Cadaver skin, medically known as an allograft, is human skin transplanted from one person to another. It acts as a temporary biological dressing, providing a protective barrier over large, severe burn wounds or extensive skin defects. In some cases, the skin is processed into an acellular dermal matrix, which leaves behind only the structural scaffold. This donated tissue stabilizes patients by preventing fluid loss, reducing pain, and protecting underlying tissue from infection until the patient’s own skin can be permanently grafted.
The Human Source: Donor Eligibility and Legal Consent
Cadaver skin comes from deceased individuals who meet strict criteria for donation. Potential donors undergo a meticulous screening process, including a comprehensive review of their medical and social history. This review excludes conditions that could compromise the safety or quality of the donated tissue, such as active systemic infections or certain cancers.
Infectious diseases, including HIV, Hepatitis B and C, and syphilis, are specifically tested using donor blood samples. Individuals with positive viral markers are immediately excluded from donation. The cause of death is also reviewed, and donors whose death was due to unknown causes or certain systemic conditions are ruled out.
Legal authorization for the donation must be obtained, governed by laws like the Uniform Anatomical Gift Act in the United States. This legal framework grants individuals the right to make a legally binding decision to donate their tissues, often through pre-registration on a donor registry or driver’s license application. If the deceased had not previously registered, the next of kin is approached to provide final consent for the skin donation.
Tissue Procurement and Initial Handling
Once legal consent is secured and the donor is medically suitable, the process of tissue procurement begins in a controlled environment. Highly trained, specialized recovery teams handle the recovery under sterile conditions, often at a hospital or accredited recovery facility. These teams follow rigorous protocols to ensure the tissue’s integrity.
The skin is excised using a dermatome, a surgical instrument that removes a thin, consistent layer of the outer skin. This procedure is performed with surgical care, and the donor’s body is reconstructed to maintain a natural appearance for the family. A key factor for successful donation is the post-mortem interval, the time between death and tissue recovery.
To ensure the viability of the tissue, procurement must typically occur within 15 to 24 hours after death, depending on whether the body has been refrigerated. Immediately after removal, the tissue is placed in a sterile container with a cooling solution and meticulously labeled. Rapid transportation to a dedicated tissue processing facility, or tissue bank, is then coordinated to minimize the time the tissue spends outside a controlled environment.
Quality Control: Testing, Sterilization, and Preservation
The tissue bank transforms the raw donated skin into a safe, medically acceptable product. Upon arrival, the tissue undergoes extensive quality control, including a second round of microbiological testing for bacteria and fungi. This step ensures that no contamination occurred during recovery or transport.
Sterilization methods depend on the intended use. Viable allografts, which retain living cells, are treated with an antibiotic and antimycotic cocktail to reduce the risk of infection without killing the human cells. For non-viable grafts used to create acellular dermal matrix, a decellularization process uses chemical detergents and enzymes to strip away the donor’s cellular components, leaving only the structural collagen matrix.
For long-term storage, the allograft is subjected to one of two primary preservation methods. Cryopreservation involves placing the tissue in a cryoprotectant solution, such as dimethyl sulfoxide (DMSO), and then freezing it at ultra-low temperatures, often below -130°C, which maintains cellular viability for extended periods. Alternatively, the tissue can be preserved using a high concentration of glycerol, known as glycerolization, which preserves the tissue by reducing its water activity and providing a sterilization effect.