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Small Animal Neuroradiology: The Spine Lecture 2 – Degenerative Diseases, Diseases causing Instability, Vertebral Injury, Infection and Neoplasia VCA.

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Presentation on theme: "Small Animal Neuroradiology: The Spine Lecture 2 – Degenerative Diseases, Diseases causing Instability, Vertebral Injury, Infection and Neoplasia VCA."— Presentation transcript:

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 VCA 341 – The Spine Matthews

4 Intervertebral Disc Disease
Anatomy Thrall Veterinary Diagnostic Radiology 5th Ed Insert picture VCA 341 – The Spine Matthews

5 Intervertebral Disc Disease
Protrusion Herniation Extrusion Insert picture VCA 341 – The Spine Matthews

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 VCA 341 – The Spine 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 VCA 341 – The Spine Matthews

11 Intervertebral Disc Disease
Narrow IVD space Narrow IV foramen Narrow articular facet joint TUSCVM VCA 341 – The Spine Matthews

12 Intervertebral Disc Disease
Mineralized material in plane of vertebral canal over IVD space TUSCVM VCA 341 – The Spine Matthews

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) VCA 341 – The Spine Matthews

14 Intervertebral Disc Disease
Need loss of visibility of the contrast column to say lesion is compressive VCA 341 – The Spine Matthews

15 Intervertebral Disc Disease
CT MRI VCA 341 – The Spine Matthews

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 VCA 341 – The Spine 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 VCA 341 – The Spine Matthews

20 Atlantoaxial Instability
Normal Groves187683 Agenesis of the dens VCA 341 – The Spine Matthews

21 Atlantoaxial Instability
Fracture of dens Petty TUSCVM VCA 341 – The Spine Matthews

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 VCA 341 – The Spine Matthews

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 Matthews

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 Matthews

31 Lumbosacral Instability
Articular facet osteoarthrosis Spondylosis TUSCVM VCA 341 – The Spine Matthews

32 Lumbosacral Instability
Subluxation of sacrum Wedged IVD space Sclerosis and irregularity of endplates TUSCVM VCA 341 – The Spine Matthews

33 Lumbosacral Instability
Contrast techniques Myelography Epidurography Discography VCA 341 – The Spine Matthews

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 VCA 341 – The Spine 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 Matthews

36 Vertebral Injury Vertebral canal malalignment due to subluxation of vertebral bodies TUSCVM VCA 341 – The Spine Matthews

37 Vertebral Injury Compression fracture VCA 341 – The Spine Matthews
TUSCVM VCA 341 – The Spine Matthews

38 Vertebral Injury Complete luxation TUSCVM VCA 341 – The Spine Matthews

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 Matthews

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 VCA 341 – The Spine Matthews

42 Discospondylitis with vertebral subluxation
VCA 341 – The Spine Matthews

43 Discospondylitis Alternative imaging Myelography CT MRI
Nuclear scintigraphy VCA 341 – The Spine Matthews

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 VCA 341 – The Spine Matthews

47 Spondylitis Vertebral physitis – reaction adjacent to endplate
Endplate spared Physitis TUSCVM VCA 341 – The Spine Matthews

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). VCA 341 – The Spine Matthews

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) VCA 341 – The Spine Matthews

50 Neoplasia Osteosarcoma – primarily osteoproductive lesion
TUSCVM VCA 341 – The Spine Matthews

51 Neoplasia Multiple myeloma – “punched out” lesion through axial skeleton TUSCVM VCA 341 – The Spine Matthews

52 Neoplasia Histiocytic sarcoma – osteolytic lesion VCA 341 – The Spine
TUSCVM VCA 341 – The Spine Matthews

53 Neoplasia Metastatic prostatic carcinoma VCA 341 – The Spine Matthews
TUSCVM VCA 341 – The Spine Matthews

54 The End VCA 341 – The Spine Matthews


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