T11, n=2. T11/T12,n=1. T12, n=1. T12/T13, n=2. L3/L4, n=2. L4, n=2. L5, n=2. Number of vertebral segments 2.92±0.53 (2-3.5) 2.92±0.67 (1.5-3.5). Group CauL.
Comparison of two lumbar epidural catheter indwelling techniques in dogs Zhang Di, Nagahama Shotaro, Fujita Naoki, Kamata Masatoshi, Kakishima Kei, Nishimura Ryohei Laboratory of Veterinary Emergency Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo
Introduction
Caudal lumbar epidural anesthesia technique (L7/S1)
Simplicity, Safety, Effectiveness Limited to surgeries caudal to the umbilicus in dogs
Cranial lumbar epidural anesthesia technique (L1/L2, or L2/L3) Provides potent analgesia in thoracic and upper abdominal surgeries in humans --------------------------------------------- Uncommon in dogs No obvious landmarks Intervertebral space is physiologically narrow
Purpose
To compare the safety and feasibility of cranial and caudal lumbar epidural catheter indwelling techniques in dogs
Materials and Methods
Animals
Thirteen male beagles
Anesthesia protocol
Cranial lumbar vertebra group (group CraL, n=6) Caudal lumbar vertebra group (group CauL, n=6) One residual dog for a general anesthesia control
General anesthesia: isoflurane (induction and maintenance)
Epidural catheterization Euthanasia (deep anesthesia + KCL) Epidurography
Epidural catheterization
18G Tuohy needle, 20G epidural catheter
Group CraL: between L2 and L3 Group CauL: between L7 and S1
Epidural space confirmation-“loss of resistance” technique with saline Epidural catheter was advanced cephalad 10cm. Epidural injection of saline (0.2ml/kg) in single bolus.
a needle puncture
b catheter fixation
Evaluation method
Objective indexes
Success rate of catheter indwelling Time consumed for catheter indwelling process Catheter position inside of the epidural space Histological examination
Macroscopic observations (tissue color, bleeding, swelling) Microscopic observations
Subjective index-to evaluate the handling difficult degree of epidural catheter indwelling process
5 grades: Difficult; Relatively difficult; Moderate; Relatively easy; Easy
Results
In all treated dogs (n=12), epidural catheters were inserted into the epidural space successfully. Time consumed Time (sec)
Group CraL (n=6)
Group CauL (n=6)
Needle introduction 2nd introduction
90.0±39.8 3/6
74.3±16.9 1/6
Catheter insertion
44.3±10.1
57.3±18.3
Saline injection
91.7±26.5
97. 7±23.7
226.0±57.8
229.3±23.3
The whole process of epidural catheter indwelling
Catheter position and tip location Tail →
← Head
A
Group CraL
← Head
B
Tail →
Group CauL
T1 0T /T1 10/ 1T 1 1 T1 T1 1 1T /T1 T11 11/ 2T 1 T T1 12 2 2T /T1 T1 12/ 2 3T T1 13 T1 3 3 T T1 /L1 3 13/ L1 L1 L1 /LL L1 21/ L L2 2 L2 /LL L2 32/ L L3 3 L3 /LL L3 43/ L L4 4 L4 /LL L4 54 /L L5 5 L5 /LL L5 65 /L 6 L L6 6 /L L6 L76 /L 7 L L7 7 /S L7 L17 /S 1 S 1 S 1
Experiment dogs (n=12) Experiment dogs (n=12)
Group CauL
Group CraL
Parts of caudal thoracic and lumbar vertebrae
Group CraL, n=6
Group CauL, n=6
Parts of caudal thoracic and lumbar vertebrae
Predetermined epidural insertion site Actual punctured site
Catheter tip location Number of vertebral segments
L2/L3
L7/S1
L2/L3, n=1 L1/L2, n=5
L7/S1, n=3 L6/L7, n=3
T11, n=2 T11/T12,n=1 T12, n=1 T12/T13, n=2
L3/L4, n=2 L4, n=2 L5, n=2
2.92±0.53 (2-3.5)
2.92±0.67 (1.5-3.5)
Macroscopic observation
Subcutaneous bleeding
Group CraL: 3/6 Group CauL: 0/6
a
b
Tissue injuries (color change, bleeding, or swelling) of spinal cord were not detected in a control dog and in all treated dogs. d
c
Microscopic examination H.E.×40
H.E.×40
B-1
H.E ×200
B-2
A
B
No significant
histopathological changes were detected in a control dog and in all treated dogs.
H.E ×200 B-3
H.E ×200
Subjective evaluation Group CraL Group CauL Difficult
0
0
Relatively difficult
0
0
Moderate
1
0
Relatively easy
4
1
Easy
1
5
Total
n=6
n=6
Discussion
There were no significant tissue injuries of spinal cord for epidural catheter indwelling process in either group.
Cranial lumbar epidural catheter indwelling technique—relatively safe
There were no differences in time consumed for procedures of epidural needle puncture and catheter insertion between groups.
Cranial lumbar epidural catheter indwelling technique—not technically difficult
Conclusion
These results may suggest that epidural catheter indwelling technique in cranial lumbar vertebral segments is safe and feasible as well as in caudal lumbar vertebral segments at least in medium-sized dogs.
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