Prevention of ureteral stone migration during percutaneous nephrolithotomy: a randomized controlled trial.

OBJECTIVE

With the increasing adoption of totally tubeless percutaneous nephrolithotomy (ttPCNL), prevention of stone fragment migration into the ureter has gained clinical importance. This study aimed to compare the incidence of ureteral fragment migration at the end of PCNL using a 5 Fr open-ended ureteral catheter (5FrUC) versus an occlusion balloon catheter (OBC).

METHODS

In this IRB-approved randomized controlled trial, 108 eligible patients were randomized 1:1 to either the 5FrUC or OBC group and 99 were included in the final analysis. The primary outcome, ureteral fragment migration, was defined as the presence of any stone fragment ≥ 1 mm between the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), confirmed by ureteroscopy at the conclusion of PCNL.

RESULTS

Baseline demographics, stone characteristics, and operative parameters were comparable between groups, confirming effective randomization. Ureteral fragments were detected in 10 patients (10%): 7 with a single fragment, 2 with two fragments, and 1 with more than three fragments. The median fragment size was 2 mm (range, 1-4 mm). The incidence of ureteral fragments was significantly higher in the 5FrUC group compared with the OBC group (17% vs. 4%, p = 0.03). Logistic regression analysis demonstrated that OBC use reduced the risk of ureteral fragment migration by approximately 80% compared with 5FrUC (OR = 0.204, 95%CI 0.041-1.001, p = 0.05). Greater total stone burden, larger stone volume, higher Guy's stone score, and presence of full staghorn calculi were also associated with fragment migration.

CONCLUSION

Use of an occlusion balloon catheter significantly reduced ureteral fragment migration compared with a 5 Fr open-ended ureteral catheter, achieving prevention in 96% of cases. Although the clinical impact of residual ureteral fragments remains uncertain, these findings support consideration of OBC use, particularly in ttPCNL procedures.