Lasers in surgery and medicine
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Randomized Controlled Trial
Fractional nonablative 1540 nm laser resurfacing for thermal burn scars: a randomized controlled trial.
Burn scars cause permanent and disfiguring problems for many patients and limited treatments are available. Nonablative fractional lasers induce a wound healing response, which may lead to remodeling of burn scar texture. This randomized trial evaluates efficacy and adverse effects of 1540 nm fractional laser versus untreated control for burn scars. ⋯ Nonablative 1540 nm fractional laser improves burn scar texture, which raises a new potential for future burn scar treatment.
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Scars are usually classified into atrophic scars, hypertrophic scars and keloids. This author would classify atrophic scars as a subclass of non-hypertrophic scars. In other words, non-hypertrophic scars encompass atrophic (depressed) scars and flat scars that are literally flat or protrude minimally above the level of adjacent normal skin, because the same treatment protocol can be used for each. It is speculated that ablative lasers can be used to sculpt the contour of scars or to remove a controlled amount of scar tissue, while at the same time, activating a regenerative cascade. On the other hand, fractional and non-ablative lasers stimulate and/or keep a proliferative phase on, together with other unique beneficial effects of each device. ⋯ This study shows the possibility that, with appropriate combinations of different lasers, we can expect complete or near-complete resolution of many types of scars. Further research and data accumulation will help to establish better protocols for each class of scars.
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Comparative Study
Effects of laser irradiation on collagen organization in chemically induced degenerative annulus fibrosus of lumbar intervertebral disc.
The number of in vitro experimental studies was carried out with the use of intact tissues to establish a mechanism of laser-tissue interaction. However, in the process of degeneration, both biochemical composition and behavior of the disc were altered drastically. The objective of this study was to evaluate the role of the main matrix components in laser modification of annulus fibrosus (AF) under IR laser irradiation. ⋯ CP-OCT and DSC techniques allow us to record the alteration of collagen network organization as a result of chemical modification. There were detected significant and specific effects of the biochemical composition and material properties on the response of AF collagen network on laser irradiation. The results go in accordance with our hypothesis that the primary effect of laser influence on collagen network under tension is the mechanical damage of collagen fiber.
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Qualitative and quantitative gross histopathologic studies of skin damage were performed at 48 hours after irradiation with a 2.0 microm thulium CW laser to determine the mechanisms of laser effects in the skin under various exposure conditions. ⋯ A sequence of damage endpoints was defined in the skin as power increased. By choosing rate process coefficients to match specific mechanisms of lethal thermal damage, the optical-thermal-damage model is capable of predicting various types of thermal injury in the skin, such as epidermal necrosis, vascular thrombosis, and dermal collagen coagulation.
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The clinical usefulness of 5-ALA guided detection of tumor tissue has been demonstrated for a number of malignancies. However, current techniques of intraoperative detection of protoporphyrin IX fluorescence in situ do not offer subcellular resolution. Therefore, discrimination of non-specific 5-ALA induced fluorescence remains difficult. ⋯ Multiphoton microscopy of 5-ALA induced PpIX fluorescence in brain tumor tissue conceptually provides a high resolution diagnostic tool, which in addition to structural information may also provide photochemical/functional information.