Here are ten articles from a PubMed search for “chronic pain” and either “photobiostimulation” or the more commonly used term “low level laser treatment” (LLLT). I found 2 articles from 2004 using the term “photobiostimulation”, and 8 articles from the last 5 years on LLLT that seem to indicate this treatment has a potential for pain management.
Biostimulating lasers have analgesic, anti-inflammatory, and antiallergenic effects, and relieve muscle cramps; they also improve metabolism and regenerate cells and tissue. Laser photobiostimulation is an effective, quick, aseptic therapy, with no age limitations or side effects.
Laser therapy based on the stimulating and healing action of light of low-intensity lasers (LIL), along with laser surgery and photodynamic therapy, has been lately widely applied in the irradiation of human tissues in the absence of exogenous photosensitizers. Besides LIL, light-emitting diodes are used in phototherapy (photobiostimulation) whose action, like that of LIL, depends on the radiation wavelength, dose, and distribution of light intensity in time but, according to all available data, does not depend on the coherence of radiation.
Exposure to lasers as well as LED light is currently applied in therapy. The most effective irradiation is that in the red and near infrared range of the spectrum
The main reason for using the sources radiating in the red and near infrared spectral region is the fact that hemoglobin does not absorb in this region and light can penetrate deep into living tissue.
A randomized, double-blind, placebo-controlled study of low-level laser therapy (LLLT) in 90 subjects with chronic neck pain was conducted with the aim of determining the efficacy of 300 mW, 830 nm laser in the management of chronic neck pain.
Subjects were randomized to receive a course of 14 treatments over 7 weeks with either active or sham laser to tender areas in the neck. The primary outcome measure was change in a 10 cm Visual Analogue Scale (VAS) for pain.
Secondary outcome measures included Short-Form 36 Quality-of-Life questionnaire (SF-36), Northwick Park Neck Pain Questionnaire (NPNQ), Neck Pain and Disability Scale (NPAD), the McGill Pain Questionnaire (MPQ) and Self-Assessed Improvement (SAI) in pain measured by VAS.
Measurements were taken at baseline, at the end of 7 weeks’ treatment and 12 weeks from baseline.
The mean VAS pain scores improved by 2.7 in the treated group and worsened by 0.3 in the control group (difference 3.0, 95% CI 3.8-2.1).
Significant improvements were seen in the active group compared to placebo for SF-36-Physical Score (SF36 PCS), NPNQ, NPAD, MPQVAS and SAI. The results of the SF-36 – Mental Score (SF36 MCS) and other MPQ component scores (afferent and sensory) did not differ significantly between the two groups.
Low-level laser therapy (LLLT), at the parameters used in this study, was efficacious in providing pain relief for patients with chronic neck pain over a period of 3 months.
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.
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.
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.
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.
Three types of machines are used in the field of phototherapy for chronic pain. One type is an instrument for low reactive level laser therapy (LLLT), one is an instrument for linear polarized infrared light irradiation (SUPER LIZER), and the last one is an instrument for Xenon light irradiation (beta EXCEL Xe10).
The available machines for LLLT all project laser by semiconductor. The newest machine (MEDILASER SOFT PULSE10) has peak power of 10 W and mean power of 1 W. This machine is as safe as 1 W machine and is effective twice as deep as the 1 W machine.
The irradiation by low reactive level laser induces hyperpolarization, decreased resistance of neuronal membrane, and increased intra-cellular ATP concentrations. The effects of low reactive level laser might be induced by the activation of ATP-dependent K channel. The significant analgesic effects of 1 W and 10 W LLLT were reported with double blind test. The significant analgesic effects of linear polarized near infrared light irradiation with double blind test were also reported. The effects of low reactive level laser upon the sympathetic nerve system were thought to result from its normalization of the overloaded sympathetic nerve system.
The objective of this review was to systematically identify experimental studies of non-ablative laser irradiation (LI) on peripheral nerve morphology, physiology, and function. The findings were then evaluated with special reference to the neurophysiology of pain and implications for the analgesic effects of low-level laser therapy (LLLT).
We searched computerized databases and reference lists for studies of LI effects on animal and human nerves using a priori inclusion and exclusion criteria.
We identified 44 studies suitable for inclusion. In 13 of 18 human studies, pulsed or continuous wave visible and continuous wave infrared (IR) LI slowed conduction velocity (CV) and/or reduced the amplitude of compound action potentials (CAPs). In 26 animal experiments, IR LI suppressed electrically and noxiously evoked action potentials including pro-inflammatory mediators. Disruption of microtubule arrays and fast axonal flow may underpin neural inhibition.
This review has identified a range of laser-induced inhibitory effects in diverse peripheral nerve models, which may reduce acute pain by direct inhibition of peripheral nociceptors. In chronic pain, spinal cord changes induced by LI may result in long-term depression of pain. Incomplete reporting of parameters limited aggregation of data.
Inhibitory effects of visible 650-nm and infrared 808-nm laser irradiation on somatosensory and compound muscle action potentials in rat sciatic nerve: implications for laser-induced analgesia… [J Peripher Nerv Syst. 2011] – PubMed – NCBI
Low-level laser therapy (LLLT) has been shown in clinical trials to relieve chronic pain and the World Health Organization has added LLLT to their guidelines for treatment of chronic neck pain. The mechanisms for the pain-relieving effects of LLLT are however poorly understood.
We therefore assessed the effects of laser irradiation (LI) on somatosensory-evoked potentials (SSEPs) and compound muscle action potentials (CMAPs) in a series of experiments using visible (λ = 650 nm) or infrared (λ = 808 nm) LI applied transcutaneously to points on the hind limbs of rats overlying the course of the sciatic nerve. This approximates the clinical application of LLLT.
The 650-nm LI decreased SSEP amplitudes and increased latency after 20 min. CMAP proximal amplitudes and hip/ankle (H/A) ratios decreased at 10 and 20 min with increases in proximal latencies approaching significance. The 808-nm LI decreased SSEP amplitudes and increased latencies at 10 and 20 min. CMAP proximal amplitudes and H/A ratios decreased at 10 and 20 min. Latencies were not significantly increased. All LI changes for both wavelengths returned to baseline by 48 h.
These results strengthen the hypothesis that a neural mechanism underlies the clinical effectiveness of LLLT for painful conditions.
Background and Aims:
Sacroiliac joint pain not associated with a major etiological factor is a common problem seen in the orthopedic clinical setting, but diagnosis is difficult because of the anatomical area and thus it is sometimes difficult to effect a complete cure. Low level laser therapy (LLLT) has been well-reported as having efficacy in difficult pain types, so the following preliminary study was designed to assess the efficacy of LLLT for sacroiliac pain.
Materials and Methods:
Nine patients participated, 4 males and 5 females, average age of 50.4 yrs, who attended the outpatient department with sacroiliac pain. The usual major disorders were ruled out. Pain was assessed subjectively pre-and post-LLLT on a visual analog scale, and trunk range of motion was examined with the flexion test to obtain the pre- and post-treatment finger to floor distance (FFD). The LLLT system used was an 830 nm CW diode laser, 1000 mW, 30 sec/point (20 J/cm(2)) applied on the bilateral tender points twice/week for 5 weeks. Baseline and final assessment values (after the final treatment session) were compared with the Wilcoxon signed rank test (nonparametric score).
All patients completed the study. Eight of the 9 patients showed significant pain improvement and 6 demonstrated significantly increased trunk mobility (P pain, and this may be due to improvement of the blood circulation of the strong ligaments which support the sacroiliac joint, activation of the descending inhibitory pathway, and the additional removal of irregularities of the sacroiliac joint articular surfaces. Further larger-scale studies are warranted.
Free PMC Article http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799023/
The effect of low intensity laser radiation in the treatment of acute and chronic pain is now established in many studies.
Tri-geminal neuralgia is a pain passes through nerve’s branches and its trigger is located in skin or mucosa that could lead to pain with a trigger stimulus. The pain involved branches of trigeminal nerve that sometimes has patients to seek the treatment for several years.
Nowadays different treatments are used for relief of pain that most of them cause tolerance and various side effects. This paper reviews and summarizes scientific papers available in English literature publishedin PubMed, Scopus, Science Direct, Inter science, and Iran Medex from 1986 until July 2011 about the effect of these types of lasers on trigeminal neuralgia which is one of the most painful afflictions known. In different studies, the effect of laser therapy has been compared with placebo irradiation or medicinal and surgical treatment modalities.
Low-level laser therapy (LLLT) is a treatment strategy which uses a single wavelength light source. Laser radiation and monochromatic light may alter cell and tissue function. However, in most studies laser therapy was associated with significant reduction in the intensity and frequency of pain compared with other treatment strategies, a few studies revealed that between laser and placebo group there was not any significant difference according to the analgesic effect. Low-level laser therapy could be considered in treatment of trigeminal neuralgia without any side effects.