Design and Modeling of a Novel Flexible Surgical Instrument Applicable in Minimally Invasive Surgery

Abstract

Some of laparoscopic surgeries maneuvers, suturing for instance, require precise and dexterous movements. These surgeries
are difficult to perform, as they require using rigid instruments. So, multi degrees of freedom hand held instruments have been
developed to increase movement dexterity. In this paper, design and modeling of a novel surgical hand held flexible instrument is
presented. This instrument consists of three main components, which are wrist mechanism, cable and back end mechanism, and
end effector mechanism. The proposed surgical instrument has 5DOF with 8 mm diameter and has bending range of -90 to +90
degrees in horizontal and vertical directions. The designed instrument is wire actuated using steel cables. In order to control the
flexible instrument, a servo system is constructed. Main advantages of this surgical instrument are its low weight and the ability of
providing sufficient degrees of freedom for movement in complex spaces. Kinematic analysis of the designed instrument results
in relative orientation and position of the end effector to the handle. The proposed instrument can improve the issue of lack of
dexterity in the complicated spaces concerning minimally invasive surgeries.