braces scoliosis

Thoracolumbar Thoracolumbar braces for the braces for the treatment of treatment of Adolescent Adolescent

Idiopathic ScoliosisIdiopathic ScoliosisGeorge Sapkas

Professor in OrthopaedicsGeorge Sapkas

Professor in Orthopaedics

Director of theOrthopaedic dpt for Spinal Disorders

&Musculoskeletal Diseases

Metropolitan Hospital

Director of theOrthopaedic dpt for Spinal Disorders

&Musculoskeletal Diseases

Metropolitan Hospital

Adolescent idiopathic scoliosis, as defined by the Scoliosis Research Society, is diagnosed when a lateral spinal curve of at least 11o is observed in a patient who is between ten years old and skeletal maturity

Natural historyNatural historyWithout intervention, the curve is likely to progress between the time of detection and the time of skeletal maturity; the risk of progression increases as the degree of curvature increases

Montgomery et al, Act. Orth. Scan, 1989

The risk of progression increases with the magnitude of the curve at the time of detectiondecreases with increased age at the time of detection

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%.

Nachemson et al, 1982

Current Options for Treatment

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 and those that are more than 30o at the time of diagnosis (considered moderate)

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

Curves of less than 30o rarely progress after maturity

but larger curves may continue to increase throughout the life of the patient

Weinstein et al, JBJS(am), 1994

Scoliosis’ correction with spinal instrumentation is the treatment of choice

for curves of more than 45o in children who are still growing, for curves of more than 60o in patients who have reached skeletal maturity, and for curves that have continued to progress even after treatment with bracing

Thoraco-lumbo-sacral Thoraco-lumbo-sacral orthosis (TSLO) orthosis (TSLO) is the most common is the most common non-operative non-operative treatment in treatment in progressive progressive adolescent idiopathic adolescent idiopathic scoliosisscoliosis

Ogilvie et al, Spine, 1994

By a By a judicious judicious combination of combination of pressures applied to pressures applied to the torsothe torso over a prolonged over a prolonged period, brace period, brace treatment attempts to treatment attempts to modify mechanically modify mechanically the scoliotic spine the scoliotic spine morphology morphology and to control and to control progression of spinal progression of spinal curvaturecurvature

Peterson et al, JBJS, 1995

The degree of spinal The degree of spinal correction is related to correction is related to many interconnected many interconnected parameters such as parameters such as

the correct ability the correct ability (or flexibility) of the spinal (or flexibility) of the spinal curves curves The shape and stiffness The shape and stiffness of the brace shellof the brace shellThe location, size and The location, size and thickness of brace partsthickness of brace partsThe strap tension The strap tension adjustment adjustment The biomechanical The biomechanical properties of truncal properties of truncal tissues to transmit the tissues to transmit the brace forces to the spinebrace forces to the spineThe duration of brace The duration of brace forces applied on the forces applied on the torsotorso

The effectiveness The effectiveness of bracing of bracing with a TLSO in the with a TLSO in the treatment of treatment of idiopathic scoliosis idiopathic scoliosis has always been a has always been a highly disputed highly disputed topictopic

Conflicting opinions Conflicting opinions in the literature in the literature stem from stem from inconsistencyinconsistency

In the patient In the patient population population

The evaluation The evaluation methods methods

Selection criteria for Selection criteria for treatment among treatment among different studiesdifferent studies

Ideally, braces Ideally, braces should be should be prescribed to prescribed to patients with patients with idiopathic scoliosis idiopathic scoliosis with curves between with curves between 3030oo and 40 and 40oo, or with , or with curves less than 30curves less than 30oo who have a history who have a history of curve progression of curve progression with a high risk for with a high risk for continued continued progressionprogression

Edgar et al, JBJS, 1985Kehl et al , Clin Orth, 1988

Lonstien et al. JBJS(Am), 1994Nachemson et all, JBKS(Am), 1995

By bracing scoliotic By bracing scoliotic curves that are not curves that are not likely to progress, the likely to progress, the brace may be brace may be erroneously deemed erroneously deemed effectiveeffective

Regardless of the better Regardless of the better understanding of the understanding of the prognosticators prognosticators for progression for progression of scoliotic curves, of scoliotic curves, brace treatmentbrace treatment still fails still fails and clinician disagree and clinician disagree about its usefulness about its usefulness

Aubin et al, Spine, 1997Carr et al, Spine 1989

Edelman et al, Act Orthop Belg, 1992Winter et al, Spine, 1986

In adolescent girls In adolescent girls with right thoracic with right thoracic curves between curves between 2525oo and 35 and 35oo the treatment with the treatment with a brace was a brace was successful successful in preventing in preventing progression progression of more than 6of more than 6oo

Nachemson et all, JBJS, 1995

Using computed Using computed tomography, tomography, demonstrated demonstrated significant significant vertebral vertebral derotation of derotation of scoliotic curves scoliotic curves treated with treated with bracesbraces

Aaro et al, Spine, 1981

When looking in long term When looking in long term effects effects of bracing found that the of bracing found that the Boston brace did not Boston brace did not improve, improve, but prevented, progression ofbut prevented, progression of

Vertebral rotation Vertebral rotation Translation Translation Rib humpRib humpCobb angleCobb angle

The immediate improvements The immediate improvements of Cobb angle and vertebral of Cobb angle and vertebral rotation were lost at follow uprotation were lost at follow up

Wilers et al., Spine 1993

Wrong indication for bracing due to Wrong indication for bracing due to magnitude of the scoliotic curve and magnitude of the scoliotic curve and

the type bracethe type brace

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

Chase et al., Spine, 1989Cote et al, Scol. Deform., 1995Jiang et al, Scol. Deform, 1992

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

Chase et al, Spine 1989

For the purpose of the studyFor the purpose of the study

A flexible tissue matrix A flexible tissue matrix was developed, was developed, composed of thin composed of thin circular sensors that circular sensors that measure the measure the pressures generated pressures generated at the entire skin-at the entire skin-brace interface.brace interface.It was suggested that It was suggested that Boston brace action is Boston brace action is limited mainly to limited mainly to specific regions of specific regions of pressurepressure

Cote et al, Scol. Deform., 1992 - 1995

Measurement of Measurement of magnitude, magnitude, location location and direction of pressures and direction of pressures

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

Jiang et al, Scol. Deform, 1992

It was found that patients It was found that patients with with low strap forceslow strap forces had had scoliotic curves thatscoliotic curves that progressed while in the progressed while in the bracebrace, , whereas those whereas those with high strap forces had with high strap forces had a reduction in curvaturea reduction in curvatureIt was concluded that It was concluded that although high strap forces although high strap forces are necessary to ensure are necessary to ensure lateral and derotational lateral and derotational forces on the spine forces on the spine they they also cause undesirable also cause undesirable forces that induce forces that induce lordosislordosis

Jiang et al, Scol. Deform, 1992

Clearly the Clearly the biomechanical actions biomechanical actions of the TLSO are still not of the TLSO are still not well understoodwell understoodConsidering that braces Considering that braces are prescribed are prescribed empirically, relying n the empirically, relying n the experience and experience and observations of the observations of the orthopedist and orthopedist and orthotist, it is possible orthotist, it is possible that treatment fails in that treatment fails in some patients because some patients because of the inadequate forces of the inadequate forces exerted by the braceexerted by the brace

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

Chase et al, Spine 1989

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

Jiang et al, Scol. Deform, 1992

Some patients were Some patients were wearing their braces wearing their braces less tight than less tight than others wereothers wereA great deal of A great deal of variability in the variability in the strap tension also strap tension also was found the was found the patients were taking patients were taking different positions different positions regardless of how regardless of how tightly the straps tightly the straps were originally were originally fastened fastened

Aubi et al, Spine 1999

Even when the Even when the patients returned in patients returned in the standing position the standing position after having after having performed other tasks performed other tasks these were also these were also significant decreases significant decreases in strap tensionin strap tension

Aubi et al, Spine 1999

Several authors Several authors believe that the believe that the Heuter-Volkmann Heuter-Volkmann principle contributes principle contributes to the development to the development of adolescent of adolescent idiopathic scoliosis idiopathic scoliosis (A.I.S.) (A.I.S.)

Machida et al, Spione, 1999Dickson et al, JBJS, 1984Stokes et al, Spine, 1996

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

Bracing a scoliotic Bracing a scoliotic curve should, in curve should, in theory, unload the theory, unload the growth plates on the growth plates on the concave side of the concave side of the vertebral bodies vertebral bodies near the curve’s near the curve’s apex apex

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

Lonstein et al, JBJS, 1994

Korovesis et al, Spine 2000

Evidence Evidence demonstrating demonstrating the biomechanical the biomechanical effects of the effects of the Hueter-Volkmann Hueter-Volkmann on the vertebral on the vertebral body growthbody growth in in spinal deformities spinal deformities is lackingis lacking

To our knowledge, To our knowledge, no longitudinal no longitudinal study of the study of the Hueter-Volkmann Hueter-Volkmann principle and principle and vertebral body vertebral body growth rate in growth rate in patients with A.I.S. patients with A.I.S. has been has been publishedpublished

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

Because the spine Because the spine simultaneously simultaneously experiences experiences compressive and compressive and tensile forces, tensile forces, it is unlikely that all it is unlikely that all compressive forces compressive forces inhibit growth inhibit growth and all tensile forces and all tensile forces stimulate growthstimulate growth

Adolescent idiopathic Adolescent idiopathic scoliosis bracing and scoliosis bracing and

the the

Hueter – Hueter – VolkmannVolkmann principleprinciple

Frank et al Spine Journal, 2003

The purpose of this The purpose of this investigation was to investigation was to determine whether determine whether long-term brace long-term brace treatment stimulated treatment stimulated asymmetric asymmetric chondrogenesis in the chondrogenesis in the apical three vertebraeapical three vertebrae

Successful brace treatment has been positively correlated with the total number of brace-wear hours per day Successful brace treatment may now also be positively correlated with the ability of the brace to initiate significant positional changes

Rowe et al, JBJS, 1986Howard et al, Spine 1998

Measurement error, as well as the lack of documented brace wear, may represent weaknesses of the study. Vertebral body rotation is notoriously inaccurate on unidimensional radiographs. A measuring error of 1 mm may significantly change a concave-to-convex height ratio.

Similarly, the radiographs on which the results were based ignore the three dimensional deformity of scoliotic curves.

In conclusion, the retrospective analysis of the data, compared with the prospective analysis, was more insightful in determining the importance of curve flexibility as a 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 questioned

A side-bending radiograph to assess curve flexibility may be cost effective in preventing TLSO application to patients, with rigid curves, unlikely to benefit from its use

Larger cohorts with spiral computed tomographs may someday elucidate whether the Hueter-Volkmann principle and vertebral body remodeling (if any) occur in brace-treated patients with AIS.

A Meta-Analysis A Meta-Analysis of the Efficacyof the Efficacy

of Non- of Non-Operative Operative

Treatments for Treatments for Idiopathic Idiopathic ScoliosisScoliosis

Dale et al, JBJS(Am), 1997

Graph showing the unadjusted mean proportions of success, with 95 per cent confidence intervals, for the twenty studies. LESS = lateral electrical surface stimulation.

Although bracing has long been the mainstay of conservative treatment of scoliosis, its efficacy has not been demonstrated definitively in prospective or randomized clinical studies in which it has been compared with other forms of non-operative treatment

The United States Preventive Services Task Force, in 1993, stated: “There is inadequate evidence to determine whether brace therapy limits the natural progression of the disease in a significant proportion of cases”

In a 1994 study of the long-term results of scoliosis screening in Dublin, noted: “Since the incidence of significant scoliosis and of surgery is independent of changes in bracing policy, the efficacy of bracing in causing significant change in natural history must be challenged.”

Goldberg et al, Orth. Trans. 1995-1996

In 1993, 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 selected three important variables for which sufficient information was available across studies:

the type of treatment,

the level of maturity,

the criterion used to determine progression of the curve (or failure of treatment)

The type of treatment was the most straightforward variable, as all of the patients had been managed

with bracing,

lateral electrical surface stimulation,

observation

For the purpose of analysis, the braces were subdivided into

Milwaukee braces, Charleston braces, and all other types of braces (primarily thoracolumbosacral orthoses),

and the bracing regimens were classified on the basis of whether the brace was worn for

eight, sixteen, or twenty-three hours per day

On the basis of the variables just cited, the studies were grouped into four categories according to the predominant level of maturity of the patients

Juvenile (composed of children who were nine years old or less), immature adolescent (composed mostly of children who were ten to thirteen years old and had a Risser sign of 2 or less), mature adolescent (composed mostly of children who were more than thirteen years old and had a Risser sign of 3 or 4), mixed (composed of a mixture of immature and mature adolescent patients, with no clear majority).

The criterion for failure ranged from 3 to 10 o of progression; the five studies in which no criterion was specified were classified as unspecified in the analysis. Progression of the curve was measured with use of the Cobb method in all studies

Bradford et al, Spine, 1983

The type of brace had a significant effect on the outcome (QB = 58, p < 0.0001; QW = 262, p < 0.0001), 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

The outcome was significantly influenced by the level of maturity as well (QB = 160, p < 0.0001; QW = 161, p < 0.0001). The weighted mean proportions of success were 0.99, 0.88, 0.71, and 0.60 for the studies of mature adolescent, mixed, immature adolescent, and juvenile groups, respectively

Graph showing the weighted mean proportions of success according to the level of maturity. Curves generally were less likely to progress as the level of maturity increased.

The criterion for failure also significantly affected the outcome Criterion for failure was 6o of progression; studies in which the criterion was 5o or 10o had higher proportions of success

This additional analysis also demonstrated that the type of brace had a significant effect on the outcomeThe weighted mean proportions of success were 0.99 for the Milwaukee brace

Graph showing the weighted mean proportions of success for the control condition and various bracing regimens. Braces that were worn for twenty three hours per day were significantly more effective than all other treatments (p < 0.0001). TLSO = thoracolumbosacral orthosis.

Conclusions Conclusions

The results of this meta-analysis support the efficacy of bracing compared with lateral electrical surface stimulation and observation only

Graph showing the weighted mean proportions of success for the control group and for the groups treated with lateral electrical surface stimulation (LESS) and bracing

Bracing for twenty-three hours per day was associated with the highest rates of success

The age of the patient at the start of treatment,

the criterion for failure,

and the bracing regimen

all had effects on the statistical model

In practice, the type of brace and the daily duration for which it is worn cannot be separated completely

These data were not adjusted to account for compliance of the patient with the prescribed period of brace wear. We can only state that when patients are told to wear the brace longer each day, they have a better chance of preventing progression of the curve