Cases Of Non-recurrent Laryngeal Nerve Research Articles

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.

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.

Nonrecurrent laryngeal nerve-an anatomical deviation

<p>Thyroidectomy is one of the most dispute and discussed surgery. Identification of recurrent laryngeal nerve is the most important step in this surgery. Among postop complications of thyroidectomy, the commoner is haematoma, transient hypocalcaemia and hoarseness.<strong> </strong>We report a rare case of nonrecurrent laryngeal nerve in a 25-year-old male with swelling in the right thyroid lobe. A 25-year-old male presented to the ENT OPD with complaints of swelling in thyroid region for 6 months with no other symptoms. On examination there was a 2×3 cm size nodule in the right lobe of thyroid. Rest of ORL examination was normal. On ultrasonogram there was an enlarged right lobe of thyroid with a nodular goitre. Fine needle aspiration cytology showed colloid goitre. Patient was planned for right hemithyroidectomy. Right side type 1 nonrecurrent laryngeal nerve was identified at the level of superior pole of thyroid branching from vagus and entering the larynx at the level of cricothyroid joint was identified intraoperatively.<strong> </strong>In conclusion, nonrecurrent laryngeal nerve though a very rare anomaly forms a crucial anatomical structure in thyroid surgery and is prone to injury. It is one of the preventable complications during thyroid surgery leading to postop vocal cord palsy. An in-depth anatomical knowledge and diligent surgical technique will help in identification and preservation of nonrecurrent laryngeal nerve.</p>

ЗАКОНОМЕРНОСТИ АНАТОМИИ И ТОПОГРАФИИ ГОРТАННЫХ НЕРВОВ У ВЗРОСЛОГО ЧЕЛОВЕКА ПО ДАННЫМ ЛИТЕРАТУРЫ

Establishing the morphological regularities of laryngeal nerves of the human is extremely important in surgical and oncological practice. During surgical intervenrions on the thyroid gland, damage of the superior and inferior laryngeal nerves can occur — the second most common complication after hypoparathyroidism. Based on the studied literature data on anatomy and topography of the laryngeal nerves in an adult, a number of the morphological features have been identified. The article describes the morphometric parameters of the laryngeal nerves and their branches. Also, the article describes variants of the localisation of the internal branch of the superior laryngeal nerve relatively to the superior laryngeal artery, a number of classifications based on the localisation of the external branch of the superior laryngeal nerve relatively to the superior thyroid artery and the inferior laryngeal constrictor, variants for the inferior laryngeal nerve passage in tracheoesophageal groove, its location in relation to the trunk and branches of the inferior thyroid artery, Berry's ligament, Zuckerkandl's tubercle and also such anatomical features of the inferior laryngeal nerve as its extralaryngeal branching and cases of non-recurrent laryngeal nerve. These topographic and anatomical features of the laryngeal nerves that should be taken into account for the identification of the nerves during surgery, and also allows them to be considered prerequisites for an increased risk of iatrogenic trauma.

English

Both the cases discussed here had right sided NRLN, out of which one had associated aberrant right subclavian artery. None had iatrogenic nerve palsy. Dissection was difficult as during the routine procedure of dissection, the nerve was not found in its usual route and was found that the right laryngeal nerve was not recurrent and originated directly from the vagus nerve. The non-recurrent laryngeal nerve (NRLN) is a rare embryologically derived variant of the recurrent laryngeal nerve and is found in 0.25 to 0.99% of patients who undergo thyroid surgery. On the right side, NRLN is found in 0.3% to 0.8% of patients and it is extremely rare on the left (0.004%).[1-2] The right NRLN is found to be associated with an aberrant right subclavian artery (86.7%) In experienced hands, meticulous dissection in the region of the tracheoesophageal groove will result in identification of RLN. In any case, if the nerve is not seen / found longitudinally along the tracheoesophageal groove, then dissecting transversely along the fascial spaces between the carotid sheath and the larynx, will allow identification of the presence of NRLN. Recurrent laryngeal nerve is a branch of the vagus nerve that is associated with both motor function and sensation of the larynx. It supplies all the intrinsic muscles of the larynx except the cricothyroid muscles. The non-recurrent laryngeal nerve (NRLN) is a rare embryologically derived variant of the recurrent laryngeal nerve and occurs in 0.25 to 0.99% of patients who undergo thyroid surgery and was first reported by Steadman in 1823.[3] on the right side, NRLN is found in 0.3% to 0.8% of patients and on the left side, it is extremely rare (0.004%).[1-2] The right NRLN is found to be associated with an aberrant right subclavian artery (86.7%).[1],[4] The NRLN is usually an unexpected surgical discovery, specifically during thyroidectomy. Hence, adequate anatomic knowledge of the normal course and variations/types of NRLN, and careful dissection during surgery is necessary to prevent iatrogenic injury to the nerve. We are reporting two cases of NRLN, which were identified while performing total thyroidectomy in patients diagnosed with papillary ca thyroid.

Utility of intraoperative neuromonitoring in detecting recurrent nerve's anatomical anomalies during thyroidectomy.

Anatomical variations such as a non-recurrent laryngeal nerve (NRLN) are very rare (reported rates within 0.6-1% to the right side and only four cases to the left side) but they can lead to serious risk of nerve lesion during thyroidectomy. It is known that to prevent inferior laryngeal nerve lesions, it is mandatory to obtain a correct and wide exposure of the nerve during all kind of thyroid surgeries but in case of laryngeal nerve position anomalies, it is hard to achieve a safe nerve identification. Continuous intraoperative neuromonitoring (C-IONM) technology can detect the presence of NRLN. In this study we present seven cases of NRLN incidentally found during our last 10-year experience, in a total of 1074 procedures, including total thyroidectomy and lobectomy. Three out of seven cases were identified with the help of C-IONM. On the other hand, the other four cases of non-recurrent laryngeal nerve were identified during an extensive dissection of the thyroid lodge. We registered no nerve palsy in the group of patients who underwent surgery with the help of C-IONM, while we had two nerve palsies (out of four cases) in the group of patients without the help of C-IONM. In our experience we also registered a reduction of surgery time when we used the C-IONM. In our opinion C-IONM is a safe method to discover anatomical anomalies such as a non-recurrent laryngeal nerve and may help to reduce nerve palsy rate.

Preoperative computed tomography diagnosis of non-recurrent laryngeal nerve in patients with esophageal carcinoma.

BackgroundThe non‐recurrent laryngeal nerve (NRLN) is a rare but potentially serious anomaly that is commonly associated with the aberrant right subclavian artery (ARSA). It is easy to damage during surgical resection of esophageal cancer, leading to severe complications.MethodsPreoperative enhanced thoracic computed tomography (CT) scans of 2697 patients with esophageal carcinoma treated in our hospital between January 2010 and December 2013 were examined. We classified the positional relationship between the right subclavian artery and the membranous wall of the trachea into two types and used this method to predicate NRLN by identifying ARSA.ResultsTwenty‐six patients (0.96%) were identified with ARSA, all of which were cases of NRLN by CT. NRLN was identified during surgery in the 26 patients, and a normal right recurrent laryngeal nerve was observed in 2671 patients. The ARSA was detected on the dorsal side of the membranous wall of the trachea in all 26 NRLN cases, while it was detected on the ventral side in all 2671 recurrent laryngeal nerve cases.ConclusionEnhanced CT scanning is a reliable method for predicting NRLN by identifying ARSA. Preoperative recognition of this nerve anomaly allows surgeons to avoid damaging the nerve and abnormal vessels during esophagectomy.

Retroesophageal Right Subclavian Artery with Nonrecurrent Laryngeal Nerve: Unique Variation of Surgical Importance

ABSTRACT A nonrecurrent laryngeal nerve (NRLN) is a rare anatomical variant and is not detected on routine preoperative imaging. NRLN is related with absence of the brachiocephalic trunk and aberrant retroesophageal course of the right subclavian artery (arteria lusoria) which is evident on contrast-enhanced computerized tomographic (CT) scan of the chest. We report three cases of NRLN accidentally documented during total thyroidectomies for papillary carcinoma of the thyroid. All the three NRLNs seen on the right side were of the type IB variety. All the three NRLN were seen with its direct branch from the vagus at the level of the isthmus entering the cricothyroid muscle 2.5 to 3 cm away from the vagus without a recurrent course. Reviewing of contrast-enhanced CT scan of the chest revealed retroesophageal right subclavian artery (arteria lusoria) a variation of type I variety was evident in all the three cases. NRLN is a rare anatomical variant and routine preoperative imaging studies are not indicated. The risk of injury to the nerve is nullified by routine dissection and identifying its course along the paratracheal region. NRLN is related with absence of the brachiocephalic trunk and aberrant (mainly retroesophageal) course of the right subclavian artery which is evident on contrast-enhanced CT scan of the chest. Expensive imaging modalities are not warranted to screen a variation which is less than 1%. How to cite this article Shenoy AM, Nanjundappa A, Halkud R, Chavan P, Gupta S, Naidu K, Naik SM. Retroesophageal Right Subclavian Artery with Nonrecurrent Laryngeal Nerve: Unique Variation of Surgical Importance. World J Endoc Surg 2013;5(2): 33-38.

A CASE OF NON-RECURRENT LARYNGEAL NERVE

A case of non-recurrent laryngeal nerve is presented. A 63-year-old woman was admitted to the hospital because of a thyroid cancer. At the operation, the left recurrent nerve was seen in the usual position. But the right recurrent nerve was not present in the right tracheoesophageal groove. The right non-recurrent laryngeal nerve was arising from the cervical trunk of the vagus, and passing transversely into the right side of trachea. A post operative angiogram showed an abnormal right subclavian artery which directly arised from the distal part of aortic arch. She had no trachyphonia, dyspnea nor dysphagia. The right recurrent laryngeal nerve is embryologically related to the fourth arch vessel which becomes the right subclavian artery. Rarely, when the fourth vessel disappears, this nerve is not arrested by this vessel and arises directly from the vagus. Consequently, the right subclavian artery arises from the distal aorta, just distal to the left subclavian artery, and crosses to the right behind the trachea and esophagus. So, it can be associated with dysphagia. This type of anomaly is rare, but surgeons should know the presence of the non-recurrent laryngeal nerve for thyroidectomy. It is also necessary to follow the occurrence of dyspnea and dysphagia.

Non-Recurrent Laryngeal Nerve: Identification during Thyroid Surgery

The non-recurrent course of the inferior laryngeal nerve is a rare anomaly. The incidence varies from 0.3 to 4% on the right side. It is extremely rare on the left side. The awareness of such an anomaly is essential as the risk of damage to the nerve is higher during thyroid surgery. Two cases of non-recurrent laryngeal nerve are reported, and the embryology and method of identification are discussed.