## 4 Discussion  
In this study, assessing the impact of the COVID-19 pandemic on emergency urolithiasis management, three principal findings were identified. First, the rate of preoperative ureteral stenting significantly increased during the pandemic period (30.3% vs. 42.6%, \(p\) = 0.006), accompanied by a notable reduction in surgical waiting time (36 days vs. 28 days, \(p\) = 0.005). This trend suggests that preoperative stenting may have facilitated more efficient surgical scheduling amidst resource limitations. Second, despite pandemic-related constraints, operative times were significantly reduced (77 min vs. 67 min, \(p\) = 0.018) while maintaining comparable clinical outcomes, including stone-free and complication rates. Although there was a non-significant trend toward a lower stone-free rate post-pandemic (\(p\) = 0.128), overall treatment efficacy remained consistent. Third, there was no significant increase in the incidence of preoperative SIRS (11.9% vs. 15.3%, \(p\) = 0.288) and max stone size (12.0 mm vs. 11.9 mm, \(p\) = 0.073), and emergency department consultation rates remained stable between periods. These results suggest that disease severity did not worsen and that emergency urological care remained accessible during the pandemic. Globally, the COVID-19 pandemic resulted in a substantial decline in emergency presentations for upper ureteral stones. A multicenter Italian study reported a 51% reduction in emergency department visits for symptomatic ureteral stones during the March-April 2020 lockdown (78 cases vs. 160 cases) [5]. Similarly, [PERSON] et al. at Cleveland Clinic observed a 36% decrease in stone-related emergency visits [6]. In contrast, our study showed stable emergency department utilization, but a significant shift in referral patterns (\(p\) = 0.045), with fewer referrals from primary care clinics (39% to 27%) and more from tertiary hospitals and emergency departments. This may reflect the absence of legal restrictions on emergency access in Japan, unlike many countries with strict lockdowns. Public fear also played a role. [PERSON] et al. found patients avoided healthcare facilities unless necessary [7], and [PERSON] et al. noted heightened anxiety and avoidance of in-person care during the pandemic [8]. This universal fear of infection likely contributed to reduced referrals from primary care clinics, as observed in our cohort. Several reports described worsening clinical conditions due to delayed care. [PERSON] et al. detailed a case of bilateral ureteral obstruction requiring urgent dialysis [9], while [PERSON] et al. reported longer hospital stays among obstructive pyclonephritis cases during the pandemic (mean 7.6 days vs. 3.8 days) [10]. Although our study also found a trend toward longer hospital stays, the difference was not statistically significant after excluding cases with unusually prolonged stays due to unrelated complications. While [PERSON] et al. observed significantly elevated serum creatinine and white blood cell counts during the pandemic [11], our study did not find a corresponding increase in preoperative SIRS, possibly reflecting more stable access to emergency services in Japan. This pattern extended to primary care and elective surgeries. [PERSON] et al. and [PERSON] et al. reported a 55-60% decline in primary care visits and a rapid shift to telemedicine, affecting referral flow [12; 13; 14]. [PERSON] et al. found a 29.2% reduction in surgical volume during lockdowns and 7.9% post-lockdown, with stable stone-free and complication rates [4]. While our study likewise identified a decline in consultations originating from primary care clinics, the overall number of patients and surgical procedures did not exhibit a statistically significant reduction. Notably, the shift in referral patterns illustrated in Figure 2 reveals a diminished reliance on primary care-based referrals and a corresponding increase in presentations via emergency or hospital-based pathways.