“Patients can use their legs better with the Fitbone than with an external fixator, and they complain of much less pain than when they have a frame around the leg,” says Samchukov. “And you eliminate the possibility of irritation and infection around the wires and pins of an external fixator.”

But the Fitbone, which can lengthen a long bone as much as 8.5 centimeters (3.33 inches), is only rarely applied to children because the nail, inserted in the lower leg or arm bone, would perforate the growth plate and might disturb the developing tissue near the ends of long bones. “At age 15 to 17 the growth plate is closed, and that’s when we can more easily use the Fitbone,” Thaller says.

John Birch, Samchukov’s colleague at Texas Scottish Rite, is the only orthopedic surgeon in the United States who has implanted the Fitbone. He has received special permission from the U.S. Food and Drug Administration to use the implanted distractor when external devices would increase the risk of complications. But a more widely available implantable fixator, the Intramedullary Skeletal Kinetic Distractor, or ISKD, received FDA approval in 2001. This device uses a telescoping two-part metal nail inserted in the hollow center of a femur or tibia. When the patient moves his or her knee or ankle, either through normal daily activity or during special exercises, the lower part of the rod rotates and increases in length, which distracts the bone. A handheld external sensor tracks the lengthening progress.

Besides being unsuitable for children, the implanted nails of the Fitbone and the ISKD don’t work well in bent or infected bones. “It’s difficult to get a nail down twisted, badly aligned bone,” Watson says. So he uses a Taylor Spatial Frame, an external fixator that corrects multiple deformities simultaneously using a computer-generated prescription for correcting the limb.

“Instead of all the pins and wires we used to have, newer designs let us use two rings with very few pins or wires,” Watson says. “It simplifies the process of straightening a bone.”

Yet despite recent advances in distraction, it’s currently practiced by only about 150 orthopedic surgeons in the United States. “Most orthopedic surgery is a quick fix—a total knee or hip replacement,” explains James Aronson of Arkansas Children’s Hospital. “Here you have to see the patient every week during the distraction, and of the surgeons who initially showed interest, most don’t do it because it’s so demanding in terms of time and understanding.”

Still, the technique has allowed practitioners to correct more severe deformities than had been possible. And distraction osteogenesis has spurred research that is finding ways to promote bone healing and growth in diseases that compromise bone health, such as diabetes, alcohol abuse and aging. Researchers are now experimenting with ways to generate bone more quickly so distraction osteogenesis won’t be such a long, uncomfortable procedure. What started as an accident has become a viable option for otherwise hopeless cases. And continuing advances, suggests Troulis, could have another effect. “People may opt to correct lesser deformities with this revolutionary technique,” she says.

  Dossier

1. “Basic Science and Biological Principles of Distraction Osteogenesis,” by James Aronson, in Limb Lengthening and Reconstruction Surgery, eds. S. Robert Rozbruch and Svetlana Ilizarov (New York: Informa Healthcare, 2006). In this textbook chapter, Aronson describes a variety of his discoveries, including the fact that speeding up the rate of distraction beyond two millimeters per day led to poor bone formation.  

2. “Mandibular Advancement by Distraction Osteogenesis for Tracheostomy-Dependent Children With Severe Micrognathia,” by Derek M. Steinbacher, Leonard B. Kaban and Maria J. Troulis, Journal of Oral and Maxillofacial Surgery, August 2005. Study demonstrates that distracting the jawbone with a semi-buried device can eliminate the need for an artificial airway.

3. “Craniofacial Bone Tissue Engineering,” by Derrick C. Wan, Randall P. Nacamuli and Michael T. Longaker, Dental Clinics of North America, April 2006. Reviews research into enhancing distraction osteogenesis as well as advances in cell-based tissue engineering for cases in which bone cannot be reconstructed with distraction.

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