[Endoluminal diode laser vein damage: preclinic study for vein insufficiency]

The ex-vivo phase of this research aims to define fibre laser activity ranges with the intent of using a safety protocol on the operating table to ensure maximum results in occluding the vein lumen with minimum necessary energy parameters.

The study was performed on 20 human saphenous veins removed during phlebological surgery. A 1 mm diameter optical fibre was inserted in the vein to the proximal extremity where administration of laser energy began along the vein axis. The veins were subdivided into three groups based on the parameters used: Group 1: treated with 20 Watt power; Group 2, treated with 15 Watt power; Group 3, treated with 10 Watt power. On conclusion of the procedure the veins were immersed in formalin and sent for histological examination.

The greatest endothelial damage was observed in the group of veins treated with fluence above 300 J/cm(2), in which carbonisation of the endothelium was observed; in those treated with lower fluence (200-100 J/cm(2)) damage consisted in coagulation necrosis and interstitial oedema; at fluence of 100 J/cm(2) endothelial damage was less uniform.

Experimental evidence would appear to support the hypothesis that the optimal protocol is below 300 J/cm(2) fluence with 15 Watt power and pulse train 100-300 ms.