Topology Optimization of Bionic Porous Structure Based on Biomechanical Properties of Trabecular Bone / 医用生物力学

Objective Based on structure of animal trabecular bone, implants with porous structure were designed to describe mechanical properties of trabecular structure and explain significance of bionic trabecular porous implants in clinical treatment. Methods Based on anisotropic mechanical properties of animal trabecular bone, a porous structure was designed using the topology optimization method. The principles of partition and block reconstruction were first proposed according to bone function theory. The trabecular structure was then reconstructed based on micro-CT images. The boundary constraint and external load were applied on this model according to the respective-volume-element (RVE) method. Taking the solved mechanical properties as objective functions of optimization, the porous structure design and optimization were conducted using the variable density method and the homogenization method. Results The trabecular bone possessed the anisotropic mechanical properties. It was found that the volume fraction showed an increasing trend from the edge to the middle across the same section of trabecular bone. But there was no obvious regular pattern in Poisson’s ratio, which was evenly distributed in the range between 0.17 and 0.30. As to the values of elastic modulus and shear modulus, they were both significantly higher in the main pressure position compared with those in the other positions. After topography optimization based on these mechanical properties, the Poisson’s ratio of the optimized model was in the same range as the animal trabecular bone. The elastic modulus error was less than 14%， with the minimum being only 3%. In addition, the shear modulus error was below 8%， which ultimately complied with criteria of the original goal. Conclusions The designed porous structure based on topology optimization had the same anisotropic characteristics as animal trabecular bone, while reducing the stress concentration phenomenon, which could achieve the specific design for porous structure, thus providing a reasonable and effective method for clinical porous implants.

Integrated TCM and Western Treatment Development of Anterior Ischemic Optic Neuropathy / 中国中医药信息杂志

Anterior ischemic optic neuropathy (AION) is the ciliary artery-circulatory disorders for the supply of optic nerve head area before the sieve plate prozone and sieve plate district, result in the insufficient blood supply of the optic nerve head and ischemia hypoxia, edema. Clinical manifestations of the type with non-artery inflammatory neuropathy and artery inflammatory neuropathy, which would both eventually lead to the irreversible damage to the optic nerve. In the early phase of AION, the main method is giving a glucocorticoids intravenous drip and a periglomerular injection (or retrobulbar injection) in time, but using the glucocorticoids for a long time or in quantity can cause a series of complications. Therefore, the combination of traditional Chinese and western medicine treatment of AION has become more and more significant in clinic.