Efficacy of 635nm Red Low-Level Laser on Nociceptive Musculoskeletal Pain Compared to NSAIDS, Opioids, and Other Light Sources
Background: According to the World Health Organization, musculoskeletal conditions comprise more than 150 diagnoses affecting muscles, bones, joints and related tissues including tendons and ligaments. The use of 635nm red low-level laser has demonstrated beneficial effects for treating a range of painful musculoskeletal conditions including low back pain, plantar fasciitis, neck, and shoulder pain.
Methods: Data is compiled from six IRB-approved clinical trials which assessed the efficacy of 635 nm lasers for reducing pain arising from chronic conditions. These included five randomized, placebo-controlled studies and one randomized comparative study.
Results: Among subjects in the active treatment group, there was a 45.4% mean decrease in VAS scores compared to a 15.1% mean decrease among sham-treated subjects (p<0.0001). The active treatment group also documented significant improvement in range of motion, oswestry disability index, and foot function index.
Conclusion: Based on the data the Food and Drug Administration (FDA) cleared the first low-level laser for the indication as adjunctive use in providing temporary relief of nociceptive musculoskeletal pain.
According to the World Health Organization, musculoskeletal conditions comprise more than 150 diagnoses affecting muscles, bones, joints and related tissues including tendons and ligaments. 1 The most common and disabling conditions are osteoarthritis, back and neck pain, fractures associated with bone fragility, injuries, and systemic inflammatory conditions such as rheumatoid arthritis . It has been estimated that 107.5 million people experience musculoskeletal disease annually in the United States . As the prevalence of musculoskeletal conditions is substantially higher among the elderly, the overall prevalence is likely to increase due to this growing population. The aggregate costs among persons with musculoskeletal diseases including direct healthcare costs and lost wages was estimated to be $980 billion annually during 2012-2014 . According to the Medical Expenditure Panel Survey, the annual cost of pain management was greater than the annual costs of heart disease, cancer, and diabetes . Low back pain is one of the most prevalent musculoskeletal conditions requiring treatment and among the most common conditions presenting to primary care physicians . According to one systematic review, the 1-year prevalence of low back pain ranged from 22 to 65%, and lifetime prevalence ranged from 11 to 84% .
Traditional pharmacotherapy for managing low back pain has consisted of nonsteroidal anti-inflammatory drugs (NSAIDs) which inhibit cyclo-oxygenase (Cox), thereby preventing the formation of inflammatory prostaglandins . Overall, NSAIDs are superior to placebo for treating chronic low back pain with no significant difference in pain reduction between Cox-2 selective and traditional NSAID . Unfortunately, their use can be limited by gastrointestinal and cardiac toxicity [7,8], although newer Cox-2 selective inhibitors (celecoxib, rofecoxib) are safer than traditional NSAIDs (naproxen, ibuprofen) . A promising alternative to pharmacotherapy is the use of low-level laser therapy (LLLT). In June 2019, The Food and Drug Administration (FDA) cleared the first low-level laser (Erchonia® FX-635™) for the indication as adjunctive use in providing temporary relief of nociceptive musculoskeletal pain (K190572). The 510(k) clearance was based on numerous completed studies that demonstrated effectiveness for treating various anatomical areas affected by chronic musculoskeletal pain. The objective of the following review is to analyze data from six studies totaling 419 subjects assessing immediate efficacy, long-term durability, and functional index improvement using red 635 nm (Erchonia Corp.) nonthermal laser devices for the treatment of chronic musculoskeletal conditions.
Data is compiled from six IRB-approved clinical trials which assessed the efficacy of 635 nm lasers for reducing pain arising from chronic painful conditions. These included five randomized, placebo-controlled studies and one randomized comparative study [9-12]. Several of these studies have been previously published [13-16]. The devices utilized 635 nm red laser diodes ranging from 5 – 17.5mw(Erchonia Corporation, Melbourne, FL). The variable hertz feature of each device is a pulsed wave, defined as containing a preprogrammed series of breaks. The devices internal mechanics collect light emitted from each laser diode which is processed through a proprietary patented lens to produce a line generated beam. The total energy delivered was between 4 – 10.5 joules to the treatment area . The sham devices applied light-emitting diodes (LED) light of the same color when activated.
The assessed treatment areas included chronic neck and shoulder pain, low back pain and heel pain caused by plantar fasciitis. Each condition has previously received a respective FDA indication based on submitted clinical data (K012580, K132940, K180197). Adult male and female subjects were enrolled in each study. The total study sample (N=419) included subjects that received active treatment (n=234) and sham treatment (n=185) as indicated in Table 1.
For each clinical trial, pain severity was assessed by subjects using a 0-100 Visual Analog Scale (VAS). The VAS is widely used across a broad range of populations and clinical settings and has been well-accepted as a generic pain measure for many years . The following analysis is based on the change in mean pretreatment subject VAS scores at study endpoint. The relevance of endpoint evaluation was consistent across all trials. The individual subject treatment success criterion in each trial was preestablished, as stipulated by the Food and Drug Administration, as a ≥35% decreased VAS pain scores between treatment and sham group.
Five trials recorded post-treatment VAS pain scores from 24 hours to 12 months. As the timing of post-treatment pain evaluations was inconsistent, longitudinal VAS pain scores are reported for two time periods that enabled combining data from two or more studies for evaluation. These time points were 2 to 4 weeks and 2 to 4 months post-treatment. Subject satisfaction with pain relief was evaluated by subjects using a 5-point Likert scale (Table 2).
A t-test for two independent samples was used to evaluate the difference in mean changes in baseline VAS pain scores for subjects in the active and sham treatment groups. A Fischer’s Exact Test for two independent proportions was used to compare the difference in individual treatment successes between treatment groups. Change in Oswestry Disability Index (ODI) % total score index scores were evaluated using analysis of covariance, with change from baseline to endpoint in ODI % total index score as the dependent variable, baseline ODI % total score index as the covariate and treatment group as a main effect. A one-way analysis of variance for four correlated samples was used to assess changes in mean total Foot Function Index (FFI) scores, and a subsequent Tukey HSD test was used to assess changes in mean Total FFI scores between various assessment points.
Among subjects in the active treatment group, there was a 45.4% mean decrease in VAS scores compared to a 15.1% mean decrease among sham-treated subjects (p<0.0001). These results are summarized in Figure 1. The 27.5-point mean decrease in VAS scores among subjects treated with active treatment devices was >3-fold greater than the 8. 7-point mean decrease in VAS scores among sham-treated subjects.