Nerve stimulation in thyroid surgery: is it really useful?

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.

Thyroidectomy With or Without Nerve Identification: A Personal Experience and Technique

INTRODUCTION

Careful and precise dissection of the gland, away from the typical trajectory of the recurrent and external laryngeal nerves, poses a minimal or similar risk of nerve injuries compared to directly visualizing and identifying the nerves.

MATERIALS AND METHODS

In a randomized controlled study involving 150 patients with various thyroid disorders who underwent different surgical procedures (total, near total, and hemi thyroidectomy), the patients were randomly assigned into two groups using a coin toss. The first group (G1) consisted of 75 patients who underwent thyroidectomy with nerve visual identification, while the second group (G2) comprised 75 patients without the requirement of nerve visualization. The aim was to determine the method with a lower risk of complications.

RESULTS

The incidence of external laryngeal nerve palsy (ELNP) was found to be higher in G1 patients compared to G2 patients (5.3% vs 2%), while no cases of permanent recurrent laryngeal nerve (RLN) palsy were observed in either group. The frequency of total nerve injury was higher in G1, with 14 patients (10.2%), compared to G2, with eight patients (5.3%). However, there was no significant association between nerve identification and the rate of nerve injury (P value = 0.452). Among the different surgical procedures, total thyroidectomy for toxic goiter was the most common operation associated with transient external laryngeal nerve (TELN) injury and permanent external laryngeal nerve (PELN) injury.

CONCLUSION

 By employing meticulous dissection techniques in proximity to the thyroid capsule, experienced surgeons can effectively reduce the risk of nerve injury, even in the absence of direct nerve visualization.

The role of intraoperative neuromonitoring in thyroid surgery training

Aim: Intraoperative nerve monitoring (IONM) during thyroid surgery has been widely accepted as an additive improvement to the gold standard of visually identifying the RLN. This study aims to evaluate the role of IONM application in thyroid surgery education during general surgery residency. Materials and Methods: Patients who underwent total thyroidectomy between January 2012 and December 2019 were included in the study. The patients were divided into 2 groups according to the use of IONM (Group 1: With IONM, Group 2: Without IONM). These groups were also divided into subgroups as assistants and experts among themselves. Results: This study involved 256 patients. There were 116 patients in group 1, and 140 patients in group 2. Histologic analysis results revealed that IONM was used more frequently in patients with a malignancy (p=0.015). The median operative time was significantly longer when IONM was used, with an operative time of 130 minutes for group 1 and 120 minutes for group 2 (p=0.015). When Group 1B and Group 2B were compared among themselves, the median operation time in Group 1B was 130 minutes, and the median operation time in Group 2B was 125 minutes (p=0.026). In the comparison between Groups 1B and 2B, it was detected that the rate of use of IONM was higher in malignancies (p=0.025). Conclusion: According to our results, the use of IONM did not reduce the incidence of RLN paralysis in thyroidectomy performed by specialists and residents.

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.

The effect of intraoperative neuromonitoring on the number of lymph nodes excised and recurrence when applied during neck dissection in cases of papillary thyroid cancer

Purpose

The aim of this study was to evaluate the effect of neuromonitoring on the number of lymph nodes (LNs) removed when applied during neck dissection.

Methods

A total of 166 patients receiving neck dissection due to papillary thyroid cancer were separated into 2 groups (monitoring group, n = 76; non-monitoring group, n = 90).

Results

The number of LNs dissected was observed to be statistically significantly higher in the monitoring group (P = 0.001), and the difference between the groups in the number of positive LNs was significant (P = 0.031). There was seen to be a negative relationship between the number of positive LNs dissected and recurrence (r = –0.404, P = 0.005).

Conclusion

Intraoperative neuromonitoring during neck dissection makes a positive contribution to the prevention of the development of recurrence by increasing the number of LNs excised and the number of metastatic LNs.

Improving classification of the external branch of the superior laryngeal nerve with neural monitoring: a research appraisal and narrative review

Objective

To review the published literature on external branch of superior laryngeal nerve (EBSLN) neural monitoring and propose a new EBSLN classification system using intraoperative neural monitoring (IONM).

Background

The injury rate of the external branch of the superior laryngeal nerve (EBSLN) in thyroid surgery is 0-58%. Symptoms of EBSLN injury are not consistent, and patients often complain of modification of the voice timbre with the preservation of vocal cord function. Standards for the diagnosis of EBSLN injury are lacking.

Methods

The PubMed database was searched using the terms 'External branch of the superior laryngeal nerve' and 'Intraoperative neuromonitoring' from 2010 through March 2020.

Conclusions

This paper reviewed the anatomy of the EBSLN, the diagnosis and treatment of injury, and the application of IONM in the EBSLN. The traditional EBSLN classification method was analyzed and compared with our new classification method. The diagnosis of EBSLN injury is a problem that still needs to be resolved. For anatomic classifications of the EBSLN, we found that the conventional classification systems may not accurately reflect the real status of the EBSLN and the surgical risks that may occur intraoperatively. Using IONM, we developed an EBSLN classification method that was consistent with conventional diagnosis and treatments and can be widely and easily utilized during surgery.

Introducing routine intraoperative nerve monitoring in a high-volume endocrine surgery centre: a health technology assessment

We sought to analyse the effect of the introduction of intraoperative nerve monitoring (IONM) in our routine surgical practice and to provide a circumstantial analysis of direct costs of IONM in total thyroidectomy and of indirect costs associated with vocal fold palsy, as centred in the health care system of Italy. We retrospectively compared outcomes of 232 total thyroidectomies performed between November 2017 and October 2019, respectively, before (109 TT-Group A) and after (123 TT-Group B) adopting IONM technology in November 2018. We analysed the costs of IONM per procedure and rate and costs of vocal fold palsy events (temporary and permanent). Overall, there were 61 thyroid cancers (32 in Group B) and 171 multinodular goitres (91 in Group B). We recorded 5 cases of vocal fold palsy (4.6%-4 transient, 1 permanent) in Group A and none in Group B (p = 0.016). IONM consumables cost 219 eur per case. Healthcare and social cost of Vocal fold palsy ranged between 3200 eur (function recovery < 1 month postoperatively) and over 32,000 eur (permanent event). When only direct costs are considered, IONM can hardly be cost effective. In this study, cost of IONM implementation was offset by the absence of complications attributable to recurrent laryngeal nerve dysfunction.

Intraoperative nerve monitoring in thyroid surgery: Analysis of recurrent laryngeal nerve identification and operative time

OBJECTIVE

To evaluate the clinical value of intraoperative nerve monitoring (IONM) by comparing the procedure times for thyroidectomies performed with and without IONM.

METHODS

A prospective, randomized, controlled study was conducted on 32 patients (representing 41 nerves at risk) undergoing thyroidectomies carried out by two experienced head and neck surgeons (CC & WP). Sixteen thyroidectomies were performed without IONM (the "non-IONM group"), while 16 thyroidectomies were performed with IONM (the "IONM group"). The measured datapoints were setup time, time to visual identification of the recurrent laryngeal nerve (RLN), time to confirm the RLN electrophysiologically, dissection time, and total operative time.

RESULTS

With both surgeons, the IONM group had shorter visual times to RLN identification than the non-IONM group (CC: 3.7 minutes vs 5.3 minutes; WP: 3.4 minutes vs 9.7 minutes). Additionally, the electrophysiological identification time for the IONM group was shorter than the visual identification time for the non-IONM group. The setup times, dissection times, and total operative times of the 2 groups did not significantly differ (P > .05). No RLN injuries were observed.

CONCLUSIONS

IONM reduces the time needed for RLN identification in thyroidectomies. Functional RLN confirmation can reassure surgeons of the operative results. Moreover, use of IONM does not significantly impact setup and total operative times.

LEVEL OF EVIDENCE

2.

Lidocaine Infusion Improves the Functionality of Intraoperative Nerve Monitoring During Thyroid Surgery: A Prospective, Randomized, Double-Blinded Study

BACKGROUND

Intraoperative nerve monitoring (IONM) to assess the recurrent laryngeal nerve function during thyroid surgery is becoming the standard of care across many institutions. The successful deployment and data analysis from the IONM require complete laryngeal relaxation and reflex suppression. We investigated the role of intravenous lidocaine infusion (IVLI) to provide such operating conditions, under a lighter plane of anesthesia and fewer hemodynamic fluctuations.

METHODS

Sixty-five patients were randomly assigned to lidocaine group (LG) or placebo group (PG) based on the computer-generated coding developed by the pharmacy department. The study medication (SM) was delivered by the pharmacist in a pre-filled coded syringe to the investigator 30 min prior to the surgery. All the patients were anesthetized by narcotic and inhalation based general anesthesia. The SM was administered at the rate of 1.5mg/kg/h following a loading dose of 1 mg/kg. Dragonfly® laryngeal surface electrode and Nerveana® nerve locator system were used for IONM during surgery.

RESULTS

The proportion of patients requiring lower strength stimulating current (StMC) at 0.5 mA was significantly higher in the LG than in the PG (X2 (1, N = 61) = 10.1615, P = 0.001434). Similarly, the proportion of patients with the drop in the aggregate impedance level (DAIL) by < 50% at the end of surgery was significantly higher in the LG than in the PG (X2 (1, N = 61) = 15.982, P = 0.000064). In addition, the proportion of patients with the hypotensive episodes requiring rescue medications more than twice during surgery was significantly lower in the LG than in the PG (X2 (1, N = 61) = 0.0183, P < 0.05).

CONCLUSIONS

The enhanced laryngeal relaxation and the reflex suppression afforded by the IVLI could have enabled a lower StMC to elicit a positive signal. The lower StMC promotes less intense laryngeal alterations as evidenced by the lower DAIL in the LG. IVLI can enhance the functionality of the IONM during prolonged operating time and the resultant increased number of IONM stimulations, while providing a stable hemodynamic environment.

Should intraoperative nerve monitoring be used routinely in primary thyroid surgeries?

Objective:

This study presents the effects of intraoperative nerve monitoring on RLN injuries in patients who underwent primary surgery for benign thyroid pathology.

Methods:

We retrospectively evaluated the data of 273 patients who had primary thyroidectomy due to benign thyroid pathology between January 2012 and July 2017. The patients were classified into two groups. Group-1 consists of patients whose nerves were monitored. We separated the patients whose nerves were not monitored into Group-2.

Results:

There were 140 and 133 patients in Groups 1 and 2, respectively. Regarding the age, gender and surgical indication between the groups, statistically significant difference was not found (P > 0.05). In Group-1, transient paralysis developed in four patients (2.9%). The permanent paralysis developed in one patient (0.7%). In Group-2, transient paralysis developed in nine patients (6.8%). The permanent paralysis developed in four patients (3%). When the groups were evaluated, there was statistically significant difference in terms of transient and permanent paralysis (P=0.01, P =0.001, respectively).

Conclusions:

In view of the negative effects of RLN injury on the patient, we think that intraoperative nerve monitoring should be used routinely in benign thyroid surgeries.

Routine Intraoperative Neuromonitoring of the Recurrent Laryngeal Nerve to Facilitate Complete Resection and Ensure Safety in Thyroid Cancer Surgery

Routine use of intraoperative neuromonitoring (IONM) in thyroid cancer surgery is controversial. We aimed to investigate whether it improves the completeness of thyroidectomy and ensures safety. This retrospective study included 380 thyroid cancer patients who underwent thyroidectomy, by one surgeon, between July 2006 and November 2015. Patients were grouped according to the surgeon's adaptation of IONM, as follows: none (period 1; n = 92), early (period 2; n = 141), and late (period 3; n = 147). The operative time and rates of vocal cord palsy were determined. Surgical completeness was assessed by technetium-99m imaging of the thyroid remnant and serum thyroglobulin measurement before ablation. The rate of recurrent laryngeal nerve (RLN) palsy showed a decreasing trend over time. No permanent RLN palsies occurred in nerves not invaded by tumor after routine IONM was introduced. Technetium-99m uptake (periods 1–3, 0.62 vs 0.32 vs 0.20; P < 0.01) and thyroglobulin levels (periods 1 and 2, 37.93 vs 8.98 ng/mL, respectively; P = 0.034; period 3, 9.10 ng/mL) progressively decreased. The mean thyroglobulin level dropped significantly after introduction of routine IONM. We conclude that routine IONM during thyroid cancer surgery improves surgical completeness and might prevent permanent RLN palsy over time.

Is intraoperative nerve monitoring useful for surgical training in thyroid surgery?

Objectives

Parathyroid glands and recurrent laryngeal nerves (RLNs) are at risk during thyroid surgery. However, the identification of the nerves has reduced these risks. Intraoperative nerve monitoring (IONM) during thyroid surgery has gained widespread acceptance as an aid to the gold standard of visually identifying the RLN. The aim of the present study was to evaluate the effect of the identification of the RLN during thyroidectomy by using IONM.

Material and Methods

Seven hundred forty-eight patients were included in our prospectively designed study. Of these 748 patients, 1496 nerves at risk were studied. Group 1 consisted of 736 nerves that were identified using IONM, whereas Group 2 consisted of 760 visually identified nerves.

Results

In the non-IONM group, the rate of temporary nerve palsy was lower in patients operated by experienced surgeons than in patients operated by residents (p= 0.001). In the IONM group, RLN injury rates were similar between experienced surgeons and residents.

Conclusion

In spite of the fact that the duration of the operation was lower with IONM, the abbreviated duration may not appear to have clinical significance. The main advantage is for less experienced surgeons. IONM significantly decreases RLN palsy rates of the surgeons with limited experience in thyroid surgery.

Surgical anatomy of the external branch of the superior laryngeal nerve: a systematic review and meta-analysis

PURPOSE

To provide a comprehensive evidence-based assessment of the anatomical characteristics of the external branch of the superior laryngeal nerve (EBSLN).

MATERIALS AND METHODS

A thorough systematic search was performed on the major electronic databases PubMed, EMBASE, Cochrane library, and ScienceDirect to identify eligible studies. Data were extracted and pooled into a meta-analysis. The primary outcomes were the EBSLN identification rate (total number of EBSLN identified divided by the total number of dissected hemilarynges) and the prevalence of various EBSLN types.

RESULTS

A total of 56 studies (n = 13,444 hemilarynges) were included. The overall pooled EBSLN identification rate was 89.24% (95% CI 85.49-92.49). This rate was higher for cadaveric (95.00%; 95% CI 89.73-99.35) compared to that reported in intraoperative studies (86.99%; 95% CI 82.37-91.01). Significantly higher identification rates were reported for studies in which intraoperative nerve monitoring was used (95.90%; 95% CI 94.30-97.25) compared to those which only relied on direct visual identification of the EBSLN (76.56%; 95% CI 69.34-83.08). Overall, Cernea type IIa (nerves crossing the superior thyroid artery less than 1 cm above the upper edge of the superior thyroid pole) and Friedman type 1 (nerves running their entire course superficial to the inferior pharyngeal constrictor) were the most prevalent (41.84%; 95% CI 33.28-48.08 and 50%; 95% CI 29.90-65.62, respectively). The combined prevalence of Cernea IIa and IIb (nerves crossing the superior thyroid artery below the upper edge of the superior thyroid pole) was higher in intraoperative studies compared to that in cadaveric studies (64.3% vs 49.4%). The EBSLN coursed medial to the superior thyroid artery in 70.98% (95% CI 55.14-84.68) of all cases.

CONCLUSION

The use of intraoperative nerve monitoring improves EBSLN identification rates. In light of the highly variable anatomical patterns displayed by the EBSLN, thorough pre-operative knowledge of its anatomy can be crucial in minimizing incidences of its iatrogenic injury.

Medico legal aspects on neuromonitoring in thyroid surgery: informed consent on malpractice claims

AIM

The purpose of this paper is to provide a forensic profile framework of neuromonitoring in thyroid surgery, regarding the information given to the patient and its classification as part of professional liability in the event of recurrent injury.

METHOD

Evaluation and reflections on the required behaviour of the surgeon on providing details on the operation before the informed consent is given and to outline the possible legal implications regarding professional liability as a result of recurrent injury. In particular, if it is an obligation to inform the patient about using this method and if it is possible for the surgeon to freely choose whether to employ this method, which is still burdened by a certain percentage of error and for that reason it cannot be defined a "standard of care".

RESULTS

To recognize neuromonitoring the role of standard of care in surgery of the thyroid means attribute a role of method able to avoid the surgeon to cause iatrogenic damage to the laryngeal nerve. For the foregoing reasons that is not true, determining false positives and false negatives, and this can be a double edged sword for the surgeon.

CONCLUSIONS

Although the progress in the field of thyroid surgery made in the last decade, currently there is no scientific reassuring evidence to completely avoid the possibility of producing an iatrogenic lesion of the laryngeal nerve. Information given to the patient prior to surgery should respect the requirements of completeness, freedom and honesty in order to allow the patient to self-determination.

Analyzing cost-effectiveness of neural-monitoring in recurrent laryngeal nerve recovery course in thyroid surgery

PURPOSE

The increasing use of intraoperative neural monitoring (IONM) of the recurrent laryngeal nerve (RLN) during thyroid surgery imposes an evaluation of cost-effectiveness.

METHODS

The analysis estimated the cost versus utility of different alternatives that simulate nerve injury course and the consequences for the following cohorts of patients: (1) no RLN injury, or vocal fold palsy (VCP) recovery within 1 month (2), 2 months (3), 6 months (4), and after 12 months (5). In the model applied, the average simulated cohort consisted of a young female patient, 40 years old, employed, daily voice user, who underwent elective, conventional total thyroidectomy via cervical incision using a standardized intermittent IONM technique, for an operable benign, bilateral, diffuse, multinodular, non-toxic, non-retrosternal goiter.

RESULTS

IONM was cost-ineffective when parameters such as the rates of transient vocal fold palsy (VCP) reached 38.5%. IONM was cost-effective if the rate of VCP was 33.6% at 1 month, 22.9% at 2 months, 9.8% at 6 months, and 3.8% at 12 months, independent of phono-surgery. The described scenario is cost-effective only in a high-volume setting.

CONCLUSIONS

This study used simulation economic modeling to assess clinical and cost-effectiveness utility of IONM implementation. In light of the limitations of a simulation-based study, we conclusively assumed that IONM is cost-effective for permeant RLN injuries.

Opportunities and challenges of intermittent and continuous intraoperative neural monitoring in thyroid surgery

The number of thyroid operations and there radically continues to rise in the western hemisphere, bringing prevention of recurrent laryngeal nerve (RLN) palsy to the fore. Overall, the incidence of RLN palsy is fairly low but continues to prompt litigation for malpractice. In an effort to diminish transient, and more importantly permanent, RLN palsy rates, intraoperative neuromonitoring (IONM) has been advocated as a risk minimization tool. Recent meta-analyses of studies, many of which were limited by poor study design and the sole use of intermittent nerve stimulation, were unable to demonstrate superiority of IONM over mere anatomic RLN dissection. This is where continuous IONM (CIONM) comes into play: this technology enables the surgeon to (I) identify impending nerve injury as it unfolds; (II) release distressed nerves by reversing causative surgical maneuvers; and (III) verify functional nerve recovery after intraoperative loss of the electromyographic signal. Despite this superiority, CIONM is not devoid of methodological limitations, which need to be accounted for. This review summarizes the current key achievements of IONM; outlines opportunities for improvement regarding clinical implementation; and suggests areas of future research in this rapidly evolving field.

Injury of the external branch of the superior laryngeal nerve in thyroid surgery

The external branch of the superior laryngeal nerve (EBSLN) innervates the cricothyroid muscle (CTM) to promote lengthening and thinning of the vocal fold, thus increasing voice pitch. The close relation with the superior thyroid vessels (STV) puts the EBSLN in risk every time the superior pole of the thyroid is dissected. It travels downward to innervate the CTM, lateral to the thyroid cartilage and to the inferior pharyngeal constrictor muscle (IPCM), being eventually covered by this muscle fibers as it approaches its entry point. During its descending course, the EBSLN curves and crosses the STV posteriorly. The lower this crossing occurs in the neck, the higher the risk of surgical damage to the nerve by transection, traction, entrapment, thermal damage or disrupted blood supply. The chances of surgical trauma are also increased by size and weight of the specimen, shorter neck length and non-white ethnicity. Voice changes following thyroid surgery are common and multifactorial. The actual rate of vocal impairment due to EBSLN injury is unclear, since changes to the everyday speaking voice can be minimal and laryngeal findings are usually subtle and controversial. CTM electroneuromyography (EMG) is the most accurate tool to diagnose abnormal EBSLN conductivity, but it is technically difficult and barely applicable in routine practice. Recommended approaches to prevent injury include: (I) individual distal ligature of the STV by the thyroid capsule; (II) visual identification of the nerve and its trajectory and (III) electrostimulation with either observation of CTM twitch or intraoperative nerve monitoring (IONM) via dedicated endotracheal tube electrodes. There is accumulating evidence that a combination of visual and standardized electrophysiological EBSLN identification with meticulous division of the STV improves preservation rates. IONM bears the additional benefits of prognostication, quantification and documentation of neural function once it allows intraoperative laryngeal EMG.

[Intraoperative neuromonitoring in thyroid surgery]

BACKGROUND

Intraoperative neuromonitoring of the recurrent laryngeal nerve in thyroid surgery facilitates the identification of anatomical structures in cervical endocrine surgery reducing the frequency of vocal cord paralysis.

OBJECTIVE

To study the normal electrophysiological values of the vague and recurrent laryngeal nerves before and after thyroid surgery. To compare rates of injury of recurrent nerve before and after the introduction of the intraoperative neuromonitoring in thyroid surgery.

MATERIAL AND METHODS

An observational, descriptive and prospective study in which a total of 490 patients were included. Between 2003-2010, surgery was performed on 411 patients (703 nerves at risk) with systematic identification of recurrent laryngeal nerves. Between 2010-2011 neuromonitorization was also systematically performed on 79 patients.

RESULTS

Before the introduction of intraoperative neuromonitoring of 704 nerves at risk, there were 14 recurrent laryngeal nerve injuries. Since 2010, after the introduction of the intraoperative neuromonitoring in thyroid surgery, there has been no nerve injury in 135 nerves at risk.

CONCLUSIONS

We consider the systematic identification of the recurrent laryngeal nerve is the 'gold standard' in thyroid surgery and the intraoperative neuromonitoring of nerves can never replace surgery but can complement it.

Safety and Effectiveness of Total Thyroidectomy and Its Comparison with Subtotal Thyroidectomy and Other Thyroid Surgeries: A Systematic Review

Diseases associated with the thyroid gland are one of the most frequently seen endocrine disorders across the globe. Total thyroidectomy is currently the preferred treatment for many thyroid diseases. Controversies exist among surgeons regarding safety of total thyroidectomy due to the risk associated with it like postoperative hypoparathyroidism or recurrent laryngeal nerve damage. Since, in the recent years, the incidence of thyroidectomy is in increasing trend in south Indian population, this review aims to study the available data regarding the appropriateness and safety of total thyroidectomy and compares it with subtotal thyroidectomy and other thyroid surgeries. This is a retrospective comprehensive review of various articles and publications regarding total and partial thyroidectomy performed across the world. Many retrospective studies and few prospective studies suggest that the incidence of transient hypocalcemia is higher after total thyroidectomy than after subtotal thyroidectomy, but the incidence of other complications including recurrent laryngeal nerve palsy and postoperative hematoma is not significantly different between the two procedures. Hence in our review we found that total thyroidectomy is safe and cost effective with low complication rates and provides little significant advantage of being safer procedure compared to subtotal thyroidectomy.

Is Nerve Monitoring Required in Total Thyroidectomy? Cerrahpasa Experience

Thyroidectomy is an elective operation performed in an anatomically complex region in which certain structures are responsible for vital functions and special senses. This study aims to compare the effects of two different technical approaches-nerve dissection combined with intraoperative nerve monitoring (IONM) and no nerve identification-on recurrent laryngeal nerve (RLN) damage in total thyroidectomy. One hundred and sixty-one consecutive cases that underwent total thyroidectomy and 322 RLN under risk were evaluated. In group 1 (n = 162), nerve dissection combined with IONM was performed, whereas no RLN identification was performed in group 2 (n = 160). While the duration of operation in group 1 (34.23 ± 12.21 min) was statistically shorter than that in group 2 (36.98 ± 16.79 min, p = 0.017), there was no significant difference between groups related to RLN palsy (group 1 n = 10, group 2 n = 7). Use of IONM was found only to shorten the duration of operation. According to our presented experience, there is no benefit of IONM-combined routine dissection of RLN during total thyroidectomy on the prevention of RLN palsy.

Laryngeal nerve monitoring

Intraoperative neurophysiological monitoring of the vagus and recurrent laryngeal nerves is increasingly used during thyroidectomy, parathyroidectomy, skull base surgery, and cervical discectomy with fusion. Monitoring can assist in nerve localization and in reducing the incidence of neural trauma. To be effective, however, monitoring must be correctly implemented and the results interpreted based on an in-depth understanding of technique and the surgical structures at risk. Because "poor monitoring is worse than no monitoring" all members of the surgical monitoring team must have training specific to laryngeal recording to maximize its benefit and minimize pitfalls. This publication will review pertinent anatomy and neurophysiology as well as technical and interpretative factors.

Use of the Nerve Integrity Monitor during Thyroid Surgery Aids Identification of the External Branch of the Superior Laryngeal Nerve

BACKGROUND

The external branch of the superior laryngeal nerve (EBSLN) is at risk during thyroid surgery. Despite meticulous dissection and visualization, the EBSLN can be mistaken for other structures. The nerve integrity monitor (NIM) allows EBSLN confirmation with cricothyroid twitch on stimulation.

AIMS

The aim of this study was to assess any difference in identification of EBSLN and its anatomical sub-types by dissection alone compared to NIM-aided dissection.

METHODS

Routine intra-operative nerve monitoring (IONM) was used, when available, for 228 consecutive thyroid operations (129 total thyroidectomies, 99 hemi-thyroidectomies) over a 10-month period. EBSLN identification by dissection alone (with NIM confirmation of cricothyroid twitch) and by NIM-assisted dissection was recorded prospectively. Anatomical sub-types were defined by the Cernea classification.

RESULTS

Of 357 nerves at risk, 97.2 % EBSLNs (95 % confidence interval [CI], 95.5-98.9) were identified by visualization and NIM-aided dissection compared to 85.7 % (95 % CI, 82.1-89.3) identified by dissection alone (<0.001). EBSLN frequency was 34 % for type 1, 55 % for type 2a, and 11 % for type 2b. All identified EBSLNs were stimulated to confirm a cricothyroid twitch after superior thyroid vessel ligation.

CONCLUSION

Using the NIM and meticulous dissection of the upper thyroid pole improves EBSLN identification. As the EBSLN is at risk during thyroidectomy and can lead to voice morbidity, the NIM can aid identification of the EBSLN and provide a functional assessment of the EBSLN after thyroid resection.

Differentiated thyroid cancer-personalized therapies to prevent overtreatment

The concept of individualized therapy is rapidly gaining recognition in the management of patients with differentiated thyroid cancer (DTC). This Review provides an overview of the most important elements of this paradigm shift in DTC management and discusses the implications for clinical practice. In the majority of patients with DTC who have an inherently good prognosis, the extent of surgery, the dosage of (131)I therapy and the use of levothyroxine therapy are all aspects suitable for individualization, on the basis of both the stage of disease and the response to treatment. In individuals with advanced disease, newer imaging techniques, advances in (131)I therapy and the use of targeted molecular therapies (such as multitargeted kinase inhibitors) have provided new options for the personalized care of patients, for whom until recently no effective therapies were available. Individualized therapies could reduce adverse effects, including the sometimes debilitating hypothyroidism that used to be required before initiation of (131)I treatment, and major salivary gland damage, a common and unpleasant side effect of (131)I therapy. Highly individualized interdisciplinary treatment of patients with DTC might lead to improved outcomes with reduced severity and frequency of complications and adverse effects. However, in spite of ongoing research, personalized therapies remain in their infancy.

Identification alone versus intraoperative neuromonitoring of the recurrent laryngeal nerve during thyroid surgery: experience of 2034 consecutive patients

BACKGROUND

The aim of this study was to evaluate the ability of intraoperative neuromonitoring in reducing the postoperative recurrent laryngeal nerve palsy rate by a comparison between patients submitted to thyroidectomy with intraoperative neuromonitoring and with routine identification alone.

METHODS

Between June 2007 and December 2012, 2034 consecutive patients underwent thyroidectomy by a single surgical team. We compared patients who have had neuromonitoring and patients who have undergone surgery with nerve visualization alone. Patients in which neuromonitoring was not utilized (Group A) were 993, patients in which was utilized (group B) were 1041.

RESULTS

In group A 28 recurrent laryngeal nerve injuries were observed (2.82%), 21 (2.11%) transient and 7 (0.7%) permanent. In group B 23 recurrent laryngeal nerve injuries were observed (2.21%), in 17 cases (1.63%) transient and in 6 (0.58%) permanent. Differences were not statistically significative.

CONCLUSIONS

Visual nerve identification remains the gold standard of recurrent laryngeal nerve management in thyroid surgery. Neuromonitoring helps to identify the nerve, in particular in difficult cases, but it did not decrease nerve injuries compared with visualization alone. Future studies are warranted to evaluate the benefit of intraoperative neuromonitoring in thyroidectomy, especially in conditions in which the recurrent nerve is at high risk of injury.

Neuromonitoring of the laryngeal nerves in thyroid surgery: a critical appraisal of the literature

One of the most significant complication of thyroid surgery is injury of the recurrent laryngeal nerve. Injury of the external branch of the superior laryngeal nerve is a less obvious but occasionally significant problem. Recently, neuromonitoring during thyroidectomy has received considerable attention because of literature encouraging its use, but there is no consensus about its advantages and utility. A critical assessment of the literature on neuromonitoring was conducted in order to define its effectiveness, safety, cost-effectiveness and medical-legal impact. Available data does not show results superior to those obtained by traditional anatomical methods of nerve identification during thyroid surgery. Data about cost-effectiveness is scarce. The literature shows inconsistencies in methodology, patient selection and randomization in various published studies which may confound the conclusions of individual investigations. The current recommendation for use in "high risk" patients should be assessed because definition heterogeneity makes identification of these patients difficult. As routine use of neuromonitoring varies according to geography, its use should not be considered to be the standard of care.

Value of recurrent laryngeal nerve monitoring in the operative strategy during total thyroidectomy and parathyroidectomy

OBJECTIVE

The purpose of this study was to assess the role of recurrent laryngeal nerve (RLN) monitoring in the operative strategy during total thyroidectomy and parathyroidectomy. Due to the risk of serious respiratory complications of bilateral recurrent nerve paralysis, two-stage surgery may be considered in the case on negative stimulation of the first side.

PATIENTS AND METHODS

This prospective study was conducted in 100 consecutive patients between May 2007 and March 2011. Translaryngeal monitoring was performed. When stimulation of the RLN on the first side dissected was negative, dissection of the other side was deferred to avoid the risk of bilateral RLN paralysis.

RESULTS

The main surgical indications were thyroid carcinoma (34%), Graves' disease (27%), multinodular goitre (27%) and parathyroid hyperplasia (9%) with seven cases of redo surgery. Four RLN identified on the first side gave a negative response to stimulation and surgery to the other side was therefore deferred. Transient unilateral RLN paralysis was observed in these four patients and two cases of RLN paralysis were observed among patients with positive RLN stimulation. Among the 96 contralateral RLNs tested, two were not visualized (one case of transient RLN paralysis, one case of permanent RLN paralysis), two gave a negative response to stimulation (two cases of permanent RLN paralysis) and 92 gave a positive response to stimulation (nine cases of transient RLN paralysis, including two cases associated with transient paralysis of the first side, and one case of permanent RLN paralysis). The incidence of RLN paralysis by nerve was 9.6% for transient RLN paralysis and 2% for permanent (unilateral) RLN paralysis.

CONCLUSION

When bilateral RLN dissection is planned, RLN monitoring is particularly useful to limit the risk of bilateral RLN paralysis. Two-stage thyroidectomy, following functional recovery of the damaged RLN, can therefore be proposed. The risk of bilateral RLN paralysis was avoided in four patients, while transient bilateral RLN paralysis was observed in two patients despite positive stimulation.

Endolaryngeal hookwire electrodes for intraoperative recurrent laryngeal nerve monitoring during pediatric thyroid surgery

OBJECTIVE

To describe the senior author's surgical technique and discuss his experience with endolaryngeal hookwire electrodes for intraoperative, recurrent laryngeal nerve monitoring during pediatric thyroid surgery.

STUDY DESIGN

Consecutive case series.

SETTING

Tertiary-care, academic, children's hospital.

SUBJECTS AND METHODS

A consecutive case series review of pediatric patients (age <16 years) who underwent thyroid surgery with intraoperative, endolaryngeal hookwire recurrent laryngeal nerve monitoring. Nerve injury was defined as vocal cord dysfunction present >12 months postoperatively.

RESULTS

Seventeen patients were identified. There were 5 males and 12 females, and the average age was 11.7 years (range, 4-15 years). Nineteen procedures were performed--4 hemithyroidectomies, 2 completion thyroidectomies, and 13 total thyroidectomies--with 32 nerves at risk. One patient had a recurrent laryngeal nerve injury with a nerve paresis that persisted longer than 12 months postoperatively, making our recurrent laryngeal nerve injury rate 3.1% (1/32). Fortunately, the nerve eventually recovered to normal function.

CONCLUSION

Thyroid nodules and surgery in children consist of higher rates of malignancy and potentially higher risks for recurrent laryngeal nerve complications. Our injury rate was 3.1%. Intraoperative recurrent laryngeal nerve monitoring with endolaryngeal hookwire electrodes in pediatric thyroid surgery may be helpful in nerve identification and is very sensitive. This technique can be used in situations in which endotracheal tubes with surface electrodes cannot be accommodated by the smaller size of the pediatric airway.

"Mystic" transient recurrent nerve palsy after thyroid surgery

BACKGROUND

The mechanism of transient recurrent laryngeal nerve (RLN) palsy remains unclear.

METHODS

Samples were harvested from the RLN adjacent thyroid capsule and perineural fascia during 223 lobectomies and 89 RLNs from cadavers were used for histologic and immunohistologic evaluation. Intraoperative chromoendoscopic features of the RLN were compared with postoperative ear, nose, and throat examinations.

RESULTS

Those nerves that macroscopically seem to be single-branched (35 of 89 = 39.3%), microscopically consist of multiple fascicles in most of the cases (23 of 35 = 65.7%), resembling a plexus more than a single cord. Chronic lymphocytic infiltration of the thyroid capsule adjacent to the RLN was present in 29% (65 of 223) of the cases. The perineural fascia showed lymphocytic (18 of 223 = 8.1%) or granulocytic (7 of 223 = 3.1%) infiltration.

CONCLUSIONS

The origin of transient RLN palsy is multifactorial: plexus shaped microscopic nerve structure with or without branches, frame-like adventitial tissue, variable epineurium, inflammatory changes that involve not only the thyroid capsule but the perineural fascia, resultant nerve edema, and diffuse microhemorrhages by injury of fragile capillaries.

Loss of the nerve monitoring signal during bilateral thyroid surgery

Background

This study aimed to assess current use of recurrent laryngeal nerve monitoring (RLNM) for bilateral thyroid surgery in Germany. It explored the willingness of surgeons to change strategy after loss of signal (LOS) on the first side of resection.

Methods

Surgical departments in Germany equipped with nerve monitors were asked to complete a structured questionnaire, specifying the number of thyroidectomies done in 2010, and the frequencies of RLNM, vagal stimulation, and electromyographic (EMG) recording before and after thyroidectomy. They were also asked about the surgical plan for bilateral goitre after LOS on the first side of resection.

Results

Based on manufacturers' sales data, 1119 (89·1 per cent) of 1256 surgical departments in Germany were equipped with nerve monitors in 2010. A total of 595 departments (53·2 per cent), accounting for approximately 75 per cent of all thyroidectomies in Germany during that year, returned a completed questionnaire. RLNM was used in 91·7–93·5 per cent of thyroidectomies, with the addition of routine vagal stimulation in 49·3 per cent before, and 73·8 per cent after resection. EMG responses to vagal stimulation were recorded in 54·8 per cent before, and 72·5 per cent after resection. Some 93·5 per cent of surgeons changed the resection plan for the other side in bilateral thyroid surgery after LOS had occurred on the first side.

Conclusion

RLNM is now the standard of care during thyroidectomy in Germany. After LOS on the first side of resection in bilateral goitre, more than 90 per cent of respondents declared their willingness to change the resection plan for the contralateral side to avoid the risk of bilateral recurrent laryngeal nerve palsy.

Recurrent laryngeal nerve injury in thyroid surgery

OBJECTIVES

Vocal cord paresis or paralysis due to iatrogenic injury of the recurrent laryngeal nerve (RLNI) is one of the main problems in thyroid surgery. Although many procedures have been introduced to prevent the nerve injury, still the incidence of recurrent laryngeal nerve palsy varies between 1.5-14%. The aim of the present study is to assess the risk factors of recurrent laryngeal nerve injury during thyroid surgery.

METHODS

Patients who had thyroid surgery between 1990 and 2005 and were admitted to the surgical department of King Fahd hospital of the University, Al-Khobar, Saudi Arabia were enrolled for this retrospective review, Factors predisposing to recurrent laryngeal nerve injury were evaluated such as pathology of the lesions and the type of operations and identification of recurrent laryngeal nerve intra-operatively. Preoperative and postoperative indirect laryngoscopic examinations were performed for all patients.

RESULTS

340 patients were included in this study. Transient unilateral vocal cord problems occurred in 11 (3.2%) cases, and in 1 (0.3%) case, it became permanent (post Rt. Hemithyroidectomy). Bilateral vocal cord problems occurred in 2 cases (0.58%), but none became permanent. There were significant increases in the incidence of recurrent laryngeal nerve injury in secondary operation (21.7% in secondary vs. 2.8% in primary, p=0.001), total/near total thyroidectomy (7.2% in total vs. 1.9% in subtotal, p=0.024), non-identification of RLN during surgery (7.6% in non-identification vs. 2.6% in identification, p=0.039) and in malignant disease (12.8% in malignant vs. 2.9% in benign, p=0.004). However, there was no significant difference in the incidence of recurrent laryngeal nerve injury with regards to gender (4.1% in male vs 3.8% in female, p=0.849).

CONCLUSION

The present study showed that thyroid carcinoma, re-operation for recurrent goiter, non-identification of RLN and total thyroidectomy were associated with a significantly increased risk of operative recurrent laryngeal nerve injury.

Implementation of systematic neuromonitoring training for thyroid surgery

Neural monitoring is increasingly applied to thyroid surgery and yet few surgeons have received formal training in intraoperative neuromonitoring (IONM). Standardized application of neural monitoring is an expected outcome of formal training programs in IONM. This study was designed to document a systematic training course that focuses on standardized state-of-art IONM knowledge. Seventeen 1-day courses were organized by the Department of Surgical Sciences, University of Insubria Medical School (Varese-Como, Italy), between 2009-2010. The course included didactic and practical training sessions. Some specific steps and checklist identified for courses included: knowledge of IONM technology and troubleshooting algorithms; IONM anesthetic perspectives, standards of IONM equipment set up and technique. A total of 75 trainees completed a questionnaire after completion of the respective courses. Questions probed demographic data, operative IONM experience and evaluation of course content. Data gathered showed that 97% of participants had no prior experience with the standardized approach of IONM technique (i.e. stimulation of the vagal nerve). The most useful parts of the course were judged to be (a) algorithms for perioperative IONM problem solving (30%), (b) live surgery with hands-on training (25%), (c) standardization of IONM technique (25%), and (d) IONM equipment set-up (20%). Poor reimbursement for hospital thyroid procedures is the main reason of limitation of IONM technology. The course offered participants novel knowledge and training and gave participants a systematic and standard approach to IONM technique.

Intraoperative Monitoring of the Recurrent Laryngeal Nerve during Thyroidectomy: A Standardized Approach (Part 1)

One of the most feared complications in thyroid surgery is injury to the superior laryngeal nerve or recurrent laryngeal nerve. Neural identification during surgery is insufficient to assess nerve injury. Intraoperative nerve monitoring of the vagal nerve and recurrent laryngeal nerve during thyroid surgery is a new adjunct designed to allow better identification of nerves at risk and therefore reduce complications related to their injury. This new working tool does not substitute adequate surgical technique but merely provides the surgeon with an adjunct to routine visual identification and functional assessment. The use of nerve monitoring requires standardization of the monitoring procedure. Pursuant to this, we will discuss in two related articles the current state of the art standardized technique of nerve monitoring in thyroid surgery. The aim of part 1 is to provide a concise overview of nerve monitoring in thyroid surgery and its effectiveness. This will include a brief review of the surgical anatomy of the recurrent laryngeal nerve and the key landmarks used to identify the nerve during surgery. Part 2 will describe how to perform the standardized nerve monitoring in a step by step fashion during thyroid surgery which will diminish variable results and misleading information associated with a nonstandardized nerve monitoring procedure.

Loupe Magnification Reduces Postoperative Hypocalcemia after Total Thyroidectomy

We aimed to evaluate the impact of loupe magnification (LM) on incidental parathyroid gland removal (from pathology reports), hypocalcemia, and recurrent laryngeal nerve (RLN) injury after total thyroidectomy and answer the question of whether this tool should be always recommended for patient's safety. Between January 2005 and December 2008, 126 patients underwent total thyroidectomy with routine use of 2.5 X galilean loupes; their charts were compared with data on 118 patients operated on between January 1997 and December 2000 without LM (two different equally skilled surgical teams operating in the two periods). LM decreased the rate of inadvertent parathyroid glands removal (3.8 vs 7.8% of total parathyroid glands; P = 0.01), as well as of biochemical (20.6 vs 33.9%; P = 0.028) and clinical (12.7 vs 33%; P = 0.0003) hypocalcemia after thyroidectomy. All cases (16 of 16) of symptomatic hypocalcaemia in the LM group proved to be associated with parathyroidectomy vs 76.9 per cent (30 of 39) without LM ( P = 0.046). A trend toward decreased RLN injury rate, although statistically insignificant, was reported, being unilateral transient, unilateral permanent, and bilateral transient palsy rates 6.8, 2.5, and 1.7 per cent, respectively, without LM vs 4.8, 2.4, and 0.8 per cent, respectively, with LM ( P = 0.69; P = 1, and P = 0.61, respectively). Our results do support the routine use of LM during total thyroidectomy.