Predicting the fragility of renal calculi in response to shock wave lithotripsy through their radiographic appearance

  • Mohamed Ali ElkoushyEmail author
  • M. Nady
  • A. Abdel Hafez
  • E. Salah
Original Article



To evaluate the radiological characteristics of renal stones on plain X-ray film of the kidneys, ureters and bladder (KUB) area as predictors of stone fragility during shock wave lithotripsy (SWL).

Patients and Methods

This prospective study included 336 patients who had a single renal pelvic stone ≤20 mm and were managed by SWL at 3 different centers. The patients were classified according to the radiological appearance of the stone on KUB film in terms of homogeneity, smoothness of the outline, and radiodensity in comparison to the last rib. The primary endpoint was the stone-free rate (SFR) within 3 months post-SWL. Multivariate regression analysis was used to compare the results.


The overall SFR was 71.43%. SFR was significantly higher in heterogeneous compared with homogenous stones (86% vs. 53%; p<0.01) and in rough compared with smooth surface calculi (77% vs. 61%, p<0.01). SFRs for stones with density less than, similar to or higher than that of the last rib were 82%, 69% and 56%, respectively (p<0.01). Multivariate analysis showed a positive proportional relationship between stone fragility (SWL outcome) and one or more favorable radiological criteria.


The radiological characteristics of renal calculi could predict their fragility after SWL. Stones which were heterogeneous, rough, or less dense than the last rib on KUB film were more likely to disintegrate during SWL.

Key Words

Shock wave lithotripsy renal calculi radiography urolithiasis 


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Copyright information

© PAUSA and Springer Verlag France 2011

Authors and Affiliations

  • Mohamed Ali Elkoushy
    • 1
    Email author
  • M. Nady
    • 2
  • A. Abdel Hafez
    • 3
  • E. Salah
    • 2
  1. 1.Department of UrologySuez Canal UniversityIsmailiaEgypt
  2. 2.Department of UrologyAl-Azhar UniversityAssiutEgypt
  3. 3.Department of UrologySohag UniversitySohagEgypt

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