Cement restrictor with integrated pressure transducer and method of measuring the pressure at the distal end of a bone canal

• US 7,976,547 B2
• Filed: 12/21/2004
• Issued: 07/12/2011
• Est. Priority Date: 12/21/2004
• Status: Active Grant

• Current Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: Spitzer, Andrew I., Vendrely, Timothy
• Primary Examiner(s): Robert; Eduardo C
• Assistant Examiner(s): Yang; Andrew
• Application Number:
  US11/018,122
• Publication Number:
  US 20060149282A1
• Time in Patent Office: 2,394 Days
• Field of Search: 606 92- 95, 606/102, 606 62- 68, 623 2211- 2338
• US Class Current: 606/95
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/03 Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs A61B5/205 takes precedence
• 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 5/4504 Bones A61B5/4547 takes precedence
• CPC Class Codes: A61F 2/30723 Plugs or restrictors for sealing a cement-receiving space tools for inserting plugs A61F2/4614; sealing collars for use during cementing A61B17/8808
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30327 differing in diameter
• CPC Class Codes: A61F 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/30571 Leaf springs
• CPC Class Codes: A61F 2002/30795 Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2250/0039 differing in diameter

Abstract

A cement restrictor for use in surgical procedures such as total hip replacement, for example, includes a pressure transducer and a transmitter electrically coupled to the pressure transducer. The cement restrictor is configured to be placed at a distal end of a pre-drilled bone canal in a patient'"'"'s femur, for example, such that the pressure transducer may generate an output signal in response to the presence of bone cement injected into the bone canal and around the cement restrictor. The transmitter is configured to transmit this output pressure signal to an external receiver outside the patient'"'"'s body.

Claims

1. A device for implantation into a bone comprising:

a cement restrictor comprising;

a body including a plurality of radial fins extending outwardly therefrom, the body sized to prevent cement injected into a canal in the bone from migrating beyond the distal end of the canal,

a pressure transducer operable to measure the pressure of cement at the distal end of the canal, and

a transmitter electrically coupled to the pressure transducer and configured to transmit an output signal of the pressure transducer,

wherein the pressure transducer and transmitter are secured to the body.

2. The device of claim 1, wherein the transmitter is a radio frequency transmitter.

3. The device of claim 1, wherein the transmitter is an acoustic energy transmitter.

4. The device of claim 1, further including a power source secured to the body and electrically coupled to the pressure transducer and the transmitter.

5. The device of claim 4, wherein the power source is a battery.

6. The device of claim 4, wherein the power source is a ferrite coil configured to produce an electric current when subjected to a magnetic field.

7. The device cement restrictor of claim 1, wherein

the body includes a channel in communication with the surrounding environment, and

the pressure transducer is positioned such that the pressure transducer is also in communication with the surrounding environment via the channel of the body.

8. The device of claim 7, wherein the body is resorbable.

9. The device of claim 7, wherein the body includes high density polyethylene.

10. The device of claim 7, wherein the body includes a threaded bore in communication with the channel and is configured to receive a mating portion of a surgical insertion tool.

11. The device of claim 1, wherein the transmitter includes

a modulator configured to modulate the output pressure signal into a radio wave, and

an antenna configured to transmit the modulated output pressure signal to a remote receiver.

12. A bone cement measurement system for measuring the pressure of the bone cement within a distal portion of a pre-drilled canal of a patient'"'"'s bone, the bone cement measurement system comprising:

a cement restrictor having a body, the body including a plurality of radial fins extending outwardly therefrom, a power source, a pressure transducer electrically coupled to the power source, and a transmitter electrically coupled to the power source to transmit an output signal of the pressure transducer, and

an external receiver to receive the output signal sent from the transmitter.

13. The bone cement measurement system of claim 12, further comprising a display device coupled to the external receiver to display the output signal.

14. The bone cement measurement system of claim 12, wherein the power source is an internal coil and further including an external coil to produce a magnetic field to power the internal coil.

15. A method of measuring the pressure within a distal end of a bone canal during cement pressurization of the canal, the method comprising the steps of:

inserting a body including a plurality of radial fins extending outwardly therefrom and a pressure transducer into the distal end of the bone canal, the body being sized to prevent cement injected into a canal in the bone from migrating beyond the distal end of the canal,

inserting pressurized bone cement into the bone canal,

reading an output signal from the pressure transducer, and

adjusting the pressure of the pressurized bone cement being injected into the bone canal in response to the output signal.

16. The method of claim 15, wherein the step of reading an output signal from the pressure transducer includes transmitting the output signal of the pressure transducer to a remote receiver.

17. A method of injecting pressurized cement into a pre-drilled bone canal, the method comprises the steps of:

injecting pressurized cement at a first pressure into the pre-drilled bone canal,

monitoring the pressure of the pressurized cement at a distal end of the bone canal via a wireless communication originating from a body including a plurality of radial fins extending outwardly therefrom that is positioned within the distal end of the bone canal,

adjusting the pressure of the pressurized cement from the first pressure to a second pressure in response to the monitored pressure of the pressurized cement at the distal end of the bone canal, and

injecting pressurized cement at the second pressure into the pre-drilled bone canal.

18. The method of claim 17, wherein monitoring the pressure of the pressurized cement at the distal end of the bone canal includes reading the pressure at the distal end of the bone canal using an implanted pressure transducer coupled to the body within the distal end of the bone canal and transmitting an output signal of the pressure transducer to a remote receiver.

19. The method of claim 18, wherein transmitting the output signal of the pressure transducer to a remote receiver includes modulating the output signal to a radio frequency wavelength.