Device and method for enabling an orthopedic tool for parameter measurement

• US 8,911,448 B2
• Filed: 09/23/2011
• Issued: 12/16/2014
• Est. Priority Date: 09/23/2011
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Stein, Marc
• Primary Examiner(s): BATES, DAVID W
• Application Number:
  US13/243,169
• Publication Number:
  US 20130076157A1
• Time in Patent Office: 1,180 Days
• Field of Search: 341/32, 606/102
• US Class Current: 606/102
• CPC Class Codes: A61B 2560/0204 of power management
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• CPC Class Codes: A61B 5/4566 Evaluating the spine A61B5/4561 takes 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: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: H01H 36/0006 Permanent magnet actuating reed switches H01H35/147 takes precedence

Abstract

A system for enabling a medical device. The system includes a cradle having a magnet for generating a magnetic field. The cradle supports and aligns the medical device in a predetermined orientation. Medical device placed in the cradle exposes a magnetic sensitive switch to the magnetic field of the magnet that produces a change in state of the magnetic sensitive switch. Medical device further includes a switch, indicator, logic circuitry, delay circuit, and detect circuit for coupling a power source to electronic circuitry. In a first mode of operation the medical device can be turned on and then turned off. In a second mode of operation the medical device cannot be turned off after being turned on.

Claims

1. A method of enabling an orthopedic medical device having an internal power source comprising:

placing the orthopedic medical device in proximity to a magnetic field above a threshold;

maintaining the orthopedic medical device within the magnetic field for greater than a predetermined time period where a magnetic sensitive switch is configured to change state when the orthopedic medical device is within the magnetic field, where the magnetic sensitive switch couples to a delay circuit, where the delay circuit is configured to measure a delay of the predetermined time period after the magnetic sensitive switch changes state;

logic circuitry enabling a switch after the first time period where the switch couples a power source to electronic circuitry, where the delay circuit couples to logic circuitry, where the logic circuitry couples to the switch, and where the logic circuitry is configured to enable the switch when the delay circuit measures the delay of the predetermined time period, the switch configured to couple the power source to electronic circuitry in the medical device when the switch is enabled;

indicating that the orthopedic medical device is enabled by visual, audible, or haptic feedback upon coupling the power source to the electronic circuitry in the medical device; and

the logic circuitry ignoring further changes in the magnetic field after the first time period where the logic circuitry is configured to keep the switch enabled after the predetermined time period.

2. The method of claim 1 further including a step of decoupling a power source from a leakage path to prevent discharge of the power source prior to use of the orthopedic medical device.

3. A method of enabling an orthopedic medical device comprising the steps of:

a magnetic sensitive switch detecting when the orthopedic medical device is within a magnetic field is above a threshold where the magnetic sensitive switch is configured to change state when the orthopedic medical device is within the magnetic field;

a delay circuit measuring a time period the orthopedic medical device is within the magnetic field above the threshold where the magnetic sensitive switch couples to the delay circuit, where the delay circuit is configured to detect the change of state of the magnetic sensitive switch and where the delay circuit is configured to measure when the magnetic sensitive switch has been within the magnetic field greater than a first time period;

logic circuitry enabling a switch to couple a power source to electronic circuitry of the orthopedic medical device when the time period is greater than the first time period, where the delay circuit couples to the logic circuitry, where the logic circuitry couples to the switch, and where the logic circuitry is configured to enable the switch when the delay is greater than the first time period as measured by the delay circuit;

the electronic circuitry initiating a power on reset of the electronic circuitry to initialize internal states of the electronic circuitry of the orthopedic medical device; and

indicating that the orthopedic medical device is enabled by visual, audible, or haptic feedback upon coupling the power source to the electronic circuitry in the medical device.

4. The method of claim 3 further including the steps of:

removing the orthopedic medical device from the magnetic field before the first time period where the magnetic sensitive switch changes state;

the delay circuit responsive to the magnetic sensitive switch where the delay circuit measures that the medical device is removed before the first time period; and

logic circuitry responsive to the delay circuit where the logic circuitry is configured to disable the switch when the medical device is removed from the magnetic field before the first time period where the switch is configured to decouple the power source from the electronic circuitry.

5. The method of claim 3 further including the steps of:

removing the medical device from the magnetic field after a second time period where the second time period is greater than the first time period where the magnetic sensitive switch changes state;

the delay circuit responsive to the magnetic sensitive switch where the delay circuit measures that the medical device is removed after the second time period; and

logic circuitry responsive to the delay circuit where the logic circuitry is configured to keep the switch enabled and where the switch maintains the power source coupled to the electronic circuitry of the medical device.

6. The method of claim 3 further including the steps of:

removing the orthopedic medical device from the magnetic field after the first time period but less than a second time period, where the magnetic sensitive switch is configured to change state when the medical device is removed from the magnetic field, where the delay circuit is configured to detect if the orthopedic medical device has been in the magnetic field for a time period greater than the first time period but less than the second time period; and

logic circuitry responsive to the delay circuit where the logic circuitry is configured to keep the switch enabled and where the switch maintains the power source coupled to the electronic circuitry of the medical device.

7. The method of claim 6 further including a step of performing one or more tests on the orthopedic medical device.

8. The method of claim 6 further including the steps of:

replacing the orthopedic medical device in a magnetic field where the magnetic sensitive switch changes state;

the delay circuit responsive to the magnetic sensitive switch; and

disabling the switch wherein the power source is decoupled from the electronic circuitry where the logic circuitry is responsive to the delay circuit and where the logic circuitry disables the switch when the medical device is placed back in the magnetic field after having been previously removed from the magnetic field after the first time period but before the second time period.

9. The method of claim 3 further including the steps of:

detecting when a voltage of the power source is below a minimum voltage, where the logic circuitry is configured to monitor the voltage of the power source; and

shutting down the orthopedic medical device when the voltage is below the minimum voltage where the logic circuitry is configured to disable the switch thereby decoupling the power source from the electronic circuitry.

10. The method of claim 3 further including a step of disposing of at least a portion of the orthopedic medical device.