How is a C-spine xray performed?
From WardWiki - Foundation Doctor Helper
How a C-spine is performed is crucial to its interpretation and can easily lead to serious adverse neurological consequences! There are important features to all the views in this article and these must be appreciated. This article features the use of c spine xray as part of a trauma series used in primary survey
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What is an Xray
A shadow produced by tissue attenuation of a point source xray beam. A combination of density and depth produce attenuation, hence a rib can appear less white than the liver on xray. The distance from the source influences the size of the projected shadow. The heart is closer to the source and projects as a larger shadow on AP view; this is why an AP view should not be used for interpreting cardiothoracic ration.
Principles of cervical spine imaging
One must confidently by able to comment on the following as described by the royal college of radiology.
Is C1/2 properly seen on lateral view?
Is upper end plate of T1 visualised on lateral view?
Has an adequate Peg view been obtained?
Is AP view adequately positioned and exposed?
If the answer to any of the above is No Was further imaging (additional views, CT, MRI obtained)?
If Plain films were inadequate as assessed above and further imaging not obtained was this indicated in the report?
Canadian C-spine rules
These form a very useful guide to requesting cerival spine xrays and are evidence based. Proceed to xray if there is a high risk feature, a lack of low risk features allowing neck rotation, or when neck rotation is painful.
High risk features?
Age ≥ 65 / Extremity Paresthesias / Dangerous Mechanism fall from ≥ 3ft / 5 stairs axial load injury high speed RTA/rollover/ejection bicycle collision
Low risk factors that allow assessment of neck rotation
Sitting Position in the ED, Ambulatory at any time, Delayed (not immediate onset) neck pain, No midline tenderness Simple rearend MVC? MVC not simple if:
- pushed into traffic,
- hit by bus/large truck, rollover,
- hit by high-speed vehicle
Ability to actively rotate neck 45° left and right
This is a check once low risk factors allowing for assessment have been confirmed. if there is pain on lateral rotation up to 45 degrees proceed to xray. Do NOT rotate further once pain is elicited!!
Positioning
This is not simply the job of the radiolographer. be sensible and helpful. This is a particularly distressing xray for the patient as he is forcibly immoblised by a very uncomfortable collar and likely frightened that a neck injury is suspected. Think in advance about this xray will be carried out. The patient is supine ( flat on back) for C-spine xrays.
Safe approach
The patient must either be calm or cooperative or arrangements for sedation should be made. Imaging a C spine with a moving patient will give poor images. Anticipate this.
Remove obstacles
Tubes, lines, jewellry can all prevent good views being obtained. Disconnect ECG wires or move well away from the neck and have nurses remove facial jewellery prior to imaging. For CT this is NOT required.
Swimmers view
This is used to image the lower cervical spine. Occaisionly you may be asked to pull firmly on the arms to lower the shoulders. Do NOT accept a C-spine xray unless T1 has been seen. Muscular adults may require a swimmers view due to soft tissue bulk obscuring the C-spine.
Malrotation
It is very easy to miss an injury due to malrotation. The butterfly sign classically gives this away. Being present at time of xraying can help avoid this but one must keep a keen eye out for this; it has fooled many clinicians bigger and uglier than the average foundation doctor.
