Transcutaneous Electrical Nerve Stimulation (TENS) or Spinal Cord Stimulators (SCS) for Chronic Pain
What is it: It is the application of mild electrical current to the nerve fibers using electrodes, either internally (Spinal Cord Stimulator) or externally (TENS Unit). This stimulation is characterized by current, pulse width, and changes in frequency. The rationale to use electical nerve stimulation is based on the gate theory. The gate theory proposes that pain perception depends on the balance of large and small diameter nerve fiber acticivty and that an increase in large nerve fiber activity can potentially “close the gate” to inofrmation going to the brain from small pain fibers. When the gate is closed, the tramission of pain signals to the brain is blocked.
How effective is it?
There are conflicting reports on the effectiveness of TENS and SCS. Some doctors say both methods can be effective and some doctors feel that both methods can be ineffective. Some doctors tend to feel that implanting the stimulator (Spinal Cord Stimulator) is more effective then using the external stimulators (TENS). Wall & Sweet changed their opinion of application reporting that electrical nerve stimulation provided succesful relief of chronic pain directly through the skin alleviating the need for surgically implanted devices. I just recently read an aricle that stated the reverse.
I did seem to find one consensus of opinion that most all doctors seem to agree on is that you should do a trial stimulator before the surgically implanted one. Doctors feel that you should only get a surgically implanted stimulator, if the trial stimulator reduces your pain by 50%.
I have found through talking with individuals, that some have found both forms beneficial, TENS and SCS. For myself, external electric nerve stimulation has had a positive effect on my chronic pain. I chose not to do a surgical implant since I agree with Wall & Sweet, external is as effective as internal. You will have to draw your own conclusions. For more information on the risks and benefits of Spinal Cord Stimulators.
References: “Electrical Stimulation Therapy” by Jeffrey Larson, PT, ATC;
“Effectiveness of Transcutaneous Electrical Nerve Stimulation for Treatment of Hyperalgesia and Pain” Josimari M. DeSantana, PT, PhD, Deirdre M. Walsh, PT, PhD, Carol Vance, PT, MSc, Barbara A. Rakel, RN, PhD, and Kathleen A. Sluka, PT, PhD
“Spinal Cord Stimulation in Patients with Chronic Reflex Sympathetic Dystrophy”, Marius A. Kemler, M.D., Gerard A.M. Barendse, M.D., Maarten van Kleef, M.D., Ph.D., Henrica C.W. de Vet, Ph.D., Coen P.M. Rijks, P.T., Carina A. Furnée, Ph.D., and Frans A.J.M. van den Wildenberg, M.D., Ph.D.