Diagnostic accuracy of Onen's Alternative Grading System combined with Doppler evaluation of ureteral jets as an alternative in the diagnosis of obstructive hydronephrosis in children

Combination of robot-assisted laparoscopy and ureteroscopy for the management of complex ureteral strictures

BACKGROUND

To summarize the efficacy of combined robot-assisted laparoscopy and ureteroscopy in treating complex ureteral strictures.

METHODS

Eleven patients underwent combined robot-assisted laparoscopy and ureteroscopy for ureteral strictures between January 2020 and August 2022. Preoperative B-ultrasound, glomerular filtration rate measurement, and intravenous pyelography showed different degrees of hydronephrosis in the affected kidney and moderate to severe stenosis in the corresponding part of the ureter. During the operation, stricture segment resection and end-to-end anastomosis were performed using the da Vinci robot to find the stricture point under the guidance of a ureteroscopic light source in the lateral or supine lithotomy position.

RESULTS

All the patients underwent robot-assisted laparoscopy and ureteroscopy combined with end-to-end ureterostenosis. There were no conversions to open surgery or intraoperative complications. Significant ureteral stricture segments were found in all patients intraoperatively; however, stricture length was not significantly different from the imaging findings. Patients were followed up for 3-27 months. Two months postoperatively, the double-J stent was removed, a ureteroscopy was performed, the ureteral mucosa at the end-to-end anastomosis grew well, and the lumen was patent in all patients. Furthermore, imaging examination showed that hydronephrosis was significantly improved in all patients, with grade I hydronephrosis in three cases and grade 0 hydronephrosis in eight cases. No recurrence of ureteral stricture was observed in patients followed up for > 1 year.

CONCLUSION

Robot-assisted laparoscopy combined with ureteroscopy is an effective method for treating complex ureteral strictures and can achieve accurate localization of the structured segment.

Color Doppler Ultrasound's Utility in Detecting Vesicoureteral Reflux Using the Ureteral Jet Angle

OBJECTIVES

This study hypothesizes using color Doppler ultrasound to measure ureteral jet angles (UJA) as a diagnostic screening tool for reflux.

METHODS

The present prospective cohort study included 122 patients and 238 renal unit pediatric patients suspected of VUR who presented to our hospital between 2019 and 2021. All patients underwent ultrasonography and VCUG, and the UJA was measured color Doppler evaluation of the ureteral jet. The UJA was compared with the VCUG findings in patients with and without reflux. SPSS 26 was used to analyze the data.

RESULTS

A total of 96 patients and 139 renal units exhibited reflux. The mean ureteral jet angle in refluxing units was 60.47 + 16.66 degrees, whereas, it was 42.59 + 13.26 degrees in non-refluxing units, a significant difference between the two groups (P < .001). The mean ureteral jet angle was 42.59, 45.89, 60.32, 68.23, and 56.16, for reflux grading from 0 to 5 (except grade 1), respectively. The angle value in each reflux grade increased significantly except for grade 5. For reflux detection (grade I-V), a cut-off angle of 50 degrees was associated with sensitivity and specificity of 70 and 79, respectively. Grade IV/V reflux can be diagnosed with a sensitivity of 70% and specificity of 84% using a cut-off angle of 68 degrees or greater.

CONCLUSIONS

UJA detection via color Doppler ultrasound demonstrates high accuracy, is non-invasive method can be utilized as an alternative primary diagnostic tool or in follow-up cases of VUR in children.

Urine Biomarkers Combined With Ultrasound for the Diagnosis of Obstruction in Pediatric Hydronephrosis

Introduction: To establish the efficacy of ultrasound (US) combined with urine biomarkers in differentiating patients who require surgical management from those who do not, avoiding invasive investigations. Materials and Methods: From February 2019 to February 2021, all pediatric patients who presented with hydronephrosis were selected for the study. All renal units (RU) were evaluated by US, and fresh frozen voided urine samples were collected at the time of inclusion. Hydronephrosis grade was evaluated by the Society for Fetal Urology (SFU) and an alternative grading system (AGS). Patients who had high-grade hydronephrosis on US were referred to renal scan (RS) or intervention, when there was an increase of dilatation in subsequent follow-up images. Fresh frozen urine from the control group with no history of renal diseases and no renal anomalies on US was collected. We compared differences of US parameters combined with urine biomarkers between surgically and non-surgically managed patients and between the groups of patients when they were stratified by different RS findings and analyzed whether urinary biomarkers give any additional value to US. Instead of the anterior-posterior diameter (APD), we used its ratio with mid-parenchymal thickness. The additional efficacy of biomarkers to US was calculated when the US component was derived to a cumulative APD/mid-parenchymal ratio. Results: Sixty-four patients with hydronephrosis were prospectively included in the study accounting for a total of 81 patient visits and 162 RUs evaluated. A control group of 26 patients was collected. The mean age at inclusion in the hydronephrosis group was 43.7(±45.5) months, and a mean age in a control group was 61.2(±41.3) months. The cumulative APD/mid-parenchymal ratio combined with urinary albumin, β2 microglobulin (β2-M), and urinary neutrophil gelatinase-associated lipocalcin may have a better performance in the prediction of surgical intervention than the cumulative APD/mid-parenchymal ratio alone (p = 0.1). The best performance to detect the increased tissue transit time and obstructive curve on RS was demonstrated by the β2-M creatinine ratio. An increased cumulative APD/mid-parenchymal ratio with biomarkers together had a fairly good sensitivity and specificity for detection of DRF < 40%. Conclusions: According to our data, the APD/mid-parenchymal ratio alone has good efficacy in prediction of surgery and abnormal RS findings especially when combined with urine biomarkers.

The different elements of the Urinary Tract Dilation (UTD) Classification System and their capacity to predict findings on mercaptoacetyltriglycine (MAG3) diuretic renography

INTRODUCTION

The UTD Classification System risk stratifies postnatal UTD into three groups: low risk (UTD P1), intermediate risk (UTD P2), and high risk (UTD P3). In the original consensus document, a functional scan is not recommended for UTD P1 and is left to the discretion of the clinician for UTD P2 and P3.

OBJECTIVE

This study aims to understand which patients with postnatal urinary tract dilation would benefit from a functional study. We investigated how different elements of the UTD classification system predict differential renal function (DRF) and diuretic half-life (T½) on MAG3 scan in infants undergoing evaluation for prenatally detected UTD.

STUDY DESIGN

This is a multicenter retrospective chart review of infants 6 months of age or younger evaluated for prenatal UTD, correlating their first MAG3 scan and first postnatal renal ultrasound (RUS). Multivariable logistic regression was used to find UTD elements predictive of DRF < 40% and/or T½ > 20 min.

RESULTS

A total of 517 patients met study criteria. Median age at time of RUS and MAG3 renal scan was 48 days (IGR 31-81) and 63 days (IQR 45-98), respectively. DRF < 40% was found in 6% of kidneys with UTD P2 and 35% of kidneys with UTD P3. T½ > 20 min was found in 31% of kidneys with UTD P2 and 79% of kidneys with UTD P3. An abnormal ureter (OR 2.7, 95% CI 1.2-6.0) and parenchymal thinning (OR 16, 95% CI 5.8-41.4) were significant at predicting DRF < 40%. Parenchymal thinning (OR 3.0, 95% CI 1.5-6.1) also predicted T½ > 20 min, as did each cm increase in the anterior-posterior renal pelvic diameter (APRPD) (OR 4.8, 95% CI 3.0-7.7).

DISCUSSION

The UTD system discriminates well and correlates with the likelihood of finding adverse features on diuretic renography. Patients in the UTD P3 high-risk category had a significantly higher incidence of decreased differential renal function and delayed drainage than those in UTD P1 and P2. Of the individual components of the UTD Classification system, the presence of parenchymal thinning was the most important factor in predicting both decreased differential renal function and delayed drainage.

CONCLUSION

Given the high incidence of poor function and delayed drainage seen in the UTD P3 group, we believe a functional study should be recommended in the evaluation of these patients. Our findings support leaving the performance of a functional study at the discretion of the physician for UTD P2.

Grading of Hydronephrosis: An Ongoing Challenge

The crucial point for prompt diagnostics, ideal therapeutic approach, and follow-up of hydronephrosis associated with UPJ anomalies in children is the severity of hydronephrosis. Such many hydronephrosis grading systems as AP diameter, SFU, radiology, UTD, and Onen have been developed to evaluate hydronephrosis severity in infants. Unfortunately, it is still an ongoing challenge and there is no consensus between different disciplines. AP diameter is a very dynamic parameter and is affected by many factors (hydration, bladder filling, position, respiration). More importantly, its measurement is very variable and misleading due to different renal pelvic configurations. The radiology grading system has the same grades 1, 2, and 3 as the SFU grading system with addition of the AP diameter for the first 3 grades. This grading system divides parenchymal loss into two different grades. Grade 4 represents mild parenchymal loss while grade 5 suggests severe parenchymal loss. However, it is operator dependent, is not decisive, and does not differentiate grades 4 and 5 clearly. All grades of SFU are very variable between operators and clinicians. UTD classification aims to put all significant abnormal urinary findings together including the kidney, ureter, and bladder and thus determines the risk level for infants with any urinary disease. Different renal deterioration risks occur depending on the mechanism of hydronephrosis. Therefore, SFU and UTD classification may result in significant confusion and misleading in determining the severity of hydronephrosis. SFU-4 and UTD-P3 represent a considerable range of severity of hydronephrosis. Both represent minimal thinning of the medullary parenchyma and severe thinning of the cortical parenchyma (cyst-like hydronephrotic kidneys) at the same grade. The wide definition of SFU-4 and UTD-P3 fails to indicate accurately the severity of hydronephrosis and thus significantly misleads from a prompt treatment. They do not suggest who need surgical treatment and who can safely be followed non-operatively. The anatomy and physiology of the 4 suborgans of the kidney (renal pelvis, calices, medulla, and cortex) are completely different from each other. Therefore, each part of the kidney affect and behave differently as a response to UPJ-type hydronephrosis (UPJHN) depending on the severity of hydronephrosis. The upgraded Onen hydronephrosis grading system has been developed based on this basic evidence both for prenatal and post-natal periods. The Onen grading system determines specific detailed findings of significant renal damage, which clearly show and suggest who can safely be followed conservatively from who will need surgical intervention for UPJHN. Neither AP diameter nor radiology, SFU, or UTD classification is the gold standard in determining the severity of hydronephrosis. All these grading systems are based on subjective parameters and are affected by many factors. They do not determine the exact severity of UPJHN and thus cause permanent renal damage due to a delay in surgical decision in some infants while they may cause an unnecessary surgery in others. The Onen grading system has resolved all disadvantages of other grading systems and promises a safer follow-up and a prompt treatment for UPJHN. It is an accurate and easily reproducible grading that has high sensitivity and specificity.

Diuretic Enhanced Ultrasonography in the Diagnosis of Pyeloureteral Obstruction

Background and Objectives: To determine the value of diuretic ultrasonography for the diagnosis of obstructive hydronephrosis. Materials and Methods: Diuretic enhanced ultrasonography was used routinely as a part of examination of patients with hydronephrosis in our Department. There were 72 patients (42 males, 30 females; aged 2 months to 17 years; median age 7.07 years) with a sonoscopic diagnosis of hydronephrosis included from January 2006 until October 2011. The anteroposterior diameter (AD) of renal pelvis was measured sonoscopically before and at sixty minutes after furosemide injection. A weight-adjusted dose of 1 mg/kg of furosemide was administered intravenously. Results: Patients were operated on if pyeloureteral obstruction was suspected because of low or deteriorating differential renal function, increasing hydronephrosis or symptoms thereof. Hydronephrosis was unilateral in 61 (84.7%) and bilateral in 11 (15.3%) patients. The median AD of pelvis before furosemide injection was 22 mm in operated and 17 mm in non-operated patients (p = 0.005). Sixty minutes after furosemide injection, the AD of pelvis in operated patients was 35.5 mm and 25.8 mm in non-operated—25.8 mm (p < 0.001). Logistic regression model demonstrated that significant factors for surgery were: AD 60 min after furosemide infection and ultrasonographic parenchymal sclerosis. Conclusion: Ultrasound measurement of the AD of renal pelvis 1 h after the injection of furosemide used as an additional investigation can help in predicting obstructive hydronephrosis.