Clean Run - June 2015 - 12

Normal lumbosacral junction

Lumbosacral disc protrusion

junction. All of these changes individually, or in combination, lead to narrowing of
the vertebral canal and nerve compression.

Diagnosis
Physical Examination
Given the often vague nature of the signs seen with lumbosacral nerve root compression, a thorough physical, orthopedic, and neurologic exam is often vital in
pinpointing the area of concern. Orthopedic conditions such as hip osteoarthritis,
bilateral cruciate ligament injury, and groin muscle strains should be screened for
as their presentations can look quite similar to dogs with lumbosacral disease.

Subluxation (instability) of the lumbosacral junction

the diagnostic modality of choice for
identifying lumbosacral nerve root
compression. Since an MRI study takes
more time to obtain compared to radiographs or CT, during MRI scans general anesthesia is an absolute necessity.

Radiographs (X-rays)
Radiographs are a useful tool for screening for certain conditions, and are frequently recommended as an initial screening tool in dogs with low back pain given their
ease of acquiring. In particular, radiographs are useful for identifying bone conditions that can cause back pain (fractures, vertebral tumors), or infections of the
intervertebral disc (discospondolytis). Changes supportive of lumbosacral disease
may be seen radiographically such as bone proliferation, disc space collapse, or significant instability of the lumbosacral junction. However, one significant limitation
of radiographs is that they do not provide detail of the soft tissue (nerve roots, intervertebral discs), which precludes definitive diagnosis of this lumbosacral disease.
Computed Tomography (CT Scanning)
CT scans utilize similar technology to radiographs to acquire three-dimensional imaging of the area of interest. Because CT provides images in three dimensions, the
detail acquired is much higher than in with plain radiography. In particular, CT imaging is useful in screening for bone conditions that plain radiography is not sensitive enough to pick up, such as small fractures. Since CT is based on the same X-ray
technology as radiographs, it does also share the limitations in soft tissue detail.
While CT scans are relatively quick to obtain, the need for the patient to remain motionless during the scan often means that they need to be either sedated or placed
under general anesthesia.
Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging, in contrast with the above-mentioned technologies, provides excellent soft tissue detail and allows visualization of the spinal cord,
nerve roots, and intervertebral discs. It is also a three-dimensional imaging modality, allowing for pinpoint identification of areas of concern. MRI imaging is currently

Lumbosacral disc protrusion causing severe
nerve root compression

Treatment
Nonsurgical
Nonsurgical management for lumbosacral disease consists of a course (usually 4-6 weeks) of enforced rest, medications, and rehabilitation therapy.
Activity is limited to leash walks only
and movements that exacerbate the
compression (running, jumping) are
strictly discouraged. Medications can
consist of anti-inflammatory medications, pain medications, and muscle
relaxants. Low-dose oral corticosteroid
use has been extensively evaluated as
a treatment modality; while the effectiveness of the anti-inflammatory and
pain relieving effect can be greater
than non-steroidal anti-inflammatories
the adverse effects on muscle mass and

Somewhat simplistically, the vertebral column can be thought of as a tube of bone that the spinal cord
and nerve roots pass through until exiting and traveling to various parts of the body to perform their
function. Each individual vertebrae makes up a portion of this tube, and in between each vertebrae
there are intervertebral discs which function as cushions or shock absorbers.
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June 15

Clean Run - June 2015

Table of Contents for the Digital Edition of Clean Run - June 2015