Atypical Occipitocervical Dissociation Associated with Ossification of the Posterior Longitudinal Ligament and Diffuse Idiopathic Skeletal Hyperostosis in Low-Energy Trauma.

Introduction: Traumatic posterior occipitocervical dissociation (OCD) is a rare injury, and only a few cases have been reported in the literature. The diagnosis can be delayed or even missed because of its uncommon presentation. We present this rare case report and its management to highlight this unusual injury to increase the awareness of the existence of this pathology and prevent delayed diagnosis and treatment.

Case Report: A 76-year-old man was brought to the emergency room with complaints of neck pain. There was a history of trivial trauma before this complaint. The cervical spine images revealed an anterior subluxation of the cervical spine with Jefferson burst fracture involving bilateral fractures of anterior and posterior arches, C5-6 transdiscal fracture, underlying ossification of the posterior longitudinal ligament (OPLL), and diffuse idiopathic skeletal hyperostosis (DISH). He was managed with closed reduction, occipitocervical fourth vertebra fusion (O-C4), and C1, C2 laminectomies with a good outcome.

Conclusion: Traumatic OCD can result from low-energy trauma. We report a rare case of posterior OCD that was associated with Jefferson fracture and predisposing factors, including OPLL and DISH.