HUMAN DEFUNCTIONALIZED COLON - A HISTOPATHOLOGICAL AND PHARMACOLOGICAL STUDY OF MUSCULARIS PROPRIA IN RESECTION SPECIMENS

Despite the regression of ''diversion colitis,'' temporary functional disorders after bowel continuity restoration could be caused by change s in the smooth muscle of excluded segments; however, studies on the m uscularis propria have yielded contradictory results. This study was a imed at evaluating possible histopathological changes in muscular laye rs and motility of the defunctionalized human colon. Ten patients with defunctionalized colorectum (group A) and 10 controls (group B) under went restorative or primary resection surgery. Strips were taken proxi mal to the colostomy (specimens A1) and the defunctionalized segment ( specimens A2), and from the proximal (specimens B1) and distal extremi ty (specimens B2) of resected colons. Measurements of the thickness of the muscularis propria and of the volume density of the myenteric ple xus, as well as of spontaneous motility and responses to electrical an d pharmacological stimulation were taken. The muscularis propria was t hicker in A2 than in A1 specimens (P = 0.004) and in B2 than in B1 spe cimens (P 0.007). No differences were recorded either in the myenteric plexus volume density or in colonic motility. No differences were rec orded in intergroup comparisons. As no structural or functional change s related to defunctionalization were found, clinical disorders after colorectal restoration could rather result from underlying colonic pat hology and/or incomplete distal colon resection.