Comparison of Fragmentation and Dusting Laser Modes for Laser Ureteroscopy Lithotripsy of Ureteral Stones at a Single Center

Background Laser ureteroscopic lithotripsy (URSL) is an efficacious treatment for ureteral stones. There have been few previous studies compared the different energy and frequency settings for URSL in a single center. The fragmentation and dusting laser mode were simultaneously used in our medical center. We compared the efficacy and outcomes of these two laser modalities for the treatment of ureteral stones.Methods Patients who underwent fragmentation or dusting laser URSL for ureteral stones were retrospectively reviewed. The demographic data, stone parameters, perioperative data and stone-free rates were analyzed between the two groups.Results There were a total of 421 patients with ureteral stones who met the study criteria. More patients in the dusting group had multiple ureteral stones and pyuria than in the fragmentation group. The fragmentation group had a better stone free rate and a lower push back rate compared with the dusting group. (82% vs. 71%; 10% vs. 20% respectively, both p<0.05). Multivariate analysis revealed that stone basket use (odds ratio [OR] = 3.026; p<0.001) significantly improved the stone free rate, whereas multiple stones (OR=0.322; p <0.001), upper ureteral stone location (OR=0.098; p=0.002) and pyuria (OR=0.428; p=0.001) significantly decreased the stone free rate. The laser mode used was not significantly related to the stone free rate in the multivariate analysis.Conclusions Both laser modes were effective and safe for ureteral lithotripsy. Risk factors associated with a lower stone free rate were multiple stones, pyuria, upper ureteral stone location and an operation without the use of a stone basket.

Development of prediction models of spontaneous ureteral stone passage through machine learning: Comparison with conventional statistical analysis

Objectives To develop a prediction model of spontaneous ureteral stone passage (SSP) using machine learning and logistic regression and compare the performance of the two models. Indications for management of ureteral stones are unclear, and the clinician determines whether to wait for SSP or perform active treatment, especially in well-controlled patients, to avoid unwanted complications. Therefore, suggesting the possibility of SSP would help make a clinical decision regarding ureteral stones. Methods Patients diagnosed with unilateral ureteral stones at our emergency department between August 2014 and September 2018 were included and underwent non-contrast-enhanced computed tomography 4 weeks from the first stone episode. Predictors of SSP were applied to build and validate the prediction model using multilayer perceptron (MLP) with the Keras framework. Results Of 833 patients, SSP was observed in 606 (72.7%). SSP rates were 68.2% and 75.6% for stone sizes 5–10 mm and <5 mm, respectively. Stone opacity, location, and whether it was the first ureteral stone episode were significant predictors of SSP. Areas under the curve (AUCs) for receiver operating characteristic (ROC) curves for MLP, and logistic regression were 0.859 and 0.847, respectively, for stones <5 mm, and 0.881 and 0.817, respectively, for 5–10 mm stones. Conclusion SSP prediction models were developed in patients with well-controlled unilateral ureteral stones; the performance of the models was good, especially in identifying SSP for 5–10-mm ureteral stones without definite treatment guidelines. To further improve the performance of these models, future studies should focus on using machine learning techniques in image analysis.

Ureteral stone with hydronephrosis and urolithiasis alone are risk factors for acute kidney injury in patients with urinary tract infection

To identify whether urolithiasis with or without hydronephrosis has an impact on acute kidney injury (AKI) in patients with urinary tract infection (UTI). This study aimed to identify whether urolithiasis with or without hydronephrosis has an impact on AKI in patients with UTI. This retrospective study enrolled hospitalized UTI patients who underwent imaging in an acute care setting from January 2006 to April 2019. Of the 1113 participants enrolled, 191 (17.2%) had urolithiasis and 76 (6.8%) had ureteral stone complicated with hydronephrosis. Multivariate logistic regression analysis showed that in UTI patients with urolithiasis, the presence of ureteral stone with concomitant hydronephrosis was an independent risk factor for AKI (odds ratio [OR] 2.299, 95% confidence interval [CI] 1.112–4.755, P = 0.025). In addition, urolithiasis was associated with an increased risk for AKI (OR 2.451, 95% CI 1.369–4.389, P = 0.003) in UTI patients without hydronephrosis. The presence of ureteral stone with hydronephrosis increases the risk for AKI of UTI patients with urolithiasis, and urolithiasis remains a risk factor of AKI in UTI patients without hydronephrosis.

Postrenal Azotemia in a Gastric Cancer Patient Revealed the Coincidence of Ureteral Metastasis and Contralateral Ureteral Stone: A Case Report

Metastatic ureteral masses are not rare, but isolated ureteral metastasis from the origin of gastric cancer is rare. Ureteral metastasis is usually unilateral and does not lead to postrenal azotemia unless in single kidney patients. Herein, we describe an 80-year-old man with a history of nonmetastatic gastric cancer who presented with postrenal azotemia due to the coincidence of right distal ureteral metastasis and left distal ureteral stone.

Outcomes of ureteral stent placement for hydronephrosis in patients with ureteral stone

BackgroundRoutine ureteral stent placement after ureteroscopy (URS) for ureteral stone treatment is arguable due to the possible stent-related symptoms. Several studies claimed that its use is necessary, while others reported that its use is excessive. Hydronephrosis occurs when urine cannot drain out from the kidney to the bladder due to blockage or obstruction. We aimed to evaluate the role of ureteral stents in hydronephrosis resolution in ureteral stone patients following URS lithotripsy. MethodsThis was a prospective observational study using secondary data involving 130 ureteral stone patients undergoing URS lithotripsy [99 patients (76.2%) with stent placement and 31 patients (23.8%) without stent]. Data consisting of baseline characteristics, pre-operative status, intraoperative characteristics, and postoperative complications were collected from the medical record database and presented descriptively. The patients were divided into two groups based on stent placement. Comparison of hydronephrosis resolution between the groups was analyzed with Chi-square. ResultsUreteral lesions were the most common indication of ureteral stent placement following URS lithotripsy (28.3%). The most bothersome symptoms were dysuria in 18 patients (18.2%); followed by frequency in eight patients (8.1%) and low back pain in six patients (6.1%). All symptoms were successfully treated with oral medications. There were 41 patients (91.1%) with pre-operative hydronephrosis significantly resolved after stent placement compared to 5 (62.5%) patients without stent placement (p=0.027). ConclusionUreteral stenting significantly resolves pre-operative hydronephrosis after URS lithotripsy in patients with ureteral stone. Ureteral stent placement is the preferred method for the treatment of pre-operative hydronephrosis.

Development and validation of a preoperative nomogram for predicting patients with impacted ureteral stone: a retrospective analysis

Background To develop and validate a practical nomogram for predicting the probability of patients with impacted ureteral stone. Methods Between June 2020 to March 2021, 214 single ureteral stones received ureteroscopy lithotripsy (URSL) were selected in development group. While 82 single ureteral stones received URSL between April 2021 to May 2021 were included in validation group. Independent factors for predicting impacted ureteral stone were screened by univariate and multivariate logistic regression analysis. The relationship between preoperative factors and stone impaction was modeled according to the regression coefficients. Discrimination and calibration were estimated by area under the receiver operating characteristic (AUROC) curve and calibration curve respectively. Clinical usefulness of the nomogram was evaluated by decision curve analysis. Results Age, ipsilateral stone treatment history, hydronephrosis and maximum ureteral wall thickness (UWTmax) at the portion of stone were identified as independent predictors for impacted stone. The AUROC curve of development and validation group were 0.915 and 0.882 respectively. Calibration curve of two groups showed strong concordance between the predicted and actual probabilities. Decision curve analysis showed that the predictive nomogram had a superior net benefit than UWTmax for all examined probabilities. Conclusions We developed and validated an individualized model to predict impacted ureteral stone prior to surgery. Through this prediction model, urologists can select an optimal treatment method and decrease intraoperative and postoperative complications for patients with impacted ureteral calculus.

Urinothorax, another complication of bladder tumor: case report

Background Rupture of the fornix is a rare and serious urological complication of obstructive pathologies. The main cause is ureteral stone, but rarely a bladder tumor. Described complications of fornix rupture are superinfection, perirenal abscesses and even sepsis, but not urinothorax. Case presentation Patient of 56 years old, active and chronic smoker, was hospitalized for anemia and obstructive renal failure on a non-documented bladder tumor; clinically, he was presented with hematuria and an intense right loin pain associated with homolateral basithoracic pain and dyspnea. The CT scan without injection showed a right perirenal collection with bilateral renal dilatation on endo-vesical tumor and a right pleural effusion of less abundance. The ratio of pleural fluid creatinine to blood creatinine was greater than 1, confirming urinothorax. As an emergency, a percutaneous nephrostomy was performed. After clinical stabilization, the patient underwent a trans-urethral resection of the bladder and derivation by a double j stent. The ultimate evolution was favorable. Conclusions Beyond the metabolic complications secondary to obstructions, mechanical complications, which can also be fatal, must be included.