EP-4736791-A2 - COUPLING JOINTS ON TUBULAR SPIRALLING LOOPS OF A STEERABLE ARM FOR AN ENDOSCOPE INSTRUMENT CHANNEL

Abstract

A steerable arm configured for the biopsy channel of an endoscope comprising a continuum structure of a resilient material in the form of a hollow tubular member. The tubular member comprising a tubular coil 707 of spiralling loops having a column of coupling joints on opposite sides of the tubular coil. Each coupling joint between adjacent loops comprises a round neckless head for a male part 1401 and a cradle for a female part 1403. The tubular member having a curvature that changes when a loop on the distal end of the coil is pulled on by a wire to close. The continuum structure providing a bias such that the curvature change revers when the pull is released.

Inventors

• KWOK, Ka Wai
• HE, Zhuoliang
• WANG, XIAOMEI
• HO, Justin Di-Lang
• FANG, Ge
• WANG, KUI

Assignees

• Versitech Limited

Dates

Publication Date

20260506

Application Date

20220121

Claims (5)

1. A steerable arm configured for the biopsy channel of an endoscope, comprising a continuum structure of a resilient material in the form of a hollow tubular member, the tubular member comprising a tubular coil of spiralling loops having a column of coupling joints on opposite sides of the tubular coil; each coupling joint being between adjacent loops, a round neckless head for a male part on one of the adjacent loops and a cradle for a female part on the other of the adjacent loops; a wire; the tubular member having a curvature that changes when a loop on a distal end of the tubular coil is pulled on by the wire to close; the continuum structure providing a bias such that the curvature change reverses when the pull is released.
2. A steerable arm, as claimed in claim 1, the tubular coil being in two sections wherein the curvature change of the each section is in a different plane.
3. A steerable arm, as claimed in claim 1 or 2, wherein the tubular member is curved in a rest state, such that there is a concave side and a convex side to the tubular member; the edges of the loops on the convex side are spaced apart; the edge of each of the loops on the concave side abutting the edge of each adjacent loop.
4. A steerable arm, as claimed in claim 3, wherein the loops have different spiral pitches and/or spacing variations along different parts of the steerable arm, in order to provide the different parts with different flexibility.
5. A steerable arm, as claimed in claim 1, further comprising a transmission tube the steerable arm is arranged at the distal end of the transmission tube; the transmission tube containing a channel in which the wire is threaded; the proximal end of the wires connected to knobs and/or levers for pulling on the wire; such that the curvature changes when the distal end of the tubular member is pulled on by the wire at the proximal end of the transmission tube.

Description

TECHNICAL FIELD OF THE INVENTION The invention relates to the field of endoscopic surgical instruments. BACKGROUND Gastrointestinal (GI) cancers are the most common cancers worldwide. According to World Health Organization (WHO) cancer statistics, colorectal and gastric cancers are respectively the second and third most common cause of cancer related deaths globally, which amount to 862,000 and 783,000 respectively in 2018. While advanced GI cancers are difficult to cure, early GI cancers carry a significantly better prognosis. The 5-year survival for GI cancers at an early stage is more than 90% worldwide. Conventional treatment for GI cancers is surgery, which involves resection and anastomosis, and is associated with significant morbidity and mortality rates. The preferred methods of surgery of the gastrointestinal (GI) tract include directing surgical instruments through the instrument/biopsy channels of an endoscope. A flexible endoscope is inserted through the mouth into the stomach to reach the target location, or from the anus up into the large intestine to reach the target location, with the distal end of the endoscope steered by the surgeon using a control handle on the proximal end of the endoscope. The endoscope has at least one biopsy channel into which a long, flexible instrument with a surgical tool at the distal tip is inserted from the proximal end of the endoscope. The most commonplace flexible endoscopes are made by Olympus, and have biopsy channel diameters as large as 3.7 mm, but which may be as small as 2.8 mm and lower. Medrobotics proposes a semi-robotic robotic endoscope with channels for manual surgical instruments (described in US10016187B2). The diameter of the surgical instrument is assembled from many discrete joints to allow articulation when pulled by a pair of pair of antagonistic wires (two wires on opposite sides pulling in opposite directions). To bend a joint in one direction, one wire must be pulled, while the other wire must be released or pushed. The discrete joints are complex to design and assemble, and necessitate a wide 4-mm thick diameter. Hence, a major disadvantage of this surgical instrument is that it does not fit into the biopsy channel in the commonplace flexible endoscopes. Endomaster proposes a similar robotic surgical instrument, which is also assembled from discrete joint-based mechanisms (described in US20210186309A1) that suffer from the same disadvantages. Lumendi proposes an endoscopic surgical instrument that comprises a flexible backbone fabricated from a single body of flexible material, e.g. a nickel titanium (nitinol) tube, with unconnected, discrete slots cut into and along the side of the tube (described in US20200305906A1). The straight tube can be bent to either direction by pulling wires affixed to the respective side of the tube. Again, this design requires complex manipulation in pulling on one wire while releasing the opposite wire. Furthermore, this surgical instrument is also too thick to be useable with the biopsy channels in commonplace endoscopes and must be used with their proprietary accessory system. Endotheia proposes a surgical instrument that can be used with the commonplace endoscope, described in US10441371B2. This design comprises nested concentric nitinol tubes, which are each pre-curved. These tubes have an overall diameter that is capable of extending through the biopsy channel in the commonplace endoscope. To bend the surgical instrument towards a target location, each of the nested tubes is extended to a suitable extent to create the required curvature. There is no need of wires to bend the tubes. However, the extent to which each curved tubes should extend requires complex computation, which makes it rather necessary for software and robotic control, and manual override is implausible even when the situation might call for it. Furthermore, the lifting force of the thin tubes is too weak for some procedures. Also, the tubes cannot provide a sharp bend, and the endoscope has to be placed relatively far from the target site in order for the tubes to extend far enough to provide sufficient curvature. As a result, the camera on the tip of the endoscope may be too far from the distal end of the surgical instrument to provide good visualization of the operation; the lateral and vertical reach of the instrument may be limited if the target site is too near the tip of endoscope. Therefore, it is desirable to propose a surgical instrument that provides dexterous tissue manipulation while being suitable for use with commonplace endoscopes, and which provides a possibility of better control to the surgeon. STATEMENT OF INVENTION In a first aspect, the invention proposes a steerable arm for use in endoscopic surgical procedures, comprising: a tubular member having a proximal end and a distal end; distal end suitable for being fitted with a surgical end effector; the tubular member being made of a resilient material; a wire extend