C-Spine – Induction

Author: Charlotte Davies / Questions Charlotte Davies / Codes:  / Published: 06/02/2018

“Doctor to cubicle 5 for c-spine assessment please,” you hear over the tannoy. Unfortunately, you’re the only doctor around, and so, with a heavy heart, you pop to cubicle five, and try to think how you can assess the patient’s c-spine.

Assessing c-spines always used to fill me with dread, as I didn’t know what system to use, and I felt any missed injury would be significant. I still have a low threshold for imaging, but there are some patients, who just don’t need imaging – and there’s evidence to back it up. When I was an FY2 (a fair few year ago), one of my registrars said “Charlotte, to clear c-spines, you just need to have really big hairy balls”. And, whilst that’s language not ideal to be used, that is a sentiment that has still stuck with me, when clearing c-spines in the conscious patient!

The actual incidence of c-spine injury in blunt trauma victims is 2-12%, with less than 1% in walking, neurologically intact patients. C-spine injury also occurred in 10-20% of patients with serious head injury, and 1 in 300 serious motor vehicle accidents. Of these fractures up to 14% will be unstable. The rate of missed c-spine injury is low at 0.01%. C-spine injury also occurred in 10-20% of patients with serious head injury, and 1 in 300 serious motor vehicle accidents.

There are two main sets of decision rules to help decide which patients should be imaged. RCEM has its own guidelines based on modified Canadian C-spine Guidelines. If you were thinking that you’re better than the guidelines, think again – this is only 80% sensitive and 73.98% specific.

NEXUS Guidelines

NEXUS guidelines were the first set of guidelines created. They have a sensitivity of 99.6% with a 12.9% specificity- lower specificity than clinical judgement alone. The NEXUS study was large, and included lots of people, including children.

NEXUS looks at the following five points. If any one of these is present, you should have radiography:

* Focal Neurologic Deficit Present?
* Midline Spinal Tenderness Present?
* Altered Level of Consciousness Present?
* Intoxication Present?
* Distracting Injury Present?

So, I think NEXUS is where the incorrect approach of “lets poke their neck and if it’s sore get an x-ray” comes from. Midline spinal tenderness as a discriminator has been criticised as anyone has midline tenderness if you push hard enough, especially over C5 – and that will be one of the reasons the specificity is so low!

The authors of the NEXUS rules have not defined what a distracting injury is. Some say any pain scoring more than 5/10 on a scale of one to ten. Recent studies suggest distracting injuries are chest injuries, long bone fractures, visceral injury requiring surgeons, large laceration, large burns or any injury producing functional impairment. There’s a nice summary card from AliEM.

Canadian C-spine

The Canadian c-spine rules were validated in adult patients sustaining acute blunt trauma to the head or neck. The study excluded people with delayed presentation (more than 48hours), known vertebral disease, grossly abnormal vital signs and children. So this means that these rules have not been validated in children, and NICE guidelines say that using them in children, might be difficult. If you are worried about c-spine injury in a child, speak to a senior early, as the radiation risk to the developing thymus is significant.

The Canadian C-spine rule is a three step process. Unlike the NEXUS guideline, it considers high risk factors first: anyone over 65, with a dangerous mechanism or paraesthesia mandates radiography. Note that the canadian c-spine rule does not say x-ray or CT – and your department will have a strategy. Many departments will CT the >65s first, rather than x-ray, as x-rays are more likely to be abnormal in this group making a radiograph difficult to look at.

If there are no high risk factors, “safe” factors are looked at next. If any one (single) low risk factor is present, range of movement can be assessed. The low risk factors are:

• Simple rear end shunt motor vehicle collision
• Sitting position in ED
• Ambulatory at any time
• Delayed onset of neck pain
• Absence of midline neck tenderness

So, you only need one of these to move on to the next step. You can get to this point without having looked carefully at the patient! It’s really important to ask the patient when the neck pain started! The interesting thing (I think) is “if I have a “safe factor” and a “high risk” factor, does the “safe factor” outweigh the high risk factor. I haven’t done a full literature search on this, but a quick one said the high risk factor still counts. So, if your patient self presents after flipping their car, and walks in to the cubicle – you’re still going to image them.

If they have any single low risk factor, you can then move on to see if they can rotate their neck. If they can, to more than 45 degrees,  they don’t need radiography!

Once the patient has cleared their own neck, I find it useful to give them a little exercise to do, based on the Feldenkrais method. Ask the patient to rotate their neck and look at what they can see. Then ask them to close their eyes, and imagine what they see when they move their neck. Then they can open their eyes and rotate their neck again. In the vast majority of people their range of movement improves!! Obviously, only do this once you have cleared their neck, and don’t use it as part of the process to clear their neck!

The NICE guidelines for imaging the c-spine are the Canadian C-spine rules in a different format.

The RCEM guidelines use modified canadian c-spine guidelines. They have added two further risk factors:
* Severe neck pain (>7/10)
* Known vertebral disease

It’s worth having a look at the RCEM guidelines as they talk through all of the evidence.

Once you’ve decided you can clear the neck, go ahead and treat the rest of the patient. Clearing the c-spine does come into “airway + c-spine control”, one of your first steps in assessing a trauma, but that doesn’t mean you need to clear it straight away. If you’re not sure, keep the neck immobilised and discuss with a senior. If they have another immediate life threat, keep the c-spine immobilised, deal with the life threat, and run through the decision rules later!

If you can’t clear the neck, discuss with a senior whether to CT or x-ray the patient, as this will depend on the presentation and your departmental protocols. Whether to immobilise the patient or not is another thorny issue – stick with your departmental protocol.

Remember, these decision rules are all based on acute presentations – they’re not for the patient who comes to the ED with persisting pain two weeks after trauma.

Want to know more? Have a look at our induction guide to restriction of c-spine movement (immobilisation) here. RCEMLearning has a reference section and a learning module, if you want to have a look at that.