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Transcutaneous Electrical Nerve Stimulation (TENS)
Therapists should not be offering TENS treatments unless they are qualified and competent to do so.
What is TENS?
Transcutaneous Electrical Nerve Stimulation is a battery powered electrical unit which uses electrodes placed onto the skin to deliver electrical impulses to the nerve fibres which lie underneath the skin surface. It is used to provide pain relief by blocking pain signals to the brain via the spinal cord and peripheral nervous system, and also stimulates the production of endorphins, the body's own pain relieving mechanism (see The pain mechanism). Usually the electrodes are placed around the pain area or on acupressure points.
Side effects
Unlike medication, TENS does not produce side effects such as nausea or drowsiness. It can be administered while the client is going about normal activity and is not addictive. Occasionally the self-adhesive electrode patch sites can become irritated due to the adhesive but this can be overcome by using a different brand of patch.
Contraindications
TENS is unsuitable and should not be used in the following situations:
 | Over the anterior part of the neck. |
| Patients with cardiac problems |
| Patients with carotid sinus. TENS may cause bradycardia |
| Directly over any wound |
| Over the uterus of a pregnant woman, unless used for labour pain |
| Over the eye |
| Patients with pacemakers |
| Over poorly enervated areas |
| Non-compliant patients or those who are emotionally disturbed, have dementia, or low IQ |
(From Thompson et al.1991)
Precautions
| TENS devices should be used with caution where the cause of the pain has not been established. |
| TENS does not cure the underlying cause of pain. |
| TENS machines should be kept out of the reach of children. |
| The safety of TENS during pregnancy has not been established although it is widely used for pain relief during the early stages of labour. |
What can TENS be used for?
TENS can be used to treat most types of pain where the cause has been determined including:
· Arthritis · Back Pain · Bruising · Calf Strain · Dead Leg · Fibrositis · Finger Pain · Headaches · Migraines · Knee Pain · Lumbago · Muscle Stress · Neck Pain · Neuralgia · Osteo-arthritis · Period Pains · Post Herpatic Neuralgia · Pregnancy/Labour Pains · Rheumatism · Sciatica· Shoulder Pain · Sleeplessness · Spondylosis · Sports Injuries · Tennis Elbow · Tenosynovitis · Wrist Pain
How is it used?
The standard TENS treatment (convention or high frequency settings) is performed when the Pulse Rate is set to 60 pulses per second or more. The sensation produced will be a steady buzzing or tingling feeling between the electrodes. Because the TENS signal is perceived as stronger than the pain signal being produced by the body, it effectively blocks the pain signal from travelling along nerves to the brain. Most clients find that high-frequency treatments produce the quickest relief from pain, as well as providing several hours of relief after the treatment.
Treatment duration - 30 - 60 minutes, or continuous if required. Some units are portable and can be clipped to the belt while going about normal activities.
Low-frequency or burst type of treatment is produced when the Pulse Rate setting on the TENS unit is set manually below 10 pulses per second (or as with some units, at automatic burst mode. Low-frequency treatments produce visible muscle twitching often described as a tapping or pulsating sensation. In reaction to this type of stimulation the body releases endorphins (pain-killing chemicals produced naturally in the body). These endorphins act as a chemical nerve block to reduce pain by interrupting the pain signals along the nerves to the brain. Often this type of treatment can take longer to be effective but the results last longer.
Treatment duration - up to 30 minutes to be effective and treatment can be repeated during the same day.
Position of the electrodes
Best results are achieved by placing the electrodes directly over the pain site. With dual machines, additional electrodes can be positioned to surround the site. Electrodes can also be used to stimulate traditional acupressure points if required. Use the Body chart to record effective treatment sites and notes.
The Pain mechanism Tens Fact sheet
More information (with some help from G Gadsby)
Ahmed HE, Craig WF, White PF, Huber P (1998P) PENS therapy is a useful supplement to opioid analgesics for the management of pain secondary to bony metastasis in terminal cancer patients Clinical Journal of Pain Dec;14(4):320-3
Bechtel T. Fan PT (1985) When is TENS Effective and Practical for pain relief. How to put Electrical Stimulation to best use. The Journal of Musculosketetal Medicine 2(11):37-43
Belanger A Y (1985) Physiological Evidence for an Endogenous Opiate-Related Pain-Modulating System and its Relevance to TENS. A Review. Physiotherapy Canada 37(3):163-168
Bertoti D B (2000) Electrical stimulation: a reflection on current clinical practices Assist. Technology 12(1):21-32
Doody, S.B., Smith, C., & Webb, J. (1991). Nonpharmacologic interventions for pain management. Critical Care Nursing Clinics of North America, 3(1), 69-75
Fishbain, D.A., Chabal, C., Abbott, A., Heine, L.W., & Cutler, R. (1996). Transcutaneous electrical nerve stimulation (TENS) treatment outcomes in long-term users. Clinical Journal of Pain, 12(3), 201-214
Forster A, Palastanga N (1990) TENS. Calyton's Electrotherapy: Theory and Practice 103-107
Forster A. Palastanga N (1990) Pain Modulation. Clayton's Electrotherapy: Theory and Practice 100-110
Frampton (1996) TENS Clayton's Electrotherapy IOE 18:287-305
Gadsby G Articles on electroanalgesia
Hamza MA, White PF, Ahmed HE, Ghoname EA (1999) Effect of the frequency of transcutaneous electrical nerve stimulation on the postoperative opioid analgesic requirement and recovery profile Anesthesiology Nov;91(5):1232-8
Herman E. The Use of TENS in the Management of Chronic Pain Physiotherapy Canada 29(2):65-71.9.
Qi Journal's Interactive Acupuncture Chart
Jacobsson F, Himmelmann A, Bergbrant A, Svensson A, Mannheimer
C (2000)
The effect of transcutaneous electric nerve stimulation in patients with
therapy-resistant hypertension Journal of Human Hypertension
Dec;14(12):795-8
Jarmey C,. Tindall J (no date) Acupressure for Common Ailments Gaia Books Ltd
Johnson M I. Ashton C H. Thompson J W (1992) The Clinical use of TENS Journal of Orthopaedic Medicine 14(1):3-12
Johnson T,. R. McCracken (1984) TENS. Its Role in the Control of Chronic Pain. Arch Phys Med Rehabilitation 65:228-231
Kenner DJ (1994) Pain forum. Part 2. Neuropathic pain Aust Fam Physician Jul;23(7):1279-83
Mannheimer JS. Electrode Placements for TENS (1978) Physical Therapy 58(12):1455-1461
Martin LA, Hagen NA (1997) Neuropathic pain in cancer patients: mechanisms, syndromes, and clinical controversies Journal of Pain Symptom Management Aug;14(2):99-117
McQuay HJ, Moore RA, Eccleston C, Morley S, Williams AC (1997) Systematic review of outpatient services for chronic pain control : Health Technology Assess. 1(6):i-iv, 1-135
Melzack R. Vetere P. Finch L (1983) TENS for Low Back Pain. A comparison of TENS and Massage for pain and range of motion Physical Therapy 63(4):489-493
Mitchell, A. & Kafai, S. (1997). Patient education in TENS pain management. Professional Nurse, 12(11), 804-807.
Soric R.Devlin M (1985) TENS. Practical aspects and applications Postgraduate Medicine 78(4):101-107
Taylor, A.G., West, B.A., Simon, B., Skeleton, J., & Rowlingson. (1983). How effective is TENS for acute pain? American Journal of Nursing, 83, 1171-1174
Thompson, J.W., Johnson, M.I., & Ashton, C.H. (1991). An in-depth study of long-term use of TENS: Implications for clinical use of TENS. Pain, 44, 221-229
Wall P D (1985) The Discovery of TENS Physiotherapy 71 (8):348-350
Wong J. Rapson L (1983) TENS. Manual of TENS Therapy (no issue no.)