We report a 92-year-old female with ankylosing spondylitis who suffered a non-displaced cervical fracture of the C4 vertebral body as the result of a mechanical fall. A rigid cervical collar was used to maintain stability. The patient later went on to develop upper airway obstruction as a result of fracture displacement. She was emergently intubated for airway protection. To our knowledge, this is the first report of interval, acute onset upper airway obstruction caused by cervical instability following trauma and fracture in a patient with ankylosing spondylitis. This example highlights one of the potential complications of rigid cervical collar immobilization in patients with spinal instability.