Emergency department visits, use of imaging, and drugs for urolithiasis have increased in the United States. Kidney Int. 2013;83:479-486. [PMID: 23283137 PMCID: PMC3587650 DOI: 10.1038/ki.2012.419]

Trends in Opioid and Nonsteroidal Anti-Inflammatory Drug Use for Patients with Kidney Stones in United States Emergency Departments from 2015 to 2021

Introduction: Renal colic is frequently treated with opioids; however, narcotic analgesic use can lead to dependence and abuse. We evaluated use trends of opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) for pain management of kidney stones in United States emergency departments (EDs) from 2015 to 2021. Methods: Kidney stone encounters were identified using National Hospital Ambulatory Medical Care Survey data. We applied a multistage survey weighting procedure to account for selection probability, nonresponse, and population weights. Medication use trends were estimated through logistic regressions on the timing of the encounter, adjusted for selected demographic and clinical characteristics. Results: Between 2015 and 2021, there were an estimated 9,433,291 kidney stone encounters in United States EDs. Opioid use decreased significantly (annual odds ratio [OR]: 0.87, p = 0.003), and there was no significant trend in NSAID use. At discharge, male patients were more likely than females (OR: 1.93, p = 0.001) to receive opioids, and Black patients were less likely than White patients (OR: 0.34, p = 0.010) to receive opioids. Regional variation was also observed, with higher odds of discharge prescriptions in the West (OR: 3.15, p = 0.003) and Midwest (OR: 2.49, p = 0.010), compared with the Northeast. Thirty-five percent of patients received opioids that were stronger than morphine. Conclusion: These results suggest improved opioid stewardship from ED physicians in response to the national opioid epidemic. However, regional variation as well as disparities in discharge prescriptions for Black and female patients underscore opportunities for continued efforts.

Point-of-care ultrasound associated with shorter length of stay than computed tomography for renal colic

BACKGROUND

Despite similar diagnostic effectiveness for renal colic, computed tomography (CT) is more resource intensive than point-of-care ultrasound (PoCUS). We sought to compare Emergency Department (ED) length of stay (LOS) among patients with renal colic according to imaging modality utilized. We secondarily compared rates of infection, return ED visits, missed significant pathology, and urologic intervention.

METHODS

This was a 12-month (1/1/22-12/31/22) multi-site retrospective cohort study of all patients diagnosed with renal colic who presented to the ED on days when at least one patient had a billable renal PoCUS examination performed. Patients with a history of genitourinary malignancy, pregnancy, renal transplant, hemodialysis, single kidney, prior visit for renal colic in the previous 30 days, or an incomplete workup were excluded. Median ED LOS was compared using a Wilcoxon rank sum test, and the 95% confidence limits for the difference between medians was calculated. Secondary outcomes were compared using a Fisher's Exact test.

RESULTS

Of 415 patients screened, 325 were included for analysis: 150 had CT alone, 80 had PoCUS alone, 54 had PoCUS plus CT, and 41 had neither. Median LOS for PoCUS alone was 75.0 (95% CI 39.3-110.7) minutes shorter than CT alone (231.5 vs. 307.0 min, p < 0.0001). Similar rates of infection, return visits, and missed pathology occurred across all groups (p > 0.10). Urologic interventions were higher in the PoCUS plus CT (25.9%) group compared to CT alone (7.3%), PoCUS alone (2.5%), and neither (7.3%), p < 0.0001.

CONCLUSION

Among patients with renal colic, PoCUS was associated with shorter ED LOS compared to CT, without differences in infection rates, return visits, or missed pathology. Patients with PoCUS plus CT had a higher rate of urologic interventions, suggesting PoCUS may have a role in identifying patients who would most benefit from CT.

Predictors for emergency readmission in patients with ureteral calculi: a focus on pain management and stone location

BACKGROUND

The management of patients with ureteral calculi in the emergency department (ED) remains challenging due to high revisit rates.

PURPOSE

To identify predictors of revisits among patients with ureteral calculi in the ED.

DESIGN, SETTING, AND PARTICIPANTS

Data from patients who presented at a tertiary academic hospital in Seoul, Republic of Korea, between February 2018 and December 2019, were analyzed retrospectively.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Variables, including the respiratory rate (RR), estimated glomerular filtration rate (eGFR), duration of pain, number of analgesic doses, location of ureteral calculi, and ED length of stay (LOS) were examined using logistic regression. We also examined some additional variables included in the STONE and CHOKAI scoring systems to examine their association with revisit.

RESULTS

Significant predictors of revisits included the number of analgesic doses and the location of ureteral calculi. Patients who required multiple analgesic doses or those with proximal or mid-ureteral calculi were more likely to revisit the ED. Although the STONE and CHOKAI scores could predict uncomplicated ureteral calculi, we found that the CHOKAI score is a valuable tool for predicting the likelihood of patient revisits (p = 0.021).

CONCLUSIONS

Effective pain management and consideration of calculi location are important for predicting patient revisits. More research is required to validate findings, develop precise predictive models, and empower tailored care for high-risk patients. In patients with ureteral calculi in the ED, the number of analgesics given and stone location predict return visits. Proximal ureteral calculi on CT may require early urologic intervention to prevent pain-related revisits.

Leveraging behavioral modification technology for the prevention of kidney stones

PURPOSE OF REVIEW

The purpose of this review is to examine the use of technology to help promote and maintain behaviors that decrease stone recurrence.

RECENT FINDINGS

Behavior change is a complex process with various interacting components. Recent developments have sought to utilize technology in combination with behavioral change techniques to promote behavior that lowers stone recurrence risk. Smart water bottles are becoming a popular way to accurately measure fluid intake with variable impact on adherence to the recommended daily fluid intake. Mobile apps have also been explored as a method to improve fluid intake. Interventions that combine smart water bottles, mobile apps, and behavioral change techniques have shown the most promise in promoting increased daily fluid intake. Other technologies, such as smart pill dispensers and hydration monitors, have potential applications in promoting behavioral change for stone disease but have yet to be evaluated for this purpose.

SUMMARY

There is a limited number of studies exploring technology as a means to promote and maintain behaviors that decrease urinary stone recurrence. Future research is needed to elucidate how to maximize the potential of these technologies and better understand which behavioral change techniques best promote habit formation for the prevention of stones.

Improved Detection of Urolithiasis Using High-Resolution Computed Tomography Images by a Vision Transformer Model

PURPOSE

Urinary stones cause lateral abdominal pain and are a prevalent condition among younger age groups. The diagnosis typically involves assessing symptoms, conducting physical examinations, performing urine tests, and utilizing radiological imaging. Artificial intelligence models have demonstrated remarkable capabilities in detecting stones. However, due to insufficient datasets, the performance of these models has not reached a level suitable for practical application. Consequently, this study introduces a vision transformer (ViT)-based pipeline for detecting urinary stones, using computed tomography images with augmentation.

METHODS

The super-resolution convolutional neural network (SRCNN) model was employed to enhance the resolution of a given dataset, followed by data augmentation using CycleGAN. Subsequently, the ViT model facilitated the detection and classification of urinary tract stones. The model's performance was evaluated using accuracy, precision, and recall as metrics.

RESULTS

The deep learning model based on ViT showed superior performance compared to other existing models. Furthermore, the performance increased with the size of the backbone model.

CONCLUSION

The study proposes a way to utilize medical data to improve the diagnosis of urinary tract stones. SRCNN was used for data preprocessing to enhance resolution, while CycleGAN was utilized for data augmentation. The ViT model was utilized for stone detection, and its performance was validated through metrics such as accuracy, sensitivity, specificity, and the F1 score. It is anticipated that this research will aid in the early diagnosis and treatment of urinary tract stones, thereby improving the efficiency of medical personnel.

Effect of gender on presentation and outcome of renal colic

OBJECTIVES

To examine gender-related differences in the presentation, management, and outcomes of patients admitted to the emergency department ED with ureteral stones.

METHODS

Retrospective analysis of all patients admitted to the ED at our institution, found to have a ureteral stone on CT. Clinical, laboratory, imaging parameters, and outcomes were collected.

RESULTS

778 patients were admitted with ureteral stones between January 2018 and December 2020. 78% (n = 609) were males and 22% (n = 169) were females. The mean ages were 49.4 (SD 14.4) and 51.6 (SD 15.7) in males and females, respectively (p = 0.08). Female patients presented with a higher body temperature (p = 0.01), pulse rate (p < 0.0001), nausea and vomiting (p < 0.0001), elevated serum C-reactive protein (CRP) (p = 0.002) compared to males. The prevalence of elevated serum creatinine was higher in males (p < 0.0001). Alpha-blockers were recommended on discharge in 54.8% (334) of males, compared to only 29.6% (50) of females (p < 0.0001). Spontaneous stone expulsion was significantly higher in males compared to females (p = 0.01).

CONCLUSIONS

Our results demonstrate that gender does effect presentation and outcome of patients presenting with renal colic. Females were found to have elevated infectious parameters, more nausea and vomiting and a higher incidence of positive urine cultures. Males admitted to the ED were found to have significantly higher serum creatinine levels. Medical expulsive therapy (MET) with alpha-blockers was prescribed significantly less in female patients, which may have resulted in a lower spontaneous stone expulsion rate.

Machine Learning Models to Predict Kidney Stone Recurrence Using 24 Hour Urine Testing and Electronic Health Record-Derived Features

Objective

To assess the accuracy of machine learning models in predicting kidney stone recurrence using variables extracted from the electronic health record (EHR).

Methods

We trained three separate machine learning (ML) models (least absolute shrinkage and selection operator regression [LASSO], random forest [RF], and gradient boosted decision tree [XGBoost] to predict 2-year and 5-year symptomatic kidney stone recurrence from electronic health-record (EHR) derived features and 24H urine data (n = 1231). ML models were compared to logistic regression [LR]. A manual, retrospective review was performed to evaluate for a symptomatic stone event, defined as pain, acute kidney injury or recurrent infections attributed to a kidney stone identified in the clinic or the emergency department, or for any stone requiring surgical treatment. We evaluated performance using area under the receiver operating curve (AUC-ROC) and identified important features for each model.

Results

The 2- and 5- year symptomatic stone recurrence rates were 25% and 31%, respectively. The LASSO model performed best for symptomatic stone recurrence prediction (2-yr AUC: 0.62, 5-yr AUC: 0.63). Other models demonstrated modest overall performance at 2- and 5-years: LR (0.585, 0.618), RF (0.570, 0.608), and XGBoost (0.580, 0.621). Patient age was the only feature in the top 5 features of every model. Additionally, the LASSO model prioritized BMI and history of gout for prediction.

Conclusions

Throughout our cohorts, ML models demonstrated comparable results to that of LR, with the LASSO model outperforming all other models. Further model testing should evaluate the utility of 24H urine features in model structure.

Value of detected hydronephrosis and hydroureter on ultrasound for detecting a ureteral stone: a retrospective study

To investigate the predictive value of hydronephrosis and hydroureter in the detection of ureteral stones using ultrasound, a total of 366 patients suffering from ureteral stones confirmed by ultrasound, computed tomography (CT) and their follow-up treatments were consecutively collected. All the included patients underwent systematic ultrasound scanning of the kidney and ureter. The hydronephrosis and hydroureter in each patient were measured using a digital caliper. Then, receiver operating characteristic (ROC) curve analysis was used to determine the optimal cutoff values for hydronephrosis and hydroureter to predict a ureteral stone's location and size. The hydronephrosis, hydroureter, and stone size measurements showed good interobserver agreement (P < 0.001). Using the lower border of the sacroiliac joint as a demarcation point, we found larger widths of hydronephrosis and hydroureter in the proximal ureteral stone group than in the distal ureteral stone group (P < 0.001). Additionally, 10.9 mm and 5.9 mm were identified as optimal cutoff values for predicting a distal position (P < 0.001), with no significant difference in their predictive value (P > 0.05). Similar comparisons between groups based on size stratification revealed no significant difference in hydronephrosis between the > 5 mm group and the ≤ 5 mm group. However, the hydroureter was larger in the > 5 mm group than in the ≤ 5 mm group after identifying 6 mm as the best cutoff (P =0.004). In summary, the ultrasound measurement of hydronephrosis and hydroureter may predict the position and size of a possible ureteral stone in patients with colic symptoms.

Recent trends in the prescription of opioids in the emergency department in patients with urolithiasis

PURPOSE

Pain management is central in the treatment of urolithiasis. We aimed to estimate the impact of the 2017 Department of Health and Human Services declaration of an opioid crisis on prescribing patterns of opioids and NSAIDs in emergency department visits for urolithiasis.

METHODS

The National Health Ambulatory Medical Care Survey (NHAMCS) was queried for emergency department visits of adults with a diagnosis of urolithiasis. The association between urolithiasis and narcotic and NSAIDs prescription patterns was evaluated and compared at pre-declaration (2014-2016) to post-declaration (2017-2018) periods.

RESULTS

Opioids were prescribed in about 211 million (41.1%) out of 513 million emergency department visits, over a 5-year period. Diagnosis of urolithiasis accounted for 1.9% of the visits (6.0 million). The use of opioids was higher in urolithiasis (82.7%) compared to non-urolithiasis diagnosis (40.3%), as well as the use of multiple opioids per visit (p < 0.01 for all). There was an overall decrease in opioid prescriptions in the post-declaration period, - 4.3% for urolithiasis (p = 0.254) and - 5.6% for non-urolithiasis visits (p < 0.05). A decrease in the use of hydromorphone (- 47.5%. p < 0.001), an increase in the use of morphine (+ 59.7% p = 0.006), and an increase of 'other' opioids (+ 98.8%, p < 0.041), were observed. Opioids combined with NSAIDs comprised 72.6% of the opioid prescriptions and 62.3% of all analgesic prescriptions in visits with urolithiasis diagnosis.

CONCLUSIONS

The use of opioids when managing urolithiasis decreased 4.3% after the crisis declaration; however, statistically are not different from pre-declaration numbers. Most often, opioids were prescribed with NSAIDs in urolithiasis patients.

Detecting Hydronephrosis Through Ultrasound Images Using State-of-the-Art Deep Learning Models

The goal of this study was to assess the feasibility of three models for detecting hydronephrosis through ultrasound images using state-of-the-art deep learning algorithms. The diagnosis of hydronephrosis is challenging because of varying and non-specific presentations. With the characteristics of ready accessibility, no radiation exposure and repeated assessments, point-of-care ultrasound becomes a complementary diagnostic tool for hydronephrosis; however, inter-observer variability still exists after time-consuming training. Artificial intelligence has the potential to overcome the human limitations. A total of 3462 ultrasound frames for 97 patients with hydronephrosis confirmed by the expert nephrologists were included. One thousand six hundred twenty-eight ultrasound frames were also extracted from the 265 controls who had normal renal ultrasonography. We built three deep learning models based on U-Net, Res-UNet and UNet++ and compared their performance. We applied pre-processing techniques including wiping the background to lessen interference by YOLOv4 and standardizing image sizes. Also, post-processing techniques such as adding filter for filtering the small effusion areas were used. The Res-UNet algorithm had the best performance with an accuracy of 94.6% for moderate/severe hydronephrosis with substantial recall rate, specificity, precision, F1 measure and intersection over union. The Res-UNet algorithm has the best performance in detection of moderate/severe hydronephrosis. It would decrease variability among sonographers and improve efficiency under clinical conditions.

Breaking the Cycle of Recurrent Calcium Stone Disease

Calcium stones are common and recurrent in nature, yet few therapeutic tools are available for secondary prevention. Personalized approaches for stone prevention have been informed by 24-hour urine testing to guide dietary and medical interventions. However, current evidence is conflicting about whether an approach guided by 24-hour urine testing is more effective than a generic one. The available medications for stone prevention, namely thiazide diuretics, alkali, and allopurinol, are not always prescribed consistently, dosed correctly, or tolerated well by patients. New treatments on the horizon hold the promise of preventing calcium oxalate stones by degrading oxalate in the gut, reprogramming the gut microbiome to reduce oxalate absorption, or knocking down expression of enzymes involved in hepatic oxalate production. New treatments are also needed to target Randall's plaque, the root cause of calcium stone formation.

CT Use Reduction In Ostensive Ureteral Stone (CURIOUS)

INTRODUCTION

Computed tomography (CT) is performed in over 90% of patients diagnosed with ureteral stones, but only 10% of patients presenting to the emergency department (ED) with acute flank pain are hospitalized for a clinically important stone or non-stone diagnosis. Hydronephrosis can be accurately detected using point-of-care ultrasound and is a key predictor of ureteral stone and risk of subsequent complications. The absence of hydronephrosis is insufficient to exclude a stone. We created a sensitive clinical decision rule to predict clinically important ureteral stones. We hypothesized that this rule could identify patients at low risk for this outcome.

METHODS

We conducted a retrospective cohort study in a random sample of 4000 adults who presented to one of 21 Kaiser Permanente Northern California EDs and underwent a CT for suspected ureteral stone from 1/1/2016 to 12/31/2020. The primary outcome was clinically important stone, defined as stone resulting in hospitalization or urologic procedure within 60 days. We used recursive partition analysis to generate a clinical decision rule predicting the outcome. We estimated the C-statistic (area under the curve), plotted the receiver operating characteristic (ROC) curve for the model, and calculated sensitivity, specificity, and predictive values of the model based on a risk threshold of 2%.

RESULTS

Among 4000 patients, 354 (8.9%) had a clinically important stone. Our partition model resulted in four terminal nodes with risks ranging from 0.4% to 21.8%. The area under the ROC curve was 0.81 (95% CI 0.80, 0.83). Using a 2% risk cut point, a clinical decision tree including hydronephrosis, hematuria, and a history of prior stones predicted complicated stones with sensitivity 95.5% (95% CI 92.8%-97.4%), specificity 59.9% (95% CI 58.3%-61.5%), positive predictive value 18.8% (95% CI 18.1%-19.5%), and negative predictive value 99.3% (95% CI 98.8%-99.6%).

CONCLUSIONS

Application of this clinical decision rule to imaging decisions would have led to 63% fewer CT scans with a miss rate of 0.4%. A limitation was the application of our decision rule only to patients who underwent CT for suspected ureteral stone. Thus, this rule would not apply to patients who were thought to have ureteral colic but did not receive a CT because ultrasound or history were sufficient for diagnosis. These results could inform future prospective validation studies.

Spontaneous stone expulsion in patients with history of urolithiasis

Objectives:

To examine differences in the presentation, management, and outcomes of patients admitted to the emergency department (ED) with ureteral stones, with prior history of urolithiasis compared to patients with a first stone event.

Patients and Methods:

Retrospective analysis of patients who visited the ED that were found to have a ureteral stone on CT. Patients were stratified into two groups: without history of urolithiasis (Group 1) and with history of urolithiasis (Group 2).

Results:

Between 2018 and 2020, 778 patients were admitted with ureteral stones. Patients in group 1 presented with a higher mean serum creatinine ( p = 0.02), larger mean stone size ( p < 0.0001), and a higher proportion of proximal ureteral stones ( p < 0.0001) than patients in group 2. The 30 day readmission rate was significantly higher in group 1 ( p = 0.02). Spontaneous stone expulsion was higher in group 2 ( p < 0.0001), whereas the need for endourological procedures was higher in group 1 ( p < 0.0001). On multivariable analysis serum creatinine (OR 0.264, 95% CI 0.091–0.769, p = 0.01) and stone size (OR 0.623, 95% CI 0.503–0.771, p < 0.0001) were associated with a lower spontaneous stone expulsion rate. History of prior endourological procedures (OR 0.225, OR 0.066–0.765, p = 0.01) was associated with a higher spontaneous stone expulsion rate.

Conclusions:

Our data suggests that patients who are first time stone formers present with larger and more proximal ureteral stones, with a lower likelihood of spontaneous stone expulsion and a subsequent need for surgical intervention. Previous stone surgery and not previous stone expulsion was found to be a predictor for spontaneous stone passage.

Deep learning model-assisted detection of kidney stones on computed tomography

Introduction:

The aim of this study was to investigate the success of a deep learning model in detecting kidney stones in different planes according to stone size on unenhanced computed tomography (CT) images.

Materials and Methods:

This retrospective study included 455 patients who underwent CT scanning for kidney stones between January 2016 and January 2020; of them, 405 were diagnosed with kidney stones and 50 were not. Patients with renal stones of 0–1 cm, 1–2 cm, and >2 cm in size were classified into groups 1, 2, and 3, respectively. Two radiologists reviewed 2,959 CT images of 455 patients in three planes. Subsequently, these CT images were evaluated using a deep learning model. The accuracy rate, sensitivity, specificity, and positive and negative predictive values of the deep learning model were determined.

Results:

The training group accuracy rates of the deep learning model were 98.2%, 99.1%, and 97.3% in the axial plane; 99.1%, 98.2%, and 97.3% in the coronal plane; and 98.2%, 98.2%, and 98.2% in the sagittal plane, respectively. The testing group accuracy rates of the deep learning model were 78%, 68% and 70% in the axial plane; 63%, 72%, and 64% in the coronal plane; and 85%, 89%, and 93% in the sagittal plane, respectively.

Conclusions:

The use of deep learning algorithms for the detection of kidney stones is reliable and effective. Additionally, these algorithms can reduce the reporting time and cost of CT-dependent urolithiasis detection, leading to early diagnosis and management.

Effect of age on presentation and outcome in renal colic

Objectives:

To examine the age-related differences in the presentation, management, and outcomes of patients admitted to the emergency department (ED) with ureteral stones.

Patients and methods:

A retrospective analysis of all patients who visited the ED at a single institution that were found to have a ureteral stone on CT. Clinical, laboratory, and imaging parameters were collected, including outcomes. Patients were subdivided into age groups: 18–30, 31–50, 51–70, and >70 years.

Results:

Between January 2018 and December 2020, 778 patients were admitted to the ED with a ureteral stone. About 78% (609) were males and 22% (169) were females. The mean ages were 49.4 (SD 14.4) and 51.6 (SD 15.7) in males and females, respectively ( p = 0.08). Patients in the 36–50 age group, had significantly higher visual analogue scale (VAS) scores ( p < 0.0001). Patients older than 70 years old presented with significantly higher serum creatinine levels ( p < 0.0001), C-reactive protein (CRP) ( p < 0.001) and leukocyte levels ( p = 0.002). These patients were also found to have significantly larger stones (mean size of 6.2 mm (SD 4.8) ( p < 0.0001)) and underwent percutaneous nephrolithotripsy (PCNL) in significantly higher numbers (56.3% vs 43.8%, ( p < 0.0001)). Less than half of the patients older than 50 years were given medical expulsive therapy (MET) with alpha-blockers, compared to more than 50% in the other age groups ( p = 0.002). Spontaneous stone expulsion was noted in 70.2% of the 18–35-year group, 62.4% of the 36–50-year-old group, 51.8% of the 51–70-year-old group, and 37% of the >70-year-old group ( p < 0.0001). The ED re-admission rates at 7 and 30 days were not significantly different among all age groups.

Conclusions:

Our data suggests that older patients presented with larger stones, elevated inflammatory markers and creatinine and were more likely to require surgical intervention. The spontaneous stone expulsion rate was inversely associated with age.

Effect of an ultrasound-first clinical decision tool in emergency department patients with suspected nephrolithiasis: A randomized trial

INTRODUCTION

Previously, we found that the use of ultrasonography for patients with suspected nephrolithiasis resulted in similar outcomes and less radiation exposure vs. CT scan. In this study, we evaluated the implementation of an ultrasound-first clinical decision support (CDS) tool in patients with suspected nephrolithiasis.

METHODS

This randomized trial was conducted at an academic emergency department (ED). We implemented the ultrasound-first CDS tool, deployed when an ED provider placed a CT order for suspected nephrolithiasis. Providers were randomized to receiving the CDS tool vs. usual care. The primary outcome was receipt of CT during the index ED visit. Secondary outcomes included radiation dose and ED revisit.

RESULTS

64 ED Providers and 254 patients with suspected nephrolithiasis were enrolled from January 2019 through Dec 2020. The US-First CDS tool was deployed for 128 patients and was not deployed for 126 patients. 86.7% of patients in the CDS arm received a CT vs. 94.4% in the usual care arm, resulting in an absolute risk difference of -7.7% (-14.8 to -0.6%). Mean radiation dose in the CDS arm was 6.8 mSv (95% CI 5.7-7.9 mSv) vs. 6.1 mSv (95% CI 5.1-7.1 mSv) in the usual care arm. The CDS arm did not result in increased ED revisits, CT scans, or hospitalizations at 7 or 30 days.

CONCLUSIONS AND RELEVANCE

Implementation of the US-first CDS tool resulted in lower CT use for ED patients with suspected nephrolithiasis. The use of this decision support may improve the evaluation of a common problem in the ED.

TRIAL REGISTRATION

ClinicalTrials.gov#NCT03461536.

Imaging in stone diagnosis and surgical planning

PURPOSE OF REVIEW

Radiological imaging techniques and applications are constantly advancing. This review will examine modern imaging techniques in the diagnosis of urolithiasis and applications for surgical planning.

RECENT FINDINGS

The diagnosis of urolithiasis may be done via plain film X-ray, ultrasound (US), or contrast tomography (CT) scan. US should be applied in the workup of flank pain in emergency rooms and may reduce unnecessary radiation exposure. Low dose and ultra-low-dose CT remain the diagnostic standard for most populations but remain underutilized. Single and dual-energy CT provide three-dimensional imaging that can predict stone-specific parameters that help clinicians predict stone passage likelihood, identify ideal management techniques, and possibly reduce complications. Machine learning has been increasingly applied to 3-D imaging to support clinicians in these prognostications and treatment selection.

SUMMARY

The diagnosis and management of urolithiasis are increasingly personalized. Patient and stone characteristics will support clinicians in treatment decision, surgical planning, and counseling.

Ultrasound versus fluoroscopy-guided ureteroscopy for distal ureteric stones in adults

Objective

To evaluate the safety and efficacy of ultrasound (US) as alternative to fluoroscopy for guidance of ureteroscopy (URS) during treatment of distal ureteric stones in adults.

Materials and methods

This study enrolled 80 patients older than 18 years presented with a single distal ureteric radio-opaque stone of ≤15 mm in longest diameter. Patients were randomized and allocated into two groups: the fluoroscopy group and the ultrasound group (n = 40 patients in each group). Patients with bilateral ureteric stones, solitary kidney, ureteric congenital anomalies, history of failed ureteroscopy, history of ureteric surgery, patients with uremia and pregnant women were excluded. Patients’ demographics, stone characteristics, operative data, stone-free status, hospital stay and complications were evaluated in both groups.

Results

No statistically significant difference between both groups was found regarding patients’ demographics and stone characteristics. Also there was no statistically significant difference in comparing fluoroscopy group versus ultrasound group regarding operative time (29.48 ± 15.3 versus 31.28 ± 18.24 min; P = 0.83), stone-free rate (97.5% versus 95%; P = 1.0), overall complications (15% versus 12.5%; P = 0.75), or hospital stay (1.17 ± 0.6 versus 1.02 ± 0.16 days; P = 0.12). Four patients (10%) in the ultrasound group required the addition of fluoroscopy beside ultrasound.

Conclusion

Ultrasound is effective in guidance during ureteroscopy for distal ureteric stones. It was comparable to fluoroscopy in terms of stone free rate, operative time, overall complications, and hospital stay. However, fluoroscopy must be available to be used when needed.

Use of STONE Score to Predict Urolithiasis in an Asian Emergency Department

BACKGROUND

The STONE score was developed to predict uncomplicated ureteral stones in patients so that they can be managed without imaging. Validation studies had been conducted previously but the results were varied. This study aims to investigate the utility of the STONE score in an emergency department in Singapore.

METHODS

We retrospectively analyzed the records of adult patients presenting with ureteric colic in the emergency department in 2015. STONE score as well as the proportion of urolithiasis diagnosed on advanced imaging in each STONE score group were calculated. Logistic regression was used to calculate the odds ratios (ORs) for the STONE score components in our study and compared with the ORs obtained in the original study. Measures of diagnostic accuracy for a high STONE score were also calculated.

RESULTS

753 cases were included in the final analysis. Among patients with a high STONE score, 66.7% had urolithiasis and 2.6% had significant alternative diagnoses. Compared to original studies, ORs for the STONE score components obtained for our study were different. From our study, the sensitivity of a high STONE score was 47.0%, specificity was 68.7%, positive predictive value was 66.7%, negative predictive value was 49.3%, positive likelihood ratio was 1.50, and negative likelihood ratio was 0.77.

CONCLUSION

The STONE score is not expected to perform well in Singapore based on our study. It should be used with caution in similar Asian populations.

A deep learning system for automated kidney stone detection and volumetric segmentation on noncontrast CT scans

PURPOSE

Early detection and size quantification of renal calculi are important for optimizing treatment and preventing severe kidney stone disease. Prior work has shown that volumetric measurements of kidney stones are more informative and reproducible than linear measurements. Deep learning-based systems that use abdominal noncontrast computed tomography (CT) scans may assist in detection and reduce workload by removing the need for manual stone volume measurement. Prior to this work, no such system had been developed for use on noisy low-dose CT or tested on a large-scale external dataset.

METHODS

We used a dataset of 91 CT colonography (CTC) scans with manually marked kidney stones combined with 89 CTC scans without kidney stones. To compare with a prior work half the data was used for training and half for testing. A set of CTC scans from 6185 patients from a separate institution with patient-level labels were used as an external validation set. A 3D U-Net model was employed to segment the kidneys, followed by gradient-based anisotropic denoising, thresholding, and region growing. A 13 layer convolutional neural network classifier was then applied to distinguish kidney stones from false positive regions.

RESULTS

The system achieved a sensitivity of 0.86 at 0.5 false positives per scan on a challenging test set of low-dose CT with many small stones, an improvement over an earlier work that obtained a sensitivity of 0.52. The stone volume measurements correlated well with manual measurements (r 2 = 0.95 $r^2 = 0.95$ ). For patient-level classification, the system achieved an area under the receiver-operating characteristic of 0.95 on an external validation set (sensitivity = 0.88, specificity = 0.91 at the Youden point). A common cause of false positives were small atherosclerotic plaques in the renal sinus that simulated kidney stones.

CONCLUSIONS

Our deep-learning-based system showed improvements over a previously developed system that did not use deep learning, with even higher performance on an external validation set.

National trends and prescription patterns in opiate analgesia for urolithiasis presenting to Emergency Departments: Analysis of the National Hospital Ambulatory Medical Care Survey, 2006-2018

OBJECTIVE

To analyze the National Hospital Ambulatory Medical Care Survey (NHAMCS) database to determine geographic and temporal trends, as well as variables associated with the likelihood of receiving an opioid prescription for urolithiasis in US EDs.

METHODS

All ED visits for urolithiasis between 2006-2018 in the NHAMCS database were analyzed. Age, race/ethnicity, insurance status, ED provider credentials, geographic region, and urban vs. rural hospital status were extracted. Linear regression was used to examine overall/regional trends in opioid prescriptions over time. Logistic regression was used to estimate factors associated with higher odds of receiving opioids.

RESULTS

Fourteen million visits were analyzed, of which, 79.1% (11.0 million) received an opioid prescription. From 2014-2018 there was a decline of 3.65%/year of the proportion of visits receiving an opioid prescription (R²=0.86, p=0.008). Non-Hispanic Black race was associated with a lower chance of receiving opioid prescription (OR=0.57, p=0.02) compared to Non-Hispanic Whites (NHW). Midwestern hospitals had higher odds of opioid prescription compared to the Northeast (OR=2.05, p=0.006). Rural hospitals had lower odds of opioid prescription compared to urban hospitals (OR=0.62, p=0.02).

CONCLUSION

Opioid prescriptions for patients presenting with urolithiasis to the ED have steadily declined from 2014-2018, except in the Midwest. NHW race, Midwest region, and urban EDs increase the likelihood of receiving opioids. Continued efforts encouraging non-opioid alternatives for urolithiasis are essential, specifically in Midwestern EDs, to mitigate the ongoing opioid epidemic in the US.

Association between aortic calcification and the presence of kidney stones: calcium oxalate calculi in focus

PURPOSE

The current research is aimed at analyzing the relationship between kidney stone (KS) and abdominal aortic calcification (AAC) and the relationship between KS components and AAC.

METHODS

This is a retrospective, case-control study. Kidney stone formers (KSFs) were treated at the Department of Urology, West China Hospital, Sichuan University for urological calculus disease from January 2014 to January 2020. Matched non-stone formers (non-SFs) were drawn from the same hospital for routine health examination from January 2018 to February 2019. Research-related information was collected and reviewed retrospectively from the hospital's computerized records. AAC were evaluated using available results of computed tomography imaging and abdominal vascular ultrasound. The relationships of AAC between KSFs and non-SFs were compared. The composition of renal calculi was analyzed by Fourier-transform infrared spectrophotometer. KSFs were divided into AAC groups and non-AAC based on AAC. The relationship of the composition of renal calculi between AAC and non-AAC were compared. The independent-sample t test, the chi-squared test and binary logistics regression were performed.

RESULTS

Altogether, 4516 people were included, with 1027 KSFs and 3489 non-SFs. There were no significant differences in the laboratory parameters between KSFs and non-SFs. The association between the presence of AAC and KS was significant in multivariable model 2 [adjusting hypertension, diabetes mellitus, fasting blood glucose, uric acid, serum triglyceride (TG), serum calcium, and urine pH] (OR 5.756, 95% CI 4.616-7.177, p < 0.001). The result of KSFs showed that calcium oxalate calculi (CaOx) was significantly associated with AAC in multivariable model 3 (adjusting age, hypertension, diabetes mellitus, drinking history, smoking history, and TG) (OR 1.351, 95% CI 1.002-1.822, p = 0.048).

CONCLUSIONS

The current study pioneered the revelation of the relationship between CaOx and AAC. Through an elimination of the confounding factors, the study demonstrated that KS and AAC were connected.

Cone beam computed tomography for detecting residual stones in percutaneous nephrolithotomy, a randomized controlled trial (CAPTURE) protocol

Introduction

Percutaneous nephrolithotomy (PCNL) is the standard surgical treatment method for large kidney stones. Its aim is to achieve a stone-free status, since any residual fragments (RFs) after PCNL are likely to cause additional morbidity or stone growth. Enhancing intraoperative detectability of RFs could lead to increased stone-free rates and decreased re-intervention rates. Cone beam computed tomography (CBCT) has recently been introduced in urology as a feasible method for intraoperatively imaging RFs. The aim of this trial is to determine the added value of CBCT in percutaneous nephrolithotomy, by measuring differences in stone-related morbidity for patients with procedures in which a CBCT is used versus patients with procedures without the use of CBCT.

Methods

The CAPTURE trial is an investigator-initiated single-center, randomized controlled trial (RCT) in adult patients who have an indication for percutaneous nephrolithotomy. A contemporary percutaneous nephrolithotomy is performed. Once the surgeon is convinced of a stone-free status by means of fluoroscopy and nephroscopy, randomization allocates patients to either the study group in whom an intraoperative CBCT scan is performed or to the control group in whom no intraoperative CBCT scan is performed. The main endpoint is the stone-free status as assessed four weeks postoperatively by low-dose non-contrast abdominal CT, as a standard follow-up procedure. Secondary endpoints include the number of PCNL procedures required and the number of stone-related events (SREs) registered. The total study population will consist of 320 patients that undergo PCNL and are eligible for randomization for an intraoperative CBCT scan.

Discussion

We deem a randomized controlled trial to be the most effective and reliable method to assess the efficacy of CBCT in PCNL. Though some bias may occur due to the impossibility of blinding the urologist at randomization, we estimate that the pragmatic nature of the study, standardized circumstances, and follow-up methods with pre-defined outcome measures will result in a high level of evidence.

Trial registration

Netherlands Trial Register (NTR) NL8168, ABR NL70728.042.19. Registered on 15 October 2019. Prospectively registered.

Twenty-four-hour Urine Testing and Urinary Stone Disease Recurrence in Veterans

OBJECTIVE

To determine whether 24-hour urine testing in Veterans with USD (urinary stone disease) reduces or delays urinary stone recurrence.

METHODS

Cohort study of national health record data from Veterans Health Administration from 2007 through 2013. We utilized a study population of 130,129 Veterans with USD based on diagnostic or procedural codes and excluded those with USD claims in the 2 years before cohort entry. We then created a propensity-score matched cohort of 14,854 Veterans based on completion of 24-hour urine testing within 6 months of stone diagnosis. Primary outcome was time-to-next clinically significant stone event, defined as an emergency department visit, inpatient admission related to a urinary stone, or urologic stone procedure with 5-year follow up.

RESULTS

Of 14,854 Veterans in the propensity-score matched cohort, 8560 (57.6%) experienced a recurrent USD event. Completion of 24-hour urine testing was associated with a higher risk of developing a second stone event (hazard ratio [HR] 1.17, 95% confidence interval [95% CI] 1.12-1.22). Among Veterans with known recurrent disease, we examined time to a third stone event. In this cohort of 4736 patients, completion of 24-hour urine testing was not associated with a higher risk of developing a third stone event (HR 1.06, 95% CI 0.99-1.12).

CONCLUSION

Completion of 24-hour urine testing was not associated with a reduction in urinary stone recurrence. These findings challenge the validity of a longstanding recommendation in general medicine, nephrology, and urology practice.

Opioid Analgesics and Persistent Pain After an Acute Pain Emergency Department Visit: Evidence from a Cohort of Suspected Urolithiasis Patients

BACKGROUND

Severe acute pain is still commonly treated with opioid analgesics in the United States, but this practice could prolong the duration of pain.

OBJECTIVES

Estimate the risk of experiencing persistent pain after opioid analgesic use after emergency department (ED) discharge among patients with suspected urolithiasis.

METHODS

We analyzed data collected for a longitudinal, multicenter clinical trial of ED patients with suspected urolithiasis. We constructed multilevel models to estimate the odds ratios (ORs) of reporting pain at 3, 7, 30, or 90 days after ED discharge, using multiple imputation to account for missing outcome data. We controlled for clinical, demographic, and institutional factors and used weighting to account for the propensity to be prescribed an opioid analgesic at ED discharge.

RESULTS

Among 2413 adult ED patients with suspected urolithiasis, 62% reported persistent pain 3 days after discharge. Participants prescribed an opioid analgesic at discharge were OR 2.51 (95% confidence interval [CI] 1.82-3.46) more likely to report persistent pain than those without a prescription. Those who reported using opioid analgesics 3 days after discharge were OR 2.24 (95% CI 1.77-2.84) more likely to report pain at day 7 than those not using opioid analgesics at day 3, and those using opioid analgesics at day 30 had OR 3.25 (95% CI 1.96-5.40) greater odds of pain at day 90.

CONCLUSIONS

Opioid analgesic prescription doubled the odds of persistent pain among ED patients with suspected urolithiasis. Limiting opioid analgesic prescribing at ED discharge for these patients might prevent persistent pain in addition to limiting access to these medications.

Radiation risk issues in recurrent imaging

Millions of patients benefit from medical imaging every single day. However, we have entered an unprecedented era in imaging practices wherein 1 out of 125 patients can be exposed to effective dose >50 mSv from a single CT exam and 3 out of 10,000 patients undergoing CT exams could potentially receive cumulative effective doses > 100 mSv in a single day. Recurrent imaging with CT, fluoroscopically guided interventions, and hybrid imaging modalities such as positron emission tomography/computed tomography (PET/CT) is more prevalent today than ever before. Presently, we do not know the cumulative doses that patients may be receiving across all imaging modalities combined. Furthermore, patients with diseases with longer life expectancies are being exposed to high doses of radiation enabling radiation effects to manifest over a longer time period. The emphasis in the past on improving justification of imaging and optimization of technique and practice has proved useful. While that must continue, the current situation requires imaging device manufacturers to urgently develop imaging technologies that are safer for patients as high doses have been observed in patients where imaging has been justified through clinical decision-support and optimized by keeping doses below the national benchmark doses. There is a need to have a critical look at the fundamental principles of radiation protection as cumulative doses are likely to increase in the coming years.

Low-dose dual-energy CT for stone characterization: a systematic comparison of two generations of split-filter single-source and dual-source dual-energy CT

PURPOSE

To compare noise texture and accuracy to differentiate uric acid from non-uric acid urinary stones among four different single-source and dual-source DECT approaches in an ex vivo phantom study.

METHODS

Thirty-two urinary stones embedded in gelatin were mounted on a Styrofoam disk and placed into a water-filled phantom. The phantom was imaged using four different DECT approaches: (A) dual-source DECT (DS-DE); (B) 1st generation split-filter single-source DECT (SF1-TB); (C) 2nd generation split-filter single-source DECT (SF2-TB) and (D) 2nd generation split-filter single-source DECT using serial acquisitions (SF2-TS). Two different radiation doses (3 mGy and 6 mGy) were used. Noise texture was compared by assessing the average spatial frequency (f_av) of the normalized noise power spectrum (nNPS). ROC curves for stone classification were computed and the accuracy for different dual-energy ratio cutoffs was derived.

RESULTS

NNPS demonstrated comparable noise texture among A, C, and D (f_av-range 0.18-0.19) but finer noise texture for B (f_av = 0.27). Stone classification showed an accuracy of 96.9%, 96.9%, 93.8%, 93.8% for A, B, C, D for low-dose, respectively, and 100%, 96.9%, 96.9%, 100% for routine dose. The vendor-specified cutoff for the dual-energy ratio was optimal except for the low-dose scan in D for which the accuracy was improved from 93.8 to 100% using an optimized cutoff.

CONCLUSION

Accuracy to differentiate uric acid from non-uric acid stones was high among four single-source and dual-source DECT approaches for low- and routine dose DECT scans. Noise texture differed only slightly for the first-generation split-filter approach.

Prediction of burden and management of renal calculi from whole kidney radiomics: a multicenter study

Purpose

To assess if autosegmentation-assisted radiomics can predict disease burden, hydronephrosis, and treatment strategies in patients with renal calculi.

Methods

The local ethical committee-approved, retrospective study included 202 adult patients (mean age: 53 ± 17 years; male: 103; female: 99) who underwent clinically indicated, non-contrast abdomen-pelvis CT for suspected or known renal calculi. All CT examinations were reviewed to determine the presence (n = 123 patients) or absence (n = 79) of renal calculi. On CT images with renal calculi, each kidney stone was annotated and measured (maximum dimension, Hounsfield unit (HU), and combined and dominant stone volumes) using a HU threshold-based segmentation. We recorded the presence of hydronephrosis, number of renal calculi, and treatment strategies. Deidentified CT images were processed with the radiomics prototype (Radiomics, Frontier, Siemens Healthineers), which automatically segmented each kidney to obtain 1690 first-, shape-, and higher-order radiomics. Data were analyzed using multiple logistic regression analysis with areas under the curve (AUC) as output.

Results

Among 202 patients, only 28 patients (18%) needed procedural treatment (lithotripsy or ureteroscopic stone extraction). Gray-level co-occurrence matrix (GLCM) and gray-level run length matrix (GLRLM) differentiated patients with and without procedural treatment (AUC 0.91, 95% CI 0.85–0.92). Higher-order radiomics (gray-level size zone matrix – GLSZM) differentiated kidneys with and without hydronephrosis (AUC: 0.99, p < 0.001) as well those with different stone volumes (AUC up to 0.89, 95% CI 0.89–0.92).

Conclusion

Automated segmentation and radiomics of entire kidneys can assess hydronephrosis presence, stone burden, and treatment strategies for renal calculi with AUCs > 0.85.

Analgesic and Opioid Use for Patients Discharged from the Emergency Department with Ureteral Stones

Objective: The aim of this study was to describe and characterize the analgesic and opioid use for patients discharged from the emergency department (ED) with renal colic due to ureteral stone. Methods: This is a secondary analysis of a multicenter prospective trial of ED patients diagnosed by CT scan as having a symptomatic ureteral stone <9 mm in diameter. Participants were contacted after randomization on days 2, 7, 15, 20, and 29 and reported opioid and nonopioid analgesic use and stone passage. CT scan was repeated on day 29 to 36 to confirm passage. Results: Of 403 participants, 314 (77.9%) took an analgesic after discharge and 199 (49.4%) took opioids. Opioids were more commonly used by younger patients (p = 0.04) and those with a family history of stones (p = 0.003). Stone size and tamsulosin use were not associated with analgesic utilization. Shorter time to passage and more distal stone location were associated with less analgesic and opioid use. For those who did not expel a stone, 55.0% took opioids at any time, and for those who did expel a stone, 31.9% took opioids before the stone was expelled and 15.7% took opioids at any time after the stone was expelled. Conclusions: Factors associated with increased use of analgesics in patients discharged from the ED include a longer time to stone passage, no spontaneous passage, and proximal position of the stone in the ureter. Some patients continued to use analgesics after the stone had passed, but most stopped using analgesics by day 29. The study has been registered at https://clinicaltrials.gov (NCT00382265).

Adherence to guidelines in the management of urolithiasis: are there differences among distinct patient care settings?

INTRODUCTION

Urolithiasis is a common diagnosis in urology. New technologies offer a variety of diagnostic and therapy and consequently display a financial burden on healthcare systems. Hence, clinical practice guidelines (CPG) are essential to implement evidence-based medicine and assure a standard of care considering limited resources. To date, there is no evidence of the use and adherence to CPG on urolithiasis.

MATERIAL AND METHODS

Therefore, we performed a cross-sectional study to analyze the use of CPG on urolithiasis. Data collection was carried out by a questionnaire given to 400 German urologists. The survey included use and adherence to guidelines, evaluation of the clinical situation, therapy spectrum, and workplace. In total, 150 (37%) questionnaires were received and included in our survey. Statistics were performed by SPSS using Chi-quadrat test/Fisher's exact test.

RESULTS

In our study, urologists were office based, hospital affiliated, non-academic, or academic centers in 53%, 32%, 16% and 5%, respectively. In 74% and 70%, urologists adhere to CPG in diagnostic and therapy. Interestingly, workplace and therapy spectrum determines the use of different CPG (p = 0.01; p = 0.022). Academic urologists were more likely to use international CPG of EAU (40%), while outpatient urologists significantly orientated on national CPG (46%). 86% of urologists with high volume of urolithiasis practice interventions in contrast to 53% in low volume (p = 0.001). More than 80% of urologists use short versions and app version of CPG.

CONCLUSION

We firstly describe compliance and the use of CPG on urolithiasis. EAU and DGU present the most commonly used CPG. Short version and app version of CPG find frequent clinical utilization.

Intravenous Paracetamol vs Intranasal Desmopressin for Renal Colic in the Emergency Department: A Randomized Clinical Trial

OBJECTIVE

To evaluate the analgesic efficacy of intranasal desmopressin alone vs intravenous paracetamol in patients referred to the emergency department with renal colic.

DESIGN

Randomized clinical trial.

SETTING

This study was conducted in the emergency unit of a university hospital.

SUBJECTS

Patients referred to the emergency room with renal colic.

PRIMARY OUTCOME

Effect of intranasal desmopressin in pain relief in comparison with intravenous paracetamol.

METHODS

In this trial, 240 patients diagnosed with renal colic were randomly divided into two groups to compare the analgesic effect of intravenous paracetamol (15 mg/kg) and intranasal desmopressin spray (40 μg). Pain scores were measured by a numeric rating scale at baseline and after 15, 30, and 60 minutes. Adverse effects and need for rescue analgesic (0.05 mg/kg max 3 mg morphine sulphate) were also recorded at the end of the study.

RESULTS

Three hundred patients were eligible for the study; however, 240 were included in the final analysis. The patients in the two groups were similar in their baseline characteristics and baseline pain scores. The mean pain score after 15 minutes was more reduced and was clinically significant (>3) in the desmopressin group (P < 0.0001). There was no significant difference between mean pain scores in the two groups after 30 minutes (P = 0.350) or 60 minutes (P = 0.269), but the efficacy of the two drugs was significant in terms of pain reduction (>6).

CONCLUSIONS

Our study showed that intranasal desmopressin is as effective as intravenous paracetamol for renal colic pain management; however, significant clinical reduction in pain score occurred faster with intranasal desmopressin.

Development of a Portable Multi-Sensor Urine Test and Data Collection Platform for Risk Assessment of Kidney Stone Formation

In this paper, we present an Internet of things (IoT)-based data collection system for the risk assessment of urinary stone formation, or urolithiasis, by the measurement and storage of four parameters in urine: pH, concentrations of ionized calcium (Ca2+), uric acid and total dissolved solids. The measurements collected by the system from patients and healthy individuals grouped by age and gender will be stored in a cloud database. These will be used in the training phase of an artificial intelligence (AI) machine learning process utilizing the logistics regression model. The trained model provides a binary risk assessment, indicating if the end user is either a stone-former or not. For system validation, standard chemical solutions were used. Preliminary results indicated a sufficient measurement range, falling within the physiological range, and resolution for pH (2.0–10.0, +/−0.1), Ca2+(0.1–3.0 mmol/l, +/−0.05), uric acid (20–500 ppm, +/−1) and conductivity (1.0–40.0 mS/cm, +/−0.1), exhibiting high correlation with standard instruments. We intend to deploy this system in few hospitals in Taiwan to collect the data of patients’ urine, with analysis aided by urologist assessments for the risk of urolithiasis. The modularized design allows future modification and expansion to accommodate other sensing analytes.

Application of decision rules on diagnosis and prognosis of renal colic: a systematic review and meta-analysis

Renal colic is a prevalent emergency department presentation resulting from urolithiasis. Clinical decision rules for the diagnosis of urolithiasis were developed to help clinicians with better judgment. In this systematic review, we assessed the performance of prediction rules on urolithiasis diagnosis and prognosis. MEDLINE, Embase, Web of Science, and Scopus were searched for studies on the performance of a clinical decision tool for diagnosis or prognosis of urolithiasis. Performance and accuracy of the rules were the key outcomes of interest. Databases were searched from inception to March 2019. Of the 4980 articles reviewed, 28 studies were included in the present analysis. Twenty-one studies were on urolithiasis diagnosis (including eight studies on STONE rule), and 10 studies reported urolithiasis outcomes. Studies were at low to moderate risk of bias. The pooling of data on STONE showed that the prevalence of urolithiasis in low, moderate, and high risk groups were: 12% (95% confidence interval 9%-15%), 53% (95% confidence interval 43%-62%), and 83% (95% confidence interval 75%-91%), respectively. In the high risk score group, prevalence of clinically important alternative diagnosis was 1% (95% confidence interval 0%-2%) and 11% (95% confidence interval 8%-13%) of patients needed intervention. STONE scoring system is useful in estimating the prevalence of urolithiasis but high heterogeneity among the studies makes it unsuitable for application. Other decision tools were poorly studied and cannot be recommended for clinical use.

Dual-Energy CT for Urinary Stone Evaluation

PURPOSE OF REVIEW

Conventional CT imaging is an excellent tool for the diagnosis of nephrolithiasis however is limited in its ability to detect stone composition. Dual-energy CT (DECT) scans have demonstrated promise in overcoming this limitation. We review the current utility of DECT in nephrolithiasis.

RECENT FINDINGS

DECT is superior to conventional CT in differentiating uric acid stones from non-uric acid stones, with numerous studies reporting sensitivities and specificities approaching > 95%. Dose reduction protocols incorporating low-dose CT scans are commonly used, providing significantly lower effective radiation doses compared to conventional CT. DECT remains an effective diagnostic tool in patients with large body habitus. DECT can accurately detect uric acid stones, which can help guide which stones may be suitable to medical dissolution. Further studies evaluating the effectiveness of DECT in guiding management of patients with nephrolithiasis can help to promote its widespread use.

Prevention of Urinary Stones With Hydration (PUSH): Design and Rationale of a Clinical Trial

RATIONALE & OBJECTIVE

Although maintaining high fluid intake is an effective low-risk intervention for the secondary prevention of urinary stone disease, many patients with stones do not increase their fluid intake.

STUDY DESIGN

We describe the rationale and design of the Prevention of Urinary Stones With Hydration (PUSH) Study, a randomized trial of a multicomponent behavioral intervention program to increase and maintain high fluid intake. Participants are randomly assigned (1:1 ratio) to the intervention or control arm. The target sample size is 1,642 participants.

SETTING & PARTICIPANTS

Adults and adolescents 12 years and older with a symptomatic stone history and low urine volume are eligible. Exclusion criteria include infectious or monogenic causes of urinary stone disease and comorbid conditions precluding increased fluid intake.

INTERVENTIONS

All participants receive usual care and a smart water bottle with smartphone application. Participants in the intervention arm receive a fluid intake prescription and an adaptive program of behavioral interventions, including financial incentives, structured problem solving, and other automated adherence interventions. Control arm participants receive guideline-based fluid instructions.

OUTCOMES

The primary end point is recurrence of a symptomatic stone during 24 months of follow-up. Secondary end points include changes in radiographic stone burden, 24-hour urine output, and urinary symptoms.

LIMITATIONS

Periodic 24-hour urine volumes may not fully reflect daily behavior.

CONCLUSIONS

With its highly novel features, the PUSH Study will address an important health care problem.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT03244189.

Transversus abdominis plane block: A new method in renal colic pain management

In recent decades, regional plane blocks via ultrasonography have become very popular in regional anesthesia and are more commonly used in pain management. The transversus abdominis plane (TAP) block is a procedure where local anesthetics are applied to block the anterior divisions of the tenth thoracic intercostal through the first lumbar nerves (T10-L1) into the anatomic space formed amidst the internal oblique and transversus abdominis muscles located in the antero-lateral part of the abdomen wall. The most important advantage of this block method is that ultrasonographic identification is easier and its complications are fewer compared with central neuroaxial or paravertebral blocks. Here, we describe three cases where pain management in renal colic was treated with the TAP block.

Imaging strategies for patients with suspicion of uncomplicated colic pain: diagnostic accuracy and management assessment

OBJECTIVE

Compare different imaging scenarios in the diagnosis of uncomplicated renal colic due to urolithiasis (URCU).

MATERIALS AND METHODS

A total of 206 prospectively included patients had been admitted with suspected URCU and had undergone abdominal plain film (APF), US and unenhanced CT after clinical STONE score evaluation. CT was the reference standard. We assessed sensitivity (Se), specificity (Spe) and Youden index for colic pain diagnosis, percentage of patients managed by urologic treatment with stone identified, percentage of alternative diagnoses (AD) and exposure to radiation, according to single imaging approaches, strategies driven by patient characteristics and conditional imaging strategies after APF and US.

RESULTS

One hundred (48.5%) patients had a final diagnosis of URCU and 19 underwent urologic treatment. The conditional strategy, i.e. CT in patients who had no stone identified at US, had a perfect sensitivity and specificity. This enabled diagnosis of all stones requiring urology management while decreasing the number of CT exams by 22%. The strategy whereby CT was used when there was neither direct or indirect APF + US finding of colic pain nor alternative diagnoses in patients with a STONE score ≥ 10 had a sensitivity of 0.95 and a specificity of 0.99, identified 84% of stones managed by urologic treatment and decreased the number of CT examinations by 76%.

CONCLUSION

In patients with clinical findings consistent with URCU, the use of ultrasound as first-line imaging modality, with CT restricted to patients with negative US and a STONE score ≥ 10, led to a sensitivity and specificity of above 95%, identified 84% of stones requiring urological management and reduced the number of CT scans needed by fourfold.

KEY POINTS

• For diagnosis, the use of APF + US as first-line imaging, with CT restricted to patients with both a normal APF + US and a STONE score ≥ 10, provides both a sensitivity and specificity superior or equal to 95% and reduces the number of CT scans necessary by fourfold. • For management, the use of APF + US as first-line imaging, with CT restricted to patients with both a normal APF + US and a STONE score ≥ 10, maintains a 84% stone identification rate in urology-treated patients.

SONO case series: 35-year-old male patient with flank pain

The diagnosis and management of obstructing nephrolithiasis by emergency physicians has undergone great advancements in the past few years. No longer do all patients with suspected renal colic need a CT scan and an immediate urology consult. In this case presentation, we present a classic case of obstructing nephrolithiasis along with the associated point-of-care ultrasound images. We will walk with the reader through a series of questions and answers discussing the patient's diagnosis based on the most current evidence-based recommendations.

Urethral Calculi

Urolithiasis is a condition with calculi commonly found within the kidney, ureter, or bladder. The urethra is an uncommon location of urolithiasis, with limited case reports and literature reviews of its presentation and management. Here we discuss a 24-year-old female who presented with urinary urgency, flank pain, and urinary retention for 12 hours. Physical exam showed a calculus at the urethral meatus. This case discusses the manual removal of a urethral calculus in a female patient with use of forceps, resulting in complete resolution of symptoms and urinary retention.

Derivation of a clinical predicting rule for obstructive urolithiasis and alternative diagnosis requiring urgent intervention: the CLAD score

Most patients with renal colic are discharged from the emergency department (ED) after evaluation and pain alleviation. These patients may not require urgent imaging by computed tomography. We derived a clinical prediction score in patients with renal colic to identify those at very low risk for complications and alternative diagnoses requiring urgent intervention. This retrospective chart review was carried out in 2 ED at an urban university hospital from January to December 2015. All patients with a diagnosis of renal colic were included. The primary outcome was an intervention required for renal colic or alternative diagnoses within 7 days of ED presentation. A stepwise logistic regression was used to assess factors associated with the outcome. A score was derived as a weighted sum of these predictors and its performance was calculated. The database was submitted to the French National Commission for Data Protection and Liberties (CNIL): declaration n°2164898v0 (03/22/2018). 871 with complete data were analyzed. In 94 (11%) patients, an intervention was performed for obstructive urolithiasis or alternative diagnosis. Five factors were most predictive of intervention: age > 45 years (1 point), a history of urologic surgery (1 point), pulse > 100 bpm (1 point), temperature > 37.8 °C (2 point), and urine dipstick negative for blood (1 point), yielding a score of 0-6 points (the Complicated uroLithiasis and Alternative Diagnosis (CLAD) score). The area under the curve of the receiver operating characteristic curve was 0.82 (95% CI 0.77-0.87). We derived a clinical score for renal colic that predicted the presence of obstructive urolithiasis and acute alternative diagnoses requiring intervention.

Development and validation of a score for emergency intervention in patients with acute renal colic secondary to ureteric stones

Objectives: To develop and validate a scoring system to assess the need for emergency intervention (EI) in patients with uncomplicated acute renal colic (ARC) due to ureteric stones. Patients and methods: From May 2017 to April 2019, 382 adult patients presented to emergency department with ARC due to ureteral stones diagnosed by non-contrast computed tomography. Patients with solitary kidney, complications secondary to obstruction (intractable vomiting, fever or sepsis), bilateral ureteric stones, Stage ≥3 chronic kidney disease or those who underwent treatment of urolithiasis within the past 6 months were excluded. EI was performed in cases with persistent or recurrent pain despite analgesics. Multivariate analysis was performed for the first 200 patients to detect risk factors for EI. The score was developed from significant factors. Sensitivity and specificity of the ARC score were calculated using receiver operator characteristic (ROC) curve analysis. The data of last 182 patients were used for validation of the score. Results: In the first 200 patients, EI was needed in 119 patients (59.5%) and included ureteric stents in 92, ureteroscopy in 25 and percutaneous nephrostomy in two. Significant factors for EI were stone location (relative risk [RR] 3.34, P = 0.026), creatinine level (RR 1.04, P < 0.001), leucocyte count (RR 1.69, P < 0.001), and stone length (RR 1.85, P < 0.001). A score using these four variables was developed. The ARC score sensitivity was 86%, specificity was 80% and the area under the ROC curve was 0.902. Validation of the score showed strong correlation between ARC score and need for EI (r = 0.788, P < 0.001). Conclusions: The ARC score is a validated, highly sensitive and specific novel score to determine the need for EI in patients with uncomplicated ARC secondary to ureteric stones. Abbreviations: ARC: acute renal colic; AUC: area under the ROC curve; CDR: clinical decision rules; CKD: chronic kidney disease; ED: emergency department; EI: emergency intervention; MET: medical expulsive therapy; NCCT: non-contrast CT; PCNL, percutaneous nephrolithotomy; ROC: receiver operator characteristic; S.T.O.N.E.: stone size (S), tract length (T), obstruction (O), number of involved calyces (N), and essence or stone density (E); SWL: extracorporeal shockwave lithotripsy; URS: ureteroscopy; WBC: white blood cell.

Water for preventing urinary stones

BACKGROUND

Urinary stone disease is a common condition characterised by increasing prevalence and high rates of recurrence. Observational studies have reported that increased water intake played a role in the prevention of urinary stone formation but with limited strength of evidence.

OBJECTIVES

To compare the effects of increased water intake with standard water intake for the prevention of urinary stone formation in participants with or without a history of urinary stones.

SEARCH METHODS

We performed a systematic search of PubMed (MEDLINE), EMBASE (Ovid) and the Cochrane Library to 15 October 2019. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles. We did not apply any restrictions to publication language or publication status.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs looking at the benefits and harms of increased water intake versus standard water intake for the prevention of urinary stone formation in participants with or without a history of urinary stones.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently extracted data and assessed the risk of bias of included studies. We pooled dichotomous outcomes (e.g. incidence/recurrence rate of urinary stones; adverse events) using risk ratios (RRs) with 95% confidence intervals (CIs). We calculated hazard ratio (HRs) and corresponding 95% CIs to assess the intervention effect for time-to-event outcomes. We assessed the certainty of the evidence by using the GRADE criteria.

MAIN RESULTS

Our search identified no RCTs investigating the role of increased water intake for the prevention of urinary stone formation in participants with no history of urinary stones (primary prevention). We found one RCT assessing the effects of increased water intake versus standard water intake for the prevention of urinary stone formation in people with a history of urinary stones (secondary prevention). This trial randomised 220 participants (110 participants in the intervention group with increased water intake and 110 in the control group with standard water intake). Increased water intake was defined as achieving a urine volume of at least 2.0 L per day by drinking water. Based on this study, increased water intake may decrease stone recurrences (RR 0.45, 95% CI 0.24 to 0.84; 199 participants; low-certainty evidence); this corresponds to 149 fewer (43 fewer to 205 fewer) stone recurrences per 1000 participants with 270 stone recurrence per 1000 participants over five years in the control group. Increased water intake may also prolong the time to urinary stone recurrence compared to standard water intake (HR 0.40, 95% CI 0.20 to 0.79; 199 participants; low-certainty evidence); based on a stone recurrence rate of 270 per 1000 participants over five years, this corresponds to 152 fewer (209 fewer to 50 fewer) recurrences per 1000 participants. For both outcomes we downgraded the certainty of evidence for study limitations and imprecision. We found no evidence for the outcome of adverse events AUTHORS' CONCLUSIONS: We found no RCT evidence on the role of increased water intake for primary prevention of urinary stones. For secondary prevention, increased water intake achieving a urine volume of at least 2.0 L/day may reduce urinary stone recurrence and prolong time to recurrence for people with a history of urinary stone disease. However, our confidence in these findings is limited. We did not find evidence for adverse events.

Association of Patient and Visit Characteristics With Rate and Timing of Urologic Procedures for Patients Discharged From the Emergency Department With Renal Colic

IMPORTANCE

Little is known about the timing of urologic interventions in patients with renal colic discharged from the emergency department. Understanding patients' likelihood of a subsequent urologic intervention could inform decision-making in this population.

OBJECTIVES

To examine the rate and timing of urologic procedures performed after an emergency department visit for renal colic and the factors associated with receipt of an intervention.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used the Massachusetts All Payers Claims Database to identify patients 18 to 64 years of age who were seen in a Massachusetts emergency department for renal colic from January 1, 2011, to October 31, 2014, Patients were identified via International Classification of Diseases, Ninth Revision codes, and all medical care was linked, enabling identification of subsequent health care use. Data analysis was performed from January 1, 2017, to December 31, 2018.

MAIN OUTCOMES AND MEASURES

The main outcome was receipt of urologic procedure within 60 days. Secondary outcomes included rates of return emergency department visit and urologic and primary care follow-up.

RESULTS

A total of 66 218 unique index visits by 55 314 patients (mean [SD] age, 42.6 [12.4] years; 33 590 [50.7%] female; 25 411 [38.4%] Medicaid insured) were included in the study. A total of 5851 patients (8.8%) had visits resulting in admission at the index encounter, and 1774 (2.7%) had visits resulting in a urologic procedure during that admission. Of the 60 367 patient visits resulting in discharge from the emergency department, 3018 (5.0%) led to a urologic procedure within 7 days, 4407 (7.3%) within 14 days, 5916 (9.8%) within 28 days, and 7667 (12.7%) within 60 days. A total of 3226 visits (5.3%) led to a subsequent emergency department visit within 7 days and 6792 (11.3%) within 60 days. For the entire cohort (admitted and discharged patients), 39 189 (59.2%) had contact with a urologist or primary care practitioner within 60 days. Having Medicaid-only insurance was associated with lower rates of urologic procedures (odds ratio, 0.70; 95% CI, 0.66-0.74) and urologic follow-up (5.6% vs 8.8%; P < .001) and higher rates of primary care follow-up (59.2% vs 47.2%; P < .001) compared with patients with all other insurance types.

CONCLUSIONS AND RELEVANCE

In this cohort study, most adult patients younger than 65 years who were discharged from the emergency department with a diagnosis of renal colic did not undergo a procedure or see a urologist within 60 days. This finding has implications for both the emergency department and outpatient treatment of these patients.

Accuracy of Patient Reported Stone Passage for Patients With Acute Renal Colic Treated in the Emergency Department

OBJECTIVE

To study patients who initially presented to the Emergency Department with acute renal colic to determine if patient-reported stone passage detects stone expulsion as accurately as follow-up computed tomography (CT) scan.

METHODS

This is a secondary analysis of a multi-center prospective trial of patients diagnosed by a CT scan with a symptomatic ureteral stone <9 mm in diameter. Patient-reported stone passage, defined as capture or visualization of the stone, was compared to CT scan-confirmed passage performed 29-36 days after initial presentation.

RESULTS

Four-hundred-three patients were randomized in the original study and 21 were excluded from this analysis because they were lost to follow-up or received ureteroscopic surgery. Of the 382 remaining evaluable patients, 237 (62.0%) underwent a follow-up CT scan. The mean (standard deviation) diameter of the symptomatic kidney stone was 3.8 mm (1.4). In those who reported stone passage, 93.8% (91/97) demonstrated passage of the symptomatic ureteral stone on follow-up CT. Of patients who did not report stone passage, 72.1% (101/140) demonstrated passage of their stone on follow-up CT.

CONCLUSIONS

For patients who report capture or visualization of a ureteral stone, a follow-up CT scan may not be needed to verify stone passage. For patients who do not capture their stone or visualize stone passage, imaging should be considered to confirm passage.