Intestinale Innervationsstörungen: Anatomische Grundlagen und Diagnostik

Histopathological insights into intestinal innervation disorders require the knowledge of the anatomical topography and structure of the enteric nervous system (ENS). The ENS of the human colon is composed of intramural nerve meshes located in different layers of the intestinal wall (plexus musculares, plexus myentericus, plexus submucosi, plexus mucosi). A differentiated visualization of the components of the ENS is achieved-by enzyme- and immunohistochemical methods. In comparison to cross-sections, wholemount preparations of the intestinal wall allow a two dimensional demonstration of the network-character of the nerve plexus and preserve the anatomical in-situ conditions. A complete histopathological diagnosis of the ENS requires full-thickness biopsies or resected specimens, as an assessment of the entire plexus layers is achieved only by this procedure. The establishment of reference values by means of morphometrical studies of ENS contributes to an objective and standardized histopathological diagnosis. Aganglionosis, hypoganglionosis, intestinal neuronal dysplasia and heterotopias are considered to be the most acknowledged forms of intestinal innervation disorders. In addition, degenerative changes of enteric nerve plexus, visceral neuropathies and a disturbed homeostasis of enteric neurotransmitters are described. Recently, a pathogenetical significance for functional intestinal motility disorders has been attributed to interstitial cells of Cajal (ICC). The ENS and ICC play a major role in mediating and coordinating gastrointestinal motility and therefore shoud be taken into account in clinical disorders of the intestinal motor function.