Congenital urethral atresia is generally considered to be incompatible with life unless there is either a patent urachus or vesicoamniotic shunt. Here we present the case of a male neonate with anhydramnios detected at 28weeks gestation due to urethral atresia, who was born without evidence of either a patent urachus or vesicoamniotic shunt, who has survived and is not requiring respiratory support at age 5months. While this is a thought-provoking clinical case, it also highlights the importance of early and effective parental engagement in cases of complex congenital anomalies of the urinary tract.

BACKGROUND: Intrauterine vesicoamniotic shunting (VAS) using a Somatex® shunt was shown to significantly affect survival of male fetuses with megacystis in suspected lower urinary tract obstruction (LUTO) [Figure 1]. Data on postnatal surgical management and complications are largely lacking.
OBJECTIVE: To describe the postnatal management of patients with prenatal VAS for megacystitis in suspected severe LUTO.
METHODS: All male newborns with previous intrauterine VAS using a Somatex® shunt treated in our institution were retrospectively analyzed. We evaluated the spectrum of urethral pathologies and postnatal surgical management, especially focusing on shunt removal.
RESULTS: Between 2016 and 2022, 17 patients (all male) were treated postnatally in our institution after VAS for suspected severe LUTO. Five fetuses with dislocated shunts underwent re-implantation in utero. Overall, premature birth before the 38th week of gestation was observed in eight patients (8/17). Seven shunts could be removed without further anesthesia as a bedside procedure. Ten patients required surgical shunt removal under general anesthesia due to migration (59%). Laparoscopic shunt extraction was performed in 8/10 cases. Most frequently, dislocated shunts were located incorporated in the detrusor in eight cases and the removal required a bladder suture in 2/8 patients. In one case, the shunt was removed from the abdominal wall and in one case from the intestine wall [Figure 2]. Posterior urethral valves were found in 8/17 patients, 6/17 patients showed a urethral atresia and one patient had urethral duplication. In two patients, we identified a high grade bilateral vesicoureteral reflux without LUTO.
CONCLUSIONS: In our observation, more than half of the newborns with megacystis in suspected LUTO require a shunt removal surgery after early VAS using a Somatex® shunt. Urethral atresia may be found more frequently in these patients. These data should be taken into consideration for prenatal counselling of parents and planning of postnatal management.

Lower urinary tract obstruction (LUTO) is a rare birth defect with a prevalence between 1 in 5,000 and 1 in 25,000 pregnancies. LUTO is one of the most common causes of congenital abnormalities of the renal tract. Several genetic conditions have been associated with LUTO. Most common causes of LUTO are posterior urethral valves and urethral atresia. Despite available prenatal and postnatal treatments, LUTO is a significant cause of morbidity and mortality in newborns causing significant end stage renal disease and pulmonary hypoplasia.

OBJECTIVE: To construct reference values for fetal urinary bladder distension in pregnancy and use Z-scores as a diagnostic tool to differentiate posterior urethral valves (PUV) from urethral atresia (UA).
METHODS: This was a prospective cross-sectional study in healthy singleton pregnancies aimed at constructing nomograms of fetal urinary bladder diameter and volume between 15 and 35 weeks\' gestation. Z-scores of longitudinal bladder diameter (LBD) were calculated and validated in a cohort of fetuses with megacystis with ascertained postnatal or postmortem diagnosis, collected from a retrospective, multicenter study. Correlations between anatomopathological findings, based on medical examination of the infant or postmortem examination, and fetal megacystis were established. The accuracy of the Z-scores was evaluated by receiver-operating-characteristics (ROC)-curve analysis.
RESULTS: Nomograms of fetal urinary bladder diameter and volume were produced from three-dimensional ultrasound volumes in 225 pregnant women between 15 and 35 weeks of gestation. A total of 1238 urinary bladder measurements were obtained. Z-scores, derived from the fetal nomograms, were calculated in 106 cases with suspected lower urinary tract obstruction (LUTO), including 76 (72%) cases with PUV, 22 (21%) cases with UA, four (4%) cases with urethral stenosis and four (4%) cases with megacystis-microcolon-intestinal hypoperistalsis syndrome. Fetuses with PUV showed a significantly lower LBD Z-score compared to those with UA (3.95 vs 8.83, P < 0.01). On ROC-curve analysis, we identified 5.2 as the optimal Z-score cut-off to differentiate fetuses with PUV from the rest of the study population (area under the curve, 0.84 (95% CI, 0.748-0.936); P < 0.01; sensitivity, 74%; specificity, 86%).
CONCLUSIONS: Z-scores of LBD can distinguish reliably fetuses with LUTO caused by PUV from those with other subtypes of LUTO, with an optimal cut-off of 5.2. This information should be useful for prenatal counseling and management of LUTO. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

OBJECTIVE: The purpose of this study was to evaluate the prenatal findings and postnatal outcomes in fetuses with congenital megalourethra.
METHODS: This retrospective study reviewed our experience and the literature between 1989 and 2014. Prenatal findings were evaluated and compared with postnatal findings, including neonatal mortality and abnormal renal function (need for dialysis or renal transplantation).
RESULTS: Fifty fetuses with congenital megalourethra were analyzed, including 6 cases diagnosed in our centers. Most cases (n = 43 [86.0%]) were diagnosed in the second trimester. Only 1 case was diagnosed in the first trimester, whereas 6 cases (12.0%) were diagnosed in the third trimester. Thirty-five fetuses (70.0%) survived. Bilateral hydroureters were associated with perinatal death (P= .024). Among the survivors, 41.9% of the neonates had renal impairment. The following factors were associated with postnatal renal impairment: presence of severe oligohydramnios/anhydramnios (P = .033), bilateral hydronephrosis (P = .008), and earlier gestational age at delivery (P = .022).
CONCLUSIONS: In fetal megalourethra, bilateral hydroureters, bilateral hydronephrosis, and severe oligohydramnios/anhydramnios are associated with neonatal mortality and renal impairment.

We report the case of a fetus with severe megabladder, displaying the \'keyhole\' sign on ultrasound imaging, that underwent cystoscopy at 22 weeks\' gestation. There was a familial history of mild urethral atresia. Fetal cystoscopy revealed congenital urethral atresia. A guide wire was advanced through the fetal urethra and a transurethral vesicoamniotic stent was placed successfully. The fetus was delivered at 36 weeks\' gestation and postnatal cystoscopy confirmed the absence of posterior urethral valves or urethral atresia. The infant was 5 years old with normal renal function at the time of writing. We conclude that fetal cystoscopic placement of a transurethral stent for congenital urethral stenosis is feasible.