Unstable C-spine injury with normal C-spine radiographs

Abstract

There is some controversy surrounding the optimal mode of imaging in trauma patients with suspected cervical (C) spine injury. Various rules (most notably the Canadian C-spine rules and the NEXUS rules) have been designed to help reduce the need for imaging given the poor yield. Some authorities advocate CT for almost all cases whereas others advocate three view radiographs unless the patient is at high risk, in which case CT is the preferred choice. One meta-analysis showed sensitivity of 58% (39–76%) for plain radiographs and 98% for CT in identification of C-spine injuries following blunt trauma. This case report illustrates how very unstable C-spine injuries may not be apparent on plain radiographs and a degree of clinical suspicion may be required for further imaging.

Background

A potentially very unstable cervical (C) spine injury could have been missed on plain radiographs. The only reason for CT in this case was some evidence of neurological deficit. If there is clinical suspicion that a C-spine injury may be present it is important to progress to CT even if the initial plain radiographs look normal.

Case presentation

A 79-year-old man presented to the emergency department with severe neck pain and stiffness after a frontal impact in a road traffic collision at approximately 30 mph. Initial examination found evidence of soft tissue swelling and tenderness at the lower cervical spine. Adequate C-spine radiographs in three views (anteroposterior, lateral and peg view) showed no evidence of bony injury, soft tissue swelling or malalignment (figure 1). After having plain radiographs the patient developed bilateral parasthesiae in the extremities of both upper limbs. Therefore, the C-spine could not be cleared clinically.

Figure 1.

Lateral radiograph of cervical spine showing no obvious bony abnormality.

Investigations

A CT scan of his C-spine revealed evidence of an unstable fracture at the C3/4 level. The CT showed an anterior superior fracture of the C4 vertebrae extending laterally through the anterior cortex of the transverse foramen, widening of the distance between C3 and C4 spinous processes, avulsion of the spinous process and abnormal alignment of the left C3/4 facet joint (figures 2 and 3). The patient was immobilised in an Aspen collar, transferred to the spinal injuries unit and had further imaging in the form of MRI. The MRI showed a shallow prevertebral haematoma extending from C1 to C5, impingement of the cord at C3/C4, a severe narrowing of both C4 neural exit foramina with likely nerve root impingement and narrowing of exit foramina at levels C6-T1 (figure 4). Management involved skull traction to disengage the facet dislocation at C3/4 and anterior discectomy and fusion at C3/4.

Figure 2.

CT scan showing unstable C3/C4 fractures.

Figure 3.

CT scan showing unstable C3/C4 C-spine fractures.

Figure 4.

MRI showing significant haematoma and cord impingement at C3/C4.

Outcome and follow-up

The patient had neurological defects postsurgery which made him initially dependent on a wheelchair. After rehabilitation, he progressed to the use of a Zimmer frame. He also required a urinary catheter for the first 6 months after the initial trauma.

Discussion

Analysis of 65 published studies shows the prevalence of C-spine injury following blunt trauma to be 2.8% overall and approximately 2% in less selective, prospective studies of consecutive patients.^1–3 Less than 1% of patients will suffer a cord injury but for those that do it can be devastating to the individual and their family.

There is some controversy surrounding the optimal mode of imaging in trauma patients with suspected C-spine injury. Various rules (most notably the Canadian C-spine rules and the NEXUS rules) have been designed to help reduce the need for imaging given the poor yield.^{2 3} However, clinical suspicion of an injury still necessitates imaging. Some authorities advocate CT for almost all cases whereas others advocate 3 view radiographs unless the patient is at high risk in which case CT is the preferred choice.^4–7 One meta-analysis showed sensitivity of 58% (39–76%) for plain radiographs and 98% for CT in identification of C-spine injuries following blunt trauma.⁸ The College of Emergency Medicine advises CT as the primary imaging modality in adults following blunt trauma if:

• The Glasgow Coma Scale score is below 13 on initial assessment;

• The patient is intubated;

• Plain radiographs are inadequate;

• There is suspicion of abnormality on plain films;

• The patient is being scanned for head injury or multiregion trauma.

If high clinical suspicion of C-spine injury is present then CT may be used as the primary imaging modality.⁹

Patient's perspective.

• The patient was very happy with the management and is recovering well.

Learning points.

• Unstable cervical (C) spine injuries may not be visible on initial plain radiographs.

• The presence of degenerative changes can make it extremely difficult to rule out C-spine injures on plain radiographs.

• CT scans are significantly more sensitive than plain radiographs in identifying C-spine injuries.

• Use clinical judgement when deciding whether to progress to CT scan (even if plain radiographs are normal). Clinical signs may be subtle but the underlying injury may be potentially devastating.