Estudo anatômico e radiológico do sistema pielocalicial do rim em ferradura e da duplicação pieloureteral aplicado ao tratamento da litíase do polo inferior e ao treinamento em endourologia

Abstract

The objective of this paper is to analyze the three-dimensional intra-renal anatomy of the human horseshoe kidney (HK) and the kidneys with complete ureteral duplication (CUD). We analyzed 20 three-dimensional (3D) polyester resin endocasts of the kidney collecting system belonging to our research unit. Among than, three were horseshoe kidneys (HK), seven had complete ureteral duplication (CUD) and ten 3D endocasts of kidneys without macroscopic anomalies (Control group - CG). We also analyzed 24 patients with 3D computerized tomography scan (CT-scan) reconstruction images of kidneys; among than, six were patients with HK, and eight had CUD kidneys; also, CT scans of 10 patients without kidney anomalies were used as CG. There were studied the number of calyces, width and length of the infundibulum and the minor calyces and the angles between the lower infundibulum and renal pelvis (LIP) and between the lower infundibulum and the lower minor calyces (LIICA) in the lower pole. We also studied usable data of 2 patients with horseshoe kidneys and 2 patients with pyeloureteral duplication were obtained from CT-scan as Digital Imaging and Communications in Medicine (DICOM) format of a brazilian public health unit. These DICOM images were processed with Simplify3D® software and were printed using a Flashforge Dreamer® 2018 printer. The models were made of Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) with 1.75 millimeters of diameter. The navigation was obtained by the same observer with a digital flexible ureteroscopy (3.3x670mm model DR030670, Endomaster®). Mean averages were statistically compared using the ANOVA with the Kruskal-Wallis test, Tukey-Krammer test and Unpaired t test (p-value < 0.05 was considered statistically significant). The data were analyzed with the IBM® SPSS® Statistics. There was no statistical difference in the measurements of the inferior pole (length and width of major and minor calyces, and LIICA) between the groups with anomalies and the control group, both in polyester resin endocasts and in 3D CT-scan reconstruction images, as well for the LIP in the resin endocasts. We observed statistical difference when we compared the LIP in the 3D CT-scan between HK versus CUD (p= 0.003) and HK versus CG (p= 0.035). When we compared polyester resin endocasts versus 3D CT-scan reconstruction images, analyzing only the lower pole, we observed statistical difference: in LIP (p= 0.006), LIICA (p= < 0.001) and length of major calyces between CUD groups (0.034). The 3D printed kidney has a low cost manufacturing (about U$ 100), and it was relatively quick to make (on average 22 hours). The digital flexible ureteroscope was inserted into all molds and the entire collecting system (including the lower pole and perpendicular minor calices) was examined in horseshoe kidneys and pyeloureteral duplications. The knowledge of spatial anatomy of lower pole is of utmost importance during endourologic procedures in patients with kidney anomalies. In the present study we observed that horseshoe kidneys had more restrictive anatomic factors in lower pole than the complete ureteral duplication.