Surgery – Magnetic field applied to body for therapy – Electromagnetic coil
Reexamination Certificate
1999-09-09
2001-01-30
Lacyk, John P. (Department: 3736)
Surgery
Magnetic field applied to body for therapy
Electromagnetic coil
C600S015000
Reexamination Certificate
active
06179772
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to pulsed electromagnetic field (PEMF) coils for the treatment of injuries in a patient, and more specifically to methods and apparatuses relating to portable PEMF coils, and PEMF coils with high field strength and field generating efficiency.
BACKGROUND OF THE INVENTION
Traditional methods for treating certain injuries to a body (e.g., humans, animals) involve setting and immobilizing the injured member to allow natural healing of the injury. Often, it is desirable that natural healing will restore damaged structures to their original uninjured condition without-significant inconvenience to a patient. Traditional problems in injury treatments have been associated with the inability of the patient's body to heal correctly or rapidly and the inability of the healed part to regain full strength and freedom of movement. These problems are especially acute in patients with suboptimal health and reduced healing capacity such as the elderly, the bedridden, or patients with multiple disorders.
Attempts to address these problems and to promote more rapid healing have led to the use of pulsed electromagnetic fields. It is generally known that electromagnetic fields applied to a body can produce favorable biological effects. For example, FDA approved pulsed electromagnetic field (PEMF) apparatuses are available for use in bone healing. These apparatuses are used to augment and accelerate the natural healing process. PEMF is also effective in the treatment of severe injuries and fractures which are not otherwise treatable using conventional techniques.
Known methods and apparatuses which have been used to treat injuries using PEMF include the use of Helmholtz and toroidal coils to deliver PEMF. These methods and apparatuses have suffered from various deficiencies. For example, Helmholtz coils suffer from field inhomogeneity and field dropouts (e.g., the field drops to zero near the center of the coil). Toroidal coils are inefficient and have a relatively weak field strength. Further, known methods of PEMF treatment have problems associated with system complexity, large size and weight, long treatment times, weak PEMF strength and low efficiencies in promoting healing. Current devices and methods of PEMF treatment further fail to provide adequate mobility during treatment. Existing magnetic coil devices typically rely on spatial separation of the opposing sides of the coils to prevent detrimental interference of the magnetic fields. To achieve spatial separation, typically, a relatively thick and bulky core is implemented. A thick or bulky core can make it difficult to wrap or position the coil in certain treatment areas, for example, a patient's fingers. Other drawbacks also exist.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome these and other drawbacks of the prior art.
It is another object of the invention to provide a PEMF apparatus that is relatively small, light and thin yet which generates a relatively strong magnetic flux per unit length.
It is another object of the present invention to provide a PEMF apparatus using a coil design that produces a single polarity magnetic field that is relatively homogenous and that maintains its field strength even at distances spaced from the coil.
It is another object of the present invention to provide a PEMF apparatus using a planar coil with a core comprising a magnetic shielding material.
It is another object of the present invention to provide a PEMF apparatus sized to allow PEMF treatment while a patient is mobile and engaged in physical activity.
It is another object of the present invention to provide a PEMF apparatus which can be incorporated as part of a cast or attached to the outside of a cast to augment the natural healing abilities of the body.
It is another object of the present invention to provide an efficient method to energize a coil to produce a single polarity PEMF that eliminates or minimizes ringing without the need for a shunt diode across the coil.
It is another object of the present invention to provide a coil for use in PEMF treatment which is deformable, flexible and pliant and easily adaptable for the application of an electromagnetic field to injuries at any location on a patient's body.
To accomplish these and other objects of the present invention, one preferred embodiment of the invention is directed to a PEMF apparatus having a coil wrapped around a core in a generally rectangular configuration with a magnetic shield located within the core. The coil comprises a plurality of turns of an electrical conductor, preferably with each turn having a length to width ratio of at least five. The apparatus may be deformable, flexible and pliant, and may be shaped to conform to portions of a patient's body. Advantageously, both the top and bottom surfaces of the apparatus will produce a substantially homogeneous. unipolar. non-inverting PEMF with little or no field dropout. The top and the bottom surface generate PEMF of opposite polarity. Preferably the surface generating the North (N) polarity of the magnetic field may be positioned proximal to the portion of the patient to be treated.
According to another preferred embodiment, the core comprises a first end portion and a second end portion of a spacer material such as wood, plastic, foam, or other material which defines a width, height and thickness. The first and second end portions may be separated by a space therebetween. A sheet of magnetic shielding material such as metal is wrapped around the first and second end portions to define a core with an inner surface and a top surface. A plurality of turns of an electrical conductor may be wound around the first end portion, the bottom surface, the second end portion and the top surface to form a coil. The components of the core may be attached to each other and to the coil by suitable adhesives. For example, epoxy may be used to attach the components.
According to another preferred embodiment, a PEMF treatment apparatus for PEMF treatment of a patient while the patient is engaged in active physical activity is disclosed. The PEMF treatment apparatus preferably comprises a coil wrapped around a flexible core, a power supply and a solid state switching circuit connected between the power supply and the coil to drive the coil with a current at a periodic pulsed frequency to generate a non-inverting PEMF. The power supply is preferably a battery.
According to another preferred embodiment, a PEMF coil is disclosed that is relatively small, thin and light yet generates a relatively strong magnetic flux per unit length. Preferably, a relatively small gauge wire is used to wind the coil. According to one embodiment, the PEMF coil is wrapped around a core which is of a relatively thin cross section. A core of relatively thin cross section may be achieved for certain embodiments of the invention by implementing layers of magnetic shielding material. The magnetic shielding material reduces the magnetic interference from opposing sides of the coil without the need for a relatively large spatial separation. Layers of magnetic shielding material are, preferably, interspaced between relatively thin layers of insulating material.
REFERENCES:
patent: 4105017 (1978-08-01), Ryaby et al.
patent: 5181902 (1993-01-01), Erickson et al.
patent: 5192263 (1993-03-01), Kraus
patent: 5195940 (1993-03-01), Baylink
patent: 5195941 (1993-03-01), Erickson et al.
patent: 5267939 (1993-12-01), Liboff et al.
patent: 5269745 (1993-12-01), Liboff et al.
patent: 5269747 (1993-12-01), Erickson et al.
patent: 5290409 (1994-03-01), Liboff et al.
patent: 5312534 (1994-05-01), Liboff et al.
patent: 5314401 (1994-05-01), Tepper
patent: 5316634 (1994-05-01), McLeod
patent: 5318561 (1994-06-01), McLeod et al.
patent: 5330410 (1994-07-01), Baylink
patent: 5338286 (1994-08-01), Abbott et al.
patent: 5351389 (1994-10-01), Erickson et al.
patent: 5376245 (1994-12-01), McLeod
patent: 5401233 (1995-03-01), Erickson et al.
patent: 5415617 (1995-05-01), Kraus
Hunton & Williams
Lacyk John P.
Orthosoft, LLC
LandOfFree
Magnetic coil for pulsed electromagnetic field does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic coil for pulsed electromagnetic field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic coil for pulsed electromagnetic field will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499692