[Roadmap of ultrasound-guided percutaneous access to the renal collecting system].

Introduction: The key point of successful PCNL is getting access to the renal collecting system. Ureteral catheterization and injection of contrast material provide an important advantage of visualizing and dilating the collecting system. However, catheterization increases the operation time, exposure to anesthesia, and requires additional reusable and disposable medical supplies. The purpose of the study was to develop a surgical algorithm for accessing the renal collecting system for mini-PCNL without catheterization.

Materials And Methods: We analyzed the treatment results of 82 patients with a single kidney stone, who underwent mini-PCNL without prior catheterization of the ureter. The percutaneous access was obtained according to the roadmap we had developed. The puncture was performed under X-ray control and US guidance. For a calyx stone, the puncture was performed "to the stone". For a pelvis stone, the targeted calyx was accessed using the following algorithm where each next step was performed if the puncture had been impossible at the previous one: 1. 30 min before the operation: infusion load of normal saline, 1000 ml. 2. Intraoperatively: intravenous furosemide, 60 mg. 3. Puncture "to the pelvic stone", injecting contrast material into the collecting system and correcting the access puncture through the required calyx.

Results: In all 82 cases, puncture access was performed without ureteral catheterization. In 20 patients with calyceal stones, puncture onto a stone was successfully performed in 100% of the cases. Of 62 patients with pelvic stones, preliminary infusion was enough to allow a successful puncture in 49 (79%), access after intravenous administration of furosemide was obtained in 13 (21%), and a primary puncture onto a pelvic stone had to be done in 6 (10%) patients.

Conclusions: Our proposed algorithm for accessing the PCS of the kidney was successfully used in 100% of the cases. It makes possible to avoid routine ureteral catheterization and thus reduce the overall operation time and the risk of complications, as well as save medical supplies. Clearly, such results require that the surgeon should have significant experience with puncture interventions under ultrasound control.