Distraction Histiogenesis: Principles and Indications.

Distraction histiogenesis is a biologic phenomenon that can be utilized to induce the formation of new bone and soft tissue. This technique has been used after corticotomy or osteotomy of bone to treat patients with limb-length inequality, angular deformities, segmental bone loss, nonunions, and contractures. A distraction force is applied with an external fixator, such as the Ilizarov circular fixator or a uniplanar fixator. The authors review the extensive preoperative planning required, the performance of osteotomy, the application of external fixators, and the timing between the osteotomy and the initiation of correction (the latency phase). The subsequent distraction phase involves active lengthening, transport, or angular correction through frequent small steps (e.g., 0.25 mm every 6 hours). This results in the formation of new bone, or regenerate, in longitudinal columns along the plane of distraction. The consolidation phase begins after the desired correction has been achieved; this period allows for maturation of the regenerate and corticalization before fixator removal.