Revisited anatomy of the recurrent laryngeal nerves

Prognostic Factors for Recovery from Left Recurrent Laryngeal Nerve Palsy After Minimally Invasive McKeown Esophagectomy: A Retrospective Study

BACKGROUND

Recurrent laryngeal nerve (RLN) palsy is a serious complication of esophagectomy that affects the patient's phonation and the ability to prevent life-threatening aspiration events. The aim of this single-center, retrospective study was to investigate the clinical course of left RLN palsy and to identify the main prognostic factors for recovery.

METHODS

The study cohort consisted of 85 patients who had developed left RLN palsy after minimally invasive McKeown esophagectomy. Vocal cord function was assessed in all participants through laryngoscopic examinations, both in the immediate postoperative period and during follow-up. Permanent palsy was defined as no evidence of recovery after 6 months. Univariate and multivariable logistic regression analyses were applied to evaluate the associations between different variables and the outcome of palsy.

RESULTS

Twenty-two (25.8%) patients successfully recovered from left RLN palsy. On multivariable logistic regression analysis, active smoking (odds ratio [OR] 0.335, p = 0.038) and the use of thoracoscopic surgery (vs. robotic surgery; OR 0.264, p = 0.028) were identified as independent unfavorable predictors for recovery from palsy. The estimated rates of recovery derived from a logistic regression model for patients harboring two, one, or no risk factors were 13.16%, 31.15-34.75%, and 61.39%, respectively.

CONCLUSION

Only one-quarter of patients who had developed left RLN palsy after minimally invasive McKeown esophagectomy were able to fully recover. Smoking habits and the surgical approach were identified as key determinants of recovery. Patients harboring adverse prognostic factors are potential candidates for early intervention strategies.

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.

Reversible Ortner's Syndrome as a Presenting Feature of Thyrotoxicosis in an Adolescent: A Rare Case Report

Ortner's or cardiovocal syndrome is hoarseness attributable to left recurrent laryngeal nerve (RLN) palsy associated with mechanical compression of the nerve by pathologically enlarged cardiovascular structures. Ortner's syndrome is a rare condition, and to our knowledge, only a few cases have been reported in Korea. Furthermore, this condition is extremely uncommon in pediatric patients with thyrotoxicosis-related RLN paralysis. We report a case of reversible Ortner's syndrome in an adolescent who presented with secondary pulmonary hypertension related to thyrotoxicosis.

Modern Surgical Techniques of Thyroidectomy and Advances in the Prevention and Treatment of Perioperative Complications

Thyroid cancer is the most common cancer of the endocrine system, and, in recent years, there has been a phenomenon of overdiagnosis followed by subsequent overtreatment. This results in an increasing number of thyroidectomy complications being faced in clinical practice. In this paper, we present the current state of knowledge and the latest findings in the fields of modern surgical techniques, thermal ablation, the identification and assessment of parathyroid function, recurrent laryngeal nerve monitoring and treatment and perioperative bleeding. We reviewed 485 papers, from which we selected 125 papers that are the most relevant. The main merit of this article is its comprehensive view of the subject under discussion-both general, concerning the selection of the appropriate method of surgery, and particular, concerning the selection of the appropriate method of prevention or treatment of selected perioperative complications.

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.

Systematic Review of Comparison of use of Ultrasonic Scalpel Versus Conventional Haemostatic Techniques in Performing Thyroid Surgery

Haemostasis during any surgical procedure is fundamental for attaining a positive patient outcome. Safe thyroid surgery requires meticulous attention for careful control of bleeding and safe guarding important structures like recurrent laryngeal nerve. Many methods such as ligation and suturing, electro ligation sealing, coagulation, and ultrasonic coagulation have been put to use for achieving haemostasis. The objective of this systemic review was to compare and review the surgical outcomes between harmonic (ultrasonic) scalpel and conventional ligature techniques in performing thyroid surgery. The systematic review was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and checklist with a total of 11 studies selected for qualitative analysis. The statistical software Review Manager 5.4.1 provided by the Cochrane Collaboration was used for performing the analysis on the two groups. It was concluded that the use of harmonic scalpel for thyroid surgery is useful for reducing operative time, postoperative pain, drainage volume and transient hypocalcemia, hence can be a reliable and a safe tool compared to conventional techniques often used for surgery.

Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure

Damage to the recurrent laryngeal nerve (RLN) caused by supraphysiological compression or tension imposed by adjacent tissue structures, such as the aorta, may contribute to onset of idiopathic unilateral vocal fold paralysis (iUVP) resulting in difficulty speaking, breathing, and swallowing. We previously demonstrated in adolescent pigs that the right RLN epineurium exhibits uniform composition of adipose tissue, with larger quantities along its length within the neck region in contrast to the left RLN that shows greater collagen composition in the thoracic region and greater quantities of adipose tissue in the neck region. In contrast, the epineurium in piglets was primarily composed of collagen tissue that remained uniform along the length of the left and right RLNs. Tensile testing of the left and right RLN in piglets and pigs showed associated differences in strain by RLN side and segment by age. The goal of this study was to investigate how external hydrostatic compression of the RLN affects the nerve's connective tissue and microstructure. RLN segments were harvested from the distal (cervical/neck) regions and proximal (subclavian for the right RLN, thoracic for the left RLN) regions from eight adolescent pigs and nine piglets. RLN segments were isolated and assessed under fluid compression to test hypotheses regarding epineurium composition and response to applied forces. Second harmonic generation (SHG) imaging of epineurial collagen was conducted at 0, 40, and 80 mmHg of compression. The cartesian strain tensor, principal strain (Eps1), and principal direction of the RLN collagen fibers were determined at each pressure step. Significantly larger values of the 1st principal strain occurred in the proximal segments of the pig left RLN when compared to the same segment in piglets (p = 0.001, pig = 0.0287 [IQR = 0.0161 - 0.0428], piglet = 0.0061 [IQR = 0.0033 - 0.0156]). Additionally, the median transverse strain Eyy) for the second pressure increment was larger in the right proximal segment of pigs compared to piglets (p < 0.001, pig = 0.0122 [IQR = 0.0033 - 0.0171], piglet = 0.0013 [IQR = 0.00001 - 0.0028]). Eyy values were significantly larger in the right proximal RLN versus the left proximal RLNs in pigs but not in piglets (p < 0.001). In contrast to piglets, histological analysis of pig RLN demonstrated increased axial alignment of epineurial and endoneurial collagen in response to compressive pressure. These findings support the hypothesis that the biomechanical response of the RLN to compressive pressure changed from being similar to being different between the right and left RLNs during development in the porcine model. Further investigation of these findings associated with age-related onset of idiopathic UVP may illuminate underlying etiologic mechanisms. STATEMENT OF SIGNIFICANCE: Damage to the recurrent laryngeal nerve (RLN) caused by compression imposed by the aorta may contribute to the onset of left-sided idiopathic unilateral vocal fold paralysis resulting in difficulty speaking, breathing, and swallowing. The goal of this study was to investigate how compression affects the connective tissue and microstructure of the RLN. We quantified the pressure induced deformation of the RLN using multiphoton imaging as a function of both location (proximal versus distal) and age (piglets, adolescent pigs). Our results demonstrate that the biomechanical response of the RLN to compression changes in the right versus left RLN throughout development, providing further evidence that the the left RLN is exposed to increasing dynamic loads with age.

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.

An atypical bilateral trifurcation of recurrent laryngeal nerve

Background

Thyroidectomy is a frequently performed surgery for benign and malignant conditions. Nevertheless, one of the most critical complications of thyroidectomy is recurrent laryngeal nerve (RLN) injury leading to vocal cord paralysis. A thorough knowledge of the anatomical variations of RLN and ligation of the related vessels close to their distal branches is critical to avoid injury.

Case presentation

Here, we report the first case of bilateral trifurcation of recurrent laryngeal nerve (RLN) in a 40-year old woman with multinodular goitre. Total thyroidectomy was performed and RLN was preserved bilaterally. Followed by a precise dissection, fine branches were traced penetrating the larynx. We did not observe any further post-operative complications and patient was discharged with desired outcomes.

Conclusions

Anatomical variations of the RLN include—bifurcations, trifurcations, relation of RLN with inferior thyroid artery (ITA) and presence of non-recurrent laryngeal nerve. Only RLN dividing at a distance greater than 5 mm (branching point distance) before its entry into the larynx beneath the cricothyroid are said to bifurcate or trifurcate. Approximately 25% of nerves show branching [71%—unilateral and 18%—bilateral bifurcation]. Incidence of unilateral trifurcations have been noted be 0.9% and the rates of bilateral trifurcation and the divisions of the branches is yet to be ascertained. This is the first report of a bilateral trifurcation of RLN, detected in patient with multinodular goitre and hence warrants a precise analysis of variations of the RLN in patients undergoing thyroidectomy, which is critical to prevent RLN injury.

Surgically Acquired Vocal Cord Palsy in Infants and Children with Congenital Heart Disease (CHD): Description of Feeding Outcomes

Impaired swallowing in infants can impact upon the ability to feed orally, often resulting in dependency on supplementary feeding. Such difficulties can lead to an increased burden of care and associated costs. The primary aim of this study was to investigate the impact of vocal cord palsy (VCP), acquired intraoperatively during cardiac surgery, on the feeding outcomes of infants at a tertiary metropolitan children's hospital. An additional aim was to obtain preliminary information on the impact of feeding difficulties in this group on the quality of life of parents and families. A review of 48 patients who had been referred to the speech pathology service was undertaken. Participants presented with heterogeneous cardiac diagnoses, and had an initial Videofluoroscopic Swallow Study (VFSS) at a median corrected age of 3.6 weeks. Sixty percent of participants presented with silent aspiration on VFSS. Thirty percent of participants required supplementary tube feeding more than 6 months post-surgery. Six percent of participants with poor feeding progress and persistent aspiration required further surgical intervention to support nutrition. Findings revealed no significant relationship between participant factors and the presence of feeding difficulties, however, infants with concomitant genetic and syndromic conditions were found to be most at-risk for long-term feeding difficulties. Analysis of informal parent questionnaire responses indicated parents experienced stress and anxiety after their child's discharge. This was noted in regard to their child's feeding, which impacts quality of life across a number of domains. Findings of this study highlight the importance of communicating the potential feeding difficulties to parents of at-risk infants prior to cardiac surgery. This study further highlighted the importance of routine post-operative otorhinolaryngology examinations following high-risk surgeries, as well as speech pathology management for all infants and children identified with VCP. Post-operative input from appropriately trained Speech Pathologists is vital in assisting parents to support and mitigate their child's difficulties through the provision of early intervention for feeding difficulties.

Recurrent Laryngeal Nerve Injury Near the Nerve Entry Point in Total Endoscopic Thyroidectomy: A Retrospective Cohort Study

Background

Recurrent laryngeal nerve injury (RLNI) still occurs in total endoscopic thyroidectomy (TET) by using intraoperative neuromonitoring (IONM). As the region where most injuries occur, more attention should be paid to RLNI near the nerve entry point (NEP) in TET.

Materials and Methods

This cohort study collected retrospectively data from 415 patients who underwent TET between February 2012 and December 2019. The functions of the recurrent laryngeal nerve (RLN) in TET were recorded by IONM. The patients with RLNI near the NEP were followed up by laryngoscopies. The demographic and clinical characteristics, the mechanisms of RLNI, and the outcomes of RLNI were recorded and analyzed.

Results

There were a total of 444 at-risk nerves in 405 patients were analyzed. The incidence of RLNI near the NEP was 7.9%. RLNs with extralaryngeal branches were more likely to be injured near the NEP (P = 0.037). The incidences of different types of RLNI, in order of frequency, were 68.8% for thermal injury (n = 22), 28.1% for traction/compression injury (n = 9), and 3.1% for transverse injury (n = 1). A total of 93.8% (n = 30) of RLNI patients had complete recovery of vocal cord activity function.

Conclusion

The extralaryngeal branch was a risk factor for RLNI near the NEP in TET. Thermal injury caused by an ultrasonic scalpel was the most common cause of RLNI near the NEP. Most RLNIs near the NEP would eventually recover.

Post-thyroidectomy complications in southwestern Saudi Arabia: a retrospective study of a 6-year period

BACKGROUND

Thyroidectomy is the surgical removal of all or part of the thyroid gland for non-neoplastic and neoplastic thyroid diseases. Major postoperative complications of thyroidectomy, including recurrent laryngeal nerve injury, hypocalcemia, and hypothyroidism, are not infrequent.

OBJECTIVE

Summarize the frequency of surgical complications of thyroidectomy.

DESIGN

Retrospective.

SETTING

Secondary health facility in southwestern Saudi Arabia.

PATIENTS AND METHODS

We collected data from the records of patients who were managed for thyroid diseases between December 2013 and December 2019.

MAIN OUTCOME MEASURE

Complications following thyroidectomy.

SAMPLE SIZE

339 patients, 280 (82.6%) females and 59 (17.4%) males.

RESULTS

We found 311 (91.7%) benign and 28 (8.3%) malignant thyroid disorders. Definitive management included 129 (38.1%) total thyroidectomies, 70 (20.6%) hemithyroidectomies, 10 (2.9%) subtotal thyroidectomies and 5 (1.5%) near-total thyroidectomies with 125 (36.9%) patients treated non-surgically. The overall complication rate was 11.3%. There were 4 (1.9%) patients with recurrent laryngeal nerve palsy, 16 (7.5%) patients with temporary hypoparathyroidism, 1 (0.5%) patient with paralysis of the external branch of the superior laryngeal nerve and 3 (1.4%) patients with wound hematoma.

CONCLUSION

The rate of complications following thyroidectomy is still high. There is a need for emphasis on comprehensive measures to control the high rate of complications.

LIMITATIONS

Retrospective design and no long-term follow up to monitor late complications.

CONFLICT OF INTEREST

None.

Right-sided Zenker's diverticulum resected using intraoperative neuromonitoring

Right-sided Zenker's diverticulum is a rare pharyngoesophageal diverticulum. The risk of intraoperative injury of the recurrent laryngeal nerve is high during transcervical diverticulectomy because this nerve presents many variations of extralaryngeal bifurcation before entry into the larynx. We present a case of right-sided Zenker's diverticulum that was safely resected with the use of intraoperative neuromonitoring to prevent right recurrent laryngeal nerve injury. A 55-year-old man complaining of chronic cough and regurgitation of ingested food was diagnosed as having right-sided Zenker's diverticulum and underwent open transcervical diverticulectomy and cricopharyngeal myotomy. The location of the right recurrent laryngeal nerve was accurately determined during dissection by intermittent stimulation using a monopolar stimulation probe of an intraoperative neuromonitoring system to avoid injury. The postoperative course was uneventful, and postoperative evaluation showed no vocal cord paralysis. Intraoperative neuromonitoring may be beneficial during transcervical diverticulectomy for right-sided Zenker's diverticulum nearby the right recurrent laryngeal nerve, which can present with many variations of extralaryngeal bifurcation.

Mechanisms of recurrent laryngeal nerve injury near the nerve entry point during thyroid surgery: A retrospective cohort study

BACKGROUND

The use of intraoperative neuromonitoring (IONM) for visual identification of recurrent laryngeal nerve (RLN) has decreased the rates of RLN injury (RLNI) during thyroid surgery. However, little attention has been paid to RLNI near the nerve entry point (NEP), where most injuries occur. The aim of this study was to determine the mechanism of RLNI near the NEP and to describe the recovery of nerve function.

METHODS

Patients undergoing thyroid surgery were analyzed to identify true loss of signal (LOS) by IONM. Follow-up for vocal cord palsy (VCP) was confirmed by a postoperative laryngoscopy. The risk factors for RLNI, the type of RLNI, the prevalence of VCP and the time for VCP recovery were all recorded and analyzed.

RESULTS

We analyzed 3582 at-risk nerves in 2257 surgical patients. The overall rate of RLNI near the NEP in at-risk nerves was 3.2%. RLNI was more likely to occur in nerves with extralaryngeal bifurcation (p = 0.013). The distribution of RLNI types, in order of frequency, was traction (52.6%; n = 61), compression (38.8%; n = 45), thermal (7.8%; n = 9), and nerve transection (0.9%; n = 1). Complete recovery from VCP was documented in 93.1% (n = 108) of RLNI.

CONCLUSION

Patients with a bifurcated RLN were at a higher risk of RLNI near the NEP than those without bifurcation. Traction and compression injuries occurred most frequently, but would eventually recover. Excessive stretching of the thyroid lobe played a role in RLNIs near the NEP.

Prospective anatomical study to determine the site of insertion of recurrent laryngeal nerve into the larynx

OBJECTIVES

Determine whether the insertion site of the recurrent laryngeal nerve (RLN) occurs at a predictable distance from the midline trachea, to help guide safe dissection during thyroid surgery.

DESIGN

Prospective clinical trial. At the inferior edge of the cricoid cartilage, we measured the distance from mildline trachea to the RLN insertion site.

SETTING

Single institution.

PARTICIPANTS

50 consecutive patients undergoing thyroid surgery.

MAIN OUTCOME MEASURES

Distance from midline trachea to laryngeal insertion of RLN.

RESULTS

The study population included 36 women and 14 men, with 72 total nerves measured. The average distance-to-midline + standard deviation (range) of the RLN was 20.7 + 2.3 (17-26) mm in women compared to 26.3 + 2.1 (22-32) mm in men.

CONCLUSION

The insertion point of the RLN into the larynx at the level of inferior border of the cricoid cartilage can be reliably predicted, to facilitate early identification of the RLN during thyroid surgery.

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.

TOTAL THYROIDECTOMY FOR MALIGNANCY - IS CENTRAL NECK DISSECTION A RISK FACTOR FOR RECURRENT NERVE INJURY AND POSTOPERATIVE HYPOCALCEMIA? A TERTIARY CENTER EXPERIENCE IN ROMANIA

Introduction

Surgery for thyroid cancer carries a higher risk of morbidity given the region's complicated anatomy, the setting of malignancy and extent of the surgery.

Aim

To investigate the rate of complications related to the recurrent nerve and parathyroid glands lesions in patients with thyroid carcinoma that undergo thyroid surgery and lymph node dissection.

Patients and Methods

The data of 71 patients who underwent total thyroidectomy and 19 patients who underwent total thyroidectomy and central neck dissection with various associated neck dissection techniques were investigated using appropriate statistical tests.

Results

As expected, the rate of recurrent nerve injury observed in the neck dissection group was higher than in the total thyroidectomy group (15.7% vs. 2.8%, p=0.05). As for postoperative hypocalcemia, the rate observed in the neck dissection group, both for postoperative day 1 (p<0.0001) and day 30 (p=0.0003) was higher than in the total thyroidectomy group (68.4% vs. 19.7% postoperative day 1, 31.5% vs. 4.2% postoperative day 30).

Conclusions

The risk of morbidity concerning the recurrent nerve injury and postoperative hypoparathyroidism increases with the extent of surgery. Extensive surgery may achieve proper oncologic outcomes but increases the risk of postoperative morbidity and decreases quality of life. In deciding for extensive surgery, both patient and medical team need to understand these risks.

A systematic approach to the recurrent laryngeal nerve dissection at the cricothyroid junction

Background

To describe and evaluate a four step systematic approach to dissecting the recurrent laryngeal nerve (RLN) starting at the cricothyroid junction during thyroid surgery (subsequently referred to as the retrograde medial approach).

Methods

All thyroidectomies completed by the senior author between August 2014 and January 2016 were retrospectively reviewed. Patients were excluded if concurrent lateral or central neck dissection was performed. A follow up period of 1 year was included.

Results

Surgical photographs and illustrations demonstrate the four steps in the retrograde medial approach to dissection of the RLN in thyroid surgery.

Three hundred forty-two consecutive thyroid surgeries were performed in 17 months, including 213 hemithyroidectomies, 91 total thyroidectomies, and 38 completion thyroidectomies. The rate of temporary and permanent hypocalcemia was 13% (95% confidence interval [CI]: 8–20%) and 3% (95% CI: 1–8%) respectively. The rate of temporary and permanent vocal cord palsy was 9% (95% CI: 6–12%) and 0.3% (95%CI: 0.01–2%) respectively. The median surgical times for hemithyroidectomy, total thyroidectomy, and completion thyroidectomy were 39 min (Interquartile range [IQR]: 33–47 min), 48 min (IQR: 40–60 min), and 40 min (IQR: 35–51 min) respectively. 1% of cases required conversion to an alternative surgical approach.

Conclusion

In a tertiary endocrine head and neck practice, the routine use of the retrograde medial approach to RLN dissection is safe and results in a short operative time, and a low conversion rate to other RLN dissection approaches.

Bilateral patterns and motor function of the extralaryngeal branching of the recurrent laryngeal nerve

PURPOSE

To evaluate the bilateral patterns and motor function of the extralaryngeal branches (ELB) of the recurrent laryngeal nerve(RLN).

METHODS

This study included 500 consecutive patients who underwent total thyroidectomy. Intraoperative nerve monitoring (IONM) was used in 230 patients. Demographic data, indications for surgery, the bilateral patterns of ELB of the RLN, electromyographic activity of the ELB, distance between the branching point to the entrance into the larynx, and the rate of postoperative morbidity were analyzed.

RESULTS

The overall rate of ELB was 27.6% (276/1000). A single trunk of the RLN on both sides was found in 269 (54%) patients, whereas ELB on both sides was observed in 45 (9%) patients. The rates of ELB on the left and right sides were 26.6 and 28.6%, respectively. Of the 89 branched nerves which were dissected using IONM, an evoked motor response was present in 100% of the anterior branches and 5.6% of the posterior branches. The mean branching distance of the RLN was significantly greater in female patients than in male patients on the left side (p = 0.031). The patterns of ELB showed no significant difference in male and female patients. The rates of postoperative transient and permanent hypoparathyroidism and unilateral RLN palsy were 21.6 and 2.8%, and 3.2 and 0.8%, respectively. The rate of RLN palsy was higher in branched nerves compared to those with a single trunk (0.75 vs 0.3%; p = 0.2).

CONCLUSION

Unilateral ELB of the RLN might be observed in approximately 1/4 of the patients, while bilateral branching is rare. A few number of posterior branches of the RLN can have motor function. The RLN's with ELB might have a higher risk of injury compared to those with a single trunk.

Intrathyroidal carotid artery and nonrecurring right recurrent laryngeal nerve: A case report

BACKGROUND

When performing thyroidectomy, knowledge of normal anatomy and variants is vital to avoid injuring nearby structures. Typically, the bilateral carotids course posterolateral to the thyroid gland. We describe a rare variant of an intrathyroidal carotid artery, not previously described in the literature.

METHODS

A 23-year-old woman with a strong family history of thyroid cancer presented with a left thyroid nodule, and a fine-needle aspiration biopsy revealing papillary thyroid carcinoma. She underwent total thyroidectomy.

RESULTS

Intraoperatively, the carotid was found coursing centrally through the right lobe parenchyma, associated with an ipsilateral nonrecurrent recurrent laryngeal nerve (NRLN) entering the cricothyroid joint superolaterally.

CONCLUSION

This is, to our knowledge, the first report of such an anatomic variant in the medical literature. Aberrant carotid artery anatomy may potentially cause life-threatening surgical complications and should be considered preoperatively. Furthermore, recognition of concurrent recurrent laryngeal nerve (RLN) anomalies with vascular variations allows identification of nonrecurrent nerves.

Extralaryngeal division of the recurrent laryngeal nerve: A common and asymmetric anatomical variant

OBJECTIVE

Recognition of extralaryngeal branching of the recurrent laryngeal nerve is crucial because prevention of vocal cord paralysis requires preservation of all branches of the recurrent laryngeal nerve. We assessed the prevalence of extralaryngeal branching of the recurrent laryngeal nerve and the median branching distance from the point of bifurcation to the entry point of the nerve into the larynx.

MATERIAL AND METHODS

Prospective operative data on recurrent laryngeal nerve branching were collected from 94 patients who underwent thyroid or parathyroid surgery between September 2011 and May 2012.

RESULTS

A total of 161 recurrent laryngeal nerves were examined (82 right, 79 left). Overall, 77 (47.8%) of 161 recurrent laryngeal nerves were bifurcated before entering the larynx. There were 36 (43.9%) branching nerves on the right and 41 (51.9%) branching nerves on the left, and there was no significant difference between the sides in terms of branching (p=0.471). Among 67 patients who underwent bilateral exploration, 28.4% were found to have bilateral branching, 40.3% had unilateral branching, and the remaining 31.3% had no branching. The median branching distance was 15 mm (5-60mm).

CONCLUSION

Extralaryngeal division of recurrent laryngeal nerve is a common and asymmetric anatomical variant. These variations can be easily recognized if the recurrent laryngeal nerve is identified at the level of the inferior thyroid artery and then dissected totally to the entry point of the larynx. Inadvertent division of a branch may lead to vocal cord palsy postoperatively, even when the surgeon believes the integrity of the nerve has been preserved.

Some posterior branches of extralaryngeal recurrent laryngeal nerves have motor fibers

OBJECTIVES/HYPOTHESIS

Anatomical variations of the recurrent laryngeal nerve (RLN), such as extralaryngeal branching, are a well-known risk factor for RLN injury during thyroid surgery. This study aimed to analyze the surgical anatomy and to investigate the existence of posterior branch motor fibers of extralaryngeal RLNs.

STUDY DESIGN

Prospective consecutive observational study.

METHODS

This was a prospective cohort study of 366 patients between January 2014 and February 2016. Operative data included the type of operation, incidence of nerve bifurcation, the distances among anatomical landmarks. The motor fibers were evaluated using neurostimulation with laryngeal palpation.

RESULTS

A total of 667 RLNs at risk were analyzed in this study, and of these 103 (14.5%) nerves were bifurcated or trifurcated before the laryngeal entry point (LEP). More extralaryngeal branched RLNs were observed on the right side than on the left (17.5% vs. 13.3%, P = .294). The mean distance of the LEP point of division was longer on the left side (16.2 ± 6.7 mm) than on the right (14.7 ± 5.9 mm, P = .132). All branched RLNs had a palpable laryngeal twitch when stimulating anterior branches. When stimulating posterior branches, 28.2%(29/103) of branched RLNs showed palpable laryngeal twitch. Overall incidence of posterior motor branch in total RLNs was 4.3% (29/667).

CONCLUSIONS

The motor fibers of the RLN are all located in the anterior branch, whereas some posterior branches have motor function. Identification of all of the branches of the RLN may be mandatory to decrease the risk of postoperative nerve injury.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2678-2685, 2017.

Delayed bilateral vocal cord paresis after a continuous interscalene brachial plexus block and endotracheal intubation: A lesson why we should use low concentrated local anesthetics for continuous blocks

RATIONALE

Recurrent laryngeal nerve block is an uncommon complication that can occur after an interscalene brachial plexus block (ISB), which may lead to vocal cord palsy or paresis. However, if the recurrent laryngeal nerve is blocked in patients with a preexisting contralateral vocal cord palsy following neck surgery, this may lead to devastating acute respiratory failure. Thus, ISB is contraindicated in patients with contralateral vocal cord lesion. To the best of our knowledge, there are no reports of bilateral vocal cord paresis, which occurred after a continuous ISB and endotracheal intubation in a patient with no history of vocal cord injury or surgery of the neck.

PATIENT CONCERNS

A 59 year old woman was planned for open acromioplasty and rotator cuff repair under general anesthesia. General anesthesia was induced following an ISB using 0.2% ropivacaine and catheter insertion for postoperative pain control.

DIAGNOSES

While recovering in the postanesthesia care unit (PACU), however, the patient complained of a sore throat and hoarseness without respiratory insufficiency. On the morning of the first postoperative day, she still complained of mild dyspnea, dysphonia, and slight aspiration. She was subsequently diagnosed with bilateral vocal cord paresis following an endoscopic laryngoscopy examination.

INTERVENTIONS

The continuous ISB catheter was immediately removed and the dyspnea and hoarseness symptoms improved, although mild aspiration during drinking water was still present.

OUTCOMES

On the 4th postoperative day, a laryngoscopy examination revealed that the right vocal cord movement had returned to normal but that the left vocal cord paresis still remained.

LESSONS

When ISB is planned, a detailed history-taking and examination of the airway are essential for patient safety and we recommend that any local anesthetics be carefully injected under ultrasound guidance. We also recommend the use of low concentration of local anesthetics to avoid possible paralysis of the vocal cord.

The Non-Recurrent Laryngeal Nerve: a meta-analysis and clinical considerations

Background

The Non-Recurrent Laryngeal Nerve (NRLN) is a rare embryologically-derived variant of the Recurrent Laryngeal Nerve (RLN). The presence of an NRLN significantly increases the risk of iatrogenic injury and operative complications. Our aim was to provide a comprehensive meta-analysis of the overall prevalence of the NRLN, its origin, and its association with an aberrant subclavian artery.

Methods

Through March 2016, a database search was performed of PubMed, CNKI, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science. The references in the included articles were also extensively searched. At least two reviewers judged eligibility and assessed and extracted articles. MetaXL was used for analysis, with all pooled prevalence rates calculated using a random effects model. Heterogeneity among the included studies was assessed using the Chi² test and the I² statistic.

Results

Fifty-three studies (33,571 right RLNs) reported data on the prevalence of a right NRLN. The pooled prevalence estimate was 0.7% (95% CI [0.6–0.9]). The NRLN was found to originate from the vagus nerve at or above the laryngotracheal junction in 58.3% and below it in 41.7%. A right NRLN was associated with an aberrant subclavian artery in 86.7% of cases.

Conclusion

The NRLN is a rare yet very clinically relevant structure for surgeons and is associated with increased risk of iatrogenic injury, most often leading to temporary or permanent vocal cord paralysis. A thorough understanding of the prevalence, origin, and associated pathologies is vital for preventing injuries and complications.

Non-recurrent laryngeal nerve with a coexisting contralateral nerve demonstrating extralaryngeal branching

Non-recurrence and extralaryngeal branching are 2 of the more frequently encountered anomalies of the recurrent laryngeal nerve. If not anticipated intraoperatively, these abnormalities can put the nerve at risk, with subsequent vocal cord palsy. It is therefore important to report on and understand these abnormalities. We present a unique case of a non-recurrent laryngeal nerve with a coexisting contralateral nerve demonstrating extralaryngeal branching. This case allows us to demonstrate the importance of arteria lusoria in head and neck surgery, and to conclude that non-recurrence and extralaryngeal branching can occur separately within individual nerves in the same patient. The case also highlights the importance of a systematic intraoperative approach to the identification of every recurrent laryngeal nerve, especially in bilateral procedures having already exposed an anomalous nerve on one side.

Relationship of the recurrent laryngeal nerve to the inferior thyroid artery: A comparison of findings from two systematic reviews

Systematic reviews (SRs) of anatomical studies may include a meta-analysis (MA) that provides weighted averages as pooled estimates of prevalence. The relationship of the recurrent laryngeal nerve (RLN) to the inferior thyroid artery (ITA) or its branches has been assessed in two published SRs, one without MA of 32 studies (SR1) and the other with MA of 79 studies (SR2). Both SRs reported differences in RLN-ITA patterns (in three categories) by side of the body, but the anterior pattern was less frequent in SR1 vs. SR2. The aim of this review was to explain the differences. The unweighted data from SR1 were found to be more affected (vs. SR2) by a single study with the largest number of RLNs and a low proportion anterior. In a MA using data from SR1, the pooled prevalence estimate for the anterior pattern was substantial (35%) on the right side (vs. 15% on the left) and close to the findings published in SR2. These consistent findings should be relevant to surgeons in attempting to avoid iatrogenic injury to RLNs. Comparison of methods and results from two or more SRs on the same anatomical relationships may be useful in evidence-based anatomy. Clin. Anat. 30:318-321, 2017. © 2017 Wiley Periodicals, Inc.

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

Purpose. The aim of this meta-analysis was to provide a comprehensive evidence-based assessment, supplemented by cadaveric dissections, of the value of using the Ligament of Berry and Tracheoesophageal Groove as anatomical landmarks for identifying the Recurrent Laryngeal Nerve. Methods. Seven major databases were searched to identify studies for inclusion. Eligibility was judged by two reviewers. Suitable studies were identified and extracted. MetaXL was used for analysis. All pooled prevalence rates were calculated using a random effects model. Heterogeneity among included studies was assessed using the Chi² test and the I² statistic. Results. Sixteen studies (n = 2,470 nerves), including original cadaveric data, were analyzed for the BL/RLN relationship. The RLN was most often located superficial to the BL with a pooled prevalence estimate of 78.2% of nerves, followed by deep to the BL in 14.8%. Twenty-three studies (n = 5,970 nerves) examined the RLN/TEG relationship. The RLN was located inside the TEG in 63.7% (95% CI: 55.3-77.7) of sides. Conclusions. Both the BL and TEG are landmarks that can help surgeons provide patients with complication-free procedures. Our analysis showed that the BL is a more consistent anatomical landmark than the TEG, but it is necessary to use both to prevent iatrogenic RLN injuries during thyroidectomies.

The differential diagnosis of central compartment radioactive iodine uptake after thyroidectomy: anatomic and surgical considerations

OBJECTIVE

Foci of increased radioactive iodine (RAI) uptake in the thyroid bed following total thyroidectomy (TT) indicate residual thyroid tissue that may be benign or malignant. The use of postoperative RAI therapy in the form of remnant ablation, adjuvant therapy, or therapeutic intervention is often followed by a posttherapy scan. Our objective is to improve the clinician's understanding of the anatomic complexity of this region and to enhance the interpretation of postoperative scans.

METHODS

We conducted a comprehensive review of the literature evaluating RAI uptake in the central compartment following thyroid cancer treatment and literature related to anatomic nuances associated with this region. Thirty-eight articles were selected.

RESULTS

Through extensive surgical experience and a literature review, we identified the 5 most important anatomic considerations for clinicians to understand in the interpretation of foci of increased RAI uptake in the thyroid bed on a diagnostic scan: 1) residual benign thyroid tissue at the level of the posterior thyroid ligament, 2) residual benign thyroid tissue at the superior portion of the pyramidal lobe and/or superior poles of the lateral thyroid lobes, 3) residual benign thyroid tissue that was left attached to a parathyroid gland in order to preserve its vascularity, 4) ectopic benign thyroid tissue, and 5) malignant thyroid tissue that has metastasized to central compartment nodes or invaded visceral structures.

CONCLUSION

By correlating anatomic description, medical illustrations, surgical photos, and scans, we have attempted to clarify the reasons for foci of increased uptake following TT to improve the clinician's understanding of the anatomic complexity of this region.

Variaciones anatómicas del nervio laríngeo recurrente en una muestra de población colombiana

<p>Introducción. El nervio laríngeo recurrente (NLR), originado en el nervio vago, se encuentra relacionado con diferentes estructuras a nivel del tórax y del cuello, además de estar inmerso en diversos procesos nosológicos y quirúrgicos que pueden resultar en alteraciones funcionales; alteraciones que van desde la disfonía y la afonía hasta la muerte por obstrucción de la vía aérea. Estas complicaciones, específicamente las quirúrgicas, pueden cursar con secuelas permanentes del 0.3% al 3% de los casos y transitorias del 3% al 8%. Objetivo. Analizar el origen, el trayecto, los ramos y las relaciones anatómicas del nervio laríngeo recurrente en una muestra de 58 plastrones cervicocardiopulmonares y digestivos de población colombiana. Materiales y métodos. Estudio descriptivo analítico transversal con disección de 58 plastrones cervicocardiotorácicos seleccionados por muestreo a conveniencia. Resultados. Se determinó que el 100% de los plastrones disecados cuentan con un sitio de llegada usual; de igual modo, la descripción de la relación entre el NLR y la arteria tiroidea inferior (ATI) arrojó que la disposición más frecuente, tanto del NLR derecho como izquierdo, fue posterior a la ATI. Asimismo, se reportó el primer caso en Colombia y el décimo en el mundo del triángulo del nervio laríngeo recurrente (TNLR). Conclusiones. La disposición del NLR derecho e izquierdo es frecuentemente posterior a la ATI; de igual forma, es importante tener en cuenta la existencia del TNLR durante los abordajes quirúrgicos, especialmente en tiroidectomías.</p>

Confirmation of an anatomic variation of the recurrent laryngeal nerve at site of entry into the larynx in Chinese population

OBJECTIVE

This study was aimed at analyzing the frequency of the newly reported variation and the frequency of postoperative palsy associated with three different kinds of known variations.

METHODS

We conducted a retrospective study on the data of 2068 consecutive Chinese patients who underwent thyroidectomy. The study included 1362 left and 1507 right (2869 in total) RLNs.

RESULTS

Among all the RLNs, 548 were found to have variations at the laryngeal entry of the RLN. The most frequent variation was extralaryngeal branching (n=322), followed by the fan-shaped branching (n=201). Our newly identified variation was also noted in 25 of our patients. In these cases, the RLN entered the larynx from sites that were distant from the posterior cricothyroid joint. The distance from the entry of the RLN to the back of cricothyroid joints was over 5mm. Compared to the rates reported from other countries, the rate of the first type of variation is lower, while that of the second type is higher. The frequency of the new variation has not been reported in other populations, but it is consistent with our previous finding. The incidence of postoperative palsy was greater for RLNs with the first and third types of variations than in the normal RLNs.

CONCLUSION

We confirmed that the incidence of patients with the new type of variation of the RLN at the entry of the larynx was about 1% in Chinese. Awareness among surgeons regarding this variation is important to avoid postoperative palsy.

The Anatomical Relationship Between Recurrent Laryngeal Nerve and First Tracheal Ring in Males and Females

Objectives

Despite the modern advances in thyroid surgery, recurrent laryngeal nerve (rln) paralysis is still a critical problem. In order to decrease the rate of this complication, rln anatomy has been studied intensively. In our study, we aimed to recognize the relationship of rln and landmarks of the first tracheal ring.

Methods

Eighty-six female and 18 male patients who were undergone total thyroidectomy were included in this study. Trachea vertical height (tvh), right recurrent laryngeal nerve height (rrh), left recurrent laryngeal nerve height (lrh), right recurrent laryngeal nerve to trachea anterior face median raphe distance (rrd), left recurrent laryngeal nerve to trachea anterior face median raphe distance (lrd), right recurrent laryngeal nerve respect to trachea ratio (rrtr), and left recurrent laryngeal nerve respect to trachea ratio (lrtr) parameters of all patients were measured and compared in males and females using independent t-test and measurements on both right and left sides were compared statistically without sex discrimination.

Results

There were no significant differences between groups in tvh, rrh, rrd, lrd, rrtr, and lrtr parameters. Lrh parameter was significantly higher in males than in females (P<0.04). Comparison of right and left sides revealed that lrh was significantly higher than rrh (P<0.001), lrd was significantly higher than rrd (P<0.001), and rrtr was significantly higher than lrtr (P<0.001).

Conclusion

In this study, we have shown that in all cases the rln was located around the lower half of trachea vertical length and at this level left rln was located significantly deeper than the right side.

Extralaryngeal branching of the recurrent laryngeal nerve: a meta-analysis of 28,387 nerves

Introduction

The recurrent laryngeal nerves (RLN) are branches of the vagus nerve that go on to innervate most of the intrinsic muscles of the larynx. Historically, the RLN has been considered to branch after it enters the larynx, but numerous studies have demonstrated that it often branches before. The wide variability of this extralaryngeal branching (ELB) has significant implications for the risk of iatrogenic injury. We aimed to assess the anatomical characteristics of ELB comprehensively.

Methods

Articles on the ELB of the RLN were identified by a comprehensive database search. Relevant data were extracted and pooled into a meta-analysis of the prevalence of branching, branching pattern, distance of ELB point from the larynx, and presence of positive motor signals in anterior and posterior ELB branches.

Results

A total of 69 articles (n = 28,387 nerves) from both intraoperative and cadaveric modalities were included in the meta-analysis. The overall pooled prevalence of ELB was 60.0 % (95 % CI 52.0–67.7). Cadaveric and intraoperative subgroups differed with prevalence rates of 73.3 % (95 % CI 61.0–84.0) and 39.2 % (95 % CI 29.0–49.9), respectively. Cadavers most often presented with a ELB pattern of bifurcation, with a prevalence of 61.1 %, followed by no branching at 23.4 %. Branching of the RLN occurred most often at a distance of 1–2 cm (74.8 % of cases) prior to entering the larynx. A positive motor signal was most often noted in anterior RLN branches (99.9 %) but only in 1.5 % of posterior branches.

Conclusions

The anatomy of the RLN is highly variable, and ELB is likely to have been underreported in intraoperative studies. Because of its high likelihood, the possibility of ELB needs to be assessed in patients to prevent iatrogenic injury and long-term postoperative complications.

Electronic supplementary material

The online version of this article (doi:10.1007/s00423-016-1455-7) contains supplementary material, which is available to authorized users.

A Closer Look at the Recurrent Laryngeal Nerve Focusing on Branches & Diameters: A Prospective Cohort Study

AIM

We aimed to investigate the anatomical characteristics of the recurrent laryngeal nerve (RLN) highlighting on its diameter and branching pattern.

MATERIALS AND METHODS

We prospectively collected 215 patients (178 female, 37 male) who underwent thyroid/parathyroid surgery during over a 2-year period. Apart from demographic features and surgical data, diameter of RLNs, and their branches and as well as branching distance (distance between the point of bifurcation and the laryngeal entry of RLN) were recorded.

RESULTS

In 215 patients, 378 RLNs were assessed and 42% (n = 159) bifurcated RLNs were observed. The bifurcation rate was similar on the right and left side(s) of the neck (40% and 44%, respectively; p = 0.47). In those, who underwent bilateral exploration, in the case of bifurcation on the first side of the neck, the possibility of contralateral bifurcation was approximately 50%, whereas this rate was found to be only 30% in those with nonbranching RLNs. Mean branching distance was 18 ± 9 mm, and it was similar on the right and left sides (17 and 19 mm, respectively). Approximately 80% of bifurcations were observed within 5-24 mm of the RLN. Mean diameter of the anterior branches was found to be significantly larger compared to posterior branches (1.09 ± 0.35 and 0.82 ± 0.36 mm, respectively; p < 0.01).

CONCLUSIONS

There is great variability in RLN branching. We observed that approximately two out of three bifurcations were unilateral and anterior branches were thicker compared to posterior branches. These findings should be taken into consideration to avoid any damage to the RLN during thyroid and parathyroid surgery.

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

The recurrent laryngeal nerve (RLN) shows some anatomical variations that can potentially compromise the safety of thyroid surgery. The purpose of this prospective study was to identify the anatomical variations of the RLN in Chinese patients undergoing thyroid surgery. Between January 2007 and December 2013, 2,404 Chinese patients were hospitalized for thyroid surgery with dissecting of the RLN unilaterally or bilaterally. The patients consisted of 510 men and 1,894 women, with a median age of 45.0 years. Overall 3,275 RLNs, including 1,576 left- and 1,699 right-side nerves, were dissected. The anatomical variations were identified in 690 RLNs, including 305 left- and 385 right-side nerves. We identified as many as seven RLN anatomical variations in Chinese patients. These findings indicate that anatomical variations of the RLN are common, and the identification of these anatomical variations of the RLN can help to minimize the risk of post-operative RLN paralysis.

Motor function of the recurrent laryngeal nerve: Sometimes motor fibers are also located in the posterior branch

BACKGROUND

The function of the extralaryngeal branches of the recurrent laryngeal nerve (RLN) has yet to be described precisely. The goal of this study was to evaluate the incidence and motor function of the extralaryngeal branches of the RLN.

METHODS

Our study group consisted of 335 consecutive patients undergoing thyroid and parathyroid operations in whom the branches of the RLNs (n = 200) were evaluated with intraoperative nerve monitoring and by measuring the distance from the point of branching of the RLN into anterior and posterior branches and the entry of the individual branches into the larynx-defined as the branching distance. Anterior and posterior branches of the RLN were assessed separately by electromyography (using a standard electromyography endotracheal tube) for adduction and by finger palpation for abduction. The RLNs were classified as having motor function only in the anterior branches (Group 1) or function both in the anterior and posterior branches (Group 2).

RESULTS

There were 185 RLNs in Group 1 and 15 RLNs in Group 2, assessed by intraoperative nerve monitoring. Motor function was detected in all anterior branches of the RLN (100%) and in 8% of the posterior branches. The mean branching distance was greater in Group 2 compared with Group 1 (24.1 ± 13.6 mm, 17.3 ± 8.5 mm, respectively, P = .045).

CONCLUSION

Although the anterior branch of RLN always has motor function, the posterior branch also has motor function in about 8% of patients. The probability of detecting motor function in the posterior branch was greater among early branching RLNs, which have a greater branching distance. The surgeon should remember that posterior branches may contain motor fibers and protect these branches to avoid postoperative vocal cord dysfunction.

Recognition and Surgical Techniques for Management of Nonrecurrent Laryngeal Nerve during Carotid Endarterectomy

The presence of a nonrecurrent laryngeal nerve (NRLN) during carotid endarterectomy (CEA) may significantly limit the exposure of the surgical field during this operation. Although its reported incidence is rare, NRLN typically overlies the carotid bifurcation and failure to recognize this anatomic variation increases the risk of NRLN injury. A retrospective chart review of all patients who underwent CEA for hemodynamically significant extracranial carotid stenosis between January 2005 and December 2014 was performed. All patients with NRLN encountered intraoperatively were identified. Clinical outcomes, surgical techniques, and complications were reviewed and reported. Four left-sided NRLN were identified and 4 were right sided. No cranial nerve deficits or injuries occurred after CEA in patients where NRLN was encountered. Two distinct surgical techniques were used to manage patients with NRLN and they are discussed in detail.

Complications in thyroid surgery. Harmonic Scalpel, Harmonic Focus versus Conventional Hemostasis: A meta-analysis

BACKGROUND

To evaluate the incidence of postoperative complications, hemostatic effects and safety of Total Thyroidectomy (TT) performed using the Harmonic Scalpel (HS), the Harmonic Focus (HF) or Conventional Hemostasis (CH).

METHODS

The meta-analysis was performed according to PRISMA guidelines. A literature search was conducted from 2003 to 2014 and stringent criteria were required for inclusion. Thirteen studies concerning an overall population of 1458 compared HS versus CH, whilst 8 studies with 1667 patients compared HF versus CH.

RESULTS

There was a significant reduction of operative time (Mean Difference [MD] = -25.49 min.; 95% CI -32.43 to -18.55), intraoperative blood loss (MD = -30.49 mL; 95% CI -53.01 to -7.97), postoperative drainage volume (MD = -12.90 mL; 95% CI -22.83 to -2.98) and postoperative pain (MD = -0.87; 95% CI -1.27 to -0.46) in patients underwent TT with HS. Regarding HF group, a significant reduction of operative time (MD = -25.99 min., 95% CI -34.56 to -17.41), length of hospital stay (MD = -0.57; 95% CI -0.97 to -0.17), transient hypocalcemia (OR = 0.56; 95% CI 0.39 to 0.81) and postoperative pain (MD = -1.33 days; 95% CI -2.49 to -0.17) resulted.

CONCLUSIONS

HS TT can be a safe, useful and fast alternative to conventional TT. The newer HF can reduce the rate of hypocalcemia. Future RCTs of larger patient cohorts with more detailed data of postoperative complications, cost-effectiveness and cosmetic results, randomization procedures, intention-to-treat analyses and blinding of outcome assessors are needed to draw more meaningful conclusions.

Protection and Dissection of Recurrent Laryngeal Nerve in Salvage Thyroid Cancer Surgery to Patients with Insufficient Primary Operation Extent and Suspicious Residual Tumor

Some thyroid cancer patients undergone insufficient tumor removal in the primary surgery in China . our aim is to evaluate the impact of dissection of the recurrent laryngeal nerve during a salvage thyroid cancer operation in these patients to prevent nerve injury. Clinical data of 49 enrolled patients who received a salvage thyroid operation were retrospectively reviewed. Primary pathology was thyroid papillary cancer. The initial procedure performed included nodulectomy (20 patients), partial thyroidectomy (19 patients) and subtotal thyroidectomy (10 patients). The effect of dissection and protection of the recurrent laryngeal nerve and the mechanism of nerve injury were studied. The cervical courses of the recurrent laryngeal nerves were successfully dissected in all cases. Nerves were adherent to or involved by scars in 22 cases. Three were ligated near the place where the nerve entered the larynx, while another three were cut near the intersection of inferior thyroid artery with the recurrent laryngeal nerve. Light hoarseness occurred to four patients without a preoperative voice change. In conclusion, accurate primary diagnosis allows for a sufficient primary operation to be performed, avoiding insufficient tumor removal that requires a secondary surgery. The most important cause of nerve damage resulted from not identifying the recurrent laryngeal nerve during first surgery , and meticulous dissection during salvage surgery was the most efficient method to avoid nerve damage.

A systematic review of variations of the recurrent laryngeal nerve

With thyroid cancer fast becoming one of the most common endocrine cancers, the frequency of thyroid surgery has increased. A common and debilitating concern with thyroid surgery is recurrent laryngeal nerve (RLN) paralysis leading to glottal obstruction and airway compromise. A systematic review regarding the anatomical variation of the recurrent laryngeal nerve was performed to determine the position of anatomical variants of the RLN in relation to the inferior thyroid artery (ITA) as well as the prevalence of nonrecurrent laryngeal nerve (NRLN). MEDLINE, Web of Science, MEDITEXT, AMED, CINAHL, Cochrane, ProQuest, Pubmed, and ScienceDirect. Databases were searched using the search terms "inferior thyroid artery," "recurrent laryngeal nerve," "nonrecurrent laryngeal nerve," and "anatomical variation." The reference sections of the articles found were searched for additional reports. The references of all articles were searched to find articles missed in the database search. A total of 8,655 RLN sides were included in this study. One thousand eight hundred and thirteen (20.95%; 95% confidence interval (CI) 20.09, 2,182) showed a Type A configuration of RLN in relation to the ITA, 2,432 (28.10%; 95% CI 27.15, 29.06) showed a Type B configuration and 4,410 (50.95%; 95% CI 49.89, 52.01) showed a Type C configuration between the RLN and the ITA. The second search returned with 38,568 recurrent laryngeal sides and only 221 (0.57%; 95%CI 0.5, 0.65) NRLN documented. The RLN is most commonly found in the posterior position, relative to the ITA. The incidence of the NRLN is low, only occurring in 0.57% of people.

New variation of right recurrent laryngeal nerve: cases report

The recognition of variation in recurrent laryngeal nerves is important for both surgeons and the prognosis of patients undergoing surgery of the neck. Here, we reported a new variation of the right recurrent laryngeal nerves in five patients with thyroid surgery. The new variation is characterized by the additional ascending intracranial branches after division of laryngeal branches.

[Intraoperative avoidance and recognition of recurrent laryngeal nerve palsy in thyroid surgery]

Recurrent laryngeal nerve palsy is an intrinsic complication of thyroid surgery. Prevention of nerve palsy is considered to be a feature of quality in this very frequently performed operation. Risk factors and prevention strategies are demonstrated and discussed with reference to the current literature. Exact knowledge of the anatomy and possible variants of the track of the recurrent laryngeal nerve as well as its visualization and careful dissection are the cornerstones for nerve preservation. The use of intraoperative neuromonitoring allows preservation of the anatomical structure and functional integrity of the nerve and lesions which are not visible can be detected. Preconditions for correct interpretation are a standardized application and preoperative and postoperative laryngoscopy.

Routine exposure of recurrent laryngeal nerve in thyroid surgery can prevent nerve injury

To determine the value of dissecting the recurrent laryngeal nerve during thyroid surgery with respect to preventing recurrent laryngeal nerve injury, we retrospectively analyzed clinical data from 5 344 patients undergoing thyroidectomy. Among these cases, 548 underwent dissection of the recurrent laryngeal nerve, while 4 796 did not. There were 12 cases of recurrent laryngeal nerve injury following recurrent laryngeal nerve dissection (injury rate of 2.2%) and 512 cases of recurrent laryngeal nerve injury in those not undergoing nerve dissection (injury rate of 10.7%). This difference remained statistically significant between the two groups in terms of type of thyroid disease, type of surgery, and number of surgeries. Among the 548 cases undergoing recurrent laryngeal nerve dissection, 128 developed anatomical variations of the recurrent laryngeal nerve (incidence rate of 23.4%), but no recurrent laryngeal nerve injury was found. In addition, the incidence of recurrent laryngeal nerve injury was significantly lower in patients with the inferior parathyroid gland and middle thyroid veins used as landmarks for locating the recurrent laryngeal nerve compared with those with the entry of the recurrent laryngeal nerve into the larynx as a landmark. These findings indicate that anatomical variations of the recurrent laryngeal nerve are common, and that dissecting the recurrent laryngeal nerve during thyroid surgery is an effective means of preventing nerve injury.

Gender, race, and electrophysiologic characteristics of the branched recurrent laryngeal nerve

OBJECTIVES/HYPOTHESIS

The extralaryngeal branching of recurrent laryngeal nerves (RLN) conveys an increased risk of nerve injury during thyroid surgery. We hypothesized that racial and gender variations in prevalence of branched RLN exist.

STUDY DESIGN

A retrospective review of all patients who underwent thyroid surgery in a 4-year period in a single surgeon practice.

METHODS

The RLN was routinely identified during thyroid surgery. Presence of RLN branching, its distance from the laryngeal nerve entry point (NEP), and functionality of the branches were ascertained. Patient demographics, rates of neural branching, and distance of bifurcation from the NEP were evaluated using statistical analysis.

RESULTS

We identified 719 RLNs at risk in 491 patients who underwent central neck surgery. Four hundred and five (82.5%) patients were female and 86 (17.5%) patients were male. There were 218 (44.4%) African American patients and 251 (51.1 %) Caucasian patients. In African American patients, 42.1% RLNs bifurcated compared to 33.2% RLNs in Caucasian (P = 0.017) patients. The RLNs of African American and Caucasian patients bifurcated at comparable distances (P = 0.30). In male patients, 39.1% RLNs bifurcated; whereas in female patients 36.2% RLNs bifurcated (P = 0.53). On average, RLN bifurcation in female patients was at a longer distance from NEP compared to that of male patients (P = 0.012). Electrophysiologic testing found motor fibers in all anterior branches and three posterior extralaryngeal RLN branches.

CONCLUSION

African American patients have a higher rate of RLN bifurcation compared to Caucasian patients but no statistically significant difference in distance from NEP. Female patients tend to have longer branching variants of bifid RLNs. RLN motor fibers reside primarily in the anterior branch but may occur in the posterior branch.