Cord occlusion techniques for selective termination in monochorionic twins

We wished to determine the optimal method for cord obliteration to perform selective reduction in complicated monochorionic (IMC) twin pregnancies und er different clinical conditions. For this purpose, we reviewed our experie nce and the available published literature and unpublished reports. Indicat ions Were acardiac twin pregnancy, twins discordant for Fetal anomaly, and severe fete-fetal transfusion syndrome where one twin had a very poor progn osis. Data were available for the following techniques: cord embolization, fetoscopic cord ligation, laser coagulation, monopolar coagulation and bipo lar cautery. Unfortunately the data are heterogeneous. incomplete and repor ts are only sporadic. Cord embolization using coils or sclerosants has a hi gh failure rate and can no longer be recommended. In 23 published cases of fetoscopic cord ligation a failure rate of 10% was reported. After successf ul ligation an overall fetal survival rate of 71% but a risk of preterm pre labor rupture of the membranes (PPROM) of 30% was documented. Four cases of monopolar coagulation have been published - all in acardiac twin pregnanci es. In three cases the abdominal aorta was coagulated prior to 20 weeks and complete cessation of flow was demonstrated. In 10 cases of bipolar cord c oagulation, all procedures were technically successful. Nine of 10 were per formed under ultrasound guidance through a single port. In 2 cases, frank P PROM occurred, leading to induction of labor. The other eight fetuses were born at 35 weeks or more. Nd:YAG coagulation of the cord was much more spor adically described; the success of the procedure seems to be clearly depend ant on gestational age. In all our attempts prior to 20 weeks, we failed in only one out of 6 cases. In summary, there is little data to perform meani ngful comparisons of available techniques for umbilical cord occlusion. Bas ed on practical and technical considerations we use the following clinical algorithm: prior to 21 weeks, we attempt to coagulate the cord with Nd:YAG laser. If this is unsuccessful, or for gestations beyond 21 weeks, bipolar cord coagulation is currently our other method of choice. Sonoendoscopic co rd ligation is reserved as backup procedure if neither of these methods are successful.