Noninvasive treatment of cutaneous neurofibromas (cNFs): Results of a randomized prospective, direct comparison of four methods.

BACKGROUND: People with Neurofibromatosis Type 1 (NF1) suffer disfigurement and pain when hundreds to thousands of cutaneous neurofibromas (cNFs) appear and grow throughout life. Surgical removal of cNFs under anesthesia is the only standard therapy, leaving surgical scars. OBJECTIVE: Effective, minimally-invasive, safe, rapid, tolerable treatment(s) of small cNFs that may prevent tumor progression. METHODS: Safety, tolerability, and efficacy of 4 different treatments were compared in 309, 2-4 mm cNFs across 19 adults with Fitzpatrick skin types (FST) I-IV: radiofrequency (RF) needle coagulation, 755 nm alexandrite laser with suction, 980 nm diode laser, and intratumoral injection of 10 mg/mL deoxycholate. Regional pain, clinical responses, tumor height and volume (by 3D photography) were assessed before, 3 and 6 months post-treatment. Biopsies were obtained electively at 3 months. RESULTS: There was no scarring or adverse events > grade 2. Each modality significantly (P < .05) reduced or cleared cNFs, with large variation between tumors and participants. Alexandrite laser and deoxycholate were fast and least painful; 980 nm laser was most painful. Growth of cNFs was not stimulated by treatment(s) based on height and volume values at 3 and 6 months compared to baseline. LIMITATIONS: Intervention was a single treatment session; dosimetry has not been optimized. CONCLUSIONS: Small cNFs can be rapidly and safely treated without surgery.

Vitamin K3 (Menadione) is a multifunctional microbicide acting as a photosensitizer and synergizing with blue light to kill drug-resistant bacteria in biofilms.

Cutaneous bacterial wound infections typically involve gram-positive cocci such as Staphylococcus aureus (SA) and usually become biofilm infections. Bacteria in biofilms may be 100-1000-fold more resistant to an antibiotic than the clinical laboratory minimal inhibitory concentration (MIC) for that antibiotic, contributing to antimicrobial resistance (AMR). AMR is a growing global threat to humanity. One pathogen-antibiotic resistant combination, methicillin-resistant SA (MRSA) caused more deaths globally than any other such combination in a recent worldwide statistical review. Many wound infections are accessible to light. Antimicrobial phototherapy, and particularly antimicrobial blue light therapy (aBL) is an innovative non-antibiotic approach often overlooked as a possible alternative or adjunctive therapy to reduce antibiotic use. We therefore focused on aBL treatment of biofilm infections, especially MRSA, focusing on in vitro and ex vivo porcine skin models of bacterial biofilm infections. Since aBL is microbicidal through the generation of reactive oxygen species (ROS), we hypothesized that menadione (Vitamin K3), a multifunctional ROS generator, might enhance aBL. Our studies suggest that menadione can synergize with aBL to increase both ROS and microbicidal effects, acting as a photosensitizer as well as an ROS recycler in the treatment of biofilm infections. Vitamin K3/menadione has been given orally and intravenously worldwide to thousands of patients. We conclude that menadione/Vitamin K3 can be used as an adjunct to antimicrobial blue light therapy, increasing the effectiveness of this modality in the treatment of biofilm infections, thereby presenting a potential alternative to antibiotic therapy, to which biofilm infections are so resistant.

Optical, flow, and thermal analysis of a phototherapy extracorporeal membrane oxygenator for treating carbon monoxide poisoning.

BACKGROUND: Extracorporeal membrane oxygenators (ECMO) are currently utilized to mechanically ventilate blood when lung or lung and heart function are impaired, like in cases of acute respiratory distress syndrome (ARDS). ARDS can be caused by severe cases of carbon monoxide (CO) inhalation, which is the leading cause of poison-related deaths in the United States. ECMOs can be further optimized for severe CO inhalation using visible light to photo-dissociate CO from hemoglobin (Hb). In previous studies, we combined phototherapy with an ECMO to design a photo-ECMO device, which significantly increased CO elimination and improved survival in CO-poisoned animal models using light at 460, 523, and 620 nm wavelengths. Light at 620 nm was the most effective in removing CO. OBJECTIVE: The aim of this study is to analyze the light propagation at 460, 523, and 620 nm wavelengths and the 3D blood flow and heating distribution within the photo-ECMO device that increased CO elimination in CO-poisoned animal models. METHODS: Light propagation, blood flow dynamics, and heat diffusion were modeled using the Monte Carlo method and the laminar Navier-Stokes and heat diffusion equations, respectively. RESULTS: Light at 620 nm propagated through the device blood compartment (4 mm), while light at 460 and 523 nm only penetrated 48% to 50% (~2 mm). The blood flow velocity in the blood compartment varied with regions of high (5 mm/s) and low (1 mm/s) velocity, including stagnant flow. The blood temperatures at the device outlet for 460, 523, and 620 nm wavelengths were approximately 26.7°C, 27.4°C, and 20°C, respectively. However, the maximum temperatures within the blood treatment compartment rose to approximately 71°C, 77°C, and 21°C, respectively. CONCLUSIONS: As the extent of light propagation correlates with efficiency in photodissociation, the light at 620 nm is the optimal wavelength for removing CO from Hb while maintaining blood temperatures below thermal damage. Measuring the inlet and outlet blood temperatures is not enough to avoid unintentional thermal damage by light irradiation. Computational models can help eliminate risks of excessive heating and improve device development by analyzing design modifications that improve blood flow, like suppressing stagnant flow, further increasing the rate of CO elimination.

Local vasoregulative interventions impact drug concentrations in the skin after topical laser-assisted delivery.

INTRODUCTION: The ability of ablative fractional lasers (AFL) to enhance topical drug uptake is well established. After AFL delivery, however, drug clearance by local vasculature is poorly understood. Modifications in vascular clearance may enhance AFL-assisted drug concentrations and prolong drug dwell time in the skin. Aiming to assess the role and modifiability of vascular clearance after AFL-assisted delivery, this study examined the impact of vasoregulative interventions on AFL-assisted 5-fluorouracil (5-FU) concentrations in in vivo skin. METHODS: 5-FU uptake was assessed in intact and AFL-exposed skin in a live pig model. After fractional CO2 laser exposure (15 mJ/microbeam, 5% density), vasoregulative intervention using topical brimonidine cream, epinephrine solution, or pulsed dye laser (PDL) was performed in designated treatment areas, followed by a single 5% 5-FU cream application. At 0, 1, 4, 48, and 72 h, 5-FU concentrations were measured in 500 and 1500 µm skin layers by mass spectrometry (n = 6). A supplemental assessment of blood flow following AFL ± vasoregulation was performed using optical coherence tomography (OCT) in a human volunteer. RESULTS: Compared to intact skin, AFL facilitated a prompt peak in 5-FU delivery that remained elevated up to 4 hours (1500 µm: 1.5 vs. 31.8 ng/ml [1 hour, p = 0.002]; 5.3 vs. 14.5 ng/ml [4 hours, p = 0.039]). However, AFL's impact was transient, with 5-FU concentrations comparable to intact skin at later time points. Overall, vasoregulative intervention with brimonidine or PDL led to significantly higher peak 5-FU concentrations, prolonging the drug's dwell time in the skin versus AFL delivery alone. As such, brimonidine and PDL led to twofold higher 5-FU concentrations than AFL alone in both skin layers by 1 hour (e.g., 500 µm: 107 ng/ml [brimonidine]; 96.9 ng/ml [PDL], 46.6 ng/ml [AFL alone], p ≤ 0.024), and remained significantly elevated at 4 hours (p ≤ 0.024). A similar pattern was observed for epinephrine, although trends remained nonsignificant (p ≥ 0.09). Prolonged 5-FU delivery was provided by PDL, resulting in sustained drug deposition compared to AFL alone at both 48 and 72 hours in the superficial skin layer (p ≤ 0.024). Supporting drug delivery findings, OCT revealed that increases in local blood flow after AFL were mitigated in test areas also exposed to PDL, brimonidine, or epinephrine, with PDL providing the greatest, sustained reduction in flow over 48 hours. CONCLUSION: Vasoregulative intervention in conjunction with AFL-assisted delivery enhances and prolongs 5-FU deposition in in vivo skin.

Hyperbaric phototherapy augments blood carbon monoxide removal.

BACKGROUND AND OBJECTIVES: Carbon monoxide (CO) poisoning is responsible for nearly 50,000 emergency department visits and 1200 deaths per year. Compared to oxygen, CO has a 250-fold higher affinity for hemoglobin (Hb), resulting in the displacement of oxygen from Hb and impaired oxygen delivery to tissues. Optimal treatment of CO-poisoned patients involves the administration of hyperbaric 100% oxygen to remove CO from Hb and to restore oxygen delivery. However, hyperbaric chambers are not widely available and this treatment requires transporting a CO-poisoned patient to a specialized center, which can result in delayed treatment. Visible light is known to dissociate CO from carboxyhemoglobin (COHb). In a previous study, we showed that a system composed of six photo-extracorporeal membrane oxygenation (ECMO) devices efficiently removes CO from a large animal with CO poisoning. In this study, we tested the hypothesis that the application of hyperbaric oxygen to the photo-ECMO device would further increase the rate of CO elimination. STUDY DESIGN/MATERIAL AND METHODS: We developed a hyperbaric photo-ECMO device and assessed the ability of the device to remove CO from CO-poisoned human blood. We combined four devices into a "hyperbaric photo-ECMO system" and compared its ability to remove CO to our previously described photo-ECMO system, which was composed of six devices ventilated with normobaric oxygen. RESULTS: Under normobaric conditions, an increase in oxygen concentration from 21% to 100% significantly increased CO elimination from CO-poisoned blood after a single pass through the device. Increased oxygen pressure within the photo-ECMO device was associated with higher exiting blood PO2 levels and increased CO elimination. The system of four hyperbaric photo-ECMO devices removed CO from 1 L of CO-poisoned blood as quickly as the original, normobaric photo-ECMO system composed of six devices. CONCLUSION: This study demonstrates the feasibility and efficacy of using a hyperbaric photo-ECMO system to increase the rate of CO elimination from CO-poisoned blood. This technology could provide a simple portable emergency device and facilitate immediate treatment of CO-poisoned patients at or near the site of injury.

Fractional Ablative Laser Therapy is an Effective Treatment for Hypertrophic Burn Scars: A Prospective Study of Objective and Subjective Outcomes.

OBJECTIVE: The aim of this study is to determine objective and subjective changes in mature hypertrophic burn scars treated with a fractional ablative carbon dioxide (CO2) laser. BACKGROUND: Fractional CO2 laser treatment has been reported to improve burn scars, with increasing clinical use despite a paucity of controlled, prospective clinical studies using objective measures of improvement. METHODS: A multicenter, site-controlled, prospective open-label study was conducted from 2013 to 2016. Objective and patient-reported outcome measures were documented at baseline, at each monthly laser treatment, and 6 months after treatment. Objective measurements employed were: mechanical skin torque to measure viscoelastic properties; ultrasonic imaging to measure scar thickness; and reflectometry to measure erythema and pigmentation. Subjective measures included health-related quality of life, patient and investigator scar assessment scales, and blinded scoring of before and after photographs. Subjects aged 11 years or older with hypertrophic burn scars were recruited. Each subject received 3 monthly treatment sessions with an ablative fractionated CO2 laser. RESULTS: Twenty-nine subjects were enrolled, of whom 26 received at least 1 fractional CO2 laser treatment and 22 received 3 treatments. Mean age of those completing all 3 treatments was 28 years. Statistically significant objective improvements in elastic stretch (P < 0.01), elastic recovery (P < 0.01), extensibility (P < 0.01), and thickness (P < 0.01) were noted. Patient- and physician-reported scar appearance and pain/pruritus were significantly improved (P < 0.01). There was no regression of improvement for at least 6 months after treatment. CONCLUSIONS: Fractional ablative laser treatment provides significant, sustained improvement of elasticity, thickness, appearance, and symptoms of mature hypertrophic burn scars.

A crosslinked polymer skin barrier film for moderate to severe atopic dermatitis: A pilot study in adults.

BACKGROUND: Occlusive treatments are a mainstay in atopic dermatitis (AD) management but may not be well tolerated or lack compliance. A comfortable, semiocclusive, artificial skin barrier that is well tolerated, provides protection, and reduces water loss is needed. OBJECTIVE: To evaluate the potential tolerability and therapeutic benefits of a crosslinked polymer layer (XPL) in adults with AD. METHODS: A single-center, open-label pilot study was conducted involving 10 subjects with moderate to severe AD. Subjects applied XPL up to twice daily for 30 days on a selected treatment area. Investigator's Global Assessment, clinical signs of eczema, and pruritus were assessed on days 1, 3, 5, 15, and 30. Film durability and patient satisfaction were also evaluated. RESULTS: Investigator's Global Assessment scores improved from moderate to severe at baseline to clear to almost clear in 8 of 9 patients at day 30. Pruritus improved from trace to severe itching (baseline) to all subjects having trace to no itching at day 30. There was 1 adverse event of mild exudative dermatitis. LIMITATIONS: The study was limited by small sample size, open-label design, and lack of control. CONCLUSION: XPL may be an effective adjuvant in AD treatment. A larger study with a control group is warranted.

Phototherapy and extracorporeal membrane oxygenation facilitate removal of carbon monoxide in rats.

Inhaled carbon monoxide (CO) displaces oxygen from hemoglobin, reducing the capacity of blood to carry oxygen. Current treatments for CO-poisoned patients involve administration of 100% oxygen; however, when CO poisoning is associated with acute lung injury secondary to smoke inhalation, burns, or trauma, breathing 100% oxygen may be ineffective. Visible light dissociates CO from hemoglobin. We hypothesized that the exposure of blood to visible light while passing through a membrane oxygenator would increase the rate of CO elimination in vivo. We developed a membrane oxygenator with optimal characteristics to facilitate exposure of blood to visible light and tested the device in a rat model of CO poisoning, with or without concomitant lung injury. Compared to ventilation with 100% oxygen, the addition of extracorporeal removal of CO with phototherapy (ECCOR-P) doubled the rate of CO elimination in CO-poisoned rats with normal lungs. In CO-poisoned rats with acute lung injury, treatment with ECCOR-P increased the rate of CO removal by threefold compared to ventilation with 100% oxygen alone and was associated with improved survival. Further development and adaptation of this extracorporeal CO photo-removal device for clinical use may provide additional benefits for CO-poisoned patients, especially for those with concurrent acute lung injury.

Lidocaine-induced potentiation of thermal damage in skin and carcinoma cells.

OBJECTIVE: Lidocaine acts as a local anesthetic by blocking transmembrane sodium channel permeability, but also induces the synthesis of heat shock proteins and sensitizes cells to hyperthermia. A previous study reported two cases of deep focal skin ulceration at points corresponding to depot local lidocaine injection sites after treatment with non-ablative fractional resurfacing and it was hypothesized that lidocaine had focally sensitized keratinocytes to the thermal damage of laser treatment. The objective of this study was to investigate whether lidocaine potentiates hyperthermia damage to both normal and cancerous skin cells using an in vitro model. METHODS: Normal skin cell lines (fibroblasts, keratinocytes), skin cancer cell lines (melanoma, basal cell carcinoma), and a mucosal cancer cell line (cervical carcinoma) were exposed to various concentrations of lidocaine (0-0.3%) with or without hyperthermia (37°C, 42°C). RESULTS: Compared to normal skin cells, we demonstrate that cancer cell lines show significantly increased cell toxicity when a moderate temperature (42°C) and low lidocaine concentrations (0.1-0.2%) are combined. The toxicity directly correlates with a higher percentage of cells in S-phase (28-57%) in the cancer cell lines compared to normal skin cell lines (13-19%; R-square 0.6752). CONCLUSION: These results suggest that lidocaine potentiates thermal sensitivity of cell cycle active skin cells. The direct correlation between cell toxicity and S-phase cells could be harnessed to selectively treat skin and mucosal cancer cells while sparing the surrounding normal tissue. Additional research pre-clinically and clinically using several different heat sources (e.g., lasers, ultrasound, etc.) and lidocaine concentrations is needed to confirm and optimize these results. Lidocaine-enhanced hyperthermia may provide a non-invasive, alterative treatment option for highly proliferating, superficial skin, and mucosal lesions such as cancer or warts. Lasers Surg. Med. 51:88-94, 2019. © 2018 Wiley Periodicals, Inc.

Immediate skin responses to laser and light treatments: Warning endpoints: How to avoid side effects.

Lasers are versatile, commonly used treatment tools in dermatology. While it is tempting to follow manufacturer's guidelines or other "recipes" for laser treatment, this approach alone can be a recipe for disaster. Specific and immediate skin responses or endpoints exist and are clinically useful because they correlate with underlying mechanisms that are either desirable (ie, therapeutic), undesirable (ie, warning signs of injury or side effects), or incidental. The observation of clinical endpoints is a safe and reliable guide for appropriate treatment. This article presents the warning endpoints during specific dermatologic laser treatments, and the accompanying article presents the therapeutic endpoints, their underlying mechanisms, and the utility of these endpoints.

Immediate skin responses to laser and light treatments: Therapeutic endpoints: How to obtain efficacy.

Clinical endpoints are immediate or early tissue reactions that occur during laser treatment. They can guide the laser surgeon in delivering safe and effective laser treatment. Some endpoints act as warning signs of injury to the skin; others can indicate a therapeutic response. The first article in this series reviewed undesirable and warning endpoints, and this article focuses on desirable and therapeutic endpoints and their underlying mechanisms in laser surgery. We will also review treatments without clinical endpoints.

Translational medicine in the field of ablative fractional laser (AFXL)-assisted drug delivery: A critical review from basics to current clinical status.

BACKGROUND: Ablative fractional lasers enhance uptake of topical therapeutics and the concept of fractional laser-assisted drug delivery has now been taken into clinical practice. OBJECTIVES: We systematically reviewed preclinical data and clinical evidence for fractional lasers to enhance drug uptake and improve clinical efficacy. METHODS: We searched PubMed and Embase databases; 34 articles met the inclusion criteria. Studies were categorized into experimental preclinical studies and clinical trials, the latter graded according to level of evidence. RESULTS: All preclinical trials (n = 16) documented enhanced topical drug uptake into skin after ablative fractional laser treatment. Clinical evidence encompassed 18 studies, of which 9 were randomized controlled trials and 2 were controlled trials, examining neoplastic lesions, photodamaged skin, scars, onychomycosis, and topical anesthetics. The highest level of evidence was reached for actinic keratoses treated with methylaminolevulinate for photodynamic therapy (level IB, 5 randomized controlled trials), substantiating superior and long-lasting efficacy versus conventional photodynamic therapy. No adverse events were reported, but ablative fractional laser-assisted drug delivery implies risks of systemic drug absorption, especially when performed over large skin areas. CONCLUSIONS: Fractional laser-assisted drug delivery is beneficial in enhancing preclinical and clinical outcomes for certain skin conditions.

Temperature-Modulated Photodynamic Therapy for the Treatment of Actinic Keratosis on the Extremities: A One-Year Follow-up Study.

BACKGROUND: The efficacy of photodynamic therapy (PDT) using topical 5-aminolevulinic acid (ALA) for the treatment of actinic keratosis (AK) is lower on the distal extremities compared with head and neck areas. A recent pilot study demonstrated increased efficacy of ALA PDT when the skin is warmed during ALA incubation. Prolonged clearance rates on the heated extremity were noted in 3 subjects that were evaluated after the study ended. The aim of this study was to evaluate the longevity of clearance rates after temperature-modulated PDT for the treatment of AKs on the extremities. MATERIALS AND METHODS: A total of 18 subjects (20 pairs of extremities) with at least 10 AKs on the upper or lower extremities were enrolled in the single-center study. Twenty percent ALA was applied to both extremities and heated during the 1-hour incubation period, followed by exposure to 10 J/cm 417-nm blue light. Lesions were photographed, counted, and templated at baseline, 1 week, and 3, 6, 9, and 12 months after treatment. RESULTS: A total of 17 subjects completed the 1-year study. The total number of lesions counted at baseline was 724 Grade 1 and 2 AKs (median 15 on each extremity). The lesion count at 3 and 12 months was 70 (9.6%) and 72 (9.9%), respectively. Grade 3 AKs did not resolve with treatment. The median baseline temperature of the treated extremities was 31.6°C. The median maximum temperature during the 1-hour incubation period was 41.2°C. The median clearance at 3 months was 90% and the same was maintained at 12 months. No new AK lesions formed in the treated areas within the 12-month follow-up period. CONCLUSION: Warming the skin after application of ALA is well tolerated, does not increase side effects, and increases the long-term efficacy of PDT for the treatment of AKs. The authors suggest that mild skin warming may both improve efficacy and reduce variability of response to PDT in practice.

Pulmonary Phototherapy for Treating Carbon Monoxide Poisoning.

RATIONALE: Carbon monoxide (CO) exposure is a leading cause of poison-related mortality. CO binds to Hb, forming carboxyhemoglobin (COHb), and produces tissue damage. Treatment of CO poisoning requires rapid removal of CO and restoration of oxygen delivery. Visible light is known to effectively dissociate CO from Hb, with a single photon dissociating one CO molecule. OBJECTIVES: To determine whether illumination of the lungs of CO-poisoned mice causes dissociation of COHb from blood transiting the lungs, releasing CO into alveoli and thereby enhancing the rate of CO elimination. METHODS: We developed a model of CO poisoning in anesthetized and mechanically ventilated mice to assess the effects of direct lung illumination (phototherapy) on the CO elimination rate. Light at wavelengths between 532 and 690 nm was tested. The effect of lung phototherapy administered during CO poisoning was also studied. To avoid a thoracotomy, we assessed the effect of lung phototherapy delivered to murine lungs via an optical fiber placed in the esophagus. MEASUREMENTS AND MAIN RESULTS: In CO-poisoned mice, phototherapy of exposed lungs at 532, 570, 592, and 628 nm dissociated CO from Hb and doubled the CO elimination rate. Phototherapy administered during severe CO poisoning limited the blood COHb increase and improved the survival rate. Noninvasive transesophageal phototherapy delivered to murine lungs via an optical fiber increased the rate of CO elimination while avoiding a thoracotomy. CONCLUSIONS: Future development and scaling up of lung phototherapy for patients with CO exposure may provide a significant advance for treating and preventing CO poisoning.

Selective and localized radiofrequency heating of skin and fat by controlling surface distributions of the applied voltage: analytical study.

At low frequencies (hundreds of kHz to a few MHz), local energy absorption is proportional to the conductivity of tissue and the intensity of the internal electric field. At 1 MHz, the electric conductivity ratio between skin and fat is approximately 10; hence, skin would heat more provided the intensity of the electric field is similar in both tissues. It follows that selective and localized heat deposition is only feasible by varying electric fields locally. In this study, we vary local intensities of the internal electric field in skin, fat and muscle by altering its direction through modifying surface distributions of the applied voltage. In addition, we assess the long-term effects of these variations on tissue thermal transport. To this end, analytical solutions of the electric and bioheat equations were obtained using a regular perturbation method. For voltage distributions given by second- and eight-degree functions, the power absorption in fat is much greater than in skin by the electrode center while the opposite is true by the electrode edge. For a sinusoidal function, the absorption in fat varies laterally from greater to lower than in skin, and then this trend repeats from the center to the edge of the electrode. Consequently, zones of thermal confinement selectively develop in the fat layer. Generalizing these functions by parametrization, it is shown that radiofrequency (RF) heating of layered tissues can be selective and precisely localized by controlling the spatial decay, extent and repetition of the surface distribution of the applied voltage. The clinical relevance of our study is to provide a simple, non-invasive method to spatially control the heat deposition in layered tissues. By knowing and controlling the internal electric field, different therapeutic strategies can be developed and implemented.

Treatment of burn scars with the 1,550 nm nonablative fractional Erbium Laser.

BACKGROUND: Scarring is a major source of morbidity in patients with burns. Burn scars are difficult to treat and are among the worst scars seen in clinical medicine. Fractional laser resurfacing is a promising treatment option because of its unique wound healing response and depth of penetration. OBJECTIVE: To evaluate the efficacy of nonablative fractional resurfacing as a therapeutic option for extensive cutaneous scarring in burn patients. METHODS: Prospective, single-arm, pilot study. Ten subjects with second and third degree burn scars were treated with five nonablative fractional resurfacing treatments given at 4-week intervals. Three independent investigators evaluated subject outcomes at 3 months post-treatment (primary outcome); patients also provided subjective assessments of improvement (secondary outcome). RESULTS: Nonablative fractional resurfacing resulted in overall improvement in 90% of subjects, as determined by independent investigators; improvements were moderate to excellent in 60%. Ninety percent of subjects had improved skin texture, 80% had improved dyschromia, and 80% had improved hypertrophy/atrophy. Patients' self-reports also revealed moderate to excellent improvements (on average) in burn scar area, and significant improvements in self-esteem at 3 months post-treatment (P = 0.03). LIMITATIONS: Small sample size and lack of control group. CONCLUSIONS: Fractional resurfacing is a promising new treatment modality for burn scars. We should continue to identify novel approaches and management strategies for the spectrum of diverse burn scars so that we can better treat this patient population.

Fractional CO(2) laser-assisted drug delivery.

BACKGROUND AND OBJECTIVES: Ablative fractional resurfacing (AFR) creates vertical channels that might assist the delivery of topically applied drugs into skin. The purpose of this study was to evaluate drug delivery by CO(2) laser AFR using methyl 5-aminolevulinate (MAL), a porphyrin precursor, as a test drug. MATERIALS AND METHODS: Two Yorkshire swine were treated with single-hole CO(2) laser AFR and subsequent topical application of MAL (Metvix(R), Photocure ASA, Oslo, Norway), placebo cream and no drug. MAL-induced porphyrin fluorescence was measured by fluorescence microscopy at skin depths down to 1,800 microm. AFR was performed with a 10.6 microm wavelength prototype CO(2) laser, using stacked single pulses of 3 millisecond and 91.6 mJ per pulse. RESULTS: AFR created cone-shaped channels of approximately 300 microm diameter and 1,850 microm depth that were surrounded by a 70 microm thin layer of thermally coagulated dermis. There was no porphyrin fluorescence in placebo cream or untreated skin sites. AFR followed by MAL application enhanced drug delivery with significantly higher porphyrin fluorescence of hair follicles (P<0.0011) and dermis (P<0.0433) versus MAL alone at skin depths of 120, 500, 1,000, 1,500, and 1,800 microm. AFR before MAL application also enhanced skin surface (epidermal) porphyrin fluorescence. Radial diffusion of MAL from the laser-created channels into surrounding dermis was evidenced by uniform porphyrin fluorescence up to 1,500 microm from the holes (1,000, 1,800 microm depths). Skin massage after MAL application did not affect MAL-induced porphyrin fluorescence after AFR. CONCLUSIONS: Ablative fractional laser treatment facilitates delivery of topical MAL deeply into the skin. For the conditions of this study, laser channels approximately 3 mm apart followed by MAL application could produce porphyrins throughout essentially the entire skin. AFR appears to be a clinically practical means for enhancing uptake of MAL, a photodynamic therapy drug, and presumably many other topical skin medications.

Treatment of hypertrophic and resistant port wine stains with a 755 nm laser: a case series of 20 patients.

BACKGROUND AND OBJECTIVE: Port wine stains (PWS) are heterogeneous vascular malformations that can be treated with vascular-selective pulsed dye lasers (PDL). Hypertrophic PWS, especially in adults, are consistently less responsive to PDL. Furthermore, many PWS that respond well initially to PDL treatment may reach a response plateau, becoming unresponsive to further PDL treatments, a phenomenon termed "treatment resistance." Based on the theory of selective photothermolysis, vessels in such lesions may also be specifically targeted with a 755 nm laser that has selectivity for deoxyhemoglobin as well as oxyhemoglobin and increased depth of skin penetration. STUDY DESIGN/PATIENTS AND METHODS: Retrospective case review of 20 patients with either hypertrophic or PDL-resistant PWS treated with a 755 nm laser alone or in combination with other lasers, including PDL. RESULTS: Hypertrophic PWS showed significant lightening after treatment with a 755 nm laser in combination with PDL. Most PDL-resistant PWS showed moderate improvement after treatment with either a 755 nm laser alone or in combination with another laser, including PDL. Some lesions showed only mild improvement or did not respond. Serious side effects were infrequent. Most commonly encountered complications included pain, edema, bullae, crusting, and rare scarring. CONCLUSIONS: Alexandrite 755 nm laser can be useful for the treatment of hypertrophic and treatment-resistant PWS in adult and pediatric patients. Complications are infrequent and predictable. Careful attention to using a fluence at or near the threshold for clinical response with this deeply penetrating laser is essential to prevent serious sequelae.