Correction of mandibular nonunion and malocclusion by plate fixation and autogenous cortical bone grafts in two dogs.

Abstract

Two dogs were treated for severe malocclusion secondary to segmental defects in the mandibular bodies as a result of nonhealing mandibular fractures. The problems of fibrous nonunions with large fracture gaps, the potential for infection, and the severe malocclusion were addressed in considering definitive surgical correction. The segmental defects in both dogs were spanned by use of autogenous cortical grafts (full-thickness rib segments or full cortical diaphyseal ulnar segments), supplemented with autogenous cancellous graft, and were stabilized with screw-and-plate fixation. Radiographic evaluation of bone healing and graft incorporation was difficult because of the implants, which obscured full observation of the bone graft sites. Successful graft revascularization, determined by 99mradiophosphate localization, was shown in both dogs; fairly uniform isotope uptake was observed throughout the graft sites and was continuous with the recipient bone. Mildly increased uptake was observed at 6 months and at 1 year after surgery and was considered consistent with remodeling associated with fracture healing. Observation of complete graft revascularization within 1 year provided ample evidence that the autografts were incorporated, with sufficient remodeling to characterize bone union.