Minimally Traumatic Techniques for In Utero Access and Fetal Surgery

BACKGROUND AND OBJECTIVES: Prenatal interventions may prevent some sequelae of congenital anomalies, yet open fetal surgery is limited by preterm labor. We are developing amnioscopic strategies to reduce risks for in utero surgery. METHODS: Seven fetal sheep were accessed percutaneously under ultrasound guidance, via maternal laparoscopy/transuterine trocars, or via laparoscopically assisted partial uterine exteriorization (mini-hysterotomy). Three fetal immobilization methods were investigated: 2 mm grasping forceps, 2-0 absorbable Roeder loop lasso, and detachable metal T-fasteners. RESULTS: Percutaneous access with 2 mm trocars required accessible amniotic fluid pockets. The laparoscopically assisted method enabled 5 mm trocar placement under direct fetal visualization. Mini-hysterotomy avoided trocars and was leak-proof. 2 mm graspers enabled fetal manipulation with repeatable applications. Roeder loop sutures were not readily repositioned, and required two 3 mm or larger trocars. T-fasteners were easily deployed into fetal skin via the self-contained needle applicator with minimal hemorrhage. Cutaneous marks were present immediately from the grasper and T-fastener, but not at postoperative day 10. The Roeder loop produced no observable effects. All devices demonstrated adequate intrauterine performance. CONCLUSIONS: Minimally invasive fetal surgery promises to lower maternal-fetal risks. All strategies permitted prolonged amnioscopy and fetal manipulation. The 2 mm grasper was easiest to use, producing no observable lasting trauma.