The histology of laser thermo-chondro-plasty

Helidonis, Emmanuel S.; Volitakis, Miltos; Naumidi, Irene; Velegrakis, George A.; Bizakis, John G.; Christodoulou, Panayiotis

doi:10.1016/0196-0709(94)90083-3

Cited by 30 publications

(13 citation statements)

References 9 publications

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“…Laser assisted reshaping of cartilage is a new surgical procedure designed to allow in-situ treatment of deformities with less morbidity than traditional procedures [1][2][3][4][5][6][7][8][9][10][11][12][13]. During laser irradiation, mechanically deformed cartilage undergoes a subtle change in material properties that permits tissue to be reshaped into new stable configurations [5,6,11,12,[14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…Cartilage softens and can be reshaped when heated using laser, RF, or contact heating sources. The objectives of this study were to: (1) measure temperature dependent flexural storage moduli and mechanical relaxation in cartilage, (2) determine the impact of tissue water content and orientation on these mechanical properties, and (3) use these measurements to estimate the activation energy associated with the mechanical relaxation process. Study Design/Materials and Methods: Porcine nasal septal cartilage specimens (30 Â 10 Â 2 mm) were deformed using a single cantilever arrangement in a dynamic thermomechanical analyzer.…”

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confidence: 99%

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Characterization of temperature dependent mechanical behavior of cartilage

et al. 2003

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The anisotropic mechanical behavior of cartilage was quantitatively analyzed in the transversely and longitudinally oriented specimens. Viscoelastic behavior appeared to be strongly dependent on the water content. Using empirically determined estimates of the transition zone temperature range accompanying stress relaxation, the activation energy for stress relaxation was calculated using time and temperature superposition theory and WLF equation. Further investigation of the molecular changes, which occur during laser irradiation, may assist in understanding the thermal and mechanical behavior of cartilage and how the reshaping process might to be optimized.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Characterization of temperature dependent mechanical behavior of cartilage

et al. 2003

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“…The histological analysis of cartilage reshaped by laser radiation with wavelengths of 10.6 m [2,17,18] or 1.44 nm [15,16] have shown considerable alterations in the cartilage matrix, whereas our results with the holmium laser have enabled us to define the 'gap' which allows laser shaping, but avoids damage to cartilage matrix [10]. If cartilage pieces of 1 mm in thickness are laser treated for 4 s at 2.2 J/cm 2 this is enough to allow stress relaxation to occur, but less than this is inadequate to cause a significant alteration in cartilage structure.…”

Section: Introductionmentioning

confidence: 99%

A Prospective Randomised Study of Laser Reshaping of Cartilage In Vivo

et al. 2001

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Laser reshaping using low laser energy levels was performed on the cartilage of ten porcine ears. The ears were examined up to 4 months after laser reshaping and the stability of the reshaping was assessed by photography and casts obtained from alginate impressions of the ears. The cartilage was also studied histologically in three animals at 3 weeks, 8 weeks, and 4 months using haematoxylin and eosin (H&E), periodic-acid-Schiff (PAS) and alcian blue stains as well as Mib-1 antibody stain to detect cells in cycle. These ears were compared with the other control or non-irradiated ear. All the treated ears initially demonstrated a controlled alteration in their shape. Four were exposed to a pulse energy of 2 J/cm2 at 20 Hz with a spot diameter of 1.1 mm for 7 s and retained their shape for up to 14 days. However, the three exposed to the same levels of energy for 9 s showed tissue necrosis whereas the three which were treated for less than 4 s returned to their original shape after 24 h. Histological examination revealed that there was a dramatic eccentric proliferation of perichondrium away from the centre of irradiation with a noticeable absence of any inflammation. In all laser-irradiated areas there was a loss of staining with PAS and a dramatic increase in staining with alcian blue within the cartilage matrix. Viable chondrocytes were absent from the irradiated cartilage. Staining with a Mib-1 antibody that detects cells in cycle showed positive staining in a small fraction of proliferated perichondrial cells where new cartilage had been produced.

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“…It has been suggested that shape change is caused by the disruption of the intermolecular forces within the cartilage, as well as by collagen denaturation. 36–38 Additional studies describe the role of stress relaxation and phase transformation between free and bound water during laser heating. 39,40 These investigations have demonstrated that the shape change process during laser heating occurs between 70°C and 80°C.…”

Section: Commentmentioning

confidence: 99%

Stabilization of Costal Cartilage Graft Warping Using Infrared Laser Irradiation in a Porcine Model

Foulad

Ghasri²,

Garg³

et al. 2010

Arch Facial Plast Surg

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Objective To develop a method to rapidly stabilize the shape change process in peripheral slices of costal cartilage by using infrared laser irradiation in a porcine model. Methods Forty peripheral porcine costal cartilage specimens (40×10×2 mm) were harvested. Thirty of these specimens were immediately irradiated with an Nd: YAG laser (λ=1.32 μm; spot size, 2-mm diameter) using 1 of 3 exposure treatments: 6W, 2 seconds, and 4 spots; 8 W, 3 seconds, and 4 spots; or 6 W, 2 seconds, and 8 spots. Ten control specimens were only immersed in 0.9% saline solution. Angle of curvature was measured from photographs taken at 0 minutes, immediately after irradiation, and at 30 minutes, 1 hour, 5 hours, and 24 hours. Infrared imaging was used to measure surface temperatures during irradiation. Cell viability after irradiation was determined using a live/dead assay in conjunction with fluorescent confocal microscopy. Results Compared with the untreated controls, the irradiated grafts underwent accelerated shape change within the first 30 minutes to reach a stable geometry. Thereafter, irradiated grafts underwent little or no shape change, whereas the control group exhibited significant change in curvature from 30 minutes to 24 hours (P<.001). The average peak irradiated spot temperatures ranged from 76°C to 82°C. Cell viability measurements at the laser spot sites demonstrated a hemispherically shaped region of dead cells with a depth of 0.8 to 1.2 mm and a surface diameter of 1.9 to 2.7 mm. Conclusions Laser irradiation of peripheral costal cartilage slices provides an effective method for rapidly stabilizing acute shape change by accelerating the warping process. The temperature elevations necessary to achieve this are spatially limited and well within the limits of tolerable tissue injury.

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The histology of laser thermo-chondro-plasty

Cited by 30 publications

References 9 publications

Characterization of temperature dependent mechanical behavior of cartilage

Characterization of temperature dependent mechanical behavior of cartilage

A Prospective Randomised Study of Laser Reshaping of Cartilage In Vivo

Stabilization of Costal Cartilage Graft Warping Using Infrared Laser Irradiation in a Porcine Model

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