CC BY
15B-O-7
Laser-induced hydrodynamic effects in urological operation
V. Minaev1, N. Minaev2, V. Yusupov2, A. Dymov3, N. Sorokin3, V. Lekarev3, A. Vinarov3, L. Rapoport3
1NTO "IRE-Polus", medical applications department, Fryazino, Russian Federation 2Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, Institute of Photon Technologies, Moscow, Troitsk, Russian Federation 3I.M.Sechenov First Moscow State Medical University, Institute of Urology and Reproductive Health, Moscow, Russian Federation
When laser light with the wavelength of 1.94 |im is used in operations, performed in environment of physiological solution, three types of action on soft tissue are possible.
Contact mode: combination of laser light and heated in place of contact fiber end actions. This mode is followed by the bright shining in contact point, carbonization of biotissue and possible formation of viable fragments of pathological tissue (Fig.1 a).
At remote action the superintensive liquid boiling of near the output end of the fiber leading to formation of a steam-gas macrobubble which do not absorb light - "Mozes effect". If biotissue is in this bubble, then laser light act on it. In this case the area of action is well visualized and carbonization decreases (Fig.1 b).
At the power of laser light near 100 W the two-phase stream consisting of steam-gas microbubbles and heated water is formed at macrobubble distal end. Speed of this stream can exceed 1 m/s and it can cut soft biotissue (the mode of hydrodynamic section). In this mode the area of action is well controlled, there is no carbonization and the probability of emergence of viable fragments (Fig.1 c) is small.
Two last modes with the maximum pulse power of 120 W are effectively used for operations of prostatic hyperplasia enukleation and resections bladder wall with tumour.
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Fig.1. Modes: a - contact (CW, 60 W), b - "Mozes effect", c- hydrodynamic section. 1 - the end of the fiber, 2 - the place of contact, 3 - steam-gas macrobubble, 4 - two-phase stream.
