Patent No. 6353763 Pulsed electromagnetic energy treatment apparatus and method

 

Patent No. 6353763

Pulsed electromagnetic energy treatment apparatus and method (George, et al., Mar 5, 2002)

Abstract

A method of and apparatus for the treatment of chronic wounds using pulsed electromagnetic energy provides a constant, known and replicable dosage output which remains unaffected by the capacitance of the patient's body. The apparatus is simple to operate, requiring little operator training or interaction with the apparatus. All specifications of the apparatus relating to the generation and emission of electromagnetic energy are fixed, with the specifications based on actual scientific studies of the various technical parameters involved, such as pulse width and RF dosage. The apparatus includes a pulsed electromagnetic energy generator, a power level controller and one or more thin applicators which can be flexible. The applicators are located immediately adjacent to the patient's body, without the aid of a support member or removal of any dressings or bandages. The generator, which can be battery-operated, is a low power, programmable compact unit whose output is controlled by multiple control circuits for ensuring accurate treatment dosage, for confirming that the treatment was properly administered, and for disabling the generator when appropriate. The generator output is automatically adjusted in response to instructions from the field strength sensor located on or near the applicator. Multiple applicators selected to operate simultaneously at different treatment dosage levels are connected to the generator by multi-conductor cables and readily located directly on the treatment area. Each applicator is a pad including etched printed circuits. The circuits are matched and pre-tuned. An applicator-to-patient proximity detector is also incorporated in or on each applicator and connected to the generator via a power controller to provide for direct monitoring of the treatment site and precise control of treatment dosage.

Notes:

SUMMARY OF THE INVENTION

In view of the foregoing limitations and shortcomings of the prior art, as well as other disadvantages not specifically mentioned above, it should be apparent that there still exists a need in the art for improved electromagnetic energy treatment apparatus and methods. It is therefore a primary object of the present invention to fulfill that need by providing a method of and apparatus for the treatment of chronic wounds using pulsed electromagnetic energy that is cost effective, easy to implement, and ensures proper treatment dosage delivery without the need for manual adjustment of power, pulse rate duration, pulse width duration, treatment time or reactance by the treatment provider.

More particularly, it is an object of this invention to provide an electromagnetic energy treatment apparatus with the ability to produce a constant, known and replicable treatment dosage output that is not adversely affected (i.e., does not negate consistent dosage or efficacy) by the proximity of the body of the patient (e.g., capacitance, inductance).

It is yet another object of this invention to provide an electromagnetic energy treatment apparatus wherein one or more wound sites may be simultaneously treated with different treatment dosages.

It is still another object of this invention to provide an electromagnetic energy treatment apparatus wherein the applicator is easily and accurately positioned directly on or adjacent to the wound site regardless of where the site is located on the patient.

Still another object of this invention is to provide an electromagnetic energy treatment apparatus wherein the applicator includes printed coils formed on one or more printed circuit boards, with the primary coil and secondary coil forming a matching network for effecting a highly efficient RF output. In other words, the applicator includes closely matched and tuned primary/secondary circuits, which greatly enhances efficiency by allowing the use of reduced power levels.

It is a yet further object of this invention to provide an electromagnetic energy treatment apparatus having the ability to affect living tissue by providing an accurate treatment dosage of 1 to 300 mw/cm.sup.2 with very low input power requirements (i.e., an average power requirement in the range of less than three watts, and preferably less than about one watt).

It is a still further object of this invention to provide an electromagnetic energy treatment apparatus wherein treatment dosages are automatically monitored for safety by multiple sensing or detecting circuits and controlled by a field strength sensor.

It is a yet further object of this invention to provide an electromagnetic energy treatment apparatus that is small, portable, easy to use and safe to operate, with the apparatus automatically maintaining the appropriate treatment dosage and shutting down when certain conditions are present.

Briefly described, the present invention is an improved method of and apparatus for generating and administering treatment dosages of pulsed electromagnetic energy for wound healing applications. Specifically, the present invention generates and applies constant, known and replicable treatment dosages of electromagnetic energy of defined specifications to the human body for the purposes of inducing cell proliferation. In its preferred form, the present invention includes a pulsed electromagnetic energy generator, control means, including a power level controller responsive to signals from multiple sensing and control circuits, and one or more interchangeable treatment pad applicators. The generator, which can be battery-operated, is a low power, compact unit whose output is controlled by the multiple sensing and control circuits via the power level controller. The control circuits include integral sensing circuits for ensuring specified treatment dosage and the safety and effectiveness of the apparatus as a medical instrument, and one or more detectors located in or on each applicator for sensing energy output at the site of application and monitoring, with precision, the treatment dosage. Other circuits are included for disabling the apparatus when certain conditions, such as insufficient power, exist.

The generator of the present invention has multiple treatment ports to which one or more applicators are attached via cables to provide for the simultaneous treatment of one or more wound sites on the same patient. Preferably, the apparatus allows the applicators to operate independently and simultaneously at different treatment dosage levels. The applicators are treatment pads of various sizes comprising tuned tank circuits and a field strength sensor to allow for automatic control of the output specifications of the apparatus. Each applicator also has detectors for sensing proximity to the patient during the course of treatment and informing the patient if the applicator inadvertently moves from its intended treatment position.

The present invention has numerous advantages not found in existing electromagnetic energy treatment apparatus. First, the generator of the present invention is operationally efficient and has low power requirements, on the range of less than three watts of average power (preferably less than one watt). This allows the unit to be battery operated and greatly reduced in size, thereby rendering the apparatus portable and easy to use, as the small size facilitates transport and placement of the unit, with minimal disruption, in the patient's treatment area during use.

Another advantage of the present invention relates to its integration of multiple sensor and control circuits which, for the first time, ensures precise treatment dosage and provides confirmation that the applicator remains on the wound site during the entire course of treatment. In addition, these sensor and control circuits allow for unattended operation of the device during treatment, providing for a highly simplified means of treatment. The multiple monitoring and control circuits are separate and distinct, and include a fixed period treatment timer, forward and reflected power monitor circuits (one for each treatment port provided by the generator), an electromagnetic energy signal strength detector and controller circuit, and a treatment pad to patient proximity detector. Together, those control means guarantee that the correct treatment dosage reaches the patient.

Another advantage of the present invention not found in existing electromagnetic treatment devices is the multiple port generator for allowing the simultaneous use of multiple applicators. When using existing electromagnetic treatment devices, caregivers are limited to the treatment of just one wound site per each time interval of unit use. Because many pressure sore patients have two or more wounds, the present invention greatly reduces treatment time and expense since multiple wounds can be treated at once. Preferably, each treatment applicator is selected to operate simultaneously at a different treatment dosage level to accommodate multiple wound sites.

Each treatment applicator of the present invention also includes novel elements which overcome several major deficiencies in previous designs. Existing applicators are typically large volume, rigid extensions of the power sources. The applicator of the present invention is substantially reduced in size, bulk and power requirements. This is possible, in part, due to the utilization of low power and the increased operational efficiency of the generator and applicator itself. Preferably, each applicator is thin, flexible and constructed in any of a wide variety of shapes and sizes to accommodate various wound sites. In one embodiment, the treatment pad is configured as a rectangle with dimensions of approximately 10 inches by 5 inches and a nominal thickness of less than 1/2 inch. Each applicator is a flexible pad comprising one or more etched copper printed circuits laminated between insulating sheets of flexible material having high dielectric properties. The two circuits operate as an impedance matching transformer. Sensing units, including an electromagnetic signal strength detector and an applicator-to-patient proximity detector, are incorporated in each applicator and are in communication with the power level controller to provide for direct monitoring of the electromagnetic energy field and precise control of the treatment dosage. By modifying the topology of the etched printed circuit inductor portion of the LC circuit and then correspondingly adjusting the capacitance value of the capacitor to retune the LC circuit to resonance, the applicator can be constructed in a variety of shapes and sizes to best match the wound size and area on the patient. Moreover, the tank circuit in the applicator is pre-tuned, thereby eliminating the need to manually tune the circuit as it comes into close proximity with the human body or other objects. Given its nominal thickness and increased flexibility, the applicator can be placed over, under or around a bandaged wound site.

Other novel and unique features of the applicator include the following. Existing electromagnetic energy devices do not include mechanisms for delivering precise and replicable treatment dosages to the patient. Although previous designs may have specified that the applicator be tuned to resonance or may have included a mechanism for matching the generator and the applicator in order to minimize SWR, there has been no way to ensure that accurate treatment dosage was being delivered through the coils located in the applicator and beyond, to the surface of the patient's wound site. In the present invention, a signal detector, such as a germanium diode signal detector, is included as part of the applicator for measuring the energy emission from the applicator and supplying a feedback signal to the RF amplifier for controlling energy output. The actual electromagnetic energy field, or treatment dosage, that is transmitted from each applicator is measured directly by embedding the RF signal strength detector inside of the applicator. The signal level from the detector is sent to the power level controller, where it is used as a feedback-control signal to control the output of the RF amplifier of the generator. This direct approach to measuring the actual radiated electromagnetic energy field is a much more precise way to measure the treatment dosage, rather than by indirectly measuring the SWR of the transmitted RF signal. If, at any time, the detector measures a radiated energy output level above or below preset levels, an indicator, such as a "service required" lamp or alarm, audibly, visually or otherwise informs the health care provider and patient of the occurrence and the power level controller switches off the RF amplifier. The forward and reflected power measuring circuits are used to turn the unit off only if either circuit exceeds preset limits. In this manner, the present invention monitors energy emissions from each applicator and ensures that the treatment dosage delivered through each applicator is precise.

The applicator of the present invention is thin and need not be suspended on a mechanical arm, as required by some existing applicators. Because of the unique configuration of the present invention, a correct treatment dosage is easily and effectively delivered to the patient.

The present invention further includes a method of effectively treating chronic wounds such as pressure ulcers involving the precise induction of specific biochemical events associated with cell proliferation. In accordance with the present invention, an electromagnetic field of specified strength and duration is used to stimulate cellular growth and proliferation, membrane ionic flux, growth factor expression, release and functional enhancement, and reductions in cell doubling time. Electromagnetic energy fields are utilized to stimulate and accelerate cell growth and proliferation upon certain types of cells known to be critical to the wound healing process, including fibroblasts and epithelial cells. Electromagnetic stimuli induce cell proliferation by reducing the G.sub.0 and/or G.sub.1 phases of the cell cycle, by stimulating the genetic expression, release and functional enhancement of growth factors, and by inducing the flux of ions across cellular membranes. Therefore, the present invention acts as a mitogen and/or a positive modifier of cellular mitogenic activity. This mitogenic effect results in growth factor stimulation, expression and release, both intra-and extracellularly. A key component of the present method is the specific enhanced actions of fibroblast growth factors.

It is important to note that the present method, which utilizes electromagnetic energy as a stimulus for inducing cell proliferation through mechanisms regulating decreases in cell cycle time, is independent of the particular source of the energy emission or the design of the energy source. The term electromagnetic energy includes effects from its magnetic energy and/or electrical energy components.

The present method utilizes electromagnetic energy as a mitogenic stimulus to reduce cell cycle time through the expression, synthesis and enhanced activity of growth factors, thereby increasing the overall rate of growth and proliferation in various biological cell types, including those found in ephithelial, muscle, connective and neuronal tissues. Energy waves which are primarily defined as Radio Wave frequencies are used to induce biological cell proliferation in vitro under laboratory conditions and in vivo under clinical conditions in intact living organisms. In the electromagnetic spectrum, those frequencies range from 1000 Hertz to 1000 Megahertz, and therefore also include a portion of the audio frequencies (at the lower end) and range through ultra high frequencies (UHF). The present method delivers an electromagnetic treatment energy of 1 to 300 milliwatts per cm.sup.2 to living tissues (in vivo or in vitro). Because it is a specific cellular mitogen, the present method reduces cell cycle time through the induction of specific cellular mechanisms which reduce the duration of the separate and/or combined G.sub.0 and G.sub.1 phases of the cell cycle. Specific mitogenic physical energy signals are provided that induce cell growth and proliferation in part through the induction of ion flux across cellular membranes and subsequent cellular signaling events, including the expression, synthesis and enhanced activity growth factors, especially fibroblast growth factors. An electromagnetic energy stimulus is utilized to activate intracellular and intercellular mechanisms associated with the genetic expression, synthesis and release of biological molecules necessary to regulate cell cycle time.

Because the present method is based upon discoveries pertaining to the effects of specific doses of electromagnetic energy on in vivo and in vitro cells and tissues, the present method offers the significant advantage of fixed power output, pulse rate and pulse width to specifically increase cell growth and proliferation in distinct cell types found in soft tissue, connective tissue, and neuronal cells. Treatments applied using the present method are characterized by specific optimal dosages of pulsed electromagnetic energy to induce cell proliferation of specific cell types. The present method allows utilization of a fixed pulse rate, a fixed pulse width and a fixed energy field strength to define and produce the optimal energy specifications to be used to stimulate specific cell types related to specific medical indications or specific treatment regimens. It also provides for the creation and application of specific dosages and treatment regimens which are required for specific medical indications. Further, the present method can also be implemented to treat wounds other than ulcers, including burns, physical rehabilitation, and neuronal injury.

The present invention has immediate commercial market potential in the treatment of chronic wounds. Beyond that immediate market, the present invention may also be utilized in other treatment areas where increasing the rate of growth and proliferation of human or other living cells is essential, including the treatment of burns and surgically implanted skin or soft tissue grafts, rehabilitation medicine, post surgical repair, and neuronal/brain/spinal injury repair and regeneration. In addition to the medical treatment of soft tissue, the present method has applications in the field of laboratory growth/manufacturing of skin grafts to be sold and used in various surgical settings, veterinary medicine and related fields.

These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the drawings.

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It should be understood that references to wound treatment are not limited to the induction of granulation, epitheliation and vascularization at a wound site, but also includes restoring nutrient load to a wound site, thereby inducing synthesis of growth factors, inducing the synthesis, proliferation and release of fibroblasts, epithelial, endothelial, vascular, muscle and neuronal cell types, inducing macrophage activity in a wound site, increasing mitogenic stimuli, increasing concentration of and inducing effective biological activity of growth factors within a wound site, delivering multiple growth factor therapy to a tissue, altering activity of cell cycle dependent proteins, inducing synthesis and activity of signal transduction molecules, and inducing gene expression in a tissue, among other events. Further, while the present invention is described in terms of human treatment methods, it should be understood that treatment, as used herein, encompasses laboratory applications and procedures as well as veterinary applications and the like.

From the foregoing, it will be appreciated by those skilled in the art that the present invention provides a particularly effective and advantageous method of and apparatus for overcoming many of the limitations associated with the treatment of patients using electromagnetic energy. It will also be readily appreciated by one with ordinary skill in the art to use the method and apparatus of the present invention in other applications, such as veterinary applications.

Although certain presently preferred embodiments of the present invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention.