Equine Wound Healing

Transcription

1 Equine Wound Healing Michael Thomassen, D.V.M. Nebraska Equine Veterinary Clinic Horses seem to find ways to injure themselves even when many precautions are taken to make their environment as safe as possible. It is recommended to have lacerations and wounds examined by a veterinarian to determine how serious the injury is and if the wound can be sutured closed. However, there are many times that a wound cannot be sutured or the sutured wound opens up and has to heal on its own. This article will talk about the major stages of wound healing, show picture examples of a wound as it was healing and discuss what the wound may look like. Keep in mind that these wound healing periods overlap. Once you get through the article, you will be able to see a wound that we cared for earlier this year. Following a traumatic injury, the inflammatory period is characterized by the local redness, heat, and pain caused by palpation. This period can last several days to weeks and takes longer in large, contaminated wounds. The next phase is called the debridement phase. This period is characterized by large numbers of white blood cells moving into the wound. These white blood cells help to clear the wound of dead tissue and bacteria. Again, the larger and more contaminated the wound is, the longer this period lasts. The proliferation period occurs when new tissue deposition occurs. Granulation tissue is the main type of tissue that proliferates. This granulation tissue has a lot of blood vessels. You may notice that a wound that has not been bleeding much when cleaned, now will bleed when cleaned. The granulation tissue helps the wound to contract and become smaller. Proud flesh is when granulation tissue becomes excessive. Once the wound has mature granulation tissue, epithelialization can begin. When excessive granulation tissue develops, wound healing is delayed. Proud flesh can be treated with topical medication or by surgically removing the extra tissue. The epithelium is what we like to think of as skin and begins along the outer margins of the wound and progresses toward the inside of the wound. During the maturation phase, the wound strength increases and tissue production and tissue destruction occur at the same rate. And now for the interesting part of this article1the pictures.

2 The horse in these pictures is Scooter, who is a 10 year old Quarter Horse gelding that injured both of his front legs on April 15, There are multiple pictures of his legs throughout the entire healing process. You will see that the wound was repaired with sutures but unfortunately the primary closure did not stay together. There are multiple reasons for this happening and they include tension along and across the repair, poor tissue strength due to compromised blood flow and excessive motion due to its location on the body. The wounds were then treated as open wounds with both topical and systemic medications. As you will see, Scooter had a very successful outcome. The reasons for this include a very willing patient who did not need sedation for any of his treatment at home and a very committed owner. During the early stages, the wound was being cared for twice per day. As you can imagine, this was very time consuming. We were also very blessed that Scooter did not develop any serious infection from either wound. This is a picture of the initial injury which occurred on April 15, after both wounds were cleaned thoroughly and closed with sutures.

3 This is a picture of the wound on the right front leg 4 days after the wounds were repaired. There is discharge from the center of the repair. This was an indication that the repair would likely not remain intact. This is 7 days after injury. This is a picture of the right front leg. This picture shows a lot of discharge and necrotic tissue. The long process of open wound care began and included both systemic antibiotics and topical wound care. This picture is taken 13 days after the initial injury and 5 days after discharge from the clinic. As you can see, both wounds are completely open at this point. There is a noticeable change in wound appearance with healthy granulation tissue present in both wounds.

4 on May 9th, 24 days post injury. This is the first picture that shows very noticeable wound contraction. Much less discharge would be expected from a wound in this stage of healing. This picture is a close up of the previous picture. Notice the filled in, flat appearance of the left front wound. If you look closely around the perimeter of the wound, you can see new epithelium. In this picture and several of the following it shows up as a thin pale pink to white line. on May 22nd, 37 days post injury. Note the continued contraction and epithelialization of the wound.

5 on May 29 th, 44 days post injury. on June 8 th, 54 days post injury. on July 5 th, 81 days post injury. Notice now that the right is completely healed and hair is covering nearly the entire wound. The left wound is close behind.

6 on September 9th, 147 days post injury. It is hard to believe but this is truly the same horse. He is being ridden now and has no lameness from the injuries.