Hindbrain Herniation and Banana and Lemon Sign After Open Fetal Myelomeningocele Repair - When Do These Signs Disappear and is Shunting Predictable?

PURPOSE: The aim was to describe the sonographic follow-up of hindbrain herniation (HH), the banana and lemon sign after fetal myelomeningocele (fMMC) repair, and the time of disappearance of these signs after the intervention, and to investigate any predictive value for the necessity of shunting during the infant's first year of life. Additionally, the sonographic evolution of the transcerebellar diameter (TCD) before and after fetal intervention was assessed. PATIENTS AND METHODS: The first 50 patients that underwent fMMC repair at Zurich Center for Fetal Diagnosis and Therapy (www.swissfetus.ch) were included in this study. Sonographic scans performed weekly after fMMC repair focusing on HH and banana and lemon signs were analyzed and compared between the shunted and the non-shunted group. ROC curves were generated for the time intervals of resolution of the signs in order to show their predictive accuracy for the need for shunting until 1 year of age. RESULTS: HH resolved in 48 fetuses (96 %) before delivery. The sonographic disappearance of HH within the first two weeks after fMMC repair was associated with a significantly lower incidence of shunt placement (OR 0.19; 95 % CI 0.4-0.9) during the first year of life (p = 0.03). All fetuses with persistent HH before delivery received a shunt. TCD growth was observed in all fetuses. CONCLUSION: The reversibility of HH within two weeks after fMMC repair is associated with an 80 % lower incidence of shunt placement during the infant's first year of life. Moreover, it allows the cerebellum to grow and to normalize its configuration.

Prenatal Sonographic Head Circumference and Cerebral Ventricle Width Measurements Before and After Open Fetal Myelomeningocele Repair - Prediction of Shunting During the First Year of Life.

PURPOSE: The aim of this study was to describe the sonographic evolution of fetal head circumference (HC) and width of the posterior horn of the lateral ventricle (Vp) after open fetal myelomeningocele (fMMC) repair and to assess whether pre- or postoperative measurements are helpful to predict the need for shunting during the first year of life. PATIENTS & METHODS: All 30 children older than one year by January 2017 who previously had fMMC repair at the Zurich Center for Fetal Diagnosis and Therapy were included. Sonographic evolution of fetal HC and Vp before and after fMMC repair was assessed and compared between the non-shunted (N = 16) and the shunted group (N = 14). ROC curves were generated for the fetal HC Z-score and Vp in order to show their predictive accuracy for the need for shunting until 1 year of age. RESULTS: HC was not an independent factor for predicting shunting. However, the need for shunting was directly dependent on the preoperative Vp as well as the Vp before delivery. A Vp > 10 mm at evaluation for fMMC repair or > 15 mm before delivery identifies 100 % of the infants needing shunt placement at a false-positive rate of 44 % and 25 %, respectively. All fetuses with a Vp > 15 mm at first evaluation received a shunt. CONCLUSION: Fetuses demonstrating a Vp of > 15 mm before in utero MMC repair are extremely likely to develop hydrocephalus requiring a shunt during the first year of life. This compelling piece of evidence must be appropriately integrated into prenatal counseling.