Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)
Skin grafts are an excellent modality used to reconstruct wound located on the limbs and other areas of the body
With ideal wound conditions, 95 to 100% survival of the skin graft is expected
After healing takes place, the skin graft should provide a durable covering over the wound
Definition of a skin graft
- A skin graft is a piece of skin that has been totally removed from the body and placed on a wound. Blood vessels in the wound bed will quickly grow into the underside of the skin graft, thus bringing it back to life. If the blood vessels cannot grow quickly enough into the the underside of the skin graft, the graft will die. For this reason the wound must be adequate to nutritionally support the graft and the surgeon must very carefully prepare the skin graft so that vessels will be able to grow into the graft.
Indications for skin grafts
- Skin grafts are used for wounds that are caused by
- traumatic accidents
- oncological surgery (tumor removal)
- thermal burns
- chemical burns
- vesicant burns - injected medications such as chemotherapeutic medications or some injectable anesthetics
- The procedure has the advantage of requiring only one surgery once the wound bed is adequately prepared for grafting.
Contraindications for skin grafts
- Skin grafts frequently do not "take" (die) in the following cases
- radiation has been administered to the area prior to surgery
- over bone
- over tendons and ligaments
- poorly vascular wound beds
- high motion locations that cannot be immobilized
- infection in the wound
Types of skin grafts that are used to repair wounds
- Full-thickness skin grafts are most commonly used in dogs and cats. This involves removing the a piece of skin and removing the fat from the underside of the skin. The donor site must have enough surrounding loose skin so that the incision can be closed. The survival ("take") of a full-thickness skin graft is the same as a partial-thickness skin graft.
- Partial-thickness skin grafts skin grafts involve shaving a very thin layer of skin off the donor site. No hair will grow from this skin graft because the hair follicles are in the deeper layers of the skin. The donor site will heal on its own and does not involve closure of an incision. This type of graft donor site can be more painful, as the raw donor site will have many exposed nerve endings that need to heal over with time. The indication for partial thickness skin grafting is for cases in which a dog has massive skin loss (especially a burn victim) and there is limited normal skin that is available to be used for skin grafting.
Phases of healing of a skin graft
- Imbibition: the small blood vessels on the under side of the skin graft soak up fluid (serum) from the wound bed,which provides oxygen and nutrients during the first 2 days after surgery.
- Inosculation: to "inosculate" means to "kiss". Small blood vessels (capillaries) in the wound bed meet up (kiss) and connect with cut vessels of the skin graft. At this time blood begins to circulate in the skin graft and provide it nutrition. Inosculation typically occurs within 48 hours after surgery, depending on the condition of the wound bed.
- Revascularization: small capillary blood vessels bud and grow into the capillary vessels of the skin graft like a snake would slide down a tunnel, thus providing a great source of blood to the skin graft. Revascularization of the graft takes place from day 4 to 7 after surgery.
Wound preparation and skin grafting procedure
- Skin grafting requires a fastidious bed to provide an excellent "take" of the skin
- A wound bed that is ideal for a skin graft is granulation tissue (pink red healing tissue), muscle or fascia over a muscle.
- If the wound bed does not have an ideal surface for skin grafting, the procedure will be delayed until a healthy granulation tissue bed has developed. This may take about 7 to 10 days. For example if a skin tumor has been removed from a limb, the wound can be covered with a bandage and the grafting delayed until granulation tissue is present. The bandage will need to be replaced daily until skin grafting is performed. Similarly, if a dog sustains a wound due to trauma, the grafting will be delayed until healthy granulation tissue is present.
- If the granulation tissue is excessive, it will be trimmed down to the surface of the edges of the skin and the grafting procedure is delayed for four days.
- On the day of the procedure your pet will be anesthetized and a site will be selected from which a skin graft will be collected. This site typically is the side of the abdomen or chest region, as there is abundant skin that can be safely removed without ill effects to your pet.
- As the skin graft is being elevated the fat will be carefully cut off the under side of the skin.
- Small holes will be made in the skin graft to allow fluid to escape from beneath the flap. The accumulation of fluid under the graft will prevent separate the skin from the granulation tissue and prevent the ingrowth of blood vessels into the graft.
- The skin graft is stapled or sutured over the wound (see photo left) and the limb is bandaged.
- After surgery, it is imperative that the grafted are is bandaged and supported with a splint to prevent motion at the graft site.
- The first bandage is typically kept in place for about four to five days after surgery. Care is taken when changing the bandage so that the skin graft is not pulled off the wound bed with bandage material that may be adhered to the skin.
- In the photo right (4 days after surgery), the dressing layer that is stuck on the graft is not removed, rather triple antibiotic ointment is applied over this layer and the limb is rebandaged.
- By seven days after surgery, the graft should be well secured to the granulation tissue bed and all layers of the bandage can be removed.
- The skin graft in the photo right is seen 18 days after surgery. Approximately 99% of the graft has survived and the dog is doing very well.
- Skin grafts provide a thin covering over distal extremities, therefore are very cosmetic.
- Hair growth on the skin graft may be sparse, which may be related damage to the hair follicles during collection of the skin graft. The hair usually can be oriented in the appropriate direction to match that of the native coat of the limb.
Care at home
- Limit activity for 3 weeks after surgery
- Keep the bandage dry
- Check the toes for swelling and coldness if the graft site is on a limb (while the bandage is on)
- Return to your veterinarian at the scheduled times for bandage changes
- After the bandage is no longer needed, cover the graft site with a sock (if the graft site is on a limb) for a period of 3 to 4 weeks to prevent your pet from licking and chewing at the site. If needed, an Elizabethan collar may be recommended to prevent self-mutilation
- With an ideal wound bed, about 95 to 100% "take" of the skin graft is expected.
- Survival of the skin graft is dependant on restricting your pets activity, especially during the first week
- Skin grafts frequently do not grow hair, but provide a durable covering over the wound (see photo right of a skin graft 7 weeks after surgery).
- Guille AE, Tseng LW, Orsher RJ. Use of vacuum-assisted closure for management of a large skin wound in a cat. J Am Vet Med Assoc 2007; 230-1669-1673.
- Aragon CL, Harvey SE, Allen SW, McCrackin-Stevenson MA. Partial thickenss skin grafting for large thermal skin wounds in dogs. Comp Contin Edu Pract Vet 2004; 200-215.
- Carson-Dunkerley SA, Hanson RR. Equine skin grafting: principles and field application. Comp for Cont Education for Vet; 1997.
- Swaim SF: Skin Grafts in Swaim SF (ed): Surgery of Traumatized Skin: Management and Reconstruction in the Dog and Cat. Philadelphia, WB Saunders Co 1980, pp 423-476.
- Lees MJ, Fretz Pb, Bailey JV, Jacobs KA: Principles of grafting. Compend Contin Educ Pract Vet 1989; 11:954-961.
- Converse JM, Smahel J, Ballantyne Dl, et al: Inosculation of vessels of skin graft and host bed: A fortuitous encounter. Br J Plast Surg 1983; 29:274-282.
- Ross GE. Clinical Canine skin grafting. J Am vet Med Assoc 1986; 153:1759-1765.
- Bauer MS, Pope ER: The effects of skin graft thickness on graft viability and change in original graft area in dgos. Vet surg 1986;15(4):321-324.
- Pope ER: Effect of skin grat prparation and graft viability on the secondary contraction of full-thickness skin grafts in dogs. Am J Vet Res 1985; 46(12)2530-2535.
- McKever PJ, Braden TDD: Comparison of full- and partial-thickness autogenous skin transplantation in dogs: A pilot study J Am Vet Res 1978; 39(10):1706-1709.
- Probst CW, Peyton LC, Binham Hg, et al. Split-thickness skin grafting in the dog. J Am Anim Hosp Assoc 1983;19:555-568.
Frequently Asked Questions After Surgery
When should my dog have the first bowel movement after surgery?
- Many dogs will not have a bowel movement for the first 4 to 5 days after surgery
- Reasons that a dog will not have regular bowel movements after surgery include:
- The dog has been fasted prior to surgery
- Dogs do not eat well during the hospital stay
- They frequently do not eat well when they go home
- They are fed highly digestible food that produces little stool
- Pain medication that contain narcotics (such as morphine, fentanyl patches, and tramadol) can be constipating
- If a pet does not have a bowel movement on the 5th day of being home, a stool softener such as metamucil can be fed
- Dose of metamucil is 1 tsp per 25 Kg mixed in with each meal (canned dog food); feed immediately after mixing, as the metamucil will gel the food and may make it less palatable
My pet had surgery and will not eat. What can be done?
- Most pets will not eat their regular dog food after surgery, especially if it is kibble.
- Offer a cooked diet having a 1:1 ratio of a protein source and carbohydrate source. The protein source can be any meat (example: chicken breast, turkey breast, lean hamburger) that is low in fat and should be cooked (drain off all fat after the meat has been cooked). The carbohydrate can be pasta, potato or white rice.
- Try canned dog food; to enhance the flavor sprinkle a very small amount of garlic powder or chicken or beef broth (Chicken-in-a- MugTM or Beef-in-a-MugTM products)
- Try Gerber strained meats for babies such as the chicken, beef, turkey, or veal
- Try Hill's A/D diet available at most veterinary hospitals
- Hand feeding: place a small amount of food in the mouth so that your dog gets the flavor
- Warm the food slightly in a microwave, as the food will be more aromatic; stir the food before feeding and test the temperature on the bottom side of your wrist; it should only be luke warm.
- Remember that most pets will not eat the first day or two after they get home from surgery
- Offer smelly foods that contain fish such as tuna or smelly cat foods
- Try Gerber strained meats for babies such as the chicken, beef, turkey or veal
- Hand feeding: with your finger place a small amount of food on the roof of your cat's mouth; use a syringe to get soft food into the mouth
- Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature; it should be only luke-warm
- Some cats will only eat dry food, try kibble if your cat normally has been fed that food
- Petting and stroking your cat frequently will help to stimulate appetite
- Remember that most pets will not eat the first day or two after they get home from surgery
- Appetite stimulants such as cyproheptadine may be helpful
- If your cat refuses to eat anything for 7 days a stomach tube or nasogastric tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop
My pet is vomiting. What can be done?
- The first thing for you to discern is whether your pet is vomiting or regurgitating. Both will result in fluid or food being brought up. Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus. Regurgitation is not associated with heaving and the pet usually just opens the mouth and fluid or food will be expelled. Usually the regurgited material will be clear or brown colored fluid.
- Next is to identify the cause of the vomiting or regurgitation.
- Causes and treatment of vomiting after surgery
- When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be the case, the water should be limited to frequent smaller amounts.
- Medications such as antibiotics, narcotics or nonsteroidal anti-inflammatory medication commonly cause vomiting after surgery. In order to see which medication is causing the problem, the administration of each drug should be separated 2 hours apart. Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to. The antibiotic in some cases may be changed to a different one, or may be discontinued.
- Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days.
- An uncommon cause of vomiting after surgery is internal organ failure. Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.
- If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present. Do not ignore this sign.
- Symptomatic treatment of vomiting involves withholding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then gradually wean him/her back onto the regular diet after 3 days. In order to decrease the acidity of the stomach, Pepcid AC 0.5 mg/kg can be given by mouth twice daily for 5 days. Metoclopramide and Cerenia are good anti-vomiting medications for dogs and cats. You should always consult a veterinary healthcare professional before administering medication.
- Causes and treatment of regurgitation after surgery
- The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia. Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, called esophagitis. This results in poor motility of the esophagus, therefore water and food will accumulate in this structure. In most cases, esphagitis is self-eliminating and will resolve within two or three days.
- If the esophagitis is severe the esophagus may develop one or more strictures. A stricture is a narrowing or stenosis of the esophagus and does not allow passage of food down the esophagus, in regurgitation that lasts longer than one week. This problem should be brought to the attention of your pet's doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure, as it is done with the aide of an endoscope). If an esophageal stricture is chronic surgery is needed.
- Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent (sucralfate) and an acid blocker (omeprazole or other). Consult a veterinary health care professional if the regurgitation continues for more than a couple of days.
How do I know that my dog is in pain following surgery?
- Signs of pain include
- biting if you get near the surgical site
- grimacing (lips are pulled back and the the dog looks anxious)
- tragic facial expression
- restlessness and unable to sleep; pacing
- if abdominal surgery was done the pet will not lie down on the incision, or will continually sit up in spite of appearing very tired
- the worst pain will be for the first 2 to 3 days after surgery
What can I do to control my dog's pain?
- Narcotic medications that control pain: tramadol, butorphanol, Duragesic (fentanyl patch)
- Anti-inflammatories used to control pain: Deramaxx, Rimadyl, Previcox, or Etogesic
- If an orthopedic surgery has been done cold packing the surgical site may be helpful
- A cold pack may be a pack of frozen peas, crushed ice in a Ziploc bag, or a cold gel pack; place a thin barrier between the skin and the cold pack. An alternative to a cold pack is to freeze water in a styrofoam cup; after frozen cut the bottom of the styrofoam cup out. Cool the surgical site around the incision by rubbing the exposed ice directly on the skin in a circular pattern. Cooling the surgical site helps to numb the area.
How do I know that my cat is in pain following surgery?
- Pain is more difficult to assess in cats versus dogs, as signs can be more subtle and they usually do not vocalize when in pain
- Signs of pain in a cat include the following:
- biting if you get near the surgical site
- growling or deep cry
- not wanting to eat
- hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)
What can be done for pain at home for my cat?
- Pain medication such as buprenorphine or a Duragesic (fentanyl) patch
- Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver
- Anti-inflammatories can be used, but the dose is much less than dogs
Is it okay for my pet to lick the incision?
- If a dog licks the incision, the healing process may be delayed.
- Licking can remove stitches and cause the incision to open
- Licking can become a severe habit that is difficult to break
- Licking can cause infection as the mouth has many bacteria
- Dogs will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.
- To stop your pet from licking the following can be tried:
- Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region
- Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site
- A tee shirt can be used to cover an incision on the chest or front part of the abdomen; gather the waist of the shirt up over the dog's back and wrap an elastic band around this part of the shirt.
- A bandage or sock can be used to cover an incision on a limb; fasten the top of the sock to the dog's limb with tape.
- Bitter apple can be applied around the incision; many dogs will continue to lick after application of this topical
- Bitter Apple and Liquid HeetTM (obtain this from a drugstore...it is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision
- Antipsychotic medication in some cases is needed
Board-certification by the American College of Veterinary Surgeons
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Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree
Experience in the development of new surgical treatments
Rigorous examination by the American College of Veterinary Surgeons to ensure competency in advanced surgical techniques
Assurance that a veterinarian is a surgical specialist
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