Updated: 10/5/2016

Cervical Facet Dislocations & Fractures

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https://upload.orthobullets.com/topic/2064/images/lat xray bilateral facet dislocation C4-5_moved.jpg
https://upload.orthobullets.com/topic/2064/images/Lat Xray - Unilateral facet dislocation_moved.jpg
https://upload.orthobullets.com/topic/2064/images/CT bilateral facet dislocation combined_moved.jpg
https://upload.orthobullets.com/topic/2064/images/MRI bilateral facet dislocation C5-6_moved.jpg
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Introduction
  • Represent spectrum of osteoligamentous pathology that includes
    • unilateral facet dislocation
      • most frequently missed cervical spine injury on plain xrays
      • leads to ~25% subluxation on xray
      • associated with monoradiculopathy that improves with traction
    • bilateral facet dislocation
      • leads to ~50% subluxation on xray
      • often associated with significant spinal cord injury
    • facet fractures
      • more frequently involves superior facet
      • may be unilateral or bilateral
  • Epidemiology
    • location
      • ~75% of all facet dislocations occur within the subaxial spine (C3 to C7)
      • 17% of all injuries are fractures of C7 or dislocation at the C7-T1 junction
        • this reinforces the need to obtain radiographic visualization of the cervicothoracic junction
  • Pathophysiology
    • mechanism
      • flexion and distraction forces +/- an element of rotation
Classification
  • Descriptive classification (subaxial cervical spine injuries)
    • includes
      • compression fracture
      • burst fraction
      • flexion-distraction injury
      • facet dislocation (unilateral or bilateral)
      • facet fracture
    • more commonly used in clinical setting
  • Allen and Ferguson classification (of subaxial cervical spine injuries)
    • typically used for research and not in clinical setting
    • based solely on static radiographs and mechanisms of injury
Allen and Ferguson Classification (of subaxial spine injuries)
1. Flexion-compression
 
2. Vertical compression
 
3. Flexion-distraction Stage 1: Facet subluxation  
Stage 2: Unilateral facet dislocation
Stage 3: Bilateral facet dislocation with 50% displacement
Stage 4: Complete dislocation (100% displacement)  
4. Extension-compression    
5. Extension-distraction    
6. Lateral flexion    
 
Presentation
  • Physical exam
    • monoradiculopathy
      • seen in patients with unilateral dislocations
        • C5/6 unilateral dislocation
          • usually presents with a C6 radiculopathy
            • weakness to wrist extension
            • numbness and tingling in the thumb
        • C6/7 unilateral dislocation
          • usually presents with a C7 radiculopathy
            • weakness to triceps and wrist flexion
            • numbness in index and middle finger
    • spinal cord injury symptoms
      • seen with bilateral dislocations
      • symptoms worsen with increasing subluxation
Imaging
  • Radiographs
    • lateral shows subluxation of vertebral bodies
    • unilateral dislocations lead to ~ 25% subluxation
    • bilateral facet dislocation leads to ~ 50% subluxation on xray
    • loss of disc height might indicated retropulsed disc in canal
  • CT scan  
    • essential to demonstrate
      • bony anatomy of the injury
      • malalignment or subtle subluxation of facet 
      • facet fracture
      • associated fractures of the pedicle or lamina
  • MRI 
    • indications are controversial but include
      • acute facet dislocation in patient with altered mental status 
      • failed closed reduction and before open reduction to look for disc herniation
      • any neurologic deterioration is seen during closed reduction
    • timing
      • timing of MRI depends on severity and progression of neurologic injury
      • an MRI should always be performed prior to open reduction or surgical stabilization
        • if a disc herniation is present with compression on the spinal cord, then you must go anterior to perform a anterior cervical diskectomy
    • valuable in demonstrating
      • disc herniations
      • extent of posterior ligamentous injury
      • spinal cord compression or myelomalacia 
Treatment
  • Nonoperative
    • cervical orthosis or external immobilization (6-12 weeks)
      • indications
        • facet fractures without significant subluxation, dislocation, or kyphosis
  • Operative
    • immediate closed reduction, then MRI, then surgical stabilization 
      • indications 
        • bilateral facet dislocation with deficits in awake and cooperative patient 
        • unilateral facet dislocation with deficits in awake and cooperative patient 
      • technique
        • never perform closed reduction in patient with mental status changes
        • surgical stabilization following successful closed reduction
          • unilateral dislocations are more difficult to reduce but more stable after reduction
          • bilateral dislocation are easier to reduce (PLL torn) but less stable following reduction
          • always obtain MRI prior to surgical stabilization
            • PSF or ACDF can be performed in the absence of significant disc herniation
            • ACDF performed if significant disc herniation present
      • outcomes
        • 26% of patients will fail closed reduction and require open reduction
    • immediate MRI then open reduction surgical stabilization
      • indications
        • facet dislocations (unilateral or bilateral) in patient with mental status changes
        • patients who fail closed reduction
      • technique
        • always obtain MRI prior to open reduction and stabilization
          • if disc herniation with presence of spinal cord compression then you must use an anterior approach and do a discectomy
Techniques
  • Closed reduction
    • requirements
      • adequate anesthesia
      • sedation
      • supervision of respiratory function
      • serial cross table laterals
    • technique
      • gradually increase axial traction with the addition of weights
      • a component of cervical flexion can facilitate reduction
      • perform serial neurologic exams and plain radiographs after addition of each weight
      • abort if neurologic exam worsens and obtain immediate MRI
  • Anterior open reduction & ACDF
    • indications
      • facet dislocations reduced through closed methods with a MRI showing cervical disc herniation with significant compression on the spinal cord
      • unilateral facet dislocations that fail closed reduction with a disc herniation with significant compression on the spinal cord
    • anterior open reduction techniques
      • can be used to reduce a unilateral facet dislocation
      • reduction technique involves distracting vertebral bodies with caspar pins and then rotating the proximal pin towards the side of the dislocation
      • not effective for reducing bilateral facet dislocations
  • Posterior reduction & instrumented stabilization
    • indications
      • when unable to reduce by closed or anterior approach
      • no anterior compression of spinal cord(no disc herniation)
    • technique
      • performed with lateral mass screws
      • usually have to fuse two levels due to inadequate lateral mass purchase at level of dislocation
  • Combined anterior decompression and posterior reduction / stabilization
    • indications
      • when disc herniation present that requires decompression in patient that can not be reduced through closed or open anterior technique
    • technique
      • go anterior first, perform discectomy, position plate but only fix plate to superior vertebral body
      • this way the plate will prevent graft kick-out but still allows rotation during the posterior reduction
      • this technique eliminates the need for a second anterior procedure
 

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Questions (8)
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(OBQ12.264) A 21-year-old patient is evaluated in the trauma bay after a motor vehicle accident. He was found to have a GCS of 3 on the scene and is presently intubated. His bulbocavernosus reflex is not intact. Radiographs and representative CT scan sequences are shown in Figures A through E. What is the next best step in management? Review Topic

QID: 4624
FIGURES:
1

Closed reduction under anesthesia

14%

(568/4005)

2

Open reduction under anesthesia

10%

(394/4005)

3

Overnight monitoring

2%

(79/4005)

4

Closed reduction with internal stabilization

6%

(233/4005)

5

MRI

68%

(2712/4005)

ML 3

Select Answer to see Preferred Response

PREFERRED RESPONSE 5

(OBQ10.228) Cervical facet dislocations are characteristically caused by which of the following mechanisms of injury? Review Topic

QID: 3327
1

Flexion-compression

4%

(116/3053)

2

Vertical compression

0%

(13/3053)

3

Flexion-distraction

86%

(2640/3053)

4

Extension-compression

1%

(40/3053)

5

Extension-distraction

8%

(236/3053)

ML 1

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

(OBQ08.40) An awake and cooperative patient presents to the emergency room with the injury seen in the CT scan in Figure A. Prior to the CT scan he had an ASIA Impairment Scale of E. Upon returning from the CT scanner he has an ASIA Impairment Scale of D. What is the most appropriate first step in management? Review Topic

QID: 426
FIGURES:
1

MRI

13%

(353/2695)

2

Immediate closed reduction with cervical traction

73%

(1975/2695)

3

Immediate anterior open reduction and surgical fixation

7%

(177/2695)

4

Spinal dose steroids

3%

(92/2695)

5

Cervical immobilization, observation, and serial neurologic exams

3%

(88/2695)

ML 2

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

(OBQ11.89) A 35-year-old female is involved in a high speed motorcycle crash. Work-up reveals the presence of an open right femur fracture, and neck pain. A CT scan of the cervical spine is obtained and shows a right sided C6/7 facet dislocation. Which of the following images is most representative of this injury? Review Topic

QID: 3512
FIGURES:
1

Figure A

2%

(49/2159)

2

Figure B

18%

(397/2159)

3

Figure C

74%

(1598/2159)

4

Figure D

5%

(98/2159)

5

Figure E

0%

(3/2159)

ML 3

Select Answer to see Preferred Response

PREFERRED RESPONSE 3
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