Characteristics and standards of severe sagittal imbalance in adult patients with spinal deformities: a retrospective analysis

Table 4 Signal intensity and fatty infiltration in back muscle

	Mild (n = 35)	Moderate (n = 38)	Severe (n = 29)	P value
	Mild (n = 35)	Moderate (n = 38)	Severe (n = 29)	I vs II	I vs III	II vs III
Mean of signal intensity
L1-L2	204.7 ± 60.9	276.5 ± 205.6	538.2 ± 280.5	0.631	< 0.001*	0.004*
L2-L3	228.0 ± 75.7	299.7 ± 215.3	547.9 ± 289.9	0.657	< 0.001*	0.010*
L3-L4	233.8 ± 75.1	297.4 ± 238.0	499.1 ± 234.8	0.681	0.003*	0.028*
L4-L5	228.9 ± 77.6	303.9 ± 213.9	521.9 ± 233.6	0.556	< 0.001*	0.011*
Mean L1-L5	223.8 ± 67.6	294.4 ± 214.7	533.4 ± 237.5	0.609	0.002*	0.008*
SD of signal intensity
L1-L2	109.1 ± 31.1	168.9 ± 115.9	311.5 ± 158.1	0.369	< 0.001*	0.014*
L2-L3	130.4 ± 45.5	181.8 ± 121.9	316.8 ± 157.2	0.495	0.002*	0.018*
L3-L4	147.2 ± 50.5	185.5 ± 139.8	315.5 ± 138.7	0.673	< 0.001*	0.012*
L4-L5	141.0 ± 43.5	183.3 ± 127.6	306.3 ± 133.7	0.576	< 0.001*	0.014*
Mean L1-L5	131.9 ± 41.3	179.9 ± 124.8	312.5 ± 142.4	0.581	0.003*	0.028*
Percentage of fat infiltration (%)
L1-L2	21.54 ± 15.4	19.3 ± 10.0	31.0 ± 7.1	0.913	0.041*	0.027*
L2-L3	21.0 ± 12.8	21.9 ± 12.2	31.6 ± 6.5	0.972	0.038*	0.043*
L3-L4	25.0 ± 12.0	21.9 ± 13.5	37.1 ± 8.2	0.765	0.022*	0.003*
L4-L5	24.5 ± 12.1	23.3 ± 11.3	41.3 ± 7.2	0.851	0.003*	0.002*
Mean L1-L5	22.9 ± 11.9	21.6 ± 10.6	35.2 ± 5.4	0.873	0.005*	0.002*
Relative cross-sectional area
L1-L2	1.04 ± 0.17	0.95 ± 0.22	0.84 ± 0.30	0.570	0.337	0.440
L2-L3	0.99 ± 0.19	0.92 ± 0.19	0.80 ± 0.27	0.640	0.293	0.315
L3-L4	0.93 ± 0.24	0.83 ± 0.17	0.85 ± 0.26	0.454	0.472	0.955
L4-L5	0.97 ± 0.26	0.77 ± 0.24	0.78 ± 0.15	0.370	0.381	0.932
Mean L1-L5	0.98 ± 0.16	0.87 ± 0.15	0.81 ± 0.23	0.454	0.363	0.560

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