Spinal trauma

Introduction

• 81% male predominance of spinal cord injury in US
• MVA 37%, falls 29%, violence 14%
• Cervical spine is most commonly injured due to its flexibility
• Most injuries at C2 and from C5-7
• Second most common site is thoracolumbar transition zone
• 20% rate of non-contiguous fracture site
• Down syndrome predisposes to atlanto-axial dislocation
• RA predisposes to rupture of transverse ligament of C2

Anatomy

• Anterior body and posterior arch
• Posterior arch consists of:
  • Two pedicles
  • Two laminae
  • Seven processes (one spinous, two transverse and four articular)

• Spinal cord
  • Foramen magnum to L1/2 (L3 at birth)
  • 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal pairs of spinal nerves
  • Each spinal nerve emerges through the intervertebral foramen corresponding to the appropriate spinal cord level
    • C1 above C1
    • C8 below C7
    • T1 below T1 and onwards
  • Lower nerve roots form the cauda equina

• Horizontal vs. vertical nerve roots
  • Cervical nerve roots run horizontally above the corresponding pedicle
    • Central and paraforaminal disc herniations will affect the same nerve root
  • Lumbar nerve roots run vertically before exiting spinal canal and exit below the corresponding pedicle
    • Central and paraforaminal herniations will affect different nerve roots

• Sympathetic system
  • 22 ganglia – 3 cervical, 11 thoracic, 4 lumbar and 4 sacral
  • Stellate, middle and superior cervical ganglia
  • Lumbar sympathetic fibres (splanchnic nerves) continue to the hypogastric plexus
• Parasympathetic system
  • S2-4 parasymphathetic fibres to the hypogastric plexus

• Blood supply
  • Anterior spinal artery
    • Supplies 2/3 of anterior spinal cord including the ventral and lateral corticospinal tract (Light touch, pain and temperature + motor function
  • Artery of Adamkiewicz
    • Largest anterior segmental artery
    • Usually from left posterior intercostal artery
    • Supplies lower 2/3 of spinal cord via the anterior spinal artery
    • 75% originate on left between T8 and L1
  • Posterior spinal artery
    • Supplies dorsal sensory columns (vibration and proprioception)

Spine biomechanics

• Cervical spine
  • Two columns below C2
    • Anterior – Vertebral bodies and discs held by ALL and PLL
    • Posterior – Pedicles, transverse processes, articulating facets, laminae and spinous processes + Nuchal ligament complex
    • Risk of spinal injury much less if only one column involved

Denis three column theory

• Moderately reliable in determining clinical stability
• 2 of 3 columns are required for stability
• Columns
  • Anterior column = ALL + anterior 2/3 of body + annulus
  • Middle column = Posterior 1/3 of body + PLL + annulus
  • Posterior column = Pedicles, facets, ligamentum flavum, spinous processes and posterior ligamentous complex
• Unstable
  • Injury to middle column
  • Disruption of posterior ligamentous complex with any anterior or middle column involvement
• Posterior spinous ligamentous complex
  • Supraspinous ligament
  • Interspinous ligament
  • Ligamentum flavum
  • Facet capsules

ASIA classification

• Need to ensure not in spinal shock (i.e. bulbocavernosus reflex should be present)
• Determine neurological level
  • Lowest segment with intact sensation and at least 3/5 muscle function strength with all cephalad levels 5/5
  • Usually different on each side so report this in documentation
• Complete (ASIA A)
  • No voluntary anal contraction (sacral sparing) AND
  • 0/5 distal motor
  • 0/2 distal sensory (no perianal sensation)
  • Bulbocavernosus reflex present
• Incomplete
  • Voluntary anal contraction (sacral sparing)
  • Palpable or visible muscle contraction below level
  • Perianal sensation remains

ASIA scale

• A – Complete
• B – Incomplete. Sensory but not motor function is preserved below neurological level and includes sacral levels S4-5
• C – Incomplete. Motor function preserved below neurological level and more than half of key muscles below neurological level have muscle grade <3
• D – Incomplete. Motor function preserved below neurological level and at least half of key muscles below level have muscle grade >= 3
• E – Normal.

Signs of spinal cord injury in unconscious

• Response to pain above but not below a suspected level
• Flaccid areflexia in arms and/or legs
• Elbow flexion with inability to extend suggests cervical SCI
• Paradoxical breathing pattern (indrawing of upper chest on inspiration)
• Inappropriate vasodilatation
• Unexplained bradycardia/hypotension
• Priapism
• Loss of anal tone and reflexes

Cord syndromes

Central cord syndrome

• Most common incomplete cord injury
• Typically elderly with minor extension injuries
• Arms > Legs (as arm corticospinal tract fibres run medially)
• Presentations
  • Weakness with poor hand dexterity
  • Burning in upper distal extremity
  • Sacral sparing
  • Late presentation is upper limb lower motor neuron signs and lower limp upper motor neuron signs
• Good prognosis for improvement

Anterior cord syndrome

• Usually flexion/compression injury or anterior spinal artery injury
• Presentation
  • Lower extremity > upper extremity
  • Loss of lateral corticospinal tract (motor) and lateral spinothalamic tract (pain/temp)
  • Dorsal columns preserved
• Poor prognosis with only 10-20% chance of motor recovery

Brown-sequard syndrome

• Cord hemitransection
• Ipsilateral loss of motor (lateral corticospinal tract) and vibration/proprioception (dorsal columns) +
• Contralateral loss of pain/temp (lateral spinothalamic tract) as these fibres decussate only 2 levels higher
• Excellent prognosis

Posterior cord syndrome

• Very rare with loss of proprioception/vibriosense
• Preserved motor/light touch/pain/temp sensation

Cervical spine fractures

• Flexion-type injuries
  • Anterior subluxation
  • Atlantoaxial dislocation
  • Bilateral interfacetal dislocation
  • Simple wedge compression fractures
  • Spinous process avulsion (Clay-shoveller’s fracture)
  • Flexion teardrop fracture
• Flexion-rotation injuries
  • Unilateral facet dislocation
  • Fracture of lateral mass
• Vertical compression
  • Jefferson burst fracture of Atlas
  • Burst fracture
• Extension-type injuries
  • Hyperextension dislocation
  • Hyperextension teardrop
  • Extension corner avulsion fracture
  • Fracture of posterior arch of atlas
  • Laminar fracture
  • Hangman’s fracture
• Combined
  • Occipital condyle fractures
  • Atlanto-occipital dissociation
  • Odontoid fractures

C-spine: Anterior subluxation (hyperflexion sprain)

• Usually stable but depends on posterior ligament integrity
• Up to 1mm of anterior subluxation is allowed in adults (3mm in children)
• May have no associated fractures and only be evident by soft tissue swelling, fanning of spinous processes, posterior widening of intervertebral disc space or cervical disc space alignment >11 degrees between adjacent spaces

Atlanto-occipital dislocation

• Caused by pure flexion injury
• Harris’ lines >12mm suggests this = Basion-posterior axial line interval + Basion-dental interval
• Powers ratio >1 suggests this
  • BC:OA
  • Basion-midpoint of posterior laminar line of C1: Midpoint of posterior margin of foramen magnum (opisthion) and midpoint of posterior surface of anterior arch of C1

Atlanto-occipital dissociation (AOD)

• •Highly unstable
• •High-energy impact with high mortality
• •Classic presentation
  • Paralysis of upper extremities with normal lower limbs
  • Lower cranial nerve deficits common

Atlanto-occipital dislocation

Atlanto-occipital dislocation

Atlantoaxial dislocation

• •Transverse ligament rupture without fracture
• •Seen in elderly patients from direct blow to occiput
• •Measurement of predental space is key to diagnosis
  • Posterior aspect of anterior arch of C1 to dens
    • >3mm on plain film = damage
    • >2mm on CT = damage
    • > 5mm = complete rupture
• Rotary atlanto-axial dislocation is unstable due to flexion-rotation

Atlantoaxial dislocation

Jefferson burst fracture

• Atlas vertical compression fracture
• Fracture of anterior and posterior arches of C1
• Highly unstable
• Also causes prevertebral haemorrhage with predental space >3mm (>5mm in children)
• Drive lateral masses of C1 apart
• If displacement of both lateral masses (as offset from the superior corner of C2 vertebral body) is >7mm when added together, rupture of transverse ligament is likely and injury is unstable

Jefferson burst fracture

Posterior arch of C1

• Due to compression in extension
• Mechanically stable as anterior arch and transverse ligament are intact, but functionally can cause spinal cord damage with as little as 1cm of anterior displacement

Bilateral interfacetal dislocation

• •“Locked facets” – Inferior articulating facets of upper vertebrae pass over superior facets of inferior vertebrae and sit in intervertebral foramens bilaterally causing anterior displacement of the spine
• •Involves disruption of all ligamentous structures due to severe flexion-distraction
• •Vertebral body dislocates anteriorly on vertebra below and >50% of its width
• •Get compromise of intervertebral foramen with neurological deficits and complete cord injury
• •Inherently unstable as annulus fibrosis and ALL both damaged
• •Can get “perched facets” if only partial dislocation from lesser flexion-distraction mechanism. Considered unstable but may not have spinal cord or nerve injury

Unilateral facet dislocation

• From flexion-distraction + rotation mechanism
• <50% anterolisthesis of superior vertebral body on inferior one
• Usually nerve root compression but not cord compression
• Clinically stable but treat as unstable in ED until spinal consult

Unilateral facet dislocation

• Flexion-rotation mechanism
• Articular mass and articular inferior facet dislocated unilaterally
• Vertebral body displaced <50% of width
• On AP film, spinous process will point towards dislocated side
• Stable unless associated articular mass #

Unilateral facet dislocation

Unilateral facet dislocation

Perched facets

Bilateral interfacetal dislocation

Anterior wedge cervical spine

• Forceful flexion
• Unstable if >50% loss of height (same as TL) or multiple adjacent wedge compression fractures

Spinous process avulsion fracture

• Clay shoveler’s fracture
• Avulsion typically off C7 spinous process
• No neurological compromise

Flexion teardrop fracture

• Highly unstable
• Extreme hyperflexion with total ligamentous disruption
• Antero-inferior portion of vertebral body (teardrop) is displaced by the ALL
• Fanning of spinous process
• Anterior spinal cord syndrome results
• Posterior longitudinal ligament is disrupted
• Get associated loss of height of affected vertebrae (unlike extension teardrop)

Flexion teardrop fracture

Hyperextension dislocation

• Extreme hyperextension leads to ALL rupture with intervertebral disc rupture and disruption of the anterior ligamentous complex
• Prevertebral soft tissue swelling may be the only clue
• Anterior disc space widening or fracture of the anteroinferior end plate of the vertebral body may occur (similar to teardrop fracture)
• Taller than it is wide though and occurs around C2 usually
• Usually present with central cord syndrome
• Vertebra doesn’t lose height normally (unlike flexion teardrops)
• Inherently unstable

Occipital condyle fractures

• Presentation often involves lower cranial nerve deficits and/or limb weakness
• Usually only diagnosed on CT

Odontoid (dens) fractures

• Typically involves other spinal injuries/multitrauma
• Usually from forced flexion or extension e.g. fall onto forehead
• Neurological injury in 18-25% of cases
• CT can miss this if fracture line is aligned with CT cut (en face)
• Type I (tip)
  • Stable
• Type II (base) – Most common
  • Unstable
• Type III (extending into C2 body)
  • Unstable

Odontoid fractures

Fracture of lateral mass

• Typically severe neck pain +- radicular symptoms +- Brown-Sequard syndrome +- Vertebral artery injury
• Flexion-rotation mechanism
• MRI recommended for all

Cervical burst fracture

• May cause end-plate fractures
• Characteristic loss of height, comminution and vertical fracture line on AP
• Technically stable as all ligaments are intact, retropulsion may impinge on spinal cord
• Unstable if:
  • Associated neurology
  • >50% vertebral body height loss
  • >20 degrees angulation
  • >50% compromise of spinal canal

Thoracolumbar fractures

• Flexion-type
  • Simple wedge compression fracture
• Flexion-Distraction
  • Chance fracture (anterior compression with associated transverse fracture through the vertebral body)
• Vertical compression
  • Burst fracture
• Combination mechanism
  • Translational fracture-dislocation

• Stability
  • Determined by 2 out of 3 columns intact +-
  • >50% loss of height 
  • Compression fractures with >30 degrees angulation and Burst fractures with >25 degrees angulation = unstable
  • Neurological deficit
  • Compression fractures at multiple levels
• Cadaveric studies found middle column is most crucial to stability
• Measure angles at intersection of two lines:
  • One along superior endplate of one vertebral level above fracture
  • One along inferior endplate of one vertebral level below fracture

AO thoracolumbar spine classification

• Neurological signs (N)
  • N0: no focal neurological signs present
  • N1: a history of transient neurological deficit
  • N2: current signs or symptoms of radiculopathy
  • N3: an incomplete spinal cord or cauda equina injury
  • N4: complete spinal cord injury (complete absence of motor and sensory function; ASIA A)
  • NX: cannot be assessed (e.g., due to head injury, intoxication, sedation)
• Modifiers (M)
  • M1: the presence of tension band injury is indeterminate (whether or not MRI was performed); applies to injuries that seem stable from a bony standpoint (type A) but the possibility of ligamentous insufficiency (type B) remains, which would guide consideration of operative stabilisation
  • M2: the presence of co-morbid conditions such as ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis, osteopenia, osteoporosis, overlying burns, etc.
• Scoring system
  • Injury type:
    • A0: 0 points
    • A1: 1 point
    • A2: 2 points
    • A3: 3 points
    • A4: 5 points
    • B1: 5 points
    • B2: 6 points
    • B3: 7 points
    • C: 8 points
  • Neurologic status:
    • N0: 0 points
    • N1: 1 point
    • N2: 2 points
    • N3: 4 points
    • N4: 4 points
    • NX: 3 points
  • Patient-specific modifiers:
    • M1: 1 point
    • M2: 0 points
• Total score
  • 0-3 = Conservative Mx
  • 4-5 = Non-operative or operative
  • >5 = Surgical intervention recommended

Chance fracture

• Flexion-distraction injury
• Anterior compression with associated transverse fracture through vertebral body
• Unstable
• Occur at TL transition zone mostly
• Can easily be misdiagnosed as anterior wedge compression fracture
• Clues are fanning of spinous processes, posterior vertebral body wall fracture, increased height of posterior vertebra
• Small bowel and mesenteric injuries are common
• Neurological deficits are rare

Chance fracture

Simple wedge compression fracture

• Makes up 52% of thoracic fractures
• Flexion compression injury
• Typically superior end plate involved only
• If posterior ligamentous disruption co-exists = unstable
• Differentiated from burst fracture by absence of vertical fracture through vertebral body and lack of bulging of posterior vertebral border
  • This is crucial and is easily missed even by specialists (20% in one study)

Burst fracture

• Vertical compression
• Differentiated from anterior wedge compression fracture by bowing or fracture of posterior vertebral body wall
• May get vertical fracture through vertebral body also and widening of the interpedicular distance on AP view
• Spinal cord may be injured by retropulsed fragment
• Unstable as neuro deficit in around 50%

Burst fracture

Translational fracture-dislocation

• High-energy disruption of all three columns of TL spine
• From massive direct trauma to the spine
• T10-L2 is most common
• Lesions above T7 can be stable if rib cage intact
• Below T7 all are unstable

Translational fracture-dislocation

Others

• Minor spinal fractures
  • Isolated transverse process fractures
  • Spinous process fractures
  • Facet or laminar fractures
  • Bipedicular fractures
  • Pars interarticularis fractures
• Mostly in lumbar region from direct blows or sudden contraction of psoas on transverse process

Sacral fractures

• Usually associated with other pelvic fractures
• Transverse fractures through body cause cauda equina
• Longitudinal fractures can cause radiculopathy
• Central sacral fracture can present with bladder/bowel incontinence
• Anatomy
  • L5 runs on top of sacral ala
  • S1-4 transmitted through sacral foramina
    • S1-2 carry higher rates of injury
  • S2-5 functions
    • Anal sphincter tone, voluntary contracture, bulbocavernosus reflex and perianal sensation

• Denis classification
  • Zone 1: Lateral to foramina
    • Most common (50%)
    • Nerve injury rare (sometimes L5) only 6%
  • Zone 2: Through foramina
    • If shear component = highly unstable
    • Neuro injury in 28%. L5/S1/S2
  • Zone 3: Medial to foramina into spinal canal
    • 60% have neurological deficit (bladder/bowel/sexual)
  • Transverse have high rate of nerve dysfunction
  • U-type sacral fractures
    • Due to axial loading
    • Spino-pelvic dissociation
    • High incidence of neurological complications

Sacral fractures

• Only 30% seen on plain films
• CT is study of choice

Coccyx fracture

• Usually direct fall on buttocks
• Imaging is not compulsory and nor is PR
• Treatment is symptomatic with analgesics and donut

Spinal cord injury
 – Pathophysiology

• Primary injury
  • Mechanical forces from traumatic impact
• Secondary injury
  • Haemorrhage into cord and oedema
  • Local spinal cord ischaemia due to oedema and local vasospasm and thrombosis of arterioles in gray and white matter
  • Secondary tissue degeneration then ensues within hours associated with neural membrane dysfunction, driven by pathology sodium channel excitation, influx of calcium and release of glutamine

Spinal cord lesions

• Lateral corticospinal tract injury
  • Ipsilateral motor UMN findings
• Spinothalamic tracts
  • Contralateral pain/temp loss starting 1-2 levels below the lesion
• Dorsal columns
  • Ipsilateral vibration/proprioception loss beginning at level of lesion (decussate at gracile/cuneate nuclei)
• Remember, light touch is not completely lost unless both the dorsal and spinothalamic tracts are lost

Initial ED stabilisation

• Airway
  • Many experts advocate I&V for any lesion C5 and above
    • Prevents delayed respiratory compromise as patients tire from intercostal/abdominal breathing patterns and inability to cough due to abdominal wall paralysis
  • Diaphragm innervated by C3-5
    • With C5 SCI: Diaphragm intact but 50% still require short term MV
    • With C4 SCI: Partial loss of diaphragm innervation and nearly all need short-term MV
    • With C3 SCI: All need initial MV and 50% will need permanent MV
    • If C5 or above, strongly consider early intubation
  • Video laryngoscopy improves intubation success rates
  • In-line immobilisation demonstrates less cervical motion than cervical collars

Neurological examination

• Spinal tenderness/step
• Determine level of motor loss
• Determine level of sensory loss
  • Pain/temp + vibration/proprioception
  • Saddle anaesthesia
• Deep tendon reflexes
• Anogenital reflexes (as incomplete if present)
  • Bulbocavernosus
  • Rectal tone
  • Cremasteric reflex
  • Anal wink
  • Priapism indicates complete spinal cord injury

Myotomes

• C5 – Elbow flexion
• C6 – Wrist extension
• C7 – Elbow extension
• C8 – Finger flexion/extension
• T1 – Finger abduction
• L2 – Hip flexion
• L3 – Knee extension
• L4 – Ankle dorsiflexion
• L5 – Hallux dorsiflexion
• S1 – Ankle plantarflexion
• S2 – Knee flexion

Dermatomes

• C2 – Occiput
• C3 – Back of neck
• C4 – Trapezius
• C5 – Deltoid patch
• C6 – Thumb
• C7 – Middle finger
• C8 – Pinky
• T1 – Medial elbow
• T2 – Axilla
• T3 – T9 – Chest/upper abdomen

• T10 – Umbilicus
• L1 – Underpants
• L2 – Anterior upper thigh
• L3 – Knee
• L4 – Medial calf
• L5 – Lateral calf
• S1 – Lateral sole of foot
• S2 – Back of thigh
• S3/4/5/6/Coccygeal – Perianal region

Cauda equina syndrome

• Actually peripheral nerve injuries as spinal cord ends at L1
• Bowel/bladder dysfunction, decreased rectal tone, saddle anaesthesia, variable motor/sensory loss in lower limbs, reduced lower limb deep tendon reflexes and sciatica
• Bowel/bladder incontinence is not universal
• Requires MRI if suspicion exists

Neurogenic shock

• Distributive shock seen in 20% of spinal cord injuries
• Any lesion above T6 can lead to this
• Loss of peripheral sympathetic innervation leads to profound vasodilation
• If injury above T1-4: Loss of sympathetic innervation to the heart causes unopposed vagal stimulation and bradycardia (or at least absence of reflex tachycardia)
  • 16% of patients with this will suffer aystolic cardiac arrest (often triggered by tracheal suctioning)
  • Can pre-treat with atropine to prevent this
• Generally warm, peripherally vasodilated and hypotensive, with relative bradycardia
• Usually well tolerated due to adequate peripheral blood flow but ultimately can lead to hypothermia
• Need to rule out other causes of hypotension before putting down to this
• Manage with fluids +- vasopressors

Spinal shock

• Temporary loss or depression of spinal reflex activity that occurs below a complete or incomplete spinal cord injury
• – Flaccidity, loss of reflexes and loss of voluntary movemement
• The lower the level of spinal cord injury, the more likely loss of distal reflexes will occur
• Does not occur with injuries below spinal cord (i.e. below L2) so if present with lower lumbar pathology = cauda equina
• Can cause incomplete injury to appear like a complete one
• Delayed plantar and bulbocavernosus reflexes are the first to return
• Generally lasts days to weeks but can be months
• Typically lasts 48 hours

Priapism

• Due to loss of sympathetic outflow to pelvic vasculature resulting in high-flow priapism
• Can occur in complete spinal cord injury and spinal shock
• Carries poor prognosis and suggests complete spinal cord injury but is not definite

Bulbocavernosus reflex

• Anal sphincter contraction in response to squeezing glans or tugging on Foley
• Reflex involves S1-3
• Absence suggests spinal shock and inability to determine if complete or incomplete spinal cord injury and thus limited prognostication
• If present, suggests spinal shock has resolved and can more readily determine if complete/incomplete and prognosticate accordingly

Clinical decision rules

• Head and neck trauma not fully alert all get CT (1.7-8% incidence of C-spine injury)
• NEXUS
  • Plain imaging not required if:
    • Absence of midline cervical spine tenderness
    • Normal alertness (GCS 15, oriented, remember three objects at 5 minutes, normal response to external stimuli)
    • No evidence of intoxication
    • Absence of focal neurological deficits
    • Absence of painful distracting injury (any injury with potential to impair patient’s ability to appreciate other injuries)
  • Originally 99.6% sensitive for clinically significant C-spine injuries and 12.9% specific
  • Later validation in >65yo showed 100% sensitivity and 14.7% specific
  • Only 66% sensitive vs. CT in later validation study

Clinical decision rules

• Canadian C-spine (CCR)
  • Three assessments in sequential order
  • Original study 100% sensitive and 42.5% specific for ‘clinically important’ C-spine injuries
  • One published comparision (by authors of CCR) showed CCR to be more sensitive (99% vs. 91%)

• CCR
  • 1 – No high risk factors?
    • Age >65
    • Dangerous mechanism (Fall >3ft, axial loading, high-speed mVA, rollover or ejection, motorised recreational vehicle or bicycle collision
    • Presences of peripheral paraesthesias
  • 2 – Are any low risk factors present that allow ROM testing?
    • Simple rear-end MVA?
    • Patient able to sit up in ED?
    • Ambulatory at any time?
    • Delayed onset of neck pain?
    • Absence of midline cervical tenderness?
  • 3 – Is patient able to rotate his/her neck 45 degrees each way (regardless of pain)?

• Both have now been compared to CT as the gold-standard (rather than prospectively defined ‘clinically significant’ injuries)
• NEXUS found to be 82.8% sensitive vs. CCR 100% sensitive
• NEXUS still recommended by many trauma societies
• Tintinalli states ‘Both widely validated and demonstrated adequate sensitivity so can use either’

C-spine plain radiography

• Single lateral film will identify 90% of injuries to bone and ligaments
• Adequate images includes all 7 + superior border of T1
  • May require Swimmer’s view for cervicothoracic junction
• Poor visualisation of C1/2
• Problematic in obese, elderly or extremely muscular patients, especially with C-collar on

C-spine CT

• Very useful for craniocervical and cervicothoracic junctions (where plain film falls down)
• Plain films add no further information to CT
• Cost-effective in moderate to high risk patients
• EAST recommends CT as first line

Imaging for ligamentous injury

• Typically persistent neck pain/midline tenderness, extremity paraesthesias or focal neurology despite normal plain films/CT
• Flexion/extension radiographs are often inadequate and provide no further information beyond a CT
• MRI is the imaging modality of choice, however, some authors would argue that modern MDCT scans are sufficient to detect clinically significant injuries without MRI
  • If emergent MRI is not feasible, one option is to discharge patient in a hard collar with outpatient collar in 3-5 days and if still symptomatic, can have further outpatient MRI

Thoracic and lumbar spine imaging

• EAST guidelines
  • Level 1 – When imaging is deemed necessary, CT with axial collimation should be used as this is superior to plain films in identifying thoracolumbar spine fractures
  • Level 2
    • Back pain, thoracolumbar tenderness on exam, neuro deficits, altered mental status, intoxication, distracting injuries or known/suspected high energy mechanisms should be screened for thoracolumbar spine injury with CT
    • Blunt trauma patients with known or suspected injury to the C-spine, or any other region of the spine, thorough evaluation of the entire spine by CT scan should be strongly considered due to the high incidence of spinal injury at multiple levels in this population
    • If no complaints of T/L spine pain with normal mental status, normal neurological and physical examinations, may be exluded from TL-spine injury by clinical examination alone provided that there is no suspicion for high-energy mechanism or intoxication with drugs/alcohol
  • Level 3
    • MRI should be considered in consultation with spine service for CT findings suggestive of neurological involvement and of gross neurological deficit

Concurrent spine injury imaging

• Spinal column injury at one level = 20% chance of noncontiguous second fracture at another segment
• CT the whole spine

Treatment and disposition

• Aims are to prevent secondary injury, alleviate cord compression and establish spinal stability
• Minimise movements and assume unstable until spine service consulted for all patients
• Obtain emergent consultation with spine service on all spinal column fractures or ligamentous injuries, regardless of neurological compromise
• C-spine
  • Carefully monitor for respiratory or neurological deterioration
• T/L spine
  • High risk for spinal cord or other intra-thoracic/aortic/intra-abdominal injuries
  • Anterior wedge compression fractures
    • 52% of TL spine fractures
    • If loss of vertebral height <40% may be a candidate for outpatient therapy in consultation with spine service
    • If loss of height >50% or angle between damaged vertebra and rest of spine is >25% – considered unstable
  • Also need to be certain that this is not a burst fracture (involving posterior half of vertebra)
    • Misdiagnosed in 25%
  • Chance fracture is another differential
  • Some experts recommend all compression fractures undergo CT to rule out burst/chance and pathological fractures
• Sacrum fractures
  • Transverse fractures most significant as cause injury to all or part of cauda equina
  • Longitudinal fractures may cause radiculopathy
  • If they involve the central canal, can produce bladder/bowel dysfunction
• Isolated coccyx fracture
  • Treatment is symptomatic as an outpatient

Corticosteroids

• High-dose methylprednisolone remains controversial and should not be given routinely
  • Thought to inhibit free radical-induced lipid peroxidation, increase spinal cord blood flow, increase extracellular calcium and prevent loss of potassium from injured cord
  • Crosses cell membranes more rapidly and completely than other steroids
• NASCIS group in 1990’s published three studies
  • NASCIS I, II and III were all negative studies but post-hoc review showed benefit in methylpred group if given within 8 hours of injury
• Cochrane review confirmed this benefit but also stated these patients were more likely to suffer complications such as sepsis, wound infection and delayed healing, PE, DVT, GI bleeding and death
• Latest 2013 guidelines from American Association of Neurosurgeons stated no consistent or compelling data to justify use
• Avoid in brain injured patients as worsens outcomes
• Shown no benefit in penetrating trauma either

Cardiovascular complications

• Targeting MAP 85-90 appears to result in improved neurological outcomes
• Bradycardia/asystole is extremely common following SCI above T6
  • With severe cervical SCI: Persistent bradycardia seen in 100% and transient marked bradycardia <45 in 71% of patients. Cardiac arrest occurs in 16%
  • Peaks in first week and resolves over 2-6 weeks
  • Tracheal suction in the presence of hypoxia poses greatest risk of arrest
• Autonomic dysreflexia
  • Not a problem in the acute phase but seen within 6 months of SCI above T6, after recovery from spinal shock
  • Suffer intense reflex vasoconstriction, hypertension and possible seizures and ICH
  • Symptoms include headaches, blurred vision, blushing, sweating and piloerection
  • Reflex bradycardia and reflex vasodilatation above neurological level in paraplegics
  • Normal BP in SCI is 90-100 (supine) and >130 is considered high
  • Most common cause (85%) is bladder distension
  • Mortality rate 22%
  • Much more likely in complete SCI
  • Treatment
    • Sit patient UP
    • Treat cause
      • Check IDC patent and not kinked – Irrigate if blocked with 30mL saline, draining 500mL then 250mL every 15 min to prevent rebound HTN from sudden bladder contraction
      • Treat any pain
      • Look for skin infections/painful lesions
      • If rectum full and SBP <150 – Gentle manual disimpaction
      • If rectum full and SBP >150 – Treat BP first
    • Treat BP
      • First-line: GTN 400mcg SL q5-10min (DON’T GIVE IF HAD SILDENAFIL in last 24 hours)
      • Second-line: GTN 5mg patch (DON’T GIVE IF HAD SILDENAFIL in last 24 hours
      • Third-line: Captopril 25mg SL
      • Fourth-line: IV clonidine 75-100mcg in 10mL saline slow push over 5 min OR
        IV hydralazine 5-10mg stat
    • Monitor BP for at least 4 hours

Prognosis

• Best evaluated by full neurological examination at 72 hours post-injury
• Most complete tetraplegics gain one neurological level and do not recover functional lower limb movement
• Incomplete SCI have much more recovery, and >50% of incomplete tetraplegics become ambulatory
• Significant spinal cord haemorrhage on MRI indicates very low probability of motor recovery but if <4mm, the prognosis is better

Last Updated on May 14, 2024 by Andrew Crofton