Role and Efficacy of Percutaneous 4.5-Fr Semi-Rigid Ureteroscope While Creating Through-And-Through Guidewire Passage During Minimally Invasive Endoscopic Combined Intrarenal Surgery in the Supine Position; Retrospective Study at a Single Institution.

Objective: This study was performed to evaluate the efficacy of using a percutaneous 4.5-Fr semi-rigid ureteroscope (4.5-rURS) and preoperative clinical factors in the performance of the through-and-through guidewire technique (T&TGW) under the guidance of retrograde flexible ureteroscope (fURS)-assisted fluoroscopy during minimally invasive endoscopic combined intrarenal surgery (mini-ECIRS).

Methods: In total, 123 patients who underwent mini-ECIRS with percutaneous 4.5-rURS assistance for large kidney stones in the flank-free modified Valdivia position were retrospectively evaluated. The primary outcome was the achievement rate of T&TGW, defined as percutaneous insertion of a guidewire that passed down the ureter and exited outside the external urethral meatus. The secondary outcome was the rate of percutaneous 4.5-rURS assistance required to successfully perform T&TGW.

Results: The stone-free rate was 81.2%, including no residual fragments in 72.3% of patients. T&TGW was successful in 119 (96.6%) patients, which was necessary using retrograde fURS-assisted fluoroscopic guidance in 61 (49.5%) patients, whereas 4.5-rURS assistance was required in 58 (47.1%) patients. Guidewire migration under the renal pelvis mucosa was found in 10 (8.1%) patients. Preoperative factors associated with failed T&TGW using retrograde fURS-assisted fluoroscopic guidance were the puncture site in the lower calyx (odds ratio, 0.125; confidence interval, 0.043-0.364; p = 0.001) and the presence of preoperative hydronephrosis in the renal calyx of the puncture site (odds ratio, 0.261; confidence interval, 0.093-0.730; p = 0.011).

Conclusion: Percutaneous 4.5-rURS assistance facilitated successful T&TGW in cases of failed access under retrograde fURS-assisted fluoroscopic guidance in supine mini-ECIRS and a useful option to find a migrated guidewire in the wrong direction.