ACR APPROPRIATENESS CRITERIA
American College of Radiology (ACR) has released Appropriateness Criteria for imaging of the cervical spine in case of suspected trauma.
Different variants are presented,
dependent on the clinical and neurological status of the patient.
Common scenarios in case of suspected cervical spine trauma (positive clinical crtieria of NEXUS/CCR) include:
- Unspecific clinical status (Fig.
10)
Unenhanced CT of cervical spine should be performed.
This examination has a rating of 9 in the ACR scale (1-9) and is considered as a "usually appropriate" imaging modality.
- Patient with myelopathy, suspected traumatic spinal cord injury (Fig.
11)
CT and MRI of cervical spine are recommended (Rating 9).
- Unstable spine (imaging required for treatment planning)
(Fig.
12)
Unenhanced CT and MRI of cervical spine are "usually appropriate" examinations (CT grade 9,
and MRI 8 in the ACR rating scale)
MAIN TYPES OF FRACURES
Fractures of the cervical spine may be divided into three main types,
based on the fracture morphology:
- Compression injuries (Type A in the AOSpine classification)
- Distraction injuries (Type B in the AOSpine classification)
- Translation injuries (Type C in the AOSpine classification)
STEP-BY-STEP PROCESS FOR EVALUATION OF CERVICAL SPINE INJURIES
According to the recommendations of the AO society a step-by-step process for the evaluation of cervical spine fractures should be implemented (Fig.
1).
It is a hierarchic algorithm,
with increasing severity of injury,
from type A to type C,
where type C is the most severe injury of the subaxial cervical spine (Fig.13).
Fig. 1: Step-by-step process for evaluation of the cervical spine injury in acute setting.
Red colour indicates the most severe type of fracture (Type C fracture)
Adapted from www.aospine.org/classification
In the acute setting translation injuries (Type C) should be detected immediately and the orthopedic spine surgeon must be informed directly.
This kind of trauma may result in tetra- or paraplegia and it requires a prompt surgical treatment with stabilisation of the cervical spine.
It is the most detrimental injury and for that reason it is marked with red colour in the Figure 1.
If the type C injury is excluded,
the next step is to evaluate the anterior and poterior tension band in order to recognise type B injury (Distraction injury,
orange colour in the Figure 1. The most severe form is a hyperextension (B3) type,
and the orthopedic surgeon must be informed without any delay.
Surgical treatment is needed in case of neurological deficitis.
When the fracture does not qualify as Type B or C injury,
the compression fracture may be suspected (Type A).
A proper evaluation of the fracture morphology is required (A0-A4),
and the orthopedic surgeon should be called.
COMPRESSION INJURIES (Type A) (Fig.
14)
There are 5 morphological types of compression fractures:
A0: Minor injury (Fracture of the Spinous process,
known also as "Clay shoveler's fracture).
A1: Compression fracture with involvement of the superior endplate.
A2: Split fracture with both endplates involved.
A3: Incomplete burst fracture.
Involvement of a single endplate and posterior wall of vertebral body with fracture fragments intraspinal.
A4: Complete burst fracture.
Both endplates and posterior wall of vertebral body are involved.
Bony fragments intraspinal.
DISTRACTION INJURIES (Type B) (Fig.
15)
There are three different subtypes:
B1: Transosseous disruption with posterior tension band injury (for example a Chance fracture)
B2: As a result of hyperflexion injury.
Ligamentous disruption of the posterior tension band.
Osseous involvement is possible
B3: Hyperextension injury.
Disruption of the anterior tension band.
Posterior tension band intact.
In case of concomitant fractures of the vertebral body,
a separate injury specification (often A0-A4) is needed.
TRANSLATION INJURIES (Type C) (Fig.
16)
Only one type of fracture.
It may be associated with different injuries (type A and B)
C: Any plane displacement or translation of vertebral body/bodies in relation to the other vertebral spine segments.
The AOSpine classification distinguishes also facet injuries (type F injuries) as shown in the Figure 17.
INJURIES FROM A DAILY PRACTICE IN MULTIDISCIPLINARY EMERGENCY DEPARTMENT
Case 1:
Type B1 injury of C3/5; A1 and AO of C5; A3 of T3
Fig. 18: Sagittal CT and sagittal STIR MR images.
References: Swiss Paraplegic Centre, Nottwil, Switzerland
Postsurgical findings
Fig. 19: AP and lateral radiographs in prone position after surgical treatment with fracture stabilisation.
References: Swiss Paraplegic Centre, Nottwil, Switzerland
Case 2:
A4 injury of C7,
A2 injury (Split) of C5
Fig. 20: Sagittal and coronal CT images, 3D CT reconstruction and STIR MR images, respectively from left to right.
References: Swiss Paraplegic Centre, Nottwil, Switzerland
Case 3:
Hyperextension injury
Fig. 21: Sagittal T2w MR examination shows a hyperextension injury of C5/6.
Note the associated spinal cord injury C5/6 and extensive prevertebral hematoma.
Further hyperextension injuries are found in Figures 22 and 23.
Case 4
Translation injury
Fig. 24: Sagittal CT and T2w MR images show a translation injury of C6/7. It is a severe injury that requires prompt surgical treatment. Call your orthopedic spine surgeon immediately!
Further translation injuries are seen in Figures 25-29.
Case 5
Facet injury with perched facet joint (Typ F4 injury)
Fig. 30: Sagittal CT reconstruction demonstrate a perched facet joint of C5/6. It is a highly unstable injury, call your orthopedic surgeon immediately!
SPECIAL SITUATIONS
- Patients with ankylosing spondylitis (AS)
These patients must be approached with particular care.
Due to underlying condition and osseous changes with osteopenia,
fractures may not be clearly visible and therefore missed.
Even after a minor trauma,
if ankylosing spondylitis is known,
you should look for the fracture very carefully.
Due to multisegmental syndesmotic ankylosis,
the spine in AS in known as a "bamboo spine".
It is very fragile and can be easily fractured.
"Chalk stick" fractures occur in patients with AS and they are mostly seen in the disco-vertebral junction.
Be suspicious when a patient with AS shows up in your emergency department.
Fig. 31: Sagittal CT, T2w and STIR MR images.
Patient with known ankylosing spondylitis suffered from a minor trauma and complained of diffuse pain in the cervical spine.
CT examination was performed but was inconspicuous.
MRI was additionally recommended and revealed a fracture through the anterior and posterior columns of C6 and C7 with disc disruption.
Note the multisegmental syndesmotic ankylosis known as a "bamboo spine".
Fig. 32: Broken chalk stick to visualise the idea of a "chalk stick fracture" of the fragile spine (i.e. in patients with AS).
Fig. 33: Lateral radiographs of a patient with known AS. On the initial radiograph fracture was not reported.
A follow-up radiograph obtained several days later showed a fracture at the C6 level involving anterior and posterior columns. Hyperkyphosis deformity was evident.
Degenerative changes of the cervical spine are also a challenging factor in the evaluation of posttraumatic spine.
High level of suspicion,
careful assessment and structured reporting are good methods to help you in acute setting.
Remember that fracture complications may be detrimental to the patient health and life.
Do not miss them.
Fig. 34: Sagittal CT and T2w MR examination of degenerative cervical spine.
Patient suffered from a minor trauma and complained of focal pain in the cervical spine. CT examination was performed and showed no suspicious findings for a traumatic injury. Additional MRI revealed a traumatic disc injury of C3/4 and spinal cord compression and focal signal change.
- Various other fractures you can see in the emergency department...
- Gunshot injury (Fig.
35)
- Cervical spine injury in a child (Fig.
36)
- Sports injury (Fig.
37)
- Traumatic disc herniation (Fig.
38)