September 1, 2005 A new kind of expandable bone prosthesis -- implanted in the legs of pediatric patients to substitute bone that was removed due to cancer -- is helping children avoid amputations and lead a normal life. The procedure could some day help trauma patients as well.
DALLAS--Not long ago, bone cancer often meant amputation. Now researchers have found a little pressure can go a long way in saving a leg. A new treatment can help keep parts of the limb while allowing it to grow.
Novie Helsel keeps a close eye on her 10-tear-old son Russell, who has bone cancer. "It's hard for you to see your child go through all of that and have to be so sick going through everything," she says. "I asked her what a tumor is, and she said cancer. So I started crying, too," Russell says.
Al Mollabashy, an orthopedic oncologist with the Orthopedic Associates of Dallas says, "You can actually see where the cancer has grown into the muscles and soft tissues of the thigh." After he removed the tumor, Mollabashy thought Russell would benefit from a new kind of bone implant.
The implant, called the Compress, combines pressure with an expandable prosthesis. Dr. Mollabashy says, "He's 10, so he needs a durable construct that'll last more than 10 to 20 years. It needs to last decades if he survives this disease."
Compress' constant force helps maintain bone strength and density. Russell describes a part of his leg, "Right here is part of a metal kneecap. I still got this part of it." After he finishes chemotherapy, doctors can expand the prosthesis regularly so Russell's legs will grow at the same rate.
Novie says, "He's bounced back so quickly, that it has just amazed me." Four months after surgery, Russell is already making a splash in the pool with his reconstructed leg. Although his condition is rare, Dr. Mollabashy believes this kind of implant might someday be used in other joint replacement and trauma surgeries.
BACKGROUND: An expandable metal bone is implanted in the legs of young cancer patients so that the prosthetic bone grows with the child.
HOW IT WORKS: An orthopedic oncologist is implanting an expandable bone prosthesis in a seven-year-old cancer patient who will have part of his bone removed after treatment. In the past ten years, doctors have used ultrasound and expanding plastics to lengthen bone prostheses, but the bone cement (similar to the kind used for denture work) needed to attach the prosthesis has created irreversible damage. This is a new combination procedure that, instead of bone cement, uses a spring mechanism and allows the surgeon to adjust the length of the bone by inserting a telescope guided pin through a small incision in the leg as the child growths.
CHILDHOOD CANCERS: The most common form of cancer in children is childhood acute lymphocytic leukemia, or ALL. Lymphocytes, a type of cell that helps fight infection, develops in bone marrow. If the lymphocytes grow too quickly and do not fully mature, the child has ALL. It can cause anemia, easy bruising or bleeding and swollen lymph nodes. Doctors use a blood test to count the numbers of different types of blood cells – too many white blood cells can indicate leukemia.
A RARE DISEASE: In the United States in 2005, approximately 9,510 children under age 15 will be diagnosed with cancer. But cancer is still relatively rare in this age group with, on average, 1 to 2 children developing the disease each year for every 10,000 children in the United States.
ON THE WEB:
- International Society of Limb Salvage
- Musculoskeletal Tumor Society and additional links
- More about Biomet's bone salvage products
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.