Novel 40 µm spot size 3050/3200 nm DFG laser versus CO2 laser for laser-assisted drug delivery.

BACKGROUND AND OBJECTIVES: The use of ablative fractional lasers to enhance the delivery of topical drugs through the skin is known as laser-assisted drug delivery. Here, we compare a novel 3050/3200 nm difference frequency generation (DFG) fiber laser (spot size: 40 µm) to a commercially used CO2 laser (spot size: 120 µm). The objective is to determine whether differences in spot size and coagulation zone (CZ) thickness influence drug uptake. MATERIALS AND METHODS: Fractional ablation was performed on ex-vivo human abdominal skin with the DFG (5 mJ) and CO2 (12 mJ) lasers to generate 680 µm deep lesions. To evaluate drug delivery, 30 kDa encapsulated fluorescent dye was topically applied to the skin and histologically analyzed at skin depths of 100, 140, 200, 400, and 600 µm. Additionally, transcutaneous permeation of encapsulated and 350 Da nonencapsulated dye was assessed using Franz Cells. RESULTS: The DFG laser generated smaller channels (diameter: 56.5 µm) with thinner CZs (thickness: 22.4 µm) than the CO2 laser (diameter: 75.9 µm, thickness: 66.8 µm). The DFG laser treated group exhibited significantly higher encapsulated dye total fluorescence intensities after 3 h compared to the CO2 laser treated group across all skin depths (p < 0.001). Permeation of nonencapsulated dye was also higher in the DFG laser treated group vs the CO2 laser treated group after 48 h (p < 0.0001), while encapsulated dye was not detected in any group. CONCLUSION: The DFG laser treated skin exhibited significantly higher total fluorescence uptake compared to the CO2 laser. Additionally, the smaller spot size and thinner CZ of the DFG laser could result in faster wound healing and reduced adverse effects while delivering similar or greater amount of topically applied drugs.

Extracorporeal membrane oxygenators with light-diffusing fibers for treatment of carbon monoxide poisoning: Experiments, mathematical modeling, and performance assessment with unit cells.

BACKGROUND AND OBJECTIVES: Approximately 50,000 emergency department visits per year due to carbon monoxide (CO) poisoning occur in the United States alone. Tissue hypoxia can occur at very low CO concentration exposures because CO binds with a 250-fold higher affinity than oxygen to hemoglobin. The most effective therapy is 100% hyperbaric oxygen (HBO) respiration. However, there are only a limited number of cases with ready accessibility to the specialized HBO chambers. In previous studies, we developed an extracorporeal veno-venous membrane oxygenator that facilitates exposure of blood to an external visible light source to photo-dissociate carboxyhemoglobin (COHb) and significantly increase CO removal from CO-poisoned blood (photo-extracorporeal veno-venous membrane oxygenator [p-ECMO]). One objective of this study was to describe in vitro experiments with different laser wavelength sources to compare CO elimination rates in a small unit-cell ECMO device integrated with a light-diffusing optical fiber. A second objective was to develop a mathematical model that predicts CO elimination rates in the unit-cell p-ECMO  device design upon which larger devices can be based. STUDY DESIGN/MATERIAL AND METHODS: Two small unit-cell p-ECMO devices consisted of a plastic capillary with a length and inside diameter of 10 cm and 1.15 mm, respectively. Either five (4-1 device) or seven (6-1 device) gas exchange tubes were placed in the plastic capillary and a light-diffusing fiber was inserted into one of the gas exchange tubes. Light from lasers emitting either 635 nm or 465 nm wavelengths was coupled into the light-diffusing fiber as oxygen flowed through the gas exchange membranes. To assess the ability of the device to remove CO from blood in vitro, the percent COHb reduction in a single pass through the device was assessed with and without light. The Navier Stokes equations, Carreau-Yesuda model, Boltzman equation for light distribution, and hemoglobin kinetic rate equations, including photo-dissociation, were combined in a mathematical model to predict COHb elimination in the experiments. RESULTS: For the unit-cell devices, the COHb removal rate increases with increased 635 nm laser power, increased blood time in the device, and greater gas exchange membrane surface-to-blood volume ratio. The 6-1 device COHb half-life versus that of the 4-1 device with 4 W at 635 nm light was 1.5 min versus 4.25 min, respectively. At 1 W laser power, 635 nm and 465 nm exhibited similar CO removal rates. The COHb half-life times of the 6-1 device were 1.25, 2.67, and 8.5 min at 635 nm (4 W), 465 nm (1 W), and 100% oxygen only, respectively. The mathematical model predicted the experimental results. An analysis of the in vivo COHb half-life of oxygen respiration therapy versus an adjunct therapy with a p-ECMO device and oxygen respiration shows a reduction from 90 min to as low as 10 min, depending on the device design. CONCLUSION: In this study, we experimentally studied and developed a mathematical model of a small unit-cell ECMO device integrated with a light-diffusing fiber illuminated with laser light. The unit-cell device forms the basis for a larger device and, in an adjunct therapy with oxygen respiration, has the potential to remove COHb at much higher rates than oxygen therapy alone. The mathematical model can be used to optimize the design in practical implementations to quickly and efficiently remove CO from CO-poisoned blood.

Assessment of a 3050/3200 nm fiber laser system for ablative fractional laser treatments in dermatology.

BACKGROUND AND OBJECTIVES: Mid-infrared (IR) ablative fractional laser treatments are highly efficacious for improving the appearance of a variety of dermatological conditions such as photo-aged skin. However, articulated arms are necessary to transmit the mid-IR light to the skin, which restricts practicality and clinical use. Here, we have assessed and characterized a novel fiber laser-pumped difference frequency generation (DFG) system that generates ablative fractional lesions and compared it to clinically and commercially available thulium fiber, Erbium:YAG (Er:YAG), and CO2 lasers. MATERIALS AND METHODS: An investigational 20 W, 3050/3200 nm fiber laser pumped DFG system with a focused spot size of 91 µm was used to generate microscopic ablation arrays in ex vivo human skin. Several pulse energies (10-70 mJ) and pulse durations (2-14 ms) were applied and lesion dimensions were assessed histologically using nitro-blue tetrazolium chloride stain. Ablation depths and coagulative thermal damage zones were analyzed across three additional laser systems. RESULTS: The investigational DFG system-generated deep (>2 mm depth) and narrow (<100 µm diameter) ablative lesions surrounded by thermal coagulative zones of at least 20 µm thickness compared to 13, 40, and 320 µm by the Er:YAG, CO2 , and Thulium laser, respectively. CONCLUSION: The DFG system is a small footprint device that offers a flexible fiber delivery system for ablative fractional laser treatments, thereby overcoming the requirement of an articulated arm in current commercially available ablative lasers. The depth and width of the ablated microcolumns and the extent of surrounding coagulation can be controlled; this concept can be used to design new treatment procedures for specific indications. Clinical improvements and safety are not the subject of this study and need to be explored with in vivo clinical studies.

Preclinical comparison of superpulse thulium fiber laser and a holmium:YAG laser for lithotripsy.

PURPOSE: A superpulse (500 W peak power) thulium fiber laser operating at a 1940 nm wavelength, suitable for lithotripsy, has recently been developed. The goal of this study was to compare stone fragmentation and dusting performance of the prototype superpulse thulium fiber laser with leading commercially available, high-power holmium:YAG lithotripters (wavelength 2100 nm) in a controlled in vitro environment. METHODS: Two experimental setups were designed for investigating stone ablation rates and retropulsion effects, respectively. In addition, the ablation setup enabled water temperature measurements during stone fragmentation in the laser-stone interaction zone. Human uric acid (UA) and calcium oxalate monohydrate (COM) stones were used for ablation experiments, whereas standard BegoStone phantoms were utilized in retropulsion experiments. The laser settings were matched in terms of pulse energy, pulse repetition rate, and average power. RESULTS: At equivalent settings, thulium fiber laser ablation rates were higher than those for holmium:YAG laser in both dusting mode (threefold for COM stones and 2.5-fold for UA stones) and fragmentation mode (twofold for UA stones). For single-pulse retropulsion experiments, the threshold for onset of stone retropulsion was two to four times higher for thulium fiber laser. The holmium:YAG laser generated significantly stronger retropulsion effects at equal pulse energies. The water temperature elevation near the laser-illuminated volume did not differ between the two lasers. CONCLUSIONS: Distinctive features of the thulium fiber laser (optimal wavelength and long pulse duration) resulted in faster stone ablation and lower retropulsion in comparison to the holmium:YAG laser.

Peroxide dental bleaching via laser microchannels and tooth color measurements.

The aim of this study was to use microchannels drilled by an Er:YAG laser into a human tooth through the enamel into the dentin for direct injection of hydrogen peroxide (HP) to produce a minimally invasive, rapid, tooth bleaching effect. The experiments were conducted in vitro. Five microchannels with a diameter of ?200???m and a depth of ?2??mm were drilled through the palatal side of a human tooth crown using the microbeam of an Er:YAG-laser with a wavelength of 2.94???m. After injection of an aqueous solution of 31%-HP through the microchannels, the tooth color was evaluated using a VITA shade guide and International Commission on Illumination L*ab color parameters. A tooth model used for the evaluation of the distribution of HP concentration was created and the amount of HP which can be injected into tooth dentin to bleach it safely was estimated. Injection of 1.5±0.1??mm3 of 31%-HP into the tooth led to noticeable bleaching within 3 h and significant improvement of tooth color within 24 h.

Polarization enhanced wide-field imaging for evaluating dermal changes caused by non-ablative fractional laser treatment.

BACKGROUND AND OBJECTIVE: Laser non-ablative fractional treatment (NAFT) is an important part of armamentarium of modern dermatology. Recently, such treatments have become available in at-home setting due to advent of self-application NAFT devices. Safety and clinical efficacy of NAFT are well established in multiple studies. Less information is available on morphological and functional changes in tissue occurring as a result of NAFT. Polarization-enhanced multispectral wide-field imaging device allows for in vivo real time visualization of dermal structures. The objective of this study is to use this imaging modality to monitor early effects of the home-use NAFT on collagen networks. MATERIALS AND METHODS: Eight subjects (skin types I-III) used a commercially available NAFT device (wavelength 1410 nm, energy per pulse up to 15 mJ) to treat peri-orbital wrinkles in standard recommended mode, that is daily, for a period of two weeks. In each session, subjects applied a pre-treatment gel to the peri-orbital areas and then used the device, delivering 8-10 applications to each side of the face without overlap. Subjects were asked to use the highest device setting. Cross-polarized 440 nm wide-field images were acquired from peri-orbital areas before and two weeks after the onset of the treatment regimen. Wide-field images were normalized and thresholded to a level of 40% brightness to emphasize collagen structure. Collagen content was quantitatively determined from thresholded collagen images. Improvement in collagen content at two weeks of daily treatments was assessed. RESULTS: Eight subjects (age 24-53 years) completed the study. Cross-polarized 440 nm wide-field images clearly delineated collagen networks. Quantitative assessment of collagen images revealed statistically significant (P < 0.05) improvement of collagen content at a time point of two weeks. Seven out of eight subjects showed varying degree of improvement. The increase of collagen content in responders ranged from 1-26%, with the mean improvement of 11%. Subjects in their early 40s showed the best improvement in comparison to younger and older age groups. CONCLUSIONS: Polarization-enhanced multispectral wide-field reflectance imaging method is a suitable technique for noninvasive in vivo assessment of dermal structures. Post-treatment images, taken three days after the last treatment session, demonstrate that non-ablative fractional treatment resulted in increased dermal collagen content as measured by the polarization-enhanced technique as early as two weeks post onset of the treatments. However, further studies with a larger number of subjects and longer treatment period are required to determine the optimal regimen and how long the results will last.

Uncovering dental implants using a new thermo-optically powered (TOP) technology with tissue air-cooling.

BACKGROUND AND OBJECTIVES: Uncovering implants with lasers, while bloodless, has been associated with a risk of implant and bone overheating. The present study evaluated the effect of using a new generation of high-power diode lasers on the temperature of a dental implant and the surrounding tissues using an in vitro model. STUDY DESIGN/MATERIALS AND METHODS: The implant temperature was measured at three locations using micro thermocouples. Collateral thermal damage of uncovered soft tissues was evaluated using NTBC stain. Implant temperature rise during and collateral thermal soft-tissue damage following implant uncovering with and without tissue air-cooling was studied using both the classic operational mode and the new thermo-optically powered (TOP) technology. RESULTS: For the classic surgical mode using a cork-initiated tip and constant laser power set at 3.4 W, the maximum temperature rise in the coronal and apical parts of the implant was 23.2 ± 4.1°Ð¡ and 9.5 ± 1.8°Ð¡, respectively, while 1.5 ± 0.5 mm of collateral thermal damage of the soft tissue surrounding the implant model occurred. Using the TOP surgical tip with constant laser power reduced implant overheating by 30%; collateral thermal soft-tissue damage was 0.8 ± 0.2 mm. Using the TOP surgical mode with a tip temperature setting of 800°C and air-cooling reduced the implant temperature rise by more than 300%, and only 0.2 ± 0.1 mm of collateral thermal soft-tissue damage occurred, typical for optimized CO2 laser surgery. Furthermore, use of the new generation diode technology (TOP surgical mode) appeared to reduce the time required for implant uncovering by a factor of two, compared to the standard surgical mode. CONCLUSIONS: Use of the new generation diode technology (TOP surgical mode) may significantly reduce overheating of dental implants during uncovering and seems to be safer for the adjacent soft and hard tissues. Use of such diode lasers with air-cooling can radically reduce the rise in implant temperatures (by more than three times), potentially making this technology safe and effective for implant uncovering.

Transcutaneous delivery of micro- and nanoparticles with laser microporation.

Fractional laser ablation is one of the relatively safe and minimally invasive methods used to administer micro- and nanoparticles into the skin at sufficiently large depth. In this article, we present the results of delivery of TiO2 nanoparticles and Al2O3 microparticles into skin. Fractional laser microablation of skin was provided by a system based on a pulsed Er:YAG laser with the following parameters: the wavelength 2940 nm, the pulse energy 3.0 J, and the pulse duration 20 ms. Ex vivo and in vivo human skin was used in the study. The suspensions of titanium dioxide and alumina powder in polyethylene glycol with particle size of about 100 nm and 27 µm, respectively, were used. In the ex vivo experiments, reflectance spectra of skin samples with administered particles were measured and histological sections of the samples were made. In the in vivo experiment, reflectance spectroscopy, optical coherence tomography, and clinical photography were used to monitor the skin status during one month after suspension administering. It is shown that particles can be delivered into dermis up to the depth 230 µm and distributed uniformly in the tissue. Spectral measurements confirm that the particles stay in the dermis longer than 1 month.

Fat tissue histological study at indocyanine green-mediated photothermal/photodynamic treatment of the skin in vivo.

Histological slices of skin samples with the subcutaneous adipose tissue after photothermal/photodynamic treatment are analyzed. In the case of subcutaneous indocyanine green injection and 808-nm diode laser exposure of the rat skin site in vivo, the greatest changes in tissue condition were observed. Processes were characterized by dystrophy, necrosis, and desquamation of the epithelial cells, swelling and necrosis of the connective tissue, and widespread necrosis of the subcutaneous adipose tissue. The obtained data are useful for safe layer-by-layer dosimetry of laser illumination of ICG-stained adipose tissue for treatment of obesity and cellulite.

Characterization of an optimized light source and comparison to pulsed dye laser for superficial and deep vessel clearance.

BACKGROUND AND OBJECTIVE: An arc lamp-based device providing optimized spectrum and pulse shape was characterized and compared with two pulsed dye laser (PDL) systems using a vascular phantom. Safety and effectiveness for facial telangiectasia are presented in clinical case studies. STUDY DESIGN/MATERIALS AND METHODS: An optimized pulsed light source's (OPL) spectral and power output were characterized and compared with two 595 nm PDL devices. Purpuric threshold fluences were determined for the OPL and PDLs on Fitzpatrick type II normal skin. A vascular phantom comprising blood-filled quartz capillaries beneath porcine skin was treated by the devices at their respective purpuric threshold fluences for 3 ms pulse widths, while vessel temperatures were monitored with an infrared (IR) camera. Patients with Fitzpatrick skin types II-III received a split-face treatment with the OPL and a 595 nm PDL. RESULTS: The OPL provided a dual-band output spectrum from 500 to 670 nm and 850-1,200 nm, pulse widths from 3 to 100 ms, and fluences to 80 J/cm(2). The smooth output power measured during all pulse widths provides unambiguous vessel size selectivity. Percent energy in the near infra-red increased with decreasing output power from 45% to 60% and contributed 15-26% to heating of deep vessels, respectively. At purpuric threshold fluences the ratio of OPL to PDL vessel temperature rise was 1.7-2.8. OPL treatments of facial telangiectasia were well-tolerated by patients demonstrating significant improvements comparable to PDL with no downtime. CONCLUSIONS: Intense pulsed light (IPL) and PDL output pulse and spectral profiles are important for selective treatment of vessels in vascular lesions. The OPL's margin between purpuric threshold fluence and treatment fluence for deeper, larger vessels was greater than the corresponding margin with PDLs. The results warrant further comparison studies with IPLs and other PDLs.

Evaluation of a fractional laser with optical compression pins.

BACKGROUND AND OBJECTIVE: Non-ablative fractional lasers have been used in skin rejuvenation procedures with some success. In general, the optimum area coverage and depths of the fractional thermal injury zones depend on the specific indications of interest. For all fractional devices, depth is adjusted with energy that also determines the coagulation area at the dermal/epidermal junction. Micro-beams (µB) of a 1,540 nm laser are co-aligned with optical pins in a device designed to provide skin compression during treatment to remodel the deeper reticular dermis and hypodermis while minimizing epidermal damage. The device is characterized in ex vivo and clinical studies. MATERIALS AND METHODS: Ex vivo porcine skin was treated with a compression-pins optic connected to an Er:Glass laser hand piece. Nitroblue tetrazolium chloride (NBTC) cell viability staining of horizontal radial and vertical sections of post-treatment skin was used to assess coagulation profiles. A pilot clinical study was also performed to evaluate the effects of compression on epidermal injury. RESULTS: The compression-pins optic provided deeper coagulation to 1.5 mm depths and less epidermal injury than without compression. Coagulation depth was increased further with stacked pulses. CONCLUSION: The ability to de-couple depth of treatment from area coverage provides greater flexibility of treatments. The results promise greater possibilities to vary dermal injury patters which may offer increased benefit in treating a variety of cutaneous conditions.

The role of laser tunnels in laser-assisted lipolysis.

BACKGROUND AND OBJECTIVES: Laser-assisted lipolysis (LAL) devices are used as adjuncts to liposuction that create laser tunnels to heat the adipose and connective tissue. Available systems vary significantly across choice of wavelengths, power delivery, and tip design. Rationale are developed for optimum laser parameters evaluated with physical principles and in controlled ex vivo tests. STUDY DESIGN/MATERIALS AND METHODS: A computer model for radiation propagation, thermal conduction and coagulation was developed to study laser tunnels formed in human adipose tissue. An ex vivo study with porcine tissue compared laser tunnels created by a device that operates in short-pulse mode with a 0.6 mm diameter fiber emitting lipid non-selective laser wavelengths to a device that operates in continuous-wave (CW) mode with a 1.5 mm diameter fiber emitting lipid- and water-selective laser wavelengths. RESULTS: Photothermolytic heating is the optimum mechanism to control delivery of heat to the tissue. Fiber tip surface power density can be optimized for ease of penetration and good volumetric heating while avoiding extremely high peak temperatures. CW rather than pulsed laser emission also minimizes peak temperature rise that can interfere with tunnel formation. Lipid- or water-selective laser wavelengths with low absorption yield lower peak temperatures and more uniform volume heating, while lipid-selective wavelengths offer greater safety near the dermis. Ex vivo histology demonstrated greater volumetric heating with the CW, lipid-selective device at similar power settings. CONCLUSION: Wavelength, power delivery, and tip design are based on physical principles and together with treatment technique laser tunnel dimensions can be optimized as confirmed in ex vivo histology. The resulting thermal zones provide ease of penetration through adipose tissue and enable treatment uniformity. Based upon principles of fractional skin treatment the thermal zones induce healing responses in adipose tissue with potential to enhance clinical efficacy.

Semi-Automated method of analysis of horizontal histological sections of skin for objective evaluation of fractional devices.

BACKGROUND AND OBJECTIVE: The treatment of skin with fractional devices creates columns of micro-ablation or micro-denaturation depending on the device. Since the geometric profiles of thermal damage depend on the treatment parameters or physical properties of the treated tissue, the size of these columns may vary from a few microns to a few millimeters. For objective evaluation of the damage profiles generated by fractional devices, this report describes an innovative and efficient method of processing and evaluating horizontal sections of skin using a novel software program. MATERIALS AND METHODS: Ex vivo porcine skin was treated with the Lux1540/10, Lux1540 Zoom and Lux2940 with 500 optics. Horizontal (radial) sections of biopsies were obtained and processed with H&E and NBTC staining. Digital images of the histologic sections were taken in either transmission or reflection illumination and were processed using the SAFHIR program. RESULTS: NBTC- and H&E-stained horizontal sections of ex vivo skin treated with ablative and non-ablative fractional devices were obtained. Geometric parameters, such as depth, diameter, and width of the coagulated layer (if applicable), and micro-columns of thermal damage, were evaluated using the SAFHIR software. The feasibility of objective comparison of the performance of two different fractional devices was demonstrated. CONCLUSION: The proposed methodology provides a comprehensive, objective, and efficient approach for the comparison of various fractional devices. Correlation of device settings with the objective dimensions of post-treatment damage profiles serve as a powerful tool for the prediction and modulation of clinical response.

Pilot investigation of the correlation between histological and clinical effects of infrared fractional resurfacing lasers.

METHODS: Yucatan Black pig skin was treated with a 1,540-nm erbium (Er):glass laser (Lux1540, 15 and 30 mJ) and two 1,550-nm Er-doped fiber lasers (Fraxel SR750 and SR1500, 8, 10, and 12 mJ). Histologic sections were examined to determine the depth of damage and to correlate subjects' clinical response. Concurrently, six subjects with photodamaged skin received three split-face and ipsilateral dorsal hand treatments with the 1,540-nm Er:glass laser on one side and one of the 1,550-nm Er-doped lasers (Fraxel SR750) on the other. RESULTS: The 1,550-nm Er-doped lasers, using lower fluences and higher densities, produced shallower micro-columns than the 1,540-nm Er:glass device at higher fluences and lower densities (mean depths 250-275 microm vs 425-525 microm, respectively). Blinded assessors found greater overall improvement in pigmentation with the 1,550-nm Er-doped laser and better overall improvement in texture with the 1,540-nm Er:glass laser. CONCLUSIONS: Greater densities of shallower damage columns at lower energies may better improve pigmentation, whereas deeper injuries, using higher energies and moderate densities, may better improve texture. This pilot study did not compare similar fluences and histologic damage between the two systems, and newer available systems allow for greater depth of penetration.

Optical clearing of human skin: comparative study of permeability and dehydration of intact and photothermally perforated skin.

Accelerated diffusion of water and hyperosmotic optical clearing agents is studied as a result of enhanced epidermal permeability. A lattice of microzones (islets) of damage in stratum corneum is induced using a flash-lamp applique system. An optical clearing agent composed of 88% glycerol in aqueous solution is used for all experiments. Research of skin dehydration and glycerol delivery through epidermis at both intact and perforated stratum corneum is presented. The dehydration process induced by both stimuli of evaporation and osmotic agent action is studied by weight measurements. Dynamics of refractive index alteration of both glycerol solution and water during their interaction with skin samples is monitored. The amounts of water escaping from skin through the stratum corneum, due to hyperosmotic-agent action, and glycerol penetrating through the skin sample, are estimated. The results show that the proposed method allows for effective transepidermal water loss and delivery of optical clearing agents.

Micro-fractional ablative skin resurfacing with two novel erbium laser systems.

BACKGROUND AND OBJECTIVES: Fractional ablation offers the potential benefits of full-surface ablative skin resurfacing while minimizing adverse effects. The purpose of this study was to evaluate the safety, damage profile, and efficacy of erbium fractional lasers. MATERIALS AND METHODS: Histology from animal and human skin as well as clinical evaluations were conducted with erbium YAG (2,940 nm) and erbium YSGG (2,790 nm) fractional lasers varying pulse width, microbeam (microb) energy, number of passes, and stacking of pulses. RESULTS: Single-pulse treatment parameters from 1 to 12 mJ per 50-70 microm diameter microbeam and 0.25-5 milliseconds pulse widths produced microcolumns of ablation with border coagulation of up to 100 microm width and 450 microm depth. Stacking of pulses generated deeper microcolumns. Clinical observations and in vivo histology demonstrate rapid re-epithelization and limited adverse side effects. Facial treatments were performed in the periorbital and perioral areas using 1-8 passes of single and stacked pulses. Treatments were well-tolerated and subjects could resume their normal routine in 4 days. A statistically significant reduction in wrinkle scores at 3 months was observed for both periorbital and perioral wrinkles using blinded grading. For periorbital treatments of four passes or more, over 90% had > or =1 score wrinkle reduction (0-9 scale) and 42% had > or =2. For perioral wrinkles, over 50% had substantial improvements (> or =2). CONCLUSION: The clinical observations and histology findings demonstrate that micro-fractional ablative treatment with 2,790 and 2,940 nm erbium lasers resulted in safe and effective wrinkle reduction with minimal patient downtime. The depth and width of the ablated microcolumns and varying extent of surrounding coagulation can be controlled and used to design new treatment procedures targeted for specific indications and areas such as moderate to severe rhytides and photodamaged skin.

Intense pulsed light and laser treatment of facial telangiectasias and dyspigmentation: some theoretical and practical comparisons.

BACKGROUND AND OBJECTIVE: A comparative overview is presented, both theoretical and clinical, for intense pulsed light (IPL) and laser treatment of facial telangiectasias and pigmented lesions. MATERIALS AND METHODS: A narrative approach describes light penetration into the epidermis, dermis, dermal-epidermal junction, and facial ectasias. Based on mathematical models, we examine some temperature profiles for monochromatic and broadband light sources. Specifically, temperature elevations of representative vascular targets are discussed. Also, clinical scenarios are reviewed for both IPL and laser. Although multiple monochromatic devices are reviewed, only the 532 and 595 nm wavelengths are emphasized. RESULTS: In theory, an IPL can be filtered to simulate 532 and 595 nm laser light in the treatment of telangiectasias and dyschromias. In comparing our experiences with the different devices, all three (IPL, 532 nm laser, and 595 nm laser) are capable of achieving a reduction in ectasias and hyperpigmented macules. CONCLUSIONS: With an optimal set of parameters, IPLs and lasers are comparable in the treatment of vascular and pigmented lesions with respect to treatment efficiency and safety.

Low-intensity indocyanine-green laser phototherapy of acne vulgaris: pilot study.

Near infrared (NIR) diode laser low-intensity (soft) phototherapy with the topical application of indocyanine green (ICG) has been suggested for treatment of acne vulgaris. Twelve volunteers with acne lesions on their faces and/or backs were enrolled in the experiment. Skin areas of the subjects that were 4 x 5 cm2 were stained with ICG solution for 5 min before laser irradiation (803 nm) at a power density up to 50 mW/cm2 for 5 to 10 min. For 75% of the subjects, a single treatment was provided and for the other 25%, eight sequential treatments over a period of a month were carried out. Observations a month after the completion of the treatment showed that only the multiple treatments with a combination of ICG and NIR irradiation reduced inflammation and improved the state of the skin for a month without any side effects. A month after treatment, the improvement was about 80% for the group receiving multiple treatments. Single treatments did not have a prolonged effect.

A pilot study of ICG laser therapy of acne vulgaris: photodynamic and photothermolysis treatment.

BACKGROUND AND OBJECTIVES: The near-infrared (NIR) laser radiation due to its high penetration depth is widely used in phototherapy. In application to skin appendages, a high selectivity of laser treatment is needed to prevent light action on surrounding tissues. Indocyanine green (ICG) dye may provide a high selectivity of treatment due to effective ICG uploading by a target and its narrow band of considerable absorption just at the wavelength of the NIR diode laser. The goal of this study is to demonstrate the efficacy of the NIR diode laser phototherapy in combination with topical application of ICG suggested for soft and thermal treatment of acne vulgaris. STUDY DESIGN/MATERIALS AND METHODS: Twenty-two volunteers with facile or back-located acne were enrolled. Skin sites of subjects were stained by ICG and irradiated by NIR laser-diode light (803 or 809 nm). One mg/ml solution of ICG was applied for 5 or 15 minutes to the cleaned skin site. Untreated, only stained and only light irradiated skin areas served as controls. For soft acne treatment, the low-intensity (803 nm, 10-50 mW/cm(2), 5-10 minutes) or the medium-intensity (809 nm, 150-190 mW/cm(2), 15 minutes) protocols were used. The single and multiple (up to 8-9) treatments were provided. The individual acne lesions were photothermally treated at 18 W/cm(2) (803 nm, 0.5 seconds) without skin surface cooling or at 200 W/cm(2) (809 nm, 0.5 seconds) with cooling. RESULTS: The observations during 1-2 months showed that soft acne treatment decreased the number of active elements, reduced erythema and inflammation, and considerably improved the skin state without any side effects. At high power densities (up to 200 W/cm(2)), ICG stained acne inflammatory elements were destroyed for light exposures of 0.5 seconds. CONCLUSIONS: Based on the concept that hair follicle, especially sebaceous gland, can be intensively and selectively stained by ICG due to dye diffusion through pilosebaceous canal and its fast uptake by living microorganisms, by vital keratinocytes of epithelium of the canal and sebaceous duct, and by rapidly proliferating sebocytes, new technologies of soft and thermal acne lesions treatment that could be used in clinical treatment of acne were proposed.

In vitro and in vivo study of dye diffusion into the human skin and hair follicles.

We present experimental results on the in vitro and in vivo study of dye diffusion into human skin and hair follicles. We have studied some commercially available dyes for potential using in the laser selective thermolysis. The degree and the depth of hair follicle dyeing inside the skin were determined. For hairs in different stages the sebaceous gland was stated as a reservoir for a dye administration. It was found that the penetration depth of dyes is about 1.2 mm from the skin surface. We have developed the biocompatible Indocyanine Green lotions and the method for in vivo dyeing and dye in depth monitoring. Shift on 16-21 nm of absorption peak of Indocyanine Green to the longer wavelengths due to Indocyanine Green binding with cell proteins in the human skin was found.