Digital Design And Additive Manufacturing Of Skull Repair Medical Protective Cover

Skull repair surgery has always attracted the attention of patients and medical staff because of its long cycle,high risk,and difficult nursing.The continuous application and development of additive manufacturing technology and computer-aided technology in the medical field provide a new research approach and method for skull repair surgery.Relevant research results have been applied to virtual plastic surgery,archaeology,and criminal investigation.After decompressive craniectomy for patients with skull defects,the repair site is only wrapped by a layer of the scalp,and multiple drainage operations are required during the period.The repair site is easily affected by internal and external factors such as secondary injury.It is urgent to design an external skull protection device to assist the medical treatment process.Given the clinical practice of patients with skull defects before repair surgery,the biodegradable material polylactic acid was used as the research object.Computer medical imaging technology,reverse engineering technology,finite element analysis technology,and additive manufacturing technology were used to design and study the skull protective cover,and the structure and molding process parameters of the protective cover were optimized.The main research contents are as follows:(1)The spiral CT equipment was used to scan the brain patients,and 151 two-dimensional CT images were selected.The three-dimensional digital model of skull defect was constructed by image segmentation,region growth,three-dimensional interpolation,and denoising.According to the contour parameters of the surface of the repair site,the direct fitting method and the mirror repair method were used to construct the surface of the skull prosthesis.(2)To meet the requirements of the feasibility,mechanical performance reliability,environmental protection,and low cost of the protective cover structure,based on the surface modeling theory and medical image data processing,two polylactic acid material protective covers suitable for patients were designed.By changing the surface structure of the protective cover,thermal-mechanical analysis,and collision dynamics simulation analysis,the mechanical properties of the two protective covers are compared.(3)Orthogonal test method and weighted comprehensive evaluation method were used to optimize the forming process parameters of tensile properties and bending properties of the protective cover(printing layer thickness,shell wall thickness,filling density,printing speed,and printing temperature).The combination of process parameters with the smallest size error and the best mechanical properties was obtained.The bending and compression properties of the polylactic acid protective cover samples were tested.The optimal structure of the protective cover was obtained by comprehensively analyzing the test data and finite element simulation results.