ULTRASONIC THERAPY

Def.: high freq. sound more than the power of human ear capacity (>20000 Hz) NB: 17 – 20000 Hz human ear capacity sound wave.

infra sound wave 17 sound wave 20000 ultra sound wave

Components of apparatus of US & how it works:1) Source of high freq. current ( base oscillating circuit).2) Connected to co-axial cable.3) Connected to transducer circuit ( treating head): electrodes crystals metal plate.

Used in high freq. current

Electrical freq.0.7-1 MHz

4) Linking electrodes inside the transducer circuit convert the high freq. current to crystal quartz or Ba tetanate. ( peizo-electric effect).

5) Change in shape of crystals when subjected to varying potential diff. peizo-electric effect movement of metal front plate production of US waves.

6) Coupling media water, gel, paraffin oil or glycerol.(different efficiency) if absent coupling media reflection of US waves to the apparatus destructing the crystals. Air doesn’t transmit US waves.

7) Application of ttt:1) Test apparatus.2) Determine duration 5 – 10 min3) Determine intensity 0.1 – 3 watt / cm2 .4) Determine freq. 1 – 3 MHz5) Type continuous or pulsed. Waves travel in longitudinal way ( compression & rarefaction)

Uses (of ultrasound):

1. Diagnostic uses of US wave: echo & Doppler2. Uses in surgery: focused therapy ESWL ( extracorporeal

shock wave lithotripsy(,3. in urology ttt of benign prostate hyperplasia.4. Physiotherapy.

Therapeutic effect of US wave on tissues:

• Thermal effect: when US is absorbed it is transformed into thermal energy ( heat). Depth of penetration ( 3 – 5 cm ).Best produced by continuous waves,Pulsed US has less thermal effect used in acute conditions (no need for heat) ↗Bl. Flow ↗absorption of infl. Exudate. Relief pain, relaxation of muscles spasm.

Cont ..• Mechanical effect:caused by pressure changes applied to the tissues by sound waves, is best produced by using pulsed waves. Include: cavitation “large dose”: condition in which bubbles of

gases is produced in tissue due to insonation;• stable harmless or, • transient dangerous» avoided by average

intensity ≤ 3watt/cm2, pulsed US and circular mvt.) micro massage “ small dose “ at cellular level

↘both recent traumatic edema & chronic indurated edema..

cont.: pain relief ( pain gat theory) through stimulation of mechano-R S.C. cells ↘ perception of peripheral pain. Chemical and biological effects:improvement of tissue repair, e.g. bed sores “ by under water therapy. Acoustic streaming, unidirectional flow of tissue component which occur at cell memb. ↗proteins syntheses rate ++ tissue repair. ( can be used in phonophoresis)

Indication : o Musculo-skeletal disorders: articular & extra articular, Acute, subacute or chronic

e.g.:sprain – myalgia and Brachialgia – lumbago –periarthritis – capsulitis – tendinitis.

o Localized conditions:Tennis elbow – C.T.S – Achilles tendinitis – spondylosis and disc prolapse – trigger finger.

o Chronic indurated oedema.o Scar tissue & keloid + contracture after burns: break

fibrous tissues through thermal, mechanical, chemical And biological effects.

Dosage: Intensity of US wave is measured in watts / cm2.

therapeutic doses vary between 0.25 to 3 w/cm2.Lawer intensity below 0.5/cm2 are used for diagnostic proposes High intensity from 4 – 13 w/cm2 are used for destructive purposesTherapeutic intensities vary according to the part treated whether thin or thick, acute or chronic. Duration: between 3 – 15 min, acute cases & small

area take short time for ttt while chronic cases & large areas take a long time.

ttt can be given daily , EOD or even twice weekly.The ttt should start with low doses & increased gradually in accordance with the effect produced.

Preparation for ttt: Eliminate any contraindications. Skin sensation for heat tested before starting ttt. The pt. is informed that he will have a feeling of gentle

warmth or no thing at all. We must report any discomfort or pain especially deep

scatted pain e.g. periosteal pain to reduce dosage.

Application of ttt: US waves require a material medium Good contact & continuous mvt. Are necessary to

prevent over heating & burns. Methods of application: direct contact ( stroking or

circular mvt.) In water bath.

Methods of application: 1) Direct contact : perpendicular head &circular

movement. When the treated surface is regular.2) Under water bath: (degased water)3) Water bag therapy :• uneven surface• skin lesion• traumatic conditions e.g. sprain & strains of

the lig. Tend. or ms. Usually start 24 – 48hs after occurrence, to allows time for healing injured capillaries.

Rubber bag filled with water is put between skin & ttt head.Bag & ttt head are moved on pt. skin with coupling medium between bag & head + skin & bag.

Hazards: • Over dosage• Burns • Cavitation • Damage to crystals when switch on air.

Intensity of US wave depends on: absorption & reflection If ↗ absorption & ↘reflection ↗intensity hazards ( burns , cavitation)

precautions:Over dosage of US has a reverse effect, so the ttt should start with low doses & ↗ gradually.Burns: can be avoided if the doses used within the therapeutic range & proper technique.Cavitation: US with high doses can disrupt the tissues & produce cavitation of tissues.Damage to the crystal: if The apparatus is turned to the “ ON “ position while the treating head is in air. The wave are reflected back to the crystals, this may break the crystal.

contraindication: Absolute:1. Brain tissue.2. Spinal cord. laminectomy ( only paraspinal application)

3. Ovary and testes.4. Vascular dis. ( ischemia - DVT)5. Pace maker ( cardiac pt.)6. Prosthesis ( artificial knee)7. Pregnancy (therapeutic not diag. US)8. Radiotherapy never applied on

immediate area for at least 6ms.9. Tumors US ++ growth & metastases.10. Acute sepsis.

relative:1. Hypothesia pulsed.2. Subacute & chronic ischemia.3. skin lesions Not infected.4. children (risk to growing epiphysis)

0.1 – 0.5 watt/cm2 , pulsed.NB: avoide on bony prominence periosteal pain due to reflection of US wave over periosteal double intensity.