Imaging features of cervical spondylolysis - with emphasis on MR appearances

AIM: To describe the imaging features of cervical spondylolysis, with empha sis on magnetic resonance imaging (MRT) appearances. MATERIALS AND METHODS: The clinical and imaging features (plain radiographi c, 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 featur es in two cases with bilateral defects showed spondylolisthesis and abnorma lities of the pars and adjacent facet joints. CT demonstrated well corticat ed defects and associated spina bifida occulta in all cases. The defects we re seen in only one case on MRI but in all cases, absence of the spinous pr ocess of C6 was noted on sagittal sequences due to the spina bifida occulta . Cervical spondylolysis is an uncommon condition that must be distinguishe d from an acute fracture and diagnosed radiologically to prevent mismanagem ent. Although the defect may be difficult to identify on MRT, absence of th e spinous process on sagittal sequences should raise the suspicion of the a bnormality. (C) 1999 The Royal College of Radiologists.