with Gastroschisis

OBJECTIVE

To identify prenatal and neonatal predictors of short bowel syndrome-related intestinal failure (SBS-IF) in gastroschisis.

STUDY DESIGN

This retrospective study included all patients with gastroschisis born between 2000 and 2017 who were enrolled in our home parenteral nutrition program, and all patients with gastroschisis born in our institution who survived 2 weeks, during the same time period. Prenatal ultrasound features, neonatal status, anatomic features, oral feeding, and parenteral nutrition dependency were analyzed.

RESULTS

Among 180 patients, 35 required long-term parenteral nutrition (SBS-IF group) and 145 acquired full oral feeding within 6 months (oral feeding group). The mean follow-up was 7.9 years (IQR, 1.6-17.5 years) and 5.0 years (IQR, 0.1-18.2 years), respectively. Both bowel matting (OR, 14.23; 1.07-16.7; P = .039) and secondarily diagnosed atresia or stenosis (OR, 17.78; 3.13-100.98; P = .001) were independent postnatal predictors of SBS-IF. Eighteen children (51% of the SBS-IF group) were still dependent on artificial nutrition at the last follow-up. patients with SBS-IF who achieved full oral feeding had a median residual small-bowel length of 74 cm (IQR, 51-160 cm) vs 44 cm (IQR, 10-105 cm) for those still dependent on artificial nutrition (P = .02). An initial residual small bowel length of more than 50 cm was the best predictive cut-off for nutritional autonomy, with a sensitivity of 67% and a specificity of 100%.

CONCLUSIONS

Bowel matting, complex gastroschisis, and secondary intestinal obstruction were associated with SBS-IF in gastroschisis. For patients with SBS-IF, a small bowel length of more than 50 cm was predictive of secondary nutritional autonomy.

Fetal Surgery for Gastroschisis—A Review with Emphasis on Minimally Invasive Procedures

(1) Background: The morbidity of gastroschisis is defined by exposure of unprotected intestines to the amniotic fluid leading to inflammatory damage and consecutive intestinal dysmotility, the viscero-abdominal disproportion which results in an abdomen too small to incorporate the herniated and often swollen intestine, and by associated pathologies, such as in complex gastroschisis. To prevent intestinal damage and to provide for growth of the abdominal cavity, fetal interventions such as amnio exchange, gastroschisis repair or covering have been evaluated in several animal models and human trials. This review aims to evaluate the reported techniques for the fetal treatment of gastroschisis by focusing on minimally invasive procedures. (2) Methods: We conducted a systematic database search, quality assessment and analyzed relevant articles which evaluate or describe surgical techniques for the prenatal surgical management of gastroschisis in animal models or human application. (3) Results: Of 96 identified reports, 42 eligible studies were included. Fetal interventions for gastroschisis in humans are only reported for EXIT procedures and amnio exchange. In animal models, particularly in the fetal sheep model, several techniques of open or minimally invasive repair of gastroschisis or covering the intestine have been described, with fetoscopic covering being the most encouraging. (4) Discussion: Although some promising minimally invasive techniques have been demonstrated in human application and animal models, most of them are still associated with relevant fetal morbidity and mortality and barely appear to be currently applicable in humans. Further research on specific procedures, instruments and materials is needed before any human application.

Abdominal wall defects

Abdominal wall defects are common congenital anomalies with the most frequent being gastroschisis and omphalocele. Though both are the result of errors during embryologic development of the fetal abdominal wall, gastroschisis and omphalocele represent unique disorders that have different clinical sequelae. Gastroschisis is generally a solitary anomaly with postnatal outcomes related to the underlying integrity of the prolapsed bowel. In contrast, omphalocele is frequently associated with other structural anomalies or genetic syndromes that contribute more to postnatal outcomes than the omphalocele defect itself. Despite their embryological differences, both gastroschisis and omphalocele represent anomalies of fetal development that benefit from multidisciplinary and translational approaches to care, both pre- and postnatally. While definitive management of abdominal wall defects currently remains in the postnatal realm, advancements in prenatal diagnostics and therapies may one day change that. This review focuses on recent advancements, novel techniques, and current controversies related to the prenatal diagnosis and management of gastroschisis and omphalocele.

Stereological Lung Parameters After Fetoscopic Abdominal Decompression of Congenital Diaphragmatic Hernia in an Ovine Model: A Pilot Study

Background: Fetoscopic endoluminal tracheal occlusion (FETO) improves lung maturation in severe cases of congenital diaphragmatic hernia (CDH) but it does not ameliorate lung compression by herniated abdominal organs. Surgically opening the fetal abdomen (abdominal decompression [AD]) reduces the intrathoracic pressure by diverting the abdominal organs into the amniotic cavity-a probable causal therapy for lung hypoplasia and pulmonary hypertension in CDH. Open surgical abdominal decompression has been reported: we describe a minimally invasive approach in an ovine model of CDH as a probable fetoscopic intervention. Materials and Methods: Eight fetuses were included, 2 were kept as HEALTHY controls. A CDH (left side, liver down) was created by open fetal surgery at midgestation in 6 fetuses, 2 were taken as CDH controls. Fetoscopic abdominal decompression (fAD) was performed 21 days later in 4 animals. The fetuses were retrieved at the end of gestation and evaluated by lung stereology. Results: fAD led to a near total evacuation of the thoracic cavity in 2 of the 4 animals. Fetuses with CDH had a lower total volume and fraction of alveolar air space, a lower volume fraction of the parenchyma, and an increase of the volume fraction of the alveolar septa and atelectasis, as well as an increased mean thickness of alveolar septa compared with HEALTHY fetuses. Fetuses treated with abdominal decompression showed an improvement of stereological parameters. Conclusions: In spite of relevant limitations (pilot study, small groups, spontaneous closure of the abdominal incision) we were able to demonstrate that abdominal decompression for CDH can be performed by fetoscopy. Our results support the hypothesis of causally improving lung development by abdominal decompression, thus implying increased survival in extreme cases of CDH. A refinement of the fetoscopic techniques and direct comparison to FETO appears warranted.

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.