Immediate Mandibular Reconstruction of a 5 cm Defect Using rhBMP-2 After Partial Mandibulectomy in a Dog

Objective— To report treatment of a complex odontoma of the mandible by partial mandibulectomy and immediate surgical reconstruction using bridging plate fixation with a synthetic graft. Study Design— Clinical case report. Animals— A 4-year-old male castrated cocker spaniel. Methods— Immediate reconstruction of the left mandible (5 cm gap) was performed after complete excision of a complex odontoma. Locking plate fixation was applied immediately before complete excision of the mass. Fixation was removed, then after partial mandibulectomy, including all abnormal tissue, restored to achieve occlusion. The resulting mandibular defect was filled with recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered in an absorbable collagen sponge containing hydroxyapatite/tricalcium phosphate granules (compression resistant matrix [CRM]). Results— New bone growth was evident radiographically and on palpation at 3 months. Bony remodeling was evident during follow-up examinations up to 26 months. Bone collected by biopsy at the graft site at 7 months had robust new bone formation and evidence of continued remodeling. Only minor complications (repeated intraoral plate exposure) were encountered postoperatively and were easily resolved. Conclusions— An osteoinductive factor (rhBMP-2/CRM) was successfully used as a graft substitute in immediate reconstruction of a large mandibular defect. Clinical Relevance— Immediate reconstruction of large mandibular defects with osteoinductive materials as a graft substitute may be a viable alternative to partial mandibular resection or radiation therapy for benign odontogenic tumors in dogs.