Retrospective Analysis of Immediate In-Brace Correction of Scoliosis Attainable in Patients with AIS


Adolescent Idiopathic Scoliosis (AIS) is treated in several ways, beginning with physical therapy and bracing, and then utilizing surgical correction if necessary. The effectiveness of bracing has been debated for many years, and there are few research studies that can provide a clear picture of how a brace influences the final magnitude of the curve, its rate of progression, or the reduction in surgical treatment needed after bracing.  A 2007 evidence-based review article found no clear advantage to bracing over observation in reducing the need for scoliosis surgery1.  However, the article highlighted the lack of uniformity in the studies it reviewed, and the high variability in the outcomes that it pooled. 
As these broad questions are evaluated, there are several focused questions that can be answered.  The first question would be how much curve correction can be expected from a brace while it is being worn?  If bracing treatment is to be evaluated, then one must first be able to distinguish effective from ineffective bracing.  There is no reason to evaluate the outcome of ineffective braces.  So there must be a standard set as to the amount of immediate curve correction that a brace delivers before any brace treatment can be labeled as effective or ineffective.  This study will attempt to develop that standard by collecting pre- and post-brace radiographs and measuring the amount of correction that is routinely achieved.
Other authors have outlined the appropriate criteria for evaluating brace effectiveness, but have not included immediate in-brace correction of the curve in their list of outcome measures2.  The amount of in-brace correction of the scoliosis that can be obtained in a well constructed brace has a strong influence on whether the treatment will be successful.  The goal of this study is to evaluate the radiographs of patients who have just had a brace applied, and to determine the amount of correction that is routinely achieved.

Methods and Materials

For this study, a population of European physicians who are very skilled at scoliosis bracing will be recruited to submit pre- and post-bracing radiographs of their patients.  These will be submitted electronically to the researchers who will ensure that they are properly de-identified and coded for tracking purposes.  American physicians who are experienced in measuring scoliosis radiographs will then measure these to determine the magnitude of the scoliosis Cobb angles before and after the application of the brace. The percent correction will be calculated using these two measurements.
If lateral radiographs are available, then the thoracic kyphosis and lumbar lordosis will also be measured using the Cobb Angle technique.

Inclusion Criteria

The physicians will be asked to submit radiographs of patients who meet the following criteria:
• They have Adolescent Idiopathic Scoliosis as determined by the Scoliosis Research Society Criteria.
• They will be between the ages of 10 and 18 years, and be at a Risser Stage of 0 to 2.
• Their scoliosis Cobb Angle will be greater than 20 degrees.
• The radiographs represent the first bracing treatment that the patient has ever received.
• Brace treatment will include rigid orthoses only, and not dynamic braces.

Exclusion Criteria

Once patient radiographs have met the inclusion criteria and have been submitted for this study, they will only be excluded if the radiographs are of such poor quality that they are not able to be confidently measured by the American physicians.

Analysis of Variables

The research data will be stratified in order to accurately make a conclusive and effective brace correction standard. The sub-groups will be based on Risser stage, curve magnitude before treatment, primary vs. secondary curves, gender, region of the spine (high thoracic, thoracic, thoracolumbar, and lumbar) and European region of the treatment center (by country).

Sample Size/Power Analysis

The average Cobb Angle of a patient beginning brace treatment for AIS is 25 degrees and at least 50% of this should be corrected by the brace.  If an alpha level of 0.05 is selected and this study wants to be able to show a difference between pre- and post-bracing measurement, then the sample size must be larger than 27 patients (using G*power statistical software, version 3.0).  Since this is a retrospective study that poses no risk to patients, a larger sample size of more than 100 patients will be the goal.


The goal of this study is to produce a standard for bracing that delineates the amount of correction of the scoliosis curve that should be able to be obtained using a rigid orthotic.

Risk to Patients

The only risk to patients would be the loss of confidentiality of their medical record.  To protect them from this risk, all radiographs will be de-identified and given a research code number. HIPAA laws from the United States will be followed at all times, and submission of images from patients in Europe will also comply with local laws in each country.

Benefit to Society

The benefit of this study is to set a standard for immediate in-brace correction of a scoliosis curve that can be used by future researchers to help determine whether bracing is an effective treatment for this condition.

Study Location

Data will be collected from Scoliosis centers around Europe, where doctors will select the radiographs of patients from their practice. The X-rays will be placed in an online drop box, accessible only to the primary investigator. The X-rays will then be measured by American spine surgeons and radiologists who are experienced in treating scoliosis.

Financial Considerations

The financial considerations will be small- radiographs will be submitted electronically to a drop box where they can be obtained by the researchers.  The investigators and contributing physicians will participate without compensation.  The cost of the electronic drop box is minimal, and will be paid by the primary investigator.


The scoliosis centers will be identified over the next 2 months, and the database will be constructed.  Retrospective collection of radiographs will then be completed over the next 4 months.  Finally, measurements will be taken by physicians in the US over the final 2 months, to complete the study in under one year


1. Dolan, Lori A. PhD; Weinstein, Stuart L. MD. Surgical Rates After Observation and Bracing for Adolescent Idiopathic Scoliosis: An Evidence-Based Review. Spine. Volume 32(19) Supplement, 1 September 2007, pp S91-S100
2. Richards B. Stephen MD, et al. Standardization of Criteria for Adolescent Idiopathic Scoliosis Brace Studies: SRS Committee on Bracing and Nonoperative Management. Spine. Volume 30(18), 15 September 2005, pp 2068-2075

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