Anatomical variations of the recurrent laryngeal nerve in Chinese patients: a prospective study of 2,404 patients

Parathyroidectomy for solitary parathyroid adenoma via trans-areola single site endoscopic approach: Results of a case-match study

BACKGROUND

This study aimed to establish the standardized procedure of trans-areola single site endoscopic parathyroidectomy (TASSEP), and to compare the performance of TASSEP with that of conventional open parathyroidectomy (COP).

METHODS

This study enrolled 40 patients with primary hyperparathyroidism (PHPT) who underwent TASSEP, and included 40 of 176 PHPT patients who underwent COP based on propensity score matching. The retrospective analysis was conducted based on prospectively collected data. Perioperative outcomes, including surgical profile, surgical burden and cosmetic results and follow-up were reported. The learning curve was described using a cumulative sum (CUSUM) analysis.

RESULTS

40 TASSEPs were completed successfully without conversions or severe complications. There was no statistically significant difference in operation time between TASSEP and COP groups (80.83 ± 11.95 vs. 76.95 ± 7.30 min, p = 0.084). Experience of 17 cases was necessitated to reach the learning curve of TASSEP. Postoperative pain score and traumatic index (C-reactive protein and erythrocyte sedimentation rate) in TASSEP were apparently lower than those in COP group (p < 0.05). During the proliferation and stabilization phases, TASSEP was associated with significantly better incision recovery and cosmetic scores. Postoperative serum calcium and PTH levels throughout the follow-up period indicated satisfactory surgical qualities in both groups.

CONCLUSION

Based on precise preoperative localization and intraoperative planning facilitated by three-dimensional (3D) virtual modeling, TASSEP can be feasibly performed on selected patients with satisfactory success rates and low complication rates, providing preferable cosmetic results and alleviating the surgical burden to a certain extent.

Comparison of diffusion ranges at different local anesthetic volumes during superior laryngeal nerve block

OBJECTIVES

Ultrasound-guided superior laryngeal nerve (SLN) block is a practical and painless approach to avoid the hemodynamic stress response during endotracheal intubation and relieve sore throat after laryngeal surgery. The main purpose of this study was to establish an optimal dosage of local anesthetic when performing SLN block to help anesthetists balance analgesia and side effects.

METHODS

Twenty fresh larynx specimens were obtained immediately after resection and then injected with 2-, 3-, 4-, or 5- mL of a lidocaine-blue dye mixture at bilateral SLN puncture sites. Superficial areas of deposited blue dye were measured. Dye leakage and surrounding dyed tissue were recorded. Another 40 patients were included in the ultrasound investigation. Distances between the internal branch of the SLN (iSLN) and adjacent structures were calculated.

RESULTS

The dye spread area was greater with the administration of larger doses, especially to the visceral space. A 2- or 3-mL injection of local anesthetic was sufficient to infiltrate the SLN gap. A higher incidence of dye leaking out of the thyrohyoid membrane and anterior epiglottis space was observed; furthermore, there was substantially more dyed hyoid/thyroid cartilage with 4 and 5 mL of injected dye mixture than 2 mL. There was no significant difference between the specimen and ultrasound measurements of for length of iSLN-adjacent structures.

CONCLUSIONS

In the Chinese population, 2- or 3- mL of local anesthetic is a safe dose during SLN block. A larger volume could overflow from the cavity to cause complications. The thyrohyoid membrane combined with the superior laryngeal artery is a reliable target for positioning the iSLN during ultrasound-guided regional anesthesia.

Anatomical variations of recurrent laryngeal nerve: a systematic review and meta-analyses

PURPOSE

The aim of this systematic review and meta-analysis was to systematically review and perform a meta-analysis on the anatomical variations of the RLN.

METHODS

We performed online research for studies that addressed anatomical variations of the RLN and laterality, published between 2015 and 2021. We found 230 articles, and nine were included.

RESULTS

Eight variations were found, with Type I prevailing (41.17%; 95% CI 19.44-64.88), extra laryngeal divergence of the RLN. The other types were: II-fan shape; III-distance greater than 5 mm to the cricothyroid joint; IV-thickening and adipopexy in the elderly; V-non-recurrent laryngeal nerve; VI-intracranial branch; VII-tortuous ascending RLN; and VIII-combination between the inferior branch of the NV and the ascending trunk of the RLN. Types I (p = 0) and III (p < 0.01) prevailed on the left and types II (p < 0.01) and V (p < 0.01) on the right.

CONCLUSIONS

It was observed that variations occurred due to the path of the RLN to the entrance to the larynx, its shape, and the age of the evaluated individual. The most frequent variation and side were, respectively, Type I, extra laryngeal divergence and left.

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.

Learning curve of trans-areola single-site endoscopic thyroidectomy in a high-volume center: A CUSUM-based assessment

BACKGROUND

Limited attempts have been made in trans-areola single-site endoscopic thyroidectomy (TASSET) due to technical challenges and the lengthy time for proficiency. This study aimed to define the learning curve of TASSET and to describe improvements in operative performance over time.

METHODS

Based on 222 consecutive TASSET procedures, the learning curve was established according to the operation time by using cumulative sum analysis (CUSUM). The end-point of learning curve was defined as the number of cases necessitated to reach the initial surgical proficiency stage. The demographic information, surgical and oncological outcomes, surgical stress, and postoperative complications were also analyzed.

RESULTS

There were 70 cases of simple lobectomy for benign nodules and 152 cases of lobectomy with central neck dissection (CND) for malignancy. The mean operative time was 106.54 ± 38.07 min (range: 46-274 min). The learning curve identified two phases: the skill acquisition phase (Case 1-Case 41) and the proficiency phase (Case 42-Case 222). There were no significant differences in demographic information, drainage amount and duration, oncological outcomes, and postoperative complications between the two phases (p > 0.05). Both operation time and postoperative hospitalization decreased significantly in Phase 2 (154.63 ± 52.21 vs. 95.64 ± 22.96 min, p < 0.001; 4.12 ± 0.93 vs. 3.65 ± 0.63 days, p < 0.001). Additionally, the mean variations of surgical stress factors (C-reactive protein and erythrocyte sedimentation rate) decreased significantly as the phase progress. The case number required for proficiency phase in benign and malignant tumor were 18 and 33, respectively, and lymph node resection posed a significant impact on the endpoint of the learning curve (p < 0.001). Meanwhile, the size of nodule showed no significant impact (p = 0.622). For right-handed surgeons, 16 cases and 25 cases were required for technical competence in left-sided and right-sided lesions, respectively, and no significant difference reached (p = 0.266).

CONCLUSIONS

TASSET has demonstrated safe and technically feasible with comparable oncological outcomes. Experience of 41 cases was required for surgical competence and proficiency. The initial learning stage could be more quickly adopted by high-volume thyroid surgeons with standardized procedures.

Systematic Review and Meta-Analysis: Recurrent Laryngeal Nerve Variants and Their Implication in Surgery and Neck Pathologies, Using the Anatomical Quality Assurance (AQUA) Checklist

INTRODUCTION

The recurrent laryngeal nerve (RLN) is the structure responsible for sensory and motor innervation of the larynx, and it has been shown that its lesion due to a lack of surgical rigor led to alterations such as respiratory obstruction due to vocal cords paralysis and permanent phonation impairment. The objectives of this review were to know the variants of the RLN and its clinical relevance in the neck region.

METHODS

This review considered specific scientific articles that were written in Spanish or English and published between 1960 and 2022. A systematic search was carried out in the electronic databases MEDLINE, WOS, CINAHL, SCOPUS, SCIELO, and Latin American and Caribbean Center for Information on Health Sciences to compile the available literature on the subject to be treated and was enrolled in PROSPERO. The included articles were studies that had a sample of RLN dissections or imaging, intervention group to look for RLN variants, or the comparison of the non-recurrent laryngeal nerve (NRLN) variants, and finally, its clinical correlations. Review articles and letters to the editor were excluded. All included articles were evaluated through quality assessment and risk of bias analysis using the methodological quality assurance tool for anatomical studies (AQUA). The extracted data in the meta-analysis were interpreted to calculate the prevalence of the RLN variants and their comparison and the relationship between the RLN and NRLN. The heterogeneity degree between included studies was assessed.

RESULTS

The included studies that showed variants of the RLN included in this review were 41, a total of 29,218. For the statistical analysis of the prevalence of the RLN variant, a forest plot was performed with 15 studies that met the condition of having a prevalence of less than 100%. As a result, the prevalence was shown to be 12% (95% CI, SD 0.11 to 0.14). Limitations that were present in this review were the publication bias of the included studies, the probability of not having carried out the most sensitive and specific search, and finally, the authors' personal inclinations in selecting the articles.

DISCUSSION

This meta-analysis can be considered based on an update of the prevalence of RLN variants, in addition to considering that the results show some clinical correlations such as intra-surgical complications and with some pathologies and aspects function of the vocal cords, which could be a guideline in management prior to surgery or of interest for the diagnostic.

Anatomy and motor function of extra-laryngeal branching patterns of the recurrent laryngeal nerve; an electrophysiological study of 1001 nerves at risk

INTRODUCTION

Safe thyroid surgery depends on a deep knowledge of human neck anatomy, including the recurrent laryngeal nerve (RLN). Anatomic variations such as extra-laryngeal terminal branching (ETB) are common.

PATIENTS AND METHODS

We studied the ETB pattern of 1001 RLNs at risk in 596 patients. We identified and exposed the location of division points on the cervical part of bifid RLN. The function of nerve branches was assessed through intraoperative nerve monitoring (IONM).

RESULTS

Bifid RLNs was identified in 39.6% of patients. The nerve-based prevalence of ETB was 28.5%. The prevalence of ETB for the right and left RLN was 21.8% and 35.5%, respectively (p < 0.001). The location of the division point was found in the middle, distal, and proximal segments in 48.8%, 33.3%, and 18% of bifid RLNs, respectively. Electrophysiological monitoring revealed motor functions in all anterior and in 7% of posterior branches. The rate of injury was 0.4%, and 1.1% in single trunk and bifid nerves, respectively (p = 0.360), and 3.9% in nerves with proximal branching (p = 0.084).

CONCLUSIONS

The ETB prevalence is high and showing division points in different cervical segments of the RLN. All anterior branches and some posterior branches contain motor fibers. Knowledge and awareness of these anatomic and functional variations are mandatory for every thyroid surgeon to avoid misidentification and misinterpretation of human RLN anatomy.

A clinically relevant formulation for direct administration of nerve specific fluorophores to mitigate iatrogenic nerve injury

Iatrogenic nerve injury significantly affects surgical outcomes. Although intraoperative neuromonitoring is utilized, nerve identification remains challenging and the success of nerve sparing is strongly correlated with surgeon experience levels. Fluorescence guided surgery (FGS) offers a potential solution for improved nerve sparing by providing direct visualization of nerve tissue intraoperatively. However, novel probes for FGS face a long regulatory pathway to achieve clinical translation. Herein, we report on the development of a clinically-viable, gel-based formulation that enables direct administration of nerve-specific probes for nerve sparing FGS applications, facilitating clinical translation via the exploratory investigational new drug (eIND) guidance. The developed formulation possesses unique gelling characteristics, allowing it to be easily spread as a liquid followed by rapid gelling for subsequent tissue hold. Optimization of the direct administration protocol with our gel-based formulation enabled a total staining time of 1-2 min for compatibility with surgical procedures and successful clinical translation.

Recurrent Nerve Injury After Total Thyroidectomy: Risk Factor Analysis of a Targeted NSQIP Data Set

BACKGROUND

Recurrent laryngeal nerve (RLN) injury is a significant complication after thyroidectomy. Understanding risk factors for RLN injury and the associated postoperative complications may help inform quality improvement initiatives.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) thyroidectomy-targeted database was utilized for patients undergoing total thyroidectomy between 2016 and 2017. Univariable and multivariable regression were used to identify factors associated with RLN injury.

RESULTS

A total of 6538 patients were identified. The overall rate of RLN injury was 7.1% (467/6538). Of these, 4129 (63.1%) patients had intraoperative neuromonitoring (IONM), with an associated RLN injury rate of 6.5% (versus 8.2% without). African American and Asian race, non-elective surgery, parathyroid auto-transplantation, and lack of RLN monitoring were all significantly associated with nerve injury on multivariable analysis (P<.05). Patients with RLN injury were more likely to experience cardiopulmonary complications, re-intubation, longer length of stay, readmission, and reoperation. Patients who had IONM and sustained RLN injury remained at risk for developing significant postoperative complications, although the extent of cardiopulmonary complications was less severe in this cohort.

DISCUSSION

Recurrent laryngeal nerve injury is common after thyroidectomy and is associated with significant morbidity, despite best practices. Attention to preoperative characteristics may help clinicians to further risk stratify patients prior to thyroidectomy. While IONM does not mitigate all complications, use of this technology may decrease severity of postoperative complications.

Care and Management of Voice Change for Thyroid Surgery: Korean Society of Laryngology, Phoniatrics and Logopedics Clinical Practice Guideline

Voice change is a common complaint after thyroid surgery and has significant impacts on quality of life. The Korean Society of Laryngology, Phoniatrics, and Logopedics set up a task force team to establish guideline recommendations on education, care, and management related to thyroid surgery. The guideline recommendations include preoperative voice education, management of anticipated voice change during surgery, and comprehensive voice care after thyroid surgery, including in-depth information and up-to-date knowledge based on validated literature. The committee constructed 14 key questions (KQ) in three categories: preoperative (KQ1-2), intraoperative (KQ 3-8), and postoperative (KQ 9-14) management and developed 18 evidence-based recommendations. The Delphi survey reached an agreement on each recommendation. Detailed evidence profiles are presented for each recommendation. The level of evidence for each recommendation is classified into high, moderate, and low-quality. The recommendation's strengths are adjusted to consider the level of evidence resulting in the recommendation and are divided into strong and weak. The guidelines are primarily targeted toward physicians who treat thyroid surgery patients and speech-language pathologists participating in patient care. These guidelines will also help primary care physicians, nurses, healthcare policymakers, and patients improve their understanding of voice changes and voice care after thyroid surgery.

Thyroidectomy for thyroid cancer via transareola single-site endoscopic approach: results of a case-match study with large-scale population

BACKGROUND

Due to technical challenges, single-site endoscopic thyroidectomy (SSET) is seldom reported and has been attempted in only limited cases. This large-scale study aimed to compare the clinical outcomes of standardized transareola SSET (TASSET) with those of conventional open thyroidectomy (COT) for thyroid cancer.

METHODS

The data were prospectively collected, and case-match study was performed at a ratio of 1:1 according to age, sex, body mass index, lesion size, number of lesion foci, lesion side, recurrent laryngeal nerve (RLN) exploration and pathology. Two hundred eligible patients underwent TASSET, and the same number of patients was selected for propensity score matching from 2256 patients who underwent COT. Perioperative data, including surgical profile, oncological and traumatic burdens, and cosmetic satisfaction, were analyzed.

RESULTS

No significant differences were observed in blood loss or drainage between TASSET and COT groups. There were no differences in operation time between TASSET and COT (106.39 ± 28.44 vs 102.55 ± 23.10 min, p = 0.154). A total of 3.63 ± 1.82 lymph nodes (LNs) were retrieved from CND with 0.96 ± 1.42 positive in TASSET. In COT, the total and positive LN yields were 3.77 ± 1.91 and 0.99 ± 1.40 (p = 0.445, p = 0.802). Cancer recurrence was not observed in either group. There were no differences in the occurrence of permanent and transient hoarseness or RLN injuries. Postoperative flap seroma or hematoma occurred in 12 TASSET patients and 58 COT patients (p < 0.001). The pain score, CRP level and ESR in TASSET group were lower than those in COT group. TASSET yielded significantly better incision recovery and cosmetic scores than did COT at both the proliferation and stabilization stages.

CONCLUSIONS

TASSET is technically feasible and yields enhanced recovery with minimally invasive and cosmetic advantages without compromising the level of safety or cancer eradication.

The intracranial branch; A rare anatomical variation of the recurrent laryngeal nerve; Case report

INTRODUCTION

The recurrent laryngeal nerve (RLN) originates from the Vagus nerve intrathoracically. It passes through the tracheoesophageal groove (TEG) in the neck and different variations in this section were observed. The RLN is at highest risk for injury during the thyroid surgery. Therefore, it is important to know variations to decrease the injury effectively.

PRESENTATION OF CASE

A 50 years-old woman with no thyroid related complaints except for enlargement of the thyroid gland in recent 12-months that annoyed her during neck movement and for aesthetic features. Medical, surgical, drugs, irradiation history, laboratory data, and physical examination was unremarkable except for multi-lobulated enlarged thyroid gland. The CT scanning study revealed intrathoracic extension of the gland. Patient underwent total thyroidectomy with suspicious diagnosis of multinodular goiter which was confirmed later by pathologic study. Intraoperative exploration of the right RLN discovered an intracranial branch originating from the recurrent laryngeal trunk just beneath the inferior thyroid artery (ITA) at the level of the nerve intersection. The branch then passed laterally about 1 cm and penetrated in ipsilateral carotid sheath.

DISCUSSION

The RLN has different anatomical variations in either the right or the left side of the neck. However extra-laryngeal nerve branching is the most common variation but other seldom variations including the non-RLN, and intracranial branch should be mentioned by surgeon intraoperatively.

CONCLUSION

To decrease iatrogenic injuries to RLN and its associated nerve branches knowledge of the nerve anatomy is mandatory for surgeon to prevent morbid side effects.

Anatomical Variations of the Recurrent Laryngeal Nerve and Implications for Injury Prevention during Surgical Procedures of the Neck

Accurate knowledge of anatomical variations of the recurrent laryngeal nerve (RLN) provides information to prevent inadvertent intraoperative injury and ultimately guide best clinical and surgical practices. The present study aims to assess the potential anatomical variability of RLN pertaining to its course, branching pattern, and relationship to the inferior thyroid artery, which makes it vulnerable during surgical procedures of the neck. Fifty-five formalin-fixed cadavers were carefully dissected and examined, with the course of the RLN carefully evaluated and documented bilaterally. Our findings indicate that extra-laryngeal branches coming off the RLN on both the right and left side innervate the esophagus, trachea, and mainly intrinsic laryngeal muscles. On the right side, 89.1% of the cadavers demonstrated 2–5 extra-laryngeal branches. On the left, 74.6% of the cadavers demonstrated 2–3 extra-laryngeal branches. In relation to the inferior thyroid artery (ITA), 67.9% of right RLNs were located anteriorly, while 32.1% were located posteriorly. On the other hand, 32.1% of left RLNs were anterior to the ITA, while 67.9% were related posteriorly. On both sides, 3–5% of RLN crossed in between the branches of the ITA. Anatomical consideration of the variations in the course, branching pattern, and relationship of the RLNs is essential to minimize complications associated with surgical procedures of the neck, especially thyroidectomy and anterior cervical discectomy and fusion (ACDF) surgery. The information gained in this study emphasizes the need to preferentially utilize left-sided approaches for ACDF surgery whenever possible.

Anatomical Variations in Recurrent Laryngeal Nerves in Thyroid Surgery

OBJECTIVE

To study terminal bifurcation of recurrent laryngeal nerves (RLNs) with original direction to larynx entry and to decrease the risk of vocal cord paralysis in thyroid patients.

METHODS

The RLNs of 294 patients (482 sides) were dissected according to the branches into the larynx, and the original direction of each RLN trunk in thyroid surgery was recorded.

RESULTS

(1) About 30.9% of the RLNs gave off multiple branches into the larynx. (2) Two and 3 branches of RLNs into the larynx were found in 25.5% and 5.4% of the cases, respectively. (3) In 0.4% or 2 cases, the RLN trunk combined with the inferior branch of the vagus nerve. (4) Nonrecurrent laryngeal nerve appeared in 2 cases. (5) On the left side, 68.0%, 25.6%, and 6.4% of cases were found with 1, 2, and 3 bifurcations of RLN to larynx entry, respectively. On the right side, 69.8%, 25.8%, and 4.4% cases were identified with 1, 2, and 3 bifurcations of RLN to larynx entry, respectively. (6) The combining dissection approach was proved as successful and safe for protecting the RLN with no permanent RLN paresis.

CONCLUSIONS

Because of the anatomical variation in RLNs with extralaryngeal bifurcation, it is necessary to increase the awareness of surgeons about these variations so as to protect bifurcated nerves in thyroid surgery.

The Internal Superior Laryngeal Nerve in Humans: Evidence for Pure Sensory Function

OBJECTIVES

To determine if the internal branch of the superior laryngeal nerve (iSLN) provides direct motor innervation to the interarytenoid muscle, a laryngeal adductor critical for airway protection. We studied the iSLN-evoked motor response in the interarytenoid and other laryngeal muscles. If the iSLN is purely sensory, there will be no detectable short latency motor response upon supramaximal stimulation, indicating the absence of a direct efferent conduction path.

STUDY DESIGN

Intraoperative case series.

METHODS

In seven anesthetized patients undergoing laryngectomy for unilateral laryngeal carcinoma, the iSLN of the unaffected side was electrically stimulated intraoperatively with 0.1-ms pulses of progressive intensities until supramaximal stimulation was reached. Electromyographic responses were measured in the ipsilateral interarytenoid, thyroarytenoid, and cricothyroid muscles.

RESULTS

None of the subjects exhibited short-latency interarytenoid motor responses to iSLN stimulation. Supramaximal electrical stimulation of the intact iSLN evoked ipsilateral motor responses with long latencies: 18.7-38.5 ms in the interarytenoid (n = 6) and 17.8-24.9 ms in the thyroarytenoid (n = 5). Supramaximal stimulation of the recurrent laryngeal nerve evoked ipsilateral motor responses with short latencies: 1.6-3.9 ms in the interarytenoid (n = 6) and 1.6-2.7 ms in the thyroarytenoid (n = 6).

CONCLUSION

The iSLN provides no functional efferent motor innervation to the interarytenoid muscles. The iSLN exclusively evokes an interarytenoid motor response via afferent activation of central neural circuits that mediate the laryngeal reflex arc. These findings suggest that the role of the iSLN in vital laryngopharyngeal functions, such as normal swallowing and protection of the airway from aspiration, is purely sensory.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E207-E211, 2021.

Anatomical variation in the right non-recurrent laryngeal nerve reported from studies using pre-operative arterial imaging

The right non-recurrent (inferior) laryngeal nerve (NRLN) is a rare anatomical variant associated with an arterial anomaly, the aberrant right subclavian artery (ARSA), that is detectable by pre-operative imaging (POI) using computed tomography and/or ultrasound. Most surgical studies have utilized two major types, NRLNs arising near the upper pole of the thyroid gland (type 1), vs. at a lower level (type 2) but with two subtypes defined by relationships to the inferior thyroid artery (ITA). This review found 8 English language surgical studies using POI that reported at least 1 NRLN and had anatomical information; of the 88 right NRLNs, 69.3% were classified as type 2 and 30.7% as type 1. Meta-analysis yielded a weighted proportion of 74.0% for type 2, but with substantial heterogeneity. For a subgroup of 5 POI studies with information on subtypes, 22 (59.5%) of 37 type 2 nerves were type 2a (i.e., running at or above the ITA). Similarly, a separate review of large surgical series without POI found that 60.4% of all 91 type 2 NRLNs were type 2a. The study findings should be relevant to the increasing numbers of anterior neck surgeries including bilateral thyroidectomies. A need was identified for studies on inter-observer reliability (agreement) among surgeons on NRLN types, and on injury rates (and related symptoms) by the type of NRLN.

Intraoperative carbon nanoparticles mapping in secondary total thyroidectomy for recurrent thyroid nodules: Results of a 8-criterion case-match study (case control study)

BACKGROUND

The extent of total thyroidectomy in the management of multinodular goiter remains unclear. Compared to primary thyroidectomy, secondary total thyroidectomy is more difficult to perform and carries a significantly higher risk of postoperative complications such as recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism. In this study, we aimed to evaluate the efficacy and safety of intraoperative carbon nanoparticle (CN) mapping in patients undergoing secondary total thyroidectomy.

METHODS

We performed a case-matched analysis of a prospectively maintained database using 8 specific criteria to compare perioperative outcomes after primary total thyroidectomy to those after secondary total thyroidectomy with intraoperative CN mapping. The criteria included age, sex, operative procedure, RLN/parathyroid glands (PGs) exploration, preoperative vocal cord calcium abnormalities, and pathological results. Thirty-five patients underwent secondary total thyroidectomy with intraoperative CN mapping due to recurrent thyroid nodules or development of nodules suspicious for malignancy after subtotal thyroidectomy. Fifty exact matches for all 8 criteria were identified from the database in our previous study, which included records of 3078 primary thyroidectomies without CNs. Perioperative outcomes, surgical technique, and complications were analyzed.

RESULTS

The RLNs were successfully identified in all 35 patients. Among three patients that experienced slight hoarseness, one had an RLN end-to-end anastomosis with subsequent improvement in the during the 12-month follow-up period. Two patients experienced changes in vocal tone, but recovered after several months. Two patients underwent parathyroid auto-transplantations, and subsequently presented with transient hypocalcaemia. Their symptoms gradually remitted within one year. Except for mean operation time, there were no statistically significant differences in complications between the primary total thyroidectomies and the secondary total thyroidectomy with CNs.

CONCLUSIONS

Intraoperative CN mapping, expert knowledge of the jugular anatomy, and standardized resection procedures can minimize the incidence of complications such as RLN palsy and hypoparathyroidism after secondary total thyroidectomy.

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

The extralaryngeal bifurcation point of the recurrent laryngeal nerve (RLN) is typically located in a mean distance of 0–2 cm 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 anatomical aberration leads to an injury-free thyroid surgery.