C-Spinal Injury and Diagnosis

Approach to C-spine x-rays

3-view C-spine series is the screening modality of choice:

1.     Lateral C1~T1 +/- swimmer’s view

a.     Lateral view is best; it identifies 90~95% of injuries

2.     Odontoid view (open mouth or oblique submental view)

a.     Examine the dens for fractures

                                               i.     If unable to rule out fracture, repeat view or consider CT or plain film tomography

b.     Examine lateral aspects of C1 and spacing relative to C2

3.     AP view

a.     Alignment of spinous processes in the midline

b.     Spacing of spinous processes should be equal

c.      Check vertebral bodies and facet dislocations

Normal Swimmer’s view x-ray

The ABCS of lateral view

A—adequacy and alignment

·      Must see C1~T1 junction; if not, downward traction of shoulders, swimmer’s view, bilateral supine oblique, or CT scan are needed.

·      Lines of contour in children < 8 yr of age, can see physiologic subluxation of C2 on C3, and C3 on C4, but the spino-laminal line is maintained.

·      Fanning of spinous processes suggests posterior ligamentous disruption

·      Widening of facet joints

·      Check atlanto-occipital joint

·      Line extending inferiorly from clivus should transect odontoid (Wackenheim or clivus-canal line)

·      Atlanto-axial articulation, widening of predental space (normal: < 3mm in adults; < 5mm in children) indicates injury of C1 or C2

B—bones

·      Height, width, and shape of each vertebral body

·      Pedicles, facets, and laminae should appear as one—doubling suggests rotation

C—cartilage

·      Intervertebral disc spaces—wedging anteriorly or posteriorly suggests vertebral compression

S—soft tissue

·      Widening of retropharyngeal space (normal: < 7 mm at C1~C4; may be wide in children < 2yrs. on expiration) or retrotracheal spaces (normal: < 22mm at C6~T1; < 14mm in children < 5yrs.)

Supine oblique views, though rarely used, are better visualization of posterior element fractures (lamina, pedicle, facet joint) and is good for assessing the patency of neural foramina; it can also be used to visualize the C7~T1 junction.

Sequelae of C-spine fractures:

·      Acute phase of spinal cord injury

o   Spinal shock—absence of all voluntary and reflex activity below level of injury

§  Decreased reflexes, no sensation, flaccid paralysis below level of injury, lasting days to months

o   Neurogenic shock—loss of vasomotor tone, SNS tone

§  Watch for hypotension (lacking SNS), bradycardia (unopposed PNS), and poikilothermia (inability to maintain constant core temperature due to lacking SNS so no shunting of blood from extremities to core).

§  Occurs within 30min of spinal cord injury at level T6 or above, lasting up to 6 weeks

§  Provide airway support, fluids, atropine (for bradycardia), vasopressors for BP support

·      Chronic phase

o   Autonomic dysreflexia—in patients with a spinal cord injury at level T6 or above

§  Symptoms and signs include pounding headache, nasal congestion, feeling of apprehension or anxiety, visual changes, dangerously increased blood pressure. (Think opposite of neurogenic shock!)

§  Common triggers

·      GU causes—bladder distention, UTI, kidney stones

·      GI causes—fecal impaction or bowel distention

§  Treatment—monitoring and controlling blood pressure, prior to addressing causative issue

20% of C-spine fractures are accompanied by other spinal fractures so ensure thoracic and lumbar spinal x-rays are normal before proceeding to operating theatre.