Evaluation of breast asymmetry in adolescent female patients with right-convex thoracic idiopathic scoliosis

English Keywords:Adolescent idiopathic scoliosis  Breast asymmetry  Anterior chest wall inclination  Female

English Abstract:

  【Abstract】 Objectives: To evaluate the breast asymmetry in female right-convex thoracic adolescent idiopathic scoliosis(AIS) and define its relationship with deformed components of the chest wall and spine in AIS. Methods: This study included 73 female AIS patients(average surgical age of 14.82±2.69 years, average Cobb angle 52.08°±11.68°) undergoing correction surgery during June 2010 and June 2011. There were 63 Lenke type Ⅰ and 10 Lenke type Ⅱ. The Image J software was utilized to manipulate formatted CT scans into 3-dimensional breast reconstructions so as to calculate the breast volume(BV). Both concave and convex parameters of breast shape were measured including the extraversion angle, the coverage angle, the axial breast height, the coronal breast height and nipple-to-sternum distance. The inclination angles of the concave and convex anterior chest wall were also measured. Breast asymmetry index(BAI) was defined as follows: (concave-convex)BV/[(concave+convex)BV]/2. Breast asymmetries were classified as being obviously different in size when BAI being either >5% or <-5%. The measurement of spinal deformity parameters involved the RAsag angle and the RAml angle. Paired t-test was performed to analyze the asymmetry of breast shape, and Pearson correlation analysis was utilized to define the correlation of the spinal deformity and the inclination of anterior chest wall with BAI. Results: The concave BV, the extraversion angle, the axial breast height and the coronal breast height(283.19±153.89ml, 26.32°±9.68°, 29.28±7.26mm, 17.42±6.35cm) was significantly higher than those of the convex side(257.42±149.85ml, 23.41°±8.24°, 27.88±7.70mm, 16.73±6.41cm, P<0.05) respectively, while the concave coverage angle and the inclination angles of the anterior chest wall(95.39°±8.42°, 57.61°±8.49°) was significantly lower than those of the convex side(106.34°±9.57°, 61.43°±6.73°, P<0.05) respectively. No difference was detected for the concave and convex nipple-to-sternum distance. The average BAI was 11.4%, and the concave breasts were objectively larger in 80.8% of the recruited patients. According to the classification of breast asymmetry, the obviously different bilateral breast size accounted for 78.1%, with the ratio of asymmetry beyond 10% being 52.1%(concave>convex) and 4.1%(concave0.05). The inclination angle of the anterior chest wall demonstrated significant correlation with the extraversion angle(r=-0.857, P<0.001) and the concave coverage angle（r=0.411, P<0.001), respectively. Conclusions: Majority of the right thoracic AIS patients was afflicted to some degrees by breast asymmetries, with the concave breast being larger, more extraversive and more concentrated than the convex breast. The variation of the anterior chest wall inclination introduced by scoliosis has a major influence on breast shape, suggesting a synergistic role of chest wall deformity and volume difference in the formation of breast asymmetry.