Imaging modalities for spinal trauma Radiography Conventional films

Imaging modalities for spinal trauma. • Radiography. Conventional films. Flexion and Extension views. • CT-Scan. 100% sensitivity compared with 65% for plain x-ray. The reformatted images are important. • MRI. Modality of choice for evaluation of neuralelements such as cord compression, edema, hemorrhageand soft tissue structures such as ligaments injury, prevertebral hematoma and traumatic disc herniation.

C-spine Injuries. • Most common spinal injury. • Responsible for 65% of all spinal injuries. Location: • Upper cervical injuries: Include injuries to the base of the skull (Occipital condyles, C 1 and C 2 vertebra. • Lower cervical injuries(sub-axial): Include injures from C 3 through C 7 vertebra.

MECHANISMS OF SPINAL INJURY: • FLEXION INJURY: leading to anterior wedging of vertebral body with posterior longitudinal ligament/ interspinous ligament disruption. • EXTENSION INJURY: more common in cervical spine leading to posterior element fracture, anterior longitudinal ligament rupture and subluxation. • AXIAL LOADING: Diving & jumping injury leading to burst fracture and lateral element fracture. • ROTATION INJURY: leads to lateral mass fracture and facet subluxation.

Hyperflexion Injuries 1. Hyperflexion Sprain (Anterior Subluxation). 2. Bilateral Interfacetal Dislocation. 3. Simple Wedge Compression fracture. 4. Clay Shoveler’s fracture. 5. Flexion Teardrop fracture. Distraction of posterior elements and compression of the anterior column

1 - HYPERFLEXION INJURIES: Widening spinous processes. Kyphotic deformity. Widening of the posterior aspect of the involved disc spaces. • May have an impaction fracture of the anterior vertebral body. • • •

A- Anterior Subluxation (Hyperflexion Sprain) • Widening of the spinous processes. • Kyphotic deformity. • May have anterior displacement of the vertebral body. • Widening of the posterior aspect of the involved disc. • Unstable if more than 110 degree angulation.

D - Flexion Teardrop Fracture • Mechanism: Flexion and compression. • Associated with sever spinal cord injury (Anterior cord syndrome; complete paralysis, hypothesis to the level of injury). • UNSTABLE • Compression fracture of the anterior inferior of the vertebral body. • See the other sign of hyper flexion injury.

Hyperflexion Injury with Rotation. 1. Unilateral Interfacetal Dislocation: – Stable. – Anterior sub laxation of less than 50% of vertebral body on another. – Rotation of the vertebral bodies below in relation to above the injury. – Lateral displacement of the spinous process on AP view.

2 -Vertical Compression (Axial Load): • Force delivered to top of skull through the occipital condyles to the cervical spine at the instant that the cervical spine is straight • Injury Patterns: 1. Jefferson fracture. 2. Burst fracture.

Jefferson Fracture: Mechanism: Axial loading. Fractures of the anterior and posterior arches of C 1. bilateral or unilateral. Lateral displacement of the lateral mass of C 1 in relation to the lateral mass of C 2 on odontoid view. • Widening of the predental space on lateral view. • Widening of the lateral masses of C 1 in relation to C 2. • No neurologic deficit • • • UNSTABLE

Burst Fracture. • C 3 -C 7. • Usually with injury to spinal cord from the retro pulsed bone fragments.

3 - Hyperextension Injuries: 1. Widening of the anterior disc spaces. 2. Anterior avulsion fracture. 3. Narrowing of the posterior elements.

Hangman's Fracture: 4 -7% of all cervical FXs and/or dislocations. Traumatic spondylolithesis of C 2. Mechanism: hyperextension. Bilateral fractures through the pars interarticularis of C 2 in all types. • Type I (typical): Bilateral fracture of the pars interarticularis only. • Type II: Widening of C 2 -3 disc space. • Type III: Associated with anterior translation of C 2 over C 3. • •

Hyperextension Dislocation • Mechanism: Hyperextension. • Avulsion fracture of anterior aspect of the inferior end plate along with dislocation of the vertebral body. • The fragment is wider than tall; opposed to extension tear drop fracture fragment which is usually taller than wider. • Associated with sever spinal cord injury. • HIGHLY UNSTABLE.

Extension tear drop fracture: • Mechanism: Hyperextension. • Avulsion of an anterior inferior bone fragment by the anterior longitudinal ligament as a result of forced extension. • May see other sign of hyperextension injuries. • Can cause central cord syndrome. • UNSTABLE.

Rotary Atlantoaxial Dissociation (Rotary Fixation of C 1/C 2): • Usually secondary to mild trauma. • Rotation and lateral tilt at the atlantoaxial joint. • Fixation occurs when symptoms not resolved in a few days.

Odontoid (Dens) Fractures: • Mechanism: hyper extension, hyper flexion and/or rotation. • Type I: Fracture at the tip of dens. • Type II: Fracture at the base of the dens. • Type III: fracture extends to the body of the axis. • Type I and III are usually stable while type II highly unstable. • Type I difficult to see in plain film.

ATLANTO-OCCPITAL DISLOCATION: • Mechanism: Sever flexion or extension of the upper cervical spine. • Complete disruption of all ligaments between atlas and occiput. • UNSTABLE. • Anterior translation of the skull on the vertebral column is most common. • Death is usually occur. • Widening of the basion odontoid and basion axial lines.

Transverse process fracture: • Often at multiple adjacent levels. • If isolated, stable - usually a result of avulsive stress from psoas / paraspinal muscle contraction. • Can signify more severe injury. – L 5 transverse process fracture associated with sacral fracture. – nerve root injury (esp. L 5).

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