Table 4.

The adjacent segment disc degeneration

	L1–2	L2–3	L3–4	L5–S1
Rigid fusion
Pre-op grades	2.14 ± 0.83	2.33 ± 0.93	2.42 ± 0.84	2.53 ± 0.84
Progress	0.19 ± 0.4	0.36 ± 0.49	0.31 ± 0.47	0.19 ± 0.4
Dynamic stabilization
Pre-op grades	2.12 ± 0.9	2.49 ± 0.87	2.56 ± 0.78	2.78 ± 0.99
Progress	0.02 ± 0.16†	0.02 ± 0.16†††	0.12 ± 0.33†	0.05 ± 0.22†

Compared preoperative disc degeneration grades between rigid fusion and dynamic stabilization * p < 0.05, ** p < 0.01, *** p < 0.001

Compared progress of disc degeneration between rigid fusion and dynamic stabilization ^†p < 0.05, ^†† p < 0.01, ^††† p < 0.001