Predicting ureteral status below the ureteral calculi in patients undergoing ureteroscopic lithotomy

Abstract

Background During ureteroscopy, severe ureter straightness or contortion may occur before the stone is passed. Purpose To identify clinical factors associated with distal ureteral status below the ureteral calculi in patients before surgery. Material and Methods From October 2016 to March 2017, 101 patients with ureteral calculi who underwent ureteroscopic lithotripsy were reviewed. Patients who lacked clinical data and underwent preoperative indwelling ureteral stent placement were excluded. Univariate and multivariate analyses were performed to determine the clinical factors associated with intraoperative findings. Results A total of 101 patients were enrolled in the study (mean age  =  54 years; mean stone size  =  7.9 ± 4.5 mm). Overall, 25 of the 101 patients (24.7%) were diagnosed with poor distal ureteral status defined as intraoperative ureterostenosis or contortion resulting in a ureteroscope being unable to pass during the initial attempt. Univariate analysis showed significant differences in renal parenchyma thickness, ureteral wall thickening on imaging, and stone location (all, P < 0.05) with and without poor distal ureteral status. On multivariable analysis, renal parenchyma thickness (adjusted odds ratio [aOR] 0.288; 95% confidence interval [CI] 0.099–0.838; P = 0.022) and ureteral wall thickening on imaging (aOR 6.114; 95% CI 2.015–18.548; P = 0.001) independently predicted poor distal ureteral status. However, only renal parenchyma thickness was associated with severe ureter straightness or tortuosity that resulted in conversion. Conclusion In conclusion, renal parenchyma thickness and ureteral wall thickening on imaging were associated with poor distal ureteral status. Therefore, patients with these predictive factors should undergo more intensive preparation before surgery.