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

Clinical Characteristics of Patients with Ossification of the Posterior Longitudinal Ligament and a High OP Index: A Multicenter Cross-Sectional Study (JOSL Study)

“…In particular, OPLL can be a common cause of myelopathy. Liao et al reviewed three-dimensional CT scans for 7210 patients with degenerative cervical myelopathy and showed that the prevalence of OPLL was as high as 18% [23]. However, Fujimori et al reviewed the registry data of OPLL patients and demonstrated that the prevalence of symptomatic OPLL was less than 1% in those with radiographically detected OPLL [21], demonstrating that most cases with radiographically detectable OPLL are asymptomatic.…”

High Body Mass Index Is Associated with an Increased Risk of the Onset and Severity of Ossification of Spinal Ligaments

“…OSL is a characterized heterotopic ossification disease with multiple potential risk factors likely associated with its pathogenesis (2,3). Although several studies have explored the relationship between BMI and OSL, the results are conflicting and no definite conclusions have been obtained (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Our study integrated the existing evidence and revealed that the BMI of the OSL group was higher than that of the non-OSL group (P < 0.01), thereby indicating that a high BMI may increase the risk of OSL.…”

“…Ten studies focused on the OPLL (6,7,(9)(10)(11)(12)(14)(15)(16)(17) and four studies focused on the OLF (9,13,19,20) with respect to the types of OSL. Twelve studies containing 24,710 individuals explored the association between the BMI and onset of OSL (6,9,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), and five studies on 797 OSL patients explored the association between the BMI and severity of OSL (7)(8)(9)(10)(11). Notably, Ikeda et al (11) and Endo et al (9) both simultaneously analyzed the relationship of BMI with the onset and severity of OSL.…”

“…Notably, Ikeda et al (11) and Endo et al (9) both simultaneously analyzed the relationship of BMI with the onset and severity of OSL. Five studies with a NOS score of 7 were considered low risk (8,10,12,13,20) and ten studies with a NOS score of 6 were considered moderate (6,7,9,11,(14)(15)(16)(17)(18)(19) in terms of the risk of bias. The NOS details for each study are listed in Supplementary Table S2.…”

“…OSL typically occurs in Asians, especially the East Asian population, thereby indicating that genetic factors may play a vital role in its onset; however, many environmental factors, such as mechanical stress, metabolic disorders, gender, and age, may also contribute to the occurrence of OSL (5,6). A few researchers have recently begun to focus on the relationship of obesity or body mass index (BMI) with the onset or severity of OSL because the clinical practice has presented the susceptibility of OSL in the obese population, although the results of existing studies are contradictory (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Kobashi et al (6) showed that the BMI of the OPLL group is significantly higher than that of the non-OPLL group in both male (25.8 kg/m 2 vs. 23.3 kg/m 2 , P < 0.05) and female (25.9 kg/m 2 vs. 23.4 kg/m 2 , P < 0.05) individuals.…”