33rd Annual Scientific Meeting proceedings

This report describes the first patient-specific implant (PSI) that has been placed for a critical sized defect in mandibular reconstruction of a dog with an acantomatous ameloblastoma. The aim is to achieve oral stability and ideally verify osteosynthesis to bridge the mandibular bone defect created after tumour surgical excision.

A seven-year-old neutered cross-breed dog was presented with a focal 60x45mm mildly ulcerated, mass to the left mid mandible. Histopathology confirmed the diagnosis. Computed tomography (CT) was utilised to evaluate the extent of the lesion and exclude regional and distant metastatic disease. The surgery was planned in two stages: a segmental unilateral mid-body left mandibulectomy followed by the placement of a PSI to bridge the 85mm bone defect. The implant was designed with a channel to be filled with a non-compressible bone grafting sponge material, which was infused with a solution containing recombinant human bone morphogenetic protein-2 (rhBMP-2). A follow up CT was performed on the day of the surgery and six months post-operatively.

Filling the porous titanium scaffold with a master-graft bone strip mixed with rhBMP-2, stimulated partial osseous integration of the implant, however there was no evidence of complete osteosynthesis bridging the defect as initially expected.

This study reflects a recent surgical therapeutic approach that can be useful to stabilise mandibles, following mass resection. The use of PSI improves patient welfare by stabilising the mandibles and temporomandibular joints, allowing physiological mechanisms that are considered essential for oral function and preventing the pain associated with mandibulectomy complications.