Composite Tissue Allotransplantation (CTA)
Transplantation of solid organs has become the standard of care for many life threatening medical circumstances. Composite tissue allotransplantation (CTA) is the transfer of a composite tissue that may include skin, muscle, bone and nerve. CTA promises to be a revolutionary advance in reconstructive surgery, affording a perfect "replacement part” for tissues compromised by disease or trauma. CTA has the potential to render better cosmetic and functional outcomes for reconstruction and avoid multiple, lengthy, and often morbid operations utilizing the patient’s own tissue.
These techniques have been applied to the hand, face, abdominal wall, larynx and other body parts. Transplantation offers hope to those who suffer from severe disfigurement for an improved quality of life. It is the only operation that has the potential to restore near-normal appearance in patients with socially crippling facial injuries, and offer the most complete functional restoration currently available for hand amputees.
While appealing, human transplantation utilizing this approach presents many technical and medical challenges. The procedures can be costly; there is risk of rejection and sequellae from the use of immunosuppressant medications. As remarkable as the potential possibilities are for transplant recipients, there are many questions associated with the procedure. While the early outcomes appear promising, resulting in better aesthetic and functional outcomes when compared to traditional reconstructive techniques, long-term outcomes are still unclear. The ethics of facial transplantation in particular go beyond the life and death issues common to most transplant procedures and raise other issues that have not generally influenced medical decision-making processes.
The biggest hurdle for composite transplantation is overcoming immune modulation and the safe induction of tolerance to the composite tissue allograft (CTA). The necessity of immumosuppression and the potentially profound negative implications of immunosuppressants are well known and are a significant aspect of CTA. The complications include increased incidence of opportunistic infections, increased risk of malignancies, and end-organ toxicity. While there have been significant inroads and improvements in toxicity in the arena of immonosupression, this aspect remains a significant hurdle to wide spread application of the technology. Research efforts in the area of tolerance induction and minimal immunotherapy regimens would greatly reduce the risk benefit ratio of these transplants.
While successful transplantation of the composite tissue itself is relatively straight forward for the accomplished microsurgeon, there are subtler, complex technical issues surrounding composite allotransplantation. Preparation of the recipient site and donor tissues are critical and require precision. There is the potential for considerable blood loss. Surgical anatomy of the affected areas is often complex. Revascularization of the composite transplant requires microsurgical expertise for vascular anastamoses as well as nerve repairs to restore protective sensibility and motor function.
The potentially positive psychological impact of these procedures cannot be overstated. While most patients stand to gain enormous psychological benefit from replacing lost facial tissue or extremities, it is important to remember that patients undergoing all types of transplantation are affected by a number of stressors, including difficulty coping with the burden of complying with strict postoperative medical regimes, and understanding complicated issues associated with the many side effects and risks from immunosuppression. Patients may experience swings in emotion including gratitude and guilt in relation to the donor and his/her family, and may take on additional stress with self perceived responsibility for success or failure of transplantation operations.
CTA patients, particularly those undergoing facial transplant, may experience additional psychological issues as the transplant is highly visible. Patients may have difficulties integrating the transplant into existing body image and identity. In facial transplantation the differences in deficits of nonverbal communication and possible lack of improvement in facial animation may be problematic. Patients may experience difficulties dealing with the reactions of friends and family members to a different appearance. They may have fear associated with graft failure that may result in ongoing anxiety and hyper vigilance for signs of rejection, coupled with anxiety that appearance will return to preoperative levels of disfiguration, or worse, if the graft fails.
Research & Clinical Collaboration
CTA offers the possibility of restoring physical and emotional wholeness to a population of individuals who may have very few traditional reconstructive options, but because of these technical, medical and psychological challenges, a complete CTA program necessitates a multi-disciplinary approach to the broader application of the technology. The University of Texas Health Science Center in Houston has a longitudinal experience with solid organ transplantation and an experienced team of experts, including surgeons, nurses, immunologists and ethicists. MD Anderson's Department of Plastic Surgery has faculty with expertise in microsurgical transfer, hand and facial surgery, as well as research experience in CTA.
The goals of this joint effort include basic science research as well as clinical applications of composite tissue transplantation reconstruction of defects of the face, hand and trunk that will be undertaken with Institutional Review Board (IRB) approval. This collaboration is in progress and is targeted to provide refinement of the basic science and technical aspects of CTA, outcomes assessments of these techniques and as advancements in immunosuppressant therapies progress, pave the way for the application of composite tissue approaches to the management of complex facial and extremity injuries and deformities.
MD Anderson Cancer Center
UT-Houston Health Science Center
For more information about composite tissue transplantation, call the MD Anderson Department of Plastic Surgery: