Non-recurrent Laryngeal Nerve Research Articles

A case of the right non-recurrent laryngeal nerve in the thyroid cancer

The right non-recurrent laryngeal nerve (NRLN) in patients with papillary thyroid cancers is an under-reported entity. This case study is about a 26-year-old female who presented with papillary thyroid cancer. Physical examination showed involvement of the right lobe of the thyroid with no other abnormalities. Intraoperatively, with the aid of electromyography and nerve monitoring, the right non-recurrent laryngeal nerve was identified and preserved. Total thyroidectomy with inferior parathyroidectomy was done. Injury to the NRLN can lead to significant postoperative morbidity. As per meta-analysis, these nerve-related complications in minimally invasive techniques are comparable to or even less frequent than in the open approach, especially when combined with nerve monitoring and adequate training. This case report aims to raise awareness about the presence of non-recurrent laryngeal nerve in patients undergoing operative thyroid procedures and ensure its intraoperative preservation. There is also a necessity to analyse the patient to look for associated vascular anomalies.

Non-recurrent Laryngeal Nerve - A Rare Anatomical Anomaly that Increases the Risk of Nerve Injury during Thyroidectomy.

Nonrecurrent laryngeal nerve (NRLN), a rare anatomical variation of recurrent laryngeal nerve, is a branch of the vagus nerve (Morais M, Capela-Costa J, Matos-Lima L, Costa-Maia J (2015) Nonrecurrent Laryngeal Nerve and Associated Anatomical Variations: The Art of Prediction. Eur Thyroid J 4(4):234-238). On the right side, the prevalence of NRLN is 0.3-0.8%, while on the left side, it is extremely rare with a prevalence of 0.004%. A female in her twenties presented with thyroid swelling for 3 years with an ultrasound neck showing a TIRADS IV lesion in the left thyroid lobe. Contrast-enhanced tomography of the neck reported a lesion in the left thyroid lobe causing mass effect in the form of contralateral deviation of trachea and splaying of bilateral common carotid arteries from its common origin - probability of thyroid neoplasm along with aberrant right subclavian artery with a retroesophageal course was noted. Intraoperatively, the right laryngeal nerve was identified near its entry point in right cricothyroid joint and was traced laterally and was found to be nonrecurrent lying superior to inferior thyroid artery. Total thyroidectomy was done preserving the left recurrent laryngeal nerve and right non recurrent laryngeal nerve. NRLN should be suspected in cases with vascular anomalies based on preoperative imaging. Meticulous dissection during thyroid surgery for identification of the recurrent laryngeal nerve or NRLN is still considered to be the precise approach to avoid nerve injury.

Non-recurrent Laryngeal Nerve and Variant Thoracic Duct Anatomy in the Presence of an Aberrant Right Subclavian Artery During Esophageal Cancer Surgery

Non-recurrent Laryngeal Nerve and Variant Thoracic Duct Anatomy in the Presence of an Aberrant Right Subclavian Artery During Esophageal Cancer Surgery

Non recurrent laryngeal nerve: be vigilant

The nonrecurrent laryngeal nerve (NRLN) is a rare variant of the RLN, which results from the partial failure of pharyngeal apparatus during embryological development. It’s a rare anatomical variation in which the nerve doesn’t descend to the thorax and enters the larynx directly from the vagus nerve in the neck. It’s an uncommon anatomical variation usually associated with subclavian artery abnormalities, so identification of these vascular anomalies before the surgery is important to avoid nerve injury. These anomalies lead to difficulty in finding the RLN and hence the chances of injury to the nerve are more. Lack of knowledge about the course of RLN, its anatomical variations and its relationship to the vital structures poses the risk of iatrogenic damage of the nerve. Most of the cases of NRLN are diagnosed intraoperatively, as there is no specific test for this. So, surgeons should always be vigilant about the NRLN during thyroid and parathyroid surgeries.

AB128. SOH24AB_056. The non-recurrent laryngeal nerve in an Irish thyroid surgery population: an 11-year experience

AB128. SOH24AB_056. The non-recurrent laryngeal nerve in an Irish thyroid surgery population: an 11-year experience

Presentation of Arteria Lusoria with Non Recurent Laryngeal Nerve.

Non-recurrent laryngeal nerve (NRLN) is an anatomic variation seen in about 0.52-0.7% patients, generally on right side. It exits the vagus nerve having a direct route to the larynx, unlike usual recurrent laryngeal nerve, supplying intrinsic laryngeal muscles except cricothyroid. It is sited over left side on extremely rare occasions, that is, 0.04% of the cases. Some cases of NRLN co-exists with aberrant right subclavian artery which courses behind the esophagus, also known as 'arteria lusoria'. Here we present a case of 60-years old patient, diagnosed as goiter presented to us in june 2023 at the department of head and neck surgery at a tertiary care setup of Karachi Pakistan. Intra-operatively, non-recurrent nerve was encountered, whose association was found with arteria lusoria, observed in pre-operative CT-scan. The nerve was saved and no post-operative complications were seen in patient. The association of arteria lusoria in this case emphasize its importance in predicting NRLN via pre-operative imaging techniques which can prevent its injury intra-operatively.

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 environmentwhere 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.

Continuous Intraoperative Nerve Monitoring of a Non-Recurrent Laryngeal Nerve: Real-Life Data of a High-Volume Thyroid Surgery Center.

Thyroid surgery is associated with a risk of injury to the recurrent laryngeal nerve, especially in the presence of anatomical variants such as a non-recurrent laryngeal nerve (NRLN). Injury to the nerve leads to transient or permanent vocal cord palsy (VCP). A novel method to prevent VCP is continuous intraoperative nerve monitoring (cIONM), but less is known about the applicability of this method in patients with NRLN. The aim of this study was to evaluate our own data regarding feasibility and detailed characteristics of cIONM in NRLN patients. We performed a monocentric retrospective cohort analysis including clinical data and intraoperative nerve monitoring data (measured by Inomed Medizintechnik GmbH, Emmendingen, 'C2' and 'C2 Xplore' device) of all thyroid surgery patients, showing NRLN between 2014 and 2022. Of 1406 patients who underwent thyroid surgery with cIONM between 2014 and 2022, 12 patients (0.9%) showed NRLN intraoperatively. Notably, cIONM was feasible in eight patients (67%). In all cases the onset latency of the right vagus nerve was shorter (<3.0 ms) than usually expected, suggesting that a short latency might be suitable to distinguish NRLN. None of the patients had a post-operative VCP. Overall, cIONM appears to be feasible and safe in NRLN patients and provides helpful information to prevent VCP.

Non-recurrent laryngeal nerve: An anatomical variation in thyroid surgery

Non-recurrent laryngeal nerve is a rare anomaly which makes it prone to iatrogenic injury during thyroid surgeries. The aim of this article is to show the presence of non-recurrent laryngeal nerve in a patient being operated for thyroidectomy.

Non-recurrent Laryngeal Nerve During Intraoperative Neuromonitoring Thyroidectomy: A Case Report and Literature Review.

Complete and precise knowledge of the neck anatomy and its eventual anomalies is crucial while performing a safe thyroid and parathyroid surgery. Embryo-genetic malformations of the IV branchial arch can lead to an uncommon anatomical alteration known as non-recurrent inferior laryngeal nerve. Its prevalence varies between 0.7% for the dextral branch and 0.04% for the sinistral. In these cases, the inferior laryngeal nerve branches originate directly from the cervical vagus nerve, entering the larynx without hooking, on the right side around the subclavian artery or on the left around the aortic arch. The presence of a non-recurrent laryngeal nerve is challenging, due to the increased risks of iatrogenic damage to the nerve, which results in hoarseness, dysphagia, glottal obstruction, vocal cords palsy, and serious airway impairment. We present the case of a 58-year-old woman. The patient was admitted to our department for a nodule classified as Bethesda IV in the right thyroid lobe. Through the use of intraoperative neuromonitoring (IONM), surgeons detected intraoperatively a non-recurrent laryngeal nerve. A subsequent computed tomography scan confirmed an anomalous right subclavian artery branching from the left aortic arch, the Lusoria Artery. Anatomical variants represent pitfalls in this case and an accurate knowledge of the neck region is imperative while performing thyroid surgery. Devices such as IONM are useful for detecting abnormalities that may lead to iatrogenic damages.

Anatomical relations of the recurrent laryngeal nerve in thyroid dissection

Introduction: Recurrent laryngeal nerve (RLN) palsy is one of the major complications thyroidectomy. Visualization of the anatomical relations of the RLN with branches of the inferior thyroid artery (ITA) remains essential for preservation of RLNs. Suspensory ligament of Berry, inferior horn of the thyroid cartilage is considered as other important landmarks for safe thyroidectomy. The objective of this study was to describe the various anatomical relations of the RLN during thyroid dissection.Methods: An observation cadaveric study was conducted by simple random sampling of 35 cadavers with a total of 70 RLNs over a one-year period, from June 2022 to June 2023. The cadavers that had thyroidotomies and goitres were excluded from the study.Results: The majority of RLNs in this series had a retrovascular course (with respect to the ITA or its branches): 57% on the right and 68.6% on the left. The course of 64/70 of the dissected nerves was posteromedial to the suspensory ligament of Berry, while the other 6 nerves passed between the fibres of this ligament. All RLNs penetrated the larynx by passing posteriorly to the inferior horn of the thyroid cartilage on both sides. No case of non-recurrent laryngeal nerve was observed.Conclusion: This preliminary study illustrates the numerous anatomical variants of the RLN with respect to the ITA and its branches. The RLN mainly has a retrovascular course on both the right and the left sides.

Comprehensive review of laryngeal nerve

The laryngeal nerve plays a crucial role in vital functions of the larynx, such as breathing, phonation, and airway protection. This review explores its intricate origination, extracranial pathways, anatomical variations, and functions. Emerging from the vagus nerve, it descends through the jugular foramen, exhibiting distinct pathways on each side of the body. Understanding these pathways is vital in surgery to prevent complications. Anatomical variations, including the non-recurrent laryngeal nerve and extralaryngeal branching, pose challenges during thyroid surgery. Surgeons must be vigilant, as failure to recognize these variations can lead to nerve injuries. Meticulous preoperative evaluation and surgical expertise are essential. The superior laryngeal nerve triggers protective reflexes like the cough reflex, safeguarding the respiratory tract. The recurrent laryngeal nerve controls crucial laryngeal muscles for phonation and respiration. Understanding these functions is paramount, especially for surgeons, ensuring optimal patient outcomes. In conclusion, this review underscores the laryngeal nerve's complexity and the need for in-depth knowledge, particularly in surgery. Ongoing research and medical advancements are crucial for refining techniques and enhancing patient care. Acknowledging these complexities empowers medical surgeons contributing to safer and more effective surgeries.

Dysphagia Revealing an Aberrant Subclavian Artery or Arteria Lusoria: A Case Report

Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are among the commonest aortic arch anomalies, by passing behind the esophagus, it can cause a condition known as lusoric dysphagia, responsible for symptoms of discomfort. This artery is often associated with other anomalies, such as the non-recurrent laryngeal nerve, the bicarotid trunk, and with diseases such as aneurysms, congenital heart defects and even genetic syndromes. Here we report a case of an 82-year-old women patient has been referred to our department for an angio scanner of the supra-aortic trunk for etiological assessment of chronic dysphagia. Which has revealed an aberrant right subclavian artery (Arteria lusoria) associated with a bicarotid trunk.

Non-recurrent laryngeal nerve in thyroid and parathyroid surgery

BACKGROUND: the main reason for postoperative vocal folds paresis is the variable anatomy of the recurrent laryngeal nerve. An example of such an “extreme form of embryonal development» is the non-recurrent laryngeal nerve. However, many surgeons consider this structure to be a rare anomaly with prevalence less than 0.5%. This opinion is associated with a six to seven-fold increase in the number of vocal folds paresis when a surgeon encounters with a non-recurrent laryngeal nerve. Meanwhile, in cadaveric studies a significantly higher prevalence of non-recurrent laryngeal nerve was demonstrated — 2.2%. The right aberrant subclavian artery was diagnosed during CT in 3.1% patients.AIM: the aim of the study is to determine the effectiveness of preoperative ultrasound in detecting the right aberrant subclavian artery and non-recurrent laryngeal nerve.MATERIALS AND METHODS: patients underwent thyroid and parathyroid surgery with identification of a right inferior laryngeal nerve. The preoperative neck ultrasound was performed on all patients with visualization of a brachiocephalic trunk (Y-sign) or a right aberrant subclavian artery (AL-sign). CT-angiography was performed in the postoperative period on patients who had a non-recurrent laryngeal nerve.RESULTS: the study included 1476 patients. The Y-sign was determined among 1338 (90.7%) patients. In these cases a typical anatomy of the recurrent laryngeal nerve was observed. In 138 (9.3%) cases, the Y-sign was not detected. In this subgroup of patients, in 20 (1.4%) cases, a non-recurrent laryngeal nerve and a right aberrant subclavian artery were noted. Thus, the sensitivity of the Y-sign in confirming the normal anatomy of the recurrent laryngeal nerve was 100%, specificity — 91.9%, positive prognostic value — 14.5%, negative prognostic value — 100%. On the contrary, AL-sign was notedall 20 (1.4%) patients with non-recurrent laryngeal nerve and right aberrant subclavian artery. False positive and false negative results were not observed. Three variants of the non-recurrent laryngeal nerve were identified: type I (superior type) — located behind the upper third of the thyroid lobe, has a direct descending way and forms an angle to the larynx of 30–50°; type III (inferior type) — has a direct ascending way (simulates the course of the recurrent laryngeal nerve) and forms an angle to trachea in 30–50°; type II (middle type) — all variants of the non-recurrent laryngeal nerve located between types I and III.CONCLUSION: the preoperative ultrasound detection of brachiocephalic trunk (Y-sign) confirms the presence of a recurrent laryngeal nerve (sensitivity 100%), and visualization of the right aberrant subclavian artery (AL-sign) determines a non-recurrent laryngeal nerve (sensitivity and specificity 100%).

Variant anatomy of non-recurrent laryngeal nerve: when and how should it be taught in surgical residency?

While the performance of a thyroidectomy is generally associated with a low risk of injury to the recurrent laryngeal nerve (RLN), the presence of a non-recurrent nerve (NRLN) increases the risk of this complication. Generally, the intraoperative detection via visual appreciation of variant anatomy of the RLN has been regarded as poor, possibly due to a lack of knowledge of both the normal and aberrant anatomy of the RLN. Articles for the review were searched through PubMed using the search terms and their combinations: "non-recurrent laryngeal nerve," "thyroidectomy," "injury," "palsy," "variant anatomy," and "residency," from January 1, 2000, to December 2022. Papers considered for the review were the articles published in English, with additional classic and articles of surgical importance retrieved from the reference list of papers. Only papers relevant to the scope of the review were considered for this review. The NRLN has been found to be associated with concurrent vascular abnormalities, such as the presence of an aberrant right subclavian artery (ARSA) or an arteria lusoria originating from the aortic arch. However, it seems that both the normal as well as aberrant anatomy of the RLN is currently not emphasized enough during postgraduate surgical training. With the increased use of intraoperative neuromonitoring (IONM), detection of NRLN has become possible through appropriate neural mapping during thyroid surgery, besides other pointers such as visualization during surgery, computerised tomography, and duplex ultrasound scans to visualize the variant vascular anatomy. There is also a possible role for cadaveric courses, either during medical school or in a post-graduate setting-adapted to the student's level to teach the variant anatomy. With the development of newer techniques such as artificial intelligence, there are potential new options for teaching and training anatomy in the near future. Adequate knowledge of the normal and aberrant anatomy of the RLN remains essential for the best outcomes in thyroid surgery, even in the era of the IONM. Moving forward, the knowledge of (aberrant) anatomy should be made an integral part of the core competencies of both medical students and surgical trainees. It is imperative that leaders of the different field work closely together to combine their knowledge towards providing their trainees with the best possible training options.

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

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. 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. 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. 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.

Nonrecurrent Laryngeal Nerve

The nonrecurrent laryngeal nerve (NRLN) is a rare anatomical variation of the recurrent laryngeal nerve (RLN), in which the nerve enters the larynx directly from the cervical vagus nerve without descending to the thoracic cavity. Knowledge of the anatomy of the RLN and its variations, as well as its identification and careful dissection, is essential to avoid injury to the nerve during thyroid surgery. If not predicted intraoperatively, this anatomical variation can put the nerve at risk with subsequent vocal fold palsy. We report this rare case to highlight the importance of anatomical knowledge to identify NRLN during thyroid and parathyroid surgery.

Artéria subclávia direita aberrante: relato de caso e revisão de literatura

The aberrant right subclavian artery, also known as the arteria lusoria, is the most common aortic arch anomaly, occurring in 0.5 to 1% of the population. There is a higher prevalence in women and it is usually associated with other anatomical variations, such as the non-recurrent laryngeal nerve, present in 86.7% of cases. In the majority of cases, the aberrant right subclavian artery causes no symptoms. We describe this anomaly in an 82-year-old, hypertensive, and asymptomatic patient who had undergone a thoracoabdominal angiography to investigate a chronic DeBakey type III aortic dissection with dilation of the descending aorta. The aberrant right subclavian artery followed a retroesophageal course and was associated with a Kommerell diverticulum. In view of its rarity, we conducted an integrative bibliographic review of literature from the last 6 years indexed on the Medline, UpToDate, Lilacs, Scielo, and Portal Capes databases and discuss the most frequent anatomical changes, symptomatology, and therapeutic management adopted.

Concurrent Ipsilateral Recurrent and Nonrecurrent Laryngeal Nerve During Thyroidectomy: A Case Report

Concurrent Ipsilateral Recurrent and Nonrecurrent Laryngeal Nerve During Thyroidectomy: A Case Report

Non-Recurrent Laryngeal Nerve (NRLN): A rare anatomical anomaly of the recurrent laryngeal nerve

A 34-year young lady with a right-sided euthyroid nodule of 3x5 cm size for one year visited our clinic for surgery. FNAC was reported as colloid goiter. The right hemi-thyroidectomy surgery was planned. Intraoperatively while dissecting the right thyroid lobe, we could not find the right recurrent laryngeal nerve in its normal course, but we found a cord white-like structure running transversely &amp; entering the larynx at the level of the cricothyroid muscle. We dissected it till its origin from the right vagus nerve in the neck. So, this was Non-recurrent laryngeal nerve (NRLN) which is a rare anatomical anomaly of the Recurrent Laryngeal Nerve (RLN) which arises higher in the neck and runs a course directly to the larynx as the NRLN without looping around the vessels in the chest. This intraoperative image is showing right-sided neck structures after removal of the right thyroid lobe &amp; isthmus. The labeled structures in the image from right to left are the common carotid artery (CCA), Vagus Nerve (VN), Non-recurrent laryngeal nerve (NRLN), trachea &amp; left lobe of the thyroid gland. Her post-operative recovery was good without any voice change. The final histopathology report was suggestive of colloid goitre.