Proposal for a Simple Anatomical Classification of the Pelvicaliceal System for Endoscopic Surgery

Abstract We herein propose a nomenclature for renal calices and anatomical classification of the renal pelvis for endoscopic surgery. We prospectively collected data on a total of 270 patients (540 kidneys) who underwent CT-urography. We then constructed three-dimensional images of the renal pelvis and examined their morphologic classification. Forty-eight kidneys were excluded from this study because of severe hydronephrosis or large renal cysts. The remaining 492 kidneys were included. We systematically categorized each minor calix into five levels: top, upper, middle, lower, and bottom. The upper, middle, and lower calices were typically found in pairs: anterior and posterior. The most common total number of minor calices was eight (51%), followed by seven (30%). We also classified the form of the pelvis into type I: single pelvis (58%) and type II: divided pelvis (42%), according to the branch patterns of the renal pelvis. In type II, the renal pelvis is always bifurcated into the upper branch (top an...