Morbidity after thyroidectomy is related to injuries to the parathyroids, recurrent laryngeal (RLN) and external branch of superior laryngeal nerves (EBSLN). Mostly these are due to variations in the surgical anatomy. In this study we analyse the surgical anatomy of the laryngeal nerves in Indian patients undergoing thyroidectomy. Materials and Methods. Retrospective study (February 2008 to February 2010). Patients undergoing surgery for benign goitres, T1, T2 thyroid cancers without lymph node involvement were included. Data on EBSLN types, RLN course and its relation to the TZ & LOB were recorded. Results. 404 thyroid surgeries (180 total & 224 hemithyroidectomy) were performed. Data related to 584 EBSLN and RLN were included (324 right sided & 260 left sided). EBSLN patterns were Type 1 in 71.4%, Type IIA in 12.3%, and Type IIB in 7.36%. The nerve was not seen in 4.3% cases. RLN had one branch in 69.34%, two branches in 29.11% and three branches in 1.36%. 25% of the RLN was superficial to the inferior thyroid artery, 65% deep to it and 8.2% between the branches. TZ was Grade 1 in 65.2%, Grade II in 25.1% and Grade III in 9.5%. 31.16% of the RLN passes through the LOB. Conclusions. A thorough knowledge of the laryngeal nerves and anatomical variations is necessary for safe thyroid surgery. 1. Introduction Thyroid surgery was associated with high mortality rates in the early nineteenth century. The high mortality (20%) was attributed to the lack of meticulous dissection techniques and asepsis [1]. So much so, in the year 1850 the French Academy of Medicine banned thyroid surgery [2]. With the advent of antiseptic techniques and antibiotics the mortality due to sepsis has disappeared. So also, the refinement in surgical techniques, recognition of the presence of parathyroids, RLN, and need to protect the EBSLN resulted in lesser morbidity. Through understanding of the surgical anatomy has been crucial in decreasing the morbidity. Mostly the morbidity is due to technical failure to identify the vital structures and the variations in the surgical anatomy when the gland is pathologically enlarged. Several studies have been published revealing the anatomy of the laryngeal nerves as seen during thyroid surgery [1, 3–5]. Exposure of EBSLN and individual ligation of superior thyroid artery branches in the medial thyroid space was initially stressed to avoid injury to it [1, 6, 7]. Based on the course of the EBSLN; classifications were also put forward by Cernea et al. and Friedman et al. [4, 8]. EBSLN has several branches to pharynx and thyroid gland apart
References
[1]
R. D. Bliss, P. G. Gauger, and L. W. Delbridge, “Surgeon's approach to the thyroid gland: surgical anatomy and the importance of technique,” World Journal of Surgery, vol. 24, no. 8, pp. 891–897, 2000.
[2]
W. W. Greene, “Three cases of bronchocele successfully removed,” American Journal of the Medical Sciences, vol. 121, article 80, 1871.
[3]
E. N. Aina and A. N. Hisham, “External Laryngeal Nerve in thyroid surgery: recognition and surgical implications,” ANZ Journal of Surgery, vol. 71, no. 4, pp. 212–214, 2001.
[4]
C. R. Cernea, A. R. Ferraz, S. Nishio, A. Dutra Jr., F. C. Hojaij, and L. R. M. dos Santos, “Surgical anatomy of the external branch of the superior laryngeal nerve,” Head and Neck, vol. 14, no. 5, pp. 380–383, 1992.
[5]
L. Delbridge, T. S. Reeve, M. Khadra, and A. G. Poole, “Total thyroidectomy: the technique of capsular dissection,” Australian and New Zealand Journal of Surgery, vol. 62, no. 2, pp. 96–99, 1992.
[6]
F. A. Coller and A. M. Boyden, “The development of technique of thyroidectomy: presentation of method used in university hospital,” Surgery, Gynecology & Obstetrics, vol. 65, article 495, 1937.
[7]
D. A. Moosman and M. S. de Weese, “The external laryngeal nerve as related to thyroidectomy,” Surgery Gynecology and Obstetrics, vol. 127, no. 5, pp. 1011–1016, 1968.
[8]
M. Friedman, P. LoSavio, and H. Ibrahim, “Superior laryngeal nerve identification and preservation in thyroidectomy,” Archives of Otolaryngology, vol. 128, no. 3, pp. 296–303, 2002.
[9]
B. Yalacin, R. S. Tubbs, A. Durmaz et al., “Branching pattern of the external branch of the superior laryngeal nerve and its clinical importance,” Clinical Anatomy, vol. 25, no. 1, pp. 32–39, 2012.
[10]
S. Lennquist, C. Cahlin, and S. Smeds, “The superior laryngeal nerve in thyroid surgery,” Surgery, vol. 102, no. 6, pp. 999–1008, 1987.
[11]
J. Visset, J. Leborgne, and J. Y. Barbin, “The external laryngeal nerve,” Bulletin de l'Association des Anatomistes, vol. 59, no. 167, pp. 1001–1012, 1975.
[12]
M. R. Pelizzo, A. Toniato, and G. Gemo, “Zuckerkandl's tuberculum: an arrow pointing to the recurrent laryngeal nerve (constant anatomical landmark),” Journal of the American College of Surgeons, vol. 187, no. 3, pp. 333–336, 1998.
[13]
A. C. Kierner, M. Aigner, and M. Burian, “The external branch of the superior laryngeal nerve: its topographical anatomy as related to surgery of the neck,” Archives of Otolaryngology, vol. 124, no. 3, pp. 301–303, 1998.
[14]
P. Whitfield, R. P. Morton, and S. Al-Ali, “Surgical anatomy of the external branch of the superior laryngeal nerve,” ANZ Journal of Surgery, vol. 80, no. 11, pp. 813–816, 2010.
[15]
S. Ozlugedik, H. I. Acar, N. Apaydin, I. Tekdemir, A. Elhan, and A. Comert, “Surgical anatomy of the external branch of the superior laryngeal nerve,” Clinical Anatomy, vol. 20, no. 4, pp. 387–391, 2007.
[16]
A. Mishra, H. Temadari, N. Singh, S. Mishra, and A. Agarwal, “The external laryngeal nerve in thyroid surgery: rhe “no more neglected” nerve,” Indian Journal of Medical Sciences, vol. 61, no. 1, pp. 3–7, 2007.
[17]
F. Estrela, H. Z. Le？o, and G. P. Jotz, “Anatomic relation between the external branch of the superior laryngeal nerve and the thyroid gland,” Brazilian Journal of Otorhinolaryngology, vol. 77, no. 2, pp. 249–258, 2011.
[18]
E. L. Kaplan, G. I. Salti, M. Roncella, N. Fulton, and M. Kadowaki, “History of the recurrent laryngeal nerve: from Galen to Lahey,” World Journal of Surgery, vol. 33, no. 3, pp. 386–393, 2009.
[19]
C. R. Cernea, F. V. C. Hojaij, D. de Carlucci Jr. et al., “Recurrent laryngeal nerve: a plexus rather than a nerve?” Archives of Otolaryngology, vol. 135, no. 11, pp. 1098–1102, 2009.
[20]
J. W. Serpell, M. J. Yeung, and S. Grodski, “The motor fibers of the recurrent laryngeal nerve are located in the anterior extralaryngeal branch,” Annals of Surgery, vol. 249, no. 4, pp. 648–652, 2009.
[21]
C. Casella, G. Pata, R. Nascimbeni, F. Mittempergher, and B. Salerni, “Does extralaryngeal branching have an impact on the rate of postoperative transient or permanent recurrent laryngeal nerve palsy?” World Journal of Surgery, vol. 33, no. 2, pp. 261–265, 2009.
[22]
N. L. Lekacos, P. J. Tzardis, P. G. Sfikakis, S. D. Patoulis, and S. D. Restos, “Course of the recurrent laryngeal nerve relative to the inferior thyroid artery and the suspensory ligament of Berry,” International Surgery, vol. 77, no. 4, pp. 287–288, 1992.
[23]
D. Berlin, “The recurrent laryngeal nerve in total ablation of the normal thyroid gland,” Surgery, Gynecology & Obstetrics, vol. 60, pp. 19–26, 1935.
[24]
C. K. Leow and A. J. Webb, “The Lateral Thyroid Ligament of Berry,” International Surgery, vol. 83, no. 1, pp. 75–78, 1998.
[25]
T. R. Kumar, P. V. Pradeep, and M. Ragavan, “Bilobar thyroid agenesis presenting with qdenomatous isthmus and hypothyroidism in a 13 year old girl: a case report,” Journal of Pediatric Sciences, vol. 2, no. 2, article e21, 2010.
