Skeletal tissue stimulator and a low voltage oscillator circuit for use therein

• US 4,665,920 A
• Filed: 11/28/1984
• Issued: 05/19/1987
• Est. Priority Date: 11/28/1984
• Status: Expired due to Fees

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Campbell, Wayne A.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/675,725
• Time in Patent Office: 902 Days
• Field of Search: 128/419 F, 128/421-422, 128/241, 331/111, 331/113 R, 331/423 R
• US Class Current: 607/51
• CPC Class Codes: A61F 2002/2821 Bone stimulation by electromagnetic fields or electric current for enhancing ossification
• CPC Class Codes: A61N 1/326 for promoting growth of cells, e.g. bone cells

Abstract

A skeletal tissue stimulator and especially a bone growth stimulator 10 and a circuit 12 adapted to be coupled to the skeletal tissue in a body, and especially bone tissue in the body, whose growth is to be stimulated, which tissue acts as a load 22 for the circuit 12. The circuit 12 has a battery 24 and an oscillator circuit 26 which is adapted to be coupled to the load 22. The oscillator circuit 26 is coupled to a storage device 28 which is charged from the battery 24 and discharged through the load 22. The storage device 28 controls the state of the oscillator circuit 26 which in turn controls current flow from the battery 24 directly through load 22. The bone growth stimulator 10 and circuit 12 are characterized in that all the current provided by the battery 24 must flow through the load 22, either directly from the oscillator circuit 26 or as a result of discharge from the storage device 28.

Claims

1. An implantable low voltage oscillator circuit, capable of being coupled to a portion of the body which body acts as a load to said circuit, comprising:

a battery having a first terminal and a second terminal;

an oscillator having a first state and a second state and being operatively coupled to said first terminal of said battery;

capacitive storage means operatively coupled between said oscillator and said second terminal of said battery for controlling the oscillation of said oscillator;

charge means operatively coupled to said capacitive storage means, said charge means for charging said capacitive storage means when said oscillator is in said first state; and

discharge means operatively coupled to said capacitive storage means and capable of being coupled to said load, said discharge means for discharging said capacitive storage means through said load when said oscillator means is in said second state;

said capacitive storage means and said load being the only current paths to or from said second terminal of said battery.

2. A skeletal tissue stimulator capable of being coupled to said skeletal tissue which acts as a load for said stimulator, comprising:

a battery having a first terminal and a second terminal, said second terminal capable of being coupled to said skeletal tissue at a first location;

a latch operatively coupled to said first terminal of said battery and capable of being coupled to said skeletal tissue at a second location, said latch having a first state and a second state, said latch for allowing electrical current to flow between said battery and said skeletal tissue when said latch is in said first state but not allowing electrical current to flow between said battery and said skeletal tissue when said latch is in said second state;

a capacitor operatively coupled between said latch and said second terminal of said battery, said capacitor for controlling said latch to said first state when said capacitor is substantially discharged and for controlling said latch to said second state when said capacitor is substantially charged;

charging means operatively coupled to said battery and said capacitor for charging said capacitor from said battery when said latch is in said first state; and

discharge means operatively coupled to said capacitor and capable of being coupled to said skeletal tissue for allowing said capacitor to discharge through said skeletal tissue when said latch is in said second state.

3. A skeletal tissue stimulator adapted to be coupled to a load, a portion of which is adapted to be said skeletal tissue, comprising:

a battery; and

an oscillator circuit coupled to said battery and adapted to be coupled to said load;

said oscillator circuit having a first state in which current is allowed to flow between said battery and said load and having a second state in which current is not allowed to flow between said battery and said load;

said oscillator circuit having a storage element adapted to be arranged in parallel with said load, said storage element being charged from said battery and being adapted to be discharged through said load;

said stimulator characterized in that all current provided by said battery must flow through either said storage element or said load.