Surgical Transplant

There are many types of transplant surgeries, from specific cell and tissue transplants to entire organs. Cornea tissue transplants for the eye were one of the first successful transplants routinely performed. A thin transparent membrane found in front of the eye, the cornea can cause blindness or clouded vision if it is scarred by injury or infection. The transplant procedure involves cutting out part of the damaged cornea and replacing it with cornea from a donated eye. Cornea transplants are relatively simple procedures because they require no reconnection of blood supplying arteries, thus removing the danger of an adverse immune response. These procedures are successful 90% of the time.

The transplantation of bone tissue was first performed in the 1890s and involved replacing diseased or injured bone with pieces of bone from donors. The modern procedure involves using donor bone as a type of scaffolding built over metal nails that immobilizes and connects the patient's remaining bone sections.

Unlike bones and the cornea, most other transplants are more difficult to achieve because they involve circulating blood and the immune system. Skin grafts for burn patients, for example, are often achieved using autografts (meaning from the self), in this case, segments of skin from other areas of the patient's own body. A flap graft begins with the partial separation of skin from its original site until adequate blood circulation is achieved, then it is completely severed and grafted onto the transplant site. This technique has a high success rate for curing scars or deformities. A full thickness autograft entails removing small pieces of all the layers of skin for transplantation; these types of skin grafts are particularly suitable for the face to achieve the least amount of scarring. A split-thickness autograft removes tissue-thin layers of skin that heal easily when transplanted. The one drawback to this type of skin graft is that the transplanted tissue usually appears reddish, which makes them more noticeable. Some skin grafts come from the skin of human donors or other animals, like pigs, and are used when large areas must be covered. Unlike the cosmetic goals of other grafts, these grafts are used primarily to stop the patient from losing fluids through the burned area and to prevent infection. Research is also underway to grow skin for grafting from a few donated skin cells.

Bone marrow transplants are often used to treat patients with blood diseases, like leukemia. The transplant procedure involves taking the tissue from the center of bones through a needle, a technique called bone marrow aspiration. The marrow may be an autograft taken from a patient while the disease is in remission and stored until they need the healthy blood cells. Bone marrow taken from other donors of the same species are called allografts. Unlike most immune responses in transplantation in which the donor's body rejects the transplant, in bone marrow allografts it is often the transplanted marrow that reacts against the host. This is known as graft-versus-host disease.