Co-Authors: Lindsay Buzzelli Yeh, MD MEd, OBGYN, PGY2, University of Texas - Southwestern, Dallas, TX; Allison Gurney-McMaster, MD, MFM, PGY5, University of Texas - Southwestern, Dallas, TX; Patricia Santiago-Munoz, MD, MFM, Professor, University of Texas - Southwestern, Dallas, TX

Introduction: Dandy-Walker is a common posterior fossa malformation, with phenotypes ranging from mild to severe. Diagnosis is usually made prenatally on ultrasound by fourth ventricle dilation that fills the posterior fossa and cerebellar vermis hypoplasia. In extremely rare cases, it can be associated with brainstem disconnection. In this condition, only a thin cord of tissue connects the superior and inferior portions of the brainstem.1 There exist only 14 known cases of brainstem disconnection.2 The vast majority were not diagnosed prenatally and were almost universally lethal in the months following delivery.3

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2. Vekemans M, Maurice P, Lachtar M, et al. Additional evidence for the vascular disruption defect hypothesis in a novel case of brainstem disconnection syndrome. Birth Defects Research. 2022;114(19):1298-1306. doi:10.1002/bdr2.2100
3. Duffield C, Jocson J, Wootton-Gorges SL. Brainstem disconnection. Pediatric Radiology. 2009;39(12):1357-1360. doi:10.1007/s00247-009-1378-3