Presented by: Arsha Reddy Venkat MD
New York Medical College

Introduction

Mini Percutaneous Nephrolithotomy (mPCNL) is widely used for complex stone disease but is limited by the size of lithotripter that can be used. We aim to evaluate the use of a larger 1.9mm Trilogy probe with varying locations and composition of renal stones.

Materials

We prospectively enrolled patients to undergo mPCNL procedures using the 1.9mm Trilogy probe technique from Aug 21- Apr 22. Adjunctive irrigation measures including retrograde irrigation were used to accommodate the larger probe. Patient preoperative demographics, and real-time surgical data were extracted. Stone volume was calculated with 3D Slicer, when DICOM images were available, or manually using an ellipsoid formula. Treatment time was from start of lithotripsy to total elimination of relevant stone from kidney. Lithotripsy time was total lithotripter-on time. Stone treatment efficiency was size of stone/total treatment time and treatment efficacy as lithotripter time/treatment time. Lithotripter efficiency was diameter (or volume in 3D)/lithotripter time in min. Statistical analysis was with a Kruskal-Wallis Test to compare both stone type and location.

Results

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110 patients were treated with 109 endoscopically stone-free after treatment. Median total treatment time was 6.8 min, median lithotripsy time was 3.3 min, median stone treatment efficacy was 0.34 mm/min, and treatment efficacy was 50.4. 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 0.766). Lithotripter 1D efficiency was nearly twice as fast in the lower pole compared to other stone locations (p=0.010). 5 patients had minor complications, including one patient that required admission to the hospital for postoperative pain management. Broken probe rate was 12%, mostly at the beginning, suggesting a learning curve.

Conclusion

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

Funding

EMS supplied the probes used in the study and provided administrative support. Julio Davalos is a Consultant for BSC, Storz, and EMS

Lead Authors

Arsha Venkat,
New York Medical College

Rebecca Kindler,
New York Medical College

Co-Authors

Natalia Arias Villela, MD
University of Maryland School of Medicine

Andy Martinez, MD
Chesapeake Urology Associates

William Meeks, MD
American Urological Association

Emily Galen, MD
American Urological Association

Joel Abbott, MD
Pacific West Urology

Meagan Dunne, MD
Chesapeake Urology Associates

Julio Davalos, MD
Chesapeake Urology Associates