Replacement of the Condyle and Ascending Ramus by a Modular Endoprosthesis in Macaca fascicularis— Part 1: A Clinical and Radiographic Study
Purpose
To evaluate the feasibility of replacing the condyle and ascending ramus with a novel modular endoprosthesis in Macaca fascicularis.
Materials and Methods
Eight male adult monkeys (Macaca fascicularis) were used in this study. The right condyle and ascending ramus posterior to the lower second molar were resected. An endoprosthesis consisting of 2 modules was inserted to replace the resected segment and fixed in place using polymethylmethacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The operated side of the mandible was then harvested, including the endoprosthesis and the stump of the mandible to which it was attached. Lateral mandibular radiographs were taken using standard settings immediately postoperatively and postsacrifice.
Results
Two monkeys presented with a fistula at the operated area 1 month postoperatively, but this resolved with a short course of antimicrobial treatment. At the time of sacrifice, no fistulas, dehiscences, or mobility of the endoprostheses was observed. There was no significant change in maximum mouth opening. At 3 months, a linear radiolucency was noted at the cement-bone interface in the 2 monkeys that previously presented with fistulas; whereas at 6 months, none of the 4 animals showed any radiolucency.
Conclusions
The use of a cemented modular endoprosthesis for replacement of the condyle and ramus unit was feasible with minimal complications allowing normal mouth opening and occlusion. Further histologic and microfocus computed tomographic studies will be done to confirm the findings.
⁎Senior Consultant, Department of Oral and Maxillofacial Surgery, National Dental Centre, Republic of Singapore
†Registrar, Department of Oral and Maxillofacial Surgery, National Dental Centre, Republic of Singapore
‡Emeritus Professor, University of Hong Kong, Hong Kong; Research Advisor and Visiting Consultant, National Dental Centre, Singapore; Professor, Prince of Songkhla University, Hat Yai, Thailand; Advisor, Tideman Maxillofacial Centre, Hong Kong, Republic of China
§Emeritus Professor, Radboud University, Nijmegen, and University of Maastricht, The Netherlands
Address correspondence and reprint requests to Dr Goh: Department of Oral and Maxillofacial Surgery, National Dental Centre, 5 Second Hospital Avenue, Singapore, 168938, Republic of Singapore
Funding agencies: National Medical Research Council (NMRC)/National Dental Centre (NDC)NMRC/EG/NDC/2005/2006/Supplementary(1) and (2). Singhealth Foundation Grant: SHF/ SP001/2007.
ABSTRACT