Section of the filum terminale: is it worthwhile in Chiari type I malformation?

A section of the filum terminale (SFT) is used for the surgical treatment of isolated tethered cord or that resulting from neurulation disorders. More recently, it has been proposed for the management of the occult tethered cord syndrome (OTCS), though it is still under debate. Even more controversial appears to be the use of SFT in patients with Chiari type I malformation (CIM), which is based on the possible presence of OTCS. This review shows that: (1) there are issues both in favor and against the occurrence of OTCS, (2) there is no significant correlation between CIM and tethered cord, the old "caudal traction theory" being not supported by clinical or experimental evidences. On these grounds, a relationship between CIM and OTCS is hard to be demonstrated, (3) a subgroup of patients with CIM suffering from OTCS may exist and benefit from SFT.