脊椎インプラントのロープロファイル化の評価

抄録

Most of spinal implants are made in foreign countries and do not necessarily match a build of Japanese. Therefore the form of the implant is confirmed by the appearance and QOL becomes the problem. Thus there is the problem that fitting force decreases while the use of a small implant device is desirable. In this study, the downsizing of the implant device namely a low profile examined it. The test materials made a set screw and a screw socket specimen of different 3Type of dimensions using Ti-6Al-4V. A removal torque value was measured after tightening of the set screw (Static load) and after give load to a rod repeatedly (dynamic load). The set screw was observed after examination using a SEM. The removal torque value decreased the removal torque value of Type 2 in comparison with Type 1. On the other hand, Type3 which assumed the same number of the threads Type1 was equal to a removal torque value of Type 1. As a result of observed the thread surface of the set screw, plastic deformation and an abrasion trace were observed. In addition, an opening of the upper screw socket was accepted in a fit state, and this situation was easy to loosen set screw.