Table 4. Paired t-test comparing post-operative outcome score to pre-operative score.

	Paired differences
	Mean	Std. deviation	Std. error mean	95% confidence interval of the difference	t	df	Sig. (2-tailed)
GPi (Post) - GPi (Pre)	20.78538	17.44097	4.83726	10.24591–31.32486	4.297	12	0.001
Step score (Post) - step score (Pre)	4.94231	4.86715	1.3499	2.00112–7.88349	3.661	12	0.003
Gait velocity score (Post) - gait velocity score (Pre)	5.74074	6.60292	1.83132	1.75064–9.73084	3.135	12	0.009
Step length score (Post) - step length score (Pre)	3.94872	4.25103	1.17902	1.37985–6.51759	3.349	12	0.006
Posture score (Post) - posture score (Pre)	6.154	6.743	1.87	2.079–10.229	3.29	12	0.006
ODI (Post) - ODI (Pre)	−18.615	16.681	4.626	−28.696 to −8.535	−4.024	12	0.002

Post, post-op; Pre, pre-op; GPi, Gait Posture index.