Table 1 Baseline characteristics of all patients enrolled, BMI: Body Mass Index; ASA: American Society of Anesthesiologists, VAS: visual analogue scale [10]; ADL: Activity of Daily Living Scale [11], ODI: The Oswestry Disability Index [12], USD: US Dollar

Age

57.60 ± 13.55

Sex (male/female)

156/147

BMI ( kg/m²)

23.66 ± 3.92

ASA grade (1/2/3)

153/124/26

Hemoglobin (preop) (g/L)

133.95 ± 17.97

Albumin (preop) (g/L)

41.25 ± 4.06

Surgical duration (min)

191.02 ± 50.19

Blood Loss (ml)

211.98 ± 121.42

Wound length (cm)

8.82 ± 2.87

Ambulatory time interval (d)

5.39 ± 2.65

LOS (d)

11.47 ± 5.64

Total expenses [USD]

10,434.43 ± 2995.71

Commodities

 Hypertension

75

 Diabetes

23

 Cardiac coronary disease

7

  ODI scale (preop)

49.42 ± 8.71

  ADL scale (preop)

58.40 ± 6.73

  VAS value (preop)

6.01 ± 1.41

Primary Disease

 spinal stenosis

200

 lumbar disc herniation

75

 lumbar instability

28