Table 1 General information and preoperative and intraoperative parameters of natural pressure drainage group and negative pressure drainage group

Age, year

54.72 ± 11.63

52.56 ± 10.76

0.106^a

Gender

0.051^c

 Male

73

59

 Female

65

84

Height, cm

167.67 ± 7.80

166.31 ± 7.43

0.102^b

Weight, kg

67.41 ± 10.89

67.81 ± 11.15

0.431^b

Body Mass Index (BMI)

23.88 ± 3.00

24.49 ± 3.19

0.054^b

Disease types

0.752^c

 Spondylolisthesis

19

21

 Lumbar spinal stenosis

90

97

 Lumbar disc herniation with lumbar instability

29

25

 Degenerative scoliosis

0

0

Blood pressure on the day of surgery, mmHg

127 ± 14 / 81 ± 10

127 ± 15 / 82 ± 10

0.994 / 0.792^b

Preoperative albumin, g·L^− 1

40.88 ± 3.23

41.25 ± 3.16

0.164^b

Preoperative hemoglobin, g·L^− 1

146.66 ± 15.93

145.10 ± 15.74

0.411^a

Preoperative platelets, 10⁹·L^− 1

223.88 ± 50.01

228.56 ± 52.16

0.599^b

Preoperative prothrombin time, s

11.20 ± 0.86

11.06 ± 0.74

0.215^b

Intraoperative blood loss, ml

386.59 ± 82.73

387.41 ± 100.60

0.861^b