Ann Thorac Surg 2007;84:670-673
© 2007 The Society of Thoracic Surgeons
Case Reports
Robotic Division of an Unusual Variant of a Right Aortic Arch
Barbara L. Robinson, MDa,*,
Meena Nathan, MDa,
David W. Brown, MDb,
Christopher Baird, MDa,
Pedro J. del Nido, MDa
a Department of Cardiac Surgery, Children’s Hospital Boston, Harvard Medical School, Boston, Massachusetts
b Department of Cardiology, Children’s Hospital Boston, Harvard Medical School, Boston, Massachusetts
Accepted for publication January 29, 2007.
* Address correspondence to Dr Robinson, Bader 279, Department of Cardiac Surgery, Children’s Hospital Boston, 300 Longwood Ave, Boston, MA 02115 (Email: barbara.robinson{at}childrens.harvard.edu).
 |
Abstract
|
|---|
Anomalies of the right aortic arch are rare. Right aortic arch with remnants of various components of the left aortic arch and ductus can create a vascular ring resulting in obstruction of the aerodigestive tracts. This case report describes the rare form of retroesophageal left innominate artery with ligamentum between the base of the subclavian artery to the pulmonary artery, and the first time management by the novel robotic approach.
|
Introduction
|
|---|
The prevalence of vascular rings in general is 0.1% of the population as a whole, and 1.4% of those who have congenital heart defects [1]; this has been confirmed by findings in heart specimens of congenital heart defects. Right aortic arches (RAAs) occur in 0.1% of the population, and vascular rings in this situation result from remnants in the different components of the fetal left aortic arch, which fail to resorb [1]. One extremely rare variant [2] is that of a defect involving the ventral aspect of the persistent left aortic arch; this resulted in a right aortic arch, retroesophageal left innominate artery, with a left-sided descending aorta and ligamentum arising from the base of the left subclavian artery. This was addressed by a left robotic video-assisted thoracic surgical approach.
We report an unusual case of a symptomatic variant of an RAA that has not been previously addressed by using a robotic video-assisted thoracic surgical approach. A 6-year-old boy presented with progressive dysphagia. On physical examination he had equal blood pressures in all four extremities. A preoperative chest roentgenogram demonstrated discrete tracheal narrowing consistent with a vascular ring. Magnetic resonance imaging (MRI) with three-dimensional reconstruction was performed to delineate the anatomy. This revealed a RAA, giving rise to the right common carotid artery (CCA) and right subclavian artery (SCA), as well as a retroesophageal left innominate artery arising from a posterior diverticulum off the descending aorta, supplying both the left subclavian and left common carotid. The trachea and esophagus were compressed within the vascular ring (Fig 1A). The location of the ligamentum could not be ascertained on magnetic resonance imaging, and it could not be determined if there was any fibrous continuity between the left aortic arch and ascending aorta. Thus the differential diagnosis included either a double aortic arch or an unusual variant of a RAA.
View larger version (44K):
[in this window]
[in a new window]
|
Fig 1. (A) Left lateral view of the magnetic resonance angiographic image with three-dimensional reconstruction of the vascular ring depicting the right aortic arch variant. (B) Preoperative appearance of the right aortic arch, dorsal aspect of the left aortic arch, and the ligamentum arteriosum. (LAA = left aortic arch; Lig = ligamentous arteriosum; PA = pulmonary artery; RAA = right aortic arch.) (C) Postoperative diagram of the division of the ligamentum arteriosum.
|
|
To determine the precise anatomy, as well as to relieve the tracheoesophageal compression, we performed a robotic-assisted thoracoscopic division of the vascular ring with four standard left-sided video-assisted thoracic surgical incisions, which took approximately 2 hours. At exploration, a thick, taut ligamentous structure was identified, extending between the base of the left SCA and the left pulmonary artery, which was extrinsically compressing the esophagus (Fig 1B). The ligamentum and the diverticulum (which was emanating from the descending aorta) were dissected circumferentially. The ligamentum was then occluded proximally and distally with hemoclips and sharply divided, releasing any tension on the diverticulum (Fig 1C). The superior aspect of the diverticulum, revealed two large vessels, namely the left SCA and the CCA. There were no further ligaments coming off either one of these two vessels anteriorly; thus this was not a double aortic arch. Adhesion bands between the left-sided diverticulum and the esophagus were further divided to completely free the trachea and esophagus. The diverticulum itself was not divided. The patient was extubated soon afterward and was able to tolerate a regular diet. He was subsequently discharged on the following day and remains symptom free at 3 months.
|
Comment
|
|---|
By 5 weeks of gestation, six aortic branchial arches form between the ventral roots and dorsal aorta. The right fourth arch normally involutes and the left fourth arch persists as the aortic arch and proximal left SCA, with interruption of the dorsal segment of the right arch between the right SCA and the descending aorta, as well as regression of the ductus arteriosus. According to the hypothetical double aortic arch plan by Moes and Freedom [1], a RAA is due to the abnormal regression of the left fourth dorsal segment resulting in an aortic arch that crosses the right mainstem bronchus. In a clinical series of vascular rings, 54% to 68% of patients have a double aortic arch and 24% to 46% have RAAs [2]. A huge variability exists in the subtleties of the RAA, in the patterns of the descent of the descending aorta, and in the branching pattern of the brachiocephalic vessels [1]. Numerous systems of the complex development and regression of the aortic arches and their great vessel branches during fetal development have been described [1]. Variants of the RAA have been further subdivided specifically according to the origin of the brachiocephalic trunk, and there are four different areas of involution of either arch [2] (Fig 2A). Most RAAs have mirror-image branching (MIB) of the brachiocephalic vessels or an isolated aberrant left SCA arising from the proximal descending aorta behind the esophagus. The most common type of RAA (ie, mirror-image branching of the brachiocephalic vessels occurs if the defect occurs in segments A or B between the left subclavian artery and the descending aorta). If interruption in the left aortic arch occurs slightly more ventrally in segment C, this results in the left CCA emanating from the ascending aorta and the left SCA from the descending aorta. This particular anomaly is rare and only three such cases have been identified in the literature [3]. In two of the largest series, the incidence of RAA due to mirror-image branching ranged from 44% to 66% and from 34% to 56% due to retroesophageal left subclavian arteries [2] with no mention of cases of retroesophageal innominate artery reported in these series.
View larger version (17K):
[in this window]
[in a new window]
|
Fig 2. (A) Schema of primitive LAA and RAA with arch branches and ductus arteriosi. Segments A–D represent areas of potential arch involution. Involution of segments A or B, or both, result in RAA with MIB. Involution of segment C results in RAA with LCCA as the first branch of AscA and LSCA arising from DTA. Involution of segment D, as in our case report, results in RAA with LCCA and LSCA arising from a common trunk from the DTA. (B) Involution of segment D, as in our case report. (C) Postoperative appearance. (AscA = ascending aorta; DTA = descending thoracic aorta; LAA = left aortic arch; LCCA = left common carotid artery; LDA = left ductus arteriosus; LSCA = left subclavian artery; MIB = mirror image branching; PA = pulmonary artery; RAA = right aortic arch; RCCA = right common carotid artery; RDA = right ductus arteriosus; RSCA = right subclavian artery.)
|
|
Our case represents the interruption of the ventral segment of the left aortic arch, or segment D, between the left CCA and ascending aorta, with no regression of ductus arteriosus (Fig 2B). Theoretical mention of this defect is found in the literature [4]. This leaves a complete ring, with the first branch of the right arch as the right CCA, followed by the right subclavian artery, followed by the left brachiocephalic trunk (ie, the left subclavian artery and left common carotid artery) as a branch from a Kommerell’s diverticulum, which is a remnant of the left dorsal arch, passing behind the esophagus. In this case, the ductus arteriosus persisted on the left, connecting the left pulmonary artery to the base of the innominate artery, thus completing the ring. This differs from most cases reported in the literature in which either the location of the ductus was not mentioned or the ductus was attached to the descending artery rather than the base of the innominate artery as in our case [5]. The case elucidated by the first magnetic resonance image description [6] was operated on via a left thoracotomy. The surgeons found a right-sided descending aorta, unlike our left-sided descending aorta; furthermore there was no mention of the location of the ductus nor how the division was accomplished [7].
In summary, this is likely a new variant of a right aortic arch (RAA) approach through a robotic video-assisted thoracic surgical repair (Fig 2C). The unusual peculiarity of this case is that the ventral aspect of the left aortic arch had resorbed, which left a vascular ring consisting of an RAA, giving off two branches; the first and most proximal branch being the right CCA followed by the right SCA from the right-sided aortic arch anteriorly. Then this joined the descending aorta posteriorly. On the left, an aortic diverticulum gave rise to the left SCA and CCA, as well as the ligamentum arteriosum connecting to the LPA, which completed the ring. The arrangement of the brachiocephalic vessels resulted in compression of the trachea and esophagus. Thus it appears that in the RAAs there are three potential defects of the left aortic arch that can occur. The most ventral defect, as described in this case report, is probably the rarest of RAA anomalies reported so far, and is not mentioned frequently in other RAA series, particularly the position of the ligamentum emanating from the base of the diverticulum to the pulmonary artery. Surgical approaches in the literature have included standard thoracotomy, video-assisted thoracic surgery, or as in this case, a robotic approach. Minimally invasive approaches are part of our armamentarium in the repair of vascular rings at the Children’s Hospital Boston [8]. This unusual case of an RAA with a descending left aorta with ligamentum arising from the base of the left subclavian artery from the left retroesophageal artery was quite amenable to this robotic approach, which the child tolerated well.
|
References
|
|---|
- Moes CAF, Freedom RM. Rare types of aortic arch anomalies Pediatr Cardiol 1993;14:93-101.[Medline]
- Backer CL, Mavroudis C, Rigsby CK, Holinger LD. Trends in vascular ring surgery J Thorac Cardiovasc Surg 2005;129:1339-1347.[Abstract/Free Full Text]
- Konstantinov IE, Puga FJ. Surgical treatment of persistent esophageal compression by an unusual form of right aortic arch Ann Thorac Surg 2001;72:2121-2123.[Abstract/Free Full Text]
- Edwards JE. Anomalies of the derivatives of the aortic arch system Med Clin North Am 1948;32:925-929.[Medline]
- Garti IJ, Aygen MM. Right aortic arch with aberrant left innominate artery Pediatr Radiol 1979;8::48-50.[Medline]
- Midiri M, Finazzo M, Pilato M, Lagalla R, De Maria M. Right aortic arch with aberrant left innominate artery: MR imaging findings Eur Radiol 1999;9:311-315.[Medline]
- Moes CA, Mawson JB, MacDonald C, Smallhorn J. Right aortic arch with retroesophageal left aberrant innominate artery Pediatr Cardiol 1996;17:402-406.[Medline]
- Suematsu Y, Mora BN, Mihaljevic T, del Nido PJ. Totally endoscopic robotic-assisted repair of patent ductus arteriosus and vascular ring in children Ann Thorac Surg 2005;80:2309-2313.[Abstract/Free Full Text]
Top
Abstract
Introduction
