GB2434539A

GB2434539A - Implanted pain relieving nerve stimulator with insertion wire acting as temporary power cable

Info

Publication number: GB2434539A
Application number: GB0601462A
Authority: GB
Inventors: Teodor Goroszeniuk
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-01-25
Filing date: 2006-01-25
Publication date: 2007-08-01
Also published as: GB2434547A; WO2007085822A1; GB0701405D0; GB0601462D0; GB2434547B

Abstract

A percutaneous stimulating device 10 comprises a self-contained permanent or long-term unit for neuromodulation in the management of chronic pain and for cosmetic applications in accordance with the invention. It comprises a stimulating zone 12 with one or more electrodes 14, and an integral control unit 16 electrically connected by means of suitable wires 18 to the stimulating zone. The control unit 16 is arranged to supply an electrical stimulating signal to the electrode(s) 14. The device is inserted into a patient though a stimulating needle by means of an insertion wire which may be used to pass a stimulating current to the device to locate it accurately. The stimulating needle and the insertion wire are subsequently withdrawn.

Description

IMPROVEMENTS IN AND RELATINu 10

PERIFUERAL NEUROSTIMULATION

This invention relates to devices for peripheral neurostimulation for the long-term management of chronic pain and fbr cosmetic applications, and in particular to such percutaneous devices. It also relates to a method for performing such neurostimulation.

Neuromodulation has been established in medical practise since the introduction of peripheral nerve stimulation in 1965 and spinal cord stimulation in 1967. At present some 100,000 units are now implanted in patients around the world (2004). The majority of the implants are carried out for spinal cord stimulation, and similar applications like retrograde, sacral roots or nerve stimulation. Irnplantahle percutaneous devices usually have several discrete elements: an electrode, connections or an extension and a power source. The power to an electrode can be supplied from an external battery by means of a radio frequency (RF) receiver or from internally implanted IPG battery unit.

The use of peripheral neuromodulation technique is expected to expand during this decade. However, the available existing systems are less than satisfactory as they are often quite large and they comprise several separate components. They generally require a surgical procedure to introduce them.

In my earlier patent application GB 2,407,272 I describe a percutaneous stimulating device f'or long-term peripheral neuromodulation in pain management and CosiTletic applications comprises a stimulating zone with one or more electrodes, and an integral control unit electrically connected to the electrode(s) and capable of supplying an electrical stimulating signal to the electrode(s). The device is formed of an inert material and hermetically sealed and of a substantially cylindrical form so dimensioned as to be suitable for insertion into a patient through a stimulating needle.

In accordance with the present invention, an insertion wire is attached to the outer end of the stimulating device and extends outwardly from the outer end of the stimulating needle is arranged so that in use it can he used to fine tune the positioning of the stimulating device once it has been inserted into the patent. The wire is arranged SO that once the device is located it can he disconnected from the device, which remains in place, and withdrawn fronî the patient with the stimulating needle.

The insertion wire may also optionally he used to provide an electrical contact with the stimulating device permitting the electrodes to be used to provide electrical stimulation so that the device can be accurately located before the insertion wire is withdrawn, leaving the stimulating device in place.

In practice, a skilled practitioner will use an external stimulating probe to locate the area where pain relief by electro-stimulation is to he applied. In some cases treatment may be possible by means of external stimulation alone by applying the stimulating signal externally SO that it passes through the skin to the affected area. In more severe cases the area is accurately located by means of a stimulating needle inserted through the skin. A signal is then applied through the tip of the needle to locate the region of the affected nerve or muscle.

In the present invention the signal may he applied directly by the stimulating device through an electrical connection provided by the insertion wire. The latter is stiff enough to allow it to be used as a means to push or move the device to the optimum stimulating location.

Where the insertion wire is used to provide the stimulating signal to the stimulating device during its location, it needs to he insulated to avoid the current from leaking to the surrounding tissue. The insertion wire can also comprise a pair of conductors so that the signal is applied through the electrodes which form part ol' the stimulating device; in a simpler form, the insertion wire will comprise a single conductor SO that the electrical reference is provided by means of a patch which is used to provide the reference contact for the stimulating needle.

The percutaneous introduction of such a permanent device for peripheral neuromodulation by means of the stimulating needle and located by means of' the insertion wire considerably simplifies the procedures on patients and allows them to be carried out by other than by invasive surgery A small incision may nevertheless he required to the withdrawal loop if one is provided. It also minimises any surgical trauma resulting from the insertion of this type of unit. The use of the insertion wire to move the stimulating device permits a level of accuracy in positioning the device hitherto difficult to achieve and thus greatly enhances the efficacy of the device and the resulting pain relief'.

The device is thus intended to remain in place permanently, or at least for many weeks or months which is made possible either by the use of suitable long-life batteries, or by means of a radio frequency (RF) signal to a transformer connected to the control unit which converts the signal to the required amplitude and frequency for the electrode(s). It is also possible to apply the RF output directly to control the electrodes and/or to provide the energy for the device, The diameter of the device will not be greater than 2mm and preferably 1.5mm, and ideally less than I.2mnî to permit its insertion through a stimulating needle. It will he less than 70mm long so that it can be inserted through a normal stimulating needle, and preferably less than 40mm, though for cosmetic applications shorter versions of less than 20mm or even as short as 6mm may he required. As electronic components become smaller even smaller versions may become feasible, and the cost of the device is likely to decrease significantly The preferred stimulation frequency range of the device is between 1 and 50Hz and optimally between 2 and 10Hz. This low frequency has a particularly beneficial efièct on the treatment of chronic pain. A current of between 0.15 and 15 mA and preferably between 2 and 10 mA is thund to be very successful. In general a square wave is used and the wave duration is typically from 0.5 to 1 rnsec though it may he shorter or as long as 10 or 12 msec.

As the device may fail, or otherwise need to he renioved it is conveniently be provided with a drawstring at the end opposite to the stimulating zone to enable it to he removed from a patient if required without the need for a surgical procedure, although a small incision may he necessary. The draw-string is ideally opaque to X-rays to facilitate its location.

A stimulating needle ready for percutaneous insertion into a patient is intended in practice to he supplied as an assembly with the insertion wire attached to the stimulating device already inside the needle and with all the necessary electrical connections.

The invention will now he described specifically by way of example with reference to the accompanying drawing marked Figure 1 which is a diagrammatic view of a percutaneous stimulating device in accordance with the invention in the process of being inserted into a patient.

A percutaneous stImulating device 10 for long term peripheral neuromodulation in pain management and cosmetic applications comprises a stimulating zone with one or more pairs of electrodes 12, and an integral control unit 14 electrically connected to the electrode(s) and capable of supplying an electrical stimulating signal to the electrode(s). The device is formed of an inert material and hermetically sealed and of a substantially cylindrical form so dimensioned as to be suitable for insertion into a patient through a stimulating needle 16.

A semi-rigid insertion wire 18 attached to the outer end of the device 10 and extending outwardly from the outer end of the stimulating needle 16 is arranged so that in use it can be used to fine tune the positioning of the stimulating device The wire 18 is formed so that once the device is located in a patient it can he disconnected from the device which remains in place. The wire 18 is then withdrawn with the needle. The entry point of the insertion wire into the stimulating device is self-sealing maintain a hermetic seal of the device.

The stimulating device 10 is a self-contained permanent or long-term unit for neuromodulation in the management of chronic pain and for cosmetic applications.

An integral control unit 19 with a power supply is built into the outer end of the stimulating device and is capable of supplying an electrical stimulating signal to the electrodes 14 over a prolonged period of many months.

The body of the device is generally cylindrical having a diameter of 1.2 to 1.5mm.

It is between 20 and 70mm in length depending on its intended application. For facial or cosmetic applications however it may be as short as 6mm.

In use, the stimulating needle 16 is electrically connected to an external locating stimulator 20 by a lead 22 which is supplied with the stimulating ready for connection to the locating stimulator 20. A patch 24 is also connected to the locating stimulator 20 by a wire 28 and stuck to the skin 30 of a patient to make an electrical contact as a reference. In most cases an external locating signal will have been used to provide an initial location of the area to he Lreaed.

The locating stimulator 20 is than set to provide a low-level signal to the stimulating needle 22 which is inserted into the patient. The patient feels a beneficial effect as the signal at the uninsulated end 32 of the needle nears the affected area. When practitioner is satisfied that the needle is suitably located, he introduces the stimulating device 10 by pushing it through the stimulating needle 16 by means of the insertion wire 18.

The stimulating device is then activated and the final adjustment of its location is made by means of the insertion wire 18 so that the electrodes 14 on the stimulating device are optimally placed to treat the pain.

The stimulating signal, during location of the stimulating device 10, can either be supplied from the locating stimulator 20 to the stimulating device through the insertion wire 18 and the patch 28 or by an external RF device (not shown).

The frequency and the intensity of the signal supplied to the tip 32 of the stimulating needle, or to the electrodes on the stimulating device can he adjusted on the stimulating locator 20 by standard means, from say 1 to 10 Hz and from 0.1 to l5mA as required to produce the optimum level of relief. Typically the signal is of a square waveform and has a duration of 0.5 to 1 msec of each cycle.

As the device has a finite life and sooner or later will need to he removed, it is provided with a draw-string 36 which is buried under the skin with the device. The draw-string has a loop 38 at its outer end and is opaque to X-rays so that it can he easily located to allow the device to be removed after making a small incision.

It is anticipated that as electronic components decrease in size it will he possible to manufacture the device in ever shorter lengths, viz, shorter than 20mm or even less than 10mm. Very small devices which may he no longer than 6mm lend themselves particularly to cosmetic treatments, and to Facial iiiipiaiits. Longer devices iiiay be used for areas where a larger area of treatment is required, such as wrists, shoulder or the hack.

The stimulating device 10 shown may incorporate a radio frequency (RF) receptor.

The RF receptor is arranged to receive a signal and its energy from an external unit.

not shown, to generate the signal in terms of its frequency and amplitude. Thus the signal applied to the electrodes may he adjusted or controlled by the patient or a practitioner by the external unit as required. The external unit may he carried by or strapped to the patient to facilitate prolonged treatment, although a five-minute session one to three times a day will generally provide satisfactory relief.

The percutaneous device is placed in its desired position by applying a suitable signal to a stimulating needle and preferably through the device itself. A specialist doctor or practitioner determines the area of implantation and the ranges of the stimulating frequency and current. Where there is au RF connection between the device and an external unit the patient has a greater choice of use of the device to provide relief. He will also he able to vary the frequency and current within the parameters preset by the specialist practitioner to obtain optimum relief.

Claims

Claims 1. A percutaneous stimulating device for long-term peripheral

neuromodulation in pain management and for cosmetic applications comprising a stimulating zone with one or more electrodes, and a control unit electrically connected to the electrode(s) and capable of supplying an electrical stimulating signal to the electrode(s), the device being formed of an inert material and hermetically sealed and of a substantially cylindrical form so dimensioned as to he suitable for insertion into a patient through a stimulating needle characlerised in that the device is provided with a removable insertion wire to enable it to be inserted percutaneously through the stimulating needle and its position to be adjusted.

2. A stimulating device as claimed in claim I in which the insertion wire is an electrical conductor, connected electrically to the device.

3. A stimulating device as claimed in claim 1 or 2 in which the insertion wire is electrically insulated along its length to prevent electrical contact with the patient's skin during insertion of the device.

4. A stimulating device as claimed in any preceding claim in which the insertion wire comprises twin conductors, each insulated from the other and making an electrical connection with the device.

5. A stimulating device as claimed in any preceding claim in which the connection with the device is arranged to close hermetically on removal of the insertion wire.

6. 6 A stimulating device as claimed in any preceding claim in which the device is provided with a draw-string to enable it to be removed at the end of its useful life.

7 A stimulating device as claimed in claim 6 in which the draw-string is of a material that is opaque to X-rays to allow it to he easily detected under the skin when in use.

8. A stimulating device as claimed in any preceding claim whose diameter is not greater than 1. 5mm, and preferably less than 1.2mm.

9. A stimulating device as claimed in any preceding claim in which stimulation frequency range is between 1 and 20Hz.

10. A stimulating device as claimed in any preceding claim in which the stimulating current is between 2 and 2OmA.

1]. A stimulating device as claimed in any preceding claim in which the control unit in the device is arranged to receive a radio frequency (RF) signal from an external controller and to apply it in the required amplitude and frequency to the electrode(s).

12. A stimulating device as claimed in claim 6 in which the external controller provides energy by means of the RF signal to a transformer in the power supply part of the device or the controller.

13. A stimulating device as claimed in any preceding claim in which the device is supplied within a stimulating needle ready for insertion into a patient without the need for a surgical procedure.

14. A stimulating device for long-term pain management and cosmetic applications by means of peripheral neuromodulation as claimed in any preceding claim and substantially as herein described with reference to any one or more of the accompanying drawings.

15. A method for long-term pain management and for cosmetic applications by means of percutaneous peripheral neuromodulation by inserting a neurostirnulation device comprising one or more pairs of electrodes and an integral electronic control unit capable of supplying an electrical stimulating signal to the electrode(s) through a stimulating needle and accurately locating the device mechanically by using a semi-rigid insertion wire io locate the device in an optimum position in the zone to he stimulated by the device.

16. A method for long-term pain management and cosmetic applications as claimed in claim 15 in which the stimulating signal to the device is passed through the insertion wire.

17. A method for long-term pain management and cosmetic applications by means of percutaneous peripheral neuromodulation as claimed in claim 15 or 16 in which the stimulation frequency applied by the device to the patient is in the range between 2 and 10Hz.

18. A method for long-term pain management and cosmetic applications by means of percutaneous peripheral neurornodulation as claimed in any of claims 15 tol7 in which the stimulation current applied by the device to the patient is in the range between 2 and lOmA.

19. A method for long-term pain management and cosmetic applications by means of percutaneous peripheral neuromodulation as claimed in any of claims 15 to 18 and substantially as herein described with reference to any one or more of the accompanying drawings.