Cervical Spine Fracture

Cervical spine fractures are potentially devastating injuries, and the priority throughout is to protect the spinal cord while the bony and ligamentous injury is evaluated and treated.

Two regions. The upper cervical spine (C1-C2) fails in specific patterns: the Jefferson, odontoid and hangman's fractures. The subaxial spine (C3-C7) is graded with the SLIC score, which guides treatment.

Clearance. Every trauma patient is assumed to have a cervical spine injury until it is cleared, and the collar stays on until then. NEXUS or the Canadian C-Spine Rule decide who can be cleared clinically.

Upper Cervical Spine (C0-C2)

The atlanto-occipital joint. C0-C1 allows 50% of cervical flexion-extension, and is stabilised by the tectorial membrane, the alar ligaments and the cruciate ligament.

The atlas. C1 is a ring with no vertebral body: anterior and posterior arches joined by the lateral masses, which articulate with the occipital condyles above and with C2 below.

The axis. The odontoid process (dens) projects up from C2 to articulate with the anterior arch of C1, where the transverse atlantal ligament (TAL) holds it. C2 also carries a large spinous process and the pars interarticularis.

The ligaments. The transverse atlantal ligament is the primary stabiliser of C1-C2 and prevents anterior translation of C1. The others:

• Alar ligaments - limit rotation
• Tectorial membrane - the continuation of the PLL to the occiput
• Cruciate ligament - the TAL plus its vertical bands

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Subaxial Cervical Spine (C3-C7)

The columns. The anterior column is the vertebral body and intervertebral disc. The posterior column is the pedicles, lateral masses, facet joints, laminae and spinous processes. The uncovertebral joints (joints of Luschka) are unique to the cervical spine.

The disco-ligamentous complex (DLC). One of the three SLIC domains, made up of:

• Anterior longitudinal ligament (ALL)
• Posterior longitudinal ligament (PLL)
• Intervertebral disc
• Facet joint capsules
• Ligamentum flavum
• Interspinous ligament

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Neural and vascular structures. The spinal cord terminates as the conus at L1-L2. Cervical roots exit above the vertebra of the same number, so the C6 root exits at C5-C6. The vertebral arteries run through the foramen transversarium from C6 to C1.

Cervical spine injury results from the interaction of the applied force vector with the quality of the host bone and ligament. The mechanism predicts the pattern and the risk to the neural structures.

Mechanism to pattern.

• Axial load - burst patterns: the Jefferson fracture of C1 and subaxial burst fractures with retropulsion into the canal
• Hyperextension - hangman's fracture (C2 pars), anterior tension-band (Type B3) injuries, and central cord syndrome in the spondylotic spine
• Flexion or flexion-distraction - wedge compression, facet subluxation or dislocation, posterior ligamentous (tension-band) failure
• Flexion-rotation - unilateral facet dislocation
• Distraction - atlanto-occipital dissociation and highly unstable distraction injuries

Primary and secondary cord injury. Primary injury is the immediate mechanical disruption at the moment of impact (contusion, laceration, compression), and it is irreversible. Secondary injury is an evolving cascade of oedema, ischaemia, excitotoxicity, free-radical damage and inflammation over hours to days. It is the therapeutic target of immobilisation, MAP augmentation and early decompression.

Host factors. Osteoporosis and pre-existing canal stenosis lower the force threshold for both fracture and cord injury, which explains the fall-related odontoid fractures and central cord patterns of the elderly. The ankylosed spine is the extreme case and has its own section below.

Primary Survey (ATLS)

Airway. Secure the airway with the cervical spine protected: in-line stabilisation for intubation, no neck extension, and awake fibreoptic intubation if time permits.

Breathing and circulation. Neurogenic shock is hypotension with bradycardia from loss of sympathetic tone. Distinguish it from hypovolaemic shock.

Disability. GCS, pupillary responses and the level of any spinal cord injury.

Neurological Examination

The examination follows ASIA/ISNCSCI: key muscles, key dermatomes, then an impairment grade.

Motor Assessment

Sensory Assessment

ASIA Impairment Scale

• A: Complete - no motor or sensory function in S4-S5
• B: Sensory incomplete - sensory but no motor function below the level, including S4-S5
• C: Motor incomplete - motor function preserved, majority of key muscles less than 3/5
• D: Motor incomplete - motor function preserved, majority ≥3/5
• E: Normal

Clinical Clearance

The Canadian C-Spine Rule asks three questions in order:

1. Any high-risk factor (age ≥65, dangerous mechanism, paraesthesias)? Image.
2. Any low-risk factor that allows range of motion to be assessed (simple rear-end MVC, ambulatory, delayed onset of pain)? Assess range of motion.
3. Can the patient actively rotate the neck 45° each way? No imaging is needed.

NEXUS clears the spine clinically only when all five criteria are present.

CT. The first-line study for bony injury, indicated in all significant trauma; plain radiographs are now less commonly used. Scan from the skull base to T1, including the C7-T1 junction, and assess alignment, fracture pattern and canal compromise.

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MRI. Shows cord oedema or contusion, disc herniation and disruption of the ligaments and disc as bright T2 signal. For an acute injury it is obtained within 24-72 hours, and the indications are:

• Neurological deficit
• Obtunded patient who cannot be cleared clinically; whether MRI adds anything after a normal CT is debated (see the obtunded patient, below)
• Suspected ligamentous (DLC) injury
• Suspected disc herniation

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CT angiography. Screens for vertebral artery injury (dissection, occlusion). Indications:

• Fracture through the foramen transversarium
• Facet subluxation or dislocation
• High-energy mechanism

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What to look for.

• Jefferson - lateral mass overhang on the open-mouth (odontoid) view
• Odontoid - where the fracture line lies, on sagittal CT
• Hangman's - bilateral C2 pars fractures
• Facet dislocation - perched or locked facets on sagittal CT
• Canal compromise - measured for surgical planning

Blood tests. FBC and a coagulation profile before surgery, group and screen; consider an arterial blood gas if breathing is compromised.

The key task is distinguishing an unstable bony or ligamentous injury (needing immobilisation and often surgery) from mimics that change management. Neck pain after trauma is never assumed benign until the spine is cleared.

Why it behaves like a long-bone fracture. A spine ankylosed by ankylosing spondylitis or DISH is a long, rigid, brittle, often osteoporotic lever with no segmental motion to absorb energy. A trivial mechanism, often hyperextension (a simple fall, even in a collar), produces a transverse, three-column, unstable "carrot-stick" fracture, frequently through a fused disc space or the fusion mass. These are the most unstable cervical injuries, and they are notoriously occult on plain films against the abnormal background.

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Image the whole spine. Non-contiguous fractures and occult injuries are common, so the standard is a low threshold for CT of the entire spine, with MRI for the high epidural haematoma risk and for neurology.

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Do not correct the deformity. Immobilise and transport the patient in the pre-injury position of deformity, the "position of comfort", using pillows or blocks to support the habitual posture. Forcing a fixed kyphotic ankylosed neck into a standard flat collar or neutral alignment can distract the fracture and cause catastrophic cord injury.

Treatment. These fractures usually need surgery, and long fixation. Conservative management (halo or collar) has high failure, malunion and mortality, and most are treated with long-segment posterior instrumented fixation, several levels above and below, to control the long lever arm, sometimes combined anterior-posterior. Epidural haematoma is common and can cause delayed deterioration, so a high index of suspicion and early MRI are essential.

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Expect high morbidity and mortality. Delayed or missed diagnosis is frequent, because the injury hides on plain films and the mechanism seems trivial. Neurological deficit and epidural haematoma are common, and mortality is high: the ankylosed-spine fracture is one of the most dangerous injuries in spinal trauma.

Why the clinical rules do not apply. NEXUS requires normal alertness, no intoxication and no distracting injury, and the Canadian rule requires an alert (GCS 15), stable patient who can be asked about pain and can rotate the neck. The obtunded, intubated, head-injured, intoxicated or distracted patient meets none of these, so clinical clearance is impossible and the whole question is how to clear, or not clear, the spine radiologically.

A high-quality negative CT is the pivotal test. Modern multidetector CT from occiput to T1 has very high sensitivity and negative predictive value for unstable bony injury, and its negative predictive value for the injuries that actually need intervention approaches ~99%. The core debate is whether a technically adequate, expertly read negative CT is sufficient to clear the collar in the obtunded but neurologically normal patient, or whether MRI is still required.

The role, and limits, of MRI. MRI is more sensitive for purely ligamentous and disco-ligamentous injury, and is mandatory with any neurological deficit or a suspicious CT. In the obtunded patient with a normal CT, though, it frequently shows clinically insignificant findings that prolong immobilisation without changing management, and it carries the risks and logistics of transferring a critically ill patient. Contemporary evidence and many guidelines therefore support collar removal on a normal high-quality CT alone in this group, with MRI reserved for an abnormal CT, a focal deficit or persistent concern, though practice still varies.

The cost of leaving the collar on. "Just keep the collar" is not benign. Prolonged rigid-collar use causes pressure ulcers, raised intracranial pressure, impaired airway and central-line access, aspiration and delirium in the ICU patient, so an indefinite collar is itself a harm, to be weighed against the small residual risk of an occult unstable ligamentous injury after a normal CT.

Neurological. Progression of the cord injury is secondary injury, and the measures that limit it are described under Pathophysiology. Iatrogenic injury comes from screw malposition (into the cord, a nerve root or the vertebral artery), excessive retraction and decompression injury.

Anterior approach.

• Dysphagia - 2-60% (usually transient)
• Recurrent laryngeal nerve palsy - 2-11% (hoarseness)
• Oesophageal injury - rare but serious
• Vascular injury - carotid, vertebral artery

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Posterior approach.

• Vertebral artery injury - 0.1-4% (C2 pedicle screws highest risk)
• C5 palsy - 2-16% (deltoid weakness)
• Wound infection - 1-3%

Hardware. Screw pull-out, rod fracture, cage subsidence and plate migration.

Nonunion (pseudarthrosis). Smoking, multilevel fusion and osteoporosis are the risk factors, and nonunion is higher in upper cervical injuries.

Adjacent segment disease. Stress on the adjacent levels increases; the disease accrues over years and may require extension of the fusion.

Medical.

• DVT/PE (high risk in SCI)
• Pneumonia (especially high cervical SCI)
• Pressure ulcers
• Autonomic dysreflexia (injuries above T6)

Neurological recovery. A complete injury (ASIA A) carries a poor prognosis for significant motor recovery, and rehabilitation focuses on adaptation and activities of daily living. Incomplete injury (ASIA B-D) has a better prognosis, improved further by early decompression (STASCIS), and central cord syndrome characteristically recovers the legs before the hands. Root injuries have a good prognosis, with meaningful improvement in the majority.

By fracture. Type II odontoid fractures have a high nonunion rate in a halo vest (see the evidence) against high fusion rates with surgery. Jefferson fractures do well in a collar if the TAL is intact, and otherwise after fusion; Types I-II hangman's fractures generally do excellently. SLIC-guided treatment of subaxial injuries with posterior instrumentation achieves high fusion rates.

Long term. Chronic neck pain and reduced range of motion, especially after fusion, are common.

Mortality. Highest in complete SCI, in elderly odontoid fractures (high regardless of treatment), and when upper cervical injury is associated with head injury.

Global Epidemiology

• Bimodal age distribution: a young-male peak (high-energy road traffic and sports/diving trauma) and an older peak (low-energy falls, often on osteoporotic or ankylosed spines)
• Cervical spine is the most common level of traumatic spinal cord injury, and the proportion of geriatric, fall-related injury is rising worldwide as populations age
• Odontoid fractures are the single most common cervical fracture in patients over 70, frequently from a simple ground-level fall
• Mechanism shift by setting: high-income/ageing populations are dominated by elderly falls; younger road-traffic and diving injuries predominate in many low- and middle-income settings

Side-by-Side Guidelines

Decision Rules for Imaging

• NEXUS and the Canadian C-Spine Rule are the two validated tools for clinical clearance in alert, stable patients; the Canadian rule is more specific (fewer images) while both have very high sensitivity
• CT is first-line whenever imaging is indicated; MRI is reserved for neurological deficit, obtunded patients, or suspected disco-ligamentous injury

High- vs Limited-Resource Practice Variation

• Well-resourced systems: rapid CT and MRI access, dedicated spinal-injury units, early (within 24h) decompression, and structured multidisciplinary rehabilitation
• Limited-resource settings: greater reliance on plain radiographs and clinical decision rules, prolonged collar/halo immobilisation where surgical capacity is constrained, and longer pre-hospital times that increase the importance of meticulous immobilisation and transfer
• Ankylosing spinal disorders (ankylosing spondylitis, DISH) demand a low threshold for CT (often the whole spine) everywhere, as fractures are frequently occult, highly unstable, and easily missed on plain films

MRI before closed reduction of a facet dislocation. Up to 40-50% of facet dislocations harbour a traumatic disc herniation. Whether to obtain MRI first, to avoid pushing disc into the canal, or to reduce immediately in an awake patient, to decompress the cord sooner, remains debated. Many centres reduce awake when MRI would cause significant delay and the patient is deteriorating.

The elderly Type II odontoid fracture. Surgery improves union rates but carries operative risk, while non-operative care accepts a high rate of stable fibrous nonunion. Given the mortality noted under Outcomes, management is individualised by physiological reserve and patient goals rather than by age alone.

Collar or halo for stable upper cervical injuries. Halo immobilisation is poorly tolerated in the elderly (pneumonia, pressure sores), and many now favour a rigid collar or early surgery over prolonged halo use.