Laser therapy uses the effects of the energy generated by laser light sources (acronym of Light Amplification by Stimulated Emission of Radiation) which, by penetrating into the tissues, induce biochemical reactions at a cell membrane level.
In particular, it has been observed that if laser light is administered in the right doses, a stimulation of the cellular functions is obtained, above all in the cells that have functional deficits.
The main effects of laser therapy include:
- an increase in blood flow, i.e. vasodilatation of capillaries and arteries with consequent increase in local heat
- biostimulation, which concerns the regeneration of tissues, stimulation of protein synthesis, stimulation of ATP production and electrolyte exchange in intra and extra cellular environments, stimulation of fibroblasts to perform mitosis and increase the production of collagen and elastin
- an anti-inflammatory effect
- an antiedematous effect, i.e. an increase in lymphatic drainage
- an analgesic effect
It is possible to classify different types of interactions between lasers and tissues:
- Photophysics interactions: the laser’s monochromaticity is utilised to excite the target chromophore (hemoglobin, myoglobin, water, etc.)
- Photochemical interactions: the absorption process is followed by a series of chemical reactions that alter the biological substrate
- Photothermal interactions: due to the conversion of energy used in heat
- Photomechanical interactions: by focusing ultra-short pulses, with high peak power, on very small volumes, actual mechanical vibrations are obtained
Operating mode and power
The laser beam can be output in continuous or pulsed mode. In both modes cell biostimulation processes are triggered with a corresponding increase in ATP production.
In continuous mode output, the processes of tissue regeneration are triggered, accelerating the recovery time of the movement.
It is particularly indicated in conditions presenting deep injuries.
Main applications: degenerative conditions (arthrosis), osteoarticular conditions and deep muscle-ligament injuries.
Pulsed mode triggers biostimulation with lower thermal impact than continuous mode.
It is therefore particularly indicated for inflammatory conditions.
Main applications: lumbago, sciatica, knee pain, oedema, effusions, conditions in the acute phase.
Power (measured in Watts) represents the amount of energy that can be transferred in a fraction of time.
Power adjustment depends first on the type of skin and on the size of the area to be treated.
In the case of chronic conditions and diseases, medium-high powers will be used (depending on the device used, from 4-5 Watt and above).
Pulsed mode is preferable in order to avoid overheating of the skin.
Opting for the “duty cycle” (i.e. the ratio between the active phase and the passive of the impulse) may favour the active phase.
In the case of acute conditions and diseases it will be necessary to act quickly meaning high powers are to be used (in the order of 2-3 W and above).
In an acute condition, if inflammation is present, it is advisable to work in pulsed mode, in order to reduce the average power delivered and not to worsen the inflammatory state.
In this case, opting for the duty cycle may favour the passive phase.
Low powers must be used on very sensitive people and on people with very dark skin, selecting a duty cycle with reduced active phase (around 20-30%).
Some considerations on laser therapy
Is it difficult to set up a laser’s operating programmes? Fortunately, professional devices have a list of pre-set programmes and conditions that allow the operator to work safely and without too many worries.
During treatment, safety glasses must ALWAYS be worn both by the operator and by the patient. In addition, the therapist must speak to the patient and make sure that they do not experience any pain due to excessive heating during therapy.