Experimental Implant Grows With Young Limbs; Technology Spares Bone Cancer Patients Painful Surgeries There is a new type of implant: an experimental model called Repiphysis, designed like a spring-loaded curtain rod, which can be lengthened without surgery. Instead of operating, doctors expand the implant by creating an electromagnetic field around it. That softens plastic inside the prosthesis, allowing an internal spring to unwind slightly. Doctors allow the spring to stretch only a few millimeters at a time to avoid damaging surrounding nerves and tissue. The field is removed after a few seconds, allowing the plastic to cool and harden instantly. Children with a lot of room to grow, such as toddlers and preschoolers, may be too small to benefit from Repiphysis, says J. Sybil Biermann, an orthopedic surgeon at the University of Michigan Cancer Center. Older teens may opt for a permanent, non-expandable prosthesis. She says the device could help up to 100 of the 415 American children a year who are diagnosed with bone cancer. More than 130 devices have been implanted around the world, says a spokeswoman for its manufacturer, Tennessee-based Wright Medical Technology Inc. Experts say the implant, though groundbreaking, is too new for doctors to know whether it will be reliable in the long term or solid enough to change the standard of care. With traditional implants, orthopedic surgeon Mike Neel says, children often have to choose between the pain of more frequent surgeries or the discomfort of mismatched limbs, which can risk nerve damage. "This allows us to grow the leg more like it needs to be grown," Neel says. "The old way, he'd always be catching up or ahead. They'd get a growth spurt, so you'd do this big surgery. But because you can only lengthen it two centimeters at a time, they'd still come up short." Doctors note that Repiphysis, which was approved by the Food and Drug Administration in December 2002 to replace sections of the thigh and upper shin bone, has limitations. Like other prostheses, it carries some risk of infection and may loosen, break or wear out over time, says Thomas Shives, a professor of orthopedic surgery at the Mayo Graduate School of Medicine. And in a study of 15 patients, published last year in the journal Clinical Orthopaedics and Related Research, Neel and his colleagues noted that surgeons had to operate again on seven patients because the prostheses fractured or loosened. One patient had a leg amputated after she developed an arterial blood clot. Most children said the lengthening procedures were about as uncomfortable as physical therapy, according to the article. Some took mild pain relievers. Two needed general anesthesia because of "emotional problems and an inability to cooperate while awake" during the study, which took place from 1998 to 2001. Three decades ago, more than 70% of children with bone cancer died, Shives said. Now, more than 70% live. Yet experts noted that children who survive cancer still face a number of risks. Chemotherapy can damage the heart; radiation can cause second cancers. "I don't want people to think that patients will have no other problems," Biermann says. "It's an improvement, but it's still a difficult situation. We still don't have the technology to give them the limb they had before." Thanks to USA Today, 7/04 LINK to company that manufacturers these devices Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.