Snare mechanism for surgical retrieval

• US 20090112244A1
• Filed: 10/24/2008
• Published: 04/30/2009
• Est. Priority Date: 10/25/2007
• Status: Active Grant

• Current Assignee: Pfm Medical AG
• Original Assignee: Pfm Medical AG
• Inventors: Freudenthal, Franz
• Granted Patent: US 8,628,540 B2
• Time in Patent Office: Days
• US Class Current: 606/167
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 17/32056 Surgical snare instruments for removing or smashing calculi A61B2017/2212; tonsillotomes A61B17/26
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/2212 having a closed distal end, e.g. a loop

Abstract

A snare device for capturing an object or for cutting tissue in the body of a human or animal. The device employs at least one twisted loop of memory shaped material housed in and movable relative to a hollow member such as a catheter. The device and method of employment is particularly well adapted for retrieving objects from internal body cavities and cutting tissue therein.

Claims

1. A snare device for capturing an object and/or for cutting a tissue comprising at least one twisted loop of memory shaped material, the loop being housed in and movable relative to a hollow member, especially a catheter, to be deployed and retracted into the hollow member,

characterized in that

a locking wire is provided for being translated through the at least one loop to capture an object between part of the loop and the locking wire extending through the loop and/or for puncturing the tissue and/or for cutting the tissue by the loop as combined with the locking wire the locking wire piercing the tissue at a second aperture distant from a first aperture at least part of the loop extends through the locking wire being translated through the loop and engaging with the same and retracting the loop into the hollow member such that the tissue is cut between both of the apertures.

2. The device as claimed in claim 1, wherein two loops are provided one of which being the smaller one and one being the larger one the loops being connected via a twisting area.

3. The device as claimed in claim 2, wherein when deployed the plane of the smaller loop is provided with an angle α

of about 120°

to 170°

, especially about 150°

, to the axis of the hollow member or the locking wire, respectively, for capturing of an object.

4. The device as claimed in claim 2, wherein the plane of the larger loop is provided with an angle (β

) of about 10°

to 60°

, especially about 30°

, to the plane of the smaller loop for the capturing of an object.

5. The device as claimed in claim 3, wherein the plane of the larger loop is provided with an angle (β

) of about 10°

to 60°

, especially about 30°

, to the plane of the smaller loop for the capturing of an object.

6. The devices claimed in claim 1, wherein for cutting a tissue the plane of the smaller loop and the larger loop can be provided essentially parallel to one another to be placed on both surfaces of the tissue.

7. The device as claimed in claim 1, wherein the extent of the smaller loop between the distal end of the hollow member, especially a catheter or a sheath surrounding the proximal ends of the loop can be adapted or changed to define the length of the cut to be provided in the tissue.

10. The device as claimed in claim 1, wherein the leading edge of the loop is a pointed portion being provided such that it can be used for puncturing the tissue.

13. The device as claimed in claim 1, wherein one or more wires, especially two wires, extend proximally from the proximal end of the at least one loop.

16. The device as claimed in claim 13, wherein a sheath is provided extending to the proximal end of the at least one loop and surrounding the wire or wires the sheath being straight and/or angled and/or curved in a distal area.

19. The snare device as claimed in claim 1,

characterized in that

two loops connected by twisting and a sheath are provided the sheath extending to the proximal end of the at least one loop, surrounding part of a wire or wires of the loop or loops and being angled or curved and the loops are deployable such that the smaller one extends between the halves of the larger loop.

22. The device as claimed in claim 1, wherein a marker is provided at the loop, especially the smaller loop, for making the loop visible under visualization means.

8. A snare device for capturing an object and/or for cutting a tissue comprising at least one twisted loop of memory shaped material, the loop being housed in and movable relative to a hollow member, especially a catheter, to be deployed and retracted into the hollow member,

characterized in that

two loops are provided connected by twisting, one of the loops being the smaller one and one being the larger one and wherein the plane of the smaller loop is provided with an angle (α

) of about 120°

to 170°

to the axis of the hollow member and the plane of the larger loop is provided with an angle (β

) of about 10°

to 60°

to the plane of the smaller loop.

9. The device as claimed in claim 8, wherein the plane of the smaller loop is provided with an angle (α

) of about 150°

to the axis of the hollow member and the plane of the larger loop is provided with an angle (β

) of about 30°

to the plane of the smaller loop.

11. The device as claimed in claim 8, wherein the leading edge of the loop is a pointed portion being provided such that it can be used for puncturing the tissue.

14. The device as claimed in claim 8, wherein one or more wires, especially two wires, extend proximally from the proximal end of the at least one loop.

17. The device as claimed in claim 14, wherein a sheath is provided extending to the proximal end of the at least one loop and surrounding the wire or wires the sheath being straight and/or angled and/or curved in a distal area.

20. The snare device as claimed in claim 8,

characterized in that

two loops connected by twisting and a sheath are provided the sheath extending to the proximal end of the at least one loop, surrounding part of a wire or wires of the loop or loops and being angled or curved and the loops are deployable such that the smaller one extends between the halves of the larger loop.

23. The device as claimed in claim 8, wherein a marker is provided at the loop, especially the smaller loop, for making the loop visible under visualization means.

12. A snare device for capturing an object and/or for cutting a tissue comprising at least one twisted loop of memory shaped material, the loop being housed in and movable relative to a hollow member, especially a catheter, to be deployed and retracted into the hollow member, wherein one or more wires, especially two wires, extend proximally from the proximal end of the at least one loop.

15. The device as claimed in claim 12, wherein a sheath is provided extending to the proximal end of the at least one loop and surrounding the wire or wires the sheath being straight and/or angled and/or curved in a distal area.

21. The snare device as claimed in claim 12,

characterized in that

two loops connected by twisting and a sheath are provided the sheath extending to the proximal end of the at least one loop, surrounding part of a wire or wires of the loop or loops and being angled or curved and the loops are deployable such that the smaller one extends between the halves of the larger loop.

24. The device as claimed in claim 12, wherein a marker is provided at the loop, especially the smaller loop, for making the loop visible under visualization means.

18. A snare device for capturing an object and/or for cutting a tissue comprising at least one twisted loop of memory shaped material, the loop being housed in and movable relative to a hollow member, especially a catheter, to be deployed and retracted into the hollow member,

characterized in that

two loops connected by twisting and a sheath are provided the sheath extending to the proximal end of the at least one loop, surrounding part of a wire or wires of the loop or loops and being angled or curved and the loops are deployable such that the smaller one extends between the halves of the larger loop.

25. The device as claimed in claim 18, wherein a marker is provided at the loop, especially the smaller loop, for making the loop visible under visualization means.

26. A method for retrieving an object from a human or animal body employing a snare device deployable from a hollow member, especially a catheter, and retractable into the hollow member, the snare device comprising a twisted loop with at least two loops and a twisted area connecting both loops when deployed in the side view the planes of the loops are angled one to the other and to the direction of the hollow member, and comprising a locking wire housed in the hollow member, comprising the steps of:

encircling the object by the curved area such that both loops are provided next to the object,

extending the locking wire through at least one of the loops,

retracting the loops into the hollow member such that the object is held between part of the loops and the locking wire, and

retracting the locking wire together with the loops and the held object into the hollow member.

27. A method for cutting a tissue by use of a snare device deployable from a hollow member, especially a catheter, and retractable into the hollow member, the snare device comprising a twisted loop having at least two loops and a twisted area connecting both loops when deployed in the side view the planes of the loops are angled or parallel one to the other and the twisted area is radially distant from the hollow member, and comprising a locking wire housed in the hollow member, comprising the steps of:

piercing the tissue with a first aperture and extending the at least one loop through the first aperture to place the twisted area generally within the first aperture,

piercing the tissue with a second aperture and extending the locking wire through the second aperture and through the at least one loop the locking wire extending as a prolongation of the hollow member,

retracting the at least one loop into the hollow member and thereby cutting the tissue with a cut between both apertures.