Optimization of laser treatment safety in conjunction with cryogen spray cooling.
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Cryotherapy↗
Biomedical subjects
Kristen M Kelly
Publications and source records attributed to Kristen M Kelly.
Novel model for evaluation of epidermal preservation and dermal collagen remodeling following photorejuvenation of human skin.
BACKGROUND AND OBJECTIVES: In order to optimize photorejuvenation of human skin, a method must be developed to reliably compare the potential for epidermal preservation and dermal fibroblast stimulation of different laser devices and irradiation parameters. We describe a novel human skin tissue culture model developed for this purpose. MATERIALS AND METHODS: An artificial skin model, consisting of human keratinocytes in the epidermis and human fibroblasts and rat-tail collagen in the dermis, was cultured using the floating collagen gel (RAFT) method. Repetitive low-fluence Er:YAG laser irradiation was applied to test the applicability of our RAFT model for characterization of epidermal preservation and dermal fibroblast stimulation post-laser treatment. RESULTS: Histopathologic evaluation revealed a thin layer of epidermal keratinocyte preservation immediately after low fluence sub-ablative Er:YAG laser irradiation. One-week post-laser irradiation, the average increase in number of dermal fibroblasts as compared to control was statistically significant (P < 0.01). CONCLUSIONS: The RAFT model can be used to assess the potential for epidermal preservation and dermal fibroblast stimulation of different photorejuvenation devices and irradiation parameters and offers several advantages over traditional animal and human skin models.
Animals↗
Comparing the effectiveness of 585-nm vs 595-nm wavelength pulsed dye laser treatment of port wine stains in conjunction with cryogen spray cooling.
BACKGROUND AND OBJECTIVES: The objective of this study was to compare the efficacy and safety of cryogen spray cooled laser treatment (CSC-LT) at wavelengths of 585 nm vs. 595 nm for port wine stain (PWS) birthmarks in a large series of patients. STUDY DESIGN/MATERIALS AND METHODS: A retrospective review was conducted of 64 patients with PWS treated with the ScleroPLUS [Candela (Wayland, MA)] pulsed dye laser (lambda = 585 or 595 nm wavelength; spot size 7 mm, tau(p) = 1,500 microseconds) over a 3-year period. Subjects' ages ranged between 3 months and 64 years; there were 42 females and 22 males, all of whom were Asian. Number of treatments ranged from 1 to 6. Duration of treatment ranged from 6 months to 2 years 11 months, with a mean of 12 months. Patients (n = 32) received CSC-LT (585 nm) using radiant exposures of 7-10 J/cm(2). A second group of patients (n = 32) received CSC-LT (595 nm) using radiant exposures of 7-10 J/cm(2). The primary efficacy measurement was the quantitative assessment of blanching response scores for CSC-LT (585 nm) versus CSC-LT (595 nm). Patients were monitored for adverse effects. RESULTS: Based on chi-squared analysis, there were clinical, and statistically significant, differences in blanching response scores favoring PWS receiving CSC-LT (585 nm) as compared to CSC-LT (595 nm) (P <.001). Transient hyperpigmentation was noted in 43.7% (n = 14) and 37.5% (n = 12) of patients in the CSC-LT (585 nm) and CSC-LT (595 nm) groups, respectively. In both groups, transient hyperpigmentation resolved in all patients within 1 year. Permanent hypopigmentation or scarring was not observed in either group. CONCLUSIONS: CSC-LT (585 nm) resulted in superior blanching as compared to CSC-LT (595 nm). Further study is required to optimize wavelength selection on an individual patient basis during PWS therapy in order to improve treatment results.
Adolescent↗
Treatment of port-wine stain birthmarks using the 1.5-msec pulsed dye laser at high fluences in conjunction with cryogen spray cooling.
BACKGROUND: The majority of port-wine stain (PWS) patients treated with the pulsed dye laser (PDL) do not achieve complete blanching. Safe administration of higher fluences has been proposed as a means of improving treatment efficacy. OBJECTIVE: To determine the safety and efficacy of PWS treatment with the 1.5-msec PDL at high fluences in conjunction with cryogen spray cooling. METHODS: Twenty PWS patients were treated with the PDL in combination with cryogen spray cooling utilizing a 7 or 10 mm spot size and fluences ranging from 6 to 15 J/cm2. Before and after treatment photographs were compared on a blinded basis. RESULTS: No scarring or skin textural changes occurred. Blanching scores were as follows: 20% of patients achieved 75% or greater blanching after an average of 3.3 treatments, 30% achieved 50-74% blanching, 20% achieved 25-49% blanching, and 30% achieved less than 25% blanching. CONCLUSION: In conjunction with cryogen spray cooling, the PDL can be safely used at high fluences. At this time it is not clear that the use of higher fluences improves treatment efficacy; however, as other aspects of PWS laser treatment are optimized, safe administration of higher fluences is likely to be advantageous.
Adolescent↗
What is nonablative photorejuvenation of human skin?
Nonablative photorejuvenation has become an integral procedure in the emerging discipline of laser dermatologic surgery. The objective is to confine selectively, without any epidermal damage, thermal injury to the papillary, and upper reticular dermis leading to fibroblast activation and synthesis of new collagen and extracellular matrix material. The procedure results in minimal patient morbidity, no interference with lifestyle, and a low risk of complications, while providing a satisfying degree of rhytides reduction. Multiple devices have been studied and marketed for nonablative photorejuvenation of human skin. However, currently, nonablative photorejuvenation should not be considered an alternative to laser skin resurfacing. The skin surface is not removed or modified. What really occurs may be more accurately referred to as dermal "remodeling" or "toning" as a wound healing response is initiated and collagen regenerated. The narrow "therapeutic window" of laser-induced dermal heating and epidermal cooling must still be optimized so that effective treatments can be obtained routinely. Clinical verification of effective treatment parameters (irradiation wavelength, pulse structure, radiant exposure, cooling time) will be obtained through further human studies. Most importantly, understanding the relationship between the degree of dermal thermal injury and synthesis of new collagen and extracellular matrix material will be fundamental to predicting the clinical efficacy and limitations of nonablative photorejuvenation.
Humans↗
Description and analysis of treatments for port-wine stain birthmarks.
Port-wine stain (PWS) birthmarks are congenital, low-flow vascular malformations of the skin. Lasers are the modality of choice for the treatment of PWS birthmarks, and for most patients the pulsed-dye laser in conjunction with epidermal cooling offers the greatest efficacy and safety. Other light devices, including the 532-nm frequency-doubled Nd:YAG laser, intense pulsed light, 1064-nm Nd:YAG laser, and combined 1064/532-nm system, may be useful during a treatment course for resistant PWS. Laser treatment results in blanching of most lesions, although complete resolution may not occur and some resistant PWS birthmarks respond minimally, if at all. Factors limiting laser treatment include variable vascular geometry, inadequate damage of some vessels, and lesional posttreatment recurrence as a result of neovascularization. Alternative or adjunct treatment options that address these limitations should be explored, including noninvasive real-time imaging to optimize the selection of treatment settings, photodynamic therapy, and perioperative use of antiangiogenic compounds.
Adolescent↗