Skin Flap / Skin Graft

Reconstructive surgery is indicated when:

• Wide excision of a malignant tumor — such as a mast cell tumor, soft-tissue sarcoma, or squamous cell carcinoma — leaves a defect too large for primary closure
• The wound is located over a joint, limb, or area of high skin tension where simple closure would restrict movement or fail
• Trauma or infection has caused significant skin loss after a previous surgery
• Salvaging the limb is preferred over amputation, and adequate skin coverage is required to do so

Reconstruction with a flap or graft can mean the difference between limb preservation and amputation — or between clean closure and a chronic open wound.

The technique chosen depends on the wound size, location, and the pet's available donor skin:

• Advancement or rotation flap: adjacent skin is undermined (freed from underlying tissue) and slid or rotated to cover the defect, carrying its intact blood vessels
• Axial pattern flap: a larger flap based on a named artery is raised and pivoted to cover defects at a distance from the donor site — used for limb and trunk wounds
• Free skin graft: a thin sheet of full-thickness or split-thickness skin is harvested from the trunk, perforated with small holes to allow fluid drainage, and sutured over a healthy, well-vascularized wound bed

The donor site is closed directly if possible. Bandaging is placed immediately post-operatively to protect the repair and encourage graft take.

Pre-surgical planning for reconstruction typically includes imaging (CT or ultrasound) to confirm the tumor's extent and plan margins. Pre-anesthetic bloodwork is performed, and chest X-rays are obtained when the tumor type carries metastatic risk. Withhold food from the evening before surgery. Because reconstruction is planned together with the tumor excision, both procedures are usually scheduled for the same day — so coordination of time and bloodwork results often happens in the days leading up to the procedure.

Reconstruction requires more attentive aftercare than a simple wound closure:

• Bandage changes — often every two to three days initially — to monitor graft take or flap viability; the team will teach owners to inspect the wound at each change
• Strict activity restriction for three to four weeks; the new tissue must not be stressed while it establishes its blood supply
• An Elizabethan collar at all times to prevent licking or scratching
• Pain management and, when indicated, antibiotics during the healing phase
• The graft or flap typically appears pale or slightly bruised in the first 48 to 72 hours before it "pinks up" as blood flow is established — this is normal and not a sign of failure

Scheduled rechecks allow the surgeon to assess healing and reduce bandage frequency as the wound matures.

Partial graft or flap loss is the most common complication — a portion of the transferred skin may not fully establish a blood supply and requires management. In most cases partial loss heals with wound care rather than repeat surgery. Infection, seroma (fluid pocket), and wound breakdown at the donor or recipient site can also occur. The oncologic risk — recurrence if tumor margins were not clean — is independent of the reconstruction itself and addressed by the pathology report. Despite these possibilities, reconstruction is often the factor that allows an otherwise unresectable tumor to be treated and a limb to be preserved.