A Split-Thickness Skin Graft (STSG) is a common procedure in reconstructive surgery used to repair large areas of lost or damaged skin. This surgical technique, a form of autograft, involves harvesting a thin layer of healthy skin from one area of the body and transplanting it to cover an open wound elsewhere on the same individual. The primary goal of an STSG is to quickly restore the skin’s barrier function, protecting the body from infection, fluid loss, and trauma.
Defining Split-Thickness Skin Grafts
The term “split-thickness” describes the anatomical composition of the transplanted skin layer. An STSG includes the entire top layer (the epidermis) and only a portion of the underlying dermis. Graft thickness varies based on surgical need, categorized as thin (around 0.005–0.012 inches) or thick (up to 0.030 inches).
This partial inclusion of the dermis differentiates an STSG from a Full-Thickness Skin Graft (FTSG), which includes the entire dermis. The thinner STSG has lower metabolic requirements, resulting in a higher success rate for survival, especially on wound beds with poor blood supply. While versatile and able to cover large areas, STSGs are less favorable cosmetically compared to FTSGs. The resulting texture and color may differ from surrounding skin, and the graft is more prone to shrinking during healing.
Medical Conditions Requiring STSG
Split-thickness skin grafts are frequently used when a large surface area requires immediate coverage to prevent complications. The most recognized application is the treatment of extensive burns, where large amounts of skin have been destroyed. This technique is preferred because the graft can be stretched and meshed to cover a greater expanse than the original donor tissue.
STSGs are also indicated for closing large traumatic wounds where primary closure—simply stitching the edges together—is impossible due to significant tissue loss. Other common uses include covering chronic non-healing ulcers, such as pressure or venous ulcers, that have a healthy base but have failed to close on their own. Furthermore, they are used to cover exposed muscle or fascia after surgical debridement of infected or dead tissue.
The ability to harvest a large, thin sheet of skin and the fact that the donor site can heal on its own make the STSG a practical solution for wide-area reconstruction. The rapid restoration of the skin barrier helps minimize infection risk and fluid loss, which is particularly important in severely injured patients.
The Grafting Procedure
The surgical procedure involves two distinct sites: the donor area and the recipient bed. The donor site, typically chosen from concealed areas like the upper thigh, buttock, or back, is the source of the healthy skin.
The skin is harvested using a specialized surgical instrument called a dermatome, which allows the surgeon to precisely control the graft’s thickness. A portion of the dermis is left intact at the donor site, enabling it to heal spontaneously through re-epithelialization, similar to a deep abrasion.
Once harvested, the thin sheet of skin is prepared for the recipient site. This often involves passing the graft through a meshing device, which creates small, uniform slits across the tissue.
Meshing allows the graft to expand, sometimes up to nine times its original size, to cover a much larger wound. The slits also permit fluid and blood to drain from beneath the graft, preventing the accumulation of hematoma or seroma that could lift the graft and cause it to fail. The meshed skin is then secured over the clean, prepared recipient wound bed using sutures or staples to ensure stable adherence.
Post-Operative Recovery and Care
Following the procedure, care focuses on ensuring the survival of the transferred skin and managing the healing of the donor site.
The donor site, which resembles a severe scrape, usually heals within one to three weeks as new skin cells grow over the remaining dermal layer. This area can be painful initially due to exposed nerve endings and requires careful dressing changes until it is fully healed.
The grafted site requires immobilization to allow the graft to establish a new blood supply, a process known as “graft take.” Full circulation to the graft is typically restored within five to seven days, during which time the graft relies on absorbing nutrients from the wound bed. Movement, infection, or the presence of fluid pooling beneath the graft can compromise this delicate process and lead to graft failure.
The long-term appearance of an STSG is often lighter in color, smoother, and less flexible than the surrounding tissue. The grafted area is more fragile than normal skin and may require physical therapy to maintain elasticity and prevent excessive shrinking, which can occur over a period of six to eighteen months. Patients are advised to avoid strenuous activity for several weeks.