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NCT Number: NCT07310966

Comparison of Lithotomy Versus Lateral Position in Retrograde Intrarenal Surgery for Lower Calyceal Stones Less Than 2 cm

Retrograde intrarenal surgery (RIRS) is an established minimally invasive treatment for renal stones, particularly for lower calyceal stones less than 2 cm, offering acceptable stone-free rates with low morbidity.

However, stone clearance in the lower calyx remains technically challenging due to unfavorable anatomy, limited scope deflection, and gravity-dependent fragment retention. Patient positioning during RIRS has been suggested as a modifiable factor that may influence endoscopic access, stone relocation, and surgical ergonomics.

The lithotomy position is conventionally used during RIRS, while the lateral position has been proposed to facilitate stone migration and improve lower calyceal access through gravitational assistance. Existing studies comparing patient positioning during RIRS are limited, with most evidence derived from retrospective analyses or non-randomized designs.

Therefore, this randomized controlled trial aims to compare lithotomy versus lateral positioning during RIRS for lower calyceal stones less than 2 cm in terms of operative and clinical outcomes.

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Key information

Conditions

Renal Calculi Calculi Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Kidney Calculi Kidney Diseases Male Urogenital Diseases Nephrolithiasis Pathological Conditions, Anatomical Pathological Conditions, Signs and Symptoms Urinary Calculi Urogenital Diseases Urolithiasis Urologic Diseases

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged ≥18 years.
  • Single or multiple lower calyceal renal stones with stone size <2 cm confirmed by NCCT.
  • Negative urine culture.
  • Presented cases.

Exclusion criteria

  • Multiple stones involving renal pelvis or other calyces.
  • Anatomical anomalies affecting ureteroscope access (horseshoe kidney, malrotation, ureteral strictures).
  • Pregnancy.
  • Prior ipsilateral renal surgery.

Treatment and study plan

Lithotomy Position

Procedure

Patients undergo RIRS in lithotomy position

Lateral position

Procedure

Patients undergo RIRS in lateral position

Primary outcomes

  1. Stone Free Rate

    Time frame: 1 month

    Stone-free rate (SFR), defined as no clinically significant residual stones on non-contrast 3-mm-cuts CT, measured as yes or no

Secondary outcomes

  1. Operative time

    Time frame: The operative time

    operative time is defined as time between starting the procedure and termination of it measured in minutes

  2. Complications

    Time frame: 1 month

    Intra and postoperative complications, defined as complications happens intraoperative and postoperatively, graded by modified clavien-dindo classification

Study contacts

Contact information is provided by the study sponsor or research team.

Ammar Alorabi

CONTACT

[email protected]

+201067608011

Sponsors and collaborators

Lead sponsor

Menoufia University

Other

Registry information

Official study title

Comparison of Lithotomy Versus Lateral Position in Retrograde Intrarenal Surgery for Lower Calyceal Stones Less Than 2 cm: A Randomized Controlled Trial

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Dec 30, 2025
Registry last updated
Dec 30, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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