Apparatus and methods for detecting position and migration of neurostimulation leads

• US 20060224187A1
• Filed: 04/01/2005
• Published: 10/05/2006
• Est. Priority Date: 04/01/2005
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Kapoor, Sunil K., Bradley, Kerry
• Granted Patent: US 8,401,665 B2
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/3614 based on impedance measurement
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/37241 providing test stimulations

Abstract

Apparatus and methods for detecting lead migration through the use of measured artifactual data about the tissue in the vicinity of the lead.

Claims

1. A method to determine whether a neurostimulation lead has migrated, comprising:

measuring the impedance of tissue in the vicinity of an electrode on the neurostimulation lead to establish a baseline impedance value;

measuring the impedance of the tissue in the vicinity of the electrode at a subsequent time to establish a subsequent impedance value; and

determining whether the neurostimulation lead has migrated by comparing the subsequent impedance value to the baseline impedance value.

2. A method as claimed in claim 1, wherein

the neurostimulation lead includes a plurality of electrodes;

measuring the impedance of tissue to establish a baseline impedance value comprises measuring the impedance of the tissue in the vicinity of multiple electrodes to establish respective baseline impedance values;

measuring the impedance of the tissue to establish a subsequent impedance value comprises measuring the impedance of the tissue in the vicinity of each of the multiple electrodes at a subsequent time to establish respective subsequent impedance values; and

determining whether the neurostimulation lead has migrated comprises comparing the subsequent impedance values to the baseline impedance values.

3. A method as claimed in claim 2, wherein determining whether the neurostimulation lead has migrated further comprises determining the direction and magnitude of the migration.

4. A method as claimed in claim 3, wherein determining the direction and magnitude of the migration comprises performing a feature comparison analysis.

5. A method as claimed in claim 1, wherein measuring the impedance of tissue in the vicinity of an electrode comprises sourcing current into tissue at an implantable pulse generator and sinking the current at the electrode.

6. A method as claimed in claim 1, wherein measuring the impedance of tissue in the vicinity of an electrode comprises sourcing current into tissue at an implantable pulse generator and sinking the current at the electrode in between therapeutic pulses supplied by the implantable pulse generator to the electrode.

7. A method as claimed in claim 1, further comprising:

taking corrective action in response to a determination that the neurostimulation lead has migrated.

8. A method as claimed in claim 7, wherein taking corrective action comprises reprogramming a therapeutic regimen in response to a determination that the neurostimulation lead has migrated.

9. A neurostimulation system for use with an implantable lead including at least one lead electrode, the neurostimulation system comprising:

a pulse generator including a lead connector;

circuitry, operably connected to the lead connector, to measure the impedance of tissue in the vicinity of the at least one lead electrode to establish a baseline impedance value and measure the impedance of the tissue in the vicinity of the at least one lead electrode at a subsequent time to establish a subsequent impedance value; and

circuitry to determine whether the implantable lead has migrated by comparing the subsequent impedance value to the baseline impedance value.

10. A neurostimulation system as claimed in claim 9, wherein

the at least one lead electrode comprises a plurality of lead electrodes;

the circuitry to measure comprises circuitry to measure the impedance of the tissue in the vicinity of multiple lead electrodes to establish respective baseline impedance values and to measure the impedance of the tissue in the vicinity of each of the multiple lead electrodes at a subsequent time to establish subsequent impedance values; and

the circuitry to determine comprises circuitry to determine whether the implantable lead has migrated by comparing the subsequent impedance values to the baseline impedance values.

11. A neurostimulation system as claimed in claim 9, wherein the circuitry to determine comprises circuitry to determine the direction and magnitude of the migration.

12. A neurostimulation system as claimed in claim 9, further comprising:

an electrode associated with the pulse generator;

wherein the circuitry to measure comprises circuitry to source current into tissue at the electrode associated with the pulse generator and sink the current at the at least one lead electrode.

13. A neurostimulation system as claimed in claim 12, wherein the electrode associated with the pulse generator comprises a pulse generator case.

14. A neurostimulation system as claimed in claim 9, wherein the pulse generator comprises an implantable pulse generator and the circuitry to determine is located within the implantable pulse generator.

15. A neurostimulation system as claimed in claim 9, further comprising:

at least one external device that communicates with the implantable pulse generator;

wherein the circuitry to determine is located in the at least one external device.

16. A neurostimulation system as claimed in claim 9, further comprising:

circuitry to supply therapeutic pulses in accordance with a programmed therapeutic regimen and to adjust the programmed therapeutic regimen in response to a determination that the implantable lead has migrated.

17. A neurostimulation system as claimed in claim 16, wherein the at least one lead electrode comprises a plurality of lead electrodes, the neurostimulation system further comprising:

circuitry to adjust which of the plurality of lead electrodes receives therapeutic pulses in response to a determination that the implantable lead has migrated.

18. A method to determine the relative position of first and second neurostimulation leads, comprising:

measuring the impedance of tissue between the first neurostimulation lead and an electrode located in spaced relation to the first and second neurostimulation leads;

measuring the impedance of tissue between the second neurostimulation lead and the electrode located in spaced relation to the first and second neurostimulation leads; and

comparing the impedance measurements.

19. A method as claimed in claim 18, wherein

measuring the impedance of tissue between the first neurostimulation lead and an electrode comprises measuring the impedance of tissue between the first neurostimulation lead and an electrode associated with an implantable pulse generator located in spaced relation to the first and second neurostimulation leads;

and

measuring the impedance of tissue between the second neurostimulation lead and the electrode comprises measuring the impedance of tissue between the second neurostimulation lead and the electrode associated with the implantable pulse generator located in spaced relation to the first and second neurostimulation leads.

20. A method as claimed in claim 18, wherein

measuring the impedance of tissue between the first neurostimulation lead and an electrode comprises individually measuring the impedance of tissue between a plurality of electrodes on the first neurostimulation lead and an electrode located in spaced relation to the first and second neurostimulation leads;

and

measuring the impedance of tissue between the second neurostimulation lead and the electrode comprises individually measuring the impedance of tissue between a plurality of electrodes on the second neurostimulation lead and the electrode in spaced relation to the first and second neurostimulation leads.

21. A method as claimed in claim 20, wherein

comparing the impedance measurements comprises comparing an average of the impedances between the plurality of electrodes on the first neurostimulation lead and the electrode located in spaced relation to the first and second neurostimulation leads to an average of the impedances between the plurality of electrodes on the second neurostimulation lead and the electrode located in spaced relation to the first and second neurostimulation leads.