The Impact of Hounsfield Unit-related Variables on Retrograde Intrarenal Surgery Outcomes in Isolated Lower Pole Kidney Stones

Abstract

Aim:The Hounsfield unit (HU) value can predict the stone-free status of retrograde intrarenal surgery (RIRS) for kidney stones. The purpose of this study was to investigate the effect of HU and HU-related variables on RIRS outcomes in isolated lower pole kidney stones.Methods:This single-center cross-sectional study was conducted between January 2017 and March 2023. One hundred thirty-three patients who underwent RIRS for lower pole kidney stones were evaluated. These were divided into stone-free (Group 1) and remnant (Group 2) groups, and the effects of the HU-related variables on RIRS outcomes were investigated.Results:One hundred-five (78.9%) patients in Group 1 and 28 (21.1%) in Group 2 were enrolled in the study. Significant differences were observed between the groups in terms of mean stone area (p=0.003), stone size (p<0.001), use of the ureteral access sheath (p=0.013), and operative time (p<0.001). The mean HU values were 795.09±287.55 in Group 1 and 927.64±302.6 in Group 2 (p=0.034). The mean HU density and HU intensity values were not significantly different between the groups (p=0.432 and p=0.207, respectively). The HU value was not identified as a dependent variable in the regression analysis.Conclusion:Hounsfield unit value, HU density, and HU intensity are not predictive of stone-free rates after RIRS in isolated lower pole kidney stones.

Keywords

• hounsfield unit
• kidney stone
• lower pole
• retrograde intrarenal surgery