BIOPHYSICAL ASPECTS OF LOW LEVEL LASER THERAPY

Herbert Klima Atomic Institute of the Austrian Universities, Vienna, Austria

Biophysical aspects of low level laser therapy will be discussed from two points of view: from the electromagnetic and the thermodynamical point of view. From electromagnetic point of view, living systems are mainly governed by he electromagnetic interaction whose interacting particles are called photons. Each interaction beween molecules, macromolecules or living cells is basically electromagnetic and governed by photons. For this reason, we must expect that electromagnetic influences like laser light of proper wavelength will have remarkable impact on the regulation of living processes.
An impressive example of this regulating function of various wavelengths of light is found in the realm of botany, where photons of 660 nm are able to trigger the growth of plants which leads among other things to the formation of buds. On the other hand, irradiation of plants by 730 nm photons may stop the growth and the flowering. Human phagocyting cells are natively emitting light which can be detected by single photon counting methods. Singlet oxygen molecules are the main sources of this light emitted at 480, 570, 633, 760, 1060 and 1270 nm wavelengths. On the other hand, human cells (leukocytes, lymphocytes, stem cells, fibroblasts, etc) can be stimulated by low power laser light of just these wavelengths.

From thermodynamical point of view, living systems - in contrast to dead organisms - are open systems which need metabolism in order to maintain their highly ordered state of life. Such states can only exist far from thermodynamical equilibrium thus dissipating heat in order to maintain their high order and complexity. Such nonequilibrium systems are called dissipative structures proposed by the Nobel laureat I. Prigogine. One of the main feature of dissipative structures is their ability to react very sensibly on weak influences, e.g. they are able to amplify even very small stimuli.
Therefore, we must expect that even weak laser light of proper wavelength and proper irradiation should be able to influence the dynamics of regulation in living systems. For example, the transition from a cell at rest to a dividing one will occur during a phase transition already influenced by the tiniest fluctuations. External stimuli can induce these phase transitions which would otherwise not even take place. These phase transitions induced by light can be impressively illustrated by various chemical and physiological reactions as special kinds of dissipative systems. One of he most important biochemical reaction localized in mitochondria is the oxidation of NADH in the respiratory chain of aerobic cells. A similar reaction has been found to be a dissipative process showing oscillating and chaotic behavior capable to absorb and amplify photons of proper wavelength.

A great variety of experimental and clinical results in the field of low level laser therapy supports these two biophysical points of view concerning the interaction between life and laser light. Our former, but also our recent experimental results on the effects of low level laser light on human cells are steps in this direction. By using cytometric, photometric and radiochemical methods it is shown that the increase or decrease of cells growth depends on the applied wavelenghts (480, 570, 633, 700, 760, 904, 1060, 1270 nm), on the irradiance (100 - 5000 J/m2), on the pulse sequence modulated to laser beams (constant, periodic, chaotic pulses), on the type of cells (leukocytes, lymphocytes, fibroblasts, normal and cancer cells) and on the density of the cells in tissue cultures.

Our experimental results support our hypothesis which states that triplet oxygen molecules are able to absorb proper laser light at wavelenght at wavelenghts 480, 570, 633, 700, 760, 904, 1060, 1270 nm thus producing singlet oxygen molecules. Singlet oxygen takes part in many metabolic processes, e.g. catalytic oxydation of NADH which has been shown to be a dissipative system far from thermodynamical equilibrium and sensitive even to small stimuli. Therfore, laser light of proper wavelenght and irradiance in low level laser therapy is assumed to be able to exicte oxygen molecules thus influencing or amplifying metabolism and consequently influencing and supporting fundamental healing processes.

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IMPROVEMENT OF PAIN AND DISABILITY IN ELDERLY PATIENTS WITH DEGENERATIVE OSTEOARTHRITIS OF THE KNEE TREATED WITH NARROW-BAND LIGHT THERAPY (LLLT).

Jean Stelian, MD, Israel Gil, MD, Beni Habot, MD, Michal Rosenthal, MD, Iulian Abramovici, MD, Nathalia Kutok, MD, and Auni Khahil, MD

Objective: To evaluate the effects of low-power light therapy (LLLT) on pain and disability in elderly patients with degenerative osteoarthritis in the knee.

Design: Partially double-blinded, fully randomized trial comparing red, infrared, and placebo light emitters.

Patients: Fifty patients with degenerative osteoarthritis of both knees were randomly assigned to three treatment groups: red (15 patients), infrared (18 patients) and placebo (17 patients). Infrared and placebo emitters were double-blinded.

Interventions: Self-applied treatment to both sides of the knee for 15 minutes twice a day for 10 days.

Main Outcome Measures: Short-Form McGill Pain Questionnaire, Present Pain Intensity, and Visual Analogue Scale for pain and Disability Index Questionnaire for disability were used. We evaluated pain and disability before and on the tenth day of therapy. The period from the end of the treatment until the patient’s request to be retreated was summed up 1 year after the trial. Results: Pain and disability before treatment did not show statistically significant differences between the three groups. Pain reduction in the red and infrared groups after the treatment was more than 50% in all scoring methods (P < 0.05). There was no significant pain improvement in the placebo group. We observed significant functional improvement in red and infrared treated groups (p < 0.05), but not in the placebo group. The period from the end of treatment until the patients required retreatment was longer for red and infrared groups than for the placebo group (4.2 ± 3.0, 6.1 ± 3.2, and 0.53 ± 0.62 months, for red, infrared, and placebo respectively)

Conclusions: Low-power light therapy is effective in relieving pain and disability in degenerative osteoarthritis of the knee. Degenerative osteoarthritis (DOA) is the most common rheumatic disorder of man and causes pain and disability especially in elderly people.1 Autopsy surveys show that degenerative changes in joints begin as early as the second decade of life. 2 Roentgenographic studies conducted in the United States showed osteoarthritic changes in 4 percent of persons under 24 years of age in 85 percent at 75 to 79 years of age. Symptomatic manifestations of osteoarthritis increase with ageing, reflecting disease changes that begin in early life and progress slowly over a period of many decades. 3-4

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INFARED DIODE LASER IN LOW REACTIVE-LEVEL LASER THERAPY (LLLT) FOR KNEE OSTEOARTHROSIS

M. A. Trelles, J. Rigau, P. Sala, G. Calderhead and T. Ohshiro

Degenerative joint disease (DJD) in particular in the knee. is difficult to, cure successfully at present often requiring surgical intervention. In addition the chronic DJD patient often exhibits symptoms cl both a physiological and psychological nature. A study is presented using high reactive-level laser therapy (LLLT) with an 830 nm infra red continuous wave gallium aluminium (or aluminium) arsenide (GaAlAs) diode laser with an output power of 60 mW. in light contact Laser therapy for a population of 40 patients (power density of approximately 3 W/cm2). Four points around the patella were irradiated for 60 s each (energy density of 18 J/cm2 per point. total of 72 J/cm2 per session) two sessions per week for eight weeks. Radiological, pain score and joint mobility assessments were made before the first session, immediately after at 4 months after the final LLT session. All other medication and physical therapy was discontinued at least 15 days prior to the first treatment session. Thirty-three patients (82%) reported significant removal of pain and recovery of articular joint mobility. The remaining seven patients felt there was no significant effect following LLLT and returned to their original pretherapy medication. The side effects were minimal LLLT is concluded to to be safe, effective and non-invasive alternative to conventional surgical and medical treatment modalities for DJD patients.