Electrotherapy

ELECTROTHERAPY, the application of electricity as a therapeutic factor. The favorable effect of electricity was noted even in antiquity: bathing in ponds inhabited by electric rays...

The invention of the static machine, the discoveries of Volta (1789), and Faraday (1831) gave a further impetus to the development of electrotherapy. The further development of electrical engineering, and recently also of radio engineering, has even more expanded the field of application of electricity in medicine. For electrotherapy, the following are currently used: 1) direct current, 2) alternating current, and 3) static electricity. The application of direct current is called galvanization (see). A distinction is made between general and local galvanization. General galvanization is used in the form of so-called hydroelectric baths (Fig. 1) and four-chamber baths according to Schnee (Fig. 2). In the first case, the patient is placed in a bathtub (porcelain or marble), one of the poles of the current source is placed at the head end, and the other at the foot end. The current intensity is 200–500 mA with a session duration of 10–30–40 minutes. The current in this case is closed through the water. Only an insignificant part of the current enters the patient, who is connected in parallel, the strength of which cannot be measured by this method. Eulenburger modified the technique: one of the poles is placed in the bath,

Figure 2.

Four-chamber bath. the other is applied directly to the patient (on the back or arms). However, due to the danger of grounding, these baths are currently used very rarely. Schnee's four-chamber baths and five-chamber baths have found much greater application. They consist of 4 (or 5) small (porcelain or china) bathtubs for the upper and lower extremities (and the pelvic girdle). The bathtubs are filled with warm water, into which carbon electrodes connected to the poles of the current source are immersed. There is a special switch for changing polarity. The session lasts 30–60 minutes. The current intensity is from 10 to 60 mA (according to the patient's sensation). The number of sessions is 15–30. Indications for general galvanization in the form of four-chamber baths are polyneuritis and polyarthritis of various etiologies, acro-paresthesias, and angioneuroses. In local galvanization, the current is passed through a limited area of the body. The electrodes should be positioned so that the bulk of the current passes through the affected area. To induce muscle contraction, intermittent galvanization is used, which consists in the alternate closing and opening of the current. If the interruptions are made at strictly defined intervals, galvanization is called rhythmic. Intermittent galvanization is carried out using a special electrode attached to a handle with a breaker (Fig. 3). For rhythmic galvanization, metronomes (Fig. 4) are used, which automatically turn the current on and off. The technique of the procedures is as follows: a passive electrode with an area of 300–400 cm² is placed on the chest or back of the patient, while the active one with a diameter of 1.5–2 cm is located at the motor point of the nerve or muscle (a motor point is understood as the place from which irritation of the corresponding muscle or nerve is caused at a minimum current intensity). Intermittent current is also used in the form of the so-called Leduc current, named after the author (Leduc) who first developed this method and proposed a special breaker for this purpose. The latter is a disk consisting of 4 metal segments separated from each other by ebonite interlayers (Fig. 5). The disk is driven by a motor. When the disk rotates, two carbon brushes slide along the sectors. The current closes at the moment when both brushes touch the same segment. The duration of current closures and openings and the number of interruptions are regulated by changing the distance between the brushes and the speed of rotation

Figure 3. Breaker handle.

of the motor. Usually, the number of interruptions is 100 per second, with a current intensity of 1–4 mA, with the ratio of the current passage time to the pause being 9:1. The voltage of the current source is 30–40 V. Leduc currents have a local anesthetic effect, and when passed through the brain can cause general anesthesia. This current has not found widespread application in therapeutic practice. Alternating currents used in electrotherapy include: 1) low-frequency alternating currents (faradic and sinusoidal currents) and 2) high-frequency alternating currents. The faradic current is obtained using an induction coil (see Du Bois-Reymond sledge apparatus) powered by a 4–12 V accumulator battery. The current induced in the outer winding when opening

Figure 4. Metronome breaker.

the current in the inner one—the so-called opening current—always has a higher voltage than the closing current, i.e., the current induced in the outer winding when the current in the inner one is closed. The electrode that is positive during the opening current is conventionally called the positive pole of the coil, and the one that is negative is considered the negative pole of the coil. When passing a faradic current through the organism, practically only the opening current can be considered effective (Fig. 6). The faradic current strongly acts on both sensory and motor nerves. A single opening induction shock, like the closure of a direct current, causes the contraction of a muscle or a group of muscles. If the irritations follow one another with a high frequency, a tetanic contraction of the muscle occurs. The frequency of irritations depends on the number of current interruptions in the primary coil. The latter is regulated by a special screw. In coils used for medical purposes, the number of interruptions ranges from 20 to 60 per second. Prolonged and frequent faradization, causing continuous muscle contraction, leads to fatigue and subsequently to atrophy of the latter. On the other H, rhythmic muscle contractions lead to enhanced nutrition and its subsequent hypertrophy. A distinction is made between general and local faradization. General faradization is used in the form of so-called bergoniization (see). Local faradization is currently used mainly in the form of rhythmized procedures, for which a metronome-breaker is introduced into the secondary circuit.

Figure 5. Leduc breaker.

The methodology and technique of local faradization are the same as in galvanization. Faradization is sometimes used in combination with galvanization (see Galvano-faradization). A sinusoidal current is an alternating periodic current. Its graphic curve is presented in the form of a sinusoid (Fig. 7). The source of sinusoidal current is the alternating current dynamos of municipal lighting installations with a voltage of 110–120 V. For therapy, it is necessary to reduce the voltage

Figure 6. Curve of faradic current. Figure 7. Graphic curve of sinusoidal current.

to 60–50 V using a step-down transformer. This current, due to its unfavorable effect on the cardiovascular system, especially at a number of periods around 50, is used very rarely. High-frequency alternating currents have found wide application in medicine. In some cases, high-voltage currents (tens and hundreds of thousands of volts) of small intensity (hundredths of an ampere) are used (see d'Arsonvalization), while in other cases the voltage is only hundreds of volts, but the current intensity reaches several amperes (see Diathermy). In recent years, therapeutic use has also been made of exposure to a high-frequency electric field (see Ultrashort waves). The application of static electricity for therapeutic purposes is called franklinization. As a source of static electricity, Holz-Wimshurst type machines are mainly used. The active part in them is glass or ebonite disks (from one to six pairs) rotated by a motor in opposite directions (Fig. 8). On the outer sides of the disks, strips of foil (up to 36 in number), so-called sections, are glued at an equal distance from each other, opposite which, along the diameter of both disks, two metal rods are installed mutually perpendicularly. Soft metal brushes are attached to both ends of the latter. When the disks rotate, the brushes slide along the metal sections, in which electricity is induced, which is then collected by needle combs onto metal spheres (with a diameter of not

Figure 8. Static machine.

in centimeters), called conductors. On one of the conductors, positive electricity accumulates, and on the other, negative electricity. The voltage provided by static machines reaches 25,000-100,000 V. To increase capacity, the machines are equipped with two Leyden jars. Static machines of the "Mercedes" type are also used, consisting of 3 disks—a stationary middle one and 2 outer ones rotating in the same direction. To protect the disks from dust and moisture, the machine is placed in a special cabinet with glass walls. Since even slight air humidity significantly reduces the machine's voltage, electric light bulbs or sulfuric acid are usually placed in the cabinet. The machine's disks become covered with fine metal dust from wearing sections and brushes, for which reason they require fairly frequent and thorough cleaning. The patient is subjected to the effects of static electricity (general Franklinization) or individual areas (local Franklinization). General Franklinization is performed as follows. On a wooden platform with legs made of well-insulating material (ebonite, glass), a metal plate is fixed, connected to one of the machine's conductors. Figure 9. Electrodes for local Franklinization. A chair is placed on the platform, with the patient sitting so that both legs are on the metal plate. Above the patient's head, a metal disk equipped with points and connected to the second conductor of the machine is placed, which moves in a vertical direction. The patient experiences a sensation of a light breeze. The session duration is 15-20 minutes. Sessions are daily or every other day. The course of treatment consists of 15-20 procedures. Local Franklinization is carried out using special electrodes (Fig. 9), in the form of a brush or a ball. The electrode, connected to one of the conductors, is brought close to the patient's body. With a brush electrode, the discharge of electricity from the points gives a sensation of a fairly strong breeze. With a spherical electrode, a spark jumps between the body and the electrode, the length of which depends on the distance between the body and the electrode and the magnitude of the voltage provided by the machine. Local Franklinization has a pronounced analgesic effect. Electrotherapy is indicated for a number of nervous diseases. Thus, in peripheral paralysis of the facial nerve, galvanization, ionogalvanization with iodine ion, diathermy, and rhythmic faradization or galvanization often give favorable results, and at times are the only method of therapeutic effect on the affected nerve. (When using rhythmic electrification, one must be very careful, and at the first signs of contracture, it is better to discontinue electrotherapy or use it in the form of ionogalvanization with iodine or diathermy.) In lesions of the nerves of the upper or lower limbs, galvanization, iodine-ionogalvanization, rhythmic faradization, or interrupted galvanization are used, and in cases where it is necessary to cause simultaneous contraction of many muscles, it is advisable to use bergonization. Electrotherapy is also widely used in neuralgias: galvanization, ionogalvanization with iodine and aconitine ions, diathermy, and local d'arsonvalization (preferably in the form of a small spark). The scope of application of electrotherapy in diseases of the central nervous system is very limited: diathermy and galvanization of affected segments of the spinal cord, and rhythmic faradization or galvanization of affected muscles in poliomyelitis; transverse ionogalvanization with iodine of the spinal cord area in tabes dorsalis; diathermy of the head in encephalitis; ionogalvanization according to the method of Bourguignon with calcium ions in vascular lesions of the brain and with iodine ions in sclerosis of cerebral vessels; general diathermy in progressive paralysis. General Franklinization, d'arsonvalization, and bergonization are indicated for functional diseases of the nervous system. Electrotherapy gives good results in some diseases of the autonomic nervous system: 4-chamber baths in acroparesthesias and diathermy in intermittent claudication. Electrotherapy in diseases of the cardiovascular system. In insufficiency of cardiac activity, galvano-ionotherapy with calcium chloride is used. In chronic insufficiency of blood flow to the heart, a course of general bergonization can be conducted. For painful sensations in the heart area, sometimes associated with spasm of the coronary vessels, local d'arsonvalization is indicated. In spasm of the coronary vessels with no sharply expressed degenerative changes in them, diathermy of medium strength (0.8-1.2 A) for 15-20 minutes gives successful results. Sometimes a favorable effect is observed when using general d'arsonvalization in the form of a cage in patients suffering from hypertension (of non-renal origin) with unpleasant subjective sensations. In local circulatory disorders in the area of the limbs, chamber baths with galvanic current are used. Local d'arsonvalization gives successful results in the treatment of varicose veins and hemorrhoidal piles.