From the Research
Ureteroliths are classified as proximal, middle, or distal based on their location within the ureter relative to spinal levels, with proximal ureteroliths located between the ureteropelvic junction and the upper border of the sacrum (L1-L3), middle ureteroliths between the upper border of the sacrum and the crossing of the iliac vessels (L3-L5), and distal ureteroliths between the crossing of the iliac vessels and the ureterovesical junction (S1-S3) 1.
Classification of Ureteroliths
The classification of ureteroliths is crucial for treatment planning, as the location affects spontaneous passage rates and intervention approaches.
- Proximal ureteroliths: located between the ureteropelvic junction and the upper border of the sacrum, typically corresponding to the L1-L3 vertebral levels.
- Middle ureteroliths: found between the upper border of the sacrum and the crossing of the iliac vessels, generally at the L3-L5 vertebral levels.
- Distal ureteroliths: positioned between the crossing of the iliac vessels and the ureterovesical junction, corresponding to the S1-S3 vertebral levels.
Importance of Classification
This classification is important for treatment planning, as proximal stones typically have lower spontaneous passage rates (around 22%) compared to distal stones (approximately 45%) 2. The anatomical narrowing at the ureterovesical junction, ureteropelvic junction, and iliac vessel crossing creates natural points where stones commonly become lodged.
Standardized Communication
When documenting ureteroliths on imaging, specifying the location relative to these spinal levels provides standardized communication between radiologists and urologists, facilitating appropriate management decisions 3.
Recent Evidence
A recent study published in 2021 found that medical expulsive treatment (MET) can play a certain role in the expulsion of lithiasis ≥ 5mm and ≤ 10 mm located in the distal ureter, although it has not been possible to demonstrate that any of the drugs used may have special superiority in terms of effectiveness 1.