Pulmonary sling. Roentgen observations

The bridging bronchus: A comprehensive review of a rare, potentially life-threatening congenital airway anomaly associated with cardiovascular defects

The bridging bronchus is a rare congenital airway anomaly in which the right upper lobe of the lung is supplied by the right main bronchus while the right lower lobe, and often the right middle lobe is supplied by an aberrant bronchus arising from the left main bronchus. The aberrant bronchus crosses (bridges) the lower part of the mediastinum, hence the term bridging bronchus (BB). This potentially life-threatening condition, usually accompanied by diffuse or focal airway stenosis, commonly presents with signs and symptoms related to large airway obstruction, such as respiratory distress, apnea, wheezing, stridor, and recurrent respiratory tract infections. Diagnosis of the BB is often challenging because the associated signs and symptoms mimic those of common conditions such as bacterial and viral bronchiolitis, bronchial asthma, cystic fibrosis, and foreign body aspiration. The BB is also often accompanied by congenital cardiovascular anomalies, including left pulmonary artery sling, atrial, and ventricular septal defects, tetralogy of Fallot, patent ductus arteriosus, and coarctation of the aorta. Patients presenting with the above signs and symptoms who are not responsive to standard treatment modalities, and have accompanying cardiovascular congenital anomalies should, therefore, be investigated for the BB. Herein, we review the anatomy, embryology, clinical presentation, differential diagnosis, imaging techniques and surgical management of the BB.

Left superior pulmonary artery sling

A pulmonary artery sling is formed when the left pulmonary artery originates from the right pulmonary artery and encircles the distal trachea, coursing between the trachea and esophagus to reach the hilum of the left lung. Pulmonary artery slings are often associated with distal tracheal narrowing, due to either intrinsic stenosis or secondary compression by the anomaly itself. We report a very rare case in which the left superior pulmonary artery originated from the right pulmonary artery and then acted as a sling, the left inferior pulmonary artery originated from the pulmonary trunk.

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.

Rare vascular anomaly mimicking bronchogenic carcinoma

We report a case of anomalous left pulmonary artery (pulmonary artery sling) detected incidentally on computed tomography thorax. This was carried out to rule out bronchogenic carcinoma in a patient of chronic obstructive pulmonary disease who presented with streaking. He was a chronic smoker having bilateral hilar prominence on chest radiograph.

Pediatric radiology in the Philadelphia region: a history of pedigrees and legacies

The specialty of pediatric radiology in the Philadelphia region has grown and evolved over the past eight decades originating from early "visiting" radiologists to Drs. Hope and Kirkpatrick, the "giants" of the 1950s and 1960s, to over 40 actively practicing pediatric radiologists. Clinical excellence, commitment to teaching, and advancement of knowledge through research remain the goals and ideals, much as they were many years ago. Philadelphia has been a fertile home and environment for this development, mostly because of outstanding leaders and role models who have trained and influenced generations of pediatric radiologists. The purpose of this article is to tell the story of this growth and development and to explore the intellectual origins, professional "genealogy," and legacies left by those who created this tradition.

An approach to the asymmetric neonatal chest radiograph

Conditions causing respiratory distress in the neonate, which may require surgery or an interventional procedure, typically have asymmetric radiographic findings. The findings are conveniently categorized from the plain radiographs as those producing a large lucent-appearing hemithorax, those producing a large cystic-appearing hemithorax, and those producing a large opaque-appearing hemithorax. Additional imaging with ultrasound, CT, MR imaging, or fluoroscopy can be planned based on the initial radiographic appearance.

Pulmonary vascular sling responsible for esophageal and tracheal obstruction. A case report

The disease of pulmonary vascular sling is a rare congenital condition. When it does occur it is often in conjunction with tracheal compression. The authors report herein a newborn with this anomaly presenting with a tracheal and esophageal compression.

Pulmonary sling: morphological findings. Pre- and postoperative course

Pulmonary sling (PS) is a congenital condition in which the left pulmonary artery (LPA) arises from the right pulmonary artery (RPA), forming a sling around the trachea causing tracheal compression. The incidence is not so rare as initially thought. Symptoms of severe airway obstruction often begin in the newborn or young infant. Echo-colour-Doppler may reveal the PS but emphysema can mask the typical findings. Deviation of fluid-filled lungs may be detected prenatally. Chest radiographs show unusual air distribution, deviation of heart and mediastinum and altered tracheobronchial angles. Bronchography and bronchoscopy demonstrate the high incidence of associated tracheal anomalies such as cartilagenous rings and long tracheal stenosis. Anterior oesophageal indentation is not always seen in the oesophogram. Magnetic resonance imaging (MRI) and computed tomography (CT) reveal the PS, but cautious interpretation is necessary because of different levels of the anomalous LPA. PS and associated cardiovascular malformations can be clearly detected by angiography. Associated extrathoracic anomalies are common. Early diagnosis and therapy of PS is mandatory and consists of reimplantation of the LPA into the pulmonary trunk and division of the ligamentum arteriosum. The postoperative course may be cumbersome necessitating bronchological interventions. Tracheal resection may be necessary but restenosis is frequent. A one-stage repair has been proposed in such cases and was successfully done in a few reported cases. Relief of respiratory obstruction is often complete when there are no associated tracheobronchial anomalies. Late postoperative course is favourable but respiratory obstructive attacks may occur with decreasing incidence over time and tracheal growth.

An unusual cause of intraoperative hypoxemia

Congenital anomalies of the tracheobronchial tree are rare occurrences; however, they can lead to pulmonary complications. A tracheal bronchus is an anatomic variant in which an ectopic bronchus originates directly from the tracheal wall above the carina. Presented is a case of intraoperative hypoxemia due to right upper lobe collapse. Despite what appeared to be proper endotracheal tube positioning, this clinical scenario was found to be the result of endotracheal tube obstruction of a tracheal bronchus supplying the right upper lobe. Fiberoptic bronchoscopy proved to be a rapid diagnostic and therapeutic tool, as the endotracheal tube was able to be visually positioned above this aberrantly located bronchus.

Rare types of aortic arch anomalies

Rare types of aortic arch malformations include isolation of the right or left subclavian arteries in conjunction with a left or right aortic arch respectively. Isolation of the innominate or carotid arteries and an aberrant left innominate artery may exist in association with a right aortic arch. Other anomalies are persistent fifth aortic arch, subclavian artery as the first branch of the aortic arch, pulmonary artery, and ductus arteriosus sling. The angiocardiographic features and embryology of each of these malformations are discussed.

Tetralogy of Fallot with severe pulmonary valvar stenosis and pulmonary vascular sling (anomalous origin of the left pulmonary artery from the right pulmonary artery)

A patient with the rare combination of tetralogy of Fallot with severe pulmonary valvar stenosis and pulmonary vascular sling is presented. The limitations imposed by pulmonary artery hypoplasia on the display of pulmonary vascular sling by conventional imaging techniques are discussed.

Pulmonary vascular sling: report of seven cases and review of the literature

A total of 130 cases of pulmonary vascular sling, including seven new cases in our collection, were studied. The sex distribution was 60% male and 40% female. The age at presentation was in the first year of life in approximately 90% of cases. Barium-esophagraphy showing anterior indentation was diagnostic in most of the cases. Bronchoscopy and tracheobronchography were useful in detecting associated tracheobronchial anomalies preoperatively. The analysis of 68 autopsied cases revealed associated tracheobronchial anomalies in 40% of the cases. Anomalies of the tracheobronchial tree took three major forms: abnormal distribution of cartilage in the walls of the trachea and major bronchi, intrinsic stenosis, and abnormal branching, the latter being that of bronchus suis. Acquired changes secondary in the sling resulted in compression of the major respiratory pathway by the anomalous left pulmonary artery. Major associated cardiovascular anomalies were present in 30% of the cases. These were represented by ventricular septal defect, atrial septal defect, patent ductus arteriosus, tetralogy of Fallot, common ventricle, and coarctation of the aorta.

Reconsideration of the anatomy of sling left pulmonary artery: the association of one form with bridging bronchus and imperforate anus. Anatomic and diagnostic aspects

In sling (retrotracheal) left pulmonary artery (SLPA), the tracheobronchial pattern is generally considered basically normal. Analysis of dissected specimens and/or bronchograms and other preparations from five studied and 32 reported patients suggests that there are two different forms of SLPA: (1) types 1A and B, with normal TB pattern [with (A) or without (B) a right pre-eparterial (tracheal bronchus)], and the aberrant left pulmonary artery causing TB compression. The tracheal bifurcation in type 1 SLPA is usually demonstrable at the fourth to fifth thoracic vertebral level; (2A) SLPA type 2A, with bridging bronchus (BB), in which condition the right main bronchus supplies the right upper lobe, but the bronchus supplying the right middle and lower lobes (the bridging bronchus) arises from the left main bronchus (LMB), posterior to which the SLPA courses; (2B) SLPA type 2B, with absence of the right bronchial tree, and the right lung (usually hypoplastic) supplied by a BB from the LMB, posterior to which the SLPA courses. SLPA types 2A and B have in common varying degrees of tracheal stenosis with abnormal cartilage rings and absent tracheal pars membranacea, abnormally low tracheal "bifurcation" (pseudocarina) at average level T6, increased bronchial angles with "inverted T" pattern, and lower level of anterior esophageal indentation by the SLPA than SLPA type 1. Imperforate anus occurred in 8/58 (14%) of patients with SLPA types 2A or B, but possibly in none with SLPA type 1. SLPA type 2 is the predominant form of SLPA, with the incidence of type 2B being twice that of type 2A.(ABSTRACT TRUNCATED AT 250 WORDS)

Demonstration of a tracheal bronchus by computed tomography

Computed tomography (CT) demonstrated a tracheal bronchus in a young child as well as the associated cystic disease of the right lung. Confirmation of the anatomical bronchial variant was obtained later when the cystic lesion was infected with aspergillus and surgically removed.

Asymptomatic form of left pulmonary artery sling

Eight patients with left pulmonary artery sling, which were asymptomatic at the time of the last consultation, are described: 2 adults and 1 child with no history of symptoms, 3 children with mild forms of airways obstruction and 2 patients with typical severe symptoms of airways obstruction in infancy. The mean follow-up of these 8 patients was 10 years (range 4 to 23), and in 1986, all were in good health and free of respiratory symptoms. The long-term prognosis is usually good.

Tracheal bronchus

Tracheal bronchus is an aberrant bronchus that arises most often from the right tracheal wall above the carina and is the result of an additional tracheal outgrowth early in embryonic life. Its incidence ranges between 0.1 and 5%. This anomaly usually is diagnosed incidentally during bronchoscopy or bronchography performed for various respiratory problems. Occasionally, it represents the underlying etiology for chronic pulmonary disease such as emphysema, atelectasis, and persistent or recurrent pneumonia, especially if it involves the right upper lobe and reflects an abnormal pulmonary clearing mechanism. Tracheal bronchus may be associated with other bronchopulmonary anomalies, tracheal stenosis, or Down's syndrome. In the absence of clinical symptoms, a diagnosis of tracheal bronchus does not require any treatment. In patients with recurrent right upper lobe disease and a tracheal bronchus, therapy should include resection of the aberrant bronchus as well as the lobe it supplies.

Cine CT diagnosis of pulmonary artery sling

This report documents the use of a Cine CT scanner for documentation of pulmonary artery sling. The examination can be carried out on outpatients and involves only a peripheral venous contrast injection. Excellent visualization of the anatomy is obtained.

Double right tracheal bronchus. A case report in an infant

An apparently unique case of double right tracheal bronchus supplying the whole right upper lobe is described in a 12-month-old infant presenting with a right paratracheal opacity, persisting cough, and ventricular septal defect. The two tracheal bronchi, initially discovered on tomography, were confirmed by tracheobronchography, which demonstrated also the absence of other upper lobe branches. At surgery, the upper lobe was atelectatic, and its blood supply was abnormal.

Tracheobronchography in the evaluation of anomalous left pulmonary artery

In three patients the diagnosis of an anomalous left pulmonary artery was confirmed when tracheobronchography demonstrated a discrete extrinsic impression on the proximal right bronchus. The diagnosis was unsuspected clinically in one patient with a hyperlucent left lung on conventional chest radiographs. In the other two patients there was a suspicion of a pulmonary sling, but findings on plain chest or airway radiographs were atypical. The tracheobronchogram can be a valuable procedure for diagnosing a pulmonary sling, detecting additional developmental anomalies of the bronchi, and predicting the post-operative clinical course.

Tracheal bronchus with regional ventilation and perfusion abnormalities

Tracheal bronchus is an uncommon anomaly of the tracheobronchial tree. In the case presented, clinical and pathophysiologic abnormalities were associated with this anomaly. The tracheal bronchus supplied the right upper lobe of the lung. The bronchus intermedius arose directly from the trachea in place of the right main bronchus. It was accompanied by marked regional changes in ventilation and perfusion. We discuss the clinical significance of this unusual anomaly.

Pulmonary artery sling

Pulmonary artery "sling" indicates the vascular anomaly wherein the left pulmonary artery arises from the right pulmonary artery and traverses between the esophagus and trachea to enter the left lung. Respiratory symptoms may result from compression of the trachea and right mainstem bronchus by the anomalous vessel as well as by associated tracheobronchial defects. Six cases are described. The distinctive radiologic features include anterior indentation of the barium esophagogram and a characteristic pulmonary angiogram. Surgery is the usual recommended treatment for life-threatening airway obstruction, but results are often poor. In patients with less severe symptoms the physician's approach may be modified by the presence of associated intracardiac defects and intrinsic airway disease.

Aberrant left pulmonary artery. Clinical and embryologic factors

The case of an infant with a pulmonary arterial sling (or aberrant left pulmonary artery) is presented. Associated congenital anomalies found in the original patient and in each of four other patients with this lesion, identified from postmortem files, are noted. The importance of associated anomalies of the respiratory tract is emphasized, since if present, they may affect the outcome after sucessful surgical correction of the vascular lesion. Previous theories of the embryologic origin of the anomalous artery are discussed, and a new theory is presented.

Anomalous left pulmonary artery with an unusual barium swallow

An atypical finding on barium swallow in a child with an anomalous left pulmonary artery causing obstructive emphysema in the right lung is described. The value of bronchography and need for early surgical intervention is stressed.

Case report: infantile sub-lobar emphysema and tracheal bronchus

Localised disturbance of aeration in children is as often the result of mucosal swelling due to infection as resulting from an inhaled foreign body. The present report adds another cause: tracheal bronchus. Elucidation of this cause of localised disturbance of aeration usually includes bronchoscopy, the anesthesia and direct trauma involved being highly undesirable if i infection is the cause. The case for limited, careful bronchography, before or instead of bronchoscopy, when the history of foreign body is lacking is presented.