Identification of external branch of superior laryngeal nerve in relation to upper pole of thyroid gland in thyroid surgery
DOI:
https://doi.org/10.18203/2320-6012.ijrms20242937Keywords:
External branch of superior laryngeal nerve, Superior thyroid vessels, ThyroidectomyAbstract
Background: One of the most common procedures carried out by otorhinolaryngologists is thyroidectomy. A challenging aspect of thyroid surgery is the prevention of damage to the external branch of the superior laryngeal nerve (EBSLN). The objective of this study is to assess the rate of identification and different anatomical variations of the EBSLN in relation to the upper pole of the thyroid gland during thyroidectomy operation.
Methods: This is a prospective observational study conducted in the Department of Otorhinolaryngology, Silchar Medical College and Hospital, Silchar, Assam involving 25 patients who underwent thyroidectomy between January 2023, and December 2023. The study included patients aged 20 years and older who fulfilled the specified inclusion and exclusion criteria. The traditional open thyroidectomy technique was used for each procedure, using a standard Kocher's skin incision. We categorised the anatomical course of the EBSLN in relation to upper pole of the thyroid gland.
Results: In this study, out of the 29 EBSLN, 24 (82.35%) nerves were successfully identified, whereas 5 (17.64%) nerves could not be identified. Out of 24 EBSLN, we found 20 (68.97%) nerves crossing superior thyroid vessels above the upper pole of the thyroid gland and 4 (13.79%) nerves crossing underneath the upper pole of the thyroid gland.
Conclusions: We should direct our dissection more carefully in the region above the upper pole of the thyroid, as the majority of EBSLN crosses the superior thyroid vessels above the upper pole of the thyroid gland. We should also avoid extensive dissection in search of EBSLN, keeping in mind that some nerve branches that cross the superior thyroid vessels under the cover of the upper pole of the thyroid gland put patients at greater risk for injury during thyroidectomy.
References
Joshi RR, Rijal AS, Shrestha KK, Dhungana A, Maharjan S. Identification and preservation of external branch of the superior laryngeal nerve during thyroid surgeries at NMCTH. J Coll Medi Sciences-Nepal. 2017;13(3):306-10.
Uludag M, Aygun N, Kartal K, Citgez B, Besler E, Yetkin G, et al. Contribution of intraoperative neural monitoring to preservation of the external branch of the superior laryngeal nerve: a randomized prospective clinical trial. Langenbeck's Arch Surg. 2017;402:965-76.
Barczyński M, Randolph GW, Cernea CR, Dralle H, Dionigi G, Alesina PF, et al. External branch of the superior laryngeal nerve monitoring during thyroid and parathyroid surgery: International Neural Monitoring Study Group standards guideline statement. Laryngoscope. 2013;123:S1-4.
Kochilas X, Bibas A, Xenellis J, Anagnostopoulou S. Surgical anatomy of the external branch of the superior laryngeal nerve and its clinical significance in head and neck surgery. Clin Anat: J Ame Assoc Clin Anatom Brit Asso Clin Anat. 2008;21(2):99-105.
Morton R, Whitfield P, Al-Ali S. Anatomical and surgical considerations of the external branch of the superior laryngeal nerve: a systematic review. Clin Otolaryngol. 2006;31(5):368-74.
Soylu L, Ozbas S, Uslu HY, Kocak S. The evaluation of the causes of subjective voice disturbances after thyroid surgery. Am J Surg. 2007;194(3):317-22.
Kark AE, Kissin MW, Auerbach R, Meikle M. Voice changes after thyroidectomy: role of the external laryngeal nerve. Br Med J (Clin Res Ed). 1984;289(6456):1412-5.
Aluffi P, Policarpo M, Cherovac C, Olina M, Dosdegani R, Pia F. Post-thyroidectomy superior laryngeal nerve injury. Euro Arch Oto-Rhino-Laryngol. 2001;258:451-4.
Friedman M, LoSavio P, Ibrahim H. Superior laryngeal nerve identification and preservation in thyroidectomy. Arch Otolaryngol–Head Neck Surg. 2002;128(3):296-303.
Eckley CA, Sataloff RT, Hawkshaw M, Spiegel JR, Mandel S. Voice range in superior laryngealnerve paresis and paralysis. J Voice. 1998;12(3):340-8.
Delbridge L. The ‘neglected’nerve in thyroid surgery: the case for routine identification of the external laryngeal nerve. ANZ J Surg. 2001;71(4):199-.
Kerian K. Comparing the morbidity of external laryngeal nerve injury in thyroid surgery with and without identifying the nerve using intraoperative neuromonitoring. Med J Malaysia. 2012;67(3):289.
Eisele DW, Goldstone AC. Electrophysiologic identification and preservation of the superior laryngeal nerve during thyroid surgery. Laryngosc. 1991;101(3):313-5.
Teitelbaum BJ, Wenig BL. Superior laryngeal nerve injury from thyroid surgery. Head Neck. 1995;17(1):36-40.
Wu BL, Sanders I, Mu L, Biller HF. The human communicating nerve: an extension of the external superior laryngeal nerve that innervates the vocal cord. Arch Otolaryngol–Head Neck Surg. 1994;120(12):1321-8.
Sanders I, Wu BL, Mu L, Li Y, Biller HF. The innervation of the human larynx. Arch Otolaryngol–Head Neck Surg. 1993;119(9):934-9.
Gray H. Anatomy of the Human Body. Philadelphia: Lea &Febiger; 1918:910-913.
Cernea CR, Ferraz AR, Furlani J, Monteiro S, Nishio S, Hojaij FC, et al. Identification of the external branch of the superior laryngeal nerve during thyroidectomy. Amer J Surg. 1992;164(6):634-9..
Glover AR, Norlén O, Gundara JS, Morris M, Sidhu SB. Use of the nerve integrity monitor during thyroid surgery aids identification of the external branch of the superior laryngeal nerve. Ann Surg Oncol. 2015;22:1768-73.
Athvale PK, Bokare BD, Ekhar VR. Identification and Preservation of External branch of superior laryngeal nerve in Thyroidectomy. Int J Phonosurg Laryngol. 2013;3(2):39-41.
Aina EN, Hisham AN. External laryngeal nerve in thyroid surgery: recognition and surgical implications. ANZ J Surg. 2001;71(4):212-4.
Mishra AK, Temadari H, Singh N, Mishra SK, Agarwal A. The external laryngeal nerve in thyroid surgery: the ‘no more neglected’ nerve. Ind J Med Sci. 2007;61(1):3-8.
