Skin Grafts Generalities

How Skin Grafts Heal

Both split-thickness (STSG) and full-thickness (FTSG) skin grafts are avascular free tissue transfers that heal through the same three sequential phases. They differ in the speed/reliability of that process and in the trade-offs (contraction, durability, cosmesis, donor-site burden) that drive graft selection.

Shared Healing Sequence

1. Plasmatic imbibition (~first 24–48 hrs): The graft has no vascular connection to the bed and survives by passive diffusion of oxygen and metabolites from plasma exudate. Fibrin secures the graft. Close apposition and immobilization are critical; thinner grafts tolerate this ischemic period better.
2. Inosculation (~day 2–4 onward): A capillary network proliferates and anastomoses form between preexisting graft vessels and recipient-bed vessels, restoring continuity and giving the graft a pink color.
3. Revascularization/angiogenesis (~day 3–7, maturing through ~day 10–12): New vessels grow in from the wound bed while native graft vasculature regresses and is replaced. Ingrowth of recipient vasculature predominates. Afferent/efferent flow is generally restored by roughly days 8–12, though perfusion continues to evolve for weeks.

Why Thickness Affects Healing

• STSG (epidermis + partial dermis): Thinner, lower metabolic demand, revascularizes faster and more reliably — “takes” more readily on marginal or larger beds.
• FTSG (epidermis + full dermis): More tissue to perfuse across the same diffusion distance, higher metabolic demand — requires a well-vascularized bed and meticulous immobilization.

Indications: When to Use Each

Factor STSG FTSG Best for Large wounds, burns, marginal/less vascular beds, temporary coverage Small wounds needing durable, cosmetically superior coverage Graft take More reliable Less forgiving; needs excellent bed Secondary contraction Greater (more wound contraction) Minimal — preferred over joints, hands, face Cosmesis / color match Poorer, can be shiny/dyschromic Superior; better texture and pigment match Durability Less durable More durable, better sensation return Donor site Heals spontaneously; can re-harvest Must be closed primarily; limits size Typical sites Trunk, extremities, burns Face (nose, eyelids, ear), fingertips, palmar surfaces

Practical Selection Summary

• Choose STSG when the priority is reliable coverage of a large area or a suboptimal bed.
• Choose FTSG when the priority is cosmesis, durability, and minimizing contraction in a small wound at a functionally or cosmetically sensitive site with a well-vascularized bed.