Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Six The Spine 693
Spondylitis. Spondylitis, or vertebral osteomyelitis, is infection of the vertebral body. The
radiographic changes are typified by marked periosteal new bone formation, primarily
involving the midportion of the vertebral body. Bone lysis usually is minor compared with
the proliferative response (Figs. 6-38 and 6-39). Spread to adjacent vertebral bodies is common.
This may be caused by many types of organisms including bacteria, fungi, foreign
bodies, or protozoa. 150-154 In some geographic areas (e.g., the western United States) a
common cause is plant awn migration through the respiratory tract and along the crura of
the diaphragm. 155 The second and third lumbar vertebrae frequently are involved in these
cases.
N E O P L A S I A
Primary and Metastatic Neoplasms. Both primary and metastatic tumors may affect the
vertebral column. Primary tumors may originate in the bone or in the neural tissue. 156-158
Primary bone tumors (e.g., osteosarcoma, parosteal sarcoma, chondrosarcoma, fibrosarcoma)
are the most common vertebral tumors. 159-170 Other tumors affecting bone (e.g.,
multiple myeloma, lymphoma, hemangiosarcoma, angiolipoma, metastatic tumors) have
been reported also. 158,171-176 Tumors of the nervous tissue can cause vertebral changes due
to erosion of pedicle or neural foramina.
Fig. 6-37 cont’d C, Fourteen
weeks after the first radiograph
there was complete collapse of the
disc space and marked periosteal
new bone formation around the T7-
8 interspace (open white arrow).
This series demonstrates the progression
of intradiscal osteomyelitis
(diskospondylitis) from very early
in the clinical picture to the resolution
phase. Diagnosis: Intradiscal
osteomyelitis of T7-8.
C
Fig. 6-38 A 1-year-old female
Doberman Pinscher with midthoracic
pain. On the lateral radiograph
there is marked periosteal new bone
formation involving the vertebral
bodies of T2 to T8. Also seen is the
loss of definitive vertebral shape,
decreased vertebral body density,
and possible compression fractures.
Because of the several contiguous
vertebral bodies involved, infection,
rather than neoplasia, is strongly
suggested. Diagnosis: Infectious
spondylitis of T2 to T8.