Complications of a Unilateral Nondisplaced Cervical Facet Fracture in a Patient With Previously Noninstrumented Anterior Cervical Fusion.

Fused motion segments have been documented to alter the biomechanics of the cervical spine and compromise its stability. Current literature describes a growing association between the presence of prior noninstrumented fused cervical segments and the predisposition to acute, traumatic instability at adjacent levels. We present the case of a stable cervical spine fracture pattern in a patient with a history of multilevel noninstrumented anterior cervical spine fusion-initially presenting as a small, nondisplaced unilateral facet fracture that ultimately progressed to overt displacement with kyphosis resulting in acute cervical pain and instability. The patient underwent urgent open reduction and instrumented posterior fixation. We discuss the challenges associated with a timely diagnosis and offer insight into the surgical management of this rare yet potentially catastrophic complication.