Two years after Zion Harvey made history with a double hand transplant at Children's Hospital of Philadelphia, the limbs are so much a part of him that his brain has grown new nerve pathways to move and feel the limbs.
But his body has tried to reject the organs eight times, forcing doctors to put him on stronger immune-suppressing drugs, with all their accompanying side effects and long-term risks.
In an article published Tuesday in the Lancet Child & Adolescent Health journal, Zion's 30-member medical team present that complicated picture of successes and struggles.
Now 10, Zion was considered appropriate for the unprecedented surgery because of his unusual medical profile. The Baltimore child lost his hands, feet, and kidney function to a life-threatening infection at age 2. Two years later, his mother gave him a kidney, so he was already facing a lifetime on immune-suppressing drugs when he was evaluated to receive hands.
His replacement hands, plus ongoing physical therapy, have enabled him to write, and to feed and dress himself "more independently and efficiently" than before the transplant, the article says.
However, his stronger immune-suppressing drug regimen includes a steroid, which could harm his bones and growth over time, and an anti-rejection drug that showed signs of damaging his kidney until the dosage was reduced by adding yet another immunosuppressant.
"This case shows that having previous solid organ transplant does not automatically guarantee good short-term clinical outcomes," Marco Lanzetta, a reconstructive surgeon at the Italian Institute of Hand Surgery, wrote in an editorial in the Lancet. "At the time of the hand [transplant], the patient had no medical problems. He is now on a quadruple therapy which includes" a drug aimed at limiting kidney toxicity.
The article concludes that transplanting hands to a child can be a medical success "under carefully considered circumstances." But it also says more information about long-term results, including the psychological consequences, is needed to support broader use of hand transplantation.
"One of the reasons we published this is so families will know it's not a slam dunk. It's complicated," said lead author Sandra Amaral, director of CHOP's kidney transplant program. "While the functional outcomes are positive, this surgery has been very demanding for this child and his family."
A CHOP spokeswoman said Zion and his mother, Pattie Ray, were not available for interviews.
Two years ago, CHOP held an initial news conference with the family and released a documentary video that showcased Zion's precocious self-awareness and resilience. Last August, CHOP allowed interviews with Zion and his mother during their visit to the hospital. At that time, lead surgeon L. Scott Levin declared that CHOP intended to do "many, many more" child hand transplants, even though Zion was the world's first and only case.
On Tuesday, Levin said, "I hope in my lifetime we will do many more. Yes, more data is needed, but the only way to get it is to do more cases. I would say his case is successful. I can't say what he'll be like in 10 or 15 years. But I don't think we should wait 10 or 15 years to see."
Even in adults, limb and face transplants remain rare and controversial. Unlike major organ replacements, these body parts are not life-saving, yet patients still must take immune-suppressing drugs for the rest of their lives, raising their risks of infection, some cancers, diabetes, and other side effects.
Levin, who set up Penn's hand transplant program about seven years ago, has since led double hand transplant operations in two young women.
Other than Zion, there are only a few reports of limb transplants in youngsters: an adolescent who died of complications after getting a single limb; a conjoined twin who received a leg from the non-surviving twin; and a 1-month-old infant given a hand and arm from an identical twin who died. (Anti-rejection therapy is not needed in identical twin organ donations.)
Pediatric hand transplants "have not become a viable clinical option" mainly because of the immune suppression issue, but also because child donors are scarce. What's more, artificial hands have become much better in recent decades, Lanzetta said in his editorial.
Prosthetic hands "are very light, aesthetically appealing, and can be equipped with sensibility," he wrote.
Amaral said the specialists who are monitoring Zion's progress are learning "a tremendous amount" from him. Brain imaging, for example, revealed the new nerve pathways.
Still, she hopes that with time, his life-changing surgery will not define him.