New prognostic factors to predict the final outcome of brace treatment in adolescent idiopathic scoliosis.

STUDY DESIGN

Eighty-five patients with adolescent idiopathic scoliosis treated with Milwaukee or thoracolumbosacral orthoses at The Duchess of Kent Children's Hospital were studied longitudinally at 4-6-month intervals until maturity for spinal curvature and vertebral rotation, or until termination of brace treatment for persons who experienced brace failure who went on to have surgery.

OBJECTIVES

To identify radiologic features so that it may be possible to predict outcome of brace treatment early on.

SUMMARY OF BACKGROUND DATA

The structural curve with poor flexibility and large rotational prominence have been found to be associated with poor prognosis for brace treatment. However, early response to bracing for spinal deformity and its relationship to final outcome of brace treatment in a longitudinal study is not available in the literature.

METHODS

Vertebral rotation and Cobb angles measured from anteroposterior radiographs of the spine obtained before bracing and 1-2 months after bracing were found valuable for prediction. Changes in post-brace Cobb angle and vertebral rotation were considered as an increase or reduction only when there was an increase or reduction of minimum 5 degrees or more from their prebrace measurements.

RESULTS

Those patients who showed increase in vertebral rotation and/or in Cobb angle after brace application were shown to have progression of curves leading to brace failure in 93% of patients, and 79% of these required surgery. The patients with no change in both vertebral rotation and Cobb angle after bracing often experienced brace failure (69%). Two patients (15%) required surgery. The results show that reduction of both Cobb angle and vertebral rotation after application of a brace is a prognostic indicator for a good outcome (97%), and no patients required surgery. Most of the patients with lumbar scoliosis (91%) showed such reductions.

CONCLUSION

The findings show a strong association between changes in vertebral rotation and the Cobb angle after application of a brace and the final outcome. Reduction in both is indicative of a good outcome, whereas increase in one or both indicates brace failure.