The Reliability of the Tracheoesophageal Groove and the Ligament of Berry as Landmarks for Identifying the Recurrent Laryngeal Nerve: A Cadaveric Study and Meta-Analysis

Variations in Recurrent Laryngeal Nerve in Thyroidectomy

The aim of this study was to identify and evaluate variations in anatomy and the course of Recurrent. Laryngeal nerve (RLN) with respect to various landmarks. A retrospective study was conducted in the department of ENT and head and neck surgery in our institute including 52 eu-thyroid cases who had undergone primary thyroid surgery over a period of 1 year. 48 cases underwent hemi-thyroidectomy and 4 had total thyroidectomy. During the surgery the anatomy and relationship to surrounding structures of the RLN that were observed were recorded and compiled among the 56 sides that were operated on, RLN was identified as a single trunk in 47 cases (83.9%). The nerve showed extra-laryngeal branches in 6 cases (10.7%) while 3 cases were found to have degenerated RLN. None of the cases were found with a non-recurrent laryngeal nerve. With respect to inferior thyroid artery (ITA), 82% cases had the nerve passing deep to it and in the rest 18% the nerve passed anterior to the artery. While in none of the cases the nerve passed in between the branches of the artery. With respect to the tracheo-esophageal groove, RLN was found within the groove in 44 cases, while in 12 cases RLN was located lateral to the trachea-oesophageal groove. In the current study, variations in the anatomy of RLN was found less frequently, owing to the comparatively small sample size. The ITA and trachea-esophageal groove were both found as reliable landmarks for tracking the RLN.

Tension-free thyroidectomy (medial thyroidectomy)-a prospective study: surgical technique and results of 259 operations

Background

Thyroid surgery is associated with a number of surgical complications including recurrent laryngeal nerve (RLN) injury and hypoparathyroidism. The existing methods share the same principle-the mobilization of the thyroid from the lateral side. The aim of this study was to evaluate the safety of a novel technique of thyroidectomy-tension-free thyroidectomy (TFT) based on the medial approach to the laryngeal nerves and parathyroid glands (PTGs).

Methods

The study was conducted between August 2021 and July 2022 in Saint Petersburg State University Hospital. A total of 261 patients with thyroid diseases were enrolled in the study and operated on using the TFT technique.

Results

The operations with the use of TFT technique were completed in all but two cases which required the conversion to the standard lateral approach. Of 259 TFT cases unilateral laryngeal paresis was registered in 6 (2.3%) cases or in 1.7% of the number of RLNs at risk. In all but one case the vocal fold function recovered in less than 6 months of the follow-up. Among 87 patients who underwent total thyroidectomy transient postoperative hypoparathyroidism was found in 10 cases (11.5%), rate of persistent hypoparathyroidism was 0%. One case of postoperative bleeding was recorded (0.4%).

Conclusions

The TFT technique demonstrated high safety and several advantages over the traditional method of performing operations on the thyroid gland.

Radiofrequency Ablation for Benign Thyroid Nodules: Radiology In Training

Two patients, one with benign nonfunctioning nodules and one with functioning thyroid nodules, both of whom underwent radiofrequency ablation, are presented. Preprocedural evaluation, procedural considerations, and follow-up care of thyroid radiofrequency ablation, as well as published evidence on the topic, are discussed.

Identification of valid anatomical landmarks to locate and protect recurrent laryngeal nerve during thyroid surgery: a cadaveric study

PURPOSE

Recurrent laryngeal nerve (RLN) is the most critical structure in terms of intricacy. Anatomic variations of the nerve may further make thyroid surgery cumbersome. The present study was undertaken to provide comprehensive knowledge about the soundness of commonly used anatomical landmarks such as Berry's ligament (BL), tracheo-esophageal groove (TEG), inferior thyroid artery (ITA), and the midpoint of the posterior border of the thyroid gland in the identification of the nerve intraoperatively.

METHODS

Thirty adult cadavers were dissected to identify the RLN in the neck and to locate it in relation to the aforementioned anatomical landmarks.

RESULTS

The RLN/BL relationship: RLN was most often located superficial to the BL (88.3%), followed by deep to the BL in 8.4%, and piercing the BL in 3.3% of cases, respectively. The RLN/TEG relationship: the RLN was located inside the TEG in most cases (71.7%), followed by RLN lying outside the TEG in 28.3%. Outside the groove, it was most commonly found lateral to the TEG (64.7%). RLN/ITA relationship: the nerve was passing deep to the artery in most of the cases (65%), followed by superficial (30%) and rarely (5%) in-between the branches. RLN/ midpoint posterior border of thyroid relationship: In 57 (95%) cases, RLN was coursing in the area posterior to the midpoint of the posterior border of the gland with an average distance of 4.95 ± 2.23 mm ranging between 2.21 and 12.1 mm.

CONCLUSIONS

Both the BL and TEG are potentially crucial for safeguarding RLN. Although in results, BL turns out to be more consistent than TEG, we propose the utilization of both these anatomical landmarks together for complication-free neck surgeries. Furthermore, the midpoint of the posterior border of the thyroid turns out to be the single most consistent landmark for identifying RLN during partial thyroidectomy.

Relative Topography of Laryngeal Nerves for Surgical Cruciality: An Observational Cadaveric Study

To observe and evaluate the intricrate relationship of recurrent laryngeal nerve (RLN) and external branch of superior laryngeal nerve (EBSLN) to various anatomical structures in the neck like the inferior thyroid artery (ITA), Berry's ligament (LB), Zuckerkandl's tubercle (ZT) and with the superior thyroid artery (STA) for the knowledge of surgical cruciality during surgeries for thyroid gland diseases. This cadaveric observational study was conducted in the department of Otorhinolaryngology and Head and Neck Surgery with logistic support from Department of Anatomy. Total of 40 fresh frozen latex injected cadavers neck dissection was performed to study anatomical variations of thyroid gland and its related vessels and nerves. All measurements were recorded using digital caliper sensitive to 0.01 mm and photographs were documented. Topography of RLN was studied in relation to ITA, LB and ZT. The RLN was predominantly a posterior relation of the ITA in 86.25%, was deep to LB in 46.25% and was related posterior to ZT in 80% of cadaver dissected. The EBSLN has a variable relation with STA which was observed to lie at a distance of < 1 cm from STA in 66.25%. The difference between left and right side was not found to be statistically significant in all parameters (p > 0.05). The awareness and appreciation of the intricate topographical relations and its variations reinforce the surgeons to be careful when performing surgical procedures in the central compartment of the neck which avoid complications.

Relationship of Recurrent Laryngeal Nerve with Inferior Horn of Thyroid Cartilage, Berry's Ligament and Zuckerkandl's Tubercle

During neck surgery; Zuckerkandl's tubercle, Berry's ligament, the inferior horn of thyroid cartilages have become crucial anatomical landmarks in order to protect the integrity of the recurrent laryngeal nerve. Forty-two male postmortem human cadavers were used. The proximal part of the recurrent laryngeal nerve, before the inferior thyroid artery arises from its source has been observed in 87% inside the tracheoesophageal groove and in 13% running laterally to the trachea. The recurrent laryngeal nerve was encountered passing behind and through the branches of the inferior thyroid artery in 92% and 8% respectively. At all sides; the nerve was piercing the larynx 0.6 ± 0.1 mm below the inferior horn of thyroid cartilage, passing next to the inner-lower side of Berry's ligament and running under the lower middle part of Zuckerkandl's tubercle. These landmarks and their upper mentioned distances to the laryngeal nerve can be taken into consideration as important surgical guides.

Surgical Significance of Berry’s Posterolateral Ligament and Frequency of Recurrent Laryngeal Nerve Injury into the Last 2 cm of Its Caudal Extralaryngeal Part(P1) during Thyroidectomy

Background and Objectives: Recurrent laryngeal nerve injury is one of the major complications of thyroidectomy, with the lateral thyroid ligament (Berry’s ligament) being the most frequent site of nerve injury. Neuromonitoring during thyroidectomy revealed three possible anatomical regions of the recurrent laryngeal nerve P1, P2, and P3. P1 represents the recurrent laryngeal nerve’s caudal extralaryngeal part and is primarily associated with Berry’s ligament. The aim of this systematic review is to identify the anatomical region with the highest risk of injury of the recurrent laryngeal nerve (detected via neuromonitoring) during thyroidectomy and to demonstrate the significance of Berry’s ligament as an anatomical structure for the perioperative recognition and protection of the nerve. Materials and Methods: This study conducts a systematic review of the literature and adheres to all PRISMA system criteria as well as recommendations for systematic anatomical reviews. Three search engines (PubMed, Scopus, Cochrane) were used, and 18 out of 464 studies from 2003–2018 were finally included in this meta-analysis. All statistical data analyses were performed via SPSS 25 and Microsoft Office XL software. Results: 9191 nerves at risk were identified. In 75% of cases, the recurrent laryngeal nerve is located superficially to the ligament. In 71% of reported cases, the injury occurred in the P1 area, while the P3 zone (below the location where the nerve crosses the inferior thyroid artery) had the lowest risk of injury. Data from P1, P2, and P3 do not present significant heterogeneity. Conclusions: Berry’s ligament constitutes a reliable anatomical structure for recognizing and preserving recurrent laryngeal nerves. P1 is the anatomical area with the greatest risk of recurrent laryngeal nerve damage during thyroidectomy, compared to P2 and P3.

Improving Voice Outcomes after Thyroid Surgery and Ultrasound-Guided Ablation Procedures

The field of endocrine surgery has expanded from the traditional open neck approach to include remote access techniques as well as minimally invasive approaches for benign and malignant thyroid nodules. In experienced hands and with careful patient selection, each approach is considered safe, however complications can and do exist. Post-operative dysphonia can have serious consequences to the patient by affecting quality of life and ability to function at work and in daily life. Given the significance of post-procedural dysphonia, we review the surgical and non-surgical techniques for minimizing and treating recurrent laryngeal nerve injury that can be utilized with the traditional open neck approach, remote access thyroidectomy, or minimally invasive thermal ablation.

Clinical and Anatomical Factors Affecting Recurrent Laryngeal Nerve Paralysis During Thyroidectomy via Intraoperative Nerve Monitorization

Background

Despite all the technical developments in thyroidectomy and the use of intraoperative nerve monitorization (IONM), recurrent laryngeal nerve (RLN) paralysis may still occur. We aimed to evaluate the effects of anatomical variations, clinical features, and intervention type on RLN paralysis.

Method

The RLNs identified till the laryngeal entry point, between January 2016 and September 2021 were included in the study. The effects of RLN anatomical features considering the International RLN Anatomical Classification System, intervention and monitoring types on RLN paralysis were evaluated.

Results

A total of 1,412 neck sides of 871 patients (672 F, 199 M) with a mean age of 49.17 + 13.42 years (range, 18–99) were evaluated. Eighty-three nerves (5.9%) including 78 nerves with transient (5.5%) and 5 (0.4%) with permanent vocal cord paralysis (VCP) were detected. The factors that may increase the risk of VCP were evaluated with binary logistic regression analysis. While the secondary thyroidectomy (OR: 2.809, 95%CI: 1.302–6.061, p = 0.008) and Berry entrapment of RLN (OR: 2.347, 95%CI: 1.425–3.876, p = 0.001) were detected as the independent risk factors for total VCP, the use of intermittent-IONM (OR: 2.217, 95% CI: 1.299–3.788, 0.004), secondary thyroidectomy (OR: 3.257, 95%CI: 1.340–7.937, p = 0.009), and nerve branching (OR: 1.739, 95%CI: 1.049–2.882, p = 0.032) were detected as independent risk factors for transient VCP.

Conclusion

Preference of continuous-IONM particularly in secondary thyroidectomies would reduce the risk of VCP. Anatomical variations of the RLN cannot be predicted preoperatively. Revealing anatomical features with careful dissection may contribute to risk reduction by minimizing actions causing traction trauma or compression on the nerve.

The Most Common Anatomical Variation of Recurrent Laryngeal Nerve: Extralaryngeal Branching

Objective:

Extralaryngeal branching of recurrent laryngeal nerve (RLN) is frequent. In various studies, detection rate of extralaryngeal nerve branching was increased by intraoperative neuromonitorization (IONM). Our aim was evaluation of the relationship between the features of extralaryngeal branching of RLN and other anatomic variations in thyroidectomy patients under the guidance of IONM.

Methods:

Patients underwent thyroidectomy using IONM between January 2016 and December 2019 and whose RLNs were fully explored till the nerve’s entry point to the larynx, were enrolled to the study. Extralaryngeal branching of RLN was accepted as branching of the nerve at a ≥5 mm distance from its laryngeal entry point and having its all branches entering the larynx. Entrapment of RLN at the region of ligament of Berry (BL) by a vascular structure or posterior BL and relationship between RLN and inferior thyroid artery (ITA) was evaluated.

Results:

Out of 696 patients meeting the inclusion criteria, 1127 neck sides (536F and 160M) were evaluated. Mean age was 49.1±13.4 (range; 18–89). Nerve branching ratio was 35.3% and was higher in females than males (38.2%vs.25.8%, p<0.0001, respectively). Extralaryngeal branching of RLN was detected in 398 (35.3%) out of 1127 nerves. A total of 368 (92.5%) RLNs had two, 27 (6.8%) nerves had three, and 3 (0.7%) had multiple branches. RLN crossed anterior to and between branches of ITA more frequently in branching nerves than non-branching nerves (47.7 vs. 44.4% and 12.8% vs. 7.6%, respectively) but crossed posterior to ITA less frequently in branching nerves (38.5% vs. 48%, respectively, p=0.001). Entrapment of RLN at the region of BL was higher in branched nerves (25.9% vs. 17.5%, respectively, p=0.001). Entrapment of RLN wasmore frequent at the right side than left side both in branching (31.5% vs.19.4%, respectively, p=0.008) and non-branching nerves (20.6% vs. 14.4%, respectively).

Conclusion:

Extralaryngeal branching of RLN is not rare and mostly divided into two branches. Branching ratio is higher in females than males. In branching nerves, rate of crossing anterior to and between branches of ITA was higher, in non-branching nerves, rate of crossing posterior to ITA was higher. In branching nerves, possibility of entrapment of RLN at the region of BL was higher. Both in branching and non-branching nerves, entrapment of RLN at the region of BL was higher at the right side. Extralaryngeal branching, relationship between RLN and ITA, and entrapment of RLN at the region of BL are frequently seen and variable anatomic variations and cannot be foreseen preoperatively. Most of the extralaryngeal branches and their relationship with other variations can be detected by finding RLN at the level of ITA and following RLN until its entry point to the larynx.

Medial Approach for the Resection of Goiters with Suprahyoid, Retropharyngeal, or Substernal Extension

BACKGROUND

Resection of massive goiters with suprahyoid, retropharyngeal, and substernal extension may not be amenable to standard approaches. This study evaluates a surgical approach allowing resection of massive goiters with minimal substernal and deep neck dissection.

METHODS

Cases of thyroidectomy for goiters with substernal, retropharyngeal, or suprahyoid extension at a single institution from 2006 to 2017 were reviewed. The technique involves initial complete division of the medial thyroid tracheal attachments after identification of the RLN medial-inferiorly or superiorly. Deep components are then delivered into the superficial paratracheal region of the neck.

RESULTS

Sixty patients were included, 46 of which had substernal and 14 had only suprahyoid or retropharyngeal extension. Mean substernal extension was 3.7 cm (range 1.5-7.5 cm). The medial approach was successful in identifying the RLN in 70 (83%) of 84 goiter sides (71% medial-inferiorly and 29% superiorly). Standard inferior/lateral approaches were used in 12 (14%) nerves or not found until after goiter removal in 2 (2.5%). No patients required sternotomy or tracheotomy. Complications included postoperative seroma/hematoma (n = 9, 15%) with one re-exploration, transient RLN injury (n = 4, 4% of all lobectomies), transient hypocalcemia (n = 6, 16% of total thyroidectomies), permanent hypocalcemia (n = 2, 5% of total thyroidectomies), and permanent RLN paralysis (n = 1, 1% of all lobectomies).

CONCLUSION

Large suprahyoid, retropharyngeal, and substernal goiters were resected transcervically with low morbidity. Early complete division of Berry's ligament after medial-inferior RLN identification was achieved in a high proportion of patients, facilitating goiter delivery with minimal mediastinal and deep neck dissection.

Vocal cord paresis following single-session high intensity focused ablation (HIFU) treatment of benign thyroid nodules: incidence and risk factors

BACKGROUND

Vocal cord paresis (VCP) may occur following high intensity focused ultrasound (HIFU) of thyroid nodules. We hypothesised its occurrence relates to the distance of the focus point (FP) of the HIFU beams from the recurrent laryngeal nerve (RLN) and the thermal power that this point received. Their relationships were examined.

METHODS

One hundred and three patients who underwent HIFU for symptomatic benign thyroid nodule from October 2015 to March 2017 were analysed. All treatment images were captured and were later watched by 2 reviewers to identify three FPs closest to the tracheoesophageal groove (TEG) on transverse sonographic view. TEG was taken as the RLN position. After identifying these FPs, their distance (mm) from the TEG, thermal power (W) used and depth from skin (mm) were recorded. These parameters were compared between those with and without VCP. VCP was defined as a cord with reduced or no movement.

RESULTS

Four (3.9%) patients suffered from a unilateral VCP afterwards but they all recovered fully within 6 weeks. There were no significant differences in baseline characteristics and treatment efficacy between the two groups. The distance from TEG (OR = 1.706, 95%CI = 1.001 to 2.915, p = 0.050) was the only significant factor for VCP. None of the other variables including thermal power were significant.

CONCLUSIONS

The incidence of VCP was 3.9% (4/103) and they completely recovered within 6 weeks. The distance between the FP and the TEG was the only related factor for VCP. The safe distance between FP and TEG should be ≥1.1 cm.