7 Management of Specific Wounds Bite Wounds 174 Hygroma 234 Burns 183 Snakebite 239 Inhalation Injuries 195 Brown Recluse Spider Bites 240 Chemical Burns 196 Porcupine Quills 240 Electrical Injuries 197 Lower Extremity Shearing Wounds 243 Radiation Injuries 201 Plate 10: Pipe Insulation Protective Frostbite 204 Device: Elbow 248 Projectile Injuries 205 Plate 11: Pipe Insulation to Protect Explosive Munitions: Ballistic, the Greater Trochanter 250 Blast, and Thermal Injuries 227 Plate 12: Vacuum Drain Impalement Injuries 227 Management of Elbow Pressure Ulcers 228 Hygromas 252 Atlas of Small Animal Wound Management and Reconstructive Surgery, Fourth Edition. Michael M. Pavletic. © 2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/pavletic/atlas 173 174 Atlas of Small Animal Wound Management and Reconstructive Surgery BITE WOUNDS to the skin. Wounds may be covered by a thick hair coat and go unrecognized. The skin and underlying Introduction issues can be lacerated, stretched, crushed, and avulsed. Circulatory compromise from the division of vessels and compromise to collateral vascular channels can result in Bite wounds are among the most serious injuries seen in massive tissue necrosis. It may take several days before small animal practice, and can account for 10–15% of all the severity of tissue loss becomes evident. All bites veterinary trauma cases. The canine teeth are designed are considered contaminated wounds: the presence of for tissue penetration, the incisors for grasping, and the bacteria in the face of vascular compromise can precipi- molars/premolars for shearing tissue. The curved canine tate massive infection. teeth of large dogs are capable of deep penetration, whereas the smaller, straighter canine teeth of domestic cats can penetrate directly into tissues, leaving a rela- tively small cutaneous hole. The jaws of larger dogs in Wild Animals and Bite Wounds particular can generate tremendous crushing (up to 450 psi) and shearing forces, and the canine teeth can Bite wounds from black bears (Ursus americanus) and tear and lacerate the skin, hypodermis, and underlying the grizzly bear (Ursus arctos horribilis) are infrequent, but musculature. are most commonly seen in hunting dogs or unsuper- A struggling victim may promote additional tissue vised dogs where these bear species are most prevalent. injury while attempting to wrest free of its attacker. Small Although bears frequently attack the head and neck area, dogs and cats are at special risk since most portions of hunting dogs may be bitten (or clawed) in the trunk and their body can be completely grasped by a large dog pelvic regions, most likely when the bear lunges at a (Fig. 7‐1). In one study, male dogs weighing less than retreating dog. Tissue trauma can be massive. Coyote 10 kg presented with more severe multiple bite wounds. (Canis iatrans) attacks on dogs and cats have been reported (Miniature pinchers, Pekinese, and small terrier breeds throughout the United States as a result of their expand- were overrepresented.) Many of these victims are lifted ing range. Wolves (Canis spp.) are less prevalent and are and violently shaken by the attacker. Direct and indirect limited to selective areas of the northern United States. trauma to internal organs frequently occurs. The kidneys Both wolves and coyotes may hunt in small groups, in small animals are particularly susceptible to bite increasing the risk for a fatal attack. wounds over the back. In addition, bone fractures, joint Attacks from other large carnivores, including moun- injuries, and spinal trauma also may occur. tain lions (Felis concolor), alligators (Alligator mississip- The untrained observer can mistakenly dismiss the piensis), and crocodiles (Crocodylus acutus) are far less gravity of the bite wounds since the only obvious injuries prevalent due to their comparatively small populations may be a few puncture wounds or indentations confined and limited range. Of particular concern are bite wounds AB FIG. 7-1 (A, B) Medial and lateral view of extensive tissue necrosis to the left forelimb of a Scottie. A neighborhood pit bull attacked the dog and refused to let go of the patient’s limb. Due to extensive skin, muscle, and bone necrosis, with destruction of the carpal joint (arrows), amputation was performed. Management of Specific Wounds 175 A B FIG. 7-2 (A) Massive cervical trauma to the trachea and cervical muscles as a result of a dog fight. The patient was administered oxygen prior to anesthesia. The cervical area was prepared for surgery. Anesthetic induction was immediately followed by a cervical incision, with placement of a sterile endotracheal tube into the lacerated trachea. The gas anesthetic machine was connected to this tube. Once the patient was stable, the technician passed a sterile endotracheal tube through the larynx. The surgeon then guided the tube past the tracheal tear. (B) Surgical repair included tracheal anastomosis, thorough debridement of necrotic muscle, copious lavage, and delayed primary closure. Small puncture wounds were uncapped and locally assessed using a pair of mosquito hemostats as tissue retractors. These wounds were left open to heal by second intention. However, complete excision of small puncture wounds can permit primary closure. from wild animals, including raccoons, skunks, and bats, stable patient. (A neurologic examination would be in which rabies is an endemic problem (see Rabies and the advisable prior to using medications that could obscure Transmission of Infectious Diseases, later in this chapter). these injuries.) Blood loss, shock, respiratory distress (including laryngeal wounds, tracheal injuries, pneumomediastinum, Initial Patient Assessment pneumothorax, hemothorax, flail chest) are emergency situations that frequently require the clinician’s immedi- A complete physical exam is required. A history of the ate attention before completing the examination (Figs 7‐2 attack may help in locating the body region(s) bitten. and 7‐3). The prognosis of the patient, definitive course(s) Latex gloves must be worn during the examination and of action required, and potential complications in man- management of open wounds. aging the patient are essential to the owner’s decision regarding whether or not to proceed with treatment in the seriously injured pet. In the interim, basic life‐ A complete medical history should include the patient’s medical support procedural guidelines include the following history and current rabies vaccination status. areas of emergency resuscitation: (1) airway, (2) breath- ing, (3) cardiac function, and (4) hemorrhage control. The patient’s head should be restrained or muzzled Intravenous fluid support and whole blood would be during examination to protect the practitioner from indicated in the presence of extensive tissue trauma and injury. The hair coat must be parted and skin areas visu- blood loss. Details on emergency management can be alized. Small spots of dried blood and matted hair fre- obtained in standard textbooks. A complete blood count, quently overlie puncture wounds. Careful palpation and serum chemistry profile, and urinalysis can serve as observation may demonstrate muscle tears or hernias. baseline data for the seriously injured patient. Keep in mind that Elizabethan collars also can be useful in shield- Treatment of hemorrhage requires (1) recognition of the condi- ing veterinary personnel from being bitten, especially in the less tion, (2) control of further blood loss, and (3) intravenous fluid aggressive canine and feline patients. support to treat the patient’s hypovolemia. In many cases, blood loss is not the result of an obvious spurt- ing artery. Internal hemorrhage can be difficult to quantitate. Care must be taken to minimize pain to the patient and Individual bite wounds may result in little hemorrhage; collec- avoid manipulating unstable fractures or spinal injuries. tively, multiple bite wounds can result in a sizeable loss of blood. Analgesics or sedation may be used in an otherwise 176 Atlas of Small Animal Wound Management and Reconstructive Surgery A B FIG. 7-3 (A) Puncture to the cervical trachea as a result of a dog bite: intraoperative view. A canine tooth created the opening that enabled air to pass into the cervical tissues, impairing the ability of the patient to breathe. Manual compression of the skin over the puncture site halted the air excursion until anesthesia and intubation could be accomplished. (B) Closure was accomplished by conservative debride- ment of the wound borders followed by placement of 3‐0 polydioxanone sutures. 1. Minimize further contamination of open wounds Fully equipped emergency units with a dedicated staff address the critically injured patient. Critical care clinicians, surgeons, prior to preparing the wound for surgery. Cover the and the anesthesiology team working in concert will give the open wound with sterile gauze sponges; sterile patient the best chance of surviving. water‐soluble gel or saline is applied to the gauze before application. 2. Liberally clip hair around each puncture wound. Systemic Effects 3. Gently cleanse the skin around each wound with warm sterile saline and a surgical preparation Multiple and severe bite wounds can initiate a systemic solution. inflammatory response syndrome (SIRS). What normally 4. Inject small amounts of lidocaine with a 25‐gauge is a regional response to injury becomes an exaggerated hypodermic needle into and around the bite wound systemic