Magnetotherapy is one of the most commonly used physiotherapy procedures. This method has proved successful in some diseases as therapy with long-lasting therapeutic effect (e.g. in chronic pains of vertebrogenous aetiology or in degenerative joint diseases) even when other therapy methods have failed. Application of magnetotherapy must always be based on a thorough medical history and detailed examination of the patient.
It is suitable to take into account that the natural magnetic field of the Earth equals approximately 0.04 – 0.05 mT (0.4 – 0.5 Gauss). The BTL device works with magnetic fields, the intensity of which may be up to 1000 times higher. Therefore, the application requires particular caution, also with respect to the fact that man has no specific receptors for a magnetic field and therefore does not perceive it directly – unlike e.g. an electric current.
The latest findings about the physiological response of the body to the electromagnetic field imply the following effects of magnetotherapy:
• analgesic effect,
• antiphlogistic effect,
• trophic effect (acceleration of healing and growth),
• myorelaxation and spasmolytic effect,
• vasodilatation effect,
• antiedematous effect.
ANALGESIC EFFECT
The analgesic effect of magnetotherapy applies in most algesic states of muscular as well as articular aetiology. A detailed description of this effect is quite complicated; its physiological effects have been specified in recent years. According to these findings, the analgesic effect of magnetotherapy is accounted for by the increased secretion of endogenous opioids caused by the myorelaxation, antiphlogistic and antiedematous effect and maybe also the impact on presinaptic inhibition of nociceptive signals at the level of the medullary dorsal horns. The treatment should be combined with aimed pharmacotherapy, manual treatment and relaxation therapy, at least in the initial stage.
ANTIPHLOGISTIC EFFECT
This effect has not been convincingly explained so far, but recent studies agree on the following principle:
The antiphlogistic effect is induced by increased phagocytosis of neutrophils and the increased production of hyperoxide. This is followed by the induction of hyperoxide dismutase bound to endothelium, which all probably leads to a higher concentration of hydrogen peroxide in the exposed area. Owing to the fast that hyperoxide inhibits the activity of catalase, the hydrogen peroxide is not degraded and thus is able to destroy leucotriens, some of the strongest activators of phagocytosis. This mechanism also explains the initial controversial action of the magnetic field in sterile inflammations as well as in microbially induced inflammations. This effect also accounts for temporary impairment of rheumatic conditions during the first two or three exposures, when the inflammatory symptoms are intensified by increasingly produced hyperoxide.
Simultaneous medication and physical therapy is necessary; the patient must be monitored during the therapy and in case of longer negative reaction, the therapy must be stopped.
TROPHIC EFFECT
The magnetic field accelerates healing of the skeleton and soft tissues. It is caused by better blood circulation in the exposed area and by the irritation of cytoplasmatic membranes. This activates the metabolic chain, the key point of which is a change in the cAMP/cGMP ratio. The acceleration of healing, especially of the skeleton, is described in detail in the literature (Chvojka, 1993, 2000).
MYORELAXATION AND SPASMOLYTIC EFFECT
Increased blood circulation in the area improves the washing away of acidic metabolites which cause painful irritation. In the muscles exposed to the magnetic field there also proceeds increased activity of LDH (lactate dehydrogenase) and efflux of the Ca2+ ion from muscle cells.
VASODILATATION EFFECT
This effect is caused by the efflux of Ca2+ ions, which causes relaxation of the tonus of the vascular musculature and precapillary sphincters. Probably the n. vagus is also directly influenced and the increased metabolic activity of cells in the exposed area results in the creation of EDRF and prostacyclins.
ANTIEDEMATOUS EFFECT
This effect results from the two above-described effects – the antiphlogistic effect of the magnet and acceleration of healing and improved blood circulation.