Ultrasound therapy uses sound waves to cause stimulation of tissues under the skin surface. The sound waves have a high frequency (between 800,000Hz to 2,000,000Hz) which causes movement in cellular molecules. It promotes blood circulation, prevents swelling and edema, and reliefs chronic pains. An ultrasound sound works with a gel spread on the skin as it transmits the sound waves from the ultrasound head.
LLLT is different from ultrasound: it does not require a gel, and is used directly on the skin without a gel application. An ultrasound has limitations on its effectiveness and a range of applications compared to LLLT. An ultrasound should not be used on acute injuries, plates, pins or bony prominences. Physiotherapists prefer the LLLT over the ultrasound when it comes to its use on the above mentioned areas, which the LLLT performs effectively.
Ultrasound therapy works on closed wounds only. It has both thermal and non-thermal properties, which makes it therapeutically beneficial. It generates warmth at high intensities, and it is thus useful in muscoskeletal conditions, such as spasms and changes the model of wound healing phase, to improve the outcome of wound healing or the scar.
LLLT employs low-level lasers to alter the process of healing at the level of the cell, even on an open wound. It reduces inflammation by lowering the quantity of enzymes and chemicals in the cell linked to inflammation and pain. It also increases the speed of wound healing by increasing cell division and cell proliferation.
Through various researches, it is possible to compare the effects of laser and ultrasound on wound healing. Pressure sores are common in patients who have spinal cord injuries due to the immobilizing effect of the condition.