Ultrasound

Injury type: Acute/ Chronic

Category: Allied Health Options

Rating: No research

What is it?

Therapeutic ultrasound is a machine that administers high-frequency sound waves (ultrasound) to connective tissues such as muscles, ligaments and tendons. It is different from diagnostic ultrasound that is used to ‘see inside’ the body. The frequency of therapeutic ultrasound is typically 1-3 MHz. The sound waves pass through tissue with high water or low protein content, and tend to bounce off cartilage and bone. It is used to speed up the healing process and assist in pain relief. Ultrasound is administered via direct contact of the ultrasound head with the skin and the use of a gel to help conduct the sound waves. Ultrasound may also be provided in a water bath (ideal for small body parts such as fingers/toes), and in this situation the ultrasound head does not have to be in direct contact with the skin to work as the water acts as the conductor. Ultrasound is usually administered by a qualified professional in their clinic; however there are some portable units available for home or non-clinic use.

How does it work?

Therapeutic ultrasound is thought to have two types of benefits: thermal and non-thermal. Thermal effects are brought about by energy absorbed from the sound waves heating the tissue. If the tissue is heated to 40-45ºC (104-113ºF), it can enter a state of hyperaemia (increased blood flow), which speeds healing and reduces chronic inflammation. Heating may also increase the extensibility or elasticity of connective and scar tissues. Non-thermal or cavitational effects may result from the vibration of the tissue causing microscopic air bubbles to form, which transmit the vibrations in a way that directly stimulates cell membranes. This physical stimulation may enhance the ability of cells to repair themselves.

Is it effective?

No new research has been conducted to evaluate the effectiveness of ultrasound for the treatment of whiplash. A recent systematic review¹ which updated the evidence on passive physical modalities (including ultrasound) for the treatment of whiplash revealed no new research studies. Based on historical and current evidence, the authors concluded that ultrasound is ‘likely not helpful/ not worth considering’ for the management of persistent grades I-II whiplash. Multiple clinical practice guidelines² for the management of whiplash report conflicting recommendations for the use of ultrasound for whiplash, ranging from ‘insufficient evidence’ to ‘recommended’ or ‘not recommended’.

Are there any disadvantages?

If the ultrasound device is held still for prolonged periods whilst in contact with the skin it can cause damage to the underlying tissues, therefore the ultrasound head must be moved continuously. Ultrasound should therefore only be applied by a qualified professional. It should be applied on a pulsed setting if an injury is less than 3 days old so that it does not cause any heating in the tissues as this can increase swelling in the area.

Where do you get it?

Ultrasound is typically applied in a clinical setting by a Physiotherapist or other health professional such as a Doctor, Chiropractor or Osteopath. There may be some situations where portable ultrasound machines are available to hire or purchase for personal use.

Recommendations

Currently there is no evidence to support the use of ultrasound following whiplash. More up-to-date research is needed before concrete recommendations can be made.