Can a urologist (Urologist) request simple ureteroscopy to extract a 16 mm renal caliceal stone or is complex ureteroscopy required?

Ureteroscopy for 16 mm Renal Caliceal Stone

For a 16 mm renal caliceal stone, complex ureteroscopy with flexible ureteroscope is required rather than simple ureteroscopy, as the stone size and location necessitate specialized equipment and techniques for successful removal. 1, 2

Stone Size and Treatment Selection Considerations

The approach to kidney stone management depends primarily on:

• Stone size
• Stone location
• Available equipment
• Surgeon expertise

Why Complex Ureteroscopy is Needed:

1. Stone Size Factor:

   • The American Urological Association guidelines recommend flexible ureteroscopy for stones between 10-20 mm 2
   • For stones >10 mm in the kidney, simple ureteroscopy is insufficient 1
   • A 16 mm stone falls into the category requiring more advanced techniques

2. Anatomical Considerations:

   • Renal caliceal stones require navigation through the ureter and into the kidney's collecting system
   • Simple ureteroscopy typically uses rigid or semi-rigid instruments which cannot effectively navigate to calyces 1
   • Complex ureteroscopy employs flexible ureteroscopes that can access the intrarenal collecting system 2

Technical Requirements for 16 mm Caliceal Stone

Equipment Needed:

• Flexible ureteroscope (essential for accessing renal calyces)
• Holmium:YAG laser for lithotripsy
• Stone retrieval devices (baskets)
• Ureteral access sheath (often necessary for repeated access)

Procedural Complexity:

• Stones >10 mm typically require fragmentation before extraction 1
• Multiple passes may be needed to clear all fragments
• Higher risk of complications compared to simple ureteroscopy for distal ureteral stones 1

Alternative Treatment Options

While complex ureteroscopy is appropriate, other options include:

1. Shock Wave Lithotripsy (SWL):

   • Less effective for stones >15 mm 2
   • Stone-free rates decline significantly with increasing stone size 3

2. Percutaneous Nephrolithotomy (PCNL):

   • First-line for stones ≥20 mm 4
   • More invasive but may be considered if ureteroscopy fails

Potential Complications

Complex ureteroscopy for proximal/renal stones carries higher risks than simple ureteroscopy:

• Ureteral injury (6%)
• Stricture formation (2%)
• Sepsis (3-4%)
• Urinary tract infection (4%) 1

Important Caveats

1. Never perform blind basketing:

   • All intraureteral manipulations must be under direct ureteroscopic vision 1
   • Fluoroscopic imaging alone is insufficient and dangerous

2. Pre-procedure preparation:

   • Urine culture is mandatory to rule out infection 2
   • Appropriate antibiotic therapy should be administered if infection is suspected 1

3. Post-procedure care:

   • Ureteral stent placement is often necessary 2
   • Follow-up imaging to confirm stone clearance

In summary, a 16 mm renal caliceal stone requires complex ureteroscopy with a flexible ureteroscope due to the stone size and location. Simple ureteroscopy would be inadequate for accessing and effectively treating a stone of this size in the kidney.