Atypical vertebral body stress fracture in the setting of diffuse idiopathic skeletal hyperostosis

Abstract

Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory arthritis characterized by bridging ossification along the anterolateral spine. Bridging osteophytes in DISH can result in fusion, altering the biomechanics and increasing the risk of unstable spinal fractures. This report details two cases of unusual vertebral body stress fractures in the setting of DISH: a T6 fracture in a 76-year-old male presenting without definite precedent trauma, and an L2 fracture in an 82-year-old female associated with 1 month of prodromal lower back pain radiating to the groin. CT and MR imaging for both patients demonstrated incomplete fractures arising from the midportion of the anterior vertebral body, rounded sclerosis bordering the fracture site as would be seen in a stress fracture, and a marrow edema sign within the vertebral bodies. We propose that these fractures are a subacute atypical vertebral body stress fracture in the setting of DISH that, to our knowledge, has not previously been reported in the literature. It remains unclear whether the fractures detailed in this report are at risk of progressing to complete fractures, potentially resulting in spinal instability. The subacute fracture pattern described in this report should be recognized by radiologists on CT and MR imaging to avoid the potentially devastating consequences of progression to complete fracture and neurologic injury.

Keywords: Atypical fracture pattern; Biomechanics; CT and MR imaging; Diffuse idiopathic skeletal hyperostosis (DISH); Spinal fusion; Vertebral body stress fracture.