Is low-level laser therapy useful as an adjunctive treatment for canine acral lick dermatitis? A randomized, double-blinded, sham-controlled study

BACKGROUND

Conventional therapy for canine acral lick dermatitis (ALD) consists of systemic antibiotics and anti-anxiety medications. Low-level laser therapy (LLLT) is a noninvasive therapy used to treat inflammatory and painful conditions.

HYPOTHESIS/OBJECTIVES

The primary objective was to determine whether LLLT with conventional therapy would be beneficial as an adjunct treatment for ALD. We hypothesized that LLLT and conventional therapy combined would result in a greater reduction in licking Visual Analog Score (LVAS) compared to conventional therapy alone. Secondary objectives were to assess change in lesion/ulcer size, thickness and hair growth.

ANIMALS

Thirteen dogs with a skin lesion consistent with ALD.

METHODS AND MATERIALS

Dogs were randomly assigned to two groups. All dogs received systemic antibiotics and trazodone. The treatment group (TG) received LLLT by laser (130 mW, 2 min) with blue and red light-emitting diodes (LEDs), while the control group (CG) had sham therapy (laser/LEDs off). Treatments were administered three times weekly for two weeks, then twice weekly for two weeks for a total of 10 visits. Descriptive statistics were performed (mean, median); primary and secondary objectives were assessed with nonparametric ANOVA (Kruskal-Wallis test), with significance set at P < 0.05.

RESULTS

Thirteen dogs (six CG, seven TG) were enrolled. There were no significant differences in median LVAS, lesion/ulcer size or thickness of the ALD lesion between TG and CG. There was a significantly greater increase (24%) in hair growth in TG (P = 0.0081) compared to CG.

CONCLUSIONS AND CLINICAL RELEVANCE

Treatment of ALD requires multimodal therapy. Although combining LLLT with conventional therapy did not result in a significantly greater reduction in LVAS, there was a significant increase in hair growth compared to conventional therapy alone.

Effects of Low-Level Laser Therapy Applied Before Treadmill Training on Recovery of Injured Skeletal Muscle in Wistar Rats

OBJECTIVE

The aim of this study was to analyze the effects of low-level laser therapy (LLLT) when associated with treadmill training on the recovery of skeletal muscle, during two periods of rest after muscle injury in rats.

BACKGROUND DATA

Because of photostimulation, LLLT has been presented as an alternative for accelerating the tissue healing process.

MATERIALS AND METHODS

Forty rats were divided into two groups (A and B) containing four subgroups each: GC (Control Group)-cryolesion untreated; EG (Exercise Group)-cryolesion treated with physical exercise; LG (Laser Group)-cryolesion treated with laser; ELG (Exercise and Laser Group)-cryolesion treated with laser and physical exercise. The right tibialis anterior (TA) of the middle belly was injured by a cooling iron bar (cryoinjury). Group A remained at rest for 3 days, whereas Group B remained at rest for 7 days. The laser parameters utilized were 780 nm with 15 mW average optical power and spot size of 0.04 cm(2) applied during 10 sec, leading to 0.152 J and 3.8 J/cm(2). Treadmill training with and without laser application was performed during 5 days, with each session lasting for 12 min at a velocity of 17 m/min. Subsequently, the TA muscle was removed for a histological and morphometric analysis.

RESULTS

The damaged area was significantly smaller for the ELG at both periods of rest, 3 and 7 days, respectively (4.4 ± 0.42% and 3.5 ± 0.14%, p < 0.05), when compared with the LG (18.6 ± 0.64% and 7.5 ± 0.13%), the EG (21 ± 0.26% and 8.7 ± 0.32%), and the CG (23.9 ± 0.37% and 21.4 ± 0.38%). In addition, the number of blood vessels were significantly higher for the ELG at both periods of rest, 3 and 7 days, respectively (71.2 ± 13.51 and 104.5 ± 11.78, p < 0.05), when compared with the LG (60.6 ± 11.25 and 93.5 ± 16.87), the EG (51.6 ± 7.3 and 93.8 ± 15.1) and the CG (34.4 ± 2.54 and 65.7 ± 14.1).

CONCLUSIONS

The LLLT applied before the physical exercise on the treadmill stimulated the angiogenesis and accelerated the process of muscle recovery.

Evaluation of the effects of pulsed wave LLLT on tibial diaphysis in two rat models of experimental osteoporosis, as examined by stereological and real-time PCR gene expression analyses

Osteoporosis (OP) and osteoporotic fracture are major public health issues for society; the burden for the affected individual is also high. Previous studies have shown that pulsed wave low-level laser therapy (PW LLLT) has osteogenic effects. This study intended to evaluate the impacts of PW LLLT on the cortical bone of osteoporotic rats' tibias in two experimental models, ovariectomized and dexamethasone-treated. We divided the rats into four ovariectomized induced OP (OVX-d) and four dexamethasone-treated (glucocorticoid-induced OP, GIOP) groups. A healthy (H) group of rats was considered for baseline evaluations. At 14 weeks following ovariectomy, we subdivided the OVX-d rats into the following groups: (i) control which had OP, (ii) OVX-d rats treated with alendronate (1 mg/kg), (iii) OVX-d rats treated with LLLT, and (iv) OVX-d rats treated with alendronate and PW LLLT. The remaining rats received dexamethasone over a 5-week period and were also subdivided into four groups: (i) control rats treated with intramuscular (i.m.) injections of distilled water (vehicle), (ii) rats treated with subcutaneous alendronate injections (1 mg/kg), (iii) laser-treated rats, and (iv) rats simultaneously treated with laser and alendronate. The rats received alendronate for 30 days and underwent PW LLLT (890 nm, 80 Hz, 0.972 J/cm(2)) three times per week during 8 weeks. Then, the right tibias were extracted and underwent a stereological analysis of histological parameters and real-time polymerase chain reaction (RT-PCR). A significant increase in cortical bone volume (mm(3)) existed in all study groups compared to the healthy rats. There were significant decreases in trabecular bone volume (mm(3)) in all study groups compared to the group of healthy rats. The control rats with OP and rats from the vehicle group showed significantly increased osteoclast numbers compared to most other groups. Alendronate significantly decreased osteoclast numbers in osteoporotic rats. Concurrent treatments (compounded by PW LLLT and alendronate) produce the same effect on osteoporotic bone.

Low-dose laser acupuncture for non-specific chronic low back pain: a double-blind randomised controlled trial

Objective

To determine if infrared laser acupuncture (LA) may have a specific effect in reducing pain and disability in treatment of chronic low back pain (LBP).

Methods

This was a double-blind sham laser controlled trial performed in general practices in Perth, Western Australia. The participants were 144 adults with chronic non-specific LBP. They were randomised to receive eight once-weekly treatments. Laser machines (20 mW, 840 nm diode, power density 0.1 W/cm²) stimulated points in three treatment groups: sham (0 joules/point), low dose (0.2 J/point) and high dose (0.8 joules/point). Participants were followed-up at 1 and 6 weeks, and 6 and 12 months post treatment. Primary outcomes were pain (Numerical Pain Rating Scale (NPRS)) and disability (Oswestry Disability Inventory (ODI)) at 6 weeks post treatment. Secondary outcomes included numerical rating scale for limitation of activity, global assessment of improvement, analgesic usage and adverse effects after treatment.

Results

The analysis showed no difference between sham and the laser groups at 6 weeks for pain or disability. There was a significant reduction in mean pain and disability in all groups at 6 weeks (p<0.005); NPRS: sham (−1.5 (95% CI −2.1 to −0.8)), low dose (−1.3 (−2.0 to −0.8)), high dose (−1.1 (−1.7 to −0.5)). ODI: sham (−4.0 (−7.1 to −1.0)), low dose (−4.1, (−6.7 to −1.5)), high dose (−2.6 (−5.7 to 0.5)). All secondary outcomes also showed clinical improvement over time but with no differences between groups.

Conclusions

LA using energy density range (0–4 J/cm²) for the treatment of chronic non-specific LBP resulted in clinical improvement unrelated to laser stimulation.

Trial registration

http://www.anzctr.org.au ACTRN12610000043033.

Electrophysiological effects of single point transcutaneous 650 and 808 nm laser irradiation of rat sciatic nerve: a study of relevance for low-level laser therapy and laser acupuncture

OBJECTIVE

The purpose of this study was to evaluate effects of transcutaneous 650 and 808 nm laser irradiation (LI) to a single point overlying rat sciatic nerve; a comparison to four point LI and relevance to the clinical application of low-level laser therapy (LLLT) and laser acupuncture (LA).

BACKGROUND DATA

Transcutaneous LI inhibits somatosensory and motor conduction when delivered to four points overlying sciatic nerve; however, effects of the same total energy delivered to a single point over the nerve, equating to laser acupuncture, are undefined.

METHODS

Transcutaneous 808 nm, 450 mW, (13.5 or 54 J) continuous wave (cw) mode or 650 nm, 35 mW, (1.1 or 4.4 J), cw LI or sham LI, was applied for 30 or 120 sec to a single point overlying the midpoint of rat sciatic nerve. Somatosensory evoked potentials (SSEPs) and compound muscle action potentials (CMAPs) were then recorded after 10 and 20 min, and after 24 and 48 h.

RESULTS

120 sec of 808 nm LI increased SSEP amplitudes only at 10 min, with no effect of 30 or 120 sec at other time points on SSEPs or on CMAPs. LI 650 nm for 30 or 120 sec did not alter SSEPs or CMAPs at any time point.

CONCLUSIONS

Localized transcutaneous 808 LI to a single point overlying sciatic nerve increases SSEP amplitudes when compared with delivery of the same total energy to four points, which causes decreased SSEP amplitudes and conduction block. Therefore, the area and duration of delivery are important, independent variables with implications for clinical delivery of both LLLT and LA.

Clinical effectiveness of low-level laser therapy as an adjunct to eccentric exercise for the treatment of Achilles' tendinopathy: a randomized controlled trial

OBJECTIVE

To investigate the effectiveness of low-level laser therapy (LLLT) as an adjunct to a program of eccentric exercises for the treatment of Achilles' tendinopathy.

DESIGN

Randomized controlled trial with evaluations at baseline and 4, 12, and 52 weeks.

SETTING

Primary care clinic.

PARTICIPANTS

Participants with midportion Achilles' tendinopathy were randomly assigned to 2 groups (LLLT n=20: mean age ± SD, 45.6±9.1y; placebo n=20: mean age ± SD, 46.5±6.4y). The 12-week evaluation was completed by 36 participants (90%), and 33 participants (82.5%) completed the 52-week evaluation.

INTERVENTION

Both groups of participants performed eccentric exercises over a 3-month period. In addition, they received either an active or placebo application of LLLT 3 times per week for the first 4 weeks; the dose was 3J per point.

MAIN OUTCOME MEASURES

The primary outcome was the Victorian Institute of Sport Assessment-Achilles' questionnaire (VISA-A) score at 12 weeks; secondary outcome was a visual analog scale for pain. Outcomes were measured at baseline and 4, 12, and 52 weeks.

RESULTS

Baseline characteristics exhibited no differences between groups. At the primary outcome point, there was no statistically significant difference in VISA-A scores between groups (P>.05). The difference in VISA-A scores at the 4-week point significantly favored the placebo group (F(1)=6.411, sum of squares 783.839; P=.016); all other outcome scores showed no significant difference between the groups at any time point. Observers were blinded to groupings.

CONCLUSIONS

The clinical effectiveness of adding LLLT to eccentric exercises for the treatment of Achilles' tendinopathy has not been demonstrated using the parameters in this study.

Laser acupuncture for chronic non-specific low back pain: a controlled clinical trial

OBJECTIVE

the primary aim was to determine if laser acupuncture (LA) is more effective than sham laser in reducing pain and disability in adults with chronic non-specific low back pain.

METHODS

the design was a double blind, two-group parallel randomised controlled trial. The active intervention was an 830 nm (infrared), 10 mW, Ga-Al-As laser diode laser for acupuncture and a sham control. The primary outcome measures were changes in pain (visual analogue scale) and disability (Oswestry Disability Index) at the end of 5-10 treatment sessions. Secondary outcomes were patient global assessment, psychological distress (Depression Anxiety Stress Scale) and subjective wellbeing (Personal Wellbeing Index). Follow up was performed at 6 weeks and 6 months after completion of treatment.

RESULTS

100 participants were enrolled and treated in a general practice setting. Per protocol analysis of the primary outcome measures using ANOVA suggested that although there was a significant overall improvement in pain and disability after the course of treatments (p<0.01), there was no significant difference between the intervention and control group in both the primary and most secondary outcome measures.

CONCLUSION

this study did not show a specific effect for LA using infrared laser at 0.2 Joules per point for chronic low back pain. The overall intervention appeared effective because of placebo and other factors. As there was some concern about baseline inequality between the groups further research using tighter inclusion criteria should attempt to replicate the result and examine if a dose response may exist.

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

BACKGROUND AND OBJECTIVES

Low-level laser therapy (LLLT) is widely used in the treatment of musculoskeletal pain. However, there is controversy over its true efficacy. We aimed to determine the efficacy of LLLT in the treatment of neck pain through systematically reviewing the literature.

STUDY DESIGN/MATERIALS AND METHODS

A search of computerized bibliographic databases covering medicine, physiotherapy, allied health, complementary medicine, and biological sciences was undertaken undertaken from date of inception until February 2004 for randomized controlled trials of LLLT for neck pain. A comprehensive list of search terms was applied and explicit inclusion criteria were developed a priori. Twenty studies were identified, five of which met the inclusion criteria.

RESULTS

Significant positive effects were reported in four of five trials in which infrared wavelengths (lambda = 780, 810-830, 904, 1,064 nm) were used. Heterogeneity in outcome measures, results reporting, doses, and laser parameters precluded formal meta-analysis. Effect sizes could be calculated for only two of the studies.

CONCLUSIONS

This review provides limited evidence from one RCT for the use of infrared laser for the treatment of acute neck pain (n = 71) and chronic neck pain from four RCTs (n = 202). Larger studies are required to confirm the positive findings and determine the most effective laser parameters, sites and modes of application.