CASE 37

By: Dr. Mai Mattar, MD and Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 40-year-old psychiatric male who had a fall, after which he developed paraplegia.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

Sagittal T1 (A), T2FS (B) and sagittal reformats of a cervical spine CT (C) demonstrate an ankylosed cervical spine with a fracture through the body of C6 vertebra resulting in anterior displacement and severe cord compression and injury.

DIFFERENTIAL DIAGNOSIS:

• Vertebral body fracture in a patient with ankylosing spondylitis.

• Cord contusion/transection.

• Severe disc disease.

• TB spine.

DIAGNOSIS:

Vertebral body fracture in a patient with ankylosing spondylitis.

PEARLS AND DISCUSSION:

Ankylosing spondylitis is a rheumatological condition that is poorly understood from a physiological point of view.

It results in chronic pain and deformity as well as fracture of the axial skeleton. The chronic inflammation results in brittle minimally compliant spinal column.

Ankylosing spondylitis is a seronegative spondyloarthropathy, primarily affects the sacroiliac joints, however other large joints such as the shoulders and hips show degeneration. There is strong Association with HLA-B27.

According to the modified New York criteria, a patient can have ankylosing spondylitis with 1 clinical and 1 radiological criteria, radiographic criteria includes either unilateral or bilateral sacroiliitis. The clinical presentation should be chronic low back pain for more than 3 months relieved by exercise but not by rest.

Fractures are 4 times common in patient with ankylosing spondylitis than the general population.

Spinal cord injury can result from many causes including but not limited to dislocation, bony displacement, epidural hematoma, or disc herniation.

Spinal fractures in ankylosing spondylitis frequently result from low energy mechanism such as fall from standing height.

Most acute spinal fractures occur in the cervical spine, particularly at C5-6 and C6-7 due to the oblique facet joints. Mechanism of fractures or is due to hyperextension mechanism. Fractures in ankylosing spondylitis are highly unstable with considerable risk for neurological deficits and twice as normal mortality rate than the normal population. Therefore, there should be a low threshold for obtaining a CT and MRI.

Treatment options range from external orthosis to traction, Hallo vest placement, or surgical management of these fractures.

FURTHER READING:

1. Braun J, Sieper J. Ankylosing spondylitis. Lancet. 2007;369(9570):1379–1390. 

2. Brown MA. Progress in spondylarthritis. Progress in studies of the genetics of ankylosing spondylitis. Arthritis Research & Therapy. 2009;11(5): p. 254. 

3. Sapkas G, Kateros K, Papadakis SA, et al. Surgical outcome after spinal fractures in patients with ankylosing spondylitis. BMC Musculoskeletal Disorders. 2009;10(1, article 96) 

4. Finkelstein JA, Chapman JR, Mirza S. Occult vertebral fractures in ankylosing spondylitis. Spinal Cord. 1999;37(6):444–447.