Minimally traumatic techniques for in utero access and fetal surgery

Prenatal interventions may prevent some sequelae of congenital anomalies, yet open fetal surgery is limited by pre-term labor. We are developing amnioscopic strategies to reduce risks for in utero surgery.

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.

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.

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.