A new mechanism of injury in ankylosing spondylitis: non-traumatic hyperextension causing atlantoaxial subluxation.
Ankylosing spondylitis (AS) is a progressive multisystem chronic inflammatory disorder. The hallmark of this pathological process is a progressive fusion of the zygapophyseal joints and disc spaces of the axial skeleton, leading to a rigid kyphotic deformity and positive sagittal balance. The ankylosed spine is unable to accommodate normal mechanical forces, rendering it brittle and susceptible to injury. Traumatic hyperextension injury of the cervical spine leading to atlantoaxial subluxation (AAS) in AS patients can often be fatal. We report a non-traumatic mechanism of injury in AS progressing to AAS attributable to persistent hyperextension, which resulted in fatal migration of C2 through the foramen magnum.
Department of Orthopaedics and Traumatology, University of Hong Kong, Hong Kong, SAR, China.
D
D
Samartzis
H N
HN
Modi
K M C
KM
Cheung
K D K
KD
Luk
D001268:Atlanto-Axial Joint / Q000293:injuries* / Q000473:pathology; D002574:Cervical Vertebrae / Q000473:pathology*; D017809:Fatal Outcome; D005539:Foramen Magnum; D006801:Humans; D004204:Joint Dislocations / Q000150:complications / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013117:Spinal Cord Compression / Q000150:complications / Q000209:etiology*; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000473:pathology*