Assessment of cervical cord injuries
Physical Exam
- Assess for associated injury
- BP decreases in quadriplegia (Neurogenic shock), due to
- Disruption of sympathetic outflow
- Unopposed vagal tone
- Do not fluid overload
- Bradycardia / arrhythmias may be present
- May need tracheostomy if either :
- Vital capacity is less than 20% predicted
- Vital capacity is less than 1000 cc
Plain X-Ray
- Direct evidence of instability
- Increased angulation between spinous processes > 11° than in adjacent segments
- Anterior / posterior translation of the vertebral bodies > 3.5 mm
- Segmental disc space widening on lateral X-Ray
- Facet joint widening
- Malalignment of spinous processes on AP view
- Rotation of the facets on lateral view
- Tilt of vertebral body on AP view
- Findings suggestive of unstable injuries
- Increased retropharyngeal space
- Anterior to C3 : normal < 3 mm
- C4 and below : normal varies 8-10 mm
- Minimal compression fracture of anterior vertebral bodies
- Avulsion fracture at or near insertion of spinal ligaments
- Nondisplaced fracture lines
Tomography
- Good visualisation of posterior elements
- Helpful for diagnosis of dens fracture
CT
- Assesses bony encroachment on canal
- Best method for accurate bone definition
MRI
- Evaluates neural elements
- Disc disruption
- Ligamentous integrity
Stress X-Rays
- Flexion-extension lateral view
- Contraindicated in altered state of consciousness
The 3-column cervical spine
- Denis first described the 3 column spine for thoracolumbar fractures
- This 3 column concept has been extended to the cervical spine by Allen
- Each cervical motion segment can be divided into :
- Anterior
- Resists compression by vertebral body centrum, anterior disc
- Resists tension by anterior annulus, anterior longitudinal ligament
- Middle
- Resist compression by posterior vertebral body and the 2 unco-vertebral joints
- There is no significant disc material in the middle column
- Resists tension by posterior annulus, posterior longitudinal ligament
- Posterior
- Resists compression by R+L facet joints and lateral masses
- Resists tension by facet joint capsules, interspinous ligaments
Unstable Cervical Injuries
- Atlanto-occipital joint translation > 1 mm
- Apex of dens to basion > 5 mm
- Anterior translation of vertebrae > 3.5 mm
- Flexion at any one level of > 11o
- Facet joints subluxation of > 50%
- Traumatic rupture of transverse (cruciate) ligament considered, if the atlanto-dens interval is
- > 3 mm in an adult
- > 5 mm in children
- Jefferson fracture with lateral shift of the lateral masses of C1 on C2 of > 7 mm implies division of the transverse ligament allowing the two halves to separate
- Retropharyngeal soft tissue should not be
- > 3 mm at C3
- > width of the vertebral bodies below the level of C4/C5
- Unilateral facet dislocation classically leads to anterior subluxation of up to 25%, whereas bilateral dislocation results in anterior subluxation of at least 50%
Atlanto- Occipital Dislocation
- Mechanism : hyperextension and distraction
- The basion to posterior arch of C1 distance is < opisthion to anterior arch C1; if this is reversed, dislocation has occurred
- Treatment
- Often fatal
- If patient has survived, avoid traction
- Definitive treatment is fusion of occiput to C1
Transverse Ligament Rupture
- Transverse ligament is the main restraint to anterior motion of C1
- Normal distance between anterior ring of atlas and dens is < 3 mm
- Injuries may be
- Isolated
- Associated with fractured atlas
- Associated with atlanto-axial subluxation
- Mechanism : flexion
- Treatment
- If there is bony avulsion, immobilise in SOMI until healed
- Check flexion-extension views to assess transverse ligament competency
- If there is midsubstance tear, perform primary atlanto-axial fusion
Atlanto-axial Rotatory Subluxation
- Mechanism
- Presents with
- Neck pain
- Occipital neuralgia
- Vertebrobasilar insufficiency symptoms
- X-Ray
- Odontoid view shows rotator malalignment
- AP view shows C2 spine rotated off midline
- CT
- Perform in R+L rotation
- If C1 fails to reposition :
- There is a fixed deformity
- The dens separates from the anterior arch of C1 with increased rotation
- Classification : based on Atlanto-dental interval
- Type I : < 3 mm indicates intact transverse ligament
- Type II : 3-5 mm
- Failed transverse ligament
- Intact alar ligaments
- Type III : > 5 mm indicates both transverse ligament and alar ligament have failed
- Type IV : Complete posterior dislocation of atlas
- Treatment
- All symptomatic subluxations should be reduced through light weight skeletal traction
- If transverse ligament is insufficient, fuse C1 to C2 (types 2,3,4) after reduction
Atlas Fracture
- Mechanism
- Axial compression leads to forced widening of ring
- Hyperextension causes posterior arch fracture
- Classification
- Stable fractures
- Simple arch fracture
- Nondisplaced lateral mass fracture
- Fracture of TP
- Unstable fractures
- Combined overlap > 7 mm in odontoid view
- Transverse ligament is insufficient
- Treatment
- Stable fracture : hard collar for 8 weeks
- Unstable fracture : immobilise in SOMI / halo for 8 weeks
Odontoid Fracture
- Classification: (Anderson & Alonzo)
- Type I : Avulsion of the tip (avulsion fracture of alar ligament)
- Type II : Waist fracture (junction of dens with body of axis)
- 50% heal with immobilisation
- Some series have reported 20 - 80% non-union rate
- Increased risk of non union if
- Initial displacement > 5 mm
- Initial angulation >10 degrees
- Posterior vs. anterior displacement
- Age greater than 50 years
- Treatment with prolonged traction
- No halo
- Type III : Fracture into body of C2
- Treatment
- Type I : Stable
- Type II : If high risk for non-union : SOMI for 8 weeks
- Type III
- High risk for non-union, if treated with hard collar alone
- SOMI for 8 weeks
Traumatic Spondylolisthesis of C2
- Classification
- Type I
- No angulation
- Up to 3 mm of anterior translation
- Stable
- Type II
- Angulation > 10 degrees
- Anterior translation > 3 mm
- Type III
- Very unstable
- Severe angulation / displacement
- Dislocation of one or both C2-C3 facets
- Treatment
- Type I : Hard collar for 8 weeks
- Type II : SOMI for 8 weeks
- Type III :
- CR of dislocated facets may not be possible
- May need ORIF with fusion
References
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