There are reasons, of course. “These kidneys have gone through multiple rounds of insults,” says Richard Formica, a nephrologist at Yale University and the secretary of the American Society of Transplantation. He ticked them off: death of the original donor, ice, reperfusion injury when the kidney is placed back in the body, immune system-suppressing drugs that can cause kidney damage, death of the second donor, ice again, reperfusion injury again. “Few kidneys would be good enough,” he says.

In this specific case, says Veale, the kidney did seem good enough. The original donor was a young, healthy teenager, and the second donor’s creatinine levels—a common measure of kidney function—were good. Once Boyce agreed to the transplant, Veale went out to recover the kidney himself.

There he ran into another challenge. When patients receive a transplant, the new kidney usually goes into the pelvis attached to the iliac blood vessels that supply the leg. (The patient’s original kidneys in the lower back usually stay put. ) Over time, scar tissue can form. To make sure he could sew the kidney into Boyce’s body, Veale took out not just the kidney but also some of the second donor’s iliac vessels. Boyce now has tissue inside her from two donors: the kidney of the 17-year-old girl as well as the iliac vessels of the young man.

It was only the second transplant reusing a kidney Veale had ever performed; he has now done a total of three. In the entire country between 1988 and 2014, 38 kidneys were reused in transplants, along with 26 livers and three hearts, according to an American Journal of Transplantation study. (A spokesperson for United Network for Organ Sharing, the organization that matches donors to recipients in the United States, told me it does not specifically track the reuse of previously transplanted organs, so it did not have recent numbers readily available.)

The numbers in the American Journal of Transplantation study were too small to make useful comparisons between reused organs and ordinary ones. A handful of case studies have documented successful cases—though that may reflect a bias in what gets published. One case study followed a patient with a reused kidney who was still in “good health” 14 years later. Another case documented some complications—the second recipient became infected with an antimicrobial-resistant virus from the first recipient, which ultimately went away with different drugs. “Our patient eventually had a good outcome, but it was tough,” says Pradeep Kadambi, an author of that case study. “We still think we did the right thing” in offering him a reused organ.

Case studies are not clinical trials though. “I think the thing that’s really held [reusing transplanted organs] back is it’s too infrequent and too difficult to structure a trial,” says Alejandro Lugo, who published a 10-year follow-up case study of a reused kidney in 2015. In other words, there is no good data on the outcome of these cases compared to ordinary kidney transplants. Formica, the nephrologist at Yale, put it this way: “This has never been studied to what we would hold to be scientific rigor.”