Patient Positioning for Treatment of Proximal Ureteral Stones

Optimal Patient Positioning and Strategy for the Treatment of Proximal Ureteral Stones

Ureteroscopic management of proximal ureteral stones presents technical challenges including stone retropulsion, prolonged operative time, and conversion to intrarenal treatment. Reverse Trendelenburg positioning has been shown to reduce proximal stone migration and operative time in ureteral stones, while the T-tilt position improves intrarenal stone clearance. The optimal strategy for proximal ureteral stones (treating stones in situ using reverse Trendelenburg versus pushing stones into the kidney followed by intrarenal treatment in T-tilt) remains unknown.

This randomized controlled trial compares these two strategies, with primary focus on operative time as a measure of procedural efficiency.

A total of 54 patients (27 per arm) will be enrolled at Mount Sinai West.

Study Overview

• Status: Recruiting
• Conditions: Ureteral Stone
• Intervention / Treatment: Procedure: Reverse Trendelenburg Position; Procedure: T-Tilt Position

Detailed Description

Ureteroscopy has become a primary modality for the management of ureteral and renal calculi due to its high efficacy, minimally invasive nature, and favorable safety profile. Despite advances in flexible ureteroscopy, laser lithotripsy, and access technologies, proximal ureteral stones remain technically challenging, largely due to their tendency to migrate retrograde into the kidney, leading to prolonged operative time, increased need for flexible ureteroscopy, and lower procedural efficiency.

Stone retropulsion is influenced by laser energy, irrigation flow, ureteral anatomy, and gravitational forces. Several mechanical and laser-based strategies have been explored to mitigate migration, though results have been variable. Patient positioning represents a simple and cost-neutral intervention that may alter stone behavior intraoperatively without requiring additional devices.

Reverse Trendelenburg positioning has recently been shown to reduce proximal stone migration and improve operative efficiency during ureteroscopic treatment of ureteral stones. In a randomized controlled trial, patients positioned in reverse Trendelenburg experienced lower rates of retropulsion, reduced need for conversion to flexible ureteroscopy, and shorter operative times compared with standard positioning. However, this study included stones across multiple ureteral segments and did not focus specifically on proximal ureteral stones, which may have distinct anatomical and migration characteristics.

Conversely, T-tilt positioning has been investigated in the context of intrarenal stone treatment. Prior randomized evidence demonstrated that T-tilt positioning during retrograde intrarenal surgery resulted in higher stone-free rates, likely due to improved gravitational alignment of calyces and enhanced fragment clearance. These findings suggest that positioning may also optimize intrarenal lithotripsy efficiency once stones migrate into the kidney.

For proximal ureteral stones, two competing operative strategies are commonly used in clinical practice: (1) in situ ureteral treatment with efforts to prevent migration, potentially optimized by reverse Trendelenburg positioning, or (2) intentional pushback of the stone into the kidney followed by intrarenal lithotripsy under positioning conditions favorable for fragment clearance, such as T-tilt.

The decision to use one strategy over another is based on surgeon preference. Currently, there are no guidelines or standards favoring either approach. To date, no randomized study has directly compared these two positioning-based strategies for proximal ureteral stones. Given that operative time is strongly associated with anesthesia exposure, procedural cost, complication risk, and resource utilization, it represents a clinically meaningful and objective primary endpoint to evaluate procedural efficiency between approaches.

This study seeks to address an important gap in endourologic practice by determining the optimal positioning strategy for proximal ureteral stone management, with the goal of improving operative efficiency, reducing procedural burden, and informing evidence-based surgical decision-making.

• Study Type: Interventional
• Enrollment (Estimated): 54
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mantu Gupta, MD; Phone Number: 212-241-1272; Email: Mantu.gupta@mountsinai.org
• Study Contact Backup: Name: Blair Gallante, MPH; Phone Number: 212-241-1272; Email: blair.gallante@mountsinai.org

Study Locations

• United States
  • New York
    • New York, New York, United States, 10019
      • Recruiting
      • Mount Sinai West
      • Principal Investigator: Mantu Gupta, MD
      • Contact: Mantu Gupta, MD; Phone Number: 212-241-1272; Email: Mantu.gupta@mountsinai.org
      • Contact: Blair Gallante, MPH; Phone Number: 212-241-1272; Email: blair.gallante@mountsinai.org

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion criteria:

• Adults aged 18 years and older.
• Diagnosed with kidney stones and scheduled for fURS.
• Stone burden > 1 cm and/or multiple stones will be eligible.
• Able and willing to provide informed consent.

Exclusion criteria:

• Pregnant persons as determined by pre-operative urine pregnancy test (standard of care at the institution)
• Untreated UTI
• Patients with urinary anomalies (e.g., urinary diversion, ureteral reconstruction, horseshoe kidney)
• Single stone < 1 cm

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Reverse Trendelenburg Position; Participants undergo ureteroscopic lithotripsy in reverse Trendelenburg positioning with attempted in situ treatment of the proximal ureteral stone to minimize proximal migration.	Procedure: Reverse Trendelenburg Position; Patients will be positioned in reverse Trendelenburg at a 20 degree incline with the use of a digital protractor. Lithotripsy will be performed within the ureter with attempts to prevent proximal migration and until all fragments are removed.
Active Comparator: T-Tilt Position; Participants undergo intentional relocation of the proximal ureteral stone into the kidney followed by intrarenal lithotripsy performed in the T-tilt position.	Procedure: T-Tilt Position; Stone will be intentionally relocated into the kidney when feasible, followed by intrarenal lithotripsy in T-tilt position. In the T-tilt position the table is angled 15-degree Trendelenburg and 15-degree airplane away from the surgical side kidney with the use of a digital protractor. This allows fragments to rest in a superior and medial position away from the lower pole to facilitate removal.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total operative time	Operative time will be used to compare procedural efficiency	Immediately postoperatively on the day of surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of participants stone-free	Proportion of participants without residual stone fragments on postoperative CT imaging	From Week 4 to Week 6 postoperatively
Proportion of procedures requiring additional equipment or procedural maneuvers	Proportion of procedures requiring additional equipment or procedural maneuvers beyond the initially planned operative strategy to complete stone treatment	Immediately after completion of surgery on the day of procedure
Proportion of strategy failure	Proportion of cases in which the randomized operative strategy could not be successfully executed intraoperatively	Assessed immediately at completion of surgery on the day of procedure
Incidence of Complications	Incidence of postoperative complications, defined as any Clavien-Dindo complications, emergency department visits, or readmission related to the procedure. Outcome is recorded as the occurrence of a complication event (yes or no). Each participant is counted once, and the outcome is recorded as a binary variable indicating whether any of these events occurred or did not occur.	Through postoperative day 30

Collaborators and Investigators

• Sponsor: Icahn School of Medicine at Mount Sinai
• Investigators: Principal Investigator: Mantu Gupta, MD, Icahn School of Medicine at Mount Sinai

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): November 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: May 14, 2026
• First Submitted That Met QC Criteria: May 20, 2026
• First Posted (Actual): May 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urolithiasis; Ureteral Diseases; Ureterolithiasis
• Other Study ID Numbers: STUDY-26-00168

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: protecting participant privacy/confidentiality

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No