Split-Thickness Skin Grafts: When and Why Part of Your Skin Is Used to Repair a Wound

What Is a Split-Thickness Skin Graft?

Skin has two main layers: the epidermis (outer layer) and the dermis (deeper layer). A split-thickness skin graft takes the epidermis and only a partial thickness of the dermis — leaving enough of the dermis behind at the donor site that it can regenerate and heal on its own, without needing its own graft.

This is what makes STSGs different from full-thickness skin grafts (FTSGs), which remove the entire skin thickness including all of the dermis. Because an STSG takes only part of the dermis, it can be used to cover larger areas, and the donor site heals without surgery. The trade-off is that STSGs tend to look somewhat different from surrounding skin (slightly shinier, potentially discolored) compared to full-thickness grafts, which match recipient site skin better but are limited in size.

When Are STSGs Used After Skin Cancer Surgery?

After Mohs surgery or wide excision, most wounds can be closed with stitches or a local skin flap. STSGs are used when:

• The wound is too large to close directly without excessive tension or distortion of nearby structures
• There is insufficient adjacent skin for a local flap repair
• The wound is over a joint, the scalp, the lower leg, or another area where a flap is not technically feasible
• The patient’s medical condition makes a longer, more complex flap procedure undesirable
• The wound is in an area that needs to be closely monitored for tumor recurrence — leaving it more open with a graft (rather than burying it under a flap) allows easier visual inspection

How Is the Procedure Done?

Split-thickness skin grafting is typically performed under local anesthesia with sedation, or in some cases general anesthesia, depending on the size and location of the wound. Here is an overview:

• Donor site selection: The most common donor site is the outer thigh. Other options include the upper arm, buttock, or scalp (which heals particularly well and is often used for facial grafts). The donor site is chosen to minimize visible scarring.
• Harvesting the graft: A surgical instrument called a dermatome slices a uniform thin sheet of skin from the donor site. The thickness typically ranges from 0.3 to 0.45 mm (about the thickness of a credit card or less). The donor site bleeds lightly and is covered immediately with a special dressing.
• Preparing the graft: The harvested skin may be “meshed” — passed through a machine that creates a cross-hatched pattern of slits. Meshing allows the graft to expand to cover a larger area, permits wound fluid to drain through the graft, and helps the graft conform to uneven wound surfaces. Non-meshed (sheet) grafts are used on the face for a better cosmetic outcome.
• Applying the graft: The graft is placed over the wound bed and secured with sutures, staples, or tissue glue. A bolster dressing (a padded pressure dressing) is applied over the graft to hold it firmly against the wound bed and prevent shearing.
• Duration: The grafting step itself takes 30–90 minutes depending on the size and complexity of the wound.

How Does a Skin Graft Survive?

A graft has no blood supply when it is first placed. For the first 24–48 hours it survives on plasma seeping from the wound bed (“plasmatic imbibition”). Then, tiny new blood vessels grow from the wound bed into the graft (a process called inosculation and neovascularization) — typically beginning by day 3–5. By day 7, the graft is usually vascularized and considered “taken.”

For the graft to survive, it must stay firmly in contact with the wound bed and be protected from movement during this critical period. This is why dressings, bolsters, and activity restrictions are so important in the first week.

Caring for the Graft Site and Donor Site

Recovery from an STSG involves two wound sites, each with different care needs:

Graft site (recipient wound):

• The initial dressing is typically left in place for 5–7 days to protect the graft while it establishes a blood supply
• After the first dressing change (done by your medical team), keep the site moist and covered as instructed
• Avoid any pressure, shearing force, or movement over the graft for at least 1–2 weeks
• Once healed, protect from sun exposure; grafted skin can develop permanent color changes with UV exposure

Donor site:

• The donor site is painful — often more so than the graft site. It typically feels like a bad sunburn or road rash.
• The donor site is covered with a special semi-occlusive dressing (e.g., Mepitel, petroleum gauze) that is left in place while the skin regenerates from the remaining dermis below
• Most donor sites heal in 10–21 days, depending on thickness of the graft taken
• The healed donor site typically leaves a slightly lighter patch that fades over 6–12 months

What Does the Final Result Look Like?

Healed STSGs often look somewhat different from the surrounding skin:

• The graft may appear slightly shinier, smoother, or differently textured than normal skin
• Color match is variable — meshed grafts often show a “cobblestone” or lattice pattern; sheet grafts blend better cosmetically
• Color mismatch tends to improve over 12–24 months as the graft matures
• On the scalp, STSGs do not grow hair; on other areas, partial hair regrowth may occur if enough dermis was included

For wounds on cosmetically important areas like the face, full-thickness grafts or local flaps are generally preferred over STSGs because of their better cosmetic match.

When to See a Dermatologist

• Your wound after Mohs or excision surgery is too large to be closed with stitches and your surgeon has discussed reconstruction options
• You have signs of graft failure: the graft looks dark, dry, or is not adhering after the first dressing change
• Your donor site is showing signs of infection: increasing redness, warmth, swelling, or pus
• You have questions about your scar appearance or want to discuss scar improvement options after your graft has healed

Frequently Asked Questions

Will the area where the graft was taken from scar?

The donor site does leave a scar — a flat, sometimes slightly lighter patch of skin. Because the deep dermis (which contains the hair follicles and sweat glands that allow the skin to regenerate) is left intact at the donor site, it heals without needing a graft itself. The resulting scar is generally flat and fades significantly over 12 months. On the thigh, it may be a somewhat lighter patch that is easily covered by clothing.

What is a “graft failure” and how common is it?

Graft failure means the graft did not survive — usually because it failed to establish a blood supply from the wound bed. Causes include movement or shearing force in the first few days, fluid accumulating under the graft (hematoma or seroma), infection, or a poorly vascularized wound bed. Partial graft failure (where part of the graft does not take) is more common than complete failure. The rate of full take with proper surgical technique and dressing management is high — typically above 90% for well-vascularized wounds. Areas that failed to take are managed with re-grafting or wound care until healed.

How long until I can resume normal activity after a skin graft?

Activity restrictions depend on the graft location. For a graft on the lower extremity, keeping the leg elevated and avoiding standing for extended periods for 1–2 weeks is important to protect the graft. For other locations, avoid heavy exercise or anything that could shear the graft for 2–3 weeks. Your surgeon will give specific guidance based on where your graft is placed.

What is the difference between a split-thickness and a full-thickness skin graft?

A split-thickness graft includes the epidermis and only part of the dermis, allowing the donor site to heal without surgery and allowing larger areas to be covered. A full-thickness graft includes the epidermis and the entire dermis, producing a better cosmetic match and more durable result, but it is limited in size and the donor site requires surgical closure. Full-thickness grafts are typically preferred for facial reconstruction when the defect is not too large.

Trusted Resources

• American Academy of Dermatology — Skin Cancer
• Skin Cancer Foundation — Mohs Surgery and Reconstruction
• Mayo Clinic — Skin Graft

Always consult a board-certified dermatologist or surgeon regarding wound reconstruction options after skin cancer surgery. This article is for educational purposes only and does not replace professional medical advice.