Systematic review of the literature of low-level laser therapy (LLLT) in the management of neck pain

Multimodal non-invasive non-pharmacological therapies for chronic pain: mechanisms and progress

BACKGROUND

Chronic pain conditions impose significant burdens worldwide. Pharmacological treatments like opioids have limitations. Non-invasive non-pharmacological therapies (NINPT) encompass diverse interventions including physical, psychological, complementary and alternative approaches, and other innovative techniques that provide analgesic options for chronic pain without medications.

MAIN BODY

This review elucidates the mechanisms of major NINPT modalities and synthesizes evidence for their clinical potential across chronic pain populations. NINPT leverages peripheral, spinal, and supraspinal mechanisms to restore normal pain processing and limit central sensitization. However, heterogeneity in treatment protocols and individual responses warrants optimization through precision medicine approaches.

CONCLUSION

Future adoption of NINPT requires addressing limitations in standardization and accessibility as well as synergistic combination with emerging therapies. Overall, this review highlights the promise of NINPT as a valuable complementary option ready for integration into contemporary pain medicine paradigms to improve patient care and outcomes.

Feasibility study of a LED light irradiation device for the treatment of chronic neck with shoulder muscle pain/stiffness

Neck with shoulder muscle stiffness/pain is a common disorder. Commonly used physical therapy, pharmacotherapy, acupuncture, and moxibustion only temporarily alleviate the disorder in most cases, thus the disorder often recurs. Low power laser therapy is often used for neck and shoulder stiffness/pain and has been effective in clinical trials. In this study, we evaluated the safety and effectiveness of a newly developed self-care device for disorders including neck with shoulder muscle stiffness/pain. The device incorporates light-emitting diodes (LEDs), which are safer than lasers, as its light source. Ten adults with neck with shoulder muscle stiffness/pain were subject to LED irradiation (wavelength 780 nm ± 15 nm, output 750 mW, power density 3.8 W/cm2, energy density 5.7×102 J/cm2) for 3 minutes on the affected shoulder at a standard acupuncture point (GB21, Jianjing). Immediately after irradiation, the subjective symptoms of the neck with shoulder muscle stiffness and pain evaluated by a visual analog scale were improved from 58.3 mm ± 18.7 mm to 45.5 mm ± 21.5 mm and from 45.8 mm ± 23.3 mm to 39.4 mm ± 21.8 mm, respectively. The symptoms further improved after 15 minutes of irradiation. The skin temperature at the irradiated point increased from 34.3°C ± 1.1°C to 41.0°C ± 0.7°C. The increase in skin temperature was observed within approximately 5 cm of the irradiated area. There was no effect on the heart rate variability, a measure of the autonomic nervous system; however, the baroreflex sensitivity was slightly increased. No irradiation-related adverse skin events were observed. Our LED irradiation device was found to be safe, and it improved the subjective symptoms of muscle stiff neck with shoulders.

Anti-hyperalgesic effects of photobiomodulation therapy (904 nm) on streptozotocin-induced diabetic neuropathy imply MAPK pathway and calcium dynamics modulation

Several recent studies have established the efficacy of photobiomodulation therapy (PBMT) in painful clinical conditions. Diabetic neuropathy (DN) can be related to activating mitogen-activated protein kinases (MAPK), such as p38, in the peripheral nerve. MAPK pathway is activated in response to extracellular stimuli, including interleukins TNF-α and IL-1β. We verified the pain relief potential of PBMT in streptozotocin (STZ)-induced diabetic neuropathic rats and its influence on the MAPK pathway regulation and calcium (Ca²⁺) dynamics. We then observed that PBMT applied to the L4-L5 dorsal root ganglion (DRG) region reduced the intensity of hyperalgesia, decreased TNF-α and IL-1β levels, and p38-MAPK mRNA expression in DRG of diabetic neuropathic rats. DN induced the activation of phosphorylated p38 (p-38) MAPK co-localized with TRPV1⁺ neurons; PBMT partially prevented p-38 activation. DN was related to an increase of p38-MAPK expression due to proinflammatory interleukins, and the PBMT (904 nm) treatment counteracted this condition. Also, the sensitization of DRG neurons by the hyperglycemic condition demonstrated during the Ca²⁺ dynamics was reduced by PBMT, contributing to its anti-hyperalgesic effects.

Association of photobiomodulation therapy and therapeutic exercises in relation to pain intensity and neck disability in individuals with chronic neck pain: a systematic review of randomized trials

Exercise is often pointed out as an effective form of treatment in the clinical management of chronic neck pain (CNP). However, due to its complex range of causal factors and great diversity of signs and symptoms, other resources such as photobiomodulation therapy (PBMT) have been routinely used for the treatment of CNP. The aim of this study was to systematically review the literature on the use of the association of PBMT and therapeutic exercises in relation to pain intensity and neck disability in individuals with CNP. PubMed, Medline (via Ovid), Embase (via Ovid), Cinahl (via Ebsco), and Central (via Cochrane library) databases were searched using the following terms: "laser," "low-level laser," "photobiomodulation," "light emitting diodes," "phototherapy," "exercise," "chronic neck pain." After verification and implementation of eligibility criteria, seven manuscripts were considered eligible for data analysis. These manuscripts had methodological quality between 5 and 8 points on the PEDro scale. Most studies used low infrared laser therapy to perform PBMT, with a wide range of parameters and energy density between 2 and 7 J/cm² and a total treatment time between 2 and 6 weeks. Four studies showed significant benefits in terms of pain intensity at short-term follow-up and one at intermediate-term follow-up. However, only one showed a minimal clinically important change. No studies have shown significant improvement in disability. This review demonstrates that the association of PBMT with therapeutic exercises in general promotes significant benefits only for the intensity of pain. However, it does not seem to promote a minimally effective clinical difference in individuals with CNP.

Comparison of low level laser therapy and extracorporeal shock wave in treatment of chronic lateral epicondylitis

OBJECTIVE

The aim of this study was to compare the efficacy of extracorporeal shock wave therapy (ESWT) ver-sus low-level laser therapy (LLLT) in treating chronic lateral epicondylitis (CLE).

METHODS

In this prospective study, 52 patients (24 males, 28 females; mean age=48 years; age range=30-70 years) with a diagnosis of CLE were included and randomized into two groups (26 in each group): ESWT group (14 males, 12 females; mean age=48±10 years) or LLLT group (10 males, 16 females; mean age=48±11 years). ESWT was applied for 5 weeks with one session per week, while LLLT was applied with 15 sessions on consecutive days. All patients were evaluated using Disability of the Arm, Shoulder and Hand Questionnaire (DASH), Patient-Related Lateral Epicondy-litis Evaluation (PRTEE), and the 36-Item Short-Form Health Survey (SF-36) before and after the treatments.

RESULTS

In the comparison of baseline data between treatment groups, significant differences were observed only in SF-Physical functioning and SF-Energy/fatigue scores (p=0.035 and p=0.038, re-spectively), which were 77.1±17.2 and 56.3±17.2 in ESWT group and 66.5±18.0 and 44.8±21.5 in LLLT group, respectively. In the comparison of post-treatment data between groups, there were sig-nificant differences in all scores (p<0.05) except two subscales of SF-36, which were SF-role limita-tions due to emotional problems (p=0.092) and physical health (p=0.147), respectively. The other subscales of SF-36, PRTEE and DASH scores obtained after the treatments were better in ESWT group than in LLLT group. The comparison of pre-and post-treatment scores in each group revealed significant improvements in all scores (p<0.05), except SF-36 subscales, including energy/fatigue, emotional well-being, social functioning, and general health scores (p>0.05).

CONCLUSION

Evidence from this study revealed that although both treatment modalities were effective in the treatment of CLE, ESWT seemed to more effective in pain relief and functional recovery than LLLT.

LEVEL OF EVIDENCE

Level II, Therapeutic study.

Comparison of the effects between lasers applied to myofascial trigger points and to classical acupoints for patients with cervical myofascial pain syndrome

Background

To compare the immediate effectiveness of low-level laser therapy (LLLT) applied to classical acupoints versus trigger points for patients with cervical myofascial pain syndrome (MPS).

Methods

This was a single-blinded, randomized, placebo-controlled trial. This study was performed in a university-affiliated medical center. One hundred participants with cervical myofascial pain syndrome were randomly allocated to four treatment groups, including (1) acupoint therapy (AcuT), (2) acupoint control (AcuC), (3) trigger point therapy (TriT), and (4) trigger point control (TriC) groups. Low-level laser (810-nm) therapy was used in both therapy groups, while the same procedure was performed without laser in the acupoint control groups. The patients were evaluated based on visual analogue scale (VAS) pain score, pressure pain threshold, and cervical range of motion (ROM) before and after the therapy.

Results

Immediate pain relief was observed in the TriT group (p < 0.01). The TriT group showed improved cervical ROM in ipsilateral bending (p < 0.01), while the AcuT group did not.

Conclusions

LLLT applied to trigger points could significantly relieve myofascial pain and was effective in relieving cervical ROM limitations. Considering the risk of pneumothorax, laser therapy at trigger points for patients with cervical MPS may be a choice when acupuncture therapy is unavailable.

Trial registration

ClinicalTrials.gov ID: NCT01516502.

Low-Level Laser Light Therapy Dosage Variables vs Treatment Efficacy of Neuromusculoskeletal Conditions: A Scoping Review

OBJECTIVE

The purpose of this scoping review was to identify and synthesize literature on dosage variables on the efficacy of low-level laser therapy (LLLT) for neuromusculoskeletal conditions.

METHODS

A scoping literature review was conducted by searching the following databases: the Cochrane Library, the Cumulative Index to Nursing and Allied Health Literature, Medline, the Physiotherapy Evidence Database, the Index to Chiropractic Literature, manufacturer websites, and online guidelines. The search was modeled after STARLITE criteria. The reporting used Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews (PRISMA-ScR). Articles were included if LLLT was used in any treatment group for a neuromusculoskeletal complaint with dosage and effectiveness reported. This was tabulated by source, dosage variables, conditions, outcome measures, and conclusions. Data were charted in Excel format. Frequency counts were performed on ordinal data. Descriptive statistics were computed for the continuous data.

RESULTS

A total of 86 articles were included in the review. They revealed a broad range of musculoskeletal conditions and diverse dosage parameters. Seven individual parameters were found that would alter the dosage. Although duration of application is an independent clinical factor, the negative-outcome studies were inconsistent in duration. There was lack of statistical difference between the studies with improved vs unimproved outcomes. No statistical differences were noted between the dosage parameters and efficacy.

CONCLUSION

Although many articles were found on LLLT for neuromusculoskeletal conditions, the studies had amorphous parameters. A heterogeneity of reported doses precluded the synthesis of sufficient evidence to correlate dosage variables with improved or unimproved outcomes. Therefore, based on the current literature, dosage variables for the efficacy of LLLT for neuromusculoskeletal conditions are uncertain at this time.

The Mechanistic Basis for Photobiomodulation Therapy of Neuropathic Pain by Near Infrared Laser Light

Background and Objective Various irradiances have been reported to be beneficial for the treatment of neuropathic pain with near infrared light. However, the mechanistic basis for the beneficial outcomes may vary based on the level of irradiance or fluence rate used. Using in vivo and in vitro experimental models, this study determined the mechanistic basis of photobiomodulation therapy (PBMT) for the treatment of neuropathic pain using a high irradiance.

Study Design/Materials and Methods ln vitro experiments: Cultured, rat DRG were randomly assigned to control or laser treatment (L T) groups with different irradiation times (2, 5, 30, 60 or 120s). The laser parameters were: output power = 960 mW, irradiance = 300mW/cm2, 808 nm wavelength and spot size = 3cm diameter/ area = 7.07cm2, with different fluences according to irradiation times. Mitochondrial metabolic activity was measured with the MTS assay. The DRG neurons were immunostained using a primary antibody to β-Tubulin III. ln vivo experiments: spared nerve injury surgery (SNI), an animal model of persistent peripheral neuropathic pain, was used. The injured rats were randomly divided into three groups (n = 5). 1) Control: SNI without LT, 2) Short term: SNI with LT on day 7 and euthanized on day 7, 3) Long term: SNI with LT on day 7 and euthanized on day 22. An 808 nm wavelength laser was used for all treatment groups. Treatment was performed once on Day 7 post-surgery. The transcutaneous treatment parameters were: output power: 10 W, fluence rate: 270 mW/cm2, treatment time: 120s. The laser probe was moved along the course of the sciatic/sural nerve during the treatment. Within 1 hour of irradiation, behavior tests were performed to assess its immediate effect on sensory allodynia and hyperalgesia caused by SNI.

Results ln vitro experiments: Mitochondrial metabolism was significantly lower compared with controls for all LT groups. Varicosities and undulations formed in neurites of DRG neurons with a cell body diameter 30µm or less. ln neurites of DRG neurons with a cell body diameter of greater than 30µm, varicosities formed only in the 120s group. ln vivo experiments: For heat hyperalgesia, there was a statistically significant reduction in sensitivity to the heat stimulus compared with the measurements done on day 7 prior to LT. A decrease in the sensitivity to the heat stimulus was found in the LT groups compared with the control group on day 15 and 21. For cold allodynia and mechanical hyperalgesia, a significant decrease in sensitivity to cold and pin prick was found within 1 hour after L T. Sensitivity to these stimuli returned to the control levels after 5 days post-L T. No significant difference was found in mechanical allodynia between control and L T groups for all time points examined.

Conclusion These in vitro and in vivo studies indicate that treatment with an irradiance/fluence rate at 270 m W/cm2 or higher at the level of the nerve can rapidly block pain transmission. A combination therapy is proposed to treat neuropathic pain with initial high irradiance/fluence rates for fast pain relief, followed by low irradiance/fluence rates for prolonged pain relief by altering chronic inflammation.

Comparison of effects of low-level laser therapy and extracorporeal shock wave therapy in plantar fasciitis treatment: A randomized, prospective, single-blind clinical study

Objectives

The aim of this study is to compare the efficacy of extracorporeal shock wave therapy (ESWT) and low-level laser therapy (LLLT) in terms of fascia thickness, heel pain, and foot functions in patients with plantar fasciitis (PF).

Patients and methods

Between April 2015 and October 2015, a total of 34 patients (5 males, 29 females; mean age 51.5±10.8 years; range, 18 to 65 years) with PF were randomized into two treatment groups to receive either ESWT or LLLT using closed envelope method. The patients were evaluated before and after treatment and one month after treatment using the visual analog scale (VAS)-pain, Foot Function Index (FFI), and plantar fascia thickness measured by ultrasonography.

Results

A significant improvement in the VAS-pain and FFI scores and plantar fascia thickness was observed in both groups after treatment and one month after treatment, compared to pre-treatment values (p<0.05). Changes over time in these outcome parameters were not different between study groups (p>0.05).

Conclusion

Our study results suggest that both ESWT and LLLT seem to be effective on pain, foot functions, and fascia thickness in the treatment of PF.Presented at the 26th National Congress of Physical Medicine and Rehabilitation, April 25-29, 2017 Antalya, Turkey.

Clinical effectiveness of multi-wavelength photobiomodulation therapy as an adjunct to extracorporeal shock wave therapy in the management of plantar fasciitis: a randomized controlled trial

The goal of our study was to investigate the cumulative effect of combining medium-energy extracorporeal shock wave therapy (ESWT) and photobiomodulation therapy (PBMT), as well as to compare between their relative effectiveness in the management of plantar fasciitis (PF). One hundred twenty participants with chronic PF, more than 6 months with failure to respond to conservative treatment, were randomly assigned into four equal groups. Participants received either ESWT with PBMT, ESWT (once a week), PBMT (three times a week), or sham-PBMT (three times a week) for three consecutive weeks. A home exercise program was also included for all four groups. Outcome measures included pressure pain threshold (PPT), visual analogue scale (VAS), and functional foot index disability subscale (FFI-d) that were collected prior to the first treatment session and at the end of the 3-week treatment period, as well as at a follow-up session, 12 weeks after the final treatment session. There were statistically significant improvements in post-intervention and follow-up PPT, VAS, and FFI-d values in all treatment groups (P < 0.0001). As for the sham-PBMT, no significant difference was found between the pre-, post-intervention and follow-up values (P > 0.05). Bonferroni correction test revealed that there was a significant difference between all the four groups in PPT, VAS, and FFI-d values (P < 0.0001). All active treatment groups maintained the treatment effect at the 12-week follow-up. Both ESWT and PBMT were effective in increasing PPT values, decreasing pain and increasing functional ability. Additionally, application of PBMT after ESWT was shown to be superior over ESWT and PBMT alone, and ESWT was superior over PBMT in terms of reducing pain sensitivity and increasing function.Level of Evidence II.

Characterization of Macrophage/Microglial Activation and Effect of Photobiomodulation in the Spared Nerve Injury Model of Neuropathic Pain

Objective

Neuropathic pain is common and debilitating with limited effective treatments. Macrophage/microglial activation along ascending somatosensory pathways following peripheral nerve injury facilitates neuropathic pain. However, polarization of macrophages/microglia in neuropathic pain is not well understood. Photobiomodulation treatment has been used to decrease neuropathic pain, has anti-inflammatory effects in spinal injury and wound healing models, and modulates microglial polarization in vitro. Our aim was to characterize macrophage/microglia response after peripheral nerve injury and modulate the response with photobiomodulation.

Methods

Adult male Sprague-Dawley rats were randomly assigned to sham (N = 13), spared nerve injury (N = 13), or injury + photobiomodulation treatment groups (N = 7). Mechanical hypersensitivity was assessed with electronic von Frey. Photobiomodulation (980 nm) was applied to affected hind paw (output power 1 W, 20 s, 41cm above skin, power density 43.25 mW/cm 2 , dose 20 J), dorsal root ganglia (output power 4.5W, 19s, in skin contact, power density 43.25 mW/cm 2 , dose 85.5 J), and spinal cord regions (output power 1.5 W, 19s, in skin contact, power density 43.25 mW/cm 2 , dose 28.5 J) every other day from day 7-30 post-operatively. Immunohistochemistry characterized macrophage/microglial activation.

Results

Injured groups demonstrated mechanical hypersensitivity 1-30 days post-operatively. Photobiomodulation-treated animals began to recover after two treatments; at day 26, mechanical sensitivity reached baseline. Peripheral nerve injury caused region-specific macrophages/microglia activation along spinothalamic and dorsal-column medial lemniscus pathways. A pro-inflammatory microglial marker was expressed in the spinal cord of injured rats compared to photobiomodulation-treated and sham group. Photobiomodulation-treated dorsal root ganglion macrophages expressed anti-inflammatory markers.

Conclusion

Photobiomodulation effectively reduced mechanical hypersensitivity, potentially through modulating macrophage/microglial activation to an anti-inflammatory phenotype.

Effects of pulsing of light on the dentinogenesis of dental pulp stem cells in vitro

Low power light (LPL) treatment has been widely used in various clinical trials, which has been known to reduce pain and inflammation and to promote wound healing. LPL was also shown to enhance differentiation of stem cells into specific lineages. However, most studies have used high power light in mW order, and there was lack of studies about the effects of very low power light in μW. In this study, we applied 810 nm LPL of 128 μW/cm² energy density in vitro. Upon this value, continuous wave (CW) irradiation did not induce any significant changes for differentiation of human dental pulp stem cells (hDPSCs). However, the membrane hyperpolarization, alkaline phosphatase activity, and intracellular oxidative stress were largely enhanced in the pulsed wave (PW) with 30% of duty cycle and 300–3000 Hz frequencies-LPL in which LED driver work in the form of square wave. After 21 days of daily LPL treatment, Western blot revealed the dentinogenesis in this condition in vitro. This study demonstrates that the very low power light at 810 nm enhanced significant differentiation of hDPSCs in the PW mode and there were duty cycle dependency as well as pulsing frequency dependency in the efficiency.

Muscle fiber conduction velocity and EMG amplitude of the upper trapezius muscle in healthy subjects after low-level laser irradiation: a randomized, double-blind, placebo-controlled, crossover study

Although low-level laser therapy (LLLT) is an important resource for the treatment of non-specific neck pain patients, the dose which presents the greatest therapeutic potential for the treatment of this pathology is still unclear. The present study aimed to evaluate the immediate effect of LLLT on the muscle fiber conduction velocity (MFCV) and electromyographic activity (EMG) of the upper trapezius (UT) muscle in healthy individuals. A total of 20 healthy subjects were enrolled in a randomized, double-blind, crossover study. Active LLLT (820 nm wavelength, 30 mW, energy total 18 J) or placebo LLLT (pLLLT) was delivered on the UT muscle. Each subject was subjected to a single session of active LLLT and pLLLT. Surface electromyography (sEMG) signal of the UT muscle was recorded during five different step contractions of shoulder elevation force (10-30% maximal voluntary contraction) pre- and post-LLLT irradiation. The values of MFCV and sEMG global amplitude (RMS_G) were used to calculate the effects of LLLT. The results showed no difference in the MFCV comparing the LLLT and pLLLT groups (F = 0.72 p = 0.39, η _p² = 0.004). However, a significant difference was observed in the RMS_G between the LLLT and pLLLT (F _1,2 = 16.66; P < 0.0001, η _p² = 0.09). Individuals who received active LLLT presented a significant decrease in RMS_G after laser application (F = 61.28; p < 0.0001, η _p² = 0.43). In conclusion, the 820 nm LLLT, with energy total of 18 J, did not alter the MFCV but significantly reduced the sEMG signal amplitude of the upper trapezius muscle in healthy subjects to a level of up to 30% of maximal voluntary contraction.

Complementary medicine in chronic pain treatment

This article discusses several issues related to therapies that are considered "complementary" or "alternative" to conventional medicine. A definition of "complementary and alternative medicine" (CAM) is considered in the context of the evolving health care field of complementary medicine. A rationale for pain physicians and clinicians to understand these treatments of chronic pain is presented. The challenges of an evidence-based approach to incorporating CAM therapies are explored. Finally, a brief survey of the evidence that supports several widely available and commonly used complementary therapies for chronic pain is provided.

Neuroprotective Effects Against POCD by Photobiomodulation: Evidence from Assembly/Disassembly of the Cytoskeleton

Postoperative cognitive dysfunction (POCD) is a decline in memory following anaesthesia and surgery in elderly patients. While often reversible, it consumes medical resources, compromises patient well-being, and possibly accelerates progression into Alzheimer's disease. Anesthetics have been implicated in POCD, as has neuroinflammation, as indicated by cytokine inflammatory markers. Photobiomodulation (PBM) is an effective treatment for a number of conditions, including inflammation. PBM also has a direct effect on microtubule disassembly in neurons with the formation of small, reversible varicosities, which cause neural blockade and alleviation of pain symptoms. This mimics endogenously formed varicosities that are neuroprotective against damage, toxins, and the formation of larger, destructive varicosities and focal swellings. It is proposed that PBM may be effective as a preconditioning treatment against POCD; similar to the PBM treatment, protective and abscopal effects that have been demonstrated in experimental models of macular degeneration, neurological, and cardiac conditions.

Short-Term Effect of Laser Acupuncture on Lower Back Pain: A Randomized, Placebo-Controlled, Double-Blind Trial

Purpose. This trial was performed to investigate the efficacy of laser acupuncture for the alleviation of lower back pain. Methods. This was a randomized, placebo-controlled, double-blind trial. Fifty-six participants were randomly assigned to either the laser acupuncture group (n = 28) or the sham laser acupuncture group (n = 28). Participants in both groups received three treatment sessions over the course of one week. Thirteen acupuncture points were selected. The visual analogue scale for pain, pressure pain threshold, Patient Global Impression of Change, and Euro-Quality-of-Life Five Dimensions questionnaire (Korean version) were used to evaluate the effect of laser acupuncture treatment on lower back pain. Results. There were no significant differences in any outcome between the two groups, although the participants in both groups showed a significant improvement in each assessed parameter relative to the baseline values. Conclusion. Although there was no significant difference in outcomes between the two groups, the results suggest that laser acupuncture can provide effective pain alleviation and can be considered an option for relief from lower back pain. Further studies using long-term intervention, a larger sample size, and rigorous methodology are required to clarify the effect of laser acupuncture on lower back pain.

Role of rehabilitation medicine and physical agents in the treatment of cancer-associated pain

PURPOSE

To provide an overview of rehabilitation medicine- and physical modality-based approaches to cancer pain management, and to highlight the fact that these approaches are generally used in conjunction and that a majority are focused on minimizing pain during periods of mobility and the performance of activities of daily living.

METHODS

We performed a nonsystematic literature review and provide a description of the current standard of care.

RESULTS

Rehabilitative and physical modalities used to manage pain can be grouped into four categories: those that modulate nociception, stabilize or unload painful structures, influence physiological processes that indirectly influence nociception, or alleviate pain arising from the overloading of muscles and connective tissues that often occurs after surgery or with sarcopenia in late-stage cancer. Most modalities have been pragmatically refined over the years, and many have an evidence base, although few have been explicitly validated in the oncologic setting. With few exceptions, they are patient controlled and free of adverse effects.

CONCLUSION

Physical modalities and rehabilitation medicine offer a range of pain management approaches that may serve as beneficial adjuncts to the conventional systemic and interventional analgesic strategies used to control cancer-related pain. These approaches may be particularly beneficial to patients with movement-associated pain and those who are ambivalent regarding pharmacoanalgesia.

Effect of near-infrared light exposure on mitochondrial signaling in C2C12 muscle cells

Near-infrared (NIR) light is a complementary therapy used to treat musculoskeletal injuries but the underlying mechanisms are unclear. Acute NIR light treatment (~800-950 nm; 22.8 J/cm(2)) induced a dose-dependent increase in mitochondrial signaling (AMPK, p38 MAPK) in differentiated muscle cells. Repeated NIR light exposure (4 days) appeared to elevate oxidative stress and increase the upstream mitochondrial regulatory proteins AMPK (3.1-fold), p38 (2.8-fold), PGC-1α (19.7%), Sirt1 (26.8%), and reduced RIP140 (23.2%), but downstream mitochondrial regulation/content (Tfam, NRF-1, Sirt3, cytochrome c, ETC subunits) was unaltered. Our data indicates that NIR light alters mitochondrial biogenesis signaling and may represent a mechanistic link to the clinical benefits.

An ICON Overview on Physical Modalities for Neck Pain and Associated Disorders

INTRODUCTION

Neck pain is common, can be disabling and is costly to society. Physical modalities are often included in neck rehabilitation programs. Interventions may include thermal, electrotherapy, ultrasound, mechanical traction, laser and acupuncture. Definitive knowledge regarding optimal modalities and dosage for neck pain management is limited.

PURPOSE

To systematically review existing literature to establish the evidence-base for recommendations on physical modalities for acute to chronic neck pain.

METHODS

A comprehensive computerized and manual search strategy from January 2000 to July 2012, systematic review methodological quality assessment using AMSTAR, qualitative assessment using a GRADE approach and recommendation presentation was included. Systematic or meta-analyses of studies evaluating physical modalities were eligible. Independent assessment by at least two review team members was conducted. Data extraction was performed by one reviewer and checked by a second. Disagreements were resolved by consensus.

RESULTS

Of 103 reviews eligible, 20 were included and 83 were excluded. Short term pain relief - Moderate evidence of benefit: acupuncture, intermittent traction and laser were shown to be better than placebo for chronic neck pain. Moderate evidence of no benefit: pulsed ultrasound, infrared light or continuous traction was no better than placebo for acute whiplash associated disorder, chronic myofascial neck pain or subacute to chronic neck pain. There was no added benefit when hot packs were combined with mobilization, manipulation or electrical muscle stimulation for chronic neck pain, function or patient satisfaction at six month follow-up.

CONCLUSIONS

The current state of the evidence favours acupuncture, laser and intermittent traction for chronic neck pain. Some electrotherapies show little benefit for chronic neck pain. Consistent dosage, improved design and long term follow-up continue to be the recommendations for future research.

High power laser therapy treatment compared to simple segmental physical rehabilitation in whiplash injuries (1° and 2° grade of the Quebec Task Force classification) involving muscles and ligaments

INTRODUCTION

whiplash is a frequent post traumatic pathology caused by muscle, tendon and capsular elements over stretching. The authors conducted a short term prospective randomised study to test the effectiveness of a multi wave High Power Laser Therapy (HPLT) versus conventional simple segmental physical rehabilitation (PT) included in Italian tariff nomenclature performance physiotherapy Study Design: prospective randomised study (Level II).

MATERIAL AND METHODS

the authors identified 135 homogeneous patients with whiplash grade 1 - 2 of the Quebec Task Force classification (QTFC). INAIL, the Italian National Workers Insurance, based in Milan, was reliable source for identifying patients. All patients with whiplash injuries grade 1 or 2 QTFC, were eligible for the study, starting from April 28 2010 to September 30 2010. Patients referred to a Coordinator (C.M.) who applied the inclusion and exclusion criteria. Patients who agreed to participate were randomly assigned to one of the two treatment groups. Dates for initial treatment session were arranged, including cervical spine X-ray, and assessment. Each patient gave informed consent for participation and agreed to adopt only the study treatment for 6 weeks. Group A (84 patients) was treated with High Power Laser Therapy (HPLT), Group B (51 patients) received conventional simple segmental physical rehabilitation (PT). During the treatment period, no other electro-medical therapy, analgesics or anti-inflammatory drugs were allowed. All patients were assessed at baseline (T0) and at the end of the treatment period (T1) using a Visual Analogical Scale (VAS), (T2) the date of return to work was registered afterwards.

RESULTS

there was a reduction in VAS pain scores at T1. Group A (VAS = 20) Group B (VAS = 34,8) (p =0.0048). Laser treatment allowed quick recovery and return to work (T2). Group A after 48 days against 66 days of Group B (p=0.0005).

CONCLUSIONS

results suggest that High Power Laser Therapy - is an effective treatment in patients with whiplash injury, compared to conventional simple segmental physical rehabilitation.

Avoidable costs of physical treatments for chronic back, neck and shoulder pain within the Spanish National Health Service: a cross-sectional study

BACKGROUND

Back, neck and shoulder pain are the most common causes of occupational disability. They reduce health-related quality of life and have a significant economic impact. Many different forms of physical treatment are routinely used. The objective of this study was to estimate the cost of physical treatments which, despite the absence of evidence supporting their effectiveness, were used between 2004 and 2007 for chronic and non-specific neck pain (NP), back pain (BP) and shoulder pain (SP), within the Spanish National Health Service in the Canary Islands (SNHSCI).

METHODS

Chronic patients referred from the SNHSCI to private physical therapy centres for NP, BP or SP, between 2004 and 2007, were identified. The cost of providing physical therapies to these patients was estimated. Systematic reviews (SRs) and clinical practice guidelines (CPGs) for NP, BP and SP available in the same period were searched for and rated according to the Oxman and AGREE criteria, respectively. Those rated positively for ≥70% of the criteria, were used to categorise physical therapies as Effective; Ineffective; Inconclusive; and Insufficiently Assessed. The main outcome was the cost of physical therapies included in each of these categories.

RESULTS

8,308 chronic cases of NP, 4,693 of BP and 5,035 of SP, were included in this study. Among prescribed treatments, 39.88% were considered Effective (physical exercise and manual therapy with mobilization); 23.06% Ineffective; 13.38% Inconclusive, and 23.66% Insufficiently Assessed. The total cost of treatments was € 5,107,720. Effective therapies accounted for € 2,069,932.

CONCLUSIONS

Sixty percent of the resources allocated by the SNHSCI to fund physical treatment for NP, BP and SP in private practices are spent on forms of treatment proven to be ineffective, or for which there is no evidence of effectiveness.

Infrared (810-nm) low-level laser therapy on rat experimental knee inflammation

Arthritis of the knee is the most common type of joint inflammatory disorder and it is associated with pain and inflammation of the joint capsule. Few studies address the effects of the 810-nm laser in such conditions. Here we investigated the effects of low-level laser therapy (LLLT; infrared, 810-nm) in experimentally induced rat knee inflammation. Thirty male Wistar rats (230–250 g) were anesthetized and injected with carrageenan by an intra-articular route. After 6 and 12 h, all animals were killed by CO₂ inhalation and the articular cavity was washed for cellular and biochemical analysis. Articular tissue was carefully removed for real-time PCR analysis in order to evaluate COX-1 and COX-2 expression. LLLT was able to significantly inhibit the total number of leukocytes, as well as the myeloperoxidase activity with 1, 3, and 6 J (Joules) of energy. This result was corroborated by cell counting showing the reduction of polymorphonuclear cells at the inflammatory site. Vascular extravasation was significantly inhibited at the higher dose of energy of 10 J. Both COX-1 and 2 gene expression were significantly enhanced by laser irradiation while PGE₂ production was inhibited. Low-level laser therapy operating at 810 nm markedly reduced inflammatory signs of inflammation but increased COX-1 and 2 gene expression. Further studies are necessary to investigate the possible production of antiinflammatory mediators by COX enzymes induced by laser irradiation in knee inflammation.

Low power laser efficacy in the therapy of inflamed gingive in diabetics with parodontopathy

Background/Aim. There is clear evidence on direct relationship between periodontal disease and diabetes mellitus. Many investigations point out greater prevalence and severity of periodontal disease among diabetic patients. During last decade, low level laser therapy has been used in periodontal therapy. It has biostimulative effect, accelerates wound healing, minimizes pain and swelling, and there is almost no contraindication for its usage. The aim of the paper was to investigate the efficiency of low level laser therapy as adjuvant tool in reduction of gingival inflammation in diabetic patients. Methods. The study incuded 150 participants divided into three groups: group I (50 participants with diabetes mellitus type 1 and periodontal disease), group II (50 participants with diabetes mellitus type 2 and periodontal disease), group III (nondiabetic participants with periodontal disease). Gingival health evaluation was done using gingival index L?e-Silness. Soft and hard deposits were removed, periodontal pockets cleaned and GaAlAs low level laser therapy (5 mW) applied five consecutive days. In each patient, low level laser therapy was not applied on the left side of the jaw in order to compare the effects of the applied therapy. After the first, third and fifth therapy and one month after the last visit gingival index was evaluated. Before the first and after the fifth therapy exfoliative cytology of gingiva was done and nuclei areal was analyzed morphometrically. Results. After all investigated periods, gingival index and nuclei areal were significantly decreased comparing to values before the therapy, at both jaw sides (p < 0.001). After the 1st, 3rd and 5th therapy, the t-test showed a significantly decreased gingival index at the lased side of jaw comparing to non-lased side. Conclusion. Low level laser therapy is efficient in gingival inflammation elimination and can be proposed as an adjuvant tool in basic periodontal therapy of diabetic patients.

Effects of low-level laser therapy on pain and scar formation after inguinal herniation surgery: a randomized controlled single-blind study

OBJECTIVE

The aim of this study was to investigate the efficacy of an infrared GaAlAs laser operating with a wavelength of 830 nm in the postsurgical scarring process after inguinal-hernia surgery.

BACKGROUND

Low-level laser therapy (LLLT) has been shown to be beneficial in the tissue-repair process, as previously demonstrated in tissue culture and animal experiments. However, there is lack of studies on the effects of LLLT on postsurgical scarring of incisions in humans using an infrared 830-nm GaAlAs laser.

METHOD

Twenty-eight patients who underwent surgery for inguinal hernias were randomly divided into an experimental group (G1) and a control group (G2). G1 received LLLT, with the first application performed 24 h after surgery and then on days 3, 5, and 7. The incisions were irradiated with an 830-nm diode laser operating with a continuous power output of 40 mW, a spot-size aperture of 0.08 cm(2) for 26 s, energy per point of 1.04 J, and an energy density of 13 J/cm(2). Ten points per scar were irradiated. Six months after surgery, both groups were reevaluated using the Vancouver Scar Scale (VSS), the Visual Analog Scale, and measurement of the scar thickness.

RESULTS

G1 showed significantly better results in the VSS totals (2.14 +/- 1.51) compared with G2 (4.85 +/- 1.87); in the thickness measurements (0.11 cm) compared with G2 (0.19 cm); and in the malleability (0.14) compared with G2 (1.07). The pain score was also around 50% higher in G2.

CONCLUSION

Infra-red LLLT (830 nm) applied after inguinal-hernia surgery was effective in preventing the formation of keloids. In addition, LLLT resulted in better scar appearance and quality 6 mo postsurgery.

LPLI inhibits apoptosis upstream of Bax translocation via a GSK-3beta-inactivation mechanism

Low-power laser irradiation (LPLI), a non-damage physical therapy, which has been used clinically for decades of years, is shown to promote cell proliferation and prevent apoptosis. However, the underlying mechanisms that LPLI prevents cell apoptosis remain undefined. In this study, based on real-time single-cell analysis, we demonstrated for the first time that LPLI inhibits staurosporine (STS)-induced cell apoptosis by inactivating the GSK-3beta/Bax pathway. LPLI could inhibit the activation of GSK-3beta, Bax, and caspase-3 induced by STS. In the searching for the mechanism, we found that, LPLI can activate Akt, which was consistence with our former research, even in the presence of STS. In this anti-apoptotic process, the interaction between Akt and GSK-3beta increased gradually, indicating Akt interacts with and inactivates GSK-3beta directly. Conversely, LPLI decreased the interaction between GSK-3beta and Bax, with the suppression of Bax translocation to mitochondria, suggesting LPLI inhibits Bax translocation through inactivating GSK-3beta. These results were further confirmed by the experiments of co-immunoprecipitation. Wortmannin, an inhibitor of phosphatidylinositol 3'-OH kinase (PI3K), potently suppressed the activation of Akt and subsequent anti-apoptotic processes induced by LPLI. Taken together, we conclude that LPLI protects against STS-induced apoptosis upstream of Bax translocation via the PI3K/Akt/GSK-3beta pathway. These findings raise the possibility of LPLI as a promising therapy for neuron-degeneration disease induced by GSK-3beta.

Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials

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.

FUNDING

None.

Electrical acustimulation of the wrist for chronic neck pain: a randomized, sham-controlled trial using a wrist-ankle acustimulation device

OBJECTIVES

Chronic neck pain is a common problem and is treated using a variety of conservative treatments. This single-blind, randomized, sham-controlled trial investigated the value of adding electrical stimulation of acupuncture points on the wrist to a standardized program of neck exercises for chronic neck pain.

METHODS

At initial recruitment 60 patients were randomly assigned to receive either active or sham electrical stimulation of acupuncture points on the wrist in addition to standardized neck exercise. Active or sham wrist acustimulation was given for 30 minutes 2 times/wk over a period of 4 weeks. A 30 minutes program of standardized neck exercises was also performed simultaneously.

RESULTS

Forty-nine patients completed the study (22 active, 27 sham). Statistically significant improvements were found for acustimulation when compared with sham at immediate posttreatment and 1-month posttreatment for Numerical Rating Scale, Northwick Park Neck Pain Questionnaire and Pain Self-Efficacy Questionnaire. In active and sham electrical stimulation group 38.9% and 8.3% of patients reported a reduction of Numerical Rating Scale > 50% at 1-month posttreatment follow-up, respectively. All patients tolerated acustimulation and no adverse effects were reported.

DISCUSSION

Electrical acustimulation of the wrist administered as two, 30 minutes sessions /wk added value to standardized neck exercise for chronic neck pain. A 4-week course of treatment produced effects lasting 1-month posttreatment.

Effect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans

OBJECTIVE

To investigate if development of skeletal muscle fatigue during repeated voluntary biceps contractions could be attenuated by low-level laser therapy (LLLT).

BACKGROUND DATA

Previous animal studies have indicated that LLLT can reduce oxidative stress and delay the onset of skeletal muscle fatigue.

MATERIALS AND METHODS

Twelve male professional volleyball players were entered into a randomized double-blind placebo-controlled trial, for two sessions (on day 1 and day 8) at a 1-wk interval, with both groups performing as many voluntary biceps contractions as possible, with a load of 75% of the maximal voluntary contraction force (MVC). At the second session on day 8, the groups were either given LLLT (655 nm) of 5 J at an energy density of 500 J/cm2 administered at each of four points along the middle of the biceps muscle belly, or placebo LLLT in the same manner immediately before the exercise session. The number of muscle contractions with 75% of MVC was counted by a blinded observer and blood lactate concentration was measured.

RESULTS

Compared to the first session (on day 1), the mean number of repetitions increased significantly by 8.5 repetitions (+/- 1.9) in the active LLLT group at the second session (on day 8), while in the placebo LLLT group the increase was only 2.7 repetitions (+/- 2.9) (p = 0.0001). At the second session, blood lactate levels increased from a pre-exercise mean of 2.4 mmol/L (+/- 0.5 mmol/L), to 3.6 mmol/L (+/- 0.5 mmol/L) in the placebo group, and to 3.8 mmol/L (+/- 0.4 mmol/L) in the active LLLT group after exercise, but this difference between groups was not statistically significant.

CONCLUSION

We conclude that LLLT appears to delay the onset of muscle fatigue and exhaustion by a local mechanism in spite of increased blood lactate levels.

Evaluation of mitochondrial respiratory chain activity in muscle healing by low-level laser therapy

BACKGROUND

Recent studies demonstrate that low-level laser therapy (LLLT) modulates many biochemical processes, especially the decrease of muscle injures, the increase in mitochondrial respiration and ATP synthesis for accelerating the healing process.

OBJECTIVE

In this work, we evaluated mitochondrial respiratory chain complexes I, II, III and IV and succinate dehydrogenase activities after traumatic muscular injury.

METHODS

Male Wistar rats were randomly divided into three groups (n=6): sham (uninjured muscle), muscle injury without treatment, muscle injury with LLLT (AsGa) 5J/cm(2). Gastrocnemius injury was induced by a single blunt-impact trauma. LLLT was used 2, 12, 24, 48, 72, 96, and 120 hours after muscle-trauma.

RESULTS

Our results showed that the activities of complex II and succinate dehydrogenase after 5days of muscular lesion were significantly increased when compared to the control group. Moreover, our results showed that LLLT significantly increased the activities of complexes I, II, III, IV and succinate dehydrogenase, when compared to the group of injured muscle without treatment.

CONCLUSION

These results suggest that the treatment with low-level laser may induce an increase in ATP synthesis, and that this may accelerate the muscle healing process.

Treatment of neck pain: noninvasive interventions: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To identify, critically appraise, and synthesize literature from 1980 through 2006 on noninvasive interventions for neck pain and its associated disorders.

SUMMARY OF BACKGROUND DATA

No comprehensive systematic literature reviews have been published on interventions for neck pain and its associated disorders in the past decade.

METHODS

We systematically searched Medline and screened for relevance literature published from 1980 through 2006 on the use, effectiveness, and safety of noninvasive interventions for neck pain and associated disorders. Consensus decisions were made about the scientific merit of each article; those judged to have adequate internal validity were included in our best evidence synthesis.

RESULTS

Of the 359 invasive and noninvasive intervention articles deemed relevant, 170 (47%) were accepted as scientifically admissible, and 139 of these related to noninvasive interventions (including health care utilization, costs, and safety). For whiplash-associated disorders, there is evidence that educational videos, mobilization, and exercises appear more beneficial than usual care or physical modalities. For other neck pain, the evidence suggests that manual and supervised exercise interventions, low-level laser therapy, and perhaps acupuncture are more effective than no treatment, sham, or alternative interventions; however, none of the active treatments was clearly superior to any other in either the short- or long-term. For both whiplash-associated disorders and other neck pain without radicular symptoms, interventions that focused on regaining function as soon as possible are relatively more effective than interventions that do not have such a focus.

CONCLUSION

Our best evidence synthesis suggests that therapies involving manual therapy and exercise are more effective than alternative strategies for patients with neck pain; this was also true of therapies which include educational interventions addressing self-efficacy. Future efforts should focus on the study of noninvasive interventions for patients with radicular symptoms and on the design and evaluation of neck pain prevention strategies.

Low-level light stimulates excisional wound healing in mice

BACKGROUND

Low levels of laser or non-coherent light, termed low-level light therapy (LLLT) have been reported to accelerate some phases of wound healing, but its clinical use remains controversial.

METHODS

A full thickness dorsal excisional wound in mice was treated with a single exposure to light of various wavelengths and fluences 30 minutes after wounding. Wound areas were measured until complete healing and immunofluorescence staining of tissue samples was carried out.

RESULTS

Wound healing was significantly stimulated in BALB/c and SKH1 hairless mice but not in C57BL/6 mice. Illuminated wounds started to contract while control wounds initially expanded for the first 24 hours. We found a biphasic dose-response curve for fluence of 635-nm light with a maximum positive effect at 2 J/cm(2). Eight hundred twenty nanometer was found to be the best wavelength tested compared to 635, 670, and 720 nm. We found no difference between non-coherent 635+/-15-nm light from a lamp and coherent 633-nm light from a He/Ne laser. LLLT increased the number of alpha-smooth muscle actin (SMA)-positive cells at the wound edge.

CONCLUSION

LLLT stimulates wound contraction in susceptible mouse strains but the mechanism remains uncertain.

Low level laser therapy modulates kinin receptors mRNA expression in the subplantar muscle of rat paw subjected to carrageenan-induced inflammation

Low level laser therapy (LLLT) has been used clinically in order to treat inflammatory processes. In this work, we evaluated if LLLT alters kinin receptors mRNA expression in the carrageenan-induced rat paw edema. Experimental groups were designed as followed: A1 (Control-saline), A2 (Carrageenan-only), A3 (Carrageenan+laser 660 nm) and A4 (Carrageenan+laser 684 nm). Edema was measured by a plethysmometer. Subplantar tissue was collected for kinin receptors mRNA quantification by Real time-PCR. LLLT of both 660 and 684 nm wavelengths administrated 1 h after carrageenan injection was able to promote the reduction of edema produced by carrageenan. In the A2 group, B1 receptor expression presented a significantly increase when compared to control group. Kinin B1 receptor mRNA expression significantly decreased after LLLT's 660 or 684 nm wavelength. Kinin B2 receptor mRNA expression also diminished after both laser irradiations. Our results suggest that expression of both kinin receptors is modulated by LLLT, possibly contributing to its anti-inflammatory effect.

830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser

We report the formation of 830 nm (cw) laser-induced, reversible axonal varicosities, using immunostaining with beta-tubulin, in small and medium diameter, TRPV-1 positive, cultured rat DRG neurons. Laser also induced a progressive and statistically significant decrease (p<0.005) in MMP in mitochondria in and between static axonal varicosities. In cell bodies of the neuron, the decrease in MMP was also statistically significant (p<0.05), but the decrease occurred more slowly. Importantly we also report for the first time that 830 nm (cw) laser blocked fast axonal flow, imaged in real time using confocal laser microscopy and JC-1 as mitotracker. Control neurons in parallel cultures remained unaffected with no varicosity formation and no change in MMP. Mitochondrial movement was continuous and measured along the axons at a rate of 0.8 microm/s (range 0.5-2 microm/s), consistent with fast axonal flow. Photoacceptors in the mitochondrial membrane absorb laser and mediate the transduction of laser energy into electrochemical changes, initiating a secondary cascade of intracellular events. In neurons, this results in a decrease in MMP with a concurrent decrease in available ATP required for nerve function, including maintenance of microtubules and molecular motors, dyneins and kinesins, responsible for fast axonal flow. Laser-induced neural blockade is a consequence of such changes and provide a mechanism for a neural basis of laser-induced pain relief. The repeated application of laser in a clinical setting modulates nociception and reduces pain. The application of laser therapy for chronic pain may provide a non-drug alternative for the management of chronic pain.