Predictive factors for prolonged operative time in ureteroscopic lithotripsy for ureteral stones

Introduction: A prolonged operative time of lithotripsy with ureteroscopy for urolithiasis increases the risk of infectious complications; however, few reports have investigated the factors prolonging the operative time for ureteral stones. We investigated the factors associated with longer operative time in ureteroscopy for ureteral stones. Methods: This retrospective cohort study analyzed patients who underwent retrograde ureteroscopic lithotripsy for ureteral stones and achieved an endoscopic stone-free status between April 2019 and July 2022. Patients were classified into two groups based on an operative time of ≥90 minutes or <90 minutes. We compared the patient and stone characteristics and surgical outcomes, and investigated the factors associated with a prolonged operative time. Results: The cohort comprised 519 patients, with 58 patients in the group with an operative time of ≥90 minutes. Compared to the shorter operative time group, the longer operative time group had a significantly greater proportion of males, stone diameter, stone volume, and Hounsfield units of stone; additionally, the longer operative time group had higher prevalences of endoscopic findings of edema, polyps, and mucosa-stone adherence. Multivariable analysis showed that stone size >10 mm (odds ratio 4.05), polyps (odds ratio 2.40), and mucosal adherence (odds ratio 3.51) were significantly associated with an operative time exceeding 90 minutes. There were no significant differences between the two groups in the incidences of postoperative fever and systemic inflammatory response syndrome. Conclusions: Stone size, endoscopic findings of polyps, and mucosa-stone adherence were independent factors associated with a longer operative time.