Urolithiasis is a highly prevalent disease influenced by a wide range of factors multifactorial etiology results in the formation of urinary stones with diverse mineral compositions. Accurate identification of stone constituents is crucial for effective prevention of recurrence. Gold-standard methods for stone analysis are not always readily available in clinical practice. To address this, Daudon proposed a morphological classification system aimed at identifying stone types based on their surface characteristics. However, existing literature reports suboptimal accuracy of this method, largely due to technical limitations of endoscopic equipment. The primary objective of this study was to evaluate the reliability of morphological assessment in predicting stone mineral composition. Secondary aims included the identification of factors contributing to the consistently poor accuracy reported in previous studies.
An online quiz consisting of 20 single-choice questions was developed, each accompanied by a high-resolution image of a urinary stone and five predefined answer options. The reference stone composition for each image was determined using Fourier-transform infrared spectroscopy. Participants' performance was evaluated based on the percentage of correct responses per individual and per question. The results of specialists and residents were compared using the two-proportion Z-test, with statistical significance set at p <0.05.
A total of 779 responses were collected, with an overall accuracy rate of 33.7%. The most commonly selected answers were respectively oxalates, phosphates, uric acid, cystine, and infectious stones. Subgroup analysis revealed accuracy rates of 36% among attending physicians and 32% among residents, with no statistically significant difference. Notably, two participants achieved a perfect score (100%), supporting the internal validity of the test.
Detailed analysis revealed a wide distribution of scores, ranging from participants with only one correct response to those who completed the quiz with full accuracy. These results suggest that the consistently low diagnostic accuracy reported in the literature is more likely due to limited familiarity and lack of experience with the morphological classification, rather than inherent shortcomings of the system itself. The findings highlight the need for comprehensive endourology training programs focused on improving stone morphology recognition skills.
Central European journal of urology. 2025 Aug 31 [Epub]
Wojciech Tomczak, Katarzyna Grunwald, Klaudia Molik, Joanna Chorbińska, Łukasz Nowak, Jan Łaszkiewicz, Patryk Patrzałek, Mikołaj Przydacz, Magdalena Krajewska, Bartosz Małkiewicz, Tomasz Szydełko, Wojciech Krajewski
University Centre of Excellence in Urology, Wroclaw Medical University, Wroclaw, Poland., Department of Minimally Invasive and Robotic Urology, University Centre of Excellence in Urology, Wroclaw Medical University, Wroclaw, Poland., Department of Urology, Jagiellonian University Medical College, Krakow, Poland., Division of Nephrology, Transplantology and Clinical Immunology at 4 Military Clinical Hospital in Wroclaw, Faculty of Medicine, Wroclaw University of Science and Technology, Poland.