A Prospective Longitudinal Study onthe Predictability of Quadruple-D Score in the Success Rate of Extracorporeal Shock Wave Lithotripsy for Renal Stones 1-2cm in Diameter

Abstract

Introduction: Quadruple-D, based on Computed Tomography (CT) derived metrics, is a scoring system that helps urologists to predict the Stone Free Rate (SFR) following Extracorporeal Shock Wave Lithotripsy (ESWL) in renal stones. Aim: To evaluate the efficacy of Quadruple-D scoring system to assess the SFR in individuals with renal stones measuring 1-2 cm in diameter after giving ESWL. Materials and Methods: The study was conducted on 120 patients. Systemic random sampling technique was applied with a sampling interval of two. Quadruple-D scoring, comprising of four Computed Tomography (CT) based metrics that is stonedimension, stone density, Hounsfield units (HU), Skin-to-Stone Distance (SSD) and stone location, was done prior to ESWL. The scores ranged from zero (worst) to four (best) points. Plain abdominal radiography was done three weeks after ESWL to assess SFR. Complete clearance was considered the stone free status. Patients were divided into group A with complete stone clearance and group B with residual stone. All the statistical analysis was done using IBM SPSS 26.0. Student’s t-test or Mann-Whitney U-test was used to compare continuous variables. Fisher’s-exact test and Chi-square test were used to analyse the cross charts between two categories. Results:The mean ellipsoid Stone Volume (SV) was 396.44±163.23 mm3 and 395.81±227.52 mm3 in group A and B, respectively. The stone density was 724.28±210.90 in group A and 814.56±190.63 in group B. In group A, 9.20% and in group B, 34.09% of the patients had stones in lower calyx. The difference between the groups based on the above parameters were statistically significant. The Quadruple-D score was 2.09±0.65 and 1.54±0.79 in group A and B, respectively. The Area Under the Curve (AUC) of Quadruple-D scoring system was 0.674. The age, sex, BMI, laterality of the stone and SSD did not predict stone-free status in this study. Conclusion: Quadruple-D scoring system has been successfully validated as the SFR showed a parallel increase with every positive component. Quadruple-D is an easy to use clinical tool to predict the success rate of ESWL.