[Two Cases of Ammonium Acid Urate Urinary Stones That Could Not Be Diagnosed by Dual-Energy Computed Tomography].

We report two cases of ammonium acid urate stones that could not be diagnosed by dual-energy computed tomography (CT). Case 1: A 37-year-old female was referred to our hospital for a left kidney stone. She had a medical history of anorexia nervosa, Basedow's disease and hypoparathyroidism. Her height was 167 cm, weight 38 kg and body mass index (BMI) 13. 6. CT showed a left kidney stone measuring 18×12 mm. Dual-energy CT showed that the left kidney stone was composed of uric acid. Chemolysis by oral administration of alkaline citrate was attempted. Six months later, CT showed no improvement, and endoscopic combined intrarenal surgery (ECIRS) was performed. Stone analysis revealed pure ammonium acid urate. Case 2: A 42-year-old female was referred to our hospital because of right back pain. She had a medical history of ventricular septal defect and urolithiasis. Her height was 158 cm, weight 37 kg, and BMI 14.8. CT showed a right kidney stone measuring 16×12 mm. Dual-energy CT showed that the right kidney stone was composed of uric acid. Chemolysis by oral administration of alkaline citrate was attempted. Two months later, CT showed no improvement, and ECIRS was performed. Stone analysis revealed pure ammonium acid urate. It is difficult to differentiate uric acid stones and ammonium acid urate stones by dual-energy CT. Even when dual-energy CT suggests uric acid stones, ammonium acid urate stones should also be considered in thin young women and women with a history of anorexia nervosa.

[Retrograde Ureteroscopic Lithotripsy with Ureteral Access Sheath Via Cutaneous Ureterostomy after Urinary Diversion : A Case Report].

A 65-year-old man presented with a history of rectal cancer 20 years prior that led to the development of a cutaneous ureterostomy and a colostomy. Subsequently, the patient was diagnosed with acute complicated pyelonephritis due to a right ureteral stone. After the placement of a single J ureteral stent in the right ureter for therapeutic management, the patient was referred to our institution for treatment of the right ureteral stone. An abdominal computed tomography (CT) revealed an 11×8 mm stone in the upper right ureter. A 10/12 Fr ureteral access sheath was inserted through the cutaneous ureterostomy and retrograde ureteroscopic lithotripsy was performed. Although a febrile urinary tract infection appeared postoperatively, the patient was discharged on the sixth postoperative day. At postoperative 1-month, CT showed no residual stones and no hydronephrosis. The use of a ureteral access sheath in performing retrograde ureteroscopic lithotripsy effectively managed the ureteral stone with cutaneous ureterostomy.

Ureteral stone volume and female gender predicts perioperative complications after complete ipsilateral upper urinary tract stone removal using flexible ureterorenoscopy.

PURPOSE: To identify the risk factors for perioperative complications to prevent perioperative complications after complete ipsilateral upper urinary stone removal using flexible ureterorenoscopy. MATERIALS AND METHODS: We retrospectively examined 111 patients who underwent flexible ureterorenoscopy for ipsilateral renal stones with a diameter ≥ 5 mm at the same time as ureterorenoscopy for ureteric stones. The flexible ureterorenoscopy procedures were performed following the fragmentation technique. Patients who experienced (complication group) and did not experience (non-complication group) perioperative complications were compared. The complication group included 33 patients with Clavien-Dindo classification scores of I, II, III, or IV and/or those with a body temperature of > 37.5 â„ƒ during hospitalization. RESULTS: The overall stone volume, stone-free rate and procedure duration were 1.71 mL, 96.4% and 77 min, respectively. The rate of perioperative complications was 29.7% (grade 1, 2 and 3 was 23.4%, 5.4% and 0.9%, respectively). Severe complications (Clavien-Dindo grade 4) were not observed. Multivariable analysis revealed that ureteral stone volume and female patients were independent predictors of perioperative complications after flexible ureterorenoscopy (p = 0.015 and 0.017, respectively). CONCLUSIONS: This study showed that ureteral stone volume and female gender have the possibility to increase perioperative complications. These preliminary data help to select for patients who are at low risk of complications. Therefore, in these selected patients, complete ipsilateral upper urinary tract stone removal using flexible ureterorenoscopy may reduce the recurrence of urolithiasis without increasing perioperative complications.

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.

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.

[A Study of Retrograde Ureteroscopic Lithotripsy with Ureteral Access Sheath for Urinary Calculus After Ileal Conduit Construction].

We retrospectively evaluated the safety and effectiveness of retrograde ureteroscopy via ileal conduit construction. Between January 2014 and December 2021, 5 patients (8 procedures) with ileal conduit construction received retrograde ureteroscopic lithotripsy with a 11/13 Fr ureteral access sheath. At postoperative 1 month, a plain computed tomography (CT) and kidney, ureter, and bladder X-ray (KUB) were performed to assess stone fragmentation and hydronephrosis. According to postoperative imaging, stone-free was defined as residual fragments of 4 mm or less on KUB and 2 mm or less on CT. The mean stone size was 11 mm (6-13 mm). The mean stone volume was 1. 51 ml (0.33-2.56 ml). The mean operative time was 91 min (60-133 min). SFR was 100% on KUB and 87.5% on CT. One procedure (12.5%) resulted in a postoperative fever greater than 38.5℃. There were no complications of grade III or higher according to the modified Clavien-Dindo classification. No exacerbation of hydronephrosis was observed on CT. Retrograde ureteroscopy with a ureteral access sheath was found to be effective for urolithiasis in patients with ileal conduit.

[Ureteral Access Sheath Assisted Percutaneous Antegrade Ureteroscopic Lithotripsy for Impacted Ureteral Calculus].

We retrospectively evaluated the safety and effectiveness of ureteral access sheath-assisted percutaneous antegrade ureteroscopic lithotripsy in treating ureteral calculus. Between January 2016 and April 2022, 28 patients with ureteral calculus received ureteral access sheath-assisted percutaneous antegrade ureteroscopic lithotripsy. At postoperative 1 month, a plain computed tomography (CT) and kidney ureter bladder X-ray (KUB) were performed to assess stone fragmentation and hydronephrosis. According to postoperative imaging, stone-free was defined as residual fragments 4 mm or less on KUB and 2 mm or less on CT. The mean stone size was 16.3 mm (3-43 mm). The mean stone volume was 1.91 ml (0.13-6.1 ml). The mean operative time was 140 min (60-222 min). Stone-free rate (SFR) was 89.3% on KUB, and 82.1% on CT. Three patients (10.7%) had postoperative fever greater than 38.5°C. There were no complications of grade III or higher according to the modified Clavien-Dindo classification. In the Ellenbogen classification, improvement was observed in hydronephrosis of Grade II or lower. Improvement was also observed in cases with Grade III hydronephrosis. However, due to the presence of residual renal atrophy, there was no change in the classification. The preoperative eGFR was 63 ml/min/1.73 m² (36-101 ml/min/1.73 m²) and the postoperative eGFR was not improved. We conclude that ureteral access sheath-assisted percutaneous antegrade ureteroscopic lithotripsy is effective for treating impacted ureteral calculus.

Japanese linguistic validation of the ureteral stent symptom questionnaire.

OBJECTIVE: We validated the Japanese version of the ureteral stent symptom questionnaire in patients with an indwelling ureteric stent. METHODS: The English version of the ureteral stent symptom questionnaire was translated into Japanese using a multistep process by three urologists and two independent translators. A total of 70 patients with indwelling ureteral stents completed the Japanese ureteral stent symptom questionnaire, as well as validated instruments, namely, the International Prostate Symptom Score or Overactive Bladder Symptom Score and the EuroQoL 5-dimension questionnaires. Patients completed questionnaires at 2 weeks after stent insertion and 4 weeks after stent removal. The second group included 87 healthy individuals who agreed to complete the questionnaires. The reliability of the Japanese version was evaluated for internal consistency using Cronbach's α test. Psychometric properties of the questionnaire were analyzed, and included convergent validity, sensitivity to change and discriminant validity. RESULTS: A total of 70 cases and 87 controls were suitable for the analysis. A comparison of patients with ureteric stents and healthy individuals was carried out, and the convergent validity determined by the correlation between other instruments and the corresponding ureteral stent symptoms questionnaire domains was satisfactory (P < 0.05). Internal consistencies (Cronbach's α coefficients 0.73-0.80) were satisfactory, except for the sexual matters domain. Test-retest reliability was good, except for the sexual matters domain (Spearman's coefficient 0.71-0.93). CONCLUSIONS: The Japanese version of the ureteral stent symptom questionnaire proved to be a reliable and robust instrument for the evaluation of ureteral stent-associated morbidity for both men and women.

Examining the Impact of Different Properties of Ureteral Access Sheaths in Reducing Insertion Force During Retrograde Intrarenal Surgery: An In Vitro Study.

Background and Purpose: This study aimed to evaluate the characteristics of ureteral access sheaths (UASs) that can reduce the insertion force while accessing the upper urinary tract. Materials and Methods: Six different types of 12/14F UASs were used. We evaluated the properties of UASs such as the diameter of the outer sheath, length of the inner dilator tip exposed from the outer sheath, sheath flexibility (assessed in terms of bending force of the tip or base), flexibility ratio (i.e., bending force value of tip-to-base ratio), and frictional force of the outer sheath surface. We measured the force required for inserting the UAS into an artificial ureteral model and examined the correlation between the relevant characteristics and insertion force for each UAS. Results: Overall, a lower tip-to-base flexibility ratio (r = 0.66) and a lower frictional force (r = 0.50) were inversely correlated with insertion force. The force of insertion into the bifurcation was associated with the flexibility of the base (r = -0.64), flexibility ratio (r = 0.79), and frictional force (r = 0.66). Moreover, a shorter dilator tip (r = 0.52), lower flexibility ratio (r = 0.52), and lower frictional force (r = 0.50) were correlated with a lower insertion force at the proximal ureter. Conclusion: A UAS with a rigid base and flexible tip parts, a smoother surface, and a shorter dilator tip would be preferable for reducing the insertion force. These findings may be crucial for selecting or developing an ideal UAS that can decrease the risk of ureteral injury.

Gap between UAS and ureteroscope predicts renal stone-free rate after flexible ureteroscopy with the fragmentation technique.

PURPOSE: To assess the effect of our new classification on surgical outcomes after flexible ureteroscopy (fURS) for kidney stones. METHODS: We retrospectively examined 128 patients after single renal fURS procedures performed using ureteral access sheaths (UASs) with the fragmentation technique. Based on the gap (calculated by subtracting the ureteroscope diameter from the UAS diameter), enrolled patients were divided into three groups: small (< 0.6 mm), medium (0.6 to < 1.2 mm), and large space groups (≥ 1.2 mm). Stone-free (SF) status was defined as either complete absence of stones (SF) or the presence of stones < 4 mm in diameter on non-contrast computed tomography (NCCT). RESULTS: The SF rate was significantly lower in the small space group (50% in small, 97.9% in medium, 89.2% in large; p = 0.001). Perioperative complications over Clavien-Dindo Grade I were observed in 16.7%, 4.2%, and 8.1% of patients, respectively (p = 0.452). The ratio of stone volume and operative time (efficiency of stone removal) was significantly higher in the large space group compared to the small and medium space groups (0.009 ± 0.003 ml/min, 0.013 ± 0.005 ml/min, 0.027 ± 0.012 ml/min, respectively; p < 0.001). CONCLUSION: Our findings that gaps > 0.6 mm (1.8 Fr), including the combination of a 9.5-Fr UAS and a small caliber ureteroscope, improve SF rates, and larger gaps facilitate stone removal efficiency providing the basis for future development of clinical protocols aimed at improving outcomes.

Minimally invasive versus standard endoscopic combined intrarenal surgery for renal stones: a retrospective pilot study analysis.

PURPOSE: The effect of combining miniaturization with endoscopic combined intrarenal surgery (ECIRS) is unclear. Thus, we compared the treatment outcomes between minimally invasive ECIRS (mini-ECIRS) using 16.5 Fr percutaneous access sheath and standard ECIRS using 24 Fr access sheath for renal stones MATERIALS AND METHODS: We retrospectively analyzed consecutive patients who underwent single session mini or standard-ECIRS in the modified Valdivia position for renal stones between April 2009 and May 2016. To adjust for patient characteristics, 77 pairs were matched using preoperative parameters including age, sex, history of febrile urinary tract infection (UTI), stone surface area, number of involved calyces, and staghorn calculi. RESULTS: The stone free rate (SFR) was similar between mini and standard ECIRS according to non-contrast computed tomography (61.1% vs. 52.0%, p = 0.388). The rate of perioperative complications exceeding grade 2 based on the Clavien-Dindo classification was similar in both groups (19.5% vs. 26.0%, p = 0.442). Severe complications exceeding grade 3 were also similar in both groups (2.6% vs. 3.9%, p > 0.99). Two cases of septic shock were noted in each group. Although there was no difference regarding bleeding-related complications (2.6% vs. 6.5%, p = 0.442), pseudoaneurysm or blood transfusion was not observed in the mini-ECIRS group. Pain visual analog scale values in the perioperative period were lower in the mini-ECIRS group (1.34 ± 1.08 vs. 1.69 ± 1.23, p = 0.062). CONCLUSIONS: This study demonstrated that, compared to standard ECIRS, mini-ECIRS maintained SFR without increasing perioperative complications, tended to reduce postoperative pain and had a potential to reduce bleeding-related complications. This report suggests the advantages of ECIRS miniaturization for renal stones.

A Novel Flexible Ureteroscope with Omnidirectional Bending Tip Using Joystick-Type Control Unit (URF-Y0016): Initial Validation Study in Bench Models.

Purpose: The conventional flexible ureteroscope has limited access into the lower calix and often causes biomechanical stress to surgeons. Recently, a novel flexible ureteroscope with an omnidirectional bending tip with a joystick-type control unit (URF-Y0016; Olympus, Japan) was developed. We verified the operability and ergonomics of the URF-Y0016 compared with that of the conventional flexible ureteroscope (URF-P6) in bench models. Materials and Methods: Twenty-five medical students with no experience in performing ureteroscopic manipulation were randomly assigned to URF-Y0016 and URF-P6 leading groups in a crossover study. The task was performed using a simple model as an exploratory experiment and an artificial kidney model as an evaluation experiment. We compared the task completion times of both groups, while the factors influencing task completion time were entered into a multivariate model. The ergonomics of endourology were compared using a validated questionnaire. Results: The task completion time in the URF-Y0016 group was significantly shorter than in the URF-P6 group (p < 0.001). The URF-Y0016 group showed no difference in task completion time between each renal calix, whereas in the URF-P6 group the task completion time in the lower calix was significantly longer than that in other calices (p < 0.001). In multivariate analysis, the model of flexible ureteroscope used significantly influenced the task completion time (p < 0.001). The ergonomics of the URF-Y0016 group were significantly better than those of the URF-P6 group (p = 0.001). Conclusions: URF-Y0016 may offer benefits in ureteroscopy performance over the conventional flexible ureteroscope.

Development and internal validation of a nomogram to predict perioperative complications after flexible ureteroscopy for renal stones in overnight ureteral catheterization cases.

PURPOSE: To identify risk factors by developing and internally validating a nomogram for preventing perioperative complications in overnight ureteral catheterization cases after fURS for kidney stones. METHODS: We retrospectively examined 309 patients with overnight ureteral catheterization after single fURS procedures for renal stones. fURS procedures were performed based on the fragmentation technique. The ureteral catheter was removed on postoperative day 1. Within this group, patients who experienced perioperative complications (complication group) were compared with those who did not experience complications (non-complication group). The complication group included 77 patients whose Clavien-Dindo classification score was I, II, III, or IV and/or those whose body temperature during hospitalization was over 37.5 °C. RESULTS: The overall stone volume, stone-free rate, incidence of perioperative complications, and procedure duration were 1.39 mL, 94.8%, 24.9%, and 62 min, respectively. Severe complications of a Clavien-Dindo level III or IV were observed in only four cases (1.3%). Multivariate assessment revealed five independent predictors of perioperative complications after fURS with overnight catheterization: age (p = 0.11), sex (p = 0.067), stone volume (p = 0.33), Hounsfield units (p = 0.16), and narrow ureter (p = 0.018). We developed a nomogram to predict perioperative complications after fURS using these parameters. CONCLUSIONS: We developed a predictive model for perioperative complications of patients with overnight catheterization after fURS for renal stones. This model could select patients who were at a low risk of complications.

Comparison of Outcomes between Two Methods to Extract Stone Fragments during Flexible Ureteroscopic Lithotripsy.

OBJECTIVES: To retrospectively compare the operative and clinical outcomes of flexible ureteroscopic lithotripsy (fURSL) with stone extraction performed either by a surgeon (SE) who manipulates the retrieval basket or by having the surgical assistant (AE) manipulate the retrieval basket with the aim of clarifying which method provides a greater stone-free postoperative status. METHODS: The study group consisted of patients who underwent fURSL with SE or AE at our institution between April 2015 and December 2016. Demographic, clinical, stone, and operative variables were compared between the two groups. Multivariate logistic regression was used to identify risk factors associated with a stone-free and non-stone-free status postoperatively. RESULTS: Our analysis included 196 cases of renal stones treated using fURSL, with 109 who underwent AE and 87 who underwent SE. The rate of stone-free status was higher for the SE group (90.8%) than for the AE group (61.5%; P < 0.001). The method of extraction was identified as an independent predictor of stone-free status (P < 0.001, odds ratio (SE compared to AE), 9.133, 95% confidence interval, 3.736-22.322). CONCLUSION: The stone-free rate is improved by having the surgeon perform the stone extraction as part of the fURSL procedure.

Outcome of flexible ureteroscopy for renal stone with overnight ureteral catheterization: a propensity score-matching analysis.

PURPOSE: To evaluate the influence of overnight ureteral catheterization and determine if routine long-term post-stenting can be avoided in flexible ureterorenoscopy (fURS) procedure for kidney stone. METHODS: Three hundred ninety-three patients who underwent single fURS for kidney stone between January 2013 and June 2016 at a single institute were retrospectively analyzed. The stone-free (SF) and perioperative complication rates in patients with routine long-term post-stenting after fURS (long-term stent group) were compared with those of patients with overnight ureteral catheterization (short-term stent group). Propensity score-matching analysis was used to adjust the difference in baseline preoperative parameters between the two groups. All preoperative parameters were chosen to develop the propensity score, and 74 patients in the short-term stent group were retrospectively matched with the patients in the long-term stent group at a 1:1 ratio. RESULTS: Patient characteristics included age, sex, side of involvement, height, body weight, body mass index, number of stone(s), stone volume, Hounsfield units of stone, preoperative white blood cell count, preoperative C-reactive protein, preoperative creatinine, pretreatment, pre-stenting, stenosis of the ureter, and procedure duration. The SF rates were 91.9 and 93.2% in the short-term and long-term stent groups, respectively. Perioperative complications were 14.9 and 12.2%. No difference was noted between the two groups in terms of SF and perioperative complication rates. CONCLUSIONS: Short-term post-stenting using overnight ureteral catheterization in uncomplicated cases after fURS for kidney stone was as effective as conventional long-term post-stenting in reducing postoperative complications. These preliminary data suggest the possibility that routine long-term post-stenting was unnecessary.

A new prediction model for operative time of flexible ureteroscopy with lithotripsy for the treatment of renal stones.

This study aimed to develop a prediction model for the operative time of flexible ureteroscopy (fURS) for renal stones. We retrospectively evaluated patients with renal stones who had been treated successfully and had stone-free status determined by non-contrast computed tomography (NCCT) 3 months after fURS and holmium laser lithotripsy between December 2009 and September 2014 at a single institute. Correlations between possible factors and the operative time were analyzed using Spearman's correlation coefficients and a multivariate linear regression model. The P value < 0.1 was used for entry of variables into the model and for keeping the variables in the model. Internal validation was performed using 10,000 bootstrap resamples. Flexible URS was performed in 472 patients, and 316 patients were considered to have stone-free status and were enrolled in this study. Spearman's correlation coefficients showed a significant positive relationship between the operation time and stone volume (ρ = 0.417, p < 0.001), and between the operation time and maximum Hounsfield units (ρ = 0.323, p < 0.001). A multivariate assessment with forced entry and stepwise selection revealed six factors to predict the operative time of fURS: preoperative stenting, stone volume, maximum Hounsfield unit, surgeon experience, sex, and sheath diameter. Based on this finding, we developed a model to predict operative time of fURS. The coefficient of determination (R2) in this model was 0.319; the mean R2 value for the prediction model was 0.320 ± 0.049. To our knowledge, this is the first report of a model for predicting the operative time of fURS treatment of renal stones. The model may be used to reliably predict operative time preoperatively based on patient characteristics and the surgeons' experience, plan staged URS, and avoid surgical complications.

Effect of Amplatz Sheath on Cystolithotripsy for Women with Large Bladder Stone.

OBJECTIVE: This study compared the effect of endourological procedures with or without the Amplatz sheath (AS) on cystolithotripsy. METHODS: We retrospectively analysed 18 patients who underwent treatment for bladder stone over 30 mm. This study consisted of two groups, namely, patients who underwent cystolithotripsy with an AS (AS group) and those who underwent standard procedure without an AS (SP group). The stone-free rate, total energy used for operation, operation time, days of admission after operation, and complication of both groups were compared. RESULTS: The number of patients in the AS and SP groups was 10 and 8, respectively. Significant differences were not found between these two groups with regard to age, stone burden, stone volume, number of stones, and history of neurogenic bladder. All patients in both groups achieved a stone-free state. Total energy was significantly increased and operation time was shorter in the AS group. No significant difference was observed in terms of days of admission after operation. Any complications were not increased by the use of AS. Struvite was the most common stone component in both groups. CONCLUSION: Use of an AS can shorten the operation time of cystolithotripsy without increasing perioperative complication.

Developing a preoperative predictive model for ureteral length for ureteral stent insertion.

BACKGROUND: Ureteral stenting has been a fundamental part of various urological procedures. Selecting a ureteral stent of optimal length is important for decreasing the incidence of stent migration and complications. The aim of the present study was to develop and internally validate a model for predicting the ureteral length for ureteral stent insertion. METHODS: This study included a total of 127 patients whose ureters had previously been assessed by both intravenous urography (IVU) and CT scan. The actual ureteral length was determined by direct measurement using a 5-Fr ureteral catheter. Multiple linear regression analysis with backward selection was used to model the relationship between the factors analyzed and actual ureteral length. Bootstrapping was used to internally validate the predictive model. RESULTS: Patients all of whom had stone disease included 76 men (59.8%) and 51 women (40.2%), with the median and mean (± SD) ages of 60 and 58.7 (±14.2) years. In these patients, 53 (41.7%) right and 74 (58.3%) left ureters were analyzed. The median and mean (± SD) actual ureteral lengths were 24.0 and 23.3 (±2.0) cm, respectively. Using the bootstrap methods for internal validation, the correlation coefficient (R2) was 0.57 ± 0.07. CONCLUSION: We have developed a predictive model, for the first time, which predicts ureteral length using the following five preoperative characteristics: age, side, sex, IVU measurement, and CT calculation. This predictive model can be used to reliably predict ureteral length based on clinical and radiological factors and may thus be a useful tool to help determining the optimal length of ureteral stent.

[A Case of Endoscopic Combined Intrarenal Surgery for Multiple Encrusted Stones on a Forgotten Ureteral Stent Left for 4 Years].

A 43-year-old man underwent extracorporeal shock wave lithotripsy (ESWL) for a left ureteral stone and implantation of a loop stent for the treatment of stone pain in February 2011. However, he was lost to follow-up before the complete removal of the stones and stent. He presented to our hospital with left back pain in March 2015. An abdominal radiograph and a noncontrast computed tomography showed extensive stone formation throughout the stent. A single cystolithotripsy and a double endoscopic combined intrarenal surgery (ECIRS)were performed. All the stones and the encrusted ureteral stent were successfully removed.

Risk factors of systemic inflammation response syndrome after endoscopic combined intrarenal surgery in the modified Valdivia position.

OBJECTIVE: To identify risk factors of developing systemic inflammation response syndrome after endoscopic combined intrarenal surgery in the modified Valdivia position for renal stone treatment. METHODS: We retrospectively analyzed 370 consecutive patients who underwent endoscopic combined intrarenal surgery procedures in the modified Valdivia position to treat renal stones. Antibiotic therapy based on preoperative urine cultures was administered to all patients from induction of anesthesia until at least postoperative day 3. Postoperative systemic inflammation response syndrome was diagnosed if the patient met two or more systemic inflammation response syndrome criteria. A multivariate logistic regression model with backward selection was used to evaluate the relationships between the incidence of systemic inflammation response syndrome after endoscopic combined intrarenal surgery and other clinical factors. RESULTS: Of the 370 patients, 61 patients (16.5%) were diagnosed with systemic inflammation response syndrome after endoscopic combined intrarenal surgery. Significant differences were found between the non-systemic inflammation response syndrome and systemic inflammation response syndrome groups with regard to female sex (29.8% vs 44.3%, P = 0.027), history of febrile urinary tract infection (16.5% vs 32.8%, P = 0.015) and number of involved calyces (2.68 vs 4.1, P < 0.001). Multivariate analysis found three independent predictors of postoperative systemic inflammation response syndrome: the number of involved calyces (P = 0.017), stone surface area (P = 0.021) and history of febrile urinary tract infection (P = 0.005). CONCLUSIONS: The number of involved calyces larger than four, stone surface area >500 mm(2) and a history of febrile urinary tract infection independently predicted the development of systemic inflammation response syndrome after endoscopic combined intrarenal surgery. This is the first study to identify the independent predictors of systemic inflammation response syndrome after endoscopic combined intrarenal surgery in the modified Valdivia position.