Predictors of success of shock wave lithotripsy for ureteral stones based on computed tomography scan parameters

ABSTRACT

Background: For shock wave lithotripsy has proven to be an effective, safe and truly minimally invasive option for the treatment of nephrolithiasis. Various technical factors as well as patient selection can impact the success of the procedure. Objective: The aim of this study was to identify the parameters on NCCT that may predict the success of shock wave lithotripsy (SWL) in ureteral stones. Patients and Methods: 102 patients who underwent SWL for ureteral stones at sayed Galal University Hospital from January 2015 to August 2018 diagnosed by non-contrasted computed tomography were studied. The failure was defined as remnant stones ﻞ4 mm. We assessed age, sex, body mass index, stone size, location, skin-to-stone distance (SSD), presence of JJ and the presence of secondary signs (hydronephrosis, renal enlargement, perinephric fat stranding, and tissue rim sign). Results: 102 patients with success rate 61.8%, stone size, stone density were significantly associated with outcome of SWL. While SSD, JJ and secondary signs (hydronephrosis, perinephric fat stranding and tissue rim sign) were insignificant. On multivariate analysis, stone size and stone density were the independent factors affecting the outcome of SWL. Conclusions: The study demonstrated that stone size and density are significant and independent predictors of outcome in patients with upper ureteral stones. However SSD and signs of impaction still have to be evaluated