Prevalence of Ossification of Posterior Longitudinal Ligament in Patients With Degenerative Cervical Myelopathy

Abstract

STUDY DESIGN: A cross-sectional study. OBJECTIVE: The aim of this study was to investigate the prevalence of ossification of posterior longitudinal ligament (OPLL) in patients with degenerative cervical myelopathy (DCM). SUMMARY OF BACKGROUND DATA: OPLL of the cervical spine is one of the main entities of DCM in Asian populations. However, few studies have reported the prevalence of cervical OPLL in DCM patients. METHODS: A total of 7210 DCM patients (4546 males and 2664 females; mean age: 54 years) who underwent cervical spine three-dimensional computed tomography (3D-CT) at the Shanghai Changzheng Hospital between January 2012 and December 2016 were included in this study. Demographic data including age, sex, height, body weight, body mass index (BMI), concomitant diabetes mellitus (DM), and hypertension were recorded. The imaging diagnosis criterion for OPLL was thickness >2 mm on axial imaging. RESULTS: The overall prevalence of OPLL in the 7210 DCM patients was 18.22%, including 19.73% in males and 15.65% in females, with a significant difference between the two groups (P < 0.001). The prevalence of OPLL in DM and hypertensive patients was significantly higher than that in non-DM and normotensive patients (24.16% vs. 18.76% and 22.26% vs. 17.91%, both P < 0.001). Comparison by age and BMI showed that the prevalence of OPLL was the highest in the 70- to 79-year age group (21.91%) and obesity group (26.51%), respectively. CONCLUSION: This CT-based study revealed that the overall prevalence of OPLL in DCM patients was 18.22%. Furthermore, old age, male sex, comorbid hypertension or DM, and high BMI were risk factors for cervical OPLL. Given its high prevalence, CT examination is suggested to identify possible OPLL in DCM patients. LEVEL OF EVIDENCE: 2.