APPARATUS AND METHOD FOR AIDING FORMATION OF BONE FORMING MATERIAL

• US 3,745,995 A
• Filed: 04/09/1970
• Issued: 07/17/1973
• Est. Priority Date: 04/10/1969
• Status: Expired due to Term

• Current Assignee: Werner Kraus
• Original Assignee: Werner Kraus
• Inventors: Kraus, Werner
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Yasko, J.
• Application Number:
  US05/026,809
• Time in Patent Office: 1,195 Days
• Field of Search: 128/82.1,83,87,92,404,418,419,420,421,1 3/1
• US Class Current: 602/2
• CPC Class Codes: A61B 17/58 for osteosynthesis, e.g. bone plates, screws , setting implements or the like A61B17/14, A61B17/16 take precedence
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals
• 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 and method for aiding formation of bone forming material in the region of a bone structure of a living being, especially a human being, has at least one pick-up coil having first and second terminals, each of which being d.c.-coupled to at least one electrode, each pair of electrodes connected to a respective at least one electrode. Each pair of electrodes straddles a region of the bone structure within which enhanced formation of bone structure, specifically callus, is desired. Field generating means is provided for inducing in the pick-up coil an a.c. current having gentle, gradual slopes, a frequency preferably below 100 c/s, and a magnitude which produces a current density of no more than 10 microamperes per square millimeter at the electrodes.

Claims

1. An apparatus for aiding formation of bone forming material in the region of a bone structure of a living being, comprising, in combination;

at least one pick-up coil having first and second terminals, at least one first electrode of elongated slender shape electrically connected to said first terminal and adapted to be inserted into the bone structure;

said second terminal being adapted to be conductively connected to the bone structure;

a second electrode adapted to be positioned at least partially on the side of the bone structure which is opposite to said first electrode for being d.c.-coupled to a portion of the living being; and

means for inducing in said pick-up coil, and between said electrodes, an a.c. current having gradual, gentle slopes, a frequency below 1,000c/s, and a magnitude which produces a current density of no more than 10 microamperes per square millimeter at said electrodes.

2. The apparatus according to claim 1 wherein said current inducing means comprises a field coil coupled to an a.c. signal generator.

3. The apparatus according to claim 1 wherein said current inducing means comprises the stray fields of the mains.

4. The apparatus according to claim 2 wherein said a.c.signal generator comprises means for superimposing on said a.c.signal a modulating signal having a frequency of at least three times the fRequency of said a.c. signal.

5. The apparatus according to claim 1 for treating a, bone structure having an opening which is a gap caused by a fracture, wherein said second electrode is a metal splint adapted to be attached to the bone structure for fixing it.

6. The apparatus according to claim 5 wherein said metal splint comprises a plate-like member having a circumferential groove housing said pick-up coil.

7. The apparatus according to claim 5 wherein said pick-up coil is wound around a core of a material of low reluctance, said core forming an open-ended magnetic circuit.

8. The apparatus according to claim 1, further including a capacitor connected in parallel to said pick-up coil to form a resonant circuit tuned substantially to the frequency of the induced current.

9. The apparatus according to claim 1, wherein the frequency is below 150 c/s and preferably between 1 and 65 c/s.

10. The apparatus according to claim 1, wherein said frequency is between about 10 and 30 c/s.

11. The apparatus according to claim 1, wherein said harmonics content is below 20 percent and preferably below 10 percent.

12. The apparatus according to claim 1, wherein said current density at said electrodes is below 10 microamperes per square millimeter, and preferably between 3 and 7 microamperes per square millimeter.

13. The apparatus according to claim 1, wherein the coil and the coil leads are insulated up to the point where the electrodes are adapted to enter into the bone structure.

14. The apparatus according to claim 1 wherein said pick-up coil is mechanically connected to a medical splint adapted to reinforce and fix the bone structure.

15. The apparatus according to claim 1 wherein said frequency is between 10 c/s and 1,000 c/s.

16. In an apparatus for aiding formation of bone forming material in the region of a bone structure of a living being including a splint for positioning the bone, and means for securing the splint to the bone, the improvement comprising at least one first electrode of elongated slender shape adapted to be inserted into the bone structure;

a second electrode adapted to be positioned at least partially on the side of the bone structure which is opposite to said first electrode for being d.c.-coupled to a portion of the living being; and

, at least one pick-up coil having a first terminal and a second terminal, said first terminal being connected to said first electrode and said second terminal being adapted to be conductively connected to the bone structure, said coil being adapted to be arranged in inductive relationship with a signal generating means for inducing within said coil an a.c. current having gradual, gentle slopes, a frequency below 1,000 c/s, and a magnitude which produces a current density of no more than 10 microamperes per square millimeter at said electrodes.

17. The apparatus as defined in claim 16, further comprising:

a screw having at least its outer surface made of insulating material and connecting the splint to the bone structure and wherein said first electrode is located within said screw so that said first electrode is insulated from the splint.

18. The apparatus as defined in claim 16, wherein the splint is a plate-like member made of a non-magnetic material and said second terminal is connected to the splint.

19. The apparatus as defined in claim 18, wherein said plate is a sheet-metal member having a thickness not greater than 3 millimeter.

20. The apparatus as defined in claim 16 further comprising a rod-shaped magnetic core and wherein said pick-up coil is wound on said magnetic core.