|Authors||Bell JR, Penniston KL, Nakada SY|
|Publish Date||2017 Jul 20|
INTRODUCTION AND OBJECTIVE There is limited data regarding optimal laser and energy settings during stone fragmentation. We assessed effects on fragmentation using a variety of energy and frequency settings with two laser systems. METHODS Artificial stones were created using BegoStone (Streeper et al 2016). A clear PVC tube with an inner diameter of 13mm was closed at one end with a removable plug to create the in vitro ureteral and calyceal environments. The Lumenis Pulse 120H and the Cook Rhapsody H-30 holmium lasers were studied in the calyceal and ureteral models. A single urologist fragmented each stone to <2mm. The calyceal studies assessed the time to fragmentation (n=56); whereas the ureteral studies measured the retropulsion distance of each stone phantom after five minutes of laser treatment time using different pulse widths settings (n=15). RESULTS Complete treatment of the stone in the calyceal model with the 120H required 10.9min at ≥1J vs 26.9min at <1J (P<0.001). The H-39 showed treatment times of 11.2min at ≥1J vs 22.8min at <1J (P<0.001). There was no significant difference in treatment time when comparing the two lasers using settings of 0.8Jx8Hz and 1.5Jx10Hz in the calyceal model (25.5 vs 24.8min, P=0.861; and 13.2 vs 9.5min, P=0.061; respectively). Ureteral studies with the 120H showed retropulsion distances of 13.9cm using long pulse, 25.2cm using medium pulse, and 56.6cm using short pulse. Retropulsion distances using the H-30 laser were 7cm using long pulse and 14.5cm using short pulse which differed from the 120H (P<0.001). CONCLUSIONS Fragmenting stones to <2mm was faster with both lasers when energy settings of ≥1J were used. Treatment times using the 120H and the H-30 lasers were equivalent. Retropulsion distances were less with both lasers when longer pulse widths were used. The H-30 resulted in less stone retropulsion compared to the 120H.