Atraumatic sensor lead assemblies

• US 20040087847A1
• Filed: 10/31/2002
• Published: 05/06/2004
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Sommer, John L., Christopherson, Mark A., Pool, Nancy Perry, Bonde, Eric
• Granted Patent: US 7,087,017 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems

Abstract

The invention is directed to lead configurations for sensors that allow for less invasive sensor replacement procedures. In one configuration, a sensor lead assembly includes an outer lead body and an inner lead including a sensor such as an electrochemical glucose sensor. The inner lead can be positioned in an inner conduit of the outer lead body. The outer lead body may be substantially permanently implanted in the patient, and the inner lead can be implanted through the inner conduit of the outer lead body. Once the sensor of the inner lead has worn out or otherwise exhausted its useful life, the inner lead can be removed, and a new inner lead can be implanted in place of the old inner lead.

Claims

1. A sensor lead assembly comprising:

an outer lead body for implantation in a patient, the outer lead body defining a first end, a second end and a conduit between the first and second ends, the first end being formed for mechanical attachment to a housing of an implantable medical device; and

an inner lead positioned in the conduit of the outer lead body, the inner lead including an sensor positioned in proximity to a distal end of the inner lead.

2. The sensor lead assembly of claim 1, wherein the sensor comprises an electrochemical sensor.

3. The sensor lead assembly of claim 2, wherein the second end is formed with a seal pierced by the inner lead.

4. The sensor lead assembly of claim 3, wherein the seal defines a plurality of redundant sealing structures each pierced by the inner lead.

5. The sensor lead assembly of claim 1, wherein the outer lead body defines a substantially rigid layer to avoid collapse of the outer lead body in response to a suture tied around the outer lead body during an implant procedure.

6. The sensor lead assembly of claim 1, wherein the conduit of the outer lead body is formed to removably receive the inner lead, and wherein the inner lead is formed for removable insertion into the conduit.

7. The sensor lead assembly of claim 1, wherein the outer lead body is formed with a window in proximity to a distal end of the outer lead body, wherein the inner lead is formed with a plurality of sensors formed along axial positions of the inner lead in proximity to a distal end of the inner lead.

8. The sensor lead assembly of claim 7, wherein the inner lead is axially repositionable relative to the window of the outer lead body to selectively expose different sensors.

9. The sensor lead assembly of claim 1, wherein the sensor comprises an electrochemical glucose sensor.

10. The electrochemical lead assembly of claim 1, wherein the outer lead body includes a metal portion in proximity to a distal end of the outer lead body.

22. The implantable medical device of claim 10, wherein the sensor comprises an electrochemical glucose sensor.

23. The implantable medical device of claim 10, wherein the outer lead body includes a radio opaque portion in proximity to a distal end of the outer lead body to facilitate positioning of the inner lead relative to the outer lead body during an implant procedure.

11. An implantable medical device comprising:

a housing including circuitry for storing sensed conditions;

an outer lead body mechanically coupled to the housing, the outer lead body defining a conduit; and

an inner lead positioned in the conduit of the outer lead body and electrically coupled to the circuitry at a first end of the inner lead, the inner lead including a sensor positioned in proximity to a second end of the inner lead.

12. The implantable medical device of claim 11, wherein the housing further includes circuitry for interpreting sensed conditions.

13. The implantable medical device of claim 11, wherein the outer lead body defines a first end and a second end, wherein the first end of the outer lead body is formed for mechanical attachment to the implantable medical device.

14. The implantable medical device of claim 13, wherein the second end of the outer lead body is formed with a seal pierced by the inner lead.

15. The implantable medical device of claim 14, wherein the seal defines a plurality of redundant sealing structures each pierced by the inner lead.

16. The implantable medical device of claim 11, wherein the outer lead body defines a substantially rigid layer to avoid collapse of the outer lead body in response to a suture tied around the outer lead body during an implant procedure.

17. The implantable medical device of claim 11, wherein the conduit of the outer lead body is formed to removably receive the inner lead, and wherein the inner lead is formed for removable insertion into the conduit.

18. The implantable medical device of claim 11, wherein the outer lead body is formed with a window in proximity to a distal end of the outer lead body, wherein the inner lead is formed with a plurality of sensors formed along axial positions of the inner lead in proximity to the second end of the inner lead.

19. The implantable medical device of claim 18, wherein the inner lead can be repositioned relative to the window of the outer lead body to expose different sensors.

20. The implantable medical device of claim 18, wherein the inner lead includes an electrical contact that electrically couples to circuitry in the housing, wherein each of the sensors is electrically coupled to the circuitry via the electrical contact.

21. The implantable medical device of claim 20, wherein the electrical contact comprises a plurality of electrical contact areas formed along axial positions of the inner lead, wherein each of the sensors electrically couples to the circuitry via a corresponding one or more of the electrical contact areas.

24. An outer lead body for substantially permanent implantation in a patent comprising:

a first end formed for mechanical attachment to an implantable medical device;

a second end formed with a seal to be pierced by an inner lead; and

a conduit formed in the outer lead body between the first and second end for receiving the inner lead, wherein the seal defines a plurality of redundant sealing structures to be pierced by the inner lead.

25. The outer lead body of claim 24, wherein the outer lead body defines a substantially rigid layer in at least a section of the outer lead body to avoid collapse of the outer lead body in response to a suture tied around the outer lead body during an implant procedure.

26. The outer lead body of claim 24, wherein the conduit is formed to removably receive an inner lead, the inner lead including an electrochemical sensor.

27. The outer lead body of claim 24, wherein the outer lead body is formed with a window in proximity to a distal end.

28. The outer lead body of claim 24, wherein the outer lead body includes a metal portion in proximity to the second end to facilitate positioning of an inner lead relative to the outer lead body during an implant procedure.

29. A lead comprising:

a lead body defining a first end and a second end; and

a plurality of electrochemical sensors formed along axial positions of the lead body in proximity to the second end; and

an electrical contact formed on the lead body in proximity to the first end, wherein each of the electrochemical sensors is electrically coupled to the electrical contact.

30. The lead of claim 29, wherein the electrical contact defines a plurality of electrical contact areas formed along axial positions of the lead body in proximity to the second end, wherein each of the electrochemical sensors is electrically coupled to a corresponding one of the plurality of electrical contact areas.

31. A method comprising:

removing a first lead including a first sensor from an implanted outer lead body; and

inserting a second lead including a second sensor into the implanted outer lead body.

32. The method of claim 31, further comprising removing the first lead through a channel of a connector module of an implantable medical device.

33. The method of claim 31, further comprising:

unattaching the outer lead body from a housing of an implantable medical device prior to removing the first lead; and

reattaching the outer lead body to the housing of the implantable medical device following insertion of the second lead.

34. The method of claim 31, further comprising flushing the outer lead body with a solution to clean the outer lead body following removal of the first lead and prior to insertion of the second lead.

35. A method comprising:

positioning an inner lead relative to a window of an outer lead body to expose a first sensor; and

repositioning the inner lead relative to the window of the outer lead body to expose a second sensor.

36. The method of claim 35, further comprising detecting failure of the first sensor prior to repositioning the inner lead relate to the window of the outer lead body to expose a second sensor.

37. The method of claim 35, wherein the method is performed by an implantable medical device.

38. The method of claim 37, further comprising programming the implantable medical device to execute the method.

39. A glucose monitoring lead assembly comprising:

an outer lead body for substantially permanent implantation in a patient, the outer lead body being formed with a conduit; and

an inner lead positioned in the conduit of the outer lead body, the inner lead including a glucose sensor positioned in proximity to a distal end of the inner lead.

40. A electrochemical lead assembly comprising:

an outer lead body for implantation in a patient, the outer lead body defining a conduit; and

an inner lead positioned in the conduit of the outer lead body, the inner lead including an electrochemical sensor positioned in proximity to a distal end of the inner lead.