PEMF biophysical stimulation field generator device and method

• US 6,443,883 B1
• Filed: 06/07/2000
• Issued: 09/03/2002
• Est. Priority Date: 06/08/1999
• Status: Expired due to Fees

• Current Assignee: Hartest Limited
• Original Assignee: Medical Bracing Systems, Ltd.
• Inventors: Ostrow, Alvin S., Tannenbaum, Joseph
• Primary Examiner(s): Lacyk, John P.
• Application Number:
  US09/588,287
• Time in Patent Office: 818 Days
• Field of Search: 600/9-15
• US Class Current: 600/14
• CPC Class Codes: A61N 2/008 for pain treatment or analgesia
• CPC Class Codes: A61N 2/02 using magnetic fields produced by coils, including single turn loops or electromagnets A61N2/12 takes precedence

Abstract

A multi-functional, modular PEMF biophysical stimulation field generator device and healing system using small coils and a PEMF technique to create a high magnetic flux penetration into hard and soft tissues for treatment of a variety of conditions, including fractures and osteoporosis, to achieve an anticipated shorter healing and rehabilitation time. The orthogonally-arranged coils are sequentially-activated to develop a rotating cylindrical energy field focussed on a target area so as to stimulate bone growth. An activation signal having a combined waveform is used to activate the coils, comprising a high frequency carrier wave, which is amplitude-modulated, by a low frequency treatment wave for optimal penetration of biological tissue. In a preferred embodiment, a pre-form wrap is provided as a cast, brace or splint, containing small magnetizing coils, with the wrap being placed circumferentially around the body part containing the treatment site. By virtue of its modular design, the wrap may contain a portable power source, and it may be opened and the coils removed so that they may be placed over, in or under any orthopedic brace, cast, splint or garment. The coils are arranged to insure maximum focussing of the energy to the treatment site. Minimization of the undesired effects of electromagnetic fields on living tissue is achieved by using the small magnetizing coils, thereby preventing electromagnetic field dispersion to adjacent tissues, by a carrier frequency which improves the electromagnetic field concentration at the treatment site, and by the phasic stimulation which improves the electromagnetic beam concentration in the center, further eliminating electromagnetic field dispersion. The PEMF stimulation also develops an electrical field causing tetanic microcontractions in muscle tissue, thereby offsetting muscle atrophy, a common side effect of immobilization, creating gentle exercise loading, inducing bone growth stimulation. The integrated healing system comprising the inventive device, its placement and activation signal, is engineered to provide optimum therapy by combining the beneficial physiological effects resulting from combined device and treatment modalities to optimize and achieve more efficient results through a combined approach.

Claims

1. An activation signal used for generating a PEMF biophysical stimulation field for biomedical applications, applied to at least two pairs of electromagnetic coils, individual ones of each pair being arranged on a pre-form wrap at the respective opposite ends of a pair of orthogonal axes, with said pre-form wrap being disposed proximate a target area, said activation signal comprising:

a pulsed energy level having a random frequency component, comprising a relatively high frequency carrier wave amplitude-modulated by a relatively low frequency treatment wave, wherein said amplitude-modulation introduces a random frequency pattern,

said pulsed energy level being applied simultaneously to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed pulsed electromagnetic fields, and subsequently to the other of said oppositely-arranged coil pair, in sequential, alternating fashion.

2. The signal of claim 1 wherein said pulsed energy level comprises a mixed waveform combined frequency signal, having a high frequency component defining said carrier wave substantially within a range of 10,000 pulses/sec, and a low frequency component defining a square waveform treatment frequency of 25 pulses/sec, each having a duration of 0.020 sec.

3. The signal of claim 2 wherein said square wave treatment frequency avoids uncontrollable DC polarization of said at least one electromagnetic coil, and reduces electrically excited tissue accommodation to a minimum level.

4. The signal of claim 1 wherein said electromagnetic coils develop a current pattern, having a duty cycle of between 5-30 msec ON, and between 5-30 msec OFF.

5. The signal of claim 1 wherein said electromagnetic coils develop a current pattern in said electromagnetic coils, having a duty cycle of 20 msec ON, and 20 msec OFF.

6. The signal of claim 1 wherein each of said coil pairs develops a magnetic field strength of 2.3 Gauss peak and 1.15 Gauss average.

7. The signal of claim 1 simultaneously applied to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed electromagnetic fields, and subsequently applied simultaneously to the other of said oppositely-arranged coil pair, in sequential, alternating fashion, to develop a rotating magnetic field focussed at a treatment site.

8. The signal of claim 7 wherein said focussed, sequentially rotating magnetic field ensures optimal concentration of magnetic flux at said treatment site and decreased energy concentration outside of said treatment site, limiting unwanted dispersion and irradiation of adjacent tissues.

9. The signal of claim 1 wherein each of said oppositely arranged coil pair develops an opposing sequentially alternating vectoral pulsed magnetic field along the axis defined between them, causing said pair of opposing sequentially alternating vectoral magnetic fields to enhance having an additive effect of increased magnetic flux at the center of the intersection of said coil pair axes.

10. A PEMF osteogenesis stimulation device comprising:

a pre-form wrap for placement in proximity to a body portion intended for therapy;

at least two pairs of electromagnetic coils, individual ones of each pair being arranged on said pre-form wrap at the respective opposite ends of a pair of orthogonal axes;

means for generating a pulsed activation signal applied simultaneously to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed pulsed electromagnetic fields, and subsequently to the other of said oppositely-arranged coil pair, in sequential, alternating fashion, said activation signal having a random frequency component,

wherein said activation signal provides PEMF stimulation comprising a relatively high frequency carrier wave amplitude-modulated by a relatively low frequency treatment wave, and wherein said amplitude-modulation introduces a random frequency pattern.

11. The device of claim 10 wherein said pre-form wrap comprises a strap having a plurality of coil housings formed therein about its circumference, each of said at least two pairs of electromagnetic coils being disposed within one of said coil housings, said strap being adapted for placement over a bone fracture treatment site.

12. The device of claim 11 wherein said strap is adapted to be placed over a cast.

13. The device of claim 11 wherein said electromagnetic coils are removably insertable within said coil housings, and are operable separately from them.

14. The device of claim 10 wherein said pre-form wrap has formed therein pockets for embedding said electromagnetic coils therein, said pre-form wrap being adapted for placement over a bone fracture treatment site.

15. The device of claim 10 wherein said pre-form wrap is adapted to be placed under a cast.

16. The device of claim 10 wherein said generating means comprises electronic circuitry for providing said activation signal as a mixed waveform combined frequency signal, having a high frequency component defining said carrier wave substantially within a range of 10,000 pulses/sec, and a low frequency component defining a square waveform treatment frequency of 25 pulses/sec, each having a duration of 0.020 sec.

17. The device of claim 16 wherein said square wave treatment frequency avoids uncontrollable DC polarization of said electromagnetic coils, and reduces electrically excited tissue accommodation to a minimum level.

18. The device of claim 10 wherein said activation signal develops a current pattern in said electromagnetic coils, having a duty cycle of between 5-30 msec ON, and between 5-30 msec OFF.

19. The device of claim 10 wherein said activation signal develops a current pattern in said electromagnetic coils, having a duty cycle of 20 msec ON, and 20 msec OFF.

20. The device of claim 10 wherein said activation signal develops a magnetic field(s) strength in each of said coil pairs of 2.3 Gauss peak and 1.15 Gauss average.

21. The device of claim 10 wherein said pulsed activation signal is simultaneously applied to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed electromagnetic fields, and subsequently applied simultaneously to the other of said oppositely-arranged coil pair, in sequential, alternating fashion, to develop a rotating magnetic field focussed at a treatment site.

22. The device of claim 20 wherein said focussed, sequentially rotating magnetic field ensures optimal concentration of magnetic flux at said treatment site and decreased energy concentration outside of said treatment site, limiting unwanted dispersion and irradiation of adjacent tissues.

23. The device of claim 10 wherein each of said oppositely arranged coil pair develops an opposing sequentially alternating vectoral pulsed magnetic field along the axis defined between them, causing said pair of opposing sequentially alternating vectoral magnetic fields to enhance having an additive effect of increased magnetic flux at the center of the intersection of said coil pair axes.

24. The device of claim 10 wherein said PEMF stimulation develops an electrical field in muscle tissue, developing therein tetanic muscle stimulating microcontractions, thereby offsetting muscle atrophy, whereby said microcontractions provide a desired muscular exercise loading on bone, and simultaneously stimulate bone growth.

25. A method of promoting fracture healing and osteogenesis at a treatment site comprising the steps of:

providing a pre-form wrap for placement in proximity to a body portion intended for therapy;

providing at least two pairs of electromagnetic coils, individual ones of each pair being arranged on said pre-form wrap at the respective opposite ends of a pair of orthogonal axes;

generating a pulsed activation signal applied simultaneously to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed pulsed electromagnetic fields, and subsequently to the other of said oppositely-arranged coil pair, in sequential, alternating fashion, said activation signal having a random frequency component,

wherein said activation signal provides PEMF stimulation to the treatment site comprising a relatively high frequency carrier wave amplitude-modulated by a relatively low frequency treatment wave,

and wherein said amplitude-modulation introduces a random frequency pattern.

26. The method of claim 25 wherein said at least two pairs of electromagnetic coils are arranged on said pre-form wrap for placement over a bone fracture treatment site.

27. The method of claim 25 wherein said at least two pairs of electromagnetic coils are arranged on said pre-form wrap for placement over a cast.

28. The method of claim 25 wherein said at least two pairs of electromagnetic coils are arranged on said pre-form wrap for placement under a cast.

29. The method of claim 25 wherein said generating step is performed by means comprising electronic circuitry for providing said activation signal as a mixed waveform combined frequency signal, having a high frequency component defining a carrier wave substantially within a range of 10,000 pulses/sec, and a low frequency component defining a square waveform treatment frequency of 25 pulses/sec, each having a duration of 0.020 sec.

30. The method of claim 29 wherein said low frequency pulses act as treatment pulses, which avoid uncontrollable DC polarization of said electromagnetic coils, and reduce electrically excited tissue accommodation to a minimum level.

31. The method of claim 25 wherein said activation signal develops a current pattern in said electromagnetic coils, having a duty cycle of between 5-30 msec ON, and between 5-30 msec OFF.

32. The method of claim 25 wherein said activation signal develops a current pattern in said electromagnetic coils, having a duty cycle of 20 msec ON, and 20 msec OFF.

33. The method of claim 25 wherein said activation signal develops a magnetic field strength in each of said coil pairs of 2.3 Gauss peak and 1.15 Gauss average.

34. The method of claim 25 wherein said pulsed activation signal is simultaneously applied to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed electromagnetic fields, and subsequently applied simultaneously to the other of said oppositely-arranged coil pair, in alternating, sequential fashion, to develop a rotating magnetic field focussed at a treatment site.

35. The method of claim 34 wherein said focussed sequentially rotating magnetic field ensures optimal concentration of magnetic flux at said treatment site and decreased energy concentration outside of said treatment site, limiting unwanted dispersion and irradiation of adjacent tissues.

36. The method of claim 25 wherein each of said oppositely arranged coil pair develops an opposing vectorial magnetic field along the axis defined between them, causing said pair of opposing vectorial magnetic fields to have an additive effect of increased magnetic flux at the center of the intersection of said coil pair axes.

37. The method of claim 25 wherein said PEMF stimulation develops an electrical field in muscle tissue, developing therein tetanic microcontractions, thereby offsetting muscle atrophy and creating gentle exercise loading, inducing bone growth stimulation.

38. The method of claim 25 for providing a physiological response in the form of observed osteogenesis comprising a substantial increase in new bone formation at the treatment site, within 2.5 weeks of treatment during a post-operative recovery period.

39. An integrated, multi-functional osteogenesis healing system comprising a PEMF osteogenesis stimulation device operable by application of an activation signal for producing a physiological result in the form of at least one of osteogenesis, soft tissue therapy and muscle stimulation, said system comprising:

a pre-form wrap for placement in proximity to a body portion intended for therapy, said body portion being immobilized by said wrap;

at least two pairs of electromagnetic coils, individual ones of each pair being arranged on said pre-form wrap at the respective opposite ends of a pair of orthogonal axes;

means for applying a pulsed activation signal simultaneously to individual ones of said oppositely arranged coil pair so as to produce oppositely-directed pulsed electromagnetic fields, and subsequently to the other of said oppositely-arranged coil pair, in sequential, alternating fashion, said activation signal having a random frequency component,

wherein said activation signal provides PEMF stimulation comprising a relatively high frequency carrier wave amplitude-modulated by a relatively low frequency treatment wave,

wherein said amplitude-modulation introduces a random frequency pattern,

and wherein said pulsed activation signal comprises a mixed waveform combined frequency signal, having a high frequency component defining said carrier wave substantially within a range of 10,000 pulses/sec, and a low frequency component defining a square waveform treatment frequency of 25 pulses/sec, each having a duration of 0.020 sec.

40. A PEMF biophysical stimulation field for biomedical applications, produced by applying an activation signal to at least two pairs of electromagnetic coils, individual ones of each pair being arranged on a pre-form wrap at the respective opposite ends of a pair of orthogonal axes, with said pre-form wrap being disposed proximate a target area, said PEMF biophysical stimulation field comprising:

a pulsed energy level having a random frequency component, comprising a relatively high frequency carrier wave amplitude-modulated by a relatively low frequency treatment wave, wherein said amplitude-modulation introduces a random frequency pattern,

said pulsed energy level existing simultaneously in individual ones of said oppositely arranged coil pair so as to produce oppositely-directed pulsed electromagnetic fields, and subsequently existing in the other of said oppositely-arranged coil pair, in sequential, alternating fashion,

wherein said activation signal comprises a mixed waveform combined frequency signal, having a high frequency component defining said carrier wave substantially within a range of 10,000 pulses/sec, and a low frequency component defining a square waveform treatment frequency of 25 pulses/sec, each having a duration of 0.020 sec,

said activation signal developing a current pattern in said electromagnetic coils, having a duty cycle of between 5-30 msec ON, and between 5-30 msec OFF,

and said activation signal developing a magnetic field strength in each of said coil pairs of 2.3 Gauss peak and 1.15 Gauss average.

41. An integrated PEMF biophysical stimulation healing system for use at a treatment site comprising:

a pre-form wrap for placement in proximity to a body portion at the treatment site intended for therapy, said body portion being immobilized by said wrap;

an electrotherapeutic system comprising a plurality of electromagnetic coils and an electromagnetic field generator operable to activate said coils by applying thereto a pre-selected activation signal,

said activation signal developing pulsed electromagnetic fields focussed at the treatment site, for providing biophysical stimulation associated with healing.