Takaaki Inoue

Purpose To evaluate the feasibility of real-time intrarenal pressure (IRP) monitoring using the LithoVue™ Elite (LVE) ureteroscope and assess postoperative infectious complications after retrograde intrarenal surgery (RIRS) in patients with positive urine cultures. Methods This multicenter, single-arm, prospective cohort study (August 2023–October 2024) included patients with upper urinary tract calculi and positive preoperative urine cultures who underwent RIRS with real-time IRP monitoring via the LVE. Irrigation was adjusted to maintain IRPs below 30 mmHg. The primary endpoint was postoperative fever ≥ 38 °C. Secondary endpoints included systemic inflammatory response syndrome (SIRS), stone-free rates, ipsilateral flank pain scores, and complications. Results Of 148 eligible patients, 104 were enrolled. The median operative time and artificial intelligence-corrected IRP were 50 min (interquartile range: 36.8–80.0) and 13.3 mmHg (10.4–19.1), respectively. Postoperative fever occurred in 7.7% of patients, SIRS in 3.8%, and no septic shock was observed. Patients who developed postoperative fever were older (p = 0.019) and had longer preoperative ureteral stent indwelling times (p = 0.015). Univariable linear regression analysis demonstrated that higher body mass index (BMI), irrigation method, and ureteral access sheath tip location were significantly associated with higher intraoperative IRP (all p ≤ 0.005). Higher postoperative white blood cell counts and ipsilateral flank pain scores were also associated with elevated IRP (p = 0.010 and p = 0.032, respectively). In multivariable linear regression analysis, higher BMI and manual irrigation remained independent increased intraoperative IRP predictors (p = 0.042 and p = 0.009, respectively). Conclusion Real-time IRP monitoring using the LVE ureteroscope maintained low intrarenal pressures during RIRS and was associated with a low rate of postoperative fever in high-risk patients. These findings suggest that incorporating IRP monitoring into RIRS protocols is feasible and may improve pressure management in patients with positive urine cultures.

Objectives: To clarify the national transition from conventional percutaneous nephrolithotomy (PCNL) to endoscopic combined intrarenal surgery (ECIRS) and evaluate their safety profiles based on real‐world data. Methods: A retrospective nationwide survey was conducted at 233 institutions in Japan that provided data on percutaneous kidney stone surgeries performed between April 2019 and March 2022. Annual procedure volumes, surgical positions, tract size, irrigation methods, and perioperative complications were analyzed. Results: Among 5555 cases, 1618 were PCNL and 3937 were ECIRS. PCNL decreased significantly over the study period, whereas ECIRS increased and accounted for approximately 75% of the cases by 2021. The GMSV position was used in 81% of ECIRS cases, whereas 76% of PCNL cases were performed in the prone position ( p < 0.001). Mini‐tracts (< 23 Fr) were used in 75.3% of ECIRS and 49.5% of PCNL ( p < 0.001). Severe bleeding (4.7% vs. 1.5%, p < 0.001) and blood transfusion (2.0% vs. 0.7%, p = 0.001) occurred more frequently in PCNL than in ECIRS. Postoperative fever (17.1 vs. 19.2%) or sepsis (2.1 vs. 1.5%) were not significantly different. Conclusions: Although this study was not designed to establish superiority between the procedures, it is the first one to compare the use of PCNL and ECIRS in Japan, and it suggests a marked paradigm shift toward ECIRS. The increasing use of mini‐tracts and the hybrid retrograde‐antegrade approach may be associated with a lower observed rate of bleeding complications. However, postoperative infections remain common with both techniques, highlighting the importance of intrarenal pressure control, optimal patient selection, and meticulous perioperative management.

Purpose: To investigate the safety and efficacy of mini‐endoscopic combined intrarenal surgery (ECIRS) in older patients with renal and ureteral stones. Methods: Consecutive patients with renal or ureteral stones who underwent mini‐ECIRS were retrospectively analyzed at three Japanese tertiary care institutions between 2015 and 2021. Data on patient backgrounds, stone characteristics, and postoperative indications were collected and evaluated. After matching preoperative and intraoperative factors in older patients and other groups, postoperative factors were assessed using univariate analysis. Results: The final analysis included data from 1303 single‐session mini‐ECIRS of 1432 cases collected. The patients were divided into two groups: those aged > 75 and those aged < 75 years, with 121 and 1182 patients. From each group, 112 cases matched for eight factors, performance status, body mass index, sex, hydronephrosis, percutaneous nephrostomy, pyuria, preoperative urinary tract infection, and preoperative ureteral stenting, were selected. The univariate analysis was performed on postoperative factors between the groups of matched older and matched non‐older patients, and there was no significant difference in any factor, including postoperative hospitalization duration, complications, and stone‐free rate (SFR). Conclusions: To the best of our knowledge, this multicenter cohort study is the first to compare the efficacy and safety of the mini‐ECIRS between older patients and other groups. It was discovered that surgery could be performed with a similar quality even in patients aged 75 and older compared to that in other groups.

Purpose The primary aim was to study the in-vitro suction performance of three different Flexible and Navigable Suction Ureteral Access Sheaths (FANS) of two sizes each. The secondary aim was to study the impact of digital occlusion versus thumb sliders on suction performance. Methods We used the 7.5Fr single-use Flexible Ureterorenoscope from Innovex Medical (US27F-12-EU). The six FANS used were: 10/12Fr and 11/13Fr Innovex 40 cm FANS, ClearPetra 46 cm FANS, and Reborn 40 cm FANS. Time taken to suction 100 ml saline was measured. To test efficiency of stone suction, 1000mm³ of 1 to 2 mm stones were distributed equally between the upper and lower poles of a kidney model. Results All three 11/13Fr FANS had suction rates three times faster than their 10/12Fr counterparts (p = 0.001 for all FANS), when digital occlusion was used. Innovex and Clearpetra FANS had faster suction rates than Reborn FANS when suctioning 100 ml saline, for both 10/12Fr and 11/13Fr. For the Innovex FANS, there was no difference in suction rate when using the thumb slider or digital occlusion. However, Reborn FANS had slower suction rates when using the thumb slider compared to digital occlusion for both 10/12Fr and 11/13Fr sizes. Innovex FANS was the fastest in suctioning upper pole calculi, followed by Clearpetra FANS, and Reborn FANS the slowest for 10/12Fr (198s versus 237s versus 537s respectively, p < 0.001) and 11/13Fr (158s versus 174s versus 332s respectively, p < 0.001). 10/12Fr and 11/13Fr Reborn FANS were not able to reach the lower pole calculi. Between Clearpetra and Innovex, there was no significant difference in time taken to suction lower pole calculi. Conclusions Faster suction was achieved with 11/13Fr instead of 10/12Fr FANS. With digital occlusion, the Innovex and Clearpetra FANS both performed similarly better in their suction performance than the Reborn FANS.

Objective: To assess the safety of mini-endoscopic combined intrarenal surgery (mini ECIRS) in patients with a poor performance status (PS). Methods: A retrospective analysis was conducted on 1132 patients who underwent mini-ECIRS at 3 hospitals between January 2015 and December 2021. Patients were classified according to their PS (PS0-1 and PS2-4 groups) and compared between the groups in terms of preoperative drainage status, such as ureteral stent or percutaneous nephrostomy (PNS), stone characteristics, surgical outcomes, and postoperative fever. Multivariate logistic regression models were used to identify the predictive factors for postoperative fever in each PS group. Results: Patients in the PS2-4 group were older and had a higher stone burden than those in the PS0-1 group. The stone-free rates and surgical success rate were similar between the PS groups, but PS2-4 patients had higher rates of postoperative fever without preoperative drainage. Stone composition analysis revealed a higher preva lence of infectious stones in the PS2-4 group. In the PS0-1 group, PNS reduced postop erative fever risk (odds ratio (OR): 0.65, 95% CI: 0.48-0.89, P = .01), and history of febrile urinary tract infection, stone burden ! 30 mm, number of involved calyces ! 4, and female sex were independent risk factors. Notably, in the PS2-4 group, PNS remained effective against postoperative fever (OR: 0.24, 95% CI: 0.07-0.80, P = .02), while no other factors were significant. Conclusion: The mini-ECIRS was effective even in PS-poor patients, and they may ben efit more from preoperative PNS placement than normal PS cases. Cite this article as: Tabei T, Ito H, Inoue T, et"al. Mini-endoscopic combined intrarenal surgery in patients with poor performance status: A retrospective analysis of postoperative fever in over 1,000 cases. Urol Res Pract. 2025;51(3):89-94.

Background/Objectives: Intrarenal pressure (IRP) plays a critical role in ensuring the safety of retrograde intrarenal surgery (RIRS), as elevated IRP is associated with complications such as pyelovenous backflow, infection, and renal injury. LithoVue™ Elite (LVE) is the first commercially available ureteroscope (URS) capable of providing real-time IRP measurements. Conventionally, IRP has been measured via a percutaneous nephrostomy catheter (PNC), which may not accurately reflect dynamic changes during endoscopic procedures. Recently, small ureteral access sheaths (UASs) have been increasingly used to minimize ureteral injury risk. This study aimed (1) to assess the accuracy of LVE compared with that of IRP measured by a PNC and (2) to evaluate appropriate irrigation settings suitable for small UASs using porcine kidney models and LVE. Methods: An 11/13-Fr UAS and a 10/12-Fr UAS were inserted into each model, and an automatic irrigation pump (AIP) and hand pumping (HP) with a 20-cc syringe were used. IRP was measured at various LVE tip positions (renal pelvis and upper, middle, and lower calyces) with different irrigation settings, repeated four times in each. Simultaneously, the IRP via the PNC located in the upper calyx and renal pelvis was measured. Results: LVE showed high concordance with the PNC across the upper, middle, and lower calyces (p > 0.05). However, at the renal pelvis, LVE measured IRP values that were significantly higher than the PNC by a mean of 1.93 ± 0.93 mmHg (p < 0.001). For the 11/13-Fr UAS, the IRP remained below 30 mmHg across all irrigation settings with an AIP and HP. In contrast, the 10/12-Fr UAS maintained 30 mmHg only with limited AIP settings, while HP resulted in high IRP, exceeding 100 mmHg at any location. Intergroup comparisons demonstrated that the IRP with the 10/12-Fr UAS was significantly higher than that with the 11/13-Fr UAS at any irrigation pressure setting across all URS tip positions (p < 0.05). Intragroup comparisons indicated a significant pressure difference between the upper, middle, and lower calyces and the renal pelvis in both models at all irrigation settings (p < 0.05). Conclusions: LVE provided accurate IRP measurements compared to the PNC. The IRP was significantly influenced by UAS size, irrigation setting, and URS tip position. When using small UASs, selecting appropriate irrigation settings is essential to maintain the safe threshold.

Objective: This study was performed to evaluate the efficacy of using a percutaneous 4.5‐Fr semi‐rigid ureteroscope (4.5‐rURS) and preoperative clinical factors in the performance of the through‐and‐through guidewire technique (T&TGW) under the guidance of retrograde flexible ureteroscope (fURS)‐assisted fluoroscopy during minimally invasive endoscopic combined intrarenal surgery (mini‐ECIRS). Methods: In total, 123 patients who underwent mini‐ECIRS with percutaneous 4.5‐rURS assistance for large kidney stones in the flank‐free modified Valdivia position were retrospectively evaluated. The primary outcome was the achievement rate of T&TGW, defined as percutaneous insertion of a guidewire that passed down the ureter and exited outside the external urethral meatus. The secondary outcome was the rate of percutaneous 4.5‐rURS assistance required to successfully perform T&TGW. Results: The stone‐free rate was 81.2%, including no residual fragments in 72.3% of patients. T&TGW was successful in 119 (96.6%) patients, which was necessary using retrograde fURS‐assisted fluoroscopic guidance in 61 (49.5%) patients, whereas 4.5‐rURS assistance was required in 58 (47.1%) patients. Guidewire migration under the renal pelvis mucosa was found in 10 (8.1%) patients. Preoperative factors associated with failed T&TGW using retrograde fURS‐assisted fluoroscopic guidance were the puncture site in the lower calyx (odds ratio, 0.125; confidence interval, 0.043–0.364; p = 0.001) and the presence of preoperative hydronephrosis in the renal calyx of the puncture site (odds ratio, 0.261; confidence interval, 0.093–0.730; p = 0.011). Conclusion: Percutaneous 4.5‐rURS assistance facilitated successful T&TGW in cases of failed access under retrograde fURS‐assisted fluoroscopic guidance in supine mini‐ECIRS and a useful option to find a migrated guidewire in the wrong direction.

Purpose: To identify risk factors of infectious complications following mini‐endoscopic combined intrarenal surgery (ECIRS) in patients with renal or ureteral stones.Methods: We retrospectively analyzed consecutive patients with renal or ureteral stones who underwent mini‐ECIRSs at three Japanese tertiary institutions between 2015 and 2021. Data were collected and evaluated regarding patient backgrounds, stone characteristics, and postoperative complications. Among the various complications, multivariable logistic regression analysis was performed using preoperative and intraoperative factors for postoperative fever (≥ 38°C) and septic shock to identify independent risk factors.Results: The data of 1432 cases were collected. Finally, 1035 cases of single‐session mini‐ECIRS were included in the analysis. In infectious complications, postoperative fever and septic shock were observed in 273 and 21 patients (26.4% and 2.0%). A multivariable logistic regression model identified female (p < 0.001), ureteral stones (p < 0.001), preoperative pyuria (p < 0.001), preoperative urinary tract infection (p = 0.045), preoperative percutaneous nephrostomy (p = 0.001), and operation time (p = 0.017) as predictors of postoperative fever. For septic shock, female (p < 0.001) was shown as a risk factor.Conclusions: To the best of our knowledge, this multicenter cohort study is the largest study investigating infectious complications following mini‐ECIRS. Female was a common risk factor for both postoperative fever and septic shock, suggesting that surgeons should pay extra attention to vital signs during the procedure and postoperative infectious complications in mini‐ECIRSs for these patients.

This third edition of the Japanese Clinical Practice Guidelines for Urinary stones (2023) has been developed under the leadership of the Japanese Urological Association, the Japanese Society of Endourology and Robotics, and the Japanese Society on Urolithiasis Research. This revision adheres to the Minds Manual for Guideline Development (2017) and incorporates new findings from a nationwide survey conducted in 2015, which highlighted the epidemiological characteristics of urolithiasis in Japan since the previous guidelines were published in 2013. A significant advancement in this edition is the systematic review (SR) methodology applied to formulate recommendations for 12 clinical questions (CQs). Both quantitative and qualitative SRs were performed, leading to recommendations determined through consensus among 21 members of the guideline development group. Additionally, nine algorithms were created to support clinical decision‐making based on these findings. Topics not addressed by the CQs, considered as foundational knowledge, are outlined in an “Explanation of Related Matters” section, which includes 26 items. This article provides an overview of these guidelines. This section ensures that practitioners have access to comprehensive information, covering aspects of urolithiasis management beyond the scope of the systematic reviews. This article provides an overview of the guidelines, emphasizing their relevance and importance in improving the management and treatment outcomes for patients with urinary stones. The guidelines are designed to be a practical resource for clinicians, facilitating evidence‐based care in the evolving landscape of urolithiasis treatment.