Cord occlusion techniques for selective termination in monochorionic twins

Abstract

We wished to determine the optimal method for cord obliteration to perform selective reduction in complicated monochorionic (MC) twin pregnancies under different clinical conditions. For this purpose, we reviewed our experience and the available published literature and unpublished reports. Indications were acardiac twin pregnancy, twins discordant for fetal anomaly, and severe feto-fetal transfusion syndrome where one twin had a very poor prognosis. Data were available for the following techniques: cord embolization, fetoscopic cord ligation, laser coagulation, monopolar coagulation and bipolar cautery. Unfortunately the data are heterogeneous, incomplete and reports are only sporadic.

Cord embolization using coils or sclerosants has a high failure rate and can no longer be recommended. In 23 published cases of fetoscopic cord ligation a failure rate of 10% was reported. After successful ligation an overall fetal survival rate of 71% but a risk of preterm prelabor rupture of the membranes (PPROM) of 30% was documented. Four cases of monopolar coagulation have been published—all in acardiac twin pregnancies. 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 coagulation, all procedures were technically successful. Nine of 10 were performed under ultrasound guidance through a single port. In 2 cases, frank PPROM 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 sporadically described; the success of the procedure seems to be clearly dependant 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 meaningful comparisons of available techniques for umbilical cord occlusion. Based 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 cord ligation is reserved as backup procedure if neither of these methods are successful.