Subchondral cysts of the atlantoaxial joint: a risk factor for odontoid fractures in the elderly

Background contextScholars have postulated that cervical degeneration can predispose the upper cervical spine to injury after minor trauma. Subchondral cysts have previously been recognized as potentiators of fracture in the hip and knee but no cases of cervical degenerative cysts contributing to fracture have been reported.PurposeThis report documents a case series in which patients sustained significant injury to the upper cervical spine in the setting of subchondral cervical cysts.Study design/settingCase series/academic level I trauma center.MethodsBetween 2004 and 2008, six patients (ages 73–91 years) with cervical pathology were admitted to the trauma service at our Level I trauma center. The most common mechanism of injury was a low velocity fall, which occurred in 5 out of 6 patients. All patients suffered an odontoid fracture. In all cases, there was radiographic evidence of cyst formation, and computed tomographic imaging demonstrated fracture communication with the subchondral cyst.ResultsOf the six cases, four were treated definitively with immobilization in a cervical orthosis and two required surgery. One patient was treated with an occipital-cervical fusion, whereas the other underwent Brooks wiring. All patients ultimately went on to heal their fractures.ConclusionsDegenerative changes in the cervical spine have previously been recognized to potentiate injury. This report raises the question of whether degenerative processes at the C1–C2 articulation predispose elderly patients to injury at this level. The presence of cystic degeneration at the atlantoaxial joint should be recognized as a potential risk factor for cervical injury after relatively minor trauma.