Table 3.

Characteristics of patients with degenerative spondylolisthesis who underwent additional surgery at the adjacent level after L4–5 decompression and fusion compared with patients who required no additional surgery at the adjacent level

	Reoperation at 1st adjacent level (L3–4)
	Yes	No
Parameter	n = 130	n = 1,208	p-value
Mean age (SD)	63 (8.9)	65 (9.5)	< 0.01
BMI (SD)	27 (4.0)	27 (4.6)	0.8
Women, n (%)	103 (80)	924 (76.5)	0.5
Fusion method, n (%)			0.2
PLF	112 (86)	1101 (91.1)
PLIF	8 (6)	47 (3.9)
TLIF	10 (8)	60 (5.0)