Radiologic Assessment—Key Factors to Consider on X-ray, MRI, CT
The need for operative intervention is dependent upon fracture displacement and instability.
Fractures with minimal angulation or displacement can be treated in a hard cervical collar for 6 to 12 weeks.
Displacement of more than 2 to 5 mm or angulated fractures usually require either halo reduction or operative intervention.
MRI may be useful for evaluation of the discoligamentous complex. Fractures with extension into the disk space and disruption of the posterior longitudinal ligament or disk are more unstable.
CT scans should be closely reviewed to assess for the feasibility of posterior instrumentation from C1-3, as noted in the chapter on C1-2 fixation. If the posterior bony anatomy is not amenable to fixation, the author may consider a C2-3 anterior cervical diskectomy and fusion (ACDF).
C2-3 ACDF is also preferred in cases with traumatic disk herniation with extrusion into the canal.
C2-3 ACDF is relatively contraindicated in cases with displaced fractures that do not passively reduce. Active reduction may be more amenable through a posterior approach.
Each approach will be illustrated with a case. The pros and cons of each technique are listed in Table 33-1.
Table 33-1 Considerations in the treatment of Hangman’s fractures
Technique
Pros
Cons
Collar
Used in nondisplaced (<2 mm) fractures with minimal angulation.
Not suitable for unstable injuries. Patient must be compliant with collar wear for 6-12 wk and requires close radiographic surveillance.
Halo
Used in nondisplaced (<2 mm) fractures or fractures that can be closed reduced.
Patient must be compliant with halo for 6 wk and requires close radiographic surveillance.
C2-3 ACDF
Short segment fixation, preserves motion. Less approach-related morbidity.
Less biomechanically rigid than posterior fixation. Potential dysphagia with high cervical approach. May be more difficult to reduce displaced fractures with facet involvement.
C1-3 PSF
More rigid, tension band away from the axis of rotation. Preferred in cases with multiple involved fracture levels, or in cases with fractures or instability of the facet joints that require active reduction.
Loss of C1-2 rotational motion. The C1-2 joint should be spared if possible.
C2-3 PSF or C2 pedicle lag screw
Possible if C2 fracture can be skewered by a C2 screw or if the fracture pattern and anatomy allow for a C2 pedicle screw placement.
Technically demanding, not all fracture patterns are amenable to this screw type.
A 54-year-old male presented with neck pain after a motor vehicle collision. His CT scan showed a type 2 dens fracture and bilateral C2 pars fractures (Figure 33-1). He had no neurologic deficits.
His sagittal MRI scans showed disruption of the facet capsules at C1-2 bilaterally (Figure 33-2).
Figure 33-1 ▪ Parasagittal and midsagittal CT cuts from a 54-year-old male who was in a motor vehicle collision and presented with neck pain. The fracture line extends through the base of the dens and through both pars at C2.
Figure 33-2 ▪ Parasagittal and midsagittal MRI showed disruption of the C1-2 facet joints.
His initial plain radiographs showed minimal displacement (Figure 33-3). The patient declined surgery and was placed in a hard cervical collar.
Figure 33-3 ▪ Initial standing plain radiographs showed minimal fracture displacement and the patient was placed in a collar.
One week after discharge he returned to clinic with significant anterior displacement and was indicated for surgery (Figure 33-4).
Because his injury involved the dens and the C2 pars, a construct was chosen that spanned across the entirety of the zone of injury. We thus indicated the patient for a C1-3 pedicle screw fixation (PSF).
Figure 33-4 ▪ One week after the motor vehicle collision, the patient returned to clinic with significant anterior displacement of the fracture.
Positioning
Prone in Mayfield tongs—refer the posterior cervical fusion chapter.
Great care should be taken when turning the patient, and gentle inline traction maintained during the turn. The head should initially be placed in the position consistent with fracture reduction (ie, gentle extension in this case).
After positioning, fluoroscopy is brought in to verify fracture reduction and overall alignment (Figure 33-5). Additional manipulation can be done at this time as needed under fluoroscopy.
Figure 33-5 ▪ Intraoperative fluoroscopic views after positioning in Mayfield tongs.
The canal is generally enlarged by the pars fracture, so the likelihood of cord injury is relatively lower than some other fracture types.
Greater risk may occur if there is significant instability through the C2-3 disk or a significant disk herniation.
Anesthesia/Neuromonitoring Concerns
In unstable fracture patterns, we consider obtaining a set of prepositioning baseline motor evoked potential (MEP) and somatosensory evoked potential (SSEP). These are then compared after positioning to verify that the positioning has not resulted in neurologic compromise.
Reduction Techniques
At this point, additional open reduction maneuvers can be attempted if residual displacement remains (Figure 33-6).
Figure 33-6 ▪ Retractor placement after exposure is complete.
The Mayfield can be adjusted again with the wound open while the fracture alignment is directly visualized.
If residual displacement remains, the spinous processes can be directly manipulated to allow manual reduction. Generally, the spinous process is pushed anteriorly so that the C2 pars fracture gap closes down.
Only gold members can continue reading. Log In or Register to continue
