Review Question - QID 214135

Ankylosing Spondylitis QID: 214135 (OBQ19.233)

QID 214135 (Type "214135" in App Search)

A 78-year-old male who presents to the ED following a MVC in which he rear-ended another vehicle traveling 20 MPH. He reports a long history of chronic low back pain and neck pain for which he reports he is taking Etanercept, but denies any history of gait instability or dexterity problems with his hands prior to the accident. He denies a history of diabetes or taking blood thinner or other medications. Upon presentation he has no motor or sensory deficits, but is complaining of posterior neck pain. A radiograph taken on admission is shown in Figure A. A CT scan is subsequently obtained and negative for fracture. On tertiary exam 3 hours later, the patient is found to have severe weakness in both his upper and lower extremities. An MRI of the cervical spine is most like to show which of the following?

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Severe degenerative stenosis

12%

192/1583

Epidural hemorrhage

58%

918/1583

Vertebral artery injury

117/1583

Myelomalacia

14%

228/1583

Spinal cord infarct

119/1583

Select Answer to see Preferred Response

This patient has ankylosing spondylitis (AS), and the surgeon must maintain a high suspicion for cervical spine fractures given his mechanism and neck pain, even with a normal CT scan. With onset of new neurologic deficits, an MRI should be obtained to evaluate for fracture displacement or epidural hemorrhage.

Ankylosing spondylitis is a chronic autoimmune spondyloarthropathy with a strong association with HLA-B27. Regarding the cervical spine, patients often have ossification of the disc spaces, as shown in Figure A, which makes identification of fractures very difficult. Advanced imaging should be obtained in this subset of patients to evaluate for cervical fractures as well as epidural hemorrhage. This patient has new onset neurologic deficits and likely has an epidural hemorrhage or significant displacement of a previously unidentified fracture. Immediate MRI is crucial in this setting as the diagnosis of epidural hemorrhage carries a high mortality rate and requires operative intervention.

Colterjohn et al. reviewed the identifiable risk factors for secondary neurologic deterioration in cervical spine injured patients. They report that patients with flexural mechanisms and chronic AS were more likely to have motor neurologic deterioration after their initial evaluation. They conclude that radiographs were poorly sensitive for identifying the fractures in these patients.

Westerveld et al. review the literature on treatment and complications of spinal fractures in patients with AS. They report that the changed biomechanical properties of the spine in AS patients make them more prone to fracture and delayed neurologic deterioration. They conclude that the mortality rate following cervical spine fractures in patients with AS is 17%, which is significantly worse than the general population.

Figure A is a lateral of the cervical spine consistent with the diagnosis of ankylosing spondylitis. This is an example of a “bamboo spine”.

Incorrect Answers:
Answer 1: You would not expect rapidly progressive changes in the setting of degenerative stenosis.
Answer 3: Vertebral artery injury results in head/neck pain and dizziness, and would not be expected in this patient.
Answer 4: Myelomalacia occurs in the setting of spinal cord compression and cervical myelopathy and not following acute trauma.
Answer 5 : While spinal cord infarct may occur following trauma you would not expect to see delayed presentation of neurologic deficits.