Low-Level Laser Therapy and Cryotherapy as Mono- and Adjunctive Therapies for Achilles Tendinopathy in Rats.
- 11 NorPhyPain Research Group, Faculty of Health and Social Sciences, Centre for Evidence Based Practice, Bergen University College , Bergen, Norway .
- 22 Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen , Bergen, Norway .
- 33 Nucleus of Technological Research-NPT, Post-Graduate Program in Biomedical Engeneering, University of Mogi das Cruzes (UMC) , São Paulo, Brazil .
- 44 Centro de Ciências da Saúde, Universidade Cruzeiro do Sul , São Paulo, Brazil .
- 55 Programa de Pós-Graduação em Biofotônica Aplicada as Ciências da Saúde, Universidade Nove de Julho , São Paulo, Brazil .
- 66 Department of Occupational Therapy, Physiotherapy and Radiography, Faculty of Health and Social Sciences, Bergen University College , Bergen, Norway .
BACKGROUND AND OBJECTIVE:
Low-level laser therapy (LLLT) and cryotherapy are widely used treatments in the acute phase of tendon injury. The aim of this study was to investigate the interaction of these two treatments on tendon inflammation and mechanical properties.
MATERIALS AND METHODS:
Six groups of six Wistar rats were used in this study. The Achilles tendons of the healthy control group were not subjected to injury or treatment. The tendons of the injured nontreated group (ING) were injured, but not treated. The remaining four groups were injured and subjected to LLLT, cryotherapy, LLLT first/cryotherapy, or cryotherapy first/LLLT. All treatments were performed at 1?h post-trauma. Inflammatory mediators, tendon histology, and biomechanical properties were assessed at 24?h post-trauma by comparing the treatment groups with the ING.
In all treatment groups, the inflammatory process shifted in an anti-inflammatory direction compared with the ING. Significant alterations in cytokine expression were found in only the LLLT group (?IL-1?) and the combined intervention groups (?IL-1?, ?TNF-?, ?IL-6). It was also found that cryotherapy followed by LLLT was the only treatment that significantly (p?<?0.05) improved the biomechanical parameters of force (N) and displacement (mm) at the tendon rupture and corresponded with the best histological scores of all of the treatment groups.
Our results demonstrate that cryotherapy in combination with LLLT can produce an anti-inflammatory “add-on” effect. The order of therapy administration seems essential, as superior histology and biomechanical results were found in the cryotherapy first/LLLT group
Low-level laser therapy modulates pro-inflammatory cytokines after partial tenotomy.
- 1Department of Anatomy, Institute of Biomedical Science, Federal University of Alfenas – UNIFAL-MG, 37130-000, Alfenas, MG, Brazil. email@example.com.
- 2Department of Structural and Functional Biology, Institute of Biology, CP 6109, University of Campinas – UNICAMP, 13083-970, Campinas, SP, Brazil.
- 3Department of Biochemistry, Institute of Biomedical Science, Federal University of Alfenas – UNIFAL-MG, 37130-000, Alfenas, MG, Brazil.
- 4Department of Anatomy, Institute of Biomedical Science, Federal University of Alfenas – UNIFAL-MG, 37130-000, Alfenas, MG, Brazil.
Tendon injuries give rise to substantial morbidity, and current understanding of the mechanisms involved in tendon injury and repair is limited. This lesion remains a clinical issue because the injury site becomes a region with a high incidence of recurrent rupture and has drawn the attention of researchers. We already demonstrated that low-level laser therapy (LLLT) stimulates the synthesis and organization of collagen I, MMP-9, and MMP-2 and improved the gait recovery of the treated animals. The aim of this study was to evaluate the effects of LLLT in the nitric oxide and cytokines profile during the inflammatory and remodeling phases. Adult male rats were divided into the following groups: G1-intact, G2- injured, G3-injured + LLLT (4 J/cm2 continuous), G4-injured + LLLT (4 J/cm2-20 Hz-pulsed laser). According to the analysis, the animals were euthanized on different dates (1, 4, 8, or 15 days after injury). ELISA assay of TNF-a, IL-1B, IL-10, and TGF-B was performed. Western blotting of isoform of nitric oxide synthase (i-NOS) and nitric oxide dosage experiments was conducted. Our results showed that the pulsed LLLT seems to exert an anti-inflammatory effect over injured tendons, with reduction of the release of proinflammatory cytokines, such as TNF-a and the decrease in the i-NOS activity. Thanks to the pain reduction and the facilitation of movement, there was a stimulation in the TGF-B and IL-1B release. In conclusion, we believe that pulsed LLLT worked effectively as a therapy to reestablish the tendon integrity after rupture.
Photobiomodulation and eccentric exercise for Achilles tendinopathy: a randomized controlled trial.
- 1Centre for Health, Activity & Rehabilitation Research, University of Otago, Dunedin, New Zealand. firstname.lastname@example.org.
- 2Centre for Health, Activity & Rehabilitation Research, University of Otago, Dunedin, New Zealand.
The common regime of eccentric exercise in use for Achilles tendinopathy is somewhat arduous and compliance issues can arise. This is the first study to investigate the effectiveness of a regime of fewer exercise sessions combined with photobiomodulation for the treatment of Achilles tendinopathy.
A double blind randomized controlled trial and intention-to-treat analysis were performed. Eighty participants, 18-65 years with Achilles tendinopathy and symptoms for longer than 3 months, were included in the trial. Participants randomized into one of four groups; 1 (Placebo + Ex Regime 1) or 2 (Laser + Ex Regime 1) or 3 (Placebo + Ex Regime 2) or 4 (Laser + Ex Regime 2). The primary outcome measure was the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. Outcomes were collected at baseline, week 4 and week 12.
Sixteen participants were lost to follow-up at 12 weeks, 4 of which due to adverse reactions. As per intention to treat, missing data were imputed, 80 participants were included in the final analysis. For VISA-A at 12 weeks, group 4 achieved significant gains over the other 3 groups: group 1 (18.5 [9.1, 27.9]), group 2 (10.4 [1.5, 19.2]), group 3 (11.3 [3.0, 19.6]). There was a moderate effect size in favour of exercise twice per week (7.2 [-1.8, 16.2], ES .7).
Twice-daily exercise sessions are not necessary as equivalent results can be obtained with two exercise sessions per week. The addition of photobiomodulation as adjunct to exercise can bring added benefit.
The effects of laser treatment in tendinopathy: a systematic review.
1Universidade Estadual do Piauí, Centro de Ciências da Saúde, Teresina, PI, Brazil, Centro de Ciências da Saúde (CCS) da Universidade Estadual do Piauí, Teresina, PI, Brazil.
Tendons have as main function transmit forces from the muscle to the bones. Tendinopathy is an inflammatory process that occurs in and around the tendon, when these are affected by some injury. Low level laser therapy consists in a local application of a monochromatic, coherent and short wavelength light. Its use began in 60’s and since then several benefits for tendon injuries have been reported. The objective of this study is to collect the most recent studies about the use of laser on the tendinopathy treatment. We performed searches on the following electronic databases PubMed, Medline, CAPES journals portal and LILACS. After the analysis, we selected three articles that showed that the use of low-level laser therapy, compared to placebo, is effective in treatment of tendinopathy. Despite the need for more studies about this theme, the low-level laser therapy demonstrates consistent results in the treatment of tendinopathy.
Low–Level Laser Therapy on Tissue Repair of Partially Injured Achilles Tendon in Rats.
Abstract Objective: The aim of this study was to assess the alignment and type of collagen (I and III) in partially injured Achilles tendons of rats treated with low–level laser therapy (LLLT).
Background: Achilles tendons present high indices of injury and their regeneration process may take a long time. LLLT has been used to accelerate and enhance injured Achilles tendon repair.
Methods: Sixty-five male Wistar rats were distributed into seven groups: LASER 1, 3, and 7 (the rat’s Achilles tendons were partially injured and submitted to treatment for 1, 3, or 7 days, respectively); a Sham group 1, 3, and 7 for each of LASER group (same injury, but the LLLT was only simulated), and five remaining animals were allocated to the control group (no procedures were performed). The 780?nm LLLT was applied once a day, with 70?mW of mean power, fluence of 17.5?J/cm2 for 10?sec. After the rats were euthanized, the tendons were surgically removed and assessed by birefringence technique (collagen alignment) and picrosirius red (collagen I and III).
Results: Sham versus LASER analysis did not show differences (p>0.05) for collagen alignment. The collagen composition (median) was significantly different (p<0.05) for LASER 3 (I: 16.5; III: 83.5) versus Sham 3 (I: 12.5; III: 87.5) and LASER 7 (I: 20.2; III: 79.8) versus Sham 7 (I: 10.2; III: 89.8). LASER groups exhibited a higher percentage of type I collagen and a lower percentage of type III collagen.
Conclusions: LLLT stimulated collagen I proliferation, improving the injured Achilles tendons’ healing process.
Mast cell curve-response in partial achilles tendon rupture after 830 nm phototherapy.
The aim of this study was to quantify mast cells at different time intervals after partial Achilles tendon rupture in rats treated with low–level laser therapy (LLLT).
There is a high incidence of lesions and ruptures in the Achilles tendon that can take weeks and even months to heal completely. As the mast cells help in the healing repair phase, and LLLT has favorable effects on this tissue repair process, study of this modality on the quantity of mastocytes in the ruptured tendon is relevant.
Sixty Wistar rats were subjected to partial Achilles‘ tendon rupture by direct trauma, randomized into 10 groups, and then divided into the group treated with 80 mW aluminum gallium arsenide infrared laser diode, continuous wave, 2.8 W/cm(2) power density, 40 J/cm(2) energy density, and 1.12 J total energy, and the simulation group. Both the groups were subdivided according to the histological assessment period of the sample, either 6 h, 12 h, 24 h, 2 days, or 3 days after the rupture, to quantify the mastocytes in the Achilles‘ tendon.
The group subjected to LLLT presented a greater quantity of mastocytes in the periods of 6 h, 12 h, 24 h, 2 days, and 3 days after rupture, compared with the simulation groups, but differences were detected between the sample assessment periods only in the simulation group.
LLLT was shown to increase the quantity of mastocytes in the assessment periods compared with the simulation groups.
Evaluating the effect of low–level laser therapy on healing of tentomized Achilles tendon in streptozotocin-induced diabetic rats by light microscopical and gene expression examinations.
Tendon healing is impaired in individuals diagnosed with diabetes mellitus (DM). According to research, there is considerable improvement in the healing of surgically tenotomized Achilles tendons following low–level laser therapy (LLLT) in non-diabetic, healthy animals. This study uses light microscopic (LM) and semi-quantitative reverse transcription PCR (RT-PCR) analyses to evaluate the ability of LLLT in healing Achilles tendons from streptozotocin-induced diabetic (STZ-D) rats. A total of 88 rats were randomly divided into two groups, non-diabetic and diabetic. DM was induced in the rats by injections of STZ. The right Achilles tendons of all rats were tenotomized 1 month after administration of STZ. Laser-treated rats were treated with a helium-neon (He-Ne) laser that had a 632.8-nm wavelength and 7.2-mW average power. Experimental group rats received a daily dose of 0.014 J (energy density, 2.9 J/cm2). Control rats did not receive LLLT. Animals were sacrificed on days 5, 10, and 15 post-operatively for semi-quantitative LM and semi-quantitative RT-PCR examinations of transforming growth factor-beta1 (TGF-?1) gene expression. The chi-square test showed that LLLT significantly reduced inflammation in non-diabetic rats compared with their non-diabetic controls (p?=?0.02). LLLT significantly decreased inflammation in diabetic rats on days 5 (p?=?0.03) and 10 (p?=?0.02) compared to the corresponding control diabetic rats. According to the student’s t test, LLLT significantly increased TGF-?1 gene expression in healthy (p?=?0.000) and diabetic (p?=?0.000) rats compared to their relevant controls. The He-Ne laser was effective in altering the inflammatory reaction and increasing TGF-?1 gene production.
Low–level laser irradiation stimulates tenocyte proliferation in association with increased NO synthesis and upregulation of PCNA and cyclins.
1Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Gueishan Township, Taoyuan County, Taiwan.
Low–level laser therapy is commonly used to treat tendinopathy or tendon injury. Tendon healing requires tenocyte migration to the repair site, followed by proliferation and synthesis of the extracellular matrix. There are few evidence to elucidate that low–level laser promote tenocyte proliferation. This study was designed to determine the effect of laser on tenocyte proliferation. Furthermore, the association of this effect with secretion of nitric oxide (NO) and the expressions of proliferating cell nuclear antigen (PCNA) and cyclins D1, E, A, and B1 was investigated. Tenocytes intrinsic to rat Achilles tendon were treated with low–level laser (660 nm). Tenocyte proliferation was evaluated by MTT assay and immunocytochemistry with Ki-67 stain. NO in the conditioned medium was measured by ELISA. Western blot analysis was used to evaluate the protein expressions of PCNA and cyclins D1, E, A, and B1. The results revealed that tenocytes proliferation was enhanced dose dependently bylaser. NO secretion was increased after laser treatment. PCNA and cyclins E, A, and B1 were upregulated by laser. In conclusion, low–level laserirradiation stimulates tenocyte proliferation in a process that is mediated by upregulation of NO, PCNA, and cyclins E, A, and B1.
LLLT improves tendon healing through increase of MMP activity and collagen synthesis.
The Achilles tendon has a high incidence of rupture, and the healing process leads to a disorganized extracellular matrix (ECM) with a high rate of injury recurrence. To evaluate the effects of different conditions of low–level laser (LLL) application on partially tenotomized tendons, adult male rats were divided into the following groups: G1, intact; G2, injured; G3, injured + LLL therapy (LLLT; 4 J/cm(2) continuous); G4, injured + LLLT (4 J/cm(2), 20 Hz); G5, injured; G6, injured + LLLT (4 J/cm(2) continuous); and G7, injured + LLLT (4 J/cm(2), 20 Hz until the 7th day and 2 kHz from 8 to 14 days). G2, G3, and G4 were euthanized 8 days after injury, and G5, G6, and G7 were euthanized on the 15th day. The quantification of hydroxyproline (HOPro) and non-collagenous protein (NCP), zymography for matrix metalloproteinase (MMP)-2 and MMP-9, and Western blotting (WB) for collagen types I and III were performed. HOPro levels showed a significant decrease in all groups (except G7) when compared with G1. The NCP level increased in all transected groups. WB for collagen type I showed an increase in G4 and G7. For collagen type III, G4 presented a higher value than G2. Zymography for MMP-2 indicated high values in G4 and G7. MMP-9 increased in both treatment groups euthanized at 8 days, especially in G4. Our results indicate that the pulsed LLLT improved the remodeling of the ECM during the healing process in tendons through activation of MMP-2 and stimulation of collagen synthesis.
LLLT improves tendon healing through increase of MMP activity and collagen synthesis.
Department of Anatomy, Cell Biology and Physiology and Biophysics, Institute of Biology, University of Campinas-UNICAMP, CP 6109, Campinas, São Paulo, 13083-970, Brazil, email@example.com.
The Achilles tendon has a high incidence of rupture, and the healing process leads to a disorganized extracellular matrix (ECM) with a high rate of injury recurrence. To evaluate the effects of different conditions of low-level laser (LLL) application on partially tenotomized tendons, adult male rats were divided into the following groups: G1, intact; G2, injured; G3, injured + LLL therapy (LLLT; 4 J/cm(2) continuous); G4, injured + LLLT (4 J/cm(2), 20 Hz); G5, injured; G6, injured + LLLT (4 J/cm(2) continuous); and G7, injured + LLLT (4 J/cm(2), 20 Hz until the 7th day and 2 kHz from 8 to 14 days). G2, G3, and G4 were euthanized 8 days after injury, and G5, G6, and G7 were euthanized on the 15th day. The quantification of hydroxyproline (HOPro) and non-collagenous protein (NCP), zymography for matrix metalloproteinase (MMP)-2 and MMP-9, and Western blotting (WB) for collagen types I and III were performed. HOPro levels showed a significant decrease in all groups (except G7) when compared with G1. The NCP level increased in all transected groups. WB for collagen type I showed an increase in G4 and G7. For collagen type III, G4 presented a higher value than G2. Zymography for MMP-2 indicated high values in G4 and G7. MMP-9 increased in both treatment groups euthanized at 8 days, especially in G4. Our results indicate that the pulsed LLLT improved the remodeling of the ECM during the healing process in tendons through activation of MMP-2 and stimulation of collagen synthesis.
Management of chronic Achilles tendinopathy.
Tendons transmit force between muscles and bones and, when stretched, store elastic energy that contributes to movement.(1) The tendinous portion of the gastrocnemius and soleus muscles merge to form the Achilles tendon, which is the largest and strongest in the body, but one of the most frequently injured.(2,3) Conservative management options for chronic Achilles tendinopathy include eccentric (lengthening) exercises, extracorporeal shockwave therapy (ESWT), topical nitroglycerin, low level laser therapy, orthoses, splints or injections (e.g. corticosteroids, hyperosmolar dextrose, polidocanol, platelet-rich plasma), while a minority of patients require surgery (using open, percutaneous or endoscopic methods).(4-8) Here we assess the management options for patients with chronic Achilles tendinopathy (lasting over 6 weeks).
Photomed Laser Surg. 2012 Mar;30(3):155-9. Epub 2012 Jan 11.
Effects of a therapeutic laser and passive stretching program for treating tendon overuse.
Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong (SAR), China. Gabriel.Ng@inet.polyu.edu.hk
This study investigated the effects of a therapeutic laser, passive stretching, and their combined treatment on the strength of Achilles tendons with overuse pathologies.
Tendinopathy involving overuse is usually treated with exercise and stretching, but there has been no report on the treatment effect of a therapeutic laser combined with passive stretching on managing this condition. Despite the beneficial effect of a therapeutic laser on healing tendons that have had traumatic injury, its effect on degenerative tendons is not known.
Twenty-five mature Sprague-Dawley (SD) rats were used, with 20 subjected to daily bipedal downhill running for 8 weeks, to induce Achilles overuse, and 5 as normal controls. The exercised rats were divided into four groups: 1, laser treatment; 2, passive stretching; 3, combined laser and stretching; and 4, no treatment, running controls. GaAlAs laser with 660?nm wavelength was applied to both Achilles tendons for 50?sec for Groups 1 and 3. Passive stretching of 20 times/10?sec of maximum ankle plantar flexion was applied to Groups 2 and 3. Treatments were applied after each running session for a a total of 56 treatment sessions. On week 9, the tendons were tested for load-relaxation, stiffness, and ultimate strength.
Stiffness was different (p=0.01), difference in ultimate strength was marginally insignificant (p=0.07), and load-relaxation difference was not significant among groups. Post-hoc analyses revealed that the mean stiffness of all the four exercise groups was lower than the normal control, whereas the ultimate strength from the laser and combined laser and stretching was not different from that of the normal control group, but was higher than that of the passive stretching and no treatment groups.
We conclude that a therapeutic laser and combined laser with passive stretching might slow down the decrease in Achilles tendon strength but would not be able to stop the pathological changes of overuse from developing.
Lasers Med Sci. 2011 Nov 4. [Epub ahead of print]
Effects of low-level laser therapy in combination with physiotherapy in the management of rotator cuff tendinitis.
Physical Medicine and Rehabilitation Research Center, Imam Reza hospital, Tabriz University of Medical Sciences, Golgasht Ave, Tabriz, Iran, firstname.lastname@example.org.
Rotator cuff tendinitis is one of the main causes of shoulder pain. The objective of this study was to evaluate the possible additive effects of low-power laser treatment in combination with conventional physiotherapy endeavors in these patients. A total of 50 patients who were referred to the Physical Medicine and Rehabilitation Clinic with shoulder pain and rotator cuff disorders were selected. Pain severity measured with visual analogue scale (VAS), abduction, and external rotation range of motion in shoulder joint was measured by goniometry, and evaluation of daily functional abilities of patients was measured by shoulder disability questionnaire. Twenty-five of the above patients were randomly assigned into the control group and received only routine physiotherapy. The other 25 patients were assigned into the experimental group and received conventional therapy plus low-level laser therapy (4 J/cm(2) at each point over a maximum of ten painful points of shoulder region for total 5 min duration). The above measurements were assessed at the end of the third week of therapy in each group and the results were analyzed statistically. In both groups, statistically significant improvement was detected in all outcome measures compared to baseline (p?<?0.05). Comparison between two different groups revealed better results for control of pain (reduction in VAS average) and shoulder disability problems in the experimental group versus the control (3.1?±?2.2 vs. 5?±?2.6, p?=?0.029 and 4.4?±?3.1 vs. 8.5?±?5.1, p?=?0.031, respectively ) after intervention. Positive objective signs also had better results in the experimental group, but the mean range of active abduction (144.92?±?31.6 vs. 132.80?±?31.3) and external rotation (78.0?±?19.5 vs. 76.3?±?19.1) had no significant difference between the two groups (p?=?0.20 and 0.77, respectively). As one of physical modalities, gallium-arsenide low-power laser combined with conventional physiotherapy has superiority over routine physiotherapy from the view of decreasing pain and improving the patient’s function, but no additional advantages were detected in increasing shoulder joint range of motion in comparison to other physical agents.
Photomed Laser Surg. 2011 Jun 13. [Epub ahead of print]
Different Power Settings of LLLT on the Repair of the Calcaneal Tendon.
1 Department of Plastic Surgery, Universidade Federal de São Paulo (UNIFESP) , São Paulo, Brazil .
Abstract Objective: The purpose of this study was to evaluate the effect of an 830-nm GaAlAs diode laser operating at output powers of 40, 60, 80, and 100 mW and energy density of 30 J/cm(2) on the repair of partial calcaneal tendon ruptures in rats.
Methods: A partial tendon rupture was induced in all animals, which were treated with laser irradiation for 5 consecutive days. Six days after injury, the injured tendons were removed and examined by polarized light microscopy. Collagen fiber organization was evaluated by birefringence measurements, and collagen content was determined by Picrosirius Red staining.
Results: It was observed that the higher the output power (60-100?mW) the greater the amount of type III collagen (p<0.01). The amount of type I collagen was significantly greater (p=0.05) in the 80 mW group than in the control group (sham stimulation). A non-statistically significant improvement in the realignment of collagen fibers was observed in the irradiated groups.
Conclusions: Low-level laser therapy resulted in significantly greater amounts of type III collagen (output powers of 60 mW or more) and type I collagen (output power of 80 mW), however, no significant differences between groups were found in the realignment of collagen fibers.
Lasers Med Sci. 2011 May 6. [Epub ahead of print]
An experimental study of low-level laser therapy in rat Achilles tendon injury.
Department of Physiotherapy, Faculty of Health and Social Science, Bergen University College, Bergen, Norway, email@example.com
The aim of this controlled animal study was to investigate the effect of low-level laser therapy (LLLT) administered 30 min after injury to the Achilles tendon. The study animals comprised 16 Sprague Dawley male rats divided in two groups. The right Achilles tendons were injured by blunt trauma using a mini guillotine, and were treated with LLLT or placebo LLLT 30 min later. The injury and LLLT procedures were then repeated 15 hours later on the same tendon. One group received active LLLT (??=?904 nm, 60 mW mean output power, 0.158 W/cm(2) for 50 s, energy 3 J) and the other group received placebo LLLT 23 hours after LLLT. Ultrasonographic images were taken to measure the thickness of the right and left Achilles tendons. Animals were then killed, and all Achilles tendons were tested for ultimate tensile strength (UTS). All analyses were performed by blinded observers. There was a significant increase in tendon thickness in the active LLLT group when compared with the placebo group (p?<?0.05) and there were no significant differences between the placebo and uninjured left tendons. There were no significant differences in UTS between laser-treated, placebo-treated and uninjured tendons. Laser irradiation of the Achilles tendon at 0.158 W/cm(2) for 50 s (3 J) administered within the first 30 min after blunt trauma, and repeated after 15 h, appears to lead to edema of the tendon measured 23 hours after LLLT. The guillotine blunt trauma model seems suitable for inflicting tendon injury and measuring the effects of treatment on edema by ultrasonography and UTS. More studies are needed to further refine this model.
Lasers Surg Med. 2010 Aug;42(6):559-65.
Collagen changes and realignment induced by low-level laser therapy and low-intensity ultrasound in the calcaneal tendon.
Wood VT, Pinfildi CE, Neves MA, Parizoto NA, Hochman B, Ferreira LM.
Division of Plastic Surgery, Universidade Federal de São Paulo (UNIFESP), CEP 04023-002 Sao Paulo, SP, Brazil. firstname.lastname@example.org
BACKGROUND AND OBJECTIVE: The treatment of calcaneal tendon injuries requires long-term rehabilitation. Ultrasound (US) and low-level laser therapy (LLLT) are the most used and studied physical agents in the treatment of tendon injuries; however, only a few studies examined the effects of the combination of US and LLLT. Therefore, the purpose of this study was to investigate which treatment (the exclusive or combined use of US and LLLT) most effectively contribute to tendon healing.
STUDY DESIGN/MATERIALS AND METHODS: This was a controlled laboratory study with 50 rats whose Achilles tendon was injured by direct trauma. The rats were randomly divided into five groups and treated for 5 consecutive days, as follows: group 1 (control) received no treatment; group 2 was treated with US alone; group 3 was treated with LLLT alone; group 4 was treated first with US followed by LLLT; and group 5 was treated first with LLLT followed by US. On the sixth post-injury day, the tendons were removed and examined by polarized light microscopy. The organization of collagen fibers was assessed by birefringence measurements. Picrosirius-stained sections were examined for the presence of types I and III collagen.
RESULTS: There was a significantly higher organization of collagen fibers in group 2 (US) than in the control group (P = 0.03). The amount of type I collagen found in groups 2 (US), 3 (LLLT), and 5 (LLLT + US) was significantly higher than that in the control group (P <or= 0.01), but no significant differences were found between treatment groups. There were no differences in the amount of type III collagen between groups.
CONCLUSION: Ultrasound, LLLT, and the combined use of LLLT and US resulted in greater synthesis of type I collagen; US was also effective in increasing collagen organization in the early stages of the healing process.
Photomed Laser Surg. 2010 Aug;28(4):527-32.
Effect of GaAlAs Laser Irradiation on the Epiphyseal Cartilage of Rats.
Cressoni MD, Giusti HH, Pião AC, de Paiva Carvalho RL, Anaruma CA, Casarotto RA.
1 Department of Physiotherapy, University of São Paulo, São Paulo, Brazil.
Abstract Objective: To study the effect of an 830-nm gallium-aluminum-arsenic (GaAlAs) diode laser at two different energy densities (5 and 15 J/cm(2)) on the epiphyseal cartilage of rats by evaluating bone length and the number of chondrocytes and thickness of each zone of the epiphyseal cartilage.
Background Data: Few studies have been conducted on the effects of low-level laser therapy on the epiphyseal cartilage at different irradiation doses. Materials and Methods: A total of 30 male Wistar rats with 23 days of age and weighing 90 g on average were randomly divided into 3 groups: control group (CG, no stimulation), G5 group (energy density, 5 J/cm(2)), and G15 group (energy density, 15 J/cm(2)). Laser treatment sessions were administered every other day for a total of 10 sessions. The animals were killed 24 h after the last treatment session. Histological slides of the epiphyseal cartilage were stained with hematoxylin-eosin (HE), photographed with a Zeiss photomicroscope, and subjected to histometric and histological analyses. Statistical analysis was performed using one-way analysis of variance followed by Tukey’s post hoc test. All statistical tests were performed at a significance level of 0.05.
Results: Histological analysis and x-ray radiographs revealed an increase in thickness of the epiphyseal cartilage and in the number of chondrocytes in the G5 and G15 groups.
Conclusion: The 830-nm GaAlAs diode laser, within the parameters used in this study, induced changes in the thickness of the epiphyseal cartilage and increased the number of chondrocytes, but this was not sufficient to induce changes in bone length.
J Photochem Photobiol B. 2010 Mar 8;98(3):211-5. Epub 2010 Jan 25.
Chondrogenic mRNA expression in prechondrogenic cells after blue laser irradiation.
Kushibiki T, Tajiri T, Ninomiya Y, Awazu K.
Frontier Research Center, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. email@example.com
Low-level laser therapy (LLLT) has been used as a method for biostimulation. Cartilage develops through the differentiation of mesenchymal cells into chondrocytes, and differentiated chondrocytes in articular cartilage maintain cartilage homeostasis by synthesizing cartilage-specific extracellular matrix. The aim of this study is to evaluate the enhancement of chondrocyte differentiation and the expression levels of chondrogenic mRNA in prechondrogenic ATDC5 cells after laser irradiation. For chondrogenic induction, ATDC5 cells were irradiated with a blue laser (405 nm, continuous wave) at 100 mW/cm(2) for 180 s following incubation in chondrogenic differentiation medium. Differentiation after laser irradiation was quantitatively evaluated by the measurement of total collagen contents and chondrogenesis-related mRNAs. The total amount of collagen and mRNA levels of aggrecan, collagen type II, SOX-9, and DEC-1 were increased relative to those of a non-laser irradiated group after 14 days of laser irradiation. On the other hand, Ap-2alpha mRNA, a negative transcription factor of chondrogenesis, was dramatically decreased after laser irradiation. In addition, intracellular reactive oxygen species (ROS) were generated after laser irradiation. These results, for the first time, provide functional evidence that mRNA expression relating to chondrogenesis is increased, and Ap-2alpha is decreased immediately after laser irradiation. As this technique could readily be applied in situ to control the differentiation of cells at an implanted site within the body, this approach may have therapeutic potential for the restoration of damaged or diseased tissue.
Photomed Laser Surg. 2010 Feb;28(1):3-16.
Low level laser treatment of tendinopathy: a systematic review with meta-analysis.
Tumilty S, Munn J, McDonough S, Hurley DA, Basford JR, Baxter GD.
Centre for Physiotherapy Research, School of Physiotherapy, University of Otago, Dunedin, New Zealand. firstname.lastname@example.org
OBJECTIVES: To assess the clinical effectiveness of Low Level Laser Therapy (LLLT) in the treatment of tendinopathy. Secondary objectives were to determine the relevance of irradiation parameters to outcomes, and the validity of current dosage recommendations for the treatment of tendinopathy.
BACKGROUND: LLLT is proposed as a possible treatment for tendon injuries. However, the clinical effectiveness of this modality remains controversial, with limited agreement on the most efficacious dosage and parameter choices.
METHOD: The following databases were searched from inception to 1(st) August 2008: MEDLINE, PubMed, CINAHL, AMED, EMBASE, All EBM reviews, PEDro (Physiotherapy Evidence Database), SCOPUS. Controlled clinical trials evaluating LLLT as a primary intervention for any tendinopathy were included in the review. Methodological quality was classified as: high (> or =6 out of 10 on the PEDro scale) or low (<6) to grade the strength of evidence. Accuracy and clinical appropriateness of treatment parameters were assessed using established recommendations and guidelines.
RESULTS: Twenty-five controlled clinical trials met the inclusion criteria. There were conflicting findings from multiple trials: 12 showed positive effects and 13 were inconclusive or showed no effect. Dosages used in the 12 positive studies would support the existence of an effective dosage window that closely resembled current recommended guidelines. In two instances where pooling of data was possible, LLLT showed a positive effect size; in studies of lateral epicondylitis that scored > or =6 on the PEDro scale, participants’ grip strength was 9.59 kg higher than that of the control group; for participants with Achilles tendinopathy, the effect was 13.6 mm less pain on a 100 mm visual analogue scale.
CONCLUSION: LLLT can potentially be effective in treating tendinopathy when recommended dosages are used. The 12 positive studies provide strong evidence that positive outcomes are associated with the use of current dosage recommendations for the treatment of tendinopathy.
Lasers Surg Med. 2009 Sep;41(7):487-91.
The effects of laser irradiation of cartilage on chondrocyte gene expression and the collagen matrix.
Holden PK, Li C, Da Costa V, Sun CH, Bryant SV, Gardiner DM, Wong BJ.
Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, California 92612, USA.
OBJECTIVES: Laser reshaping of cartilage is an emerging technology aimed at replacing conventional techniques for aesthetic and reconstructive surgery. Little is known about the mechanisms of wound healing following the photothermal heating during laser reshaping and, ultimately, how collagen remodels in the irradiated tissue. Healthy hyaline and elastic cartilage as found in the ear, nose, larynx, and trachea does not express collagen type I which is characteristic of fibro-cartilage and scar tissue. The aim of the study was to determine if collagen I and II gene expression occurs within laser irradiated rabbit septal cartilage.
METHODS: Nasal septum harvested from freshly euthanized New Zealand White rabbits were irradiated with an Nd:YAG laser. After 2 weeks in culture, the laser spot and surrounding non-irradiated regions were imaged using immunofluorescence staining and evaluated using reverse transcription polymerase chain reaction (RT-PCR) to determine the presence of collagen I and II, and ascertain collagen I and II gene expression, respectively.
RESULTS: All laser irradiated specimens showed a cessation in collagen II gene expression within the center of the laser spot. Collagen II was expressed in the surrounding region encircling the laser spot and within the non-irradiated periphery in all specimens. Immunohistochemistry identified only type II collagen. Neither collagen I gene expression nor immunoreactivity were identified in any specimens regardless or irradiation parameters.
CONCLUSIONS: Laser irradiation of rabbit septal cartilage using dosimetry parameters similar to those used in laser reshaping does not result in the detection of either collagen I gene expression or immunoreactivity. Only collagen type II was noted after laser exposure in vitro following cell culture, which suggests that the cellular response to laser irradiation is distinct from that observed in conventional wound healing. Laser irradiation of cartilage can leave an intact collagen matrix which likely allows chondrocyte recovery on an intact scaffold.
Photomed Laser Surg. 2009 Aug 26. [Epub ahead of print]
Low Level Laser Treatment of Tendinopathy: A Systematic Review with Meta-analysis.
Tumilty S, Munn J, McDonough S, Hurley DA, Basford JR, Baxter GD.
1 Centre for Physiotherapy Research, School of Physiotherapy, University of Otago , Dunedin, New Zealand.
Abstract Objectives: To assess the clinical effectiveness of Low Level Laser Therapy (LLLT) in the treatment of tendinopathy. Secondary objectives were to determine the relevance of irradiation parameters to outcomes, and the validity of current dosage recommendations for the treatment of tendinopathy.
Background: LLLT is proposed as a possible treatment for tendon injuries. However, the clinical effectiveness of this modality remains controversial, with limited agreement on the most efficacious dosage and parameter choices. Method: The following databases were searched from inception to 1(st) August 2008: MEDLINE, PubMed, CINAHL, AMED, EMBASE, All EBM reviews, PEDro (Physiotherapy Evidence Database), SCOPUS. Controlled clinical trials evaluating LLLT as a primary intervention for any tendinopathy were included in the review. Methodological quality was classified as: high (>/=6 out of 10 on the PEDro scale) or low (<6) to grade the strength of evidence. Accuracy and clinical appropriateness of treatment parameters were assessed using established recommendations and guidelines.
Results: Twenty-five controlled clinical trials met the inclusion criteria. There were conflicting findings from multiple trials: 12 showed positive effects and 13 were inconclusive or showed no effect. Dosages used in the 12 positive studies would support the existence of an effective dosage window that closely resembled current recommended guidelines. In two instances where pooling of data was possible, LLLT showed a positive effect size; in studies of lateral epicondylitis that scored >/=6 on the PEDro scale, participants’ grip strength was 9.59 kg higher than that of the control group; for participants with Achilles tendinopathy, the effect was 13.6 mm less pain on a 100 mm visual analogue scale.
Conclusion: LLLT can potentially be effective in treating tendinopathy when recommended dosages are used. The 12 positive studies provide strong evidence that positive outcomes are associated with the use of current dosage recommendations for the treatment of tendinopathy
Lasers Med Sci. 2009 Jul;24(4):659-65. Epub 2008 Sep 16.
The effects of low-level light emitting diode on the repair process of Achilles tendon therapy in rats.
Casalechi HL, Nicolau RA, Casalechi VL, Silveira L Jr, De Paula AM, Pacheco MT.
Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraíba, Urbanova, São José dos Campos, São Paulo, Brazil.
Thirty Wistar rats (350 +/- 20 g) were subjected to total Achilles tendon tenotomy of the right fore limb. They were submitted to a daily dose of 20 J/cm(2) light emitting diode (LED) (640 +/- 20 nm) therapy. The LED was applied punctually and transcutaneously to the lesioned region. The animals were separated into six groups, C1 and L1, C2 and L2, C3 and L3. The C groups were used for control and the L groups, treated for 7, 14 and 21 consecutive days, respectively. The animals were killed on the 7th, 14th and 21st days after surgery. After the animals had been killed, their tendons were extracted and dissected, fixed in formaldehyde at 10%, and sent for histological analysis by light microscopy in which the repair process was analysed. This study demonstrated that LED interfered in the repair process of the tendon tissue, reducing the number of fibroblasts in the initial periods and improving the quality of the repair in all periods studied.
Photomed Laser Surg. 2009 Jun;27(3):513-20.
Comparing the effects of exercise program and low-level laser therapy with exercise program and polarized polychromatic non-coherent light (bioptron light) on the treatment of lateral elbow tendinopathy.
Stasinopoulos D, Stasinopoulos I, Pantelis M, Stasinopoulou K.
Rheumatology and Rehabilitation Centre, Athens, Greece. email@example.com
BACKGROUND DATA: The use of low-level laser therapy (LLLT) and polarized polychromatic non-coherent light as supplements to an exercise program has been recommended for the management of lateral elbow tendinopathy (LET).
OBJECTIVE: To investigate whether an exercise program supplemented with LLLT is more successful than an exercise program supplemented with polarized polychromatic non-coherent light in treating LET.
MATERIALS AND METHODS: Patients with unilateral LET for at least 4 wk were sequentially allocated to receive either an exercise program with LLLT or an exercise program with polarized polychromatic non-coherent light. The exercise program consisted of eccentric and static stretching exercises of wrist extensors. In the LLLT group a 904-nm Ga-As laser was used in continuous mode, and the power density was 130 mW/cm(2), and the dose was 0.585 J/point. In the group receiving polarized polychromatic non-coherent light the Bioptron 2 was used to administer the dose perpendicularly to the lateral epicondyle at three points at an operating distance of 5-10 cm for 6 min at each position. The outcome measures were pain and function and were evaluated at baseline, at the end of the treatment (week 4), and 3 mo after the end of treatment (week 16).
RESULTS: Fifty patients met the inclusion criteria. At the end of treatment there was a decline in pain and a rise in function in both groups compared with baseline (p < 0.0005 on the paired t-test). There were no significant differences in the reduction of pain and the improvement of function between the groups at the end of treatment and at the 3-mo follow-up (p > 0.0005 on the independent t-test).
CONCLUSIONS: The results suggest that the combination of an exercise program with LLLT or polarized polychromatic non-coherent light is an adequate treatment for patients with LET. Further research to establish the relative and absolute effectiveness of such a treatment approach is needed.
Lasers Surg Med. 2009 Apr;41(4):271-6.
Effect of low level laser therapy (830 nm) with different therapy regimes on the process of tissue repair in partial lesion calcaneous tendon.
Oliveira FS, Pinfildi CE, Parizoto NA, Liebano RE, Bossini PS, Garcia EB, Ferreira LM.
Department of Plastic Surgery, São Paulo Federal University-UNIFESP, São Paulo, SP 04024-900, Brazil.
BACKGROUND AND OBJECTIVE: Calcaneous tendon is one of the most damaged tendons, and its healing may last from weeks to months to be completed. In the search after speeding tendon repair, low intensity laser therapy has shown favorable effect. To assess the effect of low intensity laser therapy on the process of tissue repair in calcaneous tendon after undergoing a partial lesion.
STUDY DESIGN/MATERIALS AND METHODS: Experimentally controlled randomized single blind study. Sixty male rats were used randomly and were assigned to five groups containing 12 animals each one; 42 out of 60 underwent lesion caused by dropping a 186 g weight over their Achilles tendon from a 20 cm height. In Group 1 (standard control), animals did not suffer the lesion nor underwent laser therapy; in Group 2 (control), animals suffered the lesion but did not undergo laser therapy; in Groups 3, 4, and 5, animals suffered lesion and underwent laser therapy for 3, 5, and 7 days, respectively. Animals which suffered lesion were sacrificed on the 8th day after the lesion and assessed by polarization microscopy to analyze the degree of collagen fibers organization.
RESULTS: Both experimental and standard control Groups presented significant values when compared with the control Groups, and there was no significant difference when Groups 1 and 4 were compared; the same occurred between Groups 3 and 5.
CONCLUSION: Low intensity laser therapy was effective in the improvement of collagen fibers organization of the calcaneous tendon after undergoing a partial lesion.
Clin Orthop Relat Res. 2008 Jul;466(7):1539-54. Epub 2008 Apr 30.
Treatment of tendinopathy: what works, what does not, and what is on the horizon.
Andres BM, Murrell GA.
Orthopaedic Research Institute, St George Hospital, University of New South Wales, Level 2 Research and Education Building, 4-10 South Street, Kogarah, Sydney, NSW, 2217, Australia. firstname.lastname@example.org
Tendinopathy is a broad term encompassing painful conditions occurring in and around tendons in response to overuse. Recent basic science research suggests little or no inflammation is present in these conditions. Thus, traditional treatment modalities aimed at controlling inflammation such as corticosteroid injections and nonsteroidal antiinflammatory medications (NSAIDS) may not be the most effective options. We performed a systematic review of the literature to determine the best treatment options for tendinopathy. We evaluated the effectiveness of NSAIDS, corticosteroid injections, exercise-based physical therapy, physical therapy modalities, shock wave therapy, sclerotherapy, nitric oxide patches, surgery, growth factors, and stem cell treatment. NSAIDS and corticosteroids appear to provide pain relief in the short term, but their effectiveness in the long term has not been demonstrated. We identified inconsistent results with shock wave therapy and physical therapy modalities such as ultrasound, iontophoresis and low-level laser therapy. Current data support the use of eccentric strengthening protocols, sclerotherapy, and nitric oxide patches, but larger, multicenter trials are needed to confirm the early results with these treatments. Preliminary work with growth factors and stem cells is promising, but further study is required in these fields. Surgery remains the last option due to the morbidity and inconsistent outcomes. The ideal treatment for tendinopathy remains unclear. LEVEL OF EVIDENCE: Level II, systematic review.
BMC Musculoskeletal Disorders 2008, 9:75doi:10.1186/1471-2474-9-75
A systematic review with procedural assessments and meta-analysis of Low Level Laser Therapy in lateral elbow tendinopathy (tennis elbow)
Jan M Bjordal , Rodrigo AB Lopes-Martins , Jon Joensen , Anne E Ljunggren , Christian Couppe , Apostolos Stergioulas and Mark I Johnson
|Published:||29 May 2008|
Recent reviews have indicated that low level level laser therapy (LLLT) is ineffective in lateral elbow tendinopathy (LET) without assessing validity of treatment procedures and doses or the influence of prior steroid injections.
Systematic review with meta-analysis, with primary outcome measures of pain relief and/or global improvement and subgroup analyses of methodological quality, wavelengths and treatment procedures.
18 randomised placebo-controlled trials (RCTs) were identified with 13 RCTs (730 patients) meeting the criteria for meta-analysis. 12 RCTs satisfied half or more of the methodological criteria. Publication bias was detected by EggerA’s graphical test, which showed a negative direction of bias. Ten of the trials included patients with poor prognosis caused by failed steroid injections or other treatment failures, or long symptom duration or severe baseline pain. The weighted mean difference (WMD) for pain relief was 10.2 mm [95% CI: 3.0 to 17.5] and the RR for global improvement was 1.36 [1.16 to 1.60]. Trials which targeted acupuncture points reported negative results, as did trials with wavelengths 820, 830 and 1064 nm. In a subgroup of five trials with 904 nm lasers and one trial with 632 nm wavelength where the lateral elbow tendon insertions were directly irradiated, WMD for pain relief was 17.2 mm [95% CI: 8.5 to 25.9] and 14.0 mm [95% CI: 7.4 to 20.6] respectively, while RR for global pain improvement was only reported for 904 nm at 1.53 [95% CI: 1.28 to 1.83]. LLLT doses in this subgroup ranged between 0.5 and 7.2 Joules. Secondary outcome measures of painfree grip strength, pain pressure threshold, sick leave and follow-up data from 3 to 8 weeks after the end of treatment, showed consistently significant results in favour of the same LLLT subgroup (p< 0.02). No serious side-effects were reported.
LLLT administered with optimal doses of 904 nm and possibly 632 nm wavelengths directly to the lateral elbow tendon insertions, seem to offer short-term pain relief and less disability in LET, both alone and in conjunction with an exercise regimen. This finding contradicts the conclusions of previous reviews which failed to assess treatment procedures, wavelengths and optimal doses.
Am J Sports Med. 2008 May;36(5):881-7. Epub 2008 Feb 13.
Effects of low-level laser therapy and eccentric exercises in the treatment of recreational athletes with chronic achilles tendinopathy.
Stergioulas A, Stergioula M, Aarskog R, Lopes-Martins RA, Bjordal JM.
Institute of Physical Therapy, Bergen University College, Mollendalsvn 6, 5009 Bergen, Norway.
BACKGROUND: Eccentric exercises (EEs) are recommended for the treatment of Achilles tendinopathy, but the clinical effect from EE has a slow onset.
HYPOTHESIS: The addition of low-level laser therapy (LLLT) to EE may cause more rapid clinical improvement.
STUDY DESIGN: Randomized controlled trial; Level of evidence, 1.
METHODS: A total of 52 recreational athletes with chronic Achilles tendinopathy symptoms were randomized to groups receiving either EE + LLLT or EE + placebo LLLT over 8 weeks in a blinded manner. Low-level laser therapy (lambda = 820 nm) was administered in 12 sessions by irradiating 6 points along the Achilles tendon with a power density of 60 mW/cm(2) and a total dose of 5.4 J per session.
RESULTS: The results of the intention-to-treat analysis for the primary outcome, pain intensity during physical activity on the 100-mm visual analog scale, were significantly lower in the LLLT group than in the placebo LLLT group, with 53.6 mm versus 71.5 mm (P = .0003) at 4 weeks, 37.3 mm versus 62.8 mm (P = .0002) at 8 weeks, and 33.0 mm versus 53.0 mm (P = .007) at 12 weeks after randomization. Secondary outcomes of morning stiffness, active dorsiflexion, palpation tenderness, and crepitation showed the same pattern in favor of the LLLT group.
CONCLUSION: Low-level laser therapy, with the parameters used in this study, accelerates clinical recovery from chronic Achilles tendinopathy when added to an EE regimen. For the LLLT group, the results at 4 weeks were similar to the placebo LLLT group results after 12 weeks.
Lasers Surg Med. 2008 Mar;40(3):202-10.
Temperature dependent change in equilibrium elastic modulus after thermally induced stress relaxation in porcine septal cartilage.
Protsenko DE, Zemek A, Wong BJ.
Beckman Laser Institute, University of California Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA.
BACKGROUND AND OBJECTIVES: Laser cartilage reshaping (LCR) is a promising method for the in situ treatment of structural deformities in the nasal septum, external ear and trachea. Laser heating leads to changes in cartilage mechanical properties and produces relaxation of internal stress allowing formation of a new stable shape. While some animal and preliminary human studies have demonstrated clinical feasibility of LCR, application of the method outside specialized centers requires a better understanding of the evolution of cartilage mechanical properties with temperature. The purpose of this study was to (1) develop a method for reliable evaluation of mechanical changes in the porcine septal cartilage undergoing stress relaxation during laser heating and (2) model the mechanical changes in cartilage at steady state following laser heating.
STUDY DESIGN/MATERIALS AND METHODS: Rectangular cartilage specimens harvested from porcine septum were heated uniformly by a radio-frequency (RF) electric field (500 kHz) for 8 and 12 seconds to maximum temperatures from 50 to 90 degrees C. Cylindrical samples were fashioned from the heated specimens and their equilibrium elastic modulus was measured in a step unconfined compression experiment. Functional dependencies of the elastic modulus and maximum temperature were interpolated from the measurements. Profiles of the elastic modulus produced after 8 and 12 seconds of laser irradiation (Nd:YAG, lambda = 1.34 microm, spot diameter 4.8 mm, laser power 8 W) were calculated from interpolation functions and surface temperature histories measured with a thermal camera. The calculated elastic modulus profiles were incorporated into a numerical model of uniaxial unconfined compression of laser irradiated cylindrical samples. The reaction force to a 0.1 compressive strain was calculated and compared with the reaction force obtained in analogous mechanical measurements experiment.
RESULTS: RF heating of rectangular cartilage sample produces a spatially uniform temperature field (temperature variations < or = 4 degrees C) in a central region of the sample which is also large enough for reliable mechanical testing. Output power adjustment of the RF generator allows production of temperature histories that are very similar to those produced by laser heating at temperatures above 60 degrees C. This allows creation of RF cartilage samples with mechanical properties similar to laser irradiated cartilage, however with a spatially uniform temperature field. Cartilage equilibrium elastic modulus as a function of peak temperature were obtained from the mechanical testing of RF heated samples. In the temperature interval from 60 to 80 degrees C, the equilibrium modulus decreased from 0.08+/- 0.01 MPa to 0.016+/-0.007 MPa, respectively. The results of the numerical simulation of uniaxial compression of laser heated samples demonstrate good correlation with experimentally obtained reaction force.
CONCLUSIONS: The thermal history and corresponding thermally induced modification of mechanical properties of laser irradiated septal cartilage can be mimicked by heating tissue samples with RF electric current with the added advantage of a uniform temperature profile. The spatial distribution of the mechanical properties obtained in septal cartilage after laser irradiation could be computed from mechanical testing of RF heated samples and used for numerical simulation of LCR procedure. Generalization of this methodology to incorporate orthogonal mechanical properties may aid in optimizing clinical laser cartilage reshaping procedures.
Br J Sports Med. 2006 Jan;40(1):76-80; discussion 76-80.
A randomised, placebo controlled trial of low level laser therapy for activated Achilles tendinitis with microdialysis measurement of peritendinous prostaglandin E2 concentrations.
Bjordal JM, Lopes-Martins RA, Iversen VV.
Physiotherapy Science, University of Bergen, Bergen, Norway. email@example.com
BACKGROUND: Low level laser therapy (LLLT) has gained increasing popularity in the management of tendinopathy and arthritis. Results from in vitro and in vivo studies have suggested that inflammatory modulation is one of several possible biological mechanisms of LLLT action.
OBJECTIVE: To investigate in situ if LLLT has an anti-inflammatory effect on activated tendinitis of the human Achilles tendon.
SUBJECTS: Seven patients with bilateral Achilles tendinitis (14 tendons) who had aggravated symptoms produced by pain inducing activity immediately before the study.
METHOD: Infrared (904 nm wavelength) LLLT (5.4 J per point, power density 20 mW/cm2) and placebo LLLT (0 J) were administered to both Achilles tendons in random blinded order.
RESULTS: Ultrasonography Doppler measurements at baseline showed minor inflammation through increased intratendinous blood flow in all 14 tendons and measurable resistive index in eight tendons of 0.91 (95% confidence interval 0.87 to 0.95). Prostaglandin E2 concentrations were significantly reduced 75, 90, and 105 minutes after active LLLT compared with concentrations before treatment (p = 0.026) and after placebo LLLT (p = 0.009). Pressure pain threshold had increased significantly (p = 0.012) after active LLLT compared with placebo LLLT: the mean difference in the change between the groups was 0.40 kg/cm2 (95% confidence interval 0.10 to 0.70).
CONCLUSION: LLLT at a dose of 5.4 J per point can reduce inflammation and pain in activated Achilles tendinitis. LLLT may therefore have potential in the management of diseases with an inflammatory component.
J Photochem Photobiol B. 2007 Jul 27;88(1):11-5. Epub 2007 May 1.
The therapeutic effect of low-level laser on repair of osteochondral defects in rabbit knee.
Kamali F, Bayat M, Torkaman G, Ebrahimi E, Salavati M.
Department of Physical Therapy, University of Social Welfare and Rehabilitation, Tehran, Iran. firstname.lastname@example.org
INTRODUCTION: Low level laser therapy (LLLT) has been shown to enhance collagen production and wound healing but its effect on cartilage repair from biomechanical point of view is not known yet. The aim of present study was to evaluate the biomechanical behaviour of repairing osteochondral defect in rabbits which received a pulsed low-level gallium-arsenide (Ga-As) laser irradiation.
MATERIALS AND METHODS: Osteochondral defects with 5mm diameter and 4mm in depth induced by drilling in right femoral patellar grooves of 41 adolescent male rabbits. They were divided into experimental and control groups. Experimental group received pulsed Ga-As (890nm) laser irradiation with energy density of 4.8J/cm(2). The rabbits in control group received placebo LLLT with shut-down equipment. The control defects were allowed to heal spontaneously. Each group were divided into three subgroups: A, B and C. Subgroups A, B and C were sacrificed on 4, 8, and 16 weeks after surgery. The knee joint were removed, and the defects were examined biomechanically by in situ-indentation method. The thickness, instantaneous and equilibrium indentation stiffness was measured during the test. Data were analysed using ANOVA and independent sample t-test.
RESULT: While no difference was observed in the repaired cartilage biomechanical properties among 4th, 8th, 16th weeks in study groups. The equilibrium indentation stiffness of experimental group was significantly higher in 8th week in comparison with control group.
CONCLUSION: LLLT significantly enhances the stiffness of repairing tissue in the 8th week post injury in osteochondral defects in rabbits.
Photomed Laser Surg. 2006 Dec;24(6):754-8
Comparative Study Using 685-nm and 830-nm Lasers in the Tissue Repair of Tenotomized Tendons in the Mouse.
- Carrinho PM,
- Renno AC,
- Koeke P,
- Salate AC,
- Parizotto NA,
- Vidal BC.
Laboratory of Electro-Thermo-Phototherapy, Department of Physiotherapy, Federal University of Sao Carlos, Sao Carlos, Brazil.
Objective: The objective of this study was to evaluate the effects of 685- and 830-nm laser irradiations, at different fluences on the healing process of Achilles tendon (Tendon calcaneo) of mice after tenotomy.
Background Data: Some authors have shown that low-level laser therapy (LLLT) is able to accelerate the healing process of tendinuos tissue after an injury, increasing fibroblast cell proliferation and collagen synthesis. However, the mechanism by which LLLT acts on healing process is not fully understood. Methods: Forty-eight male mice were divided into six experimental groups: group A, tenomized animals, treated with 685 nm laser, at the dosage of 3 J/cm(2); group B, tenomized animals, treated with 685-nm laser, at the dosage of 10 J/cm(2); group C, tenomized animals, treated with 830-nm laser, at dosage of 3 J/cm(2); group D, tenomized animals, treated with 830-nm laser, at the dosage of 10 J/cm(2); group E, injured control (placebo treatment); and group F, non-injured standard control. Animals were killed on day 13 post-tenotomy, and their tendons were surgically removed for a quantitative analysis using polarization microscopy, with the purpose of measuring collagen fibers organization through the birefringence (optical retardation [OR]).
Results: All treated groups showed higher values of OR when compared to injured control group. The best organization and aggregation of the collagen bundles were shown by the animals of group A (685 nm, 3 J/cm(2)), followed by the animals of group C and B, and finally, the animals of group D.
Conclusion: All wavelengths and fluences used in this study were efficient at accelerating the healing process of Achilles tendon post-tenotomy, particularly after the 685-nm laser irradiation, at 3 J/cm(2). It suggests the existence of wavelength tissue specificity and dose dependency. Further studies are required to investigate the physiological mechanisms responsible for the effects of laser on tendinuos repair.
Lasers Surg Med. 2005 Jul;37(1):89-96.
Identification of chondrocyte proliferation following laser irradiation, thermal injury, and mechanical trauma.
Wong BJ, Pandhoh N, Truong MT, Diaz S, Chao K, Hou S, Gardiner D.
Beckman Laser Institute and Medical Clinic, University of California-Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA. email@example.com
BACKGROUND AND OBJECTIVE: Cartilage has a limited regenerative capacity, and there are a lack of reliable techniques and methods to stimulate growth of new tissue to treat degenerative diseases and trauma. This study focused on identifying chondrocyte cell proliferation in ex vivo cartilage tissue following heating Nd:YAG laser using whole-mount analysis and flow cytometry, and compared findings with results produced by contact, and water bath heating methods, mechanical injury, and the addition of transforming growth factor-beta (TGF-beta).
STUDY DESIGN/MATERIALS AND METHODS: Ex vivo rabbit nasal septal cartilages were either irradiated with an Nd:YAG laser (lambda = 1.32 microm, 2-16 seconds, 6 W/cm(2)), heated by immersion in a warm saline bath, heated by direct contact with a metal rod, or mechanically damaged by scoring with a scalpel or crushing. After treatment, specimens were incubated for 7 or 14 days in growth media containing 10 microM bromodeoxyuridine (BrdU). Additional specimens were cultured with both BrdU and TGF-beta. Both whole-mount BrdU-double-antibody detection techniques and flow cytometry were used to determine the presence of DNA replication as a marker of proliferation.
RESULT: An annular region of regenerating chondrocytes was identified surrounding the laser irradiation zone in whole-mount tissue specimens, and the diameter of this region increased with irradiation time. Using whole-mount analysis, no evidence of chondrocyte DNA replication was observed in tissues heated using non-laser methods, grown in TGF-beta, or mechanically traumatized. In contrast, flow cytometry identified the presence of BrdU-positive cells in the S-phase of the cell cycle (synthesis of DNA) for all protocols, indicating chondrocyte proliferation. The percentage of cells that are in S-phase increased with irradiation time.
CONCLUSION: These data provide evidence that laser irradiation, along with other thermal and mechanical treatments, causes a proliferative response in chondrocytes, and this is observed ex vivo in the absence of cellular and humoral repair mechanisms. The advantage of using optical methods to generate heat in cartilage is that microspot injuries could be created in tissue and scanned across surfaces in clinical applications.
Lasers Surg Med. 2005 Oct;37(4):293-300
Low-level laser therapy (LLLT) prevents oxidative stress and reduces fibrosis in rat traumatized Achilles tendon.
Fillipin LI, Mauriz JL, Vedovelli K, Moreira AJ, Zettler CG, Lech O, Marroni NP, González-Gallego J.
Department of Physiology, Universidade Federal de Rio Grande do Sul, Brazil.
BACKGROUND AND OBJECTIVES: The present study investigated the effects of low-level laser therapy (LLLT) on oxidative stress and fibrosis in an experimental model of Achilles tendon injury induced by a single impact trauma.
STUDY DESIGN/MATERIALS AND METHODS: Male Wistar rats were randomly divided into four groups (n = 8): control, trauma, trauma+LLLT for 14 days, and trauma+LLLT for 21 days. Achilles tendon traumatism was produced by dropping down a load with an impact kinetic energy of 0.544 J. A low level Ga-As laser was applied with a 904 nm wavelength, 45 mW average power, 5 J/cm(2) dosage, for 35 seconds duration, continuously. Studies were carried out at day 21.
RESULTS: Histology showed a loss of normal architecture, with inflammatory reaction, angiogenesis, vasodilatation, and extracellular matrix formation after trauma. This was accompanied by a significant increase in collagen concentration when compared the control group. Oxidative stress, measured by the concentration of thiobarbituric acid reactive substances and hydroperoxyde-initiated chemiluminiscence, was also significantly increased in the trauma group. Administration of LLLT for 14 or 21 days markedly alleviated histological abnormalities reduced collagen concentration and prevented oxidative stress. Superoxide dismutase activity was significantly increased by LLLT treatment over control values.
CONCLUSION: LLLT by Ga-As laser reduces histological abnormalities, collagen concentration, and oxidative stress in an experimental model of Achilles tendon injury. Reduction of fibrosis could be mediated by the beneficial effects on the oxidant/antioxidant balance.
Photomed Laser Surg. 2004 Aug;22(4):323-9.
The efficacy of low-power lasers in tissue repair and pain control: a meta-analysis study.
Enwemeka CS, Parker JC, Dowdy DS, Harkness EE, Sanford LE, Woodruff LD.
School of Health Professions, Behavioral and Life Sciences, New York Institute of Technology, Old Westbury, NY 11568-8000, USA. Enwemeka@nyit.edu
OBJECTIVE: We used statistical meta-analysis to determine the overall treatment effects of laser phototherapy on tissue repair and pain relief.
BACKGROUND DATA: Low-power laser devices were first used as a form of therapy more than 30 years ago. However, their efficacy in reducing pain or promoting tissue repair remains questionable.
METHODS: Following a literature search, studies meeting our inclusion criteria were identified and coded. Then, the effect size of laser treatment, that is, Cohen’s d, was calculated from each study using standard meta-analysis procedures.
RESULTS: Thirty-four peer-reviewed papers on tissue repair met our inclusion criteria and were used to calculate 46 treatment effect sizes. Nine peer-reviewed papers on pain control met the inclusion criteria and were used to calculate nine effect sizes. Meta-analysis revealed a positive effect of laser phototherapy on tissue repair (d = +1.81; n = 46) and pain control (d = +1.11; n = 9). The positive effect of treatment on specific indices of tissue repair was evident in the treatment effect sizes determined as follows: collagen formation (d = +2.78), rate of healing (d = +1.57), tensile strength (d = +2.13), time needed for wound closure (d = +0.76), tensile stress (d = +2.65), number and rate of degranulation of mast cells (d = +1.87), and flap survival (d = +1.95). Further, analysis revealed the positive effects of various wavelengths of laser light on tissue repair, with 632.8 nm having the highest treatment effect (d = +2.44) and 780 nm the least (d = 0.60). The overall treatment effect for pain control was positive as well (d = +1.11). The fail-safe number-that is, the number of studies in which laser phototherapy has negative or no effect-needed to nullify the overall outcome of this analysis was 370 for tissue repair and 41 for pain control.
CONCLUSIONS: These findings mandate the conclusion that laser phototherapy is a highly effective therapeutic armamentarium for tissue repair and pain relief.
Lasers Surg Med. 2004;34(4):323-8.
Effect of low-power He-Ne laser irradiation on rabbit articular chondrocytes in vitro.
Jia YL, Guo ZY.
Institute of Laser Life Science, South China Normal University, Guangzhou, GD 510631, China.
- Lasers Surg Med. 2005 Oct;37(4):330.
BACKGROUND AND OBJECTIVES: In the orthopaedic field, the repair of articular cartilage is still a difficult problem, because of the physiological characters of cartilaginous tissues and chondrocytes. To find an effective method of stimulating their regeneration, this in vitro study focuses on the biostimulation of rabbit articular chondrocytes by low-power He-Ne laser.
STUDY DESIGN/MATERIALS AND METHODS: The articular chondrocytes isolated from the cartilage of the medial condyle of the femur of the rabbit were incubated in DMEM/HamF(12) medium. The second passage culture were spread on 24 petri dishes and were irradiated with laser at power output of 2-12 mW for 6.5 minutes, corresponding to the energy density of 1-6 J/cm(2). Laser treatment was performed three times at a 24-hour interval. After lasering, incubation was continued for 24 hours. Non-irradiated cells were kept under the same conditions as the irradiated ones. The cell proliferation activity was evaluated with a XTT colorimetric method and the cell secretion activity was analyzed by metachromasia and immunocytochemistry.
RESULTS: Irradiation of 4-6 J/cm(2) increased the cell numbers and revealed a considerably higher cell proliferation activity comparing to control cultures. Thereinto, the energy density of 4 and 5 J/cm(2) remarkably increased cell growth, with positive effect on synthesis and secretion of extracellular matrix.
CONCLUSIONS: The present study showed that a particular laser irradiation stimulates articular chondrocytes proliferation and secretion. These findings might be clinically relevant, indicating that low-power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.
Indian J Exp Biol. 2004 Sep;42(9):866-70.
Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits.
Bayat M, Ansari A, Hekmat H.
Anatomy Department and Cell and Molecular Research Center, Medical Faculty, Shaheed Beheshti University of Medical Sciences, Tehran, Iran. firstname.lastname@example.org
Influence of low-power (632.8 nm, Helium-Neon, 13 J/cm2, three times a week) laser on 13-week immobilized articular cartilage was examined with rabbits knee model. Number of chondrocytes and depth of articular cartilage of experimental group were significantly higher than those of sham irradiated group. Surface morphology of sham-irradiated group had rough prominences, fibrillation and lacunae but surface morphology of experimental group had more similarities to control group than to sham irradiated group. There were marked differences between ultrastructure features of control group and experimental group in comparison with sham irradiated group. Low-power Helium-Neon laser irradiation on 13-week immobilized knee joints of rabbits neutrilized adverse effects of immobilization on articular cartilage.
Lasers Surg Med. 2004;35(1):84-9.
Comparison of the effects of laser, ultrasound, and combined laser + ultrasound treatments in experimental tendon healing.
Demir H, Menku P, Kirnap M, Calis M, Ikizceli I.
Erciyes University Medical Faculty, Department of Physical Medicine & Rehabilitation, Kayseri, Turkey. email@example.com
BACKGROUND AND OBJECTIVE: Therapeutic ultrasound (US) and laser (L) treatments accelerate and facilitate wound healing, and also have beneficial effects on tendon healing. This randomized control study was designed to evaluate the effects of low-intensity US and low-level laser therapy (LLLT) on tendon healing in rats.
STUDY DESIGN/MATERIALS AND METHODS: Eighty-four healthy male Swiss-Albino rats were divided into three groups consisting of 28 rats, the left Achilles tendons were used as treatment and the right Achilles tendons as controls. The right and left Achilles tendons of rats were traumatized longitudinally. The treatment was started on postinjury day one. We applied the treatment protocols including low-intensity US treatment in Group I (US Group), Sham US in Group II (SUS Group), LLLT in Group III (L Group), Sham L in Group IV (SL Group), US and LLLT in Group V (US + L Group), and Sham US and Sham L in Group VI (SUS + SL Group). The US treatment was applied with a power of 0.5 W/cm2, a frequency of 1 MHz, continuously, 5 minutes daily. A low-level Ga-As laser was applied with a 904 nm wavelength, 6 mW average power, 1 J/ cm2 dosage, 16 Hz frequency, for 1 minute duration, continuously. In the control groups, the similar procedures as in the corresponding treatment groups were applied with no current (Sham method). The treatment duration was planned for 9 days (sessions) in all groups, except the rats used for biochemical evaluation on the 4th day of treatment, which were treated for 4 days. We measured the levels of the tissue hydroxyproline for biochemical evaluation on the 4th, 10th, and 21st days following the beginning of treatment and the tendon breaking strength on the 21st day following the beginning of treatment for biomechanical evaluation. Seven rats in each group were killed on the 4th, 10th, and 21st days for biochemical evaluation and on the 21st day for biomechanical evaluation.
RESULTS: The hydroxyproline levels were found to be significantly increased in the treatment groups on the 10th and 21st days compared to their control groups (P < 0.05). In comparison of the treatment groups on the 4th, 10th, and 21st days of the treatment, the levels of tissue hydroxyproline were found to be more increased in combined US+L Group compared with US Group and L Group, but the difference was not significant (P > 0.05). In comparison of the tendon breaking strengths, it was found as significantly increased in the treatment groups compared with their control groups (P < 0.05), although there was no significant difference between the treatment groups.
CONCLUSIONS: Although US, L, and combined US + L treatments increased tendon healing biochemically and biomechanically more than the control groups, no statistically significant difference was found between them. Also we did not find significantly more cumulative positive effects of combined treatment. As a result, both of these physical modalities can be used successfully in the treatment of tendon healing.
Lasers Surg Med. 2003;32(1):3-9.
Quantitative assessment of chondrocyte viability after laser mediated reshaping: a novel application of flow cytometry.
Rasouli A, Sun CH, Basu R, Wong BJ.
Beckman Laser Institute and Medical Clinic, University of California Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA.
BACKGROUND AND OBJECTIVES: Lasers can be used to reshape cartilage by accelerating mechanical stress relaxation. In this study, fluorescent differential cell viability staining and flow cytometry were used to determine chondrocyte viability following laser heating.
STUDY DESIGN/MATERIALS AND METHODS: Porcine septal cartilages were irradiated with an Nd:YAG laser (lambda = 1.32 microm, 25 W/cm(2)) while surface temperature, stress relaxation, and diffuse reflectance were recorded. Each slab received one, two, or three laser exposures (respective exposure times of 6.7, 7.2, 10 seconds). Irradiated samples were then divided into two groups analyzed immediately and at 5 days following laser exposure. Chondrocytes were isolated following serial enzymatic digestion, and stained using SYTO/DEAD Red (Molecular Probes, Eugene, OR). A flow cytometer was then used to detect differential cell fluorescence; size; granularity; and the number of live cells, dead cells, and post-irradiation debris in each treatment population.
RESULTS: Nearly 60% of chondrocytes from reshaped cartilage samples isolated shortly after one irradiation, were viable while non-irradiated controls were 100% viable. Specimens irradiated two or three times demonstrated increasing amounts of cellular debris along with a reduction in chondrocyte viability: 31 and 16% after two and three exposures, respectively. In those samples maintained in culture medium and assayed 5 days after irradiation, viability was reduced by 28-88%, with the least amount of deterioration in untreated and singly irradiated samples.
CONCLUSIONS: Functional fluorescent dyes combined with flow cytometric analysis successfully determines the effect of laser irradiation on the viability of reshaped cartilage.
|Lasers Surg Med. 2003;32(4):286-93.|
THE INFLUENCE OF LOW LEVEL INFRA RED LASER THERAPY ON THE REGENERATION OF CARTILAGE TISSUE
P.Lievens , Ph.van der Veen
This study concerns the influence of Laser treatment on the regeneration process of cartilage tissue. There is no need saying that the regeneration of cartilage tissue is a very big problem in rheumatic diseases for example. The lack of blood supply is one of the most important factors involved. Lots of previous publications give us proof of the regeneration capacities of Laser therapy (in wound healing, bone repair etc.)
In this study we have chosen to experiment on cartilage tissue of the ear of mice. We are aware of the fact that the elastic cartilage tissue of the ear is not totally comparable with the hyaline cartilage of articulations. For technical reasons however and because of the fact that the chondrocytes are comparable, we decided to use mice ears in our experiment. A 0,4 mm hole was drilled in both ears on 30 mice. The right ears remain untreated, while the left ears were treated daily with IR-Laser (904 nm) for 3 minutes. Macroscopical as well as histological evaluations were performed on the cartilage regeneration of both ears.
Our results show that after one day postsurgery no differences were found between the irradiated and the non-irradiated group. After the second day, only in the irradiated group there is a clear activation of the perichondrium. After four days, there is a significant ingrowth of the perichondrium into the drill hole in the experimental group and there is only an active perichondrium zone in our control group.
Lasers Surg Med. 2002; 31: 263-267.
Effect of low-power laser irradiation on cell growth and procollagen synthesis of cultured fibroblasts.
Pereira A, de Paula Eduardo C, Matson E et al
The cell growth and procollagen synthesis of cultured fibroblasts were studies by irradiation at energy densitites ranging from 3-5 J/cm2 over a period of 6 days. To simulate a situation of stress the cells were grown in a 2.5% FBS solution (10% being optimal). The laser was a 120 mW GaAs laser. Irradiation at 3 to 4 J/cm2 increased the cell numbers about threefold to sixfold, compared to control cultures. However, the effect was restricted to a small range of densities, since 5 J/cm2 had no effect on cell growth. The energy density of 3 J/cm2 remarkably increased cell growth, with no effect on procollagen synthesis, as demonstrated by immunoprecipitation analysis.
Biomed Pharmacother. 2001 Mar;55(2):117-20.
Laser biostimulation of cartilage: in vitro evaluation.
Torricelli P, Giavaresi G, Fini M, Guzzardella GA, Morrone G, Carpi A, Giardino R.
Experimental Surgery Department, Istituto di Ricerca Codivilla-Putti, Bologna, Italy. paolapaola..firstname.lastname@example.org
An in vitro study was performed to evaluate the laser biostimulation effect on cartilage using a new gallium-aluminium-arsenic diode laser. Chondrocyte cultures were derived from rabbit and human cartilage. These cells were exposed to laser treatment for 5 days, using the following parameters: 300 joules, 1 watt, 100 (treatment A) or 300 (treatment B) hertz, pulsating emission for 10 minutes, under a sterile laminar flow. Control cultures (no treatment) received the same treatment with the laser device off. Cell viability was measured by MTT assay at the end of the laser treatment and then after 5 days. Neither rabbit nor human cultured chondrocytes showed any damage under a light microscope and immunostaining control following laser treatment. The MTT test results indicated a positive biostimulation effect on cell proliferation with respect to the control group. The increase in viability of irradiated chondrocytes was maintained for five days following the end of the laser treatment. The results obtained with the Ga-Al-As diode laser using the above tested parameters for in vitro biostimulation of cartilage tissues provide a basis for a rational approach to the experimental and clinical use of this device.
Lasers Surg Med. 2001;28(1):1-10.
Laser-mediated cartilage reshaping with feedback-controlled cryogen spray cooling: biophysical properties and viability.
Karamzadeh AM, Rasouli A, Tanenbaum BS, Milner TE, Nelson JS, Wong BJ.
Beckman Laser Institute and Medical Clinic, University of California Irvine, 92697, USA.
BACKGROUND AND OBJECTIVE: Recent studies have indicated that chondrocyte viability decreases with prolonged or repeated laser irradiation. To optimize laser-mediated cartilage reshaping, the heating process must be finely controlled. In this study, we use high-power Nd:YAG laser irradiation (lambda = 1.32 microm) combined with cryogen spray cooling (CSC) in an attempt to reshape porcine septal cartilage while enhancing chondrocyte viability.
STUDY DESIGN/MATERIALS AND METHODS: Chondrocyte viability was determined after high-power (50 W/cm2) Nd:YAG-mediated cartilage reshaping with and without cryogen spray cooling (CSC) and correlated with dynamic measurements of tissue optical and thermal properties.
RESULTS: After 1.5 to 2.0 seconds of laser exposure, characteristic changes in diffuse reflectance (indicating the onset of accelerated stress relaxation) was observed in both laser only and laser with CSC specimens. After 2 seconds of laser exposure, specimens in both groups retained the curved shape for up to 14 days. After one laser exposure, chondrocyte viability was 94.35 +/- 6.1% with CSC and 68.77 +/- 20.1% (P < 0.05) without CSC. After two laser exposures, a similar trend was observed with CSC (70.18 +/- 16.44%) opposed to without CSC (28 +/- 45%; P < 0.05).
CONCLUSION: CSC during high-power laser irradiation allows rapid heating while minimizing extreme front surface temperature elevations and axial thermal gradients. Laser irradiation with CSC can be used to effectively reshape cartilage tissue with the additional advantage of increasing chondrocyte viability.
Artif Cells Blood Substit Immobil Biotechnol. 2000 Mar;28(2):193-201.
Biostimulation of human chondrocytes with Ga-Al-As diode laser: ‘in vitro’ research.
Morrone G, Guzzardella GA, Tigani D, Torricelli P, Fini M, Giardino R.
Department of Experimental Surgery, Rizzoli Orthopaedic Institute Bologna, Italy.
The aim of this study was to verify the effects of laser therapy performed with Ga-Al-As Diode Lasers (780 nm, 2500 mW) on human cartilage cells in vitro. The cartilage sample used for the biostimulation treatment was taken from the right knee of a 19-year-old patient. After the chondrocytes were isolated and suspended for cultivation, the cultures were incubated for 10 days. The cultures were divided into four groups. Groups I, II, III were subject to biostimulation with the following laser parameters: 300 J, 1 W, 100 Hz, 10 min. exposure, pulsating emission; 300 J, 1 W, 300 Hz, 10 min. exposure, pulsating emission; and 300 J, 1 W, 500 Hz, 10 min. exposure, pulsating emission, respectively. Group IV did not receive any treatment. The laser biostimulation was conducted for five consecutive days. At the end of the treatment, the Calcium, Alkaline Phosphate, MTT tests and proteoglycan were performed to assess cell metabolism and toxicity level. The data showed good results in terms of cell viability and levels of Ca and Alkaline Phosphate in the groups treated with laser biostimulation compared to the untreated group. The results obtained confirm our previous positive in vitro results that the Ga-Al-As Laser provides biostimulation without cell damage.
Photochem Photobiol. 2000 Feb;71(2):218-24.
Proteoglycan synthesis in porcine nasal cartilage grafts following Nd:YAG (lambda = 1.32 microns) laser-mediated reshaping.
Wong BJ, Milner TE, Kim HK, Chao K, Sun CH, Sobol EN, Nelson JS.
Beckman Laser Institute and Medical Clinic, University of California, Irvine 92612, USA. email@example.com
Mechanically deformed morphologic cartilage grafts undergo temperature-dependent stress relaxation during sustained laser irradiation resulting in stable shape changes. In this study, porcine nasal septal cartilage specimens were evaluated for viability by measuring the incorporation of Na2(35)SO4 into proteoglycan (PTG) macromolecules in whole tissue culture following laser-mediated reshaping. Synthesis rates of PTG were determined by scintillation counting lyophilized specimens and normalizing these values by total protein content. Positive controls were established by inducing chondrocyte apoptosis using prolonged exposure to nitric oxide (NO). In chondrocytes, apoptosis induced using NO resulted in significantly lower PTG synthesis rates compared to untreated native specimens. Cartilage specimens were irradiated with light emitted from a Nd:YAG laser (25 W/cm2, lambda = 1.32 microns) while recording simultaneously radiometric surface temperature, internal stress and back-scattered light intensity from a probe laser. Each specimen received one, two or three sequential laser exposures. The duration of each exposure was determined from real-time measurements of characteristic changes in back-scattered light intensity that correlate with accelerated stress relaxation. A 5 min time interval between each laser exposures allowed the cartilage specimen to return to thermal equilibrium. Average PTG synthesis rates decreased with successive laser exposures, though these were always higher than baseline rates established for NO-treated tissues, suggesting that laser-mediated cartilage reshaping acutely does not eliminate the entire population of viable chondrocytes. The reduction in PTG synthesis is correlated with the time-temperature-dependent heating profile created during laser irradiation, supporting our hypothesis that careful monitoring of laser dosimetry is required to ensure chondrocyte viability.
Acta Biomed Ateneo Parmense. 1999;70(3-4):43-7.
Cartilage cell stimulation with low-power laser: experimental assessment.
[Article in Italian]
Guzzardella GA, Torricelli P, Fini M, Morrone G, Giardino R.
Servizio di Chirurgia Sperimentale Istituto di Ricerca Codivilla-Putti-I.O.R. Cattedra di Fisiopatologia Chirurgica, Facoltà di Medicina e Chirurgia, Università di Bologna.
The aim of this study was to verify the effects of laser therapy performed with Ga-Al-As diode laser (780 nm, 2500 mW) on cartilage cells in vitro. The cartilage sample used for biostimulation was taken from the knee of an adult patient. The cultures were divided into four groups: Groups I, II, III were subjected to biostimulation with different laser parameters; Group IV did not received any treatment. The laser biostimulation was conducted for five consecutive days. At the end of the treatment, cell count and MTT tests were performed to assess cell metabolism. The data showed good results in terms of cell viability in the groups treated with laser biostimulation compared to the untreated group. The results obtained with the use of this new low-power diode laser Ga-Al-As device in the biostimulation of the cartilage tissue, permits us to consider the use of this device clinically.
Wound Repair Regen. 1999 Nov-Dec;7(6):518-27.
Matrix remodeling in healing rabbit Achilles tendon.
Reddy GK, Stehno-Bittel L, Enwemeka CS.
Department of Physical Therapy, University of Kansas Medical Center, Kansas City 66160-4568, USA. firstname.lastname@example.org
Biochemical, biomechanical and ultrastructural properties of the connective tissue matrix were investigated during the early remodeling phase of tissue repair in experimentally tenotomized and repaired rabbit Achilles tendons. Sterile surgical tenotomy was performed on the right Achilles tendons of 14 rabbits and allowed to heal for 15 days. The animals were euthanized and the Achilles tendons excised from both limbs. The left contralateral Achilles tendon of each rabbit was used as a control in the experiments. Prior to biochemical analysis, both intact and healing tendons were tested for their biomechanical integrity. The results revealed that the healing tendons had regained some of their physicochemical characteristics, but differed significantly from the intact left tendons. The healing tendons regained 48% tensile strength, 30% energy absorption, 20% tensile stress, and 14% Young’s modulus of elasticity of intact tendons. In contrast, biochemical analysis showed that the healing tendons had 80% of the collagen and 60% of the collagen crosslinks (hydroxypyridinium) of normal tendons. Sequential extraction of collagen from the tissues yielded more soluble collagen in the healing tendons than intact tendons, suggesting either an increase in collagen synthesis and/or enhanced resorption of mature collagen in healing tendons compared to intact tendons. Electron microscopic studies revealed remarkable differences in the ultrastructure between intact and healing tendons. These observations could explain, in part, the connective tissue response to healing during the early phases of tissue remodeling.
Artif Cells Blood Substit Immobil Biotechnol. 1998 Jul;26(4):437-9.
In vitro experimental research of rabbit condrocytes biostimulation with diode laser Ga-Al-As: a preliminary study.
Morrone G, Guzzardella GA, Torricelli P, Fini M, Giardino R.
Department of Experimental Surgery, Istituto di Ricerca Codivilla-Putti/Rizzoli Orthopedic Institutes, Bologna, Italy.
The scope of our study was to verify the effects of a new diode laser device with active material composed of Gallium, Aluminum and Arsenic (Ga-Al-As) configured as MOCVD (780 nm., 3000 mW) for the biostimulation of the cartilage cells in vitro. The condrocytes cells, withdrawn from the cartilage of the medial condyle of the femur of the rabbit, were cultivated, incubated and subject to biostimulation treatment with the laser. The condrocytes cells were placed in 24 Petri dishes at the concentration of 0.25 x 10(5)/ml and divided into 4 groups: 3 group (I, II, III) were treated with the laser and the fourth group (IV) was used as the control group. At the end of the treatment, all four groups, were evaluated with a MTT test and a cell count of the condrocytes cells. Group III (300 J, 1 Watt, 300 Hz, 10′ of exposure time with a pulsating emission) provided the best results in terms of cell viability (MTT test) and for the number of cells found in the dishes when compared to the other treated groups and the control group. The results obtained with the use of this new diode laser Ga-Al-As device in the biostimulation of the cartilage tissue, permits us to consider the use of this device clinically.
Med Sci Sports Exerc. 1998 Jun;30(6):794-800.
Biochemistry and biomechanics of healing tendon: Part II. Effects of combined laser therapy and electrical stimulation.
Reddy GK, Gum S, Stehno-Bittel L, Enwemeka CS.
Department of Physical Therapy, University of Kansas Medical Center, Kansas City 66160-7601, USA.
PURPOSE: In previous studies we demonstrated that early mechanical loading and laser photo-stimulation independently promoted tendon healing. Thus, we tested the hypothesis that a combination of laser phototherapy and mechanical load would further accelerate healing of experimentally tenotomized and repaired rabbit Achilles tendons.
METHODS: Following surgical tenotomy and repair, the tendons of experimental and control rabbits were immobilized in polyurethane casts for 5 d. The repaired tendons of experimental rabbits received mechanical load via electrical stimulation-induced contraction of the triceps surae for 5 d. In addition, experimental tendons were treated with daily doses of 1 J.cm-2 low intensity helium-neon laser throughout the 14-d experimental period.
RESULTS: The combination of laser photostimulation and mechanical load increased the maximal stress, maximal strain, and Young’s modulus of elasticity of the tendons 30, 13, and 33%, respectively. However, MANOVA revealed no statistically significant differences in these biomechanical indices of repair of control and experimental tendons. Biochemical assays showed a 32% increase in collagen levels (P < 0.05) and an 11% decrease in mature cross-links in experimental tendons compared with that in controls (P > 0.05). Electron microscopy and computer morphometry revealed no significant differences in the morphometry of the collagen fibers and no visible differences in the ultrastructure of cellular and matrical components of control and experimental tendons.
CONCLUSIONS: These findings indicate that the combination of laser photostimulation and early mechanical loading of tendons increased collagen production, with marginal biomechanical effects on repaired tendons.
Lasers Surg Med. 1998;22(5):281-7.
Laser photostimulation of collagen production in healing rabbit Achilles tendons.
Reddy GK, Stehno-Bittel L, Enwemeka CS.
Department of Physical Therapy, University of Kansas Medical Center, Kansas City 66160-7601, USA.
BACKGROUND AND OBJECTIVE: Low energy laser photostimulation at certain wavelengths can enhance tissue repair by releasing growth factors from fibroblasts and stimulate the healing process. This study was designed to evaluate the influence of laser photostimulation on collagen production in experimentally tenotomized and repaired rabbit Achilles tendons.
STUDY DESIGN/MATERIALS AND METHODS: A total of 24 male New Zealand rabbits, ages 10-12 weeks, were used. Following tenotomy and repair, the surgical hind limbs of the rabbits were immobilized in customized polyurethane casts. The experimental animals were treated with a 632.8 nm He:Ne laser daily at 1.0 J cm(-2) for 14 days. Control animals were sham treated with the laser head. On the fifth day after repair, the casts were removed to allow the animals to bear weight on the lower extremity. The animals were euthanized on the 15th postoperative day, then, the Achilles tendons were excised, processed and analyzed.
RESULTS: Biochemical analyses of the tendons revealed a 26% increase in collagen concentration with laser photostimulation indicating a more rapid healing process in treated tendons compared to controls. Sequential extractions of collagen from regenerating tissues revealed that the laser photostimulated tendons had 32% and 33% greater concentrations of neutral salt soluble collagen and insoluble collagen, respectively, than control tendons suggesting an accelerated production of collagen with laser photostimulation. A significant decrease (9%) in pepsin soluble collagen was observed in laser-treated tendons compared to controls. There were no statistically significant differences recorded in the concentrations of hydroxypyridinium crosslinks and acid soluble collagen between treated and control tendons.
CONCLUSION: This study of laser photostimulation on tendon healing in rabbits suggests that such therapy facilitates collagen production in a manner that enhances tendon healing.
Am J Phys Med Rehabil. 1997 Jul-Aug;76(4):288-96.
Combined ultrasound, electrical stimulation, and laser promote collagen synthesis with moderate changes in tendon biomechanics.
Gum SL, Reddy GK, Stehno-Bittel L, Enwemeka CS.
Department of Physical Therapy, University of Kansas Medical Center, Kansas City 66160-7601, USA.
The biomechanical, biochemical, and ultrastructural effects of a multitherapeutic protocol were studied using regenerating rabbit Achilles tendons. The multitherapeutic protocol was composed of low-intensity Ga:As laser photostimulation, low intensity ultrasound, and electrical stimulation. Achilles tendons of 63 male New Zealand rabbits were tenotomized, sutured, immobilized, and subjected to the multitherapeutic protocol for five days, after which casts were removed and the therapy was continued for nine more days without electrical stimulation. The tendons were excised and compared with control tendons. Multitherapy treatment produced a 14% increase in maximal strength, a 42% increase in load-at-break, a 20% increase in maximal stress, a 45% increase in stress-at-break, a 21% increase in maximal strain, and a 14% increase in strain-at-break. Similarly, multitherapy treatment was associated with an increase in Young’s modulus of elasticity of 31%, an increase in energy absorption at maximum load of 9%, and an increase in energy absorption at load-at-break of 11%. Biochemical analysis of the tendons showed an increase of 23% in the total amount of collagen in the multitherapy-treated tendons, with fewer mature crosslinks (decrease of 6%). Electron micrographs revealed no ultrastructural or morphologic changes in the tendon fibroblasts or in the extracellular matrix. The improvements measured in tendons receiving multitherapy were consistent but less remarkable compared with our earlier works with single modality protocols. The results warrant the hypothesis that the beneficial effects of ultrasound and laser photostimulation on tendon healing may counteract one another when applied simultaneously.
|Lasers Surg Med. 1997;21(5):480-4.|
Laser’s effect on bone and cartilage change induced by joint immobilization: an experiment with animal model.
Akai M, Usuba M, Maeshima T, Shirasaki Y, Yasuoka S.Department of Physical Therapy,
Tsukuba College of Technology, Ibaraki, Japan. email@example.com
OBJECTIVE: Influence of low-level (810 nm, Ga-Al-As semiconductor) laser on bone and cartilage during joint immobilization was examined with rats’ knee model.
MATERIALS AND METHODS: The hind limbs of 42 young Wistar rats were operated on in order to immobilize the knee joint. One week after operation they were assigned to three groups; irradiance 3.9 W/cm2, 5.8 W/cm2, and sham treatment. After 6 times of treatment for another 2 weeks both hind legs were prepared for 1) indentation of the articular surface of the knee (stiffness and loss tangent), and for 2) dual energy X-ray absorptiometry (bone mineral density) of the focused regions.
RESULTS AND CONCLUSIONS: The indentation test revealed preservation of articular cartilage stiffness with 3.9 and 5.8 W/cm2 therapy. Soft laser treatment has a possibility for prevention of biomechanical changes by immobilization.
The Biological Effects of Laser Therapy and Other Physical Modalities on Connective Tissue Repair Processes
Chukuka S. Enwemeka, P.T., Ph.D., FACSM, G. Kesava Reddy, Ph.D.,
Department of Physical Therapy and Rehabilitation Sciences,
University of Kansas Medical Center, Kansas City, KS 66160-7601, USA
Connective tissue injuries, such as tendon rupture and ligamentous strains, are common. Unlike most soft tissues that require 7-10 days to heal, primary healing of tendons and other dense connective tissues take as much as 6 – 8 weeks during which they are inevitably protected in immobilization casts to avoid re-injury. Such long periods of immobilization impair functional rehabilitation and predispose a multitude of complications that could be minimized if healing is quickened and the duration of cast immobilization reduced. In separate studies, we tested the hypothesis that early function, ultrasound, 632.8 nm He-Ne laser, and 904 nm Ga-As laser, when used singly or in combination, promote healing of experimentally severed and repaired rabbit Achilles tendons as evidenced by biochemical, biomechanical, and morphological indices of healing. Our results demonstrate that: (1) appropriate doses of each modality, i.e., early functional activities, ultrasound, He-Ne and Ga-As laser therapy augment collagen synthesis, modulate maturation of newly synthesized collagen, and overall, enhance the biomechanical characteristics of the repaired tendons. (2) Combinations of either of the two lasers with early function and either ultrasound or electrical stimulation further promote collagen synthesis when compared to functional activities alone. However, the biomechanical effects measured in tendons receiving the multi-therapy were similar, i.e., not better than the earlier single modality trials. Although tissue repair processes in humans may differ from that of rabbits, these findings suggest that human cases of connective tissue injuries, e.g., Achilles tendon rupture, may benefit from appropriate doses of He-Ne laser, Ga-As laser, and other therapeutic modalities, when used singly or in combination. Our recent meta-analysis of the laser therapy literature further corroborate these findings.