The Research On Acetabular Anterior Column Nailing Guide Instrument And The Channel Planning

Acetabular anterior pin sight device has the function of helping doctors to complete the nail channel planning and guiding the screw accurately during operation.The high quality sight device will make the complex anterior column fixation simple and safe.The key to the design and manufacture of individualized nail sight device lies not only in its reasonable structure and structure technology,but also in its scientific,accurate and efficient planning.The reasonable structure of the sight device for the front post of the acetabular nail should have the characteristics of accurate positioning,sufficient strength and stiffness,and the pursuit of minimally invasive device,and the preparation of the sight device with reasonable structure and technology should be based on the 3D printing process and its technological parameters.In order to ensure the geometric accuracy of the positioning surface,highlight the advantages of flexible manufacturing and agile manufacturing,and improve the planning quality and efficiency of the nail setting channel of the sight device by means of CAD technology,In order to obtain the best biomechanical performance by selecting the largest standard screw in order to obtain the best biomechanical performance,and to respond quickly to the operation request,To provide reliable technical guarantee and technical and economic basis for promoting the clinical application of the sight device.In this paper,the present method of internal fixation of acetabular anterior column nail and the method of channel planning are described.It is pointed out that poor navigation accuracy is the most difficult problem in this operation,but the original positioning accuracy is not high and the stability of positioning accuracy is poor.Secondary injury to patients,poor planning quality and low efficiency of nail placement channel are the bottleneck problems that hinder the clinical application of acetabular anterior post nail sight device.In this paper,the theoretical and experimental research on the above problems is carried out.The main research contents and results are as follows:(1)A method of removing the posterior column of the hip model along the direction parallel to the iliac pubic line in the Mimics environment and through the center of the acetabular fossa was proposed,and the accurate point set of the front column centerline was obtained by fitting the centerline function.In this paper,a method of fitting out the least square straight line of the center line set of the acetabular anterior column under UG Imageware environment and determining the orientation of the pin is presented.(2)The 11 positive sections of the least square line are described,and the positive cross section of the center point of the acetabular pit must be included as the basis for accurate planning of the diameter of the channel and the basis of safety evaluation.A method of setting up the nail channel for determining the location of the axis of the channel with its center position.(3)Two methods to obtain the maximum diameter of the safe channel are proposed,and the parameter comparison and the virtual simulation of pin setting effect are carried out.The results show that the maximum diameter of the inner circle and the short axis size of the maximum inner ellipse can be used as the diameter of the safe passage,although the former is larger than the latter in this study.But it is not proved that the former is superior to the latter,and the effective thread length,the amount of bone excision and the neuter of the channel axis should be considered for comprehensive evaluation.(4)Based on the characteristics of FDM-3D printing technology,the structure and structure of the sight device are designed,and the individualized front-acetabular pin sight device is made.In the sight device,the matching experiment of the positioning surface between the target hip bones and the drilling experiment of the drill bit diameter with the large diameter of the screw was carried out on the acetabular anterior column.The results show that the planning technique has obvious advantages in planning quality and ease of operation,compared with the current method of acetabular anterior pin channel planning,and the structure of the sight device is ergonomics and can be based on the FDM-3D printing technology is made with high quality and efficiency;The sight device and the target hip have a good effect of sticking and matching,and the accuracy of positioning in use is good;The borehole channel does not break the wall in the front column.There is no obvious position deviation in the center of the passage at the minimum cross section.