There are already many established protocols and guidelines regarding ureteral stent insertion. Dr. Oliver Wiseman began the discussion by talking about the specific patient selection for ureteral stenting. He spoke on the effects that stents have on different patients and patient groups. Breaking down his talk into patient selection for pre-ureteroscopy, post-ureteroscopy, and peri-ESWL patients, he dove into the various risk factors that the respective patient populations face.
When surgeons plan to do ureteroscopy (URS) many times the surgeon cannot access the ureter. He presented data from the UK that looked at over 1,300 patients and showed that sometimes surgeons are forced to put a stent in prior to ureteroscopy. The mean rate was 7.5% in men and 4.1% for women.
For pre-ureteroscopy stenting, risk factors for postoperative sepsis were sepsis prior to ureteroscopy, median indwell time of the stent and female gender. To be sure, Dr. Wiseman emphasized that if a patient was stented for more than 4 weeks prior to URS, the sepsis rate increased significantly.
Regarding stent placement post-ureteroscopy, he refers to guidelines set that say that it is often appropriate to omit postoperative stenting as long as they met certain criteria outlined in the EAU guidelines. He also emphasized that many surgeons utilize post-URS stents simply for the fact of avoiding any stressful emergencies. He did acknowledge that they are not necessary as he referenced a meta-analysis of 16 randomized controlled trials, that showed no difference between patients who have stents and those who do not have stents in post-URS from the point of urinary tract infections, need for analgesia, and unplanned readmissions.
Which patients do urologists put stents in post-URS? According to Dr. Wiseman, these are the patients who have ureteral stones treated, if have had intraoperative complications, impacted stones, long operative times, increased stone burden, older age, or the presence of a solitary kidney.
If a surgeon does not put a stent in, where are patients most likely to present with morbidity? Dr. Wiseman said, “[these often occur when] [surgeons] do bilateral unstented procedures, lithotripsy for stone as part of the procedure, or if operative time is longer than 45 minutes.” These patients are more likely to have complications postoperatively.
Regarding peri-ESWL, the recommendation based on the talk was basically they should not be undertaken and this is known from the guidelines. Dr. Wiseman’s take-home messages were that: 1) surgeons should not be routinely stenting pre-URS as it leads to increased morbidity and cost and increases the risk of sepsis of subsequent URS. Due to the abnormally high rates of inability to access ureters especially in young men (Figure 1.), this may necessitate pre-URS stenting but the stent should be removed prior to 4 weeks as sepsis rates increase considerably. 2) Surgeons should not routinely place stent post-URS but should consider them if they have longer operative time (>45 min), URS with conjunction with lithotripsy and bilateral, or history of recent infection.
Next up to speak was Dr. Lange who spoke on the different types of stent designs. He began with saying that not much has changed to the current, most widely used double J stent in recent times, even acknowledging the existing complications such as infection, encrustation, and patient pain and discomfort.
He advocated for a “paradigm shift in stent design away from the double J stent” was needed. He began by talking about cancer stents that have a segmental configuration that sits only in part of the ureter. He spoke on the allium stent, Memokath stent, Uventa stent. He emphasized that all of these stents occupy less space in the ureter and fewer complications. He also remarked on various biodegradable stents which is an entirely different stent material. He completed his portion of the panel with the following conclusions below:
The last speaker of the panel was Dr. Jodi Antonelli who spoke on various medications implicated in stenting. She began by stating that “[u]reteral stent discomfort is a major issue for patients, [and] [m]any different drugs have been tried to mitigate patient discomfort.”
She was very thorough in going through the pharmacokinetics of the different drug classes and presented various studies associated with each drug. She spoke on alpha blockers, antimuscarinics, bladder analgesics, NSAID, pregabalin – she decided to omit her section on narcotics for this particular presentation. Starting with alpha blockers, she gave some background on alpha receptors in distal ureter and trigone. She then dove straight into several RCT and meta-analysis that have been done on alpha blockers. Explaining that most of the studies were heterogeneous, she still concluded that alpha blockers improved all symptoms scores and decreased pain index scores, improved general health scores, improved sexual and QOL scores. Alfuzosin seemed to be better than tamsulosin.
Regarding antimuscarinics, she said the primary mechanism is bladder relaxation and that they are overall safe and efficacious drugs. An interesting study she brought up was one that compared antimuscarinic vs. alpha blocker vs. placebo study. (Figure below) Alpha blockers alone and antimuscarinics alone had better outcomes than placebo as assumed. But, when the researchers did head to head comparison, antimuscarinics were advantageous in all domains except sexual function. She re-emphasized that data with alpha blockers and antimuscarinics are fairly heterogeneous. Referring to the AUA guidelines, surgeons can go ahead and offer both alpha blockers and antimuscarinics to reduce stent discomfort (similar to EAU guidelines).
Some other less studied drugs she talked about were bladder analgesics, NSAID, and pregabalin. The bladder analgesic that she focused on was phenazopyridine. She discussed a small study with 60 patients. This study showed no significant advantage with pain or urinary symptoms. Because of the small size of the study, it will be necessary to conduct larger studies to evaluate the true efficacy of the drug. NSAIDs, cox inhibitors that act as analgesics, were also discussed. The study that she introduced was a prospective study that utilized a single dose of placebo vs. NSAID right before stent removal. When evaluating severe pain within the 1st 24 hours, it was less with NSAIDs. To be sure, use of additional pain medication was less with the NSAID group as well. One study investigated antimuscarinics and pregabalin and found that the total urinary stent symptom questionnaire (USSQ) improved with combo therapy. Dr. Antontelli concluded that many medications exist for ureteral stent discomfort but are unable to adequately control stent-related symptoms for many patients. Currently, the greatest evidence is for antimuscarinics or alpha blockers because other classes have limited data at this point. She pointed out that there may be advantages for multimodal therapies.
Presented by: Drs. Ravi Kulkarni, MS, FRCS, Consultant Urological Surgeon, St. Peter's Hospital
Co-Authors: Oliver Wiseman, Jodi Antonelli, Dirk Lange
Author-Affiliation: St. Peter’s Hospital, Cambridge University Hospitals, UT Southwestern, University of British Columbia
Written by: John Sung, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France