Bridging bone gaps with the Ilizarov technique. Biologic principles.

For the treatment of bone gaps of less than 4 cm, cancellous autografting remains the treatment of choice. But for gaps exceeding 4 cm, the distraction osteogenesis is a viable option. The following conditions should be satisfied: (1) patient selection; (2) stable fixation; (3) osteotomy by corticotomy; (4) 7- to 14-day latency period before initiating distraction; and (5) a controlled rate and rhythm of distraction of 1 mm per day (0.25 mm, four times a day). This type of treatment leaves the pathologic focus alone, and bone healing occurs on the healthy bone. The quality of bone regenerate may be improved by a motorized unit and by better soft-tissue coverage using early grafts and flaps. Interface healing is probably improved by cancellous grafting and internal fixation after the transport period, thus decreasing the fixator time.