Approach
The diagnostic process is aimed at excluding the possibility of an unstable cervical spine injury that could potentially cause spinal cord compression and neurological compromise. In any trauma setting, until this possibility has been definitively excluded, neck immobilization with a rigid collar is mandatory. Diagnosis involves a combination of history, physical findings, and, when required, imaging studies.
Key considerations include:
Determining which patients need cervical spine imaging after trauma
Deciding whether the most appropriate imaging is by dynamic cervical spine x-rays (flexion-extension views), computed tomography (CT), or magnetic resonance imaging (MRI)
Excluding dynamic or ligamentous instability in patients who are comatose or have reduced consciousness level.
Once an unstable cervical spine injury has been excluded, the vast majority of remnant cervical injuries are secondary to soft-tissue damage and typically do not require significant additional investigation or treatment.
Cervical spinal motion restriction (SMR)
For various reasons, not all patients are assessed in the pre-hospital environment and patients may walk in to the emergency department complaining of neck pain following a fall or other trauma without neck or spinal precautions in place. Although the majority may ultimately turn out not to have significant injury, the clinician must remain alert to the possibility that some may have an unstable injury and act accordingly.
Cervical spine precautions (a correctly fitting hard collar, head blocks, and spinal board) serve to restrict spinal motion, protect, and assist with the transportation and handling of patients with potential spinal injury. When SMR is indicated in adults, it should be applied to the entire spine due to the risk of noncontiguous injuries. A critical component of SMR is the application of an appropriately-sized cervical collar.[14] The head, neck, and torso should be kept in alignment by placing the patient on a long backboard, a scoop stretcher, a vacuum mattress, or an ambulance cot.[14][25] A rigid backboard should be used for transport only and every effort should be made to remove the board as soon as possible.[26]
If there is evidence of any of the following in a patient, after an incident thought to be compatible with a possible cervical spine injury, the clinician should apply SMR including a rigid cervical collar:[14][25]
Acutely altered level of consciousness (Glasgow Coma Scale [GCS] <15, evidence of intoxication) [ Glasgow Coma Scale Opens in new window ]
Focal neurological signs and/or symptoms (e.g., subjective limb weakness, numbness, tingling, or dysesthesia)
Anatomic deformity of the spine
Distracting circumstances or injury (e.g., long bone fracture, degloving, or crush injuries, large burns, emotional distress, communication barrier, etc) or any similar injury that impairs the patient's ability to contribute to a reliable examination.
These patients often require reassurance that this is a precautionary (but important) action and that the measures will be removed as soon as serious injury is excluded. If none of these features is present, it is safe to omit cervical spine precautions and proceed to the later stages of assessment.
Cervical spine imaging is not necessary, and the cervical collar may be removed, if the following conditions are met in an adult trauma patient:[14]
Awake and alert (GCS = 15)
Normal neurological exam
No high-risk injury mechanism
No neck tenderness
Free range of cervical motion.
The remainder of the spine must also be similarly cleared before SMR is removed. The term "SMR" is recommended instead of "immobilization" because current techniques limit or reduce undesired motion of the spine, but they do not provide true spinal immobilization.[14][25]
Factors predictive of severe cervical spine injury
The mode and mechanism of injury (e.g., motor vehicle collision, fall, diving injury, hyperflexion-extension, axial loading) should be determined to help assess the likelihood of significant injury. Higher-energy mechanisms of injury, as well as those associated with head or face strikes, carry a higher risk of an unstable cervical spine injury.
History
In a timely, safe, and systematic manner, the clinician must assess and examine the patient so that a decision can be made as to whether the cervical precautions can be safely removed.
Assessment and diagnosis should follow Advanced Trauma Life Support (ATLS) protocols, with preliminary evaluation and management of airway, breathing, and circulation.[14][26] Once the patient is stable with regard to these vital aspects, the cervical spine can be assessed.
History-taking is conducted as part of the secondary survey. Specific questioning should be made regarding presence of neck pain and radiation into the upper extremities, shoulder girdle, or back, and presence of neurological dysfunction, such as subjective limb weakness or paralysis, numbness, tingling, or dysesthesia in limbs or trunk. However, absence of such symptoms with a distracting injury may be misleading.[14]
The mode and mechanism of injury (e.g., motor vehicle collision, fall, diving injury, hyperflexion-extension, axial loading) should be determined to help assess the likelihood of significant injury.[10] Higher-energy mechanisms of injury, as well as those associated with head or face strikes, carry a higher risk of an unstable cervical spine injury.
If a high cervical spinal cord injury compromises phrenic nerve function, or if associated neck soft-tissue injury occurs, patients may complain of subjective difficulty with breathing or shortness of breath.
With motor vehicle collisions, the basic circumstances of the event should be elicited, including the patient's position in the vehicle, use of restraints, airbag deployment, and the nature of the crash (e.g., rear impact, frontal impact, rollover).
Features of the past medical history that may increase the likelihood of injury include previous neck injury, osteopenia or osteoporosis, rheumatoid arthritis, ankylosing spondylitis, and malignancies with a tendency for bony metastasis (e.g. prostate, breast, bowel). Previous strokes may account for weakness. Medication history may give clues to potentially important comorbidities. Patients on anticoagulants (e.g., low molecular weight heparin, warfarin) may require anticoagulant reversal if significant soft-tissue or bony injury is discovered. Previous history of spine trauma and presence of spinal implants may impact surgical and radiologic decision-making.
Physical exam
The primary survey should focus on hemorrhage control, airway, breathing, circulation, disability, and exposure. Cervical and thoracolumbar spinal motion restriction should be maintained throughout this phase, until the spine is further evaluated during the secondary survey.[14] Vital signs should be measured. A combination of hypotension and bradycardia in the setting of potential spinal cord injury may be indicative of neurogenic shock.
Level of consciousness should be formally assessed using the Glasgow Coma Scale (GCS). Impairment of consciousness might impact reliability of history and physical exam findings.[14]
[ Glasgow Coma Scale Opens in new window ]
The primary survey should identify any lateralizing signs by conducting a rapid assessment of motor function and reflexes in the extremities. Depressed level of consciousness, extremity or pelvic fractures, burns or other injuries, such as to the brachial plexus may affect the results of sensory or motor deficit evaluation.[14] Signs observed during the primary survey suggestive of a spinal cord injury include absence of equal movement in the upper and/or lower extremities that may be combined with a gross sensory deficit.[14] Loss of bowel and bladder function (urinary retention or urinary/fecal incontinence) and/or priapism in males can suggest acute spinal cord injury and need to be excluded.[14][27]
The secondary survey aims to obtain a full and detailed history and physical exam after completion of the primary survey. Full neurological exam following International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) documentation tool should be undertaken. ASIA: International standards for neurological classification of SCI (ISNCSCI) worksheet Opens in new window A structured physical exam of the entire spine is performed during the secondary survey.[14]
The physician should examine the neck and gently palpate the posterior midline of the neck, observing for any point tenderness or overt deformity.[14] This requires additional personnel to support the patient's head and neck manually in a fixed position while the head blocks are removed and the collar is opened and gently slid out. Once these have been removed, the clinician can examine the anterior and lateral surfaces of the neck and gently palpate the entire length of the midline of the cervical spine (spinous processes) for deformity or tenderness at each vertebral level. Cervical tenderness lateral to the midline is more suggestive of muscular or soft-tissue injury, which should not impact cervical spine stability.
Neurologic examination also evaluates cranial nerve function, as injuries at the occipital-cervical spine junction can lead to brainstem injury. Strength and sensation (light touch and pinprick) should be evaluated for all myotomes and dermatomes, respectively. Deep tendon reflexes should be elicited in the upper and lower extremities. A Babinski sign (i.e., an upgoing plantar response) and a Hoffman sign (i.e., adduction of the thumb when flicking the nail of an extended finger on the same hand) are highly specific tests for upper motor neuron lesions that should be performed on all patients. Rectal exam should be performed to assess the rectal tone, perianal sensation and bulbocavernosus reflex in patients with suspected spinal cord injury. The bulbocavernosus reflex is subserved by S4-S5 nerve root and elicited by squeezing the glans penis or pulling gently on the bladder indwelling catheter. The absence of this reflex indicates that spinal shock is likely present and precludes definitive evaluation about completeness of spinal cord injury.[14] The return of the bulbocavernosus reflex heralds the end of spinal shock.
If a spinal cord injury is identified, the level of injury should be assessed using the ISNCSCI clinical documentation tool.[14]
Cervical spine imaging
The cervical collar and spinal precautions should remain in place, and cervical spine imaging is necessary, in the following situations:[14]
Altered mental status (GCS <15)
Neurological deficit (i.e., subjective limb weakness or paralysis, numbness, tingling, or dysesthesia)
High-risk injury mechanism
Neck tenderness present
Decreased range of motion of the cervical spine.
The Canadian C-Spine Rule has been designed to guide first-line physicians in emergency departments or clinical practice with regard to the management of patients who present with a history of cervical spine trauma but who are neurologically intact, awake, and alert.[28] In this scheme, patients are screened first for high-risk injury factors (e.g., age ≥65 years, dangerous mechanism, or abnormal neurologic exam). Presence of any of these factors mandates clinical imaging. Patients who then meet the low risk-factor criteria (simple rear-end motor vehicle collision; sitting in the emergency department; ambulatory at the time of injury; delayed, not immediate, onset of neck pain; or absence of midline C-spine tenderness) are further evaluated with cervical range of motion assessment. In this test, patients are asked to move their head 45º to the right and left. Failure of test (e.g., pain or inability to complete the exam) warrants further imaging and continued cervical spine motion restriction.
National Emergency X-Radiography Utilization Study (NEXUS) is similar to the Canadian C-Spine Rule.[29] This study addresses the question of when to image patients presenting with a history of cervical spine trauma. A patient who meets all 5 clinical criteria is deemed to have a low probability of injury to the cervical spine. The criteria are:
1. No tenderness at the posterior midline of the cervical spine
2. No focal neurological deficit
3. Normal level of alertness
4. No evidence of intoxication
5. No clinically apparent, painful injury that might distract the patient from the pain of a cervical spine injury.
The NEXUS and Canadian C-Spine Rule were developed and proven for use in the adult population.
After using appropriate clinical decision rules and assessing risk for spinal cord fracture or spinal cord injury during the primary and secondary survey, patients at risk for spinal trauma should be further evaluated with dedicated imaging studies.[14] Noncontrast, multidetector computed tomography (MDCT) is the initial imaging modality of choice to evaluate the cervical spine.[14] The cervical spine is imaged from the skull base or craniocervical junction, through the cervicothoracic junction. Thinner slices increase sensitivity but may add to the radiation burden. Contiguous axial slices of no greater than 3 mm are recommended to obtain reformatted images in axial, coronal, and sagittal planes in the cervical spine.[14][30] The main limitation of CT rests in its relative inability to detect changes in soft tissues, including the spinal cord and ligamentous structures.[14] Despite the high sensitivity of the MDCT in identifying bony abnormalities, interpretation may be difficult in patients with severe degenerative changes or osteopenia.[14] Plain radiographs of the cervical and thoracolumbar spine are not recommended in the initial screening of spinal trauma because of their low sensitivity.[14] Multiple randomized control trials with Class I evidence now consider plain radiography to be insufficient to identify clinically relevant fractures.[14][31][32][33][34][35] Plain films have a sensitivity ranging from 45% to 64% while modern helical cervical CT scans have sensitivity as high as 100%.[14]
In obtunded or intubated patients, the use of CT alone is sufficient to exclude unstable cervical spine injuries.[36] In the absence of CT, plain x-rays remain effective at evaluating for cervical spine misalignment, and prevertebral soft-tissue measurements. Views in this series include anteroposterior, lateral, open-mouth odontoid, and swimmer's (pull down) view. All levels between the occiput and upper half of T1 need to be visualized. If this cannot be accomplished on a lateral view, a lateral swimmer's or pulldown view is required.
[Figure caption and citation for the preceding image starts]: Common fracture patterns with severe cervical spine trauma. Top row: cervical burst fracture at C5 level; left: axial CT image showing a fracture of C5 vertebral body; right: mid-sagittal T2-weighted MRI showing retropulsion of the body of C5 with spinal cord compression, T2-weighted signal changes within the spinal cord and T2-weighted signal changes within the posterior ligamentous complex indicating disruption of these ligaments. Bottom row: fracture dislocation C6-C7 level. From left to right: lateral x-ray, axial CT through C6/C7 facet level, and T2-weighted mid-sagittal MRI demonstrating spinal cord compression and T2-weighted signal change within the spinal cordFrom the personal collection of Michael G. Fehlings [Citation ends].
Patients with persistent neck pain/midline tenderness who have cervical spine ligamentous injury are at risk of dynamic instability. Flexion-extension (F/E) cervical spine x-rays have been used to identify dynamic instability in patients with a normal cervical CT who are fully conscious and are capable of voluntary neck flexion and extension. The patient undergoes lateral cervical spine x-rays at the greatest possible neck flexion and the greatest possible extension. Any subluxation of one vertebral body relative to an adjacent one by more than 3 mm signifies the possibility of dynamic instability and raises concern for ligamentous injury. Normal F/E x-rays rule out ligamentous injury, and cervical spine precautions can be discontinued. However, given the restricted motion and limited visualization of the cervical spine in the early post-traumatic period, caution should be exerted when using this technique for ruling out ligamentous injury in the acute traumatic setting. Cervical spine MRI, rather than F/E x-rays, is usually the preferred follow-up investigation for patients with normal cervical CT where dynamic instability is suspected.[37][38][39]
MRI is complementary to CT in the assessment of cervical spinal injuries. It has high sensitivity for the identification of soft-tissue injuries and is considered the reference standard in identifying injuries to the spinal cord and discoligamentous complex. MRI is the only modality for evaluating the internal structure of the spinal cord.[14] However, caution should be taken when interpreting the MRI results as the specificity for identifying significant soft-tissue injuries is shown to be only modest. Therefore, clinical correlation is of essence in each patient scenario.[40] Furthermore, MRI is not reliable in the identification of osseous injuries. Therefore, in terms of its diagnostic values, MRI is recommended in the following clinical scenarios: patients with clinical or imaging findings suggesting mechanically unstable cervical spine or ligamentous disruption; patients with neurologic deficit, suspected spinal cord injury or nerve root injury; comatose patients with normal CT of the cervical spine, to assess for possible ligamentous injury; and patients with normal CT of the cervical spine with persistent neck pain/tenderness, to assess for possible ligamentous injury.[14][39] AOSpine guidelines suggest that when feasible and as long as there are no contraindications, MRI should be used in spinal cord injury patients prior to surgical intervention to improve clinical decision making, and before or after surgical intervention to predict the neurologic outcome.[41] Patients on ventilator support, with hemodynamic instability or who are unable to remain still for prolonged periods of time often require help from an anesthesiologist for adequate sedation.
In the event that MRI is unobtainable, CT myelogram can be used for the assessment of spinal cord compression and nerve root injury. However, the technical challenge in performing the myelogram and the poorer image quality for identifying soft tissue injury and cord compression places this technique as the second-choice imaging modality in the event of spinal injury with associated neurologic deficit.
CT angiography (CTA), combining the CT modality with the arterial phase of intravenous contrast injection, is particularly useful in visualizing the vasculature in relation to the bony structures. In the event of suspected arterial injury, CTA can positively identify all clinically relevant vascular injuries associated with blunt cervical spinal injury.[42][43] However, this technique subjects the individual to potential harm related with contrast administration, so it should only be used when clinical suspicion is high.[39] Alternatively, magnetic resonance angiogram (MRA) has been used in blunt cervical trauma for the evaluation of vascular injury. Although one study reported a slight advantage of CTA over MRA in identifying arterial injuries, literature largely supports MRA as the equivalent alternative imaging modality.[44][45][46]
Further investigation and referral
Further diagnosis and workup depends on the results of CT scans and the patient's clinical status. If a patient is neurologically intact, awake, and alert (GCS = 15) with no visible cervical spine injury on CT, but complains of persistent neck pain, the options are:
Keep in cervical spine collar
Remove cervical spine collar until normal dynamic cervical spine x-ray is obtained
Remove cervical spine collar once normal MRI cervical spine is obtained.
If the treating physician is uncertain with regard to management, a consultation with a neurosurgical or orthopedic specialist is recommended.
If the patient has a visible cervical spine injury on CT but is neurologically intact, full cervical spine immobilization measures are retained and urgent spinal orthopedic consultation obtained.
If the patient has documented cervical spine injury on CT and has neurological deficit, full cervical spine immobilization measures are retained, urgent cervical spine MRI is ordered to investigate the possibility of spinal cord compression/injury, and urgent spinal orthopedic consultation is obtained.
If a cervical spine injury or a fracture is identified, a CT scan of the whole spine is indicated to identify a concomitant thoracolumbosacral fracture.[11] See Thoracolumbar spine trauma.
Universal screening for blunt cerebrovascular injury should be considered for all patients with major trauma using a whole-body CT scan.[14] Nerve conduction studies should be ordered if radiculopathy is suspected. Slowing of nerve conduction occurs with peripheral nerve compression. Electromyography should also be ordered; the results need to be interpreted by a neurologist.
As part of the secondary survey, additional testing should be performed to exclude the possibility of additional peripheral injuries that may be confounding the patient's report of symptoms or physical exam.
Clearance of the cervical spine in obtunded patients
Obtunded patients represent a unique challenge for cervical spine clearance where the risk of missed unstable fractures must be balanced with the significant morbidity associated with prolonged spinal precautions (e.g., pressure ulcers, aspiration pneumonia, delayed mobilization, and cardiorespiratory deconditioning).
A 2015 Eastern Association for the Surgery of Trauma (EAST) guideline review found that high-quality thin-section (<3 mm axial cut) CT coupled with 1.5T MR, upright x-ray series, flexion-extension CT, and/or clinical follow-up had a worst-case 91% negative predictive value (NPV) for stable injuries (n=1718 in 11 studies).[47] In most cases, positive findings on the adjunctive assessments led to either continued collar use or discontinuation of the collar, as opposed to surgical intervention. For unstable injuries, a best-case 100% NPV was found for high-quality thin-section CT, with no cases of new neurological change (paraplegia or quadriplegia) after cervical collar removal. As a result, EAST guidelines provide a conditional recommendation to remove cervical collars after negative high-quality cervical spine CT alone in obtunded adult blunt trauma patients.[47] Subsequent studies reaffirmed this recommendation.[31][48] The American College of Surgeons recommends a negative helical cervical CT scan as sufficient to remove a cervical collar in an obtunded/unevaluable adult blunt trauma patient.[14] When available, spine surgeon consultation should be obtained to confirm the need for cervical MRI if there is clinical concern about neurologic symptoms and/or ligamentous injury referable to the spinal column.[14]
Clearance of the cervical spine: special considerations in older patients
The NEXUS criteria do not include age-related contingencies, while the Canadian C-Spine Rule considers age greater than 65 years as a risk a factor.[14] The EAST guidelines do not mention any special consideration for older adult patients.[14][47] One retrospective review found that 20% of patients older than 55 years with spine fractures (n=173) were asymptomatic, with no neck pain or neurologic deficits, and no midline tenderness on presentation for blunt trauma.[49] The rate of cervical surgery for "asymptomatic" patients older than 55 years was similar to the "symptomatic" population (19% vs. 22%).[49] The authors concluded that the presence or absence of pain may be an unreliable indicator of c-spine fracture in an aging population.[49] When used in conjunction with existing clearance guidelines, denial of pain may lead to missed injury.[49] The American College of Surgeons recommends more liberal imaging for older adults.[50]
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