Table 3.

Comparison of the stability of segments between pre and post operation (χ ± s)

Group	AD			HD
	Pre	Post	Statistic analyses	Pre	Post	Statistic
PCD	6.54 ± 1.63	6.63 ± 1.72	T = 1.232, P = 0.221	1.95 ± 0.71	1.90 ± 0.71	T = 0.827, P = 0.410
PCN	6.40 ± 1.64	6.56 ± 1.75	T = 1.429, P = 0.159	1.98 ± 0.86	2.04 ± 0.87	T = 0.579, P = 0.565
PCDN	6.81 ± 1.55	7.02 ± 1.60	T = −1.645, P = 0.117	2.22 ± 0.89	2.10 ± 0.83	T = 0.904, P = 0.378