Secondary signs of non-enhanced CT prior to laser ureterolithotripsy: is treatment outcome predictable?

Abstract

Purpose: To correlate the presence of secondary signs of non-enhanced computed tomography (NECT) in renal units harboring ureteral calculi with intraoperative findings and treatment outcome after holmium:yttrium-aluminum-garnet laser (Ho:YAG) ureterolithotripsy.

Subjects and methods: Two-hundred patients were prospectively included after ureteral calculi were detected on NECT. All patients underwent Ho:YAG ureterolithotripsy at the Medical University of Vienna. All CT studies were reviewed by one specialized uroradiologist blinded to pre- and postoperative parameters for secondary signs as renal enlargement, perinephric stranding, ureteral dilation, periureteral edema, and ureteral rim sign. The impact of secondary signs on intraoperatively-verified impaction and treatment outcome was evaluated.

Results: Of the 200 patients 85 (42.5%) harbored proximal and 115 (57.5%) harbored distal ureteral calculi. The stone-free rates for proximal and distal calculi were 80% and 97%, respectively. Although proximal stone location and intraoperatively-verified impaction correlated significantly with stone-free rates (P < 0.0001, P = 0.01), the presence of secondary signs could not predict intraoperatively-verified stone impaction or stone-free rates (renal enlargement: P = 0.2, P = 0.5; perinephric stranding: P = 0.7, P = 0.5; ureteral dilation: P = 0.7, P = 0.7; periureteral edema: P = 0.8, P = 0.06; ureteral rim sign: P = 0.8, P = 0.3).

Conclusion: Preoperative secondary signs seen on NECT in patients harboring ureteral calculi do not correlate with intraoperative findings of impaction, and do not predict treatment outcome after Ho:YAG ureterolithotripsy.