What it is (overview)

Nephrostomy placement with imaging guidance is a minimally invasive procedure that creates a temporary drainage pathway for urine directly from a kidney. A thin tube called a nephrostomy catheter is inserted through the skin of the back into the kidney’s collecting system so urine can drain into an external bag (or sometimes into the bladder depending on the setup). It is typically performed by an interventional radiologist or urology team.

The key feature of this procedure is imaging guidance—most commonly ultrasound and/or fluoroscopy (real-time X-ray)—to safely and accurately guide the needle and catheter into the correct location. Imaging also helps confirm proper catheter placement and urine flow, and it can identify the level of blockage.

Although it’s often called a “test,” nephrostomy placement is both diagnostic and therapeutic:

What it “measures” or evaluates: whether urine can drain from the kidney and how severe a urinary obstruction is. During the procedure, contrast dye may be used under fluoroscopy to outline the kidney and ureter (sometimes called an antegrade study), providing detailed information about where the blockage is.

What the results mean in plain language:

If the catheter drains urine well and imaging shows the urine pathway is open, it suggests the kidney can be decompressed and pressure is relieved. If drainage is poor or imaging shows a tight narrowing or complete blockage, it confirms a significant obstruction that may need further treatment (such as stone removal, ureteral stent placement, or treatment of a tumor/stricture). Successful drainage can protect renal function, reduce pain and swelling in the kidney (hydronephrosis), and help treat or prevent infection.

When & why it's usually done

A doctor may recommend nephrostomy placement with imaging guidance when urine cannot flow normally from the kidney to the bladder or when urgent decompression is needed. It is commonly used when a blockage threatens kidney function, causes severe symptoms, or is associated with infection.

Common reasons it’s ordered or performed include:

Relieve urinary obstruction: When the ureter is blocked by kidney stones, scarring, inflammation, or external compression. Imaging guidance helps locate the safest access route and confirm accurate catheter placement.

Protect kidney (renal) function: Ongoing obstruction can raise pressure inside the kidney and reduce filtration. Nephrostomy drainage can help preserve kidney function while the underlying cause is treated by urology or oncology.

Emergency treatment for infection with blockage: If a person has fever, chills, flank pain, or sepsis due to an infected obstructed kidney (obstructive pyelonephritis/pyonephrosis), urgent drainage via nephrostomy may be life-saving.

When a ureteral stent cannot be placed: Sometimes a standard internal stent placed through the bladder is not possible due to anatomy, tumor obstruction, or severe narrowing. A nephrostomy provides an alternate route for drainage.

Before or after urology procedures: It may be used to provide access for future treatments (for example, stone procedures) or to support healing after surgery. In some cases it can be used for imaging of the urinary tract under fluoroscopy.

Symptoms and situations that often lead to this procedure: severe flank/back pain, nausea/vomiting from renal colic, decreased urine output, new or worsening hydronephrosis on ultrasound/CT, rising creatinine or declining renal function on blood tests, recurrent urinary tract infections, fever with suspected urinary obstruction, or known cancer causing ureteral compression.

Common diseases related to it

• Kidney stones (nephrolithiasis) and ureteral stones causing obstruction
• Hydronephrosis due to urinary tract obstruction
• Obstructive uropathy (blocked urine flow affecting renal function)
• Ureteral stricture (narrowing from scarring, prior surgery, or inflammation)
• Urinary tract infection with obstruction, including pyelonephritis and pyonephrosis
• Bladder cancer, cervical cancer, prostate cancer, or other pelvic tumors compressing the ureter
• Retroperitoneal fibrosis causing ureteral compression
• Congenital urinary tract abnormalities (in select cases) leading to blockage
• Blood clots or sloughed tissue blocking the urinary tract (less common)

Health goals where it may help

• Restoring urine flow to relieve a urinary obstruction and reduce kidney swelling (hydronephrosis)
• Preserving or improving renal function by decompressing the kidney
• Reducing pain and pressure related to blocked urine flow (renal colic or flank pain)
• Treating or preventing serious infection by enabling drainage of an infected obstructed kidney
• Supporting urology care planning, including enabling catheter placement for stone treatment or further imaging
• Stabilizing health before surgery, chemotherapy, or other treatments when obstruction is present
• Monitoring ongoing drainage needs and ensuring safe urinary diversion when long-term obstruction cannot be immediately corrected