Analysis of the effectiveness and safety of 7.5 Fr ultra-thin flexible ureteroscope combined with a tip-flexible suctioning ureteral access sheath for the treatment of kidney stones.

Objective: To compare the efficacy and safety of using a 7.5 Fr flexible ureteroscope (f-URS) with tip-flexible suctioning ureteral access sheath (TFS-UAS) versus a 9.2 Fr f-URS with traditional ureteral access sheath (T-UAS) in the treatment of kidney stones.

Methods: A retrospective analysis was conducted on 205 patients with kidney stones measuring 1.0-2.0 cm treated with 7.5 Fr and 9.2 Fr f-URS in the Urology Department of The Affiliated Dazu Hospital of Chongqing Medical University from November 2022 to November 2023. The patients were randomly divided into two groups. Among them, 78 patients were selected to use the 7.5 Fr f-URS, which was designated as the GroupA. The remaining 127 patients were selected to use the 9.2 Fr f-URS, which served as the GroupB. The study compared the operation duration, lithotripsy duration, surgical success rate, immediate postoperative stone-free rate (SFR), 1-month postoperative SFR, and the incidence rate of postoperative complications between the two patient groups.

Results: In terms of demographic characteristics, the size of calculi, surgical success rate, and 1-month postoperative SFR, there was no statistically significant difference between GroupA and GroupB. However, GroupA demonstrated superior performance compared to GroupB in operation duration (48 (40.55) min vs 74 (56.94) min), lithotripsy duration (35 (27.43) min vs 59 (42.78) min), and immediate postoperative SFR (53.52% (38/71) vs 29.41% (35/119)), with statistically significant differences observed (P < 0.05). In terms of complication occurrence, GroupA reported 10 cases of minor (Grade 1) complications, whereas GroupB had 32 cases of minor (Grade 1) complications and 7 cases of severe complications (including 2 cases of Grade 3 and 5 cases of Grade 4). The difference between the two groups was statistically significant (P < 0.05). The GroupA reported significantly fewer cases of postoperative fever (4) and analgesic treatment (3) compared to GroupB, which had 18 fever cases and 19 analgesic cases (P < 0.05).The GroupA did not experience any cases of septicemia or steinstrasse. Conversely, the GroupB had 5 cases of septicemia and 3 cases of steinstrasse, including 2 patients who underwent reoperation. Both groups also reported cases of ureteral mucosal rupture (5 in GroupA, 10 in GroupB), but these differences were not statistically significant (P > 0.05).

Conclusion: Compared with 9.2 Fr f-URS combined with T-UAS, the use of 7.5 Fr f-URS with TFS-UAS in the treatment of kidney stones has higher lithotripsy efficiency and lower complication rate. This combination is safe and effective in the treatment of kidney stones.