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Skin grafts — thickness, take and failure
A skin graft is tissue without its own blood supply, so it "takes" only from a bleeding wound bed; a split-thickness graft (STSG) takes easily but contracts more during healing, and a full-thickness graft (FTSG) takes less readily but looks better and contracts less.
Why it matters in the exam
Take passes through three phases: fluid absorption (imbibition) in the first 24 to 48 hours, connection between graft vessels and bed vessels (inosculation) at 48 to 72 hours, and ingrowth of new vessels from day 4 to 7. The commonest cause of failure is a collection under the graft — haematoma or seroma — followed by shear and infection; group A Streptococcus destroys a graft even with a small bacterial load. Beds unsuitable for a graft: bone without periosteum, tendon without paratenon, cartilage without perichondrium and irradiated tissue — these need a flap. A bolster dressing or negative pressure holds the graft in contact and improves take.
Primary contraction occurs immediately after harvest because of elastin, and it is greater in a full-thickness graft; secondary contraction occurs during healing because of myofibroblasts in the bed, and it is greater in a thin graft — so on the face and palm, near joints and on the eyelids full-thickness grafts are preferred. The donor site of a split graft heals by re-epithelialisation from hair follicles and skin glands within about 10 to 14 days; the donor site of a full graft is closed with sutures. For the face, a full graft is taken from behind the ear or above the clavicle to match colour. Meshing increases area and allows drainage, at the cost of a "mesh" appearance. Bilayer dermal substitutes (such as Integra) form a neodermis, and after 2 to 3 weeks the silicone layer is removed and a thin split graft is applied.
Key points
- Take: imbibition, inosculation, new vessels.
- Failure — usually haematoma or seroma.
- Thick — large primary contraction; thin — large secondary contraction.
- Face and palm — full-thickness graft.
- Bed without blood supply — flap.
Summary table
| Feature | Split-thickness graft | Full-thickness graft |
|---|---|---|
| What it includes | Epidermis and part of the dermis | Epidermis and all of the dermis |
| Take | Easy, even on a poorer bed | Needs an excellent bed |
| Primary / secondary contraction | Small / large | Large / small |
| Donor site | Heals on its own within 10 to 14 days | Closed with sutures |
| Typical use | Large wounds, burns | Face, palm, eyelids, near joints |
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Sources
- Grabb and Smith's Plastic Surgery, 8th edition (2019) — Skin grafts
- Plastic Surgery (Neligan), 5th edition (2023) — Skin graft physiology and donor sites
- British Association of Plastic, Reconstructive and Aesthetic Surgeons standards for wound and graft care, current — Graft care and dressing principles
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.