Changes in intrarenal vascular indices after semi-rigid ureteroscopy in pediatric urolithiasis

We evaluated preoperative and postoperative intrarenal vascular parameters, including resistive index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end-diastolic velocity (EDV). Furthermore, we assessed postoperative changes in these indices (ΔRI, ΔPI, ΔPSV, ΔEDV) after semi-rigid ureteroscopy (URS), compared them with contralateral normal kidneys, and identified potential factors influencing variations in renal vascular resistance.

A prospective analysis was conducted on 23 pediatric patients who underwent semi-rigid URS. Preoperative grayscale ultrasonography and color Doppler ultrasonography (CDUS) were performed precisely 24 h prior to surgery and exactly 24 h following the procedure. The grade of hydronephrosis, stone location in the obstructed kidneys, renal dimensions, and parenchymal thickness were assessed using grayscale US. Subsequently, CDUS was used to calculate intrarenal RI, PI, PSV, and EDV values for each kidney.

In the operated kidneys, statistically significant increases were observed in RI, PI, and PSV values (p < 0.001). Increases in RI, PI, and PSV (ΔRI, ΔPI, ΔPSV) were also significantly higher compared with those in the non-operated kidneys (p < 0.05). Spearman correlation analysis demonstrated that ΔRI, ΔPI, and ΔPSV were associated with operative time and irrigation fluid volume. However, no significant correlations were found with age, gender, ureteroscopy side, stone location, or degree of hydronephrosis.

Significant but short-term hemodynamic alterations in RI, PI, and PSV observed in children undergoing semi-rigid URS indicate that the procedure leads to a substantial but transient increase in renal vascular resistance. Moreover, prolonged operative duration and higher irrigation fluid volume were strongly associated with increased ΔRI, ΔPI, and ΔPSV.