Distraction osteogenesis
remains one of the most mysterious phenomena of bone biology. During distraction
osteogenesis, new bone forms under the mechanical conditions of gradual intermittent
traction superimposed on attenuated functional loads. The nature of this mechanical
environment and the dynamics of the forming regenerate bone are not typical of that found
elsewhere in the skeleton (Waanders et al., 1992).
The successful application of the
distraction osteogenesis technique is equally dependent on biological and biomechanical
factors. The basic biological factors include a lower-power
osteotomy with maximum preservation of osteogenic tissues including the periosteal and
endosteal blood supply, an adequate duration of the latency period to allow development of
the fracture callus, an optimal rate and rhythm of distraction, and a sufficient time for
remodeling of the newly formed bone prior to unrestrained functional loading. The biomechanical
parameters of distraction can be divided into several categories: extrinsic
or fixator-related factors, intrinsic or tissue-related factors, orientation of the
distraction vector, and device orientation.
