How Is a Failed or Compromised Skin Graft Diagnosed?
There are many reasons that grafts can fail. Scrupulous surveillance of a graft includes serial inspection of both the donor site (in autografts) and the graft (recipient) site. Such surveillance is necessary to diagnose any processes that may contribute to a graft’s failure:
● Poor vascularity.
Vascular compromise can be diagnosed by inspection for color change, diminished capillary refill, temperature, edema, and general appearance.
● Hematoma or seroma, i.e., collections of blood or fluid, respectively.
Blood or transudate (exudate, in the case of infection) can be diagnosed via aspiration with a needle. The retrieved contents are examined microscopically for red blood cells, white blood cells, and bacteria (via a gram stain). The aspirate also can be cultured for sensitivity testing of any positive bacterial growth. Aspiration also allows the therapeutic benefit of reducing separation between the graft and the wound bed.
● Infection of graft site.
The most common infectious organisms are methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus, or Pseudomonas.
If infection is suspected, diagnosis is via cultures from the graft site, retrieved to identify any infecting organism with subsequent testing for its sensitivities to several antibiotics.
● Mechanical shearing.
The most common cause of graft failure is movement, which dissociates any new blood vessel growth (neovascularization) into the graft, depriving it of oxygen and nutrients. This complication causes fluid collection between the graft and the graft site bed (hematoma or seroma), further separating the graft from the bed. Immobilization is accomplished by appropriately dressing the graft site.
Hypertrophic Scarring (Keloid Formation)
All grafted areas will scar to some extent, and a scar is not deemed “mature” until a year after grafting. Any scar that is raised above skin level is considered hypertrophic. Such keloid formation is diagnosed via simple inspection.