The triad of bridging bronchus malformation associated with left pulmonary artery sling and narrowing of the airway: the legacy of Wells and Landing.

Although noted in the 19th century, it was not until 1938 that Scheid published the combination of left pulmonary artery sling and narrowing of the airway due to annular tracheal cartilages. Unaware of these prior descriptions, and without a precise preoperative diagnosis, Willis Potts in Chicago performed the first successful sling repair in 1953. In 1976, Cohen and Landing described Scheid's combination of left pulmonary artery sling and stenosis caused by complete tracheal rings, and the term "ring-sling complex" was introduced by Berdon in 1984. Four years later, Wells and Landing noted characteristic tracheobronchial malformations associated with these lesions and proposed a classification that has been confirmed to be clinically relevant in recent cross-sectional imaging studies.