Small Animal Vertebral Column 2

sihirlifil's version from 2017-11-01 23:52

Metabolic, Inflammatory, Neoplasia

Question Answer
Hypervitaminosis A aka?Dietary osteodystrophy
This is a radiograph of a 9-year-old cat fed an exclusive raw liver diet. Dx?
Hypervitaminosis A
Hypervitaminosis A: what happens?Ossification of the entheses of axial skeleton (ligamentous structures)
Can lead to compression of nerve roots and spinal cord in severe cases (CNS SIGNS!)
Secondary nutritional hyperparathyroidism
Hyperparathyroidism: what happens?Generalized osteopenia, thin cortices of all vertebrae, severely malaligned vertebrae
List of metabolic disordersHypervitaminosis A (dietary osteodystrophy)
Hyperparathyroidism (1ry or 2ry)
Generalized osteopenia
(Osteopetrosis = )(Increased bone density due to abnormal turnover. Can't differentiate cortex from medulla)
Discospondylitis =Inflammation and sepsis of IVD & adjacent vertebral endplates
Involves 2 adjacent vertebral bodies!
Discospondylitis: radiographic signsAbnormal IVD space
Irregular/lytic endplates with increased opacity
Periosteal new bone formation
Shortened vertebrae
Vertebral fusion when healed (=block)
Spondylitis = Inflam of vertebrae
In dogs, localized ventral vertebral proliferation may be caused by?Spirocerca lupi
L2 & L3 affected. New bone formation ventrally on L2 & L3, both vertebral bodies show sclerosis
(Vertebral osteomyelitis/spondylopyosis = ?)(Septic (bacterial or mycotic) or suppurative inflammation/infxn of vertebra. Loss of clear margins, bone lysis or production, irregular periosteal reaction)
(Possible causes of vertebral osteomyelitis)(Hematogenous or 2ry infection caused by migrating FB, extension of adjacent soft tissue infection)
**Major difference between discospondylitis & spondylosisNo bone lysis in spondylosis
Proliferative changes are smoothly outlined
(Vertebral physitis = )(Lysis of caudal physeal region of affected vertebra, end plates remain intact, caudal part of vertebra may collapse. Spondylosis & malalignment may form)
Benign neoplastic lesions (3)Multiple cartilaginous exostoses
Malignant bone tumors (5)Osteosarcoma
Multiple myeloma
Multiple cartilaginous exostoses: look how?Expansive enlargements of dorsal laminae & spinous processes (may encroach on spinal cord if expands)
Osteochondroma =Only benign tumor of the vertebrae
Osteochondromatosis: CS?May cause compressive myelopathy
Primary malignant neoplasms affect how many vertebrae?Only 1
Benign lesions and secondary neoplastic lesions (metastases) may affect more than 1
Possible secondary malignant vertebral neoplasias (6)Anaplastic
Perianal gland
Transitional cell carcinoma
Neoplasia: radiological findingsLucency (bone destruction)
Loss of cortical outline
COllapse of IVD space
+/- proliferation of bone & paraspinal soft tissue masses
If you see 'punched-out' osteolytic lesions in vertebral bodies/laminae/dorsal spinous processes, think...Multiple myeloma or hemangiosarcoma
Multiple myeloma in lumbar spine of a cat
Multiple lucent, well-defined round/oval lytic lesions in vertebral bodies, arches, dorsal spinous processes
Bone appears spongy
Multiple myeloma in cervical spine of a dog
Multifocal lytic lesions, no sharp margins, no evidence of new bone formation (response to lytic lesions)
Lumbar spine neoplasia
Abnormal vertebral shape, outline, opacity (lookds more lucent)
Ventral new bone formation
Predisposed to pathological fracture
You see a lumbar spine neoplasia... next step?Radiograph the thorax for metastasis
How do aggressive lesions of the lumbar spine look?Don't form nice hooks, periosteal reaction (ventral on L6 & L7 in pic)
Which type of cancer likes to metastasize to the caudal lumbar vertebrae?Prostatic adenocarcinoma
How can you tell if metastasis to the prostate has occurred? What else might be involved?Mineralization within the prostate, ill-defined contour
Spread to sublumbar LN is common (enlarged on US) (Enlarged, heterogenous medial iliac LN in pic)
Meningioma in cat
(Enlarged IV foramen, vertebral canal)
(Example of extradural neoplasia? Causes what?)(Nerve sheath tumor: enlargement of IV foramina (bone atrophy caused by chronic pressure by expansive tumor))

Trauma, IVD Disease

Question Answer
Most common sites for fracturesVertebral body
Transverse processes
Spinous processes
How can subluxation & luxation occur?With or without associated fracture
T/F IVD disease is an inherited conditionsFALSE! Degenerative
Breeds predisposed to IVD dz? Genders?Chondrodystrophic breeds (Daschund>Beagles)
No gender predilection
Common sites of IVD diseaseThoracolumbar (T12-23, T13-L1)
Cervical (C2-3, C3-4)
Cats who get IVD disease tend to be?Older, and rarely show CS
There are no IVD spaces betweenC1 & C2, and between the fused sacral vertebrae
The IV space consists of (4)Annulus fibrosus
Dorsal longitudinal vertebral ligaments
Ventral longitudinal vertebral ligaments
Nucleus pulposus (jelly-like)
Vertebral symphysis formed byDorsal & ventral longitudinal ligaments of the IV space (symphyseal joints)
How is the epidural space in the dog?SMALL! (accentuated in Dachshund compared to GSD: more severe neuro signs in Dach following protrusion)
In the cervical spine, the dorsal longitudinal ligament is thicker, which means...?Higher incidence of lateral disc protrusion with compression of nerve roots in the neck
More severe CS occur with TL disc protrusion compared to cervical spine... why?Epidural space is relatively wider in cervical spine
Protrusion =Non-specific term describing any mass of discal origin impinging on spinal cord or nerve roots
Herniation =Nucleus pulposus causes a bulge, stretching the intact annulus fibrosis
Extrusion/prolapse =Nucleus has broken through the annulus into epidural space
Chondroid degeneration =Dehydration & mineralization of nucleus pulposus
Annulus fibrosus degenerates, can no longer contain the abnormal nucleus
Type 1 IVDD: characteristicsAcute onset as a result of chondroid degeneration & calcification (dynamic forces of vertebral column cause protrusion)
Chondodystrophoid dogs
Type 2 IVDD: characteristicsSlower onset caused by fibroid degeneration (AF stretches or partially ruptures, or hypertrophy and protrude into vertebral canal, cord compression)
Older dogs, can also happen in non-chondrodystrophoid breeds
Which Hansen type causes more severe neuro signs?Type 1 tend to be forceful, acute lesions causing compressive myelopathy & severe neuro signs (+/- epidural hge & spinal cord edema)
Arrowhead = ? Star = ?
Arrowhead = Annulus fibrosus
Star = Nucleus pulposus
How does the intercapital ligament run?Between rib heads, dorsally across IV disc
What does the intercapital ligament do?Additional support to the dorsal annulus in the thoracic vertebral column = less disc prolapse in thoracic spine
Hansen Type I lesion
Chondroid degeneration (dehydration & mineralization of NP, AP degenerates)
Compressive myelopathy & severe CNS signs, epidural hge, cord edema
How does disc degeneration sometimes manifest?
(Mineralized discs at C2-3 & C3-4)
(Prolapsed at C2-C3)
WHat is fibroid degeneration?Fibroid metaplasia of the nucleus pulposus
Old, non-chondrodystrophic dogs
Often associated with hypertrophy of the dorsal longitudinal ligament
What is the 'domino effect'?Degenerative lesions often also present in adjacent joints
Whats going on here? How can you tell?
IVD herniation
Narrowed IVD space at T13-L1
Radiographic signs of IVD herniation?Narrowed IV foramen (Woodstock shape)
Narrowed dorsal interarticular joint space
Something to be careful of when looking at the IVD joint space?Joints are normally wider in the back when flexed... but ALL will be, not just 1!
What's the arrow pointing to?
Abnormal ossification superimposed with IV foramen (+/- IVD space)
Associated with narrowed IV space is compatible with extruded mineralized IV disc material

Technique (extra ppt)

Question Answer
For lumbosacral spine, consider doing what beforehand?Enema!
How do intervertebral spaces appear in the periphery of the x-ray beam?Oblique
It takes ___ # projections each in lateral and VD projection to image the entire spine in a large dog4-5
List the projections for the spineOccipito-atlanto-axial
Cervical, cervicothoracic
Special view: oblique projection. What is it?V45*LDRO; V45*RDLO
Allows to define lateralization of spinal lesions
Stress view: hyperextended for?Occiptio-atlanto-axial
Stress view: hyperflexed for?Caudal cervical
What special views can we take?Oblique (V45*LDRO; V45*RDLO)
Stressed (hyperflexed, hyperextended)
Traction views of cervical region
Open mouth projections for the dens axis/odontoid peg
What must you do for a VD view of the occipito-atlanto-axial region?
Remove ET tube (and be super fast!)
Steps for taking a Lat view of the cervical spine
Support middle of neck with foam pad or sponge (large dogs also mid-neck)
Center x-ray beam on center of neck (palpate the vertebrae)
Hyperextended, hyperflexed & traction views may be added
ET tube may stay in place
Forelimbs pulled caudally
Steps for taking a VD view of the cervical spinePatient in dorsal recumbency
Head and neck straight
Forelimbs pulled caudally
Center and collimate including occiput to T1
Remove ET tube just prior to exposure to avoid superimposition
What’s wrong with this image?
Position not straight!
Steps for taking a Lat & VD view of the cervicothoracic spineSupport neck and thorax
Limbs extended in neutral position
Increase kV by 10 (increased tissue thickness at this level compared to cervical spine)
Center and collimate to include C6 to T12 (palpate the vertebrae)
VD view: remove ET tube
Steps for taking a Lat view of the thoracic spinekV increased by 10 from cervical (same as cervicothoracic)
Grid in med/large dogs
Extend forelimbs cranially
Avoid rotation: support sternum
Include dorsal spinous processes
Center Just cranial to xyphoid
Markers obv
What’s the blue arrow pointing at?
Rotation! wasn’t positioned properly
How is the VD view of the cervical spine?Often unsatisfying in large dogs (vertebral column poorly visible, thoracic structures superimpose)
How do you position the patient straight for a VD thoracic spine?Dorsal spinous processes superimposed centrally on thoracic vertebrae
Technique for thoracolumbar regionInclude view centered on IVD! Common location for disc disease
Avoid rotation
~Center on thoracolumbar junction
VD may be unsatisfying: overlying ST structures of abdomen
Technique for lumbar regionLat, VD, & oblique views
Ensure straight positioning
Lat: extend HL caudally
VD: superimposition of colon & prepuce/os penis in male dogs~
What are the blue arrows pointing to? Orange?
Blue = Prepuce
Orange = os penis
Technique for lumbosacral region
Lat, VD, extended/flexed lateral
Which normal variation is this?
Anticlinal vertebra
Which normal variation is this?
Ventral contour of L3-L4 less defined due to attachment of diaphragmatic crura

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