Introduction of 1.9 mm Trilogy lithotripter in miniature percutaneous nephrolithotomy: Description of technique and case outcomes.

Introduction: We aimed to evaluate the novel use of a 1.9 mm Trilogy lithotripter probe with varying locations and composition of renal stones.

Methods: We prospectively enrolled patients to undergo mini percutaneous nephrolithotomy (mPCNL) procedures using the 1.9 mm (instead of the standard 1.5 mm) Trilogy probe from August 2021 to April 2022. Several adjunctive irrigation measures compensated for reduced flow with the larger probe. Primary outcome was treatment efficiency. Patient demographics, preoperative demographics, and comorbidities, as well as real-time surgical data were extracted. Statistical analysis was performed using Kruskal-Wallis tests to compare stone type and location.

Results: A total of 110 patients were included in this study. The median total treatment time was 6.8 minutes, median lithotripsy time was 3.3 minutes, median stone treatment efficiency was 0.34 mm/min, and treatment efficacy was 50.4 (lithotripter time/treatment time). Overall median lithotripter efficiency was 104.6 mm³/min. Treatment efficiency was similar among stone composition (p=0.245) and location (p=0.263). Lithotripter 3D and 1D efficiency was also similar among stone composition (p=0.637 and p=0.766, respectively). Lithotripter 1D efficiency was nearly twice as fast in the lower pole compared to other stone locations (p=0.010). Overall broken probe rate for this procedure was 12%, mostly at the beginning, suggesting a learning curve. Five patients had minor complications, including one patient that required admission to the hospital for postoperative pain management.

Conclusions: The 1.9 mm Trilogy lithotripter can be effective in mPCNL procedures with the use of easily implementable adjunctive irrigation techniques, decreasing the gap between lithotripsy time and total treatment time.