Abstract
PurposeAdvancements in endoscopy offer the possibility of inspection of intrarenal anatomy and pathology. The aim of the study was to evaluate renal papillary appearance in kidney stone formers and to correlate papillary findings with stone type and patient metabolic data.Materials and methodsA consecutive cohort of 46 kidney stone formers undergoing retrograde intrarenal surgery was enrolled. During surgery, renal papillae were characterized in the domains of ductal Plugging (DP), surface Pitting, Loss of papillary contour, and Amount of Randall’s plaque (RP, PPLA scoring). Stone material was analyzed using micro-CT and infrared spectroscopy, and blood and urine were collected for metabolic evaluation.ResultsIn all patients, renal papillae had changes in at least one of the domains of the PPLA score. Examining the total population, it was evident that patients with predominantly plugging (DP > 0) all had very low RP scores. There were no significant trends between mean PPLA scores and urinary analytes for the total group.ConclusionEfforts to prevent renal stone formation have so far been insufficient in majority of patients. Digital endoscopy reveals that kidney stone formers have different and distinct papillary morphologies that seem to be linked to specific stone-forming pathways. Since renal papillary abnormalities may be easily identified during endoscopy, this may in the future prove to be an important method for tailoring prevention strategies in kidney stone patients.
Highlights
Nephrolithiasis is a common disease throughout the world; the lifetime risk of developing kidney stones in Europe and USA is estimated to be 10–15% [1, 2] and kidney stone disease represents a major burden to quality of life [3].Eight decades ago, Alexander Randall proposed subepithelial calcium phosphate deposits at the tip of the renal papillae as the origin of renal calculi [4]
Based on infrared spectroscopy (IR) and micro-CT, patients were classified as calcium oxalate (CaOx) stone formers if their stones contained > 50% CaOx monohydrate (COM), C aOx dihydrate (COD) or a combination of COM/COD
The present series has confirmed that renal stone formers do have distinct papillary changes that may be characterized using the domains of the PPLA scoring system: ductal Plugging (DP), surface pitting (SP), loss of contour (LC), and Randall’s plaque (RP) [14]
Summary
Alexander Randall proposed subepithelial calcium phosphate deposits at the tip of the renal papillae as the origin of renal calculi [4] World Journal of Urology (2019) 37:2207–2215 forming stones on RP, whereas other histopathological findings with intratubular crystals have been identified as unique for stone formers with other types of stone diseases [12, 13]. The aim of the present study was to evaluate renal papillary appearance in a consecutive cohort of kidney stone formers undergoing retrograde intrarenal stone surgery (RIRS) using digital flexible ureteroscopes and to correlate the papillary findings with stone type and patient metabolic data to explore the role of endoscopic papillary findings in defining underlying stoneforming mechanisms and clinical outcomes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
