Evaluation Of A Dissolvable Ureteral Drainage Stent In A Swine Model:

Practice patterns of ureteral stenting after routine ureteroscopic stone surgery: a survey of practicing urologists

BACKGROUND

Controversy exists regarding the need for ureteral stent insertion after routine ureteroscopic stone surgery. We designed a questionnaire to assess and better understand the practice patterns of urologists for stent applications.

MATERIALS AND METHODS

A 26-question survey was distributed to 570 community and academic urologists. The answers were anonymously tabulated to determine the practice patterns for stent placement.

RESULTS

Of the 173 respondents, 97.7% performed ureteroscopic surgery, with the majority (77%) performing 1 to 10 procedures per month. Sixty-eight percent of urologists considered more than 70% of their ureteroscopic procedures "routine." Only 21% of urologists dilated the ureteral orifice more than 90% of the time. Those who dilated the ureteral orifice used a balloon (43%), ureteral access sheath (13.5%), or both (21%). The use of an access sheath did not change stenting practices for 75% of urologists. Patterns vary with regard to length of indwelling time, with 85% of urologists maintaining the stent for fewer than 7 days. Most urologists use either cystoscopy (42%) or pull-suture in clinic (37%) to remove stents. Patient tolerance is the most significant problem with stents reported by 97.6% of urologists. The respondents were divided into three experience-based groups: group 1, <2 years of experience; group 2, 2 to 10 years; and group 3, >10 years. Using Fisher's exact test, there were no statistically significant differences between the groups.

CONCLUSION

A wide variability exists among urologists in the practice patterns of stent insertion after routine ureteroscopic surgery. Most consider their procedures routine and are more likely to place stents after ureteral dilation despite growing evidence to the contrary. Knowledge of the varied practices may aid less experienced urologists in their decision to insert a stent after ureteroscopy.

Second Prize: Double-Blind Randomized Controlled Trial Assessing the Safety and Efficacy of Intravesical Agents for Ureteral Stent Symptoms after Extracorporeal Shockwave Lithotripsy

BACKGROUND AND PURPOSE

Ureteral stents are a significant source of pain and discomfort for many urologic patients. A novel approach to addressing this problem is the intravesical instillation of a selected pharmacologic agent after stent insertion. The purpose of this study was to assess the safety and efficacy of intravesical instillation of various agents in reducing ureteral stent-associated discomfort in patients requiring a stent after extracorporeal shockwave lithotripsy (SWL).

PATIENTS AND METHODS

In this double-blind prospective trial, 42 patients were randomized to receive intravesical instillation of one of three agents (oxybutynin, alkalinized lidocaine, or ketorolac) or a control solution (0.9% sodium chloride) immediately after stent insertion at time of SWL. The four groups of patients were demographically similar. Preoperative, intraoperative, and postoperative data were collected prospectively and analyzed statistically. The primary outcome measure was reduction in ureteral stent symptoms, and the secondary outcome measure was the safety of intravesical instillation of each agent through assessment of drug-related adverse events.

RESULTS

There were no intraoperative or postoperative complications, nor were there any serious side effects attributable to any of the intravesically instilled agents. There was a statistically significant decrease in stent-related discomfort at the 1-hour time point in the group of patients who received intravesical ketorolac compared with the control group.

CONCLUSIONS

Intravesical instillation represents a novel approach to the problem of ureteral stent-related discomfort. From our results, ketorolac appears to be the most effective intravesical agent in reducing stent-related patient discomfort, and we have established that intravesical instillation of ketorolac is safe in humans.

Advances in ureteral stent design

BACKGROUND AND PURPOSE

Ureteral stents are widely used in patients with urologic disorders. This review critically evaluates the recent literature, providing an update on advances in the development and design of stents.

METHODS

A thorough MEDLINE and PubMed literature search on ureteral stents was performed, and all pertinent articles were reviewed in detail. This review was formulated on the basis of these articles, encompassing both basic science and clinical aspects of advances in ureteral stent design.

RESULTS

The advances in development and design have been directed primarily toward decreasing stent-related morbidity such as discomfort, bladder irritability, infection, encrustation, and the need for an additional cystoscopic procedure to remove the stent. In recent years, there have been many significant advances in the design of ureteral stents, including tapered distal ends, and construction, such as magnetic, biodegradable, and tissue-engineered materials.

CONCLUSIONS

There are many different bulk materials and coatings available for the manufacturing of ureteral stents, many of which are new. However, the ideal biomaterial has yet to be discovered. With ongoing research in this area, further advances in ureteral stent design will continue to improve outcomes for patients who require stents. Future advances are likely to include drug-coated stents, drug-eluting stents, and localized stenting techniques such as endoluminal gel paving.

Phase I trial of a temporary ureteral drainage stent

BACKGROUND AND PURPOSE

The temporary ureteral drainage stent (TUDS; Boston Scientific/Microvasive, Natick, MA) is a biodegradable device that is designed to maintain patency for 48 hours with gradual softening and spontaneous expulsion thereafter. We evaluated the durability, patency, and safety of TUDS in a Phase I clinical trial.

PATIENTS AND METHODS

Eighteen stone patients requiring sequential percutaneous nephrolithotomies (PNL) for complex stone disease underwent antegrade TUDS placement following initial percutaneous treatment. Nineteen devices were placed in 21 attempts, with one patient undergoing bilateral TUDS placement. Day 2 nephrostograms were performed to allow assessment of stent status and to demonstrate antegrade flow. Stents were removed at the time of the secondary PNL (day 2 or 3).

RESULTS

No complications occurred during TUDS placement. On day 2, 1 stent had passed into the bladder. Eleven stents were completely intact, with seven others partially intact. Day 2 ureteral patency was demonstrated in all 19 stented ureters. Eighteen TUDS were removed completely during the secondary PNL with one incident of partial retention. All stent material had passed out of the body in all patients by 1 month. No adverse events were attributable to the TUDS.

CONCLUSIONS

The TUDS appears to facilitate ureteral drainage for at least 48 hours after placement. Although occasional stent tail detachments were noted, these did not interfere with device function. The safety profile of TUDS was favorable, with no complications attributable to the device itself. A larger prospective clinical study in patients receiving TUDS placed retrograde after uncomplicated ureteroscopic manipulation appears appropriate on the basis of these initial findings.