. 2016 Sep 29;11(9):e0163452. doi: 10.1371/journal.pone.0163452

Table 1. Parameters of the operative window for each level ( $\bar{x}$ ± S, cm).

Operation window		Gender	L1-2	L2-3	L3-4	L4-5	L5-S1
Vascular window		Male	1.56 ± 0.48 (0.71–2.55)	1.24 ± 0.49 (0.00–1.93)	1.12 ± 0.48 (0.00–1.75)	1.49 ± 0.61 (0.00–2.56)
		Female	1.32 ± 0.28 (0.60–1.85)	1.13 ± 0.38 (0.00–1.78)	1.14 ± 0.32 (0.52–1.84)	1.95 ± 0.46 (0.48–2.62)
		P	0.023	0.344	0.817	0.002
Actual operation window	Bare window	Male	1.48 ± 0.75 (0.50–3.18)	1.45 ± 0.67(0.56–3.44)	1.45 ± 0.66 (0.37–3.36)	1.58 ± 0.62(0.11–3.04)	1.36 ± 1.08 (0.00–3.02)
		Female	1.31 ± 0.39 (0.65–2.41)	1.39 ± 0.47 (0.42–2.74)	1.29 ± 0.29 (0.69–2.14)	1.31 ± 0.52 (0.41–2.40)	1.81 ± 0.71 (0.00–2.91)
		P	0.261	0.694	0.234	0.078	0.066
	Psoas major window	Male	0.43 ± 0.38 (0.00–1.00)	1.03 ± 0.28 (0.36–1.64)	1.35 ± 0.34 (0.82–1.89)	0.94 ± 0.47 (0.00–1.89)
		Female	0.39 ± 0.29 (0.00–1.10)	0.69 ± 0.19 (0.32–0.99)	0.93 ± 0.20 (0.50–1.37)	0.20 ± 0.35 (0.00–1.07)
		P	0.646	0.000	0.000	0.000
Ideal operation window		Male	3.47 ± 0.23 (3.06–4.01)	3.72 ± 0.24 (3.26–4.16)	3.92 ± 0.26 (3.54–4.53)	4.01 ± 0.27 (3.70–4.65)	3.98 ± 0.33 (3.27–4.60)
		Female	3.02 ± 0.16 (2.69–3.25)	3.21 ± 0.19 (2.81–3.62)	3.36 ± 0.16 (3.08–3.66)	3.46 ± 0.18 (3.05–3.76)	3.39 ± 0.21 (2.98–3.82)
		P	0.000	0.000	0.000	0.000	0.000

Table 1. Parameters of the operative window for each level (x¯ ± S, cm).