EM · Cervical spine injury & clearance
Cervical spine injury and clearance
The cervical spine injury from the mechanism to the immobilisation, the NEXUS and the Canadian C-Spine Rule for the clinical clearance, the CT as the standard imaging for the adult, the MRI for the ligamentous and the cord injury, the injury patterns (the flexion, the extension, the vertical compression), the cord syndromes, and the clearance of the collar.
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Red flags
The cervical spine injury is the injury that cannot be missed — a missed unstable fracture or a ligamentous injury with the cord damage is the preventable catastrophe of the trauma — and yet the clearance of the cervical spine in the alert, the stable patient is also one of the commonest source of the unnecessary imaging. The Fellowship candidate must know the immobilisation, the two clinical decision rules (the NEXUS and the Canadian C-Spine Rule) that guide the imaging, the injury patterns and the cord syndromes, and the principles of the clearance in the special populations.[1][1]
Immobilisation
The trauma patient is assumed to have a cervical spine injury until it is cleared, and the immobilisation is applied from the scene. The manual in-line stabilisation is maintained during the airway manoeuvres, and the patient is placed in the hard collar, the head blocks and the tape (the three-point immobilisation). The spine board is for the extrication and the short transfer only — it is removed as soon as possible because it causes the pressure, the discomfort and the heat loss. The log-roll is performed for the transfer, the examination and the removal of the board. The prolonged immobilisation causes the pressure sores, the deep-vein thrombosis, the aspiration risk and the raised intracranial pressure (the collar compresses the jugular veins), so the collar is removed as early as safely possible.[1]
The NEXUS criteria
The NEXUS criteria are the five clinical criteria that, if all met, allow the cervical spine to be cleared without the imaging. The criteria are: (1) no midline cervical tenderness, (2) no focal neurological deficit, (3) a normal level of alertness (the patient is fully awake and oriented, not intoxicated), (4) no intoxication (no alcohol, no drugs, no metabolic), and (5) no painful distracting injury (no long-bone fracture, no large laceration, no thermal injury that would distract from the neck pain). The NEXUS criteria have a high sensitivity (they miss very few injuries) but a lower specificity (many patients who meet none of the criteria still have no injury, and so they are imaged unnecessarily), and they are less reliable in the elderly.[1][1]
The Canadian C-Spine Rule
The Canadian C-Spine Rule is the alternative clinical decision rule with a higher specificity, and it applies to the alert (GCS 15), the stable trauma patient in whom the cervical spine is a concern. The rule first identifies the high-risk factors (the age 65 or above, the dangerous mechanism, the limb paraesthesia) that mandate the imaging regardless. If none of the high-risk factors are present, the low-risk factors are assessed (the simple rear-end motor-vehicle collision, the sitting position in the emergency department, the ambulatory at any time, the delayed onset of the neck pain, the absence of the midline tenderness) that allow the safe assessment of the neck rotation. If the patient can rotate the neck 45 degrees to the left and the right, the cervical spine is cleared clinically.[1]
The imaging
The computed tomography is the standard imaging for the adult trauma patient at risk of a cervical spine injury. The plain radiographs (the lateral, the AP and the odontoid views) are no longer recommended for the adult clearance, because their sensitivity is unacceptably low (the C7-T1 junction is missed on the lateral view in a significant minority). The CT has a near-100 per cent sensitivity for the bony injury and is the first-line imaging for the patient who does not meet the clinical clearance criteria. The MRI is the imaging of the ligamentous injury, the cord injury and the disc injury — it is indicated for the patient with the neurological deficit, the highly suspicious mechanism with a normal CT, and the obtunded or the intubated patient who cannot be cleared clinically (though the early MRI clearance of the obtunded patient is an area of the ongoing debate).[1][1]
The injury patterns
The mechanism determines the pattern. The flexion produces the wedge compression fracture (the anterior vertebral body height loss), the bilateral facet dislocation (the unstable injury with the cord compromise in the majority), and the flexion teardrop fracture (the most unstable of the cervical injuries). The extension produces the hangman fracture (the bilateral C2 pars fracture — the traumatic spondylolisthesis of the axis) and the hyperextension dislocation. The vertical compression produces the Jefferson fracture (the burst fracture of the C1 ring from the axial load) and the burst fracture of the sub-axial vertebral body (the retropulsed fragment compromises the canal). The rotation produces the unilateral facet dislocation (the stable or the unstable, depending on the capsular disruption).[1]
The cord syndromes
The spinal cord injury presents with the neurological deficit below the level of the injury, and the pattern identifies the syndrome. The complete cord injury (the total loss of the motor and the sensory function below the level) carries the worst prognosis. The anterior cord syndrome (the motor and the pain-and-temperature loss with the preserved proprioception) suggests the anterior spinal artery compromise and has a poor recovery. The central cord syndrome (the greater upper-limb than lower-limb weakness, from the hyperextension in the older patient with the canal stenosis) has the best prognosis of the incomplete syndromes. The Brown-Sequard syndrome (the ipsilateral motor and proprioception loss with the contralateral pain-and-temperature loss, from the hemisection) has a good prognosis. The cauda equina syndrome (the bilateral leg weakness, the saddle anaesthesia, the sphincter disturbance) is the peripheral nerve injury that may recover.[1][1]
The clearance
The cervical spine is cleared when the clinical criteria (the NEXUS or the Canadian C-Spine Rule) are met in the alert, the unintoxicated patient, or when the imaging (the CT for the bony injury, the MRI for the ligamentous and the cord injury) is negative. The obtunded or the intubated patient cannot be cleared clinically — the collar is maintained until the MRI excludes the ligamentous injury, or the expert review of the CT with the dynamic fluoroscopy or the clinical assessment at the extubation clears it. The paediatric cervical spine (the ligamentous laxity, the SCIWORA — the spinal cord injury without the radiological abnormality) has its own clearance pathway, and the NEXUS criteria are less reliable in the child.[1]
Exam-exhaustive deep dive — the clearance, the imaging and the cord
The Fellowship candidate is examined on the decision-making: which rule to apply, which patient can be cleared clinically, which imaging to obtain, and how to manage the cord injury. The sections below set out each of these at the depth the examiner expects, with the two clinical decision rules compared head-to-head, the imaging strategy in the alert and the obtunded patient, the clearance pathways, the cord syndromes in detail, and the principles of the spinal cord injury management.[1][1]
The two clinical decision rules compared — NEXUS versus the Canadian C-Spine Rule
The NEXUS criteria and the Canadian C-Spine Rule are the two validated clinical decision rules that allow the safe clearance of the cervical spine without the imaging in the alert, the stable trauma patient. They differ in their structure, their test performance and their applicability, and the Fellowship candidate is expected to know both and to choose between them. The NEXUS rule is a set of five absence criteria (all must be absent); the Canadian rule is a sequence of high-risk factors (any present mandates the imaging) followed by the low-risk factors (any present allows the safe assessment of the rotation).[2][3]
| Feature | NEXUS low-risk criteria | Canadian C-Spine Rule |
|---|---|---|
| Structure | Five absence criteria — ALL must be met to clear | Three high-risk (mandate imaging) + five low-risk (allow the rotation test) |
| Eligible population | The alert, stable blunt-trauma patient with the c-spine concern | Alert (GCS 15), stable, age > 16, blunt trauma, c-spine a concern |
| Age threshold | None stated (less reliable in the elderly) | Age > 65 is a HIGH-RISK factor — image regardless |
| Mechanism of injury | Not explicitly considered | The dangerous MANDATES imaging; the simple rear-end is a low-risk factor |
| The decisive test | Meet all five criteria = clear clinically | Able to rotate the neck 45° left AND right = clear clinically |
| Sensitivity (derivation) | 99.6% (misses < 1%) | 100% (missed none in the derivation) |
| Specificity (derivation) | Low — about 13% (over-scans) | Higher — about 43% (fewer unnecessary scans) |
| Head-to-head (Stiell 2003) | Sensitivity 90.7%, specificity 36.4% | Sensitivity 99.4%, specificity 45.1% |
| The classic weakness | The subjective intoxication and the distracting-injury criteria; the elderly | Cannot be applied to the obtunded, the intubated or the unstable patient |
| Where it is taught | The North American (ATLS, ABEM) standard | The Australasian and the UK (ACEM, RCEM) preference |
The imaging strategy — the CT, the MRI and the obsolete plain film
The imaging of the cervical spine in the trauma is the CT first, the MRI for the specific indication, and the plain radiograph confined to history. The choice is governed by the clinical status (alert vs obtunded) and the presence of the neurological deficit.[1][1]
| Modality | Sensitivity / role | Indication | The limitation |
|---|---|---|---|
| Plain radiograph (3-view: lateral, AP, odontoid) | 36 to 60% for the bony injury; misses the C7-T1 junction and the occipito-cervical junction | Obsolete for the adult clearance; may be the only option in the resource-limited or the paediatric setting | The low sensitivity; the C7-T1 is missed on the inadequate lateral in up to a quarter |
| CT cervical spine (thin-cut, sagittal and coronal reformats) | ~99 to 100% for the bony injury | First-line for any adult who does not meet the clinical clearance criteria; the high-risk, the obtunded, the focal deficit | The radiation; the limited sensitivity for the purely ligamentous injury (a normal CT does not exclude the ligamentous injury in the obtunded) |
| MRI cervical spine | The gold standard for the cord, the ligament, the disc and the haematoma | The neurological deficit, the highly suspicious mechanism with the normal CT, the clearance of the obtunded (selectively) | The time, the logistics, the instability of the critically ill patient in the magnet, the motion and the swallow artefact; the over-diagnosis of the incidental degenerative signal |
| Dynamic fluoroscopy | Assesses the ligamentous stability in real time | The historical clearance of the obtunded with the normal CT; largely replaced by the MRI or the delayed clinical clearance | The resource-intensive, the inter-observer variability, the sensitivity lower than the MRI; not the modern default |
The clearance pathways — the alert, the obtunded and the special populations
The clearance of the cervical spine follows one of three pathways, determined by the alertness, the intoxication and the neurological status of the patient. The Fellowship candidate must be able to recite the pathway for each.[1]
The clearance of the awake, alert and sober patient — the clinical pathway
Confirm the eligibility
The patient is alert (GCS 15), unintoxicated, haemodynamically stable, and the cervical spine is a clinical concern. The distracting injury, the intoxication and the depressed conscious state each exclude the clinical pathway and mandate the CT.
Apply the Canadian C-Spine Rule (or the NEXUS criteria)
Assess the three high-risk factors (age 65 or above, the dangerous mechanism, the limb paraesthesia). Any present mandates the CT. If none present, assess the five low-risk factors (the simple rear-end, the sitting position, the ambulatory, the delayed pain, the no midline tenderness). At least one present allows the rotation test.
The 45-degree rotation test
Ask the patient to rotate the neck 45 degrees to the left AND 45 degrees to the right. The ability to do both pain-free clears the cervical spine clinically — the collar is removed, the patient is discharged or managed for the other injuries, and no imaging is obtained. Inability to rotate, or the high-risk factor, mandates the CT.
Document and remove the collar
The clearance is documented in the notes with the explicit statement of the rule applied and the criteria met. The collar is removed, the neck is examined, and the patient is advised the neck may remain stiff for the days (the soft-tissue injury) with the return precautions for the neurological symptoms.
The clearance of the obtunded or the intubated patient — the imaging pathway
Maintain the immobilisation
The collar, the head blocks and the tape remain in place. The patient cannot be cleared clinically — the alertness and the intoxication criteria of NEXUS fail, and the Canadian rule cannot be applied. The collar is maintained until the imaging or the delayed clinical assessment clears the spine.
Obtain the high-quality CT
The thin-cut CT of the cervical spine from the occiput to the T1-T2 junction, with the sagittal and the coronal reformats, is obtained as part of the trauma pan-scan. A normal CT clears the bony injury.
The CT-only default or the selective MRI
In the modern practice, a normal CT in the obtunded patient is sufficient for the removal of the collar in many centres (the CT-only default). The MRI is obtained for the focal neurological deficit, the highly suspicious mechanism, the abnormal CT, or the local protocol that mandates the MRI. The routine MRI of every normal-CT obtunded patient is no longer universal.
The delayed clinical clearance at the extubation
If the collar is maintained (the CT-only protocol not applied), the cervical spine is cleared at the extubation by the alert clinical assessment (the NEXUS or the Canadian rule) once the patient is awake, sober and able to cooperate. The dynamic flexion-extension fluoroscopy or the MRI is the alternative if the clinical assessment is equivocal.
The manual in-line stabilisation and the intubation — MILS for the rapid sequence
The trauma patient with the suspected cervical spine injury who requires the intubation is intubated with the manual in-line stabilisation (MILS) — the collar is opened (or removed), the second operator holds the head in the neutral in-line position without the traction, and the first operator performs the rapid sequence induction. The collar is NOT left on for the intubation — the rigid collar flexes the neck and obstructs the laryngoscopy, and it is replaced after the tube is secured.[1]
The rapid sequence intubation with the manual in-line stabilisation (MILS)
Prepare and pre-oxygenase
The standard RSI preparation — the equipment check, the suction, the waveform capnography, the four meters of head-end space. The patient is pre-oxygenated with the 100 per cent oxygen for the 3 minutes (or the 8 vital-capacity breaths).
Position the MILS operator
The second operator stands or kneels at the head of the bed, grasps the mastoid processes and the occiput with the fingertips, and holds the head in the neutral in-line position WITHOUT the traction. The traction is avoided — it can distract the fracture and injure the cord.
Open the front of the collar
The front of the rigid collar is undone and folded away (or the collar is removed) to allow the jaw thrust, the mouth opening and the laryngoscopy. The MILS operator maintains the stabilisation from below the head. The collar is never left on during the laryngoscopy — it obstructs the view.
Induce, paralyse and intubate
The standard RSI drugs (the induction agent and the suxamethonium or the rocuronium). The first operator performs the laryngoscopy with the minimal neck movement — the MILS operator counteracts any flexion or extension. The video laryngoscopy is preferred (the better view with the less neck movement). The tube is confirmed with the waveform capnography.
Reapply the collar and secure
Once the tube is confirmed, the collar is reapplied, the patient is secured, and the spine board is removed (the log-roll) as soon as possible. The MILS is maintained for any subsequent repositioning until the cervical spine is cleared.
The cord syndromes in detail — the pattern identifies the level and the prognosis
The spinal cord injury presents with the neurological deficit below the level of the lesion, and the pattern of the deficit identifies the syndrome, the mechanism and the prognosis. The complete injury carries the worst prognosis; the incomplete injuries differ in their territory and their recovery, and the Fellowship candidate must be able to recognise each at the bedside.[1][1]
| Syndrome | Mechanism / territory | Motor | Sensory | Bladder / bowel | Prognosis |
|---|---|---|---|---|---|
| Complete cord | The total transection (the severe fracture-dislocation, the burst) | Total loss below the level | Total loss below the level | Retention (the areflexia acutely) | Worst — the least recovery |
| Central cord | The hyperextension in the older patient with the canal stenosis | The arms weaker than the legs (the man-in-a-barrel) | Variable; often the upper-limb dyseaesthesia | Retention common | The best of the incomplete — the legs recover first, the hands last |
| Anterior cord | The anterior spinal artery compromise (the flexion, the retropulsed fragment, the dissection) | The bilateral motor loss (the LMN at the level, the UMN below) | The loss of the pain and the temperature; the PROPRIOCEPTION and the vibration PRESERVED | Retention | Poor — the motor recovery is limited |
| Brown-Sequard | The hemisection (the penetrating, the unilateral facet fracture) | The ipsilateral motor loss (the UMN below) | The ipsilateral proprioception and vibration loss; the CONTRALATERAL pain and temperature loss (1-2 levels below) | Often spared | The best recovery of the incomplete syndromes |
| Posterior cord | The rare — the posterior column injury | Preserved | The isolated loss of the proprioception and the vibration | Usually spared | Variable |
| Conus medullaris | The T12-L1 injury (the junction of the cord and the roots) | The mixed UMN and LMN; the symmetric | The saddle anaesthesia | The early and the severe — the mixed | Guarded |
| Cauda equina | The injury of the lumbosacral nerve roots (the peripheral nerve) | The LMN; the asymmetric; the areflexia | The saddle anaesthesia; the asymmetric | Retention, the lax sphincter | The peripheral nerve — may recover |
The management of the spinal cord injury — the perfusion, the decompression and the collar
The management of the acute spinal cord injury in the emergency department is the maintenance of the spinal perfusion, the early identification of the operable compression, the prevention of the secondary injury, and the neurosurgical referral. The high-dose methylprednisolone (the NASCIS protocol) is NOT recommended in the modern practice.[1][1]
The emergency-department management of the acute spinal cord injury
Resuscitate and immobilise
The ATLS primary survey with the c-spine immobilisation maintained. The airway is secured with the MILS-RSI if the respiratory failure or the conscious-state depression is present (the high cord injury causes the diaphragmatic and the intercostal paralysis). The oxygen is given to maintain the saturation above 94 per cent.
Maintain the spinal cord perfusion
The mean arterial pressure is maintained at 85 to 90 mmHg for the first 7 days — the hypotension (the neurogenic shock, the haemorrhagic shock) is the preventable cause of the secondary cord injury. The noradrenaline is the vasopressor of choice (the alpha and the beta, the reliable venous return), and the fluid is given cautiously (the SIADH and the over-resuscitation risk).
Obtain the MRI and refer to the neurosurgery
The MRI defines the cord, the disc, the ligament and the haematoma. The urgent decompression (within 24 hours) is indicated for the deteriorating neurological deficit and the operable compression — the timing of the surgery (early vs late) is the subject of the STASCIS and the AOSpine evidence, and the early decompression within 24 hours of the incomplete injury is the modern standard. The neurosurgical referral is made at the earliest.
Prevent the secondary injury and the complications
The high-dose methylprednisolone is NOT recommended (the AOSpine 2017 guidance — the harm exceeds the benefit). The VTE prophylaxis (the early chemical, within 72 hours, balanced against the risk), the pressure-area care, the gastric and the DVT prophylaxis, and the early removal of the collar once cleared.
NEXUS (Hoffman, NEJM 2000) — the five clinical criteria to rule out the cervical spine injury
Design
Prospective, multicentre, observational — 34,069 blunt-trauma patients across 21 US centres, the derivation of the five-criteria rule
Intervention
The five NEXUS criteria (no midline tenderness, no focal deficit, alert, no intoxication, no distracting injury) applied to decide the radiography
Primary result
Sensitivity 99.6% (95% CI 98.0-99.9) for the clinically important injury; 8 of 818 injuries missed (only 2 clinically significant); specificity 12.9%
Bottom line
The NEXUS rule is the safe, sensitive rule that misses almost nothing — at the cost of the low specificity and the over-scanning. The conservative rule, the North American standard.
Canadian C-Spine Rule (Stiell, JAMA 2001) — the three high-risk and five low-risk factors
Design
Prospective, multicentre, derivation study — 8,924 alert, stable trauma patients across 10 Canadian centres
Intervention
The Canadian C-Spine Rule — the three high-risk factors (age 65 or above, dangerous mechanism, limb paraesthesia) then the five low-risk factors and the 45-degree rotation test
Primary result
Sensitivity 100% (95% CI 98-100); specificity 42.5%; the radiography rate would have fallen by 15.5 per cent
Bottom line
The Canadian rule is the higher-specificity alternative to NEXUS — it misses nothing and saves more scans. The preferred rule in the Australasian and the UK practice.
Stiell NEJM 2003 — the Canadian C-Spine Rule versus the NEXUS criteria, head-to-head
Design
Prospective cohort — 8,283 alert and stable trauma patients in 9 Canadian centres, both rules applied and compared against the imaging and the follow-up
Key result
The Canadian C-Spine Rule: sensitivity 99.4%, specificity 45.1%. The NEXUS criteria: sensitivity 90.7%, specificity 36.4%. The Canadian rule missed 1 important injury; the NEXUS missed 16
Clinical impact
The Canadian rule would have ordered the imaging in 55.9 per cent; the NEXUS in 66.6 per cent. The Canadian rule is the more accurate rule on both axes
Bottom line
In the direct comparison, the Canadian C-Spine Rule outperforms the NEXUS criteria — fewer scans AND fewer misses. The head-to-head the examiner cites.
Common pitfalls
The recurring errors are: not immobilising the cervical spine from the scene; clearing the cervical spine without meeting all the NEXUS criteria (especially the intoxication and the distracting injury criteria); using the plain radiographs instead of the CT for the adult clearance; missing the ligamentous injury in the obtunded patient with a normal CT; not considering the cord syndrome in the patient with the focal deficit; and the prolonged immobilisation causing the pressure, the DVT and the raised intracranial pressure. [1]
SAQ — Clinical clearance of the cervical spine in the alert trauma patient
10 minutes · 10 marks
A 45-year-old woman is brought to the emergency department after a rear-end motor-vehicle collision at 60 km per hour. She was the restrained front-seat passenger, she was ambulatory at the scene, and she now complains of mild midline neck pain that began two hours after the collision. She is fully alert (GCS 15), unintoxicated, haemodynamically stable, with no focal neurological deficit and no limb paraesthesia.
SAQ — The obtunded trauma patient and the central cord syndrome
10 minutes · 10 marks
A 72-year-old man is intubated in the emergency department after a forward fall onto his forehead. He is sedated and cannot be examined. The CT of the cervical spine shows the degenerative canal stenosis but no fracture. On day 2, once the sedation is lifted, he is found to have the striking weakness of both arms with the relatively preserved leg strength, and the preserved joint position sense.
Red flags
The following features identify the cervical spine at risk or the clearance that is incomplete, in which the collar is maintained and the imaging is obtained: [1]
[1]References
- [1]Touger M, Gennis P, Nathanson N, et al. Validity of a decision rule to reduce cervical spine radiography in elderly patients with blunt trauma Ann Emerg Med, 2002.PMID 12192352
- [2]Hoffman JR, Mower WR, Wolfson AB, Todd KH, Zucker MI. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. National Emergency X-Radiography Utilization Study Group N Engl J Med, 2000.PMID 10891516
- [3]Stiell IG, Wells GA, Vandemheen KL, et al. The Canadian C-spine rule for radiography in alert and stable trauma patients JAMA, 2001.PMID 11597285
- [4]Stiell IG, Clement CM, McKnight RD, et al. The Canadian C-spine rule versus the NEXUS low-risk criteria in patients with trauma N Engl J Med, 2003.PMID 14695411