Bite Wounds: Management and Reconstruction

Local Tissue Injury In bite wounds, shearing, tensile, and compressive forces often combine to damage tissues. Little energy is transmitted to the wounded tissues in a simple shearing injury, and tissue devitalization is often minimal. Tensile forces result in avulsion of the skin from underlying tissue. Avulsion of muscles can also occur in the deeper tissue layers, resulting in hernias and muscle devitalization. Compression of the skin by the teeth results in either puncture wounds, crushing injury, or both, depending on the shape of the teeth. Compression exerted by the broader, flatter premolar and molar teeth of dogs causes crushing injuries of varying severity. Crushing causes swelling, ischemia, and necrosis. In experimental crush injury, tissue blood flow and resistance to infection decreased in proportion to the greater amount of energy absorbed by the wound. The initial appearance of many bite wounds is deceptive, because the majority of tissue damage occurs below the skin. Bites located over the thorax and abdomen frequently penetrate these body cavities; in addition, the teeth crush, lacerate, and avulse muscle and subcutaneous fat and create large areas of dead space. This subcutaneous area is inoculated with bacteria from the skin and the attacking animal’s mouth. All open bite wounds and the vast majority of closed bite wounds should therefore be considered contaminated, meaning that they contain bacteria, devitalized tissue and sometimes foreign material. Untreated, bacteria will rapidly proliferate and invade the tissues, resulting in an infected wound.