Transcutaneous electrical nerve stimulation
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|Transcutaneous electrical nerve stimulation|
A four-lead TENS unit.
Transcutaneous electrical nerve stimulation (TENS) is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes. TENS by definition covers the complete range of transcutaneously applied currents used for nerve excitation although the term is often used with a more restrictive intent, namely to describe the kind of pulses produced by portable stimulators used to treat pain. The unit is usually connected to the skin using two or more electrodes. A typical battery-operated TENS unit is able to modulate pulse width, frequency and intensity. Generally TENS is applied at high frequency (>50 Hz) with an intensity below motor contraction (sensory intensity) or low frequency (<10 Hz) with an intensity that produces motor contraction. The benefit of TENS for pain is controversial.
Medical uses 
TENS is a non-invasive, low-risk nerve stimulation intended to reduce pain, both acute and chronic. Controversy exists as to its effectiveness in the treatment of chronic pain. One review from 2007 felt that the evidence supports a benefit in chronic musculoskeletal pain while another review from the Cochrane Collaboration in 2008 deemed the evidence of poor quality and thus no conclusions were possible regarding chronic pain. Results from a task force on neck pain, in 2008, found no clinically significant benefit to TENS for the treatment of neck pain when compared to placebo treatment. A 2010 review did not find evidence to support the use of TENS for chronic low back pain. There is tentative evidence that it may be useful for painful diabetic neuropathy. and knee osteoarthritis;
An adequate intensity of stimulation is necessary to achieve pain relief with TENS. An analysis of treatment fidelity (meaning that the delivery of TENS in a trial was in accordance with current clinical advice, such as using "a strong but comfortable sensation" and suitable, frequent treatment durations) showed that higher fidelity trials tended to have a positive outcome.
Labour pain 
A significant number of TENS machine brands have been targeted for use for labour pain, although a 1997 report of a study done by the University of Oxford said that TENS "has been shown not to be effective in postoperative and labour pain." Use is documented in the attached references: in obstetric care, particularly in labour;
Electrical stimulation for pain control was used in ancient Rome, 63 A.D. It was reported by Scribonius Largus that pain was relieved by standing on an electrical fish at the seashore. In the 16th through the 18th century various electrostatic devices were used for headache and other pains. Benjamin Franklin was a proponent of this method for pain relief. In the nineteenth century a device called the electreat, along with numerous other devices were used for pain control and cancer cures. Only the electreat survived into the twentieth century, but was not portable, and had limited control of the stimulus.
The first modern, patient-wearable TENS was patented in the United States in 1974. It was initially used for testing the tolerance of chronic pain patients to electrical stimulation before implantation of electrodes in the spinal cord dorsal column. The electrodes were attached to an implanted receiver, which received its power from an antenna worn on the surface of the skin. Although intended only for testing tolerance to electrical stimulation, many of the patients said they received so much relief from the TENS itself that they never returned for the implant.
A number of companies began manufacturing TENS units after the commercial success of the Medtronic device became known. The neurological division of Medtronic, founded by Don Maurer, Ed Schuck and Dr. Charles Ray, developed a number of applications for implanted electrical stimulation devices for treatment of epilepsy, Parkinson's disease, and other disorders of the nervous system.
Today many people confuse TENS with Electro Muscle Stimulation (EMS). EMS and TENS devices look similar, with both using long electric lead wires and electrodes. TENS is for blocking pain, where EMS is for stimulating muscles.
||This section contains instructions, advice, or how-to content. (March 2012)|
TENS electrodes should never be placed:
- Over the eyes due to the risk of increasing intraocular pressure
- On the front of the neck due to the risk of an acute hypotension (through a vasovagal reflex) or even a laryngospasm
- Through the chest using an anterior and posterior electrode positions, or other transthoracic applications understood as "across a thoracic diameter"; this does not preclude coplanar applications
- Internally, except for specific applications of dental, vaginal, and anal stimulation that employ specialized TENS units
- On broken skin areas or wounds, although it can be placed around wounds.
- Over a tumour/malignancy (based on in vitro experiments where electricity promotes cell growth)
- Directly over the spinal column
TENS should not be used across an artificial cardiac pacemaker (or other indwelling stimulator, including across its leads) due to risk of interference and failure of the implanted device. Serious accidents have been recorded in cases when this principle was not observed. A 2009 review in this area suggests that electrotherapy, including TENS, "are best avoided" in patients with pacemakers or implantable cardioverter-defibrillators (ICDs). They add that "there is no consensus and it may be possible to safely deliver these modalities in a proper setting with device and patient monitoring", and recommend further research. The review found several reports of ICDs administering inappropriate treatment due to interference with TENS devices, but notes that the reports on pacemakers are mixed: some non-programmable pacemakers were inhibited by TENS, but others were unaffected or auto-reprogrammed.
On areas of numb skin/decreased sensation TENS should be used with caution because it's likely less effective due to nerve damage. It may also cause skin irritation due to the inability to feel currents until they are too high. There's an unknown level of risk when placing electrodes over an infection (possible spreading due to muscle contractions), but cross contamination with the electrodes themselves is of greater concern. TENS should also be used with caution in people with epilepsy or pregnant women; do not use over area of the uterus as the effects of electrical stimulation over the developing fetus are not known.
See also 
- Action potential
- Bio-electric stimulation therapy
- Electrical muscle stimulation
- Electroacupuncture/percutaneous electrical nerve stimulation
- Electrotherapy (cosmetic)
- Failed back syndrome
- Neuromuscular dentistry
- Percutaneous tibial nerve stimulation
- Rebox electrotherapy
- Spinal stenosis
- Erotic electrostimulation
- Robetson et al., 4th ed.
- Robinson, Andrew J; Lynn Snyder-Mackler (2007-09-01). Clinical Electrophysiology: Electrotherapy and Electrophysiologic Testing (Third ed.). Lippincott Williams & Wilkins. ISBN 0781744849.
- Johnson M, Martinson, M (2006). "Efficacy of electrical nerve stimulation for chronic musculoskeletal pain: A meta-analysis of randomized controlled trials". Pain 130 (1): 157–165. doi:10.1016/j.pain.2007.02.007. PMID 17383095.
- Nnoaham, KE; Kumbang, J (2008 Jul 16). "Transcutaneous electrical nerve stimulation (TENS) for chronic pain.". Cochrane database of systematic reviews (Online) (3): CD003222. doi:10.1002/14651858.CD003222.pub2. PMID 18646088.
- Haldeman, Scott; Carroll, L; Cassidy, JD; Schubert, J; Nygren, A; Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders (15 February 2008). "The Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders: Executive Summary". Spine 33 (4S Supplement): S5–7. doi:10.1097/BRS.0b013e3181643f40. PMID 18204400.
- Dubinsky, RM; Miyasaki, J (2010 Jan 12). "Assessment: efficacy of transcutaneous electric nerve stimulation in the treatment of pain in neurologic disorders (an evidence-based review): report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.". Neurology 74 (2): 173–6. doi:10.1212/WNL.0b013e3181c918fc. PMID 20042705.
- Khadilkar, A; Odebiyi, DO; Brosseau, L; Wells, GA (2008 Oct 8). "Transcutaneous electrical nerve stimulation (TENS) versus placebo for chronic low-back pain.". Cochrane database of systematic reviews (Online) (4): CD003008. doi:10.1002/14651858.CD003008.pub3. PMID 18843638.
- Bjordal JM, Johnson MI, Ljunggreen AE (2003). "Transcutaneous electrical nerve stimulation (TENS) can reduce postoperative analgesic consumption. A meta-analysis with assessment of optimal treatment parameters for postoperative pain". Eur J Pain 7 (2): 181–8. doi:10.1016/S1090-3801(02)00098-8. PMID 12600800.
- Rakel B, Frantz R (Oct 2003). "Effectiveness of transcutaneous electrical nerve stimulation on postoperative pain with movement". J Pain 4 (8): 455–64. doi:10.1067/S1526-5900(03)00780-6. PMID 14622666.
- Bennett, M. I., Hughes, N. & Johnson, M. I. (2011) Methodological quality in randomised controlled trials of transcutaneous electric nerve stimulation for pain: Low fidelity may explain negative findings. Pain: 152 p. 1226-1232
- McQuay HJ, Moore RA, Eccleston C, Morley S, de C Williams AC (July 1997). "Systematic review of outpatient services for chronic pain control". Health Technology Assessment.
- van der Spank JT, Cambier DC, De Paepe HM, Danneels LA, Witvrouw EE, Beerens L (Nov 2000). "Pain relief in labour by transcutaneous electrical nerve stimulation (TENS)". Arch. Gynecol. Obstet. 264 (3): 131–6. doi:10.1007/s004040000099. PMID 11129512.
- Jensen JE, Conn RR, Hazelrigg G, Hewett JE (1985). "The use of transcutaneous neural stimulation and isokinetic testing in arthroscopic knee surgery". Am J Sports Med 13 (1): 27–33. doi:10.1177/036354658501300105. PMID 3872082.
- U.S. Patent 3,817,254
- Burton C (Jan 1974). "Instrumentation for dorsal column stimulator implantation". Surg Neurol 2 (1): 39–40. PMID 4810453.
- Watson, 12th ed., p. 266
- Alfred G. Bracciano, Physical Agent Modalities: Theory and Application for the Occupational Therapist, Edition 2, SLACK Incorporated, 2008, ISBN 1556426496 p. 232
- Roberston et al., 4th ed., p. 159
- Digby, G. C.; Daubney, M. E.; Baggs, J.; Campbell, D.; Simpson, C. S.; Redfearn, D. P.; Brennan, F. J.; Abdollah, H. et al. (2009). "Physiotherapy and cardiac rhythm devices: a review of the current scope of practice". Europace 11 (7): 850–859. doi:10.1093/europace/eup102. PMID 19411677.
- Roberston et al., 4th ed., p. 160
- Watson, 12th ed., p. 265
Books cited 
- Tim Watson, (2008). Electrotherapy: evidence-based practice (12th ed.). Elsevier Health Sciences. ISBN 0443101795.
- Robertson, Valma J.; Alex Ward, John Low, Ann Reed (2006). Electrotherapy Explained: Principles and Practice (Fourth ed.). Butterworth-Heinemann (Elsevier). ISBN 978-0-7506-8843-7.
Further reading 
- Cekmen N, Salman B, Keles Z, Aslan M, Akcabay M (Feb 2007). "Transcutaneous electrical nerve stimulation in the prevention of postoperative nausea and vomiting after elective laparoscopic cholecystectomy". J Clin Anesth 19 (1): 49–52. doi:10.1016/j.jclinane.2006.05.025. PMID 17321927.
- Gan LS, Prochazka A, Bornes TD, Denington AA, Chan KM (Mar 2007). "A new means of transcutaneous coupling for neural prostheses". IEEE Trans Biomed Eng 54 (3): 509–17. doi:10.1109/TBME.2006.886664. PMID 17355064.
- Ozawa M, Tsuchiyama K, Gomi R, Kurosaki F, Kawamoto Y, Aiba S (Dec 2006). "Neuroselective transcutaneous electric stimulation reveals body area-specific differences in itch perception". American Academy of Dermatology 55 (6): 996–1002. doi:10.1016/j.jaad.2006.08.032. PMID 17097397.
- Vrbová G, Hudlicka O, Schaefer Centofanti K (2008). Application of Muscle/Nerve Stimulation in Health and Disease. Springer. ISBN 978-1-4020-8232-0.
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