Histologic and embryologic studies on the innervation of the pelvic viscera in patients with Hirschsprung's disease.

On the specimens taken at autopsy from three newborns with Hirschsprung's disease and three newborns in the control group, the innervation of the pelvic organs was histologically studied. The authors found that all the pelvic organs, except for the rectum in patients with Hirschsprung's disease, preserved a completely normal innervation not only of pelvic autonomic nerve plexuses, but also of sensory nerves of spinal origin. Even in the wall of the aganglionic rectum, the extrinsic sympathetic as well as parasympathetic nerve fibers were preserved, which showed a marked proliferative change due to the absence of target nerve cells upon which they otherwise terminated. An additional embryologic study was performed upon 20 human embryos. The results revealed that the pelvic nerve plexuses were formed during the six to ten gestational week period by neural cells migrating along the pelvic visceral branches of sacral nerves, while none of these neural cells was found to enter the rectum. The enteric plexuses of the rectum were formed later by neural cells that migrated down along the alimentary tract in a craniocaudal manner. The two separate origins, the sacral for the pelvic nerve plexuses and the vagal for the enteric plexuses of the rectum, seem to be the reason why innervation of the genitourinary organs, which are located in front of the aganglionic rectum, is normal in those patients with Hirschsprung's disease.