Origin and prevalence of the accessory phrenic nerve: A meta‐analysis and clinical appraisal

Abstract

The accessory phrenic nerve (APN) is a common anatomical variant with differing reports of prevalence in the literature. It can be injured during operative procedures to the neck and thorax or by regional anesthetic techniques in its vicinity. Our aim was to provide a comprehensive evidence-based assessment of the prevalence and origins of the APN. The databases PubMed, China National Knowledge Infrastructure, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science were searched comprehensively, followed by assessment of eligibility and extraction of data concerning the APN. The data were pooled into a meta-analysis. A total of 17 studies were included in the meta-analysis. Fourteen studies (n = 1,941 hemi-necks) reported data on APN prevalence resulting in an overall pooled prevalence estimate of 36.5%. Nine studies (n = 941 APNs) reported data on the origin of the APN. Most commonly the APN originated from the ansa cervicalis (16.5%) followed by the nerve to the subclavius (15.8%). Subgroup analysis on the basis of laterality and geographic region revealed no statistically significant findings. The APN is a highly variable anatomical structure present in over one third of the population, most often originating from the ansa cervicalis or the nerve to the subclavius. Clinicians need to be aware of the varying constellation of symptoms that can arise from APN injury. Ultimately, knowledge of APN variation could provide for better outcomes and reduction of iatrogenic injuries, particularly in high-risk patients prone to long-term complications from diaphragmatic dysfunction. Clin. Anat. 30:1077-1082, 2017. © 2017 Wiley Periodicals, Inc.

The Critical Appraisal Tool for Anatomical Meta‐analysis: A framework for critically appraising anatomical meta‐analyses

“…In this article, we introduced the CATAM rubric and used it to critically appraise a recently published anatomical MA (Kacprzyk et al, 2020). There have been other anatomical MAs recently published (Aldabe et al, 2019; Bellier et al, 2020; Berthaume & Bull, 2021; Cheruiyot et al, 2021; Dreher et al, 2018; Graves et al, 2017; Harvie et al, 2019; Koziej et al, 2020; Morelli et al, 2019; Nallikuzhy et al, 2018; Roberts et al, 2021; Sirico et al, 2019; Solewski et al, 2021; Stefura et al, 2018; Tomaszewska et al, 2018; Tomaszewska et al, 2018; Tomaszewski et al, 2017; Tomaszewski et al, 2017; Vikse et al, 2016a, 2016b; Whitley et al, 2020; Yammine, 2013, 2014b, 2014c, 2014d; Yammine et al, 2015; Yurasakpong et al, 2021). We believe that the running paper that we used is an exemplary anatomical MA (Kacprzyk et al, 2020).…”

Right hemidiaphragmatic paralysis after cervical transforaminal epidural steroid injection: illustrative case

“…Additionally, the presence of an accessory phrenic nerve (APN) is common and has been shown in 36.5% to 61.8% of phrenic nerves with variable origin, course, and communication with the respective phrenic nerve. 27 , 28 The most common origin of an APN was the ansa cervicalis, which arises from C3 and C4, or the nerve to the subclavius, which arises from C5 and C6. 27 , 28 Because of an unforeseen anatomical variation, direct needle injury to the phrenic nerve may cause permanent hemidiaphragmatic paralysis.…”

Anatomic Variation of the Phrenic Nerve and Brachial Plexus Encountered during 100 Supraclavicular Decompressions for Neurogenic Thoracic Outlet Syndrome with Associated Postoperative Neurologic Complications

“…In addition, 36% to 62% of persons can have an accessory phrenic nerve arising from the superior trunk of the brachial plexus, ansa cervicalis, or nerve to the subclavius. 3,7 What is more interesting is that the nerve and its accessory components, when present, seem to have a highly variable course as they traverse the outlet. To the surgeon operating in the thoracic aperture on a routine basis, locating the nerve in these areas is simply a mild inconvenience.…”