Surgical induction of temporomandibular joint ankylosis: An animal model

Purpose: The aim of this study was to develop an animal model of temporomandibular joint (TMJ) bony ankylosis for future evaluation of surgical reconstructive methods. Materials and Methods: An animal model was selected on the basis of 2 sequential experiments. Four goats and 4 minipigs were used in the first experiment, in which I goat and I minipig served as control animals. Condylectomy with disc preservation was performed on I side of 3 animals in each group. On the contralateral TMJ, condylectomy with discectomy was performed, and the arthroplasty gap was filled with the autogenous bone chips. In the second experiment, TMJ ankylosis was induced bilaterally in 3 additional animals of the species that achieved better ankylosis results in the first experiment. All animals were killed postoperatively at 3 months, and the TMJ complexes were examined by plain radiography, computed tomography, and histological evaluation. Results: in the first experiment, only fibrous ankylosis; was observed in the bone-grafted side of 2 goats and 3 minipigs, whereas fibro-osseous ankylosis was achieved in the remaining goat. The extent of ankylosis was found to be more severe in the goats than the minipigs. Hence, goats were selected for bilateral surgery in the second experiment, which achieved consistent bony ankylosis of the TMJ in all animals. Conclusions: Goats provide a better TMJ bony ankylosis model than minipigs. Consistent bony ankylosis can be induced by bilateral condylectomy, disectomy, and bone grafting of the arthroplasty gap. (c) 2007 American Association of Oral and Maxillofacial Surgeons