GB2423020A

GB2423020A - Percutaneous electrical stimulation probe for pain relief

Info

Publication number: GB2423020A
Application number: GB0502982A
Authority: GB
Inventors: Susan Ramao-Duarte Daniels
Original assignee: Algotec Ltd
Current assignee: Algotec Ltd
Priority date: 2005-02-14
Filing date: 2005-02-14
Publication date: 2006-08-16
Also published as: GB0502982D0; GB2423022A; WO2006084635A2; WO2006084635A3; GB0517122D0

Abstract

The probe comprises an elongate conductive body, the probe having a connector 3 for attachment to a holder 7 and cable retainer 8, the holder and retained forming a handle 6, the cable 9 is connected to a signal generator via connector 10. The end 2 of the probe may comprise a sharp skin piercing tip 5 or a removable cannula (figs 5, 6) having a sharp tip may form a sleeve over the probe. The probe has a number of simulation delivery regions 4 defined by a lack of electrical insulator on the probe at those regions. The probe is able to provide hyperpolarization of A-Beta fibres.

Description

PERCUTANEOUS ELECTRICAL NERVE STIMULATION THERAPY

Field of the Invention

The present invention relates to the field of alleviating pain in patients through the use of electrical pulses. This invention in particular relates to an apparatus and a method for delivering electrical impulses to treat discrete areas of allodyrija arid hyperalgesia.

Background to the Invention

Chronic pain is a well known and world wide problem, in some instances chronic pain can be a debilitating disease. The persistence and intensity of chronic pain may be affected by enviroimiental and psychological factors and in some cases chronic pain cannot be alleviated by the known medical treatments. Common chronic pain complaints include, for example, headache, back pain, pain induced by other conditions *: :* IS such as cancer, arthritis, shingles and such like, neurogenic pain and psycogenic pain. S... * S

Research into the area of alleviating and in some case treating the symptom of chronic pain through the use of electrical pulses has resulted in methods of treatment that are S..

accepted by the medical community for example Transcutaneous Electrical Nerve : ** * 20 Stimulation (TENS) can be used to stimulate peripheral inhibitory fibres in patients with * S..

nociceptive pain where the pain messages travel from the periphery via C Fibres to Rexed Lamina 1 & 2 and from there via the spinal thalamic tract to terminate in the sensory cortex resulting in a reduction of pain to the affected body area. TENS involves the application of electrical pulses to the body via electrode pads disposed on the surface of the skin. The electrical pulses pass through the skin and stimulate nerves and nerve endings in body tissues under the skin in the region of the electrodes. This has proved to be effective in alleviating pain such as back pain and pain associated with pregnancy and child birth. However, in the case of peripheral neuropathic pain a subset of patients have increased pain in the presence of TENS therapy. Studies have shown that in this group of patients C fibre termination at Rexed Lamina 1 & 2 ceases as a result of peripheral nerve damage and is replaced at Rexed Lamina I & 2 by A beta fibres. In a patient with neuropathic pain the A beta fibres projecting into Rexed Lamina I & 2 cause an exaggerated nociceptive response to what are normally innocuous stimuli.

(.1 Neurosci 1996 Aug 15;16(76,):5189-95; Eur J NeuroscL 2002 JuI;16(2):J 75-85; JPhysiol (2003), 548.!, pp. 131-138).

In addition, TENS therapy can be expensive in terms of the amount of equipment used per patient which will vary depending on the size and location of the area(s) to be treated. As the treatment is a continuous therapy it is not possible to utilise the same piece of equipment with more than one patient during a course of treatment.

Another electrical nerve stimulation treatment is known as spinal cord stimulation (SCS) also known as dorsal column stimulation (DCS). This involves the application of electrical pulses directly to the spinal cord via the epidural space and cerebrospinal fluid. Electrodes may be surgically implanted close to the spinal cord, for example in is the epidural pace and even touching dura mater surrounding the spinal cord. This is * .*** acknowleged to he an effective method for providing pain relief However, implanting ***S the electrodes, for example by accessing the epidural space, requires significant invasive surgery. This procedure therefore caes with it the risk of infection and damage to the * spinal cord. SCS / DCS also tends to provide paresthesia in a relatively large region of : * * 20 the body, which is not always desirable. I...

Stereotact Funct Neurosurg. 1993;61(3):146-55 **...* * .1 Neurosurg. 1993Feb; 78(2):233-9 Pain in localised regions of the body and in particular parts of the trunk, cannot be successfully targeted using SCS.

Stereotact Fund Neurosurg. 1999; 73('1-4):126-30 A further electrical nerve stimulation treatment known as peripheral nerve stimulation (PNS) has also been developed. This involves the application of electrical pulses directly to major nerves extending away from the spinal cord, such as the sciatic nerve of the leg, which are generally known as "peripheral nerves". This can provide pain relief more localised than that of SCS. However, PNS still requires significant invasive surgery for the electrodes to be put in place. Indeed, as the precise location of the peripheral nerves varies from patient to patient, the surgeon may well need to cut away a significant amount of tissue to locate the desired nerve during electrode implantation.

TI-us can caiIse significant trauma and nerve damage to the patient and is clearly undesirable Spine. 2000 Aug 1;25'l5k1886-92

D

Electrodes for both SCS / DCS and PNS are usually implanted whilst the patient is either under general anaesthesia or heavily sedated. The implantation is therefore an Inpatient procedure and is expensive in terms of operating room time and bed occupancy. It also utilises resources such as fluoroscopic equipment, which have multiple other uses.

Therefore there is a need for a method of alleviating pain in discrete locations in patients through the use of electrical pulses that does not entail major surgery and can be a(lministered quickly, easily and cheaply.

* .* 1 * . S ** S Thject of the Invention *5** It is an object of the present invention to provide an improved method and apparatus lbr * the treatment of chronic pain in discrete areas through the use of electrical pulses.

: * 20 Summary of the Invention

Percutaneous Electrical Nerve Stimulation therapy (PENSt) is an invention which S.....

* allows percutaneous electrical stimulation of subcutaneous tissue regardless of the location of any major peripheral nerves via a specifically designed PENSt probe for inserting into subcutaneous tissue under the skin of a subject and for delivering an electrical stimulus to the subcutaneous tissue, the probe comprising: (i) an electrically conductive elongate body having a first free end, a second end and at least one stimulus delivery portion between the first and second ends for delivering the electrical stimulus into the subcutaneous tissue; the first end having a sharp tip for piercing the skin to allow for insertion into the subcutaneous tissue at least so far as to locate the stimulus delivery portion in the subcutaneous tissue; and (ii) A connector located at the second end for connecting the probe externally to the body of the subject to a means for providing electrical impulses and for transferring the electrical impulses to at least the stimulus delivery portion of the body and which is connected to a specifically designed PENSt NeuroStimulator adapted to generate electrical impulses having balanced biphasic form with negative loading pulse and electrical impulses having square form to deliver electrical impulses to treat discrete areas of allodynia and hyperalgesia. For example in post mastectomy pain, neuropathic chest wall pain, chronic post surgical pain, post surgical wound pain, complex regional pain syndrome, reflex sympathetic dystrophy, neuropathic head and/or neck pain and/or : facial pain, neuropathic foot pain, penile pain, scrotal pain, testicular pain, post inguinal I*. * hernia repair pain, neuropathic abdominal wall pain, neuropathic failed back surgery S...

syndrome (FBSS) pain, migraine pain, post traumatic cervical neuropathic pain, * 15 vulvadynia, coccydynia, mastectomy lymphedema and combinations thereof. S.

S * ,

: . It is suggested that PENS therapy causes hyperpolarisation of A-Beta Fibres in the **.**.

* presence of neuropathic pain thus blocking peripheral allodynia and hyperalgesia and thus causing significant regional pain reduction. In this respect, PENSt differs from the

prior art methods of pain relief for example by:

i an absence of pain is created as a result of hyperpolarisation of ABeta fibres ratherthan paresthesia; 2 It is not a permanently implanted device; and 3 it is not a continuously administered therapy.

Brief Description of the Drawings

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:- [There have been some changes so I have had the drawings renumbered] Figure Ia, 2a and 3a are front elevations of 50mm long probes in accordance with the present invention; Figure 1 b, 2b and 2c are front elevations of 100mm long probes in accordance with the present invention; Figure Ic, 2c and 3c are front elevations of 150mm long probes in accordance with the present invention; * Figure 4 is a detailed drawing of a connector 10 Figure 5 is a front elevation of a 100mm probe without the detachable cannula [this * *:*. could be in any size and is used in conjunction with a cannula 14. This is the device that can be re-inserted subcutaneously using 1) either different cannula attachments 8a, S..

: * 15 Sb or 8c depending on the size of the stimulation area or 2) different cannula * .. attachments where one would not want to pass the same cannula twice for fear of S..... * .

infection i.e. scalp/hair. A single treatment may require multiple positioning of the prohe/carmula and the removeable cannula system as in Figures 5 and 6 allow the device to remain sterile for each positioning. In Figures 1, 2 and 3 the cannula can not be detatched from the probe, it is one sealed unit] Figure ôa, 6b and 6c are front elevations of 100mm cannula in accordance with the present invention; [this could be in any length with the described configurations] Figure 7 is a schematic representation of an area to be treated in accordance with the present invention; Figure 8 is a schematic representation of a probe located in the target area; Figure 9 is a schematic representation of two probes located in the target area; and Figure 10 and I Oa is a perspective view of a PENSt NeuroStimulator in accordance with the present invention.

Detailed Description of the Drawings

With reference to the probe assembly units in Figures la, 2a, 3a, Ib, 2b, 3b, ic, 2c and 3c, where a probe I comprises an electrically conductive elongate body with a first end 2 arid a handle assembly 6 which retains a second end 3 and a stimulus delivery portion 4 between the first 2 and second 3 ends. In one embodiment the first end 2 of the probe :: I comprises a sharp tip 5 to assist in piercing the skin when inserting the probe I percutaneously into the target area 21 so that at least the stimulus delivery portion 4 is *: * located in the target area 21. The handle assembly 6 further comprises a probe retaining :. is portion 7 and a first cable-retaining portion 8. A cable 9 comprising a first end 9a and a : * second end 9b is connected to the probe 1 through its first end 9a, which is located in *..* * :: the cable retaining portion 8 of the handle 6. The second end 9b is retained in a connector 10. The connector 10 comprises a second cable- retaining portion 11 and a NeuroStirnulator engaging portion 12.

The probe 1 has an elongate body and is preferably substantially cylindrical in shape however it is aIso possible to have probes of different shapes for example a fork-shaped probe with a plurality of tines or a probe shaped in accordance with the topology of the nerves to be treated for example the probe may comprise at least one branch and the branch(es) may he curved and of different lengths and shapes. The probe(s) I is made from an electrical conductive material so that an electrical current can travel from the NeuroStjmulator 22 through the cable 2 and along the probe 1. It is desirable that the probe(s) I are substantially rigid so that they can be easily manipulated. An example of a suitable material is stainless steel it will be apparent to a person skilled in the art The length of the probe(s) I will vary depending on the area to be treated for example tbr a treatment area wherein the largest dimension is 6cm a 5cm long probe can be employed. Typically the length of the probe(s) 1 will be between 1cm to 25cm for example 3cm to 20cm, such as 5cm to 15cm. However, when the target area 21 is large it is possible to insert more than one probe 1 into the target area 21 to obtain the desired effect (see Figure 9). The NeuroStimulator can accommodate either 1 or 2 probes at the same time through probe connector port(s) 38. * * * * .

:::.:. The probe retaining portion 7 acts to securely retain the probe I in the handle assembly S...

6. Typically the probe retaining portion 7 comprises the connection assembly where the * strands from within the cable 9 connect to the probe 1. Desirably the probe retaining

S

IS portion 7 is constructed from a non-electrical conducting material such as a hard plastic * :: material. The probe retaining portion 7 abuts the first cable retaining portioi 8 to make up the handle assembly 6. The first cable retaining portion 8 is desirably constructed from a non-electrical conducting material such as a hard plastic material The first cable retaining portion 8 and the probe retaining portion 7 lie adjacently to make up the handle and connection assembly 6. Preferably the handle assembly 6 is substantially rigid [hard plastic] so that it can withstand the external forces applied to it when the probe I is inserted into the target area 21. Desirably the handle assembly 6 has a non- slip grip to assist the end user when inserting the probe. Typically the handle assembly 6 will he constructed so that it is easy to hold and manipulate the position of the probe 1.

The cable 2 connects the probe I to a NeuroStjmulator 22 (see Figures 10 and 1 Oa).

The second end of the cable 9b is housed in the second cable retaining portion 11 where the conductive strands 9c running through the cable 2 are connected to the pins I 2b in the NeuroStimulator engaging portion 12 as in Figure 4. The pins 12b in the NeuroStimulator engaging portion 12 mate with the holes in the probe connector port(s) 38 of the NeuroStjmulator 22. To further secure the attachment of the NeuroStimulator engaging portion 12 to the probe connector port(s) 38 there is a snap lock mechanism l2a built into the NeuroStjmulator engaging portion 12 The second cable retaining portion 11 is desirably constructed from a non-electrical conducting material such as a hard plastic material. Typically, the cable 2 is approximately 2m to 0.5m long such as : [Sn-i to 0.7rn long for example l.2m to Im long to facilitate maintaining a sterile field at the patient while being connected to the NeuroStimulator 22 through the NeuroStirnulator engaging portion 12. The NeuroStimulator engaging portion 12 is preferably a plug wherein the external surface comprises a non-electrical conducting : * material such as a hard plastics material and the internal dimensions of the * NeuroStimulator engaging portion 12 arc configured to mate with the corresponding area of the NeuroStimulator 22 for example like a plug and socket. The interior of the NeuroStimulator engaging portion 12 comprises an electrical conducting means so that the electricity can be transferred from the NeuroStimulator 22 to the probe I. The exterior of the NeuroStimulator engaging portion 12 includes a "snap-lock" type mechanism l2a which secures the NeuroStimulator engaging portion 12 into the probe connector port(s) 38. The NeuroStimulator engaging portion 12 is adjacent to the second cable engaging portion 11. {detail of 10 above] Figure 6 showing 6a, 6b and 6c illustrate a non-electrically conductive cannula 14 that has a first end (un-insulated) 16, a second end 17 (insulated in 6a and 6b, un-insulated in 6c) and at least one stimulus delivery portion 1 8 between the first 16 and second 17 ends. The first end 16 of the carmula 14 desirably has a sharp tip 19 to facilitate insertion of the cannula 14 percutaneously. The cannula body 15 is elongate (substantially cylindrical) and dimensioned so that it can be placed over the probe 13 show in Figure 5 (like a sleeve). Therefore the shape of the cannula 14 is intimately linked with the shape of the probe 13, for example if the probe 13 is fork shaped, the cannula 14 will also be fork shaped. The internal dimensions of the cannula 14 are Jo shaped to compliment the dimensions of the probe 13. The cannula 14 is constructed : from a conductive matenal such as stainless steel and is insulated in part, in 6a and 6b with a Teflon type material in example 6c the cannula 14 is not insulated at all and is thereby one long stimulus delivery area 18. The cannula body 15 comprises at least one stimulus delivery portion 18, whereby the stimulus delivery portion 18 is defined by the * 15 lack of insulation with a Teflon type material of the cannula 14. According to the * * present invention there may be one stimulus delivery portion 18 for example the embodiment of Figure 6b and 6c alternatively there may be a plurality of stimulus delivery portions 18 substantially extending along the length of the cannula 14 for example the embodiment of Figure 6a. In use the NeuroStimulator engaging portion 12 is inserted into the probe connector port(s) 38 of the NeuroStimulator 22 and an electrical current can be created by the NeuroStimulator 22 which will pass from the NeuroStimulator 22, along the cable 2 and through the probe 13 and the cannula 14.

l'he stimulus deliver portion 18 of the cannula 14 acts to transmit electrical current from the NeuroStjrnulator 22 to stimulate subcutaneous and cutaneous nerves and nerve ends m the tissue in the target area 21, no electrical impulse will pass through areas of the cannula 14 that. are insulated with a Teflon type material The length of the probe 1 or probe 13 and cannula 14 can vary and are typically in the s region of 10mm to 200mm long such as 25mm to 170mm long, for example 50mm to lSOmm long and the gauge in the region of 15 to 30 gauge, such as 18 to 25 gauge for example 20 to 22 gauge. The length and gauge of the probe 1 and probe 13 with cannula 14 will be selected by the end user and will correspond with the size of the area to he treated.

hi one embodiment of the present invention illustrated in Figures 1, 2 and 3 the cannula * * 4 : ::.: and probe 1, and cable 2 are permanently connected to form one disposable device. Sc's

Whereas in a further embodiment such as that illustrated in Figures 5 and 6, the cannula 14 is a separate sleeve which may be releasably attached to the probe 13. This embodiment allows the cannula 14 to be replaced in instances where it would not be * desirable to reintroduce the cannula 14 into the target area 21 such as when the treatment area is located on the scalp of a patient where the risk of transferring infection into the target area 21 is high. In the device of this embodiment the probe 13 is reusable only in that when covered by the cannula 14 it can be inserted into multiple treatment sites, each time with a new sterile cannula 14, in the same or different target areas 21 but always on the same patient as the probe 13 itself may not be sterilised.

In use, the probe I is introduced subcutaneously along a previously determined target area 21. The NeuroStimulator engaging portion 12 is connected to the NeuroStimulator 22 via the probe connector port(s) 38, the treatment parameters are selected and the NeuroStjmulator 22 set accordingly and the therapy is administered. The therapy may he adrnjnjster'ed a number of times.

Figures 10 and 1 Oa illustrate a specific embodiment of the front, base and side view of a s PENSt NeuroStirnulator 22 in which the control panel 24 is a membrane keypad which may be accessed intra operatively using a transparent sterile disposable cover much like Op-Site known by a person skilled in the art (not shown). The PENSt NeuroStimulator 22 may have a casing 23 with dimensions of approximately 240mm W x 200mm H x 50mm D with a stand 43 inset into the underside of the casing 23 so that the NeuroStjmulator 22 can be angled at approximately 45 degrees making the control : * a.. panel 24 easy to operate and monitor. Non slip padding 42 is built into the stand 43 to secure the NeuroStjmulator 22 in position while in use. On the side of the : NeuroStimulator 22 would be an inset ON/OFF switch 40 and a mains port 41 * : l The control panel 24 has digital display windows 25, 26, 27, 29 and 30 which display the treatment parameters which parameters are selected using the keypads 31, 32, 33, 35 * and 37 to customise the therapy to the indication being treated. The stastop key 36 initiates a treatment session and is backlit while a therapy is being administered. The test key 34 is backlit when the NeuroStimulator is performing a system integrity test.

The system mode digital display window 28 displays the current status of the NeuroStimulator 22, for example, while performing an integrity test it will display "Test Mode", while delivering a therapy it will display "In Use mode", when ready to begin a therapy it will display "Ready Mode" and while resetting to default it will display "- - The end user can select the wave form using the wave form selector keys 31, the duration of the therapy through the timer keys 35 (the default is 120 seconds and the time is increased or decreased in increments of 10 seconds), the voltage through the voltage adjusier keys 37 (the default is 2 Volts) and frequency through the Pulse Rate adjuster 33 keys (the default is 2Hz) and Pulse Width adjuster keys 32 A typical treatment session may include a first session with a specific set of parameters and a second session with a different set of parameter and a typical treatment would include a first session using one wave form and a second session using the other wave form so that a complete treatment session included stimulation using both wave forms.

Tn use, Therapy selection would include: (i) either a "balanced biphasic with negative leading pulse" and / or a "square : .*. wave form"; :::.:. (ii) apulscrateofeither2 5, 10,40, 5Oor7OHz; * S. S (iii) a duration of the therapy, normally from 60 to 600 seconds * (iv) a pulse width of either I.OmSec or 2.OmSec S..

S

: * (v) a voltage of 0.00 to 3.00 volts. Typically 2.00 volts. Adjusts in increments I...

of 0.1 volts S..... * .

In use, the target allodynic area 21 is mapped by using a combination of cotton wool stimuli to the affected area with a comparator normal body part and to the hyperalgesic area using pin prick stimuli in the same manner. This method will identif' the areas of greatest allodynia and hyperalgesia.

The area 21 is then covered with a transdermal local anaesthetic such as Emla and 30 minutes is allowed for local anaesthetic to take effect.

A suitable PENSt Probe(s) I or 13 with attached cannula 14 is selected based on the size of the identified target treatment area 21. Larger areas may require the use of 2 probes simultaneously as described in Figure 9. The probe(s) I or 13 with 14 is then placed on the skin over the target area 21 and the probe entry point (X in Figures 8) is marked such that stimulus deliver portions 4 or 18 fall within the target area 21 when the probe(s) 1 or 13 with 14 is inserted into the tissue up to 3 as in Figures 1, 2and 3 or 17 as in Figure 6.

The PENSt probe(s) I or 13 with 14 is introduced percutaneously at the marked entry point (X) and tunnelled subcutaneously along the centre of the previously mapped target area 21. * S* * . e S.. S S... * . S...

* : 1'he coimector assembly of a Diathermy Pad (standard item not shown) is connected to * the PENSt NeuroStimulator 22 via the return port 39 and then placed on the patients S..

S

: *. * is skin an appropriate distance from the treatment area 21. The cable 2 extending from the S..

probe(s) I or 13 with 14 is attached to the PENSt NeuroStimulator 22 through the a..... * S

NeuroStimulator engaging portion 12 and the probe connector port(s) 38 and the desired parameters are set to begin the therapy session. The Start Key 36 is disabled until the NeuroStimulator 22 has successfully performed a system integrity test.

Once the deired parameters have been selected and the probe(s) 1 or 13 with 14 is positioned, The test key 34 is pressed. The NeuroStimulator 22 perfonns a system integrity test to ensure a complete circuit, at this time the System Mode digital display window 28 will display "Test Mode" and all other keys are disabled. Once the test has been successfully completed (just a few seconds) the System Mode digital display window 28 will display "Ready Mode". If the test failes due to a broken circuit etc. the system mod&digital display window 28 will display "Test Failed" and all connections will have to he checked. The start key 36 will not be enabled until a successful test has been done completed prior to each new session. Pressing start/stop key 36 begins the therapy. Start/stop Key 36 will light up indicating therapy delivery and the System Mode digital display window 28 will display "In Use" and all treatment parameter keys are disabled. The Timer digital display window 29 will count down from the preset time to zero and then automatically stop. The backlight on Start/stop key 36 will go off when the timer display window 29 displays "000". The System Mode digital display window 28 will then briefly display "- - -" during which time all keys are disabled. It : will then display "Ready Mode". Pressing the start/stop key 36 at any time during therapy delivery will stop the therapy session. The System Mode window 28 will I...

display "Aborted" for a few seconds and then "Ready". An aborted therapy session can * not be re-started midway. A new session would be delivered. A few seconds after a S..

S

: * 15 therapy session has been completed the control panel 24 will reset to the default *...

settings.

S..... * *

Typically, therapy continues for a period of 2-10 minutes and uses a frequency in the range from 2Hz to 70Hz and a selected wave form, depending on the indication. Once the therapy has completed the probe(s) I or 13 with 14 is removed. A steristrip closes the needle entry point and the patient goes home. This therapy is repeated at intervals based on patient response.

The successful patient will report significant if not total pain relief for a period. This period varies from patient to patient and could be months, future treatment sessions are based on the outcome of the initial session.

Examples

The invention will he more clearly understood with reference to the following

Examples:

EXAMPLE I - Post Mastectomy Pain The most commonly cited theory of chronic postoperative pain in breast cancer patients is the intentional sacrificing of the intercostobrachial nerves. These sensory nerves exit through the muscles of the chest wall, and provide sensation predominantly to the *. S... shoulder and upper arm. Because these nerves usually run through the packet of lymph nodes in the armpit, they are commonly cut by the surgeon in the process of removing the lymph nodes. * * * S S S...

* : * Symptoms arc described as burning, tingling, itching, or frank lancinating pain. In a small percentage of patients, chronic pain results, and the painful symptoms persist. The symptoms may he present almost continually, or they may occur in response to changes in physical activity or temperature. They may also be exacerbated by physical contact with the affected area i.e. the surgical scar, chest wall, breast, axilla and or ipsilateral upper extremity.

The incidence of chronic pain syndromes following breast cancer treatment has been estimated to occur in 20-25% of patients undergoing axillary (armpit) dissection, with or without mastectomy. Additional fhctors linked to breast cancer-associated chronic pain syndromes include polyneuropathies caused by chemotherapy and radiation therapy, which may be additive to impairments caused by surgery.

It is well known that a percentage of post mastectomy patients present with areas of hyperalgesia and allodynia Pain. 1999 Oct;83(J):9J-5 A retrospective cohort study of post mastectomy pain syndrome. Cancer Practice Volume 7 Issue 2 Page 66 - March/April 1999 Risk Factors

for Pain After Mastectomy/Lumpectomy (REFERENCE?). I0

The treatment area The area of greatest hyperalgesia. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We is map out the areas of greatest hyperalgcsia and place the Probe in the middle of that *.S. - held. * ** * **

Current treatment options : . . Anti-inflammatory agents (e.g., ibuprofen, naproxen, and other NSA IDs), low doses of S...

20 antidepressant medications (e.g., Elavil, Pamelor, and the SSRI-class of drugs, including Zolofi) can often be very helpful, although these agents must be taken consistently for several weeks to attain the greatest benefit. Unfortunately, narcotics are relatively inefièctive against established chronic neuropathic pain, and the risk of narcotic (lependency is very high when used in this setting. Topical counterirritants, such as capsaicin and mentholated creams, are useful in some cases, although their overall efficacy has been rather poor in most studies. Patients with longstanding and severe chronic postoperative pain syndromes, and patients with RSD following surgery in particular, present a very difficult dilemma for both patient and physician. Many such patients eventually become dependent on ever-increasing doses of narcotics to control their symptoms, and occasionally with tragic results. For patients with these very refractory and debilitating chronic pain syndromes, a combination of interventions may provide at least some relief from symptoms. Thoracic sympathectomy may provide relief, although there are some significant risks involved with such procedures.

Intermittent or continuous injections of anaesthetic and/or corticosteroids into the space around the spinal cord may also be effective. Medication e.g. amitnptylene, gabapentin, carbamazepinc, clonodjne, opioids, a pain management program and cognitive behaviour therapy. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency * S. :: : of 21-iz although a therapeutic treatment range could vary from about 2Hz to about I..

701lz This procedure is non-invasive and inexpensive and would be used as either a S. S S diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients * * : i.e. responders where pain relief was good but did not extend beyond 2 weeks would be * : oftèred alternative treatment options. The PENSt procedure in this instance acts as the *5SSSI * diagnostic tool.

Our patients report 80% -100% pain relief EXAMPLE 2 - Neuropathic Chest Wall Pain

Description of the condition

Chronic pain post surgery or an existing medical condition i.e. infection, cystic fibrosis etc. causes pain and second respiratory function reduction The treatment area Area of greafest hyperalgesia. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We map s out the areas of greatest hyperalgesia and place the Probe in the middle of that field.

rent treatment options Medication e.g. amitriptylene, gabapentin, carbamazepine, clonodine, a pain management program and cognitive behaviour therapy. Opioids are not an option as may interfere with respiratory function * . * * S PEN St ***. * a S...

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency a. I of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a * I :. diagnostic tool or as a therapy in itself to be repeated at inteals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% -100% pain relief EXAMpLE 3 - Chronic Post Sur2ical Pain

Description 6f the condition

Pain which developed after a surgical procedure and is still present in excess of 2 months post surgery The treatment area Area of greatest hyperalgesia, normally associated with the scar of surgery, or the site of a drain used at surgery. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and io the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in the middle of that field. .

Current treatment options I. * Local Anaesthetic infiltration, local nerve blockade, arnitriptylene, gabapentin, *,* is carharnazepine, clonodine, a pain management program and cognitive behaviour therapy.

S PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 701lz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% -100% pain relief.

EXAMPLE 4 - Complex Regional Pain Syndrome (CRPS)/ Reflex Sympathetic ystrophy (RSD) Pcription of the condition Post traumatic sensory or mixed nerve neuropathic pain, post trauma / surgery I myocardial infarct.

JO Complex Regional Pain Syndrome (CRPS) is a chronic pain condition. A patient with * CRPS has pain as well as changes in blood flow, sweating, and swelling in the painful area. Sometimes the condition leads to changes in the skin, bones and other tissues. It I.., may also become hard for a patient with CRPS to move the painful body part. The patieiit's arms or legs arc usually involved, but CRPS may affect any part of the body, is such as the face or trunk. In some patients, many different areas of the body are * aflected. CRPS can be progressive. CRPS usually develops after an injury. The injury may be to the skin, bone, joints or tissue. This type of CRPS has been called reflex sympathetic dystrophy. CRPS can also develop after any type of injury to major nerves.

This type has been called causalgia. The injury that leads to CRPS may be only minor, and sometimes a patient cannot remember any injury or event that caused CRPS to start.

The treatment area The Probe is placed in the area of greatest hyperalgesia on the affected limb Current treatment oDtionS Anti-i nflamrnatory drugs, corticosteroids, antidepressants, anticonvulsants, calcitonin, or opioids. Patients may have to take several different drugs together to get the best pain relief Sympathetic nerve blocks - include stellate ganglion nerve blocks, lumbar sympathetic nerve blocks and Bier blocks. Phentolan-ijne infusion, thought to have a similar effect as a sympathetic nerve block Some patients with CRPS have good pain relief from sympathetic nerve blocks, but the pain relief does not last long. For these patients, doctors might suggest a sympathectomy (killing the sympathetic nerves leading to the painful body part, either by using surgery or chemicals). Some patients get longer pain relief after the sympathectomy, hut others : * * do not. Also, there is the slight chance that patients who get a sympathectomy for CRPS of the leg might develop a new pain syndrome, called post-sympathectomy syndrome.

I * * * * I,

* : Acupuncture, transcutaneous electrical nerve stimulation (TENS), spinal cord :* s stimulation, or dorsal column stimulation. Intraspinal infusion - morphine, can be given IS...

* in low doses through the catheter.

Physical and occupational therapists can help patients with CRPS begin a program of stretching, strengthening, and aerobic conditioning. The goal of this program is to help the patient get back range of motion, strength and motor control. Physical and occupational therapists might also try treatments like warm and cold baths, ultrasound, or electric stimulation.

"Desensitization" is another important treatment that can be used to help with allodynia the patient's painful skin is rubbed with different materials, starting with soft, light textures and proceeding to rough, irritating surfaces. Gradually, the painful skin gets used to the rough textures, until the patient can easily deal with the touch of clothing, bed sheets, towels, etc. PENSt Many RSD patients get significant pain relief from SCS although there are instances where discrete areas of hyperalgesia / allodynia persist. These patients would have both an SCS implant and PENSt therapy. * *. * * S ** .

*... Post SCS implant: S. S S A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency I..

of 2Hz although a therapeutic treatment range could vary from about 2Hz to about * 70Hz. This procedure is non-invasive and inexpensive and would be used as either a S..... * S

diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% - 100% pain relief EXAMPLE 5- Neuropathic Head, Neck and Facial Pain

Description of the condition

Hyperalgic / alloynic area on head or neck The treatment area Area of greatest hyperalgesia. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in the middle of that field.

: . t treatment options :::.:. The treatment / management of neuropathic pain is multidisciplinary and includes a psychological assessment that is often crucial in developing strategies for pain management. Psychological variables include distress, depression, expectations of : 15 treatment, motivation to improve, and background environmental factors. Drug regimens utilise tricyclic antidepressants, anticonvulsants, and topical applications of capsaicin lbr intraoral pain.

PEN St A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% -100% pain relief.

EXAMPLE 6- Neuropathic Foot Pain

Description of the condition

Discreet area of pain in a distribution of a sensory nerve in the foot The treatment area Area of greatest hypcralgesia. Our current method of mapping the allodynic area is to * ..

use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas ofeatest hyperalgesia and place the Probe in the middle of that field.

Current treatment options * * Medication e.g. amitriptylene, gabapentin, carbamazepine, clonodine, a pain management program and cognitive behaviour therapy. Sympathetic nerve block, local nerve block, SCS - max 50% pain relief PENSt Some patients get significant pain relief from SCS although there are many instances where discrete areas of hyperalgesia / allodynia persist. These patients would have both an SCS implant and PENSt therapy. In patients where the treatment area is discrete only PENSt therapy would be used.

Pre or Post SS implant: A treatment session is about 2 to about 1 0 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccesf1.il patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acting as the diagnostic tool.

Our patients report 80% -100% pain relief * S S...

EXAMpLE 7 - Penile / Scrotal / Testicular Pain .

Description of the condition

Focal neuropathic pain at either site * S S...

**.s..

The treatment area The Probe is positioned subcutaneously over the inguinal canal Current treatment options Medication e.g. amitriptylene, gabapentin, carbamazepine, clonodine, opioids, a pain management program and cognitive behaviour therapy. Nerve Blocks. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% - 100% pain relief.

EXAMPLE 8- Post Inguinal Hernia Repair Pain cr1)tj2n of the condition * . e Focal neuropathic pain at the site * S The treatment area : : The Probe is positioned subcutaneously over the inguinal canal Current treatment options Medication e.g. amitriptylene, gabapentin, carbamazepine, clonodine, opioids, a pain management program and cognitive behaviour therapy. Nerve Blocks. 21) PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to he repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% -100% pain relief.

EXAMPLE 9- Neuropathic Abdominal Wall pain Dçcritjon of the condition It has been proposed that cutaneous nerve roots can become injured where they pass through the abdominal wall, perhaps by the stretching or compression of the nerve root along its course through the abdominal fascia. In some instances, a tight belt or other poorly fitted clothing can cause nerve root irritation, especially in physically unfit persons with protuberant abdomens. Pain also can occur in or around the abdominal * wall where muscles insert on bones or cartilage. For example, the pain can occur where :::,. IS the rectus abdomjnjs muscles insert on the lower ribs or where the lower ribs connect through cartilage. The xiphoid cartilage is sometimes a specific focus of pain.

Most commonly, abdominal wall pain is related to cutaneous nerve root irritation or myofascial irritation. The pain can also result from structural conditions, such as localized endometrjosjs or rectus sheath haematoma, or from incisional or other abdominal wall hernias. If hernia or structural disease is excluded, injection of a local anaesthetic with or without a corticosteroid into the pain trigger point can be diagnostic and therapeutic.

Pain that is the same or increased when the abdominal wall is tensed generally indicates an origin in the abdominal wall.

The mechanism for the pain may involve the development of an area of hyperalgesia as s a result of myofascial stretch injury.

The treatment area Area of greatest hyperalgesia. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in the middle of that field.

Current treatment options S. * The trigger point for abdominal wall pain can be treated with injection of a small volume of local anaesthetic. Local Anaesthetic and Steroid for more permanent relief of * I :. pain, it is often useful to inject a mixture of local anaesthetic and corticosteroid. Steroids * I.e 50 * presumably reduce inflammation or result in the thinning of connective tissue around painful nerve roots. If the correct spot is injected, the pain should be relieved immediately, but it may return in a few hours when the effects of the lidocaine wear off.

Triaincinolone may take effect slowly over a day or two and then provide long-term relief More than one injection may be required, given the hitor-miss nature of this treatment. If reasonable care is taken, the risks associated with the injections should be minimal. Repeated injections or larger doses of the corticosteroid can cause thinning of the fascia and result in a hernia. For this reason, depot-type steroids should not be used in the fascia. A trial of acupuncture or other alternative treatment might be considered. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% -100% pain relief. e

EXAMPLE 10 - Neuropathic FBSS pain *. Descnption of the condition : is Neuropathic low back pain following back surgery e.g. post spinal fushion, discectomy S * The treatment area Area of greatest hyperalgesia. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in the middle of that field.

Current treatment options Epidurals, nerve blocks, medication e.g. amitriptylene, gahapentin, carbamazepine, clonodine, opioids, a pain management program and cognitive behaviour therapy medication, SCS, Intrathecal opioids are delivered via a fully implantable device and deliver very small amounts of prescribed medication such as morphine directly into the intrathecal space, which is a protective space containing spinal fluid which bathes the spinal cord. PENSt

Many patients get significant pain relief from SCS although there are instances where discrete areas of hyperalgesia / allodynia persist. These patients would have both an SCS system implanted and PENS therapy.

Pre or Post SCS implant: * .* a a * - :.* A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 50% - 80% pain relief

EXAMPLE ii- Migraine

Description of the condition

Recurring intense headaches preceded by a sensory warning sign (aura), such as flashes of light, blind spots or tingling in your arm or leg. Miaines are also often accompanied by other symptoms, such as nausea, vomiting and extreme sensitivity to light and sound.

Migraine pain can be excruciating and may incapacitate the sufferer for hours or even days.

The treatment area The area of greatest hyperalgesia in the occipital scalp. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, and the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in

the middle of that field.

.: : Current treatment options S..

Treatment of chronic migraine may include certain antidepressants, antiseizure medications or cardiovascular drugs. However, even with such treatment, migraines * may persist. Currently there is no cure. Medications can help reduce the frequency of * : 1 migraines and stop the pain once it has started. The right medicines combined with self- : : help remedies and changes in lifestyle. PENSt

Our patients report 80% - 100% pain relief EXAMPLE 12 - Post Traumatic Cervical Neuropathic Pain

Description of the condition

Cervical neuropathic pain in the area of discrete nerve distribution The treatment area Area of greatest hyperalgesia. Our current method of mapping the allodynic area is to use "cotton wool" stimulation of the affected area with a comparator normal body part, : and the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in the middle of that field. * *.* ** . * * p

Current treatment options * : :.* 15 Diagnostic facet joint block, nerve root block, dorsal root ganglion block, medication e.g. amitriptylene, gabapentin, carbamazepine, clonodine, opioids, a pain management program and cognitive behaviour therapy. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 7OFlz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% - 100% pain relief.

EXAMPLE 13- Vulvadynja

Description of the condition

Vulvadynia / Vestibuljtjs is pain or discomfort of the female genitalia or surrounding area. Complaints may be of pain, burning, stinging, irritation, itching, inflammation or rawness. The discomfort can be constant or intermittent. Some women will only have pain when pressure is applied to the area surrounding the entrance of the vagina or the vestibule area, caused by trauma, surgery, child birth. 0* a * *0 * a.

*. The treatment area * * * is The Probe is positioned subcutaneously over the inguinal canal *. .. * a

Current treatment options Avoidance of vulvar irritants, diet, use of oral and topical medicines, vulvar injections, and surgery although treatment of some aspects remains controversial. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool.

Our patients report 80% - 100% pain relief.

EXAMPLE 14- Coccydynja Pcription of the condition Pain in the area of the coccyx (tailbone) is called coccydynia or coccygodynia.

Coccydynia can be anything from discomfort to acute pain, varying between people and varying with time in any individual. The name describes a pattern of symptoms (pain brought on or aggravated by sitting), so it is really a collection of conditions which can have different causes and need different treatments. * * . * S. *S*

is Coccydynia can follow after falls, childbirth, repetitive strain or surgery. In some cases * S S..

* the cause is unknown. The pain can disappear by itself or with treatment, or it can continue for years, and may get worse. It is five times more common in women than men, probably because the female pelvis leaves the coccyx more exposed. It appears that in most cases the pain is caused by an unstable coccyx, which causes chronic inflammation.

The treatment area Area of greatest hyperalgesia. Our current method of mapping the allodynic area is to use cotton wool" stimulation of the affected area with a comparator normal body part, arid the hyperalgesic area using "pin prick" stimulation in the same manner. We map out the areas of greatest hyperalgesia and place the Probe in the middle of that field.

Current treatment options Standard treatment is injection of an antiinflammatory drug around the coccyx. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients i.e. responders where pain relief was good but did not extend beyond 2 weeks would be offered alternative treatment options. The PENSt procedure in this instance acts as the diagnostic tool. * a * S * a...

Our patients report 80% - 100% pain relief.

EXAMPLE 15 - Lymphedenja (post mastectomy)

Description of the condition

Whenever the normal drainage pattern in the lymph nodes is disturbed or damaged (often during surgery to remove the lymph nodes), swelling of the arm may occur.

Radiation and chemotherapy may also cause swelling of the arm. This swelling of the arm, caused by an abnormal collection of too much fluid, is called lymphedema.

When the lymph nodes under the arm have been removed, a woman is at higher risk of lyrnphedema. Lymphedema may occur immediately following surgery, or months or years later. Not every woman who has a mastectomy will experience lymphedema.

There are several types of lymphedema. The acute, temporary, and mild type of s lymphedema occurs within a few days after surgery and usually lasts a short period of time. The acute and more painful type of lymphedema can occur about 4 to 6 weeks following surgery. However, the most common type of lymphedcma is slow and painless and may occur 18 to 24 months after surgery.

The main symptom of lymphedema is swelling of the affected arm. The de-ce of .: :* swelling may vary. Some people may experience severe swelling (edema) - with the affCcted arm being several inches larger than the other arm, while others will experience a milder form of edema - with the affected arm being slightly larger than the other arm. In addition to swelling of the affected arm, the following are the most

common symptoms of lymphedema. However, each individual may experience symptoms * 15 differently.

Symptoms may include: * feeling of ftrllness or tightness in the affected arm * aching or pain in the affected arm * swelling in the hand (may be evidenced by rings that no longer fit) weakness in the affected arm The treatment area The area of greatest hyperalgesia in affected arm Current treatment options Treatment tbr lymphedema depends on the severity and extent of the condition.

Prevention and controlling lymphedema play an important role with this condition since there is flO cure. PENSt

A treatment session is about 2 to about 10 minutes of stimulation at a typical frequency of 2Hz although a therapeutic treatment range could vary from about 2Hz to about 70Hz. This procedure is non-invasive and inexpensive and would be used as either a diagnostic tool or as a therapy in itself to be repeated at intervals. Unsuccessful patients - .4 e. respondes where pain relief was good but did not extend beyond 2 weeks would be 44* offered alternative treatment options. The PENSt procedure in this instance acts as the : diagnostic tool. *4 * 4

4.:.,: 15 Our patients report 80% - 100% pain relief and a siificant reduction in swelling.

I&a:ê * . It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims

Claims I. A probe for inserting into subcutaneous tissue of a subject and

for delivering an electrical stimulus to the subcutaneous tissue, the probe comprising: (ii an electrically conductive elongate body having a first free end, a second end and at least one stimulus delivery portion between the first and second ends for delivering the electrical stimulus into the subcutaneous tissue; the first end having a sharp tip for piercing the skin to allow for insertion into the subcutaneous tissue at least so far as to locate the stimulus delivery portion in the subcutaneous tissue; and (ii) a connector located at the second end for connecting the probe externally to the body of the subject to a means for providing electrical impulses and for transferring the electrical impulses to at least the stimulus delivery portion of the body.

0
2 A probe for inserting into subcutaneous tissue of a subject and for delivering an * :1.. electrical stimulus to the subcutaneous tissue, the probe comprising: (i) an electrically conductive elongate body having a first free end, a second end and at least one stimulus delivery portion between the first and second ends for delivering the electrical stimulus into the * subcutaneous tissue; the first end having a sharp tip for piercing the skin to allow for insertion into the subcutaneous tissue at least so far as to locate the stimulus delivery portion in the subcutaneous tissue; and (ii) a connector located at the second end for connecting the probe externally to the body of the subject to a means for providing electrical impulses and for transferring the electrical impulses to at least the stimulus delivery portion of the body; and at least one non-electrically conductive portion being provided on the body to insulate tissue in contact with the non-electrically conductive portion from the electrical stimulus.
3. A probe as claimed in claim 1 or claim 2 further compnsing a plurality of non- electrically conductive portions spaced along the length of the probe between the first and second ends.
4 A probe as claimed in any one of the preceding claims further characterised in that the stimulus delivery portion is provided by at least two discrete portions of the body which are between insulated portions of the body which are for insulating tissue in contact with the body of the probe.
5. A probe as claimed in any one of the preceding claims wherein the stimulus delivering portion runs from the tip toward the second end for a distance greater than 0.4 cm from the tip and for a distance of at least 2 cm * *,
6. A probe as claimed in any one of the preceding claims wherein at least one non- electrically conductive portion is located at the second end. S...

.:
7. A probe for inserting into subcutaneous tissue of a subject and for delivering an electrical stimulus to the subcutaneous tissue, the probe comprising: (i) an electrically conductive elongate body having a first free end, a : :* 20 second end and at least one stimulus delivery portion between the $1 first and second ends for delivering the electrical stimulus into the subcutaneous tissue; (ii) a connector located at the second end for connecting the probe externally to the body of the subject to a means for providing electrical impulses and for transfernng the electrical impulses to at least the stimulus delivery portion of the body; and (iii) a sleeve forming a housing for overfitting the probe body and having a first free end with a sharp tip for piercing the skin to allow for insertion into the subcutaneous tissue and for transmitting the electrical stimulus to the tissue.
8. A probe as claimed in claim 7 wherein the sleeve is non-releasably attached to the probe.
9. A probe as claimed in claim 7 wherein the sleeve is releasably attached to the probe.
10. A probe as claimed in any one of claims 7 to claim 9 wherein the sleeve is non- electrically conductive and/or is provided with one or more openings to allow at least a portion of the conductive body to contact the tissue.
I I. A probe as claimed in any one of the preceding claims wherein at least one of the sleeve or body has a plurality of sharp tips.
12. A probe for delivering a subcutaneous electrical stimulus in a subject for hyperpolarizing A-Beta fibres optionally in the presence of allodynia and hyperalgesia.

IS * *

* S. S
13. An electrical generator for generating an output for electrical stimulation of * S * subcutaneous tissue and adapted to generate electrical pulses having at least one of a balanced biphasic with negative leading pulse and a square wave form. * a

: : 20
14. An electrical generator for generating an output for electrical stimulation of S.....

* subcutaneous tissue and adapted to generate electrical pulses having at least one of a balanced biphasic with negative leading pulse and a square wave form, the generator being adapted for connection to at least one probe for delivering the electrical stimulus.
1 5 An electrical generator for generating an output for electrical stimulation of subcutaneous tissue and adapted to generate electrical pulses having at least one of a balanced biphasic with negative leading pulse and a square wave form wherein the pulse rate is selected from 0.5 to 80 Hz, the generator being adapted for connection to at least one probe for delivering the electrical stimulus.
16 An electrical generator for generating an output for electrical stimulation of subcutaneous tissue and adapted to generate electncal pulses having at least one of a balanced biphasic with negative leading pulse and a square wave form wherein the pulse rate is selected from 2, 5, 40, 50 or 70 Hz, the generator being adapted for connection to at least one probe for delivering the electrical stimulus.
1 7. An electrical generator for generating an output for electrical stimulation of subcutaneous tissue and adapted to generate electrical pulses having at least one of a balanced biphasic with negative leading pulse and a square wave form wherein the pulse width is about I.OmSec to about 2.OmSec, the generator being adapted tbr connection to at least one probe for delivering the electrical stimulus.
18. An electrical generator for generating an output for electrical stimulation of subcutaneous tissue and adapted to generate electrical pulses having at least one of a balanced biphasic with negative leading pulse and a square wave fbrm wherein the voltage up to about 3.00 volts, the generator being adapted fbr * . 15 connection to at least one probe for delivering the electrical stimulus. S...

*..:
19. An electrical stimulation device comprising a probe as claimed in any one of the * claims 1 to 13 and a generator as claimed in any one of claims 13 to 18 which : * * arc operably connected. S...

*S5SSS *
20. An electrical stimulation device comprising a probe for delivering a subcutaneous electrical stimulus in a subject operably couplable to a generator for generating an electronic stimulus the stimulus for hyperpolarising A-Beta fibres optionally in the presence of allodynia and hyperalgesia.
21 A method of alleviating pain in a human or animal body comprising the step of delivering percutaneously to subcutaneous tissue of the body via a probe, an electrical stimulus to treat pain.
22 A method of alleviating pain in a human or animal body comprising the step of delivering percutaneously to subcutaneous tissue of the body, an electrical stimulus that causes hyperpolarisation of A-Beta fibres.
23. A method according to claim 22 wherein the electrical stimulus is delivered by a probe inserted percutaneously.
24. A method according to claim 23 wherein the electrical stimulus is delivered by a probeinserted percutaneously and along a subcutaneous path.
25. A method according to any one of claims 21 to 24 wherein the probe is as claimed in any one of claims 1 to 12.
26. A method according to any one of claims 21 to 25 wherein the probe is inserted at an angle of less than about 45 to the body.
27. A method according to any one of claims 21 to 25 wherein the probe is inserted : *. at an angle of less than about 30 to the body.

:::.:. 15
28 A method according to any one of claims 21 to 25 wherein the probe is inserted at an angle of less than about 25 to the body.
29. A method according to any one of claims 21 to 28 wherein the probe comprises a stimulus delivery portion and the probe is inserted so that the stimulus delivery a..... . . . * . portion is located within the subcutaneous tissue.
30. A method according to any one of Claims 21 to 29 wherein the electrical stimulus is in the form of at least one of: a biphasic negative leading pulse and a square wave form pulse.
31. A method according to any one of Claims 21 to 30 wherein the electrical stimulus is pulsed at a rate of between about 1 and about 80 Hz.
32. A method according to anyone of Claims 21 to 30 wherein the electrical stimufus is pulsed at a rate of between about 2 and about 70 Hz.
33. A method according to any one of Claims 21 to 30 wherein the electrical stimulus is pulsed at a rate of about 5Hz.
34. A method according to any one of Claims 21 to 30 wherein the electrical stimufus is pulsed at a rate of about 10Hz.
35. A method according to any one of Claims 21 to 30 wherein the electrical stimulus is pulsed at a rate of about 40Hz.
36. A method according to any one of Claims 21 to 30 wherein the electrical stimulus is pulsed at a rate of about 50Hz.
37. A method according to any one of Claims 21 to 36 wherein the electrical stimulus is provided at a voltage of up to about 3.00 Volts. * IS * . *...
38. A method according to any one of Claims 21 to 37 wherein the electrical *** stimulus is provided for a time between about 1 and about 20 minutes.

I

* *
39. A method according to any one of Claims 21 to 37 wherein the electrical 1.:..: 20 stimulus is provided for a time between about I and about 10 minutes. * I
40. A method of reversibly inserting a probe into the subcutaneous tissue of a subject at an acute angle so that the probe tunnels under the skin comprising the steps (i) mapping the area to be treated; (ii) covering the area to be treated with a transdermal anaesthetic; (iii) selecting a probe of suitable dimensions for the area to be treated (iv) marking the location of entry of the probe; (v) percutaneously introducing the probe at the marked entry point and tunnelling the probe subcutaneously to the area to be treated; and removing the probe.
41. The method as claimed in claim 40, further comprising the steps of: (vi) connecting the probe to the electrical stimulation device as claimed in any one of claims 13 to 18; (vii) selecting the treatment parameters for the therapy; and (viii) initiating the electrical stimulus from the electrical stimulation S device.
42. The method as claimed in claim 40 or claim 41 wherein the step of mapping the area to be treated comprises pin prick or cotton wool stimulation.
43. The method as claimed in claim 40 to claim 42 wherein the probe can be inserted into an area of hyperalgesia or allodynia.
44. The method as claimed in claim 21 to claim 43 wherein the indications to be treated are selected from the group comprising: post mastectomy pain; * : :: :* neuropathic chest wall pain; chronic post surgical pain; post surgical wound pain complex regional pain syndrome; reflex sympathetic dystrophy; neuropathic * * head pain; neuropathic neck pain; neuropathic facial pain; neuropathic foot pain; penik pain; scrotal pain; testicular pain; post inguinal hernia repair pain; * * neuropathic abdominal wall pain; neuropathic failed back surgery syndrome :. : 20 pain; migraine; post traumatic cervical neuropathic pain; vulvadynia; * 1 coccydynia; post mastectomy lymphedema; and combinations thereof.
45. An apparatus comprising a probe for insertion percutaneously into subcutaneous tissue and a generator for operable connection to the probe for delivering an electric signal thereto adapted to early out a method as described above.
46. A probe as described herein and/or with reference to Figures 1 to 9 of the drawings.
47. An electrical generator as described herein and/or with reference to Figure 10 of the drawings.
48. A method of reversibly inserting a probe as described herein.
49. A method of alleviating pain as described herein and / or with reference to the

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