Radiofrequency driven cord occlusion for selective termination of pregnancy: evaluation in the fetal sheep.
OBJECTIVE
This study was designed to assess the ability of an ultrasound-guided radiofrequency (RF)-driven procedure to induce complete and irreversible cord occlusion using a 90 days fetal sheep model.


METHODS
Twenty 90 days gestation sheep underwent general anesthesia. The first ten fetuses were exposed under hysterotomy, and RF electrode was inserted visually in the middle of the umbilical cord and deployed. Fetuses were then replaced into the amniotic fluid and RF procedure (average target temperature of 100 degrees C during 10 minutes) was applied. For the next ten fetuses, RF electrode was inserted into the cords under trans-parietal ultrasound guidance and the same RF procedure was applied. Cord occlusion was assessed by Doppler examination (absence of cordonal flows at the end of the procedure and until fetal heart failure occurred) and by subsequent histopathological analysis.


RESULTS
Cord occlusion was always complete at Doppler examination at the end of RF procedure for the ten experiments realized under hysterotomy. No cordonal reperfusion was observed until fetal heart failure. Histopathological analysis confirmed cordonal occlusion at the site of impact. Neither cordonal rupture nor cordonal bleeding was observed for any of the ten experiments. When RF electrode was inserted under ultrasound guidance, complete occlusion could be obtained only for 6 of the ten experiments.


CONCLUSIONS
Our results suggest that RF might be an appropriate method for selective termination of pregnancy. Yet, optimal insertion of the electrode is required to engender a complete and irreversible cord occlusion, and ultrasound-guidance training seems necessary before current human application.
Morel
Olivier
O
Department of Obstetrics and Gynecology, Hôpital Lariboisière, APHP, Paris, France. olivier.morel17@wanadoo.fr
Tran
Nguyen
N
Barranger
Emmanuel
E
Foliguet
Bernard
B
Marchal
Frédéric
F
Chastant-Maillard
Sylvie
S
Judlin
Philippe
P
Villemot
Jean-Pierre
JP
Thiebaugeorges
Olivier
O
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005333:Fetus / Q000098:blood supply; D017078:Laser-Doppler Flowmetry; D023421:Models, Animal; D011247:Pregnancy; D018607:Pregnancy Reduction, Multifetal / Q000379:methods*; D012756:Sheep; D018084:Ultrasonography, Interventional / Q000379:methods; D014470:Umbilical Cord / Q000000981:diagnostic imaging / Q000502:physiology / Q000601:surgery*