Disorders of the Lumbosacral Spine Flashcards
What is the cauda equina?
spinal nerve roots of the lumbosacral spine derived from L7 caudally
- shape reminiscent of a horse’s tail
What 3 things make up the lumbosacral junction/area?
- bone of L7 vertebra to sacrum
- connective tissue of L7/S1 disk, articular facets, joint capsules, and interarcurate ligaments
- cauda equina nerve roots
What is a dorsal laminectomy?
removing a small window of bone over the top of the spinal column to expose the spinal cord
What is a facetectomy?
removal of the articular facet
What is a foraminotomy?
enlargement of the intervertebral foramina to relieve pressure on nerves that are being compressed
What is the most consistent clinical sign associated with degenerative lumbosacral stenosis? What are clinical signs wrongly attributed to?
pain —> hyperesthesia
gait abnormalities can seem like degenerative changes associated with age or hip dysplasia
How do onset of clinical signs and lameness compare with degenerative lumbosacral stenosis and hip dysplasia?
DLSS - signs begin at middle-age to older, lameness worse after rest and improve with motion
HD - signs begin at younger ages, lameness worsens with activity
How do neurological deficits and pain compare with degenerative lumbosacral stenosis and hip dysplasia?
DLSS - neurological deficits present, lumbosacral and hip associated pain
HD - no neurological deficits, hip associated pain
How does response to therapy compare with degenerative lumbosacral stenosis and hip dysplasia?
DLSS - suboptimal response to NSAIDs and nutraceuticals, positive response to Gabapentin and Pregablin
HD - often responds well to NSAIDs and nutraceuticals, minimal response to Gabapentin and Pregablin
What dogs commonly present with degenerative lumbosacral stenosis AND hip dysplasia?
German Shepherds - often congenital
lumbosacral transitional vertebrae associated
- importance of Hx, PE, NE, and response to medication
What is degenerative lumbosacral stenosis? What are the most common causes?
protrusion of the soft tissue structures in the LS regions compresses cauda equina and L7 nerve roots
- anatomic abnormalities
- chronic instability
What is the pathophysiology of degenerative lumbosacral stenosis like?
- Type II disk degeneration or other degenerative changes at the LS junction causes collapse of the intervertebral disk space
- progresses to facet subluxation and facet joint hypertrophy
- transitional vertebrae (fused L7-S1) develops
What dogs commonly present with transitional vertebrae in DLSS? What is commonly involved?
German Shepherds - 8x more likely to develop DLSS 1-2 years earlier than normal
articular facets
What is the most common signalment associated with DLSS?
adult, large breed, males —> GSD overrepresented
What are 4 common historical features of the pelvic limb associated with DLSS?
- pain localized to back end
- unilateral or bilateral pelvic limb weakness
- scuffing of toes of the pelvic limbs
- muscle atrophy of the pelvic limbs due to sciatic nerve distribution
develops within weeks to months
What are 4 other historical features associated with DLSS?
- difficulty rising, especially after resting and at the stairs
- low tail carriage
- biting/chewing of hip region, tail, toes
- urinary and/or fecal incontinence
What are 3 findings on neurological exam in patients with DLSS?
- abnormal gait, lameness
- poor withdrawal reflexes often only at the hock
- delayed to absent proprioceptive positioning of the pelvic limbs
What are 4 common localizations of pain in patients with DLSS?
- at LS, with dorsal and/or ventral palpation
- lordosing LS
- dorsiflexing tail
- hip extension
Where can the L7 nerve root be palpated? How do dogs with DLSS respond?
medial to the ventral ilium
will be painful —> normal dogs will not mind
Where do L7 nerves come off?
off the transverse processes
DLSS = painful!
What is indicative of DLSS in the stance phase of the gait? What happends when these patients have their caudal thigh musculature manipulated?
pronation of supination
tense up
What 3 areas are commonly palpated to diagnose DLSS?
- BL 35 acupuncture point under the tail = painful
- tuber coxae and tuber sacrale with thumb and middle finger = L7 nerve root irritation
- groove between bicepfs femoris and semitendinosus = sciatic nerve irritation
What is the preferred diagnostic for DLSS?
MRI
- radiographs can rule out/in diskospondylitis
- CT
- contrast radiography
What 2 views are preferred for diagnosing DLSS on MRI? What can highlight L7/S1 compression?
- standard
- flexed/extended
oblique parasagittal planes
What medical management is recommended for DLSS? What additional treatments are also recommended?
- anti-inflammatories: Rimadyl
- analgesics: Tramadol, Gabapentin, Pregablin (Lyrica)
exercise restriction, physical therapy, electroacupuncture, laser therapy
What commonly develops with long-term medical management of DLSS?
permanent incontinence if not addressed surgically
What are 4 indications for surgical treatment for DLSS?
- refractory to medical therapy
- worsening pain
- worsening neurological deficits
- fecal and/or urinary incontinence
What is the standard method for correcting DLSS? What may also be required?
dorsal laminectomy
- facetectomy
- foraminotomy
- stabilization, diskectomy (controversial)
What is diskospondylitis? At what location is it most commonly found? What is the most common chief complaint?
infection of the disk space adjacent to the vertebral endplate
LS —> L7/S1
pain
What is the most common cause of diskospondylitis? What is seen in GSDs?
bacterial - Staphylococcus
fungal - Aspergillus
How is diskospondylitis diagnosed? What treatment is recommended?
- radiographs
- MRI more sensitive
long-term antibiotics —> good prognosis with bacterial infections
