Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Six The Spine 691
Fig. 6-36 A 4-year-old male Chow Chow that
had run away was discovered by its owners as
having acute paraparesis. A, The lateral myelogram
revealed narrowing of the T12-13 disc
space and facets, a decrease in size of the neural
foramina, a ventral extradural mass at T12-13,
and a dorsal extradural mass (displacement of
the dorsal subarachnoid space ventrally) from
T11 to L2 (white arrow). B, The ventrodorsal
view revealed a right-sided extradural mass
effect from T12 to L3 that pushes the right subarachnoid
space to the left (white arrow). The
dorsal lateral mass effect extending over a space
of more than two vertebral bodies strongly suggests
extradural hemorrhage. Diagnosis:
Suspected traumatic disc extrusion at T12-13
with laceration of the right lumbar dorsal vertebral
venous sinus.
A
B
subsequently the bodies, with sclerosis or bony proliferation following the bony lysis. In
some lesions, the disc space becomes widened and irregular and in others collapse of the
disc space is observed. A sequestrum may be identified at the vertebral endplate. Several
disc spaces often are involved; however, the severity of the lesion usually varies at different
sites. During the resolution phase, disc space collapse, sclerosis, spondylosis, and sometimes
fusion of the vertebral bodies occurs (Fig. 6-37). Resolution of the bony lesion lags
behind the resolution of the clinical signs. The lesion may appear active radiographically
with increased bony lysis or proliferation and new lesions observed despite resolution of
the clinical signs. 132 In some cases diskospondylitis has been associated with a compressive
lesion of the spinal cord. 133,134