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Year: 2006  Vol. 10   Num. 4  - Oct/Dec Print:
Case Report
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Non - Recurrent Inferior Laryngeal Nerve: Case Report
Nervo Larngeo Inferior No - Recorrente: Relato de Caso
Joo Alcides Miranda1, Andr Luis Sartini2, Marcello Henrique de Carvalho Borges3
Key words:
Recurrent laryngeal nerve. Thyroidectomy.

Introduction: The non-recurrent inferior laryngeal nerve is a rare anatomical variation associated with anomalies of the subclavian artery. In these cases the risk of surgical damage can be increased. Objective: Present the per-operative detection of a non-recurrent inferior laryngeal nerve and discuss the importance of its identification, when the nerve is anomaly or not, during thyroidectomies and other cervicotomies. Case Report: A 44 year-old-patient, with thyroid nodular disease, was undergone to a total thyroidectomy. During the procedure it was observed a right non-recurrent inferior laryngeal nerve. Conclusion: Only the identification of inferior laryngeal nerve, recurrent or not, can show its preservation during the thyroidectomies and others cervicotomies.


Recurrent inferior laryngeal nerve is essential when supplying intrinsic muscle of the larynx, except the cricoarytenoid one. This nerve is also responsible for supplying the larynx area which is inferior to the vocal folds. Recurrent denomination is due to its anatomical disposition, as it is a loop of the vagus nerve, going through the subclavian artery at the right side in inferior way and through the aortic arch at the left side.

For being an essential structure to laryngeal function and for its close relation with thyroid gland, the identification and preservation of the recurrent laryngeal nerve are important steps on thyroidectomy and parathyroidectomy. Its injury and then vocal fold palsy is one of the complications of these surgeries, causing dysphonia and even respiratory deficiency soon after surgery, when injury is bilateral (2,3,4). Videolaryngoestroboscopy exams can be used after surgery in order to evaluate mobility of vocal folds, confirming or not the integrity of the nerve structure (4).

Non-recurrent inferior laryngeal nerve is a rare anatomical variation associated to anatomical irregularities of the subclavian arteries. In some individuals, the right subclavian artery is retroesophageal due to embryological origin alterations, what explains the absence of recurrence of the nerve in this side.

According to many authors, its presence is estimated at 1%, and the chances of an injury is greater during surgery when involving cervical area due to either unfamiliarity from surgeon of this variation or technical difficulty to recognize and preserve the nerve in these cases (4,6,7,8).

We reported, in this study, detection of the non-recurrent inferior laryngeal nerve to the right during comprehensive thyroidectomy and discussed the need of its identification and preservation during cervicotomy, when recurrent or not.


JRB, female, 44, white, searched Servio de Otorrinolaringologia do Hospital Universitrio So Francisco - Bragana Paulista - SP (ENT Service) with a diagnosis of nontoxic multinodular goiter, according to fine needle aspiration punction (FNA) performed at another service. Patient reported sensation of cervical compression and casual dyspnea for four months.

During physical examination enlarged thyroid was touched due to node lesions of 6 x 5cm in left thyroid lobe and of 4 x 4 in right thyroid lobe. Such node injuries presented elastic fiber consistency, flat surfaces and well-defined limits. Thyroid hormones as well as anti-thyroperoxidase and anti-thyroglobulin antibodies were normal. Comprehensive thyroidectomy was recommended.

Surgery procedure went normal, therefore, during dissection for identifying right inferior laryngeal nerve it was detected that this was not recurrent, emerging straight from vagus nerve to larynx (Picture 1).

Picture 1. Right vagus nerve (VN) appears anteriorly to carotid artery and perpendicularly ejecting, i.e. with no recurrence, the inferior laryngeal nerve (ILN), which runs straight to larynx.

Surgical specimen (Picture 2) was sent to histopathological exam, and diagnosed as chronic lymphocyte thyroiditis. At the moment, patient is asymptomatic, making use of thyroid hormone and has normal exams.

Picture 2. Surgical specimen from complete thyroidectomy.


Non-recurrent inferior laryngeal nerve occurs more often to the right (0.2 to 4%) and more rarely to the left (0.07%) (4). Henry et al (8), when analyzing 3791 cervicotomies, confirmed that predominance. In this series, authors observed 17 cases of non-recurrent nerve (0.54%) in 3098 cervictomies to the right and 2 cases (0.07%) in 2846 to the left.

Subclavian artery irregularities seem to be always present, and it is the direct cause of a non-recurrent inferior laryngeal nerve. Due to embryogenic alterations, the right subclavian artery can be retro esophageal, preventing, then, that the nerve is recurrent. The same situation is not observed to the left, as recurrence occurs to aortic arch in inferior way. Only during dextrocardia we can see a non-recurrent inferior left laryngeal nerve, what explains a lower number of cases to this side (5,9).

The absence of recurrence in its course increases the chance of an injury on the inferior laryngeal nerve during thyroidectomy and other types of surgeries which achieve cervical area (6,10).

According to Sparta et al (7), only the systematic identification of the inferior laryngeal nerve assures surgeons of the absence of injury. Thus, we understand the need of an anatomic knowledge and possible variations to perform cervictomies with a lower risk of injuries to this structure.

The diagnosis of this anatomical variation is rarely performed before surgery and only a CT from thorax showing a retro esophageal subclavian artery will make us suspect of its occurrence. Detection of an anomalous nerve usually occurs during surgery and incidentally (4,10).

In this case, we observed, during surgery, a non-recurrent inferior laryngeal nerve to the right during a comprehensive thyroidectomy. Despite such difficulty, the nerve was correctly identified and preserved, as it is usual at our service.

So, we wish to aware surgeons who perform on cervical area, especially in thyroidectomies, of the importance of the inferior laryngeal nerve exposure, avoiding its incidental injury.


Inferior laryngeal nerve injury is an implication of thyroid gland and parathyroid surgeries and the risk of this occurrence enlarges when the nerve is non-recurrent. Though, only its dissection and identification assure surgeon of that such structure was totally preserved.


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2. Steffen N, Herter NT, Martha VF. Tireoidectomias. In: Campos CAH, Costa HOO. Tratado de Otorrinolaringologia Vol 5. 1 ed. So Paulo: Roca; 2003, p.557-77.

3. Gleischman S, Uyeda RY, Dunkelman D, Catz B, Karlan MS: A safe technique for thyroidectomy with complete nerve dissection and parathyroid preservation. Head Neck Surg, 1984, 6(6):1014-9.

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6. Arantes A, Gusmo S, Rubinstein F, Oliveira R: Anatomia microcirrgica do nervo larngeo recorrente: aplicaes no acesso cirrgico anterior coluna cervical. Arq Neuro- Psiquiatr,2004, 62(3):22-6.

7. Sparta C, Cossu ML, Fais E, Palermo M, Cossu F, Ruggiu M, Noya G: Non-recurrent inferior laryngeal nerve: anatomy, frequency and surgical considerations. Minerva Chir, 2004, 59(6):555-61.

8. Henry JF, Audiffrit J, Plan M: The nonrecurrent inferior laryngeal nerve: A propos of 19 cases including 2 on the left side. J Chir (Paris), 1985, 122(6-7):391-7.

9. Pisanu A, Pili S, Uccheddu A: Non-recurrent inferior laryngeal nerv. Chir Ital, 2002, 54(1):7-14.

10. Abboud B, Aouad R: Non-recurrent inferior laryngeal nerve in thyroid surgery: report of three cases and review of the literature. J Laryngol Otol, 2004, 118(2):139-42.

1. Resident Doctor at Servio de Otorrinolaringologia do Hospital Universitrio So Francisco (ENT Service).
2. Master Student at Hospital do Servidor Pblico Estadual - SP - (Assistant Doctor at Servio de Otorrinolaringologia do Hospital Universitrio So Francisco and Hospital do Servidor Pblico Estadual.
3. Resident Doctor at Servio de Otorrinolaringologia do Hospital Universitrio So Francisco.

Study done at Hospital Universitrio So Francisco - Bragana Paulista.
Joo Alcides Miranda
Address:Rua Bias Fortes, 438, Centro, Boa Esperana - MG, CEP 37170-000, phone (11) 9111-5881, e-mail jamiranda78@hotmail.com

This article was submitted to SGP - Sistema de Gesto de Publicaes (Publication Management System) from RAIO on April 7, 2006 and was approved on April 17, 2006 21:49:50.



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