Double J Placement Methods Comparative Analysis

Excerpt

Every urologist seems to have his own unique and personal procedure for double J stent placement as there is no single, universally accepted, or recommended technique. Some practitioners will immediately cut the dangler/safety thread, which gets the thread out of the way early in the placement procedure but may cause difficulties later in adjusting or manipulating the stent. Some will choose to use the same length stent for every patient or adjust the length based on estimates from retrograde pyelograms using x-ray, CT scans, or patient height which seems less than ideal if the placement of an optimal length stent is the goal. An optimized double J placement technique has not been agreed upon.

The ideal double J placement technique would be reversible, include an accurate and reliable ureteral measurement for optimal stent length selection, and would guarantee ureteral guidewire access throughout the procedure. The technique should emphasize patient comfort and safety while maintaining ureteral access throughout the procedure. Further, the procedure should be as close to mistake-proof as possible since, for many new urology residents, double J stent placement is among their first endoscopic surgeries.

We started by performing a detailed critical analysis of the various techniques of double J stent placement described in the literature, as well as many other variations that have never been formally reported.

We found answers to many of the more common questions including the best way to select the optimal stent length, use of rigid versus soft stent material, whether to go longer or shorter if the measured ureteral length is in between sizes, management of standard stent side effects and complications, when double J stents can be safely omitted after ureteroscopic lithotripsy procedures, etc.

Features of an Optimal Double J Stent Placement Technique: Basic Principles

Use the right length ureteral stent.While the length of the ureter can be estimated by CT, retrograde x-ray, or by the patient's height, it is best to measure the ureteral length directly if possible. Nothing else gives an accurate, reliable ureteral length measurement. The patient's height can only provide a vague approximation, and a typical x-ray pyelogram will overestimate the length by about 10% due to x-ray dispersion from the magnification effect between the patient and the image intensifier.

To obtain an accurate ureteral length measurement, a 5 or 6 French open-ended catheter is placed into the renal pelvis over a guidewire. A small amount of diluted contrast injected retrograde into the open-ended ureteral catheter is sufficient to visualize the renal pelvis. If the renal pelvis becomes too opaque, it will become challenging to see the retrograde catheter or the proximal end of the double J stent, so only a minimal amount of diluted contrast is used. The open-ended catheter has easily visible 1 cm markings, so the ureteral length (Uretero-Pelvic Junction to the ureteral orifice) is easily measured.

The proximal coiled end of the stent will always migrate to the most inferior position possible in the renal pelvis. This will extend the distal end of the double J further into the bladder where it may impact the opposite bladder wall causing additional patient discomfort. For this reason, if the ureteral length measures an odd number of centimeters, select a stent that matches the shorter length. There is sufficient length in the double J stent coils to easily stretch the extra centimeter without any harm, discomfort, or migration risk.

Choose a stent with the proper degree of rigidity.The stiffness or rigidity of the stent should be selected based on the clinical situation. More rigid stents are recommended in strictures, cancer cases, or when a stone cannot be dislodged and must be bypassed by the stent. The extra rigidity resists decreased drainage due to possible stent compression, better than a stent from a softer material.

Use the correct French size. The standard size for double J stents is typically 6 French. Larger diameter stents (larger French sizes) are recommended when draining infections in obstructive pyelonephritis and pyonephrosis or for dilating strictures. If a larger French size stent is desired but cannot be placed, consider using two smaller French-sized stents in tandem.

The proximal end of the stent should be fully coiled and in the most inferior possible position in the renal pelvis. The secret is to allow the proximal end of the double J stent to curl fully, then move it into position while still leaving the guidewire partially inside the distal portion of the stent. Tension on the dangler/safety thread keeps the stent, pusher, and guidewire connected as a unit which allows for manipulation and even complete stent removal/replacement while leaving the guidewire in place for ureteral access.

Getting the proximal end of the stent to curl in a small renal pelvis can be tricky. A maneuver called the "Leslie Flip" is often helpful in such situations. This involves retracting the guidewire slightly but just from the proximal end of the stent, then pulling the stent, wire, and pusher back into the proximal ureter followed immediately by slowly pushing all of them forward, back into the renal pelvis. The proximal stent tip, with its strong coiling memory, will try its best to make a fully circular coil now that it's no longer being straightened by the guidewire. Meanwhile, the rest of the stent is secure. This maneuver can be repeated if necessary, to obtain optimal results. (It is critical to have the dangler/safety thread in place and under mild traction to be able to do this maneuver. Otherwise, the stent may not retract. This is one of the reasons we recommend leaving the dangler/safety thread in place until the very end of the procedure.)

Do not cut the dangler/safety thread until the procedure is completed. As long as the dangler/safety thread is attached to the distal end of the stent, it holds the stent and the pusher together while the guidewire remains in place between them, keeping them connected and aligned. This essentially makes a single unit of these separate items which facilitates positioning and allows for the "Leslie Flip" maneuver described previously. Cutting the dangler/safety thread at the beginning of the case makes it almost impossible to change or even manipulate the stent without sacrificing the guidewire and possibly losing access. In such cases, it may be impossible to regain ureteral access, which can significantly complicate the patient's clinical course. This is the single most helpful tip in double J stent placement and the most commonly omitted.

The dangler/safety thread needs to be removed in a manner that will not move the stent out of position. The dangler thread can easily be cut and removed at the end of the case as long as the pusher is still in place and the guidewire is always at least partially inside the distal end of the double J stent. The partially inserted guidewire and pusher together stabilize the distal end of the stent and keeps everything properly aligned with only gentle traction on the dangler thread. Without the thread, there is no way to keep the stent from moving during manipulation or to extract it without losing the guidewire and possibly ureteral access as well. Once the thread is removed, the guidewire can be quickly and easily withdrawn without dislodging the stent since the pusher will prevent distal stent migration and inadvertent extraction.

Copyright © 2023, StatPearls Publishing LLC.