Study Design: This study was a retrospective review. Objective: Bone mineral density (BMD) at the surgical site is associated with complications of surgical internal fixation, it is very important to study the cervical BMD of patients with cervical spondylosis who need surgery and the related factors that affect cervical BMD. It is still unclear whether the age-related influence of disease time, cervical alignment, and ROM on cervical vertebral Hounsfield unit (HU) value. Methods： This retrospective study was conducted on patients who underwent cervical surgery at one institution between January 2014 and December 2021. For age, sex, body mass index (BMI), disease type, comorbidities, neck pain, disease time, C2-7 cobb angle (CA), cervical range of motion and the C2-C7 vertebral HU value were recorded. The association between cervical HU value and each parameter of interest was assessed using the Pearson correlation coefficient. Multivariable linear regression analysis was performed to examine the relative influence of the multiple factors on cervical vertebral HU value. Results： Among patients younger than 50 years old, the HU value of the cervical vertebral in females was higher than that in males, but after the age of 50 years old, the female was lower than that in males and decreased significantly after 60 years old. In addition, cervical HU value was significantly correlated with the disease time, flexion CA and ROM. Our age-related subgroup of multivariate linear regression analyses that disease time and flexion CA negative affected C6-7 HU value in more than 60 years old males and in more than 50 years old females. Conclusions： Disease time and flexion CA were negative affecting the C6-7 HU values in more than 60 years old males and in more than 50 years old females. more attention should be paid to bone quality in cervical spondylosis patients with longer disease time and larger convex of flexion CA.

Study design This study was a retrospective review. Objective Bone mineral density (BMD) at the surgical site is associated with complications of surgical internal fixation, and it is very important to study the cervical BMD of patients with cervical spondylosis who need surgery and the related factors that affect cervical BMD. It is still unclear about the age-related influence of disease time, cervical alignment and range of motion (ROM) on cervical vertebral Hounsfield unit (HU) value. Methods This retrospective study was conducted on patients who underwent cervical surgery at one institution between January 2014 and December 2021. Age, sex, body mass index (BMI), disease type, comorbidities, neck pain, disease time, C2-7 Cobb angle (CA), cervical ROM and the C2-C7 vertebral HU value were recorded. The association between cervical HU value and each parameter of interest was assessed using the Pearson correlation coefficient. Multivariable linear regression analysis was performed to examine the relative influence of the multiple factors on cervical vertebral HU value. Results Among patients younger than 50 years old, the HU value of the cervical vertebral in females was higher than that of males, but after the age of 50 years, the value of females was lower than that of males and decreased significantly after 60 years old. In addition, cervical HU value was significantly correlated with the disease time, flexion CA and ROM. Our age-related subgroup of multivariate linear regression analyses shows that disease time and flexion CA negatively affected the C6-7 HU value in more than 60-year-old males and in more than 50-year-old females. Conclusions Disease time and flexion CA were negatively affecting the C6-7 HU values in more than 60-year-old males and in more than 50-year-old females. More attention should be paid to bone quality in cervical spondylosis patients with longer disease time and larger convex of flexion CA.