System for optimizing anchoring force

• US 20050277983A1
• Filed: 06/09/2004
• Published: 12/15/2005
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: USGI Medical, Inc.
• Original Assignee: USGI Medical, Inc.
• Inventors: Saadat, Vahid, Ewers, Richard C., Maahs, Tracy D., Michlitsch, Kenneth J., Khairkhahan, Alex
• Granted Patent: US 7,695,493 B2
• Time in Patent Office: Days
• US Class Current: 606/215
• CPC Class Codes: A61B 17/0401 Suture anchors, buttons or pledgets, i.e. means for attaching sutures to bone, cartilage or soft tissue; Instruments for applying or removing suture anchors A61B17/0642 takes precedence; fixation devices for tendons or ligaments A61F2/0811
• CPC Class Codes: A61B 17/0469 Suturing instruments for use in minimally invasive surgery, e.g. endoscopic surgery
• CPC Class Codes: A61B 17/0482 Needle or suture guides guides for drills, pins or wire A61B17/17; for puncturing needles A61B17/3403
• CPC Class Codes: A61B 17/0644 penetrating the tissue, deformable to closed position
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2017/0454 the anchor being crimped or clamped on the suture
• CPC Class Codes: A61B 2017/0464 for soft tissue
• CPC Class Codes: A61B 2017/0496 for tensioning sutures
• CPC Class Codes: A61B 2017/06052 Needle-suture combinations in which a suture is extending inside a hollow tubular needle, e.g. over the entire length of the needle hollow suture needles A61B2017/061
• CPC Class Codes: A61B 2090/037 with a frangible part, e.g. by reduced diameter

Abstract

Systems for optimizing anchoring force are described herein. In securing tissue folds, over-compression of the tissue directly underlying the anchors is avoided by utilizing tissue anchors having expandable arms configured to minimize contact area between the anchor and tissue. When the anchor is in its expanded configuration, a load is applied to the anchor until it is optimally configured to accommodate a range of deflections while the anchor itself exerts a substantially constant force against the tissue. Various devices, e.g., stops, spring members, fuses, strain gauges, etc., can be used to indicate when the anchor has been deflected to a predetermined level within the optimal range. Moreover, other factors to affect the anchor characteristics include, e.g., varying the number of arms or struts of the anchor, positioning of the arms, configuration of the arms, the length of the collars, etc.

Claims

1. 1. A system for loading an anchor for placement against a tissue surface, comprising:

an anchor body having a delivery configuration and an expanded configuration adapted for placement against the tissue surface; and

a loading mechanism in communication with the anchor body, wherein the loading mechanism is adapted to indicate a loading condition upon the anchor body.

2. The system of claim 1 further comprising a length of suture extending between the anchor body and the loading mechanism.

3. The system of claim 2 further comprising a locking mechanism adapted to pass the anchor body in a first direction relative to the length of suture upon application of a cinching force.

4. The system of claim 3 wherein the locking mechanism is further adapted to impart a locking force upon the length of suture when the anchor body is urged in a second direction opposite to the first direction, and wherein the locking force is greater than the cinching force.

5. The system of claim 1 wherein the anchor body is adapted to be delivered through a hollow member for placement against the tissue surface.

6. The system of claim 5 wherein the hollow member comprises a needle.

7. The system of claim 1 wherein the anchor body comprises a basket-type anchor.

8. The system of claim 1 wherein the anchor body comprises a plurality of reversibly deformable arms extending between a proximal collar and a distal collar.

9. The system of claim 8 wherein each of the deformable arms are adapted to contact the tissue surface.

10. The system of claim 1 wherein the anchor body comprises a plurality of deformable arms which are configured to define a space between adjacent arms for minimizing contact between the anchor body and the tissue surface.

11. The system of claim 1 wherein the anchor body is comprised of a shape memory or superelastic alloy.

12. The system of claim 1 wherein the anchor body is comprised of nitinol.

13. The system of claim 1 wherein the loading condition is indicative of a deformation state of the anchor body.

14. The system of claim 1 wherein the loading mechanism is further adapted to indicate a predetermined loading condition upon the anchor body.

15. The system of claim 14 wherein the predetermined loading condition is indicative of a deformation range where the anchor body exerts a substantially constant force upon the tissue surface.

16. The system of claim 1 wherein the loading mechanism comprises a post extending from the anchor body, the post being configured to inhibit deformation of the anchor body beyond a predetermined limit.

17. The system of claim 1 wherein the loading mechanism comprises:

a first member defining a first region with a first frictional coefficient;

a second member defining at least a second region with a second frictional coefficient different from the first frictional coefficient,

wherein the first member and the second member are adapted to slide relative to one another such that a first frictional force is generated by contact between the first region and the second region, and

wherein a change in the first frictional force is indicative of a predetermined loading condition upon the anchor body.

18. The system of claim 17 wherein the second member further defines a third region with a third frictional coefficient different from the second frictional coefficient.

19. The system of claim 17 wherein the first member comprises an elongate tubular member.

20. The system of claim 17 wherein the second member comprises an outer member circumferentially disposed over the first member.

21. The system of claim 17 wherein the first member or the second member further comprises a stop adapted to limit a longitudinal motion between the respective members.

22. The system of claim 1 wherein the loading mechanism comprises a spring member having a predetermined spring coefficient.

23. The system of claim 1 wherein the loading mechanism comprises a strain gauge adapted to measure a longitudinal deformation of a tensioned region, the deformation being indicative of the loading condition upon the anchor body.

24. The system of claim 23 further comprising a monitor in communication with the strain gauge, the monitor being adapted to indicate a predetermined loading condition upon the anchor.

25. The system of claim 1 wherein the loading mechanism comprises a stop located upon the anchor body, the stop being configured to inhibit deformation of the anchor body beyond a predetermined limit.

26. The system of claim 1 wherein the loading mechanism comprises a fuse member adapted to break when a predetermined loading condition is reached, thereby inhibiting deformation of the anchor body beyond a predetermined loading condition.

27. The system of claim 26 wherein the fuse member comprises a length of material having a known failure strength.

28. The system of claim 26 wherein the fuse member comprises a notched material.

29. The system of claim 1 further comprising a covering or coating disposed at least partially over the anchor body.

30. A method for loading an anchor for placement against a tissue surface, comprising:

positioning the anchor relative to the tissue surface;

applying a load to the anchor such that the anchor is configured into a partially compressed state against the tissue surface; and

adjusting the load such that the anchor exerts a substantially constant force upon the tissue surface.

31. The method of claim 30 wherein positioning the anchor comprises deploying the anchor via a hollow needle against the tissue surface.

32. The method of claim 30 wherein positioning the anchor comprises configuring the anchor from a delivery configuration to an expanded configuration.

33. The method of claim 30 wherein positioning the anchor comprises deploying a plurality of deformable arms against the tissue surface such that a space is defined between adjacent arms for minimizing contact between the anchor and the tissue surface.

34. The method of claim 30 wherein applying a load to the anchor comprises applying the load to a length of suture.

35. The method of claim 34 further comprising imparting a locking force upon the length of suture such that the locking force inhibits the anchor from relaxing from its compressed state.

36. The method of claim 30 wherein adjusting the load comprises applying a predetermined loading condition upon the anchor.

37. The method of claim 30 wherein adjusting the load comprises applying the load until the anchor exerts the substantially constant force upon the tissue surface over a range of deflection of the anchor.

38. The method of claim 30 wherein adjusting the load comprises applying the load until a change in the load is detected.

39. The method of claim 30 wherein adjusting the load comprises detecting the substantially constant force via a spring member having a predetermined spring coefficient.

40. The method of claim 30 wherein adjusting the load comprises detecting the substantially constant force via a strain gauge adapted to measure a longitudinal deformation of a tensioned region.

41. The method of claim 30 wherein adjusting the load comprises detecting the substantially constant force via a fuse member adapted to break when the constant force is reached.