What Constitutes Shoulder Imbalance in Adolescent Idiopathic Scoliosis? Aesthetic Threshold for Surgical Correction

To determine what constitutes clinical shoulder imbalance and the aesthetic unsightliness of the torso region in patients with scoliosis. How can it be measured? Shoulder imbalance is one of the most perplexing problems in scoliosis. There are no standard clinical or radiologic criteria for diagnosing shoulder imbalance, and hence its impact and prevention are poorly understood. This prospective cohort study aims to determine the clinical parameters in the torso region that are most aesthetically disfiguring in scoliosis, and the measures with their threshold values that can define shoulder imbalance.

Twenty-six consecutive patients with adolescent idiopathic scoliosis formed the patient cohort. Only preoperative clinical photographs (not x-rays) of these patients were used for the study. Forty random observers were asked to rate the shoulder disfigurement in these patients as acceptable or unacceptable. An independent researcher plotted and measured 10 different deformity markers on these photographs. Three regions of the torso, the neck, shoulder, and axillary region, were studied separately. Receiver operating characteristic analysis was used to determine significance of each measure.

The patients with unacceptable deformation had statistically significant values in each of the 3 regions. The patients with acceptable appearance also had several measures that proved significant. Threshold values for each of these parameters were established from the analysis.

Shoulder imbalance in scoliosis is defined based on 3 regions: the neck, shoulder, and axillary region. Each has a specific threshold for producing cosmetically unacceptable deformation and they can be measured on clinical photographs. Measurement of the shoulder level alone is less representative.