ABSTRACT
Fetoscopic or ultrasonographically guided laser ablation procedures are performed for pathologically significant shunting of fetal blood flow in cases of large (or multiple) chorangioma, acardius, and TTTS. Laser surgery of pathologic vascular supply to chorangiomas428,440,441 and acardiac twins4 can result in the resolution of shunting and of fetal cardiac failure. In TTTS, which has an extremely high mortality rate of one or both twins of at least 80%, fetoscopic ablation of chorangiopagous vessels has gained acceptance as an effective treatment. Since in TTTS the system of placental vascular anastomoses is not in equilibrium, this intervention aims at rapid photocoagulation of all fetoscopically identifiable anastomoses on the vascular equator as soon after diagnosis of TTTS as possible618. (An average of eight anastomoses are seen in TTTS610,617). Infant outcomes are related to the gestational period of onset and severity. However, even in cases of severe and early TTTS, laser treatment in mid-gestation has been associated with a 68% overall survival rate, an 81% survival of at least one twin, 42-57% dual twin survival, and continuation of pregnancy for an additional 10-13-week period617. Severe neurologic morbidity/cerebral palsy rates have been reported to be from 3.4-4.3%623 to 9-13%622,654. Therefore, while perinatal mortality and morbidity with laser surgery are not insignificant, it has proved to be a very valuable mode of treatment.
