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October 26, 2005
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While the prospect of replacing an amputated hand with composite tissue allotransplantation has generated much interest and excitement in the medical community as well as general public, some have questioned the ethical validity of such a treatment. As a treatment, hand transplantation offers no prolongation of life, yet comes with the risk of death, casting doubt on whether this procedure upholds the principle of primum non nocere (first do no harm). What the procedure does have to offer is the potential for an improved quality of life for those living with amputations, a potential which has yet to be proven conclusively. As with many other innovative and experimental procedures, the issues of scientific validity, risk/benefit ratio, and patient/donor consent must be considered in determining whether hand transplantation should be accepted as a valid form of treatment.
Hand transplantation does not involve any novel surgical techniques. The process of attaching a hand to the human body had already been established through the successful practice of limb replantation. The novelty of hand transplantation lies in the fact that an allograft is used instead of an autograft, leading to issues of rejection and immunosuppression. Researchers pursuing hand transplantation were encouraged by the fact that all components of the hand (including tendons, skin and muscle) had already been successfully transplanted individually into humans and have shown prolonged survival.
Full limb transplants in animal studies, however, did not prove as promising. In experiments done on baboons and rhesus monkeys, only two out of 23 transplants were rejection free after 200 days. It should be noted that these studies used cyclosporine as the immunosuppressant, which has since been generally replaced by more effective agents. A study with pigs utilizing more modern immunosuppressants such as mycophenolate mofetil (MMF) and FK-506 found that five of nine subjects survived without rejection for 90 days, at which point the study was terminated. Even when rejection did not occur, complications of the immunosuppression treatment such as pneumonias and septic arthritis resulted. While 90 days without rejection is not a failure, it certainly does not provide much insight into the long-term survival of such grafts, leading some to question whether the treatment is ready to be tried on humans. Ready or not, there are currently twenty human patients who have received hand transplantations, 19 of which remain in good health (the longest survival is over three years). These human successes have generated much positive publicity and have been used by some researchers as justification for further human experimentation.
Still, three years does not represent long-term survival, and others have proposed a moratorium on human hand transplantation until the current human studies and more animal studies prove the potential for long-term success.
The risks of hand transplantation are similar to the risks for other forms of organ transplantation followed by immunosuppression. The potential complications of prolonged immunosuppression include increased risk of infection, increased risk of malignancy, and toxicity of immunosuppression leading to nephrotoxicity, neurotoxicity, gastrointestinal toxicity and diabetes. Eighty percent of organ transplants result in infection, which is the cause of 40% of post-transplantation deaths. In addition, the risk of cancer following kidney transplantation, which is similar to hand transplantation in the dosage of immunosuppression used, increases 4-18%. While the recipients of hand transplantation would be put on similar dosages of immunosuppressants, it should be noted that unlike many vital organ transplant recipients, the recipients of hand transplantation are likely to be healthy at the start of treatment. In addition to the risks associated with immunosuppression, hand transplantation carries the risk of failure necessitating re-amputation.
A transplanted kidney has a ten-year survival rate of only 40-50% with a half-life of 7.5-9.5 years. There is little reason to believe that a transplanted hand, with its highly antigenic skin component, will survive much better than a kidney. Thus, immunosuppressant toxicity, increased susceptibility to infection and malignancy, and the potential for graft failure all pose substantial risks for a patient seeking hand transplantation.
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Although hand transplantation offers no life-saving ability, its benefits can be measured in the improved quality of life of its recipients. Factors to gauge the success of a transplant include the revascularization of the limb without rejection, the return of functionality, sensation, and proprioception, and the acceptance of the new hand as a natural body part. With the exception of the first hand transplant case, in which the recipient required re-amputation of the transplant due to noncompliance with the rehabilitation and immunosuppression therapy, all subsequent recipients have reported high satisfaction, low morbidity, and no mortality. In the two U.S. cases conducted at the Jewish Hospital in Louisville, Kentucky, the recipients regained movement within one week, and temperature, pain and pressure sensation by the first year. The first Louisville recipient can localize touch on the thumb, ring, and small fingers (middle and index fingers are reversed). Both recipients (at 36 months and 12 months post surgery) can tie shoelaces, dress themselves, turn the pages of a book, throw a ball, and write. The Carroll Test, a measure of hand function utilizing 33 tasks scored by two independent observers, found that the recipients of hand transplants showed more functionality than those with prosthetic devices. In addition, the Carroll Test scores for recipients of hand transplantation mirrored the early scores of recipients of hand replantation.
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Hand transplantation carries with it many of the same life-threatening risks of vital organ transplantation, but without the life-saving or life-prolonging benefits that other such procedures offer. The question that remains is whether the potential benefits of hand transplantation outweigh the potential risks. This question cannot be easily answered in an objective manner, and certain individuals may have different motives for drawing their own conclusions. Certain researchers, for example, may be motivated by the thrill of being the frontrunners in an innovative field. Certain patients, on the other hand, may be motivated by an uninformed hope for a miracle treatment. Unlike prescription drugs, new and experimental surgical procedures do not require approval from a body such as the FDA. Instead, patient autonomy has been the legal precedent, allowing such decisions to be made by the patients themselves in giving their informed consent, enabling them to decide based on their own values whether to proceed. The improved quality of life offered by a hand transplant is a highly subjective value; a new hand may mean different things to different people. However, with a complex and experimental procedure such as hand transplantation, some remain skeptical about whether the patients' consent is truly informed.
In order for patients to give their informed consent, it is vital that they have a good understanding of the potential risks of the procedure, a realistic depiction of the possible benefits, and knowledge of alternative treatments. In order to achieve this, many have proposed the use of an independent patient's advocate to serve as a mediator between the patient and the physicians. Even with patient consent, however, surgeons are held by the principle of primum non nocere to not operate unless they feel that the patient will benefit. In order to assure this, researchers must clear their procedures with an Institutional Review Board at the local level and should be open to peer review by the surgical societies at the national level. While there is strong evidence supporting the risks associated with immunosuppression, opinion about the benefits of hand transplantation remains inconclusive. A poll of senior hand surgeons found that 21 out of 23 would not personally undergo hand transplantation for a unilateral amputation. The benefits of this procedure have to be further proven before it will gain wide acceptance.
The hands are among the most expressive parts of the human body and play an important role in body image and sense of identity. The psychological state of potential recipients must be taken into account when deciding who should get a hand transplant. Potential recipients must be able to deal with the psychological assimilation of a foreign hand as their own, as well as the risk of losing their hand for a second time due to rejection or failure. The recipient of the first hand transplant had falsified his story of hand injury and was subsequently noncompliant with his immunosuppression and rehabilitation program leading to graft rejection. In order to avoid such situations in the future, it has been proposed that potential recipients undergo psychiatric evaluation of their social history, history of compliance with medical treatment, emotional and cognitive preparedness for transplantation, and decision-making capacity. In addition, assessments should be made of their body-image adaptation after amputation, impact of amputation on their identity and relationships, level of adjustment to hand loss, and conception of what receiving a donor hand would mean. Qualities indicating a good candidate for hand transplant are a history of good psychological adjustment, lack of psychiatric comorbidity, and good quality of social support. The psychological importance of the hand in the perception of body image can also be evaluated at the level of the donor. In the donation of hands, the symbolic wholeness of the donor body is compromised. Realizing the importance of maintaining bodily integrity, the first team to transplant a hand attempted to restore the appearance of the cadaveric donor through the use of prosthesis. At this experimental stage, it is unclear whether this factor will make it difficult to gain consent for the donation of human hands. In its search for participants, the Jewish Hospital received some offers from parents who were willing to donate one of their own hands for children who had lost a hand to amputation, but cadaveric donors were used in both cases.
For some, the answers provided about the validity and potential benefits of human hand transplantation do not justify further experimentation. Due to the non-vital nature of the procedure, the urgency for making the treatment available now is lessened. It has been proposed that the procedure should be put on hold until better and safer forms of immunosuppressants are developed, or until more conclusive evidence on the benefits and viability of the grafts are accumulated from the current trials. At the same time, there are many patients who are ready and willing to face the current risks in order to receive a new hand. In the end, open and public discussion and analysis must find a balance between caution and innovation in order to determine whether this experimental procedure will proceed
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Copyright © 2005 Brown University.
This article posted November 12, 2005.