IADR Abstract Archives
Design & Evaluation of A Novel Titanium Modular Endoprosthesis for the Repair of Segmental Mandible Defects in Macaca Fascicularis
Objectives: Current gold standard for mandible reconstruction using the fibula free flap is associated with disadvantages such as donor site morbidity, long hospitalization stay and rehabilitation. Our aim is to design and evaluate a titanium modular mandible endoprosthesis to provide stable reconstruction of a segmental mandible defect. Using a preclinical Macaca fascicularis mandible model, the load-bearing capability of the endoprosthesis will be evaluated using a finite element (FE) model prior to in vivo implantation.
Methods: To design the dimensions of the endoprosthesis, mandibles from euthanized Macaca fascicularis were harvested and measured using a vernier caliper. Functional performance of the implanted endoprosthesis within the mandible defect was simulated under an average bite force of 100N. The endoprosthesis was implanted within the resected right mandibular body of Macaca fascicularis (n=10) and monitored over 4 months. Radiological imaging of the entire mandible and bone volume analysis around endoprosthesis stems using micro-CT analysis were performed.
Results: Computational simulations showed a maximum relative movement of 20um at the interface of the implanted endoprosthesis stem within the mandibular stump, predicted to be favorable for osseointegration to occur. At 4-months harvest, preclinical investigations showed no swelling, infection or endoprosthesis failure (n=10). No dehiscence was noted in n=4, whereas n=6 showed dehiscence at the superior aspect of either the body module, anterior stem module or posterior stem module. Five were stable throughout at the site of implantation, whereas n=5 showed initial stability in the first 4 weeks with slight mobility at the anterior bone by Week 12 due to screw loosening. On average, the endoprosthesis study group showed 88.8±10.7% bone volume around the endoprosthesis stems compared to non-operated mandible control group.
Conclusions: Preclinical investigations using the modular mandible endoprosthesis (PCT/SG2017/050139) showed promise as an alternative strategy to segmental mandible reconstruction. The extent of bone-implant contact will be further verified using histological analysis.
Methods: To design the dimensions of the endoprosthesis, mandibles from euthanized Macaca fascicularis were harvested and measured using a vernier caliper. Functional performance of the implanted endoprosthesis within the mandible defect was simulated under an average bite force of 100N. The endoprosthesis was implanted within the resected right mandibular body of Macaca fascicularis (n=10) and monitored over 4 months. Radiological imaging of the entire mandible and bone volume analysis around endoprosthesis stems using micro-CT analysis were performed.
Results: Computational simulations showed a maximum relative movement of 20um at the interface of the implanted endoprosthesis stem within the mandibular stump, predicted to be favorable for osseointegration to occur. At 4-months harvest, preclinical investigations showed no swelling, infection or endoprosthesis failure (n=10). No dehiscence was noted in n=4, whereas n=6 showed dehiscence at the superior aspect of either the body module, anterior stem module or posterior stem module. Five were stable throughout at the site of implantation, whereas n=5 showed initial stability in the first 4 weeks with slight mobility at the anterior bone by Week 12 due to screw loosening. On average, the endoprosthesis study group showed 88.8±10.7% bone volume around the endoprosthesis stems compared to non-operated mandible control group.
Conclusions: Preclinical investigations using the modular mandible endoprosthesis (PCT/SG2017/050139) showed promise as an alternative strategy to segmental mandible reconstruction. The extent of bone-implant contact will be further verified using histological analysis.