Assistant Professor Nagoya city University graduate school of Medical Sciences
Introduction: Difficulty performing ureteroscopic lithotripsy (URSL) depends on endoscopic findings (EFs) surrounding calculi. We established a classification of EFs and analyzed the risk factors for ureteral changes.
Methods: This was a multicenter prospective cohort study of 832 patients who underwent ureteroscopic lithotripsy registered in the SMART Study Group from January 2014 to February 2017; 185 cases of single ureteral stones were analyzed. We evaluated EFs (edema, polyps, stone adhesion, and distal ureteric tightness) based on the SMART classification (Figure1).
Results: Surgical duration and ureteral damage during URSL were significantly correlated with EFs grade. Multivariate analysis revealed that edema was affected by stone size (odds ratio, 9.50; p<0.001), and stone adhesion was strongly affected by hydronephrosis grade (odds ratio, 12.4; p=0.022) and the interval before surgery (odds ratio, 1.10; p=0.012) (Table 1). The cutoff value for stone adhesion was 98 days, with a predictive accuracy of 0.78. The risk factors for distal ureteric tightness were age (odds ratio, 0.96; p=0.004) and early intervention (odds ratio, 0.90; p=0.023). The cutoff value was 34 days, with a predictive accuracy of 0.72.
Conclusions: We first defined UFs during URSL and used the SMART classification to predict surgical difficulty worldwide. Retention time of a ureteral stone and the presence of hydronephrosis were risk factors for stone adhesion. There is a relationship between early intervention and patient age with DUT. URSL should be performed as soon as possible within one month of symptom onset. However, for suspected stone impaction cases with more than 3 months until symptom onset, alternative procedures and detailed informed consent should be planned in advance. Source of
