1. Small Animal Neuroradiology: The Spine Lecture 2 – Degenerative Diseases, Diseases causing Instability, Vertebral Injury, Infection and Neoplasia
VCA 341 Fall 2011
Andrea Matthews, DVM, Dip ACVR
Assistant Professor of Radiology

2. Spondylosis Deformans
Bone on ventral aspect of the vertebral bodies arising from the endplates Sometimes bridges the entire intervertebral disc space
VCA 341 – The Spine
Matthews

3. Spondylosis Deformans
Courtesy Dr. L. Pack
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4. Intervertebral Disc Disease
Anatomy
Thrall Veterinary Diagnostic Radiology 5th Ed
Insert picture
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5. Intervertebral Disc Disease
Protrusion
Herniation
Extrusion
Insert picture
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6. Intervertebral Disc Disease
Chondroid degeneration
Chondrodystrophic breeds
Dehydration and mineralization of the nucleus
Hansen Type I lesions
Extrusion of disc material into vertebral canal
Acute – neurologic signs due to spinal cord compression
Most commonly between T12-L2 and C2-3 in cervical region
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Matthews

7. Intervertebral Disc Disease
Fibroid degeneration
Non-chondrodystrophic breeds
Fibrous metaplasia of the nucleus
Hansen Type II lesions
Stretching, partial rupture or hypertrophy of annulus with bulging into vertebral canal
Chronic progressive course
Can cause neurologic signs, typically chronic and progressive in nature and milder than the acute extrusion
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

8. Intervertebral Disc Disease
High velocity, low volume disc extrusion
Young to middle aged dogs
No degeneration of nucleus
Gelatinous nucleus extrudes into vertebral canal
Usually secondary to trauma
Causes concussive spinal cord injury
Sometimes referred to as Type III disc extrusion
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

9. Intervertebral Disc Disease
Clinical features
Dachshunds are over-represented
Less common in cats
Neurologic signs are related to the site of extrusion
UMN versus LMN
C1-5, C6-T2, T3-L3, L4-S3
Intercapital ligaments from T2-T10 joining rib heads usually prevent extrusion in thoracic spine
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

10. Intervertebral Disc Disease
Survey radiographs
Mineralized material in plane of intervertebral disc space
Indicative of degeneration, not necessarily extrusion
May see mineralized material in plane of vertebral canal in case of disc extrusion
Important to use 2 views
Narrowing of intervertebral disc space
May be wedged in appearance
Narrowing of the articular facet joint space
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
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11. Intervertebral Disc Disease
Narrow IVD space
Narrow IV foramen
Narrow articular facet joint
TUSCVM
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12. Intervertebral Disc Disease
Mineralized material in plane of vertebral canal over IVD space
TUSCVM
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13. Intervertebral Disc Disease
Myelography
97% accurate in identifying site and lateralizing disc hernia CT
Good for mineralized disc material; need myleogram if disc material not mineralized
MRI
Good for all types of spinal cord compression
(Kirberger, Vet Rad)
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14. Intervertebral Disc Disease
Need loss of visibility of the contrast column to say lesion is compressive
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15. Intervertebral Disc DiseaseCT
MRI
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16. Atlantoaxial Instability
Space between the dorsal arch of C1 and the spinous process of C2 C1 C2
Dens (odontoid process)
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
Wings of C1 (atlas)
TUSCVM
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Matthews

17. Atlantoaxial Instability
Ligaments of the A-A joint
Dorsal atlanto axial ligament
Alar ligaments (2)
Apical ligament
Transverse ligament C2
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord C1
VCA 341 – The Spine
Matthews

18. Atlantoaxial Instability
Radiographic findings
Increased distance between dorsal spinous process of C2 and dorsal arch of C1
Dorsal deviation of C2 causing step in vertebral canal
Absent or small odontoid process
Fractured odontoid process
Views
Lateral, ventrodorsal, lateral oblique
Flexed lateral must be performed after survey
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

19. Atlantoaxial Instability
Groves187683
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20. Atlantoaxial Instability
Normal
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Agenesis of the dens
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21. Atlantoaxial Instability
Fracture of dens
Petty
TUSCVM
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22. Cervical Vertebral Instability
Large breed dogs
Young Great Danes (<1year)
Older Dobermans (3-9 years)
St. Bernards, Mastiffs, Basset Hounds…
Males affected more commonly than females
Caudal cervical spine most common (C5-7)
Also C2-4 but less frequently
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

23. Cervical Vertebral Instability
Abnormalities
Congenital malformation and malarticulation of vertebral bodies, articular facets, vertebral arches and pedicles
Dorsal vertebral tipping and subluxation
Degenerative joint disease of articular facets
Ligamentum flavum hypertrophy
Hypertrophy of the dorsal annulus fibrosus and stretching/hypertrophy of the dorsal longitudinal ligament
Intervertebral disc disease (Hansen type II)
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

24. Cervical Vertebral Instability
Static lesion
Does not change with different positions of the neck (neutral, flexion, extension or traction)
Usually due to IVD herniation or bony abnormalities (malformation, facets proliferation)
Dynamic lesion
Changes according to the position of the neck
Due to ligamentous hypertrophy
Traction or flexion of the neck will the severity of the lesion; Extension will exacerbate the lesion
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

25. Cervical Vertebral Instability
Articular facet degenerative joint disease
Flint
TUSCVM
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26. Cervical Vertebral Instability
Example of Dynamic lesion
Funnel shaped appearance of cranial aspect of vertebral body with dorsal tipping of cranial aspect of vertebral body
Flint
Narrowing of vertebral canal with spinal cord compression
VCA 341 – The Spine
Matthews
Courtesy L. Pack

27. Cervical Vertebral Instability
Example of Dynamic and Static Lesion
Flexed view – compression of spinal cord with tipping of vertebral body and mineralized material
TUSCVM
Traction view – the spinal cord remains compressed
VCA 341 – The Spine
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28. Lumbosacral Instability
Also known as…
Cauda equina syndrome
Lumbosacral stenosis…
Congenital or acquired abnormalities causing biomechanical changes
Cause compression of nerve roots
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

29. Lumbosacral Instability
Cauda equina
Nerves exiting the terminal spinal cord
Spinal cord termination- L4 in large breeds and cranial aspect ofL6 in small breeds
Clinical features
Seen in cats and dogs
German shepherds are predisposed
Higher incidence seen in animals with a transitional vertebra
Annulus may stretch, partially rupture or hypertrophy and bulge into the vertebral canal, compressing the cord
VCA 341 – The Spine
Matthews

30. Lumbosacral Instability
Etiologies
Disc herniation at L6-7 or L7- S1
Spondylosis deformans and facet osteoarthrosis (DJD)
Congenital lumbosacral canal stenosis
Radiographic findings
Static or dynamic condition
Narrow and wedged intervertebral disc space
Narrow vertebral canal
Ventral and lateral spondylosis deformans
Articular facet osteoarthrosis
VCA 341 – The Spine
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31. Lumbosacral Instability
Articular facet osteoarthrosis
Spondylosis
TUSCVM
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32. Lumbosacral Instability
Subluxation of sacrum
Wedged IVD space
Sclerosis and irregularity of endplates
TUSCVM
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33. Lumbosacral Instability
Contrast techniques
Myelography
Epidurography
Discography
VCA 341 – The Spine
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34. Vertebral Injury Fractures Important points Fracture of vertebra
Care in handling the patient
Perform lateral view firs to rule out major fractures before proceeding
Fracture of vertebra
Body, lamina, pedicles
Transverse or spinous processes
Endplates (young animals)
Compression fracture
Subluxation/ luxation
Pathologic fracture
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Matthews

35. Vertebral Injury
Vertebral endplate fracture with subluxation of endplate and widening of the articular facet joint. Note the vertebral canal malalignment
VCA 341 – The Spine
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36. Vertebral Injury
Vertebral canal malalignment due to subluxation of vertebral bodies
TUSCVM
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37. Vertebral Injury Compression fracture VCA 341 – The Spine Matthews
TUSCVM
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38. Vertebral Injury
Complete luxation
TUSCVM
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39. Discospondylitis
Infection involving the intervertebral disc and adjacent endplates
Mostly through hematogenous route
Sources – bladder, heart, teeth and skin
Staphylococcus spp, Escherichia coli, Brucella canis most common
Also Streptococcus spp., Pasteurella multocida, yeast-like organisms, etc
Fungal organisms also reported
Seen in young adult, male, large breed dogs
VCA 341 – The Spine
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40. Discospondylitis Radiographic findings Can affect any disc space
L7-S1, caudal cervical and mid-thoracic spine most common
Radiograph entire spine if find one lesion as there can be multiple
Can take 3-4 weeks after onset of clinical signs for radiographic changes to become visible
Similarly, resolution of radiographic changes lags behind clinical improvement
VCA 341 – The Spine
Matthews

41. Discospondylitis Collapsed IVD space
Endplate lysis with adjacent sclerosis
Irregularity of endplates
Spondylosis
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42. Discospondylitis with vertebral subluxation
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43. Discospondylitis Alternative imaging Myelography CT MRI
Nuclear scintigraphy
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44. Spondylitis Infection of a vertebral body = osteomyelitis of spine
Hematogenous spread of infection from elsewhere
Extension from infection of surrounding soft tissues
Migrating grass awn
Iatrogenic
Post spinal surgery
Vertebral physitis
In younger animals, adjacent to the endplate
VCA 341 – The Spine
Matthews

45. Spondylitis Radiographic findings DDX – metastatic carcinoma
Poorly marginated osteolysis
Ill-defined periosteal reaction on ventral vertebral body
Sometimes extends to lateral aspect of vertebra
Extends to mid vertebral body, unlike spondylosis deformans
Variable sclerosis of vertebral bodies
Often multiple vertebral bodies affected
DDX – metastatic carcinoma
VCA 341 – The Spine
Matthews

46. Spondylitis Migrating grass awn – causing fuzzy, periosteal reaction
Ledford
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47. Spondylitis Vertebral physitis – reaction adjacent to endplate
Endplate spared
Physitis
TUSCVM
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48. Neoplasia Benign tumors Relatively rare Osteoma Chondroma
Multiple cartilaginous extostoses - MCE (osteochondromatosis)
MCE
Cross, J. & Tromblee, T. What is your diagnosis? J Am Vet Med Assoc (2007).
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49. Neoplasia Malignant tumors Metastatic neoplasia Primary bone tumors
Osteosarcoma, Chondrosarcoma, Fibrosarcoma
Multiple myeloma…
Metastatic neoplasia
Axial skeleton (ribs, vertebra) most common site of metastasis
Carcinomas (prostatic, bladder, mammary, perianal)
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50. Neoplasia Osteosarcoma – primarily osteoproductive lesion
TUSCVM
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51. Neoplasia
Multiple myeloma – “punched out” lesion through axial skeleton
TUSCVM
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52. Neoplasia Histiocytic sarcoma – osteolytic lesion VCA 341 – The Spine
TUSCVM
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53. Neoplasia Metastatic prostatic carcinoma VCA 341 – The Spine Matthews
TUSCVM
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54. The End
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