Is a 6 mm calculus in the left ureter, causing mild hydroureter and hydronephrosis, indicated for flexible ureteroscopy?

Management of a 6 mm Left Ureteral Calculus with Mild Hydroureter and Hydronephrosis

Flexible ureteroscopy is indicated for a 6 mm calculus in the left ureter at L3 level causing mild hydroureter and hydronephrosis, particularly with its high density (1568 HU) suggesting resistance to shock wave lithotripsy. 1

Treatment Approach for Ureteral Calculi

First-Line Treatment Options

• For a 6 mm ureteral stone causing hydronephrosis, active intervention is indicated rather than watchful waiting
• The 2007 AUA Guideline for Management of Ureteral Calculi supports ureteroscopy as an appropriate first-line therapy for stones of any size in the ureter 1
• Ureteroscopy has evolved into a safer and more efficacious modality with high stone-free rates (81-94%) depending on stone location 1

Why Flexible Ureteroscopy is Appropriate in This Case:

1. Stone Characteristics:

   • 6 mm size (intermediate size)
   • High density (1568 HU) - stones with higher attenuation values are often resistant to shock wave lithotripsy 1
   • Location at L3 level (proximal-mid ureter)
   • Causing obstruction (hydronephrosis)

2. Efficacy for This Location:

   • For proximal ureteral stones, flexible ureteroscopy achieves superior stone-free rates (87%) compared to rigid or semirigid ureteroscopy (77%) 1
   • For mid-ureteral stones (like this case at L3 level), ureteroscopic management has a high success rate of 86% 1

Procedural Considerations

Pre-Procedure Planning

• Obtain urine culture before treatment
• Administer a single dose of prophylactic antibiotic before the procedure 2
• Evaluate for any anatomical challenges that might affect access

Technical Aspects

• Modern flexible ureteroscopes (including smaller 6.3 Fr scopes) allow excellent access to all portions of the ureter 3
• Holmium:YAG laser lithotripsy is the preferred method for stone fragmentation 4
• Consider using a ureteral access sheath to facilitate multiple passages and reduce intrarenal pressure 5

Post-Procedure Care

• Follow-up imaging (ultrasound or KUB radiography) is recommended to confirm stone clearance 2
• Short-term ureteral stenting is typically required

Comparative Treatment Options

Shock Wave Lithotripsy (SWL) vs. Ureteroscopy

• SWL stone-free rates have declined for distal ureteral stones compared to previous analyses 1
• The high density of this stone (1568 HU) suggests resistance to SWL fragmentation 1
• For stones between 100-300 mm² (this 6 mm stone falls in this range), single treatment success rates are better for ureteroscopy (87.8%) compared to SWL (60.4%) 6
• SWL may require multiple treatments to achieve comparable success rates to ureteroscopy 6

Laparoscopic or Open Approaches

• Not indicated as first-line therapy for a 6 mm stone
• Reserved for cases where SWL and ureteroscopy have failed or are unlikely to succeed 1

Potential Complications and Their Management

• Ureteral perforation rates with modern ureteroscopy are less than 5% 1
• Long-term complications such as stricture formation occur with an incidence of 2% or less 1
• Proper technique remains the most important factor for successful outcomes 1

Follow-Up Recommendations

• Confirm stone clearance with follow-up imaging
• Consider metabolic evaluation to prevent recurrence
• Increase fluid intake to more than 2L/day to help prevent recurrent kidney stones 2

In conclusion, flexible ureteroscopy represents the optimal approach for this 6 mm ureteral calculus with its high density and associated hydronephrosis, offering high success rates with minimal morbidity.