From the Guidelines
Yes, a 1 cm non-obstructing renal stone with an attenuation of 760 Hounsfield Units (HU) in a malrotated right kidney with a duplex collecting system is indicated for Extracorporeal Shock Wave Lithotripsy (ESWL) as the first-line treatment according to the European Association of Urology (EAU) guidelines for stones <2 cm 1.
Key Points
- The EAU guidelines recommend ESWL as the first-line treatment for pediatric patients with kidney stones less than 2 cm 1.
- The stone size of 1 cm is within the recommended range for ESWL, with a reported stone-free rate (SFR) of 90% for stones of this size 1.
- The attenuation of 760 Hounsfield Units (HU) is not a contraindication for ESWL, and the malrotated right kidney with a duplex collecting system does not preclude the use of ESWL.
- Flexible ureteroscopy (FURS) is a secondary option for upper tract stones according to EAU guidelines due to the lack of high-level evidence on the subject, despite reportedly higher success rates 1.
Treatment Considerations
- ESWL has been used for several years in children with no reported long-term complications 1.
- The use of FURS is increasing in pediatric patients, but more evidence is needed to support its use as a first-line treatment for upper tract stones 1.
From the Research
Stone Characteristics
- The stone in question has an attenuation of 760 Hounsfield Units (HU) 2, 3, 4, 5, 6
- Studies have shown that stones with lower attenuation values are more likely to be successfully fragmented by Extracorporeal Shock Wave Lithotripsy (ESWL) 2, 3, 4, 5, 6
Predictive Factors for ESWL Success
- Stone density, as measured by Hounsfield Units (HU), is a significant predictor of ESWL success 2, 3, 4, 5, 6
- A stone with an attenuation of 760 HU is below the threshold of 815 HU, 970 HU, and 1000 HU, which have been identified as predictive of poor outcomes in various studies 3, 4, 6
- The size of the stone (1 cm) is also a factor, with smaller stones being more likely to be successfully fragmented by ESWL 2, 5
Specific Studies
- A study published in 2005 found that stones with attenuation values of ≤ 750 HU had a higher clearance rate (88%) compared to stones with attenuation values of > 750 HU (65%) 2
- A study published in 2015 found that treatment success rates were significantly higher for stones with attenuation values of < 815 HU compared to stones with attenuation values of > 815 HU 3
- A study published in 2012 found that a stone density of 970 HU was a sensitive and specific threshold for predicting ESWL outcome, with stones below this threshold having a higher stone-free rate (96%) compared to stones above this threshold (38%) 4