The Lumbosacral syndrome

Question 1

What are the primary nerves from the L4-S3 spinal cord segments?

Answer 1

• Sciatic nerve
• Femoral nerve
• Pudendal nerve

Question 2

Where does the femoral nerve emerge from the spinal cord?

Answer 2

L4 and L5 (The F’s!)

Question 3

Where does the sciatic nerve emerge from the spinal cord?

Answer 3

L6 and L7 (The S’s!)

Question 4

Where does the pudendal nerve emerge from the spinal cord?

Answer 4

S1-S3 (PS)

Question 5

What is the primary reflex test used to test the femoral nerve?

Answer 5

Patellar reflex

Question 6

What is the primary reflex test used to test the sciatic nerve?

Answer 6

Withdrawal reflex; need to see flexion of all joints fully and with strength

Question 7

What is the primary reflex test used to test the pudendal nerve?

Answer 7

Perineal (anal) reflex

Question 8

What are the clinical signs associated with a lesion in the L4 to S3 spinal cord segment?

Answer 8

• Pain (screaming; reluctant to jump, stand-up or sit; palpation/rectal)
• Nerve root signature (crouched posture, low tail carriage)
• Urinary/fecal incontinence
• Motor deficits (LMN paresis/paralysis of pelvic limbs and/or tail)
• Sensory deficits

Question 9

What is a nerve root signature?

Answer 9

Pain associated with irritation or inflammation at a nerve root. Animals affected tend to hold their leg up when in pain

Question 10

What sort of sensory deficits can be seen in L4-S3 lesions?

Answer 10

• Proprioceptive deficits in pelvic limbs
• Reduced perianal reflex
• Hypoesthesia perineal area, pelvic limbs or the tail
• Reduced bulbocavernosus reflex

Question 11

What are common degenerative lesions seen in L4-S3?

Answer 11

• Disc protrusion or extrusion

- Degenerative lumbosacral stenosis

Question 12

What are common anomalous lesions seen in L4-S3?

Answer 12

• Congenital vertebral malformations

- Syringohydromyelia

Question 13

What is Syringohydromyelia and what breed is it predisposed?

Answer 13

-Presence of a cavity within the spinal cord parenchyma filled with cerebrospinal fluid

• CKCs have an abnormal conformation (shape) of the back of the skull (called the occipital bone) - Caudal part of the brain (cerebellum) doesn’t have enough space in the occipital bone and tends to pass through the foramen magnum (exit hole of the spinal cord)
• Creates a pressure point, giving rise to an abnormal flow of CSF from the brain to the spinal cord.
• With time this flow disturbance can result in the formation of a syrinx
• In some dogs, it can also cause a build up of fluid in the brain called hydrocephalus.

Question 14

What are common inflammatory/infectious lesions seen in L4-S3?

Answer 14

• Discospondylitis
• Granulomatous meningo-encephalomyelitis (GME)
• Neosporosis
• Distemper, FIP, Protozoal
• Bacterial myelitis (inflamm of spinal cord)
• Traumatic disk

Question 15

What dogs are commonly affected by lumbosacral stenosis?

Answer 15

Older large breed dogs

eg. GSD

Question 16

What is lumbosacral stenosis? (CS)

Answer 16

Stenosis of the vertebral canal and/or intervertebral foramina and/or the related vasculature

Bladder dysfunction, L4-S3 spinal cord segments

Question 17

What can cause lumbosacral stenosis/disesase?

Answer 17

• Hansen type II disc degeneration and protrusion at the lumbosacral junction (v. common)
• Subluxation of the articular facets
• Thickening and in-folding of the interarcuate ligament
• Epidural fibrosis
• Thickened lamina and pedicles
• Spondylosis, proliferative degenerative changes of the articular facets
• Instability and misalignment between the last lumbar vertebra and the sacrum

Question 18

What is pseudo-hyperreflexia?

Answer 18

If the sciatic nerve is not working, you get an increased patellar reflex because no counter tone, not because it’s actually increased

Question 19

What would you want to do to visualize a possible dynamic lumbosacral stenosis?

Answer 19

Dynamic myelographic study (radiographs)

Question 20

What is the conservative treatment for lumbosacral stenosis?

Answer 20

• Restricted exercise for 6-8 weeks
• Anti-inflammatories
• Pain relief

Question 21

What is the surgical treatment for lumbosacral stenosis?

Answer 21

Dorsal laminectomy; respond well but can get complications

A portion of the bone of a spinal vertebra is removed to allow access to the spinal canal and/or achieve decompression of the spinal cord

Rapid relief from pain in dogs

Question 22

What are some immediate post-surgical complications of lumbosacral surgery?

Answer 22

Seroma and hemorrhage, often due to too much movement after surgery

Question 23

What are some delayed post-surgical complications of lumbosacral surgery?

Answer 23

• Discospondylitis

- Lamina formation/fibrosis (secondary compression)

Question 24

What are the clinical signs of polyneuritis equi?

Answer 24

• Tail paralysis
• Dilated anus
• Fecal retention
• Perineal loss of sensation
• Muscle atrophy (some chronic cases)

Question 25

What are some differential diagnoses for polyneuritis equi?

Answer 25

- Trauma (sacral fracture common) - Equine herpes virus 1 myeloencephalopathy - infectious and fatal - Primary or secondary cystitis

Question 26

What is the pathogenesis of polyneuritis equi?

Answer 26

Immune-mediated damage to the peripheral nerves of the cauda equina; may affect other nerves, but mainly the cauda equine eg. Cranial nerves It may follow previous viral infection (possibly adenovirus) Occasionally seen in outbreaks

Question 27

How is a diagnosis of polyneuritis equi made ante mortem?

Answer 27

- Tail head muscle biopsy | - Lymphocytic infiltrate seen in or around the intramuscular nerves

Question 28

What is the treatment for polyneuritis equi?

Answer 28

- Usually supportive | - Immunosuppressive steroids not usually effective

Question 29

What is the prognosis for polyneuritis equi?

Answer 29

OK for life, but poor return to normal function. Requires long term owner support

Question 30

What is the cauda equina in horses?

Answer 30

- Bundle of spinal nerves and spinal nerve roots - L2 to L5 nerve pairs, S1 to S5 nerve pairs and the coccygeal nerve - Innervates pelvic organs + lower limbs to include motor innervation of the hips, knees, ankles, feet, internal anal sphincter and external anal sphincter - sensory innervation of the perineum and, partially, parasympathetic innervation of the bladder

Question 31

What does the lumbosacral region consist of in regards to anatomy?

Answer 31

L4-S3 spinal cord segments, cauda equina, nerve roots

Question 32

What are the two different plexuses that originate firstly from C6-T2 and L4-S3?

Answer 32

``` C6-T2 = Brachial Plexus L4-S3 = Lumbosacral Plexus ```

Question 33

What is the role of the UMN?

Answer 33

CNS: Brain ---> LMN Inhibitory (& Excitation) to LNM Inhibition most affected

Question 34

What is the role of LMN?

Answer 34

CNS ---> Periphery | Excitatory to muscles & glands

Question 35

What are the CS of UMN lesion?

Answer 35

Muscle tone • Normal to increased Reflexes • Normal to increased

Question 36

What are the CS of LMN lesion?

Answer 36

Muscle tone • Flaccid Reflexes • Reduced to absent

Question 37

What is a common nutritional lesion seen in L4-S3?

Answer 37

Hypervitaminosis

Question 38

What is discospondylitis?

Answer 38

Concurrent intervertebral disk infection and vertebral osteomyelitis of contiguous vertebrae (vertebral end plates + bodies) CS: spinal pain in large breed dogs Originates from: Blood stream or migrates to spine through adjacent diseased tissue

Question 39

What is spondylitis?

Answer 39

Degenerative, non-inflammatory condition of the spinal column RADS: productions of bone spurs along the bottom, sides, and upper aspects of the vertebrae of the spine CAUSE: Age, injury

Question 40

What are the common traumatic lesions to L4-S3?

Answer 40

Fractures | Luxations

Question 41

What are the common vascular lesions to L4-S3?

Answer 41

Ischaemic myelopathy | Haemorrhage