Aspects of bracing in adolescent idiopathic scoliosis

Scoliosis is a three dimensional deformity of the spine, characterized by
lateral deviation in the coronal plane. As growth sets in this deformity can
increase. The amount of curvature is objectified on anteroposterior full spine
radiographs, by measuring Cobb*s angle. Cobb*s angle is defined as the angle
formed between a line drawn parallel to the superior endplate of one vertebra
above the curvature and a line drawn parallel to the inferior endplate of the
vertebra one level below the curvature. The Soliosis Research Society defines
adolescent idiopathic scoliosis (AIS) as a curve > 11 degrees. Curves of a
lesser magnitude have little potential for progression.

Once the curvature shows progression and exceeds a Cobb angle of about 20
degrees, chances are small that this curvature will disappear spontaneously.
Weinstein and Ponseti concluded in 1983 that curves between 40 and 50 degrees
progress after skeletal maturity. Non-operative measures therefore aimed at
preventing curves progressing to this magnitude. The risk of progression is
inversely proportional to the Risser grade or the age of the patient, and
proportional to the size of the curve. There is little epidemiological data of
the Netherlands available, but it is estimated that about 600 adolescents with
AIS are treated with a brace yearly, and around 5-10 percent are treated
surgically. Only 11 hospitals include the surgical treatment of scoliosis,
including Maastricht UMC+.

Brace treatment is intensive for the patient, as a minimum wear of 20 to 23
hours a day is mostly prescribed. There are several disadvantages of a brace.
Problems with clothing in summer and winter, sore skin, decreased mobility,
depressed pulmonary function (causing restrictions in the necessary physical
therapy) are the foremost problems of brace wearing. Since the brace corrects
the stature of the child, optimal fitting is of outmost importance. An over-
and or undercorrection can result in an imbalance in the coronal and or
sagittal plane. If the brace treatment is ineffective, and the curve magnitude
progresses above 50 degrees, operative approach is contemplated. Such an
operation, in which the vertebrae are anteriorly and or posteriorly fused over
a large distance, is substantial. There is a long postoperative course, with
several operative complications which may occur.6 Therefore optimal brace
treatment is of outmost importance to prevent progression to an extent that an
operation cannot be avoided.

The only treatment to prevent the -rather radical- surgery in AIS is also
intrusive. Brace treatment is intensive for the patient, as a minimum wear of
20 to 23 hours a day is mostly prescribed. In an age in which appearance is
everything, most patients in their puberty consider brace treatment as
unpleasant. Problems with clothing in summer and winter, sore skin, decreased
mobility, are all unpleasant for the patient. Until 2014, when Weinstein
published his results in the New England Journal of Medicine, there was no
proof of bracing being an effective intervention. Since evidence has been
provided, the quality of bracing is of outmost importance for the outcome of
brace treatment.

• AIS is a chronic condition of the back. Once the curvature shows progression
and exceeds a Cobb angle of about 20 degrees, chances are small that this
curvature will disappear spontaneously.2 There is little epidemiological data
of the Netherlands available, but it is estimated that about 600 adolescents
with AIS are treated with a brace yearly, and around 5-10 percent are treated
surgically. Only 11 hospitals include the surgical treatment of scoliosis,
including Maastricht UMC+.

The only treatment to prevent the -rather radical- surgery in AIS is also
intrusive. Brace treatment is intensive for the patient, as a minimum wear of
20 to 23 hours a day is mostly prescribed. In an age in which appearance is
everything, most patients in their puberty consider brace treatment as
unpleasant. Problems with clothing in summer and winter, sore skin, decreased
mobility, are all unpleasant for the patient. Until 2014, when Weinstein
published his results in the New England Journal of Medicine, there was no
proof of bracing being an effective intervention.3 Since evidence has been
provided, the quality of bracing is of outmost importance for the outcome of
brace treatment.

Our rationale for the study is multi-layered. Brace treatment is only effective
if the patient is compliant; an optimally constructed brace is not effective if
only worn for two hours a week. The Maastricht brace was developed to increase
compliance by optimizing wearability and therefore more comfort, while
obtaining the same pressure and therefore effect as the current golden
standard, the Boston brace. Initial results are promising and further effects
need to be objectified. There are many contributing factors in obtaining good
results in bracing. The contributing factors are determined as factors of
influence in the corrective possibilities and therefore end term results of the
M-brace. Because of small patient populations current literature does not
impart on these factors. There are many unknowns, and therefore different types
of braces, brace regimes, and sport (or physiotherapeutical) regimes aside the
different brace regimes. There is a differentiation between night braces, day
braces, 23 hour a day braces and thoracolumbar or lumbar braces. There is a
differentiation between brace renewal each year or only on indication
(non-optimal fitment). There is a differentiation between static and dynamic
bracing. There is no current proof which of the above is better. There are
several aspects of bracing which are only partly known or scarcely described in
current literature; motion analysis in patients with AIS with or without brace
is only investigated in small groups using older techniques. Pulmonary function
in brace has only been published with use of rigid braces, with no correlation
made to correction of brace or end term bracing results.4,5 If force
distribution changes before the usual time of brace renewal there might be an
indication to renew the brace before the normal time of renewal. If force
distribution is non-optimal during the night or during schooltime (sitting
position), there might even be an indication to reduce brace time in such
situations.

As thoracic parts of the Maastricht brace are flexible (semi-rigid) and custom
made, our hypothesis is that pulmonary function will be influenced by the brace
in a predictable manner. With an optimal fitment the pulmonary function should
approach normal population. If the pulmonary function decreases or changes
there might be an indication to change the brace regime or increase
radiological follow-up with the reasoning of increase of Cobb*s angle. The
pulmonary function in brace is not only important for comfort and wearability,
but also for training purposes in physical therapy and daily activities.

As the braces are worn for longer periods of time, 23 hours a day, usually
several years, we want wo objectify the pressure applied by the brace. The wear
effect or habituation on pressure is unclear, as is the pressure in different
situations. If the pressure in the brace is absent or minimal in full rest
(sleeping), there might be an indication to shorten the brace wearing time at
night. Furthermore if there is a change in pressure as the brace ages, this
might be indicative for fitting a new brace. Currently this is evaluated at the
outpatient clinic by the treating physician by means of assessment of fit. This
information could be objectified by pressure measurements in brace.

Optimal fitment of a brace should also result in better in-brace movement. Our
hypothesis is that an optimal fitted brace should result in motion analysis
without noticeable imbalance in the sagittal and or coronal plane, and
therefore comparable to healthy subjects (not in this study) as defined in
literature.7 Since the brace corrects the stature of the child, optimal fitting
is of outmost importance. An over- and or under correction can result in an
imbalance in the coronal and or sagittal plane, and therefore a change in
motion analysis. As we expect the brace to be optimally fitted, the hypotheses
is that the kinematics of the walking pattern, the spaciotemporal parameters
(such as walking speed, step length, ao) and measures of stability will be
better comparable to short term non-brace wearing (this study).

With this study we would like to develop an optimal conservative treatment plan
for AIS with use of the Maastricht brace, and more insight in the
pathophysiology of AIS and the effects (or effectiveness) of bracing. Optimal
brace treatment will result in a better success rate of bracing and therefore
prevent surgery in the adolescent child. The Maastricht brace has been in use
since 2011. Initial results are promising, however long- term results and
contributing factors are unclear. In developing an excellent brace and bracing
protocol we hope to optimize the results of conservative AIS treatment.

The study design is a prospective longitudinal cohort study.

We would like to include twenty-two patients. As there are approximately 10
patients per year with AIS treated conservatively with a thoracolumbar brace in
the MUMC+, the minimum inclusion period would be two years, and an average of
four years of brace treatment, in which we can collect the requested data and
measurements. The duration therefore is estimated at a six years total.

The setting of the study is in the outpatient clinic of the MUMC+. There will
be no clinical admission necessary as in line with current normal practice.

Included in appendix 1, table 1, is a flowchart to demonstrate the study design
(C1 formulier)

Nature and extent of the burden and risks associated with participation,
benefit and group relatedness: The burden associated with participation is as
follows (Table 1, Appendix 1):
1. An increase of time in every outpatient clinical visit to evaluate brace
compliance with use of the Orthotimer and Pressure Guardian (Appendix 2).
a. Reading the sensors (both the Orthotimer and Pressure Guardian) will take
place at the outpatient clinic and lasts about five minutes.
2. After an adequate brace placement of the initial brace there is an
additional pulmonary test (+-2 hours) and an additional motion analysis (+-2
hours). These tests are non-invasive, but they do however consume half a day in
total. These tests are to be repeated every year until endpoint of bracing at
full bone maturity.
a. In summary both the pulmonary tests and the motion analysis will be taken
every year and at start- and endpoint of brace treatment.
3. There is only one group of patients subject for these tests, there is no
control group. There are no risks of attending. Treatment with the Maastricht
brace and outpatient clinical controls are identical to current clinical
practice in adolescent idiopathic scoliosis.
4. Additional questionnaires (two) are filled in every three months at the
outpatient clinic. The average time investment is 15 minutes per visit.