Os odontoideum: a significant radiographic finding

Abstract

Os odontoideum can lead to instability of the atlantoaxial joint and places the spinal cord at significant risk for acute catastrophic events after minor trauma or chronic neurological change. We present two cases of os odontoideum in pediatric patients that were not appreciated at earlier remote imaging but were, in retrospect, detectable. One patient presented with an acute spinal cord injury. Incorporating assessment of dens integrity into the evaluation algorithm for all pediatric cervical spine studies should lead to early detection of os odontoideum lesions and allow referral to appropriate clinical spinal services for evaluation, surveillance and possible surgery to prevent future complications.

Acute traumatic cervical cord injury in patients with os odontoideum

“…11,12 A delay in diagnosis is not uncommon because patients are often asymptomatic or the injury appears subtle in the absence of a cervical spine radiograph. 13 Of our 10 patients, three were asymptomatic, four reported neck pain, two had unsteadiness, and one experienced dizziness. However, none of the patients had cervical spine radiographs performed before the trauma that demonstrated os odontoideum.…”

Os Odontoideum: Review Article

“…In dystopic OO, the ossicle may fuse with the clivus at the basion. 106 Most of the reported cases of OO are of the orthotopic type. In only 22 out of the 134 cases reported by Menezes, was the mention of the fusion of the os to the clivus.…”

“…106 ( Figure 1). In the orthotopic type, flexion-extension radiographs may demonstrate that the os moves independently and relative to the axis.…”

Treatment strategies for severe C1C2 luxation due to congenital os odontoideum causing tetraplegia

“…An evidence-based treatment standard does not exist; however, different expert opinions based on multiple case reports are available. Asymptomatic os odontoideum with or without instability in flexion/extension X-rays can result in a long-term asymptomatic course [9,20] or late neurological deterioration with or without trauma [4,7,9,12]. Some authors recommend no treatment in asymptomatic or radiographic stable asymptomatic courses [9,20].…”