The Non-Recurrent Laryngeal Nerve: a meta-analysis and clinical considerations.

Brandon Michael Henry,Krzysztof A. Tomaszewski,Jerzy A. Walocha,Silvia Sanna,Jens Vikse,Beatrice Sanna,Iwona M. Tomaszewska,R. Shane Tubbs,Matthew J. Graves

doi:10.7717/peerj.3012

Brandon Michael Henry, Krzysztof A. Tomaszewski + Show 7 more

Open Access

https://doi.org/10.7717/peerj.3012

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Abstract

BackgroundThe Non-Recurrent Laryngeal Nerve (NRLN) is a rare embryologically-derived variant of the Recurrent Laryngeal Nerve (RLN). The presence of an NRLN significantly increases the risk of iatrogenic injury and operative complications. Our aim was to provide a comprehensive meta-analysis of the overall prevalence of the NRLN, its origin, and its association with an aberrant subclavian artery.MethodsThrough March 2016, a database search was performed of PubMed, CNKI, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science. The references in the included articles were also extensively searched. At least two reviewers judged eligibility and assessed and extracted articles. MetaXL was used for analysis, with all pooled prevalence rates calculated using a random effects model. Heterogeneity among the included studies was assessed using the Chi2 test and the I2 statistic.ResultsFifty-three studies (33,571 right RLNs) reported data on the prevalence of a right NRLN. The pooled prevalence estimate was 0.7% (95% CI [0.6–0.9]). The NRLN was found to originate from the vagus nerve at or above the laryngotracheal junction in 58.3% and below it in 41.7%. A right NRLN was associated with an aberrant subclavian artery in 86.7% of cases.ConclusionThe NRLN is a rare yet very clinically relevant structure for surgeons and is associated with increased risk of iatrogenic injury, most often leading to temporary or permanent vocal cord paralysis. A thorough understanding of the prevalence, origin, and associated pathologies is vital for preventing injuries and complications.

Highlights

The Non-Recurrent Laryngeal Nerve (NRLN) is a rare variant of the Recurrent Laryngeal Nerve (RLN) that takes an aberrant course, not descending into the thorax as is usual (Fig. 1)
The NRLN usually results from partial regression of the fourth pharyngeal arch, resulting in an aberrant subclavian artery that runs behind the esophagus (Fig. 1B) (Wang et al, 2011)
We aimed to investigate the course-related consequences of the different types of NRLN, and the association of this variant nerve with the incidence of an aberrant subclavian artery

Summary

Introduction

The Non-Recurrent Laryngeal Nerve (NRLN) is a rare variant of the Recurrent Laryngeal Nerve (RLN) that takes an aberrant course, not descending into the thorax as is usual (Fig. 1) It was first reported by Stedman (1823). The NRLN usually results from partial regression of the fourth pharyngeal arch, resulting in an aberrant subclavian artery (arteria lusoria) that runs behind the esophagus (Fig. 1B) (Wang et al, 2011) This atypical vascular pattern permits the nerve to migrate freely into the neck as the fetus grows longitudinally (Wang et al, 2011). A thorough understanding of the prevalence, origin, and associated pathologies is vital for preventing injuries and complications

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