Presented by: Luis Rico MD
Hospital Alemán de Buenos Aires, Argentina

Introduction

The new pulse modality Vapor-Tunnel™ (VT) consists of a very long pulse that uses the minimum peak power, causing the energy to pass through a previously created vapor channel or tunnel. There are multiple studies that have shown excellent dusting lithotripsy efficacy. However, there are no in-vivo studies that have compared the VT lithotripsy efficacy according the to the stone density.

Materials

A retrospective comparative study of 152 patients who underwent retrograde intrarenal surgery using VT Ho:YAG laser was performed. We included non-complex kidney stones (Guy Stone I) and excluded multiple kidney stones. We divided the patients according the stone density (Group 1: <1000UH vs Group 2: >1000UH). In all procedures, 1J/10Hz (10W) with VT pulse modality was utilized. Stone size, body mass index (BMI), laser emission time, and total operative time were recorded. We also assessed the lithotripsy efficacy (Joules/mm3). The stone-free rate was defined as the absence of stone fragments in a non-contrast abdominal computed tomography four weeks after the procedure

Results

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93 patients were included in Group 1 and 59 in Group 2. There was no significant difference in age, gender and stone location. BMI was significant higher in Group 1 (27.3 vs 25.2) and the median stone volume was higher in Group 2 (846 vs 672mm3). Total energy used (11.9kJ vs. 24kJ), the laser emission time (19min vs. 30min), and the total operative time (60min vs. 85min), were significantly lower in the Group 1. Stone-free rate (SFR) was significantly higher in Group 1 (96.7% vs 57.6%, p<0.001) with a total SFR of 81.6%. In Group 1 all the patients were discharged on the same-day (p<0.001) and when we evaluated the efficacy of laser lithotripsy, a significantly lower difference was obtained (median 18.6 Joules/mm3 vs. median 18.6 Joules/mm3).

Conclusion

In soft stones (<1000UH) the VT pulse modality was associated with decreased laser time and operative time. Additionally, it increased lithotripsy efficacy and the SFR compared to hard stones (>1000UH) with the same laser settings and pulse modality.

Funding

No funding

Lead Authors

Pablo Contreras,
Hospital Alemán de Buenos Aires, Argentina

Sofia Butori,
Hospital Alemán de Buenos Aires, Argentina

Leandro Blas,
Hospital Alemán de Buenos Aires, Argentina

Emanuel Martinez Pagano,
Hospital Alemán de Buenos Aires, Argentina

Carlos Ameri,
Hospital Alemán de Buenos Aires, Argentina