Background: In order to minimize maternal trauma from current techniques for temporary fetoscopic tracheal occlusion, we tried to develop a percutaneous fetoscopic technique in sheep.
Methods: In nine ewes between 77 and 128 days of gestation, the amniotic cavity was entered percutaneously. Each fetus was positioned and the feasibility of fetal laryngoscopy and percutaneous fetoscopic tracheal balloon occlusion was assessed.
Results: Percutaneous intraamniotic access, fetal positioning, oropharyngeal sheath insertion, and fetoscopic laryngoscopy were achieved in all nine fetal sheep. Following some technical modifications to the working channel of the fetoscope, percutaneous fetoscopic tracheal balloon occlusion was successfully achieved in the last seven sheep.
Conclusion: Percutaneous fetoscopic balloon occlusion of the fetal trachea can effectively and safely be achieved in sheep. Because intraamniotic spatial relationships, fetal position, and umbilical cord length are technically less favorable in sheep, our operative techniques might be feasible in humans even if difficult intraamniotic conditions are encountered.