Advantages of upper calyx puncture in mini-endoscopic combined intrarenal surgery: a retrospective comparative...

To evaluate the clinical advantages and risks of upper calyx puncture (UCP) for renal stones in patients undergoing mini-endoscopic combined intrarenal surgery (mini-ECIRS).

We retrospectively analyzed 331 patients who underwent single-tract mini-ECIRS at our institution between 2015 and 2020. Clinical outcomes, including stone-free rate (SFR), complications (Clavien-Dindo classification), operative time, fluoroscopy time, length of hospitalization, and postoperative drainage strategy, were compared between the UCP (n = 169) and non-UCP (n = 162) groups.

The UCP group had significantly larger stone diameters (25 mm vs. 23 mm, p = 0.027), burdens (31 mm vs. 28 mm, p = 0.004), stone surface areas (SSA: 371 mm^2 vs. 294 mm^2, p = 0.003), and volumes (5.73 vs. 4.26 cm^3, p = 0.001) than those in the non-UCP group. Computed tomography-based SFR did not differ significantly between the groups (UCP, 86.4%; non-UCP, 82.7%; p = 0.366). Analyses of Clavien-Dindo classification showed no significant differences. However, operative time (95.0 vs. 106.5 min, p = 0.001) and fluoroscopy time (1.1 vs. 1.9 min, p < 0.001) were significantly shorter in the UCP group. The length of hospital stay did not significantly differ (4.0 vs. 4.0 days, p = 0.095). Postoperative drainage differed between groups: nephrostomy alone was more frequent in the UCP group (47.3% vs. 29.0%), whereas stent-only drainage was more frequent in the non-UCP group (15.4% vs. 31.5%, p = 0.0023). Additionally, ureteral stent placement at discharge was significantly less common in the UCP group (37.3% vs. 56.8%, p = 0.001), potentially reducing stent-related discomfort during outpatient follow-up.

UCP in mini-ECIRS is associated with improved intraoperative visibility and shorter operative and fluoroscopy times, and reduced need for postoperative ureteral stenting, even in cases with larger stone burdens, without an increase in postoperative complications. These findings suggest that UCP may offer procedural advantages and contribute to improved postoperative comfort in appropriately selected patients.