Pediatric neurosurgery
-
Pediatric neurosurgery · Nov 1997
Normal diameter of filum terminale in children: in vivo measurement.
The hallmarks of tethered cord syndrome are a low-lying conus medullaris and a thick filum terminale. In diagnosing the tethered cord syndrome, the thick filum terminale is often defined as that greater than 2 mm in diameter. The cutoff of 2 mm in diameter was derived from myelographic measurements a few decades ago, and the true normal diameter of the filum terminale diameter in children or adults remains unknown. ⋯ The diameter of the filum at 10 and 15 mm caudal to the conus was 1,211 +/- 209 and 1,163 +/- 245 microm (mean +/- SD), respectively. In all children except one, the conus medullaris ended above the L2 level. The data indicate that filum terminales greater than 2 mm in diameter in children are abnormally thick.