Thoracic-Lumbar Flashcards
what % of patients with vertebral fracture have concurrent injuries?
what % are thoracic trauma? abdominal trauma?
45-83%
thorax:15-35%
abdomen: 6-15%
what % patients with vertebral fractures have fracture in other areas
14 - 48%
what % patients with vertebral fractures have multiple fractures and luxations along vertebrae?
15-20%
list plating methods to fix and treat spinal fracture
- LCP
- SOP
- spinous process plating (Auburn (metal), Lubra (plastic))
- spinal stapling and modified sequential fixation
- nonlocking lateral vertebral body (not really performed)
what are concerns/disadvantages of using spinous process to treat spinal fracture
- does not stabilize ventral compartments
- not as strong
- spinous could fracture
- device pull out
- ischemic necrosis
what are 4 proposed mechanisms of entry for FCE?
- direct penetration from NP of IVD into spinal cord or vertebral vessels
- remnant vessels within NP
- herniation portion NP into bone marrow of vertebral body with retrograde movement FC into internal vertebral venous plexus
- neovascularization of degenerated IVD
in De Rosio 2007, what % dogs with FCE have no MRI lesions?
21%
factors to implicate outcome/prognosis in FCE?
- cervical/lumbar intumescences SA with greater long term debilitation than lesion of white matter C1-C6, T3-L3
- unsuccessful recovery if MRI lesion to vertebral length ratio >/=2, also if no motor within 2 weeks
list surgical approaches to T-L spinal cord for treatment of IVDD
- dorsal lam
- hemilam
- pediculectomy
- mini-hemilam
- IVD fenestration
- partial lateral corpectomy
- percutaneous discecotomy
- endoscopic hemilam or corpectomy
- dorsal lam with osteotomy of spinous process
prognosis of nerve sheath tumor of spine?
Dogs:
- 1997 study, MST 1419 d
- if brachial plexus DFI 7.5 mo; MST 12 months
- if spinal nerve root @ IV foramen 5 months
Cats:
- 70d in one study
- 2190d in another study
what MRI features has been shown association/ prognostic indicator for outcomes of IVDD?
T2W hyperintensity:
> 3x length L2
(20% dogs with >3x length of L2 get ambulation)
what are some biomarkers to ID IVDD?
MMP-9
CK
protein tau
glutamate
oxytocin in CSF S higher with compressive myelopathies
what is a cholesteatoma?
epidermoid cyst lined by keratinized stratified squamous epithelium
is a subarachnoid diverticula a cyst? how do you treat?
no - no epithelial lining
steroid + sx - dorsal laminectomy or hemi than fenestrate diverticulum and marsupialize
prevalence of degenerative myelopathy? breed over-represented? genetic factors implicated?
1-5%
GDS, pembroke welsh, boxer, rhodesian, husky, mini poodle, chesapeake bay
missense mutation superoxide dismutase gene (SOD1); bernese - AT transition; cats - FeLV antigens
describe the simpler classification of fracture of spine?
focuses on 3 units: IVD, vertebral body, articular processes
so:
- failure of IVD
- fracture of vertebral body alone
- fracture of articular processes
> 1 of the three = surgery
what are good and bad candidates of external coaptation for spinal fractures
best:
small dogs, minimal neuro dysfunction (or normal nociception), intact vertbral buttress, lack of concurrent injuries
poor:
unstable fractures, noncompliant owner, cats, noncompliant patients
where do extradural synovial cysts originate from?
zygapophyseal joint
difference between synovial versus ganglion cyst?
synovial cyst - have synovium like lining of epithelial cells
ganglion - no lining, from mucinous degeneration of articular cartilage
breed/signalment for cervical synovial cyst? prognosis with sx?
young, giant breeds
excellent prognosis
what are the 3 long vertebral ligaments?
supraspinous
dorsal longitudinal
ventral longitudinal
what are the 3 short vertebral ligaments?
interspinous
intertransverse
yellow
which vertebrae is anticlinal?
T11
what muscle attaches to accessory process? what lays just ventral and cranial to tendon attachement?
longissimus lumborum
spinal nerve and vasculature
what is the usual presentation for vascular disorders of spine?
- usually focal deficit/asymmetrical
- most patients not painful
- Cinical signs usually regress within 24-72 hours.
list complications to dorsolateral approach to surgical treatment of TL IVDD? surgery for IVDD in general?
pneumothorax
hemorrhage/hematoma
transient neuromuscular dysfunction
scoliosis
worsen of neuro grade
myelomalacia
Urinary or fecal incontinence
describe types of dorsal lam?
funkquista A:
- remove spinous process, laminae, articular process, 1/2 dorsal pedicle of vertebrae
funkquista B:
- just remove spinous process and laminae
modified dorsal:
- remove laminae, spinous process, caudal articular process
what do you need to care for with drilling for dorsal lam?
cancellous bone not present in laminae that forms interarcuate space near the attachment of yellow ligament
what is success rate of medical management for TL IVDD?
varies - 80-88% ambulatory
43-51% non ambulatory
what are 3 emerging therapies for spinal cord injury due to TL IVDD?
autologous olfactory glial cell and other stem cell transplantation
N-acetylcysteine for oxidative stress
IV use polyethylene glycol (fuse severed axons)
what are success rates of partial lateral corpectomy and percutaneous discectomy?
PLC - 91.4% ambulatory 6 mo. post op
- only 52.8% improved at discharge
PD - 88% (with deep pain perception)
32% without deep pain perception
describe alternative pin placement for pin + PMMA for spin fracture? Advantages/disadvantages
unilateral pin more horizontal via lateral approach (between longissimus lumborum and iliocostal lumborum)
advantage: decreased dissection, easy closure
disadvantage: dont see alignment of ZPJ
(2nd exposure site)
what is sensitivity for radiographs to detect spinal canal penetration post-op spine fracture repair? sensitivity for CT?
Rads: 50%
CT: 100%
what is a hemivertebrae? what breed has higher lumbar frequency?
hemi - incompletely formed with wedge shape - frenchies
what is block vertebrae?
ivd space doesnt form - adjacent vertebrae fused
what is a butterfly vertebrae?
sagittal cleft with affected vertebral body
where do most extrarenal nephroblastoma occur? MST?
T10- L2
range 4 mo - 3 years
what % of spinal cord intermedullary tumors are primary?
2/3
what are the prognosis for spinal fracture surgery?
- TL?
- LS?
- Cervical
If Dp negative - 5% maybe walk
TL:
- good if pain present. 80-100% older studies
- conservative upto 85%-95% (case selection)
LS:
- very good prognosis
many good long term without surgery
- if peripheral tone absent - guarded
Cervical:
- good, overall return to function 70%
% of OSA in spine of dogs? MST for spinal OSA in dogs?
6.5%
MST (55-155 d)
Met rate for spinal OSA in dogs
40%
prognosis for spinal OSA in cat
low met rates in cats
88-518 days
(one cat sx + chemo 0 1705d)
what 4 factors positively affect CT (noncontrast) to ID IVDD lesion?
mulitplanar reconstruction
chronic history of IVDH
chondrodystrophic breed
mineralized disc present
Sensitivity for CT with contrast to ID IVDD
sensitivity 97% site
100% laterality
% dogs that regain neuro function post surgery for TL IVDD (presented without DPP)?
43-62%
what factors have been associated with outcome in dogs with surgical treatment of IVDD (TL)
old world:
- prognosis worse L3-L7 vs TL
- dog size (larger >15kg worse prognosis)
- type of herniations - protrusion worse> extra
- Frankel score
what is the vacuum phenomenon on radiographs of spine?
gas radiolucency within IVD space from degeneration
sensitivity of ID IVDD site on myelography?
74-98%
what are adverse effects of myelography?
seizures, myelopathy, apnea, cardiac arrhythmia, meningitis, subarachnoid hemorrhage, death
what % dogs with myelography get seizures?
10-21.4%
IVD is _____ intense on T1/T2W
hypointense
_____sequence can show signal void if lesion has hemorrhage
T2* (gradient echo)
_____sequence helps for low-volume disc
STIR or T2W (FLAIR)
what is the sensitivity of rads in ID osseous lesions for animals with spinal cord injury and spinal fracture?
79%
72%
what 2 radiologic factors negatively associated with outcome?
degree of dislocation (100% = poor prognosis)
axis deviation of column on rads (DV?)
disadvantages of MRI with spinal trauma?
manipulation to put in machine gently
contraindication = metallic fragments (generate heat and move)
what is recurrence rate of surgery for TL IVDD?
what is recurrence rate of medically management for TL IVDD?
sx: 15-20%
mm: 40%
what breeds have higher recurrence rates?
dachshunds
list 3 ways to potentially limit recurrence?
fenestration
laser disc ablation
chemonucleolysis (collagenase, chondroitinase ABC, chymopapin)
prognosis for cats with surgically addressed TL IVDD?
success rate 83%
to classify fractures of spine, what makes dorsal, middle, and ventral compartments?
dorsal : spinous process, laminae, articular process, pedicles, dorsal ligament complex (supraspinous, interspinous, ZPJ joint capsule, Yellow L)
middle: dorsal longitudinal ligament, dorsal annulus f, dorsal vertebral body
ventral: rest of vertebral body, lateral/ventral annulus f., nucleus pulposus, ventral longitudinal ligament
how many of above need unstable that need surgery?
at least 2
what makes a screw-bar-pmma construct?
-cortical bone screws bilaterally into transverse processes, 1 cm screw and head extend ventromedially
-smooth steinmann pin contoured to form āUā
-contour pin wired to screw head using ortho wire
proposed advantage of screw-bar-pmma construct?
avoid penetration of vertebral canal or transverse foramina
