TENS in a Pain Clinic

JENNIFER BENDING MCSP Physiotherapist in Charge of the Transcutaneous Electrical Nerve Stimulation Service, The National Hospital for Nervous Diseases, London

Key words: TENS, pain, pain clinic.

Summary: This article gives an overview of the use of transcutaneous electrical nerve stimulation (TENS) for neurological conditions in a pain clinic setting.

Biography: Jennifer Bending trained at The London Hospital. She worked for many years in the private sector before returning five years ago to work in the National Health Service. Currently she is studying part-time for a BSc(Hons) degree in remedial health sciences at Coventry Polytechnic.

THE National Hospital for Nervous Diseases is a postgraduate teaching hospital specialising in neurological conditions, and is a major centre for diagnosis and treatment. The pain clinic, under the care of a consultant anaesthetist, takes internal referrals only and offers the specialist techniques available for such problems to both in-patients and out-patients.

This article assumes that the reader has a working knowledge of transcutaneous electrical nerve stimulation (TENS) and concentrates rather on how it is used in the treatment of long-term pain.

The use of TENS has been part of the armoury of pain- relief techniques at The National Hospital since 1973, and over this period the number of patients treated per year has increased and now averages approximately 160 new patients per year. A core of knowledge helpful in dealing with such patients has been built up over this time. The service is run as a separate unit by a part-time physiotherapist with full- time secretarial help.

The main problem is the severity and intractable nature

Post - h e r pet ic Neuralgia. T4

of the pain and the psychological distress of the patients as they t ry t o cope and come t o terms with it. By the time patients are referred for TENS they have already tried a great variety of analgesics and other techniques, so that it is very much a treatment of last resort. Consequently the success rate is not so high as for acute conditions or in the out-patient department of a general hospital, but TENS does provide a useful adjunct t o other pain relief techniques and has the advantage of being non-invasive.

A secondary problem is the very large area from which the patients are drawn - from Aberdeen to the Isle of Wight - which makes regular follow-up more difficult, and means that the telephone is a major means of contact.

Initial Interview Patients who present for TENS generally have severe long-

standing pain which has often radically altered their lifestyle. It may have rendered them unable to continue working, or eliminated their social life. Consequently they often have unreasonable expectations of the benefits of TENS, or conversely feel that,it may not be worth trying as nothing seems t o work. A t the preliminary meeting it is therefore necessary to give a careful explanation of the part TENS may play in their pain relief programme. It should be stressed that it cannot cure their underlying problem, nor is it the magic answer t o their pain, but that it is a tool,'to be used as and when necessary and that with persistence, it could result in a useful amount of pain relief. They should be encouraged to adopt a positive attitude towards it and take responsibility for their own treatment plan.

A careful investigation of the painful area is then carried out and the details drawn on a chart (see figure). It is also important to ask patients for a description of their pain. They often find this very difficult, but can usually give some indication so that the different types of pain can be shown against the appropriate area. Patients are then asked to verify the diagram.

Subjective Experience CHECK LISTS

Always = Sometimes = _ _ _ _ _ Never = No underline

Hot Burning

Tingling Pricking Itching Scalding Sharp Cutting Boring Stabbing Flashing Shooting Aching Throbbing Pressing Cramping Pulling Wrenching

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The next step is to find out the effect the pain is having on their lives. Does it reduce walking ability, does it prevent sleeping, is it worse when they are sitting, and so on? The answers to such questions will be important in determining the most effective ways of using TENS.

Familiarity with the machine and confidence in its use are essential for good results. Clear explanations of all the knobs and their functions and a brief and simple explanation of the way TENS is thought t o work is therefore the next priority. This helps t o reduce the nervousness and apprehension natural in handling an electrical device.

Once the electrodes are in place, the patient is encouraged to turn on the machine, controlling the output knob himself. It is also of value t o suggest that he turns it up quite high until it feels strong and uncomfortable so that he knows what he is dealing with and understands the need t o be careful. He is then able to reduce the output to a comfortable level at which he will normally use it. He should also t ry all modes - continuous, burst and modulated - and learn the effect of altering the pulse width and the rate.

It should be explained to him that TENS does not help everybody. Some people derive no benefit at all, some are helped considerably and between the t w o extremes a number of people benefit enough for it to be worth while using. He should be encouraged to continue TENS for long enough. Very likely he will need to use it all day and in many cases during the night as well.

Advice about skin care should be given at the outset, as it may be that TENS will 6e used for a long period. If possible, electrodes should not be replaced in exactly the same position each day. It is advisable t o remove the electrodes daily, wash the skin carefully t o remove all traces of gum or gel and apply a suitable soothing cream if the skin shows signs of redness. A community nurse or local practice nurse may have to check on the skin condition if the patient is unable t o do this for himself.

An explanatory leaflet given to the patient to read at home allows him to concentrate on what is being said t o him in the clinic without worrying that he will forget vital points.

Before leaving the clinic, the machine is placed in a leather pouch with a flap fastened with Velcro which prevents the output knob from being inadvertently turned up by body movements. It is then securely fastened t o the belt.

Conditions Treated A wide variety of chronic pain conditions may be treated

by TENS, but each pain clinic patient has pain as his major problem, it has been present for months or years, it has been thoroughly investigated, and all other methods of pain relief have failed.

Many referrals have severe back pain resulting from neurological damage incurred by road traffic accidents, trauma at work or following surgery such as laminectomy. There is often associated leg pain and loss of sensation. Pain which is notoriously difficult to relieve can also occur following a myelogram or from post-surgical arachnoiditis.

Some patients present as a neurological problem, with pain that has not settled or has become worse, following routine surgery such as hysterectomy or a knee arthrodesis.

TENS is often tried for post-herpetic neuralgia. Burning pain and hyperaesthesia can be major problems, wi th the patient often unable t o bear the touch of clothes on his skin. This is a particularly disabling pain when it is facial or located in the eye. TENS is always worth trying and we have had roughly one-third success, with some patients continuing its use over a long period.

Conditions with a low success rate include perineal and vaginal pains, atypical facial pains and thalamic pain. Nevertheless, the occasional example does respond and in those cases, the patient often continues t o use TENS on a long-term basis.

For the back and leg pain associated with multiple sclerosis and minimal denervation syndrome, TENS can often provide useful long-term pain relief. This also applies to the generalised pain of post-viral syndrome. It should be pointed out t o these patients that while TENS relieves the pain, it does not help the fatigue and they should not, therefore, rush into unaccustomed exercise once the pain is lessened.

Phantom pain following amputation can often be eased by TENS, either by using it on the stump or on the remaining limb. Brachial plaxus lesions and peripheral nerve injuries present infrequently at The National Hospital, but are among the neurological conditions for which TENS may be used.

Other conditions are paraplegia and Guillain Barre syndrome. For these, help must be recruited for electrode application and skin checking, at home or in the intensive care unit. It is wise to instruct the nurses in the use of TENS, and t o encourage them t o t ry it on themselves, so that they appreciate how slowly t o increase the output and the optimum level of stimulation needed by the patient.

Patients are sometimes referred for TENS in an effort t o reduce the level of analgesics or opiates needed. It can also be requested for the relief of burning pain following neurological diseases.

Patients are allowed to decide for themselves whether they wish to continue using TENS after the initial trial period. They are generally reasonably clear how they feel about it at this stage Some regard even a slight benefit as being worth while and wish to continue, others feel they no longer need it and can cope without. Some regard it as an essential part of their life snd would be very unwilling t o part wi th it and some have abandoned it long before this stage. There are as many different attitudes towards TENS, and ways of using it, as there are people.

FOIIOW-UP Most important of all is a good follow-up service. At The

National Hospital this is most effectively done by regular telephone calls.

The patient must be secure in the knowledge of the therapist's continuing interest. Follow-up is particularly important in the first few weeks, when the patient is experimenting with the machine at home. Suggestions and reminders are welcomed and the call serves as an opportunity to discuss problems, and for the therapist to give alternative suggestions or further advice. Equally the patient must feel free to telephone the therapist if he feels the need, and he is given the names of people to contact, with the hospital telephone number and appropriate extensions. He is encouraged t o maintain contact until he feels secure in the method. The ease w i th which a patient can contact the therapist has been found to be of great benefit to those patients whose severe pain has led to depression or despair; help can be organised quickly. Routine regular contact is maintained subsequently. Follow-up is also available on a personal level either before or after clinic attendances with the consultant or during any TENS clinic.

General Points about the Use of TENS It is generally advisable to give a TENS consultation in the

presence of a partner, parent or friend, as very often their

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help will be needed for the application of the electrodes, and consequently they feel more confident.

Time and care are needed over the selection of a suitable machine for a particular patient. There is often difficulty in managing the knobs or holding the machine or being able to see the controls easily.

It is worth discussing the various electrode placements with the patient, but then starting with the simplest method. Once a patient is accustomed to its use, he can progress to trying alternative modes of stimulation or using a dual machine.

Giving the patient an outline drawing of a person showing the suggested electrode placement positions is a good aide memoire for home use.

General Advice on Use It is always worth while telling patients that results with

TENS are seldom fast or dramatic and that it takes perseverance to work out a suitable regime. They are encouraged to experiment sensibly within the guide lines worked out for them, but they must do this systematically. They can alter pulse widths, frequency, duration of use, etc, so long as they use each mode of treatment for long enough to be sure whether or not it is effective. They are encouraged to keep a record of what they have done, plus the results.

For some conditions, such as post-herpetic neuralgia, it is advisable to insist that stimulation be limited to half an hour at a time to begin with, as the pain may be aggravated by longer treatment.

Side-effects do not constitute a major problem with TENS, but can occur and patients should be advised not to persist with treatment if they are unhappy about what is happening. Rather they should telephone immediately for advice.

Patients should have explained to them that it is easier to relieve a pain as it starts, than to wait until it has reached a severe intensity and also that if they know what precipitates a pain, TENS should be used beforehand in an effort to stave it off.

Patients should be allowed to trust their own judgement

in electrode placement positions. They often know intuitively the most beneficial placements.

Finally, patients are assured that if they find TENS of benefit, they will be able to borrow a machine for as long as they find it helpful. An efficient loan system is thus essential, particularly when there are several hundred machines being issued in rotation.

Side-effects On the whole side-effects are not serious. Most commonly

encountered is an allergic skin reaction to the gel or fixing tape of the electrodes, but trying several alternative kinds of electrode minimises the problem.

Sometimes the pain can be exacerbated or spread to other areas, in which case the technique needs modification.

Headaches, nausea, oedema and faintness have all been reported and generally these act as contra-indications to continuing.

Conversely, some side-effects are advantageous, as in multiple sclerosis when relief of back pain is often associated with improvement in bladder function or relief of spasm.

Conclusion TENS as used in the pain clinic at The National Hospital

is only one of a series of techniques available but it has the merit of being non-invasive and simple to use. Although it is unlikely to give complete pain relief, it is worth while going to consideFable lengths to maximise its good effects. It can have a powerful psychological effect, in that patients feel that they have a means of controlling their own pain and it encourages them to be more positive in their attitude towards it. Often with good long-term follow-up, other techniques are not found necessary.

The pain relief obtained by using TENS does not always last as long as the patient would like. It can vary from a few weeks to a few months, although in some cases it continues for many months up to several years. Yet patients regard even a brief respite as valuable and all are glad to have had the opportunity to try it.

Incontinence - The Challenge This issue of Physiotherapy contains a series of articles on 'Pain and Stress' and there will be more on the same theme next month.

In 1983 a similar symposium was published on 'Incontinence', and the articles are still available reprinted in booklet form (f 1 including postage from the Journal Department). However, the time has come when some of the concepts in these papers need updating, and we should add new material reporting recent work on the subject.

We are therefore calling for papers on any aspect of incontinence to form a new symposium on the subject. In the first instance please send a summary of the article to the editor at 14 Bedford Row,

London WC1R 4ED, by June 30 at the latest, marking the envelope 'Symposium'.

The summaries will be considered individually and as a group, and if they fit well together the authors will be sent guide lines on presentation and asked t o complete their papers by the end of the summer. The articles will then be assessed in their complete form and processed for publication in the usual way.

Incontinence is a persistent challenge and physiotherapists have a significant part to play in its control so please let us know about your experience and expertise by formulating the summary for a paper as soon as possible.

Don't forget - No one will know about your work if you don't tell them. Don't leave your colleagues in the dark and allow patients to suffer unnecessarily from this depressing complaint.

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