Intrarenal pressure monitoring in retrograde intrarenal surgery for high-infectious risk populations

To evaluate the feasibility of real-time intrarenal pressure (IRP) monitoring using the LithoVue™ Elite (LVE) ureteroscope and assess postoperative infectious complications after retrograde intrarenal surgery (RIRS) in patients with positive urine cultures.

This multicenter, single-arm, prospective cohort study (August 2023-October 2024) included patients with upper urinary tract calculi and positive preoperative urine cultures who underwent RIRS with real-time IRP monitoring via the LVE. Irrigation was adjusted to maintain IRPs below 30 mmHg. The primary endpoint was postoperative fever ≥ 38 °C. Secondary endpoints included systemic inflammatory response syndrome (SIRS), stone-free rates, ipsilateral flank pain scores, and complications.

Of 148 eligible patients, 104 were enrolled. The median operative time and artificial intelligence-corrected IRP were 50 min (interquartile range: 36.8-80.0) and 13.3 mmHg (10.4-19.1), respectively. Postoperative fever occurred in 7.7% of patients, SIRS in 3.8%, and no septic shock was observed. Patients who developed postoperative fever were older (p = 0.019) and had longer preoperative ureteral stent indwelling times (p = 0.015). Univariable linear regression analysis demonstrated that higher body mass index (BMI), irrigation method, and ureteral access sheath tip location were significantly associated with higher intraoperative IRP (all p ≤ 0.005). Higher postoperative white blood cell counts and ipsilateral flank pain scores were also associated with elevated IRP (p = 0.010 and p = 0.032, respectively). In multivariable linear regression analysis, higher BMI and manual irrigation remained independent increased intraoperative IRP predictors (p = 0.042 and p = 0.009, respectively).

Real-time IRP monitoring using the LVE ureteroscope maintained low intrarenal pressures during RIRS and was associated with a low rate of postoperative fever in high-risk patients. These findings suggest that incorporating IRP monitoring into RIRS protocols is feasible and may improve pressure management in patients with positive urine cultures.