Intrauterine endoscopic creation of urinary tract obstruction in the fetal lamb: A model for fetal surgery

OBJECTIVE: Our purpose was to evaluate the feasibility of intrauterine endoscopic fetal surgery in a fetal lamb model by creating a urinary tract obstruction. STUDY DESIGN: Lower urinary tract obstruction was created by ligation of the urethra and urachus in 21 fetal lambs, eight at 95 to 105 daysʹ gestation (term 145 days) and 13 at 70 to 75 days. The endoscopic approach consisted of a 0-degree 5 mm telescope, three 5 mm cannulas, uterine distention by amnioinfusion, and adapted instrumentation. Intrauterine fetal monitoring included temperature and pulse oximetry registration. RESULTS: In 20 cases the urachus could be identified and ligated inside the umbilical cord. The urethra was ligated in the anterior abdominal wall (n = 7) obstructed at the level of the penis (n = 13). Mean fetal heart rate was 147 ± 35 beats/min, and fetal temperature at the end of intervention was 38.14° ± 2.1° C. The overall postoperative survival rate was 76%. CONCLUSION: Urinary tract obstruction can be created endoscopically in the fetal lamb. This operation can serve as a model for endoscopic fetal surgery.