Influence of tract location on the outcomes of endoscopic combined intrarenal surgery: A retrospective analysis of 1000 cases.

OBJECTIVES: This study aimed to investigate the influence of tract location on surgical outcomes in endoscopic combined intrarenal surgery (ECIRS), considering the location of residual stones. METHODS: From January 2015 to December 2021, 1417 consecutive patients underwent ECIRS in three hospitals. After excluding patients with preoperative percutaneous nephrostomy, intended multi-stage procedures, those with a tract in the renal pelvis, and those with multiple tracts, 1000 patients were retrospectively analysed by comparing three groups based on tract location: group 1 (upper calyx), group 2 (middle calyx), and group 3 (lower calyx). A multivariate logistic regression model was implemented to assess whether the tract location independently affected the stone-free status. RESULTS: Patient characteristics were significantly different among the groups in terms of age, stone laterality, presence of calyceal stones, and hydronephrosis. There were no differences in stone-free rate (SFR) among the three groups. Multivariate analysis indicated that the tract location (group 1 or 2 compared with group 3) did not significantly affect the stone-free status (odds ratio = 1.4, 0.9-1.9, p = 0.066). Surgical duration significantly varied among the groups, with the shortest time observed in group 1. Organ injury was observed exclusively in group 1 (1.13%). Residual fragments were predominantly found in the lower calyx, with the calyx associated with the tract being the second most common location. CONCLUSIONS: Tract location does not significantly affect SFR. To improve the SFR, observation of the lower calyx and tract placement is important.

Enfortumab vedotin prolongs overall survival in metastatic urothelial carcinoma following pembrolizumab therapy in real-world data.

OBJECTIVE: In December 2021, enfortumab vedotin (EV), an antibody-drug conjugate directed against nectin-4, was approved in Japan as a new treatment after platinum-containing chemotherapy and PD-1/PD-L1 inhibitors. This study evaluated, using real-world data, the efficacy and safety of EV therapy in patients with metastatic urothelial carcinoma (mUC). MATERIALS AND METHODS: Fifty-five patients with mUC who discontinued pembrolizumab therapy due to disease progression between June 2018 and April 2023 at Yokohama City University Hospital were evaluated retrospectively. Of the 55 patients, 25 received EV therapy (EV group) and 30 did not (non-EV group). All patients who underwent EV therapy were diagnosed with disease progression after the approval of EV in Japan. RESULTS: The median (range) follow-up period after pembrolizumab discontinuation was 6.3 (0.7-31.1) months. There were eight (32.0%) deaths due to cancer in the EV group and 27 (90.0%) in the non-EV group. The overall survival (OS) after pembrolizumab discontinuation was not reached in the EV group versus 2.6 months in the non-EV group (p < 0.001). A multivariate analysis revealed that EV therapy (EV vs. non-EV group; hazard ratio 0.26; 95% confidence interval 0.16-0.41; p < 0.001) was an independent prognostic factor for OS. CONCLUSION: EV prolonged OS in mUC following pembrolizumab therapy in real-world data.

Real-world sequential treatment patterns and clinical outcomes among patients with advanced urothelial carcinoma in Japan.

OBJECTIVES: Immune checkpoint inhibitors and enfortumab vedotin have opened new avenues for sequential treatment strategies for locally advanced/metastatic urothelial carcinoma (la/mUC). In the pre-enfortumab vedotin era, many patients could not receive third-line treatment owing to rapid disease progression and poor general status. This study aimed to analyze real-world sequential treatment practices for la/mUC in Japan, with a focus on patients who do not receive third-line treatment. METHODS: We analyzed data for 1023 la/mUC patients diagnosed between January 2020 and December 2021 at 54 institutions from a Japanese nationwide cohort. RESULTS: At the median follow-up of 28.5 months, the median overall survival from first-line initiation for 905 patients who received systemic anticancer treatment was 19.1 months. Among them, 81% and 32% received second- and third-line treatment. Notably, 52% had their treatment terminated before the opportunity for third-line treatment. Multivariate logistic regression analysis revealed that low performance status (≥1), elevated neutrophil-to-lymphocyte ratio (≥3), and low body mass index (<21 kg/m2) at the start of first-line treatment were independent risk factors for not proceeding to third-line treatment (p = 0.0024, 0.0069, and 0.0058, respectively). In this cohort, 33% had one of these factors, 36% had two, and 15% had all three. CONCLUSIONS: This study highlights the high frequency of factors associated with poor tolerance to anticancer treatment in la/mUC patients. The findings suggest the need to establish optimal sequential treatment strategies, maximizing efficacy within time and tolerance constraints, while concurrently providing strong supportive care, considering immunological and nutritional aspects.

[Real-World Experience and Complications with Intermittent Balloon Catheters : A Predictor Analysis].

Intermittent balloon catheterization with a reusable and temporary balloon catheter that could be implanted and removed by the patient was developed in Japan in 1995. Although the intermittent balloon catheter has the potential to improve the patient's quality of life (QOL), appropriate information and guidelines are needed to prevent complications such as hematuria and urinary tract infection. This study aimed to assess the real-world practice, complications, and problems associated with the use of intermittent balloon catheters and provide useful information for future medical care. We conducted a questionnaire survey on patients with spinal cord lesions who currently use or have used intermittent balloon catheters in the past. Seventy-six patients with spinal cord lesions who visited Kanagawa Rehabilitation Hospital from August 2020 to March 2021 and gave consent for participating in this study were included. QOL scores before and after intermittent balloon catheter use showed significant improvement after use. Forty-six of the 76 (61.3%) patients had complications. Overall complications were significantly associated with male sex and possibly linked to non-traumatic spinal cord lesions.

[A Case of Testicular Torsion of Retractile Testis Requiring Orchidectomy].

We report a case of testicular torsion in an 8-year-old who was referred to our hospital for right groin pain. He was diagnosed with right retractile testis during a 12-month check-up. However, instead of performing orchiopexy, he was placed under observation until the age of 5, after which he did not seek medical attention. Physical examination revealed swelling and tenderness in the right inguinal region and no palpable testis in the right scrotum. Ultrasound and computed tomography revealed right testicular torsion, and emergency surgery was performed. Intraoperative findings revealed a dark and ischemic testis that was twisted at 180°in the right inguinal region. There was no improvement in blood flow even after the testicular torsion was released; therefore, right orchidectomy with left orchiopexy was performed. Although the incidence of testicular torsion is higher in patients with an undescended testis than in those with a normally positioned scrotal position testis, reports of testicular torsion associated with a retractile testis are rare.

Long-term clinical course of two rare cases of synovitis-acne-pustulosis-hyperostosis-osteomyelitis syndrome involving only unilateral femur.

Synovitis-acne-pustulosis-hyperostosis-osteomyelitis (SAPHO) syndrome is characterised by aseptic osteitis and is often complicated by pustular dermatitis, such as palmoplantar pustulosis or acne. Although bone lesions are most found in the anterior thoracic region or spine, femoral lesions are not well documented in the literature. There is no established treatment for this condition, and few reports have described its long-term course. Here, we describe two cases of SAPHO syndrome involving the femur and discuss their long-term follow-up. A 40-year-old man (Case 1) presented with right thigh pain. Fifteen years after the initial diagnosis, the pain could be controlled with minomycin, salazosulfapyridine, and methotrexate. X-rays of the femur showed gradual cortical thickening. Although there were waves of pain, it gradually improved with the adjustment of drugs 25 years following the initial diagnosis. A 35-year-old man (Case 2) with right thigh pain was prescribed salazosulfapyridine and methotrexate; however, these were ineffective. Alendronate and guselkumab also proved ineffective. Ultimately, infliximab was started 9 years following disease onset, and pain became manageable. X-rays of the femur showed cortical thickening. SAPHO syndrome can be managed with drug therapies, such as nonsteroidal anti-inflammatory drugs, methotrexate, and conventional synthetic disease-modifying antirheumatic drugs; however, there are occasional treatment-resistant cases.

[A case of recurrent Campylobacter fetus meningitis, occurring two months after the |initial infection was successfully treated].

A 43-year-old man was admitted to our department due to fever and headache. The cerebrospinal fluid analysis confirmed bacterial meningitis. Campylobacter species were isolated from blood cultures on the third day of admission. The patient was treated with meropenem (MEPM) and discharged on the 17th day. However, he experienced a recurrence of meningitis and was readmitted on the 68th day, initiating MEPM therapy. Campylobacter fetus was isolated from cerebrospinal fluid cultures on the 74th day. MEPM was continued until the 81st day, followed by one month of minocycline (MINO) therapy. The patient had an uneventful recovery without further recurrence. This case highlights the potential for recurrence of Campylobacter fetus meningitis approximately two months after the resolution of the initial infection. In addition to carbapenem therapy for at least two weeks, the adjunctive administration of MINO may be beneficial.

Impact of chronic kidney disease stages on surgical and functional outcomes in robot-assisted partial nephrectomy for localized renal tumors.

The influence of chronic kidney disease stage on robot-assisted partial nephrectomy outcomes remains underexplored. This study aimed to assess the impact of chronic kidney disease stage on functional and surgical outcomes of robot-assisted partial nephrectomy and identify preoperative predictors of significant postoperative 1-year renal-function loss (RFL). Clinical data of 408 patients who underwent robot-assisted partial nephrectomy at Yokohama City University Hospital between 2016 and 2023 were retrospectively reviewed. The da Vinci Surgical System was applied in all patients, and outcomes assessed included surgical parameters, postoperative estimated glomerular filtration rate, trifecta and pentafecta achievements, and complications. Significant RFL was defined as estimated glomerular filtration rate reduction ≥ 25% from baseline. Higher chronic kidney disease stages correlated with older age, hypertension, diabetes, and solitary kidneys. Postoperative estimated glomerular filtration rate decline was most pronounced in patients with chronic kidney disease stages 4-5. Although the chronic kidney disease stage did not significantly affect most surgical parameters, pentafecta achievement was higher in patients with chronic kidney disease stage 3 than in those with stages 4-5. Two patients required hemodialysis after robot-assisted partial nephrectomy. Multivariable logistic regression analysis showed that preoperative hemoglobin level and maximum tumor diameter were significant predictive factors for significant RFL. In conclusion, preoperative CKD stage did not influence on surgical outcome except for pentafecta achievement. RAPN may be feasible for patients with CKD stages 4-5 because of no rapid progression to hemodialysis induction and no procedure-related mortality. Preoperative hemoglobin levels and tumor diameter emerged as predictors of significant RFL.

Impacts of Complete Endophytic Renal Tumors on Surgical, Functional, and Oncological Outcomes of Robot-Assisted Partial Nephrectomy.

Objective: Complete endophytic renal tumors (CERTs) are the most challenging for robot-assisted partial nephrectomy (RAPN). This study aimed to determine the impact of CERT on outcomes of RAPN. Methods: All RAPN cases for localized renal tumor undertaken at Yokohama City University Hospital between 2016 and 2023 were enrolled. Tumor characteristics and surgical, functional, and oncologic outcomes of RAPN were compared between CERT and non-CERT groups. Results: Consecutive 666 patients were enrolled, and 76 (11.4%) were identified as CERT (3 points of "E" score). CERT showed smaller tumor diameters (p < 0.001), more predominant hilar tumor (p = 0.029), higher "N" scores (p < 0.001) and "L" scores (p = 0.006) than non-CERT. The CERT group showed longer warm ischemia times (p < 0.001), more frequent positive surgical margins (p = 0.028), and relatively lower trifecta achievement rates (p = 0.101) than the non-CERT group. In multivariable analysis, the CERT was an independent predictor for trifecta achievement but not for pentafecta achievement. Conclusions: CERT was associated with longer warm ischemia time, positive surgical margin, and lower trifecta achievement, but not with surgical complication and pentafecta achievement in RAPN. This study suggested that CERT had limited influence on long-term renal functional preservation; however, it had strong impacts on short-term surgical outcome.

NRIP1 regulates cell proliferation in lung adenocarcinoma cells.

Nuclear receptor interacting protein 1 (NRIP1) is a transcription cofactor that regulates the activity of nuclear receptors and transcription factors. Functional expression of NRIP1 has been identified in multiple cancers. However, the expression and function of NRIP1 in lung adenocarcinoma have remained unclear. Thus, we aimed to clarify the NRIP1 expression and its functions in lung adenocarcinoma cells. NRIP1 and Ki-67 were immunostained in the tissue microarray section consisting of 64 lung adenocarcinoma cases, and the association of NRIP1 immunoreactivity with clinical phenotypes was examined. Survival analysis was performed in lung adenocarcinoma data from The Cancer Genome Atlas (TCGA). Human A549 lung adenocarcinoma cell line with an NRIP1-silencing technique was used in vitro study. Forty-three of 64 cases were immunostained with NRIP1. Ki-67-positive cases were more frequent in NRIP1-positive cases as opposed to NRIP1-negative cases. Higher NRIP1 mRNA expression was associated with poor prognosis in the TCGA lung adenocarcinoma data. NRIP1 was mainly located in the nucleus of A549 cells. NRIP1 silencing significantly reduced the number of living cells, suppressed cell proliferation, and induced apoptosis. These results suggest that NRIP1 participates in the progression and development of lung adenocarcinoma. Targeting NRIP1 may be a possible therapeutic strategy against lung adenocarcinoma.

The effect of the conduit size on middle-term outcomes in patients with extracardiac total cavopulmonary connection.

OBJECTIVES: The 18- and 16-mm conduits in extracardiac total cavopulmonary connection (eTCPC) were reported to be optimal based on energy loss and flow stagnation at the relatively early phase. However, because the artificial conduit lacks growth potential, we have recently encountered some cases in which the conduit needs to be changed several years after eTCPC. These cases prompted us to reconsider the surgical strategy for eTCPC. METHODS: We reviewed our 20-year single-centre experience with eTCPC patients (n = 256) to compare the 18-mm conduit (n = 195) and 16-mm conduit (n = 61) in terms of mortality and morbidity. RESULTS: The 16-mm conduit was used significantly more frequently in patients whose main chamber was right ventricle (P < 0.001). There was also a significant difference in preoperative inferior vena cava pressure (P = 0.008). There was a significant difference in the actuarial rate of freedom from late-occurring complications, including mortality, between the 2 groups (P = 0.003). There was a significant difference in the actuarial rate of reoperation-free survival (P = 0.042); however, there was no significant difference in resurgical intervention for the conduit (P = 0.333). In multivariate analysis, preoperative inferior vena cava pressure was an independent predictor for late-occurring complications (hazard ratio 1.19; P = 0.026). Conduit size (18 or 16 mm) itself was not an independent predictive factor for late-occurring complications (P = 0.690). CONCLUSIONS: The mid-term clinical outcomes in patients who underwent eTCPC were excellent with low mortality. Preoperative inferior vena cava pressure was the only predictive risk factor for postoperative morbidity, and the 16 mm conduit was not predictive thereof.

Predictors of postoperative storage symptoms in male patients with lower urinary tract symptoms: A retrospective analysis of prostate surgery for benign prostatic enlargement.

OBJECTIVES: This study investigated the effects of prostate surgery on storage symptoms in male patients with lower urinary tract symptoms (LUTS) from benign prostatic enlargement (BPE). This study aimed to identify patient characteristics associated with improved, unchanged, and deteriorated post-surgical storage symptoms and to identify the risk factors for non-improvement or deterioration. METHODS: A retrospective analysis of 586 prostate surgeries performed between 2016 and 2022 at Yokosuka Kyosai Hospital was conducted on patients with LUTS and at least one storage symptom preoperatively. Patients with active urinary tract infection, prostate/bladder cancer, urethral strictures, or dementia were excluded. The study enrolled 230 patients and assessed storage symptoms using the International Prostate Symptom Score (IPSS). RESULTS: Overall, storage symptoms improved, remained unchanged, and deteriorated in 87.0%, 5.7%, and 7.4% of patients, respectively. The patients in the deteriorated group were significantly older, whereas those in the no-change group had smaller prostate volumes. Patient-reported outcome scores (IPSS, IPSS-QoL, and BII) were significantly higher in the improved group. The predictors of non-improvement included low IPSS storage score, cardiovascular disease, and diabetes mellitus. Predictors of deterioration included advanced age and low IPSS storage score. CONCLUSIONS: Patients with severe LUTS showed greater postoperative improvement in storage symptoms. A low IPSS storage score predicted non-improvement and deterioration. Advanced age, low IPSS storage score, and a history of cardiovascular disease and diabetes mellitus were identified as key predictors. Awareness of these factors may guide preoperative counseling and improve decision-making in prostate surgery, ensuring more personalized and effective treatment strategies.

Surgical proficiency in laparoscopic radical cystectomy with extracorporeal urinary diversion and its adequacy for the execution of robot-assisted radical cystectomy with intracorporeal urinary diversion.

INTRODUCTION: The number of facilities adopting intracorporeal urinary diversion (ICUD) using robots instead of extracorporeal urinary diversion (ECUD) is increasing. However, guidance on how to introduce robot-assisted radical cystectomy (RARC) + ICUD in each urological institute remains unclear. This study aimed to verify the feasibility of the transition from laparoscopic radical cystectomy (LRC) + ECUD to RARC + ICUD. METHODS: We retrospectively analyzed 26 consecutive patients who underwent ICUD with an ileal conduit after RARC between 2018 and 2020 (RARC + ICUD early group). We then compared these patients with 26 consecutive patients who underwent ECUD with an ileal conduit after LRC between 2012 and 2019 (LRC + ECUD late group) at Yokohama City University Hospital. RESULTS: In the RARC + ICUD early group compared with the LRC + ECUD late group, the median total operation time was 516 versus 532.5 min (P = .217); time to cystectomy, 191 versus 206.5 min (P = .234); time of urinary diversion with an ileal conduit, 198 versus 220 min (P = .016); postoperative maximum C-reactive protein levels, 6.98 versus 12.46 mg/L (P = .001); number of days to oral intake, 3 versus 5 days (P = .003); length of hospital stay, 17 versus 32 days (P < .001). The postoperative complication rates (within 90 days) were 23.1% and 42.3% in the RARC + ICUD early and LRC + ECUD late groups, respectively (P = .237). Clavien-Dindo classification ≥3 was noted in 1 and 4 patients in the RARC + ICUD early and LRC + ECUD late groups, respectively (P = .350). CONCLUSION: Regarding perioperative outcomes, the RARC + ICUD early group was not inferior to the LRC + ECUD late group. This study suggests the feasibility of a transition from LRC + ECUD to RARC + ICUD.

Enzalutamide Prolonged the Duration of Drug Use in Comparison to Abiraterone Acetate and Cabazitaxel after Upfront Docetaxel: A Large Japanese Database Study.

INTRODUCTION: In the United States, a total of 268,490 men were found to have prostate cancer in 2022, thus making it the most common cancer in men, accounting for 27% of all cancers in the male population. Among all cancers in men, it was the fifth leading cause of death, with 34,500 deaths and a mortality rate of 11%. In 2019, the total number of cases was 94,748, making it the leading cancer in males, accounting for 11% of all male cancers. In terms of mortality, it ranked seventh, with 13,217 deaths and a mortality rate of 1.6%. However, new treatment options for metastatic castration-sensitive prostate cancer (mCSPC) have emerged. Docetaxel has been shown to be effective for both mCSPC and castration-resistant prostate cancer (CRPC). Upfront docetaxel has not been approved in Japan, nor has it been validated in large-scale studies. Furthermore, several agents can be used after docetaxel treatment, but it is unclear which is the most effective. We used a large Japanese health insurance database to determine which agent would be the most effective as a next-line therapy in patients who had received docetaxel. MATERIALS AND METHODS: We used data from medical institutions using the Diagnosis Procedure Combination (DPC), which provides a comprehensive evaluation of medical classifications. The Medical Data Vision database covers approximately 23% of DPC hospitals in Japan. This study analyzed 2938 patients with mCSPC who received docetaxel, followed by CRPC, between April 2008 and December 2021. The study focused on three agents: enzalutamide, abiraterone acetate, and cabazitaxel. Other agents were excluded due to the small number of patients. The following data were analyzed: age, date of CRPC diagnosis, presence of bone metastasis, drug type, and prognosis. RESULTS: This study included 1997 patients with CRPC after upfront docetaxel therapy for mCSPC (enzalutamide [ENZ] group, n = 998; abiraterone acetate [ABI] group, n = 617; and cabazitaxel [CBZ] group, n = 382). The overall survival (OS) time from drug initiation was 456 days in the enzalutamide group, which was significantly longer than that in the cabazitaxel group (p = 0.017, HR 0.94) (ENZ: ABI p = 0.54, HR 0.94; ABI: CBZ p = 0.14, HR 0.75). OS was also compared for the third-line drug in the group that received enzalutamide as the second-line drug, the group that used abiraterone acetate as the third-line drug (ENZ-ABI group), and the group that used abiraterone acetate as the second-line drug. OS from the start of the third-line drug was compared between the ENZ-ABI group and the ABI-ENZ group, which received enzalutamide as the third-line drug, but showed no significant difference (269 vs. 281 days, p = 0.85; HR 1.03). CONCLUSION: ENZ was shown to prolong OS relative to cabazitaxel after the cessation of docetaxel. ENZ was associated with a longer duration of drug use than ABI and CBZ.

[COMPARING LAPAROSCOPIC AND ROBOT-ASSISTED PYELOPLASTY FOR URETERO-PELVIC JUNCTION OBSTRUCTION: INITIAL EXPERIENCE FROM A SINGLE CENTER].

(Objective) To compare the initial results of robot-assisted laparoscopic pyeloplasty (RALP) and laparoscopic pyeloplasty (LP) for uretero-pelvic junction obstruction (UPJO). (Methods) Between April 2008 to October 2021, we identified 104 cases of UPJO where LP was performed and 18 cases where RALP was performed at our hospital. We retrospectively analyzed their perioperative outcomes. Furthermore, we recorded the operative times for each cases of LP and RALP. (Results) The median operative time for RALP was 141 minutes, which was significantly shorter than that for LP (204 minutes). No patient in the RALP group demonstrated any Clavien-Dindo complications (≥grade 3). During the observation period, improvement of symptoms was observed in all cases. The median suturing time in RALP was 38 minutes. Compared with the last 20 cases of LP, the time to expose the uretero-pelvic junction, the time of renal pelvis incision, and suturing time were significantly shorter in RALP. In addition, the console and suturing times were stable since the initial stage. In cases with a high grade of hydronephrosis, there was a large variation in the time to expose the uretero-pelvic junction and suture the renal pelvis and ureter in LP; however, this variation was smaller in RALP. (Conclusion) At our hospital, RALP for UPJO is considered to be a safe procedure. In the future, it is necessary to consider the long-term results and effectiveness of RALP.

Correlation between Higher Aging Males' Symptoms Scores and a Higher Risk of Lower Urinary Tract Symptoms.

BACKGROUND: Late-onset hypogonadism (LOH) is a condition caused by the decline of testosterone levels with aging and is associated with various symptoms, including lower urinary tract symptoms (LUTSs). Although some reports have shown that testosterone replacement treatment for LOH improves LUTSs, no large study has revealed a correlation between LUTSs and LOH. This study investigated the correlation between the severity of LOH and LUTSs in Japanese males >40 years of age using a web-based questionnaire with the Aging Males' Symptoms (AMS) scale. METHODS: We asked 2000 Japanese males to answer both the AMS and IPSS/QOL questionnaires using a web-based survey. Among these 2000 individuals, 500 individuals were assigned to each age group. RESULTS: The IPSS total score was positively correlated with the severity of AMS (shown as median [mean ± SD]): no/little group, 2 (3.67 ± 5.36); mild group, 6 (7.98 ± 6.91); moderate group, 11 (12.49 ± 8.63); and severe group, 16 (14.83 ± 9.24) (p < 0.0001). CONCLUSIONS: Individuals with higher AMS values, representing cases with severe LOH symptoms, had a higher risk of experiencing nocturia and LUTSs than those with lower AMS values.

Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones.

To establish a safer and more efficient treatment strategy with mini-endoscopic combined intrarenal surgery (ECIRS), the present study aimed to develop models to predict the outcomes of mini-ECIRS in patients with renal and/or ureteral stones. We retrospectively analysed consecutive patients with renal and/or ureteral stones who underwent mini-ECIRS at three Japanese tertiary institutions. Final treatment outcome was evaluated by CT imaging at 1 month postoperatively and stone free (SF) was defined as completely no residual stone or residual stone fragments ≤ 2 mm. Three prognostic models (multiple logistic regression, classification tree analysis, and machine learning-based random forest) were developed to predict surgical outcomes using preoperative clinical factors. Clinical data from 1432 ECIRS were pooled from a database registered at three institutions, and 996 single sessions of mini-ECIRS were analysed in this study. The overall SF rate was 62.3%. The multiple logistic regression model consisted of stone burden (P < 0.001), number of involved calyces (P < 0.001), nephrostomy prior to mini-ECIRS (P = 0.091), and ECOG-PS (P = 0.110), wherein the area under the curve (AUC) was 70.7%. The classification tree analysis consisted of the number of involved calyces with an AUC of 61.7%. The random forest model showed that the top predictive variable was the number of calyces involved, with an AUC of 91.9%. Internal validation revealed that the AUCs for the multiple logistic regression model, classification tree analysis and random forest models were 70.4, 69.6 and 85.9%, respectively. The number of involved calyces, and a smaller stone burden implied a SF outcome. The machine learning-based model showed remarkably high accuracy and may be a promising tool for physicians and patients to obtain proper consent, avoid inefficient surgery, and decide preoperatively on the most efficient treatment strategies, including staged mini-ECIRS.