P03.01: Prenatal diagnosis of closed spinal dysraphism

Abstract

To observe ultrasound features seen in 14 fetuses with closed spinal dysraphism. Clinical records from the spina bifida clinic at BC Children's Hospital were reviewed to identify 12 children born with radiological and/or surgical evidence of spinal lipoma. In all 12 cases, prenatal ultrasounds had been performed and images were available for retrospective review. 2 additional cases were identified prospectively on prenatal ultrasound and MRI with other forms of closed spinal dysraphism. In all 14 cases of closed spinal dysraphism, the posterior fossa was normal on prenatal sonography. There was no evidence of the Chiari II malformation, and there were no cases with ventriculomegaly. In six children with spinal lipoma diagnosed after birth, no prenatal sonographic abnormalities were seen. In 8 out of 14 cases of closed dysraphism, prenatal sonographic abnormalities were identified, including: cystic and/or solid mass dorsal to the spine (5 cases); vertebral abnormalities (4 cases); foot deformities (2 cases); diastematomyelia (1 case); and abnormally low conus in one fetus with cloacal dysgenesis. MSAFP was negative in 3 cases and elevated in 1 case; AFAFP was elevated in 1 other case. Eight out of 14 fetuses with closed dysraphism had prenatal sonographic findings of soft tissue masses, vertebral and/or foot abnormalities, or low conus. Spinal lipoma was detected antenatally in 6 out of 12 cases. None of the 14 cases showed any sonographic evidence of a Chiari II malformation, ventriculomegaly, or other intracranial abnormality. Due to the relative subtlety of the prenatal findings, the diagnosis of closed spinal dysraphism is considerably more difficult than it is with open dysraphism.