Fetoscopic laser ablation of placental vessels in severe previable twin-twin transfusion syndrome.

OBJECTIVE

We undertook a pilot study to determine the feasibility and efficacy of fetoscopic laser occlusion of chorioangiopagous vessels in severe previable twin-twin transfusion syndrome.

STUDY DESIGN

A total of 35 patients were referred to the investigators with ultrasonographic findings consistent with twin-twin transfusion syndrome, posterior placental implantation, gestational age < 25 weeks, and clinical hydramnios. Placental vessel occlusion was performed with a rigid 2.9 x 3.85 mm dual-channel fetoscope and neodymium:yttrium-aluminum-garnet laser light.

RESULTS

Of the original 35 patients, 5 were eliminated preoperatively and 4 intraoperatively for various factors. The 26 treated patients had a mean gestational age of 20.8 weeks (range 18 to 24) and a mean fundal height of 36.1 cm (range 29 to 44). One patient has surviving triplets, 8 have surviving twins, 9 have a single survivor (2 neonatal and 7 fetal deaths occurred in this group), and 8 have no survivors (all had pregnancy loss within 3 weeks of treatment). The cases with survivors were delivered for obstetric indications at a mean of 32.2 weeks (range 26 to 37), having gained a mean of 11.7 weeks (range 6 to 17) in utero. Fifty-three percent (28/53) of the fetuses survived with 96% (27/28) developing normally at a mean age of 35.8 months (range 1 to 68). Thirty-three of 35 placentas were monochorionic with chorioangiopagous vessels on gross and microscopic evaluation.

CONCLUSIONS

Fetoscopic laser occlusion of chorioangiopagous vessels is technically feasible and improves the course and outcome of severe twin-twin transfusion syndrome in previable fetuses.