Tracheobronchial Branching Abnormalities: Lobe-based Classification Scheme

Abstract

Boyden's nomenclature, which was based on postmortem specimens and published in 1955 prior to the advent of computed tomography (CT), is commonly used to describe the normal segmental bronchial anatomy and various abnormalities. However, several additional anomalies have been recognized since that time, and there is some confusion over the names used to describe these anomalies. Several congenital branching anomalies affecting the trachea, main bronchi, and intermediate bronchus have been reported, all of which can be recognized at chest CT but are often overlooked. These anomalies, which probably occur early in fetal life, can be either supernumerary, with defects occurring at 29-30 days gestation, or displaced, with defects occurring later. Tracheobronchial positional anomalies are often associated with other congenital abnormalities but may be isolated. They often are asymptomatic but can be responsible for pulmonary symptoms such as dyspnea, recurrent pneumonia, and hemoptysis. It is essential that these anomalies are recognized prior to lung resection to avoid complications, especially when video-assisted thoracoscopic surgery is performed. In addition, bronchoscopists should be aware of these anomalies before performing diagnostic or therapeutic bronchoscopic procedures. Awareness of a few key bronchial anatomic principles and use of a lobe-based classification scheme will facilitate recognition of tracheobronchial positional anomalies.

Association Between Tetralogy of Fallot and Tracheobronchial Branching Abnormalities: A New Clue for Pathogenesis?

“…Both observers were blinded to the congenital heart disease and to clinical and genetic data. For the diagnosis of TBAs (Figure), the classification proposed by Chassagnon et al was used Bronchial situs anomaly was defined as an unusual arrangement of the bronchial tree relative to the midline.…”

“…However, to the best of our knowledge, an association between TBAs and ToF has not been reported. TBAs are rare congenital anomalies that occur in 0.1% to 2% of the general population . Numerous TBAs have been described, and they must be differentiated from the frequent variations of the prevailing pattern of bronchial distribution .…”

“…TBAs are rare congenital anomalies that occur in 0.1% to 2% of the general population. 12,13 Numerous TBAs have been described, and they must be differentiated from the frequent variations of the prevailing pattern of bronchial distribution. 13 These abnormalities are often overlooked, but all congenital TBAs affecting the trachea, main bronchi, and intermediate bronchus can be recognized on chest computed tomography (CT).…”

A Study on the Patterns and Variations in the Tertiary Bronchi of Right Lower Lobe of Human Lung

“…A thorough knowledge about the anatomic principles of bronchial branching and use of a lobebased classification scheme will help in the recognition of tracheobronchial positional anomalies. 3 The objective of the present study was to determine the patterns and variations of the tertiary bronchi of right lower lobe. The right lower lobe was selected to be studied, because it is the commonest one affected in foreign body inhalation and aspiration.…”

Spanish multicentre study on morbidity and pathogenicity of tracheal bronchus in children

“…Other classifications distinguish between displaced and supernumerary bronchi, and between apical and lobar bronchi. Displaced TRB represents an anomalous cephalic location of the right upper lobe bronchus (RULB) or of any of its segmental bronchi, more typically the apical one (Figure ). When the RULB arises from the trachea it is known as “true tracheal bronchus” or “pig bronchus” since this is the normal anatomical pattern of swine and certain ruminants .…”