Why can nephrostomy tubes be removed after antegrade ureteric stent (ureteral stent) insertion in a patient with obstructive uropathy due to tumor compression?

From the Guidelines

The nephrostomy tubes can be removed because the ureteric stents have successfully restored urinary drainage from the kidneys to the bladder, bypassing the obstruction caused by tumor compression. The nephrostomy tubes were initially placed as a safety measure to ensure adequate urinary drainage while confirming that the ureteric stents are functioning properly 1. The capping trial over 8-12 hours, followed by observation over the weekend, serves as a test to verify that urine is flowing adequately through the stents without requiring the external nephrostomy drainage. If the patient tolerates this capping period without signs of obstruction (such as pain, fever, or rising creatinine), it confirms that the internal drainage system via the stents is sufficient.

This approach is supported by recent studies, including a prospective randomized trial that demonstrated the safety and efficacy of percutaneous antegrade ureteral stenting with or without safety nephrostomy in patients with advanced cervical carcinoma and decreased estimated glomerular filtration rate <15 1. Additionally, the use of ureteral stents has been shown to be effective in treating malignant ureteral obstruction, with tandem double-J ureteral stents being used in some cases 1.

The staged approach to nephrostomy removal is standard practice in interventional radiology to ensure patient safety while transitioning from external to internal drainage. The 4-day observation period allows enough time to detect any potential complications before removing the safety nephrostomy tubes completely, reducing the risk of emergent reintervention for recurrent obstruction. Key considerations in this process include:

• Monitoring for signs of obstruction, such as pain, fever, or rising creatinine
• Ensuring adequate urinary drainage through the ureteric stents
• Gradually transitioning from external to internal drainage to minimize the risk of complications
• Close clinical and imaging follow-up to detect any potential issues early on 1.

From the Research

Nephrostomy Tube Removal

The nephrostomy tubes can be removed because the patient has undergone bilateral antegrade ureteric stent insertion, which allows for internal drainage of the urinary system.

• The antegrade ureteric stents are used to bypass the obstruction caused by the tumor compression, as described in the study by 2.
• The presence of the stents enables the patient's urinary system to drain internally, reducing the reliance on the nephrostomy tubes for drainage.
• As the patient is able to tolerate the capping of the nephrostomy tubes over the weekend, it indicates that the internal drainage system is functioning effectively, and the nephrostomy tubes are no longer necessary.
• The removal of the nephrostomy tubes is a common practice in patients with ureteral obstruction, as seen in the study by 3, where patients with ureteral obstruction underwent placement of transileal conduit retrograde nephroureteral stents, followed by removal of the antegrade nephrostomy catheter.

Indications for Nephrostomy Tube Removal

The indications for nephrostomy tube removal include:

• Successful internal drainage of the urinary system, as indicated by the patient's ability to tolerate capping of the nephrostomy tubes.
• Resolution of the obstruction, either through the placement of ureteric stents or other interventions.
• Absence of complications, such as infection or bleeding, that would require continued use of the nephrostomy tubes, as discussed in the study by 4.
• Patient's overall clinical condition, including the presence of any underlying medical conditions that may affect the decision to remove the nephrostomy tubes, as mentioned in the study by 5.

Considerations for Nephrostomy Tube Removal

The decision to remove the nephrostomy tubes should be made on a case-by-case basis, taking into account the individual patient's condition and medical history.

• The study by 6 highlights the importance of considering the risk of bacteremia and infection when removing nephrostomy tubes, particularly in patients with underlying medical conditions.
• The patient's ability to tolerate the capping of the nephrostomy tubes and the presence of internal drainage systems, such as ureteric stents, are important factors in determining the suitability for nephrostomy tube removal.