In Vivo Ureteroscopic Intra-Renal Pressures and Clinical Outcomes: A Multi-Institutional Analysis of 120 Consecutive Patients.

Abstract

To evaluate the pressures range generated in the human renal collecting system during ureteroscopy, in a large patient sample, and to investigate a relationship between IRP and outcome. A prospective multi-institutional study was conducted, with ethics board approval; February 2022-March 2023. Recruitment was of 120 consecutive consenting adult patients undergoing semi-rigid ureteroscopy and/or flexible ureterorenoscopy for urolithiasis or diagnostic purposes. Retrograde, fluoroscopy-guided insertion of 0.014" pressure guidewire (COMETTM II, Boston Scientific) to the renal pelvis. Baseline and continuous ureteroscopic intrarenal pressure recorded, alongside relevant operative variables. Thirty-day follow-up was completed. Descriptive statistics were applied to IRP traces with mean (SD) and maximum values and variance reported. Relationships between IRP and technical variables and IRP and clinical outcome were interrogated using chi-square and independent samples t-test. 430 pressure traces were analysed from 120 patient episodes. Baseline IRP was 16.45 ± 5.99mmHg. Mean intraoperative IRP varied by technique. IRP during semi-rigid ureteroscopy with gravity irrigation was 34.93 ± 11.66mmHg. Flexible ureterorenoscopy resulted in variable IRP values: from mean 26.78 ± 5.84mmHg (gravity irrigation; 12/14Fr ureteric access sheath (UAS)) to 87.27 ± 66.85mmHg (200mmHg pressurised-bag irrigation; 11/13Fr UAS). The highest single pressure peak was 334.2mmHg, during retrograde pyelography. Six patients (5%) developed postoperative urosepsis; these patients had significantly higher IRP during flexible ureterorenoscopy (81.7 ± 49.52mmHg) than controls (38.53 ± 22.6mmHg) p<0.001. A dynamic intrarenal pressure profile is observed during human in vivo ureteroscopy, with IRP frequently exceeding expected thresholds. A relationship appears to exist between elevated IRP and postoperative urosepsis.