If you want to understand this post you probably need to listen to the episode on c-spine imaging approach and the follow-up regarding the evidence behind it.

 

Mike Wells from Scotland Writes:

Hi Scott,

Your two excellent podcasts on C spine imaging really got me thinking.

I work in the UK where resource constraints within our public

healthcare system mean that even if I wanted to, I would not be able

to obtain CTs as the first imaging port of call for all my neck trauma

patients. I can however argue individual cases with the radiology

department and therefore effectively need to try to choose high risk

patients.

I pulled the Canadian C spine and NEXUS studies and looked back

through their methodology and results. In both studies ordering a neck

CT was at the discretion of the treating physicians - but most

patients only got plain C spine films (in CCspine 436 patients got CTs

= 7% of total patients who were imaged; for NEXUS I could find data to

allow me to make this calculation). I also went through the further

NEXUS study looking at missed fractures - another way of looking at

their data is that in the 581 patients with technically adequate C

spine films, only 3 unstable fractures were missed - giving a

sensitivity of 99.4% for the unstable injuries which I am most scared

of missing.

I absolutely agree with you though that very often plain films are

technically inadequate and that their sensitivity is therefore much

lower.

However I would argue that the real sensitivity we are interested in

is not that of C spine films alone, but rather than the sensitivity of

the combination of plain C spine films and clinical examination and

acumen. CTs in the NEXUS and Canadian studies were after all ordered

at clinician discretion. It's possible that fractures were missed in

the patients who weren't scanned but both studies did seem to attempt

follow up (NEXUS in particular checked local 'event logs' although I'm

not clear on what these are).

So I think over here in the NHS I would argue that in 'minor' trauma

patients failing the CCspine rule I am still obliged to use plain C

spine films as my first imaging step. On the basis of what you have

said I'll will set the bar higher in terms of making sure films are

technically adequate (over here we still use Swimmer's views, which I

detest). However for patients with adequate films and the roughly 3%

prevalence of fractures in the group failing Canadian C spine, I would

hope that my clinical exam would then identify those patients with

normal films but underlying injuries.

Utimately I think from my view what this is about is not the

sensitivity of plain films on their own - which I agree is

unacceptably low - but about the sensitivity of plain films + clinical

skills.

Please feel free to put this in your comments section if you wish!

Thanks again for your fantastic podcast and blog.

Best wishes

Mike Wells

Here is my response to Mike and the others who voiced similar questions about what to do when CT is not easily obtained...