ALTERNATIVE OPERATION MODE FOR AN IMPLANTABLE MEDICAL DEVICE BASED UPON LEAD CONDITION

• US 20090125079A1
• Filed: 10/26/2007
• Published: 05/14/2009
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: Maschino, Steven E., Armstrong, Randolph K., Rodriguez, Albert A.
• Granted Patent: US 8,942,798 B2
• Time in Patent Office: Days
• US Class Current: 607/45
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0558 Anchoring or fixation means therefor
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease

Abstract

The present invention provides for a method, apparatus, and system for determining an adverse operational condition associated with a lead assembly in an implantable medical device used for providing a therapeutic electrical signal to a cranial nerve. A first impedance associated with the lead assembly configured to provide the therapeutic electrical signal to a cranial nerve is detected. A determination is made as to whether the first impedance is outside a first predetermined range of values. A second impedance is detected. The detection of the second impedance is performed within a predetermined period of time from the time of the detection of the first impedance. A determination is made as to whether the second impedance is outside a second predetermined range of values. A determination that a lead condition problem exists is made in response to a determination that the first is outside the first predetermined range of values and second impedance is outside the second predetermined range of values. The implantable medical device is prevented from providing the therapeutic electrical signal to the cranial nerve in response to determining that the lead condition problem exists.

Claims

1. A method for determining an adverse operational condition associated with a lead assembly in an implantable medical device used for providing a therapeutic electrical signal to a cranial nerve, said method comprising:

detecting a first impedance associated with said lead assembly configured to provide said therapeutic electrical signal to a cranial nerve;

determining whether said first impedance is outside a first predetermined range of values;

detecting a second impedance, the detection of said second impedance being performed within a predetermined period of time from the time of the detection of said first impedance;

determining whether said second impedance is outside a second predetermined range of values;

determining that a lead condition problem exists in response to a determination that said first is outside said first predetermined range of values and second impedance is outside said second predetermined range of values; and

preventing said implantable medical device from providing said therapeutic electrical signal to said cranial nerve in response to determining that said lead condition problem exists.

2. The method of claim 1, wherein said detecting said first and second lead impedances comprises:

providing a controlled current signal through a first terminal and a second terminal associated with said lead assembly;

measuring a voltage across said first and second terminals during at least a portion of a time period during which said controlled current is provided through said first and second terminals; and

determining the impedance across said first and second terminals based upon said constant current signal and said measured voltage.

3. The method of claim 2, further comprising detecting an operational parameter associated with an operation performed by said implantable medical device, wherein said operational parameter is selected from the group consisting of a current parameter, a power output parameter, an energy output parameter, a charge delivered per pulse parameter;

a charge imbalance parameter, and a compensation voltage parameter.

4. The method of claim 3, further comprising determining that a lead condition problem exists based upon the value of said operational parameter and at least one of said first impedance or said second impedance.

5. The method of claim 1, wherein determining that a lead condition problem exists further comprises determining whether said problem is a significant problem or not a significant problem, and wherein said terminating the operation of said implantable medical device is performed in response to a determination that said lead condition problem is a significant problem.

6. The method of claim 5, wherein said implantable medical device enters a secondary mode of operation from a normal mode of operation upon determining that said lead condition problem is not a significant lead condition problem.

7. The method of claim 6, wherein entering said secondary operation mode comprises performing at least one action selected from the group consisting of:

performing a pre-stimulation diagnostic check prior to delivering a therapeutic electrical signal from said implantable medical device to a portion of a patient'"'"'s body;

shutting down an operation of said IMD;

modifying an electrical parameter defining said therapeutic electrical signal;

or

disabling an electrode associated with said lead assembly.

8. The method of claim 7, wherein performing a pre-stimulation diagnostic check comprises determining whether said lead condition problem is an intermittent problem.

9. The method of claim 1, further comprising performing a notification process in response to said determination that a lead condition problem exists.

10. The method of claim 8, wherein said notification process comprises performing at least one of a patient notification process, a health-care professional notification process, and a manufacturer notification process.

11. The method of claim 9, wherein said patient notification process comprises at least one of an audible notification, a tactile notification, a vibration notification, an electrical notification, or an electronic notification.

12. A method for determining a status assessment of a lead assembly in an implantable medical device for providing a therapeutic electrical signal to a cranial nerve, said method comprising:

performing a first test to determine if a first indication of a lead break is present;

performing a first remedial action based upon a determination that said first indication of a lead break is present;

performing a second test to determine if a second indication of a lead break is present, wherein said second indication of the lead break indicates a significant lead break; and

performing a second remedial action based upon a determination that said second indication of a lead break is present, wherein said second remedial action comprises preventing said implantable medical device from applying said therapeutic electrical signal to said cranial nerve.

13. The method of claim 12, wherein performing said first test comprises performing a lead impedance test upon said lead assembly.

14. The method of claim 12, wherein performing said first remedial action comprises an action selected from the group consisting modifying at least one electrical parameter defining a therapeutic electrical signal provided to a target body tissue by said implantable medical device, performing a pre-stimulation diagnostic check prior to delivering a therapeutic electrical signal from said implantable medical device, to a portion of a patient'"'"'s body, and disabling an electrode associated with said lead assembly;

wherein performing said second remedial action comprises terminating an operation of said implantable medical device.

15. The method of claim 14, wherein performing said second test comprises performing a diagnostic test, wherein said diagnostic test comprises performing at least one of a current output test, a lead impedance test, a power output test, an energy output test, a charge imbalance test, and a compensation voltage test.

16. An implantable medical device for determining an adverse operational condition associated with a lead assembly coupled to the implantable medical device, comprising:

a stimulation unit to provide a therapeutic electrical signal to a cranial nerve, through a lead operatively coupled to said IMD;

an impedance detection unit to provide a first impedance data and a second impedance data; and

a controller operatively coupled to said stimulation unit and said impedance detection unit, said controller to determine that a significant lead condition problem is present in response to a determination that said first and second impedance data are outside a predetermined range of values, said controller to prevent said stimulation unit from providing said therapeutic electrical signal to said cranial nerve in response to said determination that said significant lead condition problem is present.

17. The implantable medical device of claim 16, wherein said significant lead condition problem is at least one of a lead break or an electrical short relating to a terminal associated with said lead.

18. The implantable medical device of claim 16, further comprising:

a diagnostic unit for performing at least one diagnostic procedure relating to said implantable medical device to generate diagnostic data;

a lead condition detection unit capable of performing a statistical analysis using said diagnostic data to generate lead condition data; and

a therapy mode control unit to control the type of therapeutic electrical signal generated by said stimulation unit based upon said lead condition data.

19. The implantable medical device of claim 16, wherein said lead condition detection unit is capable of detecting whether said lead condition relates to an intermittent lead problem.

20. A method for determining a condition associated with a lead assembly in an implantable medical device for providing a therapeutic electrical signal to a cranial nerve, said method comprising:

monitoring the lead condition of said lead assembly;

receiving data relating to said lead condition;

performing a lead condition analysis to determine whether a lead problem is present;

determining whether said lead condition is a significant lead condition;

preventing said implantable medical device from providing said therapeutic electrical signal to said cranial nerve upon a determination that said lead condition is a significant lead condition; and

implementing a secondary operation mode of said implantable medical device in response to a determination that said lead condition is not a significant lead condition.

22. The method of claim 20, wherein said lead condition analysis comprises:

detecting a lead impedance;

determining whether said impedance is outside a predetermined range;

performing a diagnostic function in response to a determination that said impedance is outside a predetermined range, to generate diagnostic data; and

perform a statistical analysis using said diagnostic data to determine whether a lead condition problem has occurred.

23. The method of claim 20, further comprising:

performing a diagnostic function to generate diagnostic data;

determining whether at least one operational parameter relating to an operation of said implantable medical device is out of a predetermined tolerance level, said operational parameter comprising at least one parameter selected from the group consisting of battery consumption, high current indication, low current indication, power output, energy output, and charge delivered per pulse;

detecting an impedance associated with said lead assembly;

determining whether said impedance is outside a range of predetermined tolerance; and

reporting a lead problem based upon said determination that said operation parameter and said impedance is outside said range of predetermined tolerance level.

24. The method of claim 20, wherein implementing said secondary operation mode of said implantable medical device comprises:

generating an indication to operate in said secondary operation mode;

determining whether said lead problem is an intermittent problem;

performing a pre-stimulation check regimen prior to providing an electrical signal;

implementing an operation mode, said operation mode comprises at least one of a ceasing to provide said therapeutic electrical signal to said cranial nerve, delivering an alternative dosage of a therapeutic electrical signal to said cranial nerve, or disabling a faulty electrode.

21. The method of claim 21, further comprising performing a notification function in response to determining that a lead problem is present, said notification process comprises notifying of said lead problem to at least one of a patient, a health-care professional, a manufacturer of at least a portion of said implantable medical device, or a manufacturer of at least a portion of said lead assembly.