Reverse Trendelenburg Lithotomy with Certain Inclination Angles Reduces Stone Retropulsion during Ureteroscopic Lithotripsy for Proximal Ureteral Stone

Abstract

The objective of this study is to investigate how different inclination angles of reverse Trendelenburg lithotomy affect stone retropulsion and stone-free rates during ureteroscopic lithotripsy for proximal ureteral stones. Patients with proximal ureteral stones undergoing ureteroscopic lithotripsy in our institution between January 2019 and December 2020 were included according to predefined criteria. The rigid ureteroscope and Holmium: YAG laser were utilized to perform lithotripsy, and a stone basket was used to keep the stone in place and to avoid retropulsion. Before initiating lithotripsy, the upper part of the patient’s body was tilted up to establish a reverse Trendelenburg posture with appropriate inclination angles. To quantify the stone-free rate, computed tomography was used to evaluate the residual stones in the kidney one month following surgery. Patients’ clinical data were obtained retrospectively, including age, gender, the largest diameter of stone, stone density on computed tomography, and the distance between stone and ureteral pelvic junction, etc. Patients were divided into four groups based on the inclination angles of reverse Trendelenburg lithotomy: 0°, 10°, 20°, and 30°. The chi-square test was used to compare stone retropulsion and stone-free rates between groups. To discover possible determinants of the stone-free rate, logistic regression analyses were used. There were 189 patients that qualified. There were no differences in clinical characteristics between groups (p > 0.05). Multiple comparisons between groups revealed that the 20° and 30° groups had less retropulsion and a greater stone-free rate than the 0° and 10° groups (p < 0.05), whereas there were no significant differences in stone retropulsion or stone-free rates between the 20° and 30° groups or between the 0° and 10° groups (p > 0.05). The inclination angles as well as distance between the stone and ureteral pelvic junction were identified by using logistic regression analyses as the related factors for the stone-free rate. According to our results, the appropriate inclination angles of reverse Trendelenburg lithotomy during ureteroscopic lithotripsy for proximal ureteral stones would help preclude stone retropulsion and increase the stone-free rate.

Keywords: lithotripsy; proximal ureteral calculi; reverse Trendelenburg position; stone-free rate; ureteroscopy; urolithiasis.