Thyroid Research and Practice

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

Expect the unexpected: Nonrecurrent laryngeal nerve

Vinay Vaidyanathan1, Caren D'Souza2, Kishore Shetty1,  
1 Department of ENT, K S Hegde Medical Academy, Mangalore, Karnataka, India
2 Department of Surgery, K S Hegde Medical Academy, Mangalore, Karnataka, India

Correspondence Address:
Vinay Vaidyanathan
Department of ENT, K S Hegde Medical Academy, Mangalore, Karnataka-575 018


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.

How to cite this article:
Vaidyanathan V, D'Souza C, Shetty K. Expect the unexpected: Nonrecurrent laryngeal nerve.Thyroid Res Pract 2012;9:56-57

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Vaidyanathan V, D'Souza C, Shetty K. Expect the unexpected: Nonrecurrent laryngeal nerve. Thyroid Res Pract [serial online] 2012 [cited 2020 May 30 ];9:56-57
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Full Text


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

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}


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.


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.


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