Endoscopic high-frequency snare

• US 20050131424A1
• Filed: 11/15/2004
• Published: 06/16/2005
• Est. Priority Date: 12/10/2003
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Ouchi, Teruo
• Granted Patent: US 7,387,632 B2
• Time in Patent Office: Days
• US Class Current: 606/113
• CPC Class Codes: A61B 17/32056 Surgical snare instruments for removing or smashing calculi A61B2017/2212; tonsillotomes A61B17/26
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00269 endoscopic mucosal resection EMR
• CPC Class Codes: A61B 2018/1407 Loop
• CPC Class Codes: A61B 2018/141 Snare
• CPC Class Codes: A61B 2018/1422 Hook
• CPC Class Codes: A61B 2018/1475 Electrodes retractable in or deployable from a housing

Abstract

A snare for an endoscope includes a flexible sheath, a control wire movable within the flexible sheath, and a snare loop connected to an end of the control wire, wherein when the control wire is axially advanced, the snare loop projects from the flexible sheath and expands into a loop shape, whereas when the control wire is axially retracted, the snare loop retracts into the flexible sheath and is folded into a closed shape. A resilient wire which forms the snare loop includes a hook portion protruding in a lateral direction of the snare loop. The resilient wire includes a biasing portion which biases the distal end of the resilient wire from a tip end to a base end of the hook portion to press the distal end of the resilient wire against an inner surface of the flexible sheath when the resilient wire is retracted.

Claims

1. A snare for an endoscope, comprising:

a flexible sheath;

a control wire axially movable within said flexible sheath; and

a snare loop connected to a distal end of said control wire, wherein when said control wire is axially advanced, said snare loop projects from a distal end of said flexible sheath and expands into a loop shape due to resiliency of said snare loop, whereas when said control wire is axially retracted, said snare loop retracts into said distal end of said flexible sheath and is folded into a closed shape,

wherein a resilient wire which forms said snare loop includes a hook portion at a distal end of said resilient wire, said hook portion protruding in a lateral direction of said snare loop, and

wherein said resilient wire includes a biasing portion which biases said distal end of said resilient wire in a direction from a tip end to a base end of said hook portion to press said distal end of said resilient wire against an inner peripheral surface of said flexible sheath in a state where said resilient wire is retracted into said distal end of said flexible sheath.

2. The snare according to claim 1, wherein said hook portion is formed by bending a portion of said resilient wire in a vicinity of said distal end thereof so that said hook portion protrudes in said lateral direction of the snare loop.

3. The snare according to claim 1, wherein said biasing portion is formed by bending a portion of said resilient wire in a vicinity of said distal end of said resilient wire so that said biasing portion is resiliently in pressing contact with an inner peripheral surface of said flexible sheath to bias said distal end of said resilient wire in said direction from said tip end to said base end of said hook portion in a state where said resilient wire is retracted into said distal end of said flexible sheath.

4. The snare according to claim 1, wherein said biasing portion is formed by forming said resilient wire in an arc shape as a whole so that said biasing portion is resiliently in pressing contact with an inner peripheral surface of said flexible sheath to bias said distal end of said resilient wire in said direction from said tip end to said base end of said hook portion in a state where said resilient wire is retracted into said distal end of said flexible sheath.

5. The snare according to claim 1, wherein a length of said hook portion is determined so that said tip end of said hook portion is positioned in a close vicinity of an outer edge of said flexible sheath in a state where said resilient wire is retracted into said distal end of said flexible sheath.

6. The snare according to claim 1, wherein said flexible sheath and said control cable are made of an insulating material and a conductive material, respectively.

7. The snare according to claim 5, wherein said length of said hook portion substantially corresponds to an outside diameter of said flexible sheath minus a wall thickness of said flexible sheath.

8. The snare according to claim 1, wherein said resilient wire includes two resilient wires extending between two mutually secured portions,

wherein said hook portion and said biasing portion are formed on one and the other of said two resilient wires, respectively.

9. The snare according to claim 2, wherein said hook portion is formed by bending said portion of said resilient wire in a substantially L shape.

10. A snare for an endoscope, comprising:

a flexible sheath;

a control wire axially movable within said flexible sheath;

a snare loop made of at least one resilient wire and fixed to a distal end of said control wire, said snare loop expanding and becoming narrow when said control wire is advanced and retracted to make said snare loop project and retract from and into a distal end of said flexible sheath, respectively;

a hook portion formed on said resilient wire at a distal end thereof; and

a biasing portion, formed on said resilient wire between said hook portion and another end of said resilient wire which is connected to said distal end of said control wire, for biasing said distal end of said resilient wire in a direction from a tip end to a base end of said hook portion to press said distal end of said resilient wire against an inner peripheral surface of said flexible sheath in a state where said resilient wire is retracted into said distal end of said flexible sheath.