Trauma

Cervical Spine Injury Assessment

Background

1. Anatomy and Physiology
   • 7 cervical vertebrae
     • Atlas and Axis
       • Atlas formed by two lateral masses connected by anterior and posterior arches
       • Paired synovial joints allow articulation between occiput and atlas, accounting for 50% of neck flexion/extension
       • Axis has small body and odontoid process that articulates with anterior arch of C1
         • Accounts for 50% of neck rotation
       • Axis has very large, strong spinous process
         • Accommodates multiple insertions, adding to stability
       • Ligaments (cruciate, tectorial, etc.) extremely important to stability of upper cervical spine
     • C3-C7 Vertebrae
       • Vertebral bodies separated by discs
       • Pedicle and lamina extend posteriorly from body
     • Vertebral arteries travel through Transverse Processes
     • Spinous processes allow for muscle/ligamentous attachment
     • Facet joints above and below
     • Internal support provided by anterior and posterior longitudinal ligaments and posterior ligamentous complex (PLC)
   • Roles of cervical spine
     • Weight transfer of head
     • Facilitates neck motion (rotation, flexion/extension, etc.)
     • Protection of spinal cord
2. Epidemiology
   • Incidence
     • USA: 50,000-200,000 spinal fractures (all types)/year
     • 12,000 new spinal cord injuries per year
     • Spine injury occurs in 3-4% of blunt traumas
   • Location
     • 1/3 of fractures occur at C2
     • 1/2 of fractures occur at C6/C7
     • Most fatal injuries occur at base of skull-C2
   • Mechanism
     • Motor vehicle crashes account for majority of fractures and 41% of Spinal Cord Injuries (SCIs)
     • Falls, acts of violence, and sports account for remainder
   • Demographics
     • Males: 80% of spinal cord injuries
     • Blacks > Whites

Initial Management Overview

• ABCs, immobilization of C-Spine
  • Hard cervical collar is standard of care (View Video)
    • Restricts 50-80% of movement
    • Uncomfortable and can result in pressure sores with prolonged use
  • Manual stabilization and logroll precautions with all transfers
  • Airway/Breathing
    • The higher the spinal injury the more likely the need for a secured airway
    • Maintain in-line stabilization during intubation
      • Video-assisted laryngoscopy may be beneficial
  • Circulation
    • Hypotension in the suspected cervical spine injury patient may be due to
      • Hypovolemia secondary to blood loss
      • Obstructive shock (pneumothorax)
      • Cardiogenic shock (blunt cardiac injury)
      • Neurogenic shock
        • While bradycardia with hypotension may be due to neurogenic shock, medications may block the tachycardic response associated with hypovolemia and blood loss
• Neurologic Examination
  • Pupils and GCS for all traumas
  • Suspected SCI should have more detailed examination focused on
    • Sensory level
    • Motor function
    • Spinal cord reflexes
  • Repeat neuro exams every hour, with clinical change, and after all transfers and procedures
• Clinically Clearing Cervical Spine (see also NEXUS Criteria)
  • Nexus 93% sensitive for excluding clinically significant cervical fractures
    • Be wary of use in the elderly as the sensitivity has shown to be decreased in that population
  • Many ED physicians combine Nexus rules with Canadian C-Spine rules
  • As hard cervical collars are associated with discomfort and pressure sores, clearance of c-spine should be a priority
  • Be careful of overtightening the collar in head injured patients as it can increase intracranial pressure through jugular vein compression
• Imaging
  • CT has become standard imaging modality
  • Plain radiographs have lower sensitivity, are sometimes inadequate, and take longer to obtain at many centers
  • For low-risk patients with isolated neck trauma plain radiographs still a consideration, particularly if wanting to avoid excessive radiation
  • MRI is frequently used in the evaluation of SCI or soft tissue injury

Stability Assessment

• Definition of Stable: ability of spinal column to maintain normal alignment and protect neural elements during usual activities and physiologic loads
• Injury Pattern (See Stability)
  • Most frequently used method characterization
  • Uses radiology findings to characterize fractures and dislocations
  • Injury patterns are categorized as stable or unstable
• Injury Mechanism (See Mechanisms)
  • Generally used to categorize different injury patterns and describe pathogenesis of different injuries
  • Some have developed grading scales for injury patterns to quantify the complexity and seriousness of different injury types
  • Generally applied to subaxial injuries
• White and Panjabi System (Open Calc)
  • Developed in 1978
  • Uses radiographic findings, neurologic examination, and anticipated demands of the patient to determine stability
  • Based on calculated score, fractures labeled as stable or unstable
  • Some scoring parameters can be difficult to assess
• Subaxial Injury Classification (Open Calc)
  • Very useful for C3-C7 injuries
  • Incorporates fracture type, neurologic status, and integrity of the discoligamentous complex (DLC)
  • DLC stabilizes the spine and includes the disc, facet joint capsule, ligamentum flavum, and spinal ligaments
  • Scores > 4 are operative candidates

Stability Ranking: MOST unstable (1) to LEAST unstable (15)

1. Rupture of the transverse ligament of the atlas
2. Fracture of the dens (odontoid fracture)
3. Flexion teardrop fracture (burst fracture with posterior ligamentous disruption)
4. Bilateral facet dislocation
5. Burst fracture without posterior ligamentous disruption
6. Hyperextension fracture dislocation
7. Hangman's fracture
8. Extension teardrop (stable in flexion)
9. Jefferson fracture (burst fracture of the ring of C1)
10. Unilateral facet dislocation
11. Anterior subluxation
12. Simple wedge compression fracture (without posterior disruption)
13. Pillar fracture
14. Fracture of the posterior arch of C1
15. Spinous process fracture (clay shoveler fracture)

Specific Injuries: Stable And Unstable

• Occipitocervical Dislocation
  • Diagnosed by the Harris Rule of 12
    • Basion-posterior axial line interval (BAI): drawn along posterior aspect of dens and measured between this line and tip of basion
    • Basion-dental interval (BDI): distance measured between tip of basion and tip of dens
    • If BDI and BAI > 12 mm: occipito-atlantal dissociations has occurred
  • Classified by dislocation of the occiput relative to C1
  • All injuries are considered highly UNSTABLE
• Occipital Condyle Fractures
  • Type I: an impaction fracture from axial loading; STABLE
  • Type II: a basilar skull fracture with extension; STABLE
  • Type III: an avulsion injury; potentially UNSTABLE
• Atlas Fractures
  • Isolated Anterior and Posterior arch fractures; generally STABLE
  • Jefferson Burst Fractures and fractures of Lateral Masses; generally UNSTABLE
• Atlantoaxial Instability
  • Four Types
  • All are considered highly UNSTABLE
• Odontoid Fractures
  • Three Types
  • May be STABLE or UNSTABLE
  • Ligamentous/concomitant injuries tend to produce the instability
  • Greatest concern for unstable injuries is non-union/poor outcome
• Hangman's Fracture
  • Type I is STABLE
  • Type II has disruption of C2-C3 disk and posterior longitudinal ligament
    • Resulting in > 3 mm translation and significant angulation; UNSTABLE
  • Overall, incidence of cord injury is low
• Flexion-Compression Injuries
  • Vertebral Body Compression Fractures; generally STABLE
  • Teardrop fractures may have ligamentous disruption; potentially UNSTABLE
  • Posterior subluxation of posterior vertebral body into canal is most severe flexion-compression injury
    • Highly UNSTABLE
• Flexion-Distraction
  • Facet Subluxation: Potentially UNSTABLE
  • Unilateral facet dislocation: Potentially UNSTABLE
  • Facet fracture-dislocations: Potentially UNSTABLE
  • Bilateral facet dislocations
    • Essentially a pure soft tissue injury
    • Multiple structures completely torn
      • Posterior complex
      • Posterior longitudinal ligament
      • Intervertebral disc
      • Anterior longitudinal ligament
    • Highly UNSTABLE
• Axial (vertical) Compression Injuries
  • Wide range of injuries
  • Generally UNSTABLE
• Extension Injuries
  • Disruption of the ALL and Disc
    • Often have normal vertebral alignment but diffuse soft tissue swelling
    • UNSTABLE
  • Disruption of posterior ligament with disruption of cephalad vertebrae into canal
    • Highly UNSTABLE
  • Extension tear-drop fracture
    • Usually seen with osteoporosis/osteoarthritis of C-spine
    • STABLE in FLEXION
    • UNSTABLE in EXTENSION
  • Central Cord Syndrome: STABLE
  • Spinous Process Fracture
    • STABLE
    • Avulsion injury of spinous process
    • Found in C6, C7, or T1
    • From extension of neck against flexed soft tissue
  • Pillar fracture
    • STABLE
    • Caused by extension + rotation

References

1. Mattox KL, Moore, EE, Feliciano DV. Trauma, 7th Ed., 2013 McGraw-Hill
2. Go S. Spine Trauma. Tintinalli's Emergency Medicine; A Comprehensive Study Guide, 8th ed., McGraw-Hill Education, 2015;pp.1708–1724
3. Feuchtbaum E, et al. Subaxial Cervical Spine Trauma. Current Reviews in Musculoskeletal Medicine, 2016;9(4):496–504
4. Aarabi B, et al. Subaxial Cervical Spine Injury Classification Systems. Neurosurgery, 2013;72:170–186
5. Vaccaro AR, Hulbert RJ, Patel AA, et al. Spine Trauma Study Group. The subaxial cervical spine injury classification system: a novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex. Spine (Phila:Pa, 1976). Oct 1, 2007;32(21):2365-2374
6. Dickinson G, Stiell IG, Schull M, et al. Retrospective application of the NEXUS low-risk criteria for cervical spine radiography in Canadian emergency departments. Ann of Emerg Med. Apr 2004;43(4):507-514
7. Bransford RJ, et al. Upper Cervical Spine Trauma. Journal of the American Academy of Orthopaedic Surgeons, 2014;22(11):718–729

Contributor(s)

1. Iteen, Alex, MD
2. Austin, Andrea, MD
3. Latham, Douglas E., MD

Updated/Reviewed: February 2019