Nonrecurrent Laryngeal Nerve: Thyroid Surgeons’ Paradise

Ritesh Agrawal https://orcid.org/0000-0002-8277-9198

Department of Endocrine Surgery, Lilavati Hospital and Research Centre, Mumbai, Maharashtra, India

Corresponding Author: Ritesh Agrawal, Department of Endocrine Surgery, Lilavati Hospital and Research Centre, Mumbai, Maharashtra, India, Phone: +91 7666022022, e-mail: drriteshagrawal@rediffmail.com

ABSTRACT

This article presents a picture of a nonrecurrent laryngeal nerve found during surgery for a benign parathyroid tumor along with a thyroid nodule. The patient had recurrent renal stones, worked up, and was found to have hypercalcemia due to primary hyperparathyroidism along with a nodule in the right lobe of the thyroid. A preoperative computed tomography (CT) scan identified a right aberrant subclavian artery. During surgery, we found a nonrecurrent laryngeal nerve originating from the vagus nerve higher up in the neck and entering directly into the larynx by taking a curved course as shown in the picture. The nerve was saved at full length and postoperatively, and there was no vocal dysfunction.

How to cite this article: Agrawal R. Nonrecurrent Laryngeal Nerve: Thyroid Surgeons’ Paradise. World J Endoc Surg 2022;14(1):35-35.

Source of support: Nil

Conflict of interest: None

Keywords: Aberrant right subclavian artery, Arteria lusoria, Nonrecurrent laryngeal nerve

Recurrent laryngeal nerve (RLN) arises from the vagus nerve, loops around major arteries in the mediastinum (subclavian artery on right side and arch of the aorta on left side precisely), and turns upwards to enter the larynx running in close vicinity to the thyroid gland. Saving this nerve in the whole length is a must for any thyroid surgeon. However, it is not a simple task too. It is the nerve that elevates the status of any surgeon to a thyroid surgeon.

In less than 1% of cases, this RLN is a nonrecurrent one, arising from vagus in the neck only and entering the larynx without making a loop around vessels in the mediastinum. It is quite rare and even a large series of thyroid surgeries validated this incidence.¹^,²

This nonrecurrent nerve is liable to get injured if not suspected preoperatively and the surgeon is not well versed with the anatomical variations. The possibility of nonrecurrent nerve arises when there is an aberrant subclavian artery (arteria lusoria) on the right side on preoperative imaging. The subclavian artery originates from the left arch of the aorta, in this condition, therefore, the nerve could not make a loop around the artery and remains in the neck only.³

This article is to share a picture of nonrecurrent laryngeal nerve found during surgery for a benign parathyroid tumor along with a nodule in the right lobe of the thyroid. The patient, a 54-year-old gentleman had recurrent renal stones, worked up, and was found to have hypercalcemia due to primary hyperparathyroidism. A preoperative CT scan identified a right aberrant subclavian artery hence our surgical team was expecting a nonrecurrent laryngeal nerve before surgery only. During surgery, careful dissection and search confirmed our suspicion that there was a nonrecurrent laryngeal nerve originating from the vagus nerve higher up in the neck and entering directly into the larynx by taking a curved course as shown in the picture (Fig. 1). The nerve was saved at full length and postoperatively, and there was no vocal dysfunction. The picture was taken after the removal of the right lobe of the thyroid with a parathyroid tumor and after completing the dissection.

Fig. 1: Nonrecurrent laryngeal nerve on right side marked as NRLN, after removal of thyroid lobe, trachea marked as T, vagus marked as V, common carotid artery marled as C

It is important for a thyroid surgeon to know the variations in anatomy for RLN and save the nerve always, prefer to do proper imaging in order to identify rare variants and thus be able to save the nerve and prevent vocal cord palsy.

ORCID

Ritesh Agrawal https://orcid.org/0000-0002-8277-9198

REFERENCES

1. Henry JF, Audiffret J, Denizot A, et al. The nonrecurrent inferior laryngeal nerve: review of 33 cases, including two on the left side. Surgery 1988;104(6):977–984.

2. Toniato A, Mazzarotto R, Piotto A, et al. Identification of the nonrecurrent laryngeal nerve during thyroid surgery: 20-year experience. World J Surg 2004;28(7):659–661. DOI: 10.1007/s00268-004-7197-7

3. Myers PO, Fasel JHD, Kalangos A, et al. Arteria lusoria: developmental anatomy, clinical, radiological and surgical aspects. Ann Cardiol Angeiol (Paris) 2010;59(3):147–154. DOI: 10.1016/j.ancard.2009.07.008

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