Impact of COVID-19 on Ureteroscopy Management of Urolithiasis: Retrospective Comparative Study Before and After Pandemic

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This study demonstrates how flexible surgical scheduling can ensure safe stone treatment during healthcare crises.

Abstract

The COVID-19 pandemic disrupted healthcare delivery worldwide, potentially impacting the management of urolithiasis. This study aimed to evaluate changes in referral patterns, perioperative care, and surgical outcomes among patients undergoing ureteroscopic treatment for upper ureteral stones at a Japanese institution. A retrospective cohort of 467 patients who underwent ureteroscopic lithotripsy or retrograde intrarenal surgery between March 2018 and May 2022 was analyzed. The patients were divided into pre-pandemic (March 2018–March 2020, n = 244) and post-pandemic (April 2020–May 2022, n = 223) groups. Clinical characteristics and outcomes were compared. Baseline demographics were similar. After the pandemic onset, preoperative ureteral stenting increased (30.3% vs. 42.6%, p = 0.006), while surgical waiting times (36 days vs. 28 days, p = 0.005) and operative durations (77 min vs. 67 min, p = 0.018) decreased. Referral sources shifted (p = 0.045), with fewer primary care referrals and more from emergency or higher-level hospitals. Stone-free rates (65.6% vs. 58.7%, p = 0.128) and postoperative complication rates were comparable. Despite systemic constraints during the pandemic, timely adaptations in scheduling and perioperative management allowed for the continued delivery of safe and effective ureteroscopic treatment. These findings emphasize the importance of flexible clinical strategies during healthcare crises.

1. Introduction

The emergence of the COVID-19 pandemic in early 2020 posed unprecedented challenges to healthcare systems worldwide. It disrupted medical infrastructure, necessitated rapid adaptations in healthcare delivery, and significantly altered patient behavior [1]. During the initial phase, many hospitals prioritized COVID-19 care, leading to the deferral of non-urgent surgical procedures, including those in urology [2]. Nevertheless, timely intervention for urological emergencies, such as urinary stone disease, remained critical to avoid serious complications [3]. Pandemic-related restrictions and public fear of infection contributed to delayed healthcare-seeking behavior and, in some reports, more severe clinical presentations at admission [4]. Additionally, extended home confinement and lifestyle changes, such as reduced physical activity and increased weight gain, were suggested to elevate the risk of stone formation [2].

In contrast to the strict lockdowns imposed in many countries, Japan adopted a unique approach, issuing non-mandatory emergency declarations that encouraged voluntary behavioral restrictions while maintaining public access to healthcare. Most medical facilities remained open, offering a distinctive setting in which to evaluate the pandemic’s effects on urolithiasis care.

This study aimed to investigate the impact of the COVID-19 pandemic on emergency urolithiasis management at a single Japanese institution, focusing on changes in clinical presentation, treatment decisions, and ureteroscopic outcomes before and after the onset of the pandemic. Our goal was to clarify the clinical consequences of the pandemic and identify strategies to sustain essential urological services during future healthcare disruptions.

2. Materials and Methods

2.1. Study Design and Population

This retrospective cohort study was conducted at Toho University Sakura Medical Center, a high-volume regional referral center specializing in the management of urinary tract stones and infections. The study included all 467 patients diagnosed with upper ureteral stones who underwent ureteroscopic procedures, either ureteroscopic lithotripsy (UL) or retrograde intrarenal surgery (RIRS), for upper tract urolithiasis management between March 2018 and May 2022. The study period was divided into two phases: the pre-pandemic group (March 2018 to March 2020, n = 244) and the post-pandemic group (April 2020 to May 2022, n = 223) (Figure 1). The cutoff date of April 2020 corresponds to the issuance of Japan’s first state of emergency in response to the COVID-19 pandemic.

Throughout the study period, no modifications or upgrades were made to the surgical equipment, instruments, or devices used for UL and RIRS, thereby ensuring methodological consistency and comparability between the two groups.

2.2. Data Collection

Patient data were systematically extracted from electronic medical records and included demographic and clinical characteristics, preoperative and perioperative variables, surgical parameters, clinical outcomes, and referral sources. Demographic and clinical information comprised age, sex, body mass index (BMI), Eastern Cooperative Oncology Group performance status (ECOG-PS), and medical histories such as prior urolithiasis, diabetes mellitus, and hyperparathyroidism. The use of anticoagulant/antiplatelet agents and corticosteroid was also recorded. Clinical characteristics of upper ureteral stones, including maximum stone size, laterality, and the presence of ipsilateral renal stones, were documented.

Perioperative parameters included preoperative systemic inflammatory response syndrome (SIRS), preoperative ureteral stenting status, duration of hospital stay, surgical waiting time, defined as the interval between the surgical decision and the date of the procedure, operative time, and postoperative fever. Postoperative outcomes included postoperative complications, such as fever and postoperative SIRS, and stone-free status. SIRS was defined based on the presence of at least two of the following four criteria: (1) abnormal body temperature (>38 °C or <36 °C); (2) tachycardia (heart rate > 90 bpm); (3) respiratory abnormality (respiratory rate > 20 breaths/min or PaCO₂ < 32 Torr); and (4) abnormal white blood cell count (>12,000/mm³, <4000/mm³, or >10% immature neutrophils or band forms). Postoperative stone-free status was assessed by Computed Tomography imaging and/or X-ray performed within 1.5 months following surgery. Stone-free status was defined as the absence of any residual fragments ≥ 5 mm.

Referral pathways were categorized as follows: direct presentation to our institution’s emergency department, referrals from primary care clinics, referrals from secondary or tertiary care hospitals, and other sources.

2.3. Statistical Analysis

Patients were stratified into two groups based on whether their treatment occurred before or after the onset of the COVID-19 pandemic. Descriptive statistics were used to summarize baseline characteristics, healthcare access patterns, and clinical outcomes. The Shapiro–Wilk test was employed to assess the normality of continuous variables. Continuous data were expressed as medians with interquartile ranges (IQRs), and were compared using Student’s t-test or the Mann–Whitney U test, as appropriate. Categorical variables were expressed as frequencies and percentages, and were compared using the χ²-test or Fisher’s exact test. A p value < 0.05 was considered statistically significant. All statistical analyses were performed using JMP^® Pro version 16.0 (SAS Institute Inc., Cary, NC, USA) and SPSS Statistics version 23 (IBM, Chicago, IL, USA).

2.4. Ethical Considerations

This study was approved by the Ethics Committee of Toho University Sakura Medical Center (Approval No. S24084_S23020). Owing to the retrospective nature of this study, the requirement for informed consent was waived in accordance with institutional and ethical guidelines. This study was publicly disclosed on the institutional website, allowing potential participants the opportunity to opt out. All procedures were conducted in accordance with the ethical principles of the Declaration of Helsinki.

3. Results

3.1. Patient Demographics and Clinical Characteristics

A total of 467 patients who underwent UL or RIRS for upper ureteral stones between March 2018 and May 2022 were included in the analysis. Among them, 244 patients received treatment during the pre-pandemic period (March 2018–March 2020), and 223 during the post-pandemic period (April 2020–May 2022) (

Table 1. Baseline characteristics of the study population.

Variables	Total (N = 467)
Sex (Male/Female), n (%)	303 (64.9)/164 (35.1)
Age (years), median (IQR)	61 (21.0)
BMI (kg/m2), median (IQR)	24.5 (5.5)
ECOG-PS ≥ 2, n (%)	14 (3.0)
Medical history, n (%)
Prior urolithiasis	269 (57.6)
Diabetes mellitus	94 (20.1)
Hyperparathyroidism	12 (2.6)
Medication use, n (%)
Anticoagulant/antiplatelet agents	33 (7.1)
Corticosteroid, n (%)	13 (2.8)
Upper ureteral stones:
Max stone size (mm), median (IQR)	11.9 (10.5)
Laterality (right/left/bilateral)	211 (49.2)/230 (45.2)/26 (5.6)
Renal stones, n (%)	88 (18.8)
Preoperative SIRS, n (%)	63 (13.5)
Preoperative stenting, n (%)	169 (36.2)
Hospital stay (days), median (IQR)	5 (2)
Surgical waiting day (days), median (IQR)	33 (29)
Operative time (min), median (IQR)	70 (49)
Postoperative fever, n (%)	32 (6.9)
Postoperative SIRS, n (%)	27 (5.8)
Stone free rates, n (%)	291 (62.3)
Referral patterns:
Emergency department at our institution, n (%)	82 (18)
From primary care clinics, n (%)	157 (34)
From secondary/tertiary care hospitals, n (%)	112 (24)
Others, n (%)	116 (18)

BMI: body mass index, ECOG-PS: Eastern Cooperative Oncology Group-Performance Status, IQR: interquartile range, Max: maximum, min: minutes, SIRS: systematic inflammatory response syndrome.

and

Table 2. Comparative analysis before and after the COVID-19 pandemic.

Variables N = 467	Before the COVID-19 n = 244	After the COVID-19 n = 223	p Value
Sex (Female), n (%)	83 (34.0)	81 (36.3)	0.602
Age (years), median (IQR)	61 (19.0)	60 (22.0)	0.442
BMI (kg/m2), median (IQR)	24.5 (6.5)	24.5 (4.7)	0.200
ECOG-PS ≥2, n (%)	4 (1.6)	10 (4.5)	0.072
Medical history, n (%)
Prior urolithiasis	151 (61.9)	118 (52.9)	0.062
Diabetes mellitus	46 (18.9)	48 (21.5)	0.472
Hyperparathyroidism	4 (1.6)	8 (3.6)	0.300
Medication use, n (%)
Anticoagulant/antiplatelet agents	18 (7.4)	15 (6.7)	0.784
Corticosteroid	5 (2.0)	8 (3.6)	0.467
Upper ureteral stones:
Max stone size (mm), median (IQR)	12.0 (11.8)	11.9 (10.2)	0.073
Renal stones, n (%)	50 (20.5)	38 (17.0)	0.34
Preoperative SIRS, n (%)	29 (11.9)	34 (15.3)	0.288
Preoperative stenting, n (%)	74 (30.3)	95 (42.6)	0.006
Hospital stay (days), median (IQR)	5 (3.0)	5 (1.0)	0.032
Surgical waiting day (days), median (IQR)	36 (30)	28 (28)	0.005
Operative times (min), median (IQR)	77 (51.8)	67 (43.0)	0.018
Postoperative fever, n (%)	19 (7.8)	13 (5.8)	0.403
Postoperative SIRS, n (%)	15 (6.2)	12 (5.4)	0.723
Stone free rates, n (%)	160 (65.6)	131 (58.7)	0.128
Referral patterns:			0.045
Emergency department at our institution, n (%)	37 (15)	45 (20)
From primary care clinics, n (%)	96 (39)	61 (27)
From secondary/tertiary care hospitals, n (%)	53 (22)	59 (27)
Others, n (%)	58 (24)	58 (26)

BMI: body mass index, ECOG-PS: Eastern Cooperative Oncology Group-Performance Status, IQR: interquartile range, Max: maximum, min: minutes, SIRS: systematic inflammatory response syndrome.

).

The median age of the overall cohort was 61 years (IQR: 21.0), with no statistically significant difference observed between the pre-pandemic and post-pandemic groups (61 vs. 60 years, p = 0.442). Females accounted for 35.1% of the total population, with comparable distributions in both groups (p = 0.602). The median BMI was 24.5 kg/m² (IQR: 5.5), showing no significant intergroup variation (p = 0.200). Medical histories, including diabetes mellitus (18.9% vs. 21.5%, p = 0.472) and hyperparathyroidism (1.6% vs. 3.6%, p = 0.300), were similar between the two cohorts. Likewise, the proportion of patients on anticoagulant/antiplatelet therapy (7.4% vs. 6.7%, p = 0.784) and corticosteroid use (2.0% vs. 3.6%, p = 0.467) remained comparable.

A statistically significant shift in referral pathways was observed between the two periods (p = 0.045). As illustrated in Figure 2, referrals from primary care clinics declined from 39% to 27%, whereas referrals from emergency departments (15% to 20%) and secondary/tertiary-care hospitals (22% to 27%) increased.

3.2. Perioperative Parameters

Preoperative SIRS was identified in 13.5% of the total cohort, with no significant difference between the pre-pandemic (11.9%) and post-pandemic (15.3%) groups (p = 0.288). The prevalence of preoperative ureteral stenting increased significantly in the post-pandemic period, rising from 30.3% to 42.6% (p = 0.006). Stone-related variables, including maximum stone size (12.0 mm vs. 11.9 mm, p = 0.073) and the presence of renal stones (20.5% vs. 17.0%, p = 0.340), did not differ significantly between groups.

A significant reduction in operative time was observed in the post-pandemic cohort (77 min vs. 67 min, p = 0.018). Surgical waiting time also decreased from a median of 36 days to 28 days (p = 0.005). The median hospital stay was 5 days (IQR: 2) in both groups, with an initially significant difference in mean duration (6.7 [±5.4] vs. 9.7 [±20.8] days, p = 0.032). However, when two extreme outliers with prolonged hospitalization (148 and 263 days) in the post-pandemic group, both of which were prolonged due to unrelated comorbid conditions, were excluded, the difference was no longer statistically significant.

3.3. Treatment Outcomes and Complications

The overall stone-free rate was 62.3%, with no statistically significant difference between the pre-pandemic (65.6%) and post-pandemic (58.7%) groups (p = 0.128). Postoperative complication rates remained stable, including the incidence of fever (7.8% vs. 5.8%, p = 0.403) and postoperative SIRS (6.2% vs. 5.4%, p = 0.723), with no meaningful differences noted between the two time periods.

This bar graph illustrates the distribution of referral sources for ureteroscopic stone cases in the pre-pandemic period (March 2018–March 2020) compared to the post-pandemic period (April 2020–May 2022). Notably, the proportion of patients referred from primary care clinics decreased in the post-COVID era (reflecting fewer elective referrals), while referrals from emergency departments and secondary/tertiary hospitals increased.

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, Kachroo 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. Ansari Jafari et al. found patients avoided healthcare facilities unless necessary [7], and Jiang 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. Romantini et al. detailed a case of bilateral ureteral obstruction requiring urgent dialysis [9], while Silva et al. reported longer hospital stays among obstructive pyelonephritis 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 Gul 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. Jones et al. and Leventhal et al. reported a 55–60% decline in primary care visits and a rapid shift to telemedicine, affecting referral flow [12,13,14]. Mazzon 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. This transition may reflect both modified health-seeking behaviors and structural changes in outpatient access during the pandemic.

The increase in preoperative stenting and the reduction in waiting times observed in our study reflect a successful institutional adaptation to the pandemic. This bridging strategy enabled symptom control while facilitating flexible scheduling amid constrained resources [1]. The five-tier urgency classification system proposed by Cleveland Clinic, categorizing infected or obstructing stones as Tier 0 (highest urgency), provided a useful framework for procedural triage [15]. Our approach aligns with recommendations from both international and domestic guidelines, including those by the European Association of Urology Rapid Reaction Group [16] and the Japanese Urological Association [17], which endorse preoperative stenting as a valid interim measure. Since stone size did not differ significantly between groups (Table 2), shorter operative times in the post-pandemic cohort may be largely due to the increased use of preoperative stenting.

Numerous studies support the benefits of preoperative stenting. Yang et al. conducted a meta-analysis demonstrating that double-J stenting significantly improves stone-free rates (odds ratio 1.60, 95% confidence interval [CI] 1.19–2.15, p = 0.002) [18]. Law et al. reported that stenting enhances access sheath insertion success (risk ratio 1.09, 95% CI 1.05–1.13, p < 0.00001) and reduces ureteral injury risk [19]. Chen and Ren introduced a triage framework based on disease severity [20], and Yuk et al. demonstrated improved-access sheath success rates with stenting (93.8% vs. 85.3%, p = 0.023) [21]. Lumma et al. further reported higher stone-free rates and lower complication rates among pre-stented patients, especially for proximal ureteral and renal pelvis stones [22]. This is consistent with Yasseri et al.’s emphasis on temporizing strategies such as stents and nephrostomy in maintaining essential services [2]. Yildiz et al. further supported the role of passive dilation in procedural success [23]. A salient finding of this study is that clinical outcomes remained stable, or even improved, despite the operational challenges posed by the pandemic. In our cohort, the number of presenting cases increased during the COVID-19 period. The observed reductions in operative time, while maintaining stone-free and complication rates, underscore the efficacy of adaptive clinical strategies.

While a non-significant increase in patients with ECOG-PS ≥2 was noted post-pandemic, emergency urolithiasis care remained a clinical priority, in contrast to elective cases which may have been deferred. Our observations mirror institutional experiences at Cleveland Clinic, where in-person visits fell from 100% to 6%, replaced by virtual consultations, and delays in clinic visits increased from 7 days to 15 days (p < 0.0001) [6]. Moreover, shifts in postoperative stent management were reported, with a marked increase in stentless procedures (12% to 66%) and the use of extraction strings for self-removal (7% to 16%) [6].

A global review by Militaru et al. described a 34% decline in elective urologic surgeries and a 9.3% decrease in emergency procedures during the pandemic [24]. This led to innovations such as increased use of stents with strings and stentless techniques [24]. The shortened surgical waiting time observed in our study likely contributed to maintaining favorable outcomes, even with higher stenting rates. Nevo et al. demonstrated that prolonged stent indwelling times increase the risk of post-ureteroscopy sepsis (1% for <1 month vs. 9.2% for >3 months) [25]. Additionally, Joshi et al. showed that long-term stents can substantially impair quality of life [26]. Our institution minimized stent duration, ensuring timely definitive surgery. Previous studies by Chu et al. and Rubenstein et al. further confirm that preoperative stenting is associated with reduced operative time and improved stone-free rates, which supports our observations during the pandemic [27,28].

This study has several limitations. First, it was conducted at a single center with a retrospective design, which may introduce selection bias and limit the ability to control for unmeasured confounding factors. Second, the analysis included only patients undergoing ureteroscopic procedures (UL or RIRS), limiting generalizability to those treated with alternative modalities such as extracorporeal shock wave lithotripsy or percutaneous nephrolithotomy. Third, long-term outcomes and patient-reported measures, including quality of life, were not evaluated. Given its retrospective nature, causality cannot be established, and the findings should be interpreted with caution. Despite these limitations, our findings provide valuable insights that may inform strategies to sustain essential endourological services during future healthcare system disruptions.

5. Conclusions

In conclusion, despite the operational challenges imposed by the COVID-19 pandemic, the implementation of timely and flexible surgical strategies enabled the continued delivery of high-quality urolithiasis care. These findings underscore the resilience of surgical pathways and highlight the importance of developing adaptable perioperative protocols to ensure uninterrupted urolithiasis care during future healthcare crises.