Diseases of the cervical spine

Question 1

What anatomy is involved?

Answer 1

7 cervical vertebrae
C1 - atlas
C2 - axis

C6 and C7 is where most degenerative disease is located

Question 2

How many articulations are there on each vertebrae?

Answer 2

3
- left and right articular process joints (facet joint)
- intervertebral joints

Question 3

What structures are highlighted by the circle and arrows?

Answer 3

Circle - intervertebral foramen
Arrows - spinal cord

Question 4

What are the 3 main manifestations of cervical disease?

Answer 4

• Neck pain/dysfunction
• Forelimb lameness
• Ataxia – cervical stenotic myelopathy

Question 5

What clinical signs are suggestive of neck pain?

Answer 5

• Reduced range of motion during baited stretches
• Changes in position or posture
• Palpation findings – enlarged joints
• Reduction in muscle mass

Question 6

How can neck pain cause forelimb lameness?

Answer 6

Classicaly an outside limb lameness - ‘hopping’ type

Two main mechanisms at play here:

A consequence of muscle dysfunction
* Many cervical muscles are involved in protraction of the forelimb
* Brachiocephalicus – changes in strength or function can cause asymmetry

Radiculopathy – neuropathic pain
* Compression of a spinal nerve root in the caudal cervical region (feeding brachial plexus)
* Enlarged APJs are the culprit

Question 7

What are the arrows pointing to?

Answer 7

Progressive radiculopathy
1 - normal
2 - moderate
3 - severe
Occlusion of the intervertebral foramen and impingement of the spinal nerve root

Question 8

What advanced imaging can we use to investigate diseases of the cervical spine?

Answer 8

CT is the only 3D imaging modality that can accommodate the equine neck!

Requirements:
* Large bore CT scanner
* General anaesthesia
* Often combined with myelography (injecting radiocontrast into the CSF)

VASTLY improves diagnostic accuracy, but we have to take care not to over-interpret findings!

Question 9

What does the CT myelography image show?

Answer 9

• New bone forming on lateral aspect of right articular process
• Lipping and osteophytes on both sides of the articular process joints
• New bone formation in the sclerosis of both sides of the articular process joints
• Spinal cord involvement

Question 10

How would you manage diseases of the cervical spine?

Answer 10

Intra-articular medication with corticosteroids is the mainstay
* Cannot reverse bone remodeling but can alleviate pain and reduce associated soft tissue inflammation
* There are no landmarks on the surface, and the target is deep beneath muscle…
* Injections are performed under ultrasound guidance.

Question 11

What is the prognosis with diseases of the cervical spine?

Answer 11

• Prognosis is variable and often unpredictable…
• Perhaps because advance imaging isn’t available for all cases!
• Horses with neck pain will do better than horses with radiculopathies who will do better than horses with spinal ataxia