Edge-detect receiver for orthopedic parameter sensing

• US 8,939,030 B2
• Filed: 05/24/2013
• Issued: 01/27/2015
• Est. Priority Date: 06/29/2010
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Stein, Marc, Kelly, Andrew
• Primary Examiner(s): Gibson, Randy W
• Assistant Examiner(s): HULS, NATALIE F
• Application Number:
  US13/902,704
• Publication Number:
  US 20130261450A1
• Time in Patent Office: 613 Days
• Field of Search: 735/84, 736/58
• US Class Current: 73/584
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 5/4585 Evaluating the knee
• 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 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: G01N 29/44 Processing the detected response signal , e.g. electronic circuits specially adapted therefor digital signal processing per se G06F17/00

Abstract

A sensor system uses positive closed-loop feedback to provide energy waves into a medium. The medium can be coupled to the muscular-skeletal system or be part of the muscular-skeletal system. A sensor comprises one or more transducers, an edge detect circuit or a reflecting surface. A parameter is applied to the medium and the parameter affects the medium. A transducer receives an energy wave that has traversed the medium and generates an energy wave signal. The edge-detect receiver receives the energy wave signal signal from the transducer and generates a pulse upon sensing a leading edge corresponding to a wave front of the energy wave. The edge-detect receiver comprises a preamplifier, a differentiator, a digital pulse circuit, and a deblank circuit. The transit time, phase, or frequency is measured of the propagating energy waves and correlated to the parameter being measured.

Claims

1. A sensor for measuring a parameter of the muscular-skeletal system where the parameter being measured affects a medium, where the medium is coupled to or part of the muscular-skeletal system, where the medium is configured to receive at least one pulsed energy wave that traverses the medium, where a time, frequency, or phase is measured of the at least one pulsed energy wave and converted to the parameter and where the sensor comprises:

an edge detect circuit configured to detect a pulsed energy wave that has traversed the medium where the edge detect circuit comprises;

a differentiator configured to receive a pulsed energy wave signal that corresponds to the pulsed energy wave that has traversed the medium where the differentiator is configured to detect a change in slope;

a pulse circuit coupled to the differentiator configured to generate a pulse upon detecting a leading edge of the pulsed energy wave signal; and

a deblank circuit coupled to the pulse circuit where the deblank circuit is configured to support desensitizing the edge detect circuit to trailing signals of the pulsed energy wave signal after the leading edge of the pulsed energy wave signal is detected.

2. The sensor of claim 1 further including a first transducer where the first transducer is configured to couple to the medium at a first point and where the first transducer is configured to transmit pulsed energy waves into the medium.

3. The sensor of claim 2 further including a second transducer where the second transducer is configured to couple to the medium at a second point and where the second transducer couples to the edge detect circuit.

4. The sensor claim 3 where the second transducer is configured to receive pulsed energy waves from the medium and where the second transducer is configured to output the pulsed energy wave signal corresponding to a received pulsed energy wave.

5. The sensor or claim 2 further including a reflective surface where the reflective surface is configured to couple to the medium at a second point.

6. The sensor of claim 5 where the reflective surface is configured to reflect pulsed energy waves back to the first point of the medium, where the first transducer is configured to receive pulsed energy waves, where the first transducer couples to the edge detect circuit, and where the first transducer is configured to output the pulsed energy wave signal corresponding to a received pulsed energy wave.

7. The sensor of claim 1 further including a preamplifier coupled to the differentiator where the preamplifier is configured to receive and amplify the pulsed energy wave signal.

8. The sensor of claim 7 where the deblank circuit couples to the preamplifier and where the deblank circuit initiates one of gain reduction of the preamplifier, decoupling of an input of the preamplifier from receiving the pulsed energy wave signal, changing the frequency response of the preamplifier, or disabling the preamplifier for a predetermined time whereby the edge detect circuit is desensitized from responding to trailing portions of the pulsed energy wave signal.

9. The sensor of claim 1 where the change in slope detected by the differentiator comprises a change in current.

10. The sensor of claim 9 where the change in current corresponds to detection of the leading edge of the pulsed energy wave.

11. A sensor for measuring a parameter of the muscular-skeletal system where the parameter being measured affects a medium, where the medium is coupled to or part of the muscular-skeletal system, where the medium is configured to receive at least one pulsed energy wave that traverses the medium, where a time, frequency, or phase is measured of the at least one pulsed energy wave and converted to the parameter and where the sensor comprises:

a transducer coupled to the medium at a first point; and

an edge detect circuit configured to detect a pulsed energy wave that has traversed the medium where the edge detect circuit comprises;

a differentiator configured to receive a pulsed energy wave signal that corresponds to the pulsed energy wave that has traversed the medium where the differentiator detects a change in slope of the pulsed energy wave signal;

a pulse circuit coupled to the differentiator configured to generate a pulse on detecting a leading edge of the pulsed energy wave; and

a deblank circuit coupled to the pulse circuit where the deblank circuit is configured to support desensitizing the edge detect circuit to trailing signals of the pulsed energy wave signal after the leading edge of the pulsed energy wave signal is detected.

12. The sensor of claim 11 further including a second transducer at a second point of the medium where the transducer is configured to transmit pulsed energy waves into the medium, where the second transducer couples to the edge detect circuit, and where the second transducer is configured to generate the pulsed energy wave signal corresponding to the pulsed energy wave.

13. The sensor claim 11 where a reflective surface is coupled to the medium at a second point, where the reflective surface is configured to reflect pulsed energy waves back to the first point of the medium, where the transducer is configured to receive pulsed energy waves, and where the first transducer is configured to output the pulsed energy wave signal corresponding to a received pulsed energy wave.

14. The sensor of claim 11 further including a preamplifier coupled to the differentiator where the preamplifier is configured to receive and amplify the pulsed energy wave signal and where the deblank circuit is configured to blank the preamplifier from amplifying a remaining portion of the pulsed energy wave signal when the leading edge of the pulsed energy wave is detected.

15. The sensor of claim 11 further including a preamplifier coupled to the differentiator where the deblank circuit couples to the preamplifier and where the deblank circuit initiates one of gain reduction of the preamplifier, decoupling of an input of the preamplifier from receiving the pulsed energy wave signal, changing the frequency response of the preamplifier, or disabling the preamplifier for a predetermined time.

16. A sensor for measuring a parameter of the muscular-skeletal system where the parameter being measured affects a medium, where the medium is coupled to or part of the muscular-skeletal system, where the medium is configured to receive at least one pulsed energy wave that traverses the medium, where a time, frequency, or phase is measured of the at least one pulsed energy wave and converted to the parameter and where the sensor comprises:

an edge detect circuit configured to detect a pulsed energy wave that has traversed the medium where the edge detect circuit comprises;

a preamplifier configured to receive a pulsed energy wave signal that corresponds to the pulsed energy wave where the preamplifier is configured to receive and amplify the pulsed energy wave signal;

a differentiator coupled to the preamplifier where the differentiator is configured to receive the pulsed energy wave signal to detect a change in slope;

a pulse circuit coupled to the differentiator configured to generate a pulse on detecting a leading edge of the pulsed energy wave; and

a deblank circuit coupled to the preamplifier where the deblank circuit is configured to blank the preamplifier from amplifying a remaining portion of the pulsed energy wave signal after the leading edge of the pulsed energy wave is detected.

17. The sensor of claim 16 further including:

a first transducer coupled to a first point of the medium where the first transducer is configured to transmit pulsed energy waves into the medium;

a second transducer coupled to a second point of the medium where the second transducer is configured to receive pulsed energy waves from the medium, where the second transducer couples to the edge detect circuit, and where the second transducer is configured to generate the pulsed energy wave signal corresponding to received pulsed energy waves.

18. The sensor claim 16 further including:

a first transducer coupled to a first point of the medium where the first transducer is configured to transmit pulsed energy waves into the medium;

a reflective surface coupled to the medium at a second point, where the reflective surface is configured to reflect pulsed energy waves back to the first point of the medium, where the first transducer is coupled to the edge detect circuit, where the first transducer is configured to receive pulsed energy waves, and where the first transducer is configured to output the pulsed energy wave signal corresponding to a received pulsed energy wave.

19. The sensor of claim 16 where the change in slope detected by the differentiator comprises a change in current.

20. The sensor of claim 19 where the change in current corresponds to detection of the leading edge of the pulsed energy wave.