Evaluation of cosmetic shoulder balance in Lenke type 1 and 2 adolescent idiopathic scoliosis across different observational perspectives.

BACKGROUND

Shoulder imbalance in patients with adolescent idiopathic scoliosis (AIS) contributes to a negative self-image and psychological distress, particularly in those with Lenke type 1 or 2 curves. Although previous studies have emphasized the significance of cosmetic shoulder balance (Sh.B) in informing clinical decisions and evaluating postoperative patient-reported outcomes (PROs), the observational perspective-a crucial factor-has often been overlooked in cosmetic assessment, potentially leading to inaccuracies and inconsistencies in measurements. Therefore, this study aimed to identify potential disparities in cosmetic Sh.B parameters across different observational points and to investigate their correlation with PROs.

METHODS

A total of 74 female patients with AIS and Lenke type 1 or 2 curves were included in this study. Full-spine radiographs were used to measure the following parameters: radiographic shoulder height difference (RSHD), first rib angle (FRA), clavicle-rib cage intersection (CRCI), coracoid process height (CPH), T1 tilt, clavicle angle (CA), clavicle-chest cage angle difference (CCAD), coronal balance distance (CBD), and Cobb angle. Cosmetic parameters, including shoulder angle (α), axilla angle (α), shoulder area index 1 (SAI), shoulder area index 2 (SAI), outer shoulder height (SHo), and inner shoulder height (SHi), were obtained from clinical photographs obtained from four different observation points: the anterior and posterior views at both the eye level and shoulder level. All patients completed the Scoliosis Research Society-22 (SRS-22) questionnaire preoperatively and at the 2-year follow-up.

RESULTS

As compared to eye-level measurement, shoulder level-measurement produced significantly larger α (1.77°±2.17° 1.11°±1.59°; P=0.029), α (-3.12°±3.01° -2.10°±3.22°; P=0.021), SHo (0.20±1.73 -0.19±1.44 cm; P=0.009), and SHi (0.95±0.62 0.29±0.59 cm; P<0.001) values. In the comparison between anterior and posterior Sh.B at the same level, the anterior α was significantly smaller than the posterior α (shoulder level: -2.09°±3.20° -3.12±3.01°, P=0.028; eye level: -1.71°±2.01° -2.10°±3.22°, P=0.037). Cosmetic parameters obtained from the anterior eye level and posterior shoulder level showed higher statistically significant correlations with preoperative SRS-22 scores (R=-0.413 to -0.207) and ΔSRS-22 scores (the change in SRS-22 scores from preoperative assessment to the last follow-up; R=-0.237 to 0.225), respectively.

CONCLUSIONS

Cosmetic measurements of Sh.B exhibited significant variability depending on observation point. Although cosmetic Sh.B measured from the anterior eye level may underestimate the patients' actual Sh.B, it more accurately reflects the patients' self-evaluation; meanwhile, cosmetic Sh.B evaluated from the posterior shoulder level better correlates with ΔSRS-22 scores during follow-up, suggesting its suitability in optimizing surgical strategies.