Table 1.

Baseline characteristics of the patients in each group with smoking data

	Group TS	Group TLIF	p value for comparison TS versus TLIF
Number of patients	N = 53	N = 57
Gender	69.8% women	68.4% women	0.87
Age	66.9 ± 10.3 yrs	57.5 ± 13.7 yrs	<0.0001
Comorbidity (ASA categories)	2.0% ASA 1	40.4% ASA 1	<0.0001
	12.0% ASA 2	46.2% ASA 2
	86.0% ASA 3	13.5% ASA 3
Number of surgeons	N = 1	N = 4

p values marked bold are significant at p < 0.05