REPORT ON A COMPUTER-RANDOMIZED DOUBLE BLIND CLINICAL TRIAL TO DETERMINE THE EFFECTIVENESS OF THE GaAlAs (830 NM) DIODE LASER FOR PAIN ATTENUATION IN SELECTED PAIN GROUPS

Abstract

The efficiency of infrared (IR) diode low reactive-level laser therapy (LLLT) has been reported in a variety of pain complaints. In order to ascertain if LLLT is particularly effective in a given pain group, 115 informed and consenting patients in two institutions (Toho University and Keio University, Tokyo, same ambient environmental parameters in treatment rooms) were assigned to groups according to the aetiology of their pain condition. Each patient's name was placed against a number, and a randomization computer program selected either real or sham (placebo) irradiation for each number, and thus each patient. The computer directly controlled the laser system appropriately, and stored the information on disc for retrieval after the trial was finished. The computer was located remotely from the treatment room. Neither the patient nor the therapist knew if they were in the real or placebo group: in placebo therapy, only laser emission was absent, the visible and audible emission indicators behaving exactly as in “real” treatment. The laser used was a gallium aluminium arsenide (GaAlAs) diode laser, 60 mW output, 830 nm, continuous wave. The laser was applied in the contact technique, with an incident power density of ≅ 3 W/cm2, total exposure time per session of from 5-10 min (energy density ≅ 900 ∼ 1800 J/cm2). There were three groups: the extremity joint pain (35), cervical pain (39) and lumbar pain (41) groups. This gave a total of 115 patients (53 female, 62 male, ages from 18∼82, mean age 49.2 ± 15.3). 82% of those who received real treatment in the total population reported effective pain relief, compared with 42% of those who were assigned to receive sham treatment. Following the trial, the data were analyzed statistically applying the χ2 and Fisher’s tests, giving a value of χ2 = 21.328 (df=1), with a value for p = ‹ 0.0001 at a level of confidence of less than 1%, a statistically significant difference for the real versus the placebo treatment. There were no statistically significant differences in the results between the individual pain groups in the two sites. No adverse side effects were reported. It was concluded that diode laser therapy, at the parameters used in the trial, was both safe and effective for alleviation of pain in the groups treated.