1. INTRODUCTION TO DIATHERMY AND ITS THREE TYPES

According to a report of the French physiologist d'Arsonval, the physical therapy with electromagnetic (EM) energy began in the late 1800s. He noticed that alternating current at a frequency greater than 10KHz produced Joule's heat without evoking the pain or muscular contractions.

DIATHERMY

Light rays are electromagnetic (EM) waves with super excellent high frequencies. A frequency of EM wave becomes gradually higher, so its wave-length gradually shorter in order from electric waves →infrared rays →visible rays →ultraviolet rays →X-rays →and finally to gamma rays. The range of electromagnetic waves applied mainly for communication engineering i.e. the radio frequency portion of EM waves is called the electric wave. Diathermy is a therapy with the electric wave.

Electrosurgery (surgical diathermy) uses the medium radio wave and is called long wave diathermy (LWD). LWD at a frequency of 1000KHz by means of a spark-gap generator began in 1895 by Zeynek as a internal treatment named thermopenetration. Nagelshmidt called this process diathermy. Nowadays diathermy is commonly used as the term for all treatments with high frequency EM energies.

Short wave diathermy (SWD) uses the range of television wave at frequencies between 10 and 50 MHz. SWD is most commonly used for thermotherapy at a frequency of 27.12 MHz. The original SWD by means of the thermionic valve generator was initiated by the German Schliephake in 1929 adopted 50MHz of 6 meter wave length.

Microwave diathermy (MWD) by means of the magnetron generator uses the radar-wave commonly at a ultra-high frequency (UHF) of 2450 MHz which comes into use for the microwave oven. MWD began in the United States in 1947.

LWD uses the electric current through the body which converts into heat by the resisting tissues (Joule's heat), whereas SWD and MWD utilize the original power of EM waves. Now LWD is used only for surgery, SWD and MWD are both for the internal treatment. However, there is no principal difference between the former and the latter in the formation of heat which is generated in the endogenous manner.

TWO FORMS OF SHORTWAVE DIATHERMY

Short wave generated between two insulated electrodes i.e. condenser applicators produces an energy of electric field. This energy heats the treating area placed between two applicators. This process is the condenser field technique. The condenser field technique enables the treatment for internal deep organs because its effect involves all range between two applicators. An adequate air gap between the condenser plate and the skin surface increases deep internal heating. The four types of applicators i.e. air gap, pad, cuff, and internal are used.

Another form of SWD is the inductive (magnetic) field technique. Short wave flowing through a conductor (usually a coil) produces an energy of magnetic field. This energy heats the treating tissue placed near the conductor. The effect of magnetic field technique is restricted to superficial tissues. Three types of applicators i.e. cable, drum (minode or monode) and contour (diplode) are used. It is easy and convenient to use the drum-shaped coil-conductor. The therapeutic effect of inductive field technique is similar to that of MWD.

In the modern instruments, the practical application of SWD has become very easy because of the new automatic tuning devices. At present the internal diathermy i.e. SWD and MWD are indispensable to physical therapy especially in the field of orthopedics and rehabilitation.

2. HISTORY AND CURRENT STATUS OF DIATHERMY IN JAPAN　

Diathermy with high frequency current was initiated by Zeynek in 1895 as thermopenetration. In 1929 Schliephake established the present short wave diathermy. In 1934 the Japanese Kenji ITO (the former president of ITO physio-therapy & rehabilitation) made the short wave therapy unit. However, researches and supply of devices soon stopped because of the long continued war. Later on, in Japan particular evolution of diathermy resulting to its popularization has been gained, and now the domestic therapy unit of SWD has been utilized widely.

Since 1999 a new household pulsating unit has been made, and in 2001 an advanced pulse mode unit made by ITO PT&R will be supplied for high class hospital users.

3. BIOLOGICAL EFFECT OF SHORTWAVE DIATHERMY

In the late 1940s, the FFC (Federal Communications Commission) designated specific operating frequencies for shortwave and microwave diathermy. 13.56 MHz, 27.12 MHz and 40.68 MHz were permitted for SWD, 2450MHz and later on 915 MHz for MWD. At present, 27.12MHz is utilized most widely for SWD.

Since 1926, when E.Schliephake et al. first studied the biological action of short waves, there have been many and extensive scientific studies and papers published on them. In particular, following actions are regarded especially noteworthy.

1) marked vasodilatation of capillaries and arterioles

2) deep penetration of mild heating

3) germicidal and antitoxic actions

4) resolution of the inflammation without pus formation

5) pain relieving and sedative effect

The favorable action of shortwave therapy depends on the generation of local hyperaemia, promotion of phagocytosis, acceleration of metabolism, possible activation of the connective tissues and many other factors, namely an increase in the powers of resistance of the body.

The mechanism of heat production in the condenser field is as follows. When the electrolytes such as tissues containing some fluids e.g. the blood, blood vessels and muscles lie in the electric field, vibration of ions and rotation of dipoles takes place in them. Other tissues such as the fat which has poor conductivity produces molecular distortion. This is the principle of heating process. In the electric field the subcutaneous fatty tissues with poor conductivity are heated up more intensely than muscles below them.

On the other hand, in the magnetic field poor conductive tissues such as the skin or fat will have more reduced temperature increase. In the inductive field eddy currents are induced in the body which, in turn, are converted into heat. The heat distribution of coil field is very similar to a microwave field. Condenser field shortwave therapy carries out simultaneously same effects on two symmetrical body sections e.g. both eyes, ears and tonsils etc.

Lately non-thermal therapy with pulsed mode, on which high-output short wave energy is delivered in repeated pulses. This provides deep penetration of heat avoiding heat sensation of the skin and protecting possible burns. The shortwave therapy unit with pulsed operation mode is prevalent now.

4. THE APPARATUS FOR SHORTWAVE THERAPY

Many suitable apparatuses are currently in industrial production. 　　　　　　　　　　　　　Commonly prevalent specifications of the apparatus are as follows.

MODEL SW-180

Operating Frequency 27.12MHz

RF Peak Output 80W on Pulsed Mode

40W on Continuous Mode

Pulse Frequency 25 ~ 900Hz

Pulse Width 0.65 ~15.2ms

Timer 30 minutes digital timer

Size &Weight 835 (H)x380(W)x320(D)mm, 23Kg

Note: Genrally shortwave therapy unit made in Europe adopts an output of 200W. An output of ca.400W may be necessary for hyperthermy of the entire body.

Fig.2 shows a shortwave therapy unit, model SW-180. Fig.3 shows antenna type condenser (Schliephake) applicators, Fig.4 shows plate type condenser (Schliephake) applicators, Fig.5 shows antenna type coil (inductive) applicators.

5. THERAPEUTIC APPLICATIONS OF SHORTWAVE THERAPY

�@GENERAL REMARKS

The most specific characteristic of SWD is an immediate depth effect to penetrate the body with heat. SWD has a effect of direct weakening of virulence or even destruction of the germs, however, its good effect on the infectious inflammatory process is based much more on the activation of the body's own resistance power.

As a rule, SWD have to be used in combination with the adequate drug therapy. At the acute stage of inflammatory cases applying of weak dose i.e. "creeping" dose is recommended. There is almost no difference between coil field SWD and MWD, both are indicated to the treatment of body areas located close to the surface. On the other hand, condenser field therapy can be applied in all cases to treat all inner organs.

�ATREATMENT INDICATIONS

· Ear, Nose and Throat

acute and chronic nasopharyngitis, chronic tonsillitis, acute angina, otitis media exsudativa, Eustachian tube dysfunction, adenoid, paranasal sinusitis, external ear canal suppuration, localized lymphadenitis

· Eye

eyelid pustulosis, lacrymal cellulitis, hordeolum, uveitis, corneal desease

· Dentistry

gingivitis,oral mucosal inflammation, periodontal disease, dysfunction of the tempromandibular joint

· Surgery, Orthopedics

neuralgia, peripheral nerve paralysis, central nervous system disease, rheumatism, periscapular joint inflammation, sprains, strains

· Internal medicine

circulatory disease, haematogenic disorder, internal diseases, parotitis, gastrointestinal neurosis

· Obsterics and gynecology

adnexitis, endometritis, parametritis, blader damage

Note : As mentioned below, this manual deals with on the application of SWD for diseases of the ear, nose, and throat mainly.

6.CONTRAINDICATIONS OF SHORTWAVE AND MICROWAVE DIATHERMY

1) Patients with internal and externally worn metallic objects and electromedical devices e.g. the cardiac pacemaker, bone nails, hairpins etc.. The electric lines of force are concentrated on the metallic devices. The frequency of pacemaker will be disturbed. Hairpins should be removed as the preliminaries, then it is able to apply the treatment.

2) Individuals who are predisposed to bleeding, have any hemorrhaged disease.

3) Individuals with pain and temperature sensory deficits.

4) Microwave diathermy for low blood circulated organs, e.g. the eyes , testes etc. and its applying in the area of the head should be avoided, because such organs have poor sensitivity of over heating and the brain resonates to microwave length of 12.5cm.

5)At the application of diathermy for the whole body, such precautions are needed as an effect on the female gonad organ especially of pregnant women and on the growing bone in the childhood.

6)Tumors : Shortwave diathermy should not be applied in the region of malignant growths.

7)Patients under 2years old and who can not express their opinion like senile dementia.

NOTE: At patients with fever in an acute inflammation, if the origin of fever is nasopharynx or tonsil, it is no matter to apply shortwave therapy.

On the contrary they take a part of good indications.

7. DOSAGE OF SHORTWAVE THERAPY IN THE FIELD OF NOSE, THROAT AND EARS

　Nowadays the automatic tuning device is popular one, nevertheless it is still impossible without the invasive technique to measure the actual temperature rise in the treating tissues. Therefore as a reproducible measure of the dose in shortwave therapy, the following dose table established by Schliephake is recommended.

Dose I; lowest -- Just below the point of any sensation of heat.

Dose II; low -- Mild heat sensation, barely felt.

Dose III; medium -- Distinct but pleasant heat sensation.

Dose IV; heavy -- Heat sensation which is still well tolerated.

In the field of the nose, throat and ears, the inflammation of nasopharynx and tonsils are the most important and the best indication in the condenser field shortwave therapy, which is superior to all other methods of heat therapy, because of its greater depth effect.

Disorders of the nasopharynx and tonsils have the most important factor as original cause of all diseases of the nose, throat and ears. Avoiding the superficial heat concentration, it is necessary to take the adequate electrode-skin distance by means of felt inlays or using terry cloth toweling. A pair of flexible pad electrodes put on the both auricles. Generally irradiation of Dose III and IV of 3〜5 minutes, and its 2 or 3 times a week are applied. It is necessary, however, to apply daily or on every other day in acute inflammatory conditions especially in the acute nasopharyngitis and tonsillitis.

Shortwave diathermy of condenser field technique using the adequate electrode-skin distance is very effective for diseases of organs located farther inside the body e.g. tonsils, Eustachian tube and adenoid etc.. On the other hand microwave therapy has smaller effects for these inside organs because its effect is shallow and limited. Shortwave therapy of coil field method has likewise poor effects on such inside organs. These two techniques are more effective for the superficial tissues.

8. INDICATIONS OF SHORTWAVE DIATHERMY FOR DISEASES OF THE NOSE, THROAT AND EARS

　As a rule the medication of antibiotics or other effective drugs and the appropriate local treatment for each organs have to be applied together with shortwave therapy.

The condenser field technique with the sufficient electrode-skin distance may be indicated for the disorder of inside organs. The coil field technique may be applied to the disorder of superficial organs e.g. inflammation of the external ear, middle ear and disturbance of the inner ear etc..

NASOPHARYNGITIS, TONSILLITIS AND WALDAYER'S RING DISORDERS

In order to diagnose and to heal nasophryngitis quickly, it is recommended as the best means to apply local swabbing of 1% ZnCl 2 solution. At its swabbing the abrasion of the regional mucosa is accompanied by some pain in all cases. Furthermore in severe cases postabrasive mucosal bleeding are observed and the pain continues for several hours. At the same time this swabbing is the most effective treatment for nasophryngitis together with shortwave diathermy. In diseases of Waldeyer's ring e.g. acute tonsillitis the same dose and frequencies of SW(shortwave) treatment may be indicated as in nasophryngitis. In the acute case the condenser field treatment of either Dose III or IV of 5〜3 minutes are applied once or twice a day until its healing. This is also effective in the acute peritonsillitis preventing its suppuration. In the cases of acute tonsillitis and adenoiditis it is better to medicate antibiotics together with shortwave therapy. So called habitual angina which repeats the acute tonsillitis over 4 times a year, will be able to heal just after 20〜25 times of SW treatment with no medication. So this frequency (20〜25 times) of SW treatment is regarded as one curing-unit. This is the fundamental dosage of shortwave diathermy almost in all cases of chronic disease of the ear, nose and throat regions.

In the chronic tonsillitis and adenoid (hyperplasia of the nasopharygeal tonsil) the same dosage as mentioned above may be indicated 2 or 3 times per week. Nasal obstruction will be better after ca. 15 times of treatment in the majority cases of adenoid. When its effect is insufficient, operative means may be considered. In the such case electrocoagulation on the unilateral palate tonsil by means of longwave diathermy is recommended because it has a remote effect which shrinks the hypertrophied nasophryngeal tonsil.

The severe cases of chronic tonsillitis in adults need many curing-units of treatment. After long period treatment the inflammatory tonsils will obtain almost the normal condition. In these cases, however, electrosurgery is more preferable rather than physical shortwave therapy.

SECRETORY OTITIS MEDIA AND EUSTACHIAN TUBE DYSFUNCTION

　In spite of medication of many kinds of drugs or local administration of drugs and surgical drainage by the plastic tube through the drumhead, secretory otitis media remains as a hard disease to heal. The fluid accumulation in the middle ear continues for a long period. This is most common in children and is associated with many complicated causes such as adenoid hyperplasia or infection of the nasopharynx. There is, however, no doubt that the improvement of poor patency of the Eustachian tube has the greatest interest to protect the fluid accumulation. As mentioned above the condenser field method has the greatest depth effect, so it has the most superior effect to improve the poor tubal patency in these conditions. The coil field technique has poor depth effect, nevertheless it promotes well the resolution and absorption of the fluid in the middle ear. So simultaneous applying of both methods carries out the remarkable improvement.

Generally the fundamental dosage of 20〜25 times treatment may be indicated. In the severe cases it is necessary to treat hardly, to repeat more curing-units until its healing. To obtain quick healing in these cases, electrosurgery (longwave diathermy) on the palate tonsil is recommended. As mentioned above it (eletrocoagulation even if on one side) has a remote effect to shrink the hypertrophied adenoid and reduces the inflammation in pharynx.

ACUTE TUBAL CATARRH

This is a disease secondary to the acute nasopharyngitis and an early or developmental stage of acute otitis media. This is also treated with good results by shortwave treatment of the condenser field method.

OTITIS MEDIA

In an early stage of acute otitis media and its recovery stage, application of the coil field shortwave treatment carries out good results to reduce its inflammatory process and to promote the healing. Placing the coil field electrode (Monode) too close to the skin will give overheat sensation, so it is better to take slight spacing by terry cloth within 1cm of the skin. In cases of fluid accumulation in the ear e.g. pus, thin transudate or thick exsudate, it is often necessary to remove the fluid surgically. Then shortwave therapy may be applied more effectively. In cases of the acute vigorous stage especially with no perforation of drumhead, it is better to medicate antibiotics and indicate no shortwave therapy, because there is a danger to increase the pain and aggravate the inflammatory process.

In chronic middle ear suppuration, only the cases with central perforation respond to treatment. In the too much responsive case aural discharge may increase after the treatment. Then it is better to indicate no application or to use Dose I〜II politely.

HEARING DISORDERS AND TINNITUS

Generally in cases of chronic sensorineural disorder and its tinnitus, shortwave therapy has only a poor or nearly no effect. In some cases, however, good results more over the psychological one are obtained. Especially some cases of suddenly occurred sensorineural hearing loss well respond to treatment. It is considered that improvement of sensitivity of sensorineural organs mainly depends on an increase in the regional blood circulation and its activating effect.

Some cases of hearing loss with the air-bone gap, that is, a combined or mixed hearing loss responds well to the condenser field treatment. Moreover in the case which has a greater extent of bone conduction loss than usual conductive disorders, it carries out a distinct result. It is sure that such an inordinate great bone conduction loss shows the presence of hypersensitivity of the inner ear. Maybe this is caused by an excessively raised overreaction to the adjacent inflammation in the middle ear. The penetrating depth effect of condenser field therapy improves not only the dysfunction of middle ear but also of the inner ear.

Conductive hearing loss in the otitis media well responds to treatment with reduction of the inflammation. Then the coil field therapy is likewise effective as the condenser field treatment.

PARANASAL SINUS INFECTIONS

　Acute cases of Sunusitis frontalis and Sinusitis maxillaris well respond to both condenser and coil field treatment. In the former treatment an electrode should be placed on the forehead or on the face above the cheek, the equal size remainder either above the occiput or at the neck. In the latter only an eddy-current electrode (Monode) is arranged on same points as in the former. In addition to these treatment some drugs and adequate antibiotics should be applied together.

Shortwave diathermy is likely effective for the chronic sinusitis, in particular to the obstinate pain in the case of postoperative maxillary sinus-cyst. When using the monode, a strict attention to avoid irradiation on the eye is needed.

FURUNCLE, DISEASES OF THE SKIN

　 Inflammatory external otitis responds well to shortwave diathermy especially to coil field treatment. At the same time to prevent suppuration an early medication of adequate antibiotics is recommended. As the result a little or no suppuration and quick healing carries out almost in all cases.

Generally chronic eczematoid external otitis and myringitis are difficult to heal . To promote healing in such cases the microwave diathermy is very effective likewise as the shortwave radiation with a monode ( coil field treatment ).

9. CLINICAL APPLICATIONS OF DIATHERMY IN THE NOSE THROAT AND EARS

INDICATIONS OF CONDENSER FIELD TREATMENT

Condenser field treatment may be applied for the complicated diseases in the ear, nose and throat regions especially for deep structures. Disorders of Waldeyer's ring and many others caused by its origin are the best indication. In particular, diseases on which medicine has a poor effect or has not to be prescribed such as Epstain-Barr virus (EBV) Angina, the nasopharyngitis and tonsillitis in pregnant women etc. should be indicated the treatment as the best choice. The secretory otitis media in children who hate any local treatment is one of the best indication of both condenser and coil field treatment.

INDICATIONS OF COIL FIELD TREATMENT

This may be indicated for the localized disease of superficial structures, e.g. furuncles in the external ear canal, otitis media, suddenly occurred hearing loss of inner ear origin and lymph nodes swelling in the neck region etc..

BIBLIOGRAPHY

THOM,H.："Introduction to shortwave and microwave therapy" 3rd Edition, Springfield,C.C Thomas,1966.