830-nm irradiation increases the wound tensile strength in a diabetic murine model.
Stadler I, Lanzafame RJ, Evans R, Narayan V, Dailey B, Buehner N, Naim JO.
The Laser Center, Rochester General Hospital, Rochester, New York 14621, USA. Istvan.Stadler@viahealth.org
Lasers Surg Med. 2001;28(3):220-6.[PMID: 11295756]
Background and objective: The purpose of this study was to investigate the effects of low-power laser irradiation on wound healing in genetic diabetes.
Study design/materials and methods: Female C57BL/Ksj/db/db mice received 2 dorsal 1 cm full-thickness incisions and laser irradiation (830 nm, 79 mW/cm(2), 5.0 J/cm(2)/wound). Daily low-level laser therapy (LLLT) occurred over 0-4 days, 3-7 days, or nonirradiated. On sacrifice at 11 or 23 days, wounds were excised, and tensile strengths were measured and standardized.
Results: Nontreated diabetic wound tensile strength was 0.77 +/- 0.22 g/mm(2) and 1.51 +/- 0.13 g/mm(2) at 11 and 23 days. After LLLT, over 0-4 days tensile strength was 1.15 +/- 0.14 g/mm(2) and 2.45 +/- 0.29 g/mm(2) (P = 0.0019). Higher tensile strength at 23 days occurred in the 3- to 7-day group (2.72 +/- 0.56 g/mm(2) LLLT vs. 1.51 +/- 0.13 g/mm(2) nontreated; P < or = 0.01).
Conclusion: Low-power laser irradiation at 830 nm significantly enhances cutaneous wound tensile strength in a murine diabetic model. Further investigation of the mechanism of LLLT in primary wound healing is warranted.
Copyright 2001 Wiley-Liss, Inc.
A Preliminary Double-Blind Controlled Study on Free Amino Acid Analysis in Burn Wounds in the Mouse Following 830 nm Diode Laser Therapy
Sasaki, T. Ohshiro, and T. Hoshino
Ohshiro Clinic, Shinanomachi, Japan Medical Laser Laboratory, Shinanomachi, and Department of Biochemistry, Keio University School of Medicine, Shinanomachi, Tokyo, Japan
Abstract: A double-blind controlled study is presented on the amino acid analysis of levels of a selected group of 26 free amino acids (FAA) in CO2 laser generated standardized burn wounds on the bilateral dorsum in the ddy mouse model. Four groups of ddy white mice (male, 5 weeks old, average weight 20 g), 6 animals per group, were anaesthetized with ether. The hair on the bilateral dorsum of all animals was carefully removed with a depilatory cream, and in three of the groups standardized burn injuries were inflicted using the defocused beam of the CO2 laser (25 W, continuous wave, 1.45 cm diameter spot, 0.99 sec/shot). The injuries were made bilaterally 1 cm laterally from the dorsal midline, 1.5 cm caudally from the line drawn between the base of the ears. The 4th group was the unburned control group for assessing base FAA levels. In experimental group A (LLLT group), the centre of the right hand burn injury was irradiated daily on days 0, 1, 2, 3, 4, and 5 with an 830 nm GaAlAs diode laser system (60 mW continuous wave). The left hand injury was unirradiated. The laser was held 1 mm from the surface of the wound, giving a spot size of approximately 0.03 cm2, 20 sec per exposure per day, energy density per exposure of 40 J/cm2. Group B (sham irradiation group) was handled in exactly the same way, but a non-emitting probe was used. Group C (unirradiated burned controls) was not handled at all. The animals were killed (ether overdose) on post-burn day 10. The size of the burn injury and the degree of wound healing were measured macroscopically on days 2, 5 and 7 and 10. The LLLT group A demonstrated better wound healing than groups B and C, between which there was no difference. On days 0, 1, 3, 5, 7 and 10, sample tissue was collected from both burned sites in the burned animals and from the unburned controls and subjected to automated AA analysis. The unburned controls were used as standards. On day 7 specimens were taken from the burn wounds in groups A, B and C and routinely processed for histological assessment with haematoxylin and eosin and elastica van Giesen’s stains. Automated AA analysis in general revealed higher levels of total FAA in group A, with no statistical difference between groups B and C. When looked at individually as spider graphs, the 26 AA isolated in this study at fell into 6 typical patterns. At day 10 histology revealed more advanced wound healing between the LLLT group and groups B and C, between which there was no difference. although the present study was only designed to isolate patterns in FAA associated with healing burns, the authors conclude that 830 nm diode LLLT certainly appears to accelerate wound healing, and there is a higher level of those FAA associated with protein synthesis.
A case report of low-intensity laser therapy (LILT) in the management of venous ulceration: potential effects of wound debridement upon efficacy.
Lagan KM, Mc Donough SM, Clements BA, Baxter GD.
Rehabilitation Sciences Research Group, School of Health Sciences, University of Ulster at Jordanstown, BT37 OQB, North Ireland.
J Clin Laser Med Surg. 2000 Feb;18(1):15-22. [PMID: 11189107]
Objective: This single case report (ABA design) was undertaken as a preliminary investigation into the clinical effects of low intensity laser upon venous ulceration, applied to wound margins only, and the potential relevance of wound debridement and wound measurement techniques to any effects observed.
Methods: Ethical approval was granted by the University of Ulster’s Research Ethical Committee and the patient recruited was required to attend 3 times per week for a total of 8 weeks. Treatments were carried out using single source irradiation (830 nm; 9 J/cm2, CB Medico, Copenhagen, Denmark) in conjunction with dry dressings during each visit. Assessment of wound surface area, wound appearance, and current pain were completed by an independent investigator. Planimetry and digitizing were completed for wound tracings and for photographs to quantify surface areas. Video image analysis was also performed on photographs of wounds.
Results: The primary findings were changes in wound appearance, and a decrease in wound surface area (range 33.3-46.3%), dependent on the choice of measurement method. Video image analysis was used, but rejected as an accurate method of wound measurement. Treatment intervention produced a statistically significant reduction in wound area using the C statistic on digitizing data for photographs (at Phase one only; Z = 2.412; p < 0.05). Wound debridement emerged as an important procedure to be carried out prior to measuring wounds. Despite fluctuating pain levels recorded throughout the duration of the study, VAS scores showed a decrease of 15% at the end of the study. This hypoalgesic effect was, however, statistically significant (using the C statistic) at Phase one only (Z = 2.554; p < 0.05).
Conclusions: Low intensity laser therapy at this dosage, and using single source irradiation would seem to be an effective treatment for patients suffering venous ulceration. Further group studies are indicated to establish the most effective therapeutic dosage for this and other types of ulceration.
Analysis of Low-Level Laser Radiation Transmission in Occlusive Dressings
de Jesus Guirro RR, de Oliveira Guirro EC, Martins CC, Nunes FR.
Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, School of Medicine of Ribeirã o Preto, University Sã o Paulo, Brazil
Photomed Laser Surg. 2009 Oct 9. [PMID: 19817516]
Objective: The purpose of this study is to analyze the power transmitted by low-level laser therapy (LLLT) into occlusive dressings using different wavelengths for the treatment of cutaneous lesions.
Background data: LLLT has been largely used to treat several cutaneous lesions commonly associated with occlusive dressings to accelerate the healing process.
Materials and methods: Radiation transmission was measured by a digital power analyzer connected to a laser emitter with wavelengths of 660, 830, and 904 nm and mean levels of 30, 30, 6.5 mW, respectively, previously calculated. Thirteen different occlusive dressings were analyzed and interposed between the laser emitter and the power analyzer sensor, with 15 measurements made for each dressing. Statistics were provided by the analysis of variance (ANOVA), followed by Student’s t-test (p < 0.05).
Results: The power transmitted ranged between 98.6% and 0%, depending on the material and wavelength. The dressings tested were BioFill, Hydrofilm, Confeel Plus 3533, Confeel 3218, DuoDERM Extra Thin, Hydrocoll, Micropore Nexcare, CIEX tape, Emplasto Sábia, CombiDERM, Band-aid, Actisorb Plus, in addition to polyvinylchloride (PVC) film, and transmitted power higher than 40% of the incident power, independently from the wavelength indicated for the association with LLLT.
Conclusion: The results showed that LLLT transmission depends on the occlusive dressing material and the wavelength irradiated.
Dose and wavelength of laser light have influence on the repair of cutaneous wounds
Mendez TM, Pinheiro AL, Pacheco MT, Nascimento PM, Ramalho LM.
IP&D, Univap & School of Dentistry, Universidade do Vale do Paraí ba, Sã o José dos Campos, Sã o Paulo, Brazil.
J Clin Laser Med Surg. 2004 Feb;22(1):19-25. [PMID: 15117483]
Objective: The objective of the present study was to compare histologically the effect of GaAlAs (lambda 830 nm, phi approximately 2 mm(2), 35 mW) and InGaAlP (lambda 685 nm, phi approximately 2 mm(2), 35 mW) lasers, alone or in association with doses of 20 or 50 J/cm(2) on cutaneous wounds in the dorsum of the Wistar rat.
Background data: The healing time of surgical wounds is of extreme importance and it is usually associated with a post-operative period free of infection and with less pain and inflammation.
Materials and methods: Sixty Wistar rats were divided into seven groups: Group I – control (non-irradiated); Group II – lambda 685 nm, 20 J/cm(2); Group III – lambda 830 nm, 20 J/cm(2); Group IV – lambda 685 nm and lambda 830 nm, 20 J/cm(2); Group V – lambda 685 nm, 50 J/cm(2)); Group VI – lambda 830 nm, 50 J/cm(2); and Group VII – lambda 685 nm and 830 nm, 50 J/cm(2). The animals were sacrificed 3, 5, and 7 days after surgery.
Results: Light microscopic analysis using H&E and Picrosírius stains showed that, at the end of the experimental period, irradiated subjects showed increased collagen production and organization when compared to non-irradiated controls. Inflammation was still present in all groups at this time.
Conclusion: Group IV (lambda 830 nm and lambda 685 nm, 20 J/cm(2)) presented better results at the end of the experimental period. It is concluded that low-level light therapy (LLLT) can have a positive biomodulatory effect on the repair of cutaneous wounds.
Effect of low-level laser therapy on inflammatory reactions during wound healing: comparison with meloxicam
Viegas VN, Abreu ME, Viezzer C, Machado DC, Filho MS, Silva DN, Pagnoncelli RM.
School of Dentistry, Laser Center, Pontif í cia Universidade Cató lica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.
Photomed Laser Surg. 2007 Dec;25(6):467-73. [PMID: 18158747]
Objective: This study evaluated the action of low-level laser therapy (LLLT) on the modulation of inflammatory reactions during wound healing in comparison with meloxicam.
Background data: LLLT has been recommended for the postoperative period because of its ability to speed healing of wounds. However, data in the literature are in disagreement about its anti-inflammatory action.
Methods: Standardized circular wounds were made on the backs of 64 Wistar rats. The animals were divided into four groups according to the selected postoperative therapy: group A-control; group B-administration of meloxicam; and groups C and D-irradiation with red (lambda = 685 nm) and infrared (lambda = 830 nm) laser energy, respectively. The animals were killed at 12, 36, and 72 h and 7 days after the procedure.
Results: Microscopic analysis revealed significant vascular activation of irradiated sites in the first 36 h. Only group B showed decreases in the intensity of polymorphonuclear infiltrates and edema. Group D showed a higher degree of organization and maturation of collagen fibers than the other groups at 72 h. The animals in group C showed the best healing pattern at 7 days. The anti-inflammatory action of meloxicam was confirmed by the results obtained in this research. The quantification of interleukin-1beta (IL-1beta) mRNA by real-time polymerase chain reaction (PCR) did not show any reduction in the inflammatory process in the irradiated groups when compared to the other groups.
Conclusions: LLLT improves the quality of histologic repair and is useful during wound healing. However, with the methods used in this study the laser energy did not minimize tissue inflammatory reactions.
Effects of a single near-infrared laser treatment on cutaneous wound healing: biometrical and histological study in rats.
Rezende SB, Ribeiro MS, Núñez SC, Garcia VG, Maldonado EP.
Center for Lasers and Applications, IPEN-CNEN/SP, São Paulo, SP, Brazil.
J Photochem Photobiol B. 2007 Jun 26;87(3):145-53. Epub 2007 Mar 19. [PMID: 17475503]
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.
Hyperbaric Oxygen Therapy Versus Laser Therapy on the Acceleration of Venous Leg Ulcer Healing
Emad T. Ahmad PT.D
Faculty of Physical Therapy, Cairo University Egypt
Abstract: The purpose of the current study was to determine the effectiveness of hyperbaric oxygen therapy(HBOT) or laser therapy in the acceleration of chronic venous ulcer healing. Thirty hospital inpatients with venous ulcers participated in this study for a treatment period of five weeks. They were divided randomly and equally into three groups (2 treatment groups and one control group). Patients in group (1) (HBOT group) received two 90 minutes treatments daily with 2 to3 L of humidified oxygen / minute at 22 mmHg. On the other hand, patients in group (2) (laser therapy group) received 1 J/cm2 infrared laser (Ga As), three times weekly. Patients in group (3) (control group) received standard wound care only. Wound surface area (WSA) and wound volume (WV) were used to measure the outcomes before starting the study and after the 3rd and 5th weeks posttreatment. It was found that, at the 5th week post-treatment there was a significant reduction in both WSA and WV in both the HBOT group and the laser therapy group when compared to the control group (P<0.0001), also there was a significant reduction in WSA and WV in the laser therapy group at the 5th week post-treatment when compared to the HBOT group (P<0.001). The findings strongly suggest that the application of infrared laser therapy at a dose of 1J/cm2, three times/week is more effective than the application of HBOT daily in the management of chronic venous ulcers.
Low-level laser therapy (LLLT) at 830 nm positively modulates healing of tracheal incisions in rats: a preliminary histological investigation
Grendel T, Sokolský J, Vaščáková A, Hrehová B, Poláková M, Bobrov N, Sabol F, Gál P.
Department of Medical Biophysics, Pavol Jozef Šafárik University, Košice, Slovak Republic.
Photomed Laser Surg. 2011 Sep;29(9):613-8. Epub 2011 Apr 1.[PMID: 21456943]
Objective: The aim of the present study was to evaluate whether LLLT at 830 nm is able to positively modulate trachea incisional wound healing in Sprague-Dawley rats.
Background data: Tracheotomy may be associated with numerous complications. Development of excess granulation tissue represents a late complication that may lead to airway occlusion. Low-level laser therapy (LLLT) has been shown to have stimulatory effects on wound healing of different tissues. Therefore, it may be suggested that LLLT could be able to positively modulate trachea wound healing as well.
Materials and methods: Using general anesthesia, a median incision was performed from the second to the fifth tracheal cartilage ring in 24 rats. Animals were then randomly divided into sham-irradiated control and laser-treated groups. LLLT (power density: 450 mW/cm(2); total daily dose: 60 J/cm(2); irradiated area ∼1 cm(2)) treatment was performed daily during the first week after surgery. Samples for histological evaluation were removed 7 and 28 days after surgical procedure. Histological sections were stained with hematoxylin-eosin and van Gieson.
Results: Results from our investigation showed that LLLT was able to reduce granulation tissue formation and simultaneously increase new cartilage development at both evaluated time intervals.
Conclusions: From this point of view, LLLT at 830 nm may be a valuable tool in trachea wound healing modulation. Nevertheless, further detailed research is needed to find optimal therapeutic parameters and to test these findings on other animal models.
Low-Level Laser Therapy Facilitates Superficial Wound Healing in Humans: A Triple-Blind, Sham-Controlled Study
Hopkins JT, McLoda TA, Seegmiller JG, David Baxter G.
Brigham Young University, Provo, UT.
J Athl Train. 2004 Sep;39(3):223-229. [PMID: 15496990]
Allied health professionals regularly care for a variety of wounds to the skin, among them abrasions, turf burns, surgical incisions, and, perhaps the most difficult to treat, ulcerations. From acute wound management to augmentation of scar tissue remodeling, the clinician seeks to optimize wound care to promote healing. Although low-level laser therapy (LLLT) has received only specified US Food and Drug Administration clearance, its clinical efficacy for tissue healing has been widely reported.1–5 In vitro data suggest that LLLT facilitates collagen synthesis,6 keratinocyte cell motility,7 and growth factor release8 and transforms fibroblasts to myofibroblasts.9 Many authors of clinical studies have reported the benefits of LLLT on tissue healing, but others have shown no effect.10–13 These conflicting results are likely due to variations in treatment factors and limitations in experimental design, including comparison of heterogeneous clinical wounds, lack of control groups, and limited or no blinding of investigators.14,15
Several researchers have used superficial wounds to assess the putative effects of LLLT on healing.15 Some have used clinical wounds or ulcers of various sizes and depths,1,2,12 and others have developed superficial wound models in animals.10,11,16,17 These different methods have produced varied results and conclusions as to the effectiveness of LLLT. When analyzing healing among wounds, it would be beneficial if the wounds were as alike as possible; therefore, the differences in healing could be attributed to the treatment and not to other factors, such as wound variability. Claus et al18 developed a superficial wound model for use in human subjects that controlled for wound size and depth. This model allows for evaluation of partial-thickness abrasions of controlled size and depth at measurement intervals set by the investigator.
Our purpose was to assess potential changes in healing due to LLLT over time using a human experimental wound model. Healing was measured in terms of wound contraction and changes in chromatic red and luminance. Chromatic red is an indication of wound healing as a wound changes in color from dark red to pale pink over time. Luminance refers to the homogeneity of a wound as the tissue heals and becomes more smooth and consistent.
Low-Level Laser Therapy in Ambulatory Patients with Venous Stasis Ulcers
- Lichtenstein FICA, B. Morag
Maccabi Health Care Services and Department of Vascular Surgery, Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv Israel
Abstract: The effectiveness of laser therapy in accelerating wound healing has been clinically well documented. We used two devices: one, a He-Ne laser with a wavelength of 632.8nm and power output of 8mW; the other, a Ga-Al-As laser with a wavelength of 830nm and power output of 120mW. The indication for treatment was stasis ulcers (Ulcer cruris) due to chronic venous insufficiency syndrome. Sixty-two patients were treated in this study. The challenge of obtaining good results when treating patients with long-standing vascular ulcers and wounds caused us to explore this technique. We achieved complete wound healing, classified as good, in 53 patients (85.48%) of the patients during a two to 14 week period of treatment, and moderate partial wound closure with clinical improvement in 4 patients (6.46%) with chronic long-term venous leg ulcers. The efficiency of the treatment was 91.94%. No patient had to stop treatment because of adverse side effects. Two patients (3.2%), had recurrent ulcers. These findings indicate that appropriate doses of laser can be beneficial in promoting tissue repair.
Treatment of Skin Ulcers with 830 nm GaAIAs Diode Laser Therapy.
Department of Plastic and Reconstructive Surgery, Kyorin University School of Medicine, Tokyo, Japan.
Abstract: Persistant skin ulcers are still a major problem for the plastic and reconstructive surgeon. These ulcers of various aetiologies are often resistant to conventional therapeutic methodologies and present both patient and surgeon with severe problems. Low-level laser therapy (LLLT) has been proved to accelerate wound healing by enhancing blood flow, macrophage activity, and lymphatic drainage in the inflammatory stage; by increasing fibroblast proliferation and collagen deposition in the proliferative stage; by encouraging more fibroblast to myofibroblast trasformation in the contractile stage; and by assisting with remodeling in the final stage of repair. It was considered that these LLLT associated actions, coupled with others, would be of assistance in treating persistent ulcers in a painless, side-effect free and noninvasive manner. The laser used was a near-infrared 830 nm gallium aluminum arsenide (GaAIAs) semiconductor laser delivering 150 mW in continuous wave. The laser was applied in the contact mode for 15 to 30 sec per point, irradiating the intact skin around the periphery of the ulcer. The incident energy density was approximately 66 J/cm2 or 132 J/cm2 per point, depending on the exposure time. Nine representative case reports are presented of persistent therapy-resistant ulcers of a variety of aetiologies which responded very well to 830 nm diode LLLT. Although further research is needed to elucidate completely the mechanisms and pathways of LLLT in wound healing enhancement, enough has been scientifically proved to date to justify the application of LLLT for persistent ulcers as a safe, effective, painless, and side effect free modality, particularly when used as an adjunctive therapy together with good wound care.
Wound healing of animal and human body sport and traffic accident injuries using low-level therapy treatment; a randomized clinical study of seventy-four patients with control group
Simunovic Z, Ivankovich AD, Depolo A.
Journal of Clinical Laser Medicine and Surgery (2000) Apr;18(2):67-73
Background and objective: The main objective of current animal and clinical studies was to assess the efficacy of low level laser therapy (LLLT) on wound healing in rabbits and humans.
Study design/materials and methods: In the initial part of our research we conducted a randomized controlled animal study, where we evaluated the effects of laser irradiation on the healing of surgical wounds on rabbits. The manner of the application of LLLT on the human body are analogous to those of similar physiologic structure in animal tissue, therefore, this study was continued on humans. Clinical study was performed on 74 patients with injuries to the following anatomic locations: ankle and knee, bilaterally, Achilles tendon; epicondylus; shoulder; wrist; interphalangeal joints of hands, unilaterally. All patients had had surgical procedure prior to LLLT. Two types of laser devices were used: infrared diode laser (GaAlAs) 830 nm continuous wave for treatment of trigger points (TPs) and HeNe 632.8 nm combined with diode laser 904-nm pulsed wave for scanning procedure. Both were applied as monotherapy during current clinical study. The results were observed and measured according to the following clinical parameters: redness, heat, pain, swelling and loss of function, and finally postponed to statistical analysis via chi2 test.
Results: After comparing the healing process between two groups of patients, we obtained the following results: wound healing was significantly accelerated (25%-35%) in the group of patients treated with LLLT. Pain relief and functional recovery of patients treated with LLLT were significantly improved comparing to untreated patients.
Conclusion: In addition to accelerated wound healing, the main advantages of LLLT for postoperative sport- and traffic-related injuries include prevention of side effects of drugs, significantly accelerated functional recovery, earlier return to work, training and sport competition compared to the control group of patients, and cost benefit.