Endoscopic in utero tracheal plugging in the fetal lamb to treat congenital diaphragmatic hernia

A case control surgical trial was performed in 13 time-dated pregnant ewes to evaluate the feasibility and pulmonary effects of intratracheal obstruction by an endoscopically positioned balloon. Fifteen fetuses were subjected to tracheoscopic balloon obstruction for progressively longer periods (range 2-18 days). In case of multiple pregnancies, 10 other fetuses were used as negative controls. A 1.2-mm miniscope with a double-lumen sheath and a detachable balloon were used. Feasibility of the technique was assessed in all animals based on operating time, intraoperative complications, and tracheal obstruction. Pulmonary effects were assessed by lung-to-body weight ratio (LBWR) and morphometric terminal brachial density (MTBD). In 14 animals the trachea was successfully obstructed until delivery. Tracheoscopic manipulation time ranged from 3 to 14 minutes. One intraoperative death occurred, but the contralateral control fetus also died during the procedure. When obstruction lasted for more than 7 days, the mean LBWR was 0.060 ± 0.01 (range 0.051-0.075) and in controls 0.031 ± 0.01 (range 0.017-0.039, p <0.0005). The MTBD was 0.65 ± 0.59, compared with 1.30 ± 0.80 for controls. Using a simple and fast technique of fetoscopic tracheoscopy, the trachea can be obstructed, leading to pulmonary hyperplasia, which is of potential value when treating congenital diaphragmatic hernia.