Chukuka S. Enwemeka

The Efficacy of Laser Therapy in Wound Repair: A Meta-Analysis of the Literature

OBJECTIVE We determined the overall effects of laser therapy on tissue healing by aggregating the literature and subjecting studies meeting the inclusion and exclusion criteria to statistical meta-analysis. BACKGROUND DATA Low-level laser therapy (LLLT) devices have been in use since the mid sixties, but their therapeutic value remains doubtful, as the literature seems replete with conflicting findings. MATERIALS AND METHODS Pertinent original research papers were gathered from library sources, online databases and secondary sources. The papers were screened and coded; those meeting every inclusion and exclusion criterion were subjected to meta-analysis, using Cohens d. statistic to determine the treatment effect size of each study. RESULTS Twenty-four studies with 31 effect sizes met the stringent inclusion and exclusion criteria. The overall mean effect of laser therapy on wound healing was highly significant (d = +2.22). Sub-analyses of the data revealed significant positive effects on wound healing in animal experiments (d = +1.97) as well as human clinical studies (d = +0.54). The analysis further revealed significant positive effects on specific indices of healing, for example, acceleration of inflammation (d = +4.45); augmentation of collagen synthesis (d = +1.80); increased tensile strength (d = +2.37), reduced healing time (d = +3.24); and diminution of wound size (d = +0.55). The Fail-Safe number associated with the overall effect of laser therapy was 509; a high number representing the number of additional studies-in which laser therapy has negative or no effect on wound healing-required to negate the overall large effect size of +2.22. The corresponding Fail-Safe number for clinical studies was 22. CONCLUSION We conclude that laser therapy is an effective tool for promoting wound repair.

The biomechanical effects of low-intensity ultrasound on healing tendons

The effect of low-intensity ultrasound on the healing strength of tendons was studied in experimentally tenotomized, repaired and immobilized right tendo calcaneus (Achilles tendon) of 24 rabbits. Ten tendons were sonicated in continuous waves at a space-averaged intensity of 0.5 W cm-2 for 5 min every day. The remaining 14 tendons were mock-sonicated as controls. After nine consecutive treatments, the tendons were excised under anesthesia and compared for differences in tensile strength, tensile stress and energy absorption capacity. Sonication at 0.5 W cm-2 induced a significant increase in the tensile strength (p less than .02), tensile stress (p less than .005) and energy absorption capacity (p less than .001) of the tendons. These findings suggest that high-intensity sonication may not be necessary to augment the healing strength of tendons and that sonication at similarly low intensities may enhance the healing process of surgically repaired human tendo calcaneus.

Blue 470-nm Light Kills Methicillin-Resistant Staphylococcus aureus (MRSA) in Vitro

BACKGROUND DATA In a previous study, we showed that 405-nm light photo-destroys methicillin-resistant Staphylococcus aureus (MRSA). The 390-420 nm spectral width of the 405-nm superluminous diode (SLD) source may raise safety concerns in clinical practice, because of the trace of ultraviolet (UV) light within the spectrum. OBJECTIVE Here we report the effect of a different wavelength of blue light, one that has no trace of UV, on two strains of MRSA--the US-300 strain of CA-MRSA and the IS-853 strain of HA-MRSA--in vitro. MATERIALS AND METHODS We cultured and plated each strain, and then irradiated each plate with 0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 25, 30, 35, 40, 45, 50, 55, or 60 J/cm2 of energy a single time, using a 470-nm SLD phototherapy device. The irradiated specimens were then incubated at 35 degrees C for 24 h. Subsequently, digital images were made and quantified to obtain colony counts and the aggregate area occupied by bacteria. RESULTS Photo-irradiation produced a statistically significant dose-dependent reduction in both the number and the aggregate area of colonies formed by each strain (p < 0.001). The higher the dose the more bacteria were killed, but the effect was not linear, and was more impressive at lower doses than at higher doses. Nearly 30% of both strains was killed with as little as 3 J/cm2 of energy. As much as 90.4% of the US-300 and the IS-853 colonies, respectively, were killed with an energy density of 55 J/cm2. This same dose eradicated 91.7% and 94.8% of the aggregate area of the US-300 and the IS-853 strains, respectively. CONCLUSION At practical dose ranges, 470-nm blue light kills HA-MRSA and CA-MRSA in vitro, suggesting that a similar bactericidal effect may be attained in human cases of cutaneous and subcutaneous MRSA infections.

Intricacies of Dose in Laser Phototherapy for Tissue Repair and Pain Relief

Inaccurate measurement and incorrect reporting of dosages are major shortcomings of phototherapy articles. As many as 30% of published reports in the field either lack relevant information needed to determine a dosage or report dosages that are altogether inaccurate. The high prevalence of dosage-related mistakes in published reports suggests that dosage determination errors are common among clinicians and other end-users. This special article is designed to advance understanding of the relevant parameters used in phototherapy for tissue repair and pain relief, particularly among clinicians and others who may not be completely familiar with the technology. I define and discuss five key parameters that influence dosage, including 1) radiant power, 2) radiant energy, 3) power density, 4) energy density, and 5) wavelength, and use hypothetical cases to demonstrate how factors such as beam spot size, size of lesion, mode of treatment (contact, noncontact, or scanning), frequency of treatment, dose per treatment, and cumulative dose affect dosages and treatment outcomes. The potential effects of patient-related factors, such as etiology, pathology, tissue optical density, depth of target tissue, and skin pigmentation are discussed concurrently and strategies are suggested to improve dosage determination.

Phototherapy Improves Healing of Chronic Venous Ulcers

OBJECTIVE We tested the hypothesis that LED phototherapy with combined 660-nm and 890-nm light will promote healing of venous ulcers that failed to respond to other forms of treatment. BACKGROUND DATA A variety of dressings, growth factors, and adjunct therapies are used to treat venous ulcers, but none seems to yield satisfactory results. MATERIALS AND METHODS We used a randomized placebo-controlled double-blind study to compare a total of 20 patients divided with 32 chronic ulcers into three groups. In group 1 the ulcers were cleaned, dressed with 1% silver sulfadiazine (SDZ) cream, and treated with placebo phototherapy (<.03 J/cm(-3)) using a Dynatron Solaris 705 phototherapy research device. In group 2 the ulcers were treated similarly but received real phototherapy (3 J/cm(-2)) instead of placebo. In group 3 (controls), the ulcers were simply cleaned and dressed with SDZ without phototherapy. The ulcers were evaluated with digital photography and computer image analysis over 90 d or until full healing was attained. RESULTS Ulcers treated with phototherapy healed significantly faster than controls when compared at day 30 (p +/- 0.01), day 60 (p +/- 0.05), and day 90 (p +/- 0.001), and similarly healed faster than the placebo-treated ulcers at days 30 and 90 (p +/- 0.01), but not at day 60. The beneficial effect of phototherapy was more pronounced when the confounding effect of small-sized ulcers was removed from the analysis. Medium- and large-sized ulcers healed significantly faster with treatment (>or=40% rate of healing per month) than placebo or control ulcers (p +/- 0.05). CONCLUSION Phototherapy promotes healing of chronic venous ulcers, particularly large recalcitrant ulcers that do not respond to conventional treatment.

A Meta-analysis of the Efficacy of Laser Phototherapy on Pain Relief

ObjectiveLaser phototherapy has been widely used to relieve pain for more than 30 years, but its efficacy remains controversial. To ascertain the overall effect of phototherapy on pain, we aggregated the literature and subjected the studies to statistical meta-analysis. MethodsRelevant original studies were gathered from every available source and coded. Articles that met preestablished inclusion criteria were subjected to statistical meta-analysis, using Cohens d statistic to determine treatment effect sizes. ResultsFifty-two effect sizes were computed from the 22 articles that met the inclusion criteria. The resulting overall mean effect size was highly significant; d=+0.84 (95% confidence interval=0.44-1.23). The effect size remained significant even when a high outlying d value was conservatively excluded from the analysis; d=+0.66 (95% confidence interval=0.46-0.86). The fail-safe number associated with the overall treatment effect, that is, the number of additional studies in which phototherapy has negative or no effect on pain needed to negate the overall large effect size of +0.84, was 348. DiscussionThese findings warrant the conclusion that laser phototherapy effectively relieves pain of various etiologies; making it a valuable addition to contemporary pain management armamentarium.

Ultrastructural morphometry of membrane-bound intracytoplasmic collagen fibrils in tendon fibroblasts exposed to He : Ne laser beam

Collagen fibrils are not found in fibroblast cytoplasm except in certain pathological conditions or in the presence of drugs and other agents that accelerate collagen turnover. Because low energy laser photostimulation is both a non-pathogenic and non-chemical accelerator of collagen synthesis, its effects were studied on four groups of calcaneal tendons from 18 rabbits (1) to test the hypothesis that vacuolar fibrils are not produced exclusively by diseases and chemical agents, and (2) to compare the morphometry of matrical and vacuolar fibrils. The right calcaneal tendons of nine rabbits were surgically tenotomized and repaired; six of these were transcutaneously irradiated with He:Ne laser everyday. The right calcaneal tendon of six of the remaining nine rabbits were similarly irradiated with laser, but without prior tenotomy and repair. 21 days later, all tendons were fixed in situ and processed for electron microscopy. Fibril-bearing vacuoles were found only in fibroblasts of tenotomized laser-irradiated tendons. Similar vacuoles were not seen in non-tenotomized laser-irradiated tendons nor in non-irradiated tendons whether tenotomized or not. Mann-Whitney U tests revealed no statistically significant differences in the cross-sectional areas or diameters of matrical and vacuolar fibrils. These findings suggest (a) that matrical and vacuolar fibrils have a common origin, and (b) that vacuolar fibrils can be induced by a non-pathologic, non-chemical accelerator of collagen synthesis.

Wavelength and Bacterial Density Influence the Bactericidal Effect of Blue Light on Methicillin-Resistant Staphylococcus aureus (MRSA)

OBJECTIVE The purpose of this study was to investigate the effect of wavelength and methicillin-resistant Staphylococcus aureus (MRSA) density on the bactericidal effect of 405 and 470 nm light. BACKGROUND DATA It is recognized that 405 and 470 nm light-emitting diode (LED) light kill MRSA in standard 5 × 10(6) colony-forming units (CFU)/mL cultures; however, the effect of bacterial density on the bactericidal effect of each wavelength is not known. METHODS In three experiments, we cultured and plated US300 MRSA at four densities. Then, we irradiated each plate once with either wavelength at 0, 1, 3, 45, 50, 55, 60, and 220 J/cm(2). RESULTS Irradiation with either wavelength reduced bacterial colonies at each density (p<0.05). More bacteria were cleared as density increased; however, the proportion of colonies cleared, inversely decreased as density increased--the maximum being 100%, 96%, and 78% for 3 × 10(6), 5 × 10(6), and 7 × 10(6) CFU/mL cultures, respectively. Both wavelengths had similar effects on the sparser 3 × 10(6) and 5 × 10(6) CFU/mL cultures, but in the denser 7 × 10(6) CFU/mL culture, 405 nm light cleared more bacteria at each fluence (p<0.001). To determine the effect of beam penetration, denser 8 × 10(6) and 12 × 10(6) CFU/mL culture plates were irradiated either from the top, the bottom, or both directions. More colonies were eradicated from plates irradiated from top and bottom, than from plates irradiated from top or bottom at the same sum total fluences (p<0.001). CONCLUSIONS The bactericidal effect of LED blue light is limited more by light penetration of bacterial layers than by bacterial density per se.

Ultrastructural morphometry of matrical changes induced by exercise and food restriction in the rat calcaneal tendon.

The ultrastructural morphometry of collagen fibril populations in 24 calcaneal tendons obtained from 12 Fischer 344 rats were studied to elucidate matrical changes induced by food restriction and/or endurance exercise. Rats were randomly assigned to four equal groups: ad libitum control (AC), ad libitum exercise (AE), restricted diet control (RC) and restricted diet exercise (RE) groups. Beginning from 6 weeks of age, animals in the two food restriction groups were fed 60% of the mean food consumption of ad libitum fed rats. Then, starting from 6-7 months of age, the rats in the two exercise groups performed 40-50 min of treadmill running at 1.2-1.6 miles h-1 every day for a total of 10 weeks. Endurance training did not significantly alter body weight, but food restriction with or without exercise resulted in a significant loss of body weight. In ad libitum fed controls, food restriction alone did not significantly alter the mean collagen fibril CSA, but predisposed a preponderance of small-sized collagen fibrils. Endurance training per se induced a significant (32%) increase in mean fibril CSA (P less than 0.05), but this adaptive response to exercise was prevented by food restriction, as indicated by a 33% decline in fibril CSA (P less than 0.05). These findings demonstrate that dietary restriction modifies the adaptation of tendon collagen morphometry in response to endurance training, and that weight loss is better achieved with food restriction than endurance exercise.

A Meta-analysis of the Efficacy of Phototherapy in Tissue Repair

OBJECTIVE The effect of phototherapy on tissue repair was determined by aggregating the literature and using statistical meta-analysis to analyze pertinent studies published between 2000 and 2007. BACKGROUND DATA Phototherapy has been used for more than 40 y; however, its efficacy on tissue repair remains contentious. METHOD Related original studies were gathered from every available source. The papers were then screened and coded; those meeting pre-established inclusion criterion were subjected to meta-analysis, using Cohens d statistic to determine treatment effect size. RESULTS Seventy effect sizes were computed from the 23 papers that met the inclusion criteria. The overall mean effect obtained was highly significant, d = +1.94 (95% confidence interval = 0.58-2.50). Further analyses revealed a similarly positive effect of phototherapy on tissue repair in experimental animal studies, d = +2.60, and a small to moderately positive effect in human cases of tissue repair, d = +0.34. The fail-safe number associated with the overall effect was 869; i.e., the number of additional studies in which phototherapy has negative or no effect on wound healing needed to negate the overall large effect size of + 1.94. The corresponding fail-safe numbers for experimental animal and human tissue repair studies were 612 and 64, respectively. CONCLUSION These findings indicate that phototherapy is a highly effective form of treatment for tissue repair, with stronger supporting evidence resulting from experimental animal studies than human studies.