SHORTWAVE DIATHERMY

Dr.prashanth kumar1st yr pg in orthopaedics

Diathermy is a therapeutic treatment commonly prescribed for muscular and joint associated pains.

The term ‘diathermy’ means ‘through heating’ or producing deep heating directly in the tissues of the body.

• ‘ Dia’ through (also means two)• ‘thermy’ heat or temperature

It simulates the circulation, relieve pain, enhances rate of recovery of healing the tissue.

INTRODUCTION

PRINCIPLE OF DIATHERMY1.Before injury, the dipole molecules of the body

tissue are arranged on the basis of polarity .

2.When the tissue is damaged the dipoles distribution become irregular and deviates from polarity based arrangement .

3.Under the influence of an electric field , they rotate according to the polarity of their charge in the direction of the field lines and get rearranged and tends to acquire its previous stage of polarity

CHALLENGES OF DIATHERMY1. As the subcutaneous layer is fatty , direct delivery

of heat to the deep layers of tissue is not possible.

2. Diathermy involves uneven and uncontrolled delivery of heat therefore sometimes instead of the target tissue , surrounding tissue gets affected

Subcutaneous layer

• Diathermy uses an electric current to produce heat deep inside a targeted tissue.

• It can reach areas as deep as two inches from the skin’s surface.

• The diathermy machine does not apply heat directly to the body.

• Instead, the current from the machine allows the body to generate heat from within the targeted tissue.

• As the heat increases, it promotes blood flow. • It can also help improve flexibility in stiff joints and

connective tissue.

BENEFITS OF DIATHERMY

Intense heat delivered provides pain relief and better flexibility

Reduces inflammation

Improves circulation

Accelerate healing

TYPES OF DIATHERMY

1. SHORT WAVE DIATHERMY

2. LONGWAVE DIATHERMY

3. MICROWAVE DIATHERMY

4. ULTRASOUND DIATHERMY

5. LASER DIATHERMY

SHORT WAVE DIATHERMY Def.: SWD is a modality that produces deep

heating via conversion of electromagnetic energy to thermal energy.

• The pattern of heat produced depend on:• ᴥFreq. used. • ᴥ type of SWD unit. • ᴥwater content of the tissues.

Shortwave diathermy current freq. 10 – 100 MHz

• (The shortest radiofrequency wave is used in therapeutic diathermy.)

• the commonly used in medical work having freq. of 27.12 MHz with wavelength of 11 meters

Modalities: ether continuous or pulsed (PSWD).o PSWD: application of series of short pulses of

SWD so that short periods of SWD interrupted by gaps where there is no SWD.

o The pt. receives lower dose of SWD energy if compared with continuous SWD applied of the same time.

o The tissues will receive lower thermal load.

• SWD: produce both deep and sup. Tissue heating, under certain controlled conditions

• it’s applied for 20 min at the max tolerable dose

Types of Shortwave Diathermy

• Induction Field

• Capacitive Field

Induction Field Diathermy• Places the patient in

the electromagnetic field• Current flowing within

the coil produces a rotating magnetic field

• Magnetic field produces eddy currents in the tissues

• Eddy currents cause friction that produce heat

• Selectively heats muscle• Also referred to as:• – Magnetic field

diathermy

Capacitive Field Diathermy• Uses the patient’s tissues

as a part of the circuit• The tissues’ electrical

resistance produces heat• Selectively heats skin– Muscle is heated via

conduction from theadipose

• Also referred to as “condenser field diathermy”

TYPES OF ELECTRODES

• Flexible pads: consist of metal electrode encased in rubber and produce an electrostatic field.

• Space plates: consist of a rigid metal electrode encased in

• a Perspex cover €electrostatic field.

• Coil or cable electrode consists of a wire with plugs at either end creates electromagnetic field.

• The monode : flat, rigid coil encased in plastic cover € electromagnetic field.

• The diplode : or drum electrode, consists of a flat coil electrode encased in a Perspex cover with two wings € electromagnetic field

FACTORS INFLUENCE FIELD DISTRIBUTION IN S.W.D

◉ Spacing :• allows the lines of force in the electrostatic field to diverge before entering the tissues. This prevents concentration of heat in the superficial tissues and ensures more heating through the part.

• Spacing provided by:1. wrapping flexible pads in towel.2. flat felt spacing pads between

pad electrode and skin3. air when using space plates.

• Normal spacing € even field distribution.

• Increased spacing € deep field concentration.

• Decreased spacing€ superficial concentration

•◉ Electrode size:• if the electrodes are too small than the diameter of treated part line of force will be concentrated superficially.

• ◉ If the electrodes are markedly larger the line of force will be lost in the air.

• ◉ Ideally, the electrodes should be slightly larger than the area treated.

• To concentrate heat on one aspect of the part the electrode should be unequal in size (smaller one placed over the area where concentration of heat is required).

• You can produce concentration of heat by using equal size electrodes but with unequal spacing (25 mm over concentrated area and more than 30 mm on other electrode).

THERAPEUTIC VARIATION IN THE FIELD DISTRIBUTION

Coplanar application to structures on one aspect of the body. If the spacing is less than 25 mm more concentration in the treat superficial tissue.

If spacing Increases more depth achieved

.The distance between adjacent ends must be greater than the sum of skin electrode distance (A+B) otherwise the line of force willpass directly between Electrodes rather than tissues

• Contra planar applications

• Two flexible pads, two space plates

or flexiblepad with a space plateare used.

• It is essential to put a cotton towel between the two limbs to any absorb perspiration.

• Cross-fire application:For the treatment of sinuses,space plates positioned after half diagonally,of treatment time the positions are alternate.this ensures that the all the sinses membranesare heated.Care must be taken to avoid direct placement over the eye ,uterinedisorders such as dysmenrrohea.

• Application using a coil electrode:

• 1. The coil wound evenly firmly

• 2 Pancake application

• Application using diplode:

• Adjust wings of diplode parallel to the skin of the treated area, electromagnetic field will produce.

PHYSIOLOGICAL EFFECTSThe principal effect of SWD on the body is the production of heat in the tissues due to the rise of temperature.1. Increased metabolism:• Heating tissues accelerates chemical changes

such as metabolism, so oxygen and food stuffs are used up.

• With increased metabolism, there will be increased output of waste products.

Increased blood supply:• As a result of increased output of waste products

such as metabolites, which act on the walls of the capillaries and arterioles, these tissues dilate.

• In addition, heat has direct effect on blood vessels, causing vasodilatation.

• Heat also produces stimulation of superficial nerve endings, causing reflex dilatation of the arterioles.

. General rise of temperature:• As blood passes through the heated tissues, it

also becomes heated and carries the heat to other body parts.

• Rise of temperature induces muscle relaxation and increases the efficiency of muscle action.

. Fall in blood pressure:• The generalized vasodilatation reduces the

peripheral resistance to blood flow. • Heat also reduces blood viscosity, which helps

in the reduction of blood pressure.

. Increased activity of sweat glands:• If a general rise of temperature occurs, there

will be increased activation of the sweat glands.

Therapeutic Uses• Effect on Inflammation

Vasodilation O2 and Nutritive material

Antibodies & White blood cells

Assist in removal of Waste ProductsAll these effects bring about resolution of inflammation

. Effect on Bacterial Infection• Inflammation is normal response of Body to bacteria

• Heating the tissue auguments these changes so reinforces body's normal mechanism to of dealing with infecting organisms

Ex. Boils, Carbuncles, Abscesses

. Reducing Healing time• Increased Blood supply• More Nutritive Material• More O2 supply

. Relief of Pain• Sedative Effect• Removal of Waste Products• Resolution of Inflammation• Counter irritation

Effect on Muscle Tissue• Muscle relaxation• Relief of Muscle Spasm

• Musculoskeletal Disorders Degenerative Joint Disorders

Ex. OA and RA Sprain Strain Hematoma Muscle & tendon Tears Capsule Lesions

USES

• Inflammatory Conditions Boils Carbuncles Sinusitis Pelvic Conditions Infected Surgical Incisions

DANGERS1. Burns

• Concentration of electric field• Excess current• Impaired blood flow• Hypersensitive skin• Leads touching skin

1. Scalds2. Electric shock3. Overdose4. Precipitation of gangrene5. Faintness6. Giddiness

Contraindications• Metal implants or metal

jewelry (be aware of body piercings)

• Cardiac pacemakers• Ischemic areas• Peripheral vascular disease• Perspiration and moist

dressings: The water collects and concentrates the heat.

• Tendency to hemorrhage, including menstruation.

• Pregnancy• Fever

• Sensory loss• Cancer• Deep X ray• Tumours• Unreliable patients• Areas of particular sensitivity:

– Epiphyseal plates in children– The genitals– Sites of infection– The abdomen with an

implanted intrauterine device (IUD)

– The eyes and face– Application through the skull