Stability as a Key Factor for Bone Repair in Nonunion of Mandibular Osteotomy

Abstract

Stability is necessary to ensuring proper bone repair after osteotomies and fractures. The aim of this research was to analyze how the repair of pseudoarthrosis sites was affected by different conditions in related to soft tissue. An experimental study was designed with 18 New Zealand rabbits. Six study groups were formed. An osteotomy was performed on the mandibular body of each animal and muscle was installed at the osteotomy site to model pseudoarthrosis. Fixation by surgery was then carried out, using plates and screws. The animals were submitted to euthanasia after 21, 42 and 63 days to make a descriptive comparison of the histological results. No animal was lost during the experiment. In all the samples, bone formation was observed with different degrees of progress. Defects treated with or without removal of the tissue involved in pseudoarthrosis presented comparable bone repair, showing that stability of the bone segments allows the repair of adjacent tissue. In some samples cartilaginous tissue was associated with greater bone formation. Stabilization of the fracture is the key in bone repair; repair occurs whether or not the pseudoarthrosis tissue is removed.