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Sources of Funding: None

Introduction

According to the European Association of Urology Urolithiasis Guidelines, ureteral stenting reduces the risk of renal colic and obstruction, and many physicians consider inserting ureteral stents before SWL to create an artificial chamber with an improved stone-fluid interface for better fragmentation during SWL and to reduce the risk of obstruction. Accordingly, several studies have been performed to determine whether routine pre-SWL ureteral stenting is helpful in preventing obstructive complications, but the issue remains somewhat controversial. Thus, the current study was conducted to evaluate the effects of ureteral stenting and stone characteristics on ureteral stone clearance and to estimate the probability of one-session success in SWL patients with ureteral calculi according to whether they underwent ureteral stenting or exhibited various other factors.

Methods

We retrospectively reviewed the medical records of 1,651 patients who underwent their first SWL. Among these patients, 680 had a ureteral stone measuring 4-20 mm and were thus eligible for our study. The 57 patients who underwent ureteral stenting during SWL were identified. Maximal stone length (MSL), mean stone density (MSD), skin-to-stone distance (SSD), and stone heterogeneity index (SHI) were determined by pre-SWL non-contrast computed tomography.

Results

After propensity score matching, 399 patients were extracted from the total patient cohort. There were no significant differences between stenting and stentless groups after matching, except for a higher one-session success rate in the stentless group (78.6% versus 49.1%; P=0.026). In multivariate analysis, shorter MSL, lower MSD, higher SHI, and absence of a stent were positive predictors for one-session success in patients who underwent SWL. Using cut-off values of MSL and MSD obtained from receiver operator curve analysis, in patients with a lower MSD (≤784 HU), the success rate was lower in those with a stent (61.1%) than in those without (83.5%) (P=0.001). However, in patients with a higher MSL (>10 mm), the success rate was lower in those with a stent (23.6%) than in those without (52.2%) (P=0.002).

Conclusions

Ureteral stenting during SWL was a negative predictor of one-session success in patients with a ureteral stone.

Funding

None