Imaging features of cervical spondylolysis--with emphasis on MR appearances.

AIM: To describe the imaging features of cervical spondylolysis, with emphasis on magnetic resonance imaging (MRI) appearances.

MATERIALS AND METHODS: The clinical and imaging features (plain radiographic, CT and MRI) of three patients with cervical spondylolysis were reviewed.

RESULTS AND CONCLUSIONS: Three cases of C6 cervical spondylolysis have been described and the world literature reviewed. The plain radiographic features in two cases with bilateral defects showed spondylolisthesis and abnormalities of the pars and adjacent facet joints. CT demonstrated well corticated defects and associated spina bifida occulta in all cases. The defects were seen in only one case on MRI but in all cases, absence of the spinous process of C6 was noted on sagittal sequences due to the spina bifida occulta. Cervical spondylolysis is an uncommon condition that must be distinguished from an acute fracture and diagnosed radiologically to prevent mismanagement. Although the defect may be difficult to identify on MRI, absence of the spinous process on sagittal sequences should raise the suspicion of the abnormality.