System for determining change in position of an implanted medical device within an implant pocket

1 . A system for determining a change in position of an implanted medical device (IMD) within an implant pocket, the system comprising:

an accelerometer configured to be implanted in a patient, the accelerometer configured to obtain accelerometer data along at least one axis;

memory configured to store program instructions;

one or more processors that, when executing the program instructions, are configured to:

determine when the patient is engaging in a determined activity associated with a standing posture;

responsive to the determination, obtain the accelerometer data during an activity period;

identify postures, indicated by the accelerometer data, over the activity period, the postures including a non-standing posture;

determine a duration of one or more posture periods corresponding to the non-standing posture; and

identify a migration of the IMD within the implant pocket based on the duration of the non-standing posture exceeding a duration threshold.

2 . The system of claim 1 , wherein the one or more processors are further configured to:

determine an extent of the migration of the IMD within the implant pocket based on the accelerometer data; and

suspend obtaining the accelerometer data when the extend of the migration exceeds a migration threshold.

3 . The system of claim 2 , wherein the migration threshold is a fifteen degree (15°) rotation.

4 . The system of claim 2 , wherein the one or more processors are further configured to:

recalibrate a reference standing measurement related to a standing posture after suspending the obtaining of the accelerometer data; and

resume obtaining the accelerometer data in response to recalibration of the reference standing measurement.

5 . The system of claim 1 , wherein to recalibrate a reference standing measurement the one or more processors are configured to:

obtain plural readings along an x-axis, y-axis, and z-axis with the accelerometer during the activity period;

determine a standard deviation based on the plural readings; and

update the reference standing measurement based on the standard deviation.

6 . The system of claim 1 , wherein the one or more processors are further configured to: communicate an alert in response to identifying the migration of the IMD within the implant pocket.

7 . The system of claim 1 , wherein the one or more processors are further configured to: automatically recalibrate a reference standing measurement related to a standing posture in response to identifying the migration of the IMD within the implant pocket.

8 . The system of claim 1 , wherein to determine the patient is engaging in the determined activity, the one or more processors are further configured to: determine whether the patient is moving above a speed threshold, or determine physiological characteristics of the patient.

9 . A computer implemented method for determining a change in position of an implanted medical device (IMD) within a patient, the method comprising:

determining when the patient is engaging in a determined activity associated with a standing posture;

responsive to the determining, obtaining accelerometer data during an activity period;

identifying postures, indicated by the accelerometer data, over the activity period, the postures including a non-standing posture;

determining a duration of one or more posture periods corresponding to the non-standing posture; and

identifying a migration of the IMD within the implant pocket based on the duration of the non-standing posture exceeding a duration threshold.

10 . The method of claim 9 , further comprising:

determining an extent of the migration of the IMD within the implant pocket based on the accelerometer data; and

suspending obtaining the accelerometer data when the extent of the migration exceeds a migration threshold.

11 . The method of claim 10 , further comprising:

recalibrating a reference standing measurement related to a standing posture after suspending the obtaining of the accelerometer data; and

resuming obtaining the accelerometer data in response to recalibration of the reference standing measurement.

12 . The method of claim 9 , further comprising, recalibrating the reference standing measurement by:

obtaining plural readings along an x-axis, y-axis, and z-axis with an accelerometer during the activity period;

determining a standard deviation based on the plural readings; and

updating the reference standing measurement based on the standard deviation.

13 . The method of claim 9 , further comprising communicating an alert in response to identifying the migration of the IMD within the implant pocket.

14 . The method of claim 9 , further comprising automatically recalibrating a reference standing measurement related to a standing posture in response to identifying the migration of the IMD within the implant pocket.

15 . The method of claim 14 , wherein automatically recalibrating the reference standing measurement includes obtaining a long term average of x-axis, y-axis, and z-axis vector data from one or more previous activity periods.

16 . The method of claim 9 , wherein determining the patient is engaging in the determined activity comprises determining whether the patient is moving above a speed threshold.

17 . The method of claim 9 , wherein determining the patient is engaging in the determined activity comprises determining physiological characteristics of the patient.

18 . The system of claim 1 , wherein, during the activity period and while the patient maintains the standing posture, the accelerometer data indicates the non-standing posture due to the migration of the IMD within the implant pocket.

19 . The system of claim 1 , wherein the one or more processors are further configured to calculate, over at least a portion of the determined activity, at least one of an extent of right (ETR) or extent of supine (ETS) parameter based on the accelerometer data, the migration identified in part based on at least one of the ETR or ETS parameter.

20 . The system of claim 1 , wherein the at least one of the ETR or ETS provides a degree tilt, flip, rotation or angle of an orientation of the IMD with respect to a standing posture, the migration identified in part based on an expected ETR or ETS value when the patient is in the engaged in the determined activity.

21 . The method of claim 9 , wherein, during the activity period and while the patient maintains the standing posture, the accelerometer data indicates the non-standing posture due to the migration of the IMD within the implant pocket.