Synonyms: electrotherapy, electro medicine, stimulation current therapy
Definition
The electrotreatment works with different electric currents, which have different biological effects in the body. It is used for therapeutic applications in medicine and physical therapy. Common to all procedures is that during the application direct or alternating currents flow through the body or body parts.
The corresponding voltages are supplied either via electrodes attached to the skin surface or via electrodes in a water bath. In special applications, implants for functional electrostimulation are implanted into the tissue. The different types and frequencies of current have different effects on the body.
On the one hand, the ions are increasingly transported in the body. Direct current causes a directed transport of the ions, alternating current leads to pendulum movements. In addition, the current depolarizes the cell membrane and thus triggers an action potential.
This leads to the contraction of a muscle cell or to the transmission of excitation to the nerve cell. Another effect of the current is the generation of heat in the tissue. This is caused by friction between the charge carriers and the treated tissue.
Direct current treatment is mainly used in the form of hydroelectric baths. Here, the directed current can be conducted through the entire body during a full bath (Stanger bath). The bathtubs for the Stanger bath have metal plates at the foot end and the sides.
These plates serve as positive pole (anode) and negative pole (cathode) and have different effects on the body. Some baths also have metal plates at the bottom of the tub and at the head end. However, these must have perforated plastic covers to comply with safety regulations.
The water temperature and current are adjusted to the patient’s well-being. The temperature for muscle tension and pain is usually set at 34°C and above, and in the case of flaccid muscles or paralysis it is more likely to be below 34°C. The current should tingle slightly on the skin, but not cause pain or discomfort.
As a rule, currents between 200 and 600 mA are used. In so-called cell baths the directed current is only directed to certain body regions, for example the arm or leg. By adding inonizing substances, the absorption of pharmaceuticals through the skin (percutaneously) can be achieved.
In iontophoresis, for example, pain-relieving, anti-inflammatory or circulation-promoting agents can be absorbed locally at the diseased body regions. Due to the strict laws and precautions involved in combining water and electricity, very strict regulations apply. A Stangerbad must comply with the Medical Devices Act and the Medical Devices Operator Ordinance, as well as the DIN standards.
The stimulation current therapy is carried out with low-frequency currents which are intended to stimulate the muscles. In this way, the muscle breakdown (muscle atrophy) that occurs after injuries or long illness can be counteracted. In stimulation current therapy, the electrodes are applied directly to the skin.
The contact resistance between skin and electrode is usually reduced by a gel. The current impulses lead to typical measurable changes in the muscles and selectively stimulate them. As a rule, the strength and duration of the pulses can be individually adjusted so that the current is not perceived as unpleasant.
Since sudden strong impulses are often perceived as disturbing, the stimulation current devices work with several average impulses per second. Specially adjusted training programs allow the devices to be used for strength training and to increase strength endurance. However, the effectiveness of this method for muscle building is controversial.
The study situation has not yet provided convincing results for muscle training. Nevertheless, it seems undisputed that stimulation current therapy can effectively stop or slow down muscle loss due to injuries or long-term immobility. Stimulation current therapy is contraindicated in all patients with heart problems or a pacemaker, as the current can trigger dangerous interactions with the pacemaker.
Diadynamic currents consist of two different current components: A low-frequency component and a direct current component. The diadynamic currents have a very strong analgesic effect, which increases with the direct current component. For this reason, the diadynamic currents are indicated for all painful diseases of the supporting and locomotor organs.Transcutaneous nerve stimulation is used to block the nerves that run to the spinal cord and the pain afferences that occur there.
The therapy is carried out with mono- or biphasic rectangular pulses (alternating current) of low frequency (2-4 Hz) or high frequency (80-100 Hz). The current sequences can be applied in the form of constant or interrupted pulse sequences. The electrical pulses are transmitted to the skin surface via various electrodes.
The electrodes are placed near the painful area. The stimulus itself should not cause any pain, but only leave a slight tingling sensation on the skin. The stimulation with high frequencies is applied directly above the aching dermatome, while the low frequencies are only applied if the after-effect of the high frequencies does not last long enough.
The treatment is intended to affect the pain-conducting sensitive nerve tracts in order to reduce or prevent pain transmission to the brain. The theory behind TENS says that on the one hand, the body’s own inhibition mechanisms are activated when the pain fibers in the spinal cord are irritated. On the other hand, the stimulation should stimulate other fibers descending to the spinal cord and increase the endorphin secretion in the brain.
Both mechanisms lead to a reduced sensation of pain. TENS is mainly used for chronic pain conditions of any kind. However, the treatment is contraindicated in pacemaker carriers, psychogenic or central syndromes.
Although there are some studies that do not confirm the effectiveness of TENS, in Germany the effectiveness is accepted and some treatments are paid for by health insurance companies. Since the frequency is too high at medium-frequency currents, the muscle cell can no longer respond to each impulse individually. This results in a reactive depolarization of the muscle cell and a resulting local muscle contraction without a sensitive annoyance.
Since the medium-frequency currents can thus effectively train the muscle contraction, they are often used for muscle atrophies (muscle breakdown) after serious injuries or long immobilization. In contrast to classical electrotherapy, high frequency therapy uses alternating electric fields in the frequency range between 4 and 30 kHz. High-frequency therapy generates electric or magnetic (short wave) or electromagnetic (decimeter wave, microwave) waves.
Their energy generates heat in the body and thus relaxes the treated muscles. With increasing frequency, the penetration depth of the currents decreases. For this reason, the short wave has the best penetration depth.
In contrast, the penetration depth of microwaves is only a few centimeters. Although the method is disputed and its effectiveness has not yet been proven by studies, high-frequency therapy is offered by numerous medical doctors in Germany. Due to the study situation, however, the costs of the treatment are not covered by health insurance.
Advocates of the therapy state that the treatment should be applied permanently three times a week for 30 minutes. Only then is there a possibility of permanent pain relief. The indication for radiofrequency therapy is very broad and is used mainly for back pain, degenerative joint diseases, diabetic polyneuropathy, migraine and headaches.
