The Design And Mechanical Study Of A Novel Internal Fixation Screw For Osteoporosis

Pedicle screw fixation has become the most commonly used fixation technique for spinal surgery.In recent years,China's population aging problem is increasing,osteoporosis patients more and more because of spinal disease need for surgical treatment.However,a serious impact on the bonding strength of osteoporosis and bone screw interface,and decrease the stability of the gripping force of the screw,resulting in loosening of the screw,exits,eventually leading to implant failure.Therefore,how to effectively improve the stability of the pedicle screw under the conditions of osteoporosis,to prevent the loosening of the screw to become the primary problem of spinal surgery to be resolved.In order to solve the above problems,the traditional pedicle screw fixation technology was improved.In this paper,through the use of cortical bone screw trajectory technology developed a suitable for patients with osteoporosis internal fixation screw,new screw insertion channel and cortical bone interface has the advantages of larger,stronger control force,such as small trauma,so as to reduce the risk of failure of internal fixation.The main contents and conclusions of this paper are as follows:(1)Anatomical study on the design of a new type of internal fixation screw for osteoporosis.Through searching the related literatures of cortical bone trajectory screw,the length and diameter of the new type of osteoporotic internal fixation screw were determined according to the collected literature data.(2)Finite element analysis of a new type of internal fixation screw for osteoporosis.The finite element analysis of three screws with different parameters was carried out by software,the force of screw in vertebral body was simulated,and the parameters of screw with larger holding force were optimized,which provided the theoretical basis for screw design.(3)Design and development of a new type of internal fixation screw for osteoporosis.Innovative design of the specific structure,new screw thread using double lead design,screw insert speed faster.The characteristics of titanium alloy materials and screws with good biocompatibility are introduced.(4)Biomechanical study of new internal fixation screw for osteoporosis: Compression bending fatigue,axial pull out force test according to YY / T 0857-2011 and YY / T 0119.2-2014 medical device industry standard.mechanical performance test,compared with the traditional pedicle screw.(5)The fatigue strength of the new internal fixation screw system for osteoporosis was 280 N,and the fatigue strength of the traditional pedicle screw system was 300 N.There was no difference in the performance of the new internal fixation screw system for osteoporosis compared with the traditional pedicle screw system.The axial load of the new internal fixation screw system for osteoporosis is 2349 N,while the peak load of the traditional pedicle screw system is 1966 N.The new internal fixation screw for osteoporosis increased the axial pullout force by 19% compared with the traditional pedicle screw.Successful development of new internal fixation screw system for osteoporosis,the innovative design can retain the original stable structure of the lumbar to increase the biomechanical stability of the fusion segment.The new type of osteoporotic fixation screw has a more reliable initial fixation performance than the traditional pedicle screw.The new internal fixation screw system is expected to become a simple,safe and effective osteoporosis fixation system.