Dismembered pyeloplasty is the gold standard but there is no drainage gold standard.
There is agreement among pediatric urologists that a dismembered pyeloplasty is the best technique to repair a ureteropelvic junction obstruction. However, significant disagreement exists with regards to the drainage options after the pyeloplasty: ureteral stent vs. a perc tube vs. nothing at all.
If a ureteral stent is left in, there is the option of leaving a dangler attached to the end. Some have even considered placing a stent but just into the distal ureter, to avoid stent-related bladder problems.
Each of the different drainage options just mentioned can add surgical time or create the need for further procedures weeks after the pyeloplasty. Ultimately, all urologists want to do whatever will result in the best chance at a successful pyeloplasty –defined here as improvement of hydronephrosis with the resolution of symptoms — and the lowest chance of postoperative complications — leaks, obstruction, UTI’s, and unanticipated procedures.
Surgeon experience is insufficient to judge the best drainage option
The success of a laparoscopic pyeloplasty (assisted with the robot or not) is commonly quoted to be around 95% (90-100%). That means that on average, a surgeon should have 5 failures after doing 100 pyeloplasties. For most pediatric urologists, it will take a few years to reach 100 pyeloplasties and thus failures will likely come once or 2 times a year.
If the difference between leaving a stent or not, only marginally affects the outcome, most pediatric urologists won’t be able to tell the difference in their outcomes if they change their drainage option. If we hypothesize that stentless pyeloplasty results in a 10% failure rate and the stented one in a 5% failure rate, a study with 450 patients in each arm would be necessary to demonstrate the difference. If the failure rate is instead 6% and 3% respectively, the study will have to include 750 patients in each arm. Since randomized clinical trials this large are logistically unfeasible, urologists are left only with their “experience” to determine the best approach.
Are failures due to complications or due to insufficient removal of diseased ureter?
During residency, I trained with a pediatric urologist who did not leave a stent after pyeloplasties. His dissection was impeccable and the anastomosis was done with interrupted 7-0 PDS in a meticulous fashion. Before the last suture, he would test for leaks by placing an angiocath in between 2 sutures and filling the pelvis with saline. A more technical perfect procedure cannot be done in my opinion. Despite that, he frequently had to take patients back the next day to place a stent and his failure rate approached 10%. My conclusion was that his problems were due to not placing a stent. I have done about 100 robotic pyeloplasties myself and I had not had to bring anyone back to the OR yet. I have only had 2 failures that I am aware of. I have always left a stent for about 4 weeks and never have left a drain.
Before we dig deeper, I think something needs to be acknowledged. Most cases of UPJ are due to an intrinsic problem in the ureter affecting peristalsis. In a way, the problem is similar to Hirsprung’ss disease, where there is an aperistaltic segment in the distal colon causing the obstruction. When pediatric surgeons fix Hirsprung’ss disease, they make sure they remove all the aperistaltic segment by taking full-thickness biopsies and stopping until they get to the normal colon. Urologists on the other hand do not have an objective way of confirming whether the entire abnormal ureter was removed or not. A surgeon that tends to remove more ureter than others will thus likely tend to have fewer failures and vice-versa, independent of their stent or drain choices. The doctor I trained with could have been timid in his spatulation of the ureter and I probably have been more aggressive at it and that and only that could account for the difference in outcomes and complications, and have nothing to do with stents and drains.
Now let’s outline some pyeloplasty options with their advantages and disadvantages:
No retrograde at the beginning, ureteral stent placed antegrade during surgery.
- Saves the time it takes to position the patient for the retrograde and reposition for the procedure –around 30 minutes.
- Placing the stent is very straightforward in most cases only taking a few minutes.
- Requires a brief anesthetic later to remove the stent –1 minute procedure.
- When the stent is difficult to place in the antegrade fashion, cystoscopy has to be done in between the drapes which can be difficult.
Retrograde at the beginning with stent placement leaving dangler
- Avoids a second anesthetic
- The stent can be pulled inadvertently during the case or after the case because of the dangler
- Dangler can facilitate infection
- Adds 30 minutes or so to the case
- The stent can get in the way of the dissection and suturing –might take time getting used to it.
- The most efficient option
- Avoids a second anesthetic.
- Potential for more failures and postop complications?
- Avoids a second anesthetic
- Tube sticks out of the skin
- Takes time to place and can be technically difficult to do laparoscopically.
Here is a webinar discussing the above options: