Management of Specific Wounds
Uncomplicated simple lacerations are usually managed by complete closure if they are not grossly contaminated. The wound should be thoroughly lavaged and debrided as necessary before closure. If tension is present on the wound edges, it should be relieved by tension-relieving suture techniques, sliding tissue flaps, or grafts. Deep lacerations may be treated according to the same principles, depending on the extent of the injury. Damage to underlying structures (eg, muscles, tendons, and blood vessels) must be resolved before closure. If a laceration is grossly contaminated with debris, primary closure of the wound may not be indicated. Contaminated wounds may be closed with drains or treated as an open wound.
Bite wounds are a major cause of injuries, especially in free-ranging animals. Cat bites tend to be small, penetrating wounds that frequently become infected and must be treated as an abscess with culture, debridement, antibiotics, and drainage. Dog bites have a more varied presentation. Because of the slashing nature of dog bite injuries, the major tissue damage is usually found beneath the surface of the wound. Although only small puncture marks or bruising may be evident on the surface, ribs may be broken or internal organs seriously damaged. The animal should be thoroughly examined and stabilized before definitive wound care is begun. The wound should be surgically extended as far as necessary to allow a thorough examination and determination of its extent before a decision on the repair can be made. After a proper assessment, debridement can be performed. Unless en bloc debridement is performed, complete wound closure is usually not recommended because the sites are considered contaminated. Closure can be accomplished with drains, as a delayed closure, or by second intention depending on the extent of the injury.
Degloving injuries result in loss of skin and a variable amount of deeper tissue. These injuries are a result of a shear force on the skin. Sources include fan belt injuries and loss of tissue during an accident with a motor vehicle. With a physiologic degloving injury, the skin is still present but completely freed from the underlying fascia. If the injury results in a loss of blood supply to the skin, necrosis may develop later. In an anatomic degloving injury, the skin is torn off the body. Degloving injuries frequently require marked and repeated debridement. Differentiating viable and nonviable tissue may be a problem in the early wound debridement process. An attempt should be made to salvage tissue in which viability is questionable. Subsequent debridement can be used to remove any necrotic tissue. With orthopedic injuries that typically accompany degloving injuries, final stabilization may be delayed until local infection is under control.
In gunshot injuries, most of the damage is not visible. As the projectile penetrates, it drags skin, hair, and dirt through the wound. If the projectile exits the body, the exit wound is larger than the entrance wound. The amount of damage caused by the projectile is a function of its shape, aerodynamic stability, mass, and velocity. High-velocity projectiles tend to produce more damage as a result of impact-induced shock waves that move through the tissue. The shock waves create blunt force trauma that results in tissue and vascular damage.
Gunshot wounds are always considered to be contaminated, and primary closure is generally not recommended. These wounds should be managed as open wounds or by delayed primary closure. After initial assessment and stabilization of the animal, the wound may be explored to evaluate the extent of damage and to determine a plan for repair. If the projectile caused a fracture, the method of repair depends on the location and type of fracture. External fixation, bone plates, and intramedullary nails are common choices for rigid stabilization of the fracture so that the soft tissues may be appropriately managed. Gunshot wounds to the abdomen are an indication for exploratory celiotomy. Gunshot wounds to the thorax may require a thoracotomy if hemorrhage or pneumothorax cannot be conservatively managed.
Pressure wounds or decubital ulcers develop as a result of pressure-induced necrosis. Pressure wounds can be extremely difficult to treat and are best prevented. Preventive measures include changing the position of the animal frequently, maintaining adequate nutrition and cleanliness, and providing a sufficiently padded bed. Factors that predispose to pressure wounds include paraplegia, tetraplegia, improper coaptation, and immobility. Mild ulcers may be managed with debridement and bandaging to prevent further trauma to the affected site. More severe wounds require extensive surgical management. After debridement and development of a granulation bed, an advancement flap or pedicle graft may be required for closure.