Anomalous bronchial arteries with surgically important relationships to abnormal recurrent laryngeal nerve and thoracic duct

Abstract

Listen

Translate article

Department of Anatomy and Cell Biology, Osaka Medical College, Takatsuki, Osaka, JapanStudies investigating the relationships between thebronchial arteries and left recurrent laryngeal nerve(LRLN) or the thoracic duct (TD) and more impor-tantly, the clinical relevance of such relationships areseemingly very rare. Based on text books of anat-omy (Standring et al., 2008; Moore et al., 2010),there are usually two left bronchial arteries arisingfrom the thoracic aorta passing to the dorsal surfaceof left main bronchus and one right bronchial artery,which arises from the third posterior intercostalartery to the right main bronchus. However, thebronchial arteries that originate outside the areabetween the T5 and T6 vertebrae are anomalous orectopic (Yoon et al., 2002; Hartmann et al., 2007).In anatomy text books, it is always mentioned thatLRLN loops around the aortic arch during its upwardcourse toward the larynx.During the dissection of 25 cadavers, anomalouscommon bronchial artery trunk (ACBAT) arising fromthe distal aortic arch was detected in an 80-year-oldman who was suffering pneumonia shortly beforedeath (Fig. 1A and 1B). This artery was tortuous anddilated with a diameter of 2.7 mm. The LRLN loopedaround the ACBAT passing deep to it during itsupward course. The artery soon gave rise to terminalbranches which traveled along the walls of the leftmain bronchus, crossed the later ventrally towardthe carina where it terminated at the right mainbronchus. A right bronchial artery with diameter of1.1 mm originating from the third posterior intercos-tal artery and coursing toward the deep surface ofright main bronchus was observed (Fig. 1C and 1D).The TD crossed the posterior intercostal arterymedial and close to the origin of the right bronchialartery.Our report is a rare case of LRLN looping arounda tortuous dilated ACBAT with abnormal branchingpattern to the ventral aspect of the main bronchi,which is different from the literature (Hartmannet al., 2007; Standring et al., 2008). Understand-ing the clinical relevance of the variable anatomyin our case is essential for cardiothoracic surgeons,interventional radiologists and otolaryngologists. Abronchial artery with a diameter greater than 2mm is considered to be enlarged and may rupture(Chung et al., 2006; Hartmann et al., 2007).Therefore, the dilated tortuous ACBAT may ruptureresulting in severe hemoptysis (Yoon et al., 2002,Hartmann et al., 2007). Moreover, the ACBAT maybe injured during mediastinoscopy as a result of itsintimate contact with the carina (Shields et al.,2009). Ortner or cardiovocal syndrome is vocalcord paralysis due to compression of the LRLN byenlargement of heart and great vessels (Lee et al.,2006; Khaki et al., 2007). Accordingly, there is apossibility that the enlarged ACBAT may compressthe LRLN resulting in cord palsy and consequentaspiration pneumonia (Lee et al., 2006). In addi-tion, the LRLN may be damaged during emboliza-tion or ligation of ACBAT for hemoptysis treatmentor during other invasive procedures dealing withthe anomalous artery (Yoon et al., 2002; Shieldset al., 2009). In our case, the coursing of TD closeto the intercostal and right bronchial arteries maydamage it during the exposing of the intercostalartery for treatment of aortic aneurysm (Minamiet al., 2006) or during surgical procedures relatedto the right bronchial artery.