Impact of Lithotomy Position on Ureteral Course and Psoas Muscle: A Combined Survey and Radiological Evaluation by the Eau Endourology & Yau Endourology Working Groups

Background and Objective: To assess urologists’ perspectives on the impact of lithotomy position on the psoas muscle and ureteral course, and to radiologically evaluate these anatomical changes using a double J (DJ) stent as a marker. Methods A prospective study was conducted between January and June 2025. An 11-item web-based survey was distributed to fellowship-trained endourologists to explore perceptions regarding lithotomy positioning during ureterorenoscopy. For radiological assessment, adults aged 18–65 who underwent DJ stent placement after ureteroscopy were analyzed using KUB X-rays obtained in supine and standard lithotomy positions. Distances between stent segments and lumbar vertebrae, as well as intersegmental angles, were measured and compared according to BMI. Key Findings and Limitations: Fifty-three urologists completed the survey. Most reported that psoas muscle length decreases (67.9%) and width increases (66%) in lithotomy position. The standard dorsal lithotomy position was preferred by 60.4%, and 62.3% believed positioning could affect ureteroscope passage at the iliac vessel crossover. Adjustable leg supports were routinely used by 84.9%. Increasing lithotomy level was not considered to significantly influence complication rates (69.8%), operative time (58.5%), or stone-free rates (62.3%). Among 22 radiologically evaluated patients (mean age 51.9 years, 64.6% male), no significant differences were found in stent–vertebra distances or segmental angles between positions, nor across BMI groups. Conclusions and Clinical Implications: Although radiological analysis showed no measurable ureteral configuration changes, urologists perceive lithotomy positioning as potentially influential during endoscopic access. Further dynamic imaging and outcome-based studies are warranted to clarify its clinical significance.