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 previously reported. The ideal double J placement technique would be totally reversible, include an accurate and reliable ureteral measurement for optimal stent length selection, and would guarantee ureteral guide wire 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 common stent side effects and complications, etc.Features of an Optimal Double J Stent Placement Technique: Basic PrinciplesUse 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 give 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 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 guide wire. 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 difficult 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 softer material.Use the correct French size. The standard size for double J stents is typically 6 French. Larger diameter stents (higher French sizes) are recommended when draining infections in obstructive pyelonephritis and pyonephrosis. If a larger French size stent is desired but cannot be placed, consider using two smaller French sized stents.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 guide wire partially inside the stent. This allows for a possible reversal, manipulation and even complete stent removal/replacement while leaving the guide wire in place for ureteral access. Getting the proximal tip of the stent to curl in a small renal pelvis can be tricky. A maneuver called the "Leslie Flip" might be helpful in such situations. This involves retracting the guidewire 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 stent, with its strong coiling memory, will try its best to make a full circular coil. This maneuver can be repeated if necessary to obtain optimal results. (It is critical to have the dangler/safety thread in place to be able to do this maneuver. Otherwise, the stent may not retract. This is one of the reasons it is recommended to leave 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 pushes the stent and the pusher together while the guide wire remains in place between them, keeping them 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 guide wire and possibly losing access. In such cases, it may be impossible to regain ureteral access which can greatly complicate the patient's clinical course.The dangler/safety thread needs to be removed in a manner that will not move the stent out of position. The thread can easily be cut and removed at the end of the case as long as the pusher is still in place and the guide wire is still at least partially inside the double J stent. The partially inserted guide wire and pusher together stabilize the distal end of the stent and keeps everything properly aligned. Without the thread, there is no way to keep the stent from moving during manipulation or to extract it without losing the guide wire and possibly ureteral access as well. Once the thread is removed, the guide wire can be easily removed without dislodging the stent since the pusher will prevent distal migration of the stent and inadvertent extraction.
Sections
- Introduction
- Indications
- Equipment
- Personnel
- Technique
- Complications
- Clinical Significance
- Questions
- References
0000 [Epub]
Stephen W. Leslie, Patrick J. Shenot
Creighton University Medical Center, Thomas Jefferson University Hospital