Feasibility of minimally invasive intrauterine fetal access in a monkey model

Purpose: We evaluated new intervention techniques and surgical instruments in a fetal monkey model to determine improvements that would be useful for early intrauterine intervention. Our findings may be helpful in the future for treating select cases of severe prenatal obstructive uropathology. Materials and Methods: in a series of experiments on 18 pregnant rhesus mon keys (Macaca mulatta) at mid trimester we assessed various endoscopic intra -amniotic access techniques as well as morbidity, mortality and possibiliti es for fetoscopy. Results: In all 18 fetuses adequate fetoscopy was possible with no maternal mortality. Of the 18 pregnancies 14 went to term with no early or late pos toperative complications. Technical improvements changed the intrauterine a ccess technique from open placement of trocars to the use of the Seldinger technique, gun introduction of needles with small caliber sheets and small caliber introduction trocars, resulting in minimal amniotic membrane separa tion. Various rigid and flexible endoscopes were evaluated for fetoscopy an d up to 3 cannulas were placed. No change in the fetal growth pattern was o bserved on postoperative ultrasound. Subsequent pregnancies occurred during this study period, and there were no acceptance problems of the newborns b y the mothers. Conclusions: New techniques have led to improved intrauterine fetal access. Morbidity mainly depends on the disruption of amniotic membranes, which ha s an important preterm role. Adapted endoscopes and other instruments offer new possibilities for fetal diagnosis and therapy in the future. Our prima te model seems to be suitable for evaluating these new techniques before th ey are used in a clinical setting.