Japanese survey of perioperative complications and ureteral stricture after ureteroscopy with laser lithotripsy for upper urinary tract stones in multicenter collaborative study.

OBJECTIVES: This study aimed to investigate perioperative complications and the details of postoperative ureteral stricture after ureteroscopy with laser lithotripsy (URS-L) for upper urinary tract stones in Japan. METHODS: Patient data on intra- and postoperative complications after ureteroscopy using URS-L were retrospectively collected from multiple centers in Japan between April 2017 and March 2020 with the cooperation of the Japanese Society of Endourology and Robotics. Data included the number of patients undergoing URS-L, number and type of intra- and postoperative complications, and detailed characteristics of postoperative ureteral stricture. RESULTS: In total, 14 125 patients underwent URS-L over 3 years at 82 institutions. Annual URS-L numbers gradually increased from 4419 in 2017, to 4760 in 2018, and 4946 in 2019. The total complication rate was 10.5%, which was divided into intra-operative complications in 1.40% and postoperative complications in 9.18%. The annual incidences of intra- and postoperative complications were not significantly different from year to year (p = 0.314 and p = 0.112). Ureteral perforation, ureteral avulsion, and the intra-operative conversion rate were 1.35%, 0.03%, and 0.02%, respectively. Fever >38°C, septic shock, blood transfusion, and postoperative mortality were 7.44%, 0.81%, 0.07%, and 0.04%, respectively. Ureteral stricture occurred in 0.8% of cases. The median length of stricture site was 10.0 mm and the success rate of stricture treatment was 54.6%. CONCLUSION: Although URS-L utilization has increased in Japan, the annual complication rate has remained steady. Although URS-L is a useful and less invasive procedure, devastating complications can still occur.

Impact of diagnostic ureteral catheterization on intravesical tumour recurrence following radical nephroureterectomy for upper tract urothelial carcinoma.

PURPOSE: To investigate whether even a minimally invasive diagnostic procedure for the upper tract such as ureteral catheterization (UCath) may substantially increase the risk of intravesical recurrence (IVR) in patients with upper tract urothelial carcinoma (UTUC) treated with radical nephroureterectomy (RNU). METHODS: The present, retrospective study enrolled 163 patients undergoing RNU for UTUC between 2010 and 2021 at two, tertiary care hospitals. The primary endpoint was the association between UCath and IVR-free survival (IVRFS). The secondary endpoints were the association of ureterorenoscopy (URS) and URS biopsy (URSBx) with IVRFS. Directed acyclic graph (DAG)-guided multivariable models were used to adjust for potential confounders. RESULTS: Of the 163 patients, 128 (79%), 88 (54%), and 67 (41%) received UCath, URS, and URSBx, respectively. URS was performed concurrently with UCath. During the follow-up period (median: 47 months), IVR developed in 62 patients (5-year IVRFS rate: 52%). A DAG included concurrent bladder cancer, tumour size, hydronephrosis, positive cytology, and multiple UTUCs as potential confounders of the association between UCath and IVR. Both DAG-guided and stepwise multivariable models revealed a significant association between UCath and IVR (hazard ratio: 17.8; P < 0.001). UCath was also associated with shorter IVRFS in a subset of 75 patients who had not received URS (P < 0.001). In contrast, URS and URSBx were not associated with IVR in patients who had received UCath and URS, respectively. CONCLUSION: Any diagnostic manipulations of the upper urinary tract, even a minimally invasive procedure like UCath, could confer a risk of post-RNU IVR in UTUC patients.

Stone-event-free survival after ureteroscopic lithotripsy by age: comparison between young and older patients.

The aim of this study is to examine stone-event-free survival after ureteroscopic lithotripsy (URSL) and risk factors for stone events by age. We retrospectively collected data of all URSL cases at our institution from 2008 to 2021. A total of 1334 cases were included and divided into young (< 65 years, 792 cases), young-old (65-74 years, 316 cases), old-old (75-84 years, 172 cases), and oldest-old (≥ 85 years, 54 cases) groups. Patient characteristics, surgical outcomes, and postoperative stone events were evaluated. The stone-event-free survival and risk factors were compared between young and older groups. Overall, 214 (16.0%) cases developed stone events during a mean follow-up period of 763 days and the 2-year, 5-year, and 8-year stone-event-free survival rates were 84.5%, 72.2%, and 57.2%, respectively. The numbers of stone events in young, young-old, old-old, oldest-old groups were 133 (16.8%), 53 (16.8%), 21 (12.2%), and 7 (13.0%), respectively. No significant differences were found in stone-event-free survival between the young group and each of the older groups. Residual fragment > 4 mm and stone burden ≥ 15 mm were common risk factors in both young and older groups. Especially in older patients, preoperative stenting, which was most often performed to treat obstructive pyelonephritis, was the third risk factor. In conclusion, stone-event-free survival after URSL was comparable between young and older patients. Residual fragment > 4 mm and stone burden ≥ 15 mm were common risk factors in both groups. Preoperative stenting was an additional risk factor in older patients, suggesting that urinary tract infection may influence stone events.

[A Case Report of Metachronous Multiple Cancers Including Triple Lung Cancers, Gastric Cancer, and Double Urothelial Cancers].

A male patient in his 60s at the time of the first medical examination had a smoking history of 50 years with 25 cigarettes a day. He was diagnosed with double urothelial cancers. In 200a, total left pelvic ureterectomy(pT2N0M0, Stage Ⅱ)and transurethral bladder tumorectomy(pTisN0M0, Stage Ⅰ)were performed. For his gastric cancer with malignant pleural effusion(cT3N0M1, Stage Ⅳb), in 200a plus 2, downstaging was acquired after chemotherapy. In 200a plus 5, subtotal gastrectomy D1 dissection was performed(W/D adenocarcinoma, pT2N0M0, Stage ⅠA, Ef 1). For the first lung cancer, in 200a plus 5, thoracoscopic lung wedge resection of the left lower lobe was performed(P/D adenocarcinoma, pT1aN0M0, Stage ⅠA1, R0, Ef 1). For the second lung cancer, in 200a plus 13, thoracoscopic lung wedge resection of the right upper lobe was performed after chemotherapy(P/D adenocarcinoma, pT1bN0M0, Stage ⅠA2, R0). For the third lung cancer, in 200a plus 17, immunotherapy was performed for the left upper lobe lung cancer(P/D adenocarcinoma, cT3N1M1a, Stage ⅢA). All the cancers were diagnosed as primary lesions by immunohistological examination. For the metachronous multiple cancers, multidisciplinary treatment was necessary for each cancer considering the patient's physical condition. Moreover, strict follow-up was necessary because of the high risk of carcinogenesis.

Adverse Prognostic Impact of Diagnostic Ureterorenoscopy in a Subset of Patients with High-Risk Upper Tract Urothelial Carcinoma Treated with Radical Nephroureterectomy.

Background: We hypothesized that diagnostic ureterorenoscopy (URS) may adversely affect prognosis in a subset of patients with high-risk upper tract urothelial carcinoma (UTUC) undergoing radical nephroureterectomy (RNU). Methods: The present retrospective study included 143 patients with UTUC treated between 2010 and 2021 at two tertiary care hospitals, of whom 79 received URS prior to RNU. Subgroups were stratified by clinicopathological variables relevant to prognosis. The primary endpoint was to evaluate the prognostic impact of URS on overall survival (OS) and progression-free survival (PFS) after RNU. Results: During follow-up (median 54 months for survivors), 32 cases of all-cause mortality and 40 cases of progression were recorded. No significant difference was found in OS or PFS between patients with and without URS. Subgroup analysis demonstrated that URS was significantly associated with worse OS (p < 0.001) and PFS (p = 0.008) in 29 patients with non-papillary and ≥pT3 UTUC. Importantly, URS did not have any adverse effects on prognosis in 62 patients with papillary and ≤pT2 UTUC (p = 0.005). Conclusions: URS may adversely affect prognosis of UTUC patients, specifically non-papillary and ≥pT3 disease. URS may better be avoided in patients with high-risk UTUC features unless URS is necessary to diagnose UTUC. This study also corroborates the oncological safety of URS in those with low-risk UTUC.

Different failure rates of insertion of 10/12-Fr ureteral access sheaths during retrograde intrarenal surgery in patients with and without stones.

PURPOSE: The aim of this study was to compare the failure rates of insertion of a 10/12-Fr ureteral access sheath (UAS) during retrograde intrarenal surgery (RIRS) in cases with and without stones and to analyze the risk factors for UAS insertion failure. MATERIALS AND METHODS: A total of 640 RIRS cases (538 with and 102 without stones) were evaluated. The primary outcome of interest was the failure rate of insertion of a 10/12-Fr UAS. Associated risk factors were assessed using univariate and multivariate logistic regression analyses. Propensity score (PS) matching and inverse probability of treatment weighting (IPTW) were used to ensure the robustness of the results. RESULTS: The overall failure rate of 10/12-Fr UAS insertion in the cases without stones was significantly higher than that in the cases with stones (39.2% vs. 7.2%; p<0.001), and was approximately 2.5 to 4 times higher after PS matching and IPTW. Multivariate logistic analyses showed that being in the group without stones and younger age were independent significant risk factors for insertion failure in both the PS-matched cohort (odds ratio [OR], 5.43; 95% confidence interval [CI], 2.16-13.6; and OR, 1.04; 95% CI, 1.01-1.07) and the IPTW-adjusted cohort (OR, 1.82; 95% CI, 1.14-2.90; and OR, 1.03; 95% CI, 1.01-1.04). CONCLUSIONS: The incidence of 10/12-Fr UAS insertion failure during RIRS was higher in cases without stones than in those with stones. These results provide valuable information for surgeons to use during informed consent discussions with patients undergoing RIRS, especially patients without stones.

Risk factors and predictive model for incidence of difficult ureter during retrograde ureteroscopic lithotripsy.

OBJECTIVE: Difficult ureter can be a challenge for accessing upper urinary tract during lithotripsy. In this study, we evaluated the risk factors for the incidence of difficult ureter in retrograde ureteroscopic lithotripsy. Moreover, we aimed to develop a predictive model for the incidence of difficult ureter. METHODS: We retrospectively reviewed consecutive retrograde ureteroscopic lithotripsies performed at our institution between 2009 and 2021. A total of 1010 renal units were evaluated: 449 units with renal stones only and 561 units with ureteral stones, with or without renal stones. RESULTS: The overall incidence of difficult ureter was 5.9%, with a higher incidence in the renal alone stone group than in the ureteral stone group (7.8% vs 4.5%, P = 0.026). Multivariate regression analysis revealed three risk factors for the incidence of difficult ureter: absence of stone history (odds ratio 5.67, 95% confidence interval 2.40-13.4, and P < 0.001), age ≤45 years (odds ratio 3.61, 95% confidence interval 2.05-6.37, and P < 0.001), and renal stone only (odds ratio 2.11, 95% confidence interval 1.22-3.64, and P = 0.008). A simple model using these three risks enabled the stratification of the incidence rate of difficult ureter, with the incidence of high-risk cases being 12.7%. CONCLUSIONS: The greatest risk factor for the incidence of difficult ureter was the absence of stone history, followed by age 45 years or younger, and having only renal stones. In high-risk cases of difficult ureter, the possibility of secondary lithotripsy should be explained to the patients.

Variables measured on three-dimensional computed tomography are preferred for predicting the outcomes of shock wave lithotripsy.

PURPOSE: Shock wave lithotripsy (SWL) is used to treat upper urinary tract stones. Recently, some volume analyzers have enabled preoperative assessment using three-dimensional computed tomography (3D-CT). We evaluated the efficacy of 3D-CT variables for predicting the outcomes of SWL. METHODS: The study population included 193 patients who underwent SWL between November 2014 and August 2020. In addition to conventional two-dimensional computed tomography (2D-CT) assessments, 3D-CT assessments of targeted stones were retrospectively performed, and stone size and stone density (SD) were measured. The successful and unsuccessful treatment groups were compared and risk factors for an unsuccessful first SWL session were investigated. The predictive accuracy of variables measured on 3D-CT was evaluated by receiver operating characteristic curves and multivariate analyses. RESULTS: The success rate of the first SWL session was 73.1%. Stone volume, mean SD and highest SD on 3D-CT were significantly higher in the unsuccessful group than in the successful group. Stone volume showed a higher area under the curve (AUC) than the estimated volumetric stone burden and stone diameter, which were measured on 2D-CT (0.729, 0.683, and 0.672, respectively). The AUCs of the mean SD and highest SD on 3D-CT were higher than those on 2D-CT (0.699, 0.680, 0.617, and 0.627, respectively). Multivariate analyses identified stone volume (≥ 0.29 ml), mean SD on 3D-CT (≥ 421 HU), and absence of hydronephrosis as independent predictive factors for unsuccessful SWL. CONCLUSION: 3D-CT variables were promising predictors of the outcomes of SWL. Preoperative 3D-CT assessment is helpful for selecting favorable patients for SWL.

Prognostic Accuracy of the qSOFA Score for In-Hospital Mortality in Elderly Patients with Obstructive Acute Pyelonephritis: A Multi-Institutional Study.

Prognostic accuracy of the quick sequential organ failure assessment (qSOFA) score for mortality may be limited in elderly patients. Using our multi-institutional database, we classified obstructive acute pyelonephritis (OAPN) patients into young and elderly groups, and evaluated predictive performance of the qSOFA score for in-hospital mortality. qSOFA score ≥ 2 was an independent predictor for in-hospital mortality, as was higher age, and Charlson comorbidity index (CCI) ≥ 2. In young patients, the area under the curve (AUC) of the qSOFA score for in-hospital mortality was 0.85, whereas it was 0.61 in elderly patients. The sensitivity and specificity of qSOFA score ≥ 2 for in-hospital mortality was 80% and 80% in young patients, and 50% and 68% in elderly patients, respectively. For elderly patients, we developed the CCI-incorporated qSOFA score, which showed higher prognostic accuracy compared with the qSOFA score (AUC, 0.66 vs. 0.61, p < 0.001). Therefore, the prognostic accuracy of the qSOFA score for in-hospital mortality was high in young OAPN patients, but modest in elderly patients. Although it can work as a screening tool to determine therapeutic management in young patients, for elderly patients, the presence of comorbidities should be considered at the initial assessment.

How does pre-operative antimicrobial treatment influence the intra-operative culture results and infectious complications in patients with positive baseline bladder urine culture undergoing ureteroscopic lithotripsy?

We investigated how pre-operative antimicrobial treatment influenced intra-operative culture (IC) results and infectious complications in patients with positive pre-operative bladder urine culture (PBUC) undergoing ureteroscopic lithotripsy. We assessed 162 patients undergoing ureteroscopic lithotripsy from April 2019 to March 2020. Based on PBUC findings, they were divided into positive and negative PBUC groups. We administered pre-operative antimicrobial treatment to the positive PBUC group and only peri-operative antimicrobial prophylaxis to the negative PBUC group. We examined intra-operative cultures (ICs), including bladder urine culture, renal pelvic urine culture and stone culture, in all cases. We studied the association between the results of PBUC, ICs and infectious complications in both groups. A total of 67 and 95 patients had positive and negative PBUC, respectively. In the positive PBUC group, 19 (28.4%) patients still had positive bladder urine culture after the antibiotic treatment. Positive ICs (43.3% vs. 3.2%, p < 0.001) and post-operative fever (16.4% vs. 2.0%, p = 0.001) were more common in the positive PBUC group than in the negative PBUC group. In the positive PBUC group, 11 patients had a post-operative fever, regardless of the ICs results (6 positive ICs and 5 negative ICs). Furthermore, antimicrobial-resistant bacteria were detected from ICs in 5 patients with positive PBUC, including 4 suffering from a post-operative fever. Although the effect of pre-operative antimicrobial treatment is not definitive, to avoid serious infectious complications, we should recognize high-risk patients and perform more careful infection control based on the pre- and intra-operative culture results.

Chronic Unilateral Hematuria: Compound Papillae Are Likely to Bleed.

Objectives: The present study investigated the recent outcomes of chronic unilateral hematuria (CUH), focusing on the detailed distribution of bleeding points based on the anatomical classification of the pelvicaliceal system. Materials and Methods: We evaluated 75 CUH patients treated in the past decade. Bleeding points were recorded separately as five levels of minor calices (Top, Upper, Middle, Lower, and Bottom). Bleeding point detection, immediate success, and recurrence-free rates were assessed. Results: The median age was 47 (range: 13-81) years. Bleeding points were detected in 62 patients (83%), including at the Top calix in 24 patients (32%), the mid-calices (Upper, Middle, and Lower) in 20 patients (27%), and the Bottom calix in 18 patients (24%). As there are typically six total calices in the mid calices, the probability of bleeding per renal papilla was higher in the compound papillae at the Top and Bottom calices than in the simple papilla at the mid calices. The bleeding point detection rate was significantly higher in the 65 patients with confirmed unilateral gross hematuria than in the 10 patients without confirmation (88% vs 50%, p < 0.01). The immediate success rate was 97% (73/75), and only two patients (3%) needed a second ureteroscopy. Ultimately, all patients achieved the disappearance of gross hematuria, including 13 patients (17%) whose bleeding points were not identified by ureteroscopy. The recurrence-free rate was 100% at a median follow-up of 42 (3-139) months. Conclusions: Compound papillae are more likely to bleed than simple papillae. Therefore, we recommend evaluating the Top and Bottom calices carefully during the initial ureteroscopic observations. Since the patients with confirmed gross hematuria from the unilateral orifice had a higher rate of bleeding point detection than those without confirmation, it is important to perform cystoscopy while the bleeding is persistent.

Successful outcomes of endoscopic lithotripsy in completely bedridden patients with symptomatic urinary calculi.

Due to the aging population, the number of completely bedridden individuals is expected to increase, and such individuals are at high risk of developing urinary calculi. This retrospective study included 32 consecutive bedridden patients, who had undergone endoscopic lithotripsy between 2010 and 2019, and aimed to identify the treatment outcomes of endoscopic lithotripsy for bedridden patients. A total of 45 endoscopic lithotripsies were performed to treat stones (median cumulative diameter, 24 mm). The stone-free rate (SFR) < 4 mm and complete SFR (0 mm) were achieved in 81% and 63% of patients, respectively. Postoperatively, 10 patients (22%) developed symptoms of systemic inflammatory response syndrome, and three patients (7%) had bloodstream infections. Except for one patient (3%) having a retained ureteral stent ultimately died from septic shock, drainage tube-free discharge was achieved in all patients. The 2-year cumulative incidence of stone-related events, and overall mortality rate, were 18% and 27%, respectively. Endoscopic lithotripsy is well tolerated and is associated with a high success rate, even with severe comorbidities and a relatively large stone burden. Physicians should consider performing endoscopic lithotripsy in bedridden patients with symptomatic urinary calculi regardless of their relatively short life expectancy and the remote risk of perioperative mortality.

The significance of intraoperative renal pelvic urine and stone cultures for patients at a high risk of post-ureteroscopy systemic inflammatory response syndrome.

We examined the renal pelvic urine culture (RPUC) and stone culture (SC) during ureteroscopy and evaluated their associations with postoperative systemic inflammatory response syndrome (SIRS). We prospectively collected data of 224 patients who underwent ureteroscopic laser lithotripsy from March 2015 to December 2017. We examined the bladder urine culture pre-operatively. If the patients had positive culture results, we treated them with antibiotics for 5-7 days before surgery based on the sensitivity profile. We collected RPUC and SC samples during surgery. After ureteroscopy, patients were closely monitored for any signs of SIRS. Using a logistic regression model, we analyzed how the clinical factors affected the incidence of SIRS. Pre-operative bladder urine culture (PBUC) was positive in 111 patients (49.6%). Intraoperative RPUC was positive in 43 patients (19.2%), and SC was positive in 34 patients (15.2%). Postoperatively, 23 patients (10.3%) were diagnosed with SIRS. A multivariate analysis revealed that female gender, struvite calculi and positive intraoperative RPUC results were significantly associated with postoperative SIRS. Among the 31 patients who were positive for both PBUC and intraoperative RPUC, the pathogens were not consistent in 11 patients (35.5%). Among the 25 patients who were positive for both PBUC and intraoperative SC, the pathogens were not consistent in 13 patients (52.0%). We recommend collecting RPUC and SC samples during ureteroscopy, especially for patients with high risk factors, including female gender, expected struvite calculi and positive PBUC results.

Chronological changes in epidemiological characteristics of lower urinary tract urolithiasis in Japan.

OBJECTIVES: To determine changes and trends in the annual incidence and epidemiological aspects of lower urinary tract stones in Japan. METHODS: Data about patients who had been diagnosed by urologists in 2015 with first and recurrent lower urinary tract stones were collected from 301 hospitals approved by the Japanese Board of Urology. The estimated annual incidence according to sex, age and stone composition was compared with previous nationwide surveys between 1965 and 2005. RESULTS: The incidence of lower urinary tract stones in Japan has steadily increased from 4.7 per 100 000 in 1965 to 12.0 per 100 000 in 2015. However, the age standardized annual incidence of lower urinary tract stones has remained relatively stable over the same period at 5.5 per 100 000 and 6.0 per 100 000 in 1965 and 2015, respectively. The increase in incidence was most evident among individuals aged ≥80 years. The incidence of calcium oxalate stones has steadily increased among males and females, whereas that of infection-related stones has significantly decreased from 26.2% to 14.3% among men over the past 50 years. CONCLUSIONS: Nationwide surveys suggest a steady increase in the incidence of lower urinary tract stones over a 50-year period in Japan. This trend might reflect changes in the aging population and improved Japanese medical standards.

Proposal for a Simple Anatomical Classification of the Pelvicaliceal System for Endoscopic Surgery.

We herein propose a nomenclature for renal calices and anatomical classification of the renal pelvis for endoscopic surgery. We prospectively collected data on a total of 270 patients (540 kidneys) who underwent CT-urography. We then constructed three-dimensional images of the renal pelvis and examined their morphologic classification. Forty-eight kidneys were excluded from this study because of severe hydronephrosis or large renal cysts. The remaining 492 kidneys were included. We systematically categorized each minor calix into five levels: top, upper, middle, lower, and bottom. The upper, middle, and lower calices were typically found in pairs: anterior and posterior. The most common total number of minor calices was eight (51%), followed by seven (30%). We also classified the form of the pelvis into type I: single pelvis (58%) and type II: divided pelvis (42%), according to the branch patterns of the renal pelvis. In type II, the renal pelvis is always bifurcated into the upper branch (top and upper) and lower branch (middle, lower, and bottom). Type I was subclassified into three types: type Ia (43%), the standard type; type Ib (4%), with a wide pelvis; and type Ic (11%), with a narrow pelvis. This anatomical classification can divide the renal pelvis into two major types (subdivided into four types) and name each minor calix. This simple classification enables to share common intrarenal information, thus leading to the development of concrete treatment strategies.

Chronological changes in the epidemiological characteristics of upper urinary tract urolithiasis in Japan.

OBJECTIVES: To assess epidemiological and chronological trends of upper urinary tract stones in Japan in 2015. METHODS: Patients with a first episode of upper urinary tract stones in 2015 were enrolled in this nationwide survey. The study included all hospitals approved by the Japanese Board of Urology, therefore covering most of the hospitals where urologists practice in Japan. The annual incidence and composition of urolithiasis were evaluated by age and sex. These results were compared with the previous results of the nationwide surveys from 1965 to 2005 to analyze temporal trends. RESULTS: The estimated annual incidence of a first-episode upper urinary tract stone in 2015 was 137.9 (191.9 in men and 86.9 in women) per 100 000. The estimated age-standardized first-episode upper urinary tract stone incidence in 2015 was 107.8 (150.6 in men and 63.3 in women) per 100 000, which did not represent a significant increase since 2005. An equivalent incidence was observed in patients aged >50 years, whereas a reduced incidence was observed in patients aged <50 years in both sexes. The proportion of patients who received percutaneous nephrolithotomy and/or ureteroscopy increased by approximately fivefold in the past 10 years. CONCLUSIONS: The steady increase in the annual incidence of upper urinary tract stones since 1955 leveled off in 2015. The current results show novel trends in the incidence and treatment modalities in the nationwide surveys of urolithiasis in Japan.

Predictive risk factors for systemic inflammatory response syndrome following ureteroscopic laser lithotripsy.

The objective of this study was to investigate risk factors for the development of systemic inflammatory response syndrome following ureteroscopic laser lithotripsy. We retrospectively collected data of 469 patients who underwent ureteroscopic laser lithotripsy at our single institution from February 2008 to June 2016. Details for the patient, the stone, and the surgical factors that potentially contributed to postoperative infection were extracted. Using a logistic regression model, we analyzed how the clinical factors affected the incidence of systemic inflammatory response syndrome. Twenty-seven patients (5.7%) were postoperatively diagnosed with systemic inflammatory response syndrome; of these, 25 patients were diagnosed within 24 h after ureteroscopy. One patient required intensive care unit admission, but no death was reported. A preoperative stent was significantly associated with postoperative systemic inflammatory response syndrome only on univariate analysis, and the reasons for stenting were varied. Multivariate analysis revealed that obstructive pyelonephritis, a positive preoperative bladder urine culture result, and female gender were significantly associated with postoperative systemic inflammatory response syndrome. Patients who experienced obstructive pyelonephritis preceding ureteroscopic laser lithotripsy or had a positive preoperative bladder urine culture result were at an increased risk of systemic inflammatory response syndrome despite receiving appropriate preoperative antibiotic therapy. Regarding the impact of a preoperative stent on postoperative infection, further investigation focusing on reasons for stenting is needed.