Therapeutic Ultrasound Sports Medicine Therapeutic Ultrasound

Discussion Scenario A high jumper from the track team has been experiencing R knee pain. She visited the doctor and brought back a note clearing her for activity. She also brought back a script for ultrasound treatments 3 times a week. She asks you what ultrasound is used for and why she needs to do it. What would you tell the athlete? Be prepared to share your responses.

Objectives Explain how ultrasound works List the indications and contraindications for using ultrasound Justify the need for an ultrasound treatment

Terminology Therapeutic ultrasound – a modality using sound waves to penetrate tissues for healing; can be thermal or non- thermal.

Therapeutic Ultrasound Ultrasound machine Sound head

How Ultrasound Works The ultrasound unit contains a generator, which provides an electrical current that is transmitted to a crystal located in the sound head. The electrical current causes the crystal to vibrate, producing a high-frequency sound wave. Humans can hear 18,000 – 20,000 Hz (cycles/second) Ultrasound is either 1 million (1MHz) or 3 million (3MHz) The high-frequency sound waves generate heat energy.

How Ultrasound Works (cont.) The sound wave is absorbed by tissues with a high protein content (tendons, ligaments, joint capsules, and muscle). The sound wave is poorly absorbed by bone tissue; the majority is reflected or refracted. https://www.youtube.com/watch?v=aNL0cbmHiZM https://www.youtube.com/watch?v=Q9By8MIx3mc

Ultrasound Parameters Frequency: cycles per second (Hz) 1 MHz – heats tissues from 2 to 5 cm deep 3MHz – heats superficial tissues Intensity: the amount of energy transferred to the tissues, expressed in W/cm² (ranges from 0.1 to 5.0 W/cm²) Continuous or pulsed sound beam: Continuous output produces thermal effects Pulsed output produces mechanical effects for tissue healing

Ultrasound Parameters Duty cycle: the amount of time the ultrasound is on 20% means it’s on 1 out of every 5 seconds 100% means it’s on continuously Treatment area: should be about twice the size of the sound head Treatment length: usually 5-10 minutes

Ultrasound Guidelines A coupling agent is required to transmit the sound waves into the tissue (either cream, gel or water) The sound head must be moved about 2-4 cm per second to prevent burning Requires constant supervision by ATC

Indications for Ultrasound Acute injuries (tissue healing, non-thermal effects) Chronic injuries Muscle strains Ligament sprains Muscle spasm Tissue tightness Scar tissue

Contraindications for Ultrasound Areas with sensory or circulatory deficits Over fractures or open growth plates Over tumors Over artificial joints Over heart, eyes, brain, spinal cord Over reproductive organs Over abdomen during pregnancy Over herniated discs Acute injuries (in continuous heat setting)

Ultrasound can safely be used: 1. To shrink tumors 2. Over open growth plates 3. Over the brain or spinal cord 4. Over scar tissue 5. For acute injuries 1. Hand signals: thumbs up or thumbs down to indicate agreement or disagreement use fingers to indicate a number selection such as “Which is the correct solution one, two or three?” teacher gives feedback to the students

Ultrasound can be used for all of the following except: 1. Ligament sprains 2. Acute injuries 3. Chronic injuries 4. Muscle tightness 5. Muscle spasms 1. Hand signals: thumbs up or thumbs down to indicate agreement or disagreement use fingers to indicate a number selection such as “Which is the correct solution one, two or three?” teacher gives feedback to the students

Ultrasound is contraindicated in which area? 1. Heart 2. Brain 3. Eyes 4. Reproductive organs 5. All of the above 1. Hand signals: thumbs up or thumbs down to indicate agreement or disagreement use fingers to indicate a number selection such as “Which is the correct solution one, two or three?” teacher gives feedback to the students

Sample Treatments* Condition Frequency Duty Cycle Deep muscle adhesion 1 MHz 100% Deep bursitis 20-50% Superficial scar 3 MHz Superficial tendinitis https://www.youtube.com/watch?v=qimTPidmIMQ

Ticket Out the Door What is the therapeutic difference between continuous ultrasound and pulsed ultrasound? What is the difference between using a frequency of 1 MHz and a frequency of 3 MHz?