Type 2 split cord malformation: the 'Martian' sign.

A 23-years-old female with congenital kyphoscoliosis was referred to us for further imaging and pain management. She had complained of mainly pain and numbness of the left lower limb. Magnetic resonance imaging (MRI) of the whole spine incidentally revealed type 2 split cord malformation; with longitudinal separation of the cord at the level of T4/5. The two hemicords are contained within the same dural sac. On axial T2 weighted MRI, the appearance of the two hemicords within the spinal canal was noted to have a stark resemblance to the face of a Martian (Figure 1A and B). We hence coined the name the ‘Martian’ sign to describe this novel radiological sign. Patient underwent nerve root injection and was pain free post-procedure; she remains under our follow-up. Type 2 split cord malformations (SCM) are rare spinal cord anomalies, characterized by the longitudinal separation of the spinal cord into two hemicords; which are contained within a single dural sac. Classification of SCM can be divided into two; namely type 1 when the two hemicords are enclosed within their own dural sac, and separated by a bony septum, whereas type 2 when both the hemicords are housed within a single dural sac.,

Figure 1

(A) T2 weighted MRI image of the spine (axial section), at the lower thoracic level, showing the two hemicords within the spinal canal. The features corresponding to a Martian’s face is labelled (arrows). (B) Graphical illustration of a Martian’s face.

Conflict of interest: None declared.