VP09.05: Incorporation of screening for anorectal malformations in the detailed anatomic survey

Abstract

Anorectal malformations (ARM) are congenital abnormalities that occur in up to 1/1,250 births. Prenatal diagnosis can be challenging due to absent or late presentation on ultrasound. We instituted a practice change in 2016 to add a standard “bullseye” view of the fetal anus to our detailed anatomic survey exams performed in our fetal centre. This study aims to demonstrate our experience after adding this view over a 3-year period. This was a retrospective cohort of all neonates diagnosed with ARM from January 2017 to December 2019 at a single academic institution. We collected descriptive data including number, duration, and location of ultrasound exams and coexisting fetal anomalies. All available ultrasound reports and images were reviewed for inclusion and interpretation of the “bullseye” view. Prenatal and postnatal diagnoses were compared for accuracy along with any need for neonatal consultation with pediatric surgery or procedures. 28 neonates were identified with ARM during our study period. Two pregnancies were excluded due to lack of ultrasound data, thus 26 pregnancies were included in our analysis. We attempted visualisation of the bullseye in 20/26 patients during prenatal ultrasounds and diagnosed lower GI tract anomaly correctly in 80%. 90% of neonates born at our hospital without antenatal diagnoses of ARM were imaged at offices outside of our fetal centre. ARM was an isolated anomaly in 7 neonates, thus were at the highest chance to be missed with routine anatomic surveys. Imaging time stamps demonstrated a mean acquisition time to view the fetal anus of 1 min 38 seconds. The inclusion of the “bullseye” view in detailed anatomical surveys is a practical method for prenatal detection of ARM. With continued experience, we may expect improved accuracy and efficiency of this imaging technique. More accurate antenatal diagnosis may prompt delivery at centres with pediatric surgery consultation, thus avoiding neonatal transport.