Effects of diode laser therapy on blood flow in axial pattern flaps in the rat model

Expediting the reversal of inferior alveolar nerve block anesthesia in children with photobiomodulation therapy

In pediatric dentistry, complications arising from extended soft tissue anesthesia can negatively impact patient comfort and trust in dental care. This study evaluates the clinical efficacy of diode laser-based photobiomodulation therapy (PBMT) in expediting the resolution of anesthesia in children aged 6-9 receiving inferior alveolar nerve block (IANB) injections. In this split-mouth double-blind randomized clinical trial, 36 pediatric subjects aged 6-9, requiring pulpotomy procedures on both sides of the mandible, received IANBs (single cartridge of 2% lidocaine/1:100,000 epinephrine). PBMT and sham laser were alternately applied to each side of the mandible, in two separate sessions, with the envelope method determining treatment allocation and intervention side on the first treatment day. During the laser session, laser (808 nm, 250 mW, 23s continuous, 0.5 cm², 11.5 J/cm², direct contact) irradiated two points at the injection site, five intra-oral and five extra-oral points along the infra-alveolar nerve's pathway. Soft tissue anesthesia reversal was quantified through tactile assessment. Soft tissue trauma was also assessed by the researcher and reported by parents 24 h post-dental visit. All data were analyzed using IBM SPSS Statistics v25.0 via Paired T-test, two-way repeated measures ANOVA, and McNemar's test. The laser group exhibited a mean lip anesthesia duration of 122.78 ± 2.26 min, while the sham laser group experienced 134.44 ± 21.8 min, indicating an 11.66-minute reduction in anesthesia duration for the laser group. (P < 0.001) Soft tissue trauma occurred in two sham laser group patients and one laser group patient, with no significant difference. (P = 1) The findings indicate that employing laser with defined parameters can reduce the length of IANB-induced anesthesia.

Photobiomodulation in promoting increased Skin Flap Viability: a systematic review of animal studies

Necrosis is common in skin flap surgeries. Photobiomodulation, a noninvasive and effective technique, holds the potential to enhance microcirculation and neovascularization. As such, it has emerged as a viable approach for mitigating the occurrence of skin flap necrosis. The aim of this systematic review was to examine the scientific literature considering the use of photobiomodulation to increase skin-flap viability. The preferred reporting items for systematic reviews and meta-analyses (PRISMA), was used to conducted systematic literature search in the databases PubMed, SCOPUS, Elsevier and, Scielo on June 2023. Included studies investigated skin-flap necrosis employing PBMT irradiation as a treatment and, at least one quantitative measure of skin-flap necrosis in any animal model. Twenty-five studies were selected from 54 original articles that addressed PBMT with low-level laser (LLL) or light-emitting diode (LED) in agreement with the qualifying requirements. Laser parameters varied markedly across studies. In the selected studies, the low-level laser in the visible red spectrum was the most frequently utilized PBMT, although the LED PBMT showed a similar improvement in skin-flap necrosis. Ninety percent of the studies assessing the outcomes of the effects of PBMT reported smaller areas of necrosis in skin flap. Studies have consistently demonstrated the ability of PBMT to improve skin flap viability in animal models. Evidence suggests that PBMT, through enhancing angiogenesis, vascular density, mast cells, and VEGF, is an effective therapy for decrease necrotic tissue in skin flap surgery.

Comparative evaluation of photobiomodulation therapy at 660 and 810 nm wavelengths on the soft tissue local anesthesia reversal in pediatric dentistry: an in-vivo study

BACKGROUND

Local anesthesia has been reliably used to control pain during dental procedures and is important in pediatric dentistry. However, children occasionally complain of prolonged numbness after dental treatment, leading to several problems. Studies conducted to reverse the effect of local anesthesia using phentolamine mesylate and photobiomodulation therapy (PBM) are encouraging but limited. PBM is a type of light therapy that utilizes visible and near-infrared non-ionizing electromagnetic spectral light sources. Hence, this study used this modality to compare the reversal of local anesthesia at two different wavelengths. This study compared the effect of PBM at 660 and 810 nm wavelengths on the reversal of soft tissue local anesthesia using a diode LASER in pediatric dentistry.

METHOD

Informed consent and assent were obtained, and the participants were then divided randomly into three groups of 20 children each: control group-without LASER irradiation, LASER irradiation at 660 nm, and LASER irradiation at 810 nm. Sixty children aged 4-8 years with deciduous mandibular molars indicated for pulp therapy were administered an inferior alveolar nerve block. After 45 min of injection, a duration that was similar to the approximate duration of treatment, they were exposed to 660- and 810-nm LASER irradiation according to their groups until reversal of local anesthesia was achieved. The control group did not undergo LASER irradiation. The reversal of the soft tissue local anesthetic effect was evaluated using palpation and pin prick tests every 15 min, and the LASER irradiation cycle continued until reversal of the soft tissue local anesthesia was achieved.

RESULTS

A significant reduction of 55.5 min (27.6%) in the mean soft tissue local anesthesia reversal time was observed after the application of 810 nm wavelength PBM and 69 min (34.7%) after 660 nm wavelength LASER irradiation.

CONCLUSION

PBM with a 660 nm wavelength was more effective in reducing the mean soft tissue local anesthesia reversal duration, and thus can be used as a reversal agent for soft tissue local anesthesia in pediatric dentistry.

Effects of low level laser therapy on injection pain and anesthesia efficacy during local anesthesia in children: A randomized clinical trial

BACKGROUND

The use of low level laser therapy (LLLT) to reduce injection pain associated with dental local anesthesia is reported in a limited number of studies in adults, but research on the effects of LLLT in children is needed.

AIM

This study aimed to evaluate the effects of topical anesthesia + LLLT on injection pain, anesthesia efficacy, and duration in local anesthesia of children who are undergoing pulpotomy treatment.

DESIGN

The study was conducted as a randomized, controlled-crossover, double-blind clinical trial with 60 children aged 6-9 years. Before local infiltration anesthesia was administered, only topical anesthesia was applied in one side (control group/CG), and topical anesthesia plus LLLT (a diode laser: 810 nm; continuous mode; 0.3W; 20 s; 69 J/cm² ) was applied in the contralateral side (LG) as pre-anesthesia. The injection pain and anesthesia efficacy were evaluated subjectively and objectively using the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability (FLACC) scale respectively. Data were analyzed for statistical significance (p < .05).

RESULTS

The "no pain" and "severe pain" rates in the PRS were 41.7% and 3.3% for the LG and 21.7% and 11.7% for the CG, respectively, during injection. Similarly, in the FLACC data, the number of "no pain" responses was higher for the LG than the CG (40%, 33.3%) and no "severe pain" rate was observed in both groups. The only statistically significant difference found for the PRS was p < .05. The median pain score was "0" for the LG and the CG in the FLACC data for the evaluation of anesthesia efficacy, and there was no statistically significant difference between the groups in terms of pain and anesthesia duration (p > .05). Also, most of the children preferred injection with topical anesthesia + LLLT (66.7%).

CONCLUSIONS

It has been determined that the application of topical anesthesia + LLLT with an 810-nm diode laser before local infiltration anesthesia reduced injection pain and did not have an effect on anesthesia efficacy and duration in children.

Photobiomodulation effect in tumoral necrosis factor-alpha(TNF-α) on the viability of random skin flap in rats

The aim of this study was to investigate the effect of red laser (660 nm) photobiomodulation (PBM) with different energies on tumor necrosis factor-alpha(TNF-α) expression for random skin flap viability in rats. Twenty-four Wistar rats were divided into three groups: sham group (SG), PBM laser group with an energy dose of 0.29 J (0.29G), and PBM laser group with an energy dose of 7.30 J (7.30G). A cranially based dorsal skin flap measuring 10 × 4 cm was raised and a plastic barrier was placed between the flap and its bed. PBM was applied in 3 timepoints: in the immediate postoperative period, in the 1^st and in the 2^nd postoperative days; the animals were euthanized on the 7^th postoperative day. The assessments included: TNF-α expression of 3 different flap areas (proximal, medial and distal), by immunohistochemistry; percentage of skin flap necrosis area, by the paper template method. The statistical analysis was performed through the Kruskal-Wallis and Mann-Whitney tests, the level of significance adopted was 5% (p < 0.05). TNF-α expression was significantly lower for 7.30G in the proximal area, reduced for SG in the medial point, and larger for 7.30G in the distal area. The percentage of flap necrosis area was significantly reduced for 7.30G. Higher energy doses are more efficacious than lower energy doses for modulating TNF-α expression. PBM with an energy dose of 7.30 J was effective in reducing the expression of TNF-α and increase skin flap viability.

Comparison of the Effect of High-Intensity Laser Therapy (HILT) on Skin Surface Temperature and Vein Diameter in Pigmented and Non-Pigmented Skin in Healthy Racehorses

Simple Summary

High-intensity laser therapy (HILT) is used in the treatment of horses, but little is known about the differences in the impact of HILT performed on pigmented and non-pigmented skin. The aim of this study was to assess differences in the influence of HILT on skin surface temperature and vein diameter in a group of healthy racehorses with pigmented and non-pigmented skin in the treatment area. The hypothesis was that HILT would cause a greater increase in skin surface temperature and vein diameter in horses with pigmented skin compared to non-pigmented skin. Ten Thoroughbreds with pigmented skin and ten Thoroughbreds with non-pigmented skin in the treatment area received HILT. Changes in the vein diameter and skin surface temperature of the irradiated area were measured before and after HILT. The HILT treatment caused an increase in the pigmented skin surface temperature and a decrease in the non-pigmented skin surface temperature, while the vein diameter increased in both groups. In conclusion, melanin content in the epidermis plays an important role in light energy absorption and photothermal effects. Determining the physiological and clinical effects of HILT performed on pigmented and non-pigmented skin will help clinicians choose appropriate HILT parameters.

Abstract

The aim of the study was to assess differences in the influence of high-intensity laser therapy (HILT) on the skin surface temperature and vein diameter of the lateral fetlock joint region in a group of racehorses with pigmented and non-pigmented skin in the treatment area. Twenty Thoroughbreds were divided into two equal groups: pigmented and non-pigmented skin groups. Each horse received the same HILT treatment. Just before and immediately after HILT, thermographic examination was performed to measure the skin surface temperature and ultrasonographic examination assessed the lateral digital palmar vein diameter. After HILT, the pigmented skin surface temperature increased, while the non-pigmented skin surface temperature decreased, and the difference between both groups was significant (p < 0.001). The vein diameter increased after HILT in horses with pigmented and non-pigmented skin, but the difference between both groups was not significant (p = 0.14). In conclusion, melanin content in the epidermis plays an important role in light energy absorption and photothermal effects. The vein diameter changes after HILT application indicated that the increase in vessel diameter may partly depend on photothermal mechanisms occurring in irradiated tissue. Further research is necessary to describe the physiological and clinical effects of HILT performed on pigmented and non-pigmented skin.

Low-level laser therapy for the treatment of early stage cutaneous leishmaniasis: A pilot study

Low-Level Laser Therapy (LLLT) has been investigated for the treatment of various dermatological disorders. Here, we investigate the efficacy of LLLT for the treatment of cutaneous leishmaniasis (CL). This study comprised of 53 patients (total 123 lesions) with a confirmed diagnosis of CL via positive smear of LD-bodies. The CL lesions were classified in Grade I (ie, papule of size ≤1 cm) to Grade V (ie, vesicle formation, ulceration, and superadded infection of size >4 cm). All the patients were divided into group 1 with low grade (ie, Grade I and II) CL lesions and group 2 with high-grade disease (ie, Grade III-V). Red laser light (wavelength = 635 nm) was used for the lesion irradiation, with a light dose of 75 J/cm2 and at a low power of 300 mW. The treatment was divided into four sessions, one session per week. Disease assessment at 10 months follow-up revealed complete response in 91% and partial response in 9% patients of group 1, while no response was observed in patients of group 2. LLLT offers a promising treatment modality for patients presenting with early-stage (ie, Grade I and II) CL lesions.

Assessment of Vein Diameter and Body Surface Temperature after High-Intensity Laser Therapy (HILT) on the Tarsal Joint in Healthy Horses

The aim of the study was to assess the influence of high-intensity laser therapy (HILT) on vein diameter and on body surface temperature changes in the tarsal joint area in a group of clinically healthy racehorses. The hypothesis of the study was that HILT increases vein diameter and body surface temperature in healthy tissue. The study involved 16 Thoroughbreds being subjected to ultrasonographic examination to assess changes of diameter of the cranial branch of the medial saphenous vein and thermographic examination to indicate temperature change of the dorsal surface of the tarsal joint, just before and immediately after HILT treatment. Vein diameter and mean surface temperature of the tarsal joint significantly increased after HILT treatment. In addition, the study was the first to describe the photothermal effect of HILT in healthy horses. More studies are necessary to specify the parameters of the procedure, that is, wavelength, energy density, or time of the procedure, depending on the patient's individual characteristics and type of tissue.

Photobiomodulation effect on local hemoglobin concentration assessed by near-infrared spectroscopy in humans

Exposure of biological tissue to photobiomodulation therapy (PBMT) seems to increase the oxygen availability and mitochondrial electrochemical activity. With the advancement of new technologies, such as near-infrared spectroscopy (NIRS), information can be obtained about the balance between oxygen utilization and delivery by assessing local oxy- ([O₂Hb]) and deoxy-myohemoglobin ([HHb]) concentrations, both measured in micromolars (μM). Consequently, NIRS can be used to study ("in vivo") PBMT effects on the oxidative system, including oxygen availability. Thus, the main objective of the present study was to use NIRS to investigate the acute effects of PBMT by light-emitting diode (LED) on the oxygen delivery and utilization in humans. Twelve healthy young participants were treated with a LED device (850 nm, 50 mW, 2 J) and placebo applied over the proximal third of the flexor carpi ulnaris muscle of the left or right forearm selected in a random order. The LED was applied in direct contact with skin and the device was switched on for 40 s in 4 different interventions (I₁, I₂, I₃ and I₄) with a 3-min interval between interventions. The placebo condition was considered as the period before the first PBMT. The NIRS device was used to evaluate the relative changes in [O₂Hb] and [HHb] before and after placebo and interventions. We found that PBMT statistically increased the [O₂Hb] in 0.39 μM. These results demonstrate the potential of PBMT to increase oxygen availability.

Assessment of photobiomodulation therapy by an 8l0-nm diode laser on the reversal of soft tissue local anesthesia in pediatric dentistry: a preliminary randomized clinical trial

During the injection of local anesthesia in pediatric dental procedures, from the injection time until the elimination of tissue anesthesia, inevitable problems were reported. According to the encouraging results of previous studies addressing the positive effects of laser therapy on increasing the microcirculation, we aimed to investigate the clinical effect of photobiomodulation therapy on the reversal of soft tissue anesthesia in children. Using a split-mouth design, 34 children aged 4 to 8 years old, candidate for receiving local infiltration injection at both right and left side in mandible, were enrolled in the study. The mandibular right and left quadrants were randomly assigned to groups of laser or sham laser: in laser side, patients received 810-nm laser irradiation, and in the sham laser group, the patients had the laser in off mode at 45 min after injection with an interval of 7-10 days between two sessions of each quadrant treatments. The degree of anesthesia was evaluated using the palpation technique alternately every 15 min. Data were analyzed using paired sample t test and multiple linear regression test. The mean duration of anesthesia expressed in minutes was equal to 145.15 ± 23.27 and 188.82 ± 12.31 for the laser group and sham laser group, respectively. There was a significant difference in duration of anesthesia between two groups (P < 0.001). Considering the results and limitations of the present study, photobiomodulation therapy by 810-nm diode laser can be proposed as a non-invasive method in order to reduce the duration of anesthesia in pediatric patients.

Effect of 810 nm Near-Infrared Laser on Revascularization of Ischemic Flaps in Rats

OBJECTIVE

To investigate the effect of 810 nm near-infrared (NIR) laser on the revascularization of ischemic flaps.

BACKGROUND

It has long been proved that photobiomodulation therapy (PBMT) improves the blood supply of flaps. NIR laser improves the treatment of hypodermis-located lesions and of flap survival, but basic research on the use of 810 nm NIR laser for ischemic flap revascularization is still lacking.

MATERIALS AND METHODS

We prepared two symmetrical long random-pattern flaps on the backs of 60 rats. Each flap was 6 cm long, 1 cm wide, and 1 cm to the middle line. The flaps were divided into an irradiated flap group and an internal control group. The irradiated flaps underwent postoperative 810 nm laser therapy with the energy density of 11.30 J/cm² daily. The control flaps were covered by stainless steel to avoid laser irradiation. We observed the viability of the flaps. The flaps underwent Hematoxylin and Eosin (H&E) staining for the observation of histomorphology, immunohistochemical staining of factor VIII for the capillary count, α-smooth muscle actin for the small arterial count, and vascular endothelial growth factor for the integrated optical density (OD) of the positive stained color.

RESULTS

The irradiated flaps showed significantly better flap survival than the control flaps. H&E staining showed that the irradiated flaps had clear tissue structure and little inflammatory cell infiltration. The control flaps demonstrated comparatively worse results. Vascular endothelial growth factor staining showed that the difference in integrated OD between the irradiated flaps and the control flaps was not statistically significant. α-smooth muscle actin and factor VIII staining showed significantly greater numbers of arterioles and capillaries in the irradiated flaps than the control flaps after 4 days of irradiation.

CONCLUSIONS

PBMT with 810 nm NIR laser could enhance ischemic flap revascularization and increase flap viability.

Comparison of two different laser photobiomodulation protocols on the viability of random skin flap in rats

To identify the best low level laser photobiomodulation application site at the same irradiation time to increase the viability of the skin flap in rats. Eighteen male rats (Rattus norvegicus: var. Albinus, Rodentia Mammalia) were randomly distributed into three groups (n = 6). Group I (GI) was submitted to simulated laser photobiomodulation; group II (GII) was submitted to laser photobiomodulation at three points in the flap cranial base, and group III (GIII) was submitted to laser photobiomodulation at 12 points distributed along the flap. All groups were irradiated with an Indium, Galium, Aluminum, and Phosphorus diode laser (InGaAlP), 660 nm, with 50 mW power, irradiated for a total time of 240 s in continuous emission mode. The treatment started immediately after performing the cranial base random skin flap (10 × 4 cm² dimension) and reapplied every 24 h, with a total of five applications. The animals were euthanized after the evaluation of the percentage of necrosis area, and the material was collected for histological analysis on the seventh postoperative day. GII animals presented a statistically significant decrease for the necrosis area when compared to the other groups, and a statistically significant increase in the quantification of collagen when compared to the control. We did not observe a statistical difference between the TGFβ and FGF expression in the different groups evaluated. The application of laser photobiomodulation at three points of the flap cranial base was more effective than at 12 points regarding the reduction of necrosis area.

Photobiomodulation Therapy in Veterinary Medicine: A Review

Laser therapy, or photobiomodulation, has rapidly grown in popularity in human and veterinary medicine. With a number of proposed indications and broad, sometimes anecdotal, use in practice, research interest has expanded aimed at providing scientific support. Recent studies have shown that laser therapy alters the inflammatory and immune response as well as promotes healing for a variety of tissue types. This review will cover the history of the modality, basic principles, proposed mechanisms of action, evidence-based clinical indications, and will guide the practitioner through its application in practice.

Increased visceral tissue perfusion with heated, humidified carbon dioxide insufflation during open abdominal surgery in a rodent model

Tissue perfusion during surgery is important in reducing surgical site infections and promoting healing. This study aimed to determine if insufflation of the open abdomen with heated, humidified (HH) carbon dioxide (CO2) increased visceral tissue perfusion and core body temperature during open abdominal surgery in a rodent model. Using two different rodent models of open abdominal surgery, visceral perfusion and core temperature were measured. Visceral perfusion was investigated using a repeated measures crossover experiment with rodents receiving the same sequence of two alternating treatments: exposure to ambient air (no insufflation) and insufflation with HH CO2. Core body temperature was measured using an independent experimental design with three treatment groups: ambient air, HH CO2 and cold, dry (CD) CO2. Visceral perfusion was measured by laser speckle contrast analysis (LASCA) and core body temperature was measured with a rectal thermometer. Insufflation with HH CO2 into a rodent open abdominal cavity significantly increased visceral tissue perfusion (2.4 perfusion units (PU)/min (95% CI 1.23-3.58); p<0.0001) compared with ambient air, which significantly reduced visceral blood flow (-5.20 PU/min (95% CI -6.83- -3.58); p<0.0001). Insufflation of HH CO2 into the open abdominal cavity significantly increased core body temperature (+1.15 ± 0.14°C) compared with open cavities exposed to ambient air (-0.65 ± 0.52°C; p = 0.037), or cavities insufflated with CD CO2 (-0.73 ± 0.33°C; p = 0.006). Abdominal visceral temperatures also increased with HH CO2 insufflation compared with ambient air or CD CO2, as shown by infrared thermography. This study reports for the first time the use of LASCA to measure visceral perfusion in open abdominal surgery and shows that insufflation of open abdominal cavities with HH CO2 significantly increases visceral tissue perfusion and core body temperature.

Effects of Near-Infrared Light on Cerebral Bioenergetics Measured with Phosphorus Magnetic Resonance Spectroscopy

OBJECTIVE

Cerebral photobiomodulation (PBM) improves mood and cognition. Cerebral metabolic enhancement is a mechanism proposed to underlie PBM effects. No PBM studies to date have applied phosphorus magnetic resonance spectroscopy (³¹P MRS), which can be used to assess metabolic intermediates such as phosphocreatine (PCr) and adenosine triphosphate, the latter of which is elevated by PBM. Accordingly, we used 9.4 Tesla ³¹P MRS to characterize effects of single and repeat cerebral PBM treatments on metabolism. PBM was delivered to healthy adult beagles in the form of transcranial laser treatment (TLT) at a wavelength of 808 nm, which passes safely through the skull and activates cytochrome C oxidase, a mitochondrial respiratory chain enzyme.

METHODS

Isoflurane-anesthetized subjects (n = 4) underwent a baseline ³¹P MRS scan followed by TLT applied sequentially for 2 min each to anterior and posterior cranium midline locations, to irradiate the dorsal cortex. Subjects then underwent ³¹P MRS scans for 2 h to assess acute TLT effects. After 2 weeks of repeat TLT (3 times/week), subjects were scanned again with ³¹P MRS to characterize effects of repeat TLT.

RESULTS

TLT did not induce acute ³¹P MRS changes over the course of 2 h in either scan session. However, after repeat TLT, the baseline PCr/β-nucleoside triphosphate ratio was higher than the scan 1 baseline (p < 0.0001), an effect attributable to increased PCr level (p < 0.0001).

CONCLUSIONS

Our findings are consistent with reports that bioenergetic effects of PBM can take several hours to evolve. Thus, in vivo ³¹P MRS may be useful for characterizing bioenergetic effects of PBM in brain and other tissues.

Laser photobiomodulation (830 and 660 nm) in mast cells, VEGF, FGF, and CD34 of the musculocutaneous flap in rats submitted to nicotine

The aim of this study was to investigate the effect of laser photobiomodulation (PBM) on the viability of the transverse rectus abdominis musculocutaneous (TRAM) flap in rats subjected to the action of nicotine. We evaluated 60 albino Wistar rats, divided into six groups of ten animals. Group 1 (saline) underwent the surgical technique to obtain a TRAM flap; group 2 (laser 830 nm) underwent the surgical technique and was irradiated with a laser 830 nm; group 3 (laser 660 nm) underwent the surgical technique and was irradiated with a laser 660 nm; group 4 was treated with nicotine subcutaneously (2 mg/kg/2×/day/4 weeks) and underwent surgery; group 5 (nicotine + laser 830 nm) was exposed to nicotine, underwent the surgical technique, and was irradiated with a laser 830 nm; group 6 (nicotine + laser 660 nm) was exposed to nicotine, underwent the surgical technique, and was irradiated with a laser 660 nm. The application of PBM occurred immediately after surgery and on the two following days. The percentage of necrosis was assessed using the AxioVision® software. The number of mast cells (toluidine blue staining) was evaluated, and immunohistochemistry was performed to detect vascular endothelial growth factor expression (anti-VEGF-A), fibroblasts (anti-basic FGF), and neoformed vessels (anti-CD34). PBM with a wavelength of 830 nm increased the viability of the TRAM flap, with a smaller area of necrosis, increased number of mast cells, and higher expression of VEGF and CD34. PBM increases the viability of musculocutaneous flaps treated with to nicotine.

Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model

Background

Although several studies have demonstrated the effects of low-level laser therapy (LLLT) on skin flap viability, the role of higher doses has been poorly investigated.

Objective

To investigate the inhibitory effect of the LLLT (λ=670 nm) on the viability of random skin flaps in a rat model using an irradiation energy of 2.79 J at each point.

Methods

Sixteen Wistar rats were randomly assigned into two groups: sham laser irradiation (n=8); and active laser irradiation (n=8). Animals in the active laser irradiation group were irradiated with a 670 nm diode laser with an energy of 2.79 J/point, a power output 30 mW, a beam area of 0.028 cm2, an energy density of 100 J/cm2, an irradiance of 1.07 W/cm2 for 93 s/point. Irradiation was performed in 12 points in the cranial skin flap portion. The total energy irradiated on the tissue was 33.48 J. The necrotic area was evaluated on postoperative day 7.

Results

The sham laser irradiation group presented a mean (± SD) necrotic area of 47.96±3.81%, whereas the active laser irradiation group presented 62.24±7.28%. There was a significant difference in skin-flap necrosis areas between groups (P=0.0002).

Conclusion

LLLT (λ=670 nm) increased the necrotic area of random skin flaps in rats when irradiated with an energy of 2.79 J (100 J/cm2).

Is light-emitting diode phototherapy (LED-LLLT) really effective?

BACKGROUND

Low level light therapy (LLLT) has attracted attention in many clinical fields with a new generation of light-emitting diodes (LEDs) which can irradiate large targets. To pain control, the first main application of LLLT, have been added LED-LLLT in the accelerated healing of wounds, both traumatic and iatrogenic, inflammatory acne and the patient-driven application of skin rejuvenation. Rationale and Applications: The rationale behind LED-LLLT is underpinned by the reported efficacy of LED-LLLT at a cellular and subcellular level, particularly for the 633 nm and 830 nm wavelengths, and evidence for this is presented. Improved blood flow and neovascularization are associated with 830 nm. A large variety of cytokines, chemokines and macromolecules can be induced by LED phototherapy. Among the clinical applications, non-healing wounds can be healed through restoring the collagenesis/collagenase imbalance in such examples, and 'normal' wounds heal faster and better. Pain, including postoperative pain, postoperative edema and many types of inflammation can be significantly reduced. Experimental and clinical evidence: Some personal examples of evidence are offered by the first author, including controlled animal models demonstrating the systemic effect of 830 nm LED-LLLT on wound healing and on induced inflammation. Human patients are presented to illustrate the efficacy of LED phototherapy on treatment-resistant inflammatory disorders.

CONCLUSIONS

Provided an LED phototherapy system has the correct wavelength for the target cells, delivers an appropriate power density and an adequate energy density, then it will be at least partly, if not significantly, effective. The use of LED-LLLT as an adjunct to conventional surgical or nonsurgical indications is an even more exciting prospect. LED-LLLT is here to stay.

Personal Overview of the Application of LLLT in Severely Infertile Japanese Females

BACKGROUND AND AIMS

The rapidly graying population in Japan is being compounded by the rapidly-dropping birth rate. The latter is mostly due to the later ages at which women are giving birth as the marriage age has also been increasing. Giving birth at a later stage is associated with problems for both mother and child, but for older would-be mothers the greatest problem is infertility, sometimes severe. The present article will show how the application of low level laser therapy (LLLT) is a potentially effective treatment for severe infertility.

SUBJECTS AND METHODS

Seventy-four females (average age 39.28 yr) with severe infertility in whom assisted reproductive technology (ART) had been unsuccessful (average of 9.13 yr) participated in the first part of a study from October 1996 - April 2000. LLLT was applied (830 nm, CW, GaAlAs 60 mW diode LLLT) in Ohshiro's proximal priority technique (average 21.08 sessions) with or without other ART approaches. Based on successful outcomes, the study was then extended to March 2012, amassing a final total of 701 patients.

RESULTS

Pregnancy was achieved in the first part of the trial in 16 patients (21.7% of 74) of whom 11 (68%) achieved successful live delivery. In the extended trial, pregnancy was achieved in 156 (22.3% of 701) with 79 live deliveries (50.1%).

CONCLUSIONS

The use of 830 nm LLLT in the proximal priority technique at the parameters used in the present study, on its own or as an adjunct to other techniques, resulted in successful induction of pregnancy in just over 21% of severely infertile females, with a substantial number of these achieving live births. No adverse events were noted in any patient. LLLT is a pain-free and sideeffect free modality which could give hope to the increasing numbers of older females with infertility in Japan and potentially worldwide. Multinational studies are warranted.

The effects of different doses of 670 nm diode laser on skin flap survival in rats

PURPOSE

To investigate the effects of different low-level laser therapy (LLLT) doses on random skin flap rats.

METHODS

Forty Wistar rats were randomly divided in four groups. The control group (CG) was not irradiated. The experimental groups were irradiated with a diode laser 670 nm with different energies per point: group 2 (G2) with 0.06 J; group 3 (G3) 0.15 J and group 4 (G4) 0.57 J. The three groups were irradiated in 12 equally distributed points in the cranial skin flap portion. They were submitted to the irradiation during the immediate, first and second postoperative days. The necrosis area was evaluated in the seventh postoperative day.

RESULTS

The CG shows 49.35% of necrosis area in the skin flap; G2, 39.14%; G3, 47.01% and G4, 29.17% respectively. There was a significantly difference when G4 was compared with CG`s skin flap necrosis area.

CONCLUSION

The low-level laser therapy diode 670 nm with 0.57 J energy per point increases the survival in randomic skin flap rats.

Review of laser speckle-based analysis in medical imaging

Speckle pattern forms when a rough object is illuminated with coherent light (laser) and the backscattered radiation is imaged on a screen. The pattern changes over time due to movement in the object. Such time-integrate speckle pattern can be statistically analyzed to reveal the flow profile. For higher velocity the speckle contrast gets reduced. This theory can be utilized for tissue perfusion in capillaries of human skin tissue and cerebral blood flow mapping in rodents. Early, the technique was suffered from low resolution and computational intricacies for real-time monitoring purpose. However, modern engineering has made it feasible for real-time monitoring in microcirculation imaging with improved resolution. This review illustrates several modifications over classical technique done by many researchers. Recent advances in speckle contrast methods gain major interest, leading towards practical implementation of this technique. The review also brings out the scopes of laser speckle-based analysis in various medical applications.

The systemic effect of 830-nm LED phototherapy on the wound healing of burn injuries: A controlled study in mouse and rat models

BACKGROUND

The present controlled study assessed the systemic effect of 830-nm LED phototherapy in rodent models.

MATERIALS AND METHODS

Two HR-1 hairless mice and 3 HWY/Slc hairless rats were divided into two groups: the treatment group (Tx Group, one mouse, two rats) and the control group (Con Group, one mouse, one rat). All animals received an identical 12 mm × 12 mm control burn over three sites on the dorsum with a fractional ablative CO(2) laser. Wounds were protected with a film-type dressing. The abdomen of the Tx Group subjects was irradiated with an 830-nm LED array immediately post CO(2) treatment and then at 1, 5 and 6 days post laser irradiation. Wound healing was assessed macroscopically from the clinical photography.

RESULTS

At the 2-day post-laser assessment, the healing process in the wounds in the Tx Group was already apparent compared with the Con Group. At the final evaluation (post-burn day 7), no site on the Con Group (six wounds) showed 100% healing, recovery was over 70% in four and lower than 50% in two sites. Of the nine Tx Group sites, 100% recovery was seen in three sites, over 70% in five sites and one wound was exacerbated through trauma.

CONCLUSIONS

LED phototherapy on the abdomen produced faster wound healing of the uniform burn wounds than in animals with the same burn wounds that did not receive LED phototherapy, strongly suggesting the systemic effect of phototherapy.

Low-level laser irradiation, cyclooxygenase-2 (COX-2) expression and necrosis of random skin flaps in rats

Skin flaps are still a matter of concern among surgeons, as failures can occur leading to flap necrosis. However, low-level laser irradiation has been reported as an effective tool to improve the viability of ischemic flaps, yet its mechanisms of action remain unclear. We investigated the effect of low-level laser irradiation on the viability of random skin flaps in rats and determined COX-2 expression in the flap pedicle. The study animals comprised 24 EPM-1 Wistar rats which were randomly allocated into three equal groups. A cranially based dorsal random skin flap measuring 10 × 4 cm was created in all the animals. In one group, laser irradiation was simulated (sham group), and in the other two groups the animals were irradiated at 12 points with 0.29 J at 20 mW (energy density 10.36 J/cm(2), irradiance 0.71 W/cm(2)), or with 7.3 J at 100 mW (energy density 260.7 J/cm(2), irradiance 3.57 W/cm(2)). These procedures were applied to the cranial half of the flap immediately after surgery and were repeated on days 2 and 5 after surgery. The percentage necrotic area was determined on day 7 after surgery by the paper template method. The immunohistochemical expression of COX-2 in the samples was given scores from 0 to 3. The necrotic area was smaller in group irradiated at 7.3 J compared to sham-treated group and to the group irradiated at 0.29 J (P < 0.05); there was no difference between the sham-treated group and group irradiated at 0.29 J. COX-2 expression was lower in the group irradiated at 7.3 J than in the sham-treated group and the group irradiated at 0.29 J (P < 0.001). Low-level laser therapy was effective in decreasing random skin flap necrosis in rats using a laser energy of 7.30 J per point. Laser irradiation also decreased the expression of COX-2 in the flap pedicle.

Time domain algorithm for accelerated determination of the first order moment of photo current fluctuations in high speed laser Doppler perfusion imaging

Advances in optical array sensor technology allow for the real time acquisition of dynamic laser speckle patterns generated by tissue perfusion, which, in principle, allows for real time laser Doppler perfusion imaging (LDPI). Exploitation of these developments is enhanced with the introduction of faster algorithms to transform photo currents into perfusion estimates using the first moment of the power spectrum. A time domain (TD) algorithm is presented for determining the first-order spectral moment. Experiments are performed to compare this algorithm with the widely used Fast Fourier Transform (FFT). This study shows that the TD-algorithm is twice as fast as the FFT-algorithm without loss of accuracy. Compared to FFT, the TD-algorithm is efficient in terms of processor time, memory usage and data transport.

Laser 830nm na viabilidade do retalho cutâneo de ratos submetidos à nicotina

OBJETIVO: Investigar os possíveis efeitos da laserterapia com laser diodo 830nm ao se contrapor a ação da nicotina na viabilidade do retalho cutâneo em ratos. MÉTODOS: Foram utilizados 16 ratos Wistar, distribuídos em 2 grupos de 8: Grupo 1- submetido à técnica cirúrgica, para obtenção dos retalhos cutâneos randômicos de base cranial, com injeção subcutânea de nicotina em uma dose de 2mg/Kg/dia, uma semana antes e uma semana após o procedimento cirúrgico e simulação da radiação laser; Grupo 2- similar ao grupo 1, cujos retalhos cutâneos randômicos de base cranial foram submetidos à irradiação do laser imediatamente após a cirurgia e nos 4 dias subsequentes. Após a eutanásia, as áreas de necrose e de tecido viável foram examinadas através do método de pesagem do Gabarito de Papel e pelo método semi-automático de análise de imagens (Mini-Mop®). RESULTADOS: Os resultados foram analisados estatisticamente através do teste ANOVA. Os valores de porcentagem de área de necrose através do método de análise mostraram uma diminuição da área de necrose no grupo 2 onde foi aplicado laser. CONCLUSÃO: O laser 830nm foi eficaz na melhora da viabilidade do retalho cutâneo em ratos submetido à ação da nicotina. Nível de evidência II: Estudos terapêuticos - Investigação dos resultados do tratamento.

Targeted increase in cerebral blood flow by transcranial near-infrared laser irradiation

BACKGROUND AND OBJECTIVE

Brain function is highly dependent on cerebral blood flow (CBF). The precise mechanisms by which blood flow is controlled by NIR laser irradiation on the central nervous system (CNS) have not been elucidated. In this study, we examined the effect of 808 nm laser diode irradiation on CBF in mice.

STUDY DESIGN/MATERIALS AND METHODS

We examined the effect of NIR irradiation on CBF at three different power densities (0.8, 1.6 and 3.2 W/cm(2)) and directly measured nitric oxide (NO) in brain tissue during NIR laser irradiation using an amperometric NO-selective electrode. We also examined the contribution of NO and a neurotransmitter, glutamate, to the regulation of CBF by using a nitric oxide synthase (NOS) inhibitor, N(g)-nitro-L-arginine methyl ester hydrochloride (L-NAME), and an N-methyl-D-aspartate (NMDA) receptor blocker, MK-801, respectively. We examined the change in brain tissue temperature during NIR laser irradiation. We also investigated the protection effect of NIR laser irradiation on transient cerebral ischemia using transient bilateral common carotid artery occlusion (BCCAO) in mice.

RESULTS

We showed that NIR laser irradiation (1.6 W/cm(2) for 15-45 minutes) increased local CBF by 30% compared to that in control mice. NIR laser irradiation also induced a significant increase in cerebral NO concentration. In mice that received L-NAME, NIR laser irradiation did not induce any increase in CBF. Mice administered MK-801 showed an immediate increase but did not show a delayed additional increase in local CBF. The increase in brain tissue temperature induced by laser irradiation was estimated to be as low as 0.8 degrees C at 1.6 W/cm(2), indicating that the heating effect is not a main mechanism of the CBF increase in this condition. Pretreatment with NIR laser irradiation improved residual CBF and reduced the numbers of apoptotic cells in the hippocampus.

CONCLUSION

Our data suggest that NIR laser irradiation is a promising experimental and therapeutic tool in the field of cerebral circulation research.

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

OBJECTIVE

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

Combination 830-nm and 633-nm light-emitting diode phototherapy shows promise in the treatment of recalcitrant psoriasis: preliminary findings

BACKGROUND AND OBJECTIVES

Psoriasis is one of the major problems facing dermatologists worldwide. Planar arrays of light-emitting diodes (LEDs) have recently attracted attention in the treatment of difficult dermatological entities, 830 nm in near infrared (near-IR) and 633 nm in visible red. This study was designed to assess the efficacy of combination 830-nm and 633-nm LED phototherapy in the treatment of recalcitrant psoriasis.

SUBJECTS AND METHODS

Nine informed and consenting patients with psoriasis were enrolled in this preliminary study, (3 men, 6 women, mean age 34.3, skin types I to IV). All had chronic psoriasis, which in most cases had proved resistant to conventional treatments. They were treated sequentially with LED arrays delivering continuous-wave 830 nm (near-IR) and 633 nm (red) in two 20-min sessions over 4 or 5 weeks, with 48 h between sessions (830 nm, 60 J/cm(2); 633 nm, 126 J/cm(2)).

RESULTS

All patients completed their LED regimens (4 requiring 1 regimen, 5 requiring a second). Follow-up periods were from 3 to 8 months, except in two patients who were lost to follow-up. Clearance rates at the end of the follow-up period ranged from 60% to 100%. Satisfaction was universally very high.

CONCLUSIONS

The antiinflammatory effects of LED energy at 830 nm and 633 nm have been well documented, as has their use in wound healing. LED phototherapy is easy to apply, pain free and side-effect free, and is well tolerated by patients of all skin types. The promising results of this preliminary study warrant a proper controlled double-blind study with a larger patient population.

Psychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead: a pilot study of 10 patients with major depression and anxiety

Background

Many studies have reported beneficial effects from the application of near-infrared (NIR) light photobiomodulation (PBM) to the body, and one group has reported beneficial effects applying it to the brain in stroke patients. We have reported that the measurement of a patient's left and right hemispheric emotional valence (HEV) may clarify data and guide lateralized treatments. We sought to test whether a NIR treatment could 1. improve the psychological status of patients, 2. show a relationship between immediate psychological improvements when HEV was taken into account, and 3. show an increase in frontal pole regional cerebral blood flow (rCBF), and 4. be applied without side effects.

Methods

We gave 10 patients, (5 M/5 F) with major depression, including 9 with anxiety, 7 with a past history of substance abuse (6 with an opiate abuse and 1 with an alcohol abuse history), and 3 with post traumatic stress disorder, a baseline standard diagnostic interview, a Hamilton Depression Rating Scale (HAM-D), a Hamilton Anxiety Rating Scale (HAM-A), and a Positive and Negative Affect Scale (PANAS). We then gave four 4-minute treatments in a random order: NIR to left forehead at F3, to right forehead at F4, and placebo treatments (light off) at the same sites. Immediately following each treatment we repeated the PANAS, and at 2-weeks and at 4-weeks post treatment we repeated all 3 rating scales. During all treatments we recorded total hemoglobin (cHb), as a measure of rCBF with a commercial NIR spectroscopy device over the left and the right frontal poles of the brain.

Results

At 2-weeks post treatment 6 of 10 patients had a remission (a score ≤ 10) on the HAM-D and 7 of 10 achieved this on the HAM-A. Patients experienced highly significant reductions in both HAM-D and HAM-A scores following treatment, with the greatest reductions occurring at 2 weeks. Mean rCBF across hemispheres increased from 0.011 units in the off condition to 0.043 units in the on condition, for a difference of 0.032 (95% CI: -0.016, 0.080) units, though this result did not reach statistical significance. Immediately after treatment the PANAS improved to a significantly greater extent with NIR "on" relative to NIR "off" when a hemisphere with more positive HEV was treated than when one with more negative HEV was treated. We observed no side effects.

Conclusion

This small feasibility study suggests that NIR-PBM may have utility for the treatment of depression and other psychiatric disorders and that double blind randomized placebo-controlled trials are indicated.

Trial registration

ClinicalTrials.gov Identifier: NCT00961454

Effects of diode laser therapy on the acellular dermal matrix

Acellular dermal matrix (ADM) was subcutaneously implanted into calvarian skin of male Wistar rats (n = 40). Low-level laser (lambda 685 nm, 4 J/cm(2)) was locally applied in experimental group (n = 20) above the skin flap. Grafts were harvested at 1, 3, 7 and 14 days after surgery and underwent histological analyses. In treated animals, the extent of edema and the number of inflammatory cells were reduced (P < 0.05). The amount of collagen in graft treated with low-level laser were significantly higher than those of controls (P < 0.05) and were statistically more prominent on the 14th day after surgery. The mean count of fibroblasts was significantly higher in the low-laser therapy group within the 3rd day, showing a marked influx of fibroblasts into area. In conclusion, wound healing of the ADM appear to be positively affected by laser therapy.

Defocused diode laser therapy (830 nm) in the treatment of unresponsive skin ulcers: a preliminary trial

BACKGROUND

Skin ulcers with compromised healing remain a major problem for plastic and dermatological surgeons. Low incident levels of laser energy have been shown to increase the blood flow rate and volume and to accelerate the wound healing process, thus raising the possibility in augmenting treatment for skin ulcers.

METHODS

Preliminary controlled experiments with a 830 nm GaAlAs diode laser in axial pattern flap survival in the rat model showed statistically significant improvement in survival for the irradiated versus unirradiated control animals. In the present study, a newly developed defocused GaAlAs diode laser (830 nm, continuous wave, 669 mW/cm(2)) was applied once or twice per week in an uncontrolled study of five patients (aged between 5 and 81 years old, average 46.6 years old, doses from 6.3 J/cm(2) to 21 J/cm(2)) with previously unresponsive ulcers of various aetiologies.

RESULTS

In all five patients, the ulcers healed completely between 3 weeks and 7 months (22.8 +/- 19.3 weeks), without recurrence during a minimum 12-month follow-up.

CONCLUSIONS

Defocused 830 nm diode laser therapy was well tolerated, and was very effective in the treatment of this small number of compromised skin ulcers of different aetiologies and in a large range of patient ages. Further controlled studies in larger populations are required. Defocused diode laser therapy nonetheless appears to be a very useful adjunctive method in the treatment of slow-to-heal and non-healing skin ulcers.

Review of laser speckle contrast techniques for visualizing tissue perfusion

When a diffuse object is illuminated with coherent laser light, the backscattered light will form an interference pattern on the detector. This pattern of bright and dark areas is called a speckle pattern. When there is movement in the object, the speckle pattern will change over time. Laser speckle contrast techniques use this change in speckle pattern to visualize tissue perfusion. We present and review the contribution of laser speckle contrast techniques to the field of perfusion visualization and discuss the development of the techniques.

Effects of a single near-infrared laser treatment on cutaneous wound healing: Biometrical and histological study in rats

BACKGROUND

Low intensity laser therapy has been recommended to support the cutaneous repair; however, so far studies do not have evaluated the tissue response following a single laser treatment. This study investigated the effect of a single laser irradiation on the healing of full-thickness skin lesions in rats.

METHODS

Forty-eight male rats were randomly divided into three groups. One surgical lesion was created on the back of rats using a punch of 8mm in diameter. One group was not submitted to any treatment after surgery and it was used as control. Two energy doses from an 830-nm near-infrared diode laser were used immediately post-wounding: 1.3 J cm(-2) and 3 J cm(-2). The laser intensity 53 m W cm(-2) was kept for both groups. Biometrical and histological analyses were accomplished at days 3, 7 and 14 post-wounding.

RESULTS

Irradiated lesions presented a more advanced healing process than control group. The dose of 1.3 J cm(-2) leaded to better results. Lesions of the group irradiated with 1.3 J cm(-2) presented faster lesion contraction showing quicker re-epithelization and reformed connective tissue with more organized collagen fibers.

CONCLUSIONS

Low-intensity laser therapy may accelerate cutaneous wound healing in a rat model even if a single laser treatment is performed. This finding might broaden current treatment regimens.

The importance of coherence length in laser phototherapy of gingival inflammation—a pilot study

The aim of this study was to investigate if coherence length is of importance in laser phototherapy. Twenty patients with moderate periodontitis were selected. After oral hygiene instructions, scaling and root planing (SRP), one side of the upper jaw was randomly selected for HeNe (632.8 nm, 3 mW) or InGaAlP (650 nm, 3 mW) laser irradiation. One week after SRP, the following parameters were measured: pocket depth, gingival index, plaque index, gingival crevicular fluid volume, matrix metalloproteinase (MMP-8), interleukin (IL-8) and subgingival microflora. The irradiation (180 s per point, energy 0.54 J) was then performed once a week for 6 weeks. At the follow up examination, all clinical parameters had improved significantly in both groups. A more pronounced decrease of clinical inflammation was observed after HeNe treatment. MMP-8 levels were considerably reduced on the HeNe side, while there was no difference for IL-8 or microflora. Coherence length appears to be an important factor in laser phototherapy.

Short-Time Effects of Laser Needle Stimulation on the Peripheral Microcirculation Assessed by Laser Doppler Spectroscopy and Near-Infrared Spectroscopy

OBJECTIVE

The aim of the present study was to evaluate immediate effects of a standardized laser needle stimulation over a defined acupuncture point on the microvascular blood flow and muscle oxygenation in the human forearm.

BACKGROUND DATA

Recently, it has been shown that laser stimulation improves tissue perfusion. This is relevant since adequate blood supply is an important factor in the treatment of pain syndromes.

METHODS

The study was designed as a randomized, double-blinded, placebo-controlled trial. Thirty-three healthy non-smoking males were randomly assigned to a control group (n = 15) with no laser irradiation and to an intervention group (n = 18) for which laser needle irradiation was performed on the right forearm at acupuncture point Pe6. Non-invasive blood flow measurements (laser Doppler spectroscopy [LDS]) were performed before, during, and after intervention. Additionally, the dynamic changes in muscle oxygenation of the m. flexor carpi ulnaris were investigated using near-infrared spectroscopy (NIRS).

RESULTS

Repeated measures MANOVA demonstrated a statistically significant interaction between time and group (p = 0.034, effect size = 0.39), indicating that peripheral blood flow was influenced by laser needle application. In contrast, tissue oxygenation was not affected by the experimental treatment.

CONCLUSION

It has been demonstrated that laser needle stimulation may improve peripheral microcirculation under standardized conditions, whereas tissue oxygenation remained unchanged. Further research is required to determine the influence of various parameter settings and irradiation treatments on the peripheral microcirculation. Moreover, different acupuncture points should be investigated in order to appraise the clinical effectiveness of laserneedle stimulation.