Shortwave Diathermy (swd) — How It Works & What It Treats

Shortwave diathermy is a therapeutic modality that uses high-frequency alternating currents to generate heat in the body's tissues. It is commonly used to produce deep heating in joints and soft tissues.

High-frequency electromagnetic energy of the shortwave therapy passes through the patient's body and is absorbed by the body tissues. Since body tissue contains ions, the electromagnetic energy causes the ions to move in various directions, creating friction between the moving ions and surrounding tissues. This decreases joint pain and enhances soft tissue healing.

Diathermy is a part of a complete physiotherapy regimen. The frequency and length of the treatments vary.

Frequency: Shortwave diathermy uses a frequency ranging from 3 to 30MHz Usually a frequency of 27.12 MHz and a wavelength of 11 meters is used. Currents of such high frequencies do not stimulate sensory or motor nerves nor do they produce any muscle contraction. Shortwave diathermy can either be
1: Continuous shortwave diathermy (CSWD).
2: Pulsed shortwave diathermy (PSWD).

Continuous short-wave diathermy: Has a thermal effect more than pulsed, so it is generally used for its thermal effects whereas Pulsed short-wave diathermy has athermal effects. Shortwave diathermy uses high-frequency electromagnetic energy to generate heat, in pulsed or continuous energy waves.

Electrodes: The current is applied to the patient by a heavy, flexible, insulated cable which is used as the electrode and is coiled about or around the patient’s part to be treated.
There are two methods of application of electrode pads,
1: Contra planar.
2: Coplanar.

1. Contra planar electrode placement: The two electrodes are placed in two different planes, therefore it is called contra planar. the two pads sandwich the treating body part between them.

2. Coplanar electrode placement: In contra planar arrangement, the pads are placed side by side on the same plane. This is used to treat large body parts such as the upper back. lower back. The electrodes should not be placed too close as the wave path does not go deeper.

The choice between pulsed and continuous frequency, as well as the intensity of Shortwave Diathermy (SWD), is influenced by the therapeutic goals and the patient's condition.

Continuous vs. Pulsed Mode:
1. Continuous mode: Generally used for deep tissue heating, promoting blood flow, and managing chronic conditions.

2. Pulsed mode: Often preferred for acute injuries or conditions where intermittent thermal effects are desired. It can help control inflammation and reduce pain.

Frequency:
27.12 MHz is common for SWD: It allows for deeper tissue penetration. However, lower frequencies may be chosen for certain cases.
Higher frequencies: Penetrate tissues more effectively but may cause more surface heating.
Lower frequencies: Penetrate less but also generate heat on the surface.

Intensity:
Start low and gradually increase: Initiate with a lower intensity to assess the patient's tolerance and adjust based on their response.
Consider patient feedback: Monitor for signs of discomfort or excessive heating and adjust intensity accordingly.

Treatment Duration:
The session duration varies but is typically around 15 to 30 minutes. The therapist will closely monitor the patient during the session.

Sensation and Heating:
Patients may experience a mild warming sensation or tingling during the session. The degree of heating depends on the intensity and mode chosen. Patients are encouraged to communicate any discomfort or unusual sensations to the therapist during the session.

Short Wave Diathermy uses two condenser plates that are positioned on either side of the body part to be treated. Another form of application is by using induction coils that can be molded to fit the part of the body under treatment. As the electromagnetic waves travel through the body tissues between the condensers or the coils, they convert them into heat. Heat and depth of penetration depend on the resistance and absorption properties of the tissues that the waves encounter.
Heat increases the diameter of the blood vessels, thus increasing blood circulation and removing waste products. Also increases the nutrient supply in the affected area and gives relief from pain and also reduces muscle spasms, helps to relax tight muscles, and improves the range of motion.

Shortwave diathermy (SWD) can be used in conjunction with other physiotherapy modalities to enhance their effectiveness. The known benefits of SWD include:
1: Reduces pain and inflammation,
2: Improves range of motion,
3: Promote healing in the affected area.
4: Reduces muscle spasm and stiffness.

Alternatives to Shortwave Diathermy (SWD) therapy depend on the specific condition being treated. Some alternatives include:

Ultrasound Therapy:
Uses sound waves to generate heat and promote healing. It's often employed for soft tissue injuries and musculoskeletal conditions.

Thermotherapy:
Hot packs can be applied to the affected area to manage pain and promote circulation.

Infrared Therapy:
Utilizes infrared light to penetrate tissues, providing heat and promoting healing. It can be used for various musculoskeletal conditions.

Laser Therapy:
It involves the use of focused laser light to stimulate cellular activity and promote tissue healing. It's often used for soft tissue injuries.

Shortwave diathermy can be used to control pain and edema. Shortwave diathermy (SWD) is commonly used to treat a variety of musculoskeletal conditions, including:
1: Sprain and Strain.
2: Frozen shoulder.
3: Degenerative joint disease (OA).
4: Joint stiffness.
5: Tenosynovitis.
6: Arthritis.
7: Tendinitis.
8: Bursitis.
9: Myofascial pain.
10: Lumbar pain.
11: Tennis elbow, etc.

To apply Shortwave diathermy treatment safely, physiotherapists must know the contraindications for the use of such equipment. There are some contraindications of SWD, a few of them are mentioned below:
1: Certain skin conditions,
2: Pregnancy,
3: Patients who are taking blood-thinning medications,
4: Cancer,
5: Severe/excessive edema,
6: Metallic implant,
7: Cardiac pacemaker,
8: Over wet dressing,
9: Acute inflammation,
10: Infected open wound,
11: Impaired thermal sensation,
12: Recent radiotherapy,
13: Pregnancy,
14: Severe cardiac abnormality,
15: Anesthetic area,
16: Tuberculosis,
17: Reproductive organ.

Shortwave diathermy (SWD) therapy is a safe and effective treatment option for musculoskeletal conditions. But there are some risks associated with the use of SWD therapy, like SWD therapy generates heat, which can cause burns if the treatment is not properly rendered or if the patient has certain skin conditions, and prolonged or excessive heat exposure from SWD therapy can cause tissue damage, usually, in patients with certain medical conditions and certain medications, some patients may experience an allergic reaction to the materials used in the SWD treatment, like gel or pads. SWD therapy generates electromagnetic waves, which can interfere with certain medical devices such as pacemakers, and also should not be used in patients with certain types of cancer, as the heat generated by SWD can exacerbate these conditions.

Once the machine is switched on, the physiotherapist should keep at least 1 meter from the machine, leads, and electrodes. For safety purposes:
1: Ensure the earthing of the machine.
2: The machine and the electrodes should be properly connected.
3: Patients should not be allowed to touch the unit.
4: Check contraindications.
5: The patient should be properly positioned.
6: Do not place it over the wet area.
7: Check the thermal sensitivity.
8: Remove metal if wearing.
9: Skin surfaces should be separated by a towel.
10: Wait for 2-3 minutes after setting.