Unraveling shoulder balance in scoliosis: a clinical and radiological analysis

Shoulder balance is an important parameter while assessing the scoliosis deformity from a patient as well as clinician's perspective following the treatment. While there is uniform consensus about the importance of shoulder balance in scoliosis patients, what constitutes shoulder symmetry is still debatable. The aim of the study was to evaluate radiographic and clinical parameters both for medial and lateral components of shoulder balance.

A prospective database of scoliosis was reviewed. Patient demographics and radiological parameters, including radiographic shoulder height, clavicle angle, T1 tilt, first-rib angle, coracoid height difference, and clavicle rib intersection distance, were recorded. Shoulder angle, axillary angle, neck trapezius angle, lateral and medial shoulder height, axillary height, and neck height were recorded for clinical parameters by two independent observers. SRS-22r score was used for patient-reported outcome measure.

57 patients (AIS = 31, EOS = 26) were recruited. Intra-observer and inter-observer reliability was excellent for both radiographic and clinical parameters. Most of the radiological parameter had poor-to-moderate correlation with clinical parameters except Radiological Shoulder Height with Lateral Shoulder Height (r = 0.6, p < 0.05) and First Rib Angle with Medial Shoulder Height (r = 0.6, p < 0.05) having strong corelations. On comparing EOS and AIS patients for radiographic and clinical parameters correlation, no significant difference was found between two groups. First rib angle, neck trapezial angle, and neck height were significantly higher in medial shoulder imbalance group, while coracoid angle, radiological shoulder height, coracoid height difference, and shoulder angle were significantly higher in lateral shoulder imbalance group.

The results indicated that radiographic parameters could only partially reflect the clinical appearance of shoulders. In surgical planning of deformity correction, both medial and lateral components of shoulder balance should be taken into consideration for both radiological and clinical parameters. Level of Evidence Diagnostic study, Level III.