Spine Flashcards
unilateral facet dislocation X-ray finding and presentation
leads to ~25% subluxation on xray
associated with monoradiculopathy that improves with traction
bilateral facet dislocation X-ray?
leads to ~50% subluxation on xray
often associated with significant spinal cord injury
Mechanism and location of cervical facet fracture and dislocation
flexion and distraction forces +/- an element of rotation
What levels do cervical facet fractures occur at most often?
~75% of all facet dislocations occurred within the subaxial spine (C3 to C7)
17% of all injuries were fractures of C7 or dislocation at the C7-T1 junction
reinforces need to radiographically visualize the cervicothoracic junction
Flexion distraction injuries of the c-spine according to Allen-ferguson have four stages, what are they?
Bonus: what ligament is intact in unilateral dislocations but not bilateral? What ligament is intact in both?
Stage 1: facet subluxation
Stage 2: unilateral facet dislocation
Stage 3: bilateral facet dislocation with 50% displacement
Stage 4: complete dislocation
PLL/ALL
Role of MRI in cervical facet dislocations after successful closed reduction, how do they guide treatment?
Surgical stabilization following successful closed reduction
PSF or ACDF can be performed in the absence of significant disc herniation
ACDF performed if significant disc herniation present
What improves cervical radiculopathy?
Shoulder abduction
Treatment of odontoid fractures in elderly.
Taken from JAAOS Hsu et al 2010
Type 1 and 3: collar
Type 2 stable: collar
Type 2 unstable: Posterior C1-2 fusion
Posterior C1-2 fusion high rate of morbidity and mortality in this age group (approx 20%) but still lower than use of a halo-vest (approx 40%).
A nonunion of type 2 is acceptable in this age group provided no s/s of myelopathy. Hence OK to treat stable 2s in a collar alone.
Treatment of odontoid fractures in non-elderly.
Taken from JAAOS Hsu et al 2010
Type 1 and 3: Collar Type 2b (Grauer modification with fracture line anterosuperior to posteroinferior): Good pattern for anterior odontoid screw.
Type 2: Low risk: Use halo-vest (or collar, but collar associated with higher nonunion rate (50% vs 30% with halo vest)
High risk: Surgical. Dealers choice of anterior screw, vs posterior C12 fixation, etc.
Risk factors for odontoid nonunion
Age >40 Posterior displacement >5mm Angulation >11 degrees Neurologic deficits Comminution of fracture
Ekong et al (from the Hsu JAAOS article 2010)
Describe harris lines and rule of 12
BAI: basion-posterior axial interval
BDI: basion-dens interval
Each should be 12 or less
List 7 ligamentous constraints of the upper C spine
Tectorial membrane (PLL)
Cruciate ligament (which includes transverse ligament)
Alar ligments (dens to condyles)
Apical ligment (dens to basion)
Nuchal ligament (external occipital protuberance to the posterior atlas and spinous processes)
Superior continuation of ALL
Superior continuation of ligamentum flavum
Outline treatment for occipital condyle fractures for types 1-3
Type 1. (comminuted condyle from compression/impaction mechanism). Stable and treat in collar
Type 2. basal skull # extending into condyle. Stable and treat in collar
Type 3. Associated with avulsion off condyle. If stable can be treating with collar. If unstable should to O-C2 fusion. Stability can be sorted out with dynamic manual traction under fluoro, or halo traction with lateral imaging. Any distraction >2mm means it’s unstable (either fracture distraction or O-C distraction.
Indications for Rigid Collar or Halo in atlas fracture
Isolated anterior or posterior ring fracture (with intact transverse ligament)
Stable burst (jefferson) ie. with combined lateral mass displacement of less than 7mm
Stable unilateral lateral mass fracture (may need MRI to sort out when transverse ligament intact to confer stability)
Indications for surgery in atlas fractures
- Plough fracture (dens driven through anterior arch of C1)
- Unstable burst (jefferson) with combined lateral mass displacement of >7mm
- Unstable unilateral lateral mass fracture (ie. transverse ligament ruptured).
If reducible in supine traction but displaces when you attach halo, can just leave them for 6 weeks in traction.
Usually Occ to C2 fusion, option to Atlas ORIF but not easy.
Levine and Edwards classification of Hangman’s #
- Bilat pars fracture minimally displaced. HALO.
1A. Unilat pars with contralateral body fracture. (side bend mechanism). HALO. - Bilateral pars # with >3mm translation
Reduce with traction/extension and use Halo vest 12 weeks. Mechanism is rebound flexion after hyperextension and axial load. Stable to apply traction. Can operate if residual displacement after reduction. C1-3 posterior or C23 ACDF.
2A. Bilateral pars # with more oblique pattern. Usually angulated moreso than translated. Associated with C23 disc and PLL disruption because mech is flexion/distraction. Interspinous ligs gone too. Very unstable (ALL is only thing intact). Reduce in extension. Do not apply traction!
Tx: HALO if reduces, if still displaced do C23 ACDF or posterior C1-3 fixation.
- Bilateral pars # with C23 facet dislocations.
Mech is hyperflexion then hyperextension. Mandatory to do posterior open reduction (won’t be able to reduce with traction). Options are C1-C3 fusion. Or preserve atlantoaxial motion by placing interfrag screws in C2 across fracture and fuse to C3.
Must use halo postop.
SLIC classification
Morphology: Compression 1 Burst 2 Distraction 3 Translation 4
Discoligamentous:
Intact 0
? 1
Disrupted 2
Neuro: Intact 0 Root involvement 1 Complete 2 Incomplete 3 Add +1 for continuous cord compression
NONOP 3 or less
4: consider for surgery
5: operative
