Which is the best method to estimate the actual ureteral length in patients undergoing ureteral stent placement?

Objectives: To define the best modality for estimating ureteral length in patients undergoing ureteral stent placement.

Methods: This study enrolled 151 patients (169 ureters) undergoing stent insertion. In all of them, an intravenous urography and non-contrast computed tomography were carried out. The actual ureteral length was determined by direct measurement using a 5-Fr ureteral catheter. A multivariate analysis evaluated the association between the ureteral length and each of the following parameters: body height, body surface area, ureteral trace by intravenous urography, linear distance (liner distance 1) from the ureteropelvic junction to the ureterovesical junction by intravenous urography, linear distance (liner distance 2) from the mid kidney to the ureterovesical junction by intravenous urography, and the distance from the level of the renal vein to the ureterovesical junction by axial computed tomography (axial computed tomography distance).

Results: The mean actual ureteral length was 23.2 cm (median 24 cm, range 16-29 cm). The Spearman correlation coefficients for body height, body surface area, ureteral trace, liner distance 1, liner distance 2 and axial computed tomography distance were 0.3126, 0.3076, 0.4541, 0.5230, 0.4796 and 0.6168, respectively. Axial computed tomography distance showed the best correlation with the actual ureteral length.

Conclusion: The axial computed tomography distance as calculated by the axial computed tomography can more reliably predict the actual ureteral length than other parameters. Further studies are required to show the best method for estimating the actual ureteral length in patients undergoing ureteral stent placement.