Abstract
Objectives
To describe the ultrasonographic anatomy of the caudal lumbar spine in cats and to
detect ultrasound (US) signs associated with epidural or intrathecal injection.
Study design
Prospective, clinical study.
Animals
Twenty‐six client‐owned cats.
Methods
Transverse (position 1) and parasagittal (position 2) two‐dimensional US scanning
was performed over the caudal lumbar spine in all cats. Midline distances between
the identified structures were measured. Cats assigned to epidural injection (group
E, n = 16) were administered a bupivacaine–morphine combination confirmed by electrical
stimulation. Cats assigned to intrathecal injection (group I, n = 10) were administered a morphine–iohexol combination injected at the lumbosacral
level and confirmed by lateral radiography. The total volume injected (0.3 mL kg−1) was divided into two equal aliquots that were injected without needle repositioning,
with the US probe in positions 1 and 2, respectively. The presence or absence of a
burst of color [color flow Doppler test (CFDT)], dural sac collapse and epidural space
enlargement were registered during and after both injections.
Results
US scanning allowed measurement of the distances between the highly visible structures
inside the spinal canal. CFDT was positive for all animals in group E. In group I,
intrathecal injection was confirmed in only two animals, for which the CFDT was negative;
seven cats inadvertently and simultaneously were administered an epidural injection
and showed a positive CFDT during the second aliquot injection, and the remaining
animal was administered epidural anesthesia and was excluded from the CFDT data analysis.
Dural sac collapse and epidural space enlargement were present in all animals in which
an epidural injection was confirmed.
Conclusions and clinical relevance
US examination allowed an anatomical description of the caudal lumbar spine and real‐time
confirmation of epidural injection by observation of a positive CFDT, dural sac collapse
and epidural space enlargement.
Keywords
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Article info
Publication history
Accepted:
January 8,
2016
Received:
June 17,
2015
Identification
Copyright
© 2016 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Inc. All rights reserved.
