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.

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.

INTRODUCTION: This is the cumulative technical report on the operative procedures and limitations of fetoscopic bag insertion, intestinal bag placement, and bag fixation to the fetus in a series of pilot studies in an ovine model for prenatal treatment of gastroschisis. MATERIAL AND METHODS: In 24 German blackhead sheep, a surgically created gastroschisis was managed by fetoscopic placement of the extruded intestines into a bag. The bag was then fastened onto the fetal abdominal wall. Different materials (sterile gloves, latex condoms, laparosopic retrieval bags) and different fixation techniques (laparoscopic staplers, interrupted and continuous sutures) have been examined. The fetuses were retrieved and evaluated at the end of gestation. RESULTS: Uterine bag insertion was successful in 15 of 24 (62.5%) and intestinal bag placement in 10 of 15 available fetuses (66.6%). The main factor limiting fetoscopic procedures was chorioamniotic separation (CAS). Sterilized condoms provided the most appropriate type of bags and the V-Loc™ running suture, the most expedient type of fixation, which was achieved in 9 of the 10 fetuses (complete = 2, partially = 7) by using a three port access (5 mm and 2 × 3 mm). All bags were encountered completely or partially dislocated from the fetus at the end of gestation. CONCLUSIONS: Fetoscopic intestinal bag placement and fixation in gastroschisis technically demanding. None of the evaluated techniques led to permanent anchorage of the bag to the fetus. The development of specially designed instruments, bags and fixation methods is required to optimize this approach.