RESUMO
Objective:To investigate the prenatal ultrasound findings and clinical prognosis in fetal closed spina bifida without subcutaneous mass.Methods:This retrospective study included nine fetuses diagnosed with closed spina bifida without subcutaneous mass by prenatal ultrasound in Women's Hospital of Jiangnan University from October 2016 to February 2022. Descriptive analysis was used to summarize the ultrasonographic features, MRI findings, genetic testing results, pregnancy outcomes and follow-up data.Results:The diagnosis of fetal closed spina bifida without subcutaneous mass was confirmed in all cases by MRI, X-ray examination or ultrasound after termination or neonatal surgery. Four cases presenting with various degrees of sacral vertebra defects had caudal regression syndrome complicated by other malformations. Two cases had dermal sinus, presenting with subcutaneous hypoechoic sinus tract connecting to the spinal canal. Lipoma terminalis were found in two fetuses who presented with intraspinal hyperechoic mass. One fetus with diastematomyelia showed short linear strong echoes and double spinal cord echoes in the spinal canal with butterfly vertebrae. The location of the conus medullaris was lower in seven cases and normal in one fetus. The other one case had unclear position of the conus medullaris. No postoperative complications occurred in the two cases (one with dermal sinus and one with lipoma terminalis) receiving postnatal surgery and both infants grew and developed normally. Fetal death occurred in one case and six pregnancies were terminated.Conclusions:Closed spina bifida without subcutaneous mass typically has ultrasonographic features. Detection of spinal cord echoes in the spinal canal can improve the prenatal detection rate. Whether it is complicated with malformation affects its prognosis. Prenatal ultrasound diagnosis may provide information for prognosis consultation and postpartum treatment.