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Traumatic Fractures in the Ankylosed Spine 2008

General Spine

Kelley L Cline, MD,
Wendy A Cohen, MD, ASSR Member
Toby Caron, MD, Non ASSR Member
Richard Bransford, MD, Non ASSR Member
Jens Chapman, MD, Non ASSR Member
Quynh Nguyen, PA, Non ASSR Member

Scientific Poster

Exhibit Panels: 1

Purpose

Objective:
The ankylosed spine, exemplified by ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis, is at high risk of fracture with stereotypical patterns of injury. The injury patterns and imaging characteristics reflect the underlying biomechanics and pathophysiology of the spine. A review of 122 patients with traumatic injury to the ankylosed spine injury was conducted. Most injuries affected the cervical spine and were secondary to hyperextension. Because the rigid spine cannot dissipate traumatic force in the normal manner, trivial trauma is often the source of significant injury. Fractures tend to occur through the weakest section of the ankylosed spine, which is the disc space. Typically, there is instability with involvement of both anterior and posterior elements and potential disruption of the spinal canal. Patients can display a variety of neurologic symptoms, ranging from increased range of motion and new onset pain to segmental cord injury to hemisection. Complex medical and surgical management is typically mandated.

Prompt identification of fracture, essential to facilitate diagnosis and treatment, is complicated by the underlying imaging characteristics. The osseous proliferation and anatomic distortion are often distracters in acute fracture recognition. Ossification of ligaments, osteopenia and noncontiguous fractures can obscure and/or limit evaluation, particularly using standard radiographic techniques. Despite seemingly inconsequential trauma, CT with multiplanar reformatted images and MRI are essential for primary diagnosis in the high-risk population. Incomplete assessment and low suspicion of injury can result in stabilization delays and rapid deterioration of neurologic condition.

Learning points:
1. A high index of suspicion is essential in the evaluation of trauma patients with ankylosed spines, as minor trauma can result in serious injury.
2. A comprehensive understanding of traumatic force and typical radiographic injury distribution is imperative for accurate diagnosis and treatment.
3. A complete evaluation often requires CT and MRI for identification of injury, as well as evaluation of distorted anatomy and fine detail injury.