Systems and methods for monitoring for nerve damage

Patent metadata

Field	Value
Publication number	US-9855431-B2
Application number	US-201313771964-A
Country	US
Kind code	B2
Filing date	Feb 20, 2013
Priority date	Mar 19, 2012
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

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.

First claim

What is claimed is:

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;
a controller operatively connected to the neural stimulator to control the neural stimulation to deliver a chronic neural stimulation therapy and operatively connected to the sensor to receive a signal indicative of the physiological response; and
an implantable housing containing the neural stimulator and the controller, wherein the controller is configured to automatically perform a process to detect a potential neural injury where the process includes monitoring the sensed physiological response to detect the potential neural injury and performing 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:
automatically control the neural stimulator to modify the chronic neural stimulation therapy in response to the potential neural injury; or
automatically control the neural stimulator to suspend the chronic neural stimulation therapy in response to the potential neural injury; or
automatically initiate a communication signal from the implantable medical device to an external device; or
automatically 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, wherein the controller is configured to monitor the sensed motion to detect the potential neural injury.

3. The device of claim 1 , wherein the controller is configured to perform the process to detect the potential neural injury by performing 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 the controller is configured to perform each of the plurality of neural stimulation threshold tests by:
adjusting an intensity of the neural stimulation across of range of intensity levels;
for each intensity level, monitoring the signal from the sensor to determine if the neural stimulation causes the physiological response sensed by the sensor; and
recording, 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 chronic neural stimulation therapy 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 of the chronic neural stimulation therapy;
or reduce a frequency of the neural stimulation to educe the intensity of the chronic neural stimulation therapy.

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 of the chronic neural stimulation therapy.

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 chronic neural stimulation therapy for a first period of time to allow for nerve recovery from the potential nerve injury, and then reinitiate delivery of the chronic neural stimulation therapy.

13. The device of claim 12 , wherein the controller is configured to:
redetect the potential neural injury after reinitiating delivery of the chronic neural stimulation therapy; and
suspend the chronic neural stimulation therapy 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;
a sensor configured to sense a physiological response to stimulation of motor fibers at the neural target;
a controller operatively connected to the neural stimulator and the sensor; and
an implantable housing containing the neural stimulator and the controller wherein the controller is configured to control the neural stimulation to deliver a chronic neural stimulation therapy and to implement a process 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:
automatically control the neural stimulator to modify the chronic neural stimulation therapy in response to the potential neural injury; or
automatically control the neural stimulator to suspend the chronic neural stimulation therapy in response to the potential neural injury; or
automatically initiate a communication signal from the implantable medical device to an external device; or
automatically store data concerning the detected potential neural injury for later communication.

Assignees

• Cardiac Pacemakers Inc

Inventors

• Ternes David J
• Hamann Jason J
• Ruble Stephen

Classifications

• A61B5/4029

  for evaluating the peripheral nervous systems (using bioelectric or biomagnetic signals A61B5/24) · CPC title

• A61N1/36114

  Cardiac control, e.g. by vagal stimulation (stimulating the heart A61N1/362) · CPC title

• A61N1/36139

  with automatic adjustment · CPC title

• A61B5/686

  Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence) · CPC title

• A61N1/36117

  for treating hypertension · CPC title