Coexisting right nonrecurrent and right recurrent inferior laryngeal nerves: a rare and controversial entity: report of a case and review of the literature

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.

Systematic Review and Meta-Analysis: Recurrent Laryngeal Nerve Variants and Their Implication in Surgery and Neck Pathologies, Using the Anatomical Quality Assurance (AQUA) Checklist

INTRODUCTION

The recurrent laryngeal nerve (RLN) is the structure responsible for sensory and motor innervation of the larynx, and it has been shown that its lesion due to a lack of surgical rigor led to alterations such as respiratory obstruction due to vocal cords paralysis and permanent phonation impairment. The objectives of this review were to know the variants of the RLN and its clinical relevance in the neck region.

METHODS

This review considered specific scientific articles that were written in Spanish or English and published between 1960 and 2022. A systematic search was carried out in the electronic databases MEDLINE, WOS, CINAHL, SCOPUS, SCIELO, and Latin American and Caribbean Center for Information on Health Sciences to compile the available literature on the subject to be treated and was enrolled in PROSPERO. The included articles were studies that had a sample of RLN dissections or imaging, intervention group to look for RLN variants, or the comparison of the non-recurrent laryngeal nerve (NRLN) variants, and finally, its clinical correlations. Review articles and letters to the editor were excluded. All included articles were evaluated through quality assessment and risk of bias analysis using the methodological quality assurance tool for anatomical studies (AQUA). The extracted data in the meta-analysis were interpreted to calculate the prevalence of the RLN variants and their comparison and the relationship between the RLN and NRLN. The heterogeneity degree between included studies was assessed.

RESULTS

The included studies that showed variants of the RLN included in this review were 41, a total of 29,218. For the statistical analysis of the prevalence of the RLN variant, a forest plot was performed with 15 studies that met the condition of having a prevalence of less than 100%. As a result, the prevalence was shown to be 12% (95% CI, SD 0.11 to 0.14). Limitations that were present in this review were the publication bias of the included studies, the probability of not having carried out the most sensitive and specific search, and finally, the authors' personal inclinations in selecting the articles.

DISCUSSION

This meta-analysis can be considered based on an update of the prevalence of RLN variants, in addition to considering that the results show some clinical correlations such as intra-surgical complications and with some pathologies and aspects function of the vocal cords, which could be a guideline in management prior to surgery or of interest for the diagnostic.

The Influence of Breathing on the Central Nervous System

The functions of the diaphragm do not stop locally in its anatomy but affect the whole body system. The respiratory rhythm, directly and indirectly, affects the central nervous system (CNS). This article describes and reviews these influences, containing, for the first time, information on this subject in a single text. The ability of breath to move the brain mass and determine patterns of neural oscillation will be discussed. The role of the diaphragm in influencing motor expression and its effect on intracranial blood shifts in respiratory activity will also be discussed. It is known that the diaphragm can have multiple uses in improving the symptomatological picture of chronic diseases, but there is no current, concrete data on the effects that the rehabilitative training or manual approaches could have on the patient; in particular, on his/her cognitive and cerebral aspects in general.

Successful video-assisted thoracoscopic surgery in prone position in patients with esophageal cancer and aberrant right subclavian artery: report of three cases

Background

An aberrant right subclavian artery (ARSA) with an associated nonrecurrent right inferior laryngeal nerve (NRILN) is a relatively rare anomaly that occurs at a frequency of 0.3 to 2.0% of the general population. NRILN has been mainly documented in the head and neck region; it has been rarely described in patients with esophageal cancer, especially those undergoing thoracoscopic surgery. Video-assisted thoracoscopic surgery for esophageal cancer (VATS-E) is becoming more widespread as a reliable minimally invasive surgical procedure associated with reduced perioperative complications.

Case presentation

Herein, we report three cases of esophageal cancer with ARSA and NRILN which underwent successful VATS-E. Case 1, a 53-year-old male who had early stage esophageal cancer was performed VATS-E. Upper gastrointestinal (GI) series showed “Bayonet sign” (T1aN0M0, pStageIA in UICC). Case 2, a 75-year-old male who had advanced esophageal cancer was performed neoadjuvant chemotherapy and following VATS-E. This case had right thoracic duct and “Bayonet sign” on upper GI series (T1bN2M0, pStage IIIA in UICC). Case3, a 72-year-old male who had advanced esophageal cancer was performed neoadjuvant chemotherapy and following VATS-E (T3N2M0, pStageIIIB in UICC). All of these three cases were performed VATS-E and discharged without any complication.

Conclusion

VATS-E in the prone position is a feasible procedure that can reduce the risk of complications with an enlarged and clear view, and knowledge of this type of anomaly is very important for surgeons who perform esophagectomy.

Coexistence of Right Nonrecurrent Nerve and Bifurcated Recurrent Laryngeal Nerve Pointed by Zuckerkandl's Tubercle

The recurrent laryngeal nerve (RLN) has many anatomical variations and various relations with adjacent structures. Identification and total exposure of the cervical part of the RLN was performed during operations on the thyroid gland. An extremely rare anatomical variation of the nerve was encountered during the surgical procedure. Coexistence of both right RLN and non-RLN was observed in one patient surgically treated with total thyroidectomy. We first exposed the right RLN with an extralaryngeal terminal bifurcation at its usual position. Thereafter, we also identified an ipsilateral non-RLN joining the anterior branch of the RLN just before laryngeal entry. A Zuckerkandl's tubercle has pointed out the junction of the two nerves. In this period, the incidence of coexistence of non-RLN and RLN was 0.2% in our series. A non-recurrent course is a rare anatomical variation of the inferior laryngeal nerve. The coexistence of both non-RLN and RLN is an extremely rare anatomical finding which should be taken into account during thyroid surgery.

Neck ultrasonography for detection of non-recurrent laryngeal nerve

BACKGROUND

Non-recurrent laryngeal nerve (NRLN) is a rare anatomical variant (0.3-6%) that is associated with some arterial abnormalities (absence of the brachiocephalic trunk and presence of a right aberrant subclavian lusorian artery). The availability of a preoperative diagnosis of NRLN may reduce the risk of nerve injuries. Preoperative ultrasonography (US) has been suggested as a reliable diagnostic tool to detect the arterial abnormalities associated with NRLN, but the literature is relatively scarce. This paper was aimed to review the literature, in order to offer an up to-date on this technique and its results.

METHODS

A web search, focusing on humans, was performed by PubMed database, including papers published up to August 2016, using the key words "ultrasonography" AND "non-recurrent laryngeal nerve" or "nonrecurrent laryngeal nerve".

RESULTS

Eight papers, including 3,740 patients who underwent neck US for the detection of NRLN were selected. Only five studies focused on the preoperative use of US. The incidence of NRLN varied between 0.4% and 1.94%. The sensitivity and specificity varied between 99-100% and 41-100%, respectively.

CONCLUSIONS

US is a simple, non-invasive and cost-effective method to detect NRLN, also if its accuracy is not absolute. It may be used preoperatively and to prevent the intraoperative nerve damage, since the risk of NRLN palsies is significantly reduced when a preoperative diagnosis is available.

Nonrecurrent inferior laryngeal nerves and anatomical findings during thyroid surgery: report of three cases

A nonrecurrent inferior laryngeal nerve (NRILN) is found more frequently on the right side than on the left, and it is closely associated with an aberrant right subclavian artery. The presence of the aberrant right subclavian artery on preoperative computed tomography (CT) scan suggests NRILN; however, different types of branching locations and pathways exist. Here, we report three NRILN cases with different pathways where the vagus nerve arises more medial than usual and a review of the literature. Case 1: A 30-year-old Japanese female presented with papillary thyroid carcinoma. Preoperative CT scan revealed an aberrant right subclavian artery, and an operation was performed under suspicion of NRILN. During the operation, the vagus nerve was found to arise more medially than usual and two NRILNs originated from it at the level of the cricoid cartilage and at a more caudal position; the two NRILNs were preserved. Case 2: A 33-year-old Japanese female with a thyroid nodule of increased size underwent surgery. Preoperative CT scan revealed an aberrant right subclavian artery, which suggested NRILN. During the operation, the vagus nerve was identified to run more medially than usual and NRILN was found to originate at the level of the cricoid cartilage; NRILN was preserved. Case 3: A 78-year-old Japanese female underwent an operation with a diagnosis of papillary thyroid carcinoma. Preoperative CT scan showed an aberrant right subclavian artery. During the operation, NRILN was found to originate from the vagus nerve at the level of the lower pole of the thyroid gland, and the vagus nerve ran medial to the common carotid artery at the caudal level.

Increased and safer detection of nonrecurrent inferior laryngeal nerve after preoperative ultrasonography

OBJECTIVES/HYPOTHESIS

Right nonrecurrent inferior laryngeal nerve (NRLN) is an anatomical variant reported with a variable prevalence (0.3%-6%). It is associated with some arterial abnormalities (absence of the brachiocephalic trunk and presence of a right aberrant subclavian lusorian artery) that may be identified by preoperative ultrasonography (pUS). NRLN represents a major morbidity risk factor during neck surgery. The aim of this study was to verify pUS accuracy in predicting NRLN and to assess the impact of this technique on NRLN detection rate and laryngeal morbidity.

STUDY DESIGN

Retrospective.

METHODS

The study included 1,477 patients undergoing thyroid and parathyroid surgery with right-side inferior laryngeal nerve exploration. pUS was performed in 878 patients (pUS group); no preoperative attempts were performed in the remaining 599 patients (controls). Demographics, disease type, intraoperative inferior laryngeal nerve anatomy, and laryngeal morbidity were compared.

RESULTS

No differences occurred between the two groups concerning demographics and disease type. NRLN was detected in 17 patients (1.9%) of the pUS group and in four patients (0.6%) of controls (P < 0.05). pUS predicted NRLN in all cases, with an overall accuracy > 98%. Overall laryngeal nerves morbidity was 1.8% in the pUS group and 4.2% in the controls (P < 0.05). NRLN palsy never occurred in the pUS group, whereas it occurred three times in the controls (P < 0.005).

CONCLUSION

NRLN is accurately predicted by pUS. It occurs more frequently than expected because it may be misdiagnosed when no preoperative suspicion is available. Preoperative NRLN detection by pUS prevents inferior laryngeal nerve injuries.