Topographic anatomy of the thyroid gland and recurrent laryngeal nerve in cadavers: A descriptive cross-sectional cadaveric study with surgical relevance.

Ashok  Aenumulapalli; Sravanthi  Repalle; Deepika  Vazir

doi:10.51168/sjhrafrica.v6i6.1759

Authors

Dr. Ashok Aenumulapalli Associate Professor, Department of Anatomy, Prathima Relief institute of medical sciences, Warangal, Telangana, India.
Dr. Sravanthi Repalle Associate Professor, Department of Anatomy, Government Medical College, Narsampet, Warangal, Telangana, India.
Deepika Vazir Associate Professor, Department of Anatomy, Government Medical College, Mulugu, Telangana, India.

DOI:

https://doi.org/10.51168/sjhrafrica.v6i6.1759

Keywords:

Recurrent laryngeal nerve, Thyroid gland, Inferior thyroid artery, Anatomical variations, Cadaveric study, Tracheoesophageal groove, Extra laryngeal branching, Thyroidectomy

Abstract

Background:
Injury to the recurrent laryngeal nerve (RLN) is a significant complication of thyroid surgery. Due to its variable anatomical course and relationship with the thyroid gland and inferior thyroid artery, thorough anatomical understanding is essential to minimize surgical risk.

Objective:

To evaluate the anatomical variations of the RLN about the thyroid gland and inferior thyroid artery in adult cadavers, with emphasis on surgical relevance.

Methods:

A descriptive study was performed on 20 formalin-fixed adult cadavers (40 heminecks). Bilateral dissections were conducted to assess the RLN's position (in or outside the tracheoesophageal groove), its relationship with the inferior thyroid artery, extra laryngeal branching, and laryngeal entry level. Observations were recorded and analyzed using descriptive statistics.

Results:

The RLN was located within the tracheoesophageal groove in 85% of heminecks. It lay posterior to the inferior thyroid artery in 57.5%, anterior in 25%, and between its branches in 17.5%. Extra laryngeal branching was observed in 12.5%, more often on the right. In 10% of cases, the nerve entered the larynx at a higher-than-usual level. Asymmetry between the right and left sides occurred in 20% of cadavers. No statistically significant side differences were noted (p > 0.05).

Conclusion:

The recurrent laryngeal nerve exhibits notable anatomical variations that hold significant surgical relevance. Awareness of these variations is critical for preventing nerve injury during thyroidectomy.

Recommendations:

Surgeons should carefully identify the RLN during dissection, avoid blind ligation near the inferior thyroid artery, use intraoperative nerve monitoring, when possible, integrate cadaveric training in surgical education, and consider preoperative imaging for detecting anatomical variations.

Author Biographies

Dr. Ashok Aenumulapalli, Associate Professor, Department of Anatomy, Prathima Relief institute of medical sciences, Warangal, Telangana, India.

Dr. Ashok Aenumulapalli is a highly qualified academician and researcher in the field of Medical Anatomy, with extensive experience in teaching, research, and interdisciplinary collaboration. His academic journey reflects a strong commitment to medical education and anatomical sciences. He began his undergraduate studies in physiotherapy, earning his Bachelor of Physiotherapy (BPT) from Kakatiya College of Physiotherapy, Warangal, in the period 2002–2007. With a growing interest in anatomical sciences, he pursued postgraduate education and obtained his M.Sc in Medical Anatomy from Mamata Medical College, Khammam, between 2008 and 2012. To further strengthen his academic and research capabilities, Dr. Aenumulapalli earned his Ph.D. in Medical Anatomy from the prestigious Sumandeep Vidyapeeth, Vadodara, Gujarat, completing it in 2017. His doctoral work reflects a deep engagement with the structural and functional intricacies of human anatomy and a drive toward advancing anatomical education. He has published over 25 research articles in reputed international journals indexed in DOAJ, EMBASE, SCOPUS, and PubMed Central, contributing significantly to the global body of anatomical and medical education literature. Throughout his academic career, he has been actively involved in teaching undergraduate and postgraduate students, contributing to curriculum development, and promoting innovative teaching methodologies. His areas of interest include neuroanatomy, histology, and anatomical variations, with a strong emphasis on clinical relevance and interdisciplinary integration. Dr. Aenumulapalli remains dedicated to continuous learning, research publication, and participation in academic conferences, where he shares his insights and contributes to scholarly discourse in anatomy and allied medical sciences. Dr. Aenumulapalli ORCiD is https://orcid.org/0009-0001-3984-4118

Dr. Sravanthi Repalle, Associate Professor, Department of Anatomy, Government Medical College, Narsampet, Warangal, Telangana, India.

Dr. Sravanthi Repalle serves as an Associate Professor in the Department of Anatomy at Government Medical College, Narsampet, Telangana. She obtained her undergraduate medical degree (MBBS) from Kakatiya Medical College, Hanumakonda, Warangal (2000–2005), followed by a postgraduate degree (MD in Anatomy) from the same institution (2008–2011). With over a decade of experience in teaching undergraduate medical students, Dr. Repalle has contributed significantly to anatomical education and research. Her primary research interests include morphometric analyses, anatomical variations of major structures such as the brachial artery, cervical vertebrae, and cruciate ligaments, and the integration of clinical relevance in anatomical education. She has published over 25 scientific papers as first author, corresponding author, and co-author in several reputed indexed journals including EMBASE, SCOPUS, DOAJ, and Index Copernicus. Her studies have ranged from cadaveric dissections to educational research, including investigations into organ donation awareness and integrated teaching methodologies. Dr. Repalle remains committed to advancing anatomical science through both rigorous academic instruction and meaningful research contributions. She also actively participates in academic conferences and workshops aimed at strengthening anatomy education in India. Dr. Repalle ORCiD is https://orcid.org/ 0000-0003-0535-3246

Deepika Vazir, Associate Professor, Department of Anatomy, Government Medical College, Mulugu, Telangana, India.

Dr. Deepika Vazir is an experienced academician and medical educator in the field of Anatomy, currently serving as an Associate Professor in the Department of Anatomy at Government Medical College, Mulugu. With over a decade of involvement in medical teaching and academic leadership, she is known for her dedication to foundational medical sciences and her commitment to shaping future healthcare professionals. She pursued her undergraduate medical education (MBBS) from SVS Medical College, Mahbubnagar, between 2001 and 2007. Following her passion for anatomical sciences, she completed her postgraduate degree—MD in Anatomy—from Mediciti Institute of Medical Sciences, Ghanpur, Hyderabad, in 2015. She has authored more than 15 research articles published in esteemed international journals indexed in DOAJ, EMBASE, SCOPUS, and PubMed Central, making valuable contributions to the global literature in anatomical and medical education. Dr. Vazir actively engages in academic teaching, curriculum development, and student mentorship. Her areas of interest include gross anatomy, histology, and embryology, with a focus on integrating modern pedagogical techniques into anatomical education. She maintains a strong commitment to academic excellence and regularly participates in faculty development programs, workshops, and medical education forums. Dr. Vazir ORCiD is https://orcid.org/ 0000-0003-0535-3246

References

Wu H, Zhang D, Li H, Zhang M, Jin X. Anatomical relationships of recurrent laryngeal nerve with the thyroid gland and its surgical implications: a meta-analysis. Surg Radiol Anat. 2023;45(3):293–301. https://doi.org/10.1007/s00276-022-03043-5

Song CM, Lee YS, Jung SL, Bae JS, Kim SW. Recurrent laryngeal nerve injury during thyroidectomy: anatomical considerations and surgical strategies to prevent nerve damage. Clin Exp Otorhinolaryngol. 2022;15(1):12–19. https://doi.org/10.21053/ceo.2021.00445

Cai Y, Xie L, Zhu J, Sun X, Han B. Non-recurrent laryngeal nerve: a systematic review and meta-analysis of 27,356 thyroid surgery cases. Langenbecks Arch Surg. 2021;406(3):649–656. https://doi.org/10.1007/s00423-021-02061-9

Chhetri RK, Yadav PK, Joshi RR, Paudel S, Khanal R. Anatomical variations of recurrent laryngeal nerve: findings from a cadaveric study in a tertiary medical college. Nepal Med Coll J. 2021;23(1):10–14. https://doi.org/10.3126/nmcj.v23i1.36664

Cirocchi R, Arezzo A, D'Andrea V, et al. Recurrent laryngeal nerve injury in thyroid surgery: a review of the literature. Gland Surg. 2019;8(Suppl 1):S52–S61. https://doi.org/10.21037/gs.2018.09.10

Barczyński M, Randolph GW, Cernea CR, et al. External branch of the superior laryngeal nerve monitoring during thyroid and parathyroid surgery: international neural monitoring study group standards guideline. Laryngoscope. 2021;131(S1):S1–S17. https://doi.org/10.1002/lary.29229

Henry BM, Sanna S, Graves MJ, et al. The surgical anatomy of the recurrent laryngeal nerve: a meta-analysis and clinical considerations. Laryngoscope. 2017;127(1):E13–E21. https://doi.org/10.1002/lary.26101

Makay O, Icoz G, Yilmaz M, Akyildiz M, Ertan T, Akgun I. The recurrent laryngeal nerve and the inferior thyroid artery—anatomical variations during thyroidectomy. Surg Today. 2005;35(7):518–521. https://doi.org/10.1007/s00595-005-2989-1

Zakaria HM, Al Awad NA, Al Kreedes AS, Al-Mulhim AM, Al-Sharway MA, Hadi MA, Al Sayyah AA. Recurrent laryngeal nerve injury in thyroid surgery. Oman Med J. 2011 Jan;26(1):34-8. doi: 10.5001/omj.2011.09.

Aytac B, Karamercan A. Recurrent laryngeal nerve injury and preservation in thyroidectomy. Saudi Med J. 2005 Nov;26(11):1746-9.

Pandey AK, Varma A, Bansal C, Bhardwaj A. An Exposition on Surgical Experiences in Identification, Exposure, and Injuries of Recurrent Laryngeal Nerve (RLN) During Thyroid Operations: Gleanings, Narrative, and the Reflections. Indian J Otolaryngol Head Neck Surg. 2023 Sep;75(3):1363-1369. doi: 10.1007/s12070-023-03541-7.

Friedrich T, Steinert M, Keitel R, Sattler B, Schönfelder M. The incidence of recurrent laryngeal nerve lesions after thyroid surgery: a retrospective analysis. Zentralbl Chir 1998;123:25-29

Gonçalves Filho J, Kowalski LP. Surgical complications after thyroid surgery performed in a cancer hospital. Otolaryngol Head Neck Surg 2005. Mar;132(3):490-494 10.1016/j.otohns.2004.09.028

Hisham AN, Lukman MR. Recurrent laryngeal nerve in thyroid surgery: a critical appraisal. ANZ J Surg 2002. Dec;72(12):887-889 10.1046/j.1445-2197.2002.02578.x

Donatini G, Carnaille B, Dionigi G. Risks and benefits of intraoperative neuromonitoring in thyroid surgery: a systematic review. Langenbecks Arch Surg. 2020;405(6):863–873. https://doi.org/10.1007/s00423-020-01887-5