Operative Treatment of Facet Fractures/Dislocations

Case Presentation

A 27-year-old status post motor vehicle accident who presented to the emergency department with C4-C5 unilateral (left) facet dislocation and American Spinal Injury Association D spinal cord injury (SCI) (Figures 31-1 and 31-2).

Figure 31-1 ▪ CT scan sagittal cuts. A (left sagittal), A left-sided C4-C5 facet dislocation. B (midsagittal), Listhesis and slippage of C4 on C5 indicative of a dislocation type injury. C (right sagittal), No dislocation but subluxation of the C4-C5 joint can be visualized.

Figure 31-2 ▪ MRI sagittal cuts. A, T2 midsagittal, which reveals injury to the ligamentum flavum and disk as well as hematoma extending posteriorly between the PLL and C4 vertebral body. B, Short tau inversion recovery image, which confirms the injuries to the soft tissue structures on T2 and demonstrates cord signal.

Indications for Closed Reduction

Cervical facet fracture dislocation with associated neurologic deficits in a patient who is awake and alert and able to cooperate
- Complete SCI in an awake patient
- Incomplete SCI in an awake patient
- Cervical radiculopathy in an awake patient
MRI may or may not be necessary prior to reduction depending on patient mental status/cooperation, fracture pattern, and neurologic status.

Contraindications for Closed Reduction

Patients who are obtunded or intubated
Patients without neurologic deficits
Skull fractures or intracranial hematomas may require consultation with neurosurgery prior to attempted reduction.
Inability to assess reduction on imaging (eg, large body habitus)

Techniques for Closed Reduction

Gardner-Wells tongs
- Can be done supine at bedside or on operating room table prior to open reduction attempt
  - We recommend using a pillow/sheet underneath the head as well as a roll underneath the shoulders.
  - Using a pulley system off the head of the bed that can change flexion/extension moment is also recommended to help assist with reduction (eg, bivector traction).
    - Having placed the patient on a shoulder roll and support underneath the head allows for a change in flexion/extension moment as needed for reduction.
      - Adding more pillows or sheets underneath the head can create an extension moment.
      - Removing the pillow/sheet from the head allows for a flexion moment.
    - Placing the bed in slight reverse Trendelenburg may help prevent the patient from sliding toward the head of the bed once weight is applied.
      - Taping the shoulders to the bed can also be used to apply countertraction.
  - Need to be able to visualize the dislocated level clearly with fluoroscopy prior to reduction attempt
  - Obtain a thorough neurologic examination prior to applying any traction.
  - Apply Gardner-Wells tongs as described in the chapter on tong application (halo ring traction may be used as an alternative).
    - Position pins in line with external auditory meatus just above the auricle.
    - Check that pins are evenly placed in terms of anterior/posterior translation and height above the ears.
    - Make sure that the hook on the tongs for the rope is facing up when the patient is supine.
    - One pin should have a pressure gauge—tighten so that indicator pin is 1 mm proud from the outer ring (this equals about 30 lb of force).
  - Apply 20 lb of weight initially, increasing in increments of 10 lb every few minutes.
    - Reduction should be assessed with fluoroscopy with every 10 lb added.
    - Neurologic examination should be reassessed periodically to ensure no worsening deficits.
    - Weight should be added until reduction is achieved. Maximum weight may be limited by overdistraction or when maximum tolerable tension with skull fixation or the pulley system is reached (Figure 31-3).
- Can be used as an adjunct during an open anterior procedure to help provide distraction during one of the anterior reduction methods described later.

Figure 31-3 ▪ Maximum weight may be limited by overdistraction or when maximum tolerable tension with skull fixation or the pulley system is reached.

Indications for Operative Management

Unilateral or bilateral facet dislocations
- Unilateral facet dislocations with worse outcomes when treated nonoperatively¹
Irreducible dislocation—failed closed reduction
Inability/contraindication to perform closed reduction (eg, obtunded)
Successful closed reduction requires operative management due to inherent instability of injury.

Radiologic Assessment

X-ray
- Initial assessment at institutions without quick accessibility to CT scan
- Subluxation
  - 25% with unilateral facet dislocation
  - 50% associated with bilateral facet dislocation²
- Help assess closed reductions.
- May be difficult to delineate details of a dislocation
CT scan
- Assess bony nature of injury.
  - Can help determine if there are associated fractures
  - Confirm whether dislocation is unilateral/bilateral.
- Can be used to template and measure appropriate implants
  - Lateral mass screws, interbody graft size, anterior plate size, and screws
- Assess for possible noncontiguous injuries.
MRI
- Assess for neurologic compression and signal change.
- Assess for injury to diskoligamentous complex.
- Assess for disk herniation potentially causing compression.³
- Assess for possible noncontiguous injuries.