Learning Curve and Clinical Outcome of Biportal Endoscopic-Assisted Lumbar Interbody Fusion

Table 1

Patient characteristics. Statistical analysis between the two groups by chi-square test or two sample -test (VAS: Visual Analog Scale; ODI: Oswestry Disability Index; value < 0.05).

Variables		Total ()	Group A ()	Group B ()	value
Operative time (min)					≤0.001
Age (year)					0.227
Sex	M	28 (50%)	18 (32%)	10 (18%)	0.592
	F	29 (50%)	16 (28%)	13 (23%)
Operation extent (levels)	1	49 (86%)	32 (56%)	17 (30%)	0.069
	2	8 (15%)	2 (4%)	6 (11%)
Index level	L2-3	1 (2%)	1 (2%)	0 (0%)	0.080
	L3-4	10 (18%)	4 (7%)	6 (11%)
	L4-5	28 (49%)	21 (37%)	7 (12%)
	L5-S1	18 (32%)	8 (14)	10 (18%)