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Preoperative stone attenuation value predicts success after shock wave lithotripsy in children

Sean McAdams1, Nicholas Kim, Daniel Dajusta

  • 1Department of Urologic Surgery, University of Minnesota Medical Center and Amplatz Children's Hospital, Minneapolis, Minnesota, USA.

The Journal of Urology
|August 24, 2010
PubMed

Insights

Kidney stone attenuation, measured in Hounsfield units (HU), predicts shock wave lithotripsy success in children. Stones below 1,000 HU are more likely to fragment, guiding treatment decisions.

Area of Science:

  • Urology
  • Medical Imaging

Background:

  • Shock wave lithotripsy (SWL) is a common treatment for pediatric kidney stones.
  • Predicting SWL success is crucial for effective patient management.
  • Previous research indicated stone attenuation predicts SWL success in adults, but data in pediatric populations was limited.

Purpose of the Study:

  • To evaluate if preoperative stone attenuation on noncontrast computerized tomography (CT) can predict shock wave lithotripsy (SWL) fragmentation in pediatric patients.
  • To address the lack of studies on this predictive parameter in the pediatric population.

Main Methods:

  • A multi-institutional review of 53 pediatric patients (1-18 years) treated with SWL for renal calculi (3.8-36.0 mm).
  • Stone size, skin-to-stone distance, and attenuation (HU) were measured using bone windows on preoperative noncontrast CT.
  • Success was defined as stone-free status within 12 weeks post-SWL without further intervention.

Main Results:

  • Overall, 62% of patients were stone-free after SWL.
  • Mean stone attenuation was significantly lower in successfully treated patients (710 ± 294 HU) compared to those with incomplete fragmentation (994 ± 379 HU; p = 0.007).
  • Stone attenuation <1,000 HU predicted SWL success (77% success rate vs. 33% for stones ≥1,000 HU; p <0.003).

Conclusions:

  • Preoperative stone attenuation <1,000 HU is a significant predictor of SWL success in pediatric patients.
  • This finding suggests attenuation values have similar predictive utility in children as previously reported in adults.
  • Stone attenuation measurement can aid in optimizing SWL treatment planning for pediatric kidney stones.
Abstract

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