SEPTUM PORT LOCATOR SYSTEM AND METHOD FOR AN IMPLANTABLE THERAPEUTIC SUBSTANCE DELIVERY DEVICE

• US 20080281279A1
• Filed: 05/11/2007
• Published: 11/13/2008
• Est. Priority Date: 05/11/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Sarkinen, Scott A., Kalpin, Scott L., Hoendervoogt, Jason J.
• Granted Patent: US 7,806,122 B2
• Time in Patent Office: Days
• US Class Current: 604/288.01
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61M 2209/045 for filling, e.g. for filling reservoirs
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/427 Locating point where body is to be pierced, e.g. vein location means using ultrasonic waves, injection site templates

Abstract

An implantable medical device system includes an implantable device and an external locator device for percutaneously locating detecting port opening of the implantable device. The implantable device includes a port chamber forming the port opening, a septum sealing the port chamber relative to an exterior of the device, and a coil positioned at a known location relative to the port opening. The locator device includes a controller, at least one X-loop electrically coupled to the controller and oriented along a first major axis, and at least one Y-loop electrically coupled to the controller and oriented along a second major axis differing from the first major axis. The system is configured such that when the locator is spatially proximate the coil, an induced voltage in at least the Y-loop(s) is read by the controller to indicate a location of the coil relative to the locator device.

Claims

1. An implantable medical device system comprising:

an implantable substance delivery device including;

a housing maintaining a reservoir for containing a therapeutic substance,

a fill port assembly defining a port chamber having a fill port opening and in fluid communication with the reservoir,

a first coil positioned at a known location relative to the fill port opening; and

an external locator device for detecting the coil, the device including;

a controller,

a locator grid including;

at least one X-loop electrically coupled to the controller and oriented along a first major axis,

at least one Y-loop electrically coupled to the controller and oriented along a second major axis differing from the first major axis;

wherein the system is configured such that when the locator grid is spatially proximate the coil, energization of the coil induces a voltage in the at least one Y-loop that is read by the controller, and further wherein the controller is adapted to determine a location of the coil relative to the locator grid based upon the read voltage.

2. The system of claim 1, wherein the first coil is co-axially centered relative to the fill port opening.

3. The system of claim 1, wherein the first coil is off-set from the fill port opening.

4. The system of claim 1, wherein the implantable substance delivery device includes a plurality of coils each of which is off-set from the fill port opening at a known location, and further wherein the controller is adapted to locate a position of the fill port opening based upon determined locations of the plurality of coils.

5. The system of claim 1, wherein the implantable substance delivery device further includes:

a second coil positioned at a known location relative to the fill port opening;

a first capacitor coupled to the first coil to form a first circuit; and

a second capacitor coupled to the second coil to form a second circuit.

6. The system of claim 5, wherein the controller is adapted to energize the X-loop at a first frequency corresponding with a known, first frequency of the first circuit in locating the first coil, and at a second frequency corresponding with a known, second frequency of the second circuit in locating the second coil.

7. The system of claim 1, wherein the at least one X-loop comprises a central X-loop oriented along a first central axis and the at least one Y-loop comprises a central Y-loop oriented along a second central axis, and further wherein the locator device defines a needle opening extending through the locator device at a location where the first central axis intersects the second central axis.

8. The system of claim 1, wherein the second major axis is orthogonal to the first major axis.

9. The system of claim 1, wherein the locator grid includes a plurality of X-loops, each X-loop including a major axis that is parallel to the first major axis such that each X-loop is staggered relative to a neighboring X-loop.

10. The system of claim 1, wherein the locator grid includes a plurality of Y-loops, each Y-loop including a major axis that is parallel to the second major axis such that each Y-loop is staggered relative to a neighboring Y-loop.

11. The system of claim 10, wherein the locator grid further includes a plurality of X-loops interleaved with the plurality of Y-loops.

12. The system of claim 11, wherein the plurality of X-loops are electrically decoupled from the plurality of Y-loops.

13. The system of claim 1, wherein the at least one X-loop comprises a rectangular loop defining a first side opposite a second side and opposing ends, the first and second sides parallel to the first major axis and the opposing ends parallel to a minor axis of the X-loop that is substantially orthogonal to the first major axis.

14. The system of claim 1, wherein the locator device includes a locator power source and the coil is a passive coil characterized by an absence of a direct power source coupled thereto.

15. The system of claim 14, wherein the system is adapted such that when the locator grid is positioned proximate the coil and a current is applied to the X-loop, the coil is energized and a voltage is induced in the Y-loop.

16. The system of claim 1, wherein the implantable substance delivery device further includes a power source coupled to the coil.

17. The system of claim 16, wherein the system is adapted such that when the locator grid is positioned proximate the coil and the coil is energized by the power source, a voltage is induced in the X-loop and in the Y-loop.

18. The system of claim 1, wherein the locator grid includes a plurality of X-loops interleaved with a plurality of Y-loops, and further wherein the controller is adapted to iteratively sample and compare signals generated at each of the Y-loops in at least partially determining a location of the coil relative to the locator grid.

19. The system of claim 18, wherein the coil is passively energized by the X-loops, and further wherein the controller is adapted to sequentially power the X-loops and iteratively compare signals generated at a selected one of the Y-loops in at least partially determining a location of the coil relative to the locator grid.

20. The system of claim 18, wherein the coil is actively energized by a power supply provided with the implantable substance delivery device, and further wherein the controller is adapted to iteratively sample and compare signals generated at each of the X-loops in at least partially determining a location of the coil relative to the locator grid.

21. The system of claim 18, wherein the controller is adapted to output an amplitude and phase information of signals that are induced in at least one of the plurality of Y-loops.

22. The system of claim 1, wherein the locator grid includes a plurality of loops extending parallel to one another, the plurality of loops including a central loop and adjacent loops positioned at opposite sides, respectively, of the central loop, and further wherein the controller is adapted to estimate a tilt of the implantable substance delivery device relative to the locator grid based upon an evaluation of symmetry of induced voltages at the central loop and the adjacent loops.

23. The system of claim 1, wherein the controller is coupled to an output indicator, and further wherein the controller is adapted to prompt the output indicator to visually indicate to a clinician a location of the locator grid relative to the fill port opening.

24. A method of externally locating a port opening of a medical substance delivery device implanted at an implant site in a patient, the method comprising:

providing a coil coupled to the medical device and positioned at a known location relative to the port opening;

placing an external locator device proximate the coil, the locator device including a controller electrically coupled to a locator grid including at least one X-loop oriented along a first major axis and at least one Y-loop oriented along a second major axis that is differs from the first major axis;

energizing the coil;

sensing a signal that is induced in at least one of the Y-loops by the energized coil;

determining a location of the coil based upon the sensed signals; and

locating the port opening based upon the determined location of the coil.

25. The method of claim 24, wherein the locator grid includes a plurality of X-loops including a first X-loop and a second X-loop, each of the X-loops oriented along a major axis that is offset from and parallel to the first major axis, and a plurality of Y-loops including a first Y-loop and a second Y-loop, each of the Y-loops oriented along a major axis that is offset from and parallel to the second major axis, and further wherein determining a location of the coil includes comparing signals generated at each of the first and second Y-loops.

26. The method of claim 25, wherein the coil is passively energized by powering of the X-loops, and further wherein determining a location of the coil includes:

energizing the first X-loop to energize the coil and induce a first voltage in the first Y-loop;

sensing a first signal in the first Y-loop relating to the first voltage;

energizing the second X-loop to energize the coil and induce second voltage in the first Y-loop;

sensing a second signal in the first Y-loop relating to the second voltage;

determining which of the first and second signals in the first Y-loop has a larger signal amplitude; and

determining the coil to be relatively nearer to a center of the one of the first and second X-loops providing the larger signal amplitude.

27. The method of claim 25, wherein the coil is passively energized by powering of the X-loops, and further wherein determining a location of the coil includes:

energizing the first X-loop to energize the coil and induce a voltage in the first Y-loop and the second Y-loop;

sensing a first signal in the first Y-loop;

sensing a second signal in the second Y-loop;

determining which of the sensed signals has a larger signal amplitude; and

determining the coil to be relatively nearer to a center of the one of the first and second Y-loops providing the larger signal amplitude.

28. The method of claim 25, wherein the coil is actively energized by a power supply of the implantable substance delivery device, and further wherein determining a location of the coil includes:

energizing the coil;

sensing a first induced voltage signal at the first X-loop;

sensing a second induced voltage signal at the second X-loop;

comparing the first and second induced voltage signals to determine which of the X-loops the coil is more closely positioned.

29. The method of claim 24, wherein the implantable substance delivery device includes first and second coils, the method further comprising:

energizing the first coil at a first parameter;

operating the controller to determine a location of the first coil based upon induced voltages sensed at the Y-loops in response to energization of the first coil;

energizing the second coil at a second parameter different from the first parameter; and

operating the controller to determine a location of the second coil based upon induced voltages at the Y-loops in response to energization of the second coil;

wherein the port opening is located based upon the determined locations of the first and second coils.

30. The method of claim 29, wherein each of the first and second parameters are a frequency.

31. The method of claim 29, wherein each of the first and second parameters are a time period of energization.