Pulsed electromagnetic energy treatment apparatus and method

Abstract

An apparatus and method for the treatment of chronic wounds using electromagnetic energy. The apparatus includes a generator and at least one applicator. The generator can produce electromagnetic energy and the applicator can apply the electromagnetic energy produced by the generator. A detector is disposed on the applicator that can measure the field strength of the electromagnetic energy applied.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation application of U.S. patent application Ser. No. 09 / 994,598, entitled IMPROVED PULSED ELECTROMAGNETIC ENERGY TREATMENT APPARATUS AND METHOD, filed on Nov. 20, 2001, which is a continuation application of U.S. patent application Ser. No. 09 / 231,790, entitled IMPROVED PULSED ELECTROMAGNETIC ENERGY TREATMENT APPARATUS AND METHOD, filed on Jan. 15, 1999, which claims priority of an earlier filed provisional application U.S. Ser. No. 60 / 071,396, filed on Jan. 15, 1998, the entire content of which is incorporated herein by reference.TECHNICAL FIELD OF THE INVENTION [0002] This invention related to electromechanical devices and methods for therapeutically treating human body tissue, and more particularly to a device for and a method of stimulating cell proliferation and related molecular events using high frequency pulsed electromagnetic energy. BACKGROUND OF THE INVENTION [0003] The present invention i...

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Benefits of technology

[0035] 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.

[0036] 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.

[0037] 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 ½ 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.

[0038] 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.

[0039] 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.

[0040] 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 G0 and / or G1 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.

Problems solved by technology

However, clinical studies have been disappointing and some experts have suggested that an alternative to single growth factors as therapeutic agents is the utilization of growth factors in combination to elicit synergistic clinical efficacy.

This lack of therapeutic efficacy may be in part because wound healing is a complex programmed sequence of cellular and molecular events, including macrophage activation during inflammation, cell migration, angiogenesis, provisional matrix synthesis, synthesis of collagen by fibroblasts, and reepithelialization.

Current pharmaceutical approaches do not fully mimic the necessary spatial and temporal patterns of growth factor activity needed to promote wound healing.

Overall, the complexity and variability of clinical wounds have limited pharmacological approaches to accelerate wound healing, leaving dressings and nonpharmacological ancillary modalities to dominate the market associated with wound management.

However, a subcategory of these devices utilize pulsed electromagnetic energy output to theoretically stimulate tissue without inducing a thermal response, although this has never been completely proven to occur using existing devices.

In the United States, where wound care constitutes less than 1% of aggregate health care dollars, treating and managing pressure ulcers requires an inordinate amount of material, human resources, time and money.

The costs associated with managing just one type of chronic wound alone, pressure ulcers, are extraordinary.

Application of external electrical and electromagnetic fields is now an increasingly standard therapy for the treatment of nonunion bone fractures, but these devices have seen limited use in other areas of healing.

Unfortunately, this has led to unsubstantiated claims that electrical stimulation cures a wide variety of health problems, thereby alienating the medical profession.

Moreover, published reports of double blind placebo-controlled clinical trials utilizing a RF transmission device (Diapulse) suggest that this ancillary treatment device significantly reduces wound healing time for chronic pressure ulcers as well as for surgical wounds.

While numerous high frequency devices using pulsed electromagnetic energy to stimulate tissue growth have been developed, none have effectively addressed the needs of patients and health care providers.

The device disclosed in U.S. Pat. No. 5,584,863 has high power requirements, requires numerous manual adjustments for effective operation, incorporates only a single applicator, fails to ensure constant, known and replicable treatment dosage outputs, and provides no confirmation that the applicator is properly located during treatment.

While the various and several prior art inventions, as described in the above referenced patents, produce electrical, magnetic or electromagnetic fields for treatment of tissue, virtually none of the prior art describes any credible cellular or physiological or molecular processes by which such energy fields specifically alter, induce or otherwise make happen an increase in cell growth, proliferation or density.

Additionally, none of the previous high frequency, high power devices utilizing pulsed electromagnetic energy output adequately addresses such practical design concerns as ease of use, simultaneous treatment of multiple wound sites on the same patient, dosage measurement, monitored dosage control and / or dosage compliance.

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