TOPOGRAPHIC-ANATOMICAL PECULIARITIES OF THE RENAL CALIXPELVIS SYSTEM IN THE FETAL PERIOD OF A HUMAN ONTOGENESIS

The study of the features of the topographic anatomy and individual anatomical variability of the renal calix-pelvis system (RCPS) during the fetal period of a human being intrauterine development (IUD) is important for elucidation and understanding of the complex transformations of their structure, syntopy and skeletotopy, in particular, to explain the causes and time of appearance of the structural variants, possible origin of the congenital malformations of the organ. Purpose of the work: to find out the dynamics of topographic and anatomical changes and anatomical variability of the renal calyx-pelvis system in the fetal period of human  ontogenesis. Material and methods. 102 biomannequin of a human being fetuses of 160.0-480.0 mm parietal-coccygeal length (PCL) (4-10 months of IUD) were studied. A complex of methods of morphological research was applied, which included anthropometry, morphometry, injections of blood vessels with X-ray contrast mixtures, X-ray techniques, dissection, microscopy, three-dimensional reconstruction and statistical analysis. Results. It has been found that a lobar structure of the kidneys of human fetuses is observed on all specimens. Two main variants of their external structure were revealed – bean-shaped and oval-shaped. At the beginning of the fetal period of human ontogenesis, the oval shape of the kidney is most often observed, but from the 6th month of the IUD, the bean-shaped form begins to prevail, and from the 8th month of the IUD it is determined almost twice as often. Two variants of the structure of the renal hilum were observed – their open and compact forms. Until the 6th month of IUD, the open form of the renal hilum prevails, and from the end of the 7th month and at the beginning of the 8th months of IUD, a compact form of the organ hilus was revealed on most preparations. In 10-month-old human fetuses, the compact form occurs almost three times more often than the open one. Simultaneously with changes in the shape of the renal hilum, changes in their holotopy occur: in 4-7-month-old fetuses, the hilus is directed forward and medially, and from the 8th month of IUD they are reoriented and placed already on the medial surface of the kidney. Among the variants of the structure of the RCPS, we observed ampullar and branched types. During the study of the renal pelvis skeletotopy, it has been found that at the beginning of the fetal period (4-5-months-old fetuses), the right and left renal pelvis are located almost at the same level in relation to the spine – approximately at the level of the interval between the II and III lumbar vertebrae, but starting from the 6th month, they "rise" on the left to the level of the middle third of the II lumbar vertebra, and on the right, on the contrary, "descend" to the middle third of the III lumbar vertebra. Syntopy of the renal pelvis and pyelo-ureteral segment with renal vessels on the right and on the left is almost the same, and in the dynamics of the fetal period of IUD does not change significantly. Conclusions. 1. The topography of the renal calyx-pelvic system is largely determined by the peculiarities of the spatial structure of the kidney – its external shape, size, skeletotopy, individual features of the hilum of the organ, their syntopy with the renal vessels. 2. Close syntopy of the renal pelvis and pyelo-ureteral segment with renal vessels with a compact form of the renal hilum may be an anatomical prerequisite for impaired urodynamics, provided there are variants of renal vessels branching or the existence of an abnormal vessel in the renal hilum region. 3. Variants of the structure of the kidneys and their structures are clearly observed from the beginning of the fetal period of human intrauterine development, significantly affect the topography of the calyces and pelvis, and in some cases can cause impairment of urodynamics.