Automatic adjusting induction coil treatment device

• US 4,548,208 A
• Filed: 06/27/1984
• Issued: 10/22/1985
• Est. Priority Date: 06/27/1984
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Niemi, Bill H.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/624,871
• Time in Patent Office: 482 Days
• Field of Search: 128/1.5, 128/419 F
• US Class Current: 600/14
• CPC Class Codes: A61N 2/02 using magnetic fields produced by coils, including single turn loops or electromagnets A61N2/12 takes precedence

Abstract

An apparatus for treating a patient which induces an electric current in the body through external application of an electromagnetic field. The apparatus includes means for controlling the magnitude of the induced electric current by sensing the electromagnetic field and automatically controlling its strength. The sensing may be accomplished through time multiplexed use of the field inducing coil or through the use of a separated, dedicated coil.

Claims

1. A medical device for inducing electrical current within a patient'"'"'s body by creating a magnetic field through the body comprising:

first coil for placement in a treatment relation to a patient'"'"'s body;

second coil for placement in a second treatment in relation to the patient'"'"'s body so that the first coil and second coil are in a generally flux-aiding relation to each other;

driver circuitry for providing pulsed electrical energy to the first and second coils;

control means operably connected to the driver circuitry for controlling the magnitude of the electrical energy;

multiplexer means connected to the first coil and second coil and operably connected to the control means for selecting one coil; and

the control means including means for indicating to the multiplexer means that one of the coils is selected for driving by the coil driver and the other of the coils is selected for sensing magnetic field induced by the other coil, and for automatically adjusting the magnitude of electrical energy produced by the driver circuitry based upon sensed magnetic field.

2. The device of claim 1 wherein the control means includes means for periodically sensing and for producing a warning signal if an improper field is sensed.

3. The device of claim 1 wherein the control means includes means for periodically sensing and for automatically adjusting during therapy.

4. A self-fitting electromagnetic bone growth stimulator comprising:

a first treatment coil for positioning adjacent a patient'"'"'s body;

a second treatment coil for positioning adjacent a patient'"'"'s body in a flux-aiding relationship which creates a magnetic field through a portion of the patient'"'"'s body;

pulse generation means electrically connected to the first coil and the second coil for providing pulses of electrical energy to the first coil and the second coil;

control means electrically connected to the pulse generating circuitry for transmitting a magnitude signal to the pulse generation means indicative of a magnitude of the pulses of electrically energy;

sensing circuitry electrically connected to the first and second coils for sensing a magnetic field at one coil, which was produced by the other coil and for producing a sensed field signal indicative of field strength to the control means, the control means automatically adjusting the magnitude signal in response to the field strength signal.

5. The device of claim 4 wherein the control means includes means for periodically sensing and for producing a warning signal if an improper field is sensed.

6. The device of claim 4 wherein the control means includes means for periodically sensing and for automatically adjusting during therapy.

7. A device for automatically self-fitting an induction coil bone growth stimulator of the type having at least two coils for treating a patient comprising:

means for providing pulsed electrical energy to first and second coils;

means connected the first and second coils for selecting one coil as a sense coil;

control means operably connected to the means for providing pulsed electrical energy and the multiplexer means for indicating to the multiplexer means to select one coil for sensing, for sensing electrical current in the sense coil; and

for automatically adjusting electrical energy provided by the means for providing pulsed electrical energy.

8. The device of claim 7 wherein the control means includes means for periodically sensing and producing a warning signal if an improper field is sensed.

9. The device of claim 7 wherein the control means includes means for periodically sensing and automatically adjusting during therapy.