he ability to be able to reduce pain and discomfort in certain chiropodial procedures, without resorting to local anaesthetics, has always been desirable; particularly with patients who have a low pain threshold. Despite having the training necessary to use local anaesthetics I have always been reluctant to utilise this facility unless in the environment of a proper operating theatre, with full aseptic procedures. The knowledge that a patient is experiencing acute pain should indicate to the chiropodist that a change of direction, instrument, or sensitivity in technique is required.

Using these criteria, I have been able to execute bilateral wedge excisions for many years, and following precise antiseptic and dressing procedures, have rarely experienced secondary infection or complications. So much so that the local hospital often send their patients to me for this procedure, who are on their lengthy waiting lists, for immediate relief, knowing that the worse pain the patient is likely to suffer is in my surgery, and not two hours later when a local anesthetic has worn off and seven bells of pain hits the unfortunate patient!

However, there are many occasions when a diminution of the pain without anaesthesia is advantageous, and for many years I have found a TENS unit extremely helpful. First of all it is necessary to understand the action of TENS, which stands for - "Transcutaneous Electrical Nerve Stimulation". It is a non-invasive method of managing acute pain without resorting to drugs, and is achieved by transmitting tiny electrical impulses via electrodes placed on the skin, to the adjacent nerve fibres which are responsible for carrying the sensations of touch, pain, warmth and pressure to the brain. Its analgesic effect is believed to be obtained by two actions:
 

1.      By blocking the pain via a 'gate' mechanism from being transmitted to the brain. By this action pain is not perceived.
 

2.      The stimulation of the body's own mechanism for suppressing pain by increasing the levels of the natural pain killing chemicals called endorphins in the vicinity of the pain source.

It is extremely safe to use, and has found wide acceptance in obstetrics, pain clinics, and in back, knee and other joint pain. Recently, with the GP's approval, I have obtained tremendous relief for an elderly lady suffering from post-shingles pain.

The only contra-indications are patients with a cardiac pacemaker, or may be pregnant, or who have a history of epilepsy. Over the last 16 years, since borrowing a TENS unit from an anaesthetist friend of mine in Nottingham, I have used about seven different models. They are now very small, about the size of a packet of cigarettes, as opposed to the first one which was about the size and weight of half a housebrick! Subjectively, the results have not varied in terms of effectiveness, so I decided to carry out a small evaluation on the model I currently use in my surgery, which is the Dentron Painaway. Although not the smallest or smartest of the various units available, none-the-less it does have the great advantage of having only one control knob, which is manipulated by the patient.

I also decided for the purposes of this evaluation to use it solely prior to treatment for onychocryptosis, and during the trial period of 18 months have treated 37 patients. The subjective results are to be seen in the accompanying table, and I hope it will encourage colleagues to think about this useful addition to their armamentarium, and perform procedures that they have been trained to treat, but have been reluctant to for fear of inducing too much pain in the patient.
 

Modus operandi

If the in-grown nail is infected, it should be left until the patient has completed a course of antibiotic treatment but, unfortunately, it may be necessary to extract a wedge of nail immediately to obtain instant relief and to break the trauma of the nail pressure and the inflammatory cycle it generates.

First, swab the nail with alcohol or other suitable skin-prep. The whole of this procedure must be performed under aseptic conditions as far as possible because of the risk of secondary infection. Allow the skin-prep to dry, and then attach the electrodes to the medial and lateral sides of the hallux. The patient then switches on the unit and rotates the control knob until a 'tingling' sensation is felt. Wait until this sensation subsides, and then continue to increase the intensity until roughly in the six o'clock position, and leave for about 2-3 minutes. I feel that it is very important that your voice conveys to the patient the positive effects that this procedure is going to have on them. Carry out the wedge excision very carefully, and on completion ask the patient to turn the unit off. At this stage the 'gate' opens to the brain, but as a high degree of analgesia is still maintained by the elevated endorphin levels, the patient will not suddenly suffer any discomfort.

Carry out your normal cleansing, antiseptic and dressing procedures, and if in any doubt, or the patient has a history of secondary infection, then contact the patient's GP for antibiotic cover. Of all the patients seen in this evaluation, none experienced a secondary infection, and only one returned a week later for further nail excision, which was not possible at the first visit due to hypergranulomatous tissue obstructing the view.

Key to pain score