Stone density and skin-to-stone distance in noncontrast computed tomography as prognostic indicators for the success of extracorporeal shock wave lithotripsy in ureteral stone disease

ElMoazen, Mohamed; ElShafei, Ahmed M.; Abdallah, Hany M.; Elghobashy, Samir Elsayed; Badawy, Mohamed Hussein; Emam, Ahmed; Gamal, Mohamed A.; Gad, Hany H.; Tawfeek, Ahmed M.

doi:10.4103/ejs.ejs_285_22

Stone density and skin-to-stone distance in noncontrast computed tomography as prognostic indicators for the success of extracorporeal shock wave lithotripsy in ureteral stone disease

Authors

Abstract

Background
Urinary stones are becoming more common, which is a major health issue. Ureteral stones that originate in the kidney and then descend the ureter are a frequent cause of renal colic. Extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy are the two main procedures used to treat symptomatic ureteral calculi.
Aim
The aim of the present study was to assess the prognostic significance of skin-to-stone distance (SSD) and mean stone attenuation value in patients who may be candidates for ESWL for ureteral stones.
Patients and methods
This retrospective cohort observational study evaluated the prognostic value of SSD, mean attenuation value, and BMI in 66 patients with upper ureteral calculi who underwent ESWL. After a maximum of two sessions, if no stone particles were discovered, we categorized patients as stone free. Age, sex, SSD, maximum stone length, and stone Hounsfield units were examined in univariate and multivariate regression analyses.
Results
We found that factors including obesity (BMI >30.41), high stone density (Hounsfield units >935), and SSD more than 10 cm limited the effectiveness of therapy. On the contrary, higher shock levels (>2500 shocks each session) and shock intensities (>17 kV) were reliable indicators of treatment success.
Conclusion
We proposed a thorough analysis of the parameters prior to therapy to choose the best treatment option for each patient. It was found that a patient and stone feature before ESWL evaluation can predict the outcome of ureteric stone therapy. It was found that using these criteria can improve patient selection for ESWL and consequently ESWL effectiveness.

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