CASE 22

By: Dr. Sattam Lingawi and Dr. Alaa Al-Turkustani

HISTORY: 73-year-male patient post fall with restricted ROM at the neck.

What are your findings?

What is the differential diagnosis?

FINDINGS:

Fig. 1 sagittal, Fig. 2 coronal, & Fig. 3 axial non-enhanced CT scan of the cervical spine demonstrating straightening of the cervical spine with diffuse and extensive large anterior flowing osteophytes with calcification of the Apical / Alar ligament as well as ossification of the posterior longitudinal ligament causing spinal canal stenosis. The odontoid upper margin is well corticated.

The vertebral body heights are maintained. Disc space demonstrates early degenerative disc changes. No fracture or mal-alignment noted.

DIFFERENTIAL DIAGNOSIS:

• Odontoid tip fracture.

• Persistent ossiculumterminale.

• Osodontoitum.

• Calification of the Apical and Alar ligaments.

DIAGNOSIS:

Diffuse Idiopathic Skeletal Hyperostosis (DISH) with ossification of the posterior longitudinal ligament and the Apical/Alar ligaments.

PEARLS AND DISCUSSION:

The ossiculumterminale appears as a secondary ossification center of the dens between 3-6 years and normally fuses by 12 years. Failure of fusion results in a persistent ossiculumterminale (also called Bergmann’s ossicle or ossiculumterminale of Bergmann) and is considered a normal anatomical variant of the axis. It lies above the transverse alar ligament and is therefore considered to be stable and it very rarely causes symptoms.

Osodontoideum is an anatomic variant of the odontoid process of C2 and needs to be differentiated from persistent ossiculumterminale and from an odontoid fracture. It can be associated with atlantoaxial instability. Although it was originally thought to be a congenital lesion due to a failure of the centre of ossification of the dens to fuse with the body of C2, it may actually represent an unremembered and/or unrecognized fracture through the C2/dens growth plate before the age of 6 years. There may be associated instability and chronic symptoms.

Odontoid process fracture, also known as the peg or dens fracture occurs where there is a fracture through the odontoid process of C2.

FURTHER READING:

1. Wendy R. K. Smoker, Craniovertebral junction: Normal Anatomy, Craniometry And Congenital Anomalies. Radiographics 1994: 14:255-277

2. F. C. Lyall, J. Taylor, A. Crowther. A pictorial review of odontoid peg fractures: imaging features, classification and clinical significance. ECR 2015, C-1336