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The Correlation Between Ossification of the Nuchal Ligament and Pathological Changes of the Cervical Spine in Patients With Cervical Spondylosis

Study Design. A retrospective clinical data analysis. Objective. This study was conducted to investigate the correlation between ossification of the nuchal ligament (ONL) and pathological changes of the cervical spine in patients with cervical spondylosis. Summary of Background Data. ONL can usually be found in cervical spondylosis. Thus, it is important to find the correlation between ONL and pathological changes of the cervical spine in patients with cervical spondylosis. Methods. The medical records of 100 patients with cervical spondylosis with the local type of ONL (ONL group) and 50 patients with cervical spondylosis only (control group) were reviewed. Data analysis included patients' sex, age, location of ONL, maximum cord compression level, osteophyte height ratio, and grade of cervical intervertebral disc degeneration. Radiological features were evaluated by lateral plain radiography and magnetic resonance imaging. Results. In total, 69.0% of subjects in the ONL group had ONL located at the maximum cord compression level; there was no difference based on sex (P = 0.248). The value of the osteophyte height ratio was higher at the ONL level than at its superior and inferior adjacent segments (P < 0.001). The osteophyte height ratio was also significantly different at the C4–C5 (P < 0.001) and C5–C6 (P = 0.008) levels between the ONL group and the control group. There was a significant difference in distribution of intervertebral disc degeneration grading between the ONL level and superior adjacent segments (P = 0.028), as well as inferior adjacent segments (P = 0.049). The distribution of intervertebral disc degeneration grading at the C5–C6 level between patients whose location of ONL and maximum cord compression level were both at C5–C6 and patients whose maximum cord compression level was at C5–C6 in the control group was also significantly different (P = 0.035). Conclusion. The location of ONL commonly corresponds to the most stenotic level of the spinal canal. The location of ONL also correlates with the level of osteophyte formation and intervertebral disc degeneration, indicating that ONL has correspondence to instability-related cervical pathological changes in cervical spondylosis. Level of Evidence: 4