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.