Table 2. Clinical characteristics of cervical OPLL.

^*Classification by Investigation Committee on ossification of posterior longitudinal ligaments (OPLLs) of the Japanese Ministry of Public Health and Welfare, ^†Classification by C2–7 Cobb angle. Kyphosis<0°, 0°≤straight<10°, 10°≤Lordosis, ^‡Classification by compression angle. Low angle group<50°, high angle group≥50°