What are the measurements for proximal, middle, and distal ureterolithiasis (Ureteral Stones)?

From the Guidelines

Ureteroliths are classified based on their location in the ureter, with proximal stones located in the upper third, middle stones overlying the iliac vessels, and distal stones in the lower third, from below the iliac vessels to the ureterovesical junction, and the measurements for these locations are crucial in guiding management decisions. The location of the stone affects spontaneous passage rates and treatment approaches, with proximal stones having lower spontaneous passage rates (around 22-25%) compared to distal stones (45-50%) 1.

Key Considerations

• Proximal ureteroliths are located in the upper third of the ureter, from the ureteropelvic junction to the area where the ureter crosses the iliac vessels.
• Middle ureteroliths are found in the segment that overlies the iliac vessels.
• Distal ureteroliths are located in the lower third of the ureter, from below the iliac vessels to the ureterovesical junction.
• Stone size is a critical factor, with stones <5mm having higher spontaneous passage rates regardless of location 1.
• Accurate classification helps determine appropriate follow-up intervals and the urgency of intervention.

Treatment Approaches

• Proximal stones may require shock wave lithotripsy or ureteroscopy, while distal stones are often more accessible for ureteroscopic removal 1.
• For patients with mid or distal ureteral stones who require intervention, ureteroscopy (URS) is recommended as first-line therapy, with shock wave lithotripsy (SWL) as an alternative 1.
• The choice of treatment should be based on the location and size of the stone, as well as the patient's overall health and preferences.

Measurement and Documentation

• When measuring and documenting ureteroliths, it's helpful to note both the absolute location (distance from the ureteropelvic junction or ureterovesical junction) and the anatomical segment.
• Accurate measurement and documentation are crucial in guiding management decisions and determining the best course of treatment.

From the Research

Ureteral Stone Measurements

The measurements for proximal, middle, and distal ureterolithiasis are not explicitly stated in the provided studies. However, the studies do mention the size of the stones in relation to their location and treatment outcomes.

• The size of the stones can vary, with some studies mentioning stones as small as 3 mm 2 and as large as 15 mm 2 or 10 mm 3.
• One study mentions that 90% of ureteral calculi <4 mm are expelled over a period of 3 months, while those >6 mm have reduced elimination possibilities of 30% 3.
• Another study found that alpha-blockers may be less effective for smaller stones (5 mm or smaller) than for larger stones (greater than 5 mm) 4.
• The mean stone size in one study was 4.2 (2-10) mm 5.

Stone Location and Treatment

The location of the stone can affect treatment outcomes, with some studies focusing on distal ureteral stones 2, 3.

• One study found that tamsulosin increases the elimination of distal ureter lithiasis of <10 mm 3.
• Another study found that alpha-blockers may be more effective for larger stones (greater than 5 mm) 4.
• The use of medical expulsive therapy (MET) for ureterolithiasis can vary, with one study finding that 40% of patients with symptomatic ureterolithiasis were treated with MET on discharge from the ER 5.