Degloving Injuries in Horses:Initial Treatment      Yvonne Elce, DVM, DACVS      H             orses are prone to injury d...
Degloving Injuries in Horses: Initial Treatment                                                   The injury should always...
Degloving Injuries in Horses: Initial Treatment                                         of splints when extensor          ...
Degloving Injuries in Horses: Initial Treatment      shoulders. Healing can occur without primary repair, but healing     ...
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Pv0811 elce degloving injuries in horse -initial treatment


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degloving injuries in horse : initial treatment

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Pv0811 elce degloving injuries in horse -initial treatment

  1. 1. Degloving Injuries in Horses:Initial Treatment Yvonne Elce, DVM, DACVS H orses are prone to injury due to contact with various of the wound, a few horses with complete disruption of extensor objects and structures (e.g., fences, stalls, wires). Many of tendons develop a stringhalt-like gait. these injuries are degloving injuries, which often damage a Systemic medications should be given before addressing the large area of skin and the underlying tissue and muscle, usually wound. Tetanus prophylaxis should be administered. If deep tissues without extensive damage to joints, bones, or organs. such as tendon or bone are exposed, antimicrobials (intravenous, Possible treatments, including medications, are being explored intramuscular, or regional) can be administered. Bacterial or for beneficial effects. Therapies involving growth factors, platelet- fungal cultures are not normally indicated. The need for antimi- rich plasma, and shock waves have recently been examined, so crobials depends on the wound and the deeper structures that clinicians should continually review the current literature regarding are involved. If no synovial structures are involved and adequate new treatment options.1,2 drainage can be provided, administration of systemic antimicrobials may not be necessary, but treatment depends on the clinician’s Distal Limb Injuries assessment of the wound. If administration of antimicrobials is Degloving injuries usually occur on the distal limbs, exposing warranted, broad-spectrum agents should be used and can be bone or tendon. The skin is removed in a proximal to distal direction, given systemically or regionally through regional limb perfusions. leaving a distally based skin flap. Because the blood supply to the Pain and antiinflammatory medications are always indicated for limbs flows in a proximal to distal direction, distally based skin initial wound management. Phenylbutazone (2 to 4 mg/kg) is often flaps lose blood at the proximal aspect. Wounds with a substantial given intravenously or orally. circumference may interfere with the superficial blood supply to Once the wound has been assessed, it should be anesthetized the skin. Primary debridement and repair are strongly recommended locally, cleaned, and debrided. Local anesthesia can be provided to reduce the area that will require healing by second intention. through regional nerve blocks proximal to the laceration or a Keys to successful repair include providing adequate drainage ring block immediately proximal to the laceration. A ring block and relieving tension in the skin. can be applied subcutaneously and is quick and practical. If When assessing a distal limb injury, it is important to recognize regional nerve blocks are performed, the location of the lacera- the involved structures and predict the course of healing. The tion dictates which nerves should be blocked. Intravenous chem- choice of treatment can depend on determining whether the blood ical restraint, such as either romifidine with butorphanol or supply has been interrupted, whether movement will interfere detomidine with butorphanol, should be used. During work with healing, and what resources will be available to assist with on the hindlimbs, butorphanol should be included to provide healing. It is important to realize that although degloving injuries some analgesia and increased safety if xylazine is used for seda- can appear extensive, they usually heal well with sufficient treat- tion because xylazine alone may be associated with hyperreactivity ment and time. in the hindlimbs. Romifidine is preferred by some clinicians Degloving injuries are more common on hindlimbs than because it may cause less ataxia than xylazine and detomidine at forelimbs. These hindlimb injuries usually are dorsal and involve similar sedation levels for hindlimb procedures. Many wounds the extensor tendons. These injuries do not require apposition to can be treated using standing sedation and nerve blocks, which underlying structures for the patient to regain full function.3,4 can prevent disruption of the repair during recovery from However, the fetlock may need initial support in extension until the general anesthesia. With standing sedation, safe wound debride- patient adjusts its gait or the tendon heals to underlying tissue. If ment and repair depends on the patient’s attitude and the num- the patient knuckles dorsally at the fetlock, the repair can abruptly ber of staff members who can help provide restraint. If safety separate at the edges of the skin. Support can be provided with a of the veterinarian and patient cannot be ensured, general anes- cast or splint (incorporated into a bandage) on the plantar aspect thesia can be administered intravenously at the farm or an equine of the limb from the point of the hock to the foot. After fibrosis | August 2011 | Compendium: Continuing Education for Veterinarians® E1©Copyright 2011 MediMedia Animal Health. This document is for internal purposes only. Reprinting or posting on an external website without written permission from MMAH is a violation of copyright laws.
  2. 2. Degloving Injuries in Horses: Initial Treatment The injury should always wound closure greatly in- be examined in detail to creases the chance of suc- ensure that synovial cavities cessful closure. Alternating or flexor tendons are not tension-relieving patterns involved; involvement of with a simple interrupted these structures requires re- pattern or short runs of a ferral to an equine hospital simple continuous pattern for treatment beyond su- reduces the amount of su- perficial wound care. After ture in the wound while water-soluble jelly or moist relieving tension in the skin. gauze is placed in the wound A tension-relieving pattern to prevent further contam- can be chosen based on ination, the hair around the personal preference. Stents wound edge can be clipped can be incorporated to help (FIGURE 1). The wound should distribute pressure and pre- be lavaged with sterile iso- vent the suture from cutting tonic fluid such as saline or through the skin. Stents canFIGURE 1. A degloving laceration of a hindlimb lactated Ringer solution. be cut to size from rubber FIGURE 2. The laceration in Figure 1 aftershowing severed extensor tendons and an Substances that can be toxic tubing, Penrose drains, or debridement and primary repair. Note theexposed cannon bone. Sterile lubricating jelly to tissues (e.g., nitrofura- extension sets. One tension- extensive meshing of the skin on both sideshas been placed in the wound while the zone, undiluted povidone– relieving technique is to of the repair to relieve tension and providesurrounding hair is clipped. (Courtesy of Dr. drainage. Tension-relieving mattress sutures iodine) are not recom- mesh the skin using full-Margaret Mudge) with tubing as stent can also be seen. mended. The addition of thickness stab incisions in (Courtesy of Dr. Margaret Mudge) antibiotics or antiseptics to staggered rows parallel to the fluid therapy is not strongly recommended because the efficacy of edges of the skin (FIGURE 2). these additions is doubtful.5,6 Any additives should be extremely This allows expansion of the skin, relief of tension, and good dilute because concentrated solutions have been shown to be drainage of these often-contaminated wounds. In addition, toxic to cells.5–7 Excessive pressure may drive contaminants into meshing of the skin can prevent formation of a large subcutaneous deeper tissue. Lavage using a 60-mL syringe and an 18-gauge hematoma or seroma that could mechanically separate the skin needle achieves ideal pressure but is time-consuming; constant from underlying tissue. Theoretically, it would be preferred to lavage through an 18-gauge needle attached to a fluid set and a mesh the skin on either side of the wound to avoid causing further 1-L bag of fluids is appropriate, and the bag can be easily held by vascular compromise to the skin flap in the wound. However, an untrained assistant. Use of a dental water jet has also been this is often not possible, and meshing of the skin flap represents described for providing pulsatile lavage.8 a viable and practical alternative, accomplishing many goals Highly contaminated tissue can be sharply excised. Large simultaneously. If a large subcutaneous dead space is present, a blood vessels can be ligated. The ends of extensor tendons can be Penrose or closed suction drain should be placed unless the skin debrided by simple excision of a small portion of the free end. If is meshed. periosteum is missing or bone is scored, the area can be gently Portions of devitalized extensor tendons may become chronically debrided with a curette or bone rasp. The edges of the skin can be infected and behave similar to bony sequestra, preventing complete freshened by sharp removal of a thin edge. Obviously dead skin healing, causing persistent drainage, and resulting in unhealthy should be removed; otherwise, as much skin as possible should granulation tissue. Therefore, exposed edges of extensor tendon be left intact and removed later, if necessary. should be debrided during initial treatment. Exposure of bone— Even when skin is expected to die, it can be sutured to provide especially disruption of periosteum or scoring of bone—by a a biologic bandage until it has died. Suturing decreases the ten- degloving injury should also be considered a risk for develop- dency of the flap to contract. By the time that nonviable skin is ment of a sequestrum. Disruption of the blood supply as well as ready to slough or be removed, granulation tissue may be present infection must be present for a sequestrum to develop. Clinical under the skin. If tendon or bone is exposed, protecting it with signs of a sequestrum can appear 4 to 8 weeks after injury; the skin until granulation tissue forms can help keep it clean and client should be informed of this at the initial examination. To moist. However, the client should be informed that the repair help prevent sequestrum development, damaged bone or tendon will appear to fail. The edges of the skin should be apposed in a ends should be debrided at initial treatment. tension-relieving pattern using large-gauge, monofilament, non- Bandaging or casting is important during initial treatment, absorbable suture (0, 1, or 2, depending on the patient’s size and but bandaging may be overused thereafter. Casts or cast bandages the thickness of the skin). Various techniques can be used to can enhance initial healing by (1) decreasing motion in areas relieve tension in the skin. Adequately relieving tension during where there is tension on the wound edges or (2) being used | August 2011 | Compendium: Continuing Education for Veterinarians® E2
  3. 3. Degloving Injuries in Horses: Initial Treatment of splints when extensor used to facilitate closure. It is difficult to return the skin to its Suggested Reading tendon function has been original position without excessive tension even if no skin has been lost. Bandages are used to lost. Ventral wounds are prone to formation of seromas or hema- • Articles on wound management in prevent impediments to tomas after repair, possibly compromising the viability of the The Veterinary Clinics of North healing, such as contami- repair by separating the skin from underlying tissue and increasing America: Equine Practice 2005;21. tension in the skin. Use of an abdominal bandage can help prevent nation after treatment and • Equine Wound Management. formation of edema or a this but may hold purulent discharge against the skin. If used, 2nd ed. Stashak TS, Theoret CL, hematoma.7 Once granula- abdominal bandages must be changed daily to prevent maceration of eds. Hoboken, NJ: Wiley-Blackwell; tion tissue has formed and the skin due to excessive moisture. All of these factors can make 2009. important underlying struc- repair difficult. Therefore, providing ventral drainage and relieving tures are covered, bandages tension on the skin are very important. may no longer be necessary Several techniques can help manage abdominal degloving in- and may promote excessive formation of granulation tissue.6 juries. Once the skin and tissue have been cleaned and debrided, Primary closure results in a more cosmetic outcome; however, if the skin flap can be extensively meshed using a #10 scalpel blade. it cannot be achieved, various types of skin grafts can be used This can greatly expand the skin flap and provide adequate drain- immediately or in the future to speed healing and reduce scar or age along the entire wound. An alternative method is to use a fibrotic tissue formation.9 walking suture pattern to attach the skin flap to the underlying tissue along the length of the skin flap, gradually moving the edge Other Degloving Injuries of the skin flap toward the intact edge of skin. Drains should be While many degloving injuries occur on the distal limbs, other placed at various intervals to allow drainage from a contaminat- areas of the body can be affected. The difference in healing between ed wound, and tacking sutures can help resolve dead space. Oth- wounds on the distal limbs, proximal limbs, and body is well estab- er methods can be used if they reduce tension on the skin and lished.10,11 Because of basic physiologic differences in wound healing, encourage drainage. The patient’s movement should be restricted wounds on the body and proximal limbs of horses are better able to help prevent dehiscence during healing. to contract and heal without excessive granulation tissue.10 The front of the chest and the shoulders of horses are prone to degloving Proximal Limb Injuries injuries. Large degloving injuries of the ventral or lateral abdomen Degloving injuries regularly occur on the front of the shoulders can occur when horses fall or try to jump an obstacle. and chest. These high-motion areas are prone to dead-space When assessing proximally located wounds, it is important to accumulations and loss of serum or blood. Therefore, owners determine whether underlying structures (e.g., joints, peritoneal should be informed that although repairs of high-motion areas cavity, brachial plexus, mediastinum) have been affected and to are prone to repeated failure, healing is commonly successful. In the administer broad-spectrum systemic antimicrobials (in most cases) initial healing period, exercise restriction is important regardless to prevent infection of important underlying structures. Although of the method of repair. Reducing tension in the skin and providing degloving injuries are treated in a similar fashion regardless of adequate drainage are crucial to successful wound repair. Achieving their location, there are some important differences when proximally these goals with any degloving injury can reduce the healing time located wounds are treated. Large wounds on the abdomen and and enhance the quality of the repair compared with healing by chest wall can involve muscle, resulting in substantial loss of serum; second intention, which may require more time for full return to therefore, affected patients should be monitored for protein loss. function. The use of vacuum-assisted healing for large areas of In addition, chest and abdominal wounds may cause substantial degloving is a potential advancement in managing these wounds, pain and discomfort, requiring aggressive pain management. but achieving a seal with this method can be difficult in high- motion areas of the body. In these areas, tension-relieving suture Abdominal Injuries patterns with or without stents are recommended and placing The anatomy of the blood supply to proximally located skin flaps may drains or creating mesh incisions is crucial to avoid formation of be more complex and, therefore, less well understood. Degloving seromas. Walking or tacking suture patterns can be used to injuries of the abdomen usually occur in a cranial to caudal reduce dead space and relieve tension, but excessive amounts of direction, possibly interfering with the blood supply, which flows suture should be avoided if a wound is severely contaminated. in a cranial to caudal direction. If a degloved subcutaneous layer Adequate drainage is important not only for successful repair but maintains its blood supply, the chance of maintaining the health also for preventing infection inside the wound and down the of the skin flap greatly improves. As with distal limb injuries, fascial planes into the mediastinum. Systemic antimicrobials are suturing a skin flap that is likely to die can have value. Large skin indicated if contamination is severe. flaps from the ventral abdomen must be assessed for viability and contamination. Adequate tissue debridement and suturing can Conclusion be difficult with the patient standing if the skin flap is directly Degloving injuries in horses remove large flaps of skin and under- ventral; if necessary, a rapid-acting intravenous anesthetic can be lying tissue, usually on the distal limbs, ventral abdomen, | August 2011 | Compendium: Continuing Education for Veterinarians® E3
  4. 4. Degloving Injuries in Horses: Initial Treatment shoulders. Healing can occur without primary repair, but healing 156 cases (1994-2003). Vet Comp Orthop Traumatol 2008;21(4):358-364. time can be reduced and cosmesis can be enhanced through primary 5. Redding WR, Booth LC. Effects of chlorhexidine gluconate and chlorous acid-chlorine repair of the skin flap. These benefits can be obtained even if the dioxide on equine fibroblasts and Staphylococcus aureus. Vet Surg 1991;20(5):306-310. entire skin flap does not survive. Reducing tension in the skin 6. Berry DB 2nd, Sullins KE. Effects of topical application of antimicrobials and bandaging on healing and granulation tissue formation in wounds of the distal aspect of the limbs and ensuring adequate drainage are the keys to successful repair in horses. Am J Vet Res 2003;64(1):88-92. of degloving injuries. 7. Dart AJ, Dowling BA, Smith CL. Topical treatments in equine wound management. Vet Clin North Am Equine Pract 2005;21(1):77-89. References 8. Wilson DA. Principles of early wound management. Vet Clin North Am Equine Pract 1. Monteiro SO, Lepage OM, Theoret CL. Effects of platelet-rich plasma on the repair of 2005;21:45-62. wounds on the distal aspect of the forelimb in horses. Am J Vet Res 2009;70(2):277-282. 9. Toth F, Schumacher J, Castro F, Perkins J. Full-thickness skin grafting to cover equine 2. Morgan DD, McClure S, Yaeger MJ, et al. Effects of extracorporeal shock wave therapy wounds caused by laceration or tumor resection. Vet Surg 2010;39:708-714. on wounds of the distal portion of the limbs in horses. JAVMA 2009;234(9):1154-1161. 3. Belknap JK, Baxter GM, Nickels FA. Extensor tendon lacerations in horses: 50 cases 10. Miragliotta V, Lussier JG, Theoret CL. Laminin receptor 1 is differentially expressed (1982-1988). JAVMA 1993;203(3):428-431. in thoracic and limb wounds in the horse. Vet Dermatol 2009;20(1):27-34. 4. Mespoulhes-Riviere C, Martens A, Bogaert L, Wilderjans H. Factors affecting out- 11. Theoret CL. The pathophysiology of wound repair. Vet Clin North Am Equine Pract come of extensor tendon lacerations in the distal limb of horses. A retrospective study of 2005;21(1) | August 2011 | Compendium: Continuing Education for Veterinarians® E4©Copyright 2011 MediMedia Animal Health. This document is for internal purposes only. Reprinting or posting on an external website without written permission from MMAH is a violation of copyright laws.