SPINE - malformation Flashcards
Which feline breed is overrepresented in thoracic vertebral canal stenosis?
+ mutation
British Shorthair -> narrower vertebral canal in this breed
mut LTBP3
Male neutered, median age 9 years
Chronic, progressive, painful, T3–L3 myelopathy
Which IVDS is(are) most commonly affected in juvenile CSM?
C5-C6 & C6-C7
Mostly by osseous-associated spinal cord compression and multiple compressive sites. Almost half of the dogs had intervertebral disk degeneration. Intervertebral disk protrusion was seen in both giant and large breed dogs.
German shepherd dog has most commonly a disc-associated CSM: true or false?
False
The 10 GSDs of the present retrospective case series had CSM that was often characterized by osseous changes and a ligamentous component and were older than dogs of other breeds (eg, Great Dane and Mastiff) with osseous-associated CSM described in previous reports.
There is a male predisposition for spinal arachnoid diverticula: true or false?
True
Which criteria can be used to pick breeding French Bulldog in order to reduce number of hemivertebrae?
Shorter tail associated with increase of number and grade of hemivertebrae.
What are the associations between syringomyelia, caudal sac termination, pain, and spinal cord termination in CKCS?
TL SM -> more caudal dural sac termination
Lumbar SM -> more caudal SC termination
Painful without SM -> decreased distance between dural sac and SC termination = shorter filum terminale internum length
More observed hemivertebrae and ventrolateral hypoplasia hemivertebra subtype were associated with higher likelihood of neurological disease: true or false?
False
Fewer hemivertebrae
Ventrolateral hypoplasia
Pugs
Severe kyphosis
Which neural tube defect is associated with the following definition?
Failure of the vertebral arch(es) to close over the spinal cord
Spina bifida
May be associated with MC or MMC
The terms occulta (no neural tissue involved), cystica/ manifesta/aperta (associated MC or MMC through vertebral defect) are used depending on the amount of neural and associated tissue involvement
Which neural tube defect is associated with the following definition?Protrusion of meninges through open vertebral arch or cranial bones
Meningocele
def spinal cord dysraphism
Failure of the neural folds to appose and close, resulting in failed neural tube closure
def Myeloschisis
Failure of neural tube closure resulting in persistent attachment of the cutaneous ectoderm to the neural plate and inability of the vertebral arches to close around the open neural plate
Always results in spina bifida
dif with meningomyelocoele: cystic component in MMC
def meningomyelocele
Protrusion of meninges and nervous tissue through open vertebral arch
Which neural tube defect is associated with the following definition?
Failed separation of the neural tube from the skin ectoderm causing tubular sacs lined with hair follicles, sweat, and sebaceous glands that typically extends from the dorsal midline to underlying tissues
predisposed breed and mut
Dermal sinus tract
Duplication of FGF3, FGF4, FGF19, and ORAOV1 gene mutations responsible for the dorsal hair ridge in Rhodesian and Thai Ridgeback dogs predisposes these breeds
Which neural tube defect is associated with the following definition?
Any malformation of the spinal cord owing to abnormal interaction of the notochord, paraxial mesoderm, and neural plate during neurulation
breed and mutation
Myelodysplasia
Note: “Weimaraner spinal dysraphism” owing to a frameshift mutation in the NKX2-8 gene is considered a misnomer and is more accurately described as myelodysplasia
Which ligament provides the greatest stabilizing force of the canine atlanto-axial joint?
Alar
other ligt: apical, transverse
Which vertebral abnormality is associated with lumbosacral stenosis in cats?
Is this factor associated with development of clinical signs?
Lumbosacral transitional vertebrae (54%)
No
Clinical signs associated with lumbosacral stenosis included lumbosacral pain, low tail carriage, difficulty jumping, and urinary or faecal incontinence.
Neurological signs included proprioceptive deficits, ambulatory paraparesis, pelvic limb ataxia, reduced spinal reflexes and reduced perianal reflex.
Vertebral malformations: choose the INCORRECT
- Among neurologically normal French Bulldogs, approximately 80% have radiographic evidence of hemivertebra with or without kyphosis
- Pugs have much less prevalence of hemivertebra than French Bulldogs (around 17%) but do have other more frequent malformations like only 12 thoracic vertebra or transitional vertebra.
- Pugs, even though they have less prevalence for hemivertebra than French Bulldogs, appear much more prone to be presented with clinically relevant hemivertebra than Bulldogs.
- None of the above
4.
In cranial thoracic myelopathies (T1-T6) in cats, the cutaneous trunci reflex is usually…
Normal (86%)
Transitional vertebrae represented the most common abnormalities in the thoracolumbar and lumbosacral segments: true or false?
True
Cite 3 hallmarks for radiologic diagnosis of atlanto-axial instability.
Dorsal displacement of the axis into the vertebral canal
Increased distance between the arch of the atlas and the spinous process of the axis
Hypoplasia, aplasia or dorsal angulation of the dens
At what age the ossification of proatlas occurs? Fusion ossification center C1?
42 days
3-4 months
AA instability: choose the incorrect
1.Dorsal and ventral surgical procedures have comparable success rates that are around 85%
2.Dorsal procedures have a higher incidence of postoperative neurological deficits
3.Acute onset of signs and younger age at onset are positive predictive factors for neurological success.
4.Postoperative atlantoaxial reduction and radiographic appearance of the dens was a positive predictive factor for neurological success
4.
What are the most common sites of SAD?
C2-C3, C5, C6 (large breeds, in particular Rottweiler)
T9-T13 (small breeds, in particular Pug)
cite neural tube defects
anencephaly, encephalocele, craniorachischisis, iniencephaly, and spina bifida
Caudal Thethered spinal aracnhoid diverticula is associated with
1. better short term outcome
2. caudal syringomyelia
3. longer SM
- true
- false cranial
- true
atypical head tilt neurolocalisation and mechanism
paradoxical:
cerebellum (floculonod lobe, caudal cereb peduncle): loss of cerebellar inhib to ipsilat vestib nuclei
forebrain (ventrolat and paramedian thalamus): damage to adjacent midbrain
non paradoxical:
spinal nerve, dorsal root or dorsal GM (spinocerebellar and vestibulospinal) of C1-C3: loss of general propriocept afferent from neuromusc spindles
lesion caudal to C3 superficial dorsal horn controlat: pain
mutation associated with pituitary dwarfism and associated vert malformation
LHX3
Sheperd dog (German Sheperd, Saarlos)
atlanto-axial malformation
most common T1-T6 myelopathies in dog
neoplasia > anomalies > degen
neoplasia assoc with spinal hyperesthesia
name of the band that atatched ventral surf of dura matter of the SC to dorsal surf of vert bodies
meningovertebral ligt (caused bilobed shape)
cobb angle asociated with neurological signs
34.5°
features of constrictive myelopathy in pug
subarachnoid space has a focal, irregular and stellate shape
abnormal T2 hypoint bands within subarachn space (T1 hypo)
circumpherencial/focalcontrast enhanct of meninges
V shapeextradural ventral lesion
focal intramed T2 hyper
mutation associated with primary congenital hypotyroidism in cat
TPO (tyroid peroxydase)
disproportionate dwarfism
epiphyseal dysplasia, delayed physeal closure
best cutoff value for diagnosis of atlanto-axial intability in CT/MRI
+flexion angle for XRay
ventral compression index = ratio between ventral and dorsal atlantodental interval
cutoff 0.16 in extended 0.2 in flexed
51° flexion to cerv radiograph (atlas/axis angle>10°)
atlanto-oxipital band: ligt, more prononced in extension/flex
associated with … in CKCS
dorsal interacuate
more prononced in extension (cerebellar herniation more prononced in flexed)
associated with presence (not severity) of clinical signs and presence and severity of SM
dermoid sinus classification + predisposition
I. connect to supraspinous ligt
II. fibrous band connecting to supraspinous ligt
III. terminate superficially to supraspinous ligt without attaching to it
IV: attached to dura
V: true closed epidermal cyst
VI: tubular sac that extend from epidermitis and attached dura
predisposition of Rhodesian Ridgeback assoc with dupplication of fibroblast growth fact gene (FGF3, FGF4)
Cat and dog breed predisposed to spina bifida
Cat: Manx
Dog: English Bulldog, german sheperd
% stability confered by articular process
30%
The articular processes in the cranial thoracic spine (T1-T9) also function in weight-bearing.
orientation of articular process
cranial C3-C7: craniodorsal
caudal C3-C7: caudoventral
cranial T1-T9: dorsal
caudal T1-T9: ventral
cranial T10: dorsal
caudal: lateral
cranial T11-T13: medial
caudal T10-T13: lateral
cranial lumbar: dorsal-medial
caudal lumbar: dorso-lateral
In locations of the vertebral column where stability is imperative, mobility of the adjacent vertebral bodies is limited by opposing incline of articulating caudal and cranial processes.
verebra with largest (height) diameter of the cord
within atlas
breed differences in the overall size of the canine skeleton/vert canal, but circumference of the cord does not vary
in which vertebra are accessory process present?
from the midthoracic spine and may continue as far caudal as L5 or L6
restrict lateral bending
Accessory processes arise from the caudal lateral border of the pedicle and are oriented in a caudal and dorsal direction. cranial base of the cranial articular process of the adjoining vertebra will fit into the lateral ventral notch created by the space between the pedicle and the accessory process
breed + localisation + tratement of enlargement of the articular processes
Scottish deerhound
C2-C3
injection of triamcinolone acetonide (steroid) and lidocaine hydrochloride into the affected articular process joint under fluoroscopic guidance
articular dysplasia potential causes (3)
- mutation of the Hox gene
- dysgenesis of neural arch centers
- failure of accessory ossification center to develop or unite with the lamina
2 types of extradural synovial cyst + potential origin
- Synovial: synovial lining containing fluid
- Ganglion: contain myxoid material with no specific lining
Possible origins:
osteoarthritic changes and increased motion at the joint causes protrusion of the synovial membrane through defects of the joint capsule
proliferation of pluripotent mesenchymal cells, myxoid degeneration with cyst formation in collagen tissue, and increased production of hyaluronic acid by fibroblasts
Spinal instability or excessive mobility has been suggested as a cause, which is supported in that the 2 most common locations for synovial cyst formation are the lumbosacral region and the caudal cervical region
Large breed, middle-aged, or older dogs (median age 8 years).
% of synovial cyst in dogs affectected with cervical spondylomyelopathy
20%
MRI is reported to have a sensitivity of 90% for the diagnosis of extradural synovial cysts, compared with 70% with CT
def Tarlov cyst
extradural cysts involving the spinal nerves
out-pouching of the perineurium surrounding the spinal nerve
in human type 2 meningeal cyst
rate of concurrent disease in subarachnoid diverticula + breeds with higher rate
21%
Pug dogs (33.3%) and French bulldogs (61.5%) had high rates of concurrent disease
intervertebral disc extrusion or protrusion, concurrent vertebral
malformation, or previous surgery for intervertebral disc extrusion
maj localisation of subarachnoid divert
55% cervical
45% thoracolumbar
maj C2 and C3, C5, and C6, and T9 to T13
Rottweilers cervical
young, heavier dogs with large heads may be predisposed to cervical SAD
male or female are overrepresent in SAD
male
Progesterone receptors have been identified in the lining of intracranial arachnoid cysts in humans. CSF volume has been shown to be influenced by hormonal fluctuations
% of dorsal and ventral SAD
80% - 90% dorsal
6 - 8% ventral
% spinal hyperestesia/incontinence in SAD
20%
8%
breeds predisposed to SAD
Rottweilers, pugs, and French bulldogs
Pugs were significantly older
Dogue de Bordeaux had a lower age at onset
def dermoid and epidermoid cyst
congenital inclusion cysts that arise from cutaneous ectodermal tissue trapped in the brain or spinal cord lined by keratinized, stratified squamous epithelium supported by a connective tissue stroma.
Epidermoid cysts are similar to follicular dermal cysts and contain desquamated epithelial cells, keratin, and cholesterol. Dermal cysts also contain adnexal structures, such as sebaceous and apocrine glands, hair follicles, and fat.
breed predisposed to AAI
Yorkshire Terriers, Pomeranians, Miniature and Toy Poodles, Chihuahuas, and
Pekingese
Congenital
abnormalities contributing to atlantoaxial joint instability
- dens aplasia, hypoplasia, dorsal angulation or degeneration
- failure or absence of ligamentous support
- incomplete ossification of the atlas or block vertebrae.
mouvement atlanto-occip and antlanto-ax articul
atlanto-occipital: articulation of the cranial articular fovea of the atlas and the occipital condyles.
vertical head movements
atlanto-axial: caudal articular fovea are located on the dorsal aspect of the body of the atlas and articulate with the modified articular processes of the axis.
rotary head movement.
Name of separate area of ossification at the apical aspect of the dens + date of ossification
protalas
3-4m
ligts of atlantoaxial artic
transverse
apical ( to the basioccipital bone)
2 alar ligaments (occipital condyles)
+ joint capsule of the atlantoaxial joint and the dorsal atlantoaxial membrane, which extends between the arches of the atlas and axis
greatest stabilizing force of the atlantoaxial ligaments were the alar ligaments
signs associated with AAI
- Neck pain, some with a mild ataxia in 25%
- Ambulatory with a moderate to severe ataxia or paresis in 35%
- Nonambulatory paraparetic in 35% of cases
- Tetraplegic in 7%
Radiographic findings consistent with atlantoaxial subluxation
- dorsal displacement of the axis into the vertebral canal
- increased distance between the arch of the atlas and the spinous process of the axis
- hypoplasia, aplasia, or dorsal angulation of the dens
ventrodorsal or oblique rx can aid in evaluation of the dens
decrease in angle between the axis and the atlas: 162°
criteria for medical managment of AAI
minimal neurologic deficits
high-risk anesthetic candidates
minimal anatomic displacement
when finances prevent surgical intervention
patients with an acute history of neurologic signs
immature bones
62.5% (10 of 16) had a positive clinical outcome
dorsal/ventral surgical technic for AAI
dorsal: orthopedic wire, Kishigami Atlantoaxial Tension Band, use of the nuchal ligament, use of loops of suture from the axis to the obliquus capitis cranialis muscle of the occipital bone, and dorsal pinning
ventral: plates, positively threaded profile pins, screws, and Kirschner wires; many of the procedures are performed with and without polymethylmethacrylate
oxipitoataltoaxial malformation include …
agre + breed
prognosis
cervical vertebrae fusion, occipitoatlantal fusion, odontoid process and atlas hypoplasia, malformation of the axis, and atlantoaxial joint subluxation
< 2y, Saint Bernard, Cavalier King Charles spaniel, French Bulldog …
prognosis of OAAMs is considered guarded to poor
vertebral malformation more likely to be associated with neurologic deficits
ventral and ventrolateral vertebral body aplasia
cobb angle
intersection of two lines: one at the cranial aspect of the kyphotic vertebral segment and the other at the caudal aspect of the segment
neurologic dysfunction > 34.5 °
decrease expression of …. can cause neuropathic pain in syringomyelia
substance P
calcitonin
interleukine 6
main excitatory neurotransmitter for nociceptive pathway
glutamate (decrease by gabapentine, inhib alpha2delta subunit of Ca channel which is upregul in neurop pain)
Effect on location of endotracheal tube tie on atlanto-axial band in small breed dogs
Higher compression ratio with placement over craniocervical region
Female/male predisposition for spinal arachnoid diverticula?
Are all diverticula FLAIR hypointense?
male
yes
Which vertebral abnomality is associated with lombosacral stenosis in cat (54% of cases)?Is this factor associated with developpement of clinical signs ?
1/ Lumbosacral transitional vertebrae
2/ no
most common myelopathy in dogs <18m + most common affected breed
French bulldogs, pugs , crossbreeds , and English bulldogs
vertebral malformation (19%), SAD (13%), traumatic fracture of the vertebral column (10%), atlantoaxial instability (8%), and osseous-associated cervical spondylomyelopathy (8%).
IVDE accounted for 4.5%
factor assoc with VM: younger, screw-tailed, and pug breeds with chronic signs of T3-L3 myelopathy.
SAD : screw-tailed and pug breeds with nonpainful clinical signs.
IVDE: older, screw-tailed, and pug breeds with shorter duration of clinical signs.
