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. 2019 Aug 22;20(1):384.
doi: 10.1186/s12891-019-2754-2.

3D Spinal and Rib Cage Predictors of Brace Effectiveness in Adolescent Idiopathic Scoliosis

Free PMC article

3D Spinal and Rib Cage Predictors of Brace Effectiveness in Adolescent Idiopathic Scoliosis

Saba Pasha. BMC Musculoskelet Disord. .
Free PMC article


Background: Scoliotic braces are the standard of curve for management of moderate spinal deformities in pediatric patients. The effectiveness of this treatment method has been shown; however, the spinal and rib cage parameters, in the three anatomical planes, that are associated with bracing outcome in adolescent idiopathic scoliosis (AIS) are not fully identified.

Methods: A total number of 45 right thoracic AIS patients who had received a thoraco-lumbo-scaral brace for the first time were included retrospectively. For each patient, radiographic images at three visits, pre-brace, in-brace, and at least 1 year after the first brace fit were included. Age, sex, Risser sign, and curve type at pre-brace, and thoracic and lumbar frontal and sagittal Cobb angles, thoracic and lumbar apical rotations, sagittal and frontal balances at pre-brace and in-brace were determined. Two sagittal curve types (hypothoracolumbar and normal/hyperthoracolumbar kyphosis), two rib cage types based on the costovertebral joints (drooping and horizontal), and two axial shapes of the spine (S shaped and V shaped) were used to stratify the patients. Feature selection and linear regression with regularization determined the parameters and the interaction terms that predicted the brace effectiveness significantly.

Results: Smaller in-brace thoracic Cobb and larger in-brace lordosis predicted brace effectiveness, p < 0.05. Impact of the out of brace lordosis on the brace success increased as the in brace kyphosis angle decreased, p = 0.046. A larger out of brace lordosis in hypothoracolumbar sagittal profile type patients improved the outcomes, p = 0.031. A smaller out of brace thoracic rotation improved the bracing outcomes in patients with horizontal ribs, p = 0.040.

Conclusion: Both 3D patient specific parameters (lordosis, thoracic rotation, shape of the rib cage, and sagittal profile) and brace design (which allows larger in brace lordosis, better in brace Cobb correction) are important predictors of the brace effectiveness in AIS.

Keywords: Adolescent idiopathic scoliosis; Predictive model; Sagittal profile; TLSO brace; Transverse plane.

Conflict of interest statement

The author declares no competing interest.


Fig. 1
Fig. 1
Flowchart for patient selection and inclusion criteria
Fig. 2
Fig. 2
The 3D model of the spine and pelvis shown in frontal, sagittal, and axial views A) Out of brace, B) in-brace
Fig. 3
Fig. 3
The rib cage, sagittal, and axial subtypes. Rib cage subtype included A) Type 1: asymmetric or drooping ribs, B) Type 2: horizontal ribs. Sagittal subtypes included A) Type 1: normal/hyperthrocolumnar, B) Type 2: hypothoracolumbar (flat profile). Axial types included A) Type 1: S shaped axial profile in which the direction of the vertebral rotation changes in the thoracolumbar region, B) Type2: V shaped profile with one large curve extending to the lumbar spine: the direction of the vertebral rotation changes in lower lumbar. The vertebral level at which the direction of the vertebral rotation below the apex of the thoracic curve changes is shown by red rectangles
Fig. 4
Fig. 4
Example of patients with different rib cage, sagittal, and axial types. A) Axial Type1, Sagittal Type 1, and Rib cage Type 2. B) Axial Type2, Sagittal Type 2, and Rib cage Type1

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