ABSTRACT
The developments of ultrasound imaging prenatally as well as the implementation of ultrasound screening in pregnancy in most developed countries lead to an increasing number of fetal anomalies to be diagnosed before birth. The issue of fetal treatment is raised when the anomaly is diagnosed at an early stage and when its natural history suggests that the most likely outcome is either perinatal death or severe handicap irrespective of pediatric management. Specific complications related to monochorionicity are based on hemodynamic imbalance between the twins, which are essentially normal as in twin-to-twin transfusion syndrome (TTTS) or in cases with a normal twin and its abnormal co-twin with the extreme form of the acardiac twin. Thoracic anomalies are the most illustrative to view fetal surgery in both historical and technical perspectives. Tracheal occlusion was first clinically achieved by laparotomy, hysterotomy, neck dissection, and tracheal clipping with impressive results on lung growth in a subset of fetuses but with a low survival rate.
