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Year : 2012  |  Volume : 9  |  Issue : 2  |  Page : 56-57

Expect the unexpected: Nonrecurrent laryngeal nerve

1 Department of ENT, K S Hegde Medical Academy, Mangalore, Karnataka, India
2 Department of Surgery, K S Hegde Medical Academy, Mangalore, Karnataka, India

Date of Web Publication12-May-2012

Correspondence Address:
Vinay Vaidyanathan
Department of ENT, K S Hegde Medical Academy, Mangalore, Karnataka-575 018
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-0354.96050

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Injury to recurrent laryngeal nerve (RLN) in thyroid surgeries is the single most high morbid complication making thyroid surgery challenging. Presence of nonrecurrent laryngeal nerve (nRLN) increases the risk of injury many folds. Sound anatomical knowledge of this variant course can help the surgeon avert disaster.

Keywords: Nonrecurrent laryngeal nerve, recurrent laryngeal nerve

How to cite this article:
Vaidyanathan V, D'Souza C, Shetty K. Expect the unexpected: Nonrecurrent laryngeal nerve. Thyroid Res Pract 2012;9:56-7

How to cite this URL:
Vaidyanathan V, D'Souza C, Shetty K. Expect the unexpected: Nonrecurrent laryngeal nerve. Thyroid Res Pract [serial online] 2012 [cited 2022 Dec 7];9:56-7. Available from: https://www.thetrp.net/text.asp?2012/9/2/56/96050

  Introduction Top

Unilateral recurrent laryngeal nerve (RLN) injury may result permanent hoarseness and bilateral in life-threatening dyspnea because of medial placement of the paralytic vocal cords, obstructing the glottis. [1] RLN injury is reported in 0.25%-2.6% of cases, with rates >8% in case of reoperation and variant course. [2] Dissection and visualization of the RLN during such procedures significantly reduces the risk of lesion to this nerve. [3] To accomplish this, it is imperative to have a sound knowledge of the normal and variant forms of the RLN especially nonrecurrent laryngeal nerve (nRLN). [4]

  Case Report Top

A 26-year-old female patient underwent right hemithyroidectomy for colloid goitre involving only the right lobe. Intraoperatively, right nRLN was noted [Figure 1]. This nerve emanated from the right vagus nerve almost at a right angle, entering the larynx 4 cm after its origin. The nerve did not show a recurrent course. The surgery and postoperative period was uneventful and our patient had no change in her voice.
Figure 1: Nonrecurrent laryngeal nerve (B) is seen arising from the vagus nerve (A). nRLN traverses medially to run deep to the inferior border of cricothyroid muscle (D). Common carotid artery (C) is retracted laterally and trachea (T) medially

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  Discussion Top

The reported incidence of the nRLN is widely variable. In the largest series reported, including 6637 observations of the RLN during neck surgery, the frequency of the nRLN was 0.54% (17 cases in 3098) on the right and 0.07% on the left (2 cases in 2846), corresponding to a global prevalence of 0.32%. [5]

This variant of the RLN is most common on the right side. The embryological basis seems to be a vascular disorder known as arteria lusoria in which the fourth right aortic arch is abnormally absorbed. [6] Consequently, this vessel fails to drag the right recurrent laryngeal nerve caudally when the heart descends, and the neck elongates during embryonic development. [7],[8]

nRLN has cervical origin of which three types are described. Type 1 nRLN arises directly from the vagus and runs together with the superior thyroid pedicle; type 2A nRLN follows a transverse path parallel and over the trunk of the inferior thyroid artery; and type 2B follows a transverse path parallel and under the trunk or between the branches of the inferior thyroid artery. [9] We report type 2A nRLN.

  Conclusion Top

Surgeries in the head and neck region that may compromise the RLN are part of everyday clinical and surgical practice. A thorough knowledge of the normal morphology and most frequent variants of the RLN, including its nonrecurrent variant, can help doctors to minimize the risk of iatrogenic lesion to this nerve.

  References Top

1.Lee MS, Lee UY, Lee JH, Han SH. Relative direction and position of recurrent laryngeal nerve for anatomical configuration. Surg Radiol Anat 2009;31:649-55.   Back to cited text no. 1
2.Casella C, Pata G, Nascimbeni R, Mittempergher F, Salerni B. Does extralaryngeal branching have an impact on the rate of postoperative transient or permanent recurrent laryngeal nerve palsy? World J Surg 2009;33:261-5.   Back to cited text no. 2
3.Hermann M, Alk G, Roka R, Glaser K, Freissmuth M. Laryngeal recurrent nerve injury in surgery for benign thyroid diseases: Effect of nerve dissection and impact of individual surgeon in more than 27,000 nerves at risk. Ann Surg 2002;235:261-8.   Back to cited text no. 3
4.Makay O, Icoz G, Yilmaz M, Akyildiz M, Yetkin E. The recurrent laryngeal nerve and the inferior thyroid artery-anatomical variations during surgery. Langenbecks Arch Surg 2008;393:681-5.   Back to cited text no. 4
5.Henry JF, Audiffrit J, Plan M. The nonrecurent inferior laryngeal nerve. Apropos of 19 cases including 2 on the left side. J Chir (Paris) 1985;122:391-7.   Back to cited text no. 5
6.Avisse C, Marcus C, Delattre JF, Marcus C, Cailliez-Tomasi JP, Palot JP, et al. Right nonrecurrent inferior laryngeal nerve and arteria lusoria: The diagnostic and therapeutic implications of an anatomic anomaly. Review of 17 cases. Surg Radiol Anat 1998;20:227-32.   Back to cited text no. 6
7.Defechereux T, Albert V, Alexandre J, Bonnet P, Hamoir E, Meurisse M. The inferior non recurrent laryngeal nerve: A major surgical risk during thyroidectomy. Acta Chir Belg 2000;100:62-7.   Back to cited text no. 7
8.Schneider J, Baier R, Dinges C, Unger F. Retroesophageal right subclavian artery (lusoria) as origin of traumatic aortic rupture. Eur J Cardiothorac Surg 2007;32:385-7.   Back to cited text no. 8
9.Toniato A, Mazzarotto R, Piotto A, Bernante P, Pagetta C, Pelizzo MR. Identification of the nonrecurrent laryngeal nerve during thyroid surgery: 20-year experience. World J Surg 2004;28:659-61.  Back to cited text no. 9


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