Abnormal distance of the extralaryngeal bifurcation point of the recurrent laryngeal nerve from the cricothyroid joint

Abnormal distance of the extralaryngeal bifurcation point of the recurrent laryngeal nerve from... The extralaryngeal bifurcation point of the recurrent laryngeal nerve (RLN) is typically located in a mean distance of 0–2cm from the cricothyroid joint (CTJ). In the presented case though, the left RLN was unexpectedly identified bifurcating in a mean distance of 7 cm from the left CTJ in a young woman with multinodular goiter during total thyroidectomy. The RLN was carefully exposed throughout its course for the avoidance of iatrogenic injury of the nerval structure. The operation was uneventful. The present manuscript aims to highlight a scarce anatomic variation and its implications for thyroidectomy. Rare anatomic variations of the RLN such as the presented one encumber thyroid surgery and represent a severe risk factor of RLN injury. Meticulous operative technique combined with surgeons’ perpetual awareness concerning this peculiar ana- tomical aberration leads to an injury-free thyroid surgery. bifurcating in a mean distance of 7 cm from the cricothyroid INTRODUCTION joint (CTJ). The present manuscript aims to underline a peculiar Identification and preservation of the recurrent laryngeal nerve anatomic variation and its implications for thyroidectomy. (RLN) and its branches during thyroidectomy is a step of para- mount clinical significance [1]. Anatomic variations of the RLN represent a major risk factor of RLN injury [2]. Although current CASE REPORT monitoring procedures reduce the potentiality of accidental injury, direct visual detection of the RLN remains the gold A 33-year-old Caucasian female was operated to our institution standard in thyroidectomy [3]. In the presented case, the left for resistant to medication multinodular goiter. Upon admis- RLN was incidentally detected during total thyroidectomy, sion the patient had palpable thyroid nodules. The patient had Received: October 27, 2017. Accepted: December 18, 2017 Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author(s) 2018. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx257/4812592 by Ed 'DeepDyve' Gillespie user on 16 March 2018 2 T. Piperos et al. nor hoarseness neither discernible cervical lymph nodes. Blood unexpectedly identified that the extralaryngeal bifurcation tests including TSH, T3 and T4 were in the normal spectrum. point (ELBP) of the left RLN was located at a mean distance of An ultrasound scan detected tumescent masses on the surface 7 cm from the left CTJ (Fig. 1). Such an anatomic variation may of both thyroid lobes. Following these, total thyroidectomy was augment the probability of the RLN injury or of its branches. finally scheduled. Subsequently, identification of the RLN at a single point is not A standard thyroid collar incision of ~6 cm was made, suffice for safe thyroidectomy. Then, surgeons exposed the 1–2 cm above the sternal notch and was extended over the right RLN which was detected as in common, in the right tra- sternocleidomastoid muscles. At first, the middle thyroid vein cheoesophageal groove, medially to the common carotid artery, was ligated and the superior poles were mobilized. Both the branching within the proximal 1–2 cm of the CTJ. carotid artery and the jugular vein were gently retracted. Thyroidectomy continued in usual fashion and was unevent- Surgeons performed gradual dissection along with the tra- ful. The patient was discharged the second postoperative day, cheoesophageal groove until the RLN’s entry in the larynx and when the drainage placed was removed. At the follow-up, the 10th postoperative day, the patient had none complication. DISCUSSION The RLN is a branch of the vagus nerve (CN: X) that arises in the inferior neck and carries sensory, motor and parasympathetic fibers to the intrinsic muscles of the larynx apart from the crico- thyroid muscle [4]. The main trunk of the RLN divides in order its terminal branches to innervate their respective muscles. This branching may occur within the larynx or extralaryngeally [5, 6]. The extralaryngeal branching (ELB) of RLN is a common ana- tomic variation that poses an increased potentiality of surgical morbidity in thyroid surgery [2]. In fact, the prevalence of ELB is 60% and this variation is symmetrical in 36.5% of individuals [1]. Its prevalence has no differences in geographic or sex-based subgroups [1]. The most common pattern of RLN extralaryngeal division is bifurcation, as in the presented case, with an incidence of 51% [1]. However, extralaryngeal trifurcation or multiple branches may also occur [1, 2, 5]. When the RLN bifurcates extralangyn- geally, the motor branch is the anterior one and the sensory branch runs posterior and medial [5]. The ELBP is typically located in a mean distance of 0–1 cm, or 1–2 cm from the CTJ [1, 5]. Nevertheless in some cases, the ELBP was located at 3.1–4 cm away from the CTJ, with incidence 1.3% [5]. Surprisingly though, in the presented case, the left RLN bifurcated within the proximal 7 cm of the left CTJ. Specific classification systems aim to present probable ELB anatomic variations, but still it seems that they are not all yet elucidated [1]. Subsequently, when performing thyroid surgery it is essential to expose meticulously the main trunk of RLN and the course of its extralaryngeal branches [7]. This surgical step is of vital significance, since the majority of intraoperative RLN injuries result from failure to recognize all the nerval structures [8]. In particular, when surgeons perform the capsular dissec- tion to thyroidectomy, it is possible that the posterior branch could be presumed as the sole branch of RLN. Herein, the anter- ior branch is susceptible to injury that may lead to vocal cord palsy [1, 8]. Due to the extended distance of the ELBP from the CTJ, as in the presented case, the probability of RLN iatrogenic injury is even higher. The identification of the RLN and of its external branches is potential by the utilization of current intraoperative monitoring devices (IONM). However, such procedures are only an adjunct to the visual nerve identification that remains the gold stand- ard in thyroid surgery [3, 8]. Hereby, the use of several anatomic landmarks, such as the Berry’s ligament, the tracheoesophageal groove and the inferior thyroid artery may guide surgeons to the detection of RLN [1, 5]. Unfortunately though, the relation between RLN and these Figure 1: Extralaryngeal division of the left RLN was incidentally located at a mean distance of 7 cm from the left CTJ. structures may not be helpful in case of a large goiter, Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx257/4812592 by Ed 'DeepDyve' Gillespie user on 16 March 2018 Abnormal distance of the extralaryngeal bifurcation point of the recurrent laryngeal nerve 3 inflammation, extended edema or of anatomic variation, as in recurrent laryngeal nerve: a meta-analysis of 28,387 nerves. the presented case [1, 2]. Langenbecks Arch Surg 2016;401:913–23. Iatrogenic injury of the RLN is a severe postoperative com- 2. Shao T, Qiu W, Yang W. Anatomical variations of the recur- plication in thyroid surgery that can lead to RLN palsy with rent laryngeal nerve in Chinese patients: a prospective symptoms ranging from almost indescribable hoarseness to study of 2,404 patients. Sci. Rep 2016;6:25475. stridor or even acute airway obstruction, in case of bilateral 3. Page C, Monet P, Peltier J, Bonnaire B, Strunski V. Non- RLN accidental damage [9, 10]. recurrent laryngeal nerve related to thyroid surgery: report The incidence of temporary paresis of RLN is ranging from of three cases. J Laryngol Otol 2008;122:757–61. 0.4 to 7.2% and from 0 to 5.2% to permanent nerve paralysis [8]. 4. Moore KL, Dalley AF, Agur AM. Clinically Oriented Anatomy. Therefore, it is reasonable that RLN injury remains a common 7th edn. Philadelphia: Lippincott Williams & Wilkins, 2014. cause of litigation in thyroid surgery [8]. 5. Asgharpour E, Maranillo E, Sañudo J, Pascual-Font A, Hence, fundamentals to avoid RLN iatrogenic injury are: Rodriguez-Niedenfurh M, Valderrama FJ, et al. Recurrent (i) exposure of the RLN and of its extralaryngeal branches through- laryngeal nerve landmarks revisited. Head Neck 2012;34: out their course, since it is quite evident that probable novel ana- 1240–6. tomic variations of the RLN may be unexpectedly detected during 6. Schweizer V, Dörfl J. The anatomy of the inferior laryngeal the operation (ii) good haemostasis and (iii) use of IONM when the nerve. Clin Otolaryngol Allied Sci 1997;22:362–9. intraoperative nerve identification is difficult. 7. Hisham AN, Lukman MR. Recurrent laryngeal nerve in thy- In conclusion, even an anatomic variation of minor degree roid surgery: a critical appraisal. ANZ J Surg 2002;72:887–9. may affect the outcome of thyroidectomy. Subsequently, sur- 8. Barczynski M, Konturek A, Pragacz K, Papier A, Stopa M, geons’ deep knowledge in addition to meticulous operative tech- Nowak W. Intraoperative nerve monitoring can reduce nique are the cornerstone for an injury-free thyroid surgery. prevalence of recurrent laryngeal nerve injury in thyroid reoperations: results of a retrospective cohort study. World J Surg 2014;38:599–606. CONFLICT OF INTEREST STATEMENT 9. Erbil Y, Barbaros U, Issever ¸ H, Borucu I, Salmaslioglu ˘ A, None declared. Mete O, et al. Predictive factors for recurrent laryngeal nerve palsy and hypoparathyroidism after thyroid surgery. Clin Otolaryngol 2007;32:32–7. REFERENCES 10. Jeannon JP, Orabi AA, Bruch GA, Abdalsalam HA, Simo R. 1. Henry BM, Vikse J, Graves JM, Sanna S, Sanna B, Diagnosis of recurrent laryngeal nerve palsy after thyroi- Tomaszewska IM, et al. Extralaryngeal branching of the dectomy: a systematic review. Int J Clin Pract 2009;63:624–9. Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx257/4812592 by Ed 'DeepDyve' Gillespie user on 16 March 2018 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Surgical Case Reports Oxford University Press

Abnormal distance of the extralaryngeal bifurcation point of the recurrent laryngeal nerve from the cricothyroid joint

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Abstract

The extralaryngeal bifurcation point of the recurrent laryngeal nerve (RLN) is typically located in a mean distance of 0–2cm from the cricothyroid joint (CTJ). In the presented case though, the left RLN was unexpectedly identified bifurcating in a mean distance of 7 cm from the left CTJ in a young woman with multinodular goiter during total thyroidectomy. The RLN was carefully exposed throughout its course for the avoidance of iatrogenic injury of the nerval structure. The operation was uneventful. The present manuscript aims to highlight a scarce anatomic variation and its implications for thyroidectomy. Rare anatomic variations of the RLN such as the presented one encumber thyroid surgery and represent a severe risk factor of RLN injury. Meticulous operative technique combined with surgeons’ perpetual awareness concerning this peculiar ana- tomical aberration leads to an injury-free thyroid surgery. bifurcating in a mean distance of 7 cm from the cricothyroid INTRODUCTION joint (CTJ). The present manuscript aims to underline a peculiar Identification and preservation of the recurrent laryngeal nerve anatomic variation and its implications for thyroidectomy. (RLN) and its branches during thyroidectomy is a step of para- mount clinical significance [1]. Anatomic variations of the RLN represent a major risk factor of RLN injury [2]. Although current CASE REPORT monitoring procedures reduce the potentiality of accidental injury, direct visual detection of the RLN remains the gold A 33-year-old Caucasian female was operated to our institution standard in thyroidectomy [3]. In the presented case, the left for resistant to medication multinodular goiter. Upon admis- RLN was incidentally detected during total thyroidectomy, sion the patient had palpable thyroid nodules. The patient had Received: October 27, 2017. Accepted: December 18, 2017 Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author(s) 2018. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx257/4812592 by Ed 'DeepDyve' Gillespie user on 16 March 2018 2 T. Piperos et al. nor hoarseness neither discernible cervical lymph nodes. Blood unexpectedly identified that the extralaryngeal bifurcation tests including TSH, T3 and T4 were in the normal spectrum. point (ELBP) of the left RLN was located at a mean distance of An ultrasound scan detected tumescent masses on the surface 7 cm from the left CTJ (Fig. 1). Such an anatomic variation may of both thyroid lobes. Following these, total thyroidectomy was augment the probability of the RLN injury or of its branches. finally scheduled. Subsequently, identification of the RLN at a single point is not A standard thyroid collar incision of ~6 cm was made, suffice for safe thyroidectomy. Then, surgeons exposed the 1–2 cm above the sternal notch and was extended over the right RLN which was detected as in common, in the right tra- sternocleidomastoid muscles. At first, the middle thyroid vein cheoesophageal groove, medially to the common carotid artery, was ligated and the superior poles were mobilized. Both the branching within the proximal 1–2 cm of the CTJ. carotid artery and the jugular vein were gently retracted. Thyroidectomy continued in usual fashion and was unevent- Surgeons performed gradual dissection along with the tra- ful. The patient was discharged the second postoperative day, cheoesophageal groove until the RLN’s entry in the larynx and when the drainage placed was removed. At the follow-up, the 10th postoperative day, the patient had none complication. DISCUSSION The RLN is a branch of the vagus nerve (CN: X) that arises in the inferior neck and carries sensory, motor and parasympathetic fibers to the intrinsic muscles of the larynx apart from the crico- thyroid muscle [4]. The main trunk of the RLN divides in order its terminal branches to innervate their respective muscles. This branching may occur within the larynx or extralaryngeally [5, 6]. The extralaryngeal branching (ELB) of RLN is a common ana- tomic variation that poses an increased potentiality of surgical morbidity in thyroid surgery [2]. In fact, the prevalence of ELB is 60% and this variation is symmetrical in 36.5% of individuals [1]. Its prevalence has no differences in geographic or sex-based subgroups [1]. The most common pattern of RLN extralaryngeal division is bifurcation, as in the presented case, with an incidence of 51% [1]. However, extralaryngeal trifurcation or multiple branches may also occur [1, 2, 5]. When the RLN bifurcates extralangyn- geally, the motor branch is the anterior one and the sensory branch runs posterior and medial [5]. The ELBP is typically located in a mean distance of 0–1 cm, or 1–2 cm from the CTJ [1, 5]. Nevertheless in some cases, the ELBP was located at 3.1–4 cm away from the CTJ, with incidence 1.3% [5]. Surprisingly though, in the presented case, the left RLN bifurcated within the proximal 7 cm of the left CTJ. Specific classification systems aim to present probable ELB anatomic variations, but still it seems that they are not all yet elucidated [1]. Subsequently, when performing thyroid surgery it is essential to expose meticulously the main trunk of RLN and the course of its extralaryngeal branches [7]. This surgical step is of vital significance, since the majority of intraoperative RLN injuries result from failure to recognize all the nerval structures [8]. In particular, when surgeons perform the capsular dissec- tion to thyroidectomy, it is possible that the posterior branch could be presumed as the sole branch of RLN. Herein, the anter- ior branch is susceptible to injury that may lead to vocal cord palsy [1, 8]. Due to the extended distance of the ELBP from the CTJ, as in the presented case, the probability of RLN iatrogenic injury is even higher. The identification of the RLN and of its external branches is potential by the utilization of current intraoperative monitoring devices (IONM). However, such procedures are only an adjunct to the visual nerve identification that remains the gold stand- ard in thyroid surgery [3, 8]. Hereby, the use of several anatomic landmarks, such as the Berry’s ligament, the tracheoesophageal groove and the inferior thyroid artery may guide surgeons to the detection of RLN [1, 5]. Unfortunately though, the relation between RLN and these Figure 1: Extralaryngeal division of the left RLN was incidentally located at a mean distance of 7 cm from the left CTJ. structures may not be helpful in case of a large goiter, Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx257/4812592 by Ed 'DeepDyve' Gillespie user on 16 March 2018 Abnormal distance of the extralaryngeal bifurcation point of the recurrent laryngeal nerve 3 inflammation, extended edema or of anatomic variation, as in recurrent laryngeal nerve: a meta-analysis of 28,387 nerves. the presented case [1, 2]. Langenbecks Arch Surg 2016;401:913–23. Iatrogenic injury of the RLN is a severe postoperative com- 2. Shao T, Qiu W, Yang W. Anatomical variations of the recur- plication in thyroid surgery that can lead to RLN palsy with rent laryngeal nerve in Chinese patients: a prospective symptoms ranging from almost indescribable hoarseness to study of 2,404 patients. Sci. Rep 2016;6:25475. stridor or even acute airway obstruction, in case of bilateral 3. Page C, Monet P, Peltier J, Bonnaire B, Strunski V. Non- RLN accidental damage [9, 10]. recurrent laryngeal nerve related to thyroid surgery: report The incidence of temporary paresis of RLN is ranging from of three cases. J Laryngol Otol 2008;122:757–61. 0.4 to 7.2% and from 0 to 5.2% to permanent nerve paralysis [8]. 4. Moore KL, Dalley AF, Agur AM. Clinically Oriented Anatomy. Therefore, it is reasonable that RLN injury remains a common 7th edn. Philadelphia: Lippincott Williams & Wilkins, 2014. cause of litigation in thyroid surgery [8]. 5. Asgharpour E, Maranillo E, Sañudo J, Pascual-Font A, Hence, fundamentals to avoid RLN iatrogenic injury are: Rodriguez-Niedenfurh M, Valderrama FJ, et al. Recurrent (i) exposure of the RLN and of its extralaryngeal branches through- laryngeal nerve landmarks revisited. Head Neck 2012;34: out their course, since it is quite evident that probable novel ana- 1240–6. tomic variations of the RLN may be unexpectedly detected during 6. Schweizer V, Dörfl J. The anatomy of the inferior laryngeal the operation (ii) good haemostasis and (iii) use of IONM when the nerve. Clin Otolaryngol Allied Sci 1997;22:362–9. intraoperative nerve identification is difficult. 7. Hisham AN, Lukman MR. Recurrent laryngeal nerve in thy- In conclusion, even an anatomic variation of minor degree roid surgery: a critical appraisal. ANZ J Surg 2002;72:887–9. may affect the outcome of thyroidectomy. Subsequently, sur- 8. Barczynski M, Konturek A, Pragacz K, Papier A, Stopa M, geons’ deep knowledge in addition to meticulous operative tech- Nowak W. Intraoperative nerve monitoring can reduce nique are the cornerstone for an injury-free thyroid surgery. prevalence of recurrent laryngeal nerve injury in thyroid reoperations: results of a retrospective cohort study. World J Surg 2014;38:599–606. CONFLICT OF INTEREST STATEMENT 9. Erbil Y, Barbaros U, Issever ¸ H, Borucu I, Salmaslioglu ˘ A, None declared. Mete O, et al. Predictive factors for recurrent laryngeal nerve palsy and hypoparathyroidism after thyroid surgery. Clin Otolaryngol 2007;32:32–7. REFERENCES 10. Jeannon JP, Orabi AA, Bruch GA, Abdalsalam HA, Simo R. 1. Henry BM, Vikse J, Graves JM, Sanna S, Sanna B, Diagnosis of recurrent laryngeal nerve palsy after thyroi- Tomaszewska IM, et al. Extralaryngeal branching of the dectomy: a systematic review. Int J Clin Pract 2009;63:624–9. Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx257/4812592 by Ed 'DeepDyve' Gillespie user on 16 March 2018

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Published: Jan 1, 2018

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