Degenerative lumbosacral
stenosis
A degenerative condition of the lumbosacral (LS) joint causing
nerve pain and dysfunction is encountered regularly in dogs.
Despite this common clinical entity, details of pathophysiology,
diagnosis, and appropriate treatment are still debatable. Terms
such as cauda equina syndrome, lumbosacral disease, lumbosacral
stenosis, and degenerative lumbosacral stenosis (DLSS) have all
been used to imply a problem within the LS region. DLSS denotes a
more specific degenerative process of the LS region and excludes
other potential causes of LS disease. Chronic repetitive motion of
the LS joint leads to accelerated degeneration in some dogs and
cats ultimately leading to nerve compression and inflammation.
Predisposition to DLSS includes abnormal joint conformation,
osteochondrosis dissecans (OCD), and long-term high activity.
Breeds affected are commonly working and performance. Signs may
include pain, reduced activity, unwillingness to climb stairs or
jump, reluctance to sit, fecal or urinary incontinence, changes in
tail carriage, "hunched" posturing, stiff/stilted or lame pelvic
limb gait, and pain on tail manipulation or direct LS palpation.
Decreased tail tone and muscle atrophy may also be present.
Diagnosis of DLSS can be challenging. Magnetic resonance (MR)
imaging has become the gold-standard in evaluating the anatomical
components of the central nervous system and is currently the best
imaging modality available for DLSS. Medical and surgical options
are available for the treatment of DLSS. Generally, patients less
affected or those with contraindications for surgery receive
medical treatment alone. This includes rest, analgesia, and
anti-inflammatory drugs. Variable results have been achieved with
non-surgical treatment. Dogs with mild clinical signs tend to
improve, but recurrence of signs recurs commonly, especially in
working dogs.
Severely affected dogs, such as those with fecal or urinary
incontinence, marked sensory or motor deficits, or dogs that do not
respond to medical management are surgical candidates. Multiple
surgical techniques have been employed to 1) decompress lumbosacral
neural elements and/or 2) distract and fuse the LS joint. Overall,
dogs more severely affected neurologically prior to surgery tend to
have a poorer prognosis. Veterinarians at TAMU have experience in
diagnosing and treating pets with DLSS.
A sagittal MRI showing a compression of nerve roots due to
protrusion of the LS intervertebral disk (arrow).