Prenatal Assessment of the Position of Fetal Conus Medullaris as a Predictor of Fetal Spinal Lesions.

OBJECTIVES: The aim of this study is to compare two different methods in assessment of the position of fetal conus medullaris (CM) and to explore the significance for assessment of CM.

METHODS: This study included both normal fetuses and those with the diagnosis of fetal spinal lesions. The position of fetal CM was performed sonographically using two methods: location of CM in relation to the vertebral body (CM level) and measurement of the conus sacrum (CS) distance.

RESULTS: The results showed that intra-observer and interobserver concordance was high for the two methods, both in the normal and abnormal groups. There was significant association between femur length and CS distance (R2  = 0.917) and between gestational age and CS distance (R2  = 0.892).

CONCLUSIONS: We propose the combined use of CM level location and CS distance measurement for the prenatal diagnosis of fetal spinal lesions for complementary needs.