Aims-To compare the levels of conus medullaris in preterm and term neo
nates; to show the time of ascent to normal; and to evaluate the babie
s 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 o
ne 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 medull
aris levels between term and preterm neonates and genders was not sign
ificant. 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 con
us medullaris seems to occur early in life. It is important to follow
up patients with conus medullaris levels at or below the 4th lumbar ve
rtebra for the development of tethered cord syndrome.