From the Guidelines
Percutaneous nephrostomy (PCN) is the best method for establishing temporary urinary drainage when the urinary tract is obstructed, with a technical success rate approaching 100% when performed with image guidance, as demonstrated by a large UK registry with data from over 3,000 PCN procedures 1.
Procedure Overview
This procedure involves inserting a catheter through the skin directly into the kidney under imaging guidance, typically using ultrasound and fluoroscopy. The procedure is usually performed under local anesthesia with sedation, making it less invasive than surgical alternatives.
Key Considerations
For optimal outcomes, the approach should target a posterior calyx, avoiding the renal vessels, colon, pleura, and liver. The standard technique uses an 8-14 French catheter, though size may vary based on the specific clinical situation. After placement, the catheter is secured to the skin and connected to a drainage bag.
Indications and Effectiveness
Patients typically require prophylactic antibiotics such as a single dose of cefazolin 1-2g IV before the procedure, especially if infection is suspected. Nephrostomy is particularly effective for managing conditions like obstructive uropathy from stones, tumors, or strictures, as well as for urinary diversion in cases of urine leaks. This approach is preferred because it provides immediate decompression of the collecting system, can be performed quickly in urgent situations, and has lower morbidity compared to surgical alternatives, as noted in the ACR Appropriateness Criteria for radiologic management of urinary tract obstruction 1.
Complications and Monitoring
Potential complications include bleeding, infection, and catheter dislodgement, so regular monitoring and catheter care are essential post-procedure. The Society of Interventional Radiology quality improvement (SIR QI) guidelines set threshold percentages for technical success rates for PCN, with complication rates related to PCN generally reported at 10% or lower 1.
Clinical Guidelines
The SIR QI guidelines have suggested thresholds for PCN complications, including septic shock at 4%, and provide a framework for evaluating the effectiveness and safety of PCN in various clinical scenarios 1. Overall, PCN is a safe and effective technique with limited morbidity and mortality, making it a preferred method for managing urinary tract obstruction, as supported by the ACR Appropriateness Criteria and other clinical guidelines 1.
From the Research
Methods for Percutaneous Nephrostomy (PCN)
The best method for percutaneous nephrostomy (PCN) involves the use of imaging guidance to insert a catheter into the renal collecting system. The following methods are commonly used:
- Ultrasound-guided PCN: This method uses ultrasound to guide the insertion of the catheter and has the advantages of showing the localization of the renal cavities and the depth of the kidney, and can be used during pregnancy and in subjects with allergy to contrast medium or with reduced renal function 2.
- Fluoroscopy-guided PCN: This method uses fluoroscopy to guide the insertion of the catheter and is often used in combination with ultrasound guidance to guarantee a success rate exceeding 98% 2.
- CT-guided PCN: This method uses computed tomography (CT) to guide the insertion of the catheter and is particularly useful in complex clinical scenarios, such as obese patients, non-dilated uropathy, and critically ill patients 3.
Techniques for PCN
The following techniques are commonly used for PCN:
- Seldinger's access technique: This technique involves explorative puncture of the renal cavity with a 22 G needle, followed by the insertion of a metal wire and then a catheter 2.
- One-step access technique: This technique involves the insertion of a catheter over a guide wire in a single step.
- Mixed access technique: This technique involves a combination of Seldinger's and one-step access techniques.
Imaging Guidance Modalities
The following imaging guidance modalities are commonly used for PCN:
- Ultrasound: This modality is useful for guiding the insertion of the catheter and can be used in real-time to monitor the procedure 2, 4.
- Fluoroscopy: This modality is useful for guiding the insertion of the catheter and can be used in combination with ultrasound guidance to guarantee a success rate exceeding 98% 2, 4.
- CT: This modality is useful for guiding the insertion of the catheter in complex clinical scenarios, such as obese patients, non-dilated uropathy, and critically ill patients 3.
Outcomes
The outcomes of PCN are generally good, with technical success rates ranging from 90% to 98% 2, 5, 3. The complication rate is generally low, ranging from 3.6% to 15% 2, 5, 3. The 30-day mortality rate is generally low, ranging from 5.2% to 7% 3.