Table 1.

Demographic data between groups

	Group A (n = 34)	Group B (n = 52)	Group C (n = 41)
Sex (M/F)	18/16 (47.1)	20/32 (61.5)	17/24 (58.5)
Follow-up (months)	38.3 ± 7.4	39.2 ± 11.7	34.7 ± 8.2
Comorbidity (−/+)	16/18 (52.9)	43/9 (17.3)	17/24 (58.5)
Osteoporosis (−/+)	20/14 (41.2)	46/6 (11.5)	23/18 (43.9)
Smoke (−/+)	29/5 (14.7)	38/14 (26.9)	34/7 (17.1)
Fusion level (S/M)	17/17 (50.0)	39/13 (25.0)	13/28 (68.3)
Revision (−/+)	22/12 (35.3)	26/26 (50.0)	33/8 (19.5)

Number in parentheses represents percentage of patients with risk factors for pseudoarthrosis

S single-level fusion, M multilevel fusion