Initial Experience With rhBMP-2 Delivered in a Compressive Resistant Matrix for Mandibular Reconstruction in 5 Dogs

ObjectiveTo document cumulative initial experience and long-term follow-up of the use of rhBMP-2/CRM for reconstruction of large mandibular defects (5cm) in dogs. Study DesignRetrospective case series. AnimalsDogs (n=5). MethodsMedical records (October 1999-April 2011) of dogs that had mandibular reconstruction for defects/resections of 5cm using rhBMP-2/CRM were reviewed. Signalment, preoperative assessment/rationale for mandibular reconstruction, surgical methods, postoperative assessment of the reconstruction (evaluation of occlusion), and complications were recorded. A definitive histologic diagnosis was obtained in dogs that had mandibular resection for mass removal. Long-term complications were determined. A minimum time frame of 2-year in-hospital follow-up was required for case inclusion. ResultsMandibular reconstruction was successfully performed in all dogs' defects where gaps of 5-9cm were bridged. Surgical reconstruction rapidly restored cosmetic appearance and function. All dogs healed with new bone formation across the gap. New bone formation was present within the defects as early as 2 weeks after surgery based on palpation, and new bone formation bridging the gap was documented radiographically by 16 weeks. Minor complications occurred in all dogs in the early postoperative period, and included early firm swelling and gingival dehiscence in 1 dog; late plate exposure in 3 dogs; and exuberant/cystic bone formation in 2 dogs (related to concentration/formulation of rhBMP-2/CRM). Two dogs had minor long-term complications of late plate exposure and a non-vital canine tooth; the plates and the affected canine tooth were removed. Long-term in-hospital follow-up was 5.3 years (range, 2-12.5 years); further long-term telephone follow-up was 6.3 years (range, 2-12.5 years). All owners were pleased with the outcome and would repeat the surgery again under similar circumstances. ConclusionThe efficacy and success of this mandibular reconstruction technique, using rhBMP-2/CRM with plate fixation, was demonstrated with bridging of large mandibular defects regardless of the underlying cause, and with excellent cosmetic and functional results. Complications were common, but considered minor and easily treated. The complications encountered revealed the importance of tailoring the use of BMPs and fixation methods to this specific anatomic location and indication.