Advances in Laser Lithotripsy and Stone Management
The synergy between ureteroscopy and laser technology has redefined the management of urolithiasis.
Both semi-rigid and flexible scopes utilize the Holmium:YAG laser, but the technique of fragmentation differs by scope type. In semi-rigid ureteroscopy, the stability of the instrument allows for "fragmentation and extraction," where the stone is broken into several large pieces and manually removed using a nitinol basket. This ensures immediate stone-free status but can be time-consuming. Because semi-rigid scopes have larger working channels, they can accommodate thicker laser fibers that deliver higher energy pulses without the risk of fiber breakage during bending.
Flexible ureteroscopy has popularized the "dusting" technique, particularly with the advent of high-frequency Thulium Fiber Lasers. In this approach, the laser is set to high frequency and low energy, pulverizing the stone into fine, silt-like dust. This dust is small enough to pass spontaneously with the patient's urine, reducing the need for tedious basket extraction and minimizing the risk of "Steinstrasse" (a column of stone fragments blocking the ureter). Furthermore, the extreme flexibility of modern laser fibers allows the flexible scope to maintain its full range of deflection even when the laser is active, ensuring that stones in difficult-to-reach lower pole calyces can be treated effectively without repositioning.