LIPUS-Low Intensity Pulsed Ultrasound

LIPUS is a form of mechanical energy which is transmitted through & into the living tissue as acoustic pressure waves above the human audible range.

Hypothesis: Micro-mechanical strains produced in biological tissues   >Biochemical events   >stimulate Fracture healing

EFFECTS: 1. causes Osteoblasts, Fibroblasts & Monocytes induced cell proliferation-differentiation   >Bone-formation.
2. Angiogenesis- through release of TGF-β, b-FGF, IL-8, PGE2 & VEGF.
3. decrease in Pro-inflammatory cytokines like IL-6, TNF-α.

Timing of Use: ~Useful in Inflammatory & Repair phase
~does not affect remodelling phase of fracture-healing.

Mechanism of Action: not clear
Different Hypothesis:-

  1. Motion caused by pulsed waves of LIPUS at both fractured ends; the motion occurs at nanometric scale  >to stimulate molecular & cellular pathways involved in healing.
  2. Cavitation & Acoustic Sreaming: Pulsating sounds from LIPUS   >Accumulation of Gas Bubbles within Cells & tissues   >creats a CAVITY to support Acoustic streaming
    CAVITY–> Stable & Unstable
  3. Stable Cavitation   >Turbulence/Circular flow of tissue around bubbles   >Increases cell-permeability   >Rise in BP at the site of injury   >Increased gas-exchange & nutrient-delivery
  4. Unstable Cavitation   >Burst of bubbles   >Energy released   >Stimulate surrounding tissues

USES: 1. Delayed Union, 2. Non-union, 3. Osseointegration of Implants.