Outcome of Extracorporeal Shock Wave Lithotripsy (ESWL) for High Density Renal Stones

Abstract

Objective: To compare the effects of extracorporeal shock wave lithotripsy (ESWL) in comparison with high-density renal stones (1000 Hounsfield units) with respect to stone-free rate, auxiliary procedures, and complications.

Methods: A total of one hundred and two consecutive adult patients having renal stones at most 20 mm in maximum dimension and density of 1000 HU or more with non-contrast computed tomography underwent ESWL with a third generation lithotripter. Four weeks after the last session, follow-up imaging (ultrasound imaging or X-ray KUB) was conducted. Stone-free rate which is total clearance or reduction insignificant residual stone (less than 4 mm) without further surgical intervention was the main outcome. Secondary outcome measures encompassed the need to use secondary procedures and complications. The analysis was conducted through the SPSS version 26.0, categorical variables are shown as frequencies and percentage with a confidence interval of 95% Wilson score and association by chi-square or Fisher exact test.

Results: Mean age was 41.2 ± 10.9 years and 71.6% of patients were male. Mean stone size was 13.2 ± 3.1 mm and mean density was 1185 ± 142 HU. The stone-free rate was 56.9% (58/102; 95% CI 46.9–66.4). Auxiliary procedures were required in 28.4% (29/102; 95% CI 20.1–38.1) and any complication occurred in 23.5% (24/102; 95% CI 16.0–33.0). Stone-free rate was significantly higher for stones ≤13 mm (69.1% vs 42.6%, p=0.009) and single-session treatment (75.6% vs 44.3%, p<0.001).

Conclusion: ESWL demonstrated a satisfactory stone-free rate in a well-selected patient with high-density renal stones, however, almost one-third of patients needed an auxiliary intervention in this Pakistani tertiary care population. Computerised tomography density must be done on pre-treatment and realistic counselling and resource allocation is a necessity.