The Relationship Between the Non-recurrent Laryngeal Nerve and the Inferior Thyroid Artery

Abstract

The non-recurrent inferior laryngeal nerve (NRLN) represents a risk factor for nerve injury during thyroid surgery. The aim of this study is to investigate the traveling patterns of NRLNs and its relationships to inferior thyroid arteries (ITAs). We had 11 patients showing NRLNs on the right side who underwent thyroidectomies. The NRLNs were classified into four different types, according to the traveling patterns. We evaluated the anatomical position of the ITA as follows: (1) three types according to the joint location with the thyroid gland; and (2) three types according to the level of the retro-esophageal subclavian artery (RSA). The traveling patterns of NRLN could be classified into four types, descending, vertical, ascending, and V-shaped. ITA was joined variably with the thyroid gland on the superior, middle, and inferior positions. The levels of the RSA were also located at different positions, the first thoracic vertebra, the second vertebra, and the third vertebra. During thyroid surgery, the surgeon must be aware of the existence of anatomical variations of NRLNs and ITAs. The anatomy of the NRLN and the ITA are frequently irregular, and there is no correlation between the traveling pattern of NRLN and the level of the RSA.

Systematic Review and Meta-Analysis: Recurrent Laryngeal Nerve Variants and Their Implication in Surgery and Neck Pathologies, Using the Anatomical Quality Assurance (AQUA) Checklist

“…Regarding the sex of the population studied in the articles with a total sample size equal to 1, the following characteristics were identified: 5 subjects were men (27.7%), 12 subjects were women (66.66%), and 1 study did not report the sex of the sample (5.55%). In relation to the 23 studies that presented a sample size greater than 1, the following data were collected: 5 studies [ 8 , 11 , 13 , 28 , 29 ] did not specify the sex of the subjects with a total sample size of 6531 (22.36% of the total sample of studies with a sample greater than 1; 2 studies [ 31 , 32 ] presented only women in their sample, which is equivalent to 10 (0.034% of the total sample of studies with a sample size greater than 1); finally, 16 studies [ 3 , 11 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ] included both men and women in their sample and the following data were obtained: the total number of men was 4849 (16.6%) and that of women was 17,810 (60.99%). Individually, in the studies that presented both men and women, the percentage of men varied between 4.08% and 81% and had a mean of 26.64, while the percentage of women varied between 19% and 95.92% with a mean of 73.36% (see Table 3 ).…”

“…For analysis of data, these studies were grouped into three categories: studies with a prevalence rate greater than 10%, studies with a prevalence rate of less than 10%, and studies with n > 1 but with 100% prevalence. Eight studies had n > 1 and a prevalence of 100%; these studies [ 30 , 31 , 36 , 37 , 43 , 44 , 46 , 67 ] had an N ranging between 2 and 294 and a mean of 64.12 subjects. Six studies [ 32 , 34 , 39 , 40 , 47 , 66 ] had a prevalence greater than 10% and a deviation between 49 and 2404 subjects, and a mean of 1136.7 subjects.…”

“…The prevalence in these studies ranged between 28.7% and 73.72%, with a mean of 41.36%. Finally, we found nine studies with a prevalence rate of less than 10% [ 3 , 13 , 16 , 29 , 33 , 36 , 38 , 41 , 42 ]. The prevalence in these studies ranged from 0.24% [ 12 ] to 6.32% [ 3 ], with a mean prevalence of 3.28%.…”

Intra-operative discovery of nonrecurrent inferior laryngeal nerve: a report of 3 cases including one of left nonrecurrent inferior laryngeal nerve and literature review

“…3 Generally, the left NRLN is accompanied by situs inversus viscerum according to the study conducted by Weatherford. [1][2][3][4] However, Michael et al reported a left-sided NRLN unaccompanied by viscerum anomalies. [2][3][4][5] The NRILN is relatively an exceptional anomaly which has been described only in 0.52 to 0.7% of cases.…”

“…[1][2][3][4] However, Michael et al reported a left-sided NRLN unaccompanied by viscerum anomalies. [2][3][4][5] The NRILN is relatively an exceptional anomaly which has been described only in 0.52 to 0.7% of cases. 2 Between the years 2011 to 2021 inclusive 1511 thyroid operations were performed at endocrine surgery department of Rabat University Hospital Center.…”