Fig 1.
Sagittal and dorsal CT scout images showing guide needle and spinal needle placement.
The guide needle is used to determine the site of insertion of the spinal needle on the skin. The needle is placed perpendicular to the long axis of the spine and immediately cranial to the border of the flexed stifle and directed perpendicularly. The spinal needle is placed into the vertebral canal immediately cranial to the guide needle and advanced until the tip meets the ventral surface of the spinal canal.
Fig 2.
Sagittal and dorsal scout showing a test injection and linear contrast column filling of the ventral portion of the subarachnoid space.
This indicates accurate needle placement so that the entire volume of contrast medium may then be injected. An epidural injection occurred in two instances and needle replacement resulted in correct injection into the subarachnoid space.
Fig 3.
Sagittal scout showing epidural extravasation of contrast medium.
This occurred in one pig and the needle was removed and a new spinal needle was placed a second time and a second test injection was performed and showed linear contrast columns of the subarachnoid space.
Fig 4.
Transverse CT myelogram image showing manual delineation for area measurements.
Spinal cord (SC), dural space (DS), and vertebral canal (VC). This site has the qualitative designation of C for continuous contrast filling of the subarachnoid space. C = continuous and concentric filling of the subarachnoid space.
Fig 5.
Transverse CT myelogram images showing the qualitative descriptions for contrast filling morphology.
(C = concentric, NC = Non-concentric) and presence of epidural extravasation (E = epidural extravasation), or a combination of epidural contrast and non-concentric filling (NCE) or CE for concentric with epidural extravasation.
Table 1.
Qualitative assessment of contrast filling of the subarachnoid space for each measurement at the mid vertebral body and intervertebral disc space (hyphenated).
The designation of each sow, 1–6, is listed as numbers in each column for each segment.
Table 2.
Spinal formula, body weight, spinal length, injection site, and location of the lumbar intumescence and conus medullaris of the thoracolumbar spine in 6 Yucatan sows.
Fig 6.
Graph of the vertebral canal surface area (mm2) in 6 Yucatan sows.
The median, 75th, 25th percentile and the range are shown for each thoracolumbar vertebral segment.
Fig 7.
Graph of the spinal cord surface area (mm2) in 6 Yucatan sows.
The median, 75th, 25th percentile and the range are shown for each thoracolumbar vertebral segment.
Fig 8.
Graph of the dural space surface area (mm2) in 6 Yucatan sows.
The median, 75th, 25th percentile and the range are shown for each thoracolumbar vertebral segment.
Fig 9.
Graph of the spinal cord to dural space ratio in 6 Yucatan sows.
The median, 75th, 25th percentile and the range are shown for each thoracolumbar vertebral segment.
Fig 10.
Graph of the spinal cord to vertebral canal ratio in 6 Yucatan sows.
The median, 75th, 25th percentile and the range are shown for each thoracolumbar vertebral segment.
Fig 11.
Graph of the dural space to vertebral canal ratio in 6 Yucatan sows.
The median, 75th, 25th percentile and the range are shown for each thoracolumbar vertebral segment.