Is vertebral bone quality an independent predictor of total blood loss in transforaminal lumbar interbody fusion?

Table 4 Information on demographic characteristics of patients who had preoperative dual-energy X-ray absorptiometry scan, mean ± SD

	Subgroup	1 level	2 levels	≥ 3 levels	P value
n	71	42	24	5
Male/female	23/48	15/27	8/16	1/4	0.927
Age (year)	60.52 ± 8.46	61.40 ± 8.40	59.67 ± 8.62	57.20 ± 4.66	0.485
Hospital stays (day)	12.76 ± 3.32	12.50 ± 3.45	12.96 ± 2.77	14.00 ± 4.85	0.601
BMI (kg/m2)	26.06 ± 3.51	25.76 ± 3.06	26.43 ± 4.30	26.75 ± 3.39	0.687
Fixation segments	1.48 ± 0.63	1	2	3
Hb (preoperative, g/L)	132.30 ± 13.22	132.56 ± 15.67	132.13 ± 9.41	130.80 ± 5.45	0.959
HCT (preoperative, %)	39.56 ± 3.55	39.70 ± 4.26	39.45 ± 2.34	38.88 ± 1.48	0.874
ESR (mm/hour)	15.01 ± 10.38	16.24 ± 11.96	13.21 ± 7.67	13.40 ± 6.50	0.495
PT (second)	11.03 ± 0.65	11.05 ± 0.71	11.04 ± 0.59	10.86 ± 0.43	0.827
APTT (second)	31.68 ± 2.63	31.76 ± 2.78	31.30 ± 2.42	32.76 ± 2.33	0.506
INR	0.99 ± 0.06	1.00 ± 0.07	1.00 ± 0.07	0.97 ± 0.04	0.618
TT (second)	14.67 ± 1.00	14.57 ± 0.99	14.89 ± 0.88	14.48 ± 1.64	0.429
FIB (g/L)	3.11 ± 0.67	3.23 ± 0.72	2.88 ± 0.53	3.26 ± 0.69	0.113
D-dimer (mg/L)	0.32 ± 0.28	0.33 ± 0.31	0.31 ± 0.26	0.29 ± 0.17	0.938
PLT (109/L)	225.43 ± 47.01	224.69 ± 43.79	229.29 ± 55.04	213.00 ± 36.27	0.775
T value	-1.19 ± 1.22	-1.34 ± 1.20	-0.99 ± 1.35	-0.86 ± 0.69	0.446
Minimal T value	-2.25 ± 1.30	-2.36 ± 1.29	-2.06 ± 1.43	-2.27 ± 0.68	0.676
TBL (mL)	667.78 ± 293.78	589.09 ± 276.05	780.95 ± 295.84	785.51 ± 25.55	0.023
VBQ (L1-4median)	3.50 ± 0.50	3.57 ± 0.43	3.40 ± 0.58	3.33 ± 0.52	0.278
VBQ (L1-4 average)	3.51 ± 0.50	3.59 ± 0.46	3.41 ± 0.57	3.28 ± 0.48	0.212
VBQ (S1)	3.37 ± 0.63	3.43 ± 0.63	3.28 ± 0.67	3.25 ± 0.52	0.585
VBQ (fixation levels)	3.52 ± 0.56	3.59 ± 0.52	3.44 ± 0.63	3.34 ± 0.54	0.431

BMI: Body mass index; Hb: Hemoglobin; HCT: Hematocrit; ESR: Erythrocyte sedimentation rate; PT: Prothrombin time; APTT: Activated partial thromboplastin time; INR: International normalized ratio; TT: Thrombin time; FIB: Fibrinogen; PLT: Platelet count; TBL: Total blood loss; VBQ: Vertebral bone quality.