Active migration technique versus in situ lithotripsy technique in RIRS for 1-2 cm middle and upper ureteral stones: a prospective, randomized controlled study

To observe the efficacy and safety of the active migration technique and in situ lithotripsy technique in retrograde intrarenal surgery (RIRS) for patients with 1–2 cm middle and upper ureteral stones. 207 patients were enrolled in the study, of which 103 included in the study group received active migration lithotripsy and 104 included in the control group received in situ lithotripsy. The primary study outcome was the stone-free rate (SFR) on the first postoperative day. Secondary outcomes included the total SFR 4 weeks postoperatively, operative time, reduction in the hemoglobin levels, the length of postoperative hospital stay, the incidence of ureteral stricture at 3-month postoperatively, and any surgery-related complications. There was no obvious difference between two groups in patients’ demographics and preoperative clinical characteristics ( P  > 0.05). The operative time was significantly shorter in the study group than in the control group (57.1 vs. 62.5 min, P  < 0.001). The study group also had significantly higher immediate and total SFRs (81.5% vs. 64.4%, P  = 0.006, 90.3% vs. 77.9%, P  = 0.015, respectively). At 3 months postoperatively, the incidence of ureteral stricture in the study was statistically lower than in the control group (1.0% vs. 6.7%, P  = 0.032). Notablely, the overall complication rate was significantly lower in the study group than in the control group ( P  < 0.001). Our study provides evidence that the active migration technique, when combined with flexible and negative suction ureteral access sheath (FANS) in RIRS, results in a higher SFR and a lower complication rate than in situ lithotripsy for treating 1–2 cm middle and upper ureteral stones. The protocol for this study has been accepted by the Chinese Clinical Trial Registry (The registration number: ChiCTR2200056402; Date of registration: 03-06-2022).