LAUSR

Fetal lower urinary tract obstruction (LUTO) is a rare congenital anomaly that occurs in 2 to 3 cases per 10 000 births as a consequence of an obstruction of the fetal bladder outlet (urethra). As a consequence, fetuses diagnosed with LUTO develop oligohydramnios or anhydramnios that causes pulmonary hypoplasia, the main cause of early neonatal mortality and morbidity (Potters' sequence). In addition, infants with prenatal diagnosis of severe LUTO are at increased risk to progress to end stage renal disease after birth. The ultrasound diagnosis of LUTO is feasible as these fetuses present with megacystis, in combination with a variable degree of hydro‐ureteronephrosis and oligohydramnion. Because of the severity of the condition, fetal surgery has been proposed for this situation several decades ago. There are different fetal surgical options of which vesicoamniotic shunting (VAS) has by far been best studied. The main objective of fetal intervention for LUTO is to prevent severe pulmonary hypoplasia and end stage renal disease by resolving or bypassing the obstruction. There is much debate in the fetal therapy community on the value of VAS in the treatment of LUTO, mainly relating to difficulties in selecting the fetuses that may benefit most from this intervention. Therefore, the question that was debated during the 2017 International Society for Prenatal Diagnosis (ISPD) meeting in San Diego, California, was whether all prenatally detected fetuses with LUTOs should be shunted or not. First debater―R Douglas Wilson MD (Canada)―Yes, all prenatally detected fetuses with lower urinary tract obstruction should be shunted.