Composite Tissue Transplantation
Who would benefit from Composite Tissue Transplantation?
A composite tissue allograft (CTA) is a construct made up skin, muscle, tendon, nerves, bone and blood vessels from another human being that potentially can be transplanted to an appropriate recipient. Currently, at this time the only way to prevent rejection of this tissue is to have the recipient patient placed on immunosuppressive medication. Ongoing research in laboratories all over the world are working on ways to induce recipient patient immunological tolerance to these CTA’s to lower the immunosuppressive medication requirements or remove them altogether.
Composite tissue provides the plastic and reconstructive surgeon the opportunity to replace the exact tissue missing from the patient. At this time there are two major areas under active clinical exploration. The first is area concerns hand transplantation. There is currently no artificial device that can substitute for the loss of a complex structure like the hand. Those patients that have lost either one or both hands could benefit from transplantation. There is currently widespread support for the transplantation of those patients that have lost both hands, as there are few other options available to them. Unilateral hand transplantation remains somewhat more controversial, however multiple groups have successfully performed these transplants.
The second area is that of facial reconstruction. Facial allotransplantation may be indicated as an alternative to reconstruction with autologous tissue in those patients that have lost significant portions of their face due to causes such as massive burns, cancer resections, congenital malformations, or trauma Transplantation could be the best method to reconstruct the loss of complex specialized tissues such as the lips, nose and eyelids.
The deformity caused by massive facial burns may represent an indication for facial allograft transplantation. Often, these are relatively healthy patients with no other underlying comorbidities. The severely burned patient may represent an optimal patient population to undergo facial tissue transplantation. Patients that have lost significant tissue after trauma are also an excellent group for facial transplantation as they are also often healthy individuals. Patients with certain congenital conditions such as neurofibromatosis can also be good candidates for facial transplantation after resection of these large tumors.
The extensive facial tissue resections for the surgical treatment of head and neck cancer commonly leave a complex tissue defect. These cases would certainly benefit from the use of composite tissue allotransplantation, as it would allow restoration of the patient, possibly in a single stage. However, the current immunosuppressive protocols will hasten recurrence of primary malignancies and increase the incidence of secondary malignancies such as skin cancer or lymphoma.
Oncologic patients, though attractive for treatment with facial tissue transplantation, are not currently considered appropriate recipients. With the advent of immunotolerance protocols specific to composite tissue transplantation, may allow these patients to undergo facial allotransplantation.
Other areas that could benefit from CTA will develop in the future. One area that is currently in development is transplantation of the abdominal wall. This could be considered at the time of multi-visceral organ transplantation or as an option for those patients that have undergone multiple failed autologous attempts at reconstruction of the abdominal wall.
Patients that are candidates for composite tissue transplantation must meet certain qualifications. The patient must be healthy enough to tolerate not only the initial operation to perform the transplant but they must be able to tolerate the life-long immunosuppression needed to maintain the transplant. Patients with significant co-morbidities such as severe cardiovascular problems might not able to tolerate the initial operation while patients with a history of malignancy might be put at an undue risk of recurrence due to the effect of the medications on the immune system.
The patient will have to undergo a through psychiatric evaluation in order to ensure that they have the mental stability to undergo the transplant, recovery and maintenance of the transplant. They must have full capability to understand the risks and benefits of the surgery. They also need a social work evaluation to assess the patient’s social support network. All patients will need a significant support group to help them cope with the stresses and possible complications that could occur with a CTA transplant.
Once evaluated by the surgeons, medical specialists, social workers, transplant coordinators, and psychiatrists the patient can then be listed for the transplant.
