Indications for Percutaneous Nephrostomy in Patients with Calculi
Percutaneous nephrostomy (PCN) is primarily indicated in patients with kidney stones when there is evidence of obstructive uropathy complicated by infection, especially pyonephrosis or sepsis, as well as for patients with declining renal function due to obstruction. 1
Primary Indications
- Obstructive uropathy with infection/pyonephrosis: The most critical indication for PCN is urinary tract obstruction complicated by infection, particularly when there is evidence of pyonephrosis (infected, obstructed kidney) or gram-negative septicemia 2
- Declining renal function: PCN is beneficial when there is evidence of worsening renal function due to obstruction from calculi 1
- Pre-procedural drainage: PCN is indicated as the initial step before percutaneous nephrolithotomy (PNL) for large staghorn calculi 1
- Failed SWL therapy: When shock wave lithotripsy (SWL) fails to adequately treat stones, PCN followed by PNL is often the recommended approach rather than additional SWL 3
Stone-Specific Indications
- Staghorn calculi: PCN is typically the first step in the management of staghorn calculi, with subsequent PNL being the preferred treatment approach 1
- Complex stone disease: For complex stone disease including staghorn calculus, PCN provides access for subsequent stone removal 1
- Large stones (>2cm): PCN followed by PNL is recommended for kidney stones larger than 2 cm 4
- SWL-resistant lower pole stones >1cm: PCN with subsequent PNL is indicated for lower pole stones greater than 1 cm that are resistant to SWL 4
Technical Considerations
- Access planning: PCN provides optimal access for subsequent PNL, with technical success rates approaching 100% when accessing dilated collecting systems 1
- Drainage establishment: When SWL is planned for staghorn calculi, adequate drainage via PCN should be established before treatment to facilitate fragment passage and prevent severe obstruction and sepsis 1
- Prediction of renal function recovery: PCN can be used to predict recoverable renal function in cases of longstanding obstruction by assessing the response of renal plasma flow rate to decompression 2
Procedural Success and Safety
- Technical success rates: PCN placement has high technical success rates—approximately 95% for urinary obstruction without stones and 85% for complex stone disease including staghorn calculus 1
- Complication rates: Complication rates related to PCN are generally low (approximately 10% in most series, with UK registry data showing even lower rates at 6.3%) 1
- Common complications: The most common adverse events are catheter displacement, bleeding, and sepsis 1
- Bleeding risk: Mild hematuria occurs in approximately 50% of patients after PCN, but clinically significant bleeding is less common 1
Special Considerations and Caveats
- Nondilated collecting systems: Technical success rates are lower (80-90%) when accessing nondilated systems compared to dilated systems (>95%) 1
- Risk factors: Potential risk factors for postprocedural sepsis include diabetes and renal calculi, though these have not been definitively shown to be predictive of infection 1
- Outpatient procedures: Although often performed as an inpatient procedure, PCN can be performed safely in selected low-risk patients as an outpatient procedure with same-day discharge 1
- Imaging guidance: Most operators use ultrasound for initial access and then fluoroscopy to place the nephrostomy tube 1
By providing urgent decompression in obstructed and infected systems, PCN has been shown to reduce mortality from gram-negative septicemia from 40% to 8% and to reduce hospitalization length by half in patients with severe infection complicating urinary tract obstruction 2.