Right-sided aortic arch and aberrant left subclavian artery with or without a left nonrecurrent inferior laryngeal nerve

The Nonrecurrent Laryngeal Nerve Without Abnormal Subclavian Artery: Report of Two Cases and Review of the Literature

As a variant of recurrent inferior laryngeal nerve (RILN), the nonrecurrent inferior laryngeal nerve (NRILN) is closely related to the occurrence of abnormal subclavian artery (ASA). The nonrecurrent inferior laryngeal nerve has been found in patients without arterial abnormalities, which is seen in the coexistence of NRILN and RILN, but it is easily confused with sympathetic-inferior laryngeal anastomosis branch (SILAB). We encountered 2 right NRILN patients without ASA during thyroid surgery. This article summarizes the characteristics of these cases and proposes methods to distinguish the coexistence of NRILN and RILN from SILAB. So far, 11 articles have reported 16 cases of NRILN without arterial abnormalities. In patients without artery abnormality, the vagus nerve could send out a descending branch NRILN at the bifurcation of the carotid artery and enter the larynx after anastomosis with RILN. Adequate dissection of the carotid sheath may avoid confusion with SILAB, and neural monitoring is also expected to provide a reference for the identification.

A Computed Tomography Study on the Prevalence of Lusorian Artery Among Hungarian Adults

Introduction The aberrant right subclavian artery (ARSA), also called as lusorian artery (LA) is a developmental anomaly that exists in conjunction with a right non-recurrent laryngeal nerve (NRLN) in almost all cases. The average prevalence of such a vascular variation is estimated as 1%, although, studies have reported very different population means. Up to date, there is no available data on the frequency of this pattern in the Hungarian population. It can be treated as an indirect marker of a NRLN. Any preoperative information on the course of the inferior laryngeal nerves can help surgeons reduce the risk of an iatrogenic injury during thyroidectomies, especially in an environment where access to intraoperative neuromonitoring is limited. Objectives The primary aims were to determine the prevalence of an ARSA, predict the existence of an NRLN in the Hungarian population, and provide demographic analysis. Methods A retrospective, computed tomography-based study was carried out. Demographic description and statistical analysis were provided where applicable. Detected anomalous vasculatures were visualized with 3D segmentation, and images were interpreted. Results The imaging database review identified three patients with ARSA out of 686 eligible recordings, resulting in a frequency of 0.437% in the study population. All three patients were female and had a retroesophageal LA. Two of them had a Kommerell's diverticulum. One patient had common carotid arteries with a single origin. Conclusions The frequency of an ARSA and a concomitant NRLN among Hungarians fits into the results of recent meta-analyses. Preoperative assessment of this anomaly may reduce vocal cord complication rates of thyroidectomies.

Left Nonrecurrent Laryngeal Nerve: A Very Unusual Finding during Thyroid Surgery

Background

Identifying the inferior laryngeal nerve is one of the main concerns in thyroid surgery. The typical recurrent position occurs due the relative position between the vagus nerve and the larynx during the last 3 branchial arches development. In rare cases, this nerve does not loop under the right subclavian artery or the aortic arch. This abnormality is present in 0.7% of patients and is associated with the presence of anatomical vascular anomalies. The left non-recurrent inferior laryngeal nerve is an even rarer abnormality, with only six cases described in the literature to date.

Method

A 46- years old female patient referred to total thyroidectomy for symptomatic multinodular benign goiter.

Results

A left non-recurrent inferior laryngeal nerve was found with difficulty and then a partial thyroidectomy was performed. CT scan showed dextroposition of the vessels of the base of the heart and an aberrant left subclavian artery.

Conclusion

An association of a right-sided aortic arch and aberrant left subclavian artery, or the presence of situs inversus, although rare anatomical variations, are associated to a non-recurrent inferior left laryngeal nerve. Proper identifying these abnormalities may help to properly identify and salvage this structure.

Carotid Endarterectomy for a Patient with a Right-sided Aortic Arch and Aberrant Left Subclavian Artery Predicting a Left Non-recurrent Inferior Laryngeal Nerve: A Case Report and Literature Review

Cardiovascular malformations during embryogenesis can lead the inferior laryngeal nerve to branching directly from the cervical vagus nerve and entering the larynx. This rare anatomical variation is known as a non-recurrent inferior laryngeal nerve (NRILN), and increases the risk of accidental injury resulting in postoperative vocal cord paralysis during neck surgery. We report a case of an 83-year-old man who presented with left symptomatic internal carotid artery stenosis with a right-sided aortic arch and aberrant left subclavian artery (ALSCA). We performed carotid endarterectomy (CEA) using intraoperative neuromonitoring to avoid NRILN injury. To the best of our knowledge, this is the first report of searching for a left NRILN by electrophysiology during CEA. Neurovascular surgeons need to understand the variations of the NRILN associated with congenital cardiovascular anomalies and effective use of intraoperative nerve monitoring (IONM). We discuss the embryological origin, IONM, and surgical pitfalls of this case.

Anatomic classification of the right aortic arch

The term right aortic arch is used for an aorta that arches over the right bronchus. Right aortic arch was classified into two types by Felson et al, based on branching patterns, with a proposed embryological explanation, and into three types by Shuford et al. Other anatomical variants of right aortic arch were described later, including isolated left brachiocephalic artery and aberrant left brachiocephalic artery. We have classified right aortic arch anatomy into 10 variants, supported by radiological evidence, and with reference to possible embryology. This classification will help in understanding the morphological basis for the formation of different types of right aortic arch and the course of the recurrent laryngeal nerve in such cases.

Predictive value of ultrasound diagnosis of aberrant right subclavian artery with non-recurrent laryngeal nerve

Introduction

This study aims to evaluate the predictive value of color Doppler ultrasound for the diagnosis of aberrant right subclavian artery (ARSA) with a co-occurring non-recurrent right laryngeal nerve (NRLN).

Material and methods

In the present study, 58 patients with ARSA (ARSA group) and 1,280 patients without ARSA (controls) were diagnosed by ultrasonography. In addition, 32 patients with ARSA (ARSA operation group) and controls underwent thyroidectomy with surgical exploration with or without NRLN. Then, the incidence of NRLN was analyzed. The right common carotid artery (RCCA) and right subclavian artery (RSA) trends were observed by ultrasound, and classified into two types: RCCA and RSA originating from the innominate artery (IA) (type I), and IA could not be detected (type II).

Results

A total of 32 cases of NRLN were found in the ARSA operation group, but no case was found in controls, and the difference was statistically significant (p = 0.0006). The difference in the constituent ratio of type I and type II was statistically significant between the ARSA group and controls (p = 0.0002). That is, the IA could not be detected in the ARSA group, which was accompanied by the RCCA that originated from the aortic arch, while the IA was detected in most patients in the control group at the level of the sternoclavicular joints.

Conclusions

Aberrant right subclavian artery can be rapidly detected by ultrasonography. Aberrant right subclavian artery occurs when the RCCA originates from the aortic arch during detection. Patients with ARSA sometimes have co-occurring NRLN. Hence, vigilance in protecting the NRLN is needed during an operation.

Left non-recurrent inferior laryngeal nerve in a patient with right-sided aortic arch and aberrant left subclavian artery

Non-recurrent inferior laryngeal nerve (NRILN) is rare but one of the important anatomical variations in thyroid and parathyroid surgery. Almost all cases were observed on the right side with aberrant right subclavian artery and left NRILN have been reported in only five cases so far. Here, we reported a 38 year-old Japanese male with left NRILN accompanying adenomatous goiter. He was referred to our hospital for the surgical treatment of left thyroid goiter. Preoperative computed tomography revealed right-sided aortic arch and aberrant left subclavian artery with no signs of complete situs inversus viscerum, suggesting possible left NRLN. Left hemithyroidectomy was performed using nerve monitoring system. Intraoperatively, left recurrent laryngeal nerve was not identified along tracheoesophageal groove, but directly originated from vagal nerve and was running horizontally to larynx. Mobility of vocal cords were not impaired and postoperative course was uneventful. During thyroid surgery for the patients with right-sided aortic arch, meticulous care should be taken using nerve monitoring system to avoid nerve injury.

Right-sided Aortic Arch with Aberrant Left Subclavian Artery in a Pregnant Female: A Case Report and Literature Review

Right-sided aortic arch with aberrant left subclavian artery is a rare variant of vascular anatomy. Three types of right-sided aortic arches are described and classified based on the arrangement of the aortic arch vessels, the presence or absence of congenital heart abnormalities, the relationship of the aortic arch to the trachea and esophagus, as well as the presence or absence of a complete or incomplete vascular ring. On review of the existing literature, 31 case reports were found with a spectrum of clinical presentation sand outcomes. In this case report, we highlight a case of a young female in her early 20'swho presented with choking spells, shortness of breath along with intermittent dysphagia since childhood. She was otherwise healthy and pregnant at 26 weeks gestational age. A Computed tomography scan with angiography (CTA) of the thorax was performed to rule out a pulmonary embolism (PE) however surprisingly, a right-sided aortic arch with aberrant left subclavian artery was revealed instead. Subsequently, an extensive literature review was carried out to better understand clinical presentation sand treatment strategies for this rather rare disorder.

Right or left thoracotomy for esophageal atresia and right aortic arch? Systematic review and surgicoanatomic justification

INTRODUCTION

The optimal thoracotomy approach for the management of esophageal atresia and tracheoesophageal fistula (EA/TEF) with a right aortic arch (RAA) remains controversial.

METHODS

Systematic review of complications and death rates between right- and left-sided repairs, including all studies on EA/TEF and RAA, apart from studies focusing on long-gap EA and thoracoscopic repairs. Review of right- and left-sided surgical anatomy in relation to reported complications.

RESULTS

Although no significant differences were elicited between right- and left-sided repairs in complications (9/29 vs. 1/6, p = 0.64) and death rates (2/29 vs. 0/6, p = 0.57), unique anatomic complications - such as injury to the RAA covering the esophagus and intractable bleeding - associated with mortality were revealed in the right thoracotomy group. Left-sided repairs following failed repair through the right showed higher complications rate (3/3) than straightforward right- (9/29) or left-sided repairs (1/6) (p = 0.024). Right thoracotomies converted to left thoracotomies led to staged repairs more frequently (4/9) than straightforward right (5/38) or left thoracotomies (0/6) (p = 0.03).

CONCLUSIONS

There is not enough evidence to support that right thoracotomy, characterized by unique surgicoanatomic difficulties, is equivalent to left thoracotomy for EA/TEF with RAA. Both approaches might be required, and, therefore, surgeons should be familiarized with surgical anatomy of mediastinum approached from right and left. Systematic review, Level of Evidence III.

Congenital anomalies of the aortic arch

Congenital anomalies of the aortic arch include diverse subgroups of malformations that may be clinically silent or may present with severe respiratory or esophageal symptoms especially when associated with complete vascular rings. These anomalies may be isolated or may be associated with other congenital heart diseases. Volume rendered computed tomography (CT) and magnetic resonance angiography (MRA) help in preoperative surgical planning by providing information about the complex relationship of aortic arch and its branches to the trachea and esophagus. Three dimensional capabilities of both computed tomography angiography (CTA) and MRA are helpful in determining evidence of tracheal or esophageal compression or other high-risk features in patients with a complete vascular ring.

Successful Prediction of a Left Nonrecurrent Laryngeal Nerve in a Patient With Right-Sided Aorta and Aberrant Left Subclavian Artery

BACKGROUND

Left nonrecurrent laryngeal nerve (LNRLN) is an extremely rare anatomic variant. The development of such anatomic variation requires the regression of both the fourth (aortic arch) and sixth (ductus arteriosus, DA) arches on the left side. Preoperative prediction of this variant is difficult but might reduce risk of nerve injury.

METHODS

A 34-year-old female was indicated for thyroidectomy for a 2.4 cm follicular neoplasm and Graves' disease. Due to a positive medical history of 22q11.2 microdeletion and unexplained left vocal cord paralysis, a preoperative chest computed tomography (CT) scan was obtained and revealed a right-sided aorta (RSA) and aberrant left subclavian artery (ALSA) without Kommerell's diverticulum. A left-sided NRLN was then highly suspected.

RESULTS

Thyroidectomy was performed under general anesthesia with the utilization of intraoperative laryngeal nerve monitoring. A LNRLN was confirmed intraoperatively.

CONCLUSIONS

Right-sided aorta and ALSA indicate embryologic regression of the left fourth primitive aortic arch. The absence of Kommerell's diverticulum at the origin of the ALSA indicates the lack of high-pressure blood flow from the pulmonary artery to the ALSA through the ductus arteriosus during embryogenesis, suggesting the embryologic regression of the left sixth primitive aortic arch. The presence of all 3 radiologic features thus highly suggests the possibility of a LNRLN.