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Cold Laser Therapy Clinical Studies

Laser-Accelerated Inflamation/Pain Reduction and Healing

Richard Martin, BS, CLT

Injured cells and tissues have greater affinity for LLLT than healthy cells and tissues. Effect of laser amplifies more easily in damaged cells and tissue because the particular emitted enzymes encourage receipt of LLLT treatment.

LLLT in the treatment of inflammation, pain and healing is a highly integrated process, but the author separates those processes categorically for identification.

Acute Inflammation Reduction (flowchart provided in the original article) – After the injury, tissues initiate a series of biological responses and cellular membrane reactions which manifest in a combination of edema, inflammation, pain and functional debility. LLLT mediates the situation by: (1) Stabilization of cellular membrane; (2) Enhancement of molecule ATP production and synthesis; (3) Stimulated vasodilation via increased Histamine, Nitric Oxide and Serotonin; (4) Beneficial acceleration of leukocytic activity; (5) Increased Prostaglandin synthesis; (6) Reduction in Interleukin-1; (7) Enhanced lymphocyte response; (8) Increased angiogenesis; (9) Temperature modulation; (10) Enhanced superoxide dismutase levels; and (11) Decreased C-reactive protein and neopterin levels.

Pain Reduction (flowchart provided in the original article) – A body of medical evidence justifies a conclusion that LLLT reduces pain by combination of processes: (1) Increase in b-Endorphins; (2) Blocked depolarization of C-fiber afferent nerves; (3) Increased nitric oxide production; (4) Increased nerve cell action potential; (5) Axonal sprouting and nerve cell regeneration; (6) Decreased Bradykinin levels; (7) Increased release of acetylcholine; and (8) Ion channel normalization.

Tissue Healing – LLLT enhances wound healing through a series of processes: (1) Enhanced leukocyte infiltration; (2) Increased macrophage activity; (3) Increased neovascularization; (4) Increased fibroblast proliferation; (5) Keratinocyte proliferation; (6) Early epithelialization; (7) Growth factor increases; (8) Enhanced cell proliferation and differentiation, and (9) Greater healed wound tensile strength


Clinical Efficacy of Low-power Laser Therapy on Pain and Function in Cervical Osteoarthritis.

Oezdemir F, Birtane M, Kokino S

Clinical Rheumatology (2001) 20(3): 181-184

Pain is a major symptom in cervical osteoarthritis (COA). Low-power laser (LPL) therapy has been claimed to reduce pain in musculoskeletal pathologies, but there have been concerns about this point. The aim of this study was to evaluate the analgesic efficacy of LPL therapy and related functional changes in COA. Sixty patients between 20 and 65 years of age were clinically and radiologically diagnosed COA were included in the study. They were randomized into two equal groups according to the therapies applied, either with LPL or placebo laser. Patients in each group were investigated blindly in terms of pain and pain-related physical finds, such as increased paravertebral muscle spasm, loss of lordosis and range of neck motion restriction before and after therapy. Functional improvements were also evaluated. Pain, paravertebral muscle spasm, lordosis angle, the range of neck motion and function were observed to improve significantly in the LPL group, but no improvement was found in the placebo group. LPL seems to be successful in relieving pain and improving function in osteoarthritic diseases.


Treatment of Medial and Lateral Epicondylitis – Tennis and Golfer’s Elbow – with LLLT: a multicenter double blind, placebo-controlled clinical study on 324 patients.

Simunovic Z, Trobonjaca T, Trobonjaca Z

Journal of Clinical Laser Medicine and Surgery (Jun 1998) 16(3):145-151.

Among the other treatment modalities of medial and lateral epicondylitis, LLLT has been promoted as a highly successful method. The aim of this clinical study was to assess the efficacy of LLLT using trigger points (TPs) and scanner application techniques under placebo-controlled conditions. The current clinical study was completed at two Laser Centers (Locarno, Switzerland and Opatija, Croatia) as a double-blind, placebo controlled, crossover clinical study. The patient population (n=324), with either medical epicondylitis (Golfer’s elbow; n=50) or lateral epicondylitis (Tennis elbow; n=274), was recruited. Unilateral cases of either type of epicondylitis (n=283) were randomly allocated to one of three treatment groups according to the LLLT technique applied: (1) Trigger points; (2) Scanner; (3) Combination Treatment (i.e., TPs and scanner technique). Bilateral cases of either type of epicondylitis (n=41) were subject to crossover, placebo-controlled conditions. Laser devices used to perform these treatments were infrared (IR) diode laser (GaAIAs) 830 nm continuous wave for treatment of TPs and He-Ne 632.8 nm combined with IR diode laser 904 nm, pulsed wave for scanner technique. Energy doses were equally controlled and measured in Joules/cm2 either during TPs or scanner technique sessions in all groups of patients. The treatment outcome (pain relief and functional ability) was observed and measured according to the following methods: (1) short form of McGill’s Pain Questionnaire (SF-MPQ); (2) visual analogue scales (VAS); (3) verbal rating scales (VRS); (4) patient’s pain diary; and (5) hand dynamometer. Total relief of the pain with consequently improved functional ability was achieve in 82% of acute and 66% of chronic cases, all of which were treated by combination of TPs and scanner technique. The best results were obtained using combination treatment (i.e., TPs and scanner technique). Good results are obtained from adequate treatment technique correctly applied, individual energy doses, adequate medical education, clinical experience, and correct approach of laser therapist. Under-and over irradiation dosage can result in the absence of positive therapy effects or even opposite, negative (e.g., inhibitory) effects. The data gave further evidence of the efficacy of LLLT in the management of lateral and medial epicondylitis.


Treatment of Repetitive Use Carpal Tunnel Syndrome

Smith CF, Vangsness CT, Anderson T & Good W (1995)

Proceedings SPIE (1995) 2395; 658-661.

In 1990, a randomized, double-blind study was initiated to evaluate the use of an eight-point conservative treatment program in carpal tunnel syndrome. A total of 160 patients were delineated with symptoms of carpal tunnel syndrome. These patients were then divided into two groups. Both groups were subjected to an ergonomically correct eight-point work modification program. A counterfeit LLLT unit was used in Group A, while an actual LLLT unit was used in Group B. Groups A and B were statistically significantly different in terms of return to work, conduction study improvement, and certain range of motion and strength studies.