Research and develop innovative procedures in state of the art computer-experimental evaluation systems on the mechanical behavior of implants for orthopedic and vascular surgery.

The rapid dynamics of innovation in the medical-hospital sector and consequent high offer of distinct technologies for health brings up the demand for scientific research and technologies research that allow the determination of safety and effectiveness of its products and surgical techniques employed in orthopedic and vascular surgery. At present, in the Orthopedic Biomechanics and Vascular Biomechanics fields, these applied researches rely on physical characterization of implantable medical devices and biomechanical systems formed by the interaction of these implants with the bone structure. In addition, the ability to build a model and computer-simulate these biomechanical system´s behavior allow for improvements to be investigated as well as the obtaining of objective data that make possible the selection of a superior surgical technique in comparison to other.

Activities

1. Development and improvement of spine representative computer model with progressive insertion of improvements in the representation of soft tissues and connective system. Use the virtual model of the spine to simulate and evaluate the biomechanical performance of different surgical treatments employing spine implants such as stabilization of pedicle and intervertebral spacers systems, aiming to identify advantages of treatments, safety and effectiveness of the used implants. Improvement of systems and experimental devices to perform standard mechanical tests (ASTM / ISO) and non-standard procedures in systems and orthopedic components of the spine which provide subsidies and parameters for the simulation models

2. Development and improvement of a human knee representative computational model with progressive insertion of enhancements on the representation of soft tissues and correspondent connective system. Utilization of a virtual knee model to simulate and evaluate the biomechanical performance of different knee joint surgical treatments (total knee arthroplasty) and stabilizing structures (ligamentoplasty) aiming to identify advantages between treatments and safety/effectiveness aspects of implants and prostheses, as well as investigate the failure mechanisms registered in clinical use of these medical devices. Improvement of systems and experimental devices to perform standard mechanical tests (ASTM / ISO) and non-standard procedures in systems and orthopedic components of the knee which provide subsidies and parameters for the simulation models

3. Development of computational models to evaluate/estimate characteristics of the mechanical performance of stents and/or metallic stent-grafts (radial force, elastic return). Development of models for self-expandable and/or expandable through balloon during the insertion (navigability) and use (pulsatile fatigue). Experimental analysis of device´s behavior on standard tests (ASTM-ISO) of insertion and use (fatigue 380 x 106cycles) of these vascular devices, consequently providing information for the computer models.

4. Study and development of phenomenological variational models to simulate the behavior of biological tissues (connective and vascular tissues) which allow the calibration originated by homogenization processes (multi-scale, item 5.1.1) and/or experimental. Improvement of techniques and execution of assays in vitro for study. Characterization of biological tissues (connective and vascular) using optical methods and multi-axial test devices for the evaluation of anisotropic properties and identification of parameters in material models.

Goals

1. By the end of 2017: Improvement of the available spine model and evaluation of the mechanical response in different devices, spine fixation techniques (arthrodesis) and intervertebral disc prostheses with their comparative analyzes of clinical impact.
2. By the end of 2017: Execution of experiments and simulation of expansion of stents with comparative performance evaluation estimating ease of implant, behavior during loading cycles, radial force values, elastic return and pulsatile fatigue resistance.
3. By the end of 2019: Development of a knee model that allow comparative mechanical performance simulation of prostheses and implants. Performance analysis linked to the execution of experimental tests on the same implants allowing mechanical evaluation with clinical impact on products/systems.
4. Up to 2021: Development of appropriate constitutive models for biological tissues and incorporation of these models in systems simulation (spine / knee joint) in implant´s biomechanical valuation analysis.

Impact

The use of prostheses and implants in orthopedics and vascular surgery has enabled significant improvements on the quality of life of patients whose functional abilities were compromised by traumatic processes or diseases on musculoskeletal system and/or circulatory. Tough there has been expressive advances on the development of new materials and undeniable progress on techniques for placement and design of surgical implants, the occurrence of failures and complications during the use of these medical devices is still frequent. These failures have been attributed to different mechanisms of mechanical origin (overload, wear, fatigue), physic/electrochemical (corrosion, degradation) or associated with inappropriate use of the implant, inappropriate surgical procedure, low quality project and fabrication, wrong selection of material, between others.

Failures and adverse events encumber the public health system and the society in general, through the hospitalization time due to revision surgeries, implant´s cost, and patient time away from work. The consolidation of the scientific and technological domain of surgical implants contributes positively to this panorama.