Can a patient with a large stone at the ureterovesical junction (UVJ) and only one nephrostomy tube still urinate via the penis?

Can a Patient with a UVJ Stone and Nephrostomy Tube Still Urinate via the Penis?

Yes, a patient with a large stone at the ureterovesical junction (UVJ) and a nephrostomy tube in one kidney can still urinate via the penis, as urine from the unaffected kidney will continue to flow normally through its ureter into the bladder. 1

Anatomy and Physiology Explanation

When a patient has a large stone at the UVJ:

• The stone blocks urine flow from the affected kidney to the bladder
• A nephrostomy tube placed in this kidney allows urine to drain externally
• The unaffected kidney continues to produce urine that flows normally through its ureter to the bladder
• This urine collects in the bladder and can be expelled through the penis during urination

Management of Obstructing UVJ Stones

The American Urological Association guidelines clearly state that in patients with obstructing stones and suspected infection, urgent drainage of the collecting system is necessary 1. This can be accomplished through:

1. Nephrostomy tube placement - Creates direct external drainage from the affected kidney
2. Ureteral stent placement - Allows internal drainage around the stone

The choice between these options depends on:

• Patient's clinical condition
• Technical feasibility
• Surgeon preference
• Future treatment plans

Important Considerations

• Urinary output: Total urinary output through the penis may be reduced since approximately half of the urine (from the affected kidney) is being diverted through the nephrostomy tube
• Monitoring: The patient should monitor both nephrostomy tube output and urination through the penis
• Infection risk: Obstructing stones with infection require urgent drainage to prevent sepsis 1
• Stone location: UVJ is one of the most common locations for ureteral stones to become lodged, with studies showing approximately 46-60% of ureteral stones are found at this location 2, 3

Definitive Treatment Options

After initial drainage with the nephrostomy tube, definitive treatment options include:

• For stones ≤10 mm: SWL (shock wave lithotripsy) or URS (ureteroscopy) 1
• For stones >10 mm: URS is preferred over SWL due to higher stone-free rates 1
• For large stones (>20 mm): PCNL (percutaneous nephrolithotomy) may be considered 1

Common Pitfalls to Avoid

1. Assuming complete urinary obstruction: Even with a large UVJ stone, the contralateral kidney and ureter typically function normally
2. Delaying treatment: Obstructing stones with infection require urgent drainage to prevent sepsis 1
3. Inadequate pain management: Patients may still experience flank pain despite nephrostomy drainage if the stone continues to obstruct the ureter
4. Neglecting follow-up imaging: Regular imaging is essential to monitor stone position and potential passage

In summary, while the nephrostomy tube diverts urine from the affected kidney, the patient will continue to urinate normally through the penis from the unaffected kidney's output.