"Axoatlantoidea" is a rather unusual variant; the usual form is "atlantoaxoidea". It's an adjective referring to the very top part of the spine, between the first and second cervical vertebrae, which are respectively called the atlas (C1) and the axis (or epistropheus) (C2). The atlantoaxial (or atlanto-axial) joint is the joint between these two; it is actually four distinct joints.
https://en.wikipedia.org/wiki/Atlanto-axial_joint

I think CV has its normal meaning of columna vertebral. Axoatlantoidea is an adjective. So it means the "columna vertebral axoatlantoidea". In English I think we would call this the atlantoaxial region of the spine. The abbreviation VC for vertebral column is also used.

It doesn't quite say that the patient has suffered an atlantoaxial dislocation (AAD), which is extremely serious and can be fatal, but a "dislocation-type injury".

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Note added at 49 mins (2018-08-13 18:37:03 GMT)
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"La columna cervical se divide en dos porciones:
- la columna atlantoaxoidea, que incluye la base del cráneo, C1 y C2.
- la columna subaxial, por debajo de C2 con vertebras anatómicamente
similares a las torácicas y lumbares"
https://documen.site/download/manejo-de-la-via-aerea-en-la-i...

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Note added at 51 mins (2018-08-13 18:39:07 GMT)
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So "CV axoatlantoidea" is another way of saying "CV atlantoaxoidea" or "columna atlantoaxoidea", meaning the upper portion of the cervical spine.