The Leg Bone's Connected to the Arm Bone
When a child has cancer that is slowly destroying his shoulder and arm, how do you make him all better?
The age of the child made him an ideal candidate for a procedure that would transplant one of his own growing bones.
Last summer, Tovi Kirshner's first thought was that her 3-year-old son Reuven had a pulled muscle. He was complaining about pain near his left shoulder and under the armpit when she would lift him. The pain seemed to subside after a while, but when Tovi and her husband, Neil, visited family in Chicago, Reuven awoke in the night screaming in pain.
The family — Neil, Tovi, Elisha (5), Reuven, and Avraham (2) — had recently relocated to St. Louis from Chicago, so she took him to the same pediatrician's office that had cared for the boy before the move. X-rays revealed a lesion on the left humerus, the bone that runs from the shoulder to the elbow. He had a rare bone cancer called Ewing's sarcoma. "It was the most terrifying moment of my life," Tovi recalls. "When we got back to St. Louis and to Children's Hospital, we learned it was a stage 4 cancer that had spread to his lung."
The lung lesion was removed immediately, and Reuven began a 42-week course of chemotherapy with surgery scheduled for week 12. The operation presented two big problems. One was that Reuven, at three years old, had a small skeleton, and surgery would cost him a lot of bone in his arm and shoulder. A second was that although Douglas J. McDonald, MD, professor and chief of orthopaedic oncology, frequently operates to remove cancerous bone, he doesn't often do it in toddlers.
"When we see this disease in children, usually they're teenagers," McDonald says. "When a child is 13 or 14 and almost finished growing, we can resect the tumor and easily replace the diseased bone with a prosthesis."
But a plastic or metal prosthesis is static. It can't grow as a child grows, and Reuven had lots of growing ahead. Even if McDonald had wanted to implant a rod, he couldn't have found one small enough. To get rid of the tumor, he needed to remove about two-thirds of the humerus. But in Reuven's arm that whole bone was only about the size of a ballpoint pen. Even expandable rods that can be implanted into growing children would have been way too big.
"We worried that amputation might be the only option," Tovi recalls.
But, not long after that, she received a phone call from one of McDonald's orthopaedic surgery colleagues, Martin I. Boyer, MD, associate professor, was planning a trip to Italy to learn a rare surgical procedure called free vascularized growth plate transplant.
Learning the technique would allow Boyer to move the fibula bone from Reuven's leg into his upper arm — transferring not only the bone but the vasculature as well.
"I was shocked at what they were willing to do," Tovi says. "They literally went around the world to get this done and save Reuven's arm. We're new to St. Louis, but we're convinced we're here for a reason."
Boyer traveled to Milan to watch Marco Innocenti do the procedure. "He developed the technique and has done nearly 30 of them," says Boyer. "My resident, John Carlisle, MD, and I left St. Louis on a Sunday, got to Milan on Monday, operated on Tuesday, came home on Wednesday and were back in clinic on Thursday."
Not long after the whirlwind trip, Boyer joined McDonald in an operating room at St. Louis Children's Hospital to perform the first free vascularized growth plate transplant ever done in the Midwest and one of only a handful of such operations ever done in North America. First, McDonald removed the tumor and, with it, about four inches of the boy's humerus bone, along with some of his shoulder. Then, Boyer and his team took over. Boyer, Carlisle and Kevin Lutsky, MD, made an incision in the leg, removed Reuven's fibula, and placed it in his arm.
The fibula and the tibia, or shinbone, run from the knee to the ankle. It turns out that the tibia does most of the work, in terms of supporting the leg, and people can function fairly well without a fibula. Ligaments, tendons and muscle attach to the fibula, but it bears less weight than the tibia and is much less critical to leg function. This is the key in Reuven's case — that the fibula has a reliable blood supply that can be moved along with the bone, allowing it to grow after it is transplanted and revascularized microsurgically.
"If this hadn't been a biological reconstruction, we would have had three problems," Boyer says. "We would have no joint because part of his shoulder was removed with the tumor. We would have been short of bone because two-thirds of his humerus was removed. And, if we had implanted a prosthesis, the length of his arm after the operation would have been the length of his arm forever."
That need for a functioning growth center made Reuven an ideal candidate for the surgery. After a girl reaches nine or 10 or a boy reaches 11 or 12, Boyer says there's really no compelling reason to put a child through an operation like this because they won't have a lot of growing left to do.
"In that case, you would reconstruct it with a prosthesis," he says. "You might over-lengthen the arm by however much you expect it to grow, but a surgeon probably wouldn't want to subject an almost-grown child to a second incision and the additional trauma to the leg.
Reuven's transplanted growth plate with its built-in blood supply should continue to grow. In addition, Boyer says, some strange things should happen on his X-rays in the coming years.
"A young child has the ability to remodel the graft," he explains. "If you take a fibula and put it in place of a humerus, it still looks like a fibula on an X-ray. But over time, some children can remodel the bone, so it ends up looking much more like a humerus."
And McDonald says it's likely the bone will grow and function well. Reuven may never have normal shoulder function, but fibula grafts have worked for many other patients, and most have recovered very well.
And that means when Reuven is 11, the fibula bone in his arm should be significantly longer and look very different on X-rays than it does now.
"It's amazing," his mother says. "He has even been able to start using the arm again. He can give a high five, and he lifts his arm up for me when I take his temperature."
That's something she does a lot because although Reuven's surgery is behind him, his treatment is not over. He'll be receiving chemotherapy for several more months to make sure the cancer doesn't spread back to his lungs, the most common site for metastasis of this type of cancer.
"His function is improving steadily," Boyer says. "Hopefully, he'll also do well with his chemotherapy and live a long and healthy life."