Rigid-Flexible Outer Sheath Model Using Slider Linkage Locking Mechanism and Air Pressure for Endoscopic Surgery

Abstract

Abstract. The objective of this paper is to develop an outer sheath for flexible endoscopic manipulators. This sheath can switch two states including flexible and rigid, and make a rigid curved path for inserting manipulators. The flexible mode can be curved into a required shape. The rigid mode can hold the shape of the sheath, and then keep the path for instruments. Through the managed path, the flexible manipulators become easy to reach the target. We proposed a serial multi joint model to realize the flexible mechanism. This model is composed of a set of frame units which are connected serially. Each unit can be rotated to a given angle around the center of the joint. We developed a sliderlink mechanism and a gear stopper controlled by air pressure for rigid mode. We designed and fabricated the prototype with a diameter of 16mm and length of 290mm. The experiment showed that the device could be switched from the flexible mode to the rigid mode when the air pressure was over 150kPa, and each joint could hold its angle against the maximum 400mNm. The phantom experiment showed that the flexible devices are possible to transmit the wire tension to the endpoint of the manipulator without changing the curving shape with by the developed outer sheath device.

Development of a medical robot system for minimally invasive surgery

“…To overcome the dexterity constraints in MIS, various attempts have been developed to enhance surgeons' control of the position and orientation of surgical instruments. There are planar and spatial linkages (16)(17)(18)(19), parallel wrists (20,21), serial articulated wrists (22)(23)(24) and, recently, snake-like devices (16,(24)(25)(26)(27)(28)(29)(30)(31)(32). However, a typical solution to the problems of a combination of size, sterilization and dexterity is to configure surgical instruments with a wrist-like mechanism (hereafter referred to as a 'wrist').…”

Natural orifice transluminal endoscopic surgery with a snake‐mechanism using a movable pulley

“…Several approaches with overtubes have been studied. One approach uses a flexible tube that can mechanically shift from being rigid to being flexible . The overtube is inserted manually similar to that in endoscopy and subsequently fixed by a locking mechanism.…”

Configuration comparison for surgical robotic systems using a single access port and continuum mechanisms

“…Both procedures drew quite a bit of attention in the past a few years because of their potentials in further reducing postoperative complications to traditional laparoscopic MIS (Minimally Invasive Surgery) [4][5][6]. Looking at the promising future of the SPA and the N.O.T.E.S surgeries, robotics researchers constructed various robotic systems to assist the SPA surgeries [7][8][9][10] and the N.O.T.E.S procedures [11][12][13].…”