Nephrostomy change

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Author: Mikael Häggström [notes 1]

The following procedure refers to the replacement of a transcutaneous pigtail catheter where the tip is intended to be in the renal pelvis.

Main steps

Various settings of a pigtail catheter with locking string, obturator (also called stiffening cannula) and puncture needle.
A. Overview
B. Both puncture needle and obturator engaged. (not used in nephrostomy change)
C. Puncture needle retracted. Obturator engaged. In nephrostomy change, remove any puncture needle before the intervention
D. Both obturator and puncture needle retracted, when the catheter is in the renal pelvis.
E. Locking string is pulled (bottom center) and then wrapped and attach to the superficial end of the catheter.

* denotes the steps that should be done in fluoroscopy.


  • Consider ensuring that a senior colleague is available for assistance if needed.
  • Engage the obturator of the catheter, but loose enough so that you can remove it with one hand if needed.
  • Position the patient on the side

Time usually allotted: 30 minutes.[1]

Coagulation: Low risk of bleeding

This procedure counts as conferring a relatively low risk of clinically significant bleeding.[2]

Required lab test

None necessary.

Lab interpretation

  • If prothrombin time has been tested, INR should be corrected if over 2.0
  • If partial thromboplastin time (aPTT or APTT) has been tested, it should be corrected if over 1.5 times its normal upper limit.
  • If platelet count has been performed, transfusion is indicated if it is below 50 x 109/L (equals 50,000/µL).

Anticoagulant medication

  • Coumarin (warfarin): Normally stop 3-5 days before, in order to reach INR ≤ 2.0
  • Low-molecular-weight heparin (LMWH): Stop 1 preceding dose
  • Dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis) and edoxaban (Savaysa, Lixiana):
  • Glomerular filtration rate over 30 ml/min: Stop 24 hours before
  • Glomerular filtration rate less than 30 ml/min: Stop 48 hours before
  • Clopidogrel (Plavix), prasugrel (Efient), ticagrelor (Brilinta, Brilique, and Possia): Stop 5 days before
  • Dipyridamole (Persantine): Stop 48 hours before
  • NSAIDs (including aspirin): No need to stop

Removal of previous catheter

Insertion of new catheter

  • Insert the new catheter with obturator over the guidewire,[notes 4] keeping the same direction as the guidewire through the tissues to avoid pulling or kinking it.*
  • Enter the renal pelvis with the obturator, and then advance with only the soft catheter.*
  • Confirm proper location within the renal pelvis by injection of a few ml of contrast, with two projections from different directions.*
  • Fixate the pigtail of the catheter.
  • Confirm functionality by injection of a few ml of contrast, looking for spontaneous dripping from the catheter when left open, as well as aspiration of the contrast.*
    Check whether there is blood or pus in the aspirate or spontaneous return.
  • Attach the outside end of the catheter to a bag.[notes 5]
  • Fixate the catheter to the skin, preferably both directly at insertion as well as enough to the side to have a soft S-shaped bend of the catheter in order to give certain room for stretching without pulling the catheter.


Catheter in calyx

If a previous pigtail catheter is located in a calyx, push it in with a stiff guidewire (such as Amplatz). If this is not directly successful, try:

  • Push the catheter from different angles, and/or rotate.*
  • Use the stiffer end of the Amplatz wire.
  • Loosen the pigtail.[notes 2]

If this is not successful, possibly use a hydrophilic guidewire to reach the renal pelvis, on which to switch catheters.*

Cannot advance guidewire

This is probably because of kidney stones in the catheter. Possible measures:

  • Try a hydrophilic or smaller guidewire in order to get through the catheter.
  • Advance around the catheter with a larger tube.
  • If the catheter has been used for weeks, it can generally be pulled out, and a new catheter inserted through the same tunnel without any guidewire.
Catheter stuck

If a previous pigtail catheter can not be pulled out after loosening of the pigtail threads, it may help to cut off the pigtail threads by the external tip, or even cutting off the entire external tip, which may loosen the threads.


  • Position of the previous catheter.
  • Absence of complications, or a description thereof.
  • Type, size and position of the new catheter.
  • Color of urine. Signs of blood or pus, if suspected.
Previous/Old pigtail is located in an inferior calyx. It it pushed into the renal pelvis with an Amplatz guidewire, followed by change to a new 8 French pigtail catheter with locking string. No complications. Spontaneous return of clear urine.
This example is Public Domain, and can be copied without any need for author attribution.
See also: General notes on reporting


  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.
  2. 2.0 2.1 Often by loosening a thread that keeps the pigtail spiraled.
  3. Always keep at least one hand on the guidewire. The grip needs to be switched to just above the skin as the catheter tip exits.
  4. It is useful to let an assistant advance the catheter tip until reaching skin level, letting you keep the position of the guidewire.
  5. Plug it only if there is a clear plan to attach a bag at a specific later time.


  1. . Change of Nephrostomy. Brighton and Sussex University Hospitals. Publication Date: February 2018.
  2. The coagulation section follows local practice at: NU Hospital Group, Sweden