Table 5.

The analysis of risk factors for L4/5 and L5S1 facet joints

	L4/5				L5S1
	Degeneration	No change		p value	Degeneration	No change		p value
Age (y)	26.29 ± 5.38	22.23 ± 4.24	2.278	0.027*	23.22 ± 4.82	22.67 ± 4.56	0.331	0.742
BMI	23.37 ± 0.59	22.72 ± 1.06	1.572	0.122	23.49 ± 0.81	22.67 ± 1.03	2.225	0.030*
Fixed time (m)	25.86 ± 8.86	15.72 ± 4.98	4.495	0.000*	25.56 ± 4.67	15.33 ± 5.39	5.297	0.000*
Vertebral slip (no.)			0.000	1.000			1.922	0.166
Yes	3	17			1	19
No	4	30			8	26
Facet grade pre-operation			0.614	0.852			3.569	0.389
Grade 4	1	13			1	10
Grade 3	5	27			4	17
Grade 2	1	7			3	10
Grade 1	0	0			1	8
Grade 0	0	0			0	0
Disc grade pre-operation			2.934	0.317			6.404	0.145
Grade 1	1	11			1	12
Grade 2	2	26			6	16
Grade 3	2	7			0	12
Grade 4	2	7			2	4
Grade 5	0	0			0	1

BMI, Body Mass Index

^*Test was considered statistically significant at p < 0.05