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

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

doi:10.7717/peerj.3012

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

PeerJ. 2017 Mar 21:5:e3012. doi: 10.7717/peerj.3012. eCollection 2017.

Authors

Brandon Michael Henry¹, Silvia Sanna², Matthew J Graves¹, Jens Vikse³, Beatrice Sanna⁴, Iwona M Tomaszewska⁵, R Shane Tubbs⁶, Jerzy A Walocha¹, Krzysztof A Tomaszewski¹

Affiliations

¹ Department of Anatomy, Jagiellonian University Medical College, Kraków, Poland; International Evidence-Based Anatomy Working Group, Kraków, Poland.
² Department of Surgical Sciences, University of Cagliari , Monserrato , Sardinia , Italy.
³ International Evidence-Based Anatomy Working Group, Kraków, Poland; Division of Medicine, Stavanger University Hospital, Stavanger, Norway.
⁴ Faculty of Medicine and Surgery, University of Cagliari , Monserrato , Sardinia , Italy.
⁵ Department of Medical Education, Jagiellonian University Medical College , Kraków , Poland.
⁶ Seattle Science Foundation , Seattle , WA , United States.

Abstract

Background: The 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.

Methods: Through 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.

Results: Fifty-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.

Conclusion: The 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.

Keywords: Anatomy; Arteria lusoria; Meta-analysis; Non-Recurrent Laryngeal Nerve; Recurrent Laryngeal Nerve.

Grants and funding

The publication of this manuscript was supported by the Faculty of Medicine, Jagiellonian University Medical College KNOW (Leading National Research Centre 2012–2017) funds. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.