Suprita Krishna, MD, MHA, was one of the recipients of the 2024 Urology Care Foundation™ Research Scholar Awards. These awards provide $40,000 annually for mentored research training for clinical and postdoctoral fellows or early-career faculty. The Endourological Society Joseph Segura, MD, Scholarship in Endourology and Stone Management sponsored Dr Krishna’s award.

Ureteroscopy is the most common procedure for patients with urinary stones in the United States.¹ Developments in endoscopic technology, lasers, and instrumentation have increased its availability and driven many advances in techniques over the last decade. One commonly used device is the ureteral access sheath (UAS).²

Why Use a UAS?

While surgical techniques for treating upper urinary tract stones with ureteroscopy may vary (ie, stone dusting vs fragmentation), many surgeons like using a UAS. In the state of Michigan, a UAS was used in 38% of all ureteroscopy procedures for urinary stones.² In a worldwide survey of endourologists, 58% used a UAS when treating renal stones with ureteroscopy.³ The UAS has been used as an adjunct to facilitate stone basketing from the kidney. Many surgeons like to use wider diameter UAS (eg, ≥12F/14F), as these permit larger fragment removal. It can also be used when a dusting technique is employed to allow higher irrigation, improve visualization, and mitigate intrarenal pressure rises by permitting passive drainage of irrigants.⁴

What Is the Problem?

Currently, it is routine practice to place a ureteral stent after using a UAS. This is partly due to the risk of ureteral trauma when using this device. In one study, the severe ureteral injury rate was 13.3% when a 12F/14F UAS was used.⁵ Although it is logical to stent in cases of ureteral injury, many patients who undergo UAS placement do not develop such injuries, raising the question of whether stenting is always necessary.

The practice of routine stenting after UAS use is based on 2 retrospective studies conducted in academic settings. Rapoport et al observed a comparable rate of emergency department (ED) visits following ureteroscopy in a study of 161 patients, regardless of whether they were stented or not. However, among 33 patients who underwent ureteroscopy using a 12F/14F UAS, 37% of nonstented vs 14% of stented patients returned to the ED.⁶ In a subsequent study, Torricelli and investigators studied stent omission vs placement after using a 12F/14F or 14F/16F UAS. Stented patients had lower pain scores on the first postoperative day, but there were no differences in infection or unplanned encounters, including ED visits.⁷ More recently, a small randomized controlled trial (RCT) comparing stent omission vs placement after using a 12F/14F UAS found no differences in pain scores on postoperative days 1 to 3 between groups. Patients who were not stented had no unplanned encounters, compared to 15% of the stented group.⁸

Why Should We Reduce Stenting After Ureteroscopy?

Ureteral stents play a crucial role in maintaining urine flow and preventing complications such as pain from trauma or obstructing fragments. However, multiple studies have shown that stents are associated with significant morbidity. Per the AUA guidelines, stents may be omitted in patients undergoing uncomplicated ureteroscopy for stones (≤1.5 cm), provided there is no evidence of ureteral injury or anatomical abnormalities.⁹

What Are the Gaps in Existing Data?

While UASs are routinely utilized, no RCTs evaluate the need for postprocedural stenting, which adds a significant burden to patients and urologists. Limitations of current studies include the following:

1. Lack of robust level 1 evidence
2. Bias in patient selection from academic centers
3. No evaluation in the dusting era
4. No objective criteria to assess stent placement: the decision to place a stent was based on a subjective evaluation of the ureter as opposed to a validated scale such as the Postureteroscopic Lesion Scale¹⁰
5. Using only large-size UAS (eg, 12F/14F, 14F/16F)
6. No assessment of patient-reported outcomes (PROs)
7. Lack of standardized health care outcomes

What Is Our Study Proposal?

With the development of smaller UAS, which carry a lower risk for trauma, changes in the design of UAS, and improvements in laser technology where stones can be effectively dusted, the omission of stents after using a UAS could be considered. Our hypothesis is that stent omission vs placement after uncomplicated ureteroscopy and lithotripsy using a 10F/12F UAS will be associated with no differences in PROs and 30-day health care utilization.

What Are Our Preliminary Data?

From the MUSIC (Michigan Urological Surgery Improvement Collaborative) registry, we identified a subgroup of patients who underwent uncomplicated ureteroscopy with a UAS. Post ureteroscopy, 361 patients were stented, while stent was omitted in 29 patients who had been prestented. Patients’ median pain intensity and interference were similar in stented vs nonstented groups. When stratified by stone location, patients with ureteral stones without stent placement had slightly higher PROMIS Pain Intensity scores at 7 to 10 days (56.7 vs 54.8), but Pain Interference was the same in both groups (58.1). When we assessed 30-day ED visits, patients who were not stented (n = 29) had no ED visits (0%) compared to 22 ED visits (6%) in the stented group.

What Is Our Study Design?

The Access Sheath and Stent (ACCENT) clinical trial is a single-blinded, multicenter, pragmatic RCT comparing PROs related to stent omission vs placement after uncomplicated ureteroscopy using 10F/12F UAS (Aim 1), as well as 30-day health care utilization (Aim 2). The primary outcome is the difference in PROMIS Pain Interference scores 7 to 10 days after ureteroscopy. Patients with stones ≤ 1.5 cm on preoperative assessment and Postureteroscopic Lesion Scale 0 or 1 on intraoperative ureteral assessment will be randomized to stent omission vs placement (Box).

Box. Inclusion and Exclusion Criteria of the Access Sheath and Stent (ACCESS) Trial

Abbreviations: PULS, Postureteroscopic Lesion Scale; UAS, ureteral access sheath; URS, ureteroscopy.

Eligible patients will have their baseline and postprocedure PRO surveys, unplanned health care encounters (≤30 days), and postoperative imaging results and stone-free rates (≤60 days) recorded (Figure).

What Do We Hope to Achieve?

Unlike prior work, which is limited to academic medical centers, the patients will come from a diverse group of hospitals from a quality collaborative (MUSIC) representative of real-world practice. Our goal is to provide data that will enhance the ability of urologists to counsel patients on stent placement vs omission after an uncomplicated ureteroscopy using a UAS. This project will support our efforts to advance urological care and develop personalized treatment strategies tailored to individual patient needs.