Factors Determining the Number of Sessions in Successful Extracorporeal Shock Wave Lithotripsy Patients

Abstract

Background and aim - The aim of this study is to investigate whether certain clinical nomograms influencing the success of extracorporeal shock wave lithotripsy (ESWL) also play a role in determining the number of treatment sessions required in patients who achieved stone-free status following ESWL. Methods - The data of 354 patients with successful ESWL outcomes were analyzed. Patients were evaluated 4-6 weeks post-ESWL using X-ray, ultrasound, or computed tomography. The presence of residual stones larger than 4 mm was considered a treatment failure. Data recorded included age, gender, laterality of stone localization (right/left), stone location (renal pelvis, mid calyx, upper calyx, proximal ureter, mid ureter, distal ureter), stone size (maximum longitudinal dimension), body mass index (BMI), and stone Hounsfield unit (HU) values. Patients were categorized into two groups: single-session and multiple-session treatment. Results - In the univariate model, factors such as age, BMI, distal ureter, renal pelvis, mid-calyx stone localization, stone size, and stone HU value showed a significant (p < 0.05) effect in distinguishing between single-session and multiple-session groups. Stone size and HU values were significantly higher (p < 0.05) in the multiple-session group compared to the single-session group. In the multivariate model, age, stone size, and HU value emerged as significant independent factors (p < 0.05) in differentiating between single-session and multiple-session treatments. Conclusion - Several factors influencing the success of ESWL also affect the number of sessions required. BMI, age, stone size, stone HU value, and certain stone locations are key determinants of the number of ESWL sessions.