Table 1.

Demographic data of the patients

	OLIF51	TLIF51
Number of patients	74	74
Sex ratio (male : female)	20 : 54	24 : 50
Follow up period (months)	12.1 (5–15)*	22.3 (9–32)
Mean age (years)	64.1±9.3	66.4±10.6
Bone mineral density (T-score)	-1.5±1.1	-1.3±1.4
Cage parameter
Mean height (mm)	12.4±1.5*	10.6±1.7
Footprint size (mm×mm)	30×24*	10×32
Mean angle (°)	11.2±1.6*	0.0±0.0
Pathology at the L5–S1 level
Central stenosis	7	10
Foraminal stenosis	67	74
Operation at the L5–S1 level only
Number of patients	17	27
Estimated blood volume (mL)	92.0±41.8†	217.5±153.7
Operation time (minutes)	167.7±24.9	164.7±21.2

^*p<0.001 comparing to TLIF51.

^†p<0.05 comparing to TLIF51.

OLIF51 : oblique lateral interbody fusion at L5–S1 level, TLIF51 : transforaminal lumbar interbody fusion at L5–S1 level