Ultrasound

Sonicator 740x

Ultrasound functions to speed up tissue healing, decrease swelling, decrease pain, and increase tissue extensibility.  It does this through mechanical and thermal (heating) mechanisms.

Mechanical: these benefits arise due to two separate phenomenon 

Cavitiation:
occurs due to pressure changes, gas bubbles oscillate (compress with peak of wave & expand with valley)

Acoustic (Micro) Streaming:
one directional motion of fluid caused by sound wave 

Mechanical Benefits include:

• improves cell membrane permeability (opens protein channels for exit and calcium channels to enter                     ­ 
  
• increases macrophage activity
  
• causes stronger more elastic connective tissue              ­ 
  
• increases cytokines                               ­ 
  
• increases blood flow                              ­ 
  
• increases fibroblast activity                  
  
• reduces edema formation        
  
• can also help drive topical medicine into the tissues                     

Thermal: (same as superficial heating but deeper)

• increases nerve conduction velocity   
  
• increases extensibility of collagen based structures 
  
• increases blood flow
  
• enhanced adhesion of leukocytes                      ­ 
  
• increased bradykinin                           ­ 
  
• increased metabolic activity       
  
• reduces spasm
  
• increases venous & lymphatic return 
  
• increases oxygen dissociation off hemoglobin
  
• improves strength & function of collagen tissue
  
• reduces pain: decreases mechanical pressure, reduces spasm (decreased firing of gamma & alpha motor neurons), decreased ischemia