Applied embryology in pediatric surgery.

The surgical correction of birth defects in the newborn is still a major challenge for pediatric surgeons. Approximately 3% of human newborns present with congenital malformations. In 1%, these malformations are so severe that immediate surgical intervention is necessary to save the affected newborns life. Morbidity remains high in some of these children with the necessity of repeated operations and hospitalizations despite a successful primary operation. As a consequence, in the United States today congenital malformations are the main cause of death in the neonatal period. This mortality shift indicates that gradually knowledge about congenital malformations lags behind the general progress clinical research has made in the surrounding fields. This is highlighted by the fact that detailed knowledge of the embryological background, the natural history and the teratology of many congenital defects is still unclear or controversial. In the past, progress in this field of research was hampered by small numbers of suitable normal human embryos of the various stages. Three-dimensional (3-D) reconstructions which are an essential component to investigate the development of structures like the foregut, the hindgut or the diaphragm, were technically difficult and time consuming to perform. Studies on abnormal development were not possible due to a paucity of appropriate embryos and young fetuses with congenital defects. However, recently some animal models have been developed applicable to embryological studies. We used these to elucidate the abnormal development of the hindgut and the diaphragm. An animal model for the study of abnormal foregut development will be available soon.