Prospective observational study on the prognosis of ureteral lesions caused by impacted stones via dual-energy spectral computed tomography

Objective

Ureteral lesions caused by impacted ureteral stones are likely to result in postoperative ureteral stricture. On this basis, the study aimed to investigate if dual-energy spectral computed tomography can predict ureteral hardening caused by impacted stones and to explore the relationship between different types of ureteral lesions and the risk of ureteral stricture.

Methods

This prospective study collected data of 93 patients with impacted stones from hospital automation system during January 2018 to October 2019. They underwent an abdominal scan on a dual-energy spectral computed tomography. During surgery, the operator used ureteroscopy to identify ureteral lesions, which were classified into four categories: edema, polyps, pallor, and hardening. Seven months later, 90 patients were reviewed for the degree of hydronephrosis.

Results

Endoscopic observations revealed 38 (41%) cases of ureteral edema, 20 (22%) cases of polyps, 13 (14%) cases of pallor, and 22 (24%) cases of hardening. There were significant differences in hydronephrosis, the period of impaction, the calcium concentration of the ureter, and the slope of the spectral Hounsfield unit curve between the four groups. After that, we evaluated the factors associated with ureteral hardening and found that the calcium concentration of the ureter and hydronephrosis remained independent predictors of ureteral hardening. Receiver operating characteristic curve analysis showed that 5.3 mg/cm³ calcium concentration of the ureter is an optimal cut-off value to predict ureteral hardening. The result of follow-up showed that 80 patients had complete remission of hydronephrosis, with a complete remission rate of 61.9% (13/21) in the hardening group and 97.1% (67/69) in the non-hardening group (p<0.001).

Conclusion

Calcium concentration of the ureter is an independent predictor of ureteral hardening. Patients with ureteral hardening have more severe hydronephrosis after ureteroscopic lithotripsy. When the calcium concentration of the ureter is less than 5.3 mg/cm³, ureteral lesions should be actively treated.