Comparison of endoscopic versus CT assessment of stone-free status after percutaneous nephrolithotomy (PCNL).

This study is aimed to determine whether postoperative low dose computed tomography (LDCT) imaging is necessary after percutaneous nephrolithotomy (PCNL), or the surgeon's intraoperative assessment of residual fragments (RF) is sufficient and avoidance of postoperative imaging with reduction of radiation exposure can be achieved. Data of all 610 patients who underwent PCNL in prone position in our institution from February 2009 to September 2020 was collected. Parameters such as age, gender, BMI, ASA-Classification, stone related parameters and the surgeon's assessment of stone-free status were analyzed. The LDCT performed postoperatively was compared to the intraoperative assessment of the surgeon regarding RF. The mean age of patients was 52.82 years; the mean BMI was 28.18 kg/m2. In 418 cases, the surgeon made a clear statement about the presence of RF and postoperative LDCT was carried out. The discrepancy between the two methods (surgeon´s assessment vs. LDCT) was significant at p < 0.0001. The sensitivity, specificity, positive and negative predictive value of the surgeon when assessing RF were 24.05%, 99.45%, 98.28% and 50%. Stone free rate (SFR) after primary PCNL was 45.57%. The overall SFR at discharge was 96.23%. Although the surgeon´s assessment of RF was reliable, postoperative LDCT imaging should still be performed if endoscopic stone clearance is suspected due to the high false negative rate and the low negative predictive value. The optimal timing of postoperative imaging following PCNL remains unclear.

Fully Automated Longitudinal Assessment of Renal Stone Burden on Serial CT Imaging Using Deep Learning.

Purpose: Use deep learning (DL) to automate the measurement and tracking of kidney stone burden over serial CT scans. Materials and Methods: This retrospective study included 259 scans from 113 symptomatic patients being treated for urolithiasis at a single medical center between 2006 and 2019. These patients underwent a standard low-dose noncontrast CT scan followed by ultra-low-dose CT scans limited to the level of the kidneys. A DL model was used to detect, segment, and measure the volume of all stones in both initial and follow-up scans. The stone burden was characterized by the total volume of all stones in a scan (SV). The absolute and relative change of SV, (SVA and SVR, respectively) over serial scans were computed. The automated assessments were compared with manual assessments using concordance correlation coefficient (CCC), and their agreement was visualized using Bland-Altman and scatter plots. Results: Two hundred twenty-eight out of 233 scans with stones were identified by the automated pipeline; per-scan sensitivity was 97.8% (95% confidence interval [CI]: 96.0-99.7). The per-scan positive predictive value was 96.6% (95% CI: 94.4-98.8). The median SV, SVA, and SVR were 476.5 mm3, -10 mm3, and 0.89, respectively. After removing outliers outside the 5th and 95th percentiles, the CCC measuring agreement on SV, SVA, and SVR were 0.995 (0.992-0.996), 0.980 (0.972-0.986), and 0.915 (0.881-0.939), respectively Conclusions: The automated DL-based measurements showed good agreement with the manual assessments of the stone burden and its interval change on serial CT scans.

[Assessment of radiopaque kidney stone treatment: Combination of extracorporeal shock wave lithotripsy and Fagolitos Plus®. Preliminary case control description.] / Evaluación del tratamiento de litiasis renal radiopaca mediante la combinación de litotricia extracorpórea por ondas de choque y Fagolitos Plus®. Estudio preliminar de casos y controles.

INTRODUCTION: The nutritional supplement called Fagolitos plus® contains hydroxycitric acid as main component, in addition to zinc, magnesium, vitamin A and vitamin B6. It is necessary to study new molecules as chemolytic treatment in calcium lithiasis or that facilitate its fragmentation with the help of other instrumental treatments. OBJECTIVE: The objective of this study is to evaluate the effectiveness of the combined treatment of Fagolitos plus® and extracorporeal lithotripsy in the fragmentation of the lithiasis. MATERIAL AND METHODS: Retrospective case-control study includes 88 patients with lithiasis. Group 1: Treated with 1 session of extracorporeal lithotripsy and Fagoliths plus®. Group 2: Treated with 1 session of extracorporeal lithotripsy. The variables analyzed were: Age, sex, body mass index, maximum diameter of the stone, area of the stone, hounsfield units of the stone measured by axial tomography, location of the stone, result after 1 session of extracorporeal wave lithotripsy shock [complete fragmentation, partial fragmentation (presence of a fragment greater than 5 mm) and absence of fragmentation (same size of the lithiasis)], adverse effects that occurred after taking Fagolitos plus®, days of treatment with Fagolitos plus® and energy shock wave applied to lithiasis. Results were analyzed with SPSS 20.0, p≤0.05. RESULTS: The mean age of the patients included in the study is 53.81 ± 12.62 years in group 1 compared to 56.53 ± 12.37 years in group 2, p=0.31. According to the distribution by sex, there were no statistically significant differences (p=0.5), including 24 men and 24 women in group 1 and 23 men and 17 women in group 2. The mean of body mass index of the patients in group 1 was 28.39 ± 2.27 kg/m2 in group 1 versus 28.39 ± 3.03 kg/m2 in group 2, p=0.9. The maximum diameter of the stone was 11.5 ± 3.91 mm in group 1 compared to 13.15 ± 5.49 mm in group 2, p=0.1. The area of the lithiasis measured by tomography was 104.74 ± 70.56 mm2 in group 1 compared to 141.91 ± 80.95 mm2 in group 2, p=0.3. The Hounsfield units measured by tomography of the lithiasis in group 1 was 1061.98 ± 213.68 compared to 1143.15 ± 172.24 in group 2, p=0.06. Relation to fragmentation, complete fragmentation was observed in 66.7% of group 1 patients, compared to 41% of group 2 patients (p=0.02), between 20-30 days after the first session of Extracorporeal Lithotripsy evaluated by means of a simple X-ray of the Abdomen. CONCLUSIONS: The administration of Fagolitos plus® concomitant to extracorporeal lithotripsy could increase its effectiveness in lithiasis fragmentation, requiring clinical trials and prospective studies to confirm these findings.

INTRODUCCIÓN: El complemento nutricional denominado Fagolitos plus® contiene como principal componente ácido hidroxicítrico, además de zinc, magnesio, vitamina A y vitamina B6. Es necesario estudiar nuevas moléculas como tratamiento quimiolítico en litiasis cálcica o que faciliten su fragmentación con la ayuda de otros tratamientos instrumentales. OBJETIVO: El objetivo de este estudio es evaluar la efectividad del tratamiento combinado de Fagolitos plus® y Litotricia extracorpórea en la fragmentación de la litiasis.MATERIAL Y MÉTODOS: Estudio retrospectivo de casos y controles, incluye 88 pacientes con litiasis. Grupo 1: Tratados con 1 sesión de litotricia extracorpórea y Fagolitos plus®. Grupo 2: Tratados con 1 sesión de litotricia extracorpórea. Las variables analizadas fueron: Edad, sexo, índice de masa corporal, diámetro máximo de la litiasis, área de la litiasis, unidades hounsfield de la litiasis medida por Tomografía axial, localización de la litiasis, resultado tras 1 sesión de Litotricia extracorpórea por ondas de choque [fragmentación completa, fragmentación parcial (presencia de un fragmento mayor a 5 mm) y ausencia de fragmentación (mismo tamaño de la litiasis)], efectos adversos acontecidos tras la toma de Fagolitos plus®, días de tratamiento con Fagolitos plus® y energía de ondas de choque aplicada a la litiasis. Se analizaron resultados con SPSS 20.0, p≤0,05. RESULTADOS: La edad media de los pacientes incluidos en el estudio es de 53,81 ± 12,62 años en el grupo 1 frente a 56,53 ± 12,37 años en el grupo 2, p=0,31. Según la distribución por sexos, tampoco existen diferencias estadísticamente significativas (p=0,5), incluyendo 24 hombres y 24 mujeres en el grupo 1 y 23 hombres y 17 mujeres en el grupo 2. El índice de masa corporal medio de los pacientes del grupo 1 fue de 28,39 ± 2,27 kg/m2 en el grupo 1 frente a 28,39 ± 3,03 kg/m2 en el grupo 2, p=0,9. El diámetro máximo de la litiasis fue de 11,5 ± 3,91 mm en el grupo 1 frente a 13,15 ± 5,49 mm en el grupo 2, p=0,1. El área de la litiasis medida por tomografía computarizada fue de 104,74 ± 70,56 mm2 en el grupo 1 frente a 141,91 ± 80,95 mm2 en el grupo 2, p=0,3. Las unidades Hounsfield medidas por tomografía de la litiasis en el grupo 1 fue de 1061,98 ± 213,68 frente a 1143,15 ± 172,24 en el grupo 2, p=0,06. En relación con la fragmentación, se observó fragmentación completa en el 66,7% de los pacientes del grupo 1, frente al 41% de los pacientes del grupo 2 (p=0,02) entre 20-30 días tras la primera sesión de Litotricia Extracorpórea evaluado mediante Radiografía simple de Abdomen. CONCLUSIONES: La administración de Fagolitos plus® concomitante a la Litotricia extracorpórea podría aumentar su efectividad en la fragmentación de la litiasis, siendo necesarios ensayos clínicos y estudios prospectivos que confirmen estos hallazgos.

Patients' poor performance status is an independent risk factor for urosepsis induced by kidney and ureteral stones.

This study was aimed to identify the risk factors for urosepsis caused by kidney and ureteral stones. One hundred and nine patients who had kidney or ureteral stones and who were treated with trans-ureteral lithotripsy (TUL) at our institution from 2016 to 2020 were included. We investigated the risk factors for urosepsis caused by kidney or ureteral stones that occurred prior to TUL. Thirty patients (28%) had urosepsis prior to TUL. Patients were divided into a urosepsis group (n = 30, 28%) and a non-urosepsis group (n = 79, 72%). Patients' characteristics (gender, age, performance status [PS] score, presence of diabetes mellitus, and skeletal muscle mass), as well as their stone and urine characteristics (stone size, presence of obstructive ureteral stones, stone composition, and urine and stone cultures), were compared between the two groups. When compared to the non-urosepsis group, patients with urosepsis were more likely to be older (p < 0.001), female (p < 0.001), with lower skeletal muscle mass (p < 0.001) and with poor PSs (p < 0.001). For stone and urine characteristics, infection stones (p = 0.01), positive urine (p < 0.001) and stone culture (p = 0.007) were more often detected in patients with urosepsis. A multivariate analysis showed patients' poor PS to be an independent risk factor for urosepsis due to kidney and ureteral stones (OR = 15.7; 95% CI = 2.2-115, p = 0.007). Our study revealed that the most significant risk factor for urosepsis caused by kidney and ureteral stones was the patients' poor PS.

Assessment of the Contrast-Enhanced Ultrasound in Percutaneous Nephrolithotomy for the Treatment of Patients with Nondilated Collecting System.

Purpose: To investigate the clinical value of contrast-enhanced ultrasound (CEUS) in percutaneous nephrolithotomy (PCNL) for kidney stone patients without hydronephrosis. Methods: Patients with nondilated collecting system kidney stones who underwent PCNL between October 2018 and December 2019 at our hospital were enrolled in this study. Patients who met the inclusion criteria were randomized into two groups: a CEUS-guided PCNL group and a conventional ultrasound (US)-guided PCNL group. The operation results of the two groups were compared, including the number of attempts for effective puncture, duration to effective puncture, stone clearance rate, blood loss, postoperative complications, and hospital stay. Results: Fifty-six patients with a nondilated collecting system who underwent PCNL for 60 kidneys were included in this study, including 4 patients who underwent bilateral PCNL due to bilateral renal stones. There were 30 kidneys in each group. All patients successfully underwent PCNL. The CEUS-guided PCNL group had more accurate punctures, with a higher effective rate of one puncture and shorter puncture time. There was no statistically significant difference in stone clearance rate between the two groups. Four cases of double channels were established in the conventional US-guided PCNL group, while there was only one case in the CEUS-guided PCNL group. In the CEUS-guided PCNL group, most cases (96.7%, 29/30) had no or only mild complications, which were significantly better than the conventional US-guided PCNL group (76.7%, 23/30). The mean postoperative hemoglobin loss in the CEUS-guided PCNL group was 9.5 (range 1-25) g/L, which was significantly lower than 15.5 (range 5-52) g/L in the conventional US-guided PCNL group. Conclusion: The CEUS technique can improve visibility of the nondilated renal collecting system, facilitate selection of suitable calix, and identify renal calix fornix. It also benefits needle placement in patients with a nondilated collecting system.

A prospective, matched comparison of ultra-low and standard-dose computed tomography for assessment of renal colic.

OBJECTIVE: To determine the diagnostic accuracy of ultra-low-dose computed tomography (ULDCT) compared with standard-dose CT (SDCT) in the evaluation of patients with clinically suspected renal colic, in addition to secondary features (hydroureteronephrosis, perinephric stranding) and additional pathological entities (renal masses). PATIENTS AND METHODS: A prospective, comparative cohort study was conducted amongst patients presenting to the emergency department with signs and symptoms suggestive of renal or ureteric colic. Patients underwent both SDCT and ULDCT. Single-blinded review of the image sets was performed independently by three board-certified radiologists. RESULTS: Among 21 patients, the effective radiation dose was lower for ULDCT [mean (SD) 1.02 (0.16) mSv] than SDCT [mean (SD) 4.97 (2.02) mSv]. Renal and/or ureteric calculi were detected in 57.1% (12/21) of patients. There were no significant differences in calculus detection and size estimation between ULDCT and SDCT. A higher concordance was observed for ureteric calculi (75%) than renal calculi (38%), mostly due to greater detection of calculi of <3 mm by SDCT. Clinically significant calculi (≥3 mm) were detected by ULDCT with high specificity (97.6%) and sensitivity (100%) compared to overall detection (specificity 91.2%, sensitivity 58.8%). ULDCT and SDCT were highly concordant for detection of secondary features, while ULDCT detected less renal cysts of <2 cm. Inter-observer agreement for the ureteric calculi detection was 93.9% for SDCT and 87.8% for ULDCT. CONCLUSION: ULDCT performed similarly to SDCT for calculus detection and size estimation with reduced radiation exposure. Based on this and other studies, ULDCT should be considered as the first-line modality for evaluation of renal colic in routine practice.

Stone-Free Rate after Treating Kidney Stones Exceeding 10 mm via Flexible Ureteroscopy: Can Endoscopic Assessment Replace Low-Dose Computed Tomography Control?

INTRODUCTION: It is unclear whether endoscopic assessment of the stone-free rate after flexible ureteroscopy (fURS) is as effective as assessment with low-dose computed tomography (CT) scan. METHODS: Prospective documentation of patients with kidney stones > 10 mm diameter from 2 different centers (Freiburg, Regensburg), who underwent fURS and were declared to be endoscopically completely stone-free. Low-dose CT control performed 4-8 weeks postoperatively. RESULTS/CONCLUSION: Thirty-eight patients were treated between October 2015 and August 2016 (12 F, 26 M). Average age was 55.9 years (range 19-82, SD 17.24), and body mass index was 29.7 kg/m2 (range 23.5-42.5, SD 4.37). There were 2.0 (range 1-7, SD 1.55) stones with a mean diameter of 15 mm (range 10-40, SD 6.78) per kidney. Mean surgery time was 74 min (range 38-124, SD 24.28), and lithotripsy was necessary in 33 cases. CT was performed 5.4 weeks afterwards (range 4-8, SD 1.43). One patient had a 2 mm residual which was extracted by URS. Strictly speaking, endoluminal stone removal control failed in only that patient, yielding a negative predictive value of 97%. A routine postoperative CT scan would thus appear unnecessary in the case of negative endoscopic control for residual fragments and should be avoided to reduce radiation exposure. Further investigations with larger patient populations are necessary.

Increasing Use, Geographic Variation, and Disparities in Emergency Department CT for Suspected Urolithiasis.

PURPOSE: The aim of this study was to examine changing characteristics of utilization and potential disparities in US emergency department (ED) patients undergoing CT of the abdomen and pelvis (CTAP) for suspected urolithiasis. METHODS: A retrospective study was conducted among all patients from 2006 to 2015 with a primary diagnosis of suspected urolithiasis within the Nationwide Emergency Department Sample, the largest publicly available all-payer ED database in the United States. The annual numbers of ED visits for suspected urolithiasis and associated CTAP examinations per visit were determined. The compound annual growth rate for CTAP was calculated. Using multivariate logistic regression analyses, patient demographics and payer and hospital characteristics were evaluated as potential independent predictors of utilization. RESULTS: Nationwide, the number of ED visits per year for suspected urolithiasis increased from 1,057,119 in 2006 to 1,246,041 in 2014 (relative +17.9%), whereas the annual use of CTAP increased from 24.6% to 49.4% per visit (relative +100.8%; CAGR +8.0%). Multivariate analysis showed higher CTAP use associated with higher patient household income ZIP code quartile (odds ratio [OR] for wealthiest/poorest, 1.48), private payer (ORs, 1.21 versus Medicare and 1.22 versus Medicaid), Northeast geographic region (ORs, 5.07 versus Midwest, 4.16 versus West, and 1.77 versus South), hospital urban status (OR, 1.42), and nonteaching hospitals (OR, 1.20) (P < .05 for all). CONCLUSIONS: The relative use of CTAP in ED patients presenting with suspected urolithiasis doubled between 2006 and 2014 and showed marked geographic variation. Among ED patients with suspected urolithiasis, CTAP was more frequent in patients from higher household income ZIP codes, with private insurance, in the Northeast, and at urban and nonteaching hospitals.

[Modern radiology diagnostics methods for assessment of renal perfusion in patients with urinary stone disease].

Urinary stone disease is the current issue for healthcare system worldwide. High prevalence of urinary stone disease (at least 5% of the population of developed countries) determines clinical significance of the studying of its etiology and pathogenesis, improving of diagnostic methods and novel treatment technologies. The development of endoscopic devices, creation of new eswl machines and improvement of endourology interventions under X-ray guidance allowed to solve the problem of surgical treatment. Therefore, one of the actual issue is the choice of X-ray method for predicting and evaluating of treatment efficiency in patients with urinary stone disease. The changes of renal blood flow depend on urodynamic disturbances, stone location and size, the duration of disease, complications, patients age. Therefore, for comprehensive studying of renal function the hemodynamics evaluation is needed. In this review the advantages, drawbacks and perspective on developing of different radiologic methods for renal hemodynamic assessment are given.

Assessment of Residual Stone Fragments After Retrograde Intrarenal Surgery.

OBJECTIVES: To define the most suitable approach to assess residual stone fragments after retrograde intrarenal surgery (RIRS). METHODS: Ninety-two patients (115 renal units) submitted to RIRS for symptomatic kidney stones >5 mm and <20 mm or <15 mm in the lower Calyx diagnosed by noncontrast CT (NCCT) were prospectively studied. Residual fragments were assessed by endoscopic evaluation (END) at the end of the procedure and by NCCT, ultrasonography (US), and kidney, ureter, and bladder radiograph (KUB) on the 90th postoperative day (POD). NCCT was considered the gold standard for the evaluation of residual fragments after RIRS. RESULTS: The 90th POD NCCT resulted in stone-free status in 74.8% (86/115), 0-2 mm in 8.7% (10/115), and >2 mm residual fragments in 16.5% (19/115) renal units. Stone-free status by END at the end of RIRS was coincident with NCCT in 93.0% of the cases (40/43). There were no cases of residual fragments >2 mm on NCCT if END resulted in stone-free status. In all cases where END resulted in residual fragments >2 mm, US proved to be correct according to NCCT. Neither US nor KUB was able to identify residual fragments between 0 and 2 mm. KUB had only 31.6% (6/19) sensitivity to detect residual fragments >2 mm and did not add sensitivity or specificity to US. CONCLUSIONS: In the follow-up imaging after RIRS, we suggest that if END resulted in residual fragments <2 mm, a 90th POD NCCT should be performed. US may be used if END showed fragments >2 mm.

Dusting Efficiency of the Moses Holmium Laser: An Automated In Vitro Assessment.

INTRODUCTION: Moses technology is a novel Holmium:YAG laser system designed to minimize stone retropulsion and improve stone ablation when the laser is not in direct contact with the stone. Our aim was to assess the efficiency of Moses technology relative to short- and long-pulse lithotripsy using an automated in vitro "dusting model" of stone comminution. METHODS: All tests were conducted using a Lumenis Pulse 120H Holmium:YAG laser with a 365 µm Moses D/F/L fiber. "Hard" (15:3) and "soft" (15:6) Begostones mimicking calcium oxalate monohydrate and uric acid stones, respectively, were used. To assess ablation efficiency and fiber tip degradation, a dusting model was employed: the laser was moved by a three-dimensional positioning system in a spiral motion across a flat Begostone surface submerged in water. Ablation efficiency was measured as stone mass loss after 4 kJ of energy delivery. Fiber tip degradation was measured at 1 kJ intervals. Comparative trials with short pulse, long pulse, Moses contact, and Moses distance settings were completed with the laser tip positioned at 0, 1, and 2 mm distances from the stone at energy settings of 0.4 J delivered at 70 Hz. RESULTS: In our dusting model, stone ablation was significantly greater the closer the laser was to the stone. On hard stones, pulse type did not have a significant impact on ablation at any distance. On soft stones at 0 mm, Moses contact produced the greatest ablation, significantly greater than long pulse (p < 0.05). At 1 mm, Moses distance produced significantly greater ablation than all other settings (p = 0.025) and was as effective as long or short pulse at 0 mm. At 2 mm distance, no pulse type demonstrated significantly different ablation. Fiber tip degradation was minimal and not significant between settings. CONCLUSIONS: Moses technology delivers greater ablation of soft stones when in contact and 1mm from the stone surface.

Steep Infundibulopelvic Angle as a New Risk Factor for Flexible Ureteroscope Damage and Complicated Postoperative Course.

OBJECTIVE: The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing repair costs represent a substantial burden for urological departments worldwide. No risk factors of flexible ureteroscope damage have been identified so far. The objective of this study was to investigate the impact of infundibulopelvic angle (IPA) on device damage and on other intraoperative and postoperative factors such as length of hospital stay, surgical complications, stone-free rate (SFR), operation, and fluoroscopy time. MATERIALS AND METHODS: In a retrospective monocentric study, IPA was measured based on intraoperative retrograde pyelography images taken during fURS. All procedures were conducted with modern reusable flexible ureteroscopes: Karl Storz Flex-X2 or Olympus URF-V. Statistical analysis was performed in RStudio (version 1.0.136) with the unpaired t-test and Mann-Whitney U test. Pearson correlation coefficient (Pearson's r) was measured whenever applicable. RESULTS: In total, 381 fURS performed between September 2013 and March 2017 were analyzed: 260 (68.24%) for kidney stone operation and 121 (31.76%) for diagnostic purposes; of these, 38 (9.97%) devices were postoperatively deemed defective. IPA values were significantly steeper in cases with flexible ureteroscope damage compared to cases without damage (median 42.5 degrees vs 56.0, p < 0.001). Steeper IPA was significantly associated with the occurrence of Clavien-Dindo ≥2 complications (median 51.0 degrees vs 55.0, p = 0.005) as well as prolonged hospital stay (median 51.0 degrees vs 55.0, p = 0.014). No influence on SFR was observed (p > 0.05). IPA did not correlate with operation or fluoroscopy time. CONCLUSIONS: Steep IPA can be considered the first risk factor predicting both flexible ureteroscope damage and an unfavorable postoperative course. A better understanding of damage mechanisms is the key for the proper indications to use costly single-use devices.

Predictability and Practicality of Image-Based Scoring Systems for Patient Assessment and Outcome Stratification During Percutaneous Nephrolithotomy: a Contemporary Update.

Preoperative nomograms offer systematic and quantitative methods to assess patient- and stone-related characteristics and their impact on successful treatment and potential risk of complication. Discrepancies in the correlation of perioperative variables to patient outcomes have led to the individual development, validation, and application of four independent scoring systems for the percutaneous nephrolithotomy: Guy's stone score, S.T.O.N.E. nephrolithometry, Clinical Research Office of the Endourology Society nomogram, and Seoul National University Renal Stone Complexity. The optimal nomogram should have high predictive ability, be practically integrated into clinical use, and be widely applicable to urinary stone disease. Herein, we seek to provide a contemporary evaluation of the advantages, disadvantages, and commonalities of each scoring system. While the current data is insufficient to conclude which scoring system is destined to become the gold standard, it is crucial that a nephrolithometric scoring system be incorporated into common practice to improve surgical planning, patient counseling, and outcome assessment.

Use of medical expulsive therapy in children: An assessment of nationwide practice patterns and outcomes.

INTRODUCTION: Early data support the use of medical expulsive therapy (MET) in children. However, little is known regarding use or outcomes associated with MET outside of pediatric-specific practices. Using a national administrative dataset, we sought to characterize utilization patterns of MET as well as assess outcomes associated with MET exposure. STUDY DESIGN: We interrogated the MarketScan Commercial Claims and Encounters database to identify children under the age of 18 presenting to the emergency department (ED) with any diagnosis of upper urinary tract calculi (UUTC, including renal and ureteral calculi). MET exposure was defined as having a prescription filled for a MET agent within 1 week of the ED encounter. Characteristics of children receiving MET were defined and outcomes compared between children with and without MET exposure. RESULTS: Of 1325 children included in the study, 13.2% received MET, including 15.4% of children with a diagnosis of "calculus of the ureter." MET use increased significantly throughout the study period (p = 0.004), although only 30.4% of children considered potential MET candidates received MET in the final year of the study (2013). Among all patients, receipt of MET was associated with male gender, presence of comorbidity, provider-type (urologist), and year of diagnosis, although among those with a specific diagnosis of "calculus of the ureter," only year of diagnosis remained a significant factor. Rates of unplanned physician visits and surgical interventions were similar between groups. Children receiving MET were more likely to receive follow-up imaging, although only 46% of children with ureteral calculi had appropriate follow-up imaging within 90 days, regardless of MET exposure. Odds ratios of factors and outcomes associated with MET exposure are shown in the Table. DISCUSSION: Although early data support safety and efficacy MET in children, nationwide use in children is low among potential candidates for MET. For children with ureteral calculi, only year of diagnosis was a significant factor associated with MET use. No difference in unplanned physician visits or surgical interventions was noted. Most notable, however, was the low rate of follow-up imaging within 90 days for children presenting acutely with UUTC. CONCLUSIONS: Use of MET for children with ureteral calculi is increasing, although still fewer than a third of children considered potential candidates receive this treatment. Follow-up imaging is not obtained for many children with ureteral calculi. Future work is needed to standardize management and follow-up protocols for children with acute renal colic.

Trends in Imaging Use for the Evaluation and Followup of Kidney Stone Disease: A Single Center Experience.

PURPOSE: Recent reports support renal ultrasound as the initial imaging study to evaluate patients with suspected renal colic. However, urologists often advocate for computerized tomography to better define stone size and location, especially before proceeding with endourological intervention. One concern with using ultrasound as initial imaging is that computerized tomography may be required later, obviating the reduction in costs and radiation gained by using ultrasound. MATERIALS AND METHODS: We retrospectively reviewed the electronic health records of 10,680 episodes of stone disease in a total of 7,659 patients who presented to the emergency department or walk-in clinic with a chief complaint or visit diagnosis of urolithiasis from 2009 to 2015 at a single institution. Images obtained during the index encounter and in the following 90 days were recorded. RESULTS: The index encounter included computerized tomography in 47% of episodes, ultrasound in 20%, plain x-ray of the kidneys, ureters and bladder in 12% and no imaging in 29%. Of the index visits 49% included multiple testing. If no computerized tomography was obtained during the index visit, 10% of patients underwent computerized tomography later in the episode. Total imaging costs and radiation exposure during 90 days were significantly higher when computerized tomography was done at the index visit. If the initial image obtained during an episode was ultrasound, computerized tomography was performed in 20% of cases within 90 days. CONCLUSIONS: Of patients who underwent an initial ultrasound 80% avoided computerized tomography imaging. Avoiding computerized tomography at the index visit was associated with substantial reductions in radiation exposure and imaging costs.

Assessment of the SonixGPS system for its application in real-time ultrasonography navigation-guided percutaneous nephrolithotomy for the treatment of complex kidney stones.

SonixGPS is a novel real-time ultrasonography navigation technology, which has been demonstrated to promote accuracy of puncture in surgical operations. The aim of this study is to evaluate its application in guiding the puncture during percutaneous nephrolithotomy (PCNL). We retrospectively reviewed our experience in treating a total of 74 patients with complex kidney stones with PCNL, in which puncture in 37 cases were guided by SonixGPS system, while the other 37 by conventional ultrasound. The effectiveness of operation was evaluated in terms of stone clearance rate, operation time, time to successful puncture, number of attempts for successful puncture and hospital stay. The safety of operation was examined by evaluating postoperative complications. Our retrospective review showed that although there were no significant differences in stone clearance rates between the groups, SonixGPS guidance resulted in more puncture accuracy with shorter puncture time and higher successful puncture rate. Under the help of SonixGPS, most patients (92 %) had no or just mild complications, compared to that (73 %) in conventional ultrasound group. Post-operative decrease of hemoglobin in SonixGPS group was 13.79 (7-33) mg/dl, significantly lower than that 20.97 (8-41) mg/dl in conventional ultrasound group. Our experience demonstrates that SonixGPS is superior to conventional ultrasound in guiding the puncture in PCNL for the treatment of complex kidney stone.

Residual stones after percutaneous nephrolithotomy: comparison of intraoperative assessment and postoperative non-contrast computerized tomography.

OBJECTIVES: To compare the intraoperative surgeon perspective for detection of residual fragments (RFs) after percutaneous nephrolithotomy (PNL) with postoperative NCCT. METHODS: A prospective study of adult patients who underwent PNL between March and September 2014 was conducted. Stone complexity was evaluated using the Guy's stone score (GSS). All patients were evaluated by pre- and postoperative NCCT. After the procedure, the surgeon had been asked whether there were residual stones or not. The sensitivity, specificity and predictive values were tested against postoperative NCCT. Predictors of accurate intraoperative assessment were determined using univariate and multivariate statistical analyses. RESULTS: The study included 306 consecutive patients. The surgeons reported no residual stones in 236 procedures; of whom 170 (72%) were reported stone-free by NCCT. On the other hand, 65 out of 70 procedures (93%) reported with residual stones by the surgeons were true by NCCT. The sensitivity was 50% and the NPV was 72%, while the specificity was 97% and the PPV was 93%. On multivariate analysis, only lower GSS (p < 0.001) was independently associated with true negative surgeon opinion. CONCLUSIONS: Although there was a high surgeon ability to detect post-PNL residual stones, postoperative imaging is mandatory because of the high false negative rates and low NPV. The surgeon opinions can be judged only in stones with lower GSS. The NPV could be enhanced if a consistent definition of clinically significant RFs is introduced.

Understanding the costs of flexible ureteroscopy.

Ureteroscopy (URS) is the first line treatment for the majority of symptomatic renal and ureteral stones. This review summarizes the current literature on the costs associated with URS. A high initial investment is required for scope acquisition. Once purchased, maintenance and repair costs continue to accrue. Durability of the scopes is an important consideration as more durable scopes will remain functional for longer and thus have lower overall repair costs. Currently available, newer generation scopes appear highly durable compared to their predecessors. Ancillary equipment, mostly disposable items represent the highest per procedure cost of URS. Despite these costs, URS remains highly profitable. However, it is also efficacious demonstrating superior cost-effectiveness with higher stone free rates at a lower cost relative to shock wave lithotripsy.