Non-recurrent Laryngeal Nerve Research Articles

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.

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: A rare anatomical variation – A case report and literature review

Nonrecurrent laryngeal nerve: A rare anatomical variation – A case report and literature review

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.

Non-Recurrent Laryngeal Nerve (NRLN) is a rare anatomical anomaly of the RLN

A 34-year young lady with a right-sided euthyroid nodule of 3 x 5 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

Abu Dhabi Neural Mapping (ADNM) during Minimally Invasive Thyroidectomy Enables the Early Identification of Non-Recurrent Laryngeal Nerve and Prevents Voice Dysfunction.

The aim of this study was to evaluate the diagnostic accuracy of a neuromonitoring protocol—the Abu Dhabi Neural Mapping protocol (ADNM)—using a new device, Nim-Vital™, during minimally invasive thyroidectomy in the early identification of non-recurrent laryngeal nerve (n-RLN) problems and the preservation of its function. Method: Patients with thyroid disorders that required thyroid resection, who were admitted to the Department of Surgery at Burjeel Hospital, Abu Dhabi, between January and July 2022, were included in the study. The data were extracted from a prospective database and were analyzed retrospectively. All nerves at risk were identified and exposed at seven precisely defined anatomical points, with strict adherence to the intraoperative technical steps of neuromonitoring. These were sequentially applied to the vagal nerve (VN), the superior laryngeal nerve (SLN), and the recurrent laryngeal nerve (RLN). In the next step after the creation of the skin-platysma flap, the strap muscle’s lateral border was moved from the medial limb of the sternocleidomastoid without using any electrical device and without any manipulation of the thyroid gland. The VN was exposed in the carotid sheath and then stimulated using a monopolar probe at a precisely defined point above the clavicle, using anatomical landmarks. Results: In total, 136 women with a mean age of 40 years (range 18–74) and 36 men with a mean age of 42 (range 21–66), demonstrating 270 nerves at risk, were included in the analysis. Indications for surgery were malignancy in 70 cases, toxic goiter/Graves in 23 cases, retrosternal goiter in 21, and symptomatic multinodular goiter in 64 cases. Of these, 100 patients received a total thyroidectomy, 46 received a right lobectomy, and 24 received a left lobectomy only. For a total thyroidectomy, the median skin-to-skin surgery duration was 52 min (range 24–104 min) and the median hospital stay was 2 days (range 1–4 days). In 4 cases (4/146; 2.74%) the pre-dissection stimulation of the vagal nerve (VN1) at the ADNM’s precisely defined point did not create any signal or proper EMG-curve that indicated the existence of the non-RLN. Proximal dissection of the right VN at a precisely defined point by the ADNM’s level of incisura of the larynx created a positive signal. The separation point of the right non-RLN from the VN was discovered in all four patients. The postoperative video-laryngoscopy confirmed bilateral mobile vocal cords in all cases. Conclusions: Following the ADNM protocol during thyroid surgery minimizes the risk of a non-laryngeal nerve injury and prevents voice dysfunction.

Intra-operative discovery of nonrecurrent inferior laryngeal nerve: a report of 3 cases including one of left nonrecurrent inferior laryngeal nerve and literature review

&lt;p&gt;The nonrecurrent inferior laryngeal nerve (NRILN), a rare variant in the course of the inferior laryngeal nerve, passes transversely into larynx directly arising from the vagus nerve that increases the risk of damage to the nerve during thyroid and parathyroid surgery. We discussed clinical significance of non-recurrent laryngeal nerve during cervicotomy. Its importance was demonstrated in three clinical cases as well as the related literature reviews. All patients underwent bilateral thyroidectomy for a multinodular goiter. Two patients had identification of the NRILN on the right side. The third patient had the NRILN on the left side. The diagnosis of this anatomical variation was made per-operatively on all cases. The NRILN is an exceptional anomaly but overlooking its risk may lead to grave morbidity. This is a supplementary proof in favour of systematic dissection of the recurrent inferior laryngeal nerve (RILN) during all thyroid and parathyroid surgery.&lt;/p&gt;

A Case Report of Non-Recurrent Laryngeal Nerve

The non-recurrent laryngeal nerve is a rare neurological disorder associated with the underdeveloped subclavian artery. During thyroidectomy, this abnormal nerve can be inadvertently damaged, causing permanent vocal cord paralysis. However, preoperative diagnosis of the abnormal subclavian artery can predict the presence of non-relapsed laryngeal nerve. We report a case of right recurrent laryngeal nerve-related thyroid surgery that was not noticed preoperatively on a CT scan of the neck but was accidentally encountered during thyroidectomy. Preoperative CT scan showed an abnormal right subclavian artery in the posterior esophagus, but was unnoticed. A female patient underwent total thyroidectomy with central compartment node autopsy for thyroid cancer. The recurrent laryngeal nerve on the left side was identified, as well as the non-relapsed laryngeal nerve on the right side. Postoperatively, the patient had normal vocal cord function. By identifying the abnormal right recurrent laryngeal nerve with a CT scan of the neck, it is possible to predict the right recurrent laryngeal nerve preoperatively, which may help prevent vocal cord paralysis.

An atypical bilateral trifurcation of recurrent laryngeal nerve

BackgroundThyroidectomy is a frequently performed surgery for benign and malignant conditions. Nevertheless, one of the most critical complications of thyroidectomy is recurrent laryngeal nerve (RLN) injury leading to vocal cord paralysis. A thorough knowledge of the anatomical variations of RLN and ligation of the related vessels close to their distal branches is critical to avoid injury.Case presentationHere, we report the first case of bilateral trifurcation of recurrent laryngeal nerve (RLN) in a 40-year old woman with multinodular goitre. Total thyroidectomy was performed and RLN was preserved bilaterally. Followed by a precise dissection, fine branches were traced penetrating the larynx. We did not observe any further post-operative complications and patient was discharged with desired outcomes.ConclusionsAnatomical variations of the RLN include—bifurcations, trifurcations, relation of RLN with inferior thyroid artery (ITA) and presence of non-recurrent laryngeal nerve. Only RLN dividing at a distance greater than 5 mm (branching point distance) before its entry into the larynx beneath the cricothyroid are said to bifurcate or trifurcate. Approximately 25% of nerves show branching [71%—unilateral and 18%—bilateral bifurcation]. Incidence of unilateral trifurcations have been noted be 0.9% and the rates of bilateral trifurcation and the divisions of the branches is yet to be ascertained. This is the first report of a bilateral trifurcation of RLN, detected in patient with multinodular goitre and hence warrants a precise analysis of variations of the RLN in patients undergoing thyroidectomy, which is critical to prevent RLN injury.

Semi-prone thoracoscopic esophagectomy for esophageal carcinoma with aberrant right subclavian artery and non-recurrent inferior laryngeal nerve

BackgroundAberrant right subclavian artery (ARSA) accompanied by non-recurrent inferior laryngeal nerve (NRILN) is a rare anomaly. In cases of thoracic esophageal carcinoma associated with ARSA and NRILN, surgeons must take extra care not to injury these vessels and nerves. We believe semi-prone thoracoscopic esophagectomy to be a surgical approach that can safely deal with such an anomaly.Case presentationA 70-year-old man complained of feelings of chest constriction. Endoscopic examination revealed an esophageal tumor and computed tomography showed an ARSA. We performed semi-prone thoracoscopic esophagectomy for case with ARSA and NRILN. We identified these anomalies during esophagectomy, and we could complete surgery without injury these vessels and nerves. The patient had an uneventful recovery and discharged 22 days after surgery.ConclusionsSemi-prone thoracoscopic esophagectomy for esophageal carcinoma can be performed safely with a wide operative field, and is an excellent procedure for dissecting esophageal carcinoma in patients with ARSA and NRILN.

The Nonrecurrent Laryngeal Nerve: Anatomic and Embryologic Considerations, Imaging Findings, and Intraoperative Testing

The Nonrecurrent Laryngeal Nerve: Anatomic and Embryologic Considerations, Imaging Findings, and Intraoperative Testing

Surgical video on the successful preservation of the non-recurrent laryngeal nerve and the importance of preoperative CT imaging during total thyroidectomy: case report

Surgical video on the successful preservation of the non-recurrent laryngeal nerve and the importance of preoperative CT imaging during total thyroidectomy: case report

Left Nonrecurrent Laryngeal Nerve with Situs Inversus Totalis.

The recurrent laryngeal nerve (RLN), a branch of the vagus nerve, supplies the motor and sensation function of the larynx. Generally, RLN detours around the right subclavian artery on the right side and the aortic arch on the left side. In a rare anatomical variant, called nonrecurrent laryngeal nerve (NRLN), the nerve takes an aberrant path rather than descending into the thorax as usual. First reported in 1823, NRLN is a rare anomaly arising almost exclusively on the right side, reported in 0.3–0.8% of people, and associated with vascular anomalies of embryonic aortic arch development. The atypical vascular pattern of aberrant subclavian artery (arteria lusoria) running behind the trachea and esophagus allows the vagus nerve to pass freely, which then directly branches out as NRLN at the level of the larynx. On the other hand, cases of left NRLN, only reported in 0.004% of people, are all accompanied by significant pathologies such as situs inversus totalis with opposite vascular pattern of left aberrant subclavian artery. This rare anatomical variation is clinically important, as NLRN is a major risk factor for iatrogenic injury during thyroidectomy, parathyroidectomy, and other invasive procedures in the head and neck region.