Condrodermatitis nodular del antihélix por teléfono móvil / Cell Phone–Induced Chondrodermatitis Nodularis Antihelicis

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Preliminary investigations on therapy thresholds for laser dosimetry, cryogen spray cooling duration, and treatment cycles for laser cartilage reshaping in the New Zealand white rabbit auricle.

Previous studies have demonstrated the feasibility of laser irradiation (λ = 1.45 µm) in tandem with cryogen spray cooling (CSC) to reshape rabbit auricular cartilage using a total energy density of 14 J/cm(2). The aim of this study was to further explore and identify the dosimetry parameter space for laser output energy, CSC duration, and treatment cycles required to achieve shape change while limiting skin and cartilage injury. Ten New Zealand white rabbits were treated with the 1.45 µm diode laser combined with cryogen spray cooling (Candela Smoothbeam™, Candela Co., Wayland, MA, USA). The ear's central portion was bent around a cylindrical jig and irradiated in consecutive spots of 6 mm diameter (13 or 14 J/cm(2) per spot) along three rows encompassing the bend. CSC was delivered during irradiation in cycles consisting of 25-35 ms. At thin and thick portions of the ear, 4-7 and 6-10 treatment cycles were delivered, respectively. After surgery, ears were examined and splinted for 6 weeks. Treatment parameters resulting in acceptable (grades 1 and 2) and unacceptable (grade 3) skin injuries for thick and thin regions were identified, and shape change was observed. Confocal and histological analysis of cartilage tissue revealed several outcomes correlating to laser dosimetry, CSC duration, and treatment cycles. These outcomes included expansion of cartilage layers (thickening), partial cartilage injuries, and full-thickness cartilage injuries. We determined therapy thresholds for laser output energy, cryogen spray cooling duration, and treatment cycles in the rabbit auricular model. These parameters are a starting point for future clinical procedures aimed at correcting external ear deformities.

The histological and clinical effects of 630 nanometer and 860 nanometer low-level laser on rabbits' ear punch holes.

Low-level laser therapy (LLLT) studies on the musculoskeletal and cartilage tissues of rabbits have reported conflicting results. We aimed to investigate the effects of 630 nm and 860 nm low-level laser on injured rabbit cartilage. After punching 5 mm holes in both ears of ten rabbits, we grouped the rabbits randomly. The punched holes of the laser-treated group were irradiated with 630 nm and 860 nm diode laser on days 3-5 and then every other day until day 20. In both laser and control groups, the hole diameters were measured weekly. Histological evaluation was carried out on day 30. The inter-group difference in hole diameters was not significant. Mann-Whitney U tests showed significant inter-group differences in histological variables related to chondrocyte production and organization, growth rate, granulation tissue and pseudocarcinomatosis. LLLT improved cartilage formation and reduced inflammation and formation of granulation tissue. More accurate results on its healing effects warrant studies with larger sample sizes.

In vitro enzymatic treatment and carbon dioxide laser beam irradiation of morphologic cartilage specimens.

OBJECTIVES: To determine the role of the main cartilage components in the internal system of interlocked stresses and to clarify the effect of laser beam irradiation on cartilage. DESIGN: Control and experimental series. SUBJECTS: Rabbit ear cartilage. INTERVENTION: Rabbit ear cartilage strips incubated in collagenase and hyaluronidase enzyme solutions for specific periods were examined, and the observed changes in shape, strength, and elasticity were recorded, as well as the effect of carbon dioxide laser irradiation. Laser-pretreated cartilage strips were also incubated in the enzyme solutions to determine whether the laser-provoked changes were susceptible to enzymatic action. All cartilage pieces were examined by light and electron microscopy. RESULTS: Collagenase-treated cartilage strips gradually lost their interlocked stresses, while hyaluronidase-treated strips mostly maintained their shape and their physical characteristics. Hyaluronidase-incubated cartilage strips altered their shape when they were laser treated. Collagenase-treated cartilages did not modify their shape when they were laser treated. Laser-pretreated cartilage pieces lost their new form in collagenase solutions but kept their laser-evoked shape when put in hyaluronidase solutions. CONCLUSION: The macroscopic observations combined with light and electron microscopy findings argue for the distinct role of the collagen network in morphologic cartilage shape and tensile strength preservation and provide a probable mechanism of cartilage transformation owing to carbon dioxide laser irradiation.

Raman microspectrometry of laser-reshaped rabbit auricular cartilage: preliminary study on laser-induced cartilage mineralization.

Laser-assisted cartilage reshaping (LACR) is a relatively novel technique designed to noninvasively and permanently restructure cartilaginous tissue. It is believed that heat-induced stress relaxation, in which a temperature-mediated disruption of H2O binding is associated with conformational alterations in the proteoglycan and collagen-rich matrix, constitutes the underlying mechanism of LACR. Several reports have suggested that laser-mediated cartilage mineralization may contribute to the permanent shape change of laser-reshaped cartilage. In an effort to validate these results in the context of Er:glass LACR, we performed a preliminary Raman microspectrometric study to characterize the crystal deposits in laser-irradiated chondrocytes and extracellular matrix. For the first time, we identified intracellular calcium sulfate deposits and extracellular calcium phosphate (apatite) crystals in laser-reshaped rabbit auricular cartilage. Calcium carbonate deposits are localized in both irradiated and nonirradiated samples, suggesting that this mineral plays no role in conformational retention. In our discussion, we elaborate on the possible molecular and cellular mechanisms responsible for intra- and extracellular crystallization, and propose a novel hypothesis on the formation of apatite, inasmuch as the biological function of this mineral (providing structure and rigidity in bones and dental enamel) may be extrapolated to the permanent shape change of laser-irradiated cartilage.

Effect of the carbon dioxide laser on viability of ear cartilage in a rabbit model.

The carbon dioxide (CO2) laser can be used for rapid, detailed sculpting of cartilage for creation of an ear framework for reconstruction of microtia. Clinical and animal studies of the effect of the CO2 laser have noted good healing with little evidence of a zone of tissue injury adjacent to the laser incisions. The current study has investigated the longer term effect of CO2 on chondrocyte viability in a rabbit ear model in which the laser has been used to incise autogenous cartilage segments for implantation into subcutaneous pockets. Over a 3-month period, the conformational integrity of the segments, when compared to segments incised with a scalpel, was no different. However, radioactive sulfur uptake studies to assess the viability of chondrocytes indicated a decrease in chondrocyte density in those specimens that have been subjected to laser incisions. Although other studies of acute cellular injury indicate that the CO2 laser may be beneficial for cartilage incision and sculpting, the current study indicates that resorption over longer periods of time might be encountered as a consequence of decreased chondrocyte viability in the vicinity of the laser incisions.