GB2454481A - Dressing with integrated electrodes and control unit - Google Patents

Abstract

Apparatus provides electrical stimulation to tissue from a control unit and at least one electrode connected to a control unit supplying the stimulation current. A fixation element holds the at least one electrode against the tissue and also holds the control unit in a fixed position with respect to the tissue. The apparatus preferably has a central dressing portion 15 located in aperture 11 of a supporting substrate 2 and two electrodes 7, 6 arranged either side of the aperture and connected to the control unit 5 via conductor 8 formed upon insulator 10. Preferably the substrate is fastened to a patient's tissue via adhesive 3, and a wound may be positioned underneath the dressing portion.

Description

I

APPARATUS FOR ELECTRICAL-STIMULATION OF TISSUE AND METHOD

OF MANUFACTURING SAID APPARATUS

FIELD OF THE INVENTION

The present invention relates to an apparatus for treating tissue, in particular to an apparatus for regeneration and repair of damaged tissue by application of electrical current to the tissue via electrodes contained in the dressing. For example, the damaged tissue may be skin and the damage may be a wound, such as a laceration or an incision.

Alternatively, the damaged tissue may be tendons or ligaments and the damage caused by overuse or misuse. The present invention also relates to a method of manufacturing the aforesaid apparatus as an integrated dressing.

BACKGROUND OF THE INVENTION

Human or animal tissue is susceptible to many forms of damage. The damage can have many causes, including: non-complicated acute wounding, complicated chronic wounding, trauma, exercise related trauma and pathological damage.

An example of non-complicated acute wounding is a wound caused by surgery.

Complicated chronic wounding may include wounds such as diabetic and venous ulcers, pressure sores and bums. Trauma wounds may include lacerations, contusions, incisions and blunt trauma such as bullet injuries. Exercise related trauma may occur to muscles, tendons and ligaments as a result of overuse, misuse and abuse. Pathological damage may cause joint problems, such as osteo-arthritis and rheumatoid arthritis.

Repair of damaged tissue involves regeneration of tissue cells which occurs naturally as a result of repair mechanisms in the human or animal body. Often the natural repair of damaged tissue can be a lengthy process or does not occur at all as a result of the debilitating effects of infection or permanent damage to the tissue repair mechanisms.

The time taken to repair damaged tissue can cause many related problems, such as infection or re-infection of the damaged tissue, prolonged pain, temporary or permanent disability, scarring or aesthetic embarrassment for the injured person. For athletes and animals, such as horses, tissue damage prevents participation in training or competitions.

Dressings for promoting tissue repair have been known for many years. These dressings are coated with substances which are absorbed into the damaged tissue and actively encourage cellular regeneration and prevent infection. However, such dressings only provide a slight improvement in the speed of the healing process. In the case of serious trauma or large areas of wounding, such dressings can become ineffectual and, in some cases, create more damage, for example by preventing oxygen getting to the surface of the wound. In the case of muscle, ligament or tendon damage, such dressings have no therapeutic effect at all, except to act as a support to the damaged area whilst repair occurs naturally.

In recent years, electrical treatment of damaged tissue has become known as an effective method of treatment of damaged tissue. This method involves supplying electrical current to a treatment area (i.e. either directly to the external wound or to the surface of the skin near the damaged tissue). Electrodes are fixed to the treatment area and a current generating device is connected to the electrodes.

Some existing current generating devices for supplying current to electrodes fixed to a treatment area are described in international patent publication nos. 00/02622, 01/03768, 98/23326 and 98/40121 and United States patent no. 5,395,398. All of the current generating devices described in the aforementioned documents comprise a remote unit with attached electrodes. The electrodes must be fixed to the treatment area, typically with tape. Wires connect the electrodes to the current generating unit which is remote from the treatment area. Treatment with such devices requires specialist knowledge about the operation of the device and electrodes, including knowing where to locate the electrodes and how to connect them to the current generating device. This often necessitates frequent visits to clinics by a user of the device. Furthermore, there is the annoyance of having to carry a separate current generating unit. Generally, the user has to remain immobile whilst treatment is being carried out.

International patent publication no. 94/22529 describes an elastic housing with electrodes sewn into specific positions which can be worn by a user. When the housing is worn by a user, the electrodes are in the correct anatomic position for optimal treatment of the tissue which is to be treated. A current generating unit is fixed to the housing by insertion into a small pocket on the housing. The current generating unit is connected to the electrodes and supplies current to the electrodes with a waveform chosen from a number of different waveforms by the user using a control pad on the generating unit. The waveforms have constant amplitude and constant frequency.

One problem with the device of international patent publication no. 94/22529 is that it is difficult to obtain good conductivity between the electrode and the treatment area. Since the electrodes are sewn into the housing, they are not necessarily fixed to the treatment area appropriately even when the housing is correctly worn. The size and shape of the treatment area around which the housing is worn can vary from one user to another and even change shape or size over time. Furthermore, the treatment area itself can change its physical condition as it is repaired.

An integrated dressing comprising electrodes built-in to the dressing is described in UK patent no. 2406519 (incorporated herein by reference) and related overseas patents and co-pending applications. The dressing described in this patent includes electrodes integrated into the dressing. The control unit which is connected to the electrodes may or may not be integrated into the dressing. One advantage with this type of arrangement is that the electrodes are held in place securely near or adjacent to the tissue which is to be treated and do not need to be attached separately to the tissue. As the tissue changes shape, e.g. during healing or exercise, the electrodes remain held securely in place with the dressing. However, one problem with this type of dressing is that when the dressing is removed, the electrodes (and possibly the control unit if it is fixed to the dressing) are also removed and the dressing and electrodes (and possibly the control unit) must be disposed of together. Thus, even if the electrodes and control unit have not come to the end of their useful life (e.g. there is still battery power left in the control unit), they will be discarded along with the dressing. Disposal of the integrated dressing can be a problem if the dressing has to be disposed of in a hygienic way when the electrodes and control unit have to be recycled to comply with waste disposal regulations relating to electronic components. In addition, it is not possible to replace the electrodes whilst maintaining the dressing in place on the tissue being treated.

Accordingly, it is an aim of the present invention to provide an improved apparatus for treating damaged tissue that addresses all of the aforementioned problems.

SUMMARY OF THE INVENTION

The present invention is set out in the appendant claims.

In accordance with the aforementioned aims, there is provided, in a first aspect, apparatus for providing electrical stimulation to tissue, comprising: a control unit; at least one electrode connected to the control unit; and a fixation element adapted to hold the at least one electrode against the tissue and hold the control unit in a fixed position with respect to the tissue, wherein the control unit is configured to supply electrical current to the at least one electrode for stimulation of the tissue.

In this way, there is a single element which holds the control unit and electrodes which makes the apparatus very easy to manufacture and dispose of.

Preferably, the fixation element is a substrate having a first adhesive surface to be applied to the tissue, wherein the control unit and the at least one electrode are located on the first adhesive surface which is to be applied to the tissue.

In one embodiment of the present invention, the at least one electrode is fixed on the control unit.

In another embodiment of the present invention, the at least one electrode is connected to the control unit by a conductive element. The conductive element may be exposed and non-insulated.

Preferably, the conductive eiement is located between an insulator and the first adhesive surface. The insulator may extend the entire length of the conductive element.

An important feature of the invention, in one embodiment, is that the substrate has an aperture through which a dressing can be applied to the tissue such that the dressing or adhesive surface can be applied to and detached from the tissue independently of each other.

The substrate may have a second adhesive surface opposite the first adhesive surface, wherein the second adhesive surface is adapted for contact with a dressing and wherein the substrate has an aperture through which a contact surface of the dressing can protrude for contact with the tissue when the substrate is affixed to the dressing.

The apparatus of any one of the preceding claims, may comprise at least two electrodes which may disposed each side of the aperture so that electrical current can be supplied across an area which is to be treated.

Preferably, the substrate is rectangular in shape and the aperture is dimensioned to be larger than a conventional dressing.

In a second aspect of the present invention, there is a method of manufacturing the apparatus of any one of the preceding claims, comprising: placing a control unit and at least one electrode connected to the control unit on a first adhesive surface of a fixation element.

In a third aspect of the present invention, there is provided a method of manufacturing an integrated dressing for treatment of tissue via electrical stimulation, comprising: placing a control unit and at least one electrode connected to the control unit on a first adhesive surface of a fixation element; and applying a dressing to a second adhesive surface of the fixation element, wherein the substrate has a second adhesive surface opposite the first adhesive surface, and wherein the fixation element has an aperture through which a contact surface of the dressing can protrude when the substrate is affixed to the dressing.

Preferably, the method comprises: applying an insulator over a conductor which connects the at least one electrode to the control unit.

The insulator may be located between the tissue and the fixation element.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned invention is described with reference to the accompanying drawings in which:-Figure 1 is a perspective view of the apparatus according to one embodiment of the present invention; Figure 2 is an exploded perspective view of the apparatus of Figure 1; Figure 3 is a top plan view of the apparatus of Figure 1 used with a conventional tissue dressing according to a first particular embodiment of the invention; Figure 4 is perspective view of the apparatus of Figure 1 when applied to tissue; and Figure 5 is a perspective view of the apparatus of Figure 1 integrated with a conventional tissue dressing according to an alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to Figures 1 to 4, there is depicted an integrated apparatus 1 for applying to tissue. The apparatus 1 is disposable according to regulations relating to electronic waste. The apparatus 1 comprises an adhesive substrate 2 which is rectangular in shape, preferably the same shape as a conventional tissue dressing. The substrate has two opposing surfaces, namely: a first adhesive surface 3 and a second surface 4.

A control unit 5 substantially, which is identical in function and operation to the control unit described in UK patent no. 2406519, is disposed on the first adhesive surface 3.

Two electrodes, namely a first electrode 6 and second electrode 7 are also depicted. The first electrode 7 is connected and attached directly (by adhesive or other means) to the surface of the control unit on the opposite side of the control unit to the first adhesive surface 3. There is a first electrical connection between the control unit 5 and first electrode 6.

The first electrode 6 and control unit 5 may be located at or in proximity to a first edge of the substrate 2.

The second electrode 7 is affixed directly to the first adhesive surface 3 at a second edge 21 on an opposing side the substrate 2. The second electrode 7 is connected via a second electrical connection to the control unit 5. The second electrical connection is depicted in Figures 1 and 2 as a non-insulated wire conductor 8.

The control unit 5 contains electronic circuitry and a power supply which will be known to a person skilled in the art from UK patent no. 2406519. The electronic circuitry is connected to the electrodes 6, 7 and supplies electrical current in such a way that it passes between the two electrodes across the area which is to be treated. The electrical current stimulates the tissue cells to regenerate and improve healing of damaged tissue.

The electrical current is generally supplied at low voltages and low currents (e.g. less than 1 Volt and less than 1 microamp). The control circuit 5 includes a switch or other means for initiating its activation and an LED to indicate that it is supply electrical current to one or more of the electrodes. It will be appreciated that there could be any number of electrodes, more than two electrodes or one electrode which supplies current through the tissue to ground.

An insulator 9 is provided which is shaped and dimensioned to extend over the conductor 8 and adhere to the first adhesive surface 3. The insulator may be any type of electrically insulating material and may itself include a subsidiary adhesive surface 10 which is on the opposite surface to the surface which adheres to the substrate 2.

The substrate 2 has an aperture 11 which is shaped and dimensioned to conform to conventional dressing sizes, or to be slightly larger than a particular dressing 15 so that the apparatus I and dressing 15 can be removed from and affixed to tissue completely independently of each other. The aperture 11 may be any shape that conforms to conventional dressings, e.g. a square, rectangular or circular shape. The area of the aperture 11 may be in the range of 1 cm2 to any of2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 40, 50, 60, 70, 80 or 100 cm2 depending on the size of the area which is to be treated.

The substrate forms a border around the aperture and has a width which is the same or wider than the electrodes 6, 7 and control unit 5 which maybe 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20 cm depending on the size of the area which is to be treated.

Once all the components of the apparatus 1 have been assembled, the adhesive surface 2 of the substrate and subsidiary adhesive surface 10 of the insulator 9 may be covered with a removable protective layer (not shown) which can be removed prior to application of the apparatus 1 to tissue.

Application of the apparatus 1 to tissue is as follows. The tissue to be treated is exposed and the removable protective layer is removed from the substrate 2. The first adhesive surface 3 of the substrate 2 is then applied to the tissue around the area to be treated so that at least part of the area which is being treated is exposed through the aperture 11.

Pressure is applied to the second surface 4 to ensure that the apparatus 1 adheres to tissue.

The control unit 5 can then be switched on by operating a pressure switch through the substrate layer. Alternatively, the control unit 5 may switch on automatically by detecting the tissue temperature or by detecting a current pathway through the tissue between the electrodes 6 and 7.

Once the apparatus has been fixed to tissue, a dressing 15, such as a conventional wound dressing or other type of dressing may be inserted against the tissue through the aperture 11 and held in place by its own adhesive or other means, such as a bandage or surgical tape. This means that both the dressing 15 and apparatus 1 can be removed from the tissue completely independently of each other.

Figure 4 shows the arrangement when the dressing 15 and apparatus 1 have been applied to tissue 18.

It will be appreciated that the dressing could be applied to the tissue before applying the apparatus, or vice-a-versa.

In an alternative embodiment of the invention (not shown in the drawings), the first electrode 6 may be fixed directly to the first adhesive surface 3 separately from the control unit 5 and connected to the control unit 5 via a conductor in a similar way to the second electrode 7. Under this embodiment of the invention, the control unit 5 may be disposed on the second surface 4 (which may also comprise an adhesive) and the electrical connections to the electrodes 6 and 7 may reside substantially on the second surface 4 and connect to the electrodes at their surfaces which are in contact with the first adhesive surface 3 through the substrate 2.

In a further alternative embodiment of the invention depicted in Figure 5, the second surface 4 comprises an adhesive to which a dressing 15a which is larger than the aperture 11 could be applied and thus held in place on the tissue. In this embodiment, the dressing 1 5a protrudes through the aperture 11. This means that the apparatus I cannot be removed without removing the dressing iSa, but the dressing iSa could still be replaced independently form the apparatus 1 by pealing it away from the second surface 4. This arrangement also provides an effective way of manufacturing an integrated dressing comprising the apparatus 1 and a conventional pre-manufactured dressing.

It will of course be understood that the present invention has been described above purely by way of example and modifications of detail can be made within the scope of the invention.

Claims (15)

1. Apparatus for providing electrical stimulation to tissue, comprising: a control unit; at least one electrode connected to the control unit; and a fixation element adapted to hold the at least one electrode against the tissue and hold the control unit in a fixed position with respect to the tissue, wherein the control unit is configured to supply electrical current to the at least one electrode for stimulation of the tissue.

2. The apparatus of claim I, wherein the fixation element is a substrate having a first adhesive surface to be applied to the tissue, wherein the control unit and the at least one electrode are located on the first adhesive surface which is to be applied to the tissue.

3. The apparatus of any one of claims I to 4, wherein the at least one electrode is fixed on the control unit.

4. The apparatus of any one of claims 2 to 4, wherein the at least one electrode is connected to the control unit by a conductive element.

5. The apparatus of claim 4, wherein the conductive element is located on an insulator which itself is located on the first adhesive surface, such that the conductive element is contained between the insulator and the first adhesive surface.

6. The apparatus of claim 4 or claim 5, wherein the insulator extends the entire length of the conductive element.

7. The apparatus of any one of claims 2 to 6, wherein the substrate has an aperture through which a dressing can be applied to the tissue such that the dressing or adhesive surface can be applied to and detached from the tissue independently of each other.

8. The apparatus of any one of claims 2 to 6, wherein the substrate has a second adhesive surface opposite the first adhesive surface, wherein the second adhesive surface is adapted for contact with a dressing and wherein the substrate has an aperture through which a contact surface of the dressing can protrude for contact with the tissue when the substrate is affixed to the dressing.

9. The apparatus of any one of the preceding claims, wherein substrate is rectangular in shape and the aperture is dimensioned to be larger than a conventional dressing.

10. The apparatus of any one of the preceding claims comprising two electrodes.

11. A method of manufacturing the apparatus of any one of the preceding claims, comprising: placing a control unit and at least one electrode connected to the control unit on a first adhesive surface of a fixation element.

12. A method of manufacturing an integrated dressing for treatment of tissue via electrical stimulation, comprising: placing a control unit and at least one electrode connected to the control unit on a first adhesive surface of a fixation element; and applying a dressing to a second adhesive surface of the fixation element, wherein the substrate has a second adhesive surface opposite the first adhesive surface, and wherein the fixation element has an aperture through which a contact surface of the dressing can protrude when the substrate is affixed to the dressing.

13. The method of claim 12, further comprising: applying an insulator over a conductor which connects the at least one electrode to the control unit.

14. The method of claim 13, wherein the insulator is located between the tissue and the fixation element.

15. The apparatus of any one of claims 1 to 10, substantially as hereinbefore described with reference to the accompanying drawings.