Therapeutic ultrasound

Therapeutic ultrasound
Intervention
ICD-10-PCS 6A7
ICD-9-CM 00.0

Therapeutic ultrasound refers generally to any type of ultrasonic procedure that uses ultrasound for therapeutic benefit. This includes HIFU, lithotripsy, targeted ultrasound drug delivery, trans-dermal ultrasound drug delivery, ultrasound hemostasis, cancer therapy, and ultrasound assisted thrombolysis[1] [2] It may use focused ultrasound (FUS) or unfocused ultrasound.

Ultrasound is a method of stimulating the tissue beneath the skin's surface using very high frequency sound waves, between 800,000 Hz and 2,000,000 Hz, which cannot be heard by humans.

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.[3] 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 compression and rarefaction of sound waves with a frequency of >20,000 cycles/second. Therapeutic ultrasound frequency used is 0.7 to 3.3 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).[4]

Conditions for which ultrasound may be used for treatment include the follow examples: Ligament Sprains, Muscle Strains, Tendonitis, Joint Inflammation, Plantar fasciitis, Metatarsalgia, Facet Irritation, Impingement syndrome, Bursitis, Rheumatoid arthritis, Osteoarthritis, and Scar Tissue Adhesion.

Benefits of ultrasound

There are three primary benefits to ultrasound. The first is the speeding up of the healing process from the increase in blood flow in the treated area. The second is the decrease in pain from the reduction of swelling and edema. The third is the gentle massage of muscles tendons and/ or ligaments in the treated area because no strain is added and any scar tissue is softened. 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.

Effectiveness of therapeutic ultrasound for pain, musculoskeletal injuries, and soft tissue lesions remains questionable.[5][6]

Study has proven that Ultrasound helps in enhancing the metabolic activities of cells. Thus, ultrasound treatment helps in tissue repair, especially in soft tissue injuries.

Biomedical applications

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.

Enhanced drug uptake using acoustic targeted drug delivery (ATDD).

See also

References

  1. 1.0 1.1 1.2 1.3 Steven Mo, Constantin-C Coussios, Len Seymour & Robert Carlisle (2012). "Ultrasound-Enhanced Drug Delivery for Cancer". Expert Opinion on Drug Delivery 9 (12): 1525. doi:10.1517/17425247.2012.739603.
  2. Therapeutic Ultrasound: A Promising Future in Clinical Medicine
  3. Woo, Joseph. "A short History of the development of Ultrasound in Obstetrics and Gynecology". esource Discovery Network, University of Oxford. Retrieved March 12, 2012.
  4. Watson, T. (2006). "Therapeutic Ultrasound". (see here for a pdf version with the author and date information)
  5. A Review of Therapeutic Ultrasound: Effectiveness Studies
  6. Wilkin, H. D., et al. (2004). Influence of Therapeutic Ultrasound on Skeletal Muscle Regeneration Following Blunt Contusion. International Journal of Sports Medicine, 25, 73-77.
  7. Lewis Jr., George K.; Olbricht, Willam L.; Lewis, George (2008). "Acoustic enhanced Evans blue dye perfusion in neurological tissues". Proceedings of Meetings on Acoustics 2 (1). p. 020001. doi:10.1121/1.2890703.
  8. Lewis, George K.; Olbricht, William (2007). "A phantom feasibility study of acoustic enhanced drug delivery to neurological tissue". p. 67. doi:10.1109/LSSA.2007.4400886. ISBN 978-1-4244-1812-1. |chapter= ignored (help)
  9. "Acoustics and brain cancer".
  10. Valma J Robertson, Kerry G Baker (2001). "A Review of Therapeutic Ultrasound: Effectiveness Studies". Physical Therapy 81 (7): 1339–50. PMID 11444997.
  11. Kerry G Baker; Robertson, VJ; Duck, FA (2001). "A Review of Therapeutic Ultrasound: Biophysical Effects". Physical Therapy 81 (7): 1351–8. PMID 11444998.
  12. Toothsome research may hold key to repairing dental disasters – ExpressNews – University of Alberta. Expressnews.ualberta.ca. Retrieved on 2011-11-13.
  13. Fotios Vlachos,Yao-Sheng Tung,Elisa Konofagou,Permeability Dependence Study of the Focused Ultrasound-Induced Blood–Brain Barrier Opening at Distinct Pressures and Microbubble Diameters Using DCE-MRI,Magnetic Resonance in Medicine,2011,vol.66,p.821-830
  14. Carmen, JC; Roeder, BL; Nelson, JL; Beckstead, BL; Runyan, CM; Schaalje, GB; Robison, RA; Pitt, WG (2004). "Ultrasonically enhanced vancomycin activity against Staphylococcus epidermidis biofilms in vivo". Journal of biomaterials applications 18 (4): 237–45. doi:10.1177/0885328204040540. PMC 1361255. PMID 15070512.
  15. Pitt WG, Ross SA (2003). "Ultrasound increases the rate of bacterial cell growth". Biotechnol Prog. 19 (3): 1038–44. doi:10.1021/bp0340685. PMC 1361254. PMID 12790676.
  16. Rigby, J., R. Taggart, K. Stratton, G.K. Lewis Jr, and D.O. Draper, Multi-Hour Low Intensity Therapeutic Ultrasound (LITUS) Produced Intramuscular Heating by Sustained Acoustic Medicine. J Athl Train, 2015.

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