Loop-tail stents fail in reducing stent-related symptoms: results of a prospective randomised controlled trial

Objective: To compare stent-related symptoms (SRS) of loop-tail (LT) and conventional double J (DJ) stents after uncomplicated flexible ureterorenoscopy (fURS), in a prospective randomised controlled single-blind parallel-group study. Patients and Methods: Patients undergoing fURS were randomised into two groups: the LT Group received LT stents (Polaris™ Loop) and the DJ Group received conventional DJ stents (Vortek®). The stent was removed after 4 weeks. The Ureteric Stent Symptom Questionnaire (USSQ) was administered at 2 days, 4 and 8 weeks (baseline evaluation) after stent insertion. The primary endpoint was to compare the Urinary Symptom Index Score of the LT vs DJ groups at 4 weeks after stent insertion. The secondary endpoints were to compare the USSQ domains’ subscores at 2 days and 4 weeks after stent insertion, USSQ single answers at 4 weeks, and the 4-week USSQ domains’ subscores adjusted for baseline. Results: A total of 68 patients were randomised (34 LT and 34 DJ). The answers given at 4 weeks were not significantly different between the two groups for the Urinary Symptom Index Score (P = 0.982), Pain Index Score (P = 0.169), visual analogue scale (P = 0.276), and all the other domains of the USSQ. At 4 weeks, the single-answer analysis did not find any differences between the groups; the urinary symptoms were all comparable, as was the requirement for pain painkillers (P = 0.684) and pain during sex (P = 0.496). There were also no significant differences for every single domain score for the responses given at 2 days. The same applied to USSQ subscores at 4 weeks adjusted for the 8-week baseline results, which were also comparable. Conclusions: The study found no differences in terms of SRS between the LT and DJ groups, either at 2 days or 4 weeks after stent insertion, with or without baseline correction.