IMPLANTABLE SENSOR AND ASSOCIATED METHODS

• US 20090187120A1
• Filed: 01/18/2008
• Published: 07/23/2009
• Est. Priority Date: 01/18/2008
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: NYCZ, Jeffrey H.
• Granted Patent: US 8,915,866 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 2090/3908 Soft tissue, e.g. breast tissue
• CPC Class Codes: A61B 2090/3916 Bone tissue
• CPC Class Codes: A61B 2090/3958 emitting a signal
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/107 Measuring physical dimensions, e.g. size of the entire body or parts thereof
• CPC Class Codes: A61B 5/4514 Cartilage
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6878 Bone
• CPC Class Codes: A61B 7/006 Detecting skeletal, cartilage or muscle noise A61B7/003 and A61B7/008 take precedence

Abstract

Implantable sensors and methods for detecting changes in a characteristic of a soft tissue is disclosed. In one embodiment, an implantable sensor for detecting indicators of cartilage wear in a joint is provided. The implantable sensor includes a sensing element for detecting a signal indicative of a characteristic of the cartilage of the joint and a telemetry circuit in communication with the sensing element for transmitting a data set representative of the detected signal. In another embodiment, a system for detecting changes in joint cartilage includes an implantable acoustic sensing element and an external receiver in communication with the implantable acoustic sensing element. In other embodiments, methods of detecting cartilage degradation in a joint and methods of using the disclosed sensors are provided.

Claims

1. An implantable sensor for detecting indicators of soft tissue wear of a joint, comprising:

a sensing element for implantation into a portion of a bone adjacent the joint, the sensing element having an external surface to maintain the sensing element in a fixed position within the bone, the sensing element for detecting a signal indicative of a characteristic of the soft tissue of the joint; and

a telemetry circuit in communication with the sensing element adapted for transmitting a data set representative of the detected signal outside of the bone.

2. The implantable sensor of claim 1, wherein the sensing element detects acoustic signals.

3. The implantable sensor of claim 2, wherein the signal indicative of a characteristic of the soft tissue of the joint is an audible sound produced during movement of the joint.

4. The implantable sensor of claim 2, wherein the signal indicative of a characteristic of the soft tissue of the joint is a vibration produced during movement of the joint.

5. The implantable sensor of claim 1, wherein the sensing element includes at least two sensors operable to determine an impedance between the at least two sensors, each of the at least two sensors having an outer surface for engaging a portion of a bone adjacent the joint and for maintaining each sensor in a fixed position within the bone.

6. The implantable sensor of claim 5, wherein at least one of the at least two sensors is configured for placement in a distal portion of a femur adjacent a knee joint.

7. The implantable sensor of claim 6, wherein at least one of the at least two sensors is configured for placement in a proximal portion of a tibia adjacent the knee joint.

8. The implantable sensor of claim 1, wherein the sensing element is further adaptable to monitor wear of an artificial joint.

9. A system for detecting changes in joint cartilage, comprising:

an implantable acoustic sensor for detecting an acoustic signal indicative of a characteristic of the joint cartilage and communicating a data set representative of the detected signal to an external receiver, wherein the implantable acoustic sensor is suitable for injection into a tissue adjacent the joint; and

an external receiver in communication with the implantable acoustic sensor, the external receiver for receiving the data set representative of the detected signal from the implantable acoustic sensor.

10. The system of claim 9, wherein the sensor is adapted for detecting sounds associated with joint motion.

11. The system of claim 9, wherein the sensor is adapted for detecting vibrations associated with joint motion.

12. The system of claim 9, further comprising a plurality of implantable acoustic sensors.

13. The system of claim 12, wherein the plurality of implantable acoustic sensors operate as redundancies.

14. The system of claim 12, wherein the plurality of implantable acoustic sensors operate together as an array.

15. The system of claim 9, wherein the sensor is adapted for percutaneous implantation.

16. The system of claim 15, wherein the sensor is substantially cylindrical.

17. The system of claim 16, wherein the sensor has a diameter less than 4 mm.

18. A method of detecting soft tissue degradation in a joint, comprising:

providing at least one acoustic sensor for detecting a signal indicative of a characteristic of the soft tissue of a joint, the at least one sensor having an external surface configured for implantation within a bone;

implanting the at least one sensor into a bone adjacent the joint;

operating the at least one sensor to detect a reference signal indicative of the characteristic of the soft tissue;

operating the at least one sensor to detect a subsequent signal indicative of the characteristic of the soft tissue; and

comparing the subsequent signal to the reference signal to detect changes in the characteristic of the soft tissue.

19. The method of claim 18, further comprising:

operating the at least one sensor to detect a plurality of subsequent signals indicative of the characteristic of the soft tissue; and

comparing each of the plurality of subsequent signals to the reference signal to detect changes in the characteristic of the soft tissue.

20. The method of claim 19, further comprising:

determining the detected changes in the characteristic of the soft tissue are indicative of soft tissue degradation; and

performing a joint replacement procedure, including implanting an artificial joint.

21. The method of claim 20, wherein performing the joint replacement procedure includes utilizing the at least one sensor as a reference marker.

22. The method of claim 18, wherein the at least one sensor is further configured to detect wear of the artificial joint.

23. The method of claim 18, wherein implanting the at least one sensor is performed percutaneously.

24. A method, comprising:

providing a plurality of implantable sensors for detecting signals indicative of a characteristic of cartilage of a joint, the plurality of implantable sensors configured for detecting impedance;

implanting each of the plurality of sensors into a bone adjacent the joint;

operating the plurality of sensors to detect a reference signal indicative of the characteristic of the cartilage;

operating the plurality of sensors to detect a subsequent signal indicative of the characteristic of the cartilage; and

comparing the subsequent signal to the reference signal to detect any changes in the characteristic of the cartilage.

25. The method of claim 24, wherein the plurality of implantable sensors are paired such that each pair of sensors is capable of detecting an impedance indicative of the characteristic of the cartilage.