LECTURE 4 - T/L and Scoliosis Flashcards
AP AXIAL L5S1 JOINT
uncommon
significance:
- to see L5/S1 joint post surgery or before. to see the articulation, frac, displacement
tech:
- 18x24 or 24x30 landscape
- in bucky
- suspend on respiration
pos:
- supine with sponge under knee
- AP
beam:
- males: 30 deg cephalad
- females: 35 deg cephalad
- at level of ASIS MSP
collim:
- inculde SI joints
- clse collimation
FOV:
- SI joints shown
- L5/S1 joint clear
exp:
- 70-75 kVp, 32-35 mAs, yes grid, 110 sid
LATERAL L5/S1 (SPOT VIEW)
common
sig:
- only necessary to do this when LATERAL LUMBAR doesn’t show L5S1 joint space
- spondylolithesis of L4 TO L5 OR L5 TO S1
- frac
- degeneration
tech:
- in bucky
18x24 Landscape
- gonadal shielding (check departmental protocols)
- suspend on respiration
- 80-85 kVp, >60 mAs (depending on hip width), 110 sid
- yes grid
pos:
- pt in lat recumbent
- interiliac line perp to IR (straighten the spine), if not, angle the beam parallel to interiliac line. so you can add sponges to achieve this
- flex knees
- place lead sheet behind pt back (absorb scattered photons) but don’t stuff it under pt!!!
beam:
- 4 cm inf to iliac crest and 5 cm post to ASIS
collim:
- skin surface
- tiht collimation
FOV:
- OPEN L4-L5 and L5-S1 joint space
ANTERIOR OBLIQUE LUMBAR
have to do both right and left (of whatever type of oblique you choose PA or AP)
sig:
- see facet joints with a upside view
- pars defects
- spondylolysis
tech:
- 35x43 portrait
- in bucky
- 75 kVp 40 mAs 110 cm
- with grid
- suspend on expiration
pos:
- make pt semiprone
- roll 45deg side (left and right) toward IR and support lower back with sponges
- pt stabilise themselves with flexed leg
beam:
- LCM at L3 (4cm above iliac crest) along midclavic line
Collim:
- T12- S1
FOV:
- l5/s1,
- Facet joints
- scotty dog
compare L/RPO and R/LAO
PO:
- AP
- easier for pt, better quality but annoying for rad
- you see the facet joints of the side closest to the IR
- downside view
- eg. RPO = right facet joints
AO:
- PA
- preffered due to ease of positioning as landmarks easier to guide
- visualise facet joints farther from IR (raised side)
- view upside view
- eg. LAO = right facet joints
POSTERIOR OBLIQUE LUMBAR
have to do both right and left (of whatever type of oblique you choose PA or AP)
sig:
- same as AO except now its a AP view and you see the downside views of the facet joints
- but you’ll be inspecting the anatomy closer to the IR
tech:
- 35x43 portrait
- in bucky
- 75 kVp 40 mAs 110 cm
- with grid
- suspend on expiration
pos:
- semi-supine pt
- rotate 45deg with spinal column ON MIDLINE OF TABLE
- place sponges on back to stabilise pt
beam:
- LCM L3 (4cm above iliac crest) along midclavic line
collim:
- tight
- LcM to ASIS
- 5cm lat of each spinal edge
FOV:
- L5/S1
- facet joints
- scotty dog
Distinguish the components of the scottie dog
Nose = TP eye = pedicle front leg = inf AP ear = sup AP collar = pars
FLEXION/EXTENSION VIEWS
doc should be present
provides functional tests of of lumbar spine instability during flexion/extension
to see extent of spondylolisthesis
done before and after surgery
pos:
- just like lateral so can be done on table or erect
- flex and extend (2 projections)
How does DJD affect the facet joints - radiographic indicators?
effects esp L4/5
sclerosis
decreased space
osteophyte
subluxation
How does DJD affect IV disc - radiographic indicators?
L5/S1 disc is first to herniate usually since this region takes most pressure
effects esp L4/5
decreases height
vacuum disc
osteophytes
canal stenosis
body sclerosis
What’s spondylolysis?
frac or seperation of pars commonly at L5 with no displacement of vert
due to:
- chronic stress
- secondary to acute frac
- congenital defect of pars
radiographic indicator = scottie dog has a collar
What’s spondylolisthesis?
ant displacement of vert on top of vert below.
90% - L5/S1 but can occur any lumbar level
due to:
- pathological state of spine
- isthmic (natural frac causes it)
- progress from spondylolysis
- vert can be moving past each other too much causin mild low back ache to severe neurologic deficits
how is spondylolisthesis graded?
depends on how much the upper vert has moved in relation to bottom vert (div into 4)
grade1 : <25%
grade 2: 25-50%
grade 3: 50-75%
grade 4:>75%
How to asses the spine - imaging?
A (adequacy)
- is it appropriate to pt history and pt condition?
- necessary requirements reached for viewing?
A (alignment)
- don’t confuse a natural lordosis of L and kyphosis of S for pathology
- check alignment using vert lines
- 3 column rule
B(bone)
- BONY margins and internal trabeculae
- vert bodies (ie. height, shape, TP AND SP, scottie dog)
C (cartilage and joints)
- IV joint spaces (loss of height ad disc injury)
- facet joint articulation (must look parallel)
- interspinous spaces
S (soft tissue)
- psoas muscle shadow
- L1 to LT you should see a long triangular soft tissue shadow on each side of spine
- is it bulging?
What are the projections done for the thoracic spine?
AP
LATERAL
SCOLIOSIS - views
AP THORACIC SPINE
sig:
- to see C7-L1
- frac, solisosis/kyphosis, tumours, infections, congenital abnormalities
tech:
- 35x43 portrait
- yes grid
- in bucky
- exp: 70kVp 25 mAs 110cm
- suspend on deep inspiration or breathing tech
- decubitus filter over sup thoracic spine
pos:
- supine or erect
- erect: shoulders relaxed and arms by side wit pt back touching bucky.
no pt rotation.
distribute weight evenly - supine: midsag plane in line with midline of IR
flex pt knees with soles flat (reduce natural kyphosis of back)
rotation:
- SP in midline?
- pedicles equidistant?
beam:
- halfway between jug notch and xiphoid at MSP
- T7 (3-4” below jug notch)
collim:
- top of IR approx 5cm above shoulders to get T7 centred
- C7-L1 and soft tissue neck
FOV:
- air filled trachea
