Γεώργιος Χ. Κελάλης

Ορθοπαιδικός Χειρουργός

Κλινική Σπονδυλικής Στήλης

Metropolitan Hospital

Εμβιομηχανικές Άρχες Κηδεμόνων

Without intervention, a curve is likely to progressbetween the time of detection and the time of

skeletal maturity

The risk of progression

• increases as the degree of curvature increases

• increases with the magnitude of the curve at the time of detection

• decreases with increased age at the time of detection

Nachemson et al, 1982

Younger girls (ten, eleven, or twelve years old) who had a curve of at least

30o at the time of detection had the highest likelihood of progression,

ranging from 90% to 100%.

Curves that are 20o

or less before the time

of skeletal maturity

are considered mild

and generally are

re-evaluated

every six months.

Curves that

• progress 5o to 10o in 6 months

• that are more than30o at the time of diagnosis

usually are treated with a brace, as early and intensive bracing is believed to preclude the need for an operation in most instances.

Ideally, braces should be prescribed

to patients with idiopathic scoliosis

with curves between 30o and 40o, or with curves less than 30o

who have a history of curve progression with a high risk for

continued progression

Edgar et al, JBJS, 1985

Kehl et al , Clin Orth, 1988

Lonstien et al. JBJS(Am), 1994

Nachemson et all, JBKS(Am), 1995

1894DARK AGES

MANY TYPES

OF BRACESMilwaukee

Boston

Stagnara

Chenneau

Charleston

Michel

Lyonese

DDB

ΠΕΠEtc.

21 EXPERTS

19 TLSO

2 MILWAUKEE

Combination of pressures applied to

the torso over a prolonged

period, brace treatment attempts to modify mechanically

the scoliotic spine morphology

and to control progression of spinal

curvature

Peterson et al, JBJS, 1995

The degree of spinal correction is related to many parameters such as • The flexibility of the spinal

curves

• The shape and stiffness of the brace shell

• The location, size and thickness of brace parts

• The strap tension adjustment

• The biomechanical properties of truncaltissues to transmit the brace forces to the spine

• The duration of brace forces applied on the torso

Pressure distribution and forces generated by braces on the scoliotic deformities were measured to characterize bracing biomechanical action on the torso

A flexible tissue matrix was developed, composed of thin circular sensors that measure the pressures generated at the entire skin-brace interface.

It was suggested that Boston brace action is limited mainly to specific regions of pressure

Measuring mean brace forces exerted locally by the brace found that correction of curves was not solely depended on the level of force applied by the braceThe patients with the greatest curves achieved little correction despite significant levels of applied force

Chase et al, Spine 1989

Measurement of

• magnitude,

• location

• and direction of pressures

generated by the brace and the forces present in the straps while the pts assumed different positions, proved that :posterior thoracic pads provided scoliotic correction and derotation and that brace interface pressure were present in all positions.

Low strap forces had scoliotic curves that progressed while in the brace, whereas those with high strap forces had a reduction in curvature.It was concluded that although high strap forces are necessary to ensure lateral and derotationalforces on the spine they also cause undesirable forces that induce lordosis.

An increase in strap tension by 50% resulted in an increase of 20% in the mean force exerted through the compression pads

Therefore it would seem that the effectiveness of the brace depends to a certain extend on how tightly it is adjusted and fastened Currently, there is no standardized strap tension at which the brace should be fastened to obtain optimal results

A great deal of variability in the strap tension also was found the patients were taking different positions regardless of how tightly the straps were originally fastened

Even when the

patients returned in

the standing position

after having

performed other tasks

these were also

significant decreases

in strap tension

Several authors

believe that the

Heuter-Volkmann

principle contributes

to the development

of adolescent

idiopathic scoliosis

(A.I.S.)

Machida et al, Spione, 1999

Dickson et al, JBJS, 1984

Stokes et al, Spine, 1996

Briefly stated, asymmetric loading or compression of the growth plates on the concave side of the curves inhibit growth leading to wedging of the vertebral bodies

Bracing a scoliotic

curve should, in

theory, unload the

growth plates on the

concave side of the

vertebral bodies

near the curve’s

apex

Growth stimulation leading to structural remodeling of the vertebral bodies, on the curve’s concave side may explain the improvement or lack of curve progression, as measured by Cobb angles, reported with successful brace management of A.I.S.

Evidencedemonstrating the biomechanical effects of the Hueter-Volkmann on the vertebral body growth in spinal deformities is lacking

The threshold and limit of the force magnitudes necessary for the Hueter-Volkmann principle to apply in A.I.S. have not been delineated

Frank et al Spine Journal, 2003

The purpose of this

investigation was to

determine whether

long-term brace

treatment stimulated

asymmetric

chondrogenesis in the

apical three vertebrae

Curve flexibility is an important predictor of successful brace

outcome.

Brace application

was a successful

treatment when

the initial

vertebral body

derotations were

maintained until

skeletal maturity

The efficacy of

brace treatment

in patients with

rigid curves was

strongly

questioned

The Prevalence and Natural History Committee of the Scoliosis Research Society decided to compare, with use of meta-analysis, the results of non-operative treatment of idiopathic scoliosis

The type of brace had a significant

effect on the outcome

although this effect was small compared

with the effects of other variables

The daily duration for

which the brace was

worn also had a

significant effect on the

outcome

Bracing for twenty-

three hours per day

was associated with

the highest rates of

success

The goal of brace treatment is to

prevent progression of the

scoliosis by:1. Correcting the lateral curve

2. Correcting the malrotation

3. Returning the torso to a balanced

position over the sacrum

4. Properly aligning the spine in the sagittal

plane

Trochanter PadLumbar Pad

•The length and position of the lumbar pressure pad is determined by applying

•pressure to the paraspinal muscle at the level of the lumbar apex of the curve and

every vertebral body with a segmental vertrebral tilt towards the curve.

•Added length must be estimated for patients with increased lumbar lordosis as this

results in an apparently shorter lumbar spine.

•If L4 and L5 are to be included in the lumbar pad, the pad thickness should be

tapered in this area so that a bridging effect between the gluteus and the upper

lumbar region do not occur

•A trochanter pad is

used to correct a stiff

lumbo-sacral curve and

to act as a lever arm for

the lumbar pad and/or

the axilla extension.

•It is usually placed on

the same side that L5

tilts toward.

•The length and position of the thoracic

pressure pad is determined from the

ribs which project downward from the

thoracic curve.

•The pad is positioned from the mid-illiac

crest roll level and extends superiorly to

include the rib of the apex vertebra.

•The pad should not extend above the

•rib of the apex vertebra.

•The thickness of the pad should not

extend to the posterior vertical

•trim line to avoid worsening thoracic

hypokyphosis.

•The thickness of the thoracic pressure

pad is determined by the severity of the

thoracic curve and the extent to which the

thorax is displaced from the center line.

•The pad should provide superior medial lift

to the ribs under the apex, thus the pad is

thicker at the bottom than at the top (a

triangle in cross section).

Thoracic Pad

Derotation PadAxial rotation is most efficiently corrected by using force

couples, that is using a pair of forces directed in opposite

directions working on opposite sides of the axis

majority of derotational corrective forces are built-in to

the brace.

Just as the lateral forces require a relief area

opposite the correcting force, rotational

forces require an area of relief so that the

spine can migrate axially to derotate.

These relief areas can be created by an

adjacent pad which draws the brace away

from the body as seen anteriorly or by

bending the brace away from the body as

seen posteriorly on the right

Anterior Lumbar

Derotation Pad

ASIS Derotation Pad

Because the ribs slope downward from back to

front, the anterior thoracic derotation pad will be

inferior to the posterior derotation pad on the

thorax to give the appropriate force.

Thoracic posterior derotational pads are not

recommended in patients who present with a

hypo-kyphotic or lordotic

thoracic spine.

Anterior Thoracic Derotation Pad

In order to keep the brace from twisting on the

pelvis, pads may be needed, in a force-couple

arrangement,opposite to the ones used for

derotation of the lumbar spine.

This can be accomplished by a pad anterior to the

ASIS on one side and by bending inward the

lower margin of the module posteriorly

ΕΥΧΑΡΙΣΤΩ