Poland syndrome: a new classification system based on a retrospective analysis of 74 cases

The aim of this study was to present a classification of Poland syndrome deformities, which we hypothesized was simple, valid, reliable and useful in planning surgery. We retrospectively reviewed 74 patients with Poland syndrome treated in our centre between 1990 and 2019 (inclusive). The proposed classification comprised six types of ascending severity and was based on clinical and radiological findings. Agreement with the frequently used but more complex Catena classification was substantial (kappa 0.70), and interobserver reliability was close to perfect (kappa 0.87). The severity of the deformities according to this classification correlated well with the number of surgeries performed, except for Type 5, in which the result of surgery often is disappointing, and in Type 6, that is beyond the reach of surgical treatment. We conclude that this classification is useful in planning surgery and in advising parents on the surgical strategy. Level of evidence III