Spine Trauma

Spine Trauma – Part A
By:Keith Wilkinson MD FACEP
Keith Wilkinson MD FACEP
St. John Hospital and Medical Center

Spinal Cord Injury
* Background:
o 8,000 -10,000 new cases expected annually
o Young men- mean age 33.5
o More frequently on weekends, holidays, during summer months
* Greater than half of cord injuries occur in the cervical spine region, a third in the thoracic region, and the remainder in the lumbosacral area
* Most cases of spine injury do not involve permanent cord injury
* Majority (90%) caused by blunt
trauma
o Majority from MVCs > falls, gunshot wounds, sports/ recreational activities
Bony Anatomy
Vertebral Anatomy
Anatomy
* Spinal cord occupies:
o ~35% of canal at the level of the Atlas
o ~ 50% of the canal in the lower cervical region (C2-7), thoracolumbar spine
Ventral- front
Dorsal- back
Ascending Spinal Cord Tracks
Dorsal column- medial lemniscus
Ipsilateral loss of tactile discrimination, vibration, joint and muscle proprioception
Leg fibers medial, arms lateral
Crosses just below level of medulla
Dorsal spinocerebellar tract
Transmits unconscious proprioceptive information to cerebellum
Fine coordination of posture
An uncrossed tract
Ipsilateral leg dystaxia
Ventral spinocerebellar tract

Unconscious proprioceptive information to cerebellum
Posture of lower extremities
Crossed tract
Contralateral leg dystaxia
Ascending Spinal Cord Tracks
Lateral spinothalamic tract
Pain and temperature
Crossed tract
Contralateral loss of pain and temperature sensation one segment below lesion
Ventral white commissure
Bilateral loss of pain and temperature
Dorsal Horn
Ipsilateral segmental anesthesia and areflexia
Descending Spinal Cord Tracks
Lateral corticospinal tract
Also called pyramidal system
Volitional motion
90% crossed in medulla
Ipsilateral spastic paresis with pyramidal signs
Ventral corticospinal tract
Mild contralateral muscle weakness
Proximal muscles more affected

Ventral horn
Ipsilateral flaccid paralysis
Dermatome Distribution
Spinal Level Muscle Innervation
Muscle Strength Grading
* 0 Flaccid
* 1 Flicker of muscle contraction
* 2 Full range of motion, gravity excluded
* 3 Full range of motion against gravity only
* 4 Full range of motion against gravity and some external resistance
* 5 Normal

Stability of Spine Fractures
* Three columns-Disruption of 2/3 unstable
A.Anterior column- anterior vertebral body, the anterior annulus fibrosus, anterior longitudinal ligament
B.Middle column-posterior vertebral body wall,posterior annulus fibrosus, posterior longitudinal ligament
C.Posterior column-posterior vertebral arch, posterior ligamentous complex
* Degree of compression
+ Vertebral body compressions > 50 %
generally considered unstable

Spine Fracture Types
* Compression fractures
o Result from axial loading and flexion,
o Failure of the anterior column
o Middle, posterior columns intact
o Usually stable unless > 50% height
o Unlikely to be directly responsible for neurologic damage

Burst Fractures
* Axial load
* Both anterior and middle columns fail
* Retropulsion of bone and disk fragments into the canal
* May cause spinal cord compression

Fracture Dislocations
* Fracture-dislocations
o Most damaging of injuries
o Failure of all three columns
o Compression, flexion, distraction, rotation, or shearing forces

Flexion- distraction
* Seat belt–type injuries
o Particularly where lap belts alone are used
* Failure of both the posterior and middle columns
o Intact anterior column prevents subluxation
* Radiographic findings:
o Increased height of the posterior vertebral body
o Fracture of posterior wall of the vertebral body
o Posterior opening of the disk space.


Clinical Clearance of the Cervical Spine
Cervical spine injury is highly unlikely if the patient has

1) No neck pain or tenderness
2) No neurologic signs or symptoms
3) No loss of consciousness
4) Normal mental status
5) No distracting injury

Cervical spine series
* Sensitivities for a cross table lateral demonstrating all 7 cervical vertebra vary (77- 90%)
* Sensitivity of full three view series (lateral, AP and odontoid views) increases to 80% to 100%
o Odontoid 10%, AP 1%
* If cervical fracture found:
o 50% have fx at adjacent level
o 15% have fx in another part of cervical spine
o 10% have fx in thoracic/lumbar spine

Interpreting Cervical Spine X-rays
* True lateral identifies 80- 90% of significant bony or ligamentous lesions
o Adequate films
+ Full visualization of all seven vertebrae
+ C7-T1 injuries are not common, seen with swimmer's view
* Open-mouth odontoid view identifies most of the remaining 10% of significant lesions
o Look for normal alignment and equal spacing between C2 and the lateral masses of C1
* AP or oblique views rarely identifies injury not already suspected

Cervical Spine Radiographs
* Most missed fractures due to inadequate films of the cervico-cranium, C7- T1 junction
* Cervical CT should be used to assess C1-C2 in victims of severe head trauma (GCS < 10, intracranial hemorrhage, skull fractures), when unable to obtain an open mouth or anteroposterior odontoid view
* The open mouth odontoid view is unreliable in unconscious intubated patients missing nearly 16% of injuries
* Up to 15% of cervical spine injuries are missed when the lateral view alone is used to clear patients
* Addition of CT increases sensitivity to 95-100%

Cervical Spine Radiology and the Unconscious Patient

Cervical Spine Radiology
Dens view
Fuchs view
Cervical Spine Radiology
Swimmer’s View
Cervical Spine Radiology
* Look for
o Normal atlanto-occipital alignment
o Predental space 3 mm or less
o Prevertebral soft tissue space less than 5 mm anterior to C3
o Spinal canal plain film anteroposterior diameter 13 mm or greater
o Any horizontal translation of one vertebra on the next
o Fanning of the space between spinous processes
o Fracture of any bone

3 Rules of 3
* The predentate space should be < 3mm
* The prevertebral soft tissue at C3 is usually 3 mm
* Anterior wedging of 3mm or more suggests a fx
Flexion/ extension views
o Used carefully to demonstrate spinal column stability if the initial three views raise a question but would predict a stable spinal column
+ Small chip fracture of the anterior-inferior margin of the vertebral body
+ 1 to 2 mm with no other noted abnormalities
o Used when the initial three views are normal but the pain seems out of proportion, suggesting greater occult ligamentous damage
o Requires awake, cooperative patient
o Abnormal if there is more than a 3.7-mm step-off of one vertebra on the next or if there is an 11° or greater angulation between vertebral segments
* Flexion-extension views
o No urgency
o Fluoroscopic examination of the unconscious patients has a specificity of about 99% and a sensitivity of 92%
o 625 patients with two suffering neurological deterioration, one with complete quadriplegia

Spine Imaging
* CT/ MRI
o The incidence of unstable spinal injury in the unconscious intubated patient is about 10%
o MRI not as sensitive as CT for imaging bone injuries
o MRI- Superb at defining neurologic, muscular, and soft tissue injury
+ MRI may also be used to identify ligamentous injury
+ Indicated in all patients with neurologic symptoms or physical findings but no clear explanation on plain films and/or CT
CT
* Excellent for upper spine anatomy, rotational injuries, degenerative vs. acute subluxations, subtle compressions
o High incidence of upper cord injury with ICH, GCS < 8
* 3-d reconstructions add improved detail

MRI
Unstable Cervical Spine Fractures
* Jefferson fracture
* Hangman’s fracture
* Teardrop fracture
* Bilateral locked facets

C spine Mechanism of Injury
HYPERFLEXION INJURY (46-79%)
* odontoid fracture
* simple wedge fracture (stable)
* tear drop fracture
* anterior subluxation
* bilateral locked facets (unstable)
* anterior disc space narrowing
* widened interspinous distance
* clay shoveler’s fracture
HYPEREXTENSION INJURY (20-38%)
* anteriorly widened disc space
* prevertebral swelling
* tear drop fracture
* neural arch fracture of C1
* subluxation (anterior/posterior)
* hangman’s fracture
Unstable Cervical Spine Fractures
* FLEXION:
o bilateral interfacetal dislocation
o flexion teardrop fracture (usually C5 or C6)
* EXTENSION:
o extension teardrop (usually C2 or C3)
o hangman’s fracture
o extension-dislocation
o extension-fracture-dislocation
o odontoid fracture
* VERTICAL COMPRESSION:
o Jefferson burst fracture

Spine Trauma – Part A
Spine Trauma – Part B