Endovenous laser treatment: a morphological study in an animal model

Abstract

The ELT of veins produces an unevenly distributed damage. The cell necrosis is far more extensive than expected. Uneven vein wall destruction can lead to recanalization. Using a 1500 nm laser correlates with less penetrating ulcerations and more circumferential damage.

Thrombosis versus thermal coagulum formation as a result of endovenous laser treatment: Biochemistry versus photophysics

“…31 It is expected that, immediately after the fiber has been retracted from the vein, blood flow is restored until a state of thrombostasis has been reached due to the extensive intimal damage and proportional extent of coagulation (non-thermal clotting), probably within minutes. The restoration of blood flow immediately following ELT has been confirmed by reports on the occurrence of post-treatment hematomas 32,38 caused by laser-induced perforation of the vein wall and extravasation of blood into surrounding tissue 9,32,33 (histologically shown in for example Figure 6 (perforation) and Figure 4 (extravasation) in Vuylsteke et al 36 ). In light of this background information, the work by Hennings et al 19 should be reanalyzed.…”

“…8 The types of thermal affliction to endothelial cells that are known to trigger thrombosis, including hyperthermic activation, 26,27 necrotic cell death, 13 and denudation (i.e., exposure of the internal elastic lamina, a highly thrombogenic surface), 7 span a broad temperature range (41-100 C, Figure 1) that is easily achieved during ELT. 4,9,34 The biochemical response to this particular endovascular damage profile, which mainly entails secondary hemostasis (activation of coagulation), 31 is therefore believed to be responsible for the initial thrombotic closure of the vein, as shown in exemplary micrographs of histological preparations of veins that had been subjected to ELT (for example, Figure 3A and C in Proebstle et al, 35 Figures 2, 7, 9, and 11 in Vuylsteke et al, 36 and Figures 5 and 7 in Vuylsteke et al 37 ). Coagulation-mediated thrombus formation requires blood flow in the treated vein for the supply of coagulation factors that are responsible for producing fibrin, the main component of venous thrombi.…”

Clinical Assessment of Tissue Healing of Extracted Sockets Irradiated with 940 Nm Diode Laser

“…The penetration depth of the radiation was (0.692) mm, which was measured from the absorbance value (1.999) that equal to (the ratio of incident intensity to the absorbed intensity) and the Absorbance A is equal to -log the Transmittance T which in turn is equal to the (ratio between incident to transmitted intensities) and from an equation: T= 10 -A (Beer-Lambert Law); A= -log T; optical depth= ln 10 A (17,18) . From the previous measurement, that's mean (0.692mm) of blood was coagulated because clotting is due to apsorption (Vuylsteke, 2009;Mirdan, 2012), the underlying areas of blood filled the socket beneath the absorption depth, there is layers of blood exposed to scattered laser light, which cause biostimulation effect that cause the extraction wound healing acceleration, this finding was agreed with (15,19) who used 980 nm diode laser in 0.86 W for the purpose of extraction wound site coagulation of a rabbit tooth socket. Vuylsteke and Mirdan stated that: 'Due to fluctuations in the refractive index of these media (blood during the coagulation process), the propagation of light into the tissue is modified and the scattering affects where the absorption will occur.…”

“…Heating decreases with tissue depth, as absorption and scattering attenuate the incident beam. At 940 nm-980 nm wavelengths, scattering coefficient is 0.6 -0.64 mm -1 and absorption coefficient 0.25-0.28mm -1 in blood gives out an optical extinction coefficient of 0.82-0.86 mm -1 (19) . Those numbers prove that clotting was achieved due to absorption.…”

Comparison of Bare-Tip and Radial Fiber in Endovenous Laser Ablation with 1470 nm Diode Laser

“…The presence of blood is essential for ablation of veins with an HSLW laser, but a WSLW laser does not necessarily require blood, and it causes strong and reliable ablation when blood is absent. 14) At near-infrared wavelengths, peaks of water absorption are present at about 980, 1470, and 2000 nm. Absorption by water becomes stronger as the wavelength becomes longer.…”