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 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 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 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 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 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.
Double J stents have been used for more than 25 years and have become a staple of the urological endoscopic armamentarium. They are primarily used for stabilization of the ureter after surgery and to provide drainage through a ureter that may be obstructed, leaking, dysfunctional, or strictured. They are often used after extracorporeal shockwave stone surgery to minimize blockage from steinestrasse (multiple stone fragments that can clog and obstruct a ureter after lithotripsy), to bypass a larger immovable ureteral calculus or to help identify the ureter radiologically or surgically.
Stents are also used as gentle ureteral dilators. If a tortuous, narrowed, or strictured ureter is encountered during ureteroscopy, placement of a double J stent will gradually dilate the lumen allowing for much easier ureteroscopy at a later date.
Or as one of the early pioneers in endourology, Dr. Arthur Smith, famously said, "When the going gets tough, the tough leave a stent and go home!"
Having a wide variety of stent diameters and lengths is optimal. It is preferable to have both soft double J stents and rigid ones, but if you have to choose only one, pick the rigid type but insist on the largest possible selection of widths and lengths. The most commonly used size is a 6 French, 26 cm stent. Some very large patients will need longer stents and some patients with a horseshoe, or pelvic kidney will require very short ones.
Getting the guide wire or the open-ended catheter into the distal ureter can sometimes be difficult. Start by using the right size cystoscope sheath. Too small a sheath will not allow a 7 or 8 French stent, but if the cystoscope is too large, it will be difficult to secure and direct the open-ended ureteral catheter, stent and guide wire. Consider using an Albarran deflecting bridge which allows for a little adjustable deflection at the tip of the cystoscope. This will permit approaching the ureteral orifice at a more acute angle which will often work much better. The Albarran bridge will also provide additional intravesical stabilization of guide wires, ureteral catheters, and stents. Our personal preference is to use an Albarran bridge with a 70-degree lens and a 19 to 22 French cystoscope sheath for double J stent placement.
Be careful when advancing an open-ended catheter up the ureter without a guide wire. The edges of the catheter can be sharp enough to cause significant and unnecessary bleeding if pushed or forced up the ureter even with a guide wire. Some open-ended ureteral catheters have a slightly tapered tip, and these are preferable as they will tend to cause less ureteral trauma and reduce bleeding.
Ureteral balloon or solid dilators may occasionally be necessary and should be readily available. If a specific strictured area is identified on retrograde pyelography or fluoroscopy, it is helpful to place a marker (such as a sticky note or a signature request tab) directly on the fluoro screen to identify its exact location. This is particularly helpful for balloon dilation. If such dilation is not successful for any reason, it may be preferable just to leave a stent for passive dilation and return another day to complete the procedure.
Guide wires are a matter of personal taste. Hydrophilic wires are generally preferred but need to be kept moist for optimal performance. For this purpose, we always keep a wet sponge on the field to quickly moisten the wire and the stent. Always wipe from the outside (distal) end towards the urethra (proximal) end to avoid inadvertent dislodgement of the stent or guide wire.
Placing a double J stent is a 2 person job so make sure to have an assistant who is able and willing to help. It can be very frustrating when the clinician is in the middle of a case and the only available assistant cannot or will not assist.
After trying innumerable variations, we have developed a technique that maximizes reliable double J stent placement while allowing for easy reversibility and guaranteed ureteral access. It also facilitates optimal stent positioning and renal pelvis stent coiling to minimize migration and patient discomfort.
Determine the Optimal Stent Length
Measure the ureteral length from the urinary meatus to the ureteropelvic junction (UPJ) either by a retrograde pyelogram (then subtract 10% due to radiologic magnification) or (preferred) determined directly with a marked ureteral catheter. This is done by placing the catheter tip at the UPJ and then cystoscopically checking the markings at the ureteral meatus. A small amount of diluted contrast can be injected through the ureteral catheter to help identify the UPJ. Double J stents only come in even lengths, so if the ureteral length measurement is an odd number of centimeters, choose the double J length that is 1 cm shorter. Note that the stent length does not include the curls at either end. As a general rule, the average ureter takes a 26 cm length stent.
Select the Optimal Stent Diameter and Stiffness
After establishing the ureteral length, the next issue is a decision on the width and rigidity (compressibility) of the stent. Softer stents may be more comfortable for the patient, but stiffer ones are likely to be more reliable and crush resistant. With larger stones and tighter spaces, go with a firmer material and a smaller diameter stent. Also, use a firmer catheter material when dealing with tortuous ureters and malignancies. For ureteral strictures or severely infected kidneys, use larger diameter stents. Consider a metallic stent for malignancy or if the stent will be required permanently.
Guide Wire Placement (Routine)
With the double J stent selected, the next step is placing the guide wire. The guide wire can be inserted directly into the ureteral orifice, or it can be placed through a 5 or 6 French open-ended ureteral catheter. It should be advanced until the floppy tip coils in the renal pelvis as determined fluoroscopically.
Guide Wire Placement (Difficult)
Guidewire placement is not usually a problem, but it can sometimes be challenging; especially when dealing with impacted stones, strictures, cancers, and tortuous ureters. First, try a different wire. We typically start with a hydrophilic stiff shaft straight tip but recommend an angled tip wire in difficult situations. The stiffer shaft wire helps straighten tortuous ureters, and it seems to be easier to advance with less bowing. In some cases, we may pass two wires to help straighten an unusually tortuous ureter. This can be easily done with a dual lumen ureteral catheter.
When the guide wire does not advance easily, use a 5 French open-ended catheter to provide stability and prevent bowing of the wire. Place the open-ended catheter within 1 cm of the obstruction and then gently try advancing the wire through the catheter while twisting the wire slightly right and left. Use fluoroscopy for guidance and a torque vise or similar device to better handle, twist and advance the guide wire.
The obstruction only has to be successfully traversed once to provide proximal access. If the only partial passage is achieved, advance the open-ended catheter gently and carefully over the guide wire as much as possible, and then repeat the guide wire advancement technique described above. For even greater stability and support, a dual lumen catheter can be substituted for the standard open-ended catheter.
A combination of lidocaine jelly and contrast can be very useful in these situations. Inject a small amount through the open-ended catheter to help with visualization and reduce ureteral spasm. Use of a smaller syringe (3 or 5 mL) is recommended for this retrograde injection due to the high viscosity of the mixture.
Use Retrograde Pyelography
With the guide wire in place, advance the open-ended catheter to the UPJ and measure the ureteral length. The guide wire can be safely removed to do a retrograde as long as the tip of the open-ended catheter is beyond any stricture or blockage. A few milliliters of diluted contrast can be injected to help identify the UPJ. After measuring the ureteral length, replace the guide wire and remove the ureteral catheter. If the ureter is particularly tortuous, consider using a second guide wire to help straighten it. If the ureter is significantly narrowed or tight, ureteral dilation with either a Nottingham dilator, tapered ureteral catheter or balloon dilator may be needed. In these situations, consider using a smaller diameter double J stent immediately, then replacing it with a wider one later after a reasonable period of passive dilation from the original stent.
We like to position the fluoroscope so that the center of the renal pelvis is in the exact middle of the radiologic viewing field so that even if the injected contrast has dissipated or drained away, there is still an indicator for the precise location of the center of the renal pelvis.
Keep the Guide Wire Moist
Start at the most distal end of the guide wire and wipe just the tip with a wet sponge from proximal to distal. This avoids having the guide wire accidentally perforate the sponge and getting caught. Then wipe the rest of the guide wire from distal to proximal to avoid accidental extraction or movement of the guide wire. We keep a wet sponge handy on the patient’s knee and another on the side of the water basin to help keep these hydrophilic supplies moist and wet whenever they are used or manipulated.
Load the Stent
Loading the proximal end of the double J stent, the end without the safety thread, over the distal tip of the guide wire can sometimes be tricky. Use the supplied plastic outer sheath, if available, as an aid to straighten out the curve of the stent. Adjust the plastic sheath so that the proximal tip of the stent is just inside the sheath, about 1 cm from the tip.
Make sure the double J and guide wire are both very moist if using hydrophilic materials; otherwise, it can be very difficult to advance the stent over the guide wire. Most hydrophilic guide wires and stents dry out very quickly and then become sticky.
Advance the guide wire into the stent. Place one hand on the distal end of the plastic outer sheath and pinch the stent and plastic sheath together. This extra stability facilitates passage of the guide wire through the stent as otherwise, the guide wire may just push the stent out the back of the plastic sheath. Once the guide wire is through the proximal coiled end of the stent, slide the sheath outwards to straighten out the distal coil and push the guide wire all the way through. Remove the plastic outer sheath once the guidewire has passed through the entire stent and is visible at the distal end. Do not remove the thread yet.
Place the Double J Stent
Push the stent into the cystoscope until you can see the proximal end of the stent enter the distal ureter. Then have the pusher placed over the guide wire and use it to slide the stent over the guide wire into the ureter and up into the renal pelvis. Now pull the guide wire back slightly so that the tip of the wire is just below the curl of the proximal end of the stent. Hold the pusher, guide wire and the safety thread from the stent together as a single unit and gently move it a few centimeters in and out of the ureter as previously described. This will allow the soft, proximal end of the stent to curl up in the renal pelvis naturally. By holding the stent, pusher, and thread together, the entire process can be easily reversed just by pushing the guide wire back into the renal pelvis allowing for stent repositioning or even complete removal while leaving the guide wire in place for ureteral access.
Remove the Dangler/Safety Thread
When completely satisfied with the proximal renal curl of the stent and its distal (bladder) placement, with the black mark from the stent visible at the ureteral orifice, cut one end of the dangler/safety thread close to the cystoscope nipple and completely remove the thread. Make sure the knot is distal to the point where the thread is cut. Removal of the thread with the guide wire and pusher still in place stabilizes the double J and minimizes the chances of inadvertently moving or extracting the stent. The thread can optionally be left in place and secured at the end of the case to the inner thigh or dorsum of the penis. This is recommended only when the expected need for the stent is one week or less as it is prone to accidental early dislodgement or removal by the patient. Do Not Remove the Dangler/Safety Thread Until Completely Satisfied With the Proximal Stent Tip Coiling in the Renal Pelvis as Well as the Distal Stent Position!
Guide Wire Removal
Immediately after the thread is removed, pull the guide wire completely out. (Up to this point, the guide wire has been in place just below the proximal coiled stent tip, stabilizing the position of the stent, so it does not move or get pulled out accidentally.) To safely remove the pusher, first advance the pusher in a few centimeters until the distal stent tip has been pushed out of the cystoscope sheath and the end of the stent is visible completely inside the bladder. Now it is safe to remove the pusher. If the coiling is not optimal in the bladder, a biopsy forceps or grasper can be used to adjust it through the cystoscope.
Review the final position of the double J stent fluoroscopically and cystoscopically to ensure optimal placement and positioning. Finally, empty the bladder and remove the cystoscope.
Change or Remove the Stent Appropriately
Double J stents will tend to develop stone material on their surfaces, particularly in the renal pelvis and the bladder which can make standard cystoscopic stent removal extremely difficult or even impossible. For this reason, stents typically need to be changed regularly or removed. It is the surgeon's responsibility to keep track of the stents and make sure his patients do not fail to have them changed or removed at the appropriate time. In pregnancy, changing stents every 4 to 6 weeks is recommended due to rapid encrustation. Most standard stents can remain for 3 to 6 months but this time will vary according to the patient's urinary chemistry and stone producing propensity. Every commercially available stent will have a maximum recommended indwelling time which should be followed.
Side Effects from Double J Stents
Stent discomfort can be minimized with alpha blockers like tamsulosin and alfuzosin. Bladder irritability (frequency and urgency) can be treated with anticholinergic medications as needed. Several studies have suggested a benefit from the combined use of tamsulosin and solifenacin.
Stents will need to be changed more often in pregnant ladies than in other patients, even those with previous nephrolithiasis. Consider a percutaneous nephrostomy as an alternative.
Some degree of hematuria is not uncommon with stents; especially in patients on anticoagulants. This is typically only an issue if the hematuria is excessive. It is important to inform patients that they may have hematuria with stents to avoid undue anxiety.
Remember that once a double J stent has been placed, it is the responsibility of the surgeon to make sure that it is removed appropriately and at the right time. When stents are inadvertently left in place for months, or even years longer than intended, they inevitably become calcified and may also move or migrate out of position. It is the surgeon's responsibility to make sure the stent is removed in a timely fashion and not forgotten.
The primary major complications of double J stents are almost always associated with leaving the stent indwelling too long which causes stent migration, encrustation, stone formation and fragmentation of the stent. Urinary tract infections, renal failure and the very rare fistula formation to the iliac vessels have also been reported.
Stent migration is most likely to occur in a patient who is long overdue for stent removal or replacement. The stent can end up completely within the renal pelvis or the bladder. A lesser degree of migration can be due to selecting a stent that is much too short. In this case, the distal end of the stent, the portion that is normally in the bladder, will migrate up the ureter and not be visible on cystoscopy. These will need to be removed with ureteroscopy.
Stents that make full coiled circles at either end when placed are less likely to migrate than those with only partial coiling.
Stones and stent encrustation will occur in any stent left in the urinary system long enough. Risk factors include lengthy indwelling stent time (3 months or more), chronic renal failure, pregnancy, history of previous nephrolithiasis, chemotherapy and pre-existing metabolic or anatomical abnormalities. Standard extracorporeal shockwave lithotripsy (ESWL) is frequently used for this problem; it works best on lower volume stent encrustation and stone disease.
Stents are manufactured with very strong materials. However, they can sometimes fracture and fragment into pieces. While this is usually associated with prolonged indwelling time, it can happen much quicker. The fracture points are almost always at the sites of the stent drainage holes. Fortunately, this complication is quite rare.
The best treatment for these complications is prevention which is why it is so important to avoid prolonged stent indwelling time. As stated earlier, most stents should be changed optimally at 3-month intervals and certainly by six months. In pregnancy, we recommend stent changes even more frequently: every 4 to 6 weeks due to the accelerated encrustation that occurs.
Treatment of existing complications usually involves ureteroscopy and/or percutaneous endourological procedures and is almost always successful.
Three months is the usual recommended maximal indwelling stent time, but six months should be the absolute maximum limit. Patients with stents that are lost to follow-up or "forgotten" are much more likely to encounter these complications.
Rarely, complications from "forgotten" double J stents can be serious, and several deaths have been reported.
Use of double J stents in urology is now standard practice, yet the optimal technique for their placement has not been described previously. After a careful analysis, the technique, mentioned earlier, that includes exact ureteral length measurements for ideal stent length selection, use of the dangler/safety thread to help manipulate the stent into optimal position, and partial extraction of the guide wire to promote proximal stent tip coiling while maintaining total control of the stent, guide wire, and pusher, is recommended. This technique optimizes patient safety and comfort and facilitates easy stent replacement, if needed, without losing ureteral access.
Use of double J stents has revolutionized endoscopic urological practice and is now an integral part of urology. Use of the optimized placement technique described and improved stent selection will minimize patient discomfort, side effects, and complications while retaining access for maximal patient safety and comfort.