Axial-Force Limiting Torque Wrench for Use with Implantable Medical Devices

• US 20100274230A1
• Filed: 02/17/2010
• Published: 10/28/2010
• Est. Priority Date: 04/23/2009
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Hansen, John E., Swanson, Lawrence D., Edgell, John M., Chavan, Abhi V.
• Granted Patent: US 8,430,868 B2
• Time in Patent Office: Days
• US Class Current: 606/1
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections

Abstract

Embodiments of the invention are related to tools for coupling leads to header assemblies for implantable medical devices, amongst other things. A wrench is configured so that if an axial force exceeding a first threshold is applied to a handle housing, then the housing handle will rotate with respect to a shaft. Other embodiments are also included herein.

Claims

1. A wrench for coupling a set screw to a medical device comprising:

a shaft comprising an interface end that is configured to be received in a set screw depression defined on a head of a set screw, the shaft defining an axis of the wrench; and

a handle housing;

wherein the wrench is configured so that if an axial force exceeding a first threshold is applied to the handle housing, then the housing handle will rotate with respect to the shaft.

2. The wrench of claim 1, wherein the wrench is configured so that if an axial force exceeding a warning threshold is applied to the handle housing, then tactile feedback will be provided to a user, where the warning threshold is less than the first threshold.

3. The wrench of claim 2, wherein the tactile feedback is axial movement of the handle housing with respect to the shaft.

4. The wrench of claim 1, further comprising:

an internal spring cap within the handle housing, wherein the internal spring cap is coupled to the shaft;

a first spring positioned between an end of the handle housing and a first side of the internal spring cap.

5. The wrench of claim 4, wherein the internal spring cap is coupled in a fixed axial position with respect to an end of the shaft.

6. The wrench of claim 4, further comprising:

a first mating structure coupled to the shaft;

a second mating structure coupled to an interior surface of the handle housing,

wherein the first and second mating structures fit together except that when the axial force applied to the handle housing exceeds the first threshold then the first mating structure disengages from the second mating surface allowing the handle housing to rotate with respect to the shaft.

7. The wrench of claim 6, wherein the first mating structure defines at least one tapered notch and the second mating structure comprises at least one protrusion.

8. The wrench of claim 7, wherein the first mating structure defines four tapered notches and the second mating structure comprises four protrusions.

9. The wrench of claim 1, wherein the wrench is configured so that if torque exceeding a second threshold is applied to the handle housing, then the handle housing will rotate with respect to the shaft.

10. A system for coupling a set screw to a medical device comprising:

a header assembly housing, the header assembly housing comprising a dielectric material, the header assembly further defining a set screw receptacle, the header assembly configured to receive a set screw for securing a lead to an electrode;

a set screw comprising a head defining a depression;

a wrench comprising;

a shaft comprising an interface end that is configured to be received in the set screw depression, the shaft defining an axis, and

a handle housing,

wherein the wrench is configured so that if an axial force exceeding a first threshold is applied to the handle housing, then the handle housing will rotate with respect to the shaft.

11. The wrench of claim 10, wherein the wrench is configured so that if an axial force exceeding a warning threshold is applied to the handle housing, then tactile feedback will be provided to a user, where the warning threshold is less than the first threshold.

12. The wrench of claim 10, wherein the tactile feedback is axial movement of the handle housing with respect to the shaft.

13. The system of claim 10, the header assembly housing defining a port aperture for receiving a connector pin of a stimulation lead, the port aperture having a first end and a second end.

14. The system of claim 10, further comprising a pulse generator housing coupled to header assembly housing.

15. The system of claim 10, further comprising:

an internal spring cap within the handle housing, wherein the internal spring cap is coupled to the shaft;

a first spring positioned between an end of the handle housing and a first side of the internal spring cap.

16. The system of claim 15, wherein the internal spring cap is coupled in a fixed axial position with respect to an end of the shaft.

17. The system of claim 16, further comprising:

a first mating structure coupled to the shaft;

a second mating structure coupled to an interior surface of the handle housing,

wherein the first and second mating structures fit together except that when the axial force applied to the handle housing exceeds the first threshold then the first mating structure disengages from the second mating surface allowing the handle housing to rotate with respect to the shaft.

18. The wrench of claim 17, wherein the first mating structure defines four tapered notches and the second mating structure comprises four protrusions.

19. A method for coupling a set screw to a medical device comprising:

providing a set screw comprising a head defining a depression;

providing a wrench comprising;

a shaft comprising an interface end that is configured to be received in the set screw depression, the shaft defining an axis, and

a handle housing,

wherein the wrench is configured so that if an axial force exceeding a first threshold is applied to the handle housing, then the handle housing will rotate with respect to the shaft;

positioning the set screw within an opening in a medical device;

placing the interface end of the wrench in the set screw depression;

rotating the wrench.

20. The method of claim 19, wherein the wrench is configured so that if an axial force exceeding a warning threshold is applied to the handle housing, then tactile feedback will be provided to a user, where the warning threshold is less than the first threshold.