Orthoses For Spinal Deformity

Question 1

What is the primary goal of using orthoses for spinal deformity?

Answer 1

Prevent progression of deformity (via stabilizing the spine over the pelvis)

Question 2

What are 4 principles of stabilization for spinal deformity?

Answer 2

1. Endpoint control
2. Transverse load
3. Curve correction
4. Combined effect

Question 3

The design of a spinal orthosis for deformity depends on what factors (2)?

Answer 3

1. Level of deformity (curve)

2. Magnitude of deformity

Question 4

What are the two main goals for bracing AIS?

Answer 4

1. Prevent progression of deformity

2. Delay or prevent need for surgery (fusion)

Question 5

What are the criteria for bracing AIS?

Answer 5

25-40˚ curve with at least 2 years of remaining growth

Question 6

What effect does end-point control have on a spine?

Answer 6

End point control increases the critical load of a curve

Question 7

Based on Euler’s theoretical model, a column with one end fixed is __ times as stiff as normal? Both ends fixed?

Answer 7

A column is 8x as stiff with one end fixed and 16x as stiff with both ends fixed

Question 8

Transverse loading and correction of a curve increases the ___ of the spine.

Answer 8

Critical load capacity / Spinal load carry capacity

Question 9

A transverse load is directed where?

Answer 9

At the apex of the curve

Question 10

Does transverse loading or curve correction have a greater effect on increasing the critical load of the spine?

Answer 10

Curve correction has a greater effect, more important

Question 11

The effect of transverse loading and curve correction on critical load capacity is ___ for larger curves compared to smaller curves.

Answer 11

Reduced

Question 12

A 30˚ curve has what percent of normal critical load capacity?

Answer 12

50% of normal

Question 13

TLSOs for spinal deformity are typically worn how many hours per day?

Answer 13

18-23 hours per day

Question 14

TLSOs for spinal deformity can treat curves with apices as high as:

Answer 14

T7/T8*

Question 15

What negative effect did the mandibular/occipital extension on the original Milwaukee brace have?

Answer 15

Orthodontic deformities / pain

Question 16

What was the theoretical effect of a mandibular/occipital extension on the original Milwaukee brace?

Answer 16

Longitudinal distraction

Question 17

The mandibular/occipital extension of the Milwaukee brace was replaced with what component?

Answer 17

Neck ring (does not create distraction)

Question 18

What is the function of the neck ring on a Milwaukee brace?

Answer 18

Reduce sway of the vertebral column (keep upper spine centered over sacrum)

Question 19

What is the proximal constraint on a Milwaukee brace?

Answer 19

Neck ring

Question 20

Describe placement of the thoracic pad.

Answer 20

1. Over apical rib (rib that articulates with the apical vertebrae) and next inferior rib
2. Spans from medial aspect of paraspinal musculature to midcoronal line (posterolateral quadrant)

Question 21

What effect does thickening the thoracic pad posteriorly or contouring the bars of a Milwaukee brace inward have?

Answer 21

Increases anterior de-rotational force

Question 22

On a Milwaukee brace, what is the purpose of the anterior outrigger for the thoracic pad?

Answer 22

Keeps the strap away from the body anterior to the midcoronal line so as to keep force vector of the thoracic pad directed antero-medially. (Avoid counterforces)

Question 23

Describe adjustments to the Milwaukee brace for hypokyphosis.

Answer 23

Thoracic pad should be placed directly laterally (no anterior directed force).

Anterior outrigger can be shortened or eliminated.

Neck ring centered more anteriorly to induce kyphosis

Question 24

Describe adjustments to the Milwaukee brace for hyperkyphosis.

Answer 24

Pad placed over the apex of the kyphotic hump either floating (attached to a strap) or static (attached to the posterior uprights which can be contoured to increase force)

Question 25

Describe placement of the lumbar pad.

Answer 25

1. Inferior to the costal ribs and superior to the iliac crest
2. Directly over the apex of the curve in the posterolateral quadrant (midcoronal line to medial paraspinal muscles)

Question 26

What shapes are the thoracic and lumbar pads?

Answer 26

Thoracic - arc shaped (ribs)

Lumbar - triangular (contoured to waist)

Question 27

The pelvis girdle on a Milwaukee brace serves what functions?

Answer 27

1. Provide a foundation for the orthosis
2. Increase intraabdominal pressure
3. Provide a distracting force

Question 28

What identifies a primary curve?

Answer 28

Curve with the greatest mechanical stiffness

Question 29

In what order are primary and secondary curves loaded and shifted?

Answer 29

Primary curve loaded and shifted first, followed by loading of the secondary curve (with minimal shifting)

Double primary - shift and load curves equally

Question 30

What is the primary mechanism to reduce spinal curve magnitude?

Answer 30

Pad force

Question 31

What direction does the load vector point for thoracic and lumbar pads? What about with hypokyphosis?

Answer 31

Anteromedial (hypokyphosis - medial only)

Question 32

Where is the general location for thoracic and lumbar pads?

Answer 32

Posterolateral

Question 33

What determines the magnitude of force for thoracic and lumbar pads?

Answer 33

Maximum tolerable (evaluated clinically by redness and comfort)
Force < Skin Tolerance to avoid skin breakdown
Increase force if redness dissipates in 15 minutes

Question 34

Why does the orthosis need to be tightened / pads increased periodically?

Answer 34

Viscoelastic relaxation of soft tissues as curve reduces