SENSING MODULE HAVING A PIEZO-RESISTIVE SENSOR FOR ORTHOPEDIC LOAD SENSING INSERT DEVICE

• US 20100326211A1
• Filed: 06/29/2010
• Published: 12/30/2010
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Stein, Marc
• Granted Patent: US 8,245,583 B2
• Time in Patent Office: Days
• US Class Current: 73/862.636
• CPC Class Codes: A61B 5/4509 Bone density determination
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: A61B 5/6878 Bone
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 8/15 Transmission-tomography

Abstract

A sensing insert device (100) is disclosed for measuring a parameter of the muscular-skeletal system. The sensing insert device (100) can be temporary or permanent. Used intra-operatively, the sensing insert device (100) comprises an insert dock (202) and a sensing module (200). The sensing module (200) is a self-contained encapsulated measurement device having at least one contacting surface that couples to the muscular-skeletal system. The sensing module (200) comprises one or more sensing assemblages, electronic circuitry (307), an antenna (2302), and communication circuitry (320). The sensing assemblages are between a top plate (1502) and a bottom plate (1504) in a sensing platform (121). The sensing assemblages comprise a load disc (2004) and a piezo-resistive sensor (2002) to measure the parameter. An elastic support structure or springs (1108) is coupled between the top plate (1502) and the bottom plate (1504) to prevent cantilevering of a surface.

Claims

1. A sensing module for measuring a parameter of the muscular-skeletal system comprising:

a sensing platform where the sensing platform includes;

a first substrate;

a second substrate; and

at least three sensing assemblages coupled between the first and second substrates and where each sensing assemblage includes a piezo-resistive sensor,

at least one elastic support between the first and second substrate.

2. The sensing module of claim 1 further including where the parameter is applied to the first substrate, where each sensing assemblage couples to a predetermined location on the first substrate, and where a location where the parameter is applied on the first substrate is determined by a comparison of the measurements from the at least three sensing assemblages.

3. The sensing module of claim 1 further including at least one elastic support between the first and second substrate.

4. The sensing module of claim 3 where the at least one elastic support comprises:

a spring assembly comprising;

a disc spring; and

a spring retainer coupled to the disc spring to retain the disc spring in a predetermined position.

5. The sensing module of claim 3 where the disc spring returns the first substrate to a predetermined position when a force, pressure, or load is removed.

6. The sensing module of claim 5 where the at least one elastic support prevents cantilevering of the first substrate.

7. The sensing module of claim 1 further including a load disc in the sensing assemblage where the load disc transfers a force, pressure, or load to the piezo-electric sensor.

8. The sensing module of claim 7 further including an encapsulating enclosure where the sensing platform resides in the encapsulating enclosure and where the encapsulating enclosure supports the second substrate.

9. The sensing module of claim 8 where the encapsulating enclosure comprises:

a housing where the sensing platform partially resides in the housing;

a cap overlying the first substrate;

a seal between the cap and the housing where the seal allows movement of the cap under a force, pressure, or load applied to the cap.

10. The sensing module of claim 9 where electronic circuitry operatively coupled to the at least three sensing assemblages is between the second substrate and a bottom surface of the housing.

11. A sensing platform for measuring a parameter of the muscular-skeletal system comprising:

a first substrate;

a second substrate; and

at least one sensing assemblage coupled between the first and second substrates comprising;

a piezo-resistive sensor;

a load disc coupled to the piezo-resistive sensor.

12. The sensing platform of claim 11 where the load disc transfers a force applied to the first substrate to the piezo-resistive sensor.

13. The sensing platform of claim 12 where the load disc has a major surface of a predetermined area coupling to the piezo-resistive sensor.

14. The sensing platform of claim 13 further including at least one elastic support coupled between the first and second substrates.

15. The sensing platform of claim 14 where the load disc is adhesively fastened to piezo-resistive sensor.

16. A sensing module to measure a parameter of the muscular-skeletal system comprising:

a sensing platform where the sensing platform includes;

a first substrate;

a second substrate;

at least one sensing assemblage coupled between the first and second substrates;

a housing where the sensing platform partially resides in the housing;

a cap overlying the first substrate; and

a seal between the cap and the housing where the seal allows movement of the cap under a force, pressure, or load applied to the cap.

17. The sensing module of claim 16 further including at least one elastic support between the first and second substrates.

18. The sensing module of claim 17 where the at least one sensing assemblage includes a sensor and where the sensor comprises one of a piezo-resistive sensor, MEMS sensor, strain gauge, or mechanical sensor.

19. The sensing module of claim 18 where the second substrate is supported by a ledge on an interior wall of the housing and where electronic circuitry operatively coupled to the sensing assemblage resides between the second substrate and the bottom of the housing.

20. The sensing module of claim 19 where the sensing assemblage comprises a load disc coupled to the sensor.