ArticleLiterature Review

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

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Abstract

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. None.

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... PBM is mainly used for analgesic treatment [2] and is effective for both acute and chronic pain [3,4]. Metaanalyses have validated the efficacy of PBM in relieving clinically significant pain in many common diseases, including chronic neck pain [5], headache [6], postoperative pain [7], and tendinopathy [8]. In addition, PBM has few side effects [5,9] and is expected to be a complementary or alternative treatment to pharmaceutical-based therapies. ...
... Metaanalyses have validated the efficacy of PBM in relieving clinically significant pain in many common diseases, including chronic neck pain [5], headache [6], postoperative pain [7], and tendinopathy [8]. In addition, PBM has few side effects [5,9] and is expected to be a complementary or alternative treatment to pharmaceutical-based therapies. ...
... Histopathological evaluation by HE staining showed that direct laser irradiation at 1 W/cm 2 and 180 J/cm 2 did not damage the sciatic nerve, suggesting that the inhibition of neuronal firing was not due to an injury of the sciatic nerve by laser irradiation (Figure 6). PBM treatment has few side effects [9], for example, for neck pain [5] and stellate ganglion block [25], with no adverse events reported in each meta-analysis. Our data showing suppression of firing without producing nerve damage support these studies. ...
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Photobiomodulation has analgesic effects via inhibition of nerve activity, but few reports have examined the effects on the spinal dorsal horn, the entry point for nociceptive information in the central nervous system. In this study, we evaluated the effects of laser irradiation of peripheral nerve axons, which are conduction pathways for nociceptive stimuli, on the neuronal firing in lamina II of the spinal dorsal horn of a rat evoked by mechanical stimulation with von Frey filaments (vFF). In order to record neuronal firing, electrodes were inserted into lamina II of the exposed rat spinal dorsal horn. The exposed sciatic nerve axons were irradiated with an 808 nm laser. The 26.0 g vFF-evoked firing frequency was inhibited from 5 min after laser irradiation and persisted for 3 h. Sham irradiation did not alter the firing frequency. Laser irradiation selectively inhibited 15.0 and 26.0 g vFF-evoked firing, which corresponded to nociceptive stimuli. Histopathological evaluation revealed no damage to the sciatic nerve due to laser irradiation. These results indicate that neuronal firing is inhibited in lamina II of the spinal dorsal horn, suggesting that laser irradiation inhibits Aδ and/or C fibers that conduct nociceptive stimuli.
... No adverse effects, such as thermal burn at the treatment site associated with LED irradiation, were observed even 7 days after the irradiation. These results were consistent with previous systematic review and meta-analysis [14,15]. The effect size on pain relief assessed by VAS shown in the results of this study was a reduction of 18.1 mm, suggesting that this may be equivalent to the effect size of 19.7 mm shown in previous systematic reviews [15]. ...
... These results were consistent with previous systematic review and meta-analysis [14,15]. The effect size on pain relief assessed by VAS shown in the results of this study was a reduction of 18.1 mm, suggesting that this may be equivalent to the effect size of 19.7 mm shown in previous systematic reviews [15]. ...
... Our treatment device was safe to use, and reduced the subjective symptoms of neck and shoulder stiffness. Although the safety of LLLT has been proven in previous studies [15,[19][20][21], this LED irradiation treatment device may be safer than LLLT and thus likely to be competitive in healthcare markets. Indeed, LEDs emit broadband light that is not monochromatic, is less directional, and is noncoherent compared with lasers. ...
Article
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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.
... Accordingly, the effectiveness of LLLT in neck region in our meta-results was also non-substantial. LLLT reduces 19.86 mm in VAS in patients with neck disorders which is more than MCIC for non-specific neck pain as well as our results [27]. Considering the fact that physical therapy clinics do not use LLLT alone, it seems logical that the pure effect of LLLT on MNP without any modality and exercises is acceptable. ...
... However, these changes would not be perceivable for patients with MNP in daily and social activities. Both the dose per point and irritation time are important for the best outcomes of treatment [27]. Among RCTs that observed positive effects on outcomes, four studies used gallium arsenide (GaAs) laser; one study used helium-neon laser (He-Ne); and two studies used gallium aluminum arsenide (Ga-Al-As). ...
... Chow et al. showed that high heterogeneity came from different treatment settings among RCTs including dose per point and irritation time. However, the included RCTs with active control groups or different diagnoses of neck pain may increase the heterogeneity [27]. Kadhim-Saleh et al. meta-analyzed the effectiveness of LLLT by subgrouping the MNP in RCTs with placebo groups resulting in a diminished heterogeneity [17]. ...
Article
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Low-level laser therapy (LLLT) is one of recent modalities for treatment of myofascial neck pain (MNP). Several RCTs have been conducted on its effectiveness. The aim of this comprehensive meta-analysis was to evaluate the effectiveness of LLLT on MNP. Electronic databases were searched for identifying eligible studies comparing the effectiveness of LLLT using any wavelength with placebo or active control in myofascial neck pain up to June 2022. Data related to pain intensity, pain pressure threshold (PPT), range of motion (ROM), and disability was analyzed as a pooled estimate of mean difference or standard mean difference (SMD) with 95% confidence intervals (CIs) using random/fixed-effect model. Funnel plot and Egger’s linear regression test were also conducted to examine the risk of publication bias. A total of 13 randomized controlled trials were included in this systematic review and meta-analysis. The data assessing laser effectiveness on different outcomes of 556 patients were considered for meta-analysis. Pooled results revealed that LLLT was significantly effective in pain reduction (MD = − 1.29, 95% CI = − 2.36; − 0.23, P < 0.001). Also, secondary outcomes including PPT (SMD of 2.63, 95% CI = 0.96; 4.30, P < 0.01) and right bending ROM (SMD of 3.44, 95% CI = 0.64; 6.24, P < 0.01) were improved, while disability (MD of − 7.83, 95% CI = − 17.1; 0.08, P = 1.34) did not improve significantly after LLLT. Our meta-data revealed that LLLT may reduce myofascial neck pain and its related outcomes. LLLT is suggested to be used by clinicians along with other therapies such as manual and exercise therapy.
... pbMt found to have profound biological effects on tissue including increased cell proliferation, 14 accelerating the healing process, promoting tissue regeneration, preventing cell death, 15 anti-inflammatory activity 16 and relief of pain. 17 therapeutic exposure to low intensity of red and/or near infrared light is commonly referred to as "low intensity" because of its use of light at energy densities that are low compared to other forms of laser therapy that are used for ablation, cutting, and thermally coagulating tissue. 18 heat is a compounding limitation in achieving optimal phototherapeutic effects. ...
... pbMt can be indicated to temporary relief of minor muscle and joint pain, arthritis, and muscle spasm, relieving stiffness, promoting relaxation of muscle tissue, to temporarily increase local blood circulation where heat is indicated, symptomatic relief and management of chronic and intractable pain, adjunctive treatment for postsurgical, and post-trauma acute pain. there is evidence that pbMt has positive effects on decrease pain intensity in musculoskeletal conditions such as non-specific knee pain, 28 osteoarthritis, 29,30 fibromyalgia, 31-33 temporomandibular disorders, 34-36 neck, shoulder and back pain, 17,37,38 and also in management of pain after total hip replacements. 39 the use of pbMt in the abovementioned musculoskeletal conditions have a direct impact on decreased use of pharmacologic agents, including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. ...
... 55 however, there is strong evidence that pbMt reduces pain in patients with neck pain. a systematic review and meta-analysis 17 published in the renowned The Lancet included 16 rcts (N.=820) and assessed the efficacy of PBMT on neck pain. the authors concluded that pain is reduced immediately significant improvement in pain and function. ...
Article
Pain is the most common reason for physician consultations and the number one reason for missed work or school days is musculoskeletal pain. Pain management is utilized for easing the suffering and improving the quality of life of those living with chronic pain. Over the past several decades, physicians have become increasingly willing to prescribe opioids to manage pain. However, the opioid use can cause side effects as poor coordination, sedation, mood swings, depression, and anxiety combined with a dependence on the drugs. In the rehabilitation setting, patients benefit most when their health providers utilize a multimodal approach combining different types of therapies and when patients take on a significant role in optimal management of their own pain. The use of light as a therapeutic alternative form of medicine to manage pain and inflammation has been proposed to fill this void. Photobiomodulation therapy applied in the form of low-intensity light amplification by the stimulated emission of radiation (LASER) and lightemitting diode (LED) has been shown to reduce inflammation and swelling, promote healing, and reduce pain for an array of musculoskeletal conditions. There is evidence that photobiomodulation therapy reduces pain intensity in non-specific knee pain, osteoarthritis, pain post-total hip arthroplasty, fibromyalgia, temporomandibular diseases, neck pain, and low back pain. Therefore, the purpose of this review was to presented the up-to-dated evidence about the effects of lowintensity LASER and LED (photobiomodulation therapy) on pain control of the most common musculoskeletal conditions. We observed that the photobiomodulation therapy offers a noninvasive, safe, drug-free, and side-effect-free method for pain relief of both acute and chronic musculoskeletal conditions as well as fibromyalgia.
... Achieving an e ective pain management method without drug administration is a common goal of research in all areas of the health sciences [12,13]. For this reason, the use of laser has been increasingly frequent in dentistry, bringing bene ts to patients in various specialties, including orthodontics. ...
... is time can be considered an unfavorable factor in the orthodontic routine since it requires a considerable chair time. However, we must take into account the fact that it is a noninvasive therapy [12,41,42] and has no side effects comparing to nonsteroidal anti-inflammatory drugs [6,9,43]. erapy with nonsteroidal anti-inflammatory drugs is the method most used by orthodontists to control pain caused by fixed appliances [6]. ...
Article
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Purpose: There is no consensus about the mechanism and efficacy in alleviating pain of the lower-level laser therapy (LLLT) during orthodontic treatment. This study aimed to evaluate the LLLT effectiveness clinically in reducing pain caused by orthodontic movement that occurs in the early stages of treatment. Methods: The sample consisted of 54 patients in need of orthodontic treatment divided into two groups. A 28 experimental patients group (initial mean age: 26.84 years old) was undergone gallium-aluminum-arsenide infrared laser application on 12 points for each tooth immediately after the installation of the first alignment archwire, and a 26 patients control group (initial mean age: 29.13 years old) was undergone to no pain control intervention at all. Pain intensity was measured by using a visual analog scale, which was marked pain level (mm) reported in 06, 24, 48, and 72 hours. The perception of pain (beginning, peak, decline, and absence) was evaluated by filling up a questionnaire. To compare the intensity and perception of pain between groups, a nonparametric Mann-Whitney has been performed. Results: The experimental group showed levels (mm) at 6 (p < 0.001), 24 (p=0.004), and 48 hours (p=0.007) and perception of pain (hours) in the peak (p=0.026), decline (p=0.025), and absence (p=0.008) significantly lower compared to the group control. Conclusion: Low-level laser therapy is effective in reducing pain severity caused by orthodontic forces activation, and it promotes the analgesic action lasting effect during the most painful feeling time.
... There is evidence about the effects of PBMT alone to treat patients with chronic neck and shoulder pain. A systematic review and meta-analysis showed that pain intensity was reduced in these patients after treatment with PBMT alone [22]. This reduction remained up to 22 weeks after the end of the treatment. ...
... These findings are contrary to ours with regard to pain intensity. However, our results are in line with the best available evidence, through a systematic review with meta-analysis [22]. On the other hand, we observed that PBMT-sMF was not able to improve ROM, as well as the abovementioned study, suggesting that neither PBMT or PBMT-sMF have positive effects on ROM of patients with chronic neck and/or shoulder pain. ...
Article
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Photobiomodulation therapy (PBMT) has been used to treat patients with chronic neck and/or shoulder pain. However, it is unknown whether the concurrent use of PBMT and static magnetic field (PBMT-sMF) also has positive effects in these patients. The aim of this study was to investigate the effects of PBMT-sMF versus placebo on pain intensity, range of motion (ROM) and treatment satisfaction in patients with chronic nonspecific neck and/or shoulder pain. A randomized controlled trial, with blinded assessors, therapists and patients was carried out. Seventy-two patients with chronic nonspecific neck and/or shoulder pain were randomized to either active PBMT-sMF (n = 36) or placebo PBMT-sMF (n = 36). Patients were treated twice weekly, over 3 weeks. Primary outcome was pain intensity, measured 15 min after the last treatment session and at 24-, 48-, 72-h, and 7-days after the last treatment. Secondary outcomes were ROM, patient’ treatment satisfaction, and adverse effects. PBMT-sMF was able to reduce pain intensity in all time points tested compared to placebo (p < 0.05). There was no difference between groups in the secondary outcomes (p > 0.05). Our results suggest that PBMT-sMF is better than placebo to reduce pain in patients with chronic nonspecific neck and/or shoulder pain at short-term.
... It has been found to reduce inflammation and swelling after acute trauma 5 and reduce acute and chronic musculoskeletal pain. [5][6][7] In complex regional pain syndrome, a complication is occasionally seen after fracture, 8 PBMT had a significant effect on pain and edema. 9 Chauhan and Sarin found that PBMT reduces pain and risk of recurrences of symptoms in tibia stress fractures. ...
... Another interesting point is the mid-term and long-term effects of PBMT in subacute-and long-lasting disorders, which have been demonstrated previously in PBMT reviews of neck pain and knee osteoarthritis. 6,29 It is important to have in mind that the healing process in DRF is not resolved when the cast is removed, and that the therapeutic timewindow for PBMT is open for at least 2 months postinjury. Based on the dosage recommendations by the World Association for Laser Therapy, 30 we hypothesize that the optimal PBMT dose for irradiation in DRF should be a little higher than the 1.2 J per point we applied to this anatomical location. ...
Article
Objective: Many patients with distal radius fracture (DRF) experience pain and disability after removal of the cast. The aim of this study was to investigate if photobiomodulation therapy (PBMT) applied after cast removal provides an add-on effect to a home-based exercise program in rehabilitation after DRF. Methods: In this triple-blinded placebo-controlled trial, 50 patients with conservatively treated DRF were randomized to receive either active PBMT or placebo PBMT after cast removal in addition to a home-based exercise therapy program. The outcome measures were the Patient-Rated Wrist and Hand Evaluation (PRWHE) questionnaire, night pain (NP), and consumption of analgesic medication (AM) and were evaluated after cast removal at 4 (baseline), 8, 12, and 26 weeks after injury. NP and AM were also evaluated 7 weeks after injury (end of active/placebo PBMT). Results: There was a significant between-group difference in PRWHE scores in favor of active PBMT 8, 12, and 26 weeks after DRF. NP and consumption of AM were significantly lower in the active PBMT group from 7 to 26 weeks. There was a minimum clinically important improvement between the groups in favor of active PBMT in total score at 12 weeks, in pain subscore at 8, 12, and 26 weeks, and in disability subscore at 8 and 12 weeks. Conclusions: PBMT is safe and has long-term positive effect on pain and disability in DRF patients, when applied in combination with a home-based rehabilitation exercise program. Clinical Trial registration number: NCT03014024.
... These mechanisms include mechanotransductive processes, including the activation of opsins (light receptors), in particular, neuropsin/ kallikrein-8 (KLK8), which has been to shown to be gender specific, 32 porphyrins, 33 and melanin, 34 and neurotrophic signaling, and cytoskeleton modulation. 35,36 The local membrane and systemic effects of these nonvisual phototransduction cascades are also known to have gender-specific properties. Further, the well-known influence of gender differences in human health and disease such as cardiovascular disease, 14 AD, 37 Parkinson's disease, 38 and even life expectancy 39 further highlight the potential for the contribution of gender as a significant factor in treatment outcomes, including PBM therapy. ...
... One pathway through which PBM applies its effects is the neurotrophic signaling pathway in the modulation of cytoskeletons and long-range nonelectrical signaling. 35,36 A good example of the neurotrophic signaling is signaling involved in the brain-derived neurotrophic factor (BDNF) vesicle transport. BDNF Val66Met polymorphism is important in memory and behavior and adaptation to changes in the environment. ...
Article
Background: The influence of gender is significant in the manifestation and response to many diseases and in the treatment strategy. Photobiomodulation (PBM) therapy, including laser acupuncture, is an evidence-based treatment and disease prevention modality that has shown promising efficacy for a myriad of chronic and acute diseases. Anecdotal experience and limited clinical trials suggest gender differences exist in treatment outcomes to PBM therapy. There is preliminary evidence that gender may be as important as skin color in the individual response to PBM therapy. Aim: To conduct a literature search of publications addressing the effects of gender differences in PBM therapy, including laser acupuncture, to provide a narrative review of the findings, and to explore potential mechanisms for the influence of gender. Methods: A narrative review of the literature on gender differences in PBM applications was conducted using key words relating to PBM therapy and gender. Results: A total of 13 articles were identified. Of these articles, 11 have direct experimental investigations into the response difference in gender for PBM, including laser acupuncture. A variety of cadaver, human, and experimental studies demonstrated results that gender effects were significant in PBM outcome responses, including differences in tendon structural and mechanical outcomes, and mitochondrial gene expression. One cadaver experiment showed that gender was more important than skin tone. The physiologic mechanisms directing gender differences are explored and postulated. Conclusions: The review suggests that to address the requirements of a proficient precision medicine-based strategy, it is important for PBM therapy to consider gender in its treatment plan and dosing prescription. Further research is warranted to determine the correct dose for optimal gender treatment, including gender-specific treatment plans to improve outcomes, taking into account wavelength, energy exposure, intensity, and parameters related to the deliverance of treatment to each anatomical location.
... Our nding is inconsistent with those of authors who suggested that PBM yielded only able to initiate a positive bone-tissue response or a transient effect and not maintained for a long time [19,20]. Similar to our results, Chow et al. [21] observed that PBM reduces pain in acute neck pain and that these effects are maintained in patients with chronic neck pain for a long time (up to 22 weeks) after the treatment ends. ...
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Study Design: A quasi-experimental (matched-pair-design)study. Patients received local photobiomodulation(LPBM) on one side of their body and the control group was assigned to other side, at the same locations. Objectives: To evaluate the LPBM effects on bone-mineral-density(BMD), in complete spinal-cord-injury(C.SCI) patients with osteoporosis(OP) by follow-up dual-energy X-ray-absorptiometry(DEXA). Setting: The clinic of Mazandaran University of Medical Science, Sari, Iran Methods: A total of 23 locations consisting of three-therapeutic-locations(TTLs): Forearm-MID, proximal-femur(PFe), proximal-tibia(PTib), in eight patients (except, forearm-MID with seven) were included LPBM treatment for 8 weeks. BMD were measured using DEXA in both side, at Week-8 of LPBM and at Week-15 for follow-up. Different doses were adjusted depending on the anatomical distance between the skin surface and bone depth as determined by sonography to deliver the optimal isodose at each depth for bone. This study used data from TTLs: Forearm-MID, PFe and PTib to analyze as subgroup effects. We also assessed serum 25-OH-Vitamin-D(Total) during the baseline and Week-8 of treatment Results: BMD, statistically increased at Week-8 of LPBM and at Week-15 for follow-up compared with control group. Subgroup analysis showed, a statistically significant effect of LPBM on BMD, in both PFe and forearm MID, compared with their control, but not at the PTib. A statistically significant, increase in serum 25(OH)-Vitamin-D was found between Week-8 of LPBM treatment and baseline. Conclusion: LPBM with an 830nm laser provided an appropriate dose calculation considering the depth is effective in increasing BMD in C.SCI patient with OP and can lead to a favorable effect on vitamin-D metabolism.
... [15][16][17] Two systematic studies have shown the effect of LLLT in reducing neck pain and patient recovery over 22 weeks. 18,19 In contrast, some review studies have found that LLLT is ineffective in treating neck pain. 20 Considering the prevention of unnecessary surgery, the use of safe and minimally invasive methods, the benefits of using the therapeutic effects of LLLT, and the existence of conflicting views on the use of LLLT in the treatment of non-specific chronic neck pain, this study is the first attempt to evaluate the effect of LLLT in the treatment of patients with non-specific chronic neck pain in the Iranian population. ...
Article
Introduction: The most common type of neck pain is chronic nonspecific pain. There are conflicting opinions about the beneficial effects of a low-level laser in reducing chronic nonspecific neck pain. The aim of this study was to evaluate the efficacy of low-level laser therapy (LLLT) for the treatment of non-specific chronic neck pain. Methods: This study was conducted as a prospective randomized clinical trial. Forty-four patients were randomly divided into two groups: (1) Intervention group (n=22): LLLT in the red spectra range with a wavelength of 980 (nm) and a power of 16 (J/cm2 ) was irradiated in the affected areas of the neck, the muscles along the spine, and the upper trapezius; (2) sham group (n=22): A low-level laser was irradiated with a passive probe (non-laser red light) in the affected areas of the neck, the muscles along the spine, and the upper trapezius. The treatment protocol consisted of 12 sessions (15 minutes, three times a week, for four weeks). These patients were evaluated for pain using the visual analog scale (VAS) (0-10). The patients were followed up for four weeks. Results: This study showed a statistically significant reduction in chronic nonspecific neck pain in the LLLT group (P<0.05). Conclusion: It is concluded that LLLT was effective in reducing chronic nonspecific neck pain. LLLT is a non-invasive, safe and effective method that can improve chronic nonspecific neck pain in patients in the short term.
... The analgesic properties of PBMt, beyond the resolution of cortical coherence and brain wave pattern disruptions, are supported by a wealth of data that provide insight into the possible delivery of pre-emptive PBMt in the prevention and development of persistent pain [221], including neuropathic pain [87] chemotherapies [222], neck pain [223], low back pain [224], and pain following nerve or spinal cord injury [225]. Hypothetically, reversible cytoskeletal disruption may modulate pain by disruption of cytoskeletal and microtubular structures to physically interrupt ATP delivery and block neuronal depolarization to limit afferent signaling to the dorsal horn and through the disruption of fast axonal flow and limiting the transport of pro-inflammatory cytokines, as is evident via the appearance of dendritic varicosities. ...
Article
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Despite a significant focus on the photochemical and photoelectrical mechanisms underlying photobiomodulation (PBM), its complex functions are yet to be fully elucidated. To date, there has been limited attention to the photophysical aspects of PBM. One effect of photobiomodulation relates to the non-visual phototransduction pathway, which involves mechanotransduction and modulation to cytoskeletal structures, biophotonic signaling, and micro-oscillatory cellular interactions. Herein, we propose a number of mechanisms of PBM that do not depend on cytochrome c oxidase. These include the photophysical aspects of PBM and the interactions with biophotons and mechanotransductive processes. These hypotheses are contingent on the effect of light on ion channels and the cytoskeleton, the production of biophotons, and the properties of light and biological molecules. Specifically, the processes we review are supported by the resonant recognition model (RRM). This previous research demonstrated that protein micro-oscillations act as a signature of their function that can be activated by resonant wavelengths of light. We extend this work by exploring the local oscillatory interactions of proteins and light because they may affect global body circuits and could explain the observed effect of PBM on neuro-cortical electroencephalogram (EEG) oscillations. In particular, since dysrhythmic gamma oscillations are associated with neurodegenerative diseases and pain syndromes, including migraine with aura and fibromyalgia, we suggest that transcranial PBM should target diseases where patients are affected by impaired neural oscillations and aberrant brain wave patterns. This review also highlights examples of disorders potentially treatable with precise wavelengths of light by mimicking protein activity in other tissues, such as the liver, with, for example, Crigler-Najjar syndrome and conditions involving the dysregulation of the cytoskeleton. PBM as a novel therapeutic modality may thus behave as “precision medicine” for the treatment of various neurological diseases and other morbidities. The perspectives presented herein offer a new understanding of the photophysical effects of PBM, which is important when considering the relevance of PBM therapy (PBMt) in clinical applications, including the treatment of diseases and the optimization of health outcomes and performance.
... Physiotherapy can play an important role in the treatment of patients with chronic cervical pain, as it seeks to minimize pain, recover mobility, and strengthen the muscles, providing an improvement in quality of life [7][8][9][10][11]. For this, resources such as photobiomodulation are applied, with the use of low level laser therapy (LLLT), which is characterized by monochromaticity, collimation, spatial and temporal coherence, producing a non-invasive treatment, painless and capable of providing biomodulatory effects on living organisms [12], with anti-inflammatory, pro-repair and analgesic actions [13,14]. in turn, a light emitting diode (LEd) is a diode that emits monochromatic radiation, but not coherent; however, it apparently also presents anti-inflammatory, healing, and pain mitigation properties, similar to LLLT [15][16][17][18]. Since some equipment currently takes the form of a cluster in which there are associated LEds and LLLTs, the objective of this study was to evaluate the joint use of these tools in the treatment of individuals with chronic non-specific cervicalgia, aiming at reducing the pain. ...
... In tissue regeneration, in turn, evidence demonstrates effectiveness both in superficial lesions and in deeper tissues (90) , proving to be efficient in the proliferation of fibroblasts, in the synthesis and organization of collagen, and the induction of neovascularization (91,92) . In sports medicine, the effects of photobiomodulation on the muscular system are increasingly robust, with emphasis on the increase in resistance to fatigue, strength, and recovery speed of athletes (93)(94)(95)(96) as well as its effectiveness in cervical and muscle pain relief (97) . ...
Article
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This text is the continuation of the XVIII SBFa Congress publication. In part “A” we presented the analyses on clinical vocal evaluation. Part “B” focuses on vocal rehabilitation: 4. Traditional techniques of vocal therapy; 5. Modern techniques of electrostimulation and photobiomodulation applied to vocal rehabilitation. The numerous studies on the various programs, methods, and techniques of traditional rehabilitation techniques, and many with high quality of evidence, allow us to consider such procedures relatively well described, safe, and with known effects, accounting for the treatment of various vocal disorders. The scientific evidence with traditional techniques is recognized worldwide. New fronts of evolution, with electrostimulation or photobiomodulation used to handle voice problems, seem to be promising as coadjutant approaches. There are more studies on electrostimulation in vocal rehabilitation than with photobiomodulation; however, scientific evidence for these two modern techniques is still limited. Knowledge and caution are required for the application of either technique. Keywords Voice; Voice Disorder; Voice Training; Therapy; Vocal Rehabilitation
... Na regeneração tecidual, por sua vez, as evidências demonstram eficácia tanto em lesões superficiais como também em tecidos mais profundos (90) , mostrando-se eficiente na proliferação de fibroblastos, na síntese e organização de colágeno e na indução de neovascularização (91,92) . Na medicina esportiva os efeitos da fotobiomodulação sobre o sistema muscular são cada vez mais robustos, com destaque para o aumento da resistência à fadiga, da força e da velocidade de recuperação dos atletas (93)(94)(95)(96) bem como sua eficácia no relaxamento cervical e alívio da dor muscular (97) . ...
Article
This text is the continuation of the XVIII SBFa Congress publication. In part "A" we presented the analyses on clinical vocal evaluation. Part "B" focuses on vocal rehabilitation: 4. Traditional techniques of vocal therapy; 5. Modern techniques of electrostimulation and photobiomodulation applied to vocal rehabilitation. The numerous studies on the various programs, methods, and techniques of traditional rehabilitation techniques, and many with high quality of evidence, allow us to consider such procedures relatively well described, safe, and with known effects, accounting for the treatment of various vocal disorders. The scientific evidence with traditional techniques is recognized worldwide. New fronts of evolution, with electrostimulation or photobiomodulation used to handle voice problems, seem to be promising as coadjutant approaches. There are more studies on electrostimulation in vocal rehabilitation than with photobiomodulation; however, scientific evidence for these two modern techniques is still limited. Knowledge and caution are required for the application of either technique.
... Photobiomodulation leads to the emission of photons that reach the mitochondria, increasing energy synthesis (ATP), and the cell membranes of fibroblasts, keratinocytes and endothelial cells, allowing the absorption of light energy by cellular chromophores and converting it into chemical kinetic energy inside the cell [10,11], resulting in the formation of numerous blood vessels, thus improving the amount of oxygen in the tissues, in the increased production of granulation tissue, stimulating muscle relaxation and thus contributing to the analgesic effects of laser therapy [12,13]. And with this acceleration of microcirculation, cytokines are released that reduce the inflammatory reaction, and the reabsorption of edema, eliminating the accumulation of intermediate metabolites [14]. ...
... The constant technological evolution in the area of rehabilitation, observed mainly in the areas of osteoarthritis [11], fibromyalgia [12], Parkinson [13], temporomandibular disorders [14], facial paralysis [15] and adhesive capsulitis [16], developed by our research group at the Biophotonics Laboratory of the Instituto de Física de São Carlos has marked the improvement in quality of life of patients affected by different diseases Photobiomodulation, through therapeutic laser, allows the absorption of light stimulus through cytochrome C chromophores, which stimulates a response for each type of lesion, promoting the release of histamine, serotonin, bradykinin, prostaglandins, with changes in the action enzyme, promoting increased energy synthesis (ATP), which favors the reduction of pain, inflammation and tissue repair [17,18]. Therapeutic ultrasound acts due to the effect of it longitudinal waves, ...
... Photobiomodulation leads to the emission of photons that reach the mitochondria, increasing energy synthesis (ATP), and the cell membranes of fibroblasts, keratinocytes and endothelial cells, allowing the absorption of light energy by cellular chromophores and converting it into chemical kinetic energy inside the cell [10,11], resulting in the formation of numerous blood vessels, thus improving the amount of oxygen in the tissues, in the increased production of granulation tissue, stimulating muscle relaxation and thus contributing to the analgesic effects of laser therapy [12,13]. And with this acceleration of microcirculation, cytokines are released that reduce the inflammatory reaction, and the reabsorption of edema, eliminating the accumulation of intermediate metabolites [14]. ...
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The increase in repetitive strain injuries in recent years has led to the emergence of an epidemic character, which has become a very prevalent health problem in the contemporary world. This increase in cases comes from factors related to these pathologies directly linked to the modernization of work. As a means of intervention, this work presents the synergy of photobiomodulation and myofascial release. The myofascial release technique, which consists of a type of massage, which applies a deep slide, muscle compressions and frictions on the skin that act by mobilizing the muscle fascia. Photobiomodulation has direct action with analgesic and anti-inflationary emphasis, as well as the formation of greater amounts of energy, helping diseased cells and organisms to return to homeostasis. Five patients were treated with pain in the cervical spine, shoulder, trapeze, elbow and carpal tunnel regions. The protocol used consisted of 10 treatment sessions, twice a week, for 15 minutes each session, using an 808nm therapeutic laser. The Disabilities of the arm, shoulder and hand questionnaire (DASH) and Visual Analogue Scale (VAS) were used. There was a great evolution in the values of The Disabilities of the arm, shoulder and hand questionnaire and Visual Analogue Scale, showing that the proposed treatment is an efficient, non-invasive and non-pharmacological form of treatment.
... LLLT focuses on irradiation over the skin at specific traditional Chinese medicine acupuncture points or at muscular trigger points [50]. Although no identified studies have assessed the effectiveness on CPPS, LLLT has been shown to improve syndromes such as low back pain [50], neck pain [51], painful diabetic neuropathy [52], and pelvic pain associated with primary dysmenorrhea [53,54]. ...
Article
Chronic pelvic pain syndrome (CPPS) is a functional pain disorder characterized by ongoing pain in the apparent absence of clinically identifiable causes. The prevalence of functional pain disorders demonstrates the importance of adequate management of ongoing symptomatology, but due to the uncertain etiology and myriad patient presentation phenotypes, reliable treatment options are difficult to implement. New interventions involving non-pharmacological approaches to pain management have been investigated across a spectrum of clinical and pre-clinical studies. Given that conservative care such as exercise, counseling, and musculoskeletal therapy is widely recommended as first-line treatment for CPPS, an updated review of these and related methodologies are needed. Familiarizing physicians and the public with the newest evidence for complementary and alternative medicine (CAM) and other conservative care treatments will assist with the promotion of evidence-based practices in a safe and reliable manner. This review aimed to summarize the current evidence and proposed mechanisms for non-pharmacological treatment specific to CAM and management of chronic pelvic pain centered on neuromusculoskeletal focused intervention such as acupuncture, auriculotherapy, manipulation, manual therapy, myofascial release, and phototherapy. The discussion suggests that reported improvements in pelvic pain or related symptomatology may be attributed to changes in the peripheral inflammasome and somatic origins of peripheral sensitization. Robustness of the included clinical studies is discussed throughout the review, and attention is paid to delineating inclusion criteria of formally diagnosed CPPS compared to general pelvic or abdominal pain. Overall, this review consolidates the current state of evidence regarding the utilization of non-traditional interventions using CAM techniques for the management of chronic pelvic pain and recommends a future direction for the field.
... [16][17][18] Focused PBM has demonstrated positive results when treating a multitude of acute and chronic pain conditions. [19][20][21][22][23][24][25][26][27][28][29][30][31][32] The therapy has received recent recognition from national and international healthcare governing bodies in treatment of cancer-related painful oral mucositis. 16 It is traditionally delivered by a trained therapist using a small probe applied to specific painful areas; as such, sessions can take up to 90 min in widespread pain conditions such as FM. ...
Article
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Introduction Chronic pain conditions are a leading cause of disease and disability. They are associated with symptoms such as fatigue, sleep and mood disturbances. Minimal evidence is available to support effective treatments and alternatives treatment approaches are called for. Photobiomodulation therapy has been highlighted as one promising option. A whole-body therapy device (NovoTHOR) has recently been developed with a number of potential advantages for people with chronic pain. Research is needed to consider the feasibility of this device. Methods and analysis A single-centre single-armed (no placebo group) feasibility study with an embedded qualitative component will be conducted. The intervention will comprise 18 treatments over 6 weeks, with 6-month follow up, in the whole-body photobiomodulation device. A non-probability sample of 20 adult participants with a clinician diagnosis of chronic axial pain, polyarthralgia, myofascial pain, or widespread pain will be recruited (self- and clinician referral). Outcome measures will focus on acceptability of trial processes with a view to guiding a definitive randomised controlled trial. Analyses will utilise descriptive statistics for quantitative aspects. The qualitative element will be assessed by means of a participant-reported experience questionnaire post-intervention and semi-structured audio-recorded interviews at 3 stages; pre-, mid- and post-intervention. The latter will be transcribed verbatim and a reflexive thematic analysis will be used to identify emerging themes. Exploratory outcomes (participant-reported and performance-based measures) will be analysed according to data distribution. Ethics and dissemination The study has received ethical approval from the Leicester Central Research and Ethics Committee. Findings will be disseminated via local chronic pain groups, public register update, submission for presentation at scientific meetings and open-access peer-reviewed journals, and via academic social networks.
... In earlier studies, laser therapy was found to be effective in relieving pain associated with several conditions such as knee injuries, shoulder pain, fibromyalgia, chronic arthritis, carpal tunnel syndrome, and tendonitis [32,33]. A systematic review reported that acute neck pain decreased immediately after laser therapy and up to 22 weeks after complete treatment [34]. ...
Article
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Athletes such as long-distance runners, sprinters, hockey, and/or football players may have proximal hamstring tendinopathy (PHT). Laser therapy has been shown to be effective in tendinopathies. High power laser therapy (HPLT) is used for the treatment of several musculoskeletal conditions; however, its efficacy on PHT has not been investigated. This study is aimed at examining the effects of HPLT on pain and isokinetic peak torque (IPT) in athletes with PHT. The two-arm comparative pretest-posttest experimental design was used with random allocation of 36 athletes aged 18-35 years into two groups (experimental and conventional group). The experimental group included the application of HPLT for 3 weeks. The conventional group included treatment with a conventional physiotherapy program including ultrasound therapy, moist heat pack, and home exercises for a total of 3 weeks. Pain and IPT of the hamstring muscle were measured before and after the application of the intervention. Pain score decreased, and IPT increased significantly (p < 0:05) after application of HPLT, by 61.26% and 13.18%, respectively. In the conventional group, a significant difference (p < 0:05) was observed in pain scores only, which decreased by 41.
... It also seems that does not interfere with medications. At the tissue level, it has a major role in the stimulation of wound healing, reducing inflammation, edema, and pain and relieving some neurological problems [11], [12]. At the cellular level, it is used to induce differentiation of stem cells, to increase or to inhibit cell proliferation, to change the activity of cells, and to induce cell death [13]- [16]. ...
Article
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Photobiomodulation therapy (PBMT) or Low level light Therapy (LLLT), is the stimulatory effect of light on the cell behavior. It has been considered as a potential therapeutic intervention. Glioblastoma is a malignant primary brain tumor without any effective treatment. This in vitro study investigated the effect of PBMT on proliferation rate and vital activity of human glioblastoma U87 cell line. Three different wavelengths were considered: 632 nm (red light, 2.1 mW/cm2 ), 534 nm (green light, 1.2 mW/cm2), and 457 nm (blue light, 6.5 mW/cm2). The cell behavior was studied during a period of four hours up to 60 hours after irradiation. The irradiated cells were inspected by different assays for cell count, cell viability, cell death, and free radical production rate and were compared with the control non-irradiated ones. The results show a reduction in cell viability for all the three wavelengths. However, the effect is more pronounced for blue light. Cell death assessments, staining and flow cytometry, and NBT assay shows that blue light is not lethal, but that it reduces the free radical production rate. Temporal analysis shows that the maximum effect on cell proliferation will be observed around 48 hours after irradiation. It could be concluded that light, particularly shorter wavelengths, has an inhibitory effect on the in vitro proliferation rate of U87 cell line by affecting the energetics of the cell. The effect is stimulatory and persistent for periods comparable to cell doubling time. http://ijop.ir/article-1-438-en.html
... Low-level laser therapy (LLLT) is the use of laser device light for therapeutic purposes with an output range of 5-500 mW. There are evidence that LLLT stimulates tissue regeneration, relieves pain and reduces inflammation [14,15,16]. The laser light is typically of limit spectral width in the red and near-infrared (NIR) spectrum [17]. ...
Article
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The aim of this study was to evaluate the influence of pre-exercise muscle irradiation with various low-level laser therapy (LLLT) wavelengths and doses on skeletal muscle performance and fatigue after muscle contractions in in-situ mouse model using gastrocnemius muscle. Thirty-nine Swiss mice were arbitrarily allocated into control group and twelve LLLT irradiated groups receiving one of four different laser doses in the range 0.25-3.0 J from one of three wavelengths (637, 785 and 1064 nm) at one point on the gastrocnemius muscle before the fatigue protocol induced by electrical stimulation. Skeletal muscle fatigue was defined by fatigue index, half-relaxation time and force-time integration for all the 140 muscle contractions. At the 70th contraction, five laser irradiated groups (637 nm 0.5 J, 785 nm 0.5 J, 785 nm 0.75 J, 1064 nm 0.5 J and 1064 nm 1.5 J) had a significant difference (P<0.05) in terms of fatigue index. While, at the 140th contraction, only 637 nm 0.5 J and 1064 nm 0.5 J groups significantly differ (P<0.05) from control group. In term of half-relaxation time and force-time integration, there was no significant difference. These results indicate that LLLI has both wavelength and dose dependent effects on the gastrocnemius muscle and LLLI at appropriate wavelengths and dosage can enhance skeletal muscle performance and delays muscle fatigue.
... Nonetheless, it is prudent to point out that from its very first description by Endre Mester in the late 1960s of the photostimulatory effects on wound healing to the current clinical practice guidelines for oncotherapy-associated oral mucositis, PBM therapy has persistently demonstrated clinical benefits [4][5][6]. In fact, the evidence from systematic reviews and meta-analyses of controlled human clinical studies and rigorously done lab animal models explicitly demonstrates the safety and efficacy of PBM therapy for a broad range of ailments such as back or neck pain, tendinitis, arthritis, and mucositis, among others [7][8][9][10][11][12][13][14]. While the precise mechanistic basis of PBM in these breadths of ailments continues to be explored, evidence from these clinical phenotypes forms an unequivocal basis for its clinical utilization [15]. ...
Article
Multiple wavelength devices are now available for Photobiomodulation (PBM) treatments, but their dosimetry for individual or combinatorial use remains unclear. The present work investigated the effects of 447 nm, 532 nm, 658 nm, 810 nm, 980 nm, and 1064 nm wavelengths on odontoblast differentiation at 10 mW/cm2 using either equal treatment time for conventional fluence (300 sec for 3 J/cm2) or varying times to adjust for individual wavelength photon fluence (4.6 p.J/cm2). Both 447 and 810 nm significantly increased alkaline phosphatase (ALP) activity, while 1064 nm showed reduced ALP activity at 3 J/cm2. However, ALP induction was significantly improved when equivalent photon fluence dosing was used. Other wavelengths did not show significant changes compared to untreated controls. This data suggests that accounting for wavelength‐specific photon energy transfer during PBM dosing could improve clinical safety and efficacy. This article is protected by copyright. All rights reserved.
... Several studies have documented LLLA as a promising modality in pain management [26,27]. Over the last three years, five reviews favoured LLLT in pain management thanks to its safety, efficacy, and clinical effectiveness [28][29][30][31][32]. However, there is no consolidated evidence of LLLA use in SNP management in this special study population; more studies are needed to provide timely insight. ...
Article
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Background Shoulder and neck pain (SNP) is common in office workers and represents a serious public health problem given its detrimental impact on quality of life, physical functioning, personal finances, employers, and the health care system. Management with painkillers has adverse implications such as tolerance, addiction, and opioid abuse. Safe, sustainable, cost-effective, and evidence-based solutions are urgently needed. The non-invasive, painless, non-infectious, and safe modality of low-level laser acupuncture (LLLA) has shown promise for SNP management. Objective The overarching aim of this study is to provide evidence of the feasibility and therapeutic efficacy of LLLA for office workers with SNP. Methods This is a pilot, single-blind, double-armed, randomised controlled trial on the feasibility and therapeutic efficacy of a two-week LLLA therapy for office workers with SNP, aged 18 to 65 years. Each of the two study groups will contain 35 participants: the intervention group will receive LLLA from a licensed acupuncturist at the researchers’ university clinic (10–20 min/session, 3 sessions/week) for two weeks; the control group will receive usual care without painkillers. Outcomes will be measured at baseline, throughout the two-week intervention, and at trial end. Surveys including open-ended questions will be completed. The primary outcome of this study is to evaluate the feasibility of a two-week LLLA therapy for office workers with SNP, as measured by recruitment and completion rates, patient safety, and treatment adherence and compliance. Participants’ attitudes, motivation, and challenges to participation, intervention non-compliance, and experience of participating in the trial will be investigated via qualitative data. The secondary outcome is to evaluate the therapeutic efficacy of LLLA on SNP using the visual analogue scale (VAS) and the Short-Form McGill Pain Questionnaire (SF-MPQ); the work productivity and activity assessment (WPAI:SHP); 12-Item Short Form Survey (SF-12) for quality of life assessment; and the past 3-month out-of-pocket (OOP) cost for prescription and non-prescription SNP therapy, which is an indicative of the economic burden of SNP on patients and health care systems. This study was approved by Edith Cowan University’s Human Research Ethics Committee (No. 2021-02225-WANG). Results Data collection will commence in December 2021 with anticipated completion by December 2022. Conclusions Safe, sustainable, cost-effective, evidence-based interventions are needed to minimise the negative implications of SNP in office workers. LLLA is a promising modality in managing SNP. However, more consolidated evidence is required to provide insight regarding the effectiveness of LLLA. This study is expected to contribute to the challenging work of reducing the burden of SNP in office workers. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12621000426886p; https://www.anzctr.org.au/ACTRN12621000426886p.aspx
... 7,8,18,44,52 Phototherapy is a nascent approach that has been shown to reduce chronic back, neck, and neuropathic pain without any significant side effects reported so far. 9,11,14,19,21,42 In addition to low-level laser therapy, several preclinical and clinical studies have suggested the application of light-emitting diodes (LEDs) for the treatment of various conditions involving acute nociceptive and chronic pain. 10,12,16,27,[30][31][32]40,[45][46][47]53 Although most studies have focused on the use of red and infrared light, few preclinical and clinical studies have explored the use of lower wavelength light. ...
Article
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Introduction: Chronic pain is a frequent severe disease and often associated with anxiety, depression, insomnia, disability, and reduced quality of life. This maladaptive condition is further characterized by sensory loss, hyperalgesia, and allodynia. Blue light has been hypothesized to modulate sensory neurons and thereby influence nociception. Objectives: Here, we compared the effects of blue light vs red light and thermal control on pain sensation in a human experimental pain model. Methods: Pain, hyperalgesia, and allodynia were induced in 30 healthy volunteers through high-density transcutaneous electrical stimulation. Subsequently, blue light, red light, or thermal control treatment was applied in a cross-over design. The nonvisual effects of the respective light treatments were examined using a well-established quantitative sensory testing protocol. Somatosensory parameters as well as pain intensity and quality were scored. Results: Blue light substantially reduced spontaneous pain as assessed by numeric rating scale pain scoring. Similarly, pain quality was significantly altered as assessed by the German counterpart of the McGill Pain Questionnaire. Furthermore, blue light showed antihyperalgesic, antiallodynic, and antihypesthesic effects in contrast to red light or thermal control treatment. Conclusion: Blue-light phototherapy ameliorates pain intensity and quality in a human experimental pain model and reveals antihyperalgesic, antiallodynic, and antihypesthesic effects. Therefore, blue-light phototherapy may be a novel approach to treat pain in multiple conditions.
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Little is known about alternative treatment options for rhinosinusitis (RS). We aimed to evaluate the efficacy of low-level laser therapy (LLLT) for RS in experimentally induced rabbit models of RS. A total of 18 rabbits were divided into four groups: a negative control group (n = 3), an RS group without treatment (n = 5, positive control group), an RS group with natural recovery (n = 5, natural recovery group), and an RS group with laser irradiation (n = 5, laser-treated group). Computed tomography and histopathological staining were performed for each group. mRNA and protein expression levels of local cytokines (IFN-γ, IL-17, and IL-5) were also measured. Tissue inflammation revealed a significant improvement in the laser-treated group compared with the RS and natural recovery groups (p < 0.01). In addition, sinus opacification in the CT scans and cytokine expression was reduced in the laser-treated group, though without statistical significance. LLLT could be an effective option for the management of RS concerning radiological, histological, and molecular parameters.
Article
Chronic wounds have become one of the major issues in medicine today, the treatments for which include dressing changes, negative pressure wound therapy (NPWT), hyperbaric oxygen, light irradiation, surgery, etc. Nevertheless, the application of diode lasers in chronic wounds has rarely been reported. This retrospective cohort study aimed to evaluate the therapeutic effect of diode laser (810nm) irradiation on chronic wounds. 89 patients were enrolled in the study. The control group (41 patients) received traditional dressing change therapy, while the diode laser treatment group (48 patients) were patients received additional treatment with diode laser (810 nm) irradiation for 10 minutes at each dressing change. Wound healing time was compared between two groups, while the pain relief index was creatively introduced to evaluate the effect of relieving wound pain, which was calculated by the difference in pain scores between the first and last dressing changes divided by the number of treatment days. The wound healing time of the diode laser treatment group was 22.71±8.99 days, which was significantly shorter than that of the control group (37.44±23.42 days). The pain relief index of the diode laser treatment group was 0.081±0.055, which was significantly increased compared with that of the control group (0.057±0.033). Our findings suggest that diode laser irradiation has the potential to promote healing in chronic wounds and relieve wound pain. This article is protected by copyright. All rights reserved.
Article
The aim of this work was to characterize and describe the effect of High Intensity Laser Therapy (HILT) used in the treatment of chronic osteoarthritis in horses. Over a 2 year period, 11 horses with diagnosed bone spavin were treated with HILT as a monotherapy. The horses chosen for this report presented hind limb lameness, were positive in a spavin flexion test and showed improvement after intra-articular anesthesia of the tarsometatarsal joint. Additionally, all the horses presented radiological signs of tarsus osteoarthritis and had not been treated for bone spavin for a minimum of 6 months. Each horse received 10 HILT therapies over 14 days’ treatment time with the same laser protocol. At post-treatment orthopedic examination, four horses (36%) had improved two lameness grades (in the five-grade American Association of Equine practitioners lameness scale), four horses (36%) had improved one lameness grade and three horses (28%) did not improve. Additionally, three horses were totally sound after HILT. Post-treatment spavin test result improvement was observed in five horses (45%), and six horses (55%) showed the same spavin test grade as before treatment. There were no horses that were sound in the spavin test performed after HILT. Therefore, it seems probable that the application of HILT in horses suffering from bone spavin may decrease joint pain, which influences visual lameness reduction.
Chapter
This chapter discusses various physical modalities used in the management of acute and chronic pain of various etiologies. The modalities covered in this chapter include therapeutic ultrasound (ultrasound diathermy and high-intensity focused ultrasound), extracorporeal shockwave therapy, transcranial magnetic stimulation, low level laser therapy, and millimeter waves therapy. Historical aspects, physiology, proposed mechanisms of action, efficacy, and potential drawbacks are addressed.KeywordsPhysical rehabilitationPhysical factorsUltrasound therapeuticDiathermyMagnetic stimulationLow intensity laser
Article
Patients with long-term or severe inflammatory bowel disease (IBD) are more likely to develop colorectal cancer. The mortality rate of patients with IBD-related colorectal cancer is also higher than that of patients with common colorectal cancer. This study focused on the effect of photobiomodulation (PBM) on dextran sulfate sodium (DSS)-induced colitis and its underlying mechanism. C57 mice were treated with monochromatic light during DSS-induced colitis. Blue light irradiation clearly alleviated DSS-induced colitis, significantly changed the proportion of the relevant immune cell population in the colon, and improved the inflammatory environment of the colon. Moreover, the rhythm gene Brain And Muscle ARNT-Like 1 (Bmal1) is involved in the progression of colitis, and its decreased expression in colitis mice was reversed by blue light irradiation. These data demonstrated that the protective effect of blue light against colitis is mediated by the Bmal1-mediated pathway in macrophages. This study proposes blue light irradiation with specific light intensities as a potential IBD therapy.
Article
Objective: To investigate the effect of intravascular laser irradiation of blood (ILIB) in patients with post-stroke disability. Background: Helium-neon intravascular laser at a wavelength of 632.8 nm has been applied in post-stroke rehabilitation for many years in Taiwan. Data were collected from our practice to validate its effectiveness. Materials and methods: This was a single-center, retrospective, observational study. Data from 34 patients with first-episode ischemic stroke who participated in the post-acute care program and had an initial modified Rankin Scale (mRS) score of 4 between July 2018 and June 2021 were retrospectively reviewed. Twelve patients who received conventional rehabilitation plus ILIB were in the ILIB group. Twenty-two patients who received conventional rehabilitation only were in the control group. Assessments, including the mRS, Barthel Index (BI), Berg Balance Scale (BBS), six-minute walk test (6MWT), and Fugl-Meyer Assessment of the upper extremity (FMA-UE), were performed to evaluate any post-treatment improvement. Results: Patients who received ILIB had significantly superior mRS scores than those who received only conventional rehabilitation (p = 0.028). Patients in the ILIB group experienced more improvements in the BI, 6MWT, and FMA-UE; however, these were nonsignificant. In addition, the control group experienced a greater improvement in the BBS than the ILIB group. Further studies are required to elucidate the mechanism of action of ILIB therapy fully. There was no major adverse event reported in patients receiving ILIB therapy. Conclusions: ILIB improved independence in post-stroke patients, suggesting that ILIB is a promising treatment for facilitating post-stroke recovery.
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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.
Article
Low-Level laser therapy (LLLT), known as photobiomodulation therapy, stimulates the mitochondrial respiratory chain and causes changes in cellular adenosine triphosphate or cyclic adenosine monophosphate levels. Lasers are classified according to their power, maximum exposure, and wavelength. The dose required to treat the tissue; it depends on wavelength, power density, tissue type, tissue condition, pigmentation, depth of target tissue and treatment technique. Lasers are a useful treatment in human and veterinary rehabilitation. Studies showing that cartilage properties are preserved with treatment, improvement in peripheral nerve injuries, and that they contribute to pain management in patients with osteoarthritis are promising for their use in veterinary rehabilitation.
Chapter
The optical phenomena and physicochemical processes triggered by the light-matter interaction enable multiple applications of semiconductor nanomaterials and optoelectronic devices in the photomedicine field. Remarkably, quantum dot (QD) materials are considered highly attractive as individual platforms for multimodal applications, and for the development of wearable optoelectronic devices with medical applications. QDs are semiconductor nanocrystals with a radius below the corresponding Bohr radius, exhibiting electronic transitions that resemble an atom’s behavior. The most remarkable properties of QDs are their size-tunable emission wavelength, high photoluminescence quantum yield (PL-QY), wide absorption bandwidth, narrow emission bandwidth linked to narrow particle size distribution, and photostability. These unique optical properties along with the mature QD-based technologies have encouraged new applications. Among the most attractive applications of individual QD platforms is their use as fluorescent probes and efficient energy donors in photodynamic therapy (PDT). On the other hand, QD light-emitting diodes (QLEDs) are the QD-based devices attracting most of the attention for multiple applications in the health-care and photomedicine fields. The recent results of QLED-based in vitro studies in PDT and photobiomodulation (PBM) demonstrated the high potential of QLEDs as alternative and cost-effective photomedical light sources. Moreover, the QLEDs’ capability for flexible form factors, with simultaneous high power density (PD) and narrow emission bandwidth at clinically relevant red wavelengths, makes them strong candidates for use as light sources that would facilitate wider clinical adoption of PDT and PBM treatments. The photomedical markets include but are not limited to the management of cancer treatment, periodontal disease, dermatology, and chronic wound and ulcer care. The fundamentals of QD materials, QD devices, and phototherapies of high relevance are explained in the first section. This section includes the properties and synthesis of QDs, the evolution and operating principle of QLEDs, and the basics and benefits of PDT and PBM treatments. Subsequently, different types of QDs proposed for light-based theranostic applications are summarized. The next section is dedicated to the development and photomedical application of QD devices, especially QLEDs. This starts with the recent advances in red-emitting QLEDs, followed by the explanation of the most relevant radiometric parameters for phototherapy administration and for the evaluation of the QLEDs as efficient photomedical light sources. Later, the unique features and advantages of flexible QLEDs as alternative photomedical light sources and the results of QLED-based in vitro studies in PDT and PBM are presented. These studies are presented in parallel with the recent photomedical studies using organic light-emitting diodes (OLEDs) as light sources. A perspective about the future of QLEDs in and beyond the current photomedical research areas, along with conceptual designs of QLED-based medical devices, is also discussed. Ultimately, some examples of QD-based devices proposed for health monitoring and diagnostics are given. The latter applications could be included in the other branch of photomedicine that uses light for health monitoring and detecting disease.
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Understanding the compartment fire behavior has a vital importance for fire protection engineers. For design purposes, whether to use a prescriptive code or performance based on design, life safety and property protection issues are required to be assessed. The use of design fires in computer modelling is the general method to determine fire safety. However, these computer models are generally limited to the input of one design fire, with consideration of the complex interaction between fuel packages and the compartment environment being simplified. Of particular interest is the Heat Release Rate, HRR, as this is the commonly prescribed design parameter for fire modelling. If the HRR is not accurate then it can be subsequently argued that the design scenario may be flawed. Therefore, the selection of the most appropriate fire design scenario is critical, and an increased level of understanding of compartment behavior is an invaluable aid to fire engineering assumptions. This thesis studies 3 types of pool fire geometry to enhance the understanding of the impact and interaction that the size and location of pool fires within an enclosure have upon the compartment fire behavior, also Ethanol pool fires were used. In this present work, we have carried out to analysis the effect of water to extinguish the fire and it and it's tested in 4 different ways with and without water. Also in the result, we can see the effect of water to visibility and also the concentration of air.
Article
Objective The purpose of this study was to compare the effect of low-power laser therapy, dry needling, and exercise therapy on treating patients with neck and back pain and a diagnosis of the myofascial trigger points in the upper trapezius muscle. Methods A randomized clinical trial was conducted in Isfahan, Iran, in 2019. The study sample (78 participants) was randomly allocated to 3 groups of 26, including stretching exercises (3 times a day for 2 weeks, control group), low-power laser (3 sessions for 2 weeks, 6 J/cm², mean power of 100 MW in each point), and dry needling (4 sessions, with 25 × 0.25-mm needles). For all patients, the visual analog scale (VAS), neck disability index (NDI), and shoulder pain and disability index (SPDI) were completed at baseline, immediately, and 1 month after treatment. Results Final participants in this study (n = 60) consisted of 33 (55%) female patients and 27 (45%) male patients, with a mean age of 51.25 ± 7.94 years. In the exercise group, VAS, NDI, and SPDI scores were not remarkably different in the studied periods (P > .05). Moreover, a notable decrease in VAS, NDI, and SPDI scores were observed in the treatment intervals. However, by excluding the effect of the control group, no substantial difference was observed between the 2 treatments (P > .05). Conclusion The use of laser therapy and dry needling methods induced a rapid response to pain relief. There was no difference between the 2 forms of treatment in the short term.
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Transcranial photobiomodulation therapy (PBMT) also known as low-level laser therapy (LLLT) relies on the use of red/NIR light to stimulate, preserve and regenerate cells and tissues. In this review, we will present the most important laser types and sources used in the treatment of the brain, required energy densities to provide treatment, and laser delivery techniques to the brain through the cranium, eye, internal ear, and nostril. Various forms of light therapy have been practiced all over the world for many years. Among them, laser therapy has flourished in recent years. More and more laser equipment is being used in this area. The use of PBMT for neuronal stimulation has been studied in various animal and human models and has been shown to improve cerebral metabolic activity and blood flow and provide neuroprotection through anti-inflammatory and antioxidant pathways. In recent years, the concept of thermotherapy for the treatment of brain tumors has become more widespread. Traditionally, heat therapy is divided into hyperthermia, with a moderate increase in the temperature of the treated tissue above the physiological baseline level, and heat ablation, in which even higher temperatures are reached. Recently, intranasal light therapy, light delivery to the brain through the ear and other channels have become attractive and potential treatments for brain diseases. Here we summarize the various methods of delivering light through the nostrils and ear canals using lasers or light-emitting diodes (LEDs), which can be used alone or in combination with transcranial devices or (applied directly to the scalp) to treat a wide range of brain conditions such as the lungs cognitive impairment, Alzheimer's disease, Parkinson's disease, cerebrovascular disease, depression and anxiety, and insomnia. Evidence shows that low-intensity laser therapy improves blood rheology and cerebral blood flow, so there is no need to pierce blood vessels.
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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 (Ca ²⁺ ) 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 Ca ²⁺ dynamics was reduced by PBMT, contributing to its anti-hyperalgesic effects.
Article
Background: Effects of pulse irradiation with a 10–W semiconductor laser on pressure pain threshold and temporal summation were examined. Methods: The subjects were 10 healthy adults. All subjects were participated in both irradiation and sham groups. The irradiation group, 10–W semiconductor laser were applied to thenar eminence of non–dominant hand. The sham group was sham irradiated. Pressure pain threshold and temporal summation at the laser irradiated site were measured before and after irradiation. Results: The pressure pain threshold value showed a significant increase after 10–W semiconductor laser irradiation only in the irradiation group, but visual analogue scale value reflecting the temporal summation did not change in the both groups. Conclusion: We conclude that 10–W semiconductor laser irradiation increased the pressure pain threshold. On the other hand, under the conditions of this study, 10–W semiconductor laser irradiation did not affect the temporal summation.
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This study aimed to investigate how the combined use of low-level laser therapy (LLLT) and exercise, to reduce the possible side effects and/or increase the benefits of exercise, would affect oxidative stress, utrophin, irisin peptide, and skeletal, diaphragmatic, and cardiac muscle pathologies. In our study, 20 mdx mice were divided into four groups. Groups; sedentary and placebo LLLT (SC), sedentary and LLLT (SL), 30-min swimming exercise (Ex), and 30-min swimming exercise and LLLT (ExL). After 8 weeks of swimming exercise, muscle tests, biochemically; oxidative stress index (OSI), utrophin and irisin levels were measured. Skeletal, diaphragmatic and cardiac muscle histopathological scores, skeletal and cardiac muscle myocyte diameters were determined under the light and electron microscope. While only irisin levels were increased in group SL compared to SC, it was determined that OSI, heart muscle histopathological scores decreased and irisin levels increased in both exercise groups (p < 0.05). In addition, in the ExL group, an increase in rotarod and utrophin levels, and a decrease in muscle and diaphragm muscle histopathological scores were observed (p < 0.05). It was determined that the application of swimming exercise in the mdx mouse model increased the irisin level in the skeletal muscle, while reducing the OSI, degeneration in the heart muscle, inflammation and cardiopathy. When LLLT was applied in addition to exercise, muscle strength, skeletal muscle utrophin levels increased, and skeletal and diaphragmatic muscle degeneration and inflammation decreased. In addition, it was determined that only LLLT application increased the level of skeletal muscle irisin.
Chapter
Photobiomodulation is the emission of low intensity light to locally induce cells to equilibrium. One of its possible applications is for skin wound healing. However, any such solution must be non-contact because on the contrary it can cause pain and make the treatment unfeasible. Here we propose a device capable of emitting red light through LEDs to treat this type of injury in a non-contact way. In addition to assessing the optimal irradiation distance and estimating a maximum area of homogeneous coverage, we compared seven different configurations to assess the temperature stability during the treatment application. We tried two values of power density for the emission (50 \({\text {mW/cm}}^ {2}\) and 60 \({\text {mW/cm}}^ {2}\)) and two distance measurements (5 and 7 \({\text {cm}}\)) between LED boards and a temperature sensor, over a 10-min period. As a result of the optimal distance experiment, the 5 cm distance was used in the following two experiments, where at this distance it is possible to carry out applications covering a homogeneous area of up to 323.95 \({\text {cm}}^{2}\). In the temperature fluctuation experiment, we found that, although some configurations have less stability than the others, none of them compromises the efficiency of the treatment.KeywordsPhotobiomodulation therapyLEDSkinWounds
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The aim of this study was to evaluate the participation of nitric oxide (NO) in the hypotensive and vasorelaxation effect induced by PBM using an aluminum gallium arsenide (AlGaAs) diode laser (660 nm). Male Wistar rats were treated with the inhibitor of nitric oxide synthase (l-NAME). A red laser (660 nm; 63 J/cm²; 56 s/point) was applied to the abdominal region at six different points. Thoracic aorta was dissected for vascular reactivity study, and a laser (660 nm; 96 J/cm²; 56 s) was applied after incubation with the NO donor DETA-NO, PBS, or hydroxicobalamin. Endothelial cells (HUVEC) were treated with DETA-NO or CuSO4, and then, PBM (63 J/cm²) was applied, and the nitric oxide was detected. Hypertensive l-NAME rats did not exhibit a decrease in blood pressure after PBM. PBM promoted vasodilation in the aorta isolated from normotensive rats, and less effect in the aorta of l-NAME rats and the addition of the NO donor, DETA-NO, promoted greater vasodilation by PBM in the aorta of l-NAME rats. In endothelial cells, an increase in NO, after PBM, was detected; however, with the addition of CuSO4, which catalyzes the decomposition of NO storage, there was no detection of NO after PBM. The results of this study demonstrate that the hypotensive and vasodilatory effect of PBM with a red laser at 660 nm is modulated by the release of nitric oxide from the storage.
Chapter
Photobiomodulation (PBM) is now over 50 years old and has recently started to gain more widespread acceptance within the medical community. Alleviation of the side effects of cancer therapy has so far been one of the most impressive applications of PBM and the focus of this chapter. I will cover the mechanism of action and ask whether the effects of PBM on cancer cells and tumors is more likely to be positive or negative. There are some ways that PBM could actually attack the cancer either directly or indirectly, or in combination with other cytotoxic therapies. Finally, I will summarize the clinical applications of PBM against such side effects as oral mucositis, radiation dermatitis, dysphagia, hyposalivation and xerostomia, taste alterations, trismus, head and neck lymphedema, and voice and speech alterations.
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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 (IR) 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. AII groups demonstrated significant reductions in pain over the duration of the study with those groups which received infrared (820 nm) laser at 1 J/cm2 and 5 J/cm2. demonstrating the most significant effects (p ‹ 0.001). Only those subjects who had active laser treatment experienced side effects. Results indicated that responses to LLLT at the parameters used in this study are subject to placebo and may be dependent on power output, dose and/or wavelength.
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We studied the depth of penetration and the magnitude of attenuation of 632.8nm and 904nm light in skin, muscle, tendon, and cartilagenous tissues of live anaesthetized rabbits. Tissue specimens were dissected, prepared, and their thicknesses measured. Then, each wavelength of light was applied. Simultaneously, a power meter was used to detect and measure the amount of light transmitted through each tissue. All measurements were made in the dark to minimize interference from extraneous light sources. To determine the influence of pulse rate on beam attenuation, the 632.8nm light was used at two predetermined settings of the machine; continuous mode and 100 pulses per second (pps), at an on:off ratio of 1:1. Similarly, the 904nm infra-red light was applied using two predetermined machine settings: 292 pps and 2,336 pps. Multiple regression analysis of the data obtained showed significant positive correlations between tissue thickness and light attenuation (p < .001). Student's t-tests revealed that beam attenuation was significantly affected by wavelength. Collectively, our findings warrant the conclusions that (1) The calf muscles of the New Zealand white rabbit attenuates light in direct proportion to its thickness. In this tissue, light attenuation is not significantly affected by the overlying skin, a finding which may be applicable to other muscles. (2) The depth of penetration of a 632.8nm and 904nm light is not related to the average power of the light source. The depth of penetration is the same notwithstanding the average power of the light source. (3) Compared to the 904nm wavelength, 632.8nm light is attenuated more by muscle tissue, suggesting that is is absorbed more readily than the 904nm wavelength or conversely that the 904nm wavelength penetrates more. Thus, wavelength plays a critical role in the depth of penetration of light.
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To investigate whether low-level laser therapy (LLLT) can reduce pain from tendinopathy, we performed a review of randomized placebo-controlled trials with LLLT for tendinopathy. The literature search for trials using LLLT published after 1980 was conducted on Medline, Embase, and the Cochrane Library, together with a hand-search of physiotherapy journals in English and Scandinavian languages. Validity assessment of each trial was done according to predefined criteria for location-specific dosage and irradiation of the skin directly overlying the affected tendon. The literature search identified 78 randomized controlled trials with LLLT, of which 20 included tendinopathy. Seven trials were excluded for not meeting validity criteria on treatment procedure or trial design. Twelve of the remaining 13 trials investigated the effect of LLLT for patients with subacute and chronic tendinopathy, and provided a pooled mean effect of 21% [95% confidence interval (CI) 5.9–36.1]. If results from only the nine trials adhering to assumed optimal treatment parameters were included, the mean effect over placebo increased to 32% (95% CI: 23.0–41.0). LLLT can reduce pain in subacute and chronic tendinopathy if a valid treatment procedure and location-specific dose is used.
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Objective: This pilot study was undertaken to test techniques of application of laser therapy, appropriate outcome measures and to determine effect sizes in order to facilitate the performance of a larger, clinical trial of laser therapy in chronic neck pain. Methods: We conducted a randomized double-blind, placebo-controlled study of low level laser therapy in 20 patients with chronic neck pain. The primary outcome measure was change in a 10 cm Visual Analogue Scale [VAS] for pain. Other measures used included a Self-Reported Improvement in pain [SRI], measured by a VAS, Short-Form 36 Quality-of-Life questionnaire [SF-36], Northwick Park Neck Pain Questionnaire [NPNPQ] and the McGill Pain Questionnaire [MPQ]. Measurements were taken at baseline, at the end of 7 weeks treatment and at 12 weeks from baseline. Results: We found a positive, pain-relieving effect in the treated group compared with those given placebo using the VAS [P < 0.039], SRI [P < 0.001], NPNPQ [P < 0.002] and the MPQ [P < 0.009]. The results of the SF-36 did not differ significantly between the two groups. Patients in the treated group experienced an average pain score improvement of 66.7% compared with 16.6% in the placebo group. Conclusion: Low-power laser therapy, at the parameters used in this pilot study, may provide a non-invasive, non-pharmaceutical therapy for chronic neck pain for patients in general practice. Further study of this technique in a large-scale trial would be justified on the basis of the findings of this pilot study.
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We studied the depth of penetration and the magnitude of attenuation of 632.8nm and 904nm light in skin, muscle, tendon, and cartilagenous tissues of live anaesthetized rabbits. Tissue specimens were dissected, prepared, and their thicknesses measured. Then, each wavelength of light was applied. Simultaneously, a power meter was used to detect and measure the amount of light transmitted through each tissue. All measurements were made in the dark to minimize interference from extraneous light sources. To determine the influ-ence of pulse rate on beam attenuation, the 632.8nm light was used at two predetermined settings of the machine; continuous mode and 100 pulses per second (pps), at an on:off ratio of 1:1. Similarly, the 904nm infra-red light was applied using two predetermined machine settings: 292 pps and 2,336 pps. Multiple regression analysis of the data obtained showed significant positive correlations between tissue thickness and light attenuation (p < .001). Student's t-tests revealed that beam attenuation was significantly affected by wavelength. Collectively, our findings warrant the conclusions that (1) The calf muscles of the New Zealand white rabbit attenuates light in direct proportion to its thickness. In this tissue, light attenuation is not significantly affected by the overlying skin, a finding which may be appli-cable to other muscles. (2) The depth of penetration of a 632.8nm and 904nm light is not related to the average power of the light source. The depth of penetration is the same notwithstanding the average power of the light source. (3) Compared to the 904nm wave-length, 632.8nm light is attenuated more by muscle tissue, suggesting that is is absorbed more readily than the 904nm wavelength or conversely that the 904nm wavelength penetrates more. Thus, wavelength plays a critical role in the depth of penetration of light.
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Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30
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This study aimed to investigate the effect of 830 nm low-level laser therapy (LLLT) on skeletal muscle fatigue. Ten healthy male professional volleyball players entered a crossover randomized double-blinded placebo-controlled trial. Active LLLT (830 nm wavelength, 100 mW output, spot size 0.0028 cm(2), 200 s total irradiation time) or an identical placebo LLLT was delivered to four points on the biceps humeri muscle immediately before exercises. All subjects performed voluntary biceps humeri contractions with a load of 75% of the maximum voluntary contraction (MVC) force until exhaustion. After active LLLT the mean number of repetitions was significantly higher than after placebo irradiation [mean difference 4.5, standard deviation (SD) +/- 6.0, P = 0.042], the blood lactate levels increased after exercises, but there was no significant difference between the treatments. We concluded that 830 nm LLLT can delay the onset of skeletal muscle fatigue in high-intensity exercises, in spite of increased blood lactate levels.
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Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (http://www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.
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Best evidence synthesis. To provide evidence-based guidance to primary care clinicians about how to best assess and treat patients with neck pain. There is a need to translate the results of clinical and epidemiologic studies into meaningful and practical information for clinicians. Based on best evidence syntheses of published studies on the risk, prognosis, assessment, and management of people with neck pain and its associated disorders, plus additional research projects and focused literature reviews reported in this supplement, the 12-member multidisciplinary Scientific Secretariat of the Neck Pain Task Force followed a 4-step approach to develop practical guidance for clinicians. The Neck Pain Task Force recommends that people seeking care for neck pain should be triaged into 4 groups: Grade I neck pain with no signs of major pathology and no or little interference with daily activities; Grade II neck pain with no signs of major pathology, but interference with daily activities; Grade III neck pain with neurologic signs of nerve compression; Grade IV neck pain with signs of major pathology. In the emergency room after blunt trauma to the neck, triage should be based on the NEXUS criteria or the Canadian C-spine rule. Those with a high risk of fracture should be further investigated with plain radiographs and/or CT-scan. In ambulatory primary care, triage should be based on history and physical examination alone, including screening for red flags and neurologic examination for signs of radiculopathy. Exercises and mobilization have been shown to provide some degree of short-term relief of Grade I or Grade II neck pain after a motor vehicle collision. Exercises, mobilization, manipulation, analgesics, acupuncture, and low-level laser have been shown to provide some degree of short-term relief of Grade I or Grade II neck pain without trauma. Those with confirmed Grade III and severe persistent radicular symptoms might benefit from corticosteroid injections or surgery. Those with confirmed Grade IV neck pain require management specific to the diagnosed pathology. The best available evidence suggests initial assessment for neck pain should focus on triage into 4 grades, and those with common neck pain (Grade I and Grade II) might be offered the listed noninvasive treatments if short-term relief is desired.
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To investigate if development of skeletal muscle fatigue during repeated voluntary biceps contractions could be attenuated by low-level laser therapy (LLLT). Previous animal studies have indicated that LLLT can reduce oxidative stress and delay the onset of skeletal muscle fatigue. 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. 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. 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.
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The effect of low level laser (GaAs) on lateral epicondylitis was investigated in a double-blind, randomized, controlled study. Thirty patients were assigned equally to a laser (n = 15) or a placebo laser (n = 15) group. All patients received eight treatments and were evaluated subjectively and objectively before, at the end of, and four weeks after treatment. Patients also completed a follow-up questionnaire on an average of five to six months after treatment. A significant improvement in the laser compared to the placebo group was found on visual analog scale (p = 0.02) and grip strength (p = 0.03) tests four weeks after treatment. In this study low level laser therapy was shown to have an effect over placebo; however, as a sole treatment for lateral epicondylitis it is of limited value. Further studies are needed to evaluate the reliability of our findings and to compare laser to other established treatment methods.
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For reliability of the pain threshold measurement there were measured first 390 trigger points of 22 healthy students twice at each point. The reliability of two different measurements was found to be perfect. Infrared (904 nm) laser therapy was compared to placebo laser at the trigger points. Our study tested eighteen patients (11 men and 7 women), with 31 active trigger points in the muscles of the infraspinatus, extensor carpi radialis, levator scapulae, trapezius and tibialis anterior. Trigger points were randomly managed by infrared laser (dose 1.5J/point and place laser. The study was carried out by double-blind and cross-over principle. The responses of the management were documented by the pain threshold meter measurements of these trigger points before and after the treatments, and then fifteen minutes later. The trigger points of the other side of the body were also measured from the same muscles. In the results there were observed highly significant changes between the laser and placebo groups immediately after the treatment, 0.97 (SE 0.16) kg/cm2 (p less than 0.001). The differences between these two treatments were greater after fifteen minutes of the therapy--1.87 (SE 0.30) kg/cm2 (p less than 0.001). At the non-treated trigger points, the significant increase of the values was seen after fifteen minutes (p less than 0.05). Our research study results suggest that infrared laser had an effect at the trigger points and that the treatment significantly increased the pain threshold.
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Neck pain is common in rheumatological practice. Assessment of outcome is difficult without objective measures. A neck pain questionnaire using nine five-part sections has been devised to overcome this problem. Forty-four rheumatology out-patients with neck pain were studied. Questionnaires were completed on days 0 and 3-5, and at 1 and 3 months. There was good short-term repeatability (r = 0.84, kappa = 0.62). Mean scores of each of the nine sections tended to rise with that of the pain section showing internal consistency. Questions on duration and intensity of pain were good indicators of a patient's global assessment. The questionnaire is easy for patients to complete, simple to score and provides an objective measure to evaluate outcome in patients with acute or chronic neck pain.
Article
Study Design. Best evidence synthesis. Objective. To identify, critically appraise, and synthesize literature from 1880 through 2006 on noninvasive interventions fer neck pain and its associated disorders. 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 non-invasive 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 non-invasive 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.
Article
Rat saphenous nerve was irradiated in vivo with an 830 nm, 60 mW continuous wave beam of a gallium aluminium arsenide (GaAlAs) diode laser for 6 s, 30 s, 60 s, and 120 s. An unirradiated group of animals served as control. Demonstrable sodium-potassium-adenosine trophosphatase (Na-K-ATPase) activity noticeably increased over the normal control level following 6 s irradiation, peaked at 15 s, increased following 30 s, and was inhibited to below normal level after 60 s and 120 s irradiation. Inorganic phophate release was measured as a biochemical indication of Na-K-ATPase activity: these results were echoed by histochemical analysis. Increased Na-K-ATPase activity in nerve tissue following low reactive level laser therapy (LLLT) may be associated with the pain attenuation process.
Conference Paper
Conclusions based on systematic reviews of randomized controlled trials are considered to provide the highest level of evidence about the effectiveness of an intervention. This overview summarizes the available evidence from systematic reviews on the effects of nonpharmacological and nonsurgical interventions for rheumatoid arthritis (RA). Systematic reviews of studies of patients with RA (aged > 18 years) published between 2000 and 2007 were identified by comprehensive literature searches. Methodological quality was independently assessed by 2 authors, and the quality of evidence was summarized by explicit methods. Pain, function, and patient global assessment were considered primary outcomes of interest. Twenty-eight systematic reviews were included in this overview. High-quality evidence was found for beneficial effects of joint protection and patient education, moderate-quality evidence was found for beneficial effects of herbal therapy (gamma-linolenic acid) and low-level laser therapy, and low-quality evidence was found for the effectiveness of the other interventions. The quality of evidence for the effectiveness of most nonpharmacological and nonsurgical interventions in RA is moderate to low.
Article
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.
Article
In the last decade the applications of the laser in surgery and medicine have increased dramatically. With the increase of indications has come a concomitant increase in possible classification of laser reactions, including the erroneous ‘low power laser ’, ‘high power laser’ and others. The author presents a classification which is based on the laser/tissue reaction rather than on the hardware used to produce the laser beam. Laser/tissue reactions fall into two broad groups. When the tissue reaction to absorption of the incident laser energy results in photodestruction of, or an irreversible photomodulated change to the tissue architecture, then the level of reaction is higher than the survival threshold of the target cells. The author refers to this as high reactive-level laser treatment (HLLT), or more generally as laser surgery. On the other hand, the level of tissue reactivity to very low incident power and energy densities is well below the cells’ survival threshold so that instead of being damaged the cells are directly activated by the low incident photon density. In this case the changes in the irradiated tissue are photoactive and reversible: the author refers to this group of reactions as low reactive-level laser therapy (LLLT), or more generally as laser therapy. In general when laser energy is incident on tissue, whether it is intended for laser surgery or laser therapy, it propagates into the target tissue in a wavelength-specific manner, but the resultant pattern, for example a HeNe laser viewed in a block of methylacrylate or an infrared laser viewed in vivo with a CCD camera, resembles very closely the shape of an apple. The author has used this basic apple shape and has modified it so that the ‘Laser Apple’ is capable of giving a range of information about the laser and its tissue effect, including the laser type, wavelength, output power, irradiated area, irradiation time and penetration depth: from these parameters the incident power and energy densities can be calculated. The apple itself can represent the scattering pattern and is capable of graphically demonstrating the range of tissue reactions which in turn give their name to the range of ‘Laser Apples’, such as the C-Apple (carbonization), V-Apple (vaporization) and A-Apple (activation).
Article
Certain crystals cause synovial tissue inflammation and variability of inflammatory indicators like plasmatic prostaglandin E2 (PGE2), fibrinogen (PF) and synovial tissue PGE2. We evaluated Helium-Neon Laser efficacy on PF, plasmatic PGE2 and synovial PGE2 and its ability to induce involution of anatomopathological (AP) lesions in induced granulomatose process, alone and combined with a meloxicam injection. Rats were assigned to five different treatment groups. 5 mW He-Ne Laser radiation (632.8 nm) and 8 J.cm2 energy density were used in the treated groups. PF and plasmatic PGE2 and synovial PGE2 levels decreased in granulomatose arthritis groups treated with low level laser therapy (LLLT) or with a meloxicam injection or a combination of both therapies; the differences being statistically significant (p<0.01), as compared with the non-treated control group. In the combination therapy group, involution of granulomatose inflammation was observed. We conclude that He-Ne laser treatment or meloxicam administration after experimentally induced inflammation, normalizes plasmatic PGE2 and fibrinogen levels, but produces similar histological lesions as non-treated controls.
Article
Seventy-one patients with acute cervical pain were randomized in two groups. Group A, 37 patients was irradiated with a pulsed GaAs diode laser, 904 nm, pulse width 200 nsec, pulse frequency 10,000 Hz peak power of 20 W, average power 40 mW, spot size 150 μm2 in area (incident power density of approximately 26 W/cm2), and an angle of divergence of 6°. The laser was applied in the point technique with a dose of 4 J/cm2 per point in the area of pain. Group B, 34 patients, was treated with sham irradiation with a deactivated laser system. Neither the patients nor the operator knew which group each patient was randomly assigned to. The use of analgesic drugs and physical therapy was excluded in both groups. Pain was evaluated through a linear colour scale. Laser treatment was considered effective when pain relief was more than 60%. The treatment was effective in 94.59% of patients in group A, and 38.24% of group B (P < 0.0019). The pain was relieved completely in 67.56% of patients in group A, and in 17.65% in group B. in patients in whom the response to the treatment was effective, the pain returned in the six months following treatment in 14.28% of group A but in 58.33 % of group B (P < 0.005). No side effects were observed These results suggest that GaAs laser radiation is an efficient and safe treatment for patients with acute cervical pain. Six years have passed since we incorporated the GaAs laser into our therapeutic arsenal and up to date we have irradiated more than two thousand patients with different kinds of pain and pain sites. The aim of this work is to evaluate the real therapeutic effect versus the placebo effect of laser therapy in patients with acute cervical pain in both the immediate effect and the possible latency of the pain relief with LLLT.
Article
Study Design. The development and testing of a new comprehensive measure of neck pain and disability, the Neck Pain and Disability Scale. Objectives. To provide an initial evaluation of the Neck Pain and Disability Scale’s reliability and validity. Summary of Background data. Although several measures exist for generalized pain and disability, none is specific for neck pain. More specific measurements should improve assessment of treatments and clinical research aimed at cervical pain syndromes. Methods. The Neck Pain and Disability Scale was designed using the Million Visual Analogue Scale as a template and consists of 20 items that assess neck pain. In this study, 100 patients with neck pain, 52 patients with lower back and leg pain, and 27 pain-free volunteers were rated by the Neck Pain and Disability Scale. In addition, a subset of the 47 patients with neck pain were rated by several other established psychometric instruments. Results. An item analysis showed a high degree of internal consistency among the 20 items on the Neck Pain and Disability Scale (r = 0.93), and face validity was established by comparing patients who had neck pain as well as lower back and leg pain with a pain-free group. The Neck Pain and Disability Scale scores correlated with the Oswestry Disability Questionnaire, the Pain Disability Index, and psychological measures of depression and neuroticism. Conclusions. The results suggest a highly reliable instrument for evaluating neck pain with at least four underlying dimensions. Further work to address the predictive validity of this new tool are under way.
Article
The purpose of the present study was to investigate the effect of the low power laser therapy on the acute inflammatory process. Male Wistar rats were used. The rat paw oedema was induced by sub-plantar injection of carrageenan, the paw volume was measured before and 1, 2, 3 and 4 h after the injection using a hydroplethysmometer. To investigate the mechanism action of the Ga–Al–As laser on inflammatory oedema, parallel studies were performed using adrenallectomized rats or rats treated with sodium diclofenac. Different laser irradiation protocols were employed for specific energy densities (EDs), exposure times and repetition rates. The rats were irradiated with the Ga–Al–As laser during 80 s each hour. The ED that produced an anti-inflammatory effect were 1 and 2.5 J/cm2, reducing the oedema by 27% (P<0.05) and 45.4% (P<0.01), respectively. The ED of 2.5 J/cm2 produced anti-inflammatory effects similar to those produced by the cyclooxigenase inhibitor sodium diclofenac at a dose of 1 mg/kg. In adrenalectomized animals, the laser irradiation failed to inhibit the oedema. Our results suggest that low power laser irradiation possibly exerts its anti-inflammatory effects by stimulating the release of adrenal corticosteroid hormones.
Article
A number of clinical studies have reported the efficacy of the 820 nm Gallium Aluminum Arsenide (GaAlAs) laser for the management of musculoskeletal pain, but its mode of action is not clear. The aim of this study was to investigate the effect of 820 nm GaAlAs at energy densities of 4 J/cm2 and 19 J/cm2 on prostaglandin E2 (PGE2) production by myoblast cultures undergoing stimulation with interleukin I alpha (IL-1). The differentiated C2C12 cultures were allocated randomly into 6 groups (6 samples per group). Each group, except the control and the IL-1 supplement groups, was jrradiated with 820 nm GaAIAs at energy densities of 4J/cm2 or 19 J/cm2 on three occasions. The irradiation was undertaken initially and at one hour and two hours. The difference in mean PGE2 at 12 hours among the 6 groups was statistically significantly different as compared by Analysis of Variance, p=0.0001. The result from Scheffe multiple comparison (p = 0.05) showed that the PGE2 production of the culture with IL-1 and the culture with IL-1 irradiated by 820 nm at 4 J/cm2 were higher than the control group. There was no statistically significant difference in PGE2 production among the control group, the laser-irradiated groups without IL-1 supplement and the IL-1 stimulation group irradiated by 820 nm at 19 J/cm2. The results indicate that IL-1 can stimulate PGE2 synthesis in differentiated C2C12 skeletal muscle cells. 820 nm laser irradiation at 19 J/cm2 was found to inhibit that mechanism, while the lower energy density (4 J/cm2) failed to inhibit PGE2 production.
Article
Publication bias, the phenomenon in which studies with positive results are more likely to be published than studies with negative results, is a serious problem in the interpretation of scientific research. Various hypothetical models have been studied which clarify the potential for bias and highlight characteristics which make a study especially susceptible to bias. Empirical investigations have supported the hypothesis that bias exists and have provided a quantitative assessment of the magnitude of the problem. The use of meta-analysis as a research tool has focused attention on the issue, since naive methodologies in this area are especially susceptible to bias. In this paper we review the available research, discuss alternative suggestions for conducting unbiased meta-analysis and suggest some scientific policy measures which could improve the quality of published data in the long term.
Article
Objectives. An empirical, head-to-head comparison of the performance characteristics of four generic health status measures. Methods. The Nottingham Health Profile, the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36), the COOP/WONCA charts, and the EuroQol instrument were simultaneously employed in a controlled survey measuring the impact of migraine on health status. The feasibility (number of missing cases per item), internal consistency (Cronbach's α), construct validity (correlation patterns and common factor analysis), and discriminative ability (Receiver Operating Characteristic analyses) of the four measures were investigated. Results. The Nottingham Health Profile produced the lowest missing value rate. The internal consistency of the Nottingham Health Profile scales was lower than the scales of the SF-36. Combined factor analyses with data of the four instruments together resulted in two-factor solutions with a physical and a mental factor, explaining approximately 50% of variance. The SF-36 exhibited the best ability to discriminate between groups. Test-retest reliability and sensitivity to change over time could not be tested because of the cross-sectional character of the study. Conclusions. None of the instruments performed uniformly as "best" or "worst." Purely on the basis of the results of the psychometric analyses, the SF-36 appeared to be the most suitable measure of health status in this relatively healthy population. In general, the choice of the most suitable instrument for generic health status assessment in a particular study should be guided by the special features of each candidate instrument under consideration.
Article
Patients of more than 60 years of age and affected by chronic low back pain were randomly assigned to two groups. Group A, consisting of 38 patients, was irradiated with a pulsed GaAs diode laser, 904 nm, pulse width 200 nsec, pulse frequency 10,000 Hz, peak power of 20 W, average power 40 mW, spot size 150 cm2 in area, and an angle of divergence of 6°. The laser was applied in the point technique with a dose of 4 J/cm2 per point in the area of pain. Group B, consisting of 33 patients, was treated with sham irradiation with a deactivated laser system. Neither the patient nor the operator knew to which group each patient was randomly assigned. The use of analgesic drugs and physical therapy was excluded in both groups. Ten daily consecutive sessions were carried out once per day. Pain was evaluated through an analogue and visual scale at the beginning and at the end of the treatment. Laser treatment was considered effective when pain relief was more than 60%. A follow up was carried out over the following 6 months. The treatment was effective in 71% of patients in group A, and 36.4% of group B (p < 0.007). The pain disappeared completely in 44.7% of group A and 15.2% of group B (p < 0.01). During the six month follow-up period, in those patients in whom the response to the treatment was effective, the pain recurred in 34.8% of group A and in 70% of group B. No cutaneous, ophthalmologic or systemic side effects were observed. These results suggest that irradiation with GaAs laser at the doses used and techniques applied in this study, relieves chronic low back pain in older patients in a statistically significant percentage of the patients but without causing any adverse side effects.