Therapeutic ultrasound

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Therapeutic ultrasound
ICD-10-PCS6A7
ICD-9-CM00.0

Therapeutic ultrasound refers generally to any type of ultrasonic procedure that uses

cancer therapy, and ultrasound assisted thrombolysis[1][2]
It may use focused ultrasound or unfocused ultrasound.

In the above applications, the ultrasound passes through human tissue where it is the main source of the observed biological effect (the oscillation of abrasive dental tools at ultrasonic frequencies therefore do not belong to this class). The ultrasound within tissue consists of very high frequency sound waves, between 800,000 Hz and 20,000,000 Hz, which cannot be heard by humans.

There is some evidence that ultrasound is more effective than placebo treatment for treating patients with arthritis pain,[3] a range of musculoskeletal injuries[4] and for promoting tissue healing.[5]

Medical uses

Relatively high power ultrasound can break up stony deposits or tissue, accelerate the effect of drugs in a targeted area, assist in the measurement of the elastic properties of tissue, and can be used to sort cells or small particles for research.

  • Focused high-energy ultrasound pulses can be used to break calculi such as kidney stones and gallstones into fragments small enough to be passed from the body without undue difficulty, a process known as
    lithotripsy
    .
  • Focused ultrasound sources may be used for cataract treatment by phacoemulsification.
  • Ultrasound can
    Magnetic Resonance Imaging (MRI)
    ; the combination is then referred to as Magnetic resonance-guided focused ultrasound.
acoustic targeted drug delivery
.

There are three potential effects of ultrasound. The first is the increase in blood flow in the treated area.[citation needed] The second is the decrease in pain from the reduction of swelling and edema[citation needed]. The third is the gentle massage of muscle tendons and/ or ligaments in the treated area because no strain is added and any scar tissue is softened[citation needed]. These three benefits are achieved by two main effects of therapeutic ultrasound. The two types of effects are: thermal and non thermal effects. Thermal effects are due to the absorption of the sound waves. Non thermal effects are from cavitation, microstreaming and acoustic streaming.[1]

Cavitational effects result from the vibration of the tissue causing microscopic bubbles to form, which transmit the vibrations in a way that directly stimulates cell membranes. This physical stimulation appears to enhance the cell-repair effects of the inflammatory response.

History

The first large scale application of ultrasound was around World War II. Sonar systems were being built and used to navigate submarines. It was realized that the high intensity ultrasound waves that they were using were heating and killing fish.[8] This led to research in tissue heating and healing effects. Since the 1940s, ultrasound has been used by physical and occupational therapists for therapeutic effects.

Physical therapy

Ultrasound is applied using a transducer or applicator that is in direct contact with the patient's skin. Gel is used on all surfaces of the head to reduce friction and assist transmission of the ultrasonic waves. Therapeutic ultrasound in physical therapy is alternating

MHz. Maximum energy absorption in soft tissue occurs from 2 to 5 cm. Intensity decreases as the waves penetrate deeper. They are absorbed primarily by connective tissue: ligaments, tendons, and fascia (and also by scar tissue).[9]

Ultrasound has been used to help physical therapists navigate transcutaneous modalities that aim to stimulate specific muscles beneath the skin; modalities such as

impingement syndrome, bursitis, rheumatoid arthritis, osteoarthritis, and scar tissue adhesion. There is no evidence to support the use of ultrasound for the treatment of low back pain,[11] and current clinical guidelines recommend that ultrasound is not used for this condition.[12] In a critical review, it was demonstrated that therapeutic ultra sound was effective in improving pain, function, and cartilage repair in knee osteoarthritis. Another systematic review and meta-analysis of low-intensity pulsed ultra sound on knee osteoarthritis a significant effect on pain reduction and knee functional recovery was demonstrated.[13] Ultrasound used for calcific tendonitis had a positive short term effect. For the long term, there was no significant difference with ultrasound use. This shows that for pain relief and short-term treatment ultrasound can be an effective treatment for Calcific Tendonitis[14] A review with five small placebo‐controlled trials from 2011, did not support the use of ultrasound in the treatment of acute ankle sprains and the potential treatment effects of ultrasound appear to be generally small and of probably of limited clinical importance, especially in the context of the usually short‐term recovery period for these injuries.[15] However, therapeutic ultrasound is reported to have beneficial effects in sports injuries pain relief, edema control, and range of joint motion, possibly by increasing pain thresholds, collagen extensibility, reducing edema, and therefore inflammation, muscle spasms, and joint stiffness.[13] A meta-analysis found that ultrasound therapy is effective in reducing pain, increasing ROM, and reducing WOMAC functional scores in patients with knee osteoarthritis.[3]

Knee Oseteoarthritis

According to recent research, therapeutic ultrasound has not shown any significant improvement for chronic low back pain, chronic neck pain, and hip pain in combination with other physiotherapeutic techniques.[16][17] However, the most conclusive evidence to support therapeutic ultrasound use is seen with its use in patients with knee osteoarthritis. Knee osteoarthritis affects approximately 250 million people worldwide.[18] While there is no known cure, therapeutic regimens are often used to intervene with the diseases chronic symptoms.[18] In a systematic review of 15 studies, patients who received ultrasound treatments were compared to those who received a placebo treatment. The evidence demonstrated that therapeutic ultrasound significantly relieved pain, increases range of motion, and reduced WOMAC functional scores in patients with knee osteoarthritis when compared to the placebo group.[3] In a separate meta-analysis, it reinforced the use of therapeutic ultrasound by deeming it as a safe non-pharmalogical treatment option that may provide additional pain relief as well as functional improvement when used secondarily to therapy in patients with knee osteoarthritis.[18]

Research tools

Research

  • Using ultrasound to generate cellular effects in soft tissue has fallen out of favor as research has shown a lack of efficacy[20] and a lack of scientific basis for proposed biophysical effects.[21]
  • According to a 2017 meta-analysis and associated practice guideline,
    Low intensity pulsed ultrasound should no longer been used for bone regeneration because high quality clinical studies failed to demonstrate a clinical benefit.[22][23]
  • An additional effect of low-intensity ultrasound could be its potential to disrupt the blood–brain barrier for drug delivery.[24]
  • Transcranial ultrasound is being tested for use in aiding
    tissue plasminogen activator treatment in stroke patients in the procedure called ultrasound-enhanced systemic thrombolysis
    .
  • Ultrasound has been shown to act synergistically with antibiotics in killing bacteria.[25]
  • Ultrasound has been postulated to allow thicker eukaryotic cell tissue cultures by promoting nutrient penetration.[26]
  • Long-duration therapeutic ultrasound called sustained acoustic medicine is a daily slow-release therapy that can be applied to increase local circulation and theoretically accelerates healing of musculoskeletal tissues after an injury.[27] However, there is some evidence to suggest this may not be effective.[20]
  • Ultrasound has been shown to contribute to improvement of muscular strength of the forearm muscles and humerus muscles and an increase in range of motion in the elbow joint in flexion and outward rotation when accompanied with therapeutic exercise as well as a reduction in pain in men ages 30-40 with tendinitis[28]

See also

References

  1. ^
    S2CID 31178343
    .
  2. ^ "Therapeutic Ultrasound: A Promising Future in Clinical Medicine". Archived from the original on October 12, 2007.
  3. ^
    S2CID 199452082
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  4. PMID 34207333
    .
  5. PMID 34116673
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  6. PMID 21197390
    .
  7. S2CID 31498698
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  8. ^ Woo J. "A short History of the development of Ultrasound in Obstetrics and Gynecology". esource Discovery Network, University of Oxford. Retrieved March 12, 2012.
  9. ^ Watson T (2006). "Therapeutic Ultrasound". herapeutic Ultrasound on the web. Archived from the original on 2007-08-21.
  10. PMID 31023858
    .
  11. PMID 32623724
    .
  12. OCLC 1198756858.[page needed
    ]
  13. ^
    S2CID 221358210
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  14. S2CID 4614904
    .
  15. PMID 21678332
    .
  16. PMID 31095336
    .
  17. PMID 30649460
    .
  18. ^
    PMID 34535411
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  19. S2CID 209164551
    .
  20. ^
    PMID 11444997
    .
  21. PMID 11444998
    .
  22. PMID 28348110
    .
  23. PMID 28228381
    .
  24. PMID 21465543
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  25. PMID 15070512
    .
  26. PMID 12790676
    .
  27. PMID 26509683
    .
  28. ProQuest 2604880642
    .

External links
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