What it is (overview)

A Nephrostomy Exchange with Imaging Guidance is a minimally invasive procedure used to replace (exchange) an existing nephrostomy tube. A nephrostomy tube is a small drainage catheter that goes through the skin of your back into the kidney’s collecting system to help urine drain when there is a blockage in the urinary tract. This tube allows kidney drainage when urine can’t flow normally through the ureter to the bladder.

The exchange is performed with imaging guidance—most commonly fluoroscopy (real-time X-ray) and/or ultrasound—to confirm the tube’s position, maintain safe access to the kidney, and ensure urine drains properly. Contrast dye may be used during fluoroscopy to outline the kidney and ureter and to check for narrowing, blockage, or leakage.

This is not a “blood test” with numeric lab values. Instead, the “results” are based on what the imaging shows and how well the new tube functions. In plain language, typical results may include:

Normal/expected findings: the new nephrostomy tube sits in the correct part of the kidney, urine flows freely through the tube, and imaging shows no new obstruction or leak.

Abnormal findings: imaging may show persistent or worsening obstruction, tube kinking or malposition, poor drainage, stone fragments, or signs of infection/collection. These findings may lead to additional treatment such as tube repositioning, upsizing, flushing, antibiotics, or evaluation for a ureteral stent or definitive stone/tumor treatment.

When & why it's usually done

Doctors typically order or schedule a nephrostomy tube exchange when a person already has a nephrostomy in place and needs it replaced to keep the urinary tract draining safely. Nephrostomy tubes can clog, shift, crack, or become a source of infection over time, so routine exchanges are often planned.

This procedure is usually done to:

Maintain kidney function and renal health: Ongoing blockage can raise pressure in the kidney (hydronephrosis) and cause kidney damage. Reliable drainage helps protect the kidney.

Manage a urinary tract blockage: Common causes include kidney stones, ureteral strictures (narrowing), tumors compressing the ureter, or scarring after surgery or radiation.

Prevent or treat complications of the existing tube: Tube blockage from debris or encrustation, urine leakage around the tube, reduced drainage, or accidental dislodgement often requires prompt exchange.

Evaluate the urinary tract during exchange: Imaging guidance (ultrasound/fluoroscopy) can help the care team assess where the blockage is, how severe it is, and whether urine is draining appropriately.

Your clinician may recommend an exchange sooner than scheduled if you develop symptoms suggesting a problem with kidney drainage or infection, such as:

Fever or chills, flank/back pain, foul-smelling or cloudy urine, redness/pus at the skin site, decreased urine output from the tube, new leakage around the tube, nausea/vomiting, or worsening kidney function on blood tests (for example, rising creatinine).

Common diseases related to it

• Urinary tract obstruction (blocked urinary tract)
• Hydronephrosis (swelling of the kidney from urine backup)
• Kidney stones (nephrolithiasis) and ureteral stones
• Ureteral stricture (narrowing/scarring of the ureter)
• Urinary tract infection (UTI) and pyelonephritis (kidney infection)
• Obstructive uropathy causing acute kidney injury (AKI) or worsening chronic kidney disease (CKD)
• Bladder cancer, cervical cancer, prostate cancer, or other pelvic/abdominal tumors causing ureteral compression
• Post-surgical or radiation-related ureteral injury/obstruction
• Neurogenic bladder with secondary urinary retention and upper-tract dilation (in select cases)

Health goals where it may help

• Protecting kidney function by ensuring reliable kidney drainage
• Relieving symptoms from urinary tract blockage (pain, pressure, reduced urine flow)
• Reducing risk of kidney infection and sepsis by maintaining unobstructed urine drainage
• Supporting cancer care when a tumor causes ureteral obstruction (preserving renal function for treatment)
• Monitoring and maintaining long-term nephrostomy tube performance and comfort
• Preventing complications such as hydronephrosis, recurrent obstruction, or tube dislodgement