Electrotherapy

1. What are the physiologic effects of electrotherapy?
2. What are indications to electrotherapy?
3. What are contraindications to electrotherapy?
4. What is transcutaneous nerve stimulation (TENS)? Where are electrodes usually placed?
5. What are the proposed mechanisms of pain control via electrotherapy?
6. What is the gate-control theory?

Answers:
1. Increase in joint ROM, muscle group contraction, retards muscle atrophy, increases muscle strength, increases circulation, decreases muscles spasm, releases polypeptides and neurotransmitters, decreases spasticity, promotes wound healing, induces osteogenesis, inhibits pain fibers, drives medicated ions across skin.
2. Indications are pain management (msk pain, neurogenic pain, systemic pain), joint effusion, interstitial edema, muscle disuse atrophy, dermal ulcers and wounds, circulatory disorders, postherpetic neuralgia, arthritis, ROM.
3. Contraindications are circulatory impairment, stimulation over carotid sinus or heart, pregnancy, seizure disorder, fresh fracture, active hemorrhage, malignancy, decreased sensation, atrophic skin, inability to report pain, allergy to gel or pads.
4. TENS stimulates nerve fibers through a programmable device to apply an electrical signal through lead wires and electrodes on the skin. Electrodes are usually place over peripheral nerve distribution.
5. Placebo, gate-control theory, release of endogenous opioids.
6. The gate-control theory involves blocking pain signals at the spinal cord before they are transmitted to the thalamus. For example, a TENS stimulates large Ia afferent nerve fibers that stimulate the substantia gelatinosa in the dorsal horn of the spinal cord, that closes the gate on pain transmission to the thalamus.