OBJECTIVE: Laser phototherapy has been widely used to relieve pain for more than 30 years, but its efficacy remains controversial. To ascertain the overall effect of phototherapy on pain, we aggregated the literature and subjected the studies to statistical meta-analysis.
METHODS: Relevant original studies were gathered from every available source and coded. Articles that met preestablished inclusion criteria were subjected to statistical meta-analysis, using Cohen's d statistic to determine treatment effect sizes.
RESULTS: Fifty-two effect sizes were computed from the 22 articles that met the inclusion criteria. The resulting overall mean effect size was highly significant; d = +0.84 (95% confidence interval = 0.44-1.23). The effect size remained significant even when a high outlying d value was conservatively excluded from the analysis; d = +0.66 (95% confidence interval = 0.46-0.86). The fail-safe number associated with the overall treatment effect, that is, the number of additional studies in which phototherapy has negative or no effect on pain needed to negate the overall large effect size of +0.84, was 348.
DISCUSSION: These findings warrant the conclusion that laser phototherapy effectively relieves pain of various etiologies; making it a valuable addition to contemporary pain management armamentarium.
Objective: The semiconductor or laser diode (GaAs, 904 nm) is the most appropriate choice in pain reduction therapy.
Summary Background Data: Low-power density laser acts on the prostaglandin (PG) synthesis, increasing the change of PGG2 and PGH2 into PG12 (also called prostacyclin, or epoprostenol). The last is the main product of the arachidonic acid into the endothelial cells and into the smooth muscular cells of vessel walls, that have a vasodilating and anti-inflammatory action.
Methods: Treatment was performed on 372 patients (206 women and 166 men) during the period between May 1987 and January 1997. The patients, whose ages ranged from 25 to 70 years, with a mean age of 45 years, suffered from rheumatic, degenerative, and traumatic pathologies as well as cutaneous ulcers. The majority of patients had been seen by orthopedists and rheumatologists and had undergone x-ray examination. All patients had received drug-based treatment and/or physiotherapy with poor results; 5 patients had also been irradiated with He:Ne and CO2 lasers. Two-thirds were experiencing acute symptomatic pain, while the others suffered long-term pathology with recurrent crises. We used a pulsed diode laser, GaAs 904 nm wavelength once per day for 5 consecutive days, followed by a 2-day interval. The average number of applications was 12. We irradiated the trigger points, access points to the joint, and striated muscles adjacent to relevant nerve roots.
Results: We achieved very good results, especially in cases of symptomatic osteoarthritis of the cervical vertebrae, sport-related injuries, epicondylitis, and cutaneous ulcers, and with cases of osteoarthritis of the coxa.
Conclusions: Treatment with 904-nm diode laser has substantially reduced the symptoms as well as improved the quality of life of these patient, ultimately postponing the need for surgery.
OBJECTIVES: A randomized double-blind study was conducted to compare the efficacy of superpulsed low-level laser therapy (SLLLT) with nonsteroidal anti-inflammatory drugs in the treatment of pain caused by temporomandibular joint disorders.
METHODS: A total of 99 patients with temporomandibular joint disorders, secondary to disc displacement without reduction or osteoarthritis were randomly divided into 3 groups. Thirty-nine patients received SLLLT in 10 sessions over 2 weeks, 30 patients received ibuprofen 800 mg twice a day for 10 days, and 30 patients received sham laser as placebo in 10 sessions over 2 weeks. Pain intensity was measured by visual analog scale at baseline, 2, 5, 10, and 15 days of treatment. Mandibular function was evaluated by monitoring active and passive mouth openings and right and left lateral motions at baseline, 15 days, and 1 month of treatment. Magnetic resonance imaging was performed at baseline and the end of therapy.
RESULTS: Mean visual analog scale pain scores in SLLLT group was significantly lower than in nonsteroidal anti-inflammatory drug group and control group (P=0.0001) from fifth day up to the end of the observation period. As for active and passive mouth openings and right and left lateral motions, superiority of SLLLT was evident 1 month after treatment (interaction time treatment, P=0.0001).
DISCUSSION: Mandibular function improved in all SLLLT patients proving the effectiveness in the treatment of pain, as demonstrated by a significant improvement in clinical signs and symptoms of temporomandibular joint disc displacement without reduction and osteoarthritis at the end of treatment and stability over a period of 1 month.
Temporomandibular disorders (TMDs) are common painful multifactorial conditions affecting the temporomandibular joint (TMJ) and whose treatment depends on the type and symptoms. Initially, it requires pain control, and, for this, drugs, biting plates, occlusal adjustment, physiotherapy or their association are used. Lately, laser phototherapy (LPT) has been used in the treatment of pain of several origins, including TMDs. This study reports the treatment of a selected group of 74 patients treated at the Laser Center of the Federal University of Bahia between 2003 and 2008. Following standard anamneses, clinical and imaging examination and with the diagnosis of any type of TMD, the patients were prepared for LPT. No other intervention was carried out during the treatment. Treatment consisted of three sessions a week for 6 weeks. Prior to irradiation, the patients were asked to score their pain using a visual analog scale (VAS). Lasers of wavelength (lambda)780 nm, lambda790 nm or lambda830 nm and/or lambda660 nm were used at each session (30/40 mW; spot (varphi) approximately 3 mm; mean dose per session 14.2 +/- 6.8 J/cm(2); mean treatment dose of 170 +/- 79.8 J/cm(2)). Of the patients, 80% were female ( approximately 46 years old). At the end of the 12 sessions the patients were again examined, and they scored their pain using the VAS. The results were statistically analyzed and showed that 64% of the patients were asymptomatic or had improved after treatment and that the association of both wavelengths was statistically significant (P = 0.02) in the asymptomatic group. It was concluded that the association of red and infrared (IR) laser light was effective in pain reduction on TMJ disorders of several origins.
The purpose of this study was to evaluate the effect of diode laser (GaAIAs - 780 nm) on pain to palpation and electromyographic (EMG) activity of the masseter and anterior temporalis muscles. The laser was applied on the temporalis and masseter muscles twice a week (four weeks). Forty-eight (48) patients with myofascial pain were randomly assigned between actual and placebo treatments and between the energetic doses of 25 J/cm2 and 60 J/cm2, and were evaluated using VAS before, immediately after the final application, and 30 days after the laser treatment. Surface electromyography was performed with maximum dental clenching before and after laser therapy. The results show there were no significant statistical differences in the EMG activity between the groups before and after laser treatment. With regard to the pain at palpation, although both groups presented a significant difference in the symptoms before and after the treatment, only the active doses showed statistically significant reductions in pain level in all the regions of the palpated muscles. However, there was no significant statistical difference between groups (experimental and placebo). In conclusion, low level laser did not promote any changes in EMG activity. The treatment did, however, lessen the pain symptoms in the experimental groups.
BACKGROUND: Neck pain is a common and costly condition for which pharmacological management has limited evidence of efficacy and side-effects. Low-level laser therapy (LLLT) is a relatively uncommon, non-invasive treatment for neck pain, in which non-thermal laser irradiation is applied to sites of pain. We did a systematic review and meta-analysis of randomised controlled trials to assess the efficacy of LLLT in neck pain.
METHODS: We searched computerised databases comparing efficacy of LLLT using any wavelength with placebo or with active control in acute or chronic neck pain. Effect size for the primary outcome, pain intensity, was defined as a pooled estimate of mean difference in change in mm on 100 mm visual analogue scale.
FINDINGS: We identified 16 randomised controlled trials including a total of 820 patients. In acute neck pain, results of two trials showed a relative risk (RR) of 1.69 (95% CI 1.22-2.33) for pain improvement of LLLT versus placebo. Five trials of chronic neck pain reporting categorical data showed an RR for pain improvement of 4.05 (2.74-5.98) of LLLT. Patients in 11 trials reporting changes in visual analogue scale had pain intensity reduced by 19.86 mm (10.04-29.68). Seven trials provided follow-up data for 1-22 weeks after completion of treatment, with short-term pain relief persisting in the medium term with a reduction of 22.07 mm (17.42-26.72). Side-effects from LLLT were mild and not different from those of placebo.
INTERPRETATION: We show that LLLT reduces pain immediately after treatment in acute neck pain and up to 22 weeks after completion of treatment in patients with chronic neck pain.
Limited studies have demonstrated that low intensity laser therapy (LILT) may have a therapeutic effect on the treatment of myofascial pain syndrome (MPS). Sixty (60) patients with MPS and having one active trigger point in the anterior masseter and anterior temporal muscles were selected and assigned randomly to six groups (n=10): Groups I to Ill were treated with GaAIAS (780 nm) laser, applied in continuous mode and in a meticulous way, twice a week, for four weeks. Energy was set to 25 J/cm2, 60 J/cm2 and 105 J/cm2, respectively. Groups IV to VI were treated with placebo applications, simulating the same parameters as the treated groups. Pain scores were assessed just before, then immediately after the fourth application, immediately after the eighth application, at 15 days and one month following treatment. A significant pain reduction was observed over time (p < 0.001). The analgesic effect of the LILT was similar to the placebo groups. Using the parameters described in this experiment, LILT was effective in reducing pain experienced by patients with myofascial pain syndrome. Thus, it was not possible to establish a treatment protocol. Analyzing the analgesic effect of LILT suggests it as a possible treatment of MPS and may help to establish a clinical protocol for this therapeutic modality.
Clinically, Low Level Laser Therapy - LLLT has been used successfully in the treatment of chronic pain but many have questioned the scientific basis for its use. Many studies have been poorly designed or poorly controlled. A double-blind, placebo-controlled, random allocation study was designed to analyse the effect of second daily infrared (JR) laser (820 nm, 25 mW) and visible red laser (670 nm, 10 mW) at 1 J/cm2 and 5 J/cm2 on chronic pain. Forty-one consenting subjects with chronic pain conditions exhibiting myofascial trigger points in the neck and upper trunk region underwent five treatment sessions over a two week period. To assess progress, pain scores were measured using visual analogue scales before and after each treatment. The incidence of side effects was recorded. All groups demonstrated significant reductions in pain over the duration of the study with those groups which received infrared (820 nm) laser at I J/cm2 and 5 J/cm2. demonstrating the most significant effects (p < 0.001). Only those subjects who had active laser treatment experi enced side effects. Results indicated that responses to LLLT at the parameters used in this study are subject to placebo and may be dependant on power output, dose and/ or wavelength.