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A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible
Published on: January 28, 2020
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Third-generation modular mandible endoprosthesis in Macaca fascicularis
Y Liu1, R Lim2, N Chanchareonsook3
1National Dental Research Institute Singapore, National Dental Centre Singapore, Singapore; Oral Health Academic Clinical Programme, Duke-NUS Medical School, Singapore.
International Journal of Oral and Maxillofacial Surgery
|December 4, 2020
Summary
A new modular mandible endoprosthesis design with incorporated movement reduces stress, enhancing bone integration. This improved stability in animal models suggests potential for better long-term outcomes in reconstructive surgery.
Area of Science:
- Biomaterials Engineering
- Oral and Maxillofacial Surgery
- Orthopedic Implant Design
Background:
- Mandible reconstruction often requires endoprostheses, but stress concentration at implant stems can lead to micromotion and instability.
- Previous generations of modular mandible endoprostheses have faced challenges with long-term osseointegration due to stress-related issues.
- Developing a third-generation endoprosthesis aims to overcome these limitations by minimizing stress and promoting biological fixation.
Purpose of the Study:
- To develop and evaluate a third-generation modular mandible endoprosthesis designed to reduce stress concentration at the implant stems.
- To investigate the hypothesis that incorporating controlled movement between modular interfaces enhances osseointegration and long-term stability.
- To compare the performance of a modular endoprosthesis with integrated movement against a rigid design in a preclinical model.
Main Methods:
- A three-piece modular mandible endoprosthesis system was designed with varying degrees of movement at module interfaces.
- The endoprosthesis was fabricated from commercially pure grade 4 titanium, with specific machining and surface treatments.
- The system was implanted in segmental mandible defects in nine Macaca fascicularis, followed by clinical, radiological, histological, and histomorphometric assessments at 4 months.
Main Results:
- Endoprostheses incorporating movement demonstrated significantly superior performance compared to the rigid system.
- A 30.9-34.8 times higher percentage of bone-implant contact and a 3.4-4.1 times greater bone area were observed (P<0.0001).
- Osseointegration was evident at the posterior stems, though fibrous encapsulation occurred around anterior stems in all groups.
Conclusions:
- The degree of movement incorporated into the modular mandible endoprosthesis favorably impacted bone healing and implant stability.
- The findings support the potential of this design to improve osseointegration in mandible reconstruction.
- Further research is needed to optimize strategies for reducing stem loading and ensuring predictable osseointegration throughout the implant.
