DIASTEMATOMYELIA or split cord malformation is a rare phenomenon that may be discovered on magnetic resonance imaging of the spine. These images are from the case of a 29-yr-old woman with back pain without neurological symptoms. She also had spina bifida occulta. Figure A is an axial T2-weighted image at the T12 level demonstrating diastematomyelia with two hemicords sharing a single dural sac. A mid-sagittal image from the same scan is relatively unremarkable (fig. B).
Diastematomyelia is typically associated with vertebral anomalies.1 Type 1 involves two hemicords with separate dural sacs and accounts for 40% of cases; it commonly causes neurological symptoms in childhood because of cord tethering. Type 2, seen here, involves the hemicords sharing a single dural sac and accounts for 60% of cases; it is usually asymptomatic.2 Splitting typically occurs between T9 and S1 but has been reported at cervical levels. There is no correlation between the level of splitting and the neurological symptoms.2
Neuraxial anesthesia must be carefully considered. If vertebral anomalies are present, the epidural space may be absent, and attempts to access it may result in dural puncture. There is a case report of successful spinal anesthesia on a parturient with undiagnosed type 2 diastematomyelia, although she did experience a right leg paresthesia during needle placement, as well as a transient left radiculopathy after resolution of the anesthetic.3 There are no reports of spinal anesthesia in patients with type 1, but the separation of dural sacs may result in a unilateral or unexpected distribution of anesthesia.
The authors declare no competing interests.