Anatomical landmarks of the external branch of the superior laryngeal nerve

Viktor Y. Malyuga; Aleksandr A. Kuprin

Anatomical landmarks of the external branch of the superior laryngeal nerve

Viktor Y. Malyuga, Aleksandr A. Kuprin

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Abstract

Background. The external branch of the superior laryngeal nerve innervates a cricothyroid muscle, which provides tension in vocal cords and formation of high-frequency sounds. When the nerve is damaged during surgery, patients may notice hoarseness, inability to utter high pitched sounds, “rapid fatigue” of the voice, and dysphagia. According to literature, paresis of an external branch of the superior laryngeal nerve reaches up to 58% after thyroid surgery.

Aim: to identify permanent landmarks and topographic variations of the external branch of the superior laryngeal nerve.

Materials and methods. The study is based on the autopsy material (21 complexes organs of the neck) and on identification of variations of 40 external branches of the superior laryngeal nerve. We identified two permanent landmarks that are located at the minimum distance from nerve and we made metrical calculations relative to them: oblique line of thyroid cartilage and tendinous arch of the inferior pharyngeal constrictor muscle.

Results. The piercing point of the nerve is always located at the inferior pharyngeal constrictor muscle without protruding beyond the oblique line of thyroid cartilage superiorly and tendinous arch of the inferior pharyngeal constrictor muscle anteriorly. The nerve had the parallel direction in 92.8% of cases (angel less than 30 degrees) relative to the oblique line and in 85.7% cases it was in close proximity to this line (at distance up to 4 mm).

The proposed topographic classification of the location of the external branch of the superior laryngeal nerve is based on localization of the piercing point of the nerve relative to the length of the oblique line of thyroid cartilage and the risk of nerve damage. In 14.2% of cases, the piercing point was in the front third of the line (type I), and in 50% it was in the middle third of this line (type II). These variations of the external branch of the superior laryngeal nerve was in close proximity to the upper pole of the thyroid gland, which could have lead to its damage during surgery. In type III and IV (35.8%) – the piercing point in the muscle was located as far as possible from the upper pole of the thyroid gland and the greater part of the nerve was covered with the fibers of inferior pharyngeal constrictor muscle.

Conclusion. We identified the main orienteers for the search and proposed anatomical classification of the location of the external branch on the superior laryngeal nerve.

Keywords

external branch of the superior laryngeal nerve, larynx innervation, thyroid surgery

About the Authors

Viktor Y. Malyuga

E.O. Mukhin city clinical hospital

Russian Federation

MD, PhD

Aleksandr A. Kuprin

A.K. Eramishanzev city clinical hospital

Russian Federation

MD, PhD

References

1. Marchese-Ragona R, Restivo DA, Mylonakis I, et al. The superior laryngeal nerve injury of a famous soprano, Amelita Galli-Curci. Acta Otorhinolaryngol Ital. 2013;33(1):67-71.

2. Бондаренко В.О. Возвратный гортанный нерв в хирургии щитовидной и паращитовидной желез. Атлас. – М.; 2006. [Bondarenko VO. Vozvratnyy gortannyy nerv v khirurgii shchitovidnoy i parashchitovidnoy zhelez. Atlas. Moscow; 2006. (In Russ.)]

3. Румянцев П.О. Интраоперационный нейромониторинг в тиреоидной хирургии. // Эндокринная хирургия. – 2013. – Т. 7. – №3. – С. 32-40. [Rumyantsev PO. Intaoperative neuromonitoring in thyroid surgery. Endocrine surgery. 2013;7(3):32-40 (In Russ.)] doi: https://doi.org/10.14341/serg2013332-40.

4. Barczynski 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 statement. Laryngoscope. 2013;123 Suppl 4:S1-14. doi: https://doi.org/10.1002/lary.24301.

5. Малюга В.Ю., Куприн А.А. Клинико-анатомические особенности кровоснабжения околощитовидных желез: серия наблюдений на аутопсийном материале. // Эндокринная хирургия. – 2018. – Т. 12. – №1. – С. 40-54. [Malyuga VY, Kuprin AA. Clinical and anatomical features of blood supply of parathyroid glands: autopsy case series. Endocrine surgery. 2018;12(1):40-54. (In Russ.)] doi: https://doi.org/10.14341/serg9637.

6. Friedman M, Ibrahim H. Superior laryngeal nerve identification and preservation in thyroidectomy. Oper Tech Otolayngol Head Neck Surg. 2002;13(3):203-206. doi: https://doi.org/10.1053/otot.2002.36443.

7. Whitfield P, Morton RP, Al-Ali S. Surgical anatomy of the external branch of the superior laryngeal nerve. ANZ J Surg. 2010;80(11):813-816. doi: https://doi.org/10.1111/j.1445-2197.2010.05440.x.

8. Cernea CR, Ferraz AR, Furlani J, et al. Identification of the external branch of the superior laryngeal nerve during thyroidectomy. Am J Surg. 1992;164(6):634-639. doi: https://doi.org/10.1016/s0002-9610(05)80723-8.

9. Cernea CR, Ferraz AR, Nishio S, et al. Surgical anatomy of the external branch of the superior laryngeal nerve. Head Neck. 1992;14(5):380-383. doi: https://doi.org/10.1002/hed.2880140507.

10. Estrela F, Záquia Leão H, Pereira Jotz G. Anatomic relation between the external branch of the superior laryngeal nerve and the thyroid gland. Braz J Otorhinolaryngol. 2011;77(2):249-258. doi: https://doi.org/10.1590/s1808-86942011000200016.

11. Potenza AS, Araujo Filho VJF, Cernea CR. Injury of the external branch of the superior laryngeal nerve in thyroid surgery. Gland Surg. 2017;6(5):552-562. doi: https://doi.org/10.21037/gs.2017.06.15.

12. Varaldo E, Ansaldo GL, Mascherini M, et al. Neurological complications in thyroid surgery: a surgical point of view on laryngeal nerves. Front Endocrinol (Lausanne). 2014;5:108. doi: https://doi.org/10.3389/fendo.2014.00108.

13. Карадимитров Г.Н. Профилактика повреждений верхнего гортанного нерва при операциях на щитовидной железе: Дис. ... канд. мед. наук. – М.; 2009. [Karadimitrov GN. Profilaktika povrezhdeniy verkhnego gortannogo nerva pri operatsiyakh na shhitovidnoy zheleze [dissertation]. Moscow; 2006. (In Russ.)]

14. 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. 2008;21(2):99-105. doi: https://doi.org/10.1002/ca.20604.

15. Cha YH, Moon SY, Jehoon O, et al. Anatomy of the external branch of the superior laryngeal nerve in Asian population. Sci Rep. 2017;7(1):14952. doi: https://doi.org/10.1038/s41598-017-15070-9.

16. Bellantone R, Boscherini M, Lombardi CP, et al. Is the identification of the external branch of the superior laryngeal nerve mandatory in thyroid operation? Results of a prospective randomized study. Surgery. 2001;130(6):1055-1059. doi: https://doi.org/10.1067/msy.2001.118375.

17. Selvan B, Babu S, Paul MJ, et al. Mapping the compound muscle action potentials of cricothyroid muscle using electromyography in thyroid operations: a novel method to clinically type the external branch of the superior laryngeal nerve. Ann Surg. 2009;250(2):293-300. doi: https://doi.org/10.1097/SLA.0b013e3181b17342.

18. Lennquist S, Cahlin C, Smeds S. The superior laryngeal nerve in thyroid surgery. Surgery. 1987;102(6):999-1008.

19. Folk D, Wahba B, Sasaki CT. Is the external branch of the superior laryngeal nerve dispensable in thyroid surgery? Thyroid. 2016;26(1):169-173. doi: https://doi.org/10.1089/thy.2015.0457.

20. Hydman J, Mattsson P. Collateral reinnervation by the superior laryngeal nerve after recurrent laryngeal nerve injury. Muscle Nerve. 2008;38(4):1280-1289. doi: https://doi.org/10.1002/mus.21124.

21. Sañudo J-R, Maranillo E, León X, et al. An anatomical study of anastomoses between the laryngeal nerves. Laryngoscope. 1999;109(6):983-987. doi: https://doi.org/10.1097/00005537-199906000-00026.

22. Лысенков Н.К., Бушкович В.И., Привес М.Г. Учебник нормальной анатомии человека. – М.: Медгиз; 1958. [Lysenkov NK, Bushkovich VI, Prives MG. Uchebnik normal'noy anatomii cheloveka. Moscow: Medgiz; 1958. (In Russ.)]

23. Соботта Й. Атлас анатомии человека. – М.: Рид Элсивер; 2010. [Sobotta J. Аtlas of human anatomy. Moscow: Reed Elsevier; 2010. (In Russ.)]

24. Роен Й.В., Йокочи Ч., Лютьен-Дреколл Э. Большой атлас по анатомии. – М.: Внешсигма; 1998. [Rohen JW, Yokochi C, Lutjen-Drecoll E. Color Atlas of Anatomy. Moscow: Vneshsigma; 1998. (In Russ.)]

25. Moosman DA, DeWeese MS. The external laryngeal nerve as related to thyroidectomy. Surg Gynecol Obstet. 1968; 127(5):1011-1016.

26. Chuang FJ, Chen JY, Shyu JF, et al. Surgical anatomy of the external branch of the superior laryngeal nerve in Chinese adults and its clinical applications. Head Neck. 2010;32(1): 53-57. doi: https://doi.org/10.1002/hed.21139.

27. Kierner AC, Aigner M, Burian M. The external branch of the superior laryngeal nerve. Arch Otolaryngol Head Neck Surg. 1998;124(3):301. doi: https://doi.org/10.1001/archotol.124.3.301.

28. Poyraz M, Calguner E. Bilateral investigation of the anatomical relationships of the external branch of the superior laryngeal nerve and superior thyroid artery, and also the recurrent laryngeal nerve and inferior thyroid artery. Okajimas Folia Anat Jpn. 2001;78(2-3):65-74. doi: https://doi.org/10.2535/ofaj1936.78.2-3_65.

29. Martin-Oviedo C, Maranillo E, Lowy-Benoliel A, et al. Functional role of human laryngeal nerve connections. Laryngoscope. 2011;121(11):2338-2343. doi: https://doi.org/10.1002/lary.22340.

30. 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):1321-1328. doi: https://doi.org/ 10.1001/archotol.1994.01880360019004.

31. Nasri S, Beizai P, Ye M, et al. Cross-innervation of the thyroarytenoid muscle by a branch from the external division of the superior laryngeal nerve. Ann Otol Rhinol Laryngol. 1997;106(7 Pt 1):594-598. doi: https://doi.org/10.1177/000348949710600712.

32. Maranillo E, Leon X, Quer M, et al. Is the external laryngeal nerve an exclusively motor nerve? The cricothyroid connection branch. Laryngoscope. 2003;113(3):525-529. doi: https://doi.org/10.1097/00005537-200303000-00024.

33. Sun S-Q, Chang RWH. The superior laryngeal nerve loop and its surgical implications. Surg Radiol Anat. 1991;13(3):175-180. doi: https://doi.org/10.1007/bf01627981.

34. Малюга В.Ю., Куприн А.А. Экстраларингеальные варианты расположения возвратного гортанного нерва. Клиническое наблюдение в хирургии щитовидной железы. // Эндокринная хирургия. – 2017. – Т. 11. – №3. – С. 146-156. [Malyuga VY, Kuprin AA. Extralaryngeal variants of the location of the recurrent laryngeal nerve. Clinical observation in thyroid surgery. Endocrine surgery. 2017;11(3):146-156. (In Russ.)] doi: https://doi.org/10.14341/serg20173146-156.

35. Masuoka H, Miyauchi A, Higashiyama T, et al. Prospective randomized study on injury of the external branch of the superior laryngeal nerve during thyroidectomy comparing intraoperative nerve monitoring and a conventional technique. Head Neck. 2015;37(10):1456-1460. doi: https://doi.org/10.1002/hed.23778

Supplementary files

	1. Fig. 1. Scheme. The main skeletotopic landmarks and location options are RENLS. MST is cut, allotted up. a - right side view. PR - pars recta MCT, PO - pars obliqua MCT. The arrows mark the “entrance” of the nerves in the MCPI (three types of RENLS location). Marked angles of nerve direction relative to LO. On MCPI, a triangle is marked with a dotted line, limiting the small space for searching for RENLS. b - front view. I type RENLS. Typical nerve location (in close proximity and parallel to LO). Pinpoint is the penetration point, the “entry point” of the nerve in the MCPI. These structures are noted in most atlases by anatomy [22-24].
	Subject
	Type	Other
	View (212KB)	Indexing metadata ▾

	2. Fig. 2. I type RENLS. Right view. PR - pars recta MCT, PO - pars obliqua MCT. MST, MTH cut off. Marked area of attachment of these muscles - LO. The arrow indicates the “entry point” of the nerve in the MCPI.
	Subject
	Type	Other
	View (169KB)	Indexing metadata ▾

	3. Fig. 3. Type II RENLS. Right view. PR - pars recta MCT, PO - pars obliqua MCT. MST crossed, cast up. The arrow indicates the “entry point” of the nerve in the MCPI. The nerve is located as low as possible from LO (6 mm) and at an angle of 45 degrees to this line.
	Subject
	Type	Other
	View (172KB)	Indexing metadata ▾

	4. Fig. 4. Type III RENLS. Left view. PR - pars recta MCT, PO - pars obliqua MCT. MST, MTH cut off. Marked area of attachment of these muscles - LO. The arrow indicates the “entry point” of the nerve in the MCPI.
	Subject
	Type	Other
	View (161KB)	Indexing metadata ▾

	5. Fig. 5. Syntopy RENLS with the superior thyroid artery. a - right side view, type III (the “arrow” point of the nerve is indicated by a black arrow). The superior thyroid artery is laterally retracted. The white arrow indicates the location of the intersection of the nerve with the branches of the superior thyroid artery. ATS - arteria thyroidea superior, superior thyroid artery (PNA). b - drawing scheme.
	Subject
	Type	Other
	View (249KB)	Indexing metadata ▾

	6. Fig. 6. Additional branches RENLS. Left view. a - the allocated RENLS has two branches: 1 - the main trunk with the “entry point” in the projection of the middle third of LO (type II); 2 - the lower branch, going to the rear surface of the upper pole of the thyroid. b - the thyroid gland share is mobilized, set aside forward and medially. The main trunk RENLS cut off. The lower branch of the nerve is directed to the crico-thyroid connection. NLR is also taken on a ligature holder, retracted anteriorly and medially. Selected lower thyroid artery, forming two branches. The black arrow indicates the location of the “entrance” of the lower RENLS branch in the area of the cricoid-like connection. The white arrows are the “entrance” to the larynx of the two branches of the NLR. ATI - arteria thyroidea inferior, inferior thyroid artery (PNA).
	Subject
	Type	Other
	View (266KB)	Indexing metadata ▾

	7. Fig. 7. Intraoperative picture of the location of RENLS and major anatomical landmarks. and - a bed of the right share (the thyroidectomy is executed). I type RENLS. MSH is crossed on the right. An asterisk denotes a ligated sprig of the superior thyroid artery. b - right side view. I type RENLS. The black arrow marks an additional branch of the nerve heading towards the cricoid joint. The white arrows mark the entry points of the RENLS. Arcus tendineus looks like a whitish arcuate retraction zone between MCPI and MCT.
	Subject
	Type	Other
	View (300KB)	Indexing metadata ▾

	8. Fig. 8. Extraralaryngal plexus. Non-classical anatomical picture. a - cadaveric neck organocomplex with microdissection performed. b - drawing scheme. 1, 2, 3, 4 - the system of anastomoses. ATI - arteria thyroidea inferior, inferior thyroid artery.
	Subject
	Type	Other
	View (294KB)	Indexing metadata ▾

Review

For citations:

Malyuga V.Y., Kuprin A.A. Anatomical landmarks of the external branch of the superior laryngeal nerve. Endocrine Surgery. 2018;12(4):161-177. (In Russ.)

This work is licensed under a Creative Commons Attribution 4.0 License.

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	Title	Fig. 1. Scheme. The main skeletotopic landmarks and location options are RENLS. MST is cut, allotted up. a - right side view. PR - pars recta MCT, PO - pars obliqua MCT. The arrows mark the “entrance” of the nerves in the MCPI (three types of RENLS location). Marked angles of nerve direction relative to LO. On MCPI, a triangle is marked with a dotted line, limiting the small space for searching for RENLS. b - front view. I type RENLS. Typical nerve location (in close proximity and parallel to LO). Pinpoint is the penetration point, the “entry point” of the nerve in the MCPI. These structures are noted in most atlases by anatomy [22-24].
	Date	2019-01-10

	Title	Fig. 2. I type RENLS. Right view. PR - pars recta MCT, PO - pars obliqua MCT. MST, MTH cut off. Marked area of attachment of these muscles - LO. The arrow indicates the “entry point” of the nerve in the MCPI.
	Date	2019-01-10

	Title	Fig. 3. Type II RENLS. Right view. PR - pars recta MCT, PO - pars obliqua MCT. MST crossed, cast up. The arrow indicates the “entry point” of the nerve in the MCPI. The nerve is located as low as possible from LO (6 mm) and at an angle of 45 degrees to this line.
	Date	2019-01-10

	Title	Fig. 4. Type III RENLS. Left view. PR - pars recta MCT, PO - pars obliqua MCT. MST, MTH cut off. Marked area of attachment of these muscles - LO. The arrow indicates the “entry point” of the nerve in the MCPI.
	Date	2019-01-10

	Title	Fig. 5. Syntopy RENLS with the superior thyroid artery. a - right side view, type III (the “arrow” point of the nerve is indicated by a black arrow). The superior thyroid artery is laterally retracted. The white arrow indicates the location of the intersection of the nerve with the branches of the superior thyroid artery. ATS - arteria thyroidea superior, superior thyroid artery (PNA). b - drawing scheme.
	Date	2019-01-10

	Title	Fig. 6. Additional branches RENLS. Left view. a - the allocated RENLS has two branches: 1 - the main trunk with the “entry point” in the projection of the middle third of LO (type II); 2 - the lower branch, going to the rear surface of the upper pole of the thyroid. b - the thyroid gland share is mobilized, set aside forward and medially. The main trunk RENLS cut off. The lower branch of the nerve is directed to the crico-thyroid connection. NLR is also taken on a ligature holder, retracted anteriorly and medially. Selected lower thyroid artery, forming two branches. The black arrow indicates the location of the “entrance” of the lower RENLS branch in the area of the cricoid-like connection. The white arrows are the “entrance” to the larynx of the two branches of the NLR. ATI - arteria thyroidea inferior, inferior thyroid artery (PNA).
	Date	2019-01-10

	Title	Fig. 7. Intraoperative picture of the location of RENLS and major anatomical landmarks. and - a bed of the right share (the thyroidectomy is executed). I type RENLS. MSH is crossed on the right. An asterisk denotes a ligated sprig of the superior thyroid artery. b - right side view. I type RENLS. The black arrow marks an additional branch of the nerve heading towards the cricoid joint. The white arrows mark the entry points of the RENLS. Arcus tendineus looks like a whitish arcuate retraction zone between MCPI and MCT.
	Date	2019-01-10

	Title	Fig. 8. Extraralaryngal plexus. Non-classical anatomical picture. a - cadaveric neck organocomplex with microdissection performed. b - drawing scheme. 1, 2, 3, 4 - the system of anastomoses. ATI - arteria thyroidea inferior, inferior thyroid artery.
	Date	2019-01-10

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Endocrine Surgery

Anatomical landmarks of the external branch of the superior laryngeal nerve

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