Netrin-1 as A neural guidance protein in development and reinnervation of the larynx

Neural guidance proteins participate in motor neuron migration, axonal projection, and muscle fiber innervation during development. One of the guidance proteins that participates in axonal pathfinding is Netrin-1. Despite the well-known role of Netrin-1 in embryogenesis of central nervous tissue, it is still unclear how the expression of this guidance protein contributes to primary innervation of the periphery, as well as reinnervation. This is especially true in the larynx where Netrin-1 is upregulated within the intrinsic laryngeal muscles after nerve injury and where blocking of Netrin-1 alters the pattern of reinnervation of the intrinsic laryngeal muscles. Despite this consistent finding, it is unknown how Netrin-1 expression contributes to guidance of the axons towards the larynx. Improved knowledge of Netrin-1's role in nerve regeneration and reinnervation post-injury in comparison to its role in primary innervation during embryological development, may provide insights in the search for therapeutics to treat nerve injury. This paper reviews the known functions of Netrin-1 during the formation of the central nervous system and during cranial nerve primary innervation. It also describes the role of Netrin-1 in the formation of the larynx and during recurrent laryngeal reinnervation following nerve injury in the adult.

An institutional experience of intraoperative neurophysiological monitoring application in robotic thyroidectomy: a retrospective case-control study

Purpose

Intraoperative neurophysiological monitoring (IONM) has been introduced in thyroid surgery to prevent injury of the recurrent laryngeal nerve (RLN). However, its effectiveness remains controversial in robotic thyroidectomy (RT). This study aimed to compare the surgical outcome of RT in patients with and without the application of IONM.

Methods

This retrospective case-control study included 100 patients who underwent total thyroidectomy via robotic bilateral axillo-breast approach in a tertiary center. A study group of 50 patients who had IONM during RT was compared to a control group of 50 patients who underwent RT with nerve visualization alone.

Results

The sex ratio (4:45 vs. 7:43, P = 0.538), mean age (39.3 ± 7.1 years vs. 37.5 ± 10.4 years, P = 0.304), and body mass index (23.1 ± 2.6 kg/m2 vs. 22.2 ± 3.9 kg/m2, P = 0.215) were comparable between the IONM and control groups. Pathologic features including tumor size (0.8 cm vs. 0.9 cm, P = 0.283), extrathyroidal extension (58.0% vs. 24.0%, P = 0.316), lymph node metastasis (30% vs. 34%, P = 0.668), and number of lymph nodes (5.3 vs. 5.3, P = 0.668) showed no differences. There was no permanent RLN palsy, postoperative bleeding, and wound complications. Transient hypoparathyroidism was observed in 12 (24.0%) and 14 (28.0%), permanent hypoparathyroidism in 0 (0%) and 1 (2.0%), and transient RLN palsy was observed in 3 (6.0%) and 3 (6.0%), respectively.

Conclusion

We did not demonstrate a clear advantage of IONM in RT. Controversies regarding the effectiveness of IONM is not closed.

New strategy for intraoperative phonosurgical management of recurrent laryngeal nerve infiltrated by thyroid carcinoma

PURPOSE

Treating an infiltration of the recurrent laryngeal nerve (RLN) by thyroid carcinoma remains a subject of ongoing debate. Therefore, this study aims to provide a novel strategy for intraoperative phenosurgical management of RLN infiltrated by thyroid carcinoma.

METHODS

Forty-two patients with thyroid carcinoma infiltrating the RLN were recruited for this study and divided into three groups. Group A comprised six individuals with medullary thyroid cancer who underwent RLN resection and arytenoid adduction. Group B consisted of 29 differentiated thyroid cancer (DTC)patients who underwent RLN resection and ansa cervicalis (ACN)-to-RLN anastomosis. Group C included seven patients whose RLN was preserved.

RESULTS

The videostroboscopic analysis and voice assessment collectively indicated substantial improvements in voice quality for patients in Groups A and B one year post-surgery. Additionally, the shaving technique maintained a normal or near-normal voice in Group C one year post-surgery.

CONCLUSION

The new intraoperative phonosurgical strategy is as follows: Resection of the affected RLN and arytenoid adduction is required in cases of medullary or anaplastic carcinoma, regardless of preoperative RLN function. Suppose RLN is found infiltrated by well-differentiated thyroid cancer (WDTC) during surgery, and the RLN is preoperatively paralyzed, we recommend performing resection the involved RLN and ACN-to-RLN anastomosis immediately during surgery. If vocal folds exhibit normal mobility preoperatively, the MACIS scoring system is used to assess patient risk stratification. When the MACIS score > 6.99, resection of the involved RLN and immediate ACN-to-RLN anastomosis were performed. RLN preservation was limited to patients with MACIS scores ≤ 6.99.

A case of recurrent laryngeal nerve paralysis caused by radiofrequency ablation for mediastinal recurrence of lung cancer

Radiofrequency ablation (RFA) has emerged as a potent therapeutic modality for tumor treatment, and offers benefits such as reduced recovery time and minimal damage to nearby tissues. However, RFA is not devoid of complications, notably nerve damage during intrathoracic lesion treatments, which can significantly impact patients' quality of life. This report describes the unique case of a 71-year-old male who experienced hoarseness attributed to injury to the recurrent nerve after RFA for a locally recurrent lung cancer lesion in the mediastinum near the aortic arch. Although RFA has the advantages of a minimally invasive nature and positive outcomes, its risk of nerve injury, specifically in the thoracic region, highlights the need for improved techniques and preventive measures.

Varying Course of External Branch of Superior Laryngeal Nerve (EBSLN) and Recurrent Laryngeal Nerve (RLN) in Thyroidectomy-An Observational Study

Surgical management of a diseased thyroid depends on sonological and pathological evaluation and thereby, planning of the surgery. The definite surgery has two objectives: removal of the diseased gland and preservation of the nerves, namely EBSLN (External Branch of Superior Laryngeal Nerve) and RLN (Recurrent Laryngeal Nerve) and the Parathyroid glands. The objectives of the study were: (1) To identify the course of the RLN and EBSLN of both sides, during Thyroidectomy. (2) To discern various anatomical landmarks, the relations of the two nerves with them and anatomical variations, if any. In this Prospective observational study, fifty selected goitre patients underwent various types of thyroidectomies based on sonological and cytological criteria. The course and anatomical variations of EBSLN and RLN were photo-documented and results were analysed. Most of the EBSLN were found as Cernea type 1 type (25 out of 50), followed by Cernea type 2a (comprising 36%). The least common was type 2b. It was found that 36 out of 50 (72%) of RLN passed posterior to Inferior Thyroid Artery (ITA). Moreover, before piercing cricothyroid joint, the RLN showed bifurcation in 13 out of 50 subjects (26%), 1 participant had trifurcation and the remaining 36 (72%) had a single trunk. The EBSLN shows relation to the horizontal plane passing through the upper pole of the thyroid gland and it is more prone to get damaged when it passes within less than 1 cm to the plane. The RLN has various relations to the distinct anatomical landmarks thereby helping in safe dissection of the nerve. The study also noted the RLN in relation to ITA and branching before entering into the cricothyroid joint.

Utilizing Surgeon-Performed Intraoperative Translaryngeal Ultrasound for Verifying Vocal Fold Function: A Troubleshooting Approach for Intraoperative Neuromonitoring in Neck Surgery

INTRODUCTION

We investigated transcutaneous laryngeal ultrasonography (TLUS) for assessing vocal fold (VF) mobility during thyroid and parathyroid surgeries, emphasizing its precision and utility in signal loss scenarios.

METHODS

Between October 2020 and January 2023, we performed TLUS, Doppler sonography, laryngeal twitch response (LTR) palpation, and electromyography (EMG) to monitor recurrent laryngeal nerve function during neck surgeries. Postoperatively, the VF activity was verified using fiberoptic video laryngoscopy (FL). Concordance with FL was categorized based on VF activity.

RESULTS

Of the 443 VF evaluations, no instances of permanent bilateral paralysis were noted. Temporary unilateral palsy was found in 3.38% and permanent in 0.45%. TLUS displayed 97.8% agreement with EMG and was diagnostically superior (99.7% vs 98.2%) and more affordable ($68 vs $300) compared to analogous operative durations.

CONCLUSION

TLUS rivals EMG in terms of intraoperative neuromonitoring accuracy and outperforms LTR. Being cost-effective, TLUS can effectively address signal loss situations, thereby averting additional surgeries.

Cost-effectiveness of intraoperative neural monitoring of recurrent laryngeal nerves in thyroid lobectomy for papillary thyroid carcinoma

Purpose

Recurrent laryngeal nerve injury after thyroid surgery may cause vocal cord palsy (VCP), which leads to unexpected additional costs. In recent years, intraoperative neural monitoring (IONM) has been used to lower the incidence rate of VCP. This study aimed to analyze postoperative management costs for patients with papillary thyroid carcinoma (PTC).

Methods

We analyzed the medical records of patients who underwent lobectomy for PTC from September 2018 to August 2019 at The Catholic University of Korea, Seoul St. Mary's Hospital. A total of 411 patients were enrolled and all the patients had voice examinations. We investigated the total costs in the IONM and non-IONM groups during a maximum 1-year follow-up and calculated the additional costs due to VCP by subtraction of the mean values in each group.

Results

The incidence rate of VCP was 3.9% (16 of 411). Extrathyroidal extension was related to VCP in Cox regression tests and accounted for 3.2% (13 of 411). VCP rate did not show a significant difference between the IONM and non-IONM groups (4.1% vs. 3.8%, P = 0.883). Total costs for postoperative management were higher in the IONM group than in the non-IONM group (US $328.2 ± $220.1 vs. $278.7 ± $141.4, P < 0.05). However, the additional costs due to VCP were significantly lower in the IONM group than in the non-IONM group ($474.1 ± $150.3 vs. $568.9 ± $367.6, P < 0.005).

Conclusion

The use of IONM can mitigate the increase in costs by saving additional expenses associated with VCP.

Fluorescence imaging to visualize the recurrent laryngeal nerve during thyroidectomy procedures: analysis of 65 cases and 81 nerves

BACKGROUND

Recurrent laryngeal nerve (RLN) injury after thyroidectomy is relatively common. Locating the RLN prior to thyroid dissection is paramount to avoid injury. We developed a fluorescence imaging system that permits nerve autofluorescence. We aimed to determine the sensitivity and specificity of fluorescence imaging at detecting the RLN relative to thyroid and other background tissue and compared it to white light.

METHODS

In this prospective study, 65 patients underwent thyroidectomy from January to April 2022 (16 bilateral thyroid resections) using white and fluorescent light. Fluorescence intensity [relative fluorescence units (RFU)] was recorded for RLN, thyroid, and background. RFU mean, minimum, and maximum values were calculated using Image J software. Thirty randomly selected pairs of white and fluorescent light images were independently reviewed by two examiners to compare RLN detection rate, number of branches, and length and minimum width of nerves visualized. Parametric and nonparametric statistical analysis was performed.

RESULTS

All 81 RNLs observed were visualized more clearly under fluorescence (mean intensity, µ = 134.3 RFU) than either thyroid (µ = 33.7, p < 0.001) or background (µ = 14.4, p < 0.001). Forest plots revealed no overlap between RLN intensity and that of either other tissue. Sensitivity and specificity for RLN were 100%. All 30 RLNs and all 45 nerve branches were clearly visualized under fluorescence, versus 17 and 22, respectively, with white light (both p < 0.001). Visible nerve length was 2.5 × as great with fluorescence as with white light (µ = 1.90 vs. 0.76 cm, p < 0.001).

CONCLUSIONS

In 65 patients and 81 nerves, RLN detection was markedly and consistently enhanced with autofluorescence neuro-imaging during thyroidectomy, with 100% sensitivity and specificity.

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.

Anthracosis, a Distinct Cause of Vocal Fold Paralysis: Case Series

Vocal fold paralysis (VFP) can happen in various conditions due to mediastinal LADs, however no study has proposed anthracosis as an etiology. Here we discussed the chest CT features of anthracosis related LADs causing VFP. Among 41 cases of pulmonary anthracosis, 10 had VFP that all were presented with hoarseness. The paralysis was unilateral (left side) in all cases. Extra-nodal infiltration and conglomeration of lymph nodes were significantly higher in patients with paralysis. Left paratracheal, pre-vascular, and aortopulmonary window lymph nodes were seen in all patients. We propose that mediastinal LADs secondary to anthracosis could be a reason for left side VFP.

Usefulness of video laryngoscopy in tracheal intubation at thyroid surgical position for intraoperative neuromonitoring

This observational study aimed to compare the glottic view between video and direct laryngoscopy for tracheal intubation in the surgical position for thyroid surgery with intraoperative neuromonitoring. Patients scheduled for elective thyroid surgery with intraoperative neuromonitoring were enrolled. After the induction of anesthesia, patients were positioned in the thyroid surgical posture with a standard inclined pillow under their head and back. An investigator assessed the glottic view using the percentage of glottic opening (POGO) scale and the modified Cormack-Lehane grade in direct laryngoscopy and then video laryngoscopy sequentially while using the same McGRATH™ MAC video laryngoscope at once, with or without external laryngeal manipulation, at the surgical position. A total of thirty-nine patients were participated in this study. Without external laryngeal manipulation, the POGO scale significantly improved during video laryngoscopy compared to direct laryngoscopy in the thyroid surgical position (60.0 ± 38.2% vs. 22.4 ± 23.8%; mean difference (MD) 37.6%, 95% confidence interval (CI) = [29.1, 46.0], P < 0.001). Additionally, with external laryngeal manipulation, the POGO scale showed a significant improvement during video laryngoscopy compared to direct laryngoscopy (84.6 ± 22.9% vs. 58.0 ± 36.3%; MD 26.7%, 95% CI = [18.4, 35.0] (P < 0.001). The superiority of video laryngoscopy was also observed for the modified Cormack-Lehane grade. In conclusion, video laryngoscopy with the McGRATH™ MAC video laryngoscope, when compared to direct laryngoscopy with it, improved the glottic view during tracheal intubation in the thyroid surgical position. This enhancement may potentially facilitate the proper placement of the electromyography tracheal tube and prevent tube displacement due to positional change for thyroid surgery.

Avoiding Complications of Thyroidectomy: Recurrent Laryngeal Nerve and Superior Laryngeal Nerve Preservation

Both the superior and recurrent laryngeal nerves are at risk for injury during thyroid surgery. Comprehensive preoperative evaluation is key for surgical planning. Exposing nerves through careful dissection is the safest strategy to minimize injury risk. Intraoperative neural monitoring can be beneficial for both identifying and preserving the nerves.

Step-by-Step Thyroidectomy-Incision, Nerve Identification, Parathyroid Preservation, and Gland Removal

Thyroidectomy is a surgical procedure to remove part or all of the thyroid gland. Although the general tenets of surgery have remained the same, improvements in techniques, diagnostics, understanding of anatomy, and technology have allowed thyroid surgery to become a standard, effective, and safe surgery. For surgeons undertaking this procedure, it is imperative to have an in-depth knowledge of critical anatomy and a comprehensive understanding of surgical techniques to perform safe and effective surgery. This article aims to provide an overview of surgical techniques that may be applied in both benign and malignant disease settings.

The use of superior parathyroid gland as an anatomical landmark in identifying recurrent laryngeal nerve during total thyroidectomy: a prospective single-surgeon study

Purpose

This study was performed to determine the anatomical position of recurrent laryngeal nerve (RLN) relative to superior parathyroid gland (SPG) in a consecutive total thyroidectomy series.

Methods

A total of 421 patients (mean age, 45.6 years; female, 76.0%) who had total thyroidectomy accompanied with intraoperative exposure of RLN in relation to SPG were included in this prospective single-surgeon thyroidectomy series study. The relation of RLN to SPG was assessed based on the measurement of the natural distance between the RLN and SPG, which was categorized as 0-5 mm, 6-10 mm, and ≥11 mm.

Results

Most of the thyroidectomy indications (69.1%) were related to malignant disease including papillary carcinoma in 54.9% of cases. Overall, in 90.7% of patients RLN was identified within 5 mm of the SPG, and in 65.1% of cases, it was found within 1 mm of the SPG. The RLN was found between 6 and 10 mm from the SPG in 8.5% of cases, while it was at least 11 mm away from the SPG in 0.7% of cases.

Conclusion

In conclusion, this prospective single-surgeon thyroidectomy series study indicates the likelihood of localizing the RLN in close proximity to SPG during total thyroidectomy operations. Hence, the SPG can be used as a landmark to identify RLN, and as part of routine parathyroid-sparing thyroidectomy, it may represent a convenient complementary approach to minimize the risk of iatrogenic injury to RLN in patients with an intact SPG.

Ortner syndrome as a presenting symptom of severe chronic mitral regurgitation in heart failure: A case report

Ortner's syndrome or cardiovocal syndrome is a clinical condition associated with hoarseness due to left recurrent laryngeal nerve palsy from compression of surrounding cardiovascular structures. Atrial enlargement, commonly caused by chronic mitral regurgitation (MR) may be a source of compression. We present a case of a 53-year-old man with decompensated heart failure (HF) with a new onset of hoarseness. Chest radiograph showed cardiomegaly with evidence of fluid overload; transthoracic echocardiography showed bi-atrial enlargement secondary to severe chronic mitral regurgitation and moderate pulmonary hypertension. As a result, the diagnosis of Ortner's syndrome was made. For patients with new onset hoarseness with a history of severe cardiovascular disease, Ortner's syndrome should be considered and early initiation of therapy can help reduce the incidence.

Recurrent Laryngeal Nerve Monitoring: Nuts and Bolts

Intraoperative neuromonitoring (IONM) of the laryngeal nerves has become an important tool for neck endocrine surgery. In this article, the authors review the current evidence behind its use in neck endocrine procedures. The subtypes of IONM, including intermittent IONM, continuous vagal IONM (vagal-CIONM), and laryngeal adductor reflex CIONM, will be discussed. Finally, the authors review recent advances in IONM, and how standardization of outcomes reporting will help minimise conjecture regarding the usefulness of IONM.

Results of thyroidectomies according to general surgeons and otolaryngologist and cervico faciale surgeons at the general Hospital of Reference of Niamey, what differences in the protocols of management?

OBJECTIVE

To evaluate the surgical management of thyroid pathologies at the Reference General Hospital.

METHODS

This was a retro-prospective study over 4 years 6 months carried out in the departments of General and Digestive Surgery (GDS) and Otorhinolaryngology and Cervico Facial Surgery (ORL/FCS). It involved 182 patients who underwent thyroid surgery.

RESULTS

A frequency of thyroidectomy of 9.46% was found. Females predominated with a sex ratio of 0.1. The average age of patients was 42.85 years, a standard deviation 12.80. 84.06% of patients had consulted for anterior cervical mass. EU-TIRADS score 3 represented 7,14% of cases. Heteromultinodular goiter was the main indication for thyroid surgery (59.34%). Total thyroidectomy was the most commonly performed gesture in general surgery in 88,23% (n = 105), in Otorhinolaryngology, it was in the same proportion as lobo-isthmectomy at 47.61% (n = 30). The first route was video-assisted thyroidectomy 2.2% (n = 4). The recurrent laryngeal nerve was dissected and seen in 159 cases (87.36%) and parathyroid glands were also seen and preserved in 58.24% of cases (n = 106). In immediate postoperative surgery, the main complications were unilateral recurrent paralysis with dysphonia in 3.3% (n = 6) and compressive hematoma in 2.2% (n = 4). No deaths had been recorded.

CONCLUSION

Total thyroidectomy was the most performed procedure in department of General and Digestive Surgery. Routine oral calcium and vitamin D supplementation in the general surgery ward, reduces the occurrence of hypocalcemia after total thyroidectomy and allows a safe and early exit. Standardizing protocols will further reduce complications.

Voice Changes Without Laryngeal Nerve Alterations After Thyroidectomy: The Need For Prospective Trials - A Review Study

BACKGROUND

Thyroidectomy is a commonly performed surgical procedure that is offered for different thyroid pathologies. The most frequent complication after total thyroidectomy is transient or permanent hypoparathyroidism followed by transient or permanent recurrent laryngeal nerve palsy. Patients may experience voice impairment despite intact laryngeal nerve function. These patients are of special interest because they experience subjective symptoms which are difficult to measure and therefore to treat.

SUMMARY

The Voice Handicap Index (VHI) and VHI-10 are the most commonly used subjective questionnaires. Their results correlate with objective findings. Female sex, in particular after menopause, is a dominant factor for developing voice impairment after thyroidectomy. The extent of neck surgery and the weight and volume of the removed thyroid correlates directly with both objective and subjective voice impairment after surgery. Videolaryngostroboscopy should be considered to examine vocal cord pathologies in this patient group. Surprisingly, there are no studies showing that speech and voice therapy are beneficial for patients with voice alterations but with intact laryngeal nerves.

CONCLUSIONS

While recurrent laryngeal nerve (RLN) paralysis can be evaluated by objective exams postoperatively, we are still left with the issue of possible partial or complete external branch of superior laryngeal nerve (EBSLN) injury. It is therefore quite difficult to segregate neural (RLN and EBSLN) and non-neural voice change populations, regardless of the method of literature evaluation. Perhaps patients' perspectives on how they experience voice functionality should play a superior role in deciding which patients should be investigated further with laryngoscopy, acoustic or perceptual analysis, and which patients should be offered treatment.

Retrospective Cohort Study on the Surgical Outcomes of Intracapsular Thyroidectomy Vs Standard Thyroidectomy

The focal point of thyroidectomy surgery has always been to reduce the incidence of inadvertent damage to the recurrent laryngeal nerve(RLN). The intracapsular thyroidectomy is one such technique with minimum chance of injuring the nerve. To compare retrospectively the surgical outcomes between the two methods of thyroidectomy-coventional thyroidectomy Vs intracapsular thyroidectomy. Materials and methods-55 cases of benign thyroid disease for whom thyroidectomy was performed in our hospital between the period of 2019-2022 were compared retrospectively. Out of these 34 cases had undergone intracapsular thyroidectomy and 21 cases underwent routine extracapsular thyroidectomy. The surgical outcomes including operation time, pain, postoperative infection, postoperative hypocalcemia, postoperative recurrent laryngeal nerve paralysis and mean hospital stay were analyzed. The mean operating time were very low in the intracapsular limb as compared to the other group. The pain and the mean hospital stay was also far lesser for the intracapsular limb. Both cohorts had no incidence of hypocalcemia. The incidence of recurrent laryngeal nerve palsy was very low in the intracapsular cohort (only 1 case of temporary unilateral RLN palsy), whereas it was higher in the routine extracapsular cohort (5 cases of permanent palsy). The risk of having vocal cord palsy (left/right) is 1.172 times more with conventional/standard thyroidectomy as compared to intracapsular thyroidectomy. Intracapsular technique is a much more rewarding method to perform thyroidectomy, without the risk of the recurrent laryngeal nerve palsy as compared to routine thyroidectomy.

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.

Surgical Resection of Retrosternal Goitre: The Four-Finger Technique

Retrosternal goitre (RSG) is a thyroid gland with more than 50% of its mass located below the thoracic inlet. Pre-operative Computed Tomography can visualise the anatomical relations between the RSG and each mediastinal component, and the level of extension. Most cases of RSG can be resected via the cervical approach, as the thoracic approach carries a greater risk of complications. We describe a four finger technique for total thyroidectomy in five cases of RSG through a neck incision, without the need for a sternotomy. The recurrent laryngeal nerve (RLN) was identified early in the Baehr's triangle. The thyroid was mobilised in the neck by ligation of the feeding vessels and separated from the tracheal attachments. The retrosternal portion was then delivered into the neck by blunt dissection, keeping two fingers of each hand close to the thyroid gland. The RLN and parathyroids were identified early in the surgery to avoid the complications of hoarseness and hypoalcemia, respectively.

Shaving Papillary Thyroid Carcinoma Involving Functioning Recurrent Laryngeal Nerve: Safety of Incomplete Tumor Resection and Nerve Sparing

BACKGROUND

Whether to sacrifice or spare the recurrent laryngeal nerve (RLN) when papillary thyroid carcinoma (PTC) involves a functioning RLN remains controversial. Oncological outcomes after shaving PTC with gross remnant on the RLN have been rarely reported. The objective of this study was to evaluate the oncological outcomes of patients who underwent shaving of a PTC from the RLN, leaving a gross residual tumor with the intent of vocal function preservation.

METHODS

A retrospective, cohort study was conducted in 47 patients who were determined to have PTC invasion of the RLN via intraoperative inspection and underwent tumor shaving with macroscopic remnant (R2 resection) less than 1 cm in length and 4 mm in thickness. Median follow-up period was 93 (range, 60-215) months. The primary endpoint was the recurrence-free survival and the progression-free survival. Secondary endpoints were biochemical outcomes (serum thyroglobulin) and vocal cord function.

RESULTS

Of the 47 patients, five (10.6%) patients showed recurrence (central neck, 3; lateral neck, 2) without death or distant metastasis. The RLN was resected along with the tumor in one (2.1%) patient who presented with progression of the residual tumor. Postoperative temporary vocal cord paralysis occurred in six (12.8%) patients without permanent cases. The final nonstimulated serum thyroglobulin was 0.7 ± 1.8 ng/ml.

CONCLUSIONS

Shaving a tumor from a RLN with gross residual disease may be considered an alternative strategy to preserve vocal function when complete tumor resection with nerve preservation is impossible in patients with PTC invading a functioning RLN.

Comparison of intraoperative neural monitoring between endoscopic transoral and bilateral axillo-breast approach thyroidectomy

BACKGROUND

The use of intraoperative neuromonitoring (IONM) during endoscopic thyroidectomy has not been fully explored, with limited studies focusing solely on the recurrent laryngeal nerve (RLN) and neglecting the external branch of the superior laryngeal nerve (EBSLN). This study aimed to compare the effectiveness of IONM in two endoscopic thyroidectomy techniques, namely the transoral and bilateral axillo-breast approach (BABA).

METHODS

We retrospectively reviewed patients who underwent endoscopic thyroidectomy with IONM and compared the outcomes between those who underwent different surgical techniques (transoral or BABA). We recorded the detection method and identification rate of the EBSLN and RLN, along with the amplitude and latency of the evoked potential.

RESULTS

We monitored 98 nerves at risk (NAR) from 74 patients (60 and 38 in the transoral and BABA groups, respectively). Almost all EBSLNs were identified using electromyography (EMG) signals and/or cricothyroid muscle twitches, except for one patient in the transoral group who developed EBSLN palsy. Patients in the transoral group were more likely to have the sternothyroid muscle divided (75.0% vs. 15.8%, p < 0.001) and had a lower rate of visual recognition of the EBSLN fibers (10.0% vs. 31.6%, p = 0.007) than did those in the BABA group. All RLNs were identified in both groups; however, patients in the BABA group had a relatively higher rate of post-dissection amplitude reduction > 50% (15.8% vs. 5.0%, p = 0.072), and one patient had transient RLN palsy.

CONCLUSIONS

Both the EBSLN and RLN could be adequately identified and monitored during endoscopic transoral and BABA thyroidectomies using IONM.

Intraoperative Nerve Monitoring during Minimally Invasive Esophagectomy and 3-Field Lymphadenectomy: Safety, Efficacy, and Feasibility

Background

The objective of this study was to demonstrate the safety, efficacy, and feasibility of intraoperative monitoring of the recurrent laryngeal nerves during thoracoscopic and robotic 3-field esophagectomy.

Methods

This retrospective analysis details our initial experience using intraoperative nerve monitoring (IONM) during minimally invasive 3-field esophagectomy. Data were obtained from a prospectively maintained database and electronic medical records. The study included all patients who underwent minimally invasive (video-assisted thoracic surgery/robotic) transthoracic esophagectomy with neck anastomosis. The patients were divided into those who underwent IONM during the study period and a historical cohort who underwent 3-field esophagectomy without IONM at the same institution. Appropriate statistical tests were used to compare the 2 groups.

Results

Twenty-four patients underwent nerve monitoring during minimally invasive 3-field esophagectomy. Of these, 15 patients underwent thoraco-laparoscopic operation, while 9 received a robot-assisted procedure. In the immediate postoperative period, 8 of 24 patients (33.3%) experienced vocal cord paralysis. Relative to a historical cohort from the same institution, who were treated with surgery without nerve monitoring in the preceding 5 years, a 26% reduction was observed in the nerve paralysis rate (p=0.08). On follow-up, 6 of the 8 patients with vocal cord paralysis reported a return to normal vocal function. Additionally, patients who underwent IONM exhibited a higher nodal yield and a decreased frequency of tracheostomy and bronchoscopy.

Conclusion

The use of IONM during minimally invasive 3-field esophagectomy is safe and feasible. This technique has the potential to decrease the incidence of recurrent nerve palsy and increase nodal yield.

Intra Operative Recurrent Laryngeal Nerve Monitering During Thyroid Surgery - Is It Worth?

The basic principle of head and neck surgery is based on the identification and preservation of important structures, rather than avoidance. Thyroid surgeries are the most frequently performed endocrine procedures worldwide. Recurrent laryngeal nerve (RLN) palsy after thyroid surgery is a serious postoperative complication that can diminish the quality of life. While it is generally accepted that direct visualisation of the nerve is the gold standard, intraoperative nerve monitoring (IONM) is being used increasingly as an adjuvant to help identify the nerve. This study was carried out in Mahatma Gandhi medical college and hospital, Jaipur, Rajasthan from June 2018 to March 2020. 100 patients were enrolled in the study. RLN is identified & visualized in Beahr's triangle or in Lore's triangle. We have randomly selected the patient and use IONM as an adjunct to standard visual identification of the recurrent laryngeal nerve (RLN) to prevent nerve lesion. 8 out of 108 nerves which were at risk during thyroid surgery were found injured. 2 of 50 (4%) nerves at risk were injured with IONM that caused temporary paresis. Without IONM, 5 of 58 (8.6%) nerves at risk suffered temporary paresis and 1of 58(1.72%) had paralysis. Visual nerve identification alone remains the gold standard of recurrent laryngeal nerve management in thyroid surgery and one can use operating microscope for magnification. Neuromonitoring helps to identify the RLN particularly in difficult cases, but it does not decrease the injury to RLN as compared to visualization alone.

Vocal cord paralysis associated with pleuroparenchymal fibroelastosis: A case report and literature review

Here, we report a case of idiopathic pleuroparenchymal fibroelastosis (PPFE) that progressed to pulmonary aspergilloma, aspiration pneumonia, and left vocal cord paralysis (VCP). To date, five cases of PPFE with VCP have been reported, including the present case. Aspiration pneumonia occurred in three cases, leading to death in two cases. Four cases had left-sided paralysis, in two of which, the paralysis occurred on side opposite to the predominant side (right side) of PPFE. Structural mechanisms underlying the recurrent laryngeal nerve could be involved. This report may further highlight the existence of hoarseness and dysphagia in PPFE.

Analysis of the Outcomes of Immediate Recurrent Laryngeal Nerve Reconstruction During Thyroid Surgery for Prevention of Vocal Fold Paralysis

BACKGROUND

Recurrent laryngeal nerve (RLN) injury and the resulting paralysis is the most common and known complication of thyroid surgery. Several surgical techniques, such as medialization thyroplasty with or without arytenoid adduction and injection laryngoplasty, have been developed to treat RLN injury, but these procedures have specific limitations and complications. In this study, we present the outcomes for our patients who underwent immediate RLN reconstruction during thyroid surgery by analyzing both subjective and objective outcomes.

METHODS

A retrospective study was conducted for patients who underwent total or subtotal thyroidectomy between May 2012 and March 2020. Among them, patients who underwent immediate RLN reconstruction due to unilateral RLN injury were followed for at least 12 months. The voice perceptual evaluation, acoustic analysis, voice range profile, and Voice Handicap Index (VHI) scores were obtained preoperatively, 1 month, 6 months, and 12 months after surgery.

RESULTS

Among the 11 patients, 6 patients (54.5%) underwent direct anastomosis, and 5 patients (45.5%) underwent nerve grafts using ansa cervicalis and great auricular nerve. The grade and breathiness in the GRBAS (grade, roughness, breathiness, asthenia, and strain) scale and jitter item showed significant improvement at 12 months postoperatively, and although not statistically significant, the rest of the items also tended to improve. The total, functional, and physical scores on VHI improved significantly at 12 months postoperatively. Moreover, when comparing the voice analysis of the direct anastomosis group and the nerve graft group, there was no significant difference between the groups in objective and subjective results.

CONCLUSION

Immediate RLN reconstruction demonstrated significant voice improvement postoperatively, and reconstructing the nerve immediately and combining follow-up treatment in the event of RLN injury will greatly help patients improve their long-term voice outcomes.

Recurrent laryngeal nerve's course running anteriorly to a thyroid tumor

The thyroid gland's neurovascular relationship is commonly portrayed as the recurrent laryngeal nerve (RLN) coursing posteriorly to the thyroid gland. We report a rare case with the RLN running anteriorly to a thyroid tumor. A 56-year-old Japanese woman underwent a thyroidectomy for a benign thyroid tumor. Preoperatively, computed tomography confirmed that part of the tumor had extended into the mediastinum and was descending posteriorly up to the brachiocephalic artery. Intraoperatively, when the sternothyroid muscle was incised to expose the thyroid gland, a cord (nerve)-like structure was observed directly anterior to the thyroid tumor. Although the course of this cord-like structure was clearly different from the "traditional" course of the right RLN, the possibility that the structure was the RLN could not be excluded. The structure was traced back in order to preserve it; we saw that it entered the larynx at the lower margin of the cricothyroid muscle and approximately at the level of the cricothyroid junction through the back of the normal thyroid tissue. With intraoperative neuromonitoring, the structure was identified as the RLN. As a result, the course of the RLN run anterior to the tumor but then posterior to the 'normal thyroid' i.e. into it normal anatomical position. Had we assumed that the RLN was behind the thyroid tumor, we would have damaged the RLN. It would not be possible to diagnose this abnormal running course of the RLN reliably before surgery, but extra care should be taken in similar cases, that is, when a large thyroid tumor is descending posteriorly up to the brachiocephalic artery on the right side.

Left Vocal Cord Paralysis in Idiopathic Pleuroparenchymal Fibroelastosis: A Case Report

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease that is characterized by predominant upper lobe fibrosis and pleural thickening. In this report, we present an unusual case of idiopathic PPFE with left vocal cord paralysis that developed repeated aspiration pneumonia. Vocal cord paralysis is a rare complication of PPFE, and two mechanisms can be proposed: 1) Fibrous adhesion of the recurrent laryngeal nerve to the chest wall can cause stretching of the nerve. 2) Traction or compression of the recurrent laryngeal nerve due to the distortion of the tracheobronchial tree can cause paralysis of the vocal cord. Finally, to reduce the risk of aspiration pneumonia, laryngoscopic evaluation of the vocal cord is recommended in patients with PPFE with hoarseness and dysphagia for early intervention.

Histological study of the thin membranous dense connective tissues around the curving portion of the bilateral recurrent laryngeal nerves

OBJECTIVE/AIM

We aimed to demonstrate the anatomical relationship between the recurrent laryngeal nerves (RLNs), thin membranous dense connective tissue (TMDCT [e.g., the visceral or vascular sheaths around the esophagus]), and the lymph nodes around the esophagus at the curving portion of the RLNs for rational and efficient lymph node dissection.

METHODS

Transverse sections of the mediastinum at 5 mm or 1 mm intervals were obtained from four cadavers. Hematoxylin and eosin staining and Elastica van Gieson staining were performed.

RESULTS

The visceral sheaths could not be clearly observed the curving portions of the bilateral RLNs, which were observed on the cranial and medial side of the great vessels (aortic arch and right subclavian artery [SCA]). The vascular sheaths could be clearly observed. The bilateral RLNs diverged from the bilateral vagus nerves, which ran along with the vascular sheaths, went up around the caudal side of the great vessels and the vascular sheath, and ran cranially on the medial side of the visceral sheath. Visceral sheaths were not observed around the region containing the left tracheobronchial lymph nodes (No. 106tbL) or the right recurrent nerve lymph nodes (No. 106recR). The regions containing the left recurrent nerve lymph nodes (No. 106recL) and the right cervical paraesophageal lymph nodes (No. 101R) were observed on the medial side of the visceral sheath, with the RLN.

CONCLUSION

The recurrent nerve, which branched off from the vagus nerve descending along the vascular sheath, ascended the medial side of the visceral sheath after inversion. However, no clear visceral sheath could be identified in the inverted area. Therefore, during radical esophagectomy, the visceral sheath along No. 101R or 106recL may be recognized and available.

Machine learning to predict occult metastatic lymph nodes along the recurrent laryngeal nerves in thoracic esophageal squamous cell carcinoma

PURPOSE

Esophageal squamous cell carcinoma (ESCC) metastasizes in an unpredictable fashion to adjacent lymph nodes, including those along the recurrent laryngeal nerves (RLNs). This study is to apply machine learning (ML) for prediction of RLN node metastasis in ESCC.

METHODS

The dataset contained 3352 surgically treated ESCC patients whose RLN lymph nodes were removed and pathologically evaluated. Using their baseline and pathological features, ML models were established to predict RLN node metastasis on each side with or without the node status of the contralateral side. Models were trained to achieve at least 90% negative predictive value (NPV) in fivefold cross-validation. The importance of each feature was measured by the permutation score.

RESULTS

Tumor metastases were found in 17.0% RLN lymph nodes on the right and 10.8% on the left. In both tasks, the performance of each model was comparable, with a mean area under the curve ranging from 0.731 to 0.739 (without contralateral RLN node status) and from 0.744 to 0.748 (with contralateral status). All models showed approximately 90% NPV scores, suggesting proper generalizability. The pathology status of chest paraesophgeal nodes and tumor depth had the highest impacts on the risk of RLN node metastasis in both models.

CONCLUSION

This study demonstrated the feasibility of ML in predicting RLN node metastasis in ESCC. These models may potentially be used intraoperatively to spare RLN node dissection in low-risk patients, thereby minimizing adverse events associated with RLN injuries.

A New Anatomical Variation and Course of RLN Described: A Rare Case Report of a Lateral and Superiorly Placed Bilateral RLN Over the Thyrohyoid Muscle

Ling XY described 3 variations of RLN in relation to Inferior thyroid artery (ITA), with the RLN either being anterior to ITA, in between the branches of ITA or posterior to ITA. We add to these variations and present a new anatomical variation and course of RLN in which it lies in a lateral position and descends from a superior position on the thyrohyoid muscle to enter the larynx medially.

Comparative Study of Parathyroid Identification Techniques Using Zuckerkandl's Tubercle Versus Parathyroid Arterial Supply as Intra-Operative Markers

Thyroid surgeons should be able to identify factors that prevent parathyroid damage. The aim of the study was (i) to compare the effectiveness of using Zuckerkandl's Tubercle (ZT) versus superior thyroid artery (STA) and inferior parathyroid artery (ITA) as markers for identification of superior and inferior parathyroid glands and (ii) to demonstrate a series of detailed, logical and orderly operative steps to identify ZT during thyroidectomy operation. This 1-year prospective observational study was carried out in the Department of Otolaryngology in a tertiary medical institute. Out of 36 cases of thyroidectomy, parathyroid identification in Group A was based on STA and ITA and in Group B was based on ZT. The surgical steps, parathyroid location, preservation and its anatomical relations were noted. The mean age in Group A and Group B was 38.8 years and 44.9 years respectively with 77.4 and 62.5% SPT identified above the intersection of RLN and ITA respectively. On left side 62.5% SPT were  located at 2 o'clock position and 50% at 10 o'clock location in right side. In Group A, 60.7% of IPT glands were related close to ITA while in Group B it was 44.4%. Group B reported a higher rate of successful identification and preservation (93.75%). ZT greatly improved the reliability for localising and preserving the parathyroid glands during thyroidectomy. SPT is usually found to lie cranial to ZT, above the intersection of RLN & ITA and behind RLN whereas IPT is variable and lies below the intersection.

Factors Associated With Injury to Recurrent Laryngeal Nerve in Patients Undergoing Surgery for Thyroid Cancer: A Single-centre Study Using Translaryngeal Ultrasound

AIMS

Intraoperative injury to the recurrent laryngeal nerve (RLN) is a serious complication occurring more frequently in patients with thyroid cancer than in those with benign thyroid diseases. However, data on the risk factors for RLN injury among patients with thyroid cancer are scarce. Currently, RLN injury is diagnosed by laryngoscopy, but translaryngealultrasonography (TLUS), which is less invasive, appears to have a similar accuracy. Herein, we analysed risk factors ofintraoperative RLN injury in patients with thyroid cancer and assessed the diagnostic performance of TLUS.

PATIENTS AND METHODS

In this prospective study, we enrolled patients undergoing surgery for thyroid cancer from October 2020 to October 2021. Medical and surgical variables were analysed as risk factors of RLN injury. TLUS was compared with laryngoscopy in diagnosing RLN injury.

RESULTS

There were 185 patients who underwent 196 surgeries. Of all surgeries, 23 (11.7%) caused RLN injury ascertained on laryngoscopy. Compared with laryngoscopy, TLUS displayed high sensitivity (97.7%; 95%CI: 94.3%-99.4%) and specificity (100%; 95% CI: 82.4%-100%). Before surgery, medical and surgical characteristics did not differ significantly between patients with or without RLN injury, but RLN entrapment by tumour was more frequent in those with the injury (P < 0.001). The risk of RLN injury was increased in patients undergoing thyroidectomy with lateral neck dissection (OR = 4.53; 95% CI: 1.29-14.32) and in those with lymph node metastases (OR = 2.76; 95% CI: 1.03-7.01).

CONCLUSION

Intraoperative RLN injury in patients with thyroid cancer is more common after operations requiringgreater resections and with lymph node involvement. TLUS could be used to diagnose RLN injury.

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.

Giant Parathyroid Adenoma: Are They Different?

Primary hyperparathyroidism is a common endocrinology anomaly which involves head and neck region. The diagnosis and treatment of parathyroid adenoma however still remains a challenge. Giant parathyroid adenomas are rare and involve more surgical expertise. Retrospective study was carried in Departments of ENT and Endocrinology, SMS Medical College and Hospital, Jaipur. Records of patients operated between 2010 and 2019 were evaluated and analysed for size and site of parathyroid adenomas, biochemical parameters, intra-operative findings and postoperative course. Tumours with size > 3 cm were termed as giant parathyroid adenomas and this is a rarity in literature. Records of 79 patients were found to be complete. Out of these 9 had giant parathyroid adenomas: 4 left inferior, 2 right inferior, 1 ectopic location (superior mediastinum) and 1 each in left and right superior glands. The size, symptomatology and biochemical parameters are discussed in light of available literature. Giant parathyroid adenomas are a rare entity and their behaviour are same as of non giant parathyroid adenomas. In the view of literature published on pub Med, this is found to be largest case series on parathyroid Adenoma considering size more than 3 cm.

An Audit of the Procedure of Open Thyroidectomy at A Tertiary Care Centre

We plan to evaluate the various variables associated with the complications of thyroidectomy performed at our department in the last 5 years. Medical records of the patients who underwent thyroidectomy during 2014-2018 were collected. Complications of hypocalcemia and recurrent laryngeal nerve palsy were analysed in terms of the demography, cytopathology and the extent of surgery. Student's t-test, Mann-Whitney U-test, Fisher exact test and chi square test were applied to look for any significant associations. P value < 0.05 was considered significant. 123 patients were analysed (87 females, 38 males). Mean age was 38.3 years (range 11-71 years). Most common cytopathology was papillary carcinoma thyroid (Bethesda VI) - 43/123 (35%). 107 of these 123 patients underwent primary surgery, 10 underwent revision surgery while 6 underwent completion thyroidectomy. Seven patients incurred RLN palsy out of which 3 were temporary. RLN palsy was seen in only malignant cases (p < 0.05). Incidence was higher in T4a stage (p < 0.05). However, it had no association with a simultaneous central or lateral neck dissection. Hypocalcemia was seen in 22 patients (17.8%), out of whom 9 patients developed permanent hypocalcemia. It was seen significantly higher in patients undergoing central neck dissection (p < 0.05) and in malignant thyroid lesions (p < 0.05). Gender, age and the cytopathology had no bearing on RLN palsy and hypoparathyroidism. Malignant thyroid lesions had a significantly higher incidence of RLN palsy and hypoparathyroidism. A thorough anatomical knowledge can reduce the incidence of these complications.

Is craniocaudal dissection of recurrent laryngeal nerve safer than lateral approach: a prospective randomized study comparing both techniques by using continuous intraoperative nerve monitoring

Purpose

This study was performed to compare the real-time electromyographic (EMG) changes and the rate of recurrent laryngeal nerve (RLN) injury in craniocaudal and lateral approaches for RLN during thyroidectomy.

Methods

One hundred twelve and 86 patients were prospectively randomized to receive lateral (group 1) or craniocaudal (group 2) approach to RLN, respectively, under continuous intraoperative nerve monitoring.

Results

Loss of signal (LOS) occurred in 7 (2.0%) of 356 nerves at risk (NAR). LOS was significantly associated with repeated adverse EMG changes and presence of RLN entrapment at the ligament of Berry (LOB), which was accompanied by other clinicopathological or anatomical features, such as tubercle of Zuckerkandl (TZ), extralaryngeal branching, hyperthyroidism, autoimmune thyroid disease (ATD), or thyroid lobe volume of >29 cm³ (P = 0.001 and P = 0.030, respectively). The rate of repeated adverse EMG changes and LOS in the NARs with LOB entrapment accompanied by other clinicopathological and anatomical features was higher in group 1 vs. group 2 (11.1% vs. 2.2%, respectively and 9.7% vs. 0%, respectively; P = 0.070). The total rate of vocal cord palsy (VCP) was significantly higher in group 1 than in group 2 (P = 0.005). The rate of permanent VCP showed no significant difference between the 2 groups.

Conclusion

The craniocaudal approach to the RLN is safer than the lateral approach in the RLNs with entrapment at the LOB accompanied by other features, such as TZ, extralaryngeal branching, hyperthyroidism, ATD, or high thyroid lobe volume.

Risk factors for difficult thyroidectomy and postoperative morbidity do not match: retrospective study from an endocrine surgery academic referral centre

Hyperthyroidism, goiter and thyroiditis have been associated with complex thyroidectomy. Difficult thyroidectomies may implicate longer operating times and higher complication rates, while literature on quantification and prediction of difficulty in thyroidectomy is scant. We aim at assessing the impact of preoperative and intraoperative factors on the technical difficulty of total thyroidectomy (TT) and on the incidence of postoperative complications. We conducted a retrospective study on 197 TT from 343 thyroidectomies performed with intraoperative neuromonitoring between October 2019 and June 2022 (excluding lobectomies, nodal dissection, extra-thyroidal procedures). Operating time (surrogate of TT difficulty), postoperative hypocalcaemia, recurrent laryngeal nerve palsy and postoperative bleeding were assessed in relation to pre- and intraoperative characteristics. Vocal fold palsy(VFP) was defined as recovering < 12 months postoperatively. There were 87 thyroid cancers and 110 multinodular goiters (21 hyperfunctioning, 51 mediastinal). Median operating time was 136 min (range 51-310). Within 17.4 months overall median follow-up we recorded two transient VFPs and 12% symptomatic transient hypocalcaemia. At univariable analysis male sex (p = 0.005), BMI (p < 0.001), thyroiditis (p < 0.05), hypervascular goiter (p = 0.003) and thyroid adhesions to surrounding anatomical structures (p < 0.001) were associated with longer operating time. At multivariable analysis male male sex (p = 0.01), obesity (p = 0.001) and thyroid adhesions (p = 0.008) were factors for prolonged operating time. Above-normal anti-thyroid peroxidase antibodies correlated to transient symptomatic hypocalcemia (p < 0.001). Risk factors for complex TT were identified and did not correlate with morbidity rates. Results from this study may help optimizing operating room schedule and inform case selection criteria for training programs in thyroid surgery. Further research is required to confirm these findings.

The learning curve and safety of continuous intraoperative vagus nerve monitoring in thyroid surgery

INTRODUCTION

Continuous intraoperative nerve monitoring allows for continuous feedback on the integrity of the recurrent laryngeal nerve (RLN) and the quality of its induced myogenic potential. The aims of this study were to assess the time requirements and risks associated with vagus nerve electrode placement when learning the technique.

METHODS

This is a prospective observational study carried out in a single otolaryngology department at the start of a trainee's placement. A total of 40 vagus nerve dissections in 31 consecutive operations (22 hemithyroidectomies, 9 total thyroidectomies) using automatic periodic stimulation (APS, Medtronic) are included. Of the electrode placements, 10 were performed by the trainer and 30 by the trainee. The time required for each surgical step and complications relating to vagus nerve dissection were recorded.

RESULTS

The average (median+IQR) total additional time attributable to vagus nerve dissection, electrode placement and baseline electromyogenic assessment was 3.1mins (2.5-3.3) for the trainer and 4.8mins (4.1-5.3) for the trainee (p<0.0001). There was a downward trend in time requirement for the trainee (not statistically significant, p=0.080). Total operative time was 38min (35-45) for hemithyroidectomy and 56min (53-62) for total thyroidectomy. There was a mix of benign (74%) and malignant (26%) histology, no intraoperative complications relating to autonomic dysfunction and one (2.5%) transient nerve palsy.

CONCLUSIONS

Operative time attributable to vagus nerve electrode placement is short and the procedure is easy to learn. Appropriate surgical technique and careful anaesthetic considerations allow monitoring to be performed safely, and may reduce the rate of RLN palsy.

Intra-operative nerve monitoring and recurrent laryngeal nerve injury during thyroid surgery: a network meta-analysis of prospective studies

PURPOSE

Recurrent laryngeal nerve (RLN) injury is a feared complication of thyroid surgery occurring in 1-5% of cases. The present approaches to RLN preservation include RLN visualization with no nerve monitoring (No-NM), intermittent intra-operative nerve monitoring (I-IONM) and continuous intra-operative nerve monitoring (C-IONM). There is ambiguity as to which of these strategies should be the preferred method of RLN preservation.

METHODS

A systematic review of the PubMed, Embase and the Cochrane Collaboration databases was undertaken with network meta-analysis (NMA) performed according to the PRISMA and Cochrane Collaboration guidelines. A Bayesian NMA was conducted using R packages netmeta with outcomes expressed as odds ratios (ORs) with 95% credible intervals (CrI). Only prospective studies were included.

RESULTS

Eighteen studies met inclusion criteria, including 22,080 patients and 40,642 nerves at risk (NAR). Overall, 23,364 NARs (57.5%) underwent I-IONM, 17,176 (42.3%) No-NM and 98 (0.2%) underwent C-IONM. There were no significant differences between groups regarding the incidence of permanent RLN injury following thyroid surgery (I-IONM vs.No-NM, OR 0.84, 95% CrI 0.55-1.19; C-IONM vs. No-NM, OR 0.44, 95% CrI 0.02-5.00). Pooled analysis showed that IONM (I-IONM or C-IONM) demonstrated a protective effect versus No-NM in reducing the incidence of transient RLN injury (OR 0.75, 95% CI 0.59-0.97, p = 0.03).

CONCLUSIONS

IONM strategies did not significantly reduce the incidence of permanent RLN injury following thyroid surgery. However, the small number of C-IONM NARs limits conclusions that may be drawn. Further well-designed prospective studies will be required to definitively assess the utility of C-IONM.

Tension-free thyroidectomy (TFT): initial report

The safety of thyroid surgery in terms of recurrent laryngeal nerve palsy and hypoparathyroidism has increased over the last decade. In this study, we present a new method of tension-free thyroidectomy (TFT), which could be used to further decrease the complication rate after a thyroidectomy. The procedure is based on the medial approach to the recurrent laryngeal nerve and the parathyroid glands after the division of the isthmus and successive complete dissection of Berry's ligament. In total, 92 patients (127 nerves at risk) underwent "tension-free thyroidectomy" (TFT) between August and November 2021. All the procedures were performed by a single surgeon at Saint Petersburg State University Hospital. There were 74 females and 18 male patients (ratio 4.1:1) with a mean age of 46.9 (range from 17 to 74). A lobectomy was carried out in 57 (62%) patients and a total thyroidectomy in 35 (38%). In 27 cases, patients additionally underwent central and/or lateral neck dissection. Indications for surgery were papillary carcinoma (N = 34), medullary cancer (N = 2), follicular neoplasia (N = 43), Grave's disease (N = 9), multinodular toxic goiter (N = 3), and multinodular nontoxic goiter (N = 1). Mean thyroid volume was 24.6 ml (ranged 12-70 ml). Intraoperative neuromonitoring was used in all the cases (5 mA). Translaryngeal ultrasound (TLUS) or direct laryngoscopy were routinely used prior and after surgery to evaluate vocal cords mobility. Calcium and parathormone levels were measured in patients after thyroidectomy on the first, 14th and 30th postoperative days. No recurrent laryngeal nerve palsy was observed. One patient exhibited hypoparathyroidism which was resolved in 2 weeks using substitution therapy with calcium and alfacalcidol. The mean operating time for lobectomy was 54 ± 14 min (range: 30-95 min) and for total thyroidectomy 99 ± 28 min (range: 55-158 min). There was no conversion to the conventional lateral-to-medial approach. TFT can be considered a safe and feasible operation. Comparative (randomized studies) with conventional dissection technique should be performed to investigate the hypothesis that this approach can provide a lower complication rate.

Ultrasound of the vocal cords in infants

Vocal cord paralysis is a common cause of respiratory and feeding problems in the pediatric population. While the causes of vocal cord paralysis are multiple, iatrogenic injury of the recurrent laryngeal nerve after cardiovascular surgery is the most frequent cause. Vocal cord paralysis increases the risk of swallowing dysfunction, tracheal aspiration and pneumonia. It also increases the need for nasoenteric feeds and gastrostomy tube placement. Flexible nasopharyngolaryngoscopy is considered the gold standard for diagnosing vocal cord paralysis, but it has significant drawbacks: it is uncomfortable, it can trigger a cardiovascular event in children with unstable cardiovascular status, it can be challenging to perform, and it can be difficult to interpret. Laryngeal US has become a popular imaging modality to evaluate the function of the vocal cords. Laryngeal US is well-tolerated, easy to perform, simple to interpret and has a lower physiological impact compared to flexible nasopharyngolaryngoscopy. Laryngeal US is an accurate and low-cost diagnostic test for vocal cord paralysis. In this review, we describe the anatomy of the larynx and recurrent laryngeal nerve; the causes, symptoms and pathophysiology of vocal cord paralysis; laryngeal US technique; diagnostic criteria for vocal cord paralysis; and a reporting system.

A prospective observational study

BACKGROUND

The continuous intraoperative neuromonitoring (C-IONM) of the recurrent laryngeal nerve (RLN) could help reducing the incidence of nerve paralysis after thyroid surgery, in comparison with the mere anatomical visualization of the RLN. The objective is to assess the efficacy and utility of C-IONM as a predictive test for recurrent laryngeal nerve paralysis after thyroidectomy.

METHODS

A prospective observational study was performed in 248 patients who underwent thyroid surgery where C-IONM was applied, between September 2018 and December 2019, in a high-volume center. A previous and later laryngoscopy was performed, which allowed to evaluate the reliability of the C-IONM as a predictive test for recurrent paralysis. Sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) were studied.

RESULTS

A total number of 171 thyroidectomies, 62 hemithyroidectomies, 15 totalization thyroidectomies and 27 thyroidectomy with cervical dissections were performed. Postoperative laryngoscopy was altered in 40 patients (16.12%). The SE, SP, PPV and NPV values ​​were 65%, 94.7%, 70.2% and 93.4% respectively.

CONCLUSIONS

C-IONM is a safe technique that provides real-time information about anatomical and functional integrity of the RLN and can improve the results of thyroid surgery.

Temporal expression of Laminin-111 in the developing rat larynx

Laminin-111 is a basement membrane protein that participates in motor innervation and reinnervation. During axonal pathfinding, laminin-111 interacts with netrin-1 (NTN1) and changes its attractant growth cone properties into repulsion. While previous models of recurrent laryngeal nerve (RLN) transection show increased Laminin-111 and NTN1 production after injury, developmental expression in the larynx has not been defined. This study investigates the expression of laminin-111 in laryngeal muscles during primary laryngeal innervation of Sprague Dawley rats. Adult larynges and embryos were sectioned for immunohistochemistry with βIII-Tubulin, laminin subunit α-1 (LAMA1), NTN1, and α-bungarotoxin. Sections were processed for single-molecule inexpensive RNA fluorescence in situ hybridization analysis of LAMA1 mRNA. LAMA1 expression increased in all intrinsic laryngeal muscles, except the medial thyroarytenoid (MTA), at E20.5. At E20.5 there was increased expression in the lateral thyroarytenoid (LTA) and posterior cricoarytenoid (PCA) compared to the MTA. NTN1 upregulation was limited to the LTA and lateral cricoarytenoid (LCA) at E16.5 without any increase in the MTA or PCA. LAMA1 and NTN1 expression did not strictly follow expected patterns relative to the known timing of innervation and does not appear to be acting similarly to its role following RLN injury. These differences between developmental and post-injury innervation provide targets for investigations of therapeutics after nerve injury.

Evaluation of thyroid Zuckerkandl tubercle by computed tomography

PURPOSE

This study investigated the incidence of thyroid Zuckerkandl Tubercle (ZT) using a computed tomography (CT) scan of the neck with contrast to identify the typologies in ZT-positive CT scans, investigate the presence of nodules located in that area, and compare the results with the relevant literature.

METHODS

We selected and retrospectively examined the CT scan images of patients who presented to our clinic with CT scans of the neck with contrast that clearly showed thyroid tissue and boundaries. Patients were evaluated based on age, gender, and presence of thyroid ZT. Patients with thyroid ZT were further investigated for localization and type of tubercles as well as for presence of nodules at the tubercle level.

RESULTS

A total of 1000 patients (mean age: 48.4 ± 19.1) were included in the study. Out of the total 222 (22.2%) patients who had thyroid ZT, 134 (60.4%) patients had unilateral thyroid ZT on the right side and 29 (13.1%) patients had unilateral thyroid ZT on the left side; 59 (26.6%) patients had bilateral thyroid ZT. In addition, nodules at the ZT level were observed in 13 (1.3%) of the patients. A review of all cases with ZTs indicated that 63% were Type 1, 31% were Type 2, and 5% were Type 3.

CONCLUSION

During the thyroid operations, ZT is essential for locating the recurrent laryngeal nerve. Reporting the presence of ZTs based on CT scans is crucial because it can prevent unnecessary interventional procedures, misdiagnoses, and likely complications in patients with planned thyroid operations.

Real-time detection of the recurrent laryngeal nerve in thoracoscopic esophagectomy using artificial intelligence

BACKGROUND

Artificial intelligence (AI) has been largely investigated in the field of surgery, particularly in quality assurance. However, AI-guided navigation during surgery has not yet been put into practice because a sufficient level of performance has not been reached. We aimed to develop deep learning-based AI image processing software to identify the location of the recurrent laryngeal nerve during thoracoscopic esophagectomy and determine whether the incidence of recurrent laryngeal nerve paralysis is reduced using this software.

METHODS

More than 3000 images extracted from 20 thoracoscopic esophagectomy videos and 40 images extracted from 8 thoracoscopic esophagectomy videos were annotated for identification of the recurrent laryngeal nerve. The Dice coefficient was used to assess the detection performance of the model and that of surgeons (specialized esophageal surgeons and certified general gastrointestinal surgeons). The performance was compared using a test set.

RESULTS

The average Dice coefficient of the AI model was 0.58. This was not significantly different from the Dice coefficient of the group of specialized esophageal surgeons (P = 0.26); however, it was significantly higher than that of the group of certified general gastrointestinal surgeons (P = 0.019).

CONCLUSIONS

Our software's performance in identification of the recurrent laryngeal nerve was superior to that of general surgeons and almost reached that of specialized surgeons. Our software provides real-time identification and will be useful for thoracoscopic esophagectomy after further developments.