An interventional study of Reverse Trendelenburg Position and T-Tilt Position in Ureteral Stone, sponsored by Icahn School of Medicine at Mount Sinai. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-04.
Sponsored by Icahn School of Medicine at Mount Sinai · Not applicable, Interventional, and Treatment
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.
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.
84 studies on the registry are indexed under Ureterolithiasis; 19 are open to participants now.
This study's planned enrollment of 54 is below the median of 101 across 66 interventional studies indexed under Ureterolithiasis.
Browse Ureterolithiasis studies →Icahn School of Medicine at Mount Sinai is the lead sponsor of 776 studies on the registry; 176 are open to participants now.
Of its 125 completed or terminated interventional studies of FDA-regulated products, 83 (66%) have results posted.
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Exclusion criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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.
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.
Total operative time
Operative time will be used to compare procedural efficiency
Time frame: Immediately postoperatively on the day of surgery
Proportion of participants stone-free
Proportion of participants without residual stone fragments on postoperative CT imaging
Time frame: 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
Time frame: 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
Time frame: 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.
Time frame: Through postoperative day 30
Plan to share: No — protecting participant privacy/confidentiality
No publications or documents are linked to this record.
Started May 2026 (actual). Primary completion is estimated for Nov 2027, 18 months after the start.
Of 36 non-industry interventional studies with no phase under Ureterolithiasis, half reached primary completion within 19 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 30. This study's planned 18 months is close to that.
Counting every sponsor, half of 38 studies reached it within 20 months; a quarter within 11 and three quarters within 30.
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