Chances are you saw eight-year-old Zion Harvey's story somewhere on the news in the past few weeks and already know that a team of more than 40 surgeons, nurses, and anesthesiologists from Penn Medicine, the Children's Hospital of Philadelphia, and the Shriner's Hospital, came together to do something that had never been done before — the very first pediatric double-hand transplant in the world.
Though the expertise of the combined team resulted in a world’s first, the skills necessary to do the bilateral hand transplant procedure have been developed over the course of many years. The first successful bilateral hand transplant was performed on an adult in 1998, and Penn’s first, performed by Harvey’s lead surgeon L. Scott Levin, MD, FACS, director of the Penn and CHOP Hand Transplant Programs, chairman of the department of Orthopaedic Surgery, the Paul. B. Magnuson Professor of Bone and Joint Surgery, and professor of Surgery (Division of Plastic Surgery), was done back in 2011 on then 28-year-old Lindsay Ess.
Successful completion of a bilateral hand transplant begins with a specialized team of surgeons trained in microsurgery. The specialty involves extensive training to perform intricate procedures involving very small surgical areas, small blood vessels and nerves. Because of the specialized expertise involved in completing the procedure to date, less than 100 have been done worldwide.
Now, with the early success of the procedure behind them, the Penn-led team is looking to strengthening Harvey’s muscles through daily physical therapy sessions, and maintaining the health of the transplant. As with any transplant procedure, doctors are also closely monitoring Harvey for any sign that his body may be rejecting the hands.
Tens of thousands of organ transplants are performed in the US every year, and they routinely extend lives, but the success rates of these procedures continue to be limited by immunological rejection and other complications.
“It’s not the technical ability to do the operation; we’ve been able to do that for years,” Levin said. “But to transplant hands, and have a patient’s body accept those hands, and modulate the immune system for a lifelong requirement of drugs, that’s the obstacle that remains.”
Rejection is a risk for any transplant patient because, just as the immune system recognizes and fights viruses and bacteria, it will also recognize an organ (or hand) that isn’t native to the body. Antirejection medicines, or immunosuppressants, work to ward off rejection by essentially weakening the immune system. Though it can make patients more susceptible to illness, and therefore may be seen as an ethical concern, particularly for a child, in this latest case, Harvey had already undergone a life-saving kidney transplant four years ago and was actively taking immunosuppresants.
To help reduce the chances of rejection, doctors perform extensive tests to match both the organ or tissue donor and the recipient. The more similar the antigens are between the donor and recipient, the less likely that the organ will be rejected. Though these matching procedures help ensure that the organ or tissue is as similar as possible, no two people, except identical twins, have identical antigens.
Though some studies have suggested using stem cells may help reduce the risk of transplant, and others have identified certain variables that may decrease risk, on the whole, doctors do not currently have a way of positively identifying which patients will experience rejection and which will not.
“Determining whether a transplant will reject or not is likely influenced by many variables, including multiple genetic factors in both the donor and recipient,” said Abraham Shaked, MD, director of the Penn Transplant Institute. “While modern testing procedures can help us determine a good donor/recipient match, some patients still experience rejection, even while taking immunosuppressants. Unfortunately, we don’t currently have the ability to say which patients will reject a transplanted organ or tissue. Obtaining the information necessary to detect all the genetic variables that could factor into a possible rejection would require incredibly large, global datasets that are just not available.”
In the meantime, as researchers continue to explore new ways to match donors and recipients, and manage the risk of rejection, Harvey's story continues to inspire hope for patients of all ages, and their care teams.