Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Six The Spine 699
FIG. 6-47 A 9-year-old male Spitz with paraparesis that was worse
on the right. The ventrodorsal view revealed a loss of the cortical line
of the right pedicle of L5. The left pedicle is present but less apparent
than usual (white arrows). Differential diagnoses include neoplasms
of the spine, spinal cord, or meninges. Diagnosis: Osteosarcoma of
L5.
FIG. 6-48 A 5-year-old male
Samoyed with slowly progressive
paraparesis. The lateral view of the
caudal lumbar spine revealed
erosion of the laminae of the arch of
L6. The normal cortical line is
seen clearly in L5 and L7 (black
arrows). Differential diagnoses
include primary spinal cord tumors
and primary or metastatic neoplasia
of the vertebral body. Diagnosis:
Ependymoma.
large-breed dogs. 208 There may be no radiographic changes; however, survey radiographic
findings, such as sclerosis, vertebral misalignment, sacral osteochondrosis, and spondylosis
of the lumbosacral articulation, may be identified. 207,209-211 Flexion and extension radiographs
of the lumbosacral junction may be helpful in identifying misalignment or instability,
but these changes may be present without cauda equina compression, because the
vertebral canal compression usually is associated with ligamentum flavum or dorsal longitudinal
ligament hypertrophy or disc prolapse. 212 Measurements of the lumbosacral angle
have not been useful in separating symptomatic from asymptomatic dogs. 213 Definitive
diagnosis requires myelography, lumbar sinus venography, epidurography, discography,
CT, or MRI. 11-18,213-221 Myelography with lateral radiographs that are obtained with the
lumbosacral junction flexed and extended can be used to demonstrate cauda equina compression
in those dogs in which the dural sac extends beyond the lumbosacral junction.