Variations in the origin of inferior thyroid artery and relation of the artery with recurrent laryngeal nerve

Abstract

Background and aim : Thyroid surgery being a major surgery & quite often performed, a thorough knowledge of variations in arterial supply is very essential for surgeons to prevent alarming number of table deaths in patients with thyroid disease due to excessive and uncontrollable bleeding . It also helps the physicians for proper physical examination and treatment of the patient and to the anatomists for learning the variant patterns. Materials & methods: Fifty five adult human cadavers(45 males,10 females)aged between 25 to 50 years and 25 foetuses (18 female,7 male) aged between 24 to 34 weeks were studied by gross dissection. Results: The inferior thyroid artery was found to be absent in 5% of cases. The level of branching of inferior thyroid artery was also studied where in 23.1 % of cases the artery divides before piercing the surgical capsule of thyroid gland and in 76.97%, it divided after piercing the surgical capsule.The relationship of the artery to the recurrent laryngeal nerve was also studied where in 52.6% of cases, either the artery or its branches were anterior to the nerve, in 26.3% of cases the artery or its branches were posterior to the recurrent laryngeal nerve and in 21.1 % of cases the nerve was intermingled with the branches of artery. Conclusion: From the present study it is concluded that the knowledge of variation of the arterial supply can be used during thyroidectomy where in ligation of all the thyroid vessels is highly essential to ensure proper homeostasis.

Considerations on the Origin of the Inferior Thyroid Artery Emerging from the Subclavian Artery Determined by Ct Examination

“…The distance between the origin of the ITA and the origin of the SCA [7] states an average of 15.9 mm, this measurement being smaller than the one in our study with 14.1 -38.1 mm for the male gender and with 16.8 -31.9 mm for the female gender. The distance between the origin of the TCT and the origin of the SCA, comparing to [7], in our study had a higher value with 13.1 -60.0 mm for the male gender and 7.5 -37.2 mm for the female gender From the studied literature, only [10] realized his study on CTA, the other authors got their results from cadavers. Comparing the results, we obtained and the ones from the literature we consulted we found differences, sometimes signi cant ones, regarding the origin of the ITA from the TCT or directly from the SCA.…”

“…In our study, the ITA was present in all the explored cases, [1] a rms that it can be absent sometimes on one side, and [5] states that in 3% of the cases it was missing. [7] didn't nd it in 3,75% on the right side of the examined cases and in 6,25% on the left side. [8] found it missing in 8.43% of cases while [9] didn't nd it in 1-6% of the cases.…”

“…[8] found it missing in 8.43% of cases while [9] didn't nd it in 1-6% of the cases. [2,3,4,7] mention the possibility of the ITA originating directly from the SCA. (Table 1)…”

Relationship between Inferior Thyroid Artery and Recurrent Laryngeal Nerve - A Study of 200 Cases

“…Absence Of ITA (unilateral Or bilateral) have also been reported in previous studies. 6,7,8,9,10 The recurrent laryngeal nerves branch from the vagus nerve, relative to which they get their names; the term "recurrent" from Latin: re-(back) and currere (to run), indicates they run in the opposite direction to the vagus nerves from which they branch. The vagus nerves run down into the thorax, and the recurrent laryngeal nerves run up to the larynx.…”

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

“…The RLN passes anterior to the ITA on the right side and posterior to the ITA on the left side, in most cases. Occasionally, the RLN lies in between the branches of the ITA [4,5].…”