Split-Thickness Skin Grafting

A Primer for Orthopaedic Surgeons

Benjamin C. Taylor, MD; Jacob J. Triplet, DO; Mark Wells, MD

Disclosures

J Am Acad Orthop Surg. 2021;29(20):855-861. 

In This Article

Anatomy

The STSG consists of an epidermal layer and a portion of the dermis. The epidermis, comprised primarily of keratinocytes, acts as a significant barrier to the external environment. In addition, the presence of melanocytes, Langerhans cells, Merkel cells, and nerve endings resides within the epidermis. Deep to the epidermis resides the dermis; this fibrous layer is composed of collagen, glycosaminoglycans, and elastin. Unlike the epidermis, it also contains hair follicles, sweat glands, and sebaceous glands.[1] The superficial dermis (papillary dermis) contains plexi of blood vessels and nerves that provide nutrients to the epidermis via diffusion. In addition, the stem cells within the dermal hair follicles are responsible for the re-epithelialization of skin graft donor sites. The deeper dermis (reticular dermis) contains collagen fibers that portend strength and stability to STSGs. Stability is further enhanced by the undulating surface between the epidermis and papillary dermis.

The amount of harvested dermis is dependent on the desired graft thickness. Thickness is dictated as thin (0.15 to 0.3 mm), intermediate (0.3 to 0.45 mm), or thick (0.45 to 0.6 mm).[1,14,15] A thicker graft has the advantage of being more metabolically active but portends worse nutrition diffusion. Because a healthy robust wound bed is needed for the success of the STSG, a thicker STSG should be avoided in an unhealthy wound bed, such as a chronic ulcer.

After being placed on a well-vascularized wound bed, the success of the STSG is dependent on three factors. First, imbibition must occur, allowing for the passive absorption of oxygen and nutrients from the wound bed, permitting the ischemic STSG to remain viable; ischemia may be tolerated up to 4 days.[1,16–18] Next, inosculation ensues, establishing a vascular network between the capillary beds of the prepared wound bed and the sectioned vessels on the undersurface of the STSG; this occurs approximately 2 days after placement of the STSG.[19] Finally, the revascularization period follows allowing neovascularization and/or endothelial cell proliferation into the STSG from the prepared wound bed.[1,20–23]

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