Table 1 Demographical data, anaesthetic and surgical details of 132 dogs undergoing thoracolumbar (cranial to the 1st lumbar vertebra) or lumbar (caudal to the 1st lumbar vertebra) hemilaminectomy surgery and in which a bilateral erector spinae block (group ESPB) or a fentanyl infusion (group CRI) was used. Data are reported as mean ± standard deviation or median (range). Odd ratio (OR) and 95% Confidence intervals (CI) is reported when appropriate. * indicates reciprocal OR

70 ± 34

71 ± 29

0.92

10 F (10.7%)

33 FS (35.5%)

18 M (19.4%)

32 MN (34.4%)

2 F (5.1%)

11 FS (28.2%)

8 M (20.5%)

18 MN (46.2%)

0.18

10 (3.1–38.3)

8.6 (3.9–41)

0.29

35 MFS-1 or 2 (37.6%)

53 MFS-3

(57%)

5 MFS-4

(5.4%)

31 MFS-1 or 2

(79.5%)

8 MFS-3

(20.5%)

0 MFS-4

(0%)

< 0.0001

Pre-anaesthetic medication

Methadone

(n. of dogs)

93 (100%)

39 (100%)

1

Methadone dose (mg/kg)

0.2 (0.1–0.3)

0.25

Acepromazine

(n. of dogs)

1 (1.1%)

0

1

Acepromazine (mg/kg)

0.01

Dexmedetomidine (n. of dogs)

89 (95.7%)

0

< 0.0001

Dexmedetomidine (μg/kg)

1 (0.5–2)

85 (35–240)

90 (60–150)

0.18

Induction agent

Propofol

(n. of dogs)

85 (91.4%)

39 (100%)

0.10

Propofol

(mg/kg)

2.4

(0.9–5.4)

4.2

(2.4–7.8)

< 0.0001

Alfaxalone

(n. of dogs)

8 (8.6%)

0

0.10

Alfaxalone

(mg/kg)

0.9

(0.7–1.8)

90 Isoflurane

(96.8%)

3 Sevoflurane

(3.2%)

39 Isoflurane

(100%)

0 Sevoflurane

(0%)

0.55

0.94

(0.86–1.1)

1.08

(0.91–1.19)

< 0.0001

91 extrusions

(97.8%)

2 protrusions

(2.2%)

39 extrusions

(100%)

0 protrusions

(0%)

1

51 left

(54.8%)

42 right

(45.2%)

23 left

(59%)

16 right

(41%)

0.70

80 1-disc space

(86%)

10 2-disc spaces

(10.8%)

3 3-disc spaces

(3.2%)

39 1-disc space

(100%)

0 2-disc spaces

(0%)

0 3-disc spaces

(0%)

0.01

Type of surgery

Thoracolumbar

(n. of dogs)

62

(66.7%)

21

(53.8%)

0.17

Lumbar

(n. of dogs)

31

(33.3%)

18

(46.1%)

91

(97.8%)

36

(92.3%)

0.15

3 (1–5)

4 (1–6)

< 0.0001

70 (30–150)

65 (40–110)

0.17

161 ± 43

140 ± 31

0.01