One of Nature's Best Kept Secrets

NEARLY 50 years ago, in a small industrial town in the western part of Siberia, something really exciting happened in the history of medicine. A physician named Gavril Ilizarov performed an osteotomy in a patient to correct a severe deformity of the lower limb. He knew that if he were to break the bone and then straighten the leg in one maneuver he would run the risk of stretching nerves and blood vessels and potentially do more harm than good. His strategy, therefore, was to use percutaneous wires to transfix the bone proximal and distal to the osteotomy site, connect the wires to an external circular frame, and then gradually distract the ends of the bone at a rate of about 1 mm per day. He assumed that this treatment would create a large gap at the osteotomy site which would require a subsequent bone graft procedure. When he attempted to perform the bone graft operation, however, he was stunned by the finding that the gap was completely filled with new bone! At that point in history the discovery of a method for regenerating bone in humans had been made. Ilizarov devoted his life to the research, development, and refinement of this minimally invasive procedure which would allow entire sections of the skeleton to be lost or resected and then filled in with abundant amounts of new bone. His clinical successes in the salvage of limbs which would otherwise have been amputated, and in the return of disabled patients to productive levels of activity, eventually spread by word of mouth throughout the communist block of countries. Unfortunately, news of this discovery did not travel beyond the Iron Curtain until 1981. At that time, an Italian explorer who had been injured in a mountain climbing accident in Siberia was transferred to Ilizarov’s hospital for treatment. He then returned to Italy to report of his experience. Shortly thereafter, a group of Italian surgeons made a pilgrimage to visit Ilizarov to learn of this technique. Within a few years the method became adopted worldwide as the primary procedure for lengthening limbs, correcting deformities, and treating nonunions of bone secondary to trauma, infection, or tumor. One of the most profoundly interesting aspects of this biological phenomenon is that it seems to contradict some of the basic assumptions made about the formation of bone and the way by which mechanical forces affect osteogenesis. Most students of biology and biomechanics believe that compression, weight-bearing, and stress-generated potentials in bone lead to osteogenesis. On the contrary, distraction has never been thought to be a stimulus for osteogenesis and in fact, most orthopedic surgeons consider a fracture that is subjected to such forces to be at risk for becoming a nonunion. What no one understood is that if these forces could be applied to a healing bone in such a way that the rate and rhythm of distraction could be controlled, the human body has the capacity to make virtually unlimited amounts of new bone as long as the soft tissues in the limb can accommodate the lengthening. To appreciate the contributions of Ilizarov, it is necessary to recognize the historical events which preceded his achievements. Bone lengthening and the use of external fixation had both been reported earlier and, in fact, the first report of a successful lengthening of a limb was made by Codivilla in 1905. Yet it was Ilizarov who used his creative mind to take full advantage of this phenomenon and apply the new-found procedure to treat a spectrum of skeletal conditions. Among some of the most illustrative examples is the lengthening of amputation stumps to provide a weight-bearing foot (Fig. 1), the transport of bone to heal a segmental traumatic defect (Fig. 2), and the lengthening of limbs in patients with achondroplastic dwarfism (Fig. 3). As one might have expected, orthopedic investigators from around the globe gravitated to this new field of study and began exploring ways of optimizing the method for clinical purposes. Different rates and rhythms of distraction were tried; one company in Alaska concocted a motor-drive apparatus for providing continuous distraction, and clinicians began reporting on their experiences. Unfortunately, the technique is associated with several problems and complications including pin tract infection, skin irritation, severe pain (presumably associated with the concomitant