Endoscopic identification of urinary stone composition: A study of South Eastern Group for Urolithiasis Research (SEGUR 2). / Identificación endoscópica de la composición de los cálculos urinarios: un estudio del Southeastern Group for Lithiasis Research (SEGUR 2).

ABSTRACT

INTRODUCTION AND OBJECTIVES: To assess the surgeon's ability to evaluate the composition of the stone by observation of endoscopic images. MATERIALS AND METHODS: A series of 20 video clips of endoscopic treatments of urinary stones of which was also available the result of infrared spectroscopy was uploaded to a YouTube site accessible only to members of the South Eastern Group for Urolithiasis Research (SEGUR) who were asked to identify the composition of the stones. RESULTS: A total of 32 clinicians from 9 different countries participated in the study. The average number of correct detections of participants was 7.81 ± 2.68 (range 1-12). Overall accuracy was 39% (250 out of 640 predictions). Calcium oxalate dihydrate stones have been correctly detected in 69.8%, calcium oxalate monohydrate in 41.8%, uric acid in 33.3%, calcium oxalate/uric acid in 34.3% and cystine in 78.1%. Precision rates for struvite (15.6%), calcium phosphate (0%) and mixed calcium oxalate/calcium phosphate (9.3%) were quite low. CONCLUSIONS: Observation of the stone during the endoscopic procedure was not reliable to identify the composition of most stones although it gave some information allowing to identify with a good sensitivity calcium oxalate dihydrate and cystine stones. Nevertheless, photo or video reporting of the intact stone and its internal structure could should be encouraged to implement results of still mandatory post-operative stone analysis. Endourologists should improve their ability of visual identification of the different types of stones.