Fetoscopic Surgery for in-Utero Management of Congenital Diaphragmatic Hernia

Abstract

INTRODUCTIONUntil recently two possibilities were available to the expectant parents of a fetus diagnosed with a congenital diaphragmatic hernia: termination of pregnancy or continuation of the pregnancy until term with a potential change in the place of delivery. Open fetal surgery has been used to treat a growing number of congenital malformations with life-threatening or highly morbid consequences including congenital diaphragmatic hernia. 1 However, its effectiveness is limited by the occurrence of preterm labour, chorioamniotic membrane separation, preterm prelabour rupture of the membranes and altered fetal homeostasis. 2 These problems were the impetus for the development of minimal access fetal surgery. Developments in endoscopic surgical technology over the past three decades have provided the opportunity to develop techniques adapted for prenatal fetal intervention. 3 RATIONALE FOR FETOSCOPIC SURGERYExperimental studies on the effect of minimal access fetal surgery suggest that it reduces preterm labour and achieves better maintenance of fetal and maternal homeostasis. 4 With respect to preterm labour fetoscopic access in mid-trimester Rhesus monkeys did not result in any significant uterine contractions by 24 hours post-operatively. 5 Subsequent recordings of myometrial activity were repeated during the third trimester, and no premature contractions were noted. In contrast, Luks and colleagues studying third trimester sheep found that uterine contractions were present 52% of the time after maternal laparotomy irrespective of whether a hysterotomy or fetoscopic access using three ports was performed. 6 These myometrial contractions were noted in response to access only, as no fetal manipulation was undertaken. The primate uterus resembles the human uterus much more closely than the ovine and is generally accepted as a good model for studies into human parturition, questioning the application of ovine myometrial activity studies to the human situation.With respect to maternal-fetal homeostasis, Luks demonstrated in the same study a significant 27% reduction in uterine blood flow and utero-placental oxygen delivery with hysterotomy creation, whereas endoscopic access had no effect. 6 When uterine artery flow and thus oxygen delivery is reduced to 70% of control, there is a shift in fetal blood flow distribution, a decrease in fetal pH and an increase in serum lactate. 7 It is likely that oxygen delivery would be further impaired during open fetal surgery, by manipulation of the uterus, active pressure on uterine vessels and traction or compression of the umbilical cord. Therefore the endoscopic approach, which does not alter uteroplacental oxygen delivery, would be preferable. Clinical experience with human fetoscopic surgery reflects this experimental work. Fetoscopic intervention produces less preterm labour with less use of tocolytics, decreased maternal hospital stay and decreased maternal complications related to tocolysis. 8

Cross-sectional Study of Tracheomegaly in Children after Fetal Tracheal Occlusion for Severe Congenital Diaphragmatic Hernia

“…Antenatal intervention is performed to trigger lung growth rather than to correct the diaphragmatic defect, which can be easily repaired after birth. Tracheal occlusion prevents egress of lung liquid produced by the airway epithelium and induces tissue stretch, which acts as a signal for lung growth ( 4,5 ). Prenatal release of the occlusion stimulates lung maturation ( 6 ).…”

Fetal Surgery for Congenital Diaphragmatic Hernia Is Back from Never Gone

“…The eventual effect of TO is dependent on timing, duration and reversal of the occlusion. The literature on this topic has been summarized elsewhere by Khan et al [51] and Nelson et al [52] . Briefly, TO increases DNA synthesis, which peaks after 2 days and is largely complete by 4 days [53] .…”

The making of fetal surgery

“…Nearly normal lung growth and maturation was achieved in sheep by a cyclical occlusion protocol, that is, a 47 h occlusion period altered by 1 h release, and this between 110 and 138 days (Nelson et al, 2005). For further details on these and other studies related to experimental tracheal occlusion, we refer to some comprehensive reviews (Nelson et al, 2006;Khan et al, 2007).…”