Definition of clinically insignificant residual fragments after percutaneous nephrolithotomy among urologists: a world-wide survey by EAU-YAU Endourology and Urolithiasis Working Group.

Introduction: The aim of this article was to evaluate the current perception of urologists as to what size is considered as a clinically insignificant residual fragment (CIRF). Material and methods: A survey was globally distributed to the members of the Endourological Society via SurveyMonkey. Results: A total of 385 participants responded to the survey on CIRF. Most participants considered 2 mm (29%) as CIRF threshold, followed by 3 mm (24%), 4 mm (22%), 0 mm (14%), 5 mm (8%) and 1 mm (3%). North American urologists considered CIRF to be smaller than urologists from Asia, Eurasia and South America, (p-values ≤0.001, 0.037 and 0.015 respectively). European urologists identified smaller CIRF in comparison to Asian urologists (p-value = 0.001). Urologists mainly using a pneumatic lithotripter accepted larger fragments as CIRF, compared to urologists mainly using ultrasonic devices or a combination of ultrasonic and pneumatic devices (p-value = 0.026 and 0.005 respectively). Similarly, urologists mainly performing X-Ray and ultrasound as post-operative imaging accepted larger fragments as CIRF in comparison to urologists mainly performing non-contrast computed tomography (p-value = 0.001). Conclusions: What is considered as CIRF varies between urologist from different continents and seems to be associated with the lithotripter used and the post-operative imaging modality of preference to assess treatment success.