Retrograde Ureteral Catheterization Is Not Essential in Percutaneous Nephrolithotomy: A Randomized Controlled Trial

Percutaneous nephrolithotomy (PCNL) is currently the first-line treatment for upper urinary tract stones larger than 2 cm. It is minimally invasive and enables rapid recovery, thus winning the approval of patients . In the traditional PCNL procedure, a ureteral catheter is first retrogradely inserted into the ureter on the affected side with the patient in the lithotomy position, and then the patient is changed to the prone position for percutaneous renal puncture and stone extraction . The inserted catheter can be used for retrograde injection of water or contrast agents, which facilitates percutaneous renal puncture and also prevents stone fragments from entering the ureter during the lithotripsy process . However, under the lithotomy position, disinfection, draping, and intubation are carried out first, and then the patient is turned to the prone position for another round of disinfection and draping, which is cumbersome and requires a long surgical preparation time. In recent years, with the enrichment of urologists' experience in percutaneous renal puncture and the improvement of the quality of ultrasound images, the application of percutaneous renal puncture and fistulization guided by ultrasound has become more and more widespread . Experienced urologists can even puncture the target renal calyx without the need for retrograde intubation and injection of water to form an "artificial hydronephrosis". Combined with intraoperative contrast verification through the puncture needle, accurate puncture can be ensured. This saves the surgical time required for the traditional PCNL, which involves retrograde intubation in the lithotomy position followed by a change to the prone position, and also avoids the risk of infection that may be increased due to elevated renal pelvic pressure during retrograde injection. However, failure to place a retrograde catheter during PCNL may increase the difficulty of puncture and the risk of stone fragments entering the ureter durin