IS Case 191: Ureteral obstruction

Samuel Madoff, MD


Imaging Sciences URMC 2008
Publication Date: 2009-05-22

History

Patient is a 43-year-old male with right flank pain.

Diagnosis

Ureteral obstruction

Discussion

This case illustrates the primary indication for nephrostomy tube placement, ureteral obstruction. The source of obstruction may be benign (stone, clot or sloughed papilla) or malignant (ureteral transitional cell carcinoma, bladder or prostate carcinoma). Notably, bladder or prostate carcinoma may cause bladder outlet obstruction as well. Extrinsic ureteral compression by metastases (colon, breast, lymphoma, etc.) or retroperitoneal fibrosis can also cause obstruction. Other indications include iatrogenic ureteral injury, ureteral fistulas and treatment for complications related to renal transplants.

Percutaneous nephrostomy is undertaken after informed consent, inspection of lab values (i.e. coagulation panel, hematocrit, etc.), review of available imaging and pretreatment with antibiotics.

Briefly, the procedure involves image-guided (often ultrasound) access to the renal collecting system, optimally via a posterior lower or middle pole calyx. Once access is achieved, a urine sample may be collected for culture and laboratory analysis.

After tract dilation, the drainage tube (usually 8 French) is placed over a wire. A larger tube (10 or 12 French) may be required in the setting of pyonephrosis given the thick drainage. The catheter tip is formed and locked in the renal pelvis. Catheter position is confirmed with contrast injection. Skin sutures are typically used to anchor the catheter.

Complications of percutaneous nephrostomy placement are infrequent with a rate of less than 4%. Hemorrhage and infection are the two complications most often necessitating treatment.

A small amount of hemorrhage is common, while larger quantities trigger consideration of arterial injury, an arteriovenous fistula or pseudoaneurysm. Percutaneous access via a calyx, rather than the renal pelvis directly, helps to prevent bleeding.

Patients are at risk of infection, particularly in the setting of pyonephrosis or urinary tract infection. Prophylactic antibiotics are standard to aid in avoiding infection. Distending or manipulating the collecting system as little as possible is recommended.

Other complications include catheter dislodgement or occlusion.

References

  1. Kaufman JA, Lee MJ. Vascular & Interventional Radiology: The Requisites. Philadelphia: Mosby, 2004:608-615.
  2. Pollard AJ, Nicholson DA. Percutaneous nephrostomy: how to do it. J Intervent Radiol. 1994;9:129-41.

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