Holmium:YAG laser ureterolithotripsy.

Objective: To report on the experience obtained in the treatment of a series of 150 cases of ureteral stone disease by means of the holmium:yttrium-aluminum-garnet (Ho:YAG) laser.

Methods: One hundred and fifty consecutive cases treated by means of Ho:YAG laser ureterolithotripsy have been reviewed in order to assess the results. In 81 cases the stones were located in the lower third, in 47 in the medium third, and in 22 cases in the upper third of the ureter. The laser was set at a power of 8-10 W and at a frequency of between 6 and 10 Hz. Thin ureteroscopes were selected, such as the 7-Fr Gautier or the new ultrathin 4.8-Fr Wolf instrument. In some cases other ureteroscopes were chosen.

Results: Lasertripsy was effective in every kind of stone, allowing fragmentation into portions measuring at most 4 mm (largest diameter) or disintegration. The clearance rate of the stones was 92.6% during the 30-day follow-up period. Calcium dihydrate stones were of course more easily broken than monohydrate ones. No damage to the ureter was observed following the vaporization which is produced by this kind of laser, since particular attention was paid to avoid any contact between the laser beam and the ureteral mucosa. In some instances ureteroscopic maneuvering provoked some slight lacerations. In a few cases accidental contact of the laser beam with the ureteral mucosa produced extremely small coagulations of no immediate or postoperative relevance.

Conclusions: The Ho:YAG laser constitutes an effective instrument for the fragmentation of any kind of ureteral stone; it allows the use of thin or ultrathin instruments and, if manipulated with care, does not damage the ureteral mucosa or the ureteral wall.