Fetoscopic Tracheal Occlusion (FETO) for Severe Congenital Diaphragmatic Hernia: Evolution of a Technique and Preliminary Results

Abstract

Approximately half of fetuses having isolated congenital diaphragmatic hernia (CDH) survive after postnatal surgery. The other half die of pulmonary hypoplasia and pulmonary hypertension. Animal studies have shown that pulmonary hypoplasia and hypertension can be reversed by intrauterine repair that restores herniated viscera to the abdomen. The authors describe a minimally invasive and reversible technique of fetoscopic tracheal balloon occlusion (FETO) designed for use in fetuses with severe CDH (Fig. 1). A prospective study enrolled 21 consecutive severely affected fetuses who were otherwise normal anatomically and chromosomally. Intrathoracic herniation of the liver was present in all cases. Under general or combined spinal-epidural anesthesia, the fetal position is altered if necessary to maximize access to the trachea. A flexible Teflon cannula containing a pyramidal trocar is placed in the amniotic cavity through the abdominal wall and uterine wall and directed toward the fetal mouth. The trocar is withdrawn and special fetoscopic instruments are inserted: a sheath loaded with a fiber endoscope and a catheter loaded with a detachable gold valve balloon. There also is a side connector permitting amnioinfusion with Hartmann solution. After passing the endoscope through the vocal cords to the trachea, the catheter is positioned to deliver the balloon just above it. The balloon is inflated with isotonic Omniscan, a magnetic resonance imaging contrast agent. The balloon is removed at approximately 34 weeks gestation, either by fetal tracheoscopy or by puncturing the balloon with an ultrasound-guided needle. The balloon was correctly placed in all 21 cases, on the first try in 16 of them. There were no serious maternal complications. The lungs were more echogenic within 48 hours, and the lung area-to-head circumference ratio improved from a median of 0.7 to 1.8 within 2 weeks. The median gestational age at delivery was 34 weeks, and in approximately three fourths of cases, it was more than 32 weeks. Nine newborn infants died from complications of pulmonary hypoplasia. Ten of 12 infants having surgical repair of CDH were doing well after a median of 18 months. Survival improved from 30% in the first 10 cases to 64% in the next 11, corresponding to a shift in the timing of FETO from the third to the second trimester, and also the use of epidural rather than general anesthesia. Only 1 of 12 control infants not given prenatal therapy lived to be discharged. This experience means that fetal surgery is feasible in cases of severe CDH when using a minimally invasive technique. Postnatal survival may improve as a result.