Invisible Object Locating System for Fracture Surgery by Using Eddy Current

Abstract

This report describes an eddy current system for locating distal transverse screw holes of an intramedullary nail. In fracture surgery, screw holes on an intramedullary nail are in invisible situation. Although conventional X-ray methods can visualize screw holes in bone, they pose a danger due to X-ray exposure. Therefore, a system to fmd screw holes without X-ray exposure is required. We solved this problem using an eddy current system and applying a method that calculates local minimum positions of a searching signal obtained by the eddy current system. Shape characteristics of screw holes were revealed in the waveform and amplitude of the searching signal. As a result, the screw hole positions could be identified with the smallest error of 0.99 mm when the distance between the probe and the intramedullary nail was 8 mm. The screw was successfully inserted. to the screw holes in this accuracy.

Keywords:

• Eddy Current
• Orthopedic Surgery
• Intramedullary Nail