Key Points

Reconstructive surgery is recommended for many wounds

Wound located on the limbs may be reconstructed with skin flaps

Skin flaps are somewhat more resilient than skin grafts

Definition of a skin flap

• A skin flap is a piece of skin that has its own blood supply (i.e. still attached to the body by a major artery and vein or at its base) and placed on a wound. Because this type of flap has its own blood supply it is much more resistant to external factors such as movement, fluid accumulation beneath the flap, and infection.
• A skin graft, on the other had does not have its own blood supply. It is a thin piece of skin that was shaved off the body and placed on the wound. Small blood vessels from the wound bed grow into the skin graft over a period of one week.

Indications for skin flaps

• Skin flaps are used for wounds that are caused by
  • traumatic accidents
  • oncological surgery (tumor removal)
  • radiation burns
  • 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 flaps

• Skin flaps should not be used to repair wounds that have infection, as closing the wound too early could result in an abscess or make the patient systemically ill (sepsis).

Types of skin grafts that are used to repair wounds

• Pedicle flaps are attached to the body at their base and have blood vessels that enter into the flap at the base.
• Microvascular free flaps are detached from the body and transplanted to the wound site and the blood supply is surgically reconnected to blood vessels adjacent to the recipient wound.

Wound preparation and skin flap procedure

• If the wound is infected, antibiotics will be prescribed and wound care continued until a healthy granulation tissue bed has developed.
• If a tumor has been removed, the skin flap procedure can be performed at that time.
• In this case a cat has a wound over the front of the hock (ankle region) which was caused by a bandage that was left on the limb for about 3 weeks. Conservative efforts were made to allow the wound to heal, however after 8 weeks, the wound still was not healed, therefore a reverse saphenous conduit flap was recommended.

• This photo shows the map of the flap along with the important blood vessels that feed the flap.
• In the photo below left the skin flap is partially elevated and the blood supply that keeps the flap alive is visible.
• In the photo below right the skin flap has been elevated completely and will be transposed over the recipient wound over the hock region. The wound that results from elevating the skin flap is sutured closed, as there is ample skin in this region.

• This is the skin flap one week after surgery and the entire flap has survived and the previous wound over the hock is completely covered with healthy skin.

Prognosis

• There is a small risk that the tip of the skin flap could die off, thus a second revisional surgery may be need.
• In most cases, however, the skin flap will survive without complication.