Relative length of human kidney as more precise measuring of normal kidney

Abstract

Malformations in kidney development and kidney diseases are accompanied with changes in their size. For kidney evaluation in clinical practice, the kidney length is the most widely used measurement, since it provides the most precise results and it is easy to perform. Recently, the measurement of relative renal length has become more preferable as it takes into account the body height. The aim of this study was to measure both the absolute and relative length of normal cadaveric kidneys according to the body height, sex and age. In this study, we examined 95 adult cadaveric kidneys, without renal and vascular impairment, their age ranging from 23-87 years. To determine the period of the most abundant changes in kidney length, we separated them into a 10-year range. The relative renal length was calculated using the kidney length and body height ratio (kidney/body ratio). The absolute and relative length of left kidney in males was longer than the right one, with a statistically significant correlation. In females, the left kidney length was also longer than the right one, however, without a statistical significance. In contrast to the absolute length, the relative length of both kidneys did not show a significant difference between sexes, and did not manifest a significant decrease with age. There was a significant correlation between the kidney length and the subject's height. The relative renal length represents kidney size better than the absolute renal length because it eliminates sex and height differences until the age of 59 year. From the seventh decade of life, there is a significant decrease in both the absolute and relative renal length.