THE APPLICATION OF HOLMIUM LASER IN TREATMENT OF URINARY CALCULI
Medhat Ahmad Abdalla;
Abstract
Application of laser energy is finding an increasing role in a number of medical and surgical specialties. The keen interest in urologic laser surgery is a natural evolution considering the endoscopic expertise of urologists and the sophisticated instrumentation that allows endoscopic access to vi1tually the entire urinary tract. However, these factors have somewhat impeded the progress of laser urologic surgery, because effective alternative therapy exists in many of the areas in urology in which lasers are being used. Nevertheless, interest in laser surgery is increasing at an astounding rate in the armamentarium of the clinical
urologist. ( 461
A wide range of endoscopic lithotriptors has become available for fi•agmentation of urinary calculi. They can be divided broadly into three categories: direct contact mechanical lithotriptors, devices that work by means of a shock-wave effect and laser lithotriptors. (GO)
Several lasers are currently available for intracorporeal stone fragmentation. They differ significantly in wavelength, pulse duration, and pulse energy. However, initial laser lithotriptors (pulsed dye, Q switched YAG, 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 turn is a result of the short pulse duration of the released lithotrite energy.
The bigger and more symmetric the growth of the cavitation bubble, the stronger the acoustic emission produced when it collapses.
urologist. ( 461
A wide range of endoscopic lithotriptors has become available for fi•agmentation of urinary calculi. They can be divided broadly into three categories: direct contact mechanical lithotriptors, devices that work by means of a shock-wave effect and laser lithotriptors. (GO)
Several lasers are currently available for intracorporeal stone fragmentation. They differ significantly in wavelength, pulse duration, and pulse energy. However, initial laser lithotriptors (pulsed dye, Q switched YAG, 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 turn is a result of the short pulse duration of the released lithotrite energy.
The bigger and more symmetric the growth of the cavitation bubble, the stronger the acoustic emission produced when it collapses.
Other data
| Title | THE APPLICATION OF HOLMIUM LASER IN TREATMENT OF URINARY CALCULI | Other Titles | استخدامات الهولميوم ليزر فى علاج حصوات المسالك البولية | Authors | Medhat Ahmad Abdalla | Issue Date | 2001 |
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