Prospective Randomized Study of Fixed Laser Setting Verses Variable Laser Settings for a Better Stone Free Rate

OBJECTIVE: To assess the outcome of variable laser settings verses fixed setting on the stone free rate and complications. MATERIAL AND METHOD: We conducted a prospective, single-blind randomized controlled study. Solitary renal non lower pole stones 10 to 20 cm were included. A total of 113 Patients were randomly divided in to two groups. In group A, fixed laser setting was used at 1.0J energy and 12Hz frequency during the entire procedure. In Group B, variable laser settings were used; initial fine fragmentation was performed @ 1.0J X 12Hz. Once the residual stone reduced enough to wobble, the energy was reduced to 0.8 J and 8Hz. Settings were further reduced to 0.5J and 5Hz as required to complete the fragmentation process with minimal migration. RESULT: Group A had 58 patients and Group B 55 patients for analysis of perioperative variables. Stone free rate (<2mm) is in favor of systematic stone dusting with variable frequency (95.8% vs 83.6%, p=0.05). Post-operative fever and pain were not statistically significant between the groups (fever 10.3% vs 9.1%, p=1.00) (pain mean VAS 1/10 in group A vs 2/10 in group B). CONCLUSION: The solitary hard stones of 10 to 20 mm can be treated with more than 95% SFR using variable laser settings producing fine dust, without increase in significant postoperative complications or hospital stay.