To evaluate the efficacy and safety of bilateral intrarenal pressure (IRP) measurement using sensor wire during retrograde intrarenal surgery (RIRS) for patients with bilateral urolithiasis.

In eight patients with bilateral renal stones, a total of 16 IRP profiles were analyzed by performing both RIRS. The IRP was measured using PressureWire X Guidewire placed at the ureteropelvic junction (UPJ) on both sides. The mean IRP was recorded at each stage: baseline, ureteral access sheath (UAS) insertion, flexible ureteroscopy, fragmentation and basketing, and UAS removal. Throughout all procedures, the normal IRP on the contralateral side was simultaneously monitored to compare with the elevated IRP during RIRS on the affected side. Postoperative infectious complications and changes in renal function were also assessed.

In all 16 RIRS procedures, the sensor wire was appropriately positioned at the UPJ, and the IRP was properly monitored. The stonefree rate was 95.4%, and no significant ureteral injuries, postoperative infectious complications, or renal function deterioration were observed in any of the patients. When analyzing the 16 IRP profiles, an average increase of 24.94±3.90 mmHg was observed during RIRS compared to the normal IRP on the contralateral side. Specifically, the IRP showed the greatest increase during UAS insertion compared to normal IRP (34.57±16.79 mmHg), and the least change was observed during fragmentation and basketing (19.53±9.01 mmHg).

Simultaneously monitoring bilateral IRP is a feasible method to objectively assess intraoperative changes in IRP within a single patient, with an average increase of approximately 25 mmHg observed. Notably, the greatest increase in IRP occurs during the UAS insertion process in RIRS. Therefore, particular attention to this stage is crucial for enhancing the safety of RIRS procedures.