Table 5.

Evaluation of degree of disc degeneration

Degree of degeneration	Grade II	Grade III	Grade IV	Grade V
Disc number	2	23	83	50
area ratio of endplate	13.89% ± 2.14%	32.23% ± 15.28%	36.93% ± 16.19%	54.24% ± 18.23%**
area ratio of sagittal	5.60% ± 2.15%	19.66% ± 9.68%	20.44% ± 11.24%	28.14% ± 9.65%**
HU value of endplate	440.30 ± 42.14	544.74 ± 157.17	560.54 ± 161.91	609.58 ± 151.46

**A significantly statistical difference between grade V degeneration and grade III/ IV (p < 0.001)