The Effect Spinal Bracing System on Gait in Adult Scoliosis Patients

Degenerative adult scoliosis (ADS) results from age related changes leading to segmental
instability, deformity and stenosis. Although the etiology is unclear, degenerative adult
scoliosis is associated with progressive and asymmetric degeneration of the disc and facet
joints, which typically leads to stenosis. By virtue of the narrowed spinal canal associated
with the degeneration these patients frequently develop back pain, as well as leg pain,
weakness, and numbness. With an aging population in the USA and an increased attention to
quality of life versus cost issues in the current healthcare environment, degenerative adult
scoliosis has become a considerable healthcare concern.

Patients with scoliosis demonstrate an altered gait pattern.Such differences include
decreased step length and reduced range of motion in the upper and lower extremities
asymmetry of trunk rotation and ground reaction force in three-dimensions. Previous research
found a decrease in the muscular mechanical work associated with an increase of energy cost
and a decrease in the muscular efficiency in a scoliosis population compared to healthy
controls. Furthermore, scoliosis patients exert 30% more physical effort than healthy
subjects to ensure habitual locomotion, and this additional effort requires a reciprocal
increase of oxygen consumption. This altered gait pattern demonstrated by subjects with
scoliosis may be due to changes in global postural control strategies caused by pain and the
spinal deformity.

Previous research showed that scoliosis patients do not have impaired postural balance when
compared to healthy controls, while several others did find an effect of scoliosis on
postural balance. This discrepancy in findings may be due to differences in curve
characteristics included and their effects on postural balance, curve types (single or
double), number of different curve types, location of curves (thoracic and lumbar), and/or
Cobb angles.

Bracing has been found to reduce pain within a short time in ADS patients. Custom-made rigid
torso braces, similar to those commonly used for children, are sometimes used in ADS
patients; however, only anecdotal evidence of their efficacy is available and problems with
comfort and compliance are quite frequent. A new brace has recently become available, the
Peak™ Scoliosis Brace (Aspen Medical Products), designed to alleviate pain in adult patients
with chronic pain secondary to scoliosis. The Peak Scoliosis Brace led to some improvement of
pain at 1 month in a group of adult women with scoliosis and chronic low back pain, but the
quality of life did not change significantly. This is may be due to the very short follow-up
time. The effect of these braces on functional tasks and activities of daily living including
walking have not been studied either.

The purpose of this study is to investigate the impact of spinal bracing using Peak™
Scoliosis Brace on pain and lower extremities kinematics of gait.

METHODS Design This study will be a repeated measurement design. This study will be a
non-randomized, prospective, concurrent control cohort study of patients with adult
degenerative scoliosis who are clinically indicated for brace intervention and will serve as
their own controls via their own pre-treatment evaluation. The proposal design is based on
highly recommended Bayesian Design along with the Bayesian and Gaussian analysis for such
population and sample size.

Sample Thirty candidates with symptomatic ADS will be enrolled. The sample size needed to
approach 80% statistical power for differences between conditions was estimated from the
literature.17,23,24 An effect size index of f = 0.50 was estimated. For a desired power of
80% (1 - β = 0.80) and desired α = 0.05, the effect size index requires a minimum sample size
of 26.

Inclusion/Exclusion Criteria Thirty spinal deformity patients will be enrolled.

Patients will be classified using the adult deformity SRS-Schwab system. Radiographs made
prior to brace treatment and at the two pre-defined follow-up points will be measured and
recorded for each patient.

Patients will report to the Spine Biomechanics Laboratory in the Texas Back Institute, be
educated on the study and will be asked to provide written informed consent after their
questions, if any, are answered. They will then be scheduled for a test session in the lab.
Each patient will be evaluated on 2 different occasions: first day of bracing, and 2±0.5
months post-bracing. Subjects will be fitted with 22 external reflective markers. These
markers will be placed based on those validated and published in the literature. A static
trial will be recorded with subjects positioned in a neutral, standing posture to create a
reference for defining neutral joint angles. Each subject will perform a series of
over-ground gait trials with self-selected speed. On all visits, subjects will walk 10
meters, stepping on three sequenced force platforms. Subjects will perform a series of gait
trials until five acceptable trials are obtained. In addition, each subject will perform 2
additional tests: 1. Timed up and go, and 6 minutes' walk test. After completion of
functional testing, the brace will be fitted to each subject by a spine orthopedic surgeon
before the testing. The subject will wear the fitted brace for at least 45 minutes prior to
retesting. The subject will then repeat the functional testing as mentioned above. Total time
required for each subject to participate in one session will be approximately 90
minutes.Three-dimensional (3D) kinematic data will be recorded at 120 Hz via a Vicon-Peak
system (Vicon Nexus 2.0 Inc.). Ground reaction force (GRF) (AMTI Corp.) data will be recorded
simultaneously at 1200 Hz. Spine, pelvis, hip, knee, and ankle kinematics and GRF will be
analyzed using a custom MATLAB program.

Clinical Data Collection Prior to each gait evaluation, patients will be asked to complete a
visual analog scale (VAS) to assess back and leg pain intensity, the Oswestry Disability
Index (ODI, version 2.1.a), a pain drawing to record symptom location. Patients will also
complete an SRS-22r, Fear Avoidance Beliefs Questionnaire (FABQ), and Tampa Scale for
Kinesiophobia (TSK) to record how their spinal deformity affects them across several physical
and psycho-social domains. Long cassette sagittal and coronal radiographs will be collected
at first visit before brace fitting to assess the extent of spinal deformity. As previously
stated, the deformity will be measured via the SRS/Schwab deformity classification system.The
bracing system to be used is the Peak Scoliosis Bracing System (Aspen Medical Product Inc.,
Irvine, CA).

The data will be analyzed with a repeated measurement two-way ANOVA to determine differences
between pre- and post-bracing measurements. A conservative alpha correction will be made
within each statistical family using Bonferroni correction for the multiple dependent
variables in order to avoid type I error. Data will also be analyzed to determine whether any
outcomes from the gait and balance analysis correlate with patient completed assessments
(pain scores) based on Pearson's R correlation.

Inclusion Criteria:

1. Age 30- 75 years and older

2. Clinically diagnosed thoracolumbar and/or lumbo-sacro-pelvic deformity as defined by
the SRS/Schwab classification systems as Cobb angle of 25° or greater

3. Able to ambulate without assistance and stand without assistance with their eyes open
for a minimum of 10 seconds

4. Able and willing to attend and perform the activities described in the informed
consent within the boundaries of the timelines set forth for pre-, and post-treatment
follow-up

Exclusion Criteria:

1. History of prior attempt at fusion (successful or not) at the indicated levels,
(history of one level fusion is not an exclusion)

2. Major lower extremity surgery or previous injury that may affect gait (a successful
total joint replacement is not an exclusion)

3. BMI higher than 35

4. Neurological disorder, diabetic neuropathy or other disease that impairs the patient's
ability to ambulate or stand without assistance

5. Major trauma to the pelvis

6. Pregnant or wishing to become pregnant during the study