for people ages 18 years and up (full criteria)
Healthy Volunteers
healthy people welcome
at San Francisco, California
study started
completion around
Principal Investigator
by Thomas Chi, MD
Headshot of Thomas Chi
Thomas Chi



A prospective, non-blinded, randomized controlled trial studying the management of symptomatic ureteral stones. This study will compare upfront ureteroscopy vs observation and delayed intervention for patients presenting to the emergency department with a symptomatic ureteral stone.

Official Title

Upfront vs Postponed Ureteroscopy (UPURS) Trial for Patient-centered Management of Symptomatic Obstructing Stones


Management of symptomatic ureteral stones is variable across the United States due to a lack of clear, patient-centered guidelines. For patients who do not meet criteria for emergent stenting, the decision to recommend upfront definitive treatment (ureteroscopy, ESWL) or medical expulsion therapy is influenced by factors such as practice setting, insurance status, and day of the week. This has resulted in health disparities and delays in care that disproportionately affect vulnerable patient populations.

For patients presenting to the emergency department with a symptomatic ureteral stone investigators will randomize into Group A: Upfront Ureteroscopy or Group B: Delayed intervention and observation. Both arms are considered standard of care for patients presenting with the above diagnosis.


Ureteral Stone, Symptomatic ureteral stones, Ureteral Calculi, Ureterolithiasis, Ureteroscopy, Upfront ureteroscopy


You can join if…

Open to people ages 18 years and up

  • Presenting to the Emergency Department (ED)
  • Adult (> 18 yo)
  • ≥5mm ureteral stone diagnosed on CT scan
  • Presence of symptoms (pain, nausea, vomiting, hematuria)

You CAN'T join if...

  • Strict indication for stent
  • Stone burden not amenable to Ureteroscopy (URS)
  • Dirty urine analysis (UA) or positive urine culture (UCx)
  • Transplant kidney
  • Presence of conduit
  • Comorbidities not optimized for surgery
  • Strong preference for surgery or observation


  • UCSF accepting new patients
    San Francisco California 94143 United States

Lead Scientist at UCSF

  • Thomas Chi, MD
    Professor, Urology, School of Medicine. Authored (or co-authored) 140 research publications. Research interests: Nephrolithiasis · Benign Prostatic Hypertrophy (BPH) · Ultrasound · Minimally Invasive Surgery · Laparoscopy


accepting new patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Expecting 100 study participants
Last Updated