4 reasons to get a CT (which is better at looking at bone, while MRI's better for soft tissue)
- pre & post op spinal surgery (to check the anatomy and the hardware)
- characterization of osseous lesions (neoplasm/mets, hemangioma, osteoid osteoma, aneurysmal bone cyst)
- unable to get MRI (2/2 MRI contraindications)
CT - typically w/wo contrast? how about that ionizing radiotion?
- it uses ionizing radiation ... cancer risk for young pts
in what plane is the CT taken... then what?
axial - multiple slices are taken and can then be reformatted to sagittal and coronal pics
degenerative osteoarthritis of the joints between the centre of the spinal vertebrae and/or neural foraminae
congenital pars defect in axial view
it's a break in the pars articularis, btwn the sup and inf articular processes, so if it's bilat it leaves the post part of the vert floating post, elongating the spinal foramen into wine glass shape
how does a burst fx look on a lateral ct?
- the body looks smushed, all 4 walls are quite concave
- retropulsion into spinal foramen ((so you need to worry about impingement))
- the SP looks smaller
black dots = air in disc spaces bc of vacuum disc phenomenon
how does a burst fx look on an axial ct?
the body and the arch are mis-shapen, and the foremen is compressed by retropulsion, narrowing, stenosis
how does an osteopenic compression fx look on an lateral ct?
top of the vert body is compressed and broken -- so the top is mis-shapen and the bone has been pushed ant & post
how does osteopenia appear on a CT?
- loss of normal bony matrix
- instead the boe will look lucent and the vertical stripes of trabeculae will be accentuated
failure to stabilize the osteopenic compression fx --> ?
- more ant wedge deformity
- more retropulsion
- more kyphotic deformity --> all sorts of med issues
vertebral augmentation is for what? 2 types?
- palliation of pain rel to vertebral compression fractures
- 1) percutaneous vertebroplasty (PV)
- 2) balloon-assisted kyphoplasty
what's in conservative management of compression fxs?
conservative tx is the initial & gold standard tx
complications from nsaids (used for pain management in compression fxs)
compications from narcotics (used for pain management in compression fxs)
most pts w osteoporotic fxs have spontaneous resolution of pain within ___ from initial onset even ___
who qualifies for vertebral augmentation?
- pts who failed on conservative therapy for a compression factor due to --
- 1) pain frefractory to oral meds over 6-12 weeks
- 2) contraindications ot meds or requirement of IV narcotics & hospital admission
percutaneous vertebroplasty - what is it, what's used
- injection of low - viscosity cement directly into vertebral body using a uni or bipedicle needle
- PMMA biomaterial (used off-label)
percutaneous vertebroplasty - what's the success rate, who's most likely to do well?
- women & pts < 75 y/o
what might disqualify a pt from getting apercutanous vertebroplasty
- radicular pain involving lower extremities
- low back pain radiating to hips
bc there may be such canal compromise that the verteborplasty won't relieve sx
when are most compression fx pts given a PV? who's likely to get it earlier?
- 6-12 weeks after onset of pain
- pt w history of successful PVs
- pt requiring hospitalizaiton & IV narcotics for pain
when is canal compromise from posteriorly displaced bone not an absolute contraindication for a PV?
when there's no cord or nerve root compression or neuro symptoms
how often are there complications in a PV?
acute complications of PVs?
- cement leak (w/wo symptoms)
- cement pulm embolism (2/2 the needle entered a venous structure and put cement in there) w/wo symptoms
- neurological deficit (transient or permanent)
delayed complications of a PV gone bad?
fx at a new level (either bc the cement increases the risk of fx at nearby vert or bc it's the natural progression of osteoporosis)
- inflation of 1 or 2 balloons in a vert body, then filling them w high viscosity cement
- uni or bipedicle
comparison btwn balloon kyphoplasty & percutaneous vetebroplasty
- PV is cheaper
- no signif difference in outcomes or complications
- BK may offer better height restoration
- BK - may be better for things like a bad burst fx where it can offer more controlled angular & fracture correction w cement deposition
when is a CT myelogram needed? - the basic idea and 2 types of scenarios
- when you need ct delination of soft tissue structures within the spinal canal for...
- 1)pt who can't get MRI
- 2) pt w surgical hardware in spine which obsures spinal canal on MRI and CT scan
how is CT myelogram done?
injection of contrast material into thecal sac under flouroscopic guidance w subsequent CT imaging of the spine
this is less frequently done
contraind for CT myelogram
bleeding disorder (elevated PTT/INR)
indications for MRI
- soft tissue issues ---
- degenerative diseases
- osseous and extraosseous infection
- deymelinating/inflammatory diseases
- spinal post-op
absolute contraindications for MRI
- ferromagnetic aneurysm clip
- cardiac pacemaker
- orbital metallic froeign body, cochlear implant
relative contrainds for MRI
- metal fragments (depends on location -- the metal can warm up and burn an artery, but if it's in fat it's probably fine)
- 1st trimester pregnancy
- transcutaneous nerve stimulators
- severe claustrophobia
4 conditions that get non-contrast MRI
- lumbar back pain
- pre-op planning
a contraind for MRI contrast
pt w EGFR < 30 ... if it's lower there's a good risk for nephrogenic systemic fibrosis (NSF)
4 causes for contrast enhanced MRI
- post-op spine recurrent back pain eva - granuation tissue from recurrent or new disc herniation (differentiates btwn them)
- metastatic bone disease
- primary spinal cord lesions (tumor or demyelinating)
- spinal infection (itis of anything around there)