Three-dimensional topology-based T-index as an indicator of surgical difficulty of partial nephrectomy in patients with small renal mass.

PURPOSE: To accurately describe the three-dimensional topology of renal tumors, our study suggests a new nephrometry scoring system, the T-index, that combines information about intraparenchymal extension and peripherality of the renal tumor. MATERIALS AND METHODS: This study included 113 patients who underwent partial nephrectomy for small clear cell renal cell carcinoma between 2007 and 2014. Manual segmentation of the renal parenchyma, sinus, and tumor was performed using preoperative computed tomography images. The T-index was calculated by adding the reciprocals of the distances from all points on the tumor-parenchyma interface to the renal sinus. Correlations with perioperative factors and the impact of the T-index on postoperative complications were evaluated and compared with existing nephrometry scoring systems (PADUA, RENAL, contact surface area [CSA], and C-index). RESULTS: The mean value of the T-index among the 113 patients was 116.1±100.5 (1/mm). The T-index showed the strongest correlation with perioperative factors compared with other nephrometry scoring systems. The T-index was able to predict the risk for postoperative complications, either overall (p=0.015) or major complications (p=0.030). A predictive model based on the T-index of the overall postoperative complications presented the best performance (area under the curve, 0.692; 95% CI, 0.599-0.776) compared with other nephrometry scoring systems. CONCLUSIONS: The T-index can be considered as a single value comprising key structural indicators for surgical complexity. Our findings suggest that the T-index can provide a quantitative and objective scoring system associated with surgical difficulty and postoperative complications of partial nephrectomy.

Tumor enucleation for the treatment of T1 renal tumors: A systematic review and meta-analysis.

PURPOSE: To evaluate the clinical efficacy and safety of tumor enucleation (TE) compared with partial nephrectomy (PN) for T1 renal cell carcinoma. MATERIALS AND METHODS: According to protocol, we searched multiple data sources for published and unpublished randomized controlled trials and nonrandomized studies (NRSs) in any language. We performed systematic review and meta-analysis according to the Cochrane Handbook for Systematic Reviews of Interventions and rated the certainty of the evidence (CoE) using the GRADE framework. RESULTS: We are uncertain about the effects of TE on perioperative (mean difference [MD] 3.38, 95% CI 1.52 to 5.23; I²=68%; 4 NRSs; 942 participants; very low CoE) and long-term (MD 2.31, 95% CI -1.40 to 6.01; I²=57%; 4 NRSs; 542 participants; very low CoE) residual renal function. TE may result in little to no difference in short-term residual renal function (MD 1.04, 95% CI 0.25 to 1.83; I²=0%; 2 NRSs; 256 participants; low CoE). We are uncertain about the effects of TE on cancer-specific mortality (risk ratio [RR] 0.90, 95% CI: 0.11 to 7.28; I²=0%; 2 NRSs; 551 participants; very low CoE) and major adverse events (RR 0.48, 95% CI: 0.30 to 0.79; I²=0%; 10 NRS; 2,360 participants; very low CoE). CONCLUSIONS: While TE appears to have similar effects on short term postoperative residual renal function, there were uncertainties on mortality and major adverse events. However, we need rigorous RCTs to elucidate the effects of TE as the evidence stems mostly from NRSs.

Effect of the symptom-based alpha-blocker treatment on lower urinary tract symptoms in women: systematic review and meta-analysis.

AIMS: The aim of this study was to evaluate the effects of alpha blockers in women with lower urinary tract symptoms. METHODS: We conducted systematic review and meta-analysis on published a priori protocols. We searched multiple data sources for published and unpublished randomized controlled trials in any language. Primary outcomes included urologic symptom scores, quality of life, and overall adverse events. We performed meta-analysis using RevMan 5.3 and rated the certainty of evidence using Grading of Recommendations, Assessment, Development, and Evaluation. RESULTS: Alpha blockers likely reduced urological symptom score (mean difference: -1.50, 95% confidence interval: -2.91 to -0.09; moderate certainty of evidence). Alpha blockers may improve quality of life (standardized mean difference: -0.35, 95% confidence interval: -0.85 to 0.15; low certainty of evidence) and have little to no difference in overall adverse events (risk ratio: 1.09, 95% confidence interval: 0.55 to 2.15; low certainty of evidence). Based on five studies comparing combination therapy with alpha blockers and anticholinergics to anticholinergic monotherapy, combination therapy likely results in little to no difference in urological symptom score (mean difference: -0.35, 95% confidence interval: -1.98 to 1.27; moderate certainty of evidence) and quality of life (mean difference: -0.11, 95% confidence interval: -0.48 to 0.27; moderate certainty of evidence). We are very uncertain about the effect of combination therapy on overall adverse events (risk ratio: 1.07, 95% confidence interval: 0.40 to 2.84; very low certainty of evidence). CONCLUSION: Alpha blocker monotherapy for the women with lower urinary tract symptoms regardless of the underlying cause likely has satisfactory efficacy compared with placebo. However, combination therapy with anticholinergics likely has no additional effect on urologic symptom score and quality of life compared with anticholinergic monotherapy.

Lessons learned from clinical outcome and tumor features of patients underwent selective artery embolization due to postoperative bleeding following 2076 partial nephrectomies: propensity scoring matched study.

PURPOSE: To evaluate the clinical and tumor characteristics in patients undergoing selective artery embolization (SAE) for bleeding after partial nephrectomy (PN). METHODS: We retrospectively evaluated patients who underwent SAE from 2076 patients who underwent PN. The clinical and tumor characteristics of these patients were analyzed using entire data and propensity score matching (PSM). 76 patients who underwent PN (control, n = 38 patients; SAE, n = 38) were enrolled in PSM. RESULTS: SAE was performed in 41 patients who underwent open (19/1171), laparoscopic (4/60), and robot-assisted PN (18/845). The median period from PN to SAE was 12 days (interquartile range 8-24 day). The most common symptom of 31 (75.61%) patients was gross hematuria, followed by flank pain (3/41). Follow-up imaging revealed large pseudoaneurysm in 7 asymptomatic patients. The main reason for SAE on angiography was pseudoaneurysm (32/41), followed by arteriovenous fistula (5/41). Technical and clinical success was achieved in all patients. There was no statistical difference in the estimated glomerular filtration rate after 1 year, surgical methods, or baseline characteristics between the two groups. Conversely, there was statistically significant difference in ischemic time in the entire data and PSM. In the embolization group, renal masses showed statistically significant endophytic (p = 0.006) and posterior (p = 0.028) characteristics. CONCLUSIONS: SAE is an effective method for controlling postoperative bleeding while preserving renal function after PN. And, we suggest more attentive postoperative surveillance about vascular complications in patients with longer ischemia time or renal masses with endophytic and posterior locations.

Robot-Assisted Partial Nephrectomy for Totally Endophytic Renal Tumors: Step by Step Standardized Surgical Technique and Long-Term Outcomes with a Median 59-Month Follow-Up.

BACKGROUND: Treatment of totally endophytic renal tumors is a technically demanding surgery. While few studies show promising perioperative and short-term outcomes of robot-assisted partial nephrectomy (RAPN), its long-term outcomes remain undetermined. MATERIALS AND METHODS: A retrospective analysis of 89 patients with totally endophytic renal tumors undergoing either RAPN (n = 52) or open partial nephrectomy (OPN; n = 37) in a tertiary-care institution between 2005 and 2015 was performed. Primary endpoint was to describe our transperitoneal RAPN surgical technique, while secondary endpoint was to compare the 5-year chronic kidney disease (CKD)-free survival, cancer-specific survival (CSS), and metastasis-free survival (MFS) rates between RAPN and OPN. RESULTS: The median follow-up was 59 and 53 months for RAPN and OPN, respectively. Apart from increased prevalence of high complex tumors among RAPN cases (RAPN, 38.5% versus OPN, 16.2%; P = .037), and lower median eGFR (RAPN, 86 versus OPN 96 mL/minute/1.73 m2; P = .032), the remaining demographic characteristics were similar between the groups. At latest follow-up, the rates of local recurrence (P = .577), distant metastasis (P = .854), and cancer death (P = .187), and CKD upstaging ≥stage 3 (P = .728) did not differ between groups. The 5-year CKD upstaging-free survival was 96.2% versus 94.6% (log-rank, P = .746), MFS was 95.8% versus 97.1% (P = .876), and CSS was 100% versus 93.8% (log-rank, P = .102) when stratified by RAPN and OPN, respectively. CONCLUSION: RAPN is a safe and feasible option for treatment of totally endophytic renal tumors. Despite the increased prevalence of high tumor complexity and lower baseline renal function in the RAPN group, it achieved equivalent long-term oncologic control and functional outcome compared to OPN.

Predictors of biochemical recurrence after Retzius-sparing robot-assisted radical prostatectomy: Analysis of 359 cases with a median follow-up period of 26 months.

OBJECTIVES: Our aim was to evaluate the predictors of biochemical recurrence after Retzius-sparing robot-assisted radical prostatectomy. METHODS: The study cohort consisted of 359 consecutive non-metastatic prostate cancer patients who underwent Retzius-sparing robot-assisted radical prostatectomy between November 2012 and January 2016. According to the National Comprehensive Cancer Network prostate cancer risk classification, 164 patients (45.7%) had high- or very high-risk prostate cancer. No patient received adjuvant therapy until documented biochemical recurrence. Biochemical recurrence-free survival was estimated using the Kaplan-Meier method. Univariable and multivariable Cox proportional hazards regression models were used to determine variables predictive of biochemical recurrence. RESULTS: The median follow-up period was 26 months (interquartile range 19-38 months). The overall biochemical recurrence rate was 14.8%, and the median time to biochemical recurrence was 11 months (interquartile range 6-22 months). The 3-year biochemical recurrence-free survival probability was 71.2%, 72.1%, 88.7%, 82.3% and 95.7% in very high-, high-, intermediate-, low- and very low-risk prostate cancer, respectively (log-rank, P < 0.001). On multivariable analysis, preoperative prostate-specific antigen (hazard ratio 1.03, 95% confidence interval 1.02-1.04; P < 0.0001), percentage of maximum core involvement on biopsy (hazard ratio 1.02, 95% confidence interval 1.01-1.03; P = 0.029) and clinical stage ≥T3a (hazard ratio 2.12, 95% confidence interval 1.02-4.39; P = 0.043) were predictors of biochemical recurrence, whereas pathological Gleason score ≥8 (hazard ratio 5.63, 95% confidence interval 1.62-19.61; P = 0.007) and pathological tumor volume (hazard ratio 1.08, 95% confidence interval 1.04-1.20; P < 0.001) were the main pathological predictors of biochemical recurrence. CONCLUSIONS: Retzius-sparing robot-assisted radical prostatectomy confers effective biochemical recurrence control at the mid-term follow-up period. Preoperative prostate-specific antigen, advanced clinical stage and higher Gleason score were important predictors of biochemical recurrence after Retzius-sparing robot-assisted radical prostatectomy. Long-term oncological safety still needs to be established.

Yonsei nomogram: A predictive model of new-onset chronic kidney disease after on-clamp partial nephrectomy in patients with T1 renal tumors.

OBJECTIVES: To develop a predictive nomogram for chronic kidney disease-free survival probability in the long term after partial nephrectomy. METHODS: A retrospective analysis was carried out of 698 patients with T1 renal tumors undergoing partial nephrectomy at a tertiary academic institution. A multivariable Cox regression analysis was carried out based on parameters proven to have an impact on postoperative renal function. Patients with incomplete data, <12 months follow up and preoperative chronic kidney disease stage III or greater were excluded. The study end-points were to identify independent risk factors for new-onset chronic kidney disease development, as well as to construct a predictive model for chronic kidney disease-free survival probability after partial nephrectomy. RESULTS: The median age was 52 years, median tumor size was 2.5 cm and mean warm ischemia time was 28 min. A total of 91 patients (13.1%) developed new-onset chronic kidney disease at a median follow up of 60 months. The chronic kidney disease-free survival rates at 1, 3, 5 and 10 year were 97.1%, 94.4%, 85.3% and 70.6%, respectively. On multivariable Cox regression analysis, age (1.041, P = 0.001), male sex (hazard ratio 1.653, P < 0.001), diabetes mellitus (hazard ratio 1.921, P = 0.046), tumor size (hazard ratio 1.331, P < 0.001) and preoperative estimated glomerular filtration rate (hazard ratio 0.937, P < 0.001) were independent predictors for new-onset chronic kidney disease. The C-index for chronic kidney disease-free survival was 0.853 (95% confidence interval 0.815-0.895). CONCLUSION: We developed a novel nomogram for predicting the 5-year chronic kidney disease-free survival probability after on-clamp partial nephrectomy. This model might have an important role in partial nephrectomy decision-making and follow-up plan after surgery. External validation of our nomogram in a larger cohort of patients should be considered.

Estimated glomerular filtration rate's time to nadir after robot-assisted partial nephrectomy: Predictors and clinical significance on renal functional recovery.

OBJECTIVES: To investigate the impact of postoperative time to nadir of estimated glomerular filtration rate on renal functional changes after robot-assisted partial nephrectomy. METHODS: From 2006 to 2015, 287 patients with renal mass who underwent robot-assisted partial nephrectomy in a referral center were analyzed. The cohort was evaluated based on their time to develop nadir: group 1 (no nadir), group 2 (<48 h) and group 3 (≥48 h). The outcome measures were to evaluate the renal function recovery between groups, risk factors for development of nadir ≥48 h, as well as predictors of chronic kidney disease upstaging. RESULTS: The mean estimated glomerular filtration rate percentage change was the worst in group 3 compared with groups 1 and 2, with 13.8%, -0.67% and 8%, respectively (P < 0.001). Chronic kidney disease upstaging was more common in group 3 compared with the other groups (P < 0.001). Age, tumor size, PADUA score and warm ischemia time were predictors of developing ≥48 h estimated glomerular filtration rate nadir (odds ratio 1.04, P = 0.002; odds ratio 1.43, P < 0.001; odds ratio 1.24, P = 0.018; odds ratio 1.05, P < 0.001), respectively. The 5-year probability of freedom from chronic kidney disease upstaging was lower in group 3 (75.6%) compared with the other groups - 88.1% and 100% (P = 0.003). Time to nadir ≥48 h was a predictor of chronic kidney disease upstaging (odds ratio 3.02, P = 0.022). CONCLUSIONS: A continuous decline in estimated glomerular filtration rate (≥48 h) after partial nephrectomy is associated with increased risk of poor functional recovery overtime. Age, tumor size, PADUA score and warm ischemia time are independent predictors of developing ≥48 h time to nadir of estimated glomerular filtration rate. This higher risk subgroup should be targeted for stricter follow up to allow early detection of future risk of renal functional decline.

Novel robotic systems and future directions.

Robot-assistance is increasingly used in surgical practice. We performed a nonsystematic literature review using PubMed/MEDLINE and Google for robotic surgical systems and compiled information on their current status. We also used this information to predict future about the direction of robotic systems based on various robotic systems currently being developed. Currently, various modifications are being made in the consoles, robotic arms, cameras, handles and instruments, and other specific functions (haptic feedback and eye tracking) that make up the robotic surgery system. In addition, research for automated surgery is actively being carried out. The development of future robots will be directed to decrease the number of incisions and improve precision. With the advent of artificial intelligence, a more practical form of robotic surgery system can be introduced and will ultimately lead to the development of automated robotic surgery system.

Functional and oncological outcomes of open, laparoscopic and robot-assisted partial nephrectomy: a multicentre comparative matched-pair analyses with a median of 5 years' follow-up.

OBJECTIVES: To compare outcomes at a 5-year median follow-up among different partial nephrectomy (PN) approaches: robot-assisted (RAPN), laparoscopic (LPN) and open partial nephrectomy (OPN). PATIENTS AND METHODS: We retrospectively analysed 1 308 patients who underwent PN (RAPN, n = 380; LPN, n = 206; OPN, n = 722) between 2006 and 2012 at one of four academic centres. We performed 1:1:1 propensity-score-matching adjustment based on confounding variables among groups, and 366 patients (122 in each group) were included in the final analysis. Survival rates were analysed using the Kaplan-Meier method. RESULTS: The median follow-up periods were 60, 59.8 and 64.1 months for RAPN, LPN and OPN, respectively. In the matched groups, RAPN resulted in significantly lower mean estimated blood loss compared with LPN (P = 0.025) and OPN (P = 0.040), while LPN was associated with a longer mean operating time compared with RAPN (P = 0.001) and OPN (P = 0.001). The hospital stay was shorter in the RAPN group (P = 0.008). Regarding the oncological outcomes, there were no significant differences among the three groups in local recurrence rate (P = 0.882), distant metastasis rate (P = 0.816) or deaths from cancer (P = 0.779). At latest follow-up, the incidence of chronic kidney disease (CKD) upstaging was significantly lower in RAPN compared with LPN (20.55% vs 32%; P = 0.035) and OPN (20.5% vs 33.6%; P = 0.038). The 5-year CKD free-survival rate was significantly higher (78.4%) in the RAPN group compared with 58.8% and 65.8% in the LPN and OPN groups, respectively (log-rank P = 0.031). CONCLUSIONS: In the present study, RAPN, LPN and OPN had similar local recurrence, distant metastasis and cancer-related death rates at a 5-year median follow-up. In terms of functional outcomes, RAPN was associated with a lower incidence of CKD upstaging compared with OPN and LPN.

Retzius-sparing robot-assisted radical prostatectomy using the Revo-i robotic surgical system: surgical technique and results of the first human trial.

OBJECTIVE: To evaluate the safety and proficiency of the Revo-i® robotic platform (Meere Company Inc.) in the treatment of prostate cancer (PCa). PATIENTS AND METHODS: A prospective study was carried out on 17 patients with clinically localized PCa treated between 17 August 2016 and 23 February 2017 at our urology department using the Revo-i. Patients underwent Retzius-sparing robot-assisted radical prostatectomy (RS-RARP). The primary objective was to describe the RS-RARP step-by-step surgical technique using the Revo-i. In addition, the safety of the Revo-i was assessed according to intra-operative and the postoperative complications within 30 days of surgery. Early oncological outcomes were also assessed according to surgical margin status and biochemical recurrence (BCR). Continence was defined as use of no or only one pad. Surgeons' satisfaction with the Revo-i was assessed using the Likert scale. RESULTS: All surgeries were completed successfully, with no conversion to open or laparoscopic surgery. The median patient age was 72 years. The median docking time, console time, urethrovesical anastomosis time and estimated blood loss were 8 min, 92 min, 26 min and 200 mL, respectively. One patient was transfused intra-operatively as a result of blood loss of 1 500 mL. Postoperatively, two patients received blood transfusion, and there were no other serious/major complications. The median hospital stay was 4 days. At 3 months, four patients had positive surgical margins, one patient had BCR, and 15 patients were continent. Most of surgeons were satisfied with the Revo-i performance. CONCLUSIONS: The first human study for the treatment of patients with localized PCa using the Revo-i robotic surgical system was carried out successfully. The peri-operative, early oncological and continence outcomes are encouraging. Further prospective studies are warranted to support our preliminary results.

Does robot-assisted radical prostatectomy benefit patients with prostate cancer and bone oligometastases?

OBJECTIVE: To investigate the peri-operative and oncological outcomes of robot-assisted radical prostatectomy (RARP) in patients with oligometastatic prostate cancer (PCa). PATIENTS AND METHODS: We retrospectively reviewed the records of 79 patients with oligometastatic PCa treated with RARP or androgen deprivation therapy (ADT) between 2005 and 2015 at our institution. Of these 79 patients, 38 were treated with RARP and 41 were treated with ADT without local therapy. Oligometastatic disease was defined as the presence of five or fewer hot spots detected by preoperative bone scan. We evaluated peri-operative outcomes, progression-free survival (PFS), and cancer-specific survival (CSS). We analysed data using Kaplan-Meier methods, with log-rank tests and multivariate Cox regression models. RESULTS: Patients treated with RARP experienced similar postoperative complications to those previously reported in RP-treated patients, and fewer urinary complications than ADT-treated patients. PFS and CSS were longer in RARP-treated compared with ADT-treated patients (median PFS: 75 vs 28 months, P = 0.008; median CSS: not reached vs 40 months, P = 0.002). Multivariate analysis further identified RARP as a significant predictor of PFS and CSS (PFS: hazard ratio [HR] 0.388, P = 0.003; CSS: HR 0.264, P = 0.004). CONCLUSIONS: We showed that RARP in the setting of oligometastatic PCa is a safe and feasible procedure which improves oncological outcomes in terms of PFS and CSS. In addition, our data suggest that RARP effectively prevents urinary tract complications from PCa. The study highlights results from expert surgeons and highly selected patients that cannot be extrapolated to all patients with oligometastatic PCa; to confirm our findings, large, prospective, multicentre studies are required.

Off-Clamp Robot-Assisted Partial Nephrectomy: How Far Shall We Proceed?

BACKGROUND: Off-clamp robot-assisted partial nephrectomy (RAPN) is associated with increased intraoperative blood loss compared with on-clamp technique. Our aim was to demonstrate our surgical technique and to determine which tumors are ideally suited for this technique. METHODS: Sixty-two patients who underwent off-clamp RAPN for renal tumor between 2006 and 2016 were retrospectively analyzed. Increased estimated blood loss (EBL) volume was defined as more than 75 percentile. receiver operating characteristic (ROC) analysis was used to determine exact cut-off tumor size and the preoperative aspects and dimensions used for an anatomical (PADUA) score that are associated with increased EBL. Risk factors for increased EBL >400 mL and chronic kidney disease (CKD) upstaging were evaluated using logistic regression analysis. RESULTS: The median follow-up period was 20 months (interquartile range [IQR]: 12-84). Patient's mean age, mean tumor size, and mean body mass index were 53.5 ± 12.2 years, 2.6 ± 1.5 cm, and 25 ± 4.1 kg/m2, respectively. Median EBL volume was 200 mL (IQR: 100-400). ROC analysis showed that tumor size of 3.2 cm (area under the curve [AUC] = 0.82, P < .001) and PADUA score of 9 (AUC = 0.79, P = .001) were cut-off values for increased EBL >400 mL. Patients with tumor size >3.2 cm had longer operative time (116 versus 163 minutes, P = .002), more EBL (150 versus 575 mL, P < .001), and higher blood transfusion rate (0% versus 18.8%, P = .015), with increased tendency of conversion to radical nephrectomy (0% versus 12.5%, P = .063) compared with tumor size ≤3.2 cm. Overall CKD upstaging was present in 22 patients (35.4%). Multivariable logistic regression analysis showed that EBL >400 mL was the only predictor of CKD upstaging (odds ratio: 6.704, P = .009). CONCLUSIONS: Our study showed that the risk of intraoperative bleeding and transfusion rate during off-clamp RAPN is increased if tumor size >3.2 cm and/or PADUA complexity score ≥9. Moreover, EBL >400 mL was a risk factor of CKD upstaging, despite zero ischemia. Further larger prospective studies are warranted to validate our results.

Robotic nurse duties in the urology operative room: 11 years of experience.

The robotic nurse plays an essential role in a successful robotic surgery. As part of the robotic surgical team, the robotic nurse must demonstrate a high level of professional knowledge, and be an expert in robotic technology and dealing with robotic malfunctions. Each one of the robotic nursing team "nurse coordinator, scrub-nurse and circulating-nurse" has a certain job description to ensure maximum patient's safety and robotic surgical efficiency. Well-structured training programs should be offered to the robotic nurse to be well prepared, feel confident, and maintain high-quality of care.

Impact of Pretreatment Hydronephrosis on the Success Rate of Shock Wave Lithotripsy in Patients with Ureteral Stone.

PURPOSE: To evaluate predictors of the success rate for one session of shock wave lithotripsy (SWL), focusing on the relationships between pretreatment hydronephrosis grade and one-session SWL success rates. MATERIALS AND METHODS: The medical records of 1824 consecutive patients who underwent an initial session of SWL for treatment of urinary stones between 2005 and 2013 were reviewed. After exclusion, 700 patients with a single, 4-20 mm diameter radiopaque calculus were included in the study. RESULTS: The mean maximal stone length (MSL) and skin-to-stone distance were 9.2±3.9 and 110.8±18.9 mm, respectively. The average values for mean stone density (MSD) and stone heterogeneity index (SHI) were 707.0±272.1 and 244.9±110.1, respectively. One-session success rates were 68.4, 75.0, 75.1, 54.0, and 10.5% in patients with hydronephrosis grade 0, 1, 2, 3, and 4, respectively. Patients were classified into success or failure groups based on SWL outcome. Multivariate logistic regression analyses revealed that MSL [odds ratio (OR) 0.888, 95% confidence intervals (CI): 0.841-0.934, p<0.001], MSD (OR 0.996, 95% CI: 0.995-0.997, p<0.001), SHI (OR 1.007, 95% CI: 1.005-1.010, p<0.001), and pretreatment hydronephrosis grade (OR 0.601, 95% CI: 0.368-0.988, p=0.043) were significantly associated with one-session success. CONCLUSION: Pretreatment grades 3 or 4 hydronephrosis were associated with failure of SWL in patients with a single ureteral stone. In the presence of severe hydronephrosis, especially hydronephrosis grade 4; physicians should proceed cautiously in choosing and offering SWL as the primary treatment for ureteral stone.