Modeling Micro-Scaffold-Based Implants for Bone Tissue Engineering

摘要

Metabolic bone diseases are at the forefront of scientific and biomedical research worldwide. Diseases such as osteoporosis are characterized by increased bone fragility, which leads to micro-architectural deterioration of bone tissue and eventually to micro fractures. At the micro-structural level, bone is constructed from thin rods known as trabeculae and plates. These rods and plates are arranged in semi-regular, three-dimensional patterns and constitute highly anisotropic and heterogenic material. The bone micro-structure is stochastic in nature and varies according to patient, bone type and location within a specific bone. Diagnostic abilities rely on high technology and advanced methods for 3D micro scanning, modeling and analyzing the bone micro-structure. We propose a novel method for modeling scaffold-based implants that have the stochastic structure of bone and can be customized according to given bone structures. The method for designing these implants is based on a 3D pattern synthesis technique that can be applied to the diseased cavities of a given bone. The implants will replace these cavities in the cancellous bone. Recognizing these cavities is a difficult process, since such bone is characterized by a complex micro-structure composed of thin cylindrical rods and plates. Cavities with this 3D micro-structure will be identified by measuring the volumes of those cavities and comparing them to a specified threshold. The in-filling will be based on a 3D pattern growing scheme that takes the exerted forces into account so that the global directionality of the micro-structure is preserved. Furthermore, the goal is to optimize the topology according to mechanical rules. Due to the complexity of the problem, the approach is initially examined only for 2D medical images. The main contribution of this method is that the structure of the micro-implants will not be the current standard structure (cubes with holes), which lack the characteristics of a given bone structure. Moreover, this method can be used to design and manufacture customized micro-implants according to the specific stochastic micro-structure of a given bone. These customized designed implants can be manufactured using micro-RP technology.