Correlations between light penetration into skin and the therapeutic outcome following laser therapy of port-wine stains

Effectiveness of photobiomodulation therapy in the treatment of patients with an ankle sprain: a systematic review and meta-analysis

BACKGROUND

Photobiomodulation therapy (PBMT) is widely used in the treatment of patients with musculoskeletal and sports disorders with a lack of significance in patients with sprain ankle.

PURPOSE

This review investigated the effect of PBMT on pain, oedema, and function in patients with an ankle sprain.

METHODS

A systematic search of the databases (MEDLINE, PubMed, EBSCO, Web of Science, Wiley Online Library, Science Direct, Physiotherapy Evidence (PEDro), and the Cochrane Databases) was performed from inception to the end of 2023 to identify any clinical study investigating the effect of PBMT on ankle sprain. PBMT parameters and measured outcomes were extracted. The primary measured outcome was pain and function, and oedema were secondary measured outcomes. Methodological quality was assessed using the PEDro scale. The level of evidence was determined by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. A random effect meta-analysis with forest plot was used to calculate standardized mean difference (SMD) at a 95% confidence interval and the overall effect size (ES).

RESULTS

Six studies (598 patients) were included in the review and five studies in the meta-analysis. There were two fair-quality and four good-quality studies, with a moderate level of evidence on pain, and a low level of evidence on oedema and function. The meta-analysis revealed a significant overall effect of PBMT on pain with high ES [SMD - 0.88 (-1.76, -0.00), p = 0.05], with a non-significant effect on oedema and function with a medium ES [SMD - 0.70 (-1.64, 0.24), p = 0.14] on oedema and low ES on function [SMD - 0.22 (-0.69, 0.24), p = 0.35]. Significant heterogeneity was observed in all measured outcomes with high heterogeneity (I2 > 75%) in pain and oedema and moderate heterogeneity in function.

CONCLUSION

PBMT is quite effective for patients with an ankle sprain. PBMT showed high effect size with a moderate level of evidence on pain intensity. The lack of significant effects of PBMT on function and edema with low level of evidence limit the confidence to the current results and recommend further large high-quality studies with higher PBMT intensity and fluency for standardisation of the irradiation parameters and treatment protocol.

REGISTRATION

PROSPERO registration number (CRD42021292930).

Current clinical evidence is insufficient to support HMME-PDT as the first choice of treatment for young children with port wine birthmarks

BACKGROUND

Port wine birthmark (PWB) is a congenital vascular malformation of the skin. Pulsed dye laser (PDL) is the "gold standard" for the treatment of PWB globally. Hematoporphyrin monomethyl ether (HMME or hemoporfin)-mediated photodynamic therapy (HMME-PDT) has emerged as the first choice for PWB treatment, particularly for young children, in many major hospitals in China during the past several decades.

AIM

To evaluate whether HMME-PDT is superior to PDL by comparing the clinical efficacies of both modalities.

METHOD

PubMed records were searched for all relevant studies of PWB treatment using PDL (1988-2023) or HMME-PDT (2007-2023). Patient characteristics and clinical efficacies were extracted. Studies with a quartile percentage clearance or similar scale were included. A mean color clearance index (CI) per study was calculated and compared among groups. An overall CI (C0), with data weighted by cohort size, was used to evaluate the final efficacy for each modality.

RESULT

A total of 18 HMME-PDT studies with 3910 patients in China were eligible for inclusion in this analysis. Similarly, 40 PDL studies with 5094 patients from nine different countries were eligible for inclusion in this analysis. Over 58% of patients in the HMME-PDT studies were minors (<18 years old). A significant portion (21.3%) were young children (<3 years old). Similarly, 33.2% of patients in the PDL studies were minors. A small proportion (9.3%) was young children. The overall clearance rates for PDL were slightly, but not significantly, higher than those for HMME-PDT in cohorts with patients of all ages (C0, 0.54 vs. 0.48, p = 0.733), subpopulations with only minors (C0, 0.54 vs. 0.46, p = 0.714), and young children (C0, 0.67 vs. 0.50, p = 0.081). Regrettably, there was a lack of long-term data on follow-up evaluations for efficacy and impact of HMME-PDT on young children in general, and central nervous system development in particular, because their blood-brain barriers have a greater permeability as compared to adults.

CONCLUSION

PDL shows overall albeit insignificantly higher clearance rates than HMME-PDT in patients of all ages; particularly statistical significance is nearly achieved in young children. Collectively, current evidence is insufficient to support HMME-PDT as the first choice of treatment of PWBs in young children given: (1) overall inferior efficacy as compared to PDL; (2) risk of off-target exposure to meningeal vasculature during the procedure; (3) administration of steriods for mitigation of side effects; -and (4) lack of long-term data on the potential impact of HMME on central nervous system development in young children.

Time interval between pulse dye laser treatments of port-wine stains: 30 years of experience

Port-wine stains (PWS) are frequently refractory to laser treatments. The aim of this study is to evaluate the role of treatment interval time. From 1990, 216 patients underwent Pulsed Dye Laser sessions. The laser sessions were scheduled at a minimum interval of 4 weeks to a maximum of 48 weeks. Clinical outcomes were assessed 8 weeks after the last laser session. Better results were obtained with 8 weeks interval time between therapy session, and high efficacies were also found for intervals of 4, 6 and 10 weeks. For greater interval instead, the effectiveness is significantly lower.

Curcumin-loaded multifunctional chitosan gold nanoparticles: An enhanced PDT/PTT dual-modal phototherapeutic and pH-responsive antimicrobial agent

Overuse of antibiotics has led to the emergence of multidrug resistant (MDR) bacteria.. Photothermal (PTT) and photodynamic therapy (PDT) have may be effective alternatives for antibiotics in the treatment of bacterial infections. In this study, based on chitosan (CS)-coated gold nanoparticles, a pH stimulus-responsive drug delivery system was developed, which can anchor to the cell membrane for photodynamic therapy and photothermal therapy, and enhance the therapeutic potential of curcumin (Cur). Release experiments showed that AuNPs/CS-Cur nanocomposites released curcumin in a pH-dependent manner, which may facilitate the drug to be delivered to the acidic bacterial infection environment. CS as the outer layer covered on gold nanoparticles could improve the dispersibility of Cur in aqueous solution, gold nanoparticles prevent rapid photobleaching of curcumin, thus ensuring the yield of singlet oxygen under irradiation, and enhance the electrostatic binding with bacteria cell membrane. Under light conditions, AuNPs/CS-Cur can produce a large amount of reactive oxygen species and heat to kill S. aureus and E. coli. Compared with free Cur-mediated PDT, the complex significantly improved the synergistic PTT/PDT photoinactivation ability against S. aureus and E. coli. In addition, AuNPs/CS-Cur had good biocompatibility. Therefore, AuNPs/CS-Cur possessed the characteristics of electrostatic targeting, photodynamic and photothermal antibacterial therapy, which would become an efficient and safe antibacterial nano-platform and provide new ideas for the treatment of bacterial infection.

Therapeutic Strategies for Untreated Capillary Malformations of the Head and Neck Region: A Systematic Review and Meta-Analyses

Background

Capillary malformations of the head and neck region often cause psychological and physical burden. As the effectiveness of modern laser and light therapies is still suboptimal, patients often seek different therapeutic strategies. Other recognized, but not routinely proposed therapies include cosmetic camouflage, surgery, and medical tattooing. Information on therapeutic outcomes is currently lacking for patients to adequately participate in the treatment decision-making process.

Objective

The objective of this systematic review was to review the effectiveness and safety of recognized therapies for untreated capillary malformations of the head and neck: laser and light treatment modalities, photodynamic therapy, cosmetic camouflage, medical tattooing, and surgery.

Methods

PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched up to 16 December, 2020 for observational and experimental studies examining recognized therapies for untreated capillary malformations of the head and neck. Two reviewers independently evaluated the risk of bias of included studies. Predefined treatment and safety outcomes of pooled data were scored using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Results

We included 48 observational and three randomized studies (totaling 3068 patients), evaluating nine different therapies. No studies on surgery or cosmetic camouflage matched our inclusion criteria. The pooled proportion of patients reaching a ≥75% clearance was 43% (95% confidence interval 24–64%; I² = 55%) for the pulsed dye laser after three to eight treatment sessions (GRADE score: very low). Other therapies were less effective. Hyperpigmentation was most frequently described after the pulsed dye laser (incidences up to 40%). Pain was most common after photodynamic therapy, yet the intensity was unreported. Substantial heterogeneity among studies as to patient characteristics and outcomes limited pooling and data comparisons.

Conclusions

The pulsed dye laser seems preferable for treatment-naive capillary malformations of the head and neck region, yet demonstrates greater hyperpigmentation rates compared with other therapies. Our results are, however, based on low-quality evidence. Future studies using uniform outcome measures and validated metrics are warranted for study comparability. Based on this systematic review, clinicians and patients should be aware of the limited evidence about the available options when making (shared) treatment decisions for capillary malformations.

Trial Registration

Review registration number PROSPERO database: CRD42020199445.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40257-021-00616-5.

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

Simple Summary

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

Abstract

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

Pulsed ND:YAG laser combined with progressive pressure release in the treatment of cervical myofascial pain syndrome: a randomized control trial

[Purpose] To investigate the effect of pulsed Nd:YAG laser combined with the progressive pressure release technique (PPRT) and exercises in the treatment of myofascial trigger points (MTrPs) in patients with myofascial pain syndrome (MPS). [Participants and Methods] A total of 50 patients with MTrPs in the upper trapezius muscle participated in the study. The patients were randomly assigned to two groups and treated with laser plus PPRT (Laser + PPRT group) or placebo laser and exercises (PL + PPRT group). The laser was applied for eight MTrPs with a 50 J/point. PPRT was applied for 30 seconds for each point. Exercises included strengthening and stretching exercises applied three times per week for four weeks. A visual analogue scale (VAS) and pressure pain threshold (PPT) were used to measure pain and pain threshold, respectively. A cervical range of motion device (CROM) was used to measure the cervical range of motion. [Results] Both treatment groups showed significant improvement in CROM, PPT, and VAS post-treatment with a more significant effect in the Laser + PPRT group compared to the PL + PPRT group. [Conclusion] PPRT and exercises alone or that in combination with laser therapy were effective in the treatment of active MTrPs in patients with MPS.

Capillaroscopy and reflectance confocal microscopy characterization of refractory port-wine stains

Port-wine stains (PWS) are frequently refractory to laser treatments. Although previous data highlight prognostic factors and biological events related to poor outcomes, no previous publications correlate their capillaroscopic and architectural features. The aim of the present study is to describe refractory port-wine stains performing capillaroscopy and reflectance confocal microscopy (RCM) to describe their morphological and microscopic aspects. This is a prospective cohort study. All the consecutive patients with PWS poor responsive to previous treatment were included. Clinical assessment, capillaroscopy, and reflectance confocal microscopy were performed. A total of 65 patients were included, 12 with a capillaroscopic Type II pattern patients and 53 with Type III. At RCM examination, PWS with a capillaroscopic Type III pattern showed deeper-located blood vessels (p < 0.001) with a higher diameter (p < 0.042) compared with Type II. At the dynamic evaluation, 3 RCM patterns can be distinguished: Subset A, characterized by linear vessels with reduced diameter; Subset B, formed by enlarged vessels; and Subset C, characterized by deep and large aneurysmatic dilatation connected to small vessels. We defined 3 RCM patterns of refractory PWS.

The effectiveness of high intensity laser therapy in the management of spinal disorders: A systematic review and meta-analysis

BACKGROUND

Spinal disorders are common health problems which include wide categories of diseases that affect the spinal soft tissues, joints and bone.

OBJECTIVE

The aim of this systematic review was to evaluate the effectiveness of high intensity laser therapy (HILT) on pain and function in patients with spinal disorders.

METHODS

Six databases were searched up to the end of February 2018 including PubMed, MEDLINE, the Cochrane Central Register of Controlled Trials (CENTRAL), Physiotherapy Evidence Database (PEDro), Open Grey and Grey Literature Report. In addition, the reference lists of all included studies were searched for any relevant studies. PEDro scale and GRADE system were performed to assess the quality of the studies. A meta-analysis was conducted to calculate the overall effect size.

RESULTS

A total of ten randomised controlled trials (RCTs) met the inclusion criteria, with four studies of the efficacy of HILT on neck pain (NP) and six on low back pain (LBP). According to the PEDro scale assessment, only two studies were rated as high quality, while the remainder were rated as fair or low quality. Forest plots showed that HILT with exercise was significantly more effective than placebo HILT with exercise in terms of pain reduction (SMD -1.11; 95% CI -1.42 to -0.80; P< 0.00001; I2 0%) and functional improvement (SMD -1.03; 95% CI -1.33 to -0.72; P< 0.00001; I2 0%). Meta-analyses also showed that HILT alone or HILT with conventional physiotherapy (CPT) significantly provided better outcomes than CPT alone.

CONCLUSIONS

HILT is considered as a complementary modality for pain reduction and function improvement in patients with spinal disorders. However, the quality of the body of evidence was rated from 'very low' to 'low' quality. Further high quality trials are required for standardisation of irradiation parameters and the treatment protocol to establish the efficacy of HILT for spinal disorders.

Port wine stain treatment outcomes have not improved over the past three decades

BACKGROUND

Since the early '80s, the pulsed dye laser has been the standard treatment tool for non-invasive port wine stain (PWS) removal. In the last three decades, a considerable amount of research has been conducted to improve clinical outcomes, given that a fraction of PWS patients proved recalcitrant to laser treatment. Whether this research actually led to increased therapeutic efficacy has not been systematically investigated.

OBJECTIVE

To analyse therapeutic efficacy in PWS patients globally from 1986 to date.

METHODS

PubMed was searched for all available PWS trials. Studies with a quartile percentage improvement scale were included, analysed and plotted chronologically. Treatment and patient characteristics were extracted. A mean clearance per study was calculated and plotted. A 5-study simple moving average was co-plotted to portray the trend in mean clearance over time. The data were separately analysed for multiple treatment sessions in previously untreated patients.

RESULTS

Sixty-five studies were included (24.3% of eligible studies) comprising 6207 PWS patients. Of all patients, 21% achieved 75-100% clearance. Although a few studies reported remarkably good outcomes in a subset of carefully selected patients, there was no upward trend over time in mean clearance.

CONCLUSION

The efficacy of PWS therapy has not improved in the past decades, despite numerous technical innovations and pharmacological interventions. With an unwavering patient demand for better outcomes, the need for development and implementation of novel therapeutic strategies to clear all PWS is as valid today as it was 30 years ago.

Changes in local skin temperature after the application of a pulsed Nd:YAG laser to healthy subjects: a prospective crossover controlled trial

Pulsed Nd:YAG laser (1064 nm) is a recent modality that is used for the rehabilitation of musculoskeletal disorders, but there is no evidence about its thermal effects. The aim of the study was to investigate the changes in local skin temperature (LST) after the application of a pulsed Nd:YAG laser to healthy subjects. The study participants were 30 male subjects with an average age of 21.96 (± 0.92) years. A rectangular area (15 × 10 cm²) was marked at the front of the dominant thigh and scanned with a laser beam at 3000 J with 20 J/cm² for 15 min. The other thigh was considered as a control side. The minimum, average, and maximum LSTs were measured using a thermographic camera. The measurements were performed before laser application, immediately after, and then every minute until the LST returned to the pre-treatment value. An independent t test and repeated measures ANOVA were used to analyze the changes in LST. The level of significance was set at p < 0.05. The pulsed Nd:YAG laser significantly increased the minimum, average, and maximum LSTs in comparison with the control. The increase was significant for up to 5 min after the application, and it took 10 min to reach the baseline values. The level of increase was 1.23-4.03 °C, and the average increase was 2.6 °C. The pulsed Nd:YAG laser significantly increased the minimum, average, and maximum LSTs of the thigh area in normal subjects, and the thermal effect lasted for 5 min after application.

Dual antibacterial behavior of a curcumin–upconversion photodynamic nanosystem for efficient eradication of drug-resistant bacteria in a deep joint infection

The curcumin–upconversion photodynamic nanosystem exhibits dual antibacterial behavior for MRSA-induced periprosthetic joint infection under NIR irradiation.

Simulated Sunlight-Mediated Photodynamic Therapy for Melanoma Skin Cancer by Titanium-Dioxide-Nanoparticle-Gold-Nanocluster-Graphene Heterogeneous Nanocomposites

Simulated sunlight has promise as a light source able to alleviate the severe pain associated with patients during photodynamic therapy (PDT); however, low sunlight utilization efficiency of traditional photosensitizers dramatically limits its application. Titanium-dioxide-nanoparticle-gold-nanocluster-graphene (TAG) heterogeneous nanocomposites are designed to efficiently utilize simulated sunlight for melanoma skin cancer PDT. The narrow band gap in gold nanoclusters (Au NCs), and staggered energy bands between Au NCs, titanium dioxide nanoparticles (TiO₂ NPs), and graphene can result in efficient utilization of simulated sunlight and separation of electron-hole pairs, facilitating the production of abundant hydroxyl and superoxide radicals. Under irradiation of simulated sunlight, TAG nanocomposites can trigger a series of toxicological responses in mouse B16F1 melanoma cells, such as intracellular reactive oxygen species production, glutathione depletion, heme oxygenase-1 expression, and mitochondrial dysfunctions, resulting in severe cell death. Furthermore, intravenous or intratumoral administration of biocompatible TAG nanocomposites in B16F1-tumor-xenograft-bearing mice can significantly inhibit tumor growth and cause severe pathological tumor tissue changes. All of these results demonstrate prominent simulated sunlight-mediated PDT effects.

Regulation of lipid production by light-emitting diodes in human sebocytes

Light-emitting diodes (LED) have been used to treat acne vulgaris. However, the efficacy of LED on sebaceous lipid production in vitro has not been examined. This study investigated the efficacy of 415 nm blue light and 630 nm red light on lipid production in human sebocytes. When applied to human primary sebocytes, 415 nm blue light suppressed cell proliferation. Based on a lipogenesis study using Oil Red O, Nile red staining, and thin-layered chromatography, 630 nm red light strongly downregulated lipid production in sebocytes. These results suggest that 415 nm blue light and 630 nm red light influence lipid production in human sebocytes and have beneficial effects on acne by suppressing sebum production.

Upconversion nanoparticles conjugated with curcumin as a photosensitizer to inhibit methicillin-resistant Staphylococcus aureus in lung under near infrared light

Curcumin has phototoxic effects on bacteria under <450 nm irradiation, but it is unstable in vivo and cannot exert effects on deep tissues. Near infrared light (NIR) is harmless to the body and has stronger penetration than visible light. In order to improve the effects of curcumin, upconversion nanoparticles conjugated with curcumin (UCNPs-curcumin) are designed to upconvert NIR to the excitation wavelength of curcumin. UCNPs-curcumin were synthesized using polyethyleneimine to combine curcumin and UCNPs, based on typical composition of lanthanide nitrates Re(NO)₃ (Y:Yb:Er=78%:20%:2%) linked by ethylenediaminetetraacetic acid in sodium fluoride (NaF) matrix, to upconvert NIR to 432 nm light. The product was characterized by size distribution, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Growth inhibition of methicillin-resistant Staphylococcus aureus (MRSA) was not only measured in vitro but also investigated on MRSA-induced pneumonia in mice. The results showed that curcumin was covered by UCNPs to form stable nanoparticles whose average size was 179.5 nm and zeta potential was −33.7 mV in normal saline. The UCNPs-curcumin produced singlet oxygen, which reaches a stable level after 30 minutes of irradiation, and took effect on MRSA through bacterial cytoplasm leakage. They alleviated MRSA-induced pneumonia and reduced bacterial counts in lungs with 980 nm irradiation (0.5 W/cm²) on chests of mice. It is confirmed that the UCNPs-curcumin in lungs are activated under NIR irradiation and strengthen their antibacterial effects on MRSA. This research provides a new type of NIR photosensitizer, which plays an important role in phototoxic effects of curcumin in deep tissues under NIR.

Patterns of traditional chinese medicine diagnosis in thermal laser acupuncture treatment of knee osteoarthritis

Knee osteoarthritis (OA) manifests with pain, joint stiffness, and limited function. In traditional Chinese medicine, knee OA is differentiated into three patterns: yang deficiency and cold coagulation, kidney deficiency, and blood stasis. The objective of this study was to determine whether yang deficiency cold coagulation patients respond better to thermal laser acupuncture treatment than do non-yang deficient patients. Fifty-two patients with OA were allocated to group A (yang deficient, n = 26) or B (non-yang deficient, n = 26). All patients received a 20-min thermal laser acupuncture treatment at acupoint Dubi (ST 35) three times a week for two weeks and twice a week for another four weeks. Outcome assessments were performed immediately after the first treatment, and at weeks 2, 6, and 10. Group A function scores were significantly better than those of Group B at weeks 2 (P = 0.049), 6 (P = 0.046), and 10 (P = 0.042), but no significant differences were found between the two groups in pain and stiffness scores at any time point. No significant adverse effect was observed. The combined 10.6 μm–650 nm laser treatment might be most beneficial to yang deficiency cold coagulation knee OA patients, particularly in improving function.

Laser treatment of recurrent herpes labialis: a literature review

Recurrent herpes labialis is a worldwide life-long oral health problem that remains unsolved. It affects approximately one third of the world population and causes frequent pain and discomfort episodes, as well as social restriction due to its compromise of esthetic features. In addition, the available antiviral drugs have not been successful in completely eliminating the virus and its recurrence. Currently, different kinds of laser treatment and different protocols have been proposed for the management of recurrent herpes labialis. Therefore, the aim of the present article was to review the literature regarding the effects of laser irradiation on recurrent herpes labialis and to identify the indications and most successful clinical protocols. The literature was searched with the aim of identifying the effects on healing time, pain relief, duration of viral shedding, viral inactivation, and interval of recurrence. According to the literature, none of the laser treatment modalities is able to completely eliminate the virus and its recurrence. However, laser phototherapy appears to strongly decrease pain and the interval of recurrences without causing any side effects. Photodynamic therapy can be helpful in reducing viral titer in the vesicle phase, and high-power lasers may be useful to drain vesicles. The main advantages of the laser treatment appear to be the absence of side effects and drug interactions, which are especially helpful for older and immunocompromised patients. Although these results indicate a potential beneficial use for lasers in the management of recurrent herpes labialis, they are based on limited published clinical trials and case reports. The literature still lacks double-blind controlled clinical trials verifying these effects and such trials should be the focus of future research.

Skin penetration time-profiles for continuous 810 nm and Superpulsed 904 nm lasers in a rat model

OBJECTIVE

The purpose of this study was to investigate the rat skin penetration abilities of two commercially available low-level laser therapy (LLLT) devices during 150 sec of irradiation.

BACKGROUND DATA

Effective LLLT irradiation typically lasts from 20 sec up to a few minutes, but the LLLT time-profiles for skin penetration of light energy have not yet been investigated.

MATERIALS AND METHODS

Sixty-two skin flaps overlaying rat's gastrocnemius muscles were harvested and immediately irradiated with LLLT devices. Irradiation was performed either with a 810 nm, 200 mW continuous wave laser, or with a 904 nm, 60 mW superpulsed laser, and the amount of penetrating light energy was measured by an optical power meter and registered at seven time points (range, 1-150 sec).

RESULTS

With the continuous wave 810 nm laser probe in skin contact, the amount of penetrating light energy was stable at ∼20% (SEM±0.6) of the initial optical output during 150 sec irradiation. However, irradiation with the superpulsed 904 nm, 60 mW laser showed a linear increase in penetrating energy from 38% (SEM±1.4) to 58% (SEM±3.5) during 150 sec of exposure. The skin penetration abilities were significantly different (p<0.01) between the two lasers at all measured time points.

CONCLUSIONS

LLLT irradiation through rat skin leaves sufficient subdermal light energy to influence pathological processes and tissue repair. The finding that superpulsed 904 nm LLLT light energy penetrates 2-3 easier through the rat skin barrier than 810 nm continuous wave LLLT, corresponds well with results of LLLT dose analyses in systematic reviews of LLLT in musculoskeletal disorders. This may explain why the differentiation between these laser types has been needed in the clinical dosage recommendations of World Association for Laser Therapy.

Investigation into optimal treatment intervals of facial port-wine stains using the pulsed dye laser

BACKGROUND

Port-wine stains (PWS) affect 0.3% to 0.5% of newborns and pulsed dye laser (PDL) remains the treatment of choice. Optimal treatment intervals have not been established.

OBJECTIVE

We sought to validate the optimal treatment intervals for the management of facial PWS with PDL.

METHODS

In all, 24 infants with facial PWS who received at least 5 treatments with the PDL at 2-, 3-, and 4-week intervals at a private laser and skin surgery center from 2009 to 2010 were identified by a retrospective chart review. Safety and efficacy were compared by blinded investigators.

RESULTS

Side effects were equivalent in all interval groups and included only expected short-term erythema, edema, purpura, and mild postinflammatory hyperpigmentation. No patient developed hypopigmentation, scarring, or infection. All interval groups showed 50% to 100% clearance of their PWS after 5 treatments. Complete or near-complete clearance was seen in 6 of 8 (75%) and 7 of 8 (87.5%) patients in the 2- and 3-week interval groups, respectively, as compared with 3 of 8 (37.5%) patients in the 4-week interval group.

LIMITATIONS

This was a retrospective chart review from a single institution. Long-term side effects and recurrence rates were not assessed.

CONCLUSION

We conclude that PDL treatments at 2-, 3-, and 4-week intervals are effective for the management of facial PWS in infants with minimal short-term side effects. Shorter treatment intervals may allow for relatively more rapid and more effective treatment.

Light-sensitive lipid-based nanoparticles for drug delivery: design principles and future considerations for biological applications

Radiation-based therapies aided by nanoparticles have been developed for decades, and can be primarily categorized into two main platforms. First, delivery of payload of photo-reactive drugs (photosensitizers) using the conventional nanoparticles, and second, design and development of photo-triggerable nanoparticles (primarily liposomes) to attain light-assisted on-demand drug delivery. The main focus of this review is to provide an update of the history, current status and future applications of photo-triggerable lipid-based nanoparticles (light-sensitive liposomes). We will begin with a brief overview on the applications of liposomes for delivery of photosensitizers, including the choice of photosensitizers for photodynamic therapy, as well as the currently available light sources (lasers) used for these applications. The main segment of this review will encompass the details of strategies used to develop photo-triggerable liposomes for their drug delivery function. The principles underlying the assembly of photoreactive lipids into nanoparticles (liposomes) and photo-triggering mechanisms will be presented. We will also discuss factors that limit the applications of these liposomes for in vivo triggered drug delivery and emerging concepts that may lead to the biologically viable photo-activation strategies. We will conclude with our view point on the future perspectives of light-sensitive liposomes in the clinic.

Vascular malformations

Vascular malformations are rare but important skin disorders in children, which often require multidisciplinary care. The goal of this article is to orient pediatricians to the various types of vascular malformations. We discuss the clinical characteristics, diagnostic criteria, and management of capillary, venous, arteriovenous, and lymphatic malformations. Associated findings and syndromes are also discussed briefly.

Does dye laser treatment with higher fluences in combination with cold air cooling improve the results of port-wine stains?

BACKGROUND AND OBJECTIVE

The use of cold air cooling (CAC) and cryogen spray cooling during dye laser treatment of port-wine stains (PWS) has become a standard in recent years. Still unsolved is the question of which fluences are necessary in combination with CAC in order to achieve an optimum clearance and the lowest possible rate of side-effects.

STUDY DESIGN

In a prospective study, we treated 11 patients with PWS with pulsed dye laser (Photogenica V, Cynosure, lambda = 585 nm, iota(p) = 0.5 ms, spot size = 7 mm). Each PWS was partitioned into three areas: (area 1) 6 J/cm(2) without CAC, (area 2) 6 J/cm(2) with CAC (level 4), (area 3) 9 J/cm(2) with CAC (level 4).

RESULTS

Area 3 (mean, 59%) showed a slightly better clearance than area 1 (mean, 57%); in area 2, we observed a reduced clearance (mean, 45%). Compared with area 1, we achieved a reduction of pain through CAC in areas 2 and 3. The healing periods as well as the rate of side-effects were comparable in all areas.

CONCLUSION

We observed a slight but not statistically relevant increase in clearance with the use of higher fluences and CAC compared with lower fluences without CAC. Because pain is lowered significantly when using CAC, and because this makes the treatment more comfortable for the patients, we tend to recommend the use of higher fluences (9 J/cm(2)) with simultaneous CAC for treating PWS.

Effect of combined laser acupuncture on knee osteoarthritis: a pilot study

Our objective was to assess the efficacy and safety of combined 10.6 microm and 650 nm laser irradiation on patients with knee osteoarthritis (OA). Forty patients with OA were randomly allocated to an active laser group or to a placebo laser group (20 per group). They either received active or sham laser treatment at acupoint Dubi (ST 35) in a total of 12 sessions. There was significant difference between the two groups in the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index pain score change from baseline after 2 weeks of treatment (P = 0.047). The pain reduction of the active laser treatment group was 49%, whereas that of the placebo control group was only 13%. However, due to the high patient drop-out rate, the 4-week assessment could not be analyzed. Combined laser treatment seems beneficial to patients with knee OA. However, due to the small sample size and the high drop-out rate of patients in the placebo group, a large sample-size clinical trial is warranted to determine further the therapeutic efficacy of the device.

In vitro fluorescence measurements and Monte Carlo simulation of laser irradiation propagation in porcine skin tissue

In dermatology, the in vivo spectral fluorescence measurements of human skin can serve as a valuable supplement to standard non-invasive techniques for diagnosing various skin diseases. However, quantitative analysis of the fluorescence spectra is complicated by the fact that skin is a complex multi-layered and inhomogeneous organ, with varied optical properties and biophysical characteristics. In this work, we recorded, in vitro, the laser-induced fluorescence emission signals of healthy porcine skin, one of the animals, which is considered as one of the most common models for investigations related to medical diagnostics of human cutaneous tissues. Differences were observed in the form and intensity of the fluorescence signal of the porcine skin, which can be attributed to the different concentrations of the native fluorophores and the variable physical and biological conditions of the skin tissue. As the light transport in the tissue target is directly influencing the absorption and the fluorescence emission signals, we performed Monte Carlo simulation of the light distribution in a five-layer model of human skin tissue, with a pulsed ultraviolet laser beam.

Vascular malformations: Part I

Cutaneous vascular malformations are rare disorders representing errors in vascular development. These lesions occur much less commonly but are often confused with the common infantile hemangioma. It is important to properly diagnose vascular malformations because of their distinct differences in morbidity, prognosis and treatment. Vascular malformations may be associated with underlying disease or systemic anomalies. Several of these syndromes are well defined and can often be distinguished on the basis of the flow characteristics of the associated vascular malformation.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should have a better understanding of the different types of cutaneous vascular malformations. Because of the importance of proper diagnosis of these lesions, participants should also be better able to direct correct management and treatment.

Optimal parameters for the treatment of leg veins using Nd:YAG lasers at 1064 nm

BACKGROUND

The treatment of large vessels such as leg veins is successfully performed in clinical practice using pulsed Nd:YAG lasers. However, it is still unclear how laser parameters such as wavelength, fluence and pulse duration influence vessel destruction in leg veins.

OBJECTIVES

To elucidate the governing parameters in selective photothermolysis of large vessels.

METHODS

A recently developed mathematical model for photothermolysis has been adapted for the treatment of leg veins. The model was used to analyse the effectiveness of the selective photothermolysis process in laser treatment of leg veins by Nd:YAG at 1064 nm. The efficiency of laser-induced vessel heating was defined as a ratio between the absorbed and delivered energy.

RESULTS

The efficiency improved with increasing vessel diameter, in agreement with clinical findings in various studies. The pulse duration made a minor contribution for laser fluences of 100-400 J cm(-2), whereas the efficiency was better for a small spot. The use of moderate fluences of 100-200 J cm(-2) reduced excess dermis heating and pain.

CONCLUSIONS

We provide reference parameters for optimal treatment of leg veins using Nd:YAG lasers at 1064 nm. Our model predicts a maximal efficiency of a range of fluences (100-200 J cm(-2)) and pulse durations (10-100 ms).

Pulsed dye laser treatment, a review of indications and outcome based on published trials

INTRODUCTION

Pulsed dye laser (PDL) treatment is based on the principle of selective photothermolysis and is widely considered to be the treatment of choice for a variety of cutaneous vascular lesions.

OBJECTIVE

To review the indications and outcome of PDL treatment and summarise new developments.

METHOD

A literature-based study has been conducted entailing the review of publications over the period January 1993-December 2003 using the databases Medline and Cochrane CENTRAL.

RESULTS

The PDL was found to be effective in port wine stain, facial telangiectasia, leg telangiectasia <0.5 mm, scars, hypertrophic scars and ulcerated haemangioma.

DISCUSSION

Essential characteristics of lesions suitable for PDL treatment are discussed and guidelines are presented for future research.

Thickness of Healthy and Affected Skin of Children with Port Wine Stains: Potential Repercussions on Response to Pulsed Dye Laser Treatment

BACKGROUND

Response of port wine stain to pulsed dye laser therapy is variable and dependent on treatment settings used and anatomic site as well as on size and depth of ectatic vessels.

OBJECTIVE

Our purpose was to evaluate skin thickness in different anatomic areas and in port wine stain to thus assess its possible role in the response to pulsed dye laser.

MATERIALS AND METHODS

Twenty-one children with port wine stain underwent high-frequency ultrasound evaluation (20 MHz). Eighteen unaffected areas were considered in each patient and an additional measure was taken from the symmetric affected skin when present (50 areas).

RESULTS

Skin was thicker in the centrofacial area, dermatome V1 (followed by dermatome V2, dermatome V3, and dermatomes C1-2), and with increasing age. No substantial difference between affected and symmetric nonaffected skin was found.

CONCLUSION

Thicker cutaneous areas fit with those that typically respond worse to pulsed dye laser. Differences in skin thickness related to age support the fact that better responses are achieved in younger patients.

A new mathematical approach to the diffusion approximation theory for selective photothermolysis modeling and its implication in laser treatment of port-wine stains

BACKGROUND AND OBJECTIVES

Monte Carlo (MC) simulations of light-tissue interactions and analytical solutions for the diffusion approximation theory have been used to determine the optimal laser wavelength and radiant exposure to treat port-wine stains (PWS). Both approaches suggest that optimal parameters are a wavelength of 585 or 595-nm with pulse times of 0.45-20 milliseconds. However, which parameters are optimal is still unclear. As differences in vessel size and in temperature distribution within vessels appeared to be the main reasons for the varied responses to the same laser treatments, we sought to develop a solution to the diffusion approximation in order to calculate temperature distribution and the resulting coagulation pattern within specific blood vessels.

STUDY DESIGN/MATERIALS AND METHODS

The light and heat diffusion equations were simultaneously solved with the finite element method (FEM). The latent heat of evaporation was included in the thermal analysis. The temperature and coagulation patterns across specific blood vessels, within a heterogeneous medium, were calculated for laser wavelengths of 585 and 595-nm with clinical parameters.

RESULTS

At 1.2 mm deep, the calculations predicted that vessels ranging from 50 to 100 microm in diameter would be coagulated from top to bottom, small vessels (10 microm) would be spared, and vessels larger than 150 microm would be partially coagulated. Coagulation across vessels was more uniform for the 595-nm than for the 585-nm wavelength. Maximal temperatures did not exceed 100 degrees C because of the inclusion of latent heat in the thermal calculations.

CONCLUSIONS

To study laser treatments of PWS with the diffusion approximation, FEM is an effective method to calculate the coagulation patterns within specific blood vessels. To improve coagulation efficacy at 585 and 595-nm wavelengths, the radiant exposure should be increased without increasing the irradiance.

The depth measuring videomicroscope (DMV): A non-invasive tool for the assessment of capillary vascular malformations

BACKGROUND AND OBJECTIVES

The response of capillary vascular malformations (CVMs) to laser treatment is believed to be due to the pattern of capillary ectasia, the depth, diameter, and flow through these capillaries and the amount of competing chromophores within the skin. Videomicroscopy has successfully been used to determine CVM capillary pattern and diameter of vessels. The depth measuring videomicroscope (DMV) allows the depth of capillaries to be measured also. The aim of this study is to examine how capillary depths within a CVM are affected by dye laser treatment using DMV.

STUDY DESIGN/MATERIALS AND METHODS

Thirteen previously untreated patients were examined in a temperature-controlled room. A DMV examination was carried out prior to and 6 weeks following a treatment with pulsed dye laser. A further cohort of 11 resistant CVM patients, who had all received over five treatments, was also examined for comparison.

RESULTS

Using a Wilcoxon Signed rank test, the results showed that the remaining vessels within the CVM as measured using DMV were more deeply located and smaller (P < 0.01 and P < 0.02 respectively), following the laser treatment. Also in the resistant patients the vessels were again more deeply placed and smaller.

CONCLUSIONS

The hypothesis that smaller and more deeply placed CVM vessels respond poorest to laser treatment is supported by these findings. Moreover, the DMV provides a simple non-invasive technique for demonstrating this.

Laser surgery: new applications for pediatric skin and airway lesions

Recent research pertaining to laser applications for the treatment of capillary malformations (port wine stains) and cutaneous and subglottic hemangiomas is reviewed within the context of advances in laser technology and current therapeutic practices and controversies. Although laser advances have resulted in the concomitant growth of new clinical applications, research over the past year has focused on refining and improving existing applications, with the ultimate goal of being able to individualize treatment. Research initiatives aimed at improving the outcomes of pulse dye laser treatment for capillary malformations have illustrated the complexity of the interaction between laser characteristics, methods of laser application, variations in human skin and tissue, and morphologic parameters of involved blood vessels. Investigations of cutaneous hemangioma have addressed the issue of early pulse dye laser intervention, and results of a significant prospective study clearly demonstrate that this offers no benefit. Studies of subglottic hemangioma have compared the outcomes of treatment with carbon dioxide (CO(2)) and the potassium-titanyl-phosphate lasers, concluding that the latter results in superior outcomes, with less risk of posttreatment subglottic stenosis.