Mode selection of laser radiation with a wavelength of 980 nm for dissection of upper airway scars. Experimental study

Abstract

The aim of our work was the experimental development of the optimal laser radiation regime (laser wavelength 980 nm) for dissecting scars of the upper respiratory tract in terms of lateral thermal damage to surrounding tissues. Thermal damage is of fundamental importance when exposed to scar tissue, since it leads to inflammation in the dissection zone, which increases the risk of restenosis. The study was conducted on the basis of the Chair of Otorhinolaryngology with a clinic of Pavlov First Saint Petersburg State Medical University. A pork tendon was chosen as a model of biological tissue due to the similar optical and mechanical properties of scar tissue. The incision was made in the continuous contact mode at a power of 7 W and in the contact pulse mode at a power of 15 W (pulse – 20 ms, pause – 60 ms). The impact on the tissue in these modes was carried out in two directions: from the proximal edge of the tendon to the distal and vice versa. The measurement of the width of the ablation and coagulation zones was carried out under microscopic conditions using an eyepiece micrometer with an increase of ×40. The average width of the zone of lateral tissue damage when exposed in the contact pulse mode in the distal direction is 355±19 nm, which is comparable with the results of a CO2-laser in the superpulse mode.