Wound Healing: Bandaging And Beyond
Posted: Nov. 1, 2011, 9:00 p.m. EDT
An Australian Shepherd faced a degloving injury after his coat was caught in a track hoe.
Photo Courtsey of Chad Schmiedt, DVM.
Primary care veterinarians don’t always have equipment to care for severe wound cases, and owners might hesitate to call on a specialist in a down economy. So primary care veterinarians often are looking for new and economical options.
“Regenerative medicine is an area veterinarians should be investigating,” says Jeff Wood, DVM, co-owner of American Animal Hospital Association-accredited Northside Veterinary Hospital in Hillsdale, Mich. “Compliance goes down each time a vet asks a client to come back for bandaging or additional treatment. This needs to be considered when selecting a treatment method.”
Dr. Wood says clients of his rural practice often rely on him to provide total care to their pets. When referring wasn’t a common option, he and colleague Amy Boxberger, DVM, chose to run a proactive and progressive practice to better serve patients and clients.
“Ten years ago we started using ACell Inc.’s MatriStem, a sterile, freeze-dried pig bladder bio-scaffold device we can apply in multiple areas of practice, including wound healing,” Wood says. “The product comes in a sheet or powder form. It has antibacterial properties, decreases inflammation and increases vascularization for site-specific regeneration.”
The company says the scaffold consists of an intact epithelial basement membrane and naturally derived bioactive molecules, growth factors, peptides and collagens that assist the body in the regeneration of tissues.
“The initial cost of the product can sometimes be a shock to clients,” Wood says. “But when I explain that it means fewer bandage changes and trips to the office, the possibility of a shorter treatment time and likelihood of the most cosmetic result, they’re on board. The product can solve the wound tension problem experienced in some cases and can even be used on eye injuries.”
The bio-scaffold can be used for eye injuries as well, Wood says. The product goes on the cornea instead of a contact lens, and then a third-eyelid closure is used. The product also can be placed on exposed tissue in de-gloving injuries where skin is missing. It dissolves into the tissue, creating a gelatinous material that helps in the healing process. A non-stick bandage is placed over the wound and checked every five to seven days.
“In the inflammatory/debridement stage, bandage changes can be required two or three times a day,” says Chad Schmiedt, DVM, Dipl. ACVS, assistant professor of soft tissue surgery at the University of Georgia in Athens. “Additionally, these animals frequently require daily anesthesia for serial wound debridement, wound lavage and bandaging, as well as intensive systemic support. Hospitalization of these animals is often required in the initial stages.”
Michael M. Pavletic, DVM, Dipl. ACVS, director of surgical services at Angell Animal Medical Center in Boston and author of the Atlas of Small Animal Wound Management and Reconstructive Surgery, 3rd Edition, specializes in soft tissue surgery. He is a leading authority in the subspecialty area of small animal plastic and reconstructive surgery.
He says knowing how to assess a wound from presentation through the stages of healing (or not healing) means potentially eliminating the need for skin grafts or more aggressive therapy than what is actually needed.
“There are no controlled studies for dressings or for topicals,” Dr. Pavletic says. “Sometimes, companies show wounds at various stages of healing, claiming their product aided in the healing process. But a veterinarian with extensive wound-healing experience knows that the wound, given proper care, would have healed to the same extent using a different product or on its own in the same time frame.
“Veterinarians need to keep in mind there’s no magic solution out there,” Pavletic continues. “If a wound hasn’t healed in several weeks or months, you’re wasting your time. Close it with one surgical procedure (graft/skin flap).”
Dr. Schmiedt says that in the repair phase of the wound, owners need to bring pets to the practice every few days, making bandaging a dedicated process.
“The first technique is patience,” Schmiedt says. “I’m always amazed at the ability of wounds to heal. Understanding the normal timeline and knowing when, how and whether to intervene or not is critical. If there is an underlying reason that wound is there, that should be identified and addressed.”
According to Steven Swaim, DVM, MS, professor emeritus at Auburn University in Alabama and author of “Small Animal Bandaging, Casting and Splinting Techniques” and “I Wanna See a Veterinarian,” a lingering foreign body is a common cause for delayed healing.
“A foreign body in tissues brings in the factor of tissue intelligence,” Dr. Swaim says. “In other words, the tissue is smart enough not to heal until the foreign body is removed. Infection with an unusual organism is often a cause of non-healing. A thorough work-up needs to include histopathologic examination, microbiologic examination of tissues, radiography of the wound area and special techniques as indicated, e.g. fistulography.”
Some practitioners say owners’ lack of approval for preferred, continued treatment is a hurdle they have to deal with and work around.
“The most difficult part of hard-to-heal wounds is owner constraints and the fact that dogs and cats can destroy any progress we make pretty quickly,” says Gretchen Stauch, DVM, associate at Terrell Veterinary Clinic in Austin, Texas. “Owners are less likely to continue with a plan if they foresee that it isn’t working, if it’s expensive, or if their pet continually licks or chews at wounds, hindering progress.”
Sending pets home with proper pain medication and an Elizabethan collar is mandatory for bandages to stay intact, Pavletic says.
“No wound patient should leave the practice without an E-collar,” Pavletic says. “It doesn’t make the client happy when the animal immediately destroys the work done to repair a wound.”
Hard to Heal
“The saliva from pets’ mouths can cause infection as can the general environment they live in—dogs outside and cat litter boxes,” Dr. Stauch says. “Wounds that must stay covered often require multiple bandage changes to avoid infection, but at the same time, keeping some wounds constantly covered delays normal healing.”
Solving the mystery behind a languishing wound isn’t always simple, but Schmiedt a logical explanation always exists.
“There is always a biological basis for why a wound won’t heal,” Schmiedt says. “If a wound is stuck in the inflammatory and debridement stage, then something is preventing it from moving onto the repair phase. Usually this is dead or necrotic tissue that needs to be removed, infection or inappropriate wound care.
“If a wound is stuck in the repair phase with a granulation bed that will not contract and epithelialize, this is usually because the tension is too great for the myofibroblasts, there is infection or inappropriate wound care. Identifying that biological problem and correcting it is critical. The hardest obstacle in wound healing is wounds that form because of an underlying problem, like pressure sores or decubitus ulcers.”
Pain management should be part of the wound care process from the point of presentation, says D. Tim Crowe Jr., DVM, Dipl. ACVS, emeritus, Dipl. ACVECC, FCCM, chief of surgery and critical care at Regional Institute of Veterinary Emergencies and Referrals in Chattanooga, Tenn.
“If the wound is fresh upon presentation, versus partially healed or infected, alters the course of action, but making sure the animal is as pain-free as possible is No. 1,” Dr. Crowe says. “Lidocane and other sedation should be used. Local pain blocks should never be injected in an already infected wound, but they’re preferred for new-wound pain control.”
Crowe says epidurals are excellent ways to almost immediately manage pain in animals with severe wounds.
“Efficacious pain management is a critical part of wound care, especially in the acute stages,” Schmiedt says. “I take a balanced approach, combining NSAIDs, opioids and topical analgesia. The trick is to effectively control the patient’s pain without overwhelming him, as many pain medications will also have side effects.”
Proper nutrition ties in with pain management when examining proper wound care, specialists say.
“When an animal is comfortable, it has a sense of well-being,” Swaim says. “With this comes a presence of appetite. Thus, it follows that nutrition is taken in by the animal and nutrients are present for the building blocks of the healing process.
“Chemical analgesics are a part of pain control postoperatively and there are many options for this, such as Fentanyl patches, intravenous morphine drip, wound lavage with analgesics and others. Bandaging is also a part of providing pain control and comfort. Thus, a properly applied bandage is important in wound management.”
If an animal is in too much pain to eat or if it was in poor nutritional health when it presented with the injury, experts say expediting a return to proper nutrition, or continued nutrition, is necessary immediately after cleaning and stabilize the injury. This can mean a feeding tube and/or IV therapy.
“A delay in healing can be expected when an animal is anxious or in pain and therefore not eating,” Pavletic says. “Changes to the gastrointestinal tract can occur and complicate healing when an animal isn’t eating. The issue of nutrition can determine the type of suture and suture material to use.”
Sometimes there’s just not enough skin to replace what was lost when an injury occurred, specialists say. When this happens, stretching techniques and grafts could be used.
“To stimulate open wound healing or to get tissue healthy enough for a reconstructive procedure, I have found use of topical healing stimulants to be helpful (e.g. acemannan, tripeptide copper compound and maltodextrin). I use these in an alternating seven-day regimen,” Swaim says.
“Use of a skin expansion technique has been helpful in closing wounds, especially on the distal limbs where skin for reconstruction is at a premium,” Swaim adds. “The adjustable horizontal mattress technique using monofilament suture, sewing buttons and fishing weights has been very helpful in consistent distal limb wounds quickly.”
Plotting the steps for wound healing and closure should be done as soon as the animal is made comfortable.
“Skin stretching is a strategy we use with regularity before and after a wound closure,” Schmiedt says. “We use Velcro strips you can buy from a hobby store; one side is affixed to the skin with superglue and suture and the other stretches across the wound. The idea is that the skin will gradually stretch over a period of days and this new skin can then be used to close the wound. Dr. Pavletic wrote this technique up.
“We also use skin grafting relatively frequently. Generally, this technique is employed after a granulation bed is established and can dramatically reduce the time for a wound to be closed. This is used most commonly on large wounds on the trunk and limbs.”
Negative pressure wound therapy, or vacuum assisted closure, has been used in small animal and equine medicine for a decade, gaining interest in the 18 months since KCI Animal Health began marketing the V.A.C. product to veterinarians. Now, more than 20 veterinary schools and 80 practices have used the therapy.
“A vet should consider using it when presented with any non-superficial wounds, incisions that are at risk for complications or when wanting to maximize the take of flaps and grafts,” says Thomas Lawhorn, MS, senior marketing concept manager at KCI Animal Health in San Antonio. “V.A.C. therapy helps promote wound healing. Potential economic benefits are reduction of hospital time—up to 50 percent—and it can help reduce the need for frequent bandage changes and accompanying sedation.”
Bryden Stanley, BSc, BVMs, MA CVSc, MVetSc, Dipl. ACVS, assistant professor at Michigan State University in East Lansing, Mich., says she has used negative pressure wound therapy in more than 70 cases—including a rhinoceros—in early stages of treatment shec then takes reconstructive measures, if necessary.
“Wounds that are managed inappropriately can slow healing,” Dr. Stanley says. “This could mean non-compliance by the owner, but it can also be because the veterinarian didn’t recognize what caused the wound and didn’t debride it enough or tend to it properly. When using this therapy on dogs, I use it intermittently. But cats don’t like the start and stop of the machine, so I use it on them for longer durations.”
Stanley also uses sugar, honey, collagen replacement, topicals and foam dressings.
“I like to use topical products that will enhance care in different stages of wound healing,” Stanley says. “I tweak phases on each patient, depending on their healing time.”
Fad or Effective?
When veterinarians have used the tried-and-true products and techniques that owners will allow, they often wonder about efficacy of new, untried therapies.
“We are constantly bombarded by new therapies and associated dramatic claims of efficacy,” Schmiedt says. “All too often, those claims are unsubstantiated or exaggerated. Amazingly, wounds often heal in spite of all the garbage we throw at them.
“That said, I am using more topical EDTA or silver-based products (Tricide, Silvalon, Silvaklenz, Molecular Therapeutics) in the inflammatory/debridement stage or if infection is present. We commonly use VAC therapy on wounds in the repair stage or after grafting. And Dogleggs has designed some great custom bandages for dogs with difficult-to-bandage wounds.”
Enagic, a Japanese company, sells machines that uses an anti-bacterial charcoal system to filter contaminants and chemicals like chlorine from tap water, creating Kangen water. Crowe swears by it.
“Kangen water has been used in Japan for more than 30 years,” Crowe says. “The water gets rid of microbes, viruses and bacteria on the wound after 30 seconds. I use it to flush wounds.”
Crowe also uses Assisi Loops by Musculoskeletal Therapies for Animals (MTA) before bandaging wounds, saying the products cut healing time by increasing blood flow to the injury.
“Assisi uses post-magnetic field therapy and helps speed up and complete wound healing,” Crowe says. “You can use each loop about 90 times. The treatment time is about 15 minutes for each procedure. It is non-invasive and there are no side effects. After only seven days of healing, the wound looks more like it’s at 14 days into healing.”
Other veterinarians feel more confident using biological therapy options for wound care.
“Platelets or growth factors can be used to stimulate healing,” Pavletic says. “Veterinarians can spin down blood and apply it to the wound or inject it into joints. No well-controlled studies have been conducted using this method.”
Specialists say that although wounds can try a practitioner’s patience, existing options can assist or even expedite healing. Hope springs eternal for a method that can reduce pain, speed healing and prevent infection.
“I look forward to further development of wound management as a specialty in veterinary medicine, e.g. further growth and development of the Veterinary Wound Management Society,” Swaim says. “I also look forward to more research at veterinary colleges in the field of wound management to develop new and better techniques to treat wounds.”
“I removed a round-cell tumor from the lateral aspect of the front right paw of a 95-pound, 9- year-old American bulldog named Bulldozer,” says Gretchen Stauch, DVM, associate at Terrell Veterinary Clinic in Austin, Texas.
“Even though I felt confident in my closure of his surgical wound, the day I took his bandage off he split open his incision when he bore weight on the limb. I tried about five days of frequent bandage changes with wet-to-dry bandage applications each time and didn’t feel that we were achieving any success.
“I decided to try the Avalon Wound Packing product on Bulldozer. On day zero, his wound was an approximately 1-inch-diameter circular wound with mildly purulent granulation tissue present. I started him on seven days of Simplicef orally, cleaned the wound with saline, and applied the wound packing product. I then covered the wound with one piece of square gauze and wrapped with cast padding, Vetrap and Elastikon tape.
“Five days later, I rechecked Bulldozer and only 1/4-inch granulation tissue could be seen; the rest was new skin formation. I applied the product again, wrapped it in the same fashion and rechecked five days later. At that time, the wound had only a very small pinpoint area of visual granulation tissue. I kept the bandage off, had the owner apply topical triple antibiotic cream at home twice a day, and within one day the wound had completely closed.”
“An older Australian shepherd presented with a degloving injury on his back after his coat was caught in a track hoe,” says Chad Schmiedt, DVM, Dipl. ACVS, assistant professor of soft tissue surgery at the University of Georgia in Athens.
“The problems we faced here were a dramatically large wound and severe systemic manifestations of the injury. The dog needed very intensive systemic support and wound care. In the end we treated it like any other wound and it went on to heal, but only after a significant amount of energy and expense. We employed topical sugar, skin stretchers, topical Tricide, wet-to-dry bandages and did a primary closure using close suction drains. Then it became infected, opened back up, and we did it all again.”
“A cat presented with half of its face torn off,” says Michael M. Pavletic, DVM, Dipl. ACVS, director of surgical services at Angell Animal Medical Center in Boston.
“The eye was intact but the eyelids and nose were off and hanging by its neck. We assumed it was a car fan-belt injury. I was able to reattach everything and the cat was fine.
“There’s a certain amount of gratification when you can fix an animal and return it to normal function. Pain control was a major factor in this case and taking measures to prevent infection.”
“A 14-month-old Labrador retriever required complete facial reconstruction,” says Steve Swaim, DVM, MS. “The owner was a senator from Georgia, and he owned a helicopter. He was going to take the dog for a ride. The helicopter had landed and the engines were running with the rotors all going, that included the tail rotor. The dog kept running out and barking at the tail rotor. Each time he ran out to bark at the tail rotor, he got a little closer. On one trip to bark at the rotor, he decided to take a bite out of it. Needless to say, it amputated his nose about 2 inches in front of his eyes. We were faced with taking what was left and making a new nose for him. Bottom line, he looked more like a bulldog than a Labrador when we finished.”
Option Synopsis Advice by Steve Swaim, DVM
Bio-scaffold or cellular matrix dressings are derived from the submucosa of either the intestine or bladder. They reportedly recruit the animals’ own stem cells into the injured area where they differentiate into the tissue type of the injured area
Skin grafts are generally used on areas where there is insufficient skin to move locally or create a flap distal limb and paw areas. Skin is removed from the trunk and prepared, usually as a full-thickness mesh graft, and placed on the wound where it heals in place.
Skin flaps are generally used in areas where there is enough skin to create a flap, which retains an attachment to a blood supply as it is moved to cover a wound. Some flaps have a named direct cutaneous artery.
Thus, these flaps have a better blood supply than a random vascular patter flap. They can be made longer to reach more distant lesions and have a better chance of survival
Skin stretchers. Work has been done with the implanted stretchers into which saline is injected to expand the skin so it can be used for reconstruction. This is more common in human medicine than in veterinary medicine.
Elastic bands affixed to skin around the wound have been used to put tension on the skin to stretch it before using it to close large wounds. Suture patterns have been used to stretch skin for wound closure. Pre-sutures stretch skin around a wound so it can be used for wound closure. I have made considerable use of the adjustable horizontal mattress suture.
Two techniques requiring special equipment for wound therapy are negative pressure wound therapy and microvascular anastomosis for creating distant flaps.