Fetoscopic abdominal decompression of congenital diaphragmatic hernia – preliminary results of a fetal sheep model

Background Severe congenital diaphragmatic hernia (CDH) is prenatally managed by fetoscopic tracheal occlusion (FETO) to improve lung growth and maturation. As FETO is not able to reduce the pressure onto the developing lungs originating from the intestine growing into the thoracic cavity, fetal abdominal decompression may alleviate this pressure effect by directing the growing intestine into the amniotic cavity away from the lungs. Therefore, aim of this study was to establish an animal model for fetoscopic abdominal decompression in fetal sheep with CDH. Methods CDH was created surgically on day 75 of 145 day gestation in eight fetuses. 2-3 weeks later, an opening was created in the fetal abdomen by fetoscopic surgery. The fetuses were retrieved by cesarean section at the end of pregnancy and evaluated. Results Five fetuses with CDH were treated with fetoscopic abdominal decompression. Three fetuses with CDH were taken as controls. One fetus was lost after creation of the CDH and two other after creation of the abdominal defect. Preliminary sterological results showed that the septal thickness of the experimental group was smaller than in the CDH group. Conclusion This study demonstrates the general feasibility of fetoscopic abdominal decompression for diaphragmatic hernia in our new animal model. Although not statistically significant, the lungs of treated fetuses were larger and heavier than those of untreated controls. Our findings support the hypothesis of palliative fetal surgery for severe CDH compared to tracheal occlusion. More controlled animal trials are needed.