TABLE OF CONTENTS
KEY
🔍 | Deep Dive |
📌 | Clinical Application |
🔸 | Weak Evidence |
🔹 | Strong Evidence |
📑 | Evidence summaries |
✅ | Recommended treatment |
⚠️ | Critical Information |
💡 | Extra Reading |
❗ | Caveats |
A trauma patient arrives in the ED. The ED physician immediately applies manual in-line stabilisation (MILS) and places a cervical collar.
Was that the right thing to do?
The answer is more nuanced than a simple yes or no.
To understand whether our physician acted appropriately, we need to look at the evidence behind spinal motion restriction, cervical collars, and current trauma guidelines.
Before we dive in, a small warning.
Usually, when I write these articles, the challenge is finding enough evidence. This time, the problem is the exact opposite.
There is a huge amount of literature on cervical collars and spinal motion restriction, much of it conflicting. I've tried to keep things concise, but I apologise in advance for the inevitable barrage of references that follows.
There is a huge amount of literature on cervical collars and spinal motion restriction, much of it conflicting. I've tried to keep things concise, but I apologise in advance for the inevitable barrage of references that follows.
One other caveat:
This article focuses exclusively on adult trauma patients. Pediatric cervical spine assessment and immobilisation is an entirely different beast and deserves an article of its own.
“One of the first duties of the physician is to educate the masses not to take medicine.” — William Osler
Why Do We Apply a Cervical Collar?
Before discussing whether cervical collars are useful, it is worth asking why they were introduced in the first place.
The fundamental concern is straightforward:
This concept remains central to modern trauma care.
The 11th edition of ATLS states,
"Excessive movement of the spine with spinal column injury can exacerbate existing injury or create injury to the spinal cord"
Despite their rarity, missing one can have catastrophic consequences, leading to permanent neurological deficits, disability, and substantial healthcare costs. This explains why we have historically adopted an overly cautious approach to spinal protection and imaging [3].
The question of "Secondary Injury"
- Primary spinal cord injury results from blunt or penetrating mechanisms at the time of the initial traumatic event.
- Secondary spinal cord injury occurs after primary spinal cord injury due to insults from other factors, such as hypoxia and hypoperfusion.
Much of the acute management of spinal cord injury is aimed at preventing secondary spinal cord injury.
Historically, it was proposed that 3–25% of spinal cord injuries were secondary injuries occurring during prehospital transport or early hospital care as a result of inadequate spinal immobilisation [5].
This belief became one of the major drivers behind the adoption of cervical collars and spinal immobilisation practices.
However, this theory deserves closer scrutiny.
The evidence supporting these estimates is limited and subject to several important criticisms [5] :
- Neurological deterioration during the prehospital phase is often difficult to accurately identify and document.
- Many studies were performed decades ago under very different trauma systems and treatment standards.
- Findings from hospital-based studies may not be directly applicable to prehospital care.
- Neurological deterioration may result from other mechanisms such as cord oedema, hematoma expansion, hypoxia, hypotension, or inflammation rather than spinal movement alone.
In other words, while the possibility of secondary injury remains plausible, the exact contribution of spinal movement to neurological deterioration is far less certain than many clinicians assume.
Nevertheless, the fear of causing a preventable spinal cord injury has shaped decisions regarding cervical spine imaging and immobilisation. They are largely based on a "play it safe" philosophy.
Should We Apply Cervical Collars?
Rigid cervical collars have been a cornerstone of trauma care, yet high-quality evidence supporting their use is remarkably sparse. Randomised controlled trials are largely absent, and many aspects of current practice are based more on historical precedent [5].
At the same time, evidence demonstrating the complications of prolonged cervical collar use continues to grow.
The Harms of Cervical Collars
Most clinicians are familiar with the more obvious complications:
- Pressure ulcers and skin breakdown
- Increased intracranial pressure
- More difficult airway management
- More difficult central venous access
- Impaired oral hygiene and increased risk of ventilator-associated pneumonia
- Delayed mobilization and physiotherapy
- Increased risk of venous thromboembolism
- Increased nursing workload
Less obvious are the downstream consequences of prolonged immobilisation. Patients may experience nutritional difficulties, aspiration risk, ileus, prolonged ICU stays, and reduced overall mobility.
- Several studies have demonstrated that the risk of pressure injury increases with every additional day spent in a collar.
- Powers et al. reported skin breakdown in almost 7% of ICU patients who remained immobilised for more than 24 hours, with duration of collar use being the strongest predictor [6].
- ATLS notes that approximately 5% of patients with TBI have an associated spinal injury, while 25% of patients with spinal injury have at least a mild TBI. Cervical collars may increase intracranial pressure and potentially worsen secondary brain injury [5].
These complications rarely generate headlines. A missed cervical spine injury is dramatic, memorable, and medicolegally significant. Pressure ulcers, pneumonia, venous thromboembolism, and prolonged immobility are far less visible.
As a result, the risks of immobilisation have historically received much less attention than the risks of missing an injury.
Are We Overestimating the Risk of Movement?
The rationale behind collars, as I mentioned before, assumes that small movements of an injured spine can cause significant neurological deterioration.
However, this assumption has increasingly been questioned.
Several authors have pointed out that considerable force is usually required to produce an unstable spinal injury in the first place. It is therefore plausible that the low-energy movements encountered during routine patient care may be less dangerous than traditionally assumed [5].
Furthermore:
- Awake patients often maintain a relatively stable neck position through protective muscle activity [5].
- Minor degrees of cervical movement may be clinically insignificant in many injuries [5].
- Improperly fitted collars may provide little motion restriction while introducing additional complications [5].
"There are no data in the published literature to support spinal immobilisation and spinal motion restriction as standard of care."
The authors suggested that efforts to reduce cervical collar use should be considered and that devices such as backboards and vacuum splints should largely be limited to active patient extrication [10].
While some authors have argued that collars cause more harm than good and should be abandoned entirely, a more reasonable position is that not every movement of the neck inevitably translates into spinal cord injury.
That brings us to the most important practical question of all:
Who Should Receive a Cervical Collar?
Current trauma guidelines on prehospital care recommend SMR only when there is a reasonable suspicion of spinal injury. According to both ACS and NAEMSP guidance, indications for SMR following blunt trauma include [2,4] :
- Altered level of consciousness (including intoxication)
- Midline neck or back pain and/or tenderness
- Focal neurological symptoms or deficits
- Anatomical deformity of the spine
- Distracting injuries or circumstances that impair the patient's ability to participate in a reliable examination
In simpler terms, for patients who are obtunded or otherwise unevaluable, maintenance of cervical spine motion restriction remains the standard of care until appropriate assessment can be completed.
When SMR is indicated, it should be applied to the entire spine because non-contiguous spinal injuries may occur.
Backboards are not treatment devices. Once the patient reaches the hospital, they should be removed from long backboards as soon as practical to reduce discomfort and prevent pressure injuries.
A patient lying supine on a firm hospital stretcher achieves a degree of spinal motion restriction comparable to remaining on a backboard [2].
Finally, there is no routine role for spinal motion restriction in isolated penetrating trauma unless there is evidence of neurological injury suggesting spinal involvement [4].
Clinical Decision Rules: Can We Avoid Imaging?
Not every trauma patient with neck pain requires imaging.
In fact, one of the biggest advances in cervical spine assessment over the last three decades has been the development of clinical decision rules that allow clinicians to safely identify patients at extremely low risk of cervical spine injury.
The two most widely used tools are the NEXUS Criteria and the Canadian Cervical Spine Rule (CCR) [7,8].
The practical purpose of both rules is simple:
To identify patients who do not require cervical spine imaging.
If a patient cannot be cleared using one of these rules, imaging is indicated.
The NEXUS Criteria
The NEXUS Criteria can be used in alert, stable patients following blunt trauma.
Imaging is not required if all of the following are absent:
- Midline cervical tenderness
- Focal neurological deficit
- Altered alertness
- Intoxication
- Distracting injury
A useful mnemonic is: NSAID
- Neuro deficit
- Spinal tenderness
- Altered alertness
- Intoxication
- Distracting injury
The original NEXUS validation study included more than 34,000 patients and demonstrated a sensitivity of 99.6% for clinically significant cervical spine injury [9].
There are caveats to remember here.
- Midline tenderness is present if the patient says :
- Pain on palpation of the posterior midline neck from the nuchal ridge to the prominence of the first thoracic vertebra
- With direct palpation of any cervical spinous process.
Or
- A patient is considered intoxicated if
- There is a recent history
- Evidence of intoxication on physical examination or investigation.
Or
- An altered level of alertness is
- A GCS of 14 or less
- Disorientation to person, place, time, or events
- Inability to remember three objects for five minutes
- A delayed or inappropriate response to external stimuli
- No precise definition of painful distracting injury is possible.
- It is any condition thought by the clinician to be producing pain sufficient to distract the patient from a neck injury.
- This cannot be applied to patients with penetrating trauma
- Also, there is literature to suggest caution when applying NEXUS to patients >65 years of age [10].
Anyways, applying the NEXUS Criteria would allow physicians to safely reduce imaging by 12-36%.
The Canadian Cervical Spine Rule
The Canadian Cervical Spine Rule is another highly validated decision tool used in alert, stable patients with blunt trauma.
Unlike NEXUS, it uses a three-step approach:
Step 1: Look for high-risk features
- Age >65 years
- Dangerous mechanism
- Extremity paresthesia
Step 2: Look for low-risk features
- Simple rear-end collision
- Delayed onset of neck pain
- Sitting position in the ED
- Ambulatory after injury
- No midline cervical tenderness
Step 3: Assess range of motion
- Ability to actively rotate the neck 45° left and right
If the patient successfully passes all steps, imaging can be safely avoided.
But it is necessary to know the exclusion criteria (or who you shouldn't apply this to)
- Age <16 years old
- GCS <15
- Unstable vital signs.
- Injured >48hrs previously
- Penetrating trauma
- Acute paralysis
- Known vertebral disease
- Pregnant
- Non-trauma patients.
NEXUS or CCR?
This is one of those debates that generates far more discussion than it deserves.
Now let's compare both: CCR vs NEXUS
- CCR was more sensitive than the NLC (99.4 % vs. 90.7 %) and more specific (45.1 % vs. 36.8 %) for injury, and its use would have resulted in lower radiography rates (55.9 % vs. 66.6 %).
- The CCR would have missed 1 patient, and the NLC would have missed 16 patients with important injuries.
- But,
- Physicians were slightly less comfortable and accurate using the CCR, and that range of motion was not always evaluated.
- There was a slightly higher rate of misinterpretation for the CCR, which may reflect the fact that this rule is more complex.
- Found that the Canadian rules were slightly better (the difference being 99.6% vs 100% sensitivity)
- Both sets of criteria have the distinct disadvantage of producing a lot of unnecessary imaging, but the Canadian rules are slightly less likely to cause inappropriate irradiation (they reduced imaging rates to 55.9%, as compared to 66.6% for the Nexus criteria).
Also, the trial was performed by the creators of the CCR at hospitals that were involved in the initial CCR validation study, leading to some concerns about the generalizability of the study findings.
In summary, the Canadian C-Spine Rule may be slightly more sensitive and specific than NEXUS while reducing imaging rates. The trade-off is that it is more complex and therefore somewhat harder to remember and apply correctly.
Fortunately, both rules perform extremely well when used appropriately.
The most important point is not which rule you choose. The important point is that you consistently apply a validated rule rather than relying entirely on gestalt.
Who Should Not Be Cleared Using These Rules?
It is important to note here that both NEXUS and CCR have been developed for stable, blunt trauma patients.
Beyond that, ACS TQIP imaging guidelines stress that NEXUS and CCR criteria are not applicable for the pediatric patient or the older adult patient (55 years and older) [3].
What Does This Mean in Practice?
After all the discussion about NEXUS, CCR, sensitivities, specificities, and validation studies, the practical message is remarkably simple:
If a patient cannot be safely cleared using a validated clinical decision rule, cervical spine imaging is indicated.
Conversely, an awake, alert trauma patient with:
- A normal neurological examination
- No midline cervical tenderness
- No distracting injury
- Full active range of motion of the neck
- No high-risk features
Patients who fail clinical clearance should undergo appropriate radiographic evaluation, with CT being the preferred imaging modality in modern trauma practice. Until cervical spine clearance has been completed, spinal motion restriction should be maintained.
What about patients who are not cleared by these rules?
Once a patient fails clinical clearance using NEXUS or the Canadian C-Spine Rule, the next question becomes:
What imaging should we obtain?
The answer, for most adult trauma patients, is straightforward:
CT is the imaging modality of choice.
Modern multidetector CT scanners have demonstrated excellent sensitivity for clinically significant cervical spine injuries and have consistently outperformed plain radiography.
As a result, CT is now recommended as the primary imaging modality by ACS, EAST, ACR, and most contemporary trauma guidelines [13,17,2].
Slices of no greater than 3 mm are recommended to obtain reformatted images in axial, coronal, and sagittal planes in the cervical spine by ACR [18].
This recommendation extends to obtunded patients as well.
In fact, EAST conditionally recommends cervical collar removal after a negative high-quality CT scan alone in obtunded blunt trauma patients [19].
But once again, there are caveats to these recommendations
- It is based on very low-quality evidence
- The use of this approach may result in a nonzero rate of neurologic deterioration.
But Is CT Enough?
This depends on the question being asked.
- It picks up 97% of bony injuries
- It picks up 86% of subluxation injuries
- It misses 75% of ligamentous injuries
But CT is not designed to evaluate the spinal cord itself.
- It misses 100% of spinal cord injuries
MRI is the only modality for evaluating the internal structure of the spinal cord
So why not perform an MRI on Everyone?
The problem is that greater sensitivity does not always translate into better patient care.
MRI frequently identifies additional abnormalities after a normal CT scan, particularly ligamentous injuries. However, the overwhelming majority of these findings do not alter management.
- A prospective study has concluded that, for all its disadvantages, the CT picks up 99.75% of clinically significant C-spine injuries [20].
- While MRI revealed a variety of extra ligamentous injuries that the CT had missed, none were clinically significant [21].
- Also, EAST performed a systematic review in 2015 of obtunded patients with negative CT c-spine and found that 176 patients had abnormal MRI but none of them had had unstable C-spine injury [22].
Routine MRI after a normal CT has several disadvantages:
- Increased cost
- Reduced availability
- MRI-incompatible implants
- Delays in cervical collar removal
- Prolonged immobilization
- Increased ICU and hospital length of stay
- Higher false-positive rates [23]
For these reasons, modern trauma practice has increasingly shifted toward CT-based clearance strategies.
When Should an MRI Be Obtained?
The EAST guidelines suggest MRI imaging should be carried out in cases of neurological deficit.
However, there is a risk that ligamentous injuries may be missed, although these injuries are rare and the risk of them being unstable is low (<0.1%) [13].
However, there is a risk that ligamentous injuries may be missed, although these injuries are rare and the risk of them being unstable is low (<0.1%) [13].
Situations that should raise concern include:
- Motor weakness
- Sensory deficits
- Bowel or bladder dysfunction
- Unexplained neurological findings
- Subtle signs of a SCI, such as tachypnea.
- Neurogenic shock - shock with bradycardia
What About X-ray?
The short answer? Don't.
Historically, cervical spine evaluation relied on a three-view radiographic series consisting of:
- Lateral view
- AP view
- Open-mouth odontoid view
The problem is that plain radiographs miss a substantial number of clinically important injuries.
Plain films have a sensitivity ranging from 45 to 64 percent while modern helical cervical CT scans have a sensitivity as high as 100 per cent [2]
Both ACS and EAST guidelines consider plain radiographs inadequate for cervical spine clearance [13,2].
What About Flexion-Extension Films?
These have largely fallen out of favour in the era of high-resolution CT. Modern guidelines do not recommend flexion-extension films as part of the initial clearance process [24,2].
For most adult trauma patients:
Scenario | Recommended Imaging |
Meets NEXUS/CCR low-risk criteria | No imaging |
Fails NEXUS/CCR | CT cervical spine |
Neurological deficit despite normal CT | MRI |
Suspected spinal cord injury | MRI |
Considering plain radiographs instead of CT | Don't |
When Can the Collar Come Off?
After spending several thousand words discussing cervical collars and how they are not benign, this is probably the question most readers actually care about.
Modern trauma guidelines increasingly emphasise early collar removal whenever it can be safely achieved.
"Cervical collars should be removed as soon as feasible after trauma"
The Awake Patient
In the awake, alert trauma patient, the message from EAST, ACS, NEXUS, and the Canadian C-Spine Rule is remarkably consistent.
- A cervical collar may be removed without imaging if the patient can be cleared clinically.
- If the patient fails clinical clearance, appropriate imaging is required. and a negative CT should prompt C-collar removal [2].
In the patient with penetrating trauma to the brain, immobilisation in a cervical collar is not necessary unless the examination suggests direct injury to the Cervical Spine [13].
The Awake Patient with Persistent Neck Pain but a Negative CT
This is one of the most controversial groups.
- Continue the cervical collar
- Remove the collar following a negative MRI
- Remove the collar following negative flexion-extension imaging
Personally, I find MRI the most reassuring option in this situation, although practice varies considerably between institutions.
The Obtunded Patient
This is where practice has changed the most over the last decade. Historically, obtunded patients remained immobilised for prolonged periods while clinicians waited for neurological improvement or additional imaging.
However, modern evidence suggests that a high-quality multidetector CT scan is extremely effective at excluding clinically significant unstable cervical spine injuries.
As a result, ACS currently recommends that a negative helical CT scan is sufficient to remove the cervical collar in an obtunded or unevaluable adult blunt trauma patient [2].
EAST takes a similar position, conditionally recommending collar removal after a negative high-quality CT scan alone [13]
It is important to remember that these recommendations are based on low-quality evidence and acknowledge a small but non-zero risk of missed injury.
If there is a C-Spine Injury
- If CT of the C-Spine demonstrates injury, obtain spine consultation.
- If there is a neurologic deficit attributable to a CS injury, obtain spine consultation and MRI.
Until specialist assessment and a definitive management plan have been completed, cervical spine motion restriction should be maintained.
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What Matters…
Ask these questions to decide if the C-Collar can be removed
1️⃣ Can the patient be clinically cleared using NEXUS or the Canadian C-Spine Rule?
Or an awake, alert trauma patient with:
- A normal neurological examination
- No midline cervical tenderness
- No distracting injury
- Full active range of motion of the neck
- No high-risk features
- The NEXUS Criteria and Canadian C-Spine Rule can be used in alert, stable patients following blunt trauma.
- ACS TQIP imaging guidelines stress that NEXUS and CCR criteria are not applicable for the pediatric patient or the older adult patient (55 years and older).
👉 Yes → Do not apply cervical collar. No imaging required
👉 No → Maintain spinal motion restriction and obtain CT imaging.
👉 No → Maintain spinal motion restriction and obtain CT imaging.
2️⃣ Is the CT normal?
- CT has a sensitivity approaching 100% for clinically significant cervical spine injuries.
- Slices of no greater than 3 mm are recommended.
👉 No → Obtain spine consultation. Continue spinal motion restriction.
👉 Yes → Proceed to Step 3.
👉 Yes → Proceed to Step 3.
3️⃣ Any other concerning features?
- Are there persistent neurological deficits or concern for spinal cord injury?
- Situations that should raise concern include:
- Motor weakness
- Sensory deficits
- Bowel or bladder dysfunction
- Unexplained neurological findings
- Subtle signs of a SCI, such as tachypnea.
- Neurogenic shock - shock with bradycardia
- Persistent neck pain despite a normal CT?
👉 Yes → Obtain MRI and spine consultation.
👉 Yes → Consider Collar removal or MRI or specialist review depending on local protocols.
👉 No → Consider Collar removal
A missed unstable cervical spine injury can be catastrophic. The goal is to identify the rare clinically significant injury while avoiding the harms of unnecessary prolonged immobilisation.
Guidelines
Clinical Decision Rules
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