Hounsfield unit values in patients with diffuse idiopathic skeletal hyperostosis and thoracolumbar injuries - a single-center retrospective study.

PURPOSE: This study compared Hounsfield unit (HU) values on computed tomography (CT) scans at fractured sites and each vertebral level of the whole spine among three groups: individuals with diffuse idiopathic skeletal hyperostosis (DISH), young individuals without DISH, and older individuals without DISH. METHODS: A total of 71 patients with thoracolumbar fracture treated at our hospital from 2011 to 2022 were enrolled. Patients were divided into three groups: those with DISH (22 cases), young without DISH (Y non-DISH; age < 50 years, 24 cases), and older without DISH (O-non-DISH; age ≥ 50 years, 25 cases). The total spine HU values from C2 to S1 were measured from CT axial images, as follows: C2-C6, cervical spine; C7-T4, upper thoracic spine; T5-T9, lower thoracic spine; T10-L2, thoracolumbar spine; and L3-S1, lumbar spine. We compared (1) the HU values between fractured and non-fractured sites in each group (2) the HU values by site within each group, and (3) the HU values at each vertebral level of the whole spine between the three groups. RESULTS: In all groups, the mean HU values were significantly higher in the cervical spine than in the other regions (p < .05) and HU values increase at the fracture site (p < .05). The mean HU values for the lower thoracic, thoracolumbar, and lumbar spine were not significantly different in each group. The mean HU values below T6 were significantly lower in the DISH and O-non-DISH groups than in the Y-non-DISH group (p < .05). The mean HU values, except at T3, did not differ significantly between the DISH and O-non-DISH groups. CONCLUSION: Among patients with thoracolumbar injuries, spinal HU values were lower in older patients with and without DISH than in younger patients.