Direct ureteric length measurement from intravenous pyelography: does height represent ureteric length?

Abstract

Ureteric length is the most important factor for determining the ideal length of a ureteric stent. In most of the literature, ureteric length is estimated according to a patient’s height. We investigated the reliability of a patient’s height as a measure of ureteric length. We measured the actual length of the ureteric trace (ALUT) and the linear distance (LD) from the ureterorenal junction to the ureterovesical junction by intravenous pyelography (IVP), using a 15 min view. A total of 203 patients (100 men, 103 women, 406 ureters) with normal findings were studied, and ALUT, LD and height were measured. The mean patient height was 164.3±8.3(SD) cm. Mean ALUTs of the right and left ureters were 23.4±1.9 cm and 24.4±2.0 cm, respectively, and the mean LDs of the right and left ureters were 22.1±1.9 cm and 22.9±2.0 cm, respectively. Height was significantly correlated with the ALUTs of both sides, but these were not linear (r²=0.024 right, 0.059 left). However, LD showed significant linear correlations with the ALUTs of both sides (r²=0.879 right, 0.884 left). Two formulas to estimate the ALUT from LD were suggested: right ALUT=0.94×right LD+2.6, left ALUT=0.96×left LD+2.4. Our results demonstrated that patient height does not provide a reliable estimate of ureteric length. LD by IVP is preferable to patient height when estimating the ureteric length.