Does the presence of non-refluxing hydroureter impact the management and outcome of high-grade hydronephrosis?

INTRODUCTION: We aimed to evaluate the impact of non-refluxing hydroureter on the initial management of high-grade hydronephrosis (HGH) management. Moreover, we evaluated the occurrence of febrile urinary tract infection (fUTI) and surgical intervention for conservatively managed units. METHODS: Patients' charts with postnatal hydronephrosis from 2008-2014 were retrospectively reviewed. We included patients who presented in the first year of life. All included patients had HGH (Society of Fetal Ultrasound [SFU] grades 3 and 4) and all were non-refluxing using voiding cystourethrogram (VCUG). We categorized renal units into two groups: with hydroureteronephrosis (HUN) and without hydroureter (isolated hydronephrosis [IH]). We recorded the initial management. We evaluated the impact of non-refluxing hydroureter on hydronephrosis fate, fUTI, and change to surgery for those managed conservatively. RESULTS: We included 169 patients (180 units). IH was diagnosed in 146 units (137 patients), whereas 34 units (32 patients) had HUN. Median followup was 42.9 months. A total of 25.3% (37/146) of IH units had initial surgical management in comparison to 5.1% (2/34) of HUN units (p=0.01). During conservative management, nine HUN patients (30%) and 11 IH patients (10.7%) experienced fUTI (p=0.009). Surgical intervention after failed conservative management was indicated for 12 IH units (11%) and six HUN units (18.8%) (p=0.25). Anteroposterior diameter (APD) worsening was significantly associated with the change to surgery in IH group (p=0.003). More than half (52.3%) of IH units resolved during conservative management in comparison to 18.7% of HUN (p<0.001). HUN had longer time to resolution (log rank=0.004). CONCLUSIONS: IH units had more initial surgical interventions. The fUTI rate was much higher in association with dilated ureter even under antibiotic coverage. HUN was associated with less and slower resolution rate.

Influence of postnatal hydroureter in determining the need for voiding cystourethrogram in children with high-grade hydronephrosis.

OBJECTIVE: To evaluate the utility of hydroureter (HU) to identify high-grade vesico-ureteric reflux (VUR) in patients with high-grade postnatal hydronephrosis (PH). PATIENTS AND METHODS: We retrospectively reviewed patients' charts that had antenatal hydronephrosis from 2008 to 2014. Patients were excluded if they presented with febrile urinary tract infection (fUTI), neurogenic bladder, posterior urethral valve, multi-cystic dysplastic kidney, and multiple congenital malformations. We reviewed postnatal ultrasonography images and patients with Society of Fetal Urology (SFU) Grades 3 and 4 hydronephrosis with a renal pelvic antero-posterior diameter of ≥10 mm were included. The ureter was assessed and considered dilated if the ureteric diameter was  ≥4 mm. The voiding cystourethrogram (VCUG) studies, fUTI incidence, and surgical reports were reviewed. RESULTS: Of the 654 patients reviewed, we included 148 patients (164 renal units) of whom 113 (76.4%) were male and 35 (23.6%) female. SFU Grade 3 PH was identified in 49% of the renal units, with the remaining 51% being SFU Grade 4. HU was found in 50/164 renal units and was not detected in the remaining 114 units. VUR was diagnosed in four units (3.5%) without HU (low-grade VUR); whilst it was detected in 19 units (38%) with HU (72.7% were high-grade VUR) (P < 0.001). VUR was diagnosed on the contralateral side in four/105 patients with PH without HU and diagnosed in 10/43 patients with PH with HU (P < 0.001). During a median follow-up of 25.9 months, none of the renal units that had VUR without HU developed UTI or had surgeries. CONCLUSION: Low-grade uncomplicated VUR was diagnosed in 3.5% of renal units without HU. Our results support limiting the use of VCUG to renal units with PH if associated with HU.

Is the renal pyramidal thickness a good predictor for pyeloplasty in postnatal hydronephrosis?

OBJECTIVES: We evaluated the feasibility and value of renal pyramidal thickness (PT) as a predictor of pyeloplasty in high-grade postnatal hydronephrosis. PATIENTS AND METHODS: We retrospectively reviewed the charts of patients who presented with postnatal hydronephrosis from 2008 to 2013. Included cases had grade 3 or 4 hydronephrosis. We included only units diagnosed as ureteropelvic junction obstruction. Gender, laterality, hydronephrosis side, renogram data, and follow-up data were recorded. Two investigators reviewed all patients' ultrasounds images. We measured PT and pelvic anteroposterior diameter (APD) in the last ultrasound before surgery. For those managed conservatively, measurements were obtained from the ultrasound with worst hydronephrosis. PT was measured in supine position in the middle third of the sagittal plane (Figure). We assessed the reliability of PT measurement using the intraclass correlation coefficient (ICC). Univariate and multivariate analyses were used to correlate the collected parameters to pyeloplasty incidence. Receiver operating characteristic curve was used to evaluate the cutoff value of PT that predicts pyeloplasty. RESULTS: The total included cases were 155 patients (165 units). One hundred and fourteen units had grade 3 hydronephrosis and 51 units had grade 4 hydronephrosis. Fifty-two cases (55 units) underwent pyeloplasty. The median follow-up period was 37.6 months. PT measurement was reliable (ICC = 0.94). Univariate analysis revealed that SFU grading, APD, PT, T1/2, and MAG-3 curves were associated with surgery. Multivariate analysis showed that PT was a single independent predictor for pyeloplasty. PT ≤ 3 mm had 98.1% sensitivity and 89.7% specificity in predicting pyeloplasty. DISCUSSION: PT is the first portion of renal parenchyma that is affected in high-grade hydronephrosis. Moreover, it changes little over the first 9 years of life. PT measurement in hydronephrosis was not previously evaluated. We found that PT was easily measured in most kidneys with high negative predictive value. The PT value as an indicator for pyeloplasty should undergo extensive assessment by other institutions with different protocols. CONCLUSION: Being a slowly growing part of the parenchyma, PT can be a good measurable parameter to predict pyeloplasty. Measurement of PT in hydronephrosis is reliable. PT ≤ 3 mm can predict pyeloplasty with 98.1% sensitivity and 89.7% specificity.

Evaluation of Urinary Tract Dilation Classification System for Grading Postnatal Hydronephrosis.

PURPOSE: We assessed the reliability and validity of the Urinary Tract Dilation classification system as a new grading system for postnatal hydronephrosis. MATERIALS AND METHODS: We retrospectively reviewed charts of patients who presented with hydronephrosis from 2008 to 2013. We included patients diagnosed prenatally and those with hydronephrosis discovered incidentally during the first year of life. We excluded cases involving urinary tract infection, neurogenic bladder and chromosomal anomalies, those associated with extraurinary congenital malformations and those with followup of less than 24 months without resolution. Hydronephrosis was graded postnatally using the Society for Fetal Urology system, and then the management protocol was chosen. All units were regraded using the Urinary Tract Dilation classification system and compared to the Society for Fetal Urology system to assess reliability. Univariate and multivariate analyses were performed to assess the validity of the Urinary Tract Dilation classification system in predicting hydronephrosis resolution and surgical intervention. RESULTS: A total of 490 patients (730 renal units) were eligible to participate. The Urinary Tract Dilation classification system was reliable in the assessment of hydronephrosis (parallel forms 0.92). Hydronephrosis resolved in 357 units (49%), and 86 units (12%) were managed by surgical intervention. The remainder of renal units demonstrated stable or improved hydronephrosis. Multivariate analysis revealed that the likelihood of surgical intervention was predicted independently by Urinary Tract Dilation classification system risk group, while Society for Fetal Urology grades were predictive of likelihood of resolution. CONCLUSIONS: The Urinary Tract Dilation classification system is reliable for evaluation of postnatal hydronephrosis and is valid in predicting surgical intervention.