Table 1.

Patient demographic data

	MiTLIF group	OTLIF group
No. of patients	42	43
Mean age (years)	47.9 ± 8.5	53.2 ± 10.6
Gender (M/F) (% male)	13/29 (30.1)	16/27 (37.2)
Preoperative diagnosis [no. (%) of patients]
Degenerative spondylolisthesis	24 (57.1)	22 (51.2)
Isthmic spondylolisthesis	18 (42.9)	21 (48.8)
Level of fusion [no. (%) of patients]
L3–L4	3 (7.1)	3 (6.9)
L4–L5	21 (50)	23 (53.5)
L5–S1	18 (42.9)	17 (39.5)