Identification of external branch of superior laryngeal nerve during thyroid surgery: a prospective study
Keywords:EBSLN, Joll’s triangle, Cernea Classification, goiters
Background: Identification of external branch of superior laryngeal nerve (EBSLN) according to Cernea et al classification and to describe a surgical technique of superior pole dissection to preserve EBSLN during thyroid surgeries.
Methods: The study was done over 2 years period in a tertiary care hospital. 105 nerves were studied among the 90 patients who underwent thyroid surgeries. Avascular dissection over the JOLL’S triangle was carried out and identified EBSLN were classified according to Cernea et al classification. Individual ligation of superior pole vessels was carried out after identifying the nerve. Outcome was studied relating the identified nerve with sides of thyroidectomy performed, size of thyroid gland and nerves at risk according to Cernea et al classification.
Results: Of the 105 nerves studied, in 81.90% of patients the nerve was identified. There were 34.88% of Type 1 nerves, 52.33% of Type 2A nerve and 12.79% of Type 2B nerves identified. Less number of nerves could be identified on the left side. Type 2B nerves were more common on left side inspite of less number of dissections carried out on left. Type 2 variation was more common in large goiters.
Conclusions: Careful dissection should be done in superior pole in avascular cricothyroid space, with lateralization of superior pole and individual identification of superior pole vessels once the nerve is identified. Identification of the nerve is mandatory in all patients who undergo thyroid surgery for optimal functions of the larynx. These results showed a better identification of nerves by proper surgical techniques without use of any sophisticated equipments.
Wagner HE, Seiler C. Recurrent laryngeal nerve palsy after thyroid gland surgery. Br J Surg. 1994;81:226–8.
Delbridge L, Reeve TS, Khadra M, Poole AG. Total thyroidectomy: The technique of capsular dissection. Aust N Z J Surg. 1992;62:96–9.
Lekacos NL, Miligos ND, Tzardis PJ, Majiatis S, Patoulis J. The superior laryngeal nerve in thyroidectomy. Am Surg. 1987;53:610–2.
Lennquist S, Cahlin C, Smeds S. The superior laryngeal nerve in thyroid surgery. Surgery. 1987;102:999–1008.
Cernea CR, Ferraz AR, Nishio S, Dutra A Jr, Hojaij FC, dos Santos LR. Surgical anatomy of the external branch of the superior laryngeal nerve. Head Neck. 1992;14:380–3.
Hanks JB. In: Sabiston Textbook of Surgery Har Court Asia Private Limited and W. B. Saunders Company. 2001;16:605-15.
Lore JM, Kokocharov SI, Richmond A, Kaufman S, Sundquist N. 38 Year evaluation of a surgical technique to prevent the EBSLN during thyroidectomy. Ann Otol Rhinol Laryngol. 1998;107:1015-22.
Kark AE, Kissin MW, Auerbach R, Meikle M. Voice change after thyroidectomy: role of the external laryngeal nerve. Br Med J. 1984;289:1412-5.
Aina EN, Hisham AN. External laryngeal nerve in thyroid surgery: is the nerve stimulator necessary? Eur J Surg. 2001;167:662-5.
Mishra AK, Temadari H, Singh N. The external laryngeal nerve in thyroid surgery, the ‘no more neglected ‘nerve. Indian J Med sci. 2007;61(1):3-8.
Hwang SB, Lee HY. The anatomy of the external branch of superior Laryngeal nerve in Koreans. Asian J Surg. 2013;36:13-9.
Naidoo D, Boon JM, Mieny CJ, Becker PJ, van Schoor AN. Relation of the external branch of the superior laryngeal nerve to the superior pole of the thyroid gland: an anatomical study. Clin Anat. 2007;20:516–20.
Friedman M, LoSavio P, Ibrahim H. Superior laryngeal nerve identification and preservation in thyroidectomy. Arch Otolaryngol. 2002;128(3):296-303.