SYSTEMS AND METHODS FOR MONITORING FOR NERVE DAMAGE

• US 20130245722A1
• Filed: 02/20/2013
• Published: 09/19/2013
• Est. Priority Date: 03/19/2012
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Ternes, David J., Hamann, Jason J., Ruble, Stephen
• Granted Patent: US 9,855,431 B2
• Time in Patent Office: Days
• US Class Current: 607/62
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/395 Details of stimulation, e.g. nerve stimulation to elicit EMG response
• CPC Class Codes: A61B 5/4029 for evaluating the peripheral nervous systems A61B5/24 takes precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36117 for treating hypertension
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators

Abstract

Various device embodiments may comprise an implantable medical device for implantation in a body and for applying neural stimulation to a neural target in the body. The device may comprise a neural stimulation electrode configured for use in stimulating the neural target, a neural stimulator configured to deliver neural stimulation through the electrode to the neural target, a sensor configured to sense a physiological response to stimulation of motor fibers at the neural target, and a controller operatively connected to the neural stimulator to control the neural stimulation and operatively connected to the sensor to receive a signal indicative of the physiological response. The controller may be configured to detect a potential neural injury and perform an action in response to the detected potential neural injury.

Claims

1. An implantable medical device for implantation in a body and for applying neural stimulation to a neural target in the body, the device comprising:

a neural stimulation electrode configured for use in stimulating the neural target;

a neural stimulator configured to deliver neural stimulation through the electrode to the neural target;

a sensor configured to sense a physiological response to stimulation of motor fibers at the neural target; and

a controller operatively connected to the neural stimulator to control the neural stimulation and operatively connected to the sensor to receive a signal indicative of the physiological response, wherein the controller is configured to detect a potential neural injury and perform an action in response to the detected potential neural injury, wherein in performing the action in response to the detected potential neural injury, the controller is configured to;

control the neural stimulator to modify the neural stimulation in response to the potential neural injury;

or

control the neural stimulator to suspend the neural stimulation in response to the potential neural injury;

or

initiate a communication signal to an external device;

or

store data concerning the detected potential neural injury for later communication.

2. The device of claim 1, wherein the sensor includes an accelerometer configured to sense motion caused by stimulation of motor fibers at the neural target.

3. The device of claim 1, wherein in detecting the potential neural injury, the controller is configured to perform a plurality of neural stimulation threshold tests to monitor for drift in a stimulation threshold stimulating the motor fibers.

4. The device of claim 3, wherein in performing each of the plurality of neural stimulation threshold tests, the controller is configured to:

adjust an intensity of the neural stimulation across of range of intensity levels;

for each intensity level, monitor the signal from the sensor to determine if the neural stimulation causes the physiological response sensed by the sensor; and

record, as the neural stimulation threshold, a lowest intensity level for the neural stimulation that causes the motion sensed by the sensor.

5. The device of claim 3, wherein the controller is configured to:

monitor for acute and chronic changes in the neural stimulation threshold;

use a first threshold to monitor for acute changes; and

use a second threshold to monitor for chronic changes.

6. The device of claim 3, wherein the controller is configured to initiate the neural stimulation threshold tests.

7. The device of claim 3, wherein the device includes a programmed schedule, and the controller is configured to initiate the neural stimulation threshold tests according to the programmed schedule.

8. The device of claim 1, wherein the controller is configured to reduce an intensity of the neural stimulation in response to the potential neural injury.

9. The device of claim 8, wherein the controller is configured to:

reduce an amplitude of the neural stimulation to reduce the intensity;

or

reduce a frequency of the neural stimulation to reduce the intensity.

10. The device of claim 8, wherein the controller is configured to:

deliver intermittent neural stimulation with alternating stimulation ON and stimulation OFF times,

deliver a train of neural stimulation pulses during the stimulation ON times; and

reduce a duration of the stimulation ON time to reduce the intensity.

11. The device of claim 1, further comprising additional neural stimulation electrodes configured to provide more than one electrode configuration for stimulating the neural target, wherein the controller is configured to stimulate the neural target using a first electrode configuration, and configured to stimulate the neural target using a second electrode configuration in response to the potential neural injury.

12. The device of claim 1, wherein the controller is configured to suspend the neural stimulation for a first period of time to allow for nerve recovery from the potential nerve injury, and then reinitiate delivery of the neural stimulation.

13. The device of claim 12, wherein the controller is configured to:

redetect the potential neural injury after reinitiating delivery of the neural stimulation; and

suspend the neural stimulation for a second period of time greater than the first period of time if the potential neural injury is redetected to provide more time for nerve recovery.

14. The device of claim 1, wherein the neural target includes a vagus nerve in a cervical region of the body, and the sensor is configured to detect laryngeal vibration caused by stimulation of motor fibers in the vagus nerve.

15. The device of claim 1, wherein the neural target includes a nerve selected from the group of nerves consisting of:

a sciatic nerve, a peroneal nerve, a hypoglossal nerve and a spinal motor nerve.

16. The device of claim 1, wherein the controller is configured to check for a device problem to determine if the detected potential injury is likely the device problem rather than an actual neural injury, the controller is configured to check for the device problem in response to the detected potential neural injury before performing the action, and wherein in checking for the device problem, the controller is configured to check lead impedance.

17. An implantable medical device for implantation in a body and for applying neural stimulation to a neural target in the body, the device comprising:

a neural stimulation electrode configured for use in stimulating the neural target;

a neural stimulator configured to deliver neural stimulation through the electrode to the neural target; and

a controller operatively connected to the neural stimulator to control the neural stimulation and configured to communicate with an external motion sensor to receive a signal indicative of sensed motion caused by stimulation of motor fibers at the neural target, wherein the controller is configured to detect a potential neural injury and perform an action in response to the detected neural injury, and wherein in performing the action in response to the detected neural injury the controller is configured to;

control the neural stimulator to modify the neural stimulation in response to the potential neural injury;

or

control the neural stimulator to suspend the neural stimulation in response to the potential neural injury;

or

initiate a communication signal to an external device;

or

store data concerning the detected potential neural injury for later communication.

18. A system for delivering vagal nerve stimulation to a vagus nerve within a cervical region of a body, the system comprising;

an implantable neural stimulation electrode configured to deliver neural stimulation to the vagus nerve in the cervical region;

an implantable neural stimulator configured to deliver the vagal nerve stimulation through the electrode to the vagus nerve;

an implantable controller operably connected to the neural stimulator to control delivery of the vagal nerve stimulation; and

an accelerometer configured to sense motion from laryngeal vibration caused by stimulation of motor fibers in the vagus nerve,

wherein the controller is configured to receive a signal indicative of the sensed motion from the accelerometer,

wherein the controller is configured to detect a potential neural injury to the vagus nerve and perform an action in response to the detected neural injury,

wherein in detecting the potential neural injury, the controller is configured to perform a plurality of neural stimulation threshold tests to monitor for drift in a stimulation threshold that causes the motion sensed by the accelerometer, and

wherein in performing the action in response to the detected neural injury the controller is configured to;

control the neural stimulator to modify the neural stimulation in response to the potential neural injury;

or

control the neural stimulator to suspend the neural stimulation in response to the potential neural injury;

or

initiate a communication signal to an external device or store data concerning the detected potential neural injury for later communication.

19. A method, comprising:

using an implantable medical device to deliver a neural stimulation therapy to a neural target;

detecting a potential neural injury, wherein detecting the potential neural injury includes sensing motion caused by stimulation of motor fibers at the neural target and detecting a drift in a stimulation threshold that causes the sensed motion; and

using the implantable medical device to perform an action as a programmed response to the detected neural injury, wherein using the implantable medical device to perform the action as the programmed response to the detected neural injury includes;

modifying the neural stimulation in response to the potential neural injury;

Or

suspending the neural stimulation in response to the potential neural injury;

or

initiating a communication signal to an external device;

or

storing data concerning the detected potential neural injury for later communication.

20. A method, comprising:

using an implantable medical device to deliver a vagal nerve stimulation therapy to a cervical vagus nerve;

detecting a potential neural injury, wherein detecting the potential neural injury includes sensing laryngeal vibration caused by stimulation of motor fibers of the cervical vagus nerve and detecting a drift in a stimulation threshold that causes the sensed laryngeal vibration; and

using the implantable medical device to perform an action as a programmed response to the detected neural injury, wherein using the implantable medical device to perform the action as the programmed response to the detected neural injury includes;

modifying the neural stimulation in response to the potential neural injury;

Or

suspending the neural stimulation in response to the potential neural injury;

or

initiating a communication signal to an external device;

or

storing data concerning the detected potential neural injury for later communication.