OP25.03: The usefulness of 3D ultrasonography in determining the level of open spina bifida in the second trimester

Abstract

Objectives: The prognosis of infants with open spina bifida depends upon the location and extent of the lesion. This study aimed to determine the effectiveness of the 3D sonography on the prediction of upper pole of spina bifida during second trimester anomaly scan. Methods: Fetuses with spina bifida diagnosed during the second trimester from the October 2009 to the April 2010 were analyzed in two referral centers. Volumes were acquired starting from a midsagittal scan. The upper level of spina bifida was identified in multiplanar mode and maximum mode by comparing axial and sagitttal views, using as reference either the last rib (corresponding to T12) or the sacroiliac joint (S1). The diagnosis made on 3D was confirmed with pathological examination of aborted specimens and postnatal magnetic resonance imaging. Results: Fourteen fetuses were analyzed and the mean gestational age were 20.14 ± 2.11 (17–24). Six fetuses had thoracic spina bifida, six had lumbar defects and two had purely sacral defects. All had cranial signs of Arnold-Chiari malformation including lemon sign, banana sign and ventriculomegaly. Talipes was present in 12/14. Multiplanar mode was superior to the maximum mode in the identification of spina bifida level. This was correctly diagnosed in 10/14 (71, 43%). In the four remaining cases the sonographic estimate was within one vertebral segment (28, 57%). Conclusions: 3D sonography with multiplanar mode is an accurate tool in the diagnosis of open spina bifida level.