MANAGEMENT OF URETERIC STONES USING HOLMIUM LASER

Abstract

A wide range of endoscopic lithotriptors has become available for fragmentation of urinary calculi. They can be divided broadly into three categories: direct contact mechanical lithotriptors, devices that work b)'. means of a shock-wave effect and laser lithotriptors. ('.SJ

Sev era! lasers are currentlv available for intracorporeal stone fragmentation. They significantly differ in wavelength, pulse duration, and pulse energy. However, initial laser lithotriptors (pulsed dye, Q• switched Y AG, and alexandrite) have all been found to fragment stones through generation of a shock wave.

These short pulsed lasers and electro hydraulic probes induce the rapid formation of a spherical plasma cavitations bubble that expands symmetrically to a maximum size and then collapses violently.

Bubble collapse leads to the generation of a strong shock wave: it is the impingement of this shock wave upon the targeted stone ( or nearby tissue or endoscopic equipment ) that comprises the primary mechanism of fragmentation. Importantly, the generation of a strong shock wave depends on the shape and geometry of the cavitation bubble, which in tum is a result of the short pulse duration of the released lithotrite energy.

The Ho: YAG laser produces light of 2, 100 nm in a pulsed fashion. This light has a wavelength that lies in the infrared part of the electromagnetic spectrum. This wavelength is strongly absorbed by