360 degrees Bending Mechanism Using Slacken SMA Wires for Transurethral Lithotripsy

Abstract

During urethral lithotripsy, a flexible ureteroscope is inserted into the kidney through urethra and bladder. The calculus inside the kidney is crushed by laser transmitted through an optical fiber which is inserted through channel of the ureteroscope. Because of the complex and elaborate structure in the kidney, sometimes it is hard for an ureteroscope which has a fixed optical fiber to reach the targeted calculus. In order to solve this problem, an actuator device was fabricated which has the ability to control the laser irradiation position precisely in the view of ureteroscope by bending the optical fiber with SMA (Shape Memory Alloy) wires. In this study, the structure of the device was improved to enable bending in any direction by slacken SMA wires. The new performances of it such as bending angle and response time were measured to confirm the functions.