Inter-observer reliability of clinical measurement of suprasternal notch-nipple distance and breast ptosis

CONTEXT: Suprasternal notch-nipple distance and breast ptosis are two measurements that are often used in everyday plastic surgical clinical practice. Nonetheless, the reliability of standard breast measurements has never been tested. AIM: The aim of the present study was to test the inter-observer reliability of clinical measurement of ptosis and suprasternal notch-nipple distance. SETTINGS AND DESIGN: Six raters measured ptosis and suprasternal notch-nipple distance in 12 breasts on the same day. STATISTICAL ANALYSIS USED: Intra-class correlation (ICC) coefficients, the coefficient of variation (CV) and Bland–Altman plots. RESULTS AND CONCLUSIONS: The results show that there is certain variation between different raters. The ICC of average measures between raters is 0.92 for the ptosis and 0.94 for the suprasternal notch-nipple distance, that is, the agreement between different raters is high. According to the Bland — Altman plots, the overall assessment of the comparisons of measurements between the different raters shows that the direction of the mean differences is close to zero. This study shows that there is a good reliability for measurements of suprasternal notch-nipple distance and ptosis. Nonetheless, there is a slight inter-rater variability in the measurements. Even though standardised, measurement of breasts is not an exact science and care has to be taken when the measurements are performed. The surgeon should have this in mind when measurements are used in clinical practice to evaluate breasts and to choose the right surgical method, as well as when guidelines for indications for surgery are set up.