Blocked Tube • Xray of the Week
To prevent obstruction, it is best to exchange nephrostomy tubes every 3 months. However, long term indwelling nephrostomy tubes may become occluded by urinary crystal deposition which can lead to encrustation and obstruction. What if the patient still needs the tube and you can't get a guide-wire through the tube? Can you still exchange it? Yes you can! Below is a step by step approach with diagrams that I drew myself.
Figure 1. A. Cut existing nephrostomy tube (in blue). B. Suture (in orange) through tube. C. Advance sheath (in red) over tube and the suture.
Figure 2. A. Keep advancing sheath (in red) over tube. B. Now sheath in collecting system. C. When sheath in collecting system, pull nephrostomy tube.
Figure 3. A. Keep pulling nephrostomy tube while holding sheath (in red) in place. B. Now sheath in collecting system. C. Advance wire (in black) through sheath.
Figure 4. A. Remove sheath, leaving wire in collecting system. B. Advance new nephrostomy tube (in purple) over the wire. C. Remove wire.
Indications for percutaneous nephrostomy include urinary diversion for urinary tract obstruction secondary to calculi, malignancy, or inflammation. It may also be requested by urologists for urinary fistula and/or leaks which may be due to traumatic or iatrogenic injury. I usually use a 10F tube as smaller tubes are more likely to become occluded. In the event of nephrostomy tube occlusion, the above technique has been very effective.
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Kevin M. Rice, MD is president of Global Radiology CME and serves as the Chief of staff and Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. Dr. Rice co-founded Global Radiology CME with Natalie Rice to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" award for the Most Effective Radiology Educator.
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