Management of stimulation safety limits in a neurostimulation system

• US 9,440,079 B2
• Filed: 05/13/2012
• Issued: 09/13/2016
• Est. Priority Date: 05/13/2011
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Moffitt, Michael A., Kothandaraman, Sridhar, Peterson, David K. L.
• Primary Examiner(s): Moran, Edward
• Assistant Examiner(s): CAREY, MICHAEL JAMES
• Application Number:
  US13/470,328
• Publication Number:
  US 20120290040A1
• Time in Patent Office: 1,584 Days
• Field of Search: 607/45, 607/59, 607/63
• US Class Current: 1/1
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/37241 providing test stimulations

Abstract

A neurostimulation system for management of stimulation safety limits. The system determines a tissue charge injection metric at each electrode, compares the metric to the hard stop charge limit, and prevents the neurostimulator from delivering stimulation energy to the tissue region in accordance based on the comparison. The hard stop limit may be user-programmable or may be automatically modified in response to detection of electrode characteristics. The system may quantitatively notify a user of a value of the injected charge injected into the tissue. The electrodes may be organized into different sets, in which case, the system may directly control tissue charge independently at each of the electrode sets. If current steering is provided, the system may displace the electrical stimulation energy along the tissue region in one direction, while preventing the charge injection value at each of the electrodes from meeting or exceeding the hard stop charge limit.

Claims

1. A neurostimulation system for concurrent use with a plurality of electrodes, comprising:

a neurostimulator configured for delivering electrical stimulation energy to a tissue region, thereby injecting a charge into the tissue region at each of the electrodes;

memory storing a hard stop charge limit; and

an external control device configured for displacing the electrical stimulation energy along the tissue region in one direction, while preventing a value of the charge injection at each of the electrodes from meeting or exceeding the hard stop charge limit.

2. The neurostimulation system of claim 1, wherein the value of the charge injection is one of a charge density per phase, a k-value, and a charge density per second.

3. The neurostimulation system of claim 1, wherein the value of the charge injection is in terms of one of a relative value, a normalized value, and an absolute value.

4. The neurostimulation system of claim 1, wherein the external control device is configured for displacing the electrical stimulation energy along the tissue region by incrementally shifting electrical current from a first one of the electrodes to a second one of the electrodes, and when the value of the charge injection at the second electrode reaches the hard stop limit, incrementally shifting the electrical current from the first electrode to a third one of the electrodes to continue to displace the electrical stimulation energy along the tissue region in the one direction.

5. The neurostimulation system of claim 1, wherein the external control device is configured for allowing the user to modify the hard stop charge limit.

6. A neurostimulation system for use with at least one electrode, comprising:

a neurostimulator configured for delivering electrical stimulation energy to a tissue region in accordance with a stimulation parameter, thereby injecting a charge into the tissue region at the at least one electrode;

an external control device configured for allowing a user to modify the stimulation parameter;

memory storing a hard stop charge limit; and

control circuitry configured for modifying the hard stop charge limit based on a characteristic of the at least one electrode, determining a tissue charge injection metric at the at least one electrode, comparing the tissue charge injection metric to the modified hard stop charge limit, and preventing the neurostimulator from delivering the electrical stimulation energy to the tissue region in accordance with the modified stimulation parameter based on the comparison, wherein the characteristic of the at least one electrode comprises one of a size, shape, and a material.

8. The neurostimulation system of claim 6, wherein the control circuitry is configured for determining the characteristic of the at least one electrode, and automatically modifying the hard stop charge limit in response to determining the characteristic of the at least one electrode.

7. A neurostimulation system for use with at least one electrode, comprising:

a neurostimulator configured for delivering electrical stimulation energy to a tissue region in accordance with a stimulation parameter, thereby injecting a charge into the tissue region at the at least one electrode;

an external control device configured for allowing a user to modify the stimulation parameter;

memory storing a hard stop charge limit; and

control circuitry configured for modifying the hard stop charge limit based on a characteristic of the at least one electrode, determining a tissue charge injection metric at the at least one electrode, comparing the tissue charge injection metric to the modified hard stop charge limit, and preventing the neurostimulator from delivering the electrical stimulation energy to the tissue region in accordance with the modified stimulation parameter based on the comparison, wherein the at least one electrode is carried by a neurostimulation lead, and the neurostimulation system further comprises monitoring circuitry configured for detecting the type of the neurostimulation lead, and the control circuitry is configured for determining the characteristic of the at least one electrode based on the detected neurostimulation lead type.