Level of conus medullaris in term and preterm neonates.

AIMS To compare the levels of conus medullaris in preterm and term neonates; to show the time of ascent to normal; and to evaluate the babies with low conus medullaris levels for tethered cord syndrome. METHODS Levels were assessed using ultrasonography in 41 preterm and 64 term neonates. RESULTS In the preterm group the conus medullaris level in one infant (2.4%) was below L4. In three infants (7.2%) it was between L2 and L3 and in 37 infants (90.4%) it was above L2. In the term group it was below L4 in one baby (1.6%), between L2 and L3 in four (6.3%), and above L2 in 57 babies (92.1%). The difference in the conus medullaris levels between term and preterm neonates and genders was not significant. Two patients, one with a conus medullaris level at L4-L5, and the other at L2-L3, had Down's syndrome. CONCLUSION The ascent of conus medullaris seems to occur early in life. It is important to follow up patients with conus medullaris levels at or below the 4th lumbar vertebra for the development of tethered cord syndrome.