Treatment - Ultrasound

Question 1

What is Therapeutic Ultrasound

Answer 1

> Providing mechanical energy to cell membrane via soundwaves (at an inaudible frequency - below 20Hz)

• Changes behaviour of cell membrane (excites membrane so excites cell)
• Requires coupling gel to avoid reflection off skin

Question 2

Absorption levels

Answer 2

> Greater absorption if higher protein content
- Best absorption is in tendon/ligament/fascia/joint capsule/scar tissue
(bone + cartilage are the best absorbers)
+ greater absorption in more superficial tissues

Question 3

Theory - cellular level

Answer 3

> Pro-inflammatory mediator
Thermal treatment (not used in UK)
- heats specific tissues to ~45 degrees to trigger hyperaemia (increased blood supply)
Non- thermal
- Cavitation - formation of gas filled voids in tissue *STABLE - growing due to accumulation of dissolved gas which aids acoustic streaming = therapeutic
*UNSTABLE - bubbles collapse which releases energy to cell = may damage tissue
- Acoustic streaming - fluid moves in circular fashion near vibrating structure (membrane/cavitations)
*affects permeability + movement rates (Na+ changes affects membrane potential and Ca2+ changes alters mechanism of transport so enzyme control is affected)

Question 4

Theory - affect on healing

Answer 4

> ultrasound increases efficiency of healing
Inflammatory phase - stimulates release of inflammatory mediators (mast cells/macrophages /phagocytes)
Proliferative phase - increased collagen/protein synthesis (targets fibroblasts/myoblasts/endothelial cells)
Remodelling phase - increased type 1 collagen synthesis + alignment of fibres

*poor evidence to support this however may aid fracture non/mal-union

Question 5

Method

Answer 5

> Test hot/cold sensation 1st

> Pulse ratio = time on/time off
- acute = 1:3 or 1:4
- chronic = continuous or 1:1
(added together in application time ie 1:4 = 5)

> Frequency = depth of penetration

• Superficial (<2cm): 3Mhz
• Deep (2-6cm): 1Mhz

> Intensity = energy supplied

• acute = 0.1-0.3 W/cm2
• chronic = 0.3-0.8W/cm2

> Application time
- Frequency x Pulse ratio x Treatment head (how many times will it fit over treatment area)

• Keep head moving always (non-thermal treatment)
• lowest intensity required to get therapeutic response

Question 6

Contraindications

Answer 6

> Cognitive difficulty
Pregnancy - not over uterus
Active Cancer/growth disorder/ infection
Recent bleeding/haemorrhage
haemophiliacs without factor replacement
vascular abnormalities (DVT/embolism/PVD)
Sensitive organs (eyes/gonads)
Anterior of neck
Devitalised skin/acute skin conditions
loss of sensation/circulation - test first
*be careful over pacemakers or metal/electric implants especially with continuous pulse