Abstract

Introduction: Thyroid surgery is currently considered an important pillar in the treatment of certain pathologies. In Senegal, the persistence of goiter after medical treatment justifies multiple thyroidectomies with their cohort of significant risks of vital or functional complications. In this context we undertook this work in order to study the anatomical variations in the number of parathyroid glands as well as the relationships of the inferior thyroid artery (ITA) with the recurrent laryngeal nerves (RLN). Taking these variations into account is important during thyroid surgery in our population. Material and Method: this was a descriptive cross-sectional anatomical study by dissection of 43 thyroids taken from adult anatomical subjects of both sexes without visible scars or lesions on the anterior face of the neck. The number of parathyroid glands, the ratios between NLR and ATI, and certain correlations were studied and statistically analyzed. Results: The left NLR was predominantly retrovascular compared to the ipsilateral ATI in 70% of cases, then prevascular, and finally in 26% of cases, and transvascular for the remainder. On the right, it followed the same slope as on the left, with a retrovascular majority of 50% of cases. All the parathyroid glands found were posterior; the majority of specimens (72%) had 4, followed by 20% with 2, and 6% with 1. Conclusion: The dissection of the thyroid allowed us to highlight the diversity of the relationships between the recurrent laryngeal nerves and the ATI, but also that of the number of parathyroid glands. Taking these anatomical variations into account will help to avoid certain post-thyroidectomy omplications.

• 1.   Schaffler A, Menche N, Prudhomme C. Anatomie-physiologie-biologie. 2e édition. Maloine, 2004.
• 2.   Niang F, Loum B, Diouf M. Morphologie et rapports du nerf laryngé inférieur avec l’artère thyroïdienne inférieure à propos de 40 thyroïdectomies. RECAC.2023; 4: 15–22.
• 3.   Hemmaoui B, Sahli M, Errami N, et al. Le nerf laryngé inférieur: considérations anatomiques et chirurgicales à propos de 60 thyroïdectomies. The Pan African Medical Journal; 33. Epub ahead of print 27 May 2019. DOI: 10.11604/ pamj.2019.33.58.14271.
• 4.   Elgazzar AH. The Pathophysiologic Basis of Nuclear Medicine. Springer Berlin Heidelberg, 2001.
• 5.   N’dri K, Konaté I, Abby BC, et al. Les dimensions normales de la thyroide a l’echographie. Rev Col Odonto-Stomatol Afr Chir Maxillo-fac 2006; 13: 19–23.
• 6.   Tsujio M, Watahiki Y, Yoshioka K, et al. Morphology of Thyroid Follicular Cells of Methimazole-treated Rats. Anat Histol Embryol 2007; 36: 290–294.
• 7.   Hojaij F, Vanderlei F, Plopper C, et al. Parathyroid gland anatomical distribution and relation to anthropometric and demographic parameters: a cadaveric study. Anat Sci Int 2011; 86: 204–212.
• 8.   Grassetto G, Alavi A, Rubello D. PET and Parathyroid. PET Clin 2007; 2: 385–393.
• 9.   Lefevre JH, Tresallet C, Leenhardt L, et al. Reoperative surgery for thyroid disease. Langenbecks Arch Surg 2007; 392: 685–691.
• 10.   Noussios G, Chatzis I, Konstantinidis S, et al. The Anatomical Relationship of Inferior Thyroid Artery and Recurrent Laryngeal Nerve: A Review of the Literature and Its Clinical Importance. J Clin Med Res 2020; 12: 640–646.
• 11.   Sultana SZ, Khan MK, Rahman H, et al. Morphological study of recurrent laryngeal nerve in relation to thyroid gland. Mymensingh Med J 2006; 15: 192–196.
• 12.   Ozgüner G, Sulak O. Arterial supply to the thyroid gland and the relationship between the recurrent laryngeal nerve and the inferior thyroid artery in human fetal cadavers. Clin Anat 2014; 27: 1185–1192.
• 13.   Kaisha W, Wobenjo A, Saidi H. Topography of the recurrent laryngeal nerve in relation to the thyroid artery, Zuckerkandl tubercle, and Berry ligament in Kenyans. Clin Anat 2011; 24: 853–857.
• 14.   Henry BM, Vikse J, Graves MJ, Sanna S, Sanna B, Tomaszewska IM, Hsieh WC, Tubbs RS, Tomaszewski KA. Variable relationship of the recurrent laryngeal nerve to the inferior thyroid artery: A meta-analysis and surgical implications. Head Neck 2017, 39(1):177-186.
• 15.   Adèle-Rose N. Les repères chirurgicaux du nerf laryngé inférieur diffèrent-ils selon les ethnies ? Revue Médicale Suisse. 2020;16(709):1849- 1853.
• 16.   Ngo-Nyeki AR, Triponez F, Guyot JP. Les repères chirurgicaux du nerf laryngé inférieur diffèrent-ils selon les ethnies? Rev Med Suisse. 7 oct 2020;709:1849 52.
• 17.   Skandalakis JE, Colborn GL, Weidman TA, et al. Surgical Anatomy : The Embryologic and Anatomic Basis of Modern Surgery. Paschalidis Medical Publications; 2004.
• 18.   Kostek M, Caliskan O, Yanar C, Cakir Y, Uludag M. The Most Common Anatomical Variation of Recurrent Laryngeal Nerve: Extralaryngeal Branching. Sisli Etfal Hastan Tip Bul. 2021;55(3):294 303.
• 19.   Aygun N, Unlu MT, Caliskan O, Kostek M, Isgor A, Uludag M. The relation of recurrent laryngeal nerve to inferior thyroid artery and extralaryngeal nerve branching may increase the risk of vocal cord paralysis in thyroidectomy. Langenbecks Arch Surg. 2024, 27;409(1):198.

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