This procedure allows the fetus to remain perfused by the placenta after being partially delivered, so that lifesaving treatment can be performed before completing the delivery. The technique was irst developed to obtain an airway with fetal tumors involving the oropharynx and neck (Catalano, 1992; Kelly, 1990; Langer, 1992). An ex-utero intrapartum treatment (EXIT) procedure is performed by a multidisciplinary team, which may include an obstetrician, maternal-fetal medicine specialist, pediatric surgeon(s), pediatric otolaryngologist, pediatric cardiologist, anesthesiologists for the mother and fetus, and neonatologists, as well as specially trained nursing personnel. Components of the procedure are shown in Table 16-5.
Selected indications are listed in Table 16-2. EXIT is the preferred procedure for intrapartum management oflarge venolymphatic malformations of the neck such as the one shown in Figure 16-9. At the Children's Hospital of Philadelphia, criteria for EXIT with a cervical venolymphatic malformation include compression, deviation, or obstruction of the airway by the mass, and also involvement of the floor of the mouth (Laje, 2015). In a review of 112 pregnancies with fetal cervical venolymphatic malformations, only about 10 percent met these criteria. Other indications for EXIT include severe micrognathia and congenital high airway obstruction sequence (CHAOS), which are discussed in Chapter 10 (Figs. 10-20 and 10-26, p. 197). Criteria for an EXIT procedure for micrognathia include a fetal jaw measurement below the 5th percentile along with indirect evidence of obstruction, such as hydramnios, an absent stomach bubble, or glossoptosis (Morris, 2009b). Case selection for EIT procedures is generally based on fetal 1R imaging findings (Chap. 10, p. 219).
FIGURE 16-9 Ex-utero intrapartum treatment (EXID procedure for a venolymphatic malformation. A. Upon delivery of the head, placental circulation was maintained and an airway was established over the course of 20 minutes by a team of pediatric subspecialists that included a surgeon, anesthesiologist, and otolaryngologist. B. Following a controlled intubation, the fetus was ready for delivery and transfer to the neonatal intensive care unit team. (Used with permission from Drs. Stacey Thomas and Patricia Santiago-Munoz.)
In some cases, an EIT procedure has been used as a bridge to other procedures. For example, resection of large thoracic masses may be accomplished by fetal thoracotomy performed with intact placental circulation. In a series of 16 fetuses with CCM volume ratiosi> 1.6 or hydrops, all of whom had mediastinal compression, Cass and colleagues (2013) reported that nine infants undergoing EIT-to-resection survived. In contrast, there were no survivors with urgent postnatal surgery alone. Similarly, Moldenhauer (2013) reported that 20 of 22 newborns treated with EXIT -to-resection for lung masses survived. he EIT procedure has also been used as a bridge to extracorporeal membrane oxygenation-EIT-to-ECMO-in pregnancies with severe congenital diaphragmatic hernia. However, it has not been found to clearly confer survival benefit in such cases (Morris, 2009a; Shieh, 2017; Stofan, 2012).