Release time：2024-04-30 16:59
Source：
Page view：314
I. The skin pain threshold is significantly increased in the local area where medium frequency electrotherapy is applied, and it has a good analgesic effect clinically. In particular, the effect of low-frequency modulated medium frequency electricity is the most obvious. Its analgesic effect is divided into immediate analgesia and subsequent analgesia.
1. Immediate analgesia (direct analgesia). There are several hypotheses about the mechanism of immediate analgesia.
(1) Masking effect: Medium frequency current causes obvious tremor, and its impulse breaks into any link of the pain impulse transmission path, which can block or mask the conduction of pain stimulation, thereby achieving the purpose of analgesia or reducing pain.
(2) Cortical interference hypothesis: The electrical stimulation impulse and the pain impulse are transmitted to the cortical sensory area at the same time, causing interference in the central nervous system, thereby reducing or masking the pain sensation.
(3) Humoral mechanism of immediate analgesia: Currently, the endogenous morphine polypeptide theory is often used to explain it. Endogenous morphine-like polypeptide (abbreviated as OLS) is a polypeptide separated from the brain, pituitary gland, and intestine. It has morphine-like activity and is a natural neurotransmitter that has an analgesic effect in the body. The main ones related to analgesia are enkephalin (instant analgesia for 3-4 minutes) and endorphin (analgesia lasts for 3-4 hours). Medium-frequency current stimulation can activate endogenous morphine-like polypeptide neurons in the brain, causing the release of OLS and achieving an analgesic effect. The analgesic effect of these substances is 3-4 times stronger than that of morphine, and there are no side effects of morphine.
2. Subsequent analgesic (indirect analgesic) effect. It is currently believed that the analgesic effect of medium-frequency current treatment is mainly related to the fact that this current changes the local blood circulation, reduces edema between tissues and nerve fibers, reduces tension in tissues, relieves muscle spasms caused by ischemia, improves hypoxia, and promotes the removal of pathological pain-causing chemicals such as potassium ions, kinins, and amines, so as to achieve indirect analgesic effects.
II. Promoting blood circulation Medium-frequency current, especially low-frequency modulated medium-frequency current of 50-100Hz, has a significant effect of promoting local blood and lymphatic circulation, which can increase skin temperature, dilate arterioles and capillaries, and increase the number of open capillaries. Its mechanism of action:
1. Axon reflex: Medium-frequency current stimulates skin receptors, and impulses are transmitted to neurons on the one hand, and retrograde to the wall of arterioles through another branch of the same axon on the other hand, causing local vasodilation.
2. The role of vasoactive substances: Medium-frequency current stimulates sensory nerves, causing the nerves to release a small amount of "P" substances and acetylcholine and other vasoactive substances, causing vasodilation reactions.
3. Effects of muscle activity metabolites: The metabolites of muscle contraction, such as lactic acid, ADP, ATP, etc., all have obvious vasodilation effects.
4. Effects on autonomic nerves: The effect of medium-frequency current in promoting local blood circulation may be related to the inhibition of sympathetic nerves.
III. Exercise of skeletal muscle The medium-frequency current modulated by low frequency has a similar effect to low frequency current, which can cause skeletal muscle contraction. Therefore, it is often used to exercise skeletal muscle, and is more superior than low frequency current:
1. It has little stimulation to the sensory nerve endings of the skin and no electrolytic effect, which is more conducive to long-term treatment.
2. The human body has good tolerance to this current, and the current penetrates deep, especially for deep lesions.
IV. The effect of softening scars and loosening adhesions: Equal amplitude medium frequency current (audio current) has the effect of softening scars and loosening adhesions, and is widely used clinically.