Mandibular reconstruction of a partial hemimandibulectomy in a dog with severe malocclusion

OBJECTIVE: To report treatment of severe mandibular malocclusion (after left partial hemimandibulectomy, approximately 7 cm gap). STUDY DESIGN: Clinical report. ANIMALS: A 14-month-old golden retriever. METHODS: After corrective osteotomy of the right horizontal mandibular ramus, normal occlusion was reestablished and temporarily maintained while both mandibles were stabilized by miniplates on the lateral alveolar surface spanning the bilateral mandibular defects (right=1.5 cm, left=7 cm). A fenestrated, monocortical rib graft was positioned beneath the left gingival surface to protect the synthetic graft, which was secured to the miniplate. A mandibular reconstruction plate (right) and a locking mandibular reconstruction plate (left) were secured to the ventral borders of the mandibles. Recombinant bone morphogenetic protein-2 delivered in collagen tricalcium phosphate sponges (rhBMP-2 collagen-TCP sponge) was inserted into both mandibular defects. RESULTS: New bone formation was identified at 3 months and bony remodeling was evident at recheck examinations up to 4 years. Scintigraphy (6 months, 1 year) confirmed graft revascularization and viability. Bone collected (1 year) from the left defect site had robust new bone formation and evidence of continued remodeling. Only minor complications were encountered during the postoperative period and were easily resolved. CONCLUSIONS: Reconstruction of a large mandibular defect was facilitated by use of an osteoinductive factor (rhBMP-2 collagen-TCP sponge) as a graft substitute. CLINICAL RELEVANCE: One-step salvage and reconstruction facilitated by use of an osteoinductive factor, as a graft substitute, may be an alternative strategy for repair of large mandibular defects.