Morphologic characteristics of primary nonperforative intestinal blast injuries in rats and their evolution to...

Five hundred and fifty Wistar rats were investigated to determine the frequency of secondary intestinal perforations after exposure to nonperforating blasts and the evolution of the morphological changes from hematoma through to necrosis and gangrene. The animals were observed at different times for a period of 14 days from the moment that the injury was inflicted. Microscopic findings showed that alterations began in the mucosal layer where they were most extensive, then spread to the submucosal layer, muscular layer, and serosal layer, respectively. Examination of the intestinal wall revealed an evolution of the injury from hematoma to necrosis to gangrene, resulting in secondary intestinal perforation. The secondary wounds had centrifugal patterns, opposite those of the original wound pathways. Based on these observations, the mechanism of evolution of primary nonperforating intestinal blast injury into secondary intestinal perforations is presented.