Diagnostic Value of Anteroposterior Diameter of Fetal Renal Pelvis During Second and Third Trimesters in Predicting Postnatal Surgery Among Korean Population: Useful Information for Antenatal Counseling

Postnatal management of children with antenatal hydronephrosis

Background

Postnatal management of infants with antenatal hydronephrosis (ANH) is still one of the most controversial issues. The majority of infants with ANH are asymptomatic with only few children who develop renal insufficiency. Thus, the biggest challenge for pediatric urologists is to distinguish children who will require further investigations and possible intervention prior to the development of symptoms, complications or renal damage in a cost effective manner without exposing them to the hazards of unnecessary investigations.

Main body

In this review article, literature on ANH were reviewed to present the current suggestions, recommendations, guidelines and their rational for postnatal management of ANH. It is agreed that a large portion of infants with ANH will improve; thus, the protocol of management is based mainly on observation and follow-up by ultrasound to detect either resolution, stabilization or worsening of hydronephrosis. The first 2 years of life are critical for this follow-up as the final picture is mostly reached during that period. Advanced imaging using voiding cystourethrography or renal scintigraphy are required for children at risk. Then, surgical intervention is selected only for a subgroup of these infants who showed worsening of hydronephrosis or renal function.

Conclusions

The protocol of management is based mainly on observation and follow-up by US to detect either resolution, stabilization or worsening of hydronephrosis. Postnatal evaluation should be performed for any neonate with a history ANH at any stage during pregnancy even if it was resolved during third trimester. Exclusion of UTI should be performed by urinalysis for all cases followed by urine culture if indicated. Serum creatinine should be performed especially in patients with bilateral ANH. US is the initial standard diagnostic imaging technique. Other imaging modalities like VCUG and nuclear renal scans may be required according to the results of the US evaluation. The most important items in decision making are the presence of bilateral or unilateral hydronephrosis, presence or absence of hydroureter, presence of lower urinary tract obstruction and degree of hydronephrosis on the initial postnatal US. Then an intervention is selected only for a subgroup of these patients who showed deterioration in renal function or degree of hydronephrosis or were complicated by UTIs. All these recommendations are based on the available literature. However, management of ANH is still a controversial issue due to lack of high evidence-based recommendations. Randomised controlled studies are still needed to provide a high level evidence for different aspects of management.

Outcomes of urinary tract abnormalities diagnosed by the routine third trimester scan

OBJECTIVE

The aim of this study is to determine the incidence of congenital abnormalities of the kidneys and urinary tract (CAKUT) detected for the first time in an unselected population undergoing a routine third trimester scan between 30-34 week's gestation.

METHODS

This was a retrospective analysis of 8562 routine third trimester ultrasound scans during which the fetal anatomy was evaluated, and, any structural abnormalities detected, recorded onto a fetal database which was subsequently analysed for CAKUT. All postnatal records of antenatally diagnosed CAKUT were obtained and analysed for diagnosis and management.

RESULTS

There were 26 cases of urological abnormalities detected for the first time in the third trimester. The most frequent abnormality was unilateral renal pelvis dilatation (73%). Postnatal ultrasound confirmed abnormalities in 19 (73%) newborns, with two (8%) resolving antenatally and four (15%) postnatally. The overall incidence of new CAKUT detected by the third trimester scan was 0.22% (19/8562) with a male to female ratio of 1:1.6. Four patients required surgery, two received cystoscopic injection of Deflux with circumcision, one received cystoscopic valve ablation and one patient received a staged hypospadias repair.

CONCLUSION

Routine third trimester scanning is already performed in many countries with proposed benefits primarily directed towards the monitoring of fetal growth and late pregnancy malpresentation. For healthcare systems that still utilize two routine scans, debate is ongoing as to the value of introducing a routine third trimester scan. The ability to detect additional and potentially missed CAKUT is a further benefit, which in isolation is likely of too small an impact to merit implementation. However, the combination of fetal structural assessment, growth velocity monitoring and fetal presentation evaluation presents a strong case for inclusion in an antenatal screening program. The findings of this study highlight the importance of a detailed fetal structural evaluation at each antenatal ultrasound scan.

Value of renal pelvic diameter and urinary tract dilation classification in the prediction of urinary tract anomaly

BACKGROUND

The aim of this study was to identify the cut-offs of postnatal anteroposterior renal pelvic diameter (APRPD), according to the urinary tract dilation (UTD) classification system, to identify the predictors of final diagnosis of UTD and the need for surgery.

METHODS

A total of 260 infants (336 renal units) with prenatally detected UTD were prospectively evaluated on serial ultrasonography by the same radiologist. Additional voiding cystourethrography and scintigraphy was done according to the clinical algorithm.

RESULTS

Prenatal and postnatal APRPD in patients with transient dilation were significantly lower than in those with urinary tract anomalies (UTA). On follow up, the slope of decrease in APRPD was significantly higher in transient dilation compared with UTA. APRPD 10 mm at first-month ultrasonography, predicted UTA with a sensitivity of 83.1%, and specificity of 71.1%. On multivariate analysis the likelihood of surgical intervention and final diagnosis were predicted independently by the UTD system risk group.

CONCLUSIONS

Careful ultrasonography evaluation can avoid unnecessary testing in patients with transient or clinically insignificant dilation. The UTD classification system is valid for evaluation of postnatal hydronephrosis and is reliable in predicting the need for surgical intervention.

Diagnostic Value of Anteroposterior Diameter of Renal Pelvis for Predicting Postnatal Surgery: A Systematic Review and Meta-Analysis

PURPOSE

We assessed the diagnostic value of anteroposterior diameter of the fetal renal pelvis in predicting postnatal surgery.

MATERIALS AND METHODS

PubMed®, Embase® and Cochrane Library databases were searched for articles comparing patients who underwent surgery or conservative therapy with 15 mm anteroposterior diameter as a cutoff value. Data on sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic OR and area under the summary ROC curve were used to evaluate the diagnostic value of anteroposterior diameter of the fetal renal pelvis in predicting postnatal surgery.

RESULTS

Five studies involving a total of 1,159 patients met the inclusion criteria. The summary sensitivity and specificity were 0.81 (95% CI 0.60 to 0.92) and 0.78 (95% CI 0.68 to 0.86), respectively. Positive and negative likelihood ratios of anteroposterior diameter were 3.73 (95% CI 2.75 to 5.06) and 0.24 (95% CI 0.11 to 0.52), respectively. Diagnostic OR of anteroposterior diameter for predicting postnatal surgery was 13.33 (95% CI 6.61 to 26.89) and area under the summary ROC curve was 0.85 (95% CI 0.82 to 0.88). Subgroup analysis suggested postnatal anteroposterior diameter was associated with higher diagnostic OR compared to prenatal anteroposterior diameter for predicting postnatal surgery (ratio between prenatal and postnatal anteroposterior diameter 0.27, 95% CI 0.09 to 0.86, p = 0.026).

CONCLUSIONS

Using 15 mm anteroposterior diameter of the fetal renal pelvis as a cutoff showed moderate diagnostic value for predicting postnatal surgery.

Prenatally detected, unilateral, high-grade hydronephrosis: Can we predict the natural history?

INTRODUCTION

Fetal hydronephrosis (HN) occurs in approximately 5% of pregnancies and its prognosis depends mainly on the grade of the dilation. We attempted to determine the fate of isolated, unilateral, high-grade HN in children with antenatal diagnosis, emphasizing the risk factors for progression.

METHODS

We retrospectively evaluated 424 children (690 kidney units) with antenatal HN in the period between 2010 and 2014. We included only those patients with isolated high-grade HN (Society for Fetal Urology [SFU] Grade 3 or 4). Patients with bilateral HN or unilateral HN associated with dilated ureter or reflux and patients with missed followup were excluded. The prognosis of HN (whether improved, stabilized, or progressed) and the need for surgical intervention in this subset of patients was evaluated.

RESULTS

A total of 44 children (34 boys and 10 girls) were identified. Ultrasounds showed SFU Grade 3 HN in 24 (54%) and SFU Grade 4 HN in 20 (46%). After a mean followup of three years (range 1-5), 10 children (23%) needed surgical intervention; four Grade 3 HN (16%) and six Grade 4 HN (30%). The majority of children with differential renal function (DRF) ≥40% (69.5%) were stable or improved. Five girls (50%) and five boys (17%) progressed and required surgical intervention. No patient with a renal pelvis anteroposterior diameter (APD) <1.5 cm needed surgical intervention.

CONCLUSIONS

Infants with isolated, unilateral, high-grade HN might be managed conservatively. Male gender, DRF ≥40%, SFU Grade 3 HN, and APD <1.5 cm were favourable prognostic factors.

Determination of the Need for Surgical Intervention in Infants Diagnosed with Fetal Hydronephrosis in China

Background

Hydronephrosis is a common congenital condition. The detection of fetal hydronephrosis by ultrasound presents a treatment dilemma. This study aims to examine postnatal follow-up and treatment for hydronephrosis diagnosed prenatally.

Material/Methods

This was a retrospective study of 210 infants with hydronephrosis diagnosed at the Qilu Hospital (Shangdong, China) between January 2005 and January 2013. The patient cohort was divided into four groups based on prenatal ultrasound examinations using the Society for Fetal Urology (SFU) classification system. Data on follow-up investigations and treatment methods were extracted from the charts and analyzed.

Results

Patients with SFU grade 1, 2, and 3 hydronephrosis (n=125, n=74, and n=11, respectively) were followed for two years. In all, 2.4%, 18.9%, and 90.9% of patients with SFU grade 1, 2, and 3 hydronephrosis, respectively, underwent surgery. SFU grade 3 (HR=9.23, 95% CI: 1.43–59.74, p=0.02), APD (HR=2.81, 95% CI: 1.11–7.10, p=0.03), and parenchymal thickness (HR=0.42, 95% CI: 0.24–0.71, p=0.001) were independently associated with the occurrence of surgery. For anterioposterior diameter, using a cut-off point of 1.1, the area under the curve was 0.86, Youden index was 0.556, sensitivity was 70.4%, and specificity was 85.3%. For parenchymal thickness, using a cut-off point of 5, AUC was 0.79, Youden index was 0.478, sensitivity was 74.1%, and specificity was 73.8%.

Conclusions

Patients with SFU grade 2 hydronephrosis require long-term follow-up. Surgery and close postsurgical observation may be necessary for patients with SFU grade 3 and 4 hydronephrosis. An initial B-mode ultrasound screening at 7–10 days after birth may help make an optimal diagnosis and treatment selection.

Prenatal natural history of isolated fetal mild bilateral pyelectasis

OBJECTIVE

To analyze the prenatal outcomes in a cohort of fetuses with mild bilateral pyelectasis and determine whether performing serial ultrasounds is a good follow-up strategy.

METHODS

A prospective longitudinal study was conducted on 62 fetuses with mild bilateral pyelectasis. Fetal mild bilateral pyelectasis was considered when the renal pelvis measured (in millimeters) ≥5.0 to 10.0, ≥7.0 to 10.0, and ≥10.0 to 15 at ≤23 weeks 6 days, 24 to 31 weeks 6 days, and ≥32 weeks, respectively, with no uretero-calyceal dilatation. Ultrasounds were performed every 3 weeks to assess whether the mild bilateral pyelectasis regressed, remained unchanged (Group 1) or progressed (Group 2).

RESULTS

Group 1 consisted of 53 fetuses (85.4%), and progression was observed in 9 cases (Group 2, 14.6%). The initial renal pelvis diameter was significantly larger in fetuses with progression (p=0.028). Statistically significant differences in the renal pelvis diameter were also found at weeks 31 and 35 for both kidneys (p<0.05). The cases requiring intrauterine procedures or early delivery were not observed.

CONCLUSION

Fetal mild bilateral pyelectasis with no calyceal dilatation is a benign condition that can be managed in the postnatal period. The initial renal pelvis diameter and the diameter in week 31 or 35 were valuable parameters for identifying cases that would eventually need specific postnatal procedures.

Revised guidelines on management of antenatal hydronephrosis

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow-up investigations and indications for surgery in these patients.