Lecture 3 Shortwave Diathermy PDF

Shortwave Diathermy  Diathermy is a Greek word “to heat through”, and involves the use of EM energy passing through and being absorbed by the body and then converted into heat to produce physiological effect for therapeutic purposes.  Types of Diathermy  1.Shortwave Diathermy (SWD)...

Shortwave Diathermy  Diathermy is a Greek word “to heat through”, and involves the use of EM energy passing through and being absorbed by the body and then converted into heat to produce physiological effect for therapeutic purposes.  Types of Diathermy  1.Shortwave Diathermy (SWD)  2.Microwave Diathermy(MWD) What is shortwave diathermy (SWD)?  The SWD is an electromagnetic wave used by physiotherapy with the frequency of (27.12) MHz and it can go deeper within the body tissues than other modalities, such as infrared and hot packs. SWD can penetrate the body to about 5 Cm.  Short-wave diathermy is a modality that produces heat by converting electromagnetic energy into thermal energy in the body tissues. Also be used to produce non thermal effects. Types of Shortwave Continuous SWD (CSWD): Continuous production of electromagnetic current to produce thermal effect. 1  Pulsed SWD (PSWD):  Interrupted production of electromagnetic current to produce non- thermal effect.  Short periods of SWD interrupted by gaps where there is no SWD. So the patient receives lower dose of SWD energy if compared with continuous SWD applied of the same time and the tissues will receive lower thermal load.  So it could be used in management of acute conditions. Production of Shortwave Diathermy SWD have two main circuits:  The machine circuit which produce electromagnetic current  The patient circuit through inductors (electrodes) to transfer SWD to the patient. 2 Physiological Effect of SWD 1- Shortwave diathermy doesn’t stimulate motor or sensory nerves, so when the current is passed through the body tissues, there is no discomfort and no muscle contraction are produced. 2-The main effect is the tissue heating. Tissue heating leading to: a- Increase blood flow (dilatation of the blood vessels) b- Effects on inflammatory process: Dilatation → increase blood flow → increase supply of O2 and nutrition → bringing more antibodies and WBCs → which assist in removal of waste products. This effect helps in the resolution of inflammation c- Increase extensibility of deep collagen tissues d. Increased metabolism: Heating tissues accelerates chemical changes such as metabolism, so oxygen and food stuffs are used up. e- Reduction of muscle spasm f- Promotion of healing through:  Increased Blood supply  More Nutritive Material 3   More O2 supply g- Relief of pain through:  Increased Blood supply  Removal of Waste Products  Resolution of Inflammation  Counter irritation Indications and therapeutic uses of Continuous SWD: Shortwave diathermy can be used to control pain and edema. Shortwave diathermy (SWD) is commonly used to treat a variety of musculoskeletal conditions, including:  Sprain and Strain  Frozen shoulder  Degenerative joint disease ((Example: Osteoarthritis (OA) and Rheumatoid arthritis (RA).  Joint stiffness.  Tenosynovitis  Arthritis  Tendinitis  Bursitis  Myofascial pain.  Lumbar pain.  Tennis elbow, etc  Speeding the recovery of wounds 4 Contraindications of Shortwave Diathermy: 1- Loss or impaired skin sensation (leads to burn). 2- Impaired circulation (ischemia or varicose veins) the inability of the circulation to disperse heat could result in high temperature – Burns. 3- Hemorrhage Increase vasodilatation, prolong hemorrhage. 4- Venous thrombosis. (Can dislodge the clot or aggravate the inflammation). 5- Abnormalities of blood pressure 6- Sever cardiac conditions 7- Fever 8- Metallic implant in the tissues Concentration of the field. (Increase heating which leads to burn) 9- Tumors / Malignancy (SWD increases growth of tumors). 10- Hyper sensitivity to heat 11- Uncontrolled or unreliable patient (Mentally retarded patient, young children, patient unable to understand and unconsciousness patient). 12- After recent deep x-ray therapy. Parameters of Treatment 1-Intensity of SWD The intensity of heating based on: The patient’s perception of heat felt during treatment. The sensation of comfortable warmth is the only safe measure for the intensity of treatment. 2-Duration of treatment: - Mild conditions: 15-20 min. - Chronic conditions: 20-25 min. 5 - Larger area as low back: up to 30 minutes 3- Frequency of treatment: The number of treatment depend on patient’s reaction to the therapy. - Daily if the dosage of SW is low. - Usually three-times weekly Pulsed Shortwave Treatment (PSWT) Definition: Itis short wave at the frequency of 27.12 MHz, which is pulsed at a rate, selected by the therapist. It induces non-thermal effect.so it can be dissipated by the circulation before the next pulse occur, thus there are no cumulative thermal effects. Main parameters of PSWT:  Pulse Duration the duration (time) of each ‘ON’ phase.: 20 µs – 400 µs.  Pulse frequency (the number of pulses delivered per second): 15 – 800 Hz  Peak Pulse Power/ The amplitude of the pulse / intensity: 100 – 1000 watts. 6 Physiological effect of PSWT: 1. Increase defense mechanism (increase number of W.B.C.s, and antibodies). 2. Reduction (resolution) of the inflammatory process 3. Reduction of edema. 4. Encourage absorption of hematoma. 5. Stimulate the healing process of wounds. Indications of PSWD: -It’s particularly indicated in the treatment of the acute post traumatic and inflammatory conditions which is contraindicated for continuous SWD due to its thermal effects as: 1. Acute pain, oedema, inflammation 2. Acute sprains and strains 3. Acute Contusions. 4. Acute haematoma. Contraindication of PSWD: 1. High fever. 2. Tumor. 3. Cardiac pacemakers: It is not advisable to apply the SWD in the region of the thorax or the pacemaker control unit as it may interfere with the function of the pacemaker. 4. Patients who are unable to comprehend the therapist's instructions 5. Sever circulatory deficits (ischemic tissues, thrombosis) 6. Recent deep x-ray therapy or other ionizing radiations (in the last 6 months) 7 Suggested treatment doses of PSWT: a. PSWT may or mayn't increase temperature b. It’s suggested that acute conditions should be treated with a low dose, and more chronic conditions with a high dose c. The dose selected as a combination of pulse frequency, pulse duration and pulse power (intensity). d. Acute conditions:  No warmth sensation,  pulse duration: 65 µsec  pulse frequency:100 – 200 pps  Mean power: Less than 3 watts  Treatment duration: 10:15min e. Sub-acute conditions:  Mild warmth sensation  pulse duration: 100 µsec  pulse frequency:800 pps  Mean power: between 2 and 5 watts  Treatment duration: 15min. f. Chronic conditions:  Moderate to vigorous warmth sensation  pulse duration: 200-400 µsec  pulse frequency:800 pps  Mean power: More than 5 watts  Treatment duration: 15-20min. 8 Dangers of SWD 1-Burn: happen due to : a) Excessive heating b) Loss or impaired skin sensation. c) Impaired blood flow. 2 -Electric shock (if patient touches the machine) 3-Fainting: caused by sudden fall in blood pressure. Precautions to avoid dangers: 1-Check all contraindications. 2- Test thermal skin sensation 3- Skin must be dry (avoid sweating) 4- Adequate spacing between electrodes & skin. 5- Don’t allow the patient to touch the machine 6- Don’t increase the intensity unless leads or electrodes are correctly connected to the machine 7- Avoid wearing of any metal (watch, any jewelry or even belt metal….) 9  Types of SWD applications There are two types of SWD applicators: I- Capacitive method II- Inductive method Penetration of SWD: Inductive SWD produce heat in deeper tissues selectively with relatively smaller effects in superficial tissues. Capacitive SWD produce most heat in skin and less heat in deeper structure. I- Types of Electrodes in Capacitive Method: 1- Space plates: is a rigid metal plate encased in a plastic housing or cover. 2- Flexible pads: consists of a malleable metal covered with a thin layer of rubber. 10 II- Types of Electrodes in Inductive Electrodes: - An inductive applicator is made up of a coil or cable through which an alternating electric current flows. This cable may be: 1- Long tubular flexible conductor covered with thick rubber called cable or coil. This may be wrapped round the part to be treated in a spiral manner and is separated from the skin by towel spacing. 2- Monode: Small flat metal coil enclosed in a plastic cover ( drum). 11 3- Diplode or drum electrode: Small flat metal coil enclosed in a plastic drum with two wings attached to a central bar by hinges allowing adjustment of angle of each wing. Factors influencing field distribution: Capacitive Method 1. Spacing of electrode: -Normal spacing of electrodes (2-4cm): Even field distribution. a. Closely spaced electrodes: resulting in superficial heating b. Far spaced electrode: resulting in deep concentration of heating c. Unequal spacing of electrode: resulting in more superficial heat concentrated under closer electrode. 12 2-Size of electrode: - The electrodes should be slightly larger than the treated area: Even field distribution. - The electrodes are too small than treated part: superficial heat - The electrodes are Too big than treated part: heat loss - The electrodes are unequal size: more superficial heat concentrated under smaller electrode. 3-Position of Electrodes relative to tissues -Electrode parallel to the skin surface. - If electrodes not parallel to skin surface, this lead to Superficial heating under closest part of electrodes. 13 4. Tissue type:  Tissues with higher water, contents have high electric conductivity and best heated by SWD.  Metals and sweat are good conductor  Fat is a poor conductive tissue, it affects the penetration of heat to the deeper tissue. Methods and Techniques of Application Shortwave machine with chosen electrodes and its test tube to ensure the machine is working. A=Power Switch B=Timer C=Output Intensity(%max power to patient) D= Continuous or pulsed Control switch 14  Methods of Applying the Electrodes There are two method of application of SWD I- Capacitive field method II- Inductive field method I-Capacitive field method: Positioning of electrodes in capacitive method: 1-Contraplanar application It is used to treat structure on two aspect of the body. Two capacitive electrodes are placed on opposite side of the part to treat deeply placed structures, e.g. joints. The application may be transverse or longitudinal. 2-Coplanar application  It is used to treat structures on one aspect of the body.  Application using two flexible pads or space plates.  Example: Suitable for treating large flat area like back 15 3- Crossfire application  This technique is used for heating the deeply placed organs in the pelvis for the treatment of uterine disorders such as dysmenorrhoea and for air filled cavities such as frontal and maxillary sinuses for the treatment of sinuses. Care must be taken to avoid direct placement over the eye.  In first half of treatment time, electrodes positioned diagonally, then in second half of treatment time the electrodes positions are alternate to another diagonal. II-Inductive field method Mono-planer technique It is used for inductive method. The active electrode is placed over the site of the lesion using: 16   Coil  Monode  Diplode: It permits electrode to be positioned at various angles around the three sides of the body part Practical application of Short Wave Diathermy Guidelines for SWD application 1-The patient should set in a position of optimum comfort and support which allows the area to be treated to be fully exposed. 2- Explain the procedure to the patient. 3- Be certain that there is no contraindication to the short wave diathermy. 17 4-Inspect the area to be treated and palpate carefully to locate the site of the lesion. 5- Skin-test for the area to be treated for discrimination between hot and cold. Using two test tubes one with hot water, the other with cold water. 6- Ensure that there is no metal or sweat on the area to be treated for example hairpins or jewelry. 7- If using flexible pads ensure that no part of the pad is protruding from the spacing and is firmly encased to prevent it from slipping. 8- If using space plates, adjust the position of the electrodes within the covers. 9- Test that the machine is operating by using test tube to ensure the machine is working. 10-Instruct the patient not to move to avoid touching any part of the machine. 12-Warn the patient that he should feel comfortable, warmth and not more, or a bum could result. 13-Turn on the timer to the required treatment time, short-wave diathermy cannot be produced unless the timer is switched on. 15-Turn the intensity control to the lowest intensity setting. Never resonate the machine on higher setting and ask the patient to describe any sensation of warmth felt. 16-After the treatment time has elapsed; the timer automatically cuts out the patient circuit return the machine intensity control to zero. 17-Remove the application and inspect the area treated. 18-Allow the patient to leave after a very brief time. Techniques of application: 1-Application using two space plates (Contra planer Technique): 18   Two electrodes placed parallel to each other on opposite sides of the part to treat deeply placed structures as joints (Knee, ankle, shoulder).  To produce even heat through the tissue the electrodes should be slightly larger than the diameter of the treated part, and evenly spaced approximately 25 mm from the skin.  To concentrate heat on one aspect of the part, the electrodes should be unequal size. The smaller one should be placed over the area where concentration of the heat is required, and the distance should be fixed.  Examples for treatment of the medial collateral ligament of knee joint; the small electrode is applied on medial aspect of knee joint and the larger electrode on the lateral aspect.  Another method of producing concentration of heating is to apply electrodes of equal size. Slightly larger than the part but to use unequal spacing i.e spacing of 25mm should be used over aspect where concentration is required and space of greater than 30 mm on the other electrode. 2. Application using two flexible pads (Co-planer Technique):- 19   When using flexible pad electrodes, wrap them in several layers of toweling or place toweling between flat pads and skin to ensure the required amount of spacing.  The minimum safe amount of pacing is 25 mm. 3- Application using a coil electrode (Mono-planer technique)  Wrapping a cable around the part of the body to be treated, the distance between turns should be approximately 2.5 cm. apart.  Coil must be kept at a distance of 2-3cm from the skin surface to give a sufficient spread of field. This is achieved partly by the rubber insulation of the cable and partly by applying the cable over a minimum of 1 cm thickness towel or other suitable material. 20 4. Application using Monode and Diplode (Mono-planer technique) : Positioned parallel to the skin over the treated area. Distance between skin and drum electrode should be 2-3 cm. Toweling is Essential. 21 5- Combined technique 1. Application using a Combination of flexible pad and a space plate electrode. This application particularly useful for treatment of disorders of ankle joint as Achilles tendinitis (Achilles tendinitis is caused by repetitive or intense strain on the Achilles tendon). Use longitudinal contra planer application with a combination between a flexible pad and a space plate electrode Use a one flexible pad electrode under the foot, and the space plate over the top of the knee. -The line of forces pass parallel through the calf and leg muscle, producing maximum effect of electromagnetic field in the leg muscles. 2. Application using a combination between a flexible pad and a coil.  Useful for the treatment of hip joint problem only or with referred pain down the thigh or for treatment of shoulder joint problem with referred pain in the arm. 22  To localize heating to the joint, the proximal end of the cable is attached to the machine together with the flexible pad and the other end of the cable is insulated.  In case of a shoulder problem with referred pain in the arm or hip problem with referred pain in the thigh; the distal end of the cable is attached to the machine and the proximal end of the cable is insulated. 23 3. Application of two limbs.  Two flexible pads, two space plates are used. It is essential to put a cotton towel between the two limbs to absorb any sweat.  Example for treatment of osteoarthritis of both knees joint. 6- Application using cross fire technique For the treatment of sinuses, space plates positioned diagonally - 1st treating of frontal sinuses with one electrode placed on the lateral aspect of the forehead and another on the other side of the face high on the cheek. For the second half of the treatment the electrodes positions are alternate. - 2nd Treating of the maxillary sinus. With one electrode placed on the lateral part of the cheek and another on the opposite side of the face below the angle of the jaw. For the second half the treatment the the electrodes positions are alternate. -3rd treatment of all sinuses with electrodes one on the lateral part of forehead, the other on the opposite side of the face below the angle of the jaw. N.B: Care must be taken to avoid direct placement of the electrode over the eyes. 24  Case Study A 20 year old female college basketball player in good health sustained a left lateral ankle sprain 2 hours ago. She has no previous history of ankle sprain. Treatment included ice pack, elevation, and compression during last 2 hours. X- Ray has ruled out fracture. Problem: 1- Pain and swelling in left lateral ankle. 2-Unable to bear weight on left lower extremity (LLE) Treatment Procedures 1. Continue treatment with ice, elevation, compression. 2. Cold whirlpool 15 min. or pulsed SWD. Description of Treatment 1. Reduce ankle swelling and pain and increase ankle function. 2. Position patient supine with LL supported and elevated 30 degrees. 3. Apply Pulsed electromagnetic field applicator to within 2.5 cm from edematous ankle tissues. 4. Set Pulsed electromagnetic field controls at mean power less than 3 watts, a pulse duration of 65 µsec, a pulse frequency of 100-200 Hz. 5. Treat 10 minutes daily for 2 weeks or until show significant reduction in swelling and pain. 25