Prospective Evaluation of CT Parameters as a Predictive Value of Impacted Stone and Ureteric Stricture Post Ureteroscopy

Abstract

Impacted ureteric stones present significant challenges in urological procedures, often leading to complications such as ureteral strictures. This prospective cohort study aimed to evaluate preoperative CT parameters as predictors of stone impaction and ureteric stricture formation for patient undergoing elective primary ureteroscopy, focusing on ureteral wall thickness (UWT) and the Hounsfield Unit Attenuation Ratio (HAB ratio) in non-contrasted CT imaging. A total of 24 patients with ureteric stones (18 impacted, 6 non-impacted) underwent primary ureteroscopic lithotripsy (URSL) between August 2023 and August 2024. Results indicated that impacted stones were associated with significantly higher UWT (2.79 mm vs. 1.97 mm, p = 0.021) and more severe hydronephrosis (p < 0.001). ROC curve analysis revealed that UWT and hydronephrosis had strong predictive value for stone impaction, with UWT demonstrating an area under the curve (AUC) of 0.824 at a threshold of 2.69 mm. Although the HAB ratio and stone density were not significant predictors, the combined use of UWT and hydronephrosis improved diagnostic accuracy for impacted stones. Postoperative follow-up identified a 16.7% incidence of ureteric strictures, all associated with impacted stones. These findings suggest that preoperative assessment of UWT and hydronephrosis can enhance prediction of stone impaction and guide choice of treatment modality when deciding between extracorporeal shockwave therapy (ESWL) and primary URSL based on CT parameters.