Short–wave diathermy is the application to the tissues of electrical fields which oscillate at a frequency of 27.12KHz and have a wavelength of 11.06M (condenser field method). The oscillating fields produce distortion of molecules, rotation of dipoles and vibration of ions. When the inductothermy cable is used there is a current oscillating in the cable which produces an electromagnetic field, which in turn induces eddy currents (and therefore ionic vibration) in the tissues. The movement of the molecules and ions generates heat within the tissues. Tissues of high impedance are bone, fat, fascia and other fibrous tissue structures. Tissues of low impedance are blood, lymph and muscle. If the oscillating electrical field is applied in parallel with the tissues, then those with low impedance will tend to be heated more, whereas the tissues of high impedance will be heated if they are in series with the field. The superficial tissues of low impedance tend to be heated when the inductothermy cable is used.
Short–wave diathermy can be used to treat both deep and superficial lesions. Large areas can be treated and it is useful for soft–tissue injuries, degenerative and inflammatory arthropathies, slow healing wounds, sinusitis and conditions of the deep–seated pelvic structures.
Short-wave DiathermyShort–wave diathermy may be pulsed (one form of pulsed electromagnetic energy–PEME). This mean power is, therefore, considerably reduced. The main difference is that during the relatively long rest period, the heat developed is dispersed by the circulation and the treatment is referred to as ‘non–thermal’. Pulsed SWD is particularly useful for giving pain relief in acute soft–tissue lesions and arthropathies. In crush injuries or trauma which results in excessive swelling, pulsed SWD obtains marked reduction in local edema. For acute lesions the recommended dosage is 65 us at 100 pps for 15 minutes.
Progression of treatment, if necessary, involves increasing pulse widths and frequencies. The possibilities of varying the treatment depend upon the machine used. In wounds treated with pulsed SWD there is increased organization of connective tissue and growth of epithelial tissue so that healing is accelerated. Areas with metal in the field which are a contraindication to continuous short wave may be treated with pulsed SWD.
Transcutaneous Electrical Nerve Stimulation (TENS)
Transcutaneous Electrical Nerve Stimulation (TENS) is a method of producing pain relief by the application of a pulsed biphasic rectangular wave form through electrodes on the skin. The principle of working is related to the pain gate theory (Melzavk and Wall, 1965, 1982). There is closing of the gate by stimulation of A–fibers and activation of the descending pain suppression system. It has been suggested that 50–100Hz achieves this effect. Low frequency (2 Hz pulsed) is said to relieve pain by increasing the body’s production of endorphins.
The Transcutaneous Electrical Nerve Stimulation stimulators are commonly small battery–operated machines with a current output of 0–50mA. The pulse widths may be fixed at 200 us or variable between 50 and 300 us. The frequency is also variable on most machines from 2 Hz to 300 Hz, although some are fixed at 150 Hz. The low frequencies are used for chronic pain and the slightly higher (80–120 Hz) for acute pain. The wide variables of pulse width, frequency and current output allow adjustments for the individual.
The electrodes are applied with conducting gel and are self–adhesive or fixed with tape. Their position may be above and below the painful spot, over the affected nerve, nerve trunk or the affected dermatome. They should not be applied over anesthetic areas because there would be no sensory input. Prolonged stimulation is necessary to be effective, e.g. 8 hours per day for a week, but 24 hours a day may be necessary. The patient may require the machine for 2–3 months.
Uses of Transcutaneous Electrical Nerve Stimulation (TENS)
- Longstanding severe pain in a variety of conditions.
- Post–herpetic neuralgia.
- Stump and phantom limb pain
- Trigeminal neuralgia
- Chronic neck, back or leg pain.
- During labor.
Contraindications of Transcutaneous Electrical Nerve Stimulation (TENS)
Patients with pacemakers or cardiac arrhythmias. Area of carotid sinus and mouth.
- Where the cause of pain has not been diagnosed by a qualified health care practitioner.
- By any person with a heart pacemaker.
- By any person with a serious/unstable heart condition.
- By any person with epilepsy.
- When electrodes are placed across the chest, i.e. both arms simultaneously.
- When electrodes are placed on the neck in the region of the carotid arteries.
- Where any area of skin is inflamed or infected.
- If an allergic reaction develops to adhesive tape or electrodes.
- Around the head.
Medium–frequency currents alternate at 1000–100 000Hz. Interferential therapy is the use of two medium–frequency currents around 4000 Hz to produce a low–frequency effect within the body without the problem of high skin resistance. Low–frequency is required to high skin resistance, require a high intensity to achieve the desired effect and this causes marked sensory stimulation to the part. Medium–frequency causes low skin resistance require a low intensity to achieve the desired effect, which in less sensory discomfort. High–frequency currents, such as short–wave diathermy and microwave, have frequencies too high to stimulate skin on muscle and produce only thermal effects.
In interferential equipment one frequency is fixed at 4000 Hz (generated by one pair of electrodes) and the other is variable between 4000 Hz and 4200 Hz (second pair of electrodes). By selecting the variable frequency, a beat frequency between 0 and 200 Hz may be generated.
Indications for Interferential Therapy
- Pain relief–Pain of sympathetic origin such as causalgia, neuralgia, pain from herpes zoster, amputation–stump complications and recent injuries.
- Swelling–Interferential aids absorption of exudates particularly for Haematoma.
- Stress incontinence–The muscle stimulating frequencies aid weak pelvic floor muscles
- Back pain or disc lesions–Interferential therapy is useful for relief of acute back pain where the pain is localized to the back or referred down a lower limb.
- Sudeck’s atrophy–This responds to interferential when other modalities have failed but treatment may need to be prolonged.
- Ligamentous and muscle injuries–Interferential can be given in acute or chronic conditions to relieve pain, promote healing and restore function. Treatment can be given with strapping in place.
- Rheumatic conditions–Relief of pain arising from Osteoarthritis, rheumatoid arthritis and Ankylosing spondylitis may be obtained, with a resulting increase in function.
- Pacemakers–Patients with pacemakers should avoid high and medium–frequency currents.
- Malignancy–Spread of the disease may occur
- Pregnancy–Treatment should not be given to the pelvic organs during pregnancy.
- Bacterial Infections–Treatment may cause spread of the infection.
- Thrombosis–Interferential tends to spread the blood clot and is contraindicated in deep venous thrombosis or thrombophlebitis. The heart and stellate ganglion should also be avoided.
Infra-red radiationWhen the radiations are absorbed the radiant energy is converted to heat.
There are two types of generators.
- Luminous, producing rays from 350 nm to 450 nm which penetrate the epidermis and dermis to the subcutaneous tissues.
- Non–luminous, producing rays from 770nm to 1500 nm which penetrate only as far as the superficial epidermis.
Owing to these effects, infra–red can be used to promote healing in uninfected wounds, relieve pain and reduce muscle spasm following trauma, and for chronic arthritic joints, when the luminous generator should be used. The sedative effect of the non–luminous generator is more suitable for recent trauma and sub acute inflammatory joints. Infra–red is used to treat large superficial areas.
The paraffin wax has a low melting point and is contained in a bath thermostatically controlled between 40°C. Owing to its low thermal conductivity, wax heats more slowly but retains its heat for a longer period than water. As the paraffin wax solidifies on the skin the energy released by the latent heat for a longer period than water. As the paraffin wax solidifies on the skin the energy released by the latent heat of fusion results in heating of the tissues.
The advantages of paraffin wax are that it completely surrounds the part being treated and the patient does not need to remain in a fixed position. Also it is applied at a known temperature and gets cooler–therefore there is very little danger of a burn. Its disadvantages are that regular cleaning is necessary and it is difficult to apply except to the extremities. Its main use therefore is in treating hands and feet. Paraffin Wax is used to relieve pain after trauma, in degenerative joint disease and in the chronic stage of inflammatory arthropathies. Skin condition can be improved following the removal of plaster of Paris. Adhesions and scars can be softened and mobilization is facilitated. It should not, however, be applied over open wounds or skin infections.
Laser The word laser is an acronym for Light Amplification by Stimulated Emission of Radiation. It obeys the laws of radiation. Specific substances are stimulated laser rays electrically to emit radiations which produce greater energy levels. The helium/neon mixture produces a red light and the infra–red produces no light. The probe may produce a single wavelength or a cluster of wavelengths. Laser is different from other forms of light because it is monochromatic (one wavelength only), the beam of light being narrow, parallel and uniform. The laser waves are identical, superimposing on each other and therefore giving an amplifying effect.
There are three types of lasers:
- Power laser used in surgery for destructive effect.
- Soft laser (helium/neon) used for superficial lesions of the skin.
- Mid–laser (gallium, aluminum, arsenide). The wavelength produced depends on the ratio of each material. These are most commonly used because of their depth of penetration (30–40nm).
- Increases collagen synthesis–useful for tissue repair.
- Increases permeability of cell membranes with increased efficiency of sodium.
- Increases number of fibroblasts and promotes granulation tissue–useful for wound healing.
- Increases levels of prostaglandin. Causes an increase in cellular ATP, which is useful for pain relief.
- Open wounds–ulcers, postoperative wounds.
- Skin conditions–psoriasis, burns.
- Soft–tissue injuries–tendons, ligaments and muscles.
- Degenerative and inflammatory arthropathies.
- Pain relief over trigger or acupuncture points.
- Skin irritation.
- Chest treatment in cardiac patients should be avoided, together with those who have a pacemaker.
- The eyes.
These are plastic–covered pads similar to but smaller than electric blankets. A pad has three levels of heat and is useful for treating the neck or back. The patient lies on it and heat passes to the tissues by conduction. An advantage is that the heat can be applied at the same time as traction.
Hot moist packs
These are canvas bags filled with a hydrophilic substance and stored in a thermostatically–controlled cabinet of water between 75°C and 80°C. The packs vary in size and shape and are returned to the cabinet for reheating after use. The area to be treated should be totally covered by the pack, which is molded to the contour of the body. Layers of toweling must be placed round the pack to separate if from the patient’s skin. The superficial tissues are heated by conduction, relieving pain and muscle spasm. Moist heat is conducted more uniformly than dry heat. These packs are particularly useful on uneven surfaces because they can be easily molded to the surface, but they are heavy and may cause discomfort.
Ultraviolet Rays (UVR)
These are electromagnetic rays between the visible rays and X–rays in the electromagnetic spectrum (400–100nm).
The ultraviolet rays are produced ultraviolet by vaporization of mercury in a quartz tube. All ultraviolet burners produce visible and infra–red–rays. For therapeutic sources of Ultraviolet Rays. In the Kromayer lamp water absorbs the infra–red rays and allows treatment in contact with the patient’s skin. With the air–cooled source the patient is treated at a distance of 45 cm or more to avoid burning of the skin from the infra–red rays.
Laws of radiations
A larger area is irradiated but the intensity is decreased when the distance from the source to the patient’s skin is increased. Ultraviolet Rays are governed by the law of inverse squares which states that the intensity of rays falling on a plane surface varies inversely with the square of the distance from the point source. To irradiate a smaller area the source is moved nearer to the patient but the time of exposure must be altered to maintain the same intensity in accordance with the law of inverse squares.
Now time =
Old time x (new distance)2
Ultraviolet Rays must strike the surface at 90° to the erythema reaction after an E1 has been determined from a skin test.
The other erythema dosages can be calculated as follows:
- Suberythema 75% of E1.
- E2 = 2.5 x E1.
- E3 = 5 x E1.
- E4 = 10 x E1.
- Double E4 = 20 x E1.
- E4 + Double E4 are used on open wounds.
When Ultraviolet Rays is applied to normal skin there is thickening of the epidermis therefore progression of dosage is necessary to obtain the same effective level.
Doses can be progressed as follows:
- Suberythema–previous dose plus 12.5%.
- E1–previous dose plus 25%.
- E2–previous dose plus 50%.
- E4–previous dose plus 75%.
Contraindications to Ultraviolet Rays
- Deep X–ray therapy during the preceding 3 months because the skin may be hypersensitive to UVR.
- Tuberculosis or malignant disease may be exacerbated by UVR.
- Hypersensitivity to sunlight–patients who react adversely to the sun should not be treated with Ultraviolet Rays
- Dermatological conditions such as acute eczema, lupus erythematosis may be exacerbated by UVR.
- After infra–red therapy–UVR given whilst the erythema from the infra–red is still present may result in increased effects.
- Pyrexia–Ultraviolet Rays may produce a further increase in temperature.
Hydrotherapy in the strictest sense refers to the therapeutic use of water. Pool therapy should be considered for patients with problems arising from muscle weakness, loss of joint mobility, poor coordination or balance, pain or lack of confidence. The particular value of pool therapy over dry–land treatment is derived from buoyancy, which counteracts gravity, provides support and relieves weight–bearing pressure on joints, for example in degenerative conditions. The warmth of the water reduces pain and can relax muscle spasm. The medium enables mobility for patients who may be wheelchair–bound or recovering from prolonged immobilization. Importantly, it also provides for enjoyment, recreation and laughter which are vital aspects or rehabilitation. Physiotherapists should consider pool therapy when treating patients with:
- Ankylosing spondylitis.
- Rheumatoid arthritis.
- Juvenile chronic polyarthritis.
- Mechanical spinal disorders.
- Polymyalgia rheumatica.
- Major fractures especially of the lower limbs or spine.
- Orthopedic surgery.
- Neurological disorders such as hemiplegia, paraplegia, tetraplegia, polyneuropathy.
- Children derive particular benefit from the freedom of movement afforded by the water.
- Pool therapy is also of value for maintaining fitness and relieving backache during pregnancy and after childbirth.
Muscles are strengthened by being worked progressively against graded resistance. In the pool, resistance may be from buoyancy, turbulence.
Movement downwards in the pool are resisted by buoyancy. Floats which may be of different densities may be used to increase the effect of buoyancy.
This is created by movement through water and is increased if the rate of movement is increased. The patient may move as a whole through the water–this is the principle underlying muscle strengthening using Bad Ragaz techniques. Alternatively, the patient may be fixed and move one limb at a time. Walking fast through water is useful for strengthening muscles and for improving cardiovascular fitness.
Relief of pain and muscle spasm by the warmth of the water and by support from buoyancy can restore free movement of joints. Exercises for gaining mobility are generally slow, taken to the point of limitation, held, carried a bit further and then relaxed. Full–range sweeping movements also gain range (the speed is kept to a minimum so that the muscles are not working against turbulence). Hold–relax and repeated contractions may be used to gain joint movement–generally with the patient in lying (buoyancy supporting) or positioned so that buoyancy may assist in gaining the movement.
Mobilizations–Oscillatory passive movements can be applied to joints to gain range. Fixation is a problem and it may require two physiotherapists, one fixing and one producing the movement, to localize the effect to the joint being treated. Patients report considerable relief from pain following mobilization in the pool.
Coordination and balance
Patients can practice activities in standing, for example stride standing or walk standing , transference of weight, or arm movements. The buoyancy of the water relieves weight, for example 90% relief is obtained if the water is over the shoulders, therefore weight–bearing activities such as walking, stepping up and down, standing up and down can be practiced in the pool before the patient attempts these activities on land. Components of swimming can be practiced, for example the leg patterns of different swimming strokes may be performed while the patient holds the pool rail. Swimming and ball games, Bad Ragaz techniques and the Halliwick principles all help patients to regain coordination. The special value of the Halliwick approach is to teach the patient breathing control and balance in the water, thereby enabling him to the water–confident.
The general freedom of movement in a pool enables tissue fluid to flow through tissue planes, removing metabolites and improving nutrition. These effects, together with a feeling of well–being after physical activity, help to gain permanent reduction of pain. In some pools there is a facility for applying a high–pressure jet of water to a painful area. The patient is standing, sitting or lying and the physiotherapist directs the jet at the area to be treated and moves if either in circles or to and fro for 5–10 minutes. Patients report relief of the aching which is often associated with muscle spasm or tightness in degenerative conditions or chronic injury.
Cooling of the tissues–ice therapy
Ice therapy is the local or general application of cold for therapeutic and preventative uses. When ice is applied to the skin it melts and removes heat from the tissues–the energy required to change its state (the latent heat of fusion). The rate at which cooling occurs depends on the duration of the application, type of tissue (e.g. the thermal conductivity of muscle is greater than that of fat) and the patency of the blood vessels.
Therapeutically, ice can be used to relieve pain and muscle spasm, reduce swelling, reduce spasticity, facilitate muscle contraction, increase muscle endurance, reduce Haematoma formation, prevent pressure sores and promote healing of wounds.
Ice can be applied in towels, as a pack or by immersion in a bath. Damp towels dipped in an ice–and–water mixture, or containing crushed or flaked ice, can be wrapped round painful and swollen joints. Towels are applied longitudinally along muscles to reduce spasm. The towels are changed every few minutes. Ice baths containing 50–60% ice to water are used for painful swollen hands or feet. Spasticity can also be reduced by immersion in a bath.
In ice massage, an ice cube or ice lolly is wrapped a towel at one end and the free end is massaged over the skin. This can act as a counter–irritant if applied for 5–7 minutes to relieve pain and muscle spasm and as a preventative measure to avoid pressure–sore breakdown. This method may be used to facilitate the following:
- Muscle contraction, by application over the appropriate dermatome for 3–5s.
- Swallowing, by application over the skin just above the suprasternal notch or sipping iced water.
- Speech, by application to the lips, tongue and inside of the cheek.