Renal Stone Density: Determinant of ESWL Success

Abstract

Background: The worldwide prevalence of developing renal stones is as high as 15% with an estimated 1 in every 5 persons being affected with the condition in Pakistan. Among the many treatment options available for renal calculi, extracorporeal shockwave lithotripsy (ESWL) is among the commonest owing to its non-invasive nature, however, it has its drawbacks; one being limitation against dense stones. 
 Objective: To assess association between stone density (detected on CT KUB) and ESWL outcome among patients with renal calculi.
 Methodology: This clinical trial was conducted upon a sample of 150 patients (of either gender, aged 16 to 70 years) presenting to the Urology out-patient, emergency and lithotripsy department of Ziauddin University Hospital with renal calculi from 30th August 2017 to 30th September 2019. After taking written informed consent, data was recorded onto a prestructured questionnaire containing inquiries pertaining to basic biodata, sociodemographic details, and disease history, inferences obtained from C.T KUB, operative notes and the eventual treatment outcome. The data obtained was analyzed using SPSS v. 21.0. 
 Results: The mean age of the sample stood at 36.7 (SD ± 3.1). 104 (69.3%) patients had multiple calculi and 46(30.7%) have single calculi with mean density of 812 (SD ± 219) HU. A (having stone density <500-HU) group B (having stone density 501 to 1000-HU) and group C (having stone density >1000-HU). The success of group A was 95.34% group B was 88.5% and group C was 80.3%. Major proportion of the sample (39.3%) required up to 3 ESWL sessions. The stone density was observed to be inversely proportional to the success of ESWL. 
 Conclusion: After careful consideration, it can be concluded that higher stone density is associated with a poor ESWL outcome and thus other treatment modalities may be considered among patients with a stone density of more than 900 HU.