Do flexible ureteroscopies affect renal function?

To determine whether flexible ureteroscopies (f-URS) affect renal function by performing dynamic renal scans (DTPA or MAG3) pre- and post-operatively.

Between April 2010 and March 2024, 945 renal units underwent ureterorenoscopy, of which 101 renal units with upper urinary tract stones (UUTS) completed a renal scan, either DTPA or MAG3 pre- and post-f-URS. The cases were divided into three groups: worsened (>10%), improved (>10%), or unaffected (stable) renal function (⩽10% change). Patient demographics, imaging data, stone properties, and treatment outcomes were comprehensively evaluated. The evaluation of postoperative complications was performed using the Clavien-Dindo classification.

The mean patient age was 53.4 years. The mean stone size was 11.4 mm. Renal pelvis, upper, and middle calyces, and lower pole stones were found in 12.9% (13), 28.7% (29), and 34.7% (35) of cases, respectively. Single- and second-session SFRs were 95% and 99%, respectively. A third auxiliary procedure was needed in one renal unit (1%). The mean number of procedures per renal unit was 1.06 (107/101). The mean renal function pre and post-operatively was 47.3% and 48%, respectively. The majority of patients (94.1%) had unchanged renal function. However, three female patients (3%) had a decline in differential renal function (>10%) while three patients (two males and one female) (3%) had an improvement (>10%). A re-intervention was necessary in one patient, interestingly not among those with declined renal function.

Flexible ureteroscopy due to renal or ureteral stones has minimal to no impact on renal function. Renal scans pre- and post-operatively may be used in potentially high-risk patients.