Clinical characteristics of ureteral calculi detected by nonenhanced computerized tomography after unclear results of plain radiography and ultrasonography

Construction of a novel rabbit model of ureteral calculi implanted with flowable resin

BACKGROUND

The purpose of this study was to characterize the pathophysiological changes of hydronephrosis caused by ureteral calculi obstruction in a new rabbit ureteral calculi model by implanting flowable resin.

METHODS

Forty New Zealand rabbits were randomly divided into two groups: the calculi group and the sham control group. In the calculi group (n = 20), rabbits were operated at left lower abdomen and the left ureter was exposed. Then flowable resin (flowable restorative dental materials) was injected into the left ureter using a 0.45 mm diameter intravenous infusion needle. Then light-cured for 40 s by means of a dental curing light to form calculi. In the sham control group, normal saline was injected into the ureter. Rabbits underwent X-ray and routine blood and urine tests preoperatively, as well as X-ray, CT, dissection, HE staining and routine blood and urine tests on 1, 3, 5 and 7 days postoperatively. Stone formation was assessed by X-ray and unenhanced CT scan after surgery. The pathophysiological changes were evaluated through dissection, HE staining and routine blood and urine tests.

RESULTS

Ureteral calculi models were successfully constructed in 17 rabbits. In calculi group, high-density shadows were observed in the left lower abdomen on postoperative day 1st, 3rd, 5th and 7th by X-ray and CT scan. Dissection found obstruction formation of the left ureters, dilatation of the renal pelvis and upper ureter during 7 days after surgery. The renal long-diameters of the left ureters increased only on the 1st postoperative day. HE staining found ureteral and kidney damage after surgery. In calculi group and sham group,the serum creatinine, urea nitrogen, white blood cells and urine red blood cells were raised at day 1 after surgery. However, the indicators returned to normal at day 3, 5, and 7.

CONCLUSIONS

This is a stable, less complicated operation and cost-effective ureteral calculi model by implanting flowable resin. And this novel model may allow us to further understand the pathophysiology changes caused by ureteral calculi obstruction.

Relationship between microscopic haematuria and hydronephrosis in urolithiasis

AIM

The aim of this study was to investigate the relationship between the degree of hydronephrosis and the presence of microscopic haematuria in patients who presented to the emergency department (ED) with ureteral stones.

METHODS

The records of patients who presented to our ED due to urolithiasis between January 2017 and December 2020 were retrospectively analysed. Patients aged 18 years or older who underwent non-contrast computed tomography (CT abdomen/pelvis) and urinalysis (UA) and were diagnosed with ureteral stones were included in the study. Radiology reports were reviewed for stone size, localisation and degree of hydronephrosis. Patients with and without microscopic haematuria and the degree of hydronephrosis were compared.

RESULTS

A total of 476 patients were included, which consisted of 391 with microscopic haematuria and 85 without microscopic haematuria. The median stone size was 4.1 mm in the presence of microscopic haematuria and 5.5 mm in the absence of microscopic haematuria. Logistic regression analysis was performed to determine the factors associated with the development of hydronephrosis. Stone size [odds ratio (OR):2.15, 95% confidence interval (CI):1.12-4.16, P < .001), presence of pyuria (OR: 2.58, 95% CI: 1.78-3.48, P < .001) and absence of microscopic haematuria (OR: 1.31, 95% CI 1.04-2.89, P = .017) were identified as risk factors for moderate and severe hydronephrosis.

CONCLUSION

We consider that imaging studies may be necessary for the diagnosis, and treatment of emergency cases in which microscopic haematuria is not detected in urinalysis since their stone size may be larger and degree of hydronephrosis may be more severe.

Assessment of factors affecting the spontaneous passage of lower ureteric calculus on the basis of lower ureteric calculus diameter, density, and plasma C- reactive protein level

Introduction:

The study aimed to evaluate the factors which affect the spontaneous passage of lower ureteric calculus on the basis of noncontrast computed tomography kidneys, ureters, and bladder (NCCT KUB) stone diameter, stone density, and plasma C-reactive protein (CRP) level.

Materials and Methods:

We conducted a prospective study of 200 patients with lower ureteric calculus 5–10 mm in size, from October 2015 to December 2016. All patients underwent NCCT KUB region with a 5 mm axial and reformatted coronal section. Edema just above the calculus and rim sign at the level of calculus and density of calculus is evaluated. Only scan with isolated, unilateral, solitary ureteric calculus was included in the final analysis and monitored up to 4 weeks, and plasma CRP is estimated in all patients to determine the clinical outcome.

Results:

A total of 200 patients (145 males, 55 females; mean age ± standard deviation, 34.73 ± 10.29) were included in the study. Lower ureteric calculus between 5–7 mm passed in 70% and 7–10 mm passed in 40%. There was 18% underestimation of maximum stone diameter in axial plane as compared to coronal plane. For spontaneous passage of calculus, craniocaudal (CC) diameter is more reliable then axial in NCCT. Rim sign and edema is absent in 64% of those passed spontaneous calculus. CRP level more than 2.45 mg/dl has low spontaneous expulsion rate. The stone with different HU passes through the ureter with same rate.

Conclusion:

Plasma CRP level and CC diameter and absence of rim sign on NCCT KUB are more reliable factors then density for spontaneous passage of ureteric calculus.

The utility of renal ultrasonography in the diagnosis of renal colic in emergency department patients

Objective:

Computed tomography (CT) is an imaging modality used to detect renal stones. However, there is concern about the lifetime cumulative radiation exposure attributed to CT. Ultrasonography (US) has been used to diagnose urolithiasis, thereby avoiding radiation exposure. The objective of this study was to determine the ability of US to identify renal colic patients with a low risk of requiring urologic intervention within 90 days of their initial emergency department (ED) visit.

Methods:

We completed a retrospective medical record review for all adult patients who underwent ED-ordered renal US for suspected urolithiasis over a 1-year period. Independent, double data extraction was performed for all imaging reports and US results were categorized as “normal,” “suggestive of ureterolithiasis,” “ureteric stone seen” or “disease unrelated to urolithiasis.” Charts were reviewed to determine how many patients underwent subsequent CT and urologic intervention.

Results:

Of the 817 renal US procedures ordered for suspected urolithiasis during the study period, the results of 352 (43.2%) were classified as normal, and only 2 (0.6%) of these patients required urologic intervention. The results of 177 (21.7%) renal US procedures were suggestive of ureterolithiasis. Of these, 12 (6.8%) patients required urologic intervention. Of the 241 (29.5%) patients who had a ureteric stone seen on US, 15 (6.2%) required urologic intervention. The rate of urologic intervention was significantly lower in those with normal results on US (p &lt; 0.001) than in those with abnormal results on US.

Conclusion:

A normal result on renal US predicts a low likelihood for urologic intervention within 90 days for adult ED patients with suspected urolithiasis.

Is pre-operative imaging essential prior to ureteric stone surgery?

INTRODUCTION

The aim of this study was to identify patients not requiring ureteric stone surgery based on pre-operative imaging (within 24 hours) prior to embarking on semirigid ureteroscopy (R-URS) for urolithiasis.

METHODS

The imaging of all consecutive patients on whom R-URS for urolithiasis was performed over a 12-month period was reviewed. All patients had undergone a plain x-ray of the kidney, ureters and bladder (KUB), abdominal non-contrast computed tomography (NCCT-KUB) or both on the day of surgery.

RESULTS

A total of 96 patients were identified for the study. Stone sizes ranged from 3mm to 20mm. Thirteen patients (14%) were cancelled as no stone(s) were identified on pre-operative imaging. Of the patients cancelled, 8 (62%) required NCCT-KUB to confirm spontaneous stone passage.

CONCLUSIONS

One in seven patients were stone free on the day of surgery. This negates the need for unnecessary anaesthetic and instrumentation of the urinary tract, with the associated morbidity. Up-to-date imaging prior to embarking on elective ureteric stone surgery is highly recommended.

Expectant Management of Ureter Stones: Outcome and Clinical Factors of Spontaneous Passage in a Single Institution's Experience

Purpose

The aim of this study was to evaluate the outcome of ureter stones with expectant management and the clinical factors associated with stone passage in Koreans.

Materials and Methods

We reviewed the charts of patients who visited the emergency room or urological office of our institution with acute renal colic between 2001 and 2008. A total of 656 ureter stone formers were enrolled in this study who had decided to be treated by expectant management. Clinical data such as gender, age, size and location of the stone, body mass index, and previous stone history were analyzed to find the factors related to spontaneous passage of ureter stones.

Results

Of the 656 ureter stones, 566 stones (86.3%) were spontaneously expelled. Mean duration of follow-up was 17.5 days (range, 1 to 100 days). Mean time to stone passage was 6.8 days for stones less than 2 mm in size, 12.6 days for stones 2 to 4 mm, 14.8 days for stones 4 to 6 mm, and 21.8 days for stones 6 to 8 mm (p<0.001). The cumulative spontaneous passage rate was 55.3% in 7 days, 73.7% in 14 days, 88.5% in 28 days, and 97.7% in 60 days after the first attack. A total of 90 patients (13.7%) required interventions because of symptom relapse or renal deterioration that was related to the location and size of the stone (each, p<0.001). The more proximal the location and the larger the stone was than 6 mm, the less the chance of spontaneous passage (each, p<0.001).

Conclusions

Size and location of ureter stones are the most important factors for predicting the spontaneous passage of the stone. If a patient has a distal ureter stone of less than 6 mm in size, it is acceptable for the urologist to observe for spontaneous passage for 2 months.

Predicting intervention in renal colic patients after emergency department evaluation

OBJECTIVES

There is no set of prospectively validated criteria to identify the emergency department (ED) patients with renal colic who are most likely to eventually have to undergo an intervention. This study prospectively assessed predictors of intervention in this patient population.

METHODS

This prospective cohort study included adult patients with renal colic who presented to 2 tertiary care hospital EDs. Patients had an 18-variable data form completed by an emergency physician and a radiological study to confirm urolithiasis. After discharge, patients were followed at 1 and 4 weeks to assess for intervention. The outcome criteria included the patient having had at least 1 of the following procedures performed: extracorporeal shockwave lithotripsy (ESWL), ureteroscopy, percutaneous nephrostomy or open surgery. Data were analyzed using appropriate univariate techniques, and those variables associated with intervention were combined using logistic regression analysis.

RESULTS

Over an 8-month period, 245 patients with confirmed urolithiasis were followed; 20% (95% confidence interval [CI] 15%-25%) eventually had a procedure to remove their calculi. Three variables were significantly correlated with having a procedure: i) size of calculus >or= 6 mm (odds ratio [OR] 10.7, 95% CI 4.6-24.8), ii) location of calculus above mid-ureter (OR 6.9, 95% CI 3.0-15.9), and iii) Visual Analogue Scale score for pain at discharge from the ED >or= 2 cm (OR 2.6, 95% CI 1.0-6.8). The area under receiver operating characteristic curve was 0.77 (95% C I 0.70-0.84) (p < 0.001). If all variables were present there was a 90% probability of the patient having an intervention performed within 4 weeks of discharge from the ED. Conversely, if none of the variables were present there was only a 4% probability of an intervention. Overall, the model had a sensitivity of 92% (95% CI 89%-96%) and a specificity of 63% (95% CI 57%-69%).

CONCLUSIONS

This study has identified variables that could potentially be used to identify those renal colic patients who require an intervention after ED evaluation. Future studies will prospectively validate this model.

[Diagnosis and therapy of acute ureteral colic]

Acute ureteral colic presents with a complex of acute and characteristic flank pain that usually indicates the presence of a stone in the urinary tract. Diagnosis and management of renal colic have undergone considerable evolution and advancement in recent years. The application of noncontrast helical computed tomography (CT) in patients with suspected ureteral colic is one major advance in the primary diagnostic process. The superior sensitivity and specificity of helical CT allow ureterolithiasis to be diagnosed without the potential side effects of contrast media. Initial management is based on three key concepts: (A) rational and fast diagnostic process (B) effective pain control (C) and understanding of the impact of stone location and size on the natural course of the disease and definitive urologic management. These concepts are discussed in this review with reference to contemporary literature.

Low-dose versus standard-dose CT protocol in patients with clinically suspected renal colic

OBJECTIVE

The purpose of our study was to compare a low-dose abdominal CT protocol, delivering a dose of radiation close to the dose delivered by abdominal radiography, with standard-dose unenhanced CT in patients with suspected renal colic.

MATERIALS AND METHODS

One hundred twenty-five patients (87 men, 38 women; mean age, 45 years) who were admitted with suspected renal colic underwent both abdominal low-dose CT (30 mAs) and standard-dose CT (180 mAs). Low-dose CT and standard-dose CT were independently reviewed, in a delayed fashion, by two radiologists for the characterization of renal and ureteral calculi (location, size) and for indirect signs of renal colic (renal enlargement, pyeloureteral dilatation, periureteral or renal stranding). Results reported for low-dose CT, with regard to the patients' body mass indexes (BMIs), were compared with those obtained with standard-dose CT (reference standard). The presence of non-urinary tract-related disorders was also assessed. Informed consent was obtained from all patients.

RESULTS

In patients with a BMI < 30, low-dose CT achieved 96% sensitivity and 100% specificity for the detection of indirect signs of renal colic and a sensitivity of 95% and a specificity of 97% for detecting ureteral calculi. In patients with a BMI < 30, low-dose CT was 86% sensitive for detecting ureteral calculi < 3 mm and 100% sensitive for detecting calculi > 3 mm. Low-dose CT was 100% sensitive and specific for depicting non-urinary tract-related disorders (n = 6).

CONCLUSION

Low-dose CT achieves sensitivities and specificities close to those of standard-dose CT in assessing the diagnosis of renal colic, depicting ureteral calculi > 3 mm in patients with a BMI < 30, and correctly identifying alternative diagnoses.