Introduction & Objectives: Extracorporeal shock wave lithotripsy (ESWL) is the most commonly utilized method for treatment of renal and proximal ureteral stones. We aimed to observe which parameters are efficacious for ESWL success.
Materials & Methods: Between January 2017 and December 2018, 253 patients who underwent ESWL analyzed retrospectively from our prospectively obtained ESWL database. 44 patients underwent ESWL due to ureteral stones and 209 patients due to kidney stones. Siemens Lithostar Modularis Lithotripter were used for treatment. After treatment, kidney-ureter-bladder radiography, ultrasonography or computer tomography (for radiolucent stones) control was performed 21 to 30 days after an ESWL session and success was defined as stone disappearance or <4 mm residue fragments. After the first 3 sessions the patients with no stone passage and/or no decrease in stone size were defined as failure and referred to other treatment alternatives. Stone type, stone sizes, hounsfield unit density, stone-skin distance and location of stones, gender and ages of patients, also power and number of shock waves and total sessions were analyzed.
Results: The overall treatment success rate was 71.1% for all stones, 70.3% for renal stones and 75% for ureteral stones. Stone size, number of shock waves and Hounsfield unit density were efficacious parameters to predict success for renal stones. Age and stone size were predictors of success for ureteral stones in univariate analyses. In multivariate analyses just stone sizes were the only parameter as predictor of success for both renal and ureteral stones (p=0.002 and p=0.005 respectively) (Table-3). Success rate can be predicted for ureteral stones with sensitivity 81.8% and specificity 78% when 11.5 mm size defined as cut-off point (Figure-1).