scholarly journals VIRIATION OF THE EXTERNAL BRANCH OF THE SUPERIOR LARYNGEAL NERVE

2019 ◽  
Vol 21 (1) ◽  
pp. 84-88
Author(s):  
V Y Malyuga ◽  
A A Kuprin
Keyword(s):  
Thyroid Gland ◽  
Thyroid Cartilage ◽  
Oblique Line ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Type I ◽  
Constrictor Muscle ◽  
Point Of Entry ◽  
External Branch ◽  
Inferior Pharyngeal Constrictor

Till now, there is no universal clinical classification about variations of the external branch of the superior laryngeal nerve despite the multiple classifications that was proposed. The aim of this research is identification and systematization of topographic types of the external branch of the superior laryngeal nerve. 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 identify two permanent landmark that are located at the minimum distance from nerve and on which we made metrical calculations: oblique line of thyroid cartilage, tendinous arch of the inferior pharyngeal constrictor muscle. The “entry” point of the nerve is always located on the inferior pharyngeal constrictor muscle,and not protruding beyond the oblique line of thyroid cartilage superiorly and tendinous arch of the inferior pharyngeal constrictor muscle anteriorly. The proposed topographic classification of the location of the external branch of the superior laryngeal nerve is based on localization of point of pierced of the nerve relating to the length of the oblique line of thyroid cartilage. In 64.2% of cases, the external branch of the superior laryngeal nerve was in close proximity to the upper pole of the thyroid gland, which could lead to its damage during surgery (type I and II). In type III and IV (35.8%) - the point of "entry" in the muscle was located as far as possible from the upper pole of the thyroid gland, and most of the nerve was covered by the fibers of the inferior pharyngeal constrictor muscle.

scholarly journals Anatomical landmarks of the external branch of the superior laryngeal nerve

2019 ◽  
Vol 12 (4) ◽  
pp. 161-177
Author(s):  
Viktor Y. Malyuga ◽  
Aleksandr A. Kuprin
Keyword(s):  
Thyroid Cartilage ◽  
Oblique Line ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Constrictor Muscle ◽  
External Branch ◽  
Close Proximity ◽  
Inferior Pharyngeal Constrictor ◽  
Line Type

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.

scholarly journals Identification and Preservation of External Branch of Superior Laryngeal Nerve in Thyroidectomy

2013 ◽  
Vol 3 (2) ◽  
pp. 39-41 ◽  
Author(s):  
Bhagyashree D Bokare ◽  
Poorva K Athavale ◽  
Vipin R Ekhar ◽  
Devendra Meghraj Mahore
Keyword(s):  
Thyroid Gland ◽  
Total Thyroidectomy ◽  
Superior Laryngeal Nerve ◽  
Vocal Folds ◽  
Laryngeal Nerve ◽  
Superior Thyroid Artery ◽  
Type I ◽  
Care Hospital ◽  
External Branch ◽  
Superior Pole

ABSTRACT The basic principle of head and neck surgery is based on the identification and preservation of important structures, rather than avoidance. This principle is also applicable to identification and preservation of external branch of the superior laryngeal nerve (EBSLN) as a standard routine in all thyroid surgeries. During thyroid surgery, the EBSLN is clearly at risk due to its close proximity to the superior thyroid artery (STA) and its branches that need to be ligated during dissection of the superior pole of the thyroid gland. Injury is detrimental to the patient by causing paralysis of the cricothyroid muscle which is the main tensor and pitch controlling mechanism of the vocal folds. Injury to the EBSLN during surgery can result in the voice changes, loss of upper range and easy fatigability of voice, the severity of which varies according to the vocal demand of the patient. Total 45 cases of thyroid swellings were treated with surgery, in the Department of ENT at a tertiary care hospital during the period from 1st October 2009 to 30th October 2010. Hemithyroidectomy was the most common operative procedure implemented in 24 patients (53.33%) in which right sided was common. Next common procedure performed was that of total thyroidectomy in 14 patients (31.11%). Four patients underwent total thyroidectomy with neck dissection. The position of EBSLN was classified according the Cernea et al classification. In our study we found the EBSLN to be type I in 46.66%, type IIa in 73.33% and type IIb in 02.22%. The anatomical landmark taken into consideration to identify EBSLN was the Joll's triangle with its relation to the superior pole of the thyroid gland and STA. How to cite this article Athavale PK, Bokare BD, Ekhar VR, Mahore DM. Identification and Preservation of External Branch of Superior Laryngeal Nerve in Thyroidectomy. Int J Phonosurg Laryngol 2013;3(2):39-41.

scholarly journals Assessment of Relation between External Branch of Superior Laryngeal Nerve & Thyroid Gland- A Cadaveric Study

2020 ◽  
Vol 6 (2) ◽  
pp. 73-76
Author(s):  
Anurag ◽  
Vishnu Gupta
Keyword(s):  
Thyroid Gland ◽  
Cricoid Cartilage ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
The Body ◽  
Superior Thyroid Artery ◽  
Group I ◽  
External Branch ◽  
The Mean ◽  
Group Ii

Background: The thyroid gland is essential for normal growth of the body. This study assessed relation of external branch of superior laryngeal nerve to the superior pole of the thyroid gland. Subjects and Methods: This study was conducted on 25 human cadavers having 50 superior thyroid poles of both genders. Cadavers were classified based on age groups, group I was those with age less than 39 years and group II cadavers were those with age more than 40 years of age. Various measurements were performed on cadavers. Results: 14 cadavers were I group I and 11 were in group II. The mean mass was 67.2 Kgs in group I and 59.5 Kgs in group II, time elapsed after death was 481.5 minutes in group I and 476.4 minutes in group II, mean height was 1.74 meters in group I and 1.69 meters in group II, mean BMI found to be 22.3 kg/m2in group I and 20.1 kg/m2in group II. Height found to be significant between both groups (P< 0.05). The mean distance from EBSLN to cranial point of the thyroid gland was 6.66 mm in group I and 8.96 mm in group II. The mean transverse distance from superior thyroid artery to EBSLN was 3.55 mm in group I and 5.12 mm side in group II. The mean distance of the crossing point between the most cranial point of the thyroid lobe was 6.40 mm in group I and 11.47 mm in group II. The mean distance from the EBSLN to the midline of the neck was 19.80 mm in group I and 18.58 mm in group II. The mean distance from the EBSLN to the midline of the neck on the most cranial point of the cricoid cartilage was 18.77 mm in group I and 17.80 mm in group II. Conclusion: Authors found variation in measurements in left and right side in both group I and group II.

Identification and preservation of External Branch of the Superior Laryngeal Nerve during thyroid surgeries at NMCTH

2017 ◽  
Vol 13 (3) ◽  
pp. 306-310 ◽  
Author(s):  
Rupesh Raj Joshi ◽  
Anupama Shah Rijal ◽  
Kundhan Kumar Shrestha ◽  
Anup Dhungana ◽  
Shova Maharjan
Keyword(s):  
Case Series ◽  
Superior Laryngeal Nerve ◽  
Thyroid Neoplasms ◽  
Laryngeal Nerve ◽  
Type I ◽  
Tertiary Centre ◽  
External Branch ◽  
Common Diagnosis ◽  
Recurrent Laryngeal Nerves ◽  
Nerve Identification

Background & Objectives:The most common reason for thyroid surgery is the presence of benign or malignant nodules. Subjective voice disturbance after thyroidectomy is very common, even without injury to the recurrent laryngeal nerves. One possible cause for postoperative dysphonia is injury to the External branch of superior laryngeal nerve (EBSLN). Cernea classification, which we followed in this study, is one of the most popular worldwide classifications of the EBSLN. The study was conducted with objectives to identify and classify EBSLN according to Cernia classification in Nepalese population and help surgeons understand the anatomy of the EBSLN and to preserve the nerve during thyroidectomy. Materials & Methods:A prospective observational case series of seventy-nine patients, who were diagnosed with thyroid neoplasms and underwent thyroid surgeries at the tertiary centre of Kathmandu between 1st January 2015 to 31st December 2016. All procedures were performed by transverse collar incision. We classified the anatomy of the EBSLN using Cernea classification.  Results:There were total of 79 patients. Most common diagnosis and surgery were colloid goitre and hemithyroidectomies respectively. A total of 94 EBSLNs were evaluated.  Cernia Type I was observed in 27.66%, type IIa in 46.80%, and type IIb in 14.89%. Incidences of types IIa and IIb, which put patients at greater risk for intra-operative injury, were observed in 61.69% in our study. The nerve could not be identified in 10.64%. Conclusion:It is possible to increase the rate of nerve identification and avoid the nerve injury even in the absence of sophisticated equipment.

Study of Some “Intrinsic Risk Factors” that Can Enhance an Iatrogenic Injury of the External Branch of the Superior Laryngeal Nerve

2003 ◽  
Vol 128 (3) ◽  
pp. 396-400 ◽  
Author(s):  
Julio Cesar Furlan ◽  
Anói Castro Cordeiro ◽  
Lenine Garcia Brandã
Keyword(s):  
Risk Factors ◽  
Thyroid Gland ◽  
Analysis Of Variance ◽  
Study Design ◽  
Statistical Significance ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Human Adult ◽  
External Branch ◽  
Anatomic Relationship

OBJECTIVE: This study evaluates some “intrinsic risk factors” for a surgical injury of the external branch of superior laryngeal nerve (EBSLN) based on its anatomic relationship with the thyroid gland. STUDY DESIGN AND SETTING: Seventy-two neck dissections were performed in 36 fresh human adult cadavers. Every EBSLN was dissected and categorized using Cernea's classification. All data regarding gender, ethnicity, stature, side of the neck, and volume of hemi thyroid were collected and statistically analyzed by the χ 2 –test and analysis of variance. RESULTS: Although no statistical differences were observed between genders ( P = 0.3770), ethnicities ( P = 0.9780) or sides of the neck ( P = 0.2523), statistical significance was reached regarding the nerve type when the groups were divided by stature ( P = 0.0006) and glandular volume ( P = 0.0007). CONCLUSION: Individual stature and volume of the hemi thyroid gland are probably involved in risk of the surgical EBSLN injury. SIGNIFICANCE: Surgeons should be aware of these anatomic findings in order to obtain a good voice-related outcome in the thyroidectomies.

scholarly journals Relation of the external branch of the superior laryngeal nerve to the superior pole of the thyroid gland: An anatomical study

2007 ◽  
Vol 20 (5) ◽  
pp. 516-520 ◽  
Author(s):  
D. Naidoo ◽  
J.M. Boon ◽  
C.J. Mieny ◽  
P.J. Becker ◽  
A.-N. van Schoor
Keyword(s):  
Thyroid Gland ◽  
Superior Laryngeal Nerve ◽  
Anatomical Study ◽  
Laryngeal Nerve ◽  
External Branch ◽  
Superior Pole

scholarly journals Protection of the external branch of the superior laryngeal nerve in Transoral endoscopic thyroidectomy vestibular approach (TOETVA): an observational study

2021 ◽  
Author(s):  
Zhen Wu ◽  
Jugao Fang ◽  
Hongzhi Ma ◽  
Xiao Chen ◽  
Qi Zhong ◽  
...  
Keyword(s):  
Contractile Activity ◽  
Endoscopic Thyroidectomy ◽  
Thyroid Cartilage ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
External Branch ◽  
Protective Strategies ◽  
The Right ◽  
Intraoperative Nerve Monitoring ◽  
Vestibular Approach

Abstract Background: Avoiding injury of the external branch of the superior laryngeal nerve（EBSLN） is one of the major challenges during thyroid surgery, especially in transoral endoscopic thyroidectomy vestibular approach (TOETVA). This study aimed to investigate the protective strategies of the EBSLN during TOETVA. Methods: In order to protect the EBSLN during TOETVA, we adopted the method of identification the nerve by anatomy and localization. The method of anatomy involves the dissection of EBSLN by complete transection of the sternothyroid muscle in the attachment of the thyroid cartilage. The method of localization involves nerve stimulation localization, which produces cricothyroid contractile activity through intraoperative nerve monitoring stimulation (IONM). Concurrently, patients were evaluated preoperatively and at 1 and 3 weeks postoperatively in an individual prospective cohort study using a stroboscopic laryngoscope and the voice handicap index-10 (VHI-10). The VHI-10 score was used to evaluate voice changes. Results: We retrospectively analyzed patients with papillary thyroid cancer (PTC) who underwent TOETVA in the thyroid center of the Beijing Tongren hospital between February 2018 and June 2020. Patients with recurrent laryngeal nerve（RLN）damage were excluded. Sixty patients were enrolled in this study, of which four underwent total thyroidectomy. Intraoperatively, 56 EBSLNs were located (56/64, 87.50%). Among these, the left EBSLN was identified in 20/25(80.00%) and the right EBSLN was identified in 36/39 (92.31%) cases. One week postoperatively, a blinded stroboscopic laryngoscope examination showed that no patient had paresis of the EBSLN. However, the VHI-10 score was significantly higher than the preoperative value (10.58 ± 4.54 vs. 3.00 ± 1.54, p＜0.01). At three weeks postoperatively, the overall score was still different from that preoperatively (4.83 ± 3.34 vs. 3.00 ± 1.54, p＜0.01); however, the vast majority of patients returned to their preoperative status. Conclusion: In TOETVA, the EBSLN can be well exposed by transection of the sternothyroid muscle, and combined with IONM, the protection of the function of the EBSLN can be guaranteed. Simultaneously, we observed that TOETVA could cause a short-term voice handicap in patients, with such changes generally returning to normal within three weeks.

The Anatomical and Clinical Significance of the Superior Laryngeal Nerve

2021 ◽  
pp. 019459982198962
Author(s):  
Kai-ning Lu ◽  
Jin-wang Ding ◽  
Yu Zhang ◽  
Jing-jing Shi ◽  
Li Zhou ◽  
...  
Keyword(s):  
Thyroid Cartilage ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Entry Point ◽  
Horizontal Line ◽  
Lower Edge ◽  
External Branch ◽  
Starting Point ◽  
Human Cadavers ◽  
Medical University

Objective This study summarizes the anatomical features of the superior laryngeal nerve in Chinese to enable the rapid location of the superior laryngeal nerve during an operation. Study Design Retrospective analysis of anatomical data. Setting Hangzhou First People’s Hospital Affiliated to Nanjing Medical University. Methods A total of 71 embalmed human cadavers (132 heminecks) were examined over 3 months. The length and diameter of the internal and external branches of the superior laryngeal nerve and their relationships with different landmarks were recorded. Results The total length of the internal branch of the superior laryngeal nerve was 23.4 ± 6.9 mm. The length of the external branch of the superior laryngeal nerve was 47.7 ± 11.0 mm. Considering the midpoint of the lower edge of the thyroid cartilage as the starting point and using that edge as a horizontal line, when the entry point is above that line, the external branch of the superior laryngeal nerve can be found within 41.1 mm and at an angle of 57.2°. When the entry point is below the lower edge of the thyroid cartilage, the external branch of the superior laryngeal nerve can be found within 34.0 mm and at an angle of 36.5°. Conclusion The superior laryngeal nerve in Chinese people has distinct anatomical characteristics. This article provides a new method of quickly locating the external branch of the superior laryngeal nerve during the operation, which can reduce the probability of damaging the external branch of the superior laryngeal nerve.

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