Spinal Orthotics Flashcards
Orthotic Goals
- Correction
- Accommodation
- Stabilize
- Reduce Pain
Correction
- Flexible deformity
- Restore follower load
- Reduce moment
- Measure correction by measuring Cobb angle
Accommodation
- Fixed Deformity
- If you have a deforming moment, it is likely going to progress
Stabilization
- Local Stabilization
- Limit gross vertebral sway (ADLs)
- Decrease moment and increase carrying capacity
Reduce Pain
- Pain index scale
- Visual analog scale
Free orthosis
Orthosis is not impairing any motion control whatsoever
** Elastic binder
Stop orthosis
Part of the plane allows motion to occur, but the other part of the motion is stopped
** ex: specifically stopping extension but allowing flexion
Hold orthosis
- Limiting motion throughout the entire plane
- Ex: Burst fracture: greatest instability is transverse plan bc all soft tissue is on lax and you’ll have a lot of available rotation
Hold-Variable Orthosis
- Typically for transverse plane; “way out;” not a “true” hold
- allows micro movement within the orthosis
Biomechanics Principles of Spinal Orthoses
- End-point control
- Total contact
- Three point pressure system
- Kinesthetic reminder
- Increased Intracavitary pressure
End-Point Control
- Euler’s Theory
- Motion control of a free body
- Ultimately trying to increase the stability of a column (spine)
- Critical load: upper limit of load that the spine can withstand before bending
- When the critical load is less, the chance of progressing is greater
- The stable base is the pelvis
- The longer the length, the more stability we can impart
*** See the slide for critical load
How End-Point Control Applies
- If you saw a 10% increase in height for a given curve magnitude, you will automatically see a 20% decrease in critical load/spinal stability
- Gotta get something on that spine to restore stability
Total Contact
- Pressure = Force/Area
- You have to be able to re-distribute pressure to get aggressive stability –> if you don’t, you get skin breakdown
Three- Point Pressure
- 2 pressures going in an equal and opposite direction of the third (in between the two)
- Trying to limit motion
- Trying to encourage person to withdraw from a stimulus
- Used for someone who has a compression
What is the problem with 3 point pressure system
- Middle point (the opposite point) bc of a higher sheer to moment ratio right where the fracture is
◦ May address alignment but causes pain
What does the alternative 3 point pressure system have
- Bending Moment
Kinesthetic Reminder
- Kinesthetic
- Intact righting reflex
- Free orthotics help impart a kinesthetic reminder to withdraw from stimulus
- Will tell you if a design is indicated or contraindicated
Increased Intra-cavitary Pressure
- Trying to reduce discal pressure
- History: controversial bc they didn’t measure interstitial pressure
- can decrease discal pressure but not really sure what the mechanism is (is the orthosis creating load sharing?)
Optimal Sagittal Position
- Lumbar (hyper) extension for burst fracture, compression fracture, seatbelt fracture, disc herniation
- Lumbar flexion for spondylolysis, spondylolysthesis, central or lateral stenosis to reduce pressure on nerve roots
Cast Syndrome
Anything where you have a loss of extension or lordosis that draws superior mesenteric artery to the duodenum thus blocking it
Corset materials
- canvas
- cotton mesh
- elastic
Corset closures
- snap
- hook and eye
- pull straps/velcro
What is important to do with patients using a corset?
Need to watch them don and doff the device to ensure they can tighten it enough
* typically used by older patients, so arthritis may prevent them from putting it on properly
Biomechanical principles of corsets
- total contact
- kinesthetic reminder
- increased intracavitary pressure
- modified three point pressure system
Corsets - pathologies
- muscle strain
- post-surgical
- low back pain
- maternity (elastic in the front)
** pretty rare post-op
Research on corsets says:
- Least effective spinal orthosis for limiting gross trunk motion when compared to other devices
- Effects of reducing myoelectric activity in the paraspinal musculature has inconsistent results and needs further investigation
Components of contact spinal systems
- Kydex
- Polyethylene
- Copolymer
Openings of total contact spinal systems
- Overlapping
- Interlocking
- Posterior-opening
- anterior-opening
- often 2 piece because it is easier to don
Total contact spinal systems - biomechanical principles
- three point pressure
- end point control
- kinesthetic reminder
- increased intracavitary pressure
At what angle do we see significant axial load on the spine
30 degrees or higher
Total contact spinal system - donning/doffing
- in supine to reduce axial load of the spine
Sequence for tightening the straps of total contact spinal system
- Lay the person down before tightening can reduce the deformity
- Start with inferior strap to lock the orthosis onto the pelvis
◦ Facilitates better end point control
◦ Less problems with orthosis migrating up into axilla - Work up to the top strap
- Wait a few minutes for disco-elastic change
- Go back to bottom strap
Post surgical
- internal construct
- healing
- pain reduction
Do patients s/p idiopathic scoliosis get orthoses?
Not often because integrity of other structures is good
* typically used for neuromuscular scoliosis
If internal construct fails from scoliosis surgery, what motions is it typically from?
flexion and rotation
What gender does idiopathic adolescent scoliosis affect most?
Females > males (4:1)
Progression indicators for idiopathic adolescent scoliosis
◦ Skeletal maturity
‣ The more skeletally immature, the more likely it will progress
‣ Menarche to 18 mo later is typically the time of maturity cessation
◦ Magnitude of the curve
‣ Bigger the curve, the more likely it is going to progress
Orthoses options for idiopathic adolescent scoliosis
TLSO
CTLSO
TLSO is most effect for what?
curve apex T7 and below
- axilla limits how high you can bring it up
Types of data acquisition
- casting
- scanning: sit or lay down in a frame, get into corrected position then scan
What degree range is typically the curves that orthoses can help?
25-45 degrees
Mechanism to manage curves for idiopathic adolescent scoliosis
- curve correction
- end point control
- transverse load
- As degree of curvature increases, stability decreases
- 60 degree curve = almost no stability at all to the spine = not much we can do from an orthotics stand point
◦ Still likely to progress
◦ Likely need surgery - Looking for 60-70% correction in the brace
◦ When they stop using it, it progresses again until they reach skeletal maturity
Window for orthotic management
◦ Curve is very steep
◦ 30 degree curve is at 50% stability
‣ But if we can decrease it down to 20 degrees, we increase that stability to 80%
BRAIST Study Results
- 75% of subjects that wore an orthosis did not require surgery compared to only 42% in the observation group that did not require surgery
Wearing the orthosis BLANK hours per day is the same as not wearing an orthosis
0-6 hours/day
Wearing the orthosis greater than BLANK hours a day is overkill
> 18 hours/day
BRAIST primary study conclusions
- Bracing significantly decreased progression in high risk curves in AIS to the threshold of surgery
- Gains in benefit were seen with increasing hours of brace wear
** Dosage is the variable that had the greatest impact
Greatest influence on patient compliance regarding wearing of the orthosis
- Difficulty paying attention in school
- Emotional about having to wear orthosis
- Problems with eating
- Difficulty in sitting
- Breathing
- Look worse in clothes
Neuromuscular Scoliosis
- Can’t really change it.. trying to delay surgery
- Trying to restore overall balance
- Prevent curve from getting worse and improve physiologic function and ADLs
Review Spondylolisthesis
Review Burst Fracture
3 region coupling system
- Purely a bending moment, taking away the shear
- Decreases pain
- Great for kyphosis as well
