Hard-to-Heal Equine Wounds Push Vets
By Jessica Tremayne
Posted: Jan. 10, 2012, 3:05 p.m. EST
By definition, a hard-to-heal wound hasn’t healed despite several treatment attempts and multiple approaches. Equine practitioners say they’re always open to trying something new, especially when a lingering wound can mean euthanasia for a patient or months of ineffective or slow healing.
“If you take 10 people, you’ll get 10 opinions on how to treat wounds,” says David Levine, DVM, Dipl. ACVS, clinical associate at the University of Pennsylvania’s New Bolton Center in Kennett Square, Pa. “Just about any treatment has a 60 to 70 percent chance of working, but the best option is closing the skin, if possible. Even if the skin doesn’t survive, the biological Band-Aid provides good results.”
Dr. Levine says proud flesh or excessive granulation is a common problem presenting with equine patients, a condition other species don’t get.
“There are theories as to why proud flesh occurs, but none help in resolving the problem,” Levine says. “We have to remove or trim this tissue, use topical products to get rid of it and apply a skin graft.”
Lower leg wounds tend to be the most frustrating to heal, says Dean Hendrickson, DVM, MS, Dipl. ACVS, director and professor at the Colorado State University veterinary teaching hospital in Fort Collins, Colo.
“There is less underlying tissue to support wound healing [in lower limbs], more tension, poor blood supply and more movement,” Dr. Hendrickson says. “These all add up to more possible failures. Infection, however, is one of our biggest challenges in wound care.”
Bacteria limit wound healing, Hendrickson says, and foreign material such as rocks, dirt, sticks and dead bone all contain organisms that promote infection.
“Even suture encourages infection,” Hendrickson says. “This needs to be removed whenever possible. Horses should be considered contaminated in all cases; it is the environment the animals are kept in. Dogs and cats that live indoors are often taken care of. Since horses live outside, their wounds are often overlooked.”
Any wound located near a joint or tendon sheath is a serious concern, says Jennifer Brown, DVM, Dipl. ACVS, of Surgi-Care Center in Tampa, Fla.
“Penetration into a joint, tendon sheath or other synovial structure can be life-threatening,” Dr. Brown says. “I have lost horses to the smallest wounds that went into a synovial structure that resulted in sepsis. In evaluating wounds, this is the most significant factor. Synovial structures should always be evaluated when the wound is in the region of one. When tendons or ligaments are damaged, they can also be life- and performance-threatening, so they are a primary concern when doing repair.”
When it comes to blood loss, a 1,000-pound horse can lose four gallons, or 40 percent, of its supply and survive, according to the American College of Veterinary Surgeons. These types of wounds, however, are uncommon, says Brown, who serves as a Veterinary Medical Assistance Teams member.
“I have only treated a few very severe wounds in which the horses lost [gallons] of blood,” Brown says. “The horses did survive, though. Some of the most horrible-looking wounds actually heal up quite well. It is often the small wounds in the wrong location that can be fatal—not because of blood loss, but because they involve a synovial structure.”
A New Option to Aid Healing
Since September, Avalon Medical Ltd. has offered RediHeal, an anti-microbial cotton candy-like substance that the company says replicates the body’s response to wound healing.
The company says RediHeal provides a healing scaffold physically similar to the microstructure of fibrin, which is the basis of a blood clot. The nanofiber structure imitates fibrin and traps blood platelets, allowing the formation of a wound cover that supports the healing process.
“Treating serious animal wounds is a $300,000 million annual industry,” says Todd Nelson general manager at Avalon Medical in Stillwater, Minn. “The problem is many of the products marketed to veterinarians aren’t efficacious, or they might have some beneficial properties such as infection prevention, but they don’t speed healing. This product does both.”
The boron-based biological glass is laced with trace elements zinc and copper for soft tissue repair reacting with the body’s fluids, releasing elements that stimulate the body to generate new blood vessels. This improves the blood supply to the wound, allowing the body’s normal healing processes to take over.
“General practitioners need to be considered when companies think about marketing wound treatments,” Nelson notes. “Primary care doctors need treatments that don’t require special training or equipment so they can keep treatment in-house and maintain affordability to clients.”
The product can be used on equine and small animal patients. Avalon is working on packaging the proper dose of RediHeal for the substantially larger, average equine wound. The product’s antimicrobial properties are especially beneficial in the typical equine environment, according to Nelson.
“The product works best with wet wounds,” Nelson says. “If a veterinarian wants to treat a wound that isn’t healing properly, debriding the affected area before applying the product will yield best results. It takes about three treatments to treat a single wound,” Nelson says. “No allergic reactions or inflammatory response has been documented and the product will sit on the shelf longer than a Twinkie if isn’t exposed to liquid.”--JT
Veterinarians say disinfecting a wound is standard practice after evaluation. After suturing, or if suturing isn’t an option, bandaging is a traditional next step for keeping the wound as clean as possible.
Bandaging a horse is a practical option if the wound is confined to a limb—and most often a lower limb, says Erika Wierman, DVM, of Rood and Riddle Equine Hospital in Lexington, Ky.
“However, because the distal limb of a horse is prone to excessive granulation tissue, bandaging can be critical for applying the needed pressure to the granulation bed,” Dr. Wierman says. “In addition, properly applied bandages can reduce contamination and help prevent infection. It should be noted that bandaging should only be done by an experienced person, as an excessively tight or improperly applied bandage has the potential to do far more harm than good.”
Bandaging can serve as a component to pain relief.
“In the initial phases of wound healing, bandages help keep swelling down and prevent contamination,” Brown says. “They provide wound protection, and the pressure of the bandage can cause some pain relief.”
Pain relief is a component that cannot be skimped on, practitioners report. In addition to being part of standard protocols and humane treatment, pain control helps divert the equine patient from the wound and from potentially causing more damage.
“There has always been a bit of a battle between those who argue that you shouldn’t remove all of the pain—lest the horse go sprinting off and worsen his injury—and those who feel that the physiological reactions to pain lessen the animal’s ability to heal itself properly,” Dr. Wierman says. “Ultimately we need to remember that horses are prey animals—in the wild, if you look weak you will end up someone’s dinner. Horses are often much more stoic than we realize and being sensitive to their pain is important.
“One last thing to keep in mind,” she adds. “Despite some of the negative effects of long-term treatment, we often forget that NSAIDs are not only analgesics but anti-inflammatory agents as well. Since inflammation impedes healing, proper use of these drugs can be an important component of wound treatment.”
Some practitioners say veterinarians should be more vigilant about using pain relief given the benefit it brings the patient.
“We need to improve our use of pain medication,” Hendrickson says. “Since the horses cannot tell us if there is minor pain, we often miss it. There are many better pain relievers now, and we could probably use them more judiciously.”
Products That Work
Brad Gordon, DVM, of the Equine Referral Clinic in Runnels, Iowa, says product claims that he investigates often are unverifiable, a concern when reliability and efficacy is essential to any practice.
“After being introduced to Vetericyn, a one-step cleanser and dressing, I tried it on a case that the wound wouldn’t heal,” Dr. Gordon says. “The client called and wanted more of the product after 10 days. This got my attention, and I have been using it for more than a year now. In addition to using the product on problematic wounds, I use it in surgeries. I also liked that the company was able to substantiate claims they made about the product’s efficacy.”
Treating wounds can be time-consuming and expensive, but owners need to understand that the investment is essential to healing, Wierman says. Twice daily cleaning and treating, sterile bandage materials, systemic medications and topical preparations are all key to preventing a problematic wound.
“There are dozens of preparations on the market today,” Wierman says. “The key to medical management of wounds is to keep the surface clean and prevent infection from setting in. Therefore, antibiotics are commonly used in wound-care protocols, although the time at which antibiotic therapy is instituted varies widely among practitioners.
“Topically, everything from various antiseptic scrubs to topical antimicrobial preparations and products intended to encourage healing are being used,” he adds. “One of my favorites, QuickDerm, utilized a metal ion formulation to stimulate an immune response to aid healing. We’ve also used options such as plasma and amnion to supply healing factors to the wound. The choice of treatment depends highly on the veterinarian’s experience, the nature and age of the wound, and the stage of healing that it is currently in.”
As in topical preparations, adjunctive therapies are ever-evolving.
“Hyperbaric therapy is receiving more and more attention these days,” Wierman says. “We are beginning to accumulate better information about how and why it might work to speed recovery. Shockwave and therapeutic ultrasound are other options for stimulating the body to heal itself.”
Platelet-derived growth factors is a biological treatment some practitioners swear by. David Jolly, DVM, of Step Ahead Farm and Training Center in Hot Springs, Ark., says, “Some veterinarians think washing a wound 10 times a day, putting bandages on and giving antibiotics is the only way to treat a wound, but using platelet-rich plasma after wound decontamination helps the body heal itself faster.”
Dr. Jolly has been treating his patients using PRP for 10 years.
“Ninety percent of wound education in veterinary school talks about how to sew up a wound,” Jolly says. “Many products that claim to help wound healing actually kill tissue they hope to heal. We need to start thinking more about how to treat equine patients biologically. I use PRP and bandage the wound, then change in three or four days. The sooner PRP is used, the more time that can be shaved off of healing. This product helps heal wounds open to bone level to skin level in 16 to 23 days.”
The platelets Jolly uses are derived from a disease-free herd. About 20 mLs of the PRP is applied to the wound and is reapplied as the wound healing evolves.
“Lack of blood supply is the big reason wounds don’t heal properly,” Jolly says. “By reintroducing growth factors to the damaged area, the body regenerates faster.”
Laser therapy is another modality practitioners can utilize in treating hard-to-heal wounds. Kim Segal, owner of Laser Stim Inc. in Plano, Texas, says D3LT therapeutic system safely and painlessly achieves a depth of tissue penetration 10 times greater (up to 2.0 inches) than any other available.
“The laser can be used immediately after the injury presents to the practitioner and every other day afterward until it is healed,” Segal says. Each session lasts approximately 15 minutes. The laser stimulates healing and reduces recovery time by 25 to 50 percent.”
|Laser Treats a Difficult Wound|
This horse kicked up, his back legs landed on a wire fence and he could not get off. The extra skin was removed surgically—therefore, a large wound was exposed. The veterinarians wanted to euthanize the horse, so the owner called Kim Segal, owner of Laser Stim Inc. in Plano, Texas. Segal said she allowed the blood to drain naturally, which was due to the laser treatment. The owner also used water to clean the wound after Segal was finished treating it, re-wrapped it and placed telfa pads, then later gauze, over the wound.
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