Systematic review with meta-analysis of intraoperative neuromonitoring during thyroidectomy

Comprehensive Mapping and Dynamic Monitoring of the Temporal Branch of the Facial Nerve in Complex Cranial Reconstruction Surgery and Revision Cranioplasty

Facial nerve (FN) injury is a significant risk during complex cranial reconstruction surgeries, especially in revision cases where normal anatomy is distorted. The authors introduce a technique to mitigate FN injury, including preoperative FN mapping, intraoperative FN mapping, and continuous FN monitoring. Preoperative mapping uses a handheld ball-tip stimulator to elicit compound muscle action potentials (CMAP) in the frontalis muscle. Needle electrodes are placed above the orbital margin to record responses, starting at the stylomastoid foramen and extending until the entire temporal branch is mapped. Intraoperatively, continuous mapping is achieved using an electrified insulated suction device, allowing dynamic mapping during soft tissue dissection. Continuous monitoring involves placing stimulation electrodes near the stylomastoid foramen and recording CMAP responses from the frontalis and orbicularis oculi/orbicularis oris muscles. The authors tested this technique in 5 patients. The authors successfully mapped the temporal branch of the FN with isolated frontalis CMAP recordings in all patients. Intraoperative FN mapping and continuous monitoring were successfully performed in all cases. Two patients experienced complete cessation of FN CMAPs, which resumed upon loosening the tension on the myocutaneous flap held by fishhooks. One patient showed a 39% decrement in frontalis CMAP that did not recover. Despite these issues, all patients had intact FN function postoperatively and at follow-up. Our technique shows promise in mitigating FN injury during complex cranial reconstruction and cranioplasty revision surgery. Further research with a larger cohort is needed to confirm efficacy and statistical significance.

The impact of intraoperative neural monitoring during papillary thyroid cancer surgery on completeness of thyroidectomy and thyroglobulin response: a propensity-score matched study

BACKGROUND

Intraoperative neural monitoring (IONM) has been utilized for a variety of thyroid pathologies, including papillary thyroid carcinoma (PTC). Remnant thyroid tissue following total thyroidectomy (TT) in patients with PTC is associated with increased recurrence. The aim of this study is to investigate whether the use of IONM in PTC surgery has an impact on the completeness of thyroidectomy.

METHODS

Retrospectively, patients with preoperative diagnosis of PTC, who underwent TT in a tertiary center were reviewed. They were grouped based on the IONM usage, and 1:1 propensity-score match was performed. Primary outcome was the completeness of thyroidectomy, determined by measuring postoperative stimulated thyroglobulin levels (sTg).

RESULTS

Among 274 clinically node-negative PTC patients who underwent TT and ipsilateral prophylactic central lymph-node dissection, a total of 170 patients (85:85) were matched. Postoperative sTg levels were significantly lower in the IONM group (1 ng/dL vs. 0.4 ng/dL; p < 0.01) with higher percentage of the patients with sTg levels <1 ng/ml (50.6% vs. 69.4%; p = 0.01). More patients in the no-IONM group received RAI ablation with significantly higher doses (mean mci: 120 vs. 102; p = 0.02).

CONCLUSION

The use of IONM during thyroidectomy provides improvement in the completeness of thyroidectomy and reduction in postoperative sTg levels which can be used as a guide by clinicians to avoid RAI ablation in selected PTC patients and to adjust low ablative doses in patients who are scheduled for remnant ablation.

Feasibility of the enhanced neuromuscular blockade recovery protocol with selective use of sugammadex in thyroid surgery with intraoperative neuromonitoring

BACKGROUND

To investigate feasibility of utilizing enhanced neuromuscular blocking agents with selective recovery protocol during thyroid surgery with intraoperative neuromonitoring (IONM).

METHODS

Two-hundred and ninety patients were randomized into two groups: group A 0.3 mg/kg rocuronium and group B 0.6 mg/kg. Sugammadex 2 mg/kg was injected if needed followed initial vagal stimulation (V0). Electromyography signals from vagus and recurrent laryngeal nerves before and after resection were recorded as V1, V2, R1, and R2.

RESULTS

In group B, 30 patients (20.7%) had V0 signals <100 μV, compared to 9 (6.2%) in group A. After sugammadex administration, 144 patients (99.3%) in both groups achieved positive V1 signals. Group B demonstrated a shorter surgical time from rocuronium injection to V2 stimulation compared to group A, accompanied by a significantly lower incidence of intraoperative body movement (0 vs. 16 patients).

CONCLUSIONS

0.6 mg/kg rocuronium with selective use 2 mg/kg sugammadex for IONM in thyroid surgery can meet both anesthesia and surgery demands.

Outcomes of Immediate Total Thyroidectomy in First-Side Loss of Neuromonitoring Signal

Importance

Use of intraoperative neuromonitoring (IONM) during thyroidectomy can nearly eliminate the risk of postoperative bilateral vocal cord palsy (VCP) by indicating staged surgery in cases of loss of signal (LOS) on the first side of planned total thyroidectomy. However, aborting planned total thyroidectomy may lead to persistence of symptoms, delay in adjuvant treatment, and patient inconvenience and distress. There are few data to guide a selective approach to total thyroidectomy in patients with first-side LOS.

Objective

To investigate outcomes of immediate bilateral surgery in patients undergoing total thyroidectomy with first-side LOS.

Design, Setting, and Participants

This cohort study was a retrospective review of outcomes for patients undergoing thyroidectomy between January 2016 and July 2023 at an academic tertiary referral center for thyroid surgery. Consecutive patients scheduled for total thyroidectomy using IONM were included. Exclusion criteria were preoperative VCP, deliberate sacrifice of recurrent laryngeal nerve (RLN), inadvertent RLN resection, and surgery performed without IONM.

Exposures

Total thyroidectomy performed using IONM.

Main Outcome Measures

Vocal mobility on first postoperative day as assessed by flexible laryngoscopy; secondary outcome measures included subjective voice assessment, other postoperative complications, and long-term vocal mobility.

Results

Among 400 patients undergoing planned total thyroidectomy (mean age, 50.5 years [range, 4-88 years]; 318 female [79.5%]), 51 (12.8%) had first-side LOS, of whom 37 (9.3%) had persistent LOS. Twenty-nine patients (56% of procedures with first-side LOS, including 18 with persistent LOS) proceeded to immediate total thyroidectomy. Postoperatively, 16 patients (55% of patients undergoing total thyroidectomy following first-side LOS, including 14 of 18 with persistent LOS) had impaired vocal mobility. One patient had bilateral VCP that did not require tracheostomy, and 2 had postoperative hypoparathyroidism. Of those whose surgery was aborted after first-side LOS, 8 of 22 (36%) underwent completion thyroidectomy at a later stage. In those undergoing completion thyroidectomy, 2 of 8 (25%) had temporary VCP after the second surgery, 2 (25%) had permanent hypoparathyroidism, and 1 (12.5%) developed inoperable cancer. Postoperative VCP was fully reversible in all but 1 patient.

Conclusion and Relevance

Among patients planned for total thyroidectomy who develop first-side LOS, immediate total thyroidectomy may be considered among those who have pressing reasons for same, and where surgical difficulties might be anticipated in a secondary surgery.

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.

Does the Use of Intraoperative Neuromonitoring during Thyroid and Parathyroid Surgery Reduce the Incidence of Recurrent Laryngeal Nerve Injuries? A Systematic Review and Meta-Analysis

Injury to the recurrent laryngeal nerve (RLN) can be a devastating complication of thyroid and parathyroid surgery. Intraoperative neuromonitoring (IONM) has been proposed as a method to reduce the number of RLN injuries but the data are inconsistent. We performed a meta-analysis to critically assess the data. After applying inclusion and exclusion criteria, 60 studies, including five randomized trials and eight non-randomized prospective trials, were included. A meta-analysis of all studies demonstrated an odds ratio (OR) of 0.66 (95% CI [0.56, 0.79], p < 0.00001) favoring IONM compared to the visual identification of the RLN in limiting permanent RLN injuries. A meta-analysis of studies employing contemporaneous controls and routine postoperative laryngoscopy to diagnose RLN injuries (considered to be the most reliable design) demonstrated an OR of 0.69 (95% CI [0.56, 0.84], p = 0.0003), favoring IONM. Strong consideration should be given to employing IONM when performing thyroid and parathyroid surgery.

The INMSG Survey on the Loss of Signal Management on the First Side During Planned Bilateral Thyroid Surgery

BACKGROUND

The aim of this study is to describe the management and associated follow-up strategies adopted by thyroid surgeons with different surgical volumes when loss of signal (LOS) occurred on the first side of planned bilateral thyroid surgery, and to further define the consensus on intraoperative neuromonitoring (IONM) applications.

METHODS

The International Neural Monitoring Study Group (INMSG) web-based survey was sent to 950 thyroid surgeons worldwide. The survey included information on the participants, IONM team/equipment/procedure, intraoperative/postoperative management of LOS, and management of LOS on the first side of thyroidectomy for benign and malignant disease.

RESULTS

Out of 950, 318 (33.5%) respondents completed the survey. Subgroup analyses were performed based on thyroid surgery volume: <50 cases/year (n = 108, 34%); 50 to 100 cases/year (n = 69, 22%); and >100 cases/year (n = 141, 44.3%). High-volume surgeons were significantly (P < .05) more likely to perform the standard procedures (L1-V1-R1-S1-S2-R2-V2-L2), to differentiate true/false LOS, and to verify the LOS lesion/injury type. When LOS occurs, most surgeons arrange otolaryngologists or speech consultation. When first-side LOS occurs, not all respondents decided to perform stage contralateral surgery, especially for malignant patients with severe disease (eg, extrathyroid invasion and poorly differentiated thyroid cancer).

CONCLUSIONS

Respondents felt that IONM was optimized when conducted under a collaborative team-based approach, and completed IONM standard procedures and management algorithm for LOS, especially those with high volume. In cases of first-site LOS, surgeons can determine the optimal management of disease-related, patient-related, and surgical factors. Surgeons need additional education on LOS management standards and guidelines to master their decision-making process involving the application of IONM.

A Comparison of Completeness and Complication of Total Thyroidectomy with or Without Neuromonitoring

Objectives

Total Thyroidectomy (TT) in true sense is not total as evidenced by remnant uptake in radio-iodine scans and serum thyroglobulin. The aim of this study is to assess the completeness of TT, operating time and recurrent laryngeal nerve injury with and without neuro-monitoring (IONM).

Methods

Cross sectional analytical study using retrospective data of patients undergoing total thyroidectomy for benign and malignant goiters. Surgeries performed by single surgeon. Patients undergoing TT (2015-22) were grouped into Group A (n = 400) and Group B (n = 400) based on use of IONM. Subgroup of patients (Group A1&B1) who had differentiated thyroid cancer were compared for completeness of thyroidectomy with DxWBS and serum thyroglobulin (TG). Group A and B were compared for operating time and incidence of RLN palsy.

Results

Of the 800 RLN at risk transient RLN palsy was lower with IONM (p = 0.048). Mean operating time was significantly higher in Group-B(p = 0.0038). Subgroup A1 showed lower radio-active iodine uptake percentage, higher number of patients with negative scan, TG of < 1ng/mL indicating better completeness of TT.

Conclusion

Our study shows better completeness of thyroidectomy, lower incidence of transient RLN palsy and shorter operating time with IONM.

Visualization of the recurrent laryngeal nerve alone versus intraoperative nerve monitoring in primary thyroidectomy: a framework approach to a missing typology

INTRODUCTION

Surgical studies evaluating a device or technology in comparison to an established surgical technique should accurately report all the important components of the surgical technique in order to reduce the risk of intervention bias. In the debate of visualization of the recurrent laryngeal nerve alone (VONA) versus intraoperative nerve monitoring (IONM) during thyroidectomy, surgical technique plays a key role in both strategies. Our aim was to investigate whether the surgical technique was considered as a risk of intervention bias by relevant meta-analyses and reviews and if steps of surgical intervention were described in their included studies.

METHODS

We searched PUBMED, CENTRAL-Cochrane library, PROSPERO and GOOGLE for reviews and meta-analyses focusing on the comparison of IONM to VONA in primary open thyroidectomy. Τhen, primary studies were extracted from their reference lists. We developed a typology for surgical technique applied in primary studies and a framework approach for the evaluation of this typology by the meta-analyses and reviews.

RESULTS

Twelve meta-analyses, one review (388,252 nerves at risk), and 84 primary studies (128,720 patients) were included. Five meta-analyses considered the absence of typology regarding the surgical technique as a source of intervention bias; 48 primary studies (57.14%) provided information about at least one item of the typology components and only 1 for all of them.

DISCUSSION

Surgical technique of thyroidectomy in terms of a typology is underreported in studies and undervalued by meta-analyses comparing VONA to IONM. This missing typology should be reconsidered in the comparative evaluation of these two strategies.

Place of laryngoscopy and neuromonitoring in thyroid surgery. Recommendations of the AFCE (Association francophone de chirurgie endocrinienne) with the SFE (Société française d'endocrinologie) and the SFMN (Société française de médecine nucléaire)

Preoperative laryngoscopy is mandatory when there is a history of cervical or thoracic surgery, dysphonia, posteriorly developed thyroid carcinoma, or significant lymph node involvement in the central compartment. Postoperative laryngoscopy should be performed for any postoperative dysphonia, swallowing difficulties, respiratory symptoms, or loss of signal during neuromonitoring of the recurrent and/or vagus nerve. Neuromonitoring can be useful in thyroid surgery because it lowers the rate of transient recurrent palsy (RP), although no impact on permanent RP has been demonstrated. It facilitates location of the recurrent nerve. Continuous neuromonitoring of the vagus nerve can, in some situations, allow early detection of a signal drop during dissection near the recurrent nerve.

Facelift thyroid surgery: a systematic review of indications, surgical and functional outcomes

OBJECTIVE

To investigate indications, surgical and functional outcomes of robotic or endoscopic facelift thyroid surgery (FTS) and whether FTS reported comparable outcomes of other surgical approaches.

DATA SOURCES

PubMed, Cochrane Library, and Scopus.

REVIEW METHODS

A literature search was conducted about indications, clinical and surgical outcomes of patients who underwent FTS using PICOTS and PRISMA Statements. Outcomes reviewed included age; gender; indications; pathology; functional evaluations; surgical outcomes and complications.

RESULTS

Fifteen papers met our inclusion criteria, accounting for 394 patients. Endoscopic or robotic FTS was carried out for benign and malignant thyroid lesions, with or without central neck dissection. Nodule size and thyroid lobe volume did not exceed 6, 10 cm, respectively. FTS reported comparable outcome with transaxillary or oral approaches about operative time, complication rates or drainage features. The mean operative time ranged from 88 to 220 min, depending on the type of surgery (endoscopic vs robotic hemi- or total thyroidectomy). Conversion to open surgery was rare, occurring in 0-6.3% of cases. The most common complications were earlobe hypoesthesia, hematoma, seroma, transient hypocalcemia and transient recurrent nerve palsy. There was an important disparity between studies about the inclusion/exclusion criteria, surgical and functional outcomes.

CONCLUSION

FTS is a safe and effective approach for thyroid benign and malignant lesions. FTS reports similar complications to conventional thyroidectomy and excellent cosmetic satisfaction.

Proving the Superiority of Intraoperative Recurrent Laryngeal Nerve Monitoring over Visualization Alone during Thyroidectomy

Vocal fold paralysis after thyroid surgery is still a dangerous complication that significantly reduces patients’ quality of life. Since the intraoperative neuromonitoring (IONM) technique has been introduced and standardized, the most frequently asked question is whether its use has significantly reduced the rate of RLN injury during thyroid surgery compared to visual identification alone (VA). The aim of this study was to attempt to prove the superiority of IONM over VA of the RLN during thyroid surgery in the prevention of vocal fold paralysis, taking into account risk factors for complications. The medical records of 711 patients (1265 recurrent laryngeal nerves at risk of injury) were analyzed retrospectively: in 257 patients/469 RLNs at risk, thyroid surgery was performed with IONM; in 454 patients/796 RLNs at risk, surgery was performed with VA. The statistical analysis showed that in the group of patients with IONM only one risk factor—the surgeon’s experience—proved statistically significant (OR = 3.27; p = 0.0478) regarding the overall risk of vocal fold palsy. In the group of patients where only visualization was used, 5 of the 12 factors analyzed were statistically significant: retrosternal goiter (OR = 2.23; p = 0.041); total thyroid volume (OR = 2.30; p = 0.0284); clinical diagnosis (OR = 2.5; p = 0.0669); gender (OR = 3.08; p = 0.0054) and risk stratification (OR = 3.30; p = 0.0041). In addition, the cumulative risk, taking into account the simultaneous influence of all 12 factors, was slightly higher in the group of patients in whom only VA was used during the procedure: OR = 1.78. This value was also considerably more statistically significant (p < 0.0001) than that obtained in the group of patients in whom IONM was used: OR = 1.73; p = 0.004. Conclusions: Risk factors for complications in thyroid surgery are not significant for any increase in the rate of vocal fold paralysis as long as surgery is performed with IONM, in contrast to thyroid surgery performed only with VA, thus proving the superiority of IONM over VA for safety.

Pediatric thyroid surgery: Retrospective analysis on the first 25 pediatric thyroidectomies performed in a reference center for adult thyroid diseases

Introduction

Pediatric thyroid carcinoma represents about 4-5% of all pediatric carcinoma with an incidence of 0.5 cases/100,000, compared to 2-10/100000 cases in the adult population. The aim of this study is to present the experience of a reference adult endocrine surgery unit in charge of the treatment of pediatric thyroid diseases.

Materials and methods

From January 2019 to September 2022, 25 patients, aged 5-17, underwent thyroid surgery. We analysed indications for surgery, use of intraoperative nerve monitoring (IONM), definitive histological examination, postoperative outcomes and risk factors related.

Results

Surgical indication was performed for Graves' disease (27%) and for nodular pathology (73%): of these, four were malignant lesions (TIR4/TIR5), eight with indeterminate characteristics (TIR3A/TIR3B) and four characterized as benign (TIR1/TIR2). Total thyroidectomy (TT) was performed in 76% of cases, three of which were prophylactic for the activation of the RET gene mutation in MEN 2A. IONM was used in eight cases (32%), all patients aged 11 years or less. FNA's accuracy was 100% for lesions typified as benign and malignant (TIR1/TIR2 and TIR4/TIR5). The overall malignancy rate achieved was 40% and in the final histological examination 75% of the TIR 3B lesions were malignant. Six patients (24%) developed hypoparathyroidism in the first postoperative day, with normalization of calcium values within thirty days in 5 patients.

Conclusions

Pediatric thyroid nodules are rare and distinguished from adult thyroid disease by a worse prognosis and higher malignancy rates. Our work reports a much higher malignancy rate among indeterminate TIR 3B lesions than observed in the adult population and the three patients who underwent prophylactic total thyroidectomy for activating RET gene mutation had all a definitive histological diagnosis of medullary carcinoma. Post-surgical hypoparathyroidism is a common finding in these patients: in most cases the condition is transient and it benefits from supportive therapy. Intraoperative finding of a thinner recurrent laryngeal nerve in younger patients makes nerve isolation more difficult than in adult surgery: IONM is recommended in patients under 12. Pediatric thyroid surgery is challenging, we sustain it requires referral thyroid Centers for thyroid disease with highly skilled general endocrine surgeons.

Is There Any Reliable Predictor of Functional Recovery Following Post-thyroidectomy Vocal Fold Paralysis?

BACKGROUND

Predicting definitive outcomes of post-thyroidectomy vocal fold paralysis (VFP) is challenging. We aimed to identify reliable predictors based on intraoperative neuromonitoring (IONM) and flexible fiberoptic laryngostroboscopy (FFL) findings.

METHODS

Among 1172 thyroid operations performed from April to December 2021, all patients who exhibited vocal fold paralysis (VFP) at post-operative laryngoscopy were included. IONM data, including type of loss of signal (LOS), were collected. Patients underwent FFL, with arytenoid motility assessment, at 15, 45 and 120 days post-operatively. Patients were divided into two groups: those who recovered vocal fold motility (VFM) by the 120th post-operative day (recovery group) and those who did not (non-recovery group).

RESULTS

Fifty-nine VFP cases (5.0% of total patients) met the inclusion criteria. Eight patients were lost at follow-up and were excluded. Overall, 9 patients were included in the non-recovery group (0.8% of total patients) and 42 in the recovery group. Among various predictive factors, only arytenoid fixation (AF) at the 15th post-operative day and Type I LOS were significant predictors for no VFM recovery (p = 0.007, RR = 9.739, CI:1.3-72.3 and p = 0.001, RR = 9.25, CI:2.2-39.3 for AF and Type I injury, respectively). The combination of type of LOS and arytenoid motility at the 15th post-op day yielded satisfactory predictive values for the progression of transient VFP to permanent.

CONCLUSIONS

Arytenoid motility at the 15th post-op day and type II LOS are associated with recovery of VFM. Type of LOS and FFL could be included in the follow-up protocols of patients with VFP to reliably predict clinical outcomes.

Intraoperative Neuromonitoring for Thyroid Surgery in Children and Adolescents: A Single Center Experience

Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) has been shown in adults to minimize nerve palsy after thyroid surgery, but only few studies on its efficacy in a pediatric population have been reported. We conducted a retrospective study on patients operated for thyroid lesions from 2016 to 2022. The analyzed population was divided in two groups: patients treated from 2016 to 2020, when the identification of the RLN was performed without IONM (Group A); and patients treated since 2021, when IONM was implemented in every surgical procedure on the thyroid (Group B). Intraoperative Neurophysiological Monitoring was performed by using corticobulbar motor-evoked potentials and continuous electromyography. Twentyfive children underwent thyroid resection, 19 (76%) of which due to thyroid carcinoma. Each patient's recurrent nerve was identified; IONM was used in 13 patients. In Group A, one temporary nerve palsy was identified postoperatively (8.3%), while in group B one nerve dysfunction occurred (7.7%). No statistically significant difference was found between the two groups in terms of post-operative RLN palsy. No surgical complication due to the use of IONM was reported. In children and teenagers, intraoperative neuromonitoring of the recurrent laryngeal nerve is a safe and accurate method, minimizing the risk of nerve damage.

Discrepancies in Thyroidectomy Outcomes Between General Surgeons and Otolaryngologists

Thyroidectomy is a common operation, performed by general surgeons and otolaryngologists. Few studies compare complication rates between these two specialties. We hypothesized that there would be no difference in the incidence of postoperative complications including recurrent laryngeal nerve (RLN) injury, hypocalcemia, or hematoma based on the surgical specialty performing the thyroidectomy. The 2016-2017 National Surgical Quality Improvement Program Targeted Thyroidectomy database was queried for patients who underwent thyroidectomy for both benign and malignant thyroid diseases. Thyroidectomies performed by general surgeons were compared to those performed by otolaryngologists. Multivariate logistic regression was used to identify risk factors associated with RLN injury, hematoma, and hypocalcemia. From 11,595 patients, 6313 (54.4%) were performed by general surgeons and 5282 (45.6%) by otolaryngologists. Goiter (43.7%) and nodule/neoplasm (40.8%) were the most common indications for the general surgery and otolaryngology cohorts respectively. General surgeons used an energy vessel sealant device more frequently (77.7% vs. 51.5%, p < 0.001), whereas RLN monitoring (67.4% vs. 58.3%, p < 0.001) and drain placement (44.3% vs. 14.8%, p < 0.001) were utilized more often by otolaryngology. After controlling for covariates, thyroidectomy by general surgeons had an increased associated risk of RLN injury (OR = 1.26, CI = 1.07-1.48, p = 0.006) and post-operative hypocalcemia (OR = 1.17, CI = 1.00-1.37, p = 0.046). Thyroidectomy volume is relatively equally distributed among general surgeons and otolaryngologists. Operation by a general surgeon is associated with an increased risk for RLN injury and postoperative hypocalcemia. This discrepancy may be explained by case volume, training, and/or completion of an endocrine surgery fellowship; however, this discrepancy still merits ongoing attention.

Intraoperative Neuromonitoring and Optical Magnification in the Prevention of Recurrent Laryngeal Nerve Injuries during Total Thyroidectomy

Background and Objectives: Recurrent laryngeal nerve (RLN) paralysis is a fearful complication during thyroidectomy. Intraoperative neuromonitoring (IONM) and optical magnification (OM) facilitate RLN identification and dissection. The purpose of our study was to evaluate the influence of the two techniques on the incidence of RLN paralysis and determine correlations regarding common outcomes in thyroid surgery. Materials and Methods: Two equally sized groups of 50 patients who underwent total thyroidectomies were examined. In the first group (OM), only surgical binocular loupes (2.5×−4.5×) were used during surgery, while in the second group (IONM), the intermittent NIM was applied. Results: Both the operative time and the length of hospitalization were shorter in the OM group than in the IONM group (median 80 versus 100 min and median 2 versus 4 days, respectively) (p < 0.05). The male patients were found to have a five-fold higher risk of developing transient dysphonia than the females (adjusted OR 5.19, 95% IC 0.99−27.18, p = 0.05). The OM group reported a four-fold higher risk of developing transient hypocalcemia than the IONM group (OR 3.78, adjusted OR 4.11, p = 0.01). Despite two cases of temporary bilateral RLN paralysis in the IONM group versus none in the OM group, no statistically significant difference was found (p > 0.05). No permanent RLN paralysis or hypoparathyroidism have been reported. Conclusions: Despite some limitations, our study is the first to compare the use of IONM with OM alone in the prevention of RLN injuries. The risk of recurrent complications remains comparable and both techniques can be considered valid instruments, especially if applied simultaneously by surgeons.

Clinical Outcome of Intraoperative Recurrent Laryngeal Nerve Monitoring during Thoracoscopic Esophagectomy and Mediastinal Lymph Node Dissection for Esophageal Cancer

Mediastinal lymph dissection in esophagectomy for patients with esophageal cancer is important. The dissection of recurrent laryngeal nerve (RLN) lymph nodes could cause RLN injury, vocal cord palsy, pneumonia, and respiratory failure. This retrospective study aimed to evaluate the effects of intraoperative RLN monitoring in esophagectomy and mediastinal lymph node dissection in preventing RLN injury and vocal cord palsy. This study included 75 patients who underwent minimally invasive esophagectomy and mediastinal lymph node dissection for esophageal cancer with (38 patients) and without (37 patients) IONM at Changhua Christian Hospital from 2015 to 2020. The surgical and clinical outcomes were reviewed. Patients in the IONM group had more advanced clinical T status, shorter operation time (570 vs. 633 min, p = 0.007), and less blood loss (100 mL vs. 150 mL, p = 0.019). The IONM group had significantly less postoperative vocal palsy (10.5% vs. 37.8%, p = 0.006) and pneumonia (13.2% vs. 37.8%, p = 0.014) than that in the non-IONM group. IONM was an independent factor for less postoperative vocal cord palsy that was related to postoperative 2-year survival. This study demonstrated that IONM could reduce the incidence of postoperative vocal cord palsy and pneumonia.

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.

Effect of Intraoperative Neuromonitoring on the Risks of Recurrent Laryngeal Nerve Injury During Thyroidectomy: A Doubly Robust Approach

OBJECTIVE

To evaluate the relationship between the use intraoperative neuromonitoring (IONM) during thyroidectomy and the risk of recurrent laryngeal nerve (RLN)injury.

BACKGROUND

The role of IONM in reducing RLN injury during thyroidectomy remains controversial. Several studies on this topic apply conventional multivariable regression to adjust for confounding. However, estimates from this method may be biased due to model misspecification, especially with a rare outcome such as RLN injury.

METHODS

We used a pooled dataset created by linking the 2016 - 2019 NSQIP General Participant User File with the corresponding Targeted-Thyroidectomy file. The primary outcome was RLN injury rates, and the secondary outcomes were operating time and postoperative length of stay. A doubly robust (DR) estimator, in the form of an inverse-probability-weighted regression adjustment model, was used to estimate the effect of the use of IONM on the risk of RLN injury. Sensitivity analyses was performed.

RESULTS

Twenty-four thousand three hundred seventy patients were evaluated, out of which 15,836 (70%) patients had IONM during thyroidectomy, and RLN injury occurred in 1,498 (6.2%) cases. Rates of RLN injury increase with increasing age and BMI and are higher in patients with a cancer diagnosis, previous neck operation, total thyroidectomy, and node dissection. DR model suggests that the use of IONM was associated with a significant reduction in overall rate of RLN injury (RR 0.77(CI, 0.68 to 0.87),P<0.001], and postoperative length of stay [-2.5 h(CI, -4.18 to - 0.81 h)P=0.004)]. However, IONM use was associated with an increase in operating time [15.41mins(CI, 13.29-14.54 mins, P<0.0001)]. Sensitivity analyses revealed that our estimates are largely robust to confounding.

CONCLUSION

In a balanced cohort of patients undergoing thyroidectomy from multiple sites and surgeons participating in NSQIP, the use of IONM during thyroidectomy was associated with reduction in RLN injury.

Utility of the continuous intraoperative neuromonitoring in the prevention of the recurrent laryngeal nerve paralysis during thyroid surgery. 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.

Revision Thyroid Surgery

The incidence of recurrence in well-differentiated thyroid malignancies range from 10 to 30%. It is estimated that about 31-46% of patients with differentiated thyroid cancer will have the persistent disease and 1.2-6.8% will have structural recurrences during post-operative monitoring, depending on the initial therapy and prognostic variables. It is challenging to decide on treatment versus active monitoring following repeated or persistent tumour detection. The biological factors of the tumour and the patient guide us in the overall decision-making. Revision thyroid surgery is technically challenging. The morbidity encountered during the revision surgery is related to the anatomy of the region undergoing dissection, the degree of fibrosis and scarring from prior surgery and the operating surgeon's experience. Successful comprehensive management of revision thyroid surgery needs a multi-disciplinary approach. This review article highlights the definition, indications for revision surgery, identification of recurrent disease, management of parathyroid and recurrent laryngeal nerves with neuromonitoring.

Importance of Intraoperative Neuromonitoring Parameters in Predicting Temporary Recurrent Laryngeal Nerve Palsy Following Thyroid Surgery for Malignancy

Recurrent laryngeal nerve (RLN) palsy is one of the feared complications following thyroid surgery. Intraoperative neuromonitoring (IONM) has been used as an adjunct to reduce this complication. In the present study, we attempted to evaluate the IONM parameters such as latency, current requirement, and baseline amplitude that could predict temporary RLN palsy along with factors that could influence these parameters during thyroid surgery. This was a retrospective study of patients who underwent hemi, total, or completion thyroidectomy for cancer at our institute between June 1, 2017 to May 31, 2019 in whom IONM was used during surgery. The study consisted of 84 consecutive patients with 138 nerves at risk. The RLN palsy rate in our study was 5% (n = 7). Patients with low baseline amplitude and/or requiring higher current to maintain normal baseline amplitude were often associated with temporary RLN palsy. In the multivariate analysis, age > 40 years (p = 0.001, OR = 4.14) influenced the baseline EMG amplitude the most. The intraoperative current management was influenced by advanced pT stage (p = 0.001, OR = 2.87), and structural nerve injury (p = 0.001, OR = 3.15). Patients with low baseline amplitude and/or requiring higher current to maintain normal baseline amplitude were often associated with temporary RLN palsy. Factors such as age, pT stage, and structural nerve injury influenced the IONM stimulation and recording parameters.

Seeing Is Not Believing: Intraoperative Nerve Monitoring (IONM) in the Thyroid Surgery

Ensuring the integrity of the recurrent laryngeal nerve (RLN), the external branch of superior laryngeal nerve (EBSLN) and preservation of normal voice are the prime 'functional' goals of thyroid surgery. More in-depth knowledge of neuronal mechanisms has revealed that anatomical integrity does not always translate into functional integrity. Despite meticulous dissection, neural injuries are not always predictable or visually evident. Intraoperative nerve monitoring (IONM) is designed to aid in nerve identification and early detection of functional impairment. With the evolution of technique, intermittent monitoring has given way to continuous-IONM. Over the years, IONM gathered both support and flak. Despite numerous randomised studies, systematic reviews, and meta-analyses, there still prevails a state of clinical equipoise concerning the utility of IONM and its cost-effectiveness. This article inspects the true usefulness of IONM, elaborates on the optimal way to practice it, and presents a critical literature review.

The Role of Anatomical Imaging and Intraoperative Neuromonitoring (IONM) for Successful Prediction of a Nonrecurrent Laryngeal Nerve

A nonrecurrent laryngeal nerve (NRLN) is a rare anatomical variant of laryngeal nerves that branches directly from the vagus nerve. The anatomical abnormality makes it difficult to identify the NRLN and results in high incidence of accidental nerve injury during surgery. A 76-year-old woman complained of swelling in the right side of her neck and visited our university hospital for further examination. Ultrasonography showed a right thyroid lobe mass with calcification and fine needle aspiration biopsy was classified as class III. Computed tomography revealed that the right subclavian artery branched directly from the descending aorta without branching from the brachiocephalic artery and ran behind the esophagus. Since it was afraid that the accidental injury of NRLN was likely to occur, a right thyroid lobe dissection using intraoperative neuromonitoring (IONM) was performed. After separating the connective tissue on the thyroid capsule from the right side of the trachea to the inferior pole laterally, the NRLN running across the level of the inferior margin of the cricoid cartilage was identified by using IONM 0.5 mA stimulation. After complete dissection of right thyroid lobe, we again stimulated the NRLN by 0.5 mA and the electromyographic response was confirmed. The pathological analysis confirmed nodular hyperplasia without malignancy; the condition was diagnosed as an adenomatous goiter. There was no vocal cord dysfunction and hoarseness after the surgery. IONM contributed to the prevention of NRLN injury during the surgery. We believe that it is important to confirm the presence or absence of an aberrant subclavian artery on preoperative imaging, and that IONM should be considered to identify the NRLN to prevent vocal cord paralysis if its presence is suspected.

Intraoperative Neuromonitoring: Evaluating the Role of Continuous IONM and IONM Techniques for Emerging Surgical and Percutaneous Procedures

Intraoperative nerve monitoring (IONM) is a tool used during thyroid surgery to assist in the identification of the recurrent laryngeal nerve (RLN). Multiple IONM systems that exist for thyroidectomy require intubation with an endotracheal tube. Given that one of the advantages of thermal ablation procedures, such as radiofrequency ablation, is that they can be done safely without the use of general anesthesia, nerve monitoring systems that utilize cutaneous surface electrodes have been developed, though are not widely available in the United States. This article will review the use of IONM for RFA including the cutaneous surface electrode system.

Intraoperative Neuromonitoring: Evaluating the Role of Continuous IONM and IONM Techniques for Emerging Surgical and Percutaneous Procedures

Continuous and intermittent intraoperative nerve monitoring (IONM) has become an important asset for endocrine surgeons over the past few decades. The ability to determine neurophysiologic integrity of the recurrent laryngeal nerve (RLN) and external branch of the superior laryngeal nerve (EBSLN) on top of identification and meticulous dissection of the nerve in the surgical field, has allowed for advances in technology and improved outcomes when it comes to prevention of vocal fold immobility. This article aims to compare in review continuous and intermittent nerve monitoring (CIONM, IIONM), as well as review the current paradigms of their use. This article will also discuss the future of intraoperative nerve monitoring technologies in scarless thyroid surgery and percutaneous approaches to thyroid pathology in form of radiofrequency ablation (RFA).

The value of intraoperative nerve monitoring against recurrent laryngeal nerve injury in thyroid reoperations

Reoperative thyroidectomy is challenging for surgeons because of the higher incidence of recurrent laryngeal nerve (RLN) palsy. RLN identification is the gold standard during thyroidectomy; however, it is sometimes difficult to perform thyroid reoperations. In recent years, intraoperative nerve monitoring (IONM) has gained increased acceptance, and the use of IONM can be a valuable adjunct to visual identification. The aim of this study was to evaluate the value of IONM during thyroid reoperation.A total of 109 patients who met our criteria at the Affiliated Hospital of Hangzhou Normal University from January 2010 to June 2020 were retrospectively analyzed and divided into the IONM group and the visualization-alone group (VA group) according to whether neuromonitoring was used during the operation. The patients' characteristics, perioperative data, and intraoperative information including the RLN identification, time of RLNs confirmation, operative time, intraoperative blood loss, and the rate of RLN injury were collected.Sixty-five procedures (94 RLNs at risk) were performed in the IONM group, whereas 44 (65 RLNs at risk) were in the VA group. The rate of RLN identification was 96.8% in the IONM group and 75.4% in the VA group (P < .05). The incidence of RLN injury was 5.3% in the IONM group and 13.8% in the VA group (P > .05). The incidence of surgeon-related RLN injury rate was 0% in the IONM group compared to 7.7% in the VA group (P < .05), but the tumor-related or scar-related RLN injury rate between the 2 groups were not significantly different (4.3% vs 3.1%, 1.1% vs 3.1%, P > .05).IONM in thyroid reoperation was helpful in improving the RLN identification rate and reducing the surgeon-related RLN injury rate, but was ineffective in reducing the tumor-related and scar-related RLN injury rate. In the future, multicenter prospective studies with large sample sizes may be needed to further assess the role of IONM in thyroid reoperations.

Evaluation of the clinical value of carbon nanoparticles in endoscopic thyroidectomy and prophylactic central neck dissection through total mammary areolas approach for thyroid cancer

Background

Carbon nanoparticles (CNs) are tracers used in thyroid surgery of patients with thyroid cancer (TC) to help remove lymph nodes and protect the parathyroid gland. The facilitative effect of carbon nanoparticles in endoscopic thyroidectomy and prophylactic central neck dissection (pCND) has not been reported.

Methods

The protective effect on parathyroid gland (PG) function and the numbers of identified parathyroid glands and central lymph nodes in endoscopic thyroid surgery through the total mammary areolas approach were compared between the CN and control groups.

Results

All endoscopic thyroidectomies were successfully completed. No difference was found in either group regarding the general characteristics or operative complications. The mean number of superior PGs and inferior PGs identified in situ or in the dissected central lymph tissues was not different between the groups. The mean number of lymph nodes removed by unilateral CND was greater in the CN group than in the control group. However, there was no difference in the number of harvested lymph nodes when excluding the LNs less than 5 mm, which exhibit an extremely low metastatic rate.

Conclusion

Carbon nanoparticles do not improve the protective effect on the parathyroid gland, especially the inferior glands, in endoscopic thyroid surgery through the total mammary areolas approach. There is no need to use CNs to facilitate the lymph node harvest in endoscopic prophylactic unilateral CND.

Success rate and learning curve of intraoperative neural monitoring of the external branch of the superior laryngeal nerve in thyroidectomy

BACKGROUND

This study aimed to evaluate the success rate and learning curve of intraoperative neural monitoring (IONM) of the external branch of the superior laryngeal nerve (EBSLN) in thyroidectomy.

METHODS

We studied 130 consecutive patients (200 nerves at risk [NARs]) who had undergone conventional thyroidectomy with IONM of the recurrent laryngeal nerve (RLN) and EBSLN from January 2017 to March 2020. The learning curve was defined as the number of NARs required to achieve an effective and reliable neuromonitoring rate.

RESULTS

IONM of the EBSLN was successful in 136/200 (68%) NARs. The cutoff point of the learning curve was 45 NARs (28 patients). The neural identification rate of EBSLN was significantly higher in the post-learning 155 NARs group than the pre-learning group (82.6% vs. 17.8%, p < 0.001).

CONCLUSIONS

Approximately 45 NAR neuromonitoring attempts were required to reach a significant increase in the EBSLN identification rate and overcome the learning curve.

Technological Advances Have Improved Surgical Outcome in Thyroid Surgery: Myth or Reality?

Aim

In this study, we aimed to investigate the effects of Ultrasonic Coagulation (UC), Bipolar Energy Sealing System (BESS), Intra Operative Nerve Monitoring (IONM) and surgical experience on the complications of thyroid surgery.

Method

The data of 1627 patients who underwent thyroid surgery for various indications in our department between 2009 and 2018 were analyzed retrospectively and the effects of different technological devices on complications were investigated.

Results

Transient recurrent laryngeal nerve (RLN) palsy was higher between 2009 and 2013, when IONM was not in routine use (p=0.029). There were no significant differences between two energy devices (UC and BESS) in terms of transient or permanent RLN palsy, bleeding, and transient or permanent hypocalcemia. Multivariate analysis showed that young age (0.006), female gender (0.016), surgery type (p<0.001), and lateral neck dissection (p=0.026) are independent risk factors for transient hypocalcemia.

Conclusion

The results indicate that there is no superior hemostatic device. IONM and specific branching decrease transient RLN palsy. Female gender, young age, completion thyroidectomy, and lateral neck dissection were independent risk factors for the development of transient hypocalcemia.

Dosage effect of cisatracurium on intubation and intraoperative neuromonitoring during thyroidectomy: a randomized controlled trial

Background

Intraoperative neuromonitoring (IONM) reduces the risk of recurrent laryngeal nerve (RLN) injury during thyroid surgery. However, the use of neuromuscular blocking agents (NMBAs), which are essential to improve intubation conditions, may hinder the electromyographic response during IONM. The aim of this prospective, double-blind, randomized controlled trial was to explore the optimal dosage of cisatracurium to produce adequate muscle relaxation for tracheal intubation without significantly affecting evoked potentials of IONM during thyroidectomy.

Methods

Patients undergoing thyroidectomy with IONM in our institution, with an American Society of Anesthesiologists grade of I-II, aged 18-75 years, and with a body mass index below 32 kg/m² were enrolled and randomly assigned (by random numbers) to receive 1× (group C1) or 2× (group C2) the effective dose (ED₉₅) of cisatracurium for tracheal intubation. The patients, surgeons, and anesthesiologists in charge were blinded to group assignment. Anesthesia was induced with sufentanil, propofol, and cisatracurium (0.05 mg/kgin group C1, 0.1 mg/kg in group C2). Ease of intubation was evaluated with the intubation condition score (Cooper score) and the intubation difficulty scale (IDS). Amplitudes of evoked potentials during intermittent IONM were compared between groups. The primary outcomes were the Cooper score, the IDS score, and the evoked potentials of IONM.

Results

Fifty-three patients were randomized from October 2019 to November 2020, and 52 were analyzed (with 26 patients in each group). The Cooper score was significantly lower in group C1 [median, 8.0 (interquartile range, 7.0-8.3)] than in group C2 [9.0 (9.0-9.0), P<0.001]. The rate of difficult laryngoscopy without external laryngeal pressure was significantly higher in group C1 than in group C2 (61.5% vs. 11.5%, P<0.001). More patients in group C1 required assistance to complete tracheal intubation (16 vs. 4, P=0.001). The IDS score was significantly higher in group C1 [3.0 (0.0-4.0) vs. 1.0 (0.0-1.0), P=0.045]. There were no significant differences between groups in amplitudes of evoked potentials. No serious adverse events were observed.

Conclusions

A dose of 2× ED₉₅ of cisatracurium provided better intubation conditions and easier tracheal intubation than 1× ED₉₅, without disturbing IONM.

Trial Protocol

Chinese Clinical Trial Registry (No. ChiCTR1900022884).

Sinus pause during nerve integrity monitoring tube insertion following anesthetic induction with a low-dose neuromuscular blocking agent: A CARE-compliant case report

RATIONALE

Nerve integrity monitoring (NIM) tubes are commonly used in thyroid surgery to prevent recurrent laryngeal nerve injury. To achieve the optimal electromyographic signal for NIM as intraoperative neural monitoring (IONM), the neuromuscular blocking agent (NMBA) dose should be low. The use of a low-dose NMBA increases the anesthetic and analgesic agent dose required to attenuate the laryngeal reflex during intubation. In addition, since the NMBA onset time is delayed, depending on the situation, anesthesia may become excessively deep or shallow before intubation.

PATIENTS CONCERN

A 51-year-old woman scheduled for thyroid lobectomy received 0.3 mg/kg of rocuronium. Three minutes later, when the NIM tube was inserted through the vocal cord, the patient's heart rate (HR) was undetectable for 2 seconds.

DIAGNOSIS

We suspected that the use of a high-dose anesthetic agent and remifentanil or the laryngocardiac reflex induced the sinus pause.

INTERVENTIONS

To maintain the anesthetic depth, we administered 6 vol% of desflurane. Because the patient's systolic blood pressure was 70 mmHg and HR was 30 beats/min, we discontinued the remifentanil infusion and administered 8 mg of ephedrine.

OUTCOMES

The patient's vital signs recovered to normal levels. Subsequently, there were no episodes of bradycardia or arrhythmia.

CONCLUSION

Sinus pause or severe bradycardia may occur due to the laryngocardiac reflex or the administration of a high-dose anesthetic and analgesic agent during tracheal intubation in patients who received a low-dose NMBA for IONM induction using an NIM tube. Anesthesiologists should be aware of these risks and take precautions to maintain adequate anesthesia, be prepared to administer vasoactive drugs to increase the blood pressure and HR if needed, and, if possible, intravenously administer lidocaine to attenuate the laryngeal reflex during intubation.

Surgical Skills and Technological Advancements to Avoid Complications in Lateral Neck Dissection for Differentiated Thyroid Cancer

Neck dissection is a surgical procedure reserved for thyroid cancer cases with clinically evident lymphatic invasion. Although neck dissection is a reliable and safe procedure, it can determine a significant morbidity involving a variety of structures of nervous, vascular and endocrine typology. A careful pre-operative study is therefore essential to better plan surgery. Surgical experience, combined with accurate surgical preparation and merged with adequate and specific techniques, can certainly help reduce the percentage of complications. In recent years, however, technology has also proved to be useful. Its crucial role was already recognized in the safeguard of the integrity of the laryngeal nerve through neuro-monitoring, but new technologies are emerging to help the preservation also of the parathyroid glands and other structures, such as the thoracic duct. These surgical skills combined with the latest technological advancements, that allow us to reduce the incidence of complications after neck dissection for thyroid cancer, will be reported in the present article. This topic is of significant interest for the endocrine and metabolic surgeons' community.

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.

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

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

Intraoperative spinal accessory nerve monitoring in neck dissections

BACKGROUND

The identification and preservation of the spinal accessory nerve (SAN) is essential in neck surgeries due to possible complications. We report the technique to intraoperative neuromonitoring (IONM) of SAN in functional neck dissections.

METHOD

SAN was monitored by needle electrodes placed on the trapezius muscle. Preoperative and postoperative nerve mapping was performed.

CONCLUSION

IONM for spinal accessory nerve in patients undergoing neck dissection is a useful technique that can be valuable for neck surgeries where spinal nerve injury is at risk.

Role of intraoperative neuromonitoring of recurrent laryngeal nerve in thyroid and parathyroid surgery

Objective

To investigate whether intraoperative neuromonitoring (IONM) has a significant advantage in reducing the incidence of recurrent laryngeal nerve (RLN) injury.

Methods

Patients who underwent thyroid and parathyroid surgery from October 2012 to December 2017 at the Center for Thyroid and Breast Surgery of Xuanwu Hospital were retrospectively analyzed. They were divided into the IONM group and visualization alone group (VA group) according to whether IONM was used.

Results

In total, 1696 nerves at risk of injury (IONM group, n = 1104; VA group, n = 592) were included in the analysis. Among the high-risk nerves, permanent damage occurred in no cases in the IONM group but in one case in the VA group. Because the higher proportion of central lymph node metastasis caused difficulties in central cervical lymph node dissection and identification of the RLN, the patients undergoing lateral cervical lymph node dissection in the VA group had a significantly higher risk of postoperative RLN injury (11.76% vs. 0.00%).

Conclusion

IONM technology has advantages in protection of the RLN, especially in high-risk nerves and patients with a high proportion of central lymph node metastasis who require central and lateral cervical lymph node dissection.

Intraoperative nerve monitoring in thyroid surgery: analysis of United Kingdom registry of endocrine and thyroid surgery database

BACKGROUND

Intraoperative nerve monitoring (IONM) is used increasingly in thyroid surgery to prevent recurrent laryngeal nerve (RLN) injury, despite lack of definitive evidence. This study analysed the United Kingdom Registry of Endocrine and Thyroid Surgery (UKRETS) to investigate whether IONM reduced the incidence of RLN injury.

METHODS

UKRETS data were extracted on 28 July 2018. Factors related to risk of RLN palsy, such as age, sex, retrosternal goitre, reoperation, use of energy devices, extent of surgery, nodal dissection and IONM, were analysed. Data with missing entries for these risk factors were excluded. Outcomes of patients who had preoperative and postoperative laryngoscopy were analysed.

RESULTS

RLN palsy occurred in 4.9 per cent of thyroidectomies. The palsy was temporary in 64.6 per cent and persistent in 35.4 per cent of patients. In multivariable analysis, IONM reduced the risk of RLN palsy (odds ratio (OR) 0.63, 95 per cent confidence interval (CI) 0.54 to 0.74, P < 0.001) and persistent nerve palsy (OR 0.47, 0.37 to 0.61, P < 0.001). Outpatient laryngoscopy was also associated with a reduced incidence of RLN palsy (OR 0.50, 0.37 to 0.67, P < 0.001). Bilateral RLN palsy occurred in 0.3 per cent. Reoperation (OR 12.30, 2.90 to 52.10, P = 0.001) and total thyroidectomy (OR 6.52, 1.50 to 27.80; P = 0.010) were significantly associated with bilateral RLN palsy.

CONCLUSION

The use of IONM is associated with a decreased risk of RLN injury in thyroidectomy. These results based on analysis of UKRETS data support the routine use of RLN monitoring in thyroid surgery.

Unmapped landmarks around branches of the Superior Laryngeal Nerve: An exploratory cadaveric study

Objectives

Preserving the External Branch of Superior Laryngeal Nerve (EBSLN) and Internal Branch of Superior Laryngeal Nerve (IBSLN) is essential during thyroidectomy. However, due to potential distortions caused by large goitres, the present anatomical landmarks used to identify these nerves are flawed. Although under such circumstances, bony landmarks may offer more stable reference points, not much has been explored in this regard. This study measures the distance between the most vulnerable points of the EBSLN and IBSLN and their relatively unexplored bony landmarks, such as the hyoid bone and thyroid notch as well as soft-tissue landmarks like the origin of the Superior Thyroid Artery (STA) and carotid bifurcation.

Methods

An exploratory cadaveric study was conducted in a medical school affiliated with a tertiary care hospital. The detailed analysis included 13 sides from 8 cadavers.

Results

The average distance from the EBSLN piercing site to the greater cornua of the hyoid bone, thyroid cartilage prominence, origin of the STA, and carotid bifurcation was 35.1(±7.2) mm, 33.3(±3.8) mm, 25.7(±6.3) mm, and 31.5(±5.0) mm, respectively and from the IBSLN piercing site was 15.9(±5.9) mm, 32.9(±4.7) mm, 16.3(±4.2) mm, and 20.7(±5.9) mm, respectively. For most cadavers, the distal EBSLN had Cernea type 2a-like relationship with the STA. Certain variations were also observed in the way these nerves branched with respect to the origin of the STA.

Conclusions

This study provides metric information (linear measurements) regarding the distance between the branches of SLN and certain unique landmarks. This could potentially aid in minimising intraoperative trauma to these branches.

Application of carbon nanoparticles combined with intraoperative neuromonitoring in papillary thyroid microcarcinoma surgery

PURPOSES

To improve the lymph node dissection as well as protect parathyroid gland and recurrent laryngeal nerve, the carbon nanoparticles and intraoperative neuromonitoring were applied in papillary thyroid microcarcinoma surgery.

METHODS

Carbon nanoparticles and intraoperative neuromonitoring were used in the experimental group, whereas the control group were not. Routine pathological examination was performed.

RESULTS

The lymph nodes dissected was significantly higher in the experimental group, but the metastatic lymph nodes were not. The number of mistakenly dissected parathyroid gland and postoperative hypoparathyroidism were 3 and 13 in the experimental group respectively, significantly less than 10 and 25 in the control group. The incidences of overall, transient and persistent recurrent laryngeal nerve palsy in the experimental group were 5.5%, 5.5% and 0% respectively, whereas in the control group were 8.6%, 6.9% and 1.7%.

CONCLUSIONS

Carbon nanoparticles can improve lymph node dissection in papillary thyroid microcarcinoma surgery, and the combination of carbon nanoparticles with intraoperative neuromonitoring can reduce surgical complications and improve patient quality of life.

Informed Consent for Intraoperative Neural Monitoring in Thyroid and Parathyroid Surgery - Consensus Statement of the International Neural Monitoring Study Group

In the past decade, the use of intraoperative neural monitoring (IONM) in thyroid and parathyroid surgery has been widely accepted by surgeons as a useful technology for improving laryngeal nerve identification and voice outcomes, facilitating neurophysiological research, educating and training surgeons, and reducing surgical complications and malpractice litigation. Informing patients about IONM is not only good practice and helpful in promoting the efficient use of IONM resources but is indispensable for effective shared decision making between the patient and surgeon. The International Neural Monitoring Study Group (INMSG) feels complete discussion of IONM in the preoperative planning and patient consent process is important in all patients undergoing thyroid and parathyroid surgery. The purpose of this publication is to evaluate the impact of IONM on the informed consent process before thyroid and parathyroid surgery and to review the current INMSG consensus on evidence-based consent. The objective of this consensus statement, which outlines general and specific considerations as well as recommended criteria for informed consent for the use of IONM, is to assist surgeons and patients in the processes of informed consent and shared decision making before thyroid and parathyroid surgery.

Prognostic Indicators of Non-Transection Nerve Injury and Vocal Fold Motion Impairment After Thyroid Surgery - Correlation Between Intraoperative Neuromonitoring Findings and Perioperative Voice Parameters

OBJECTIVES

In patients with recurrent laryngeal nerve (RLN) injury after thyroid surgery, unrecovered vocal fold motion (VFM) and subjective voice impairment cause extreme distress. For surgeons, treating these poor outcomes is extremely challenging. To enable early treatment of VFM impairment, this study evaluated prognostic indicators of non-transection RLN injury and VFM impairment after thyroid surgery and evaluated correlations between intraoperative neuromonitoring (IONM) findings and perioperative voice parameters.

METHODS

82 adult patients had postoperative VFM impairment after thyroidectomy were enrolled. Demographic characteristics, RLN electromyography (EMG), and RLN injury mechanism were compared. Multi-dimensional voice program, voice range profile and Index of voice and swallowing handicap of thyroidectomy (IVST) were administered during I-preoperative; II-immediate, III-short-term and IV-long-term postoperative periods. The patients were divided into R/U Group according to the VFM was recovered/unrecovered 3 months after surgery. The patients in U Group were divided into U1/U2 Group according to total IVST score change was <4 and ≥4 during period-IV.

RESULTS

Compared to R Group (42 patients), U Group (38 patients) had significantly more patients with EMG >90% decrease in the injured RLN (p<0.001) and thermal injury as the RLN injury mechanism (p=0.002). Voice parameter impairments were more severe in U Group compared to R Group. Compared to U1 group (19 patients), U2 Group (19 patients) had a significantly larger proportion of patients with EMG decrease >90% in the injured RLN (p=0.022) and thermal injury as the RLN injury mechanism (p=0.017). A large pitch range decrease in period-II was a prognostic indicator of a moderate/severe long-term postoperative subjective voice impairment.

CONCLUSION

This study is the first to evaluate correlations between IONM findings and voice outcomes in patients with VFM impairment after thyroid surgery. Thyroid surgeons should make every effort to avoid severe type RLN injury (e.g., thermal injury or injury causing EMG decrease >90%), which raises the risk of unrecovered VFM and moderate/severe long-term postoperative subjective voice impairment. Using objective voice parameters (e.g., pitch range) as prognostic indicators not only enables surgeons to earlier identify patients with low voice satisfaction after surgery, and also enable implementation of interventions sufficiently early to maintain quality of life.

Use of GlideScope in Patients Undergoing NIM Thyroidectomy

OBJECTIVES

Thyroidectomy and parathyroidectomy using the nerve integrity monitor (NIM) require proper placement of the endotracheal tube with electrodes aligned correctly within the larynx. The purpose of this study is to determine the percentage of patients who require positional adjustments of the endotracheal tube prior to beginning surgery and to understand the value of using the GlideScope to assure proper NIM tube placement within the larynx.

METHODS

This prospective study examines operative data from 297 patients who underwent NIM thyroidectomy and parathyroidectomy. After routine orotracheal intubation by an anesthesiologist and positioning of the patient for surgery, a GlideScope was used to check the position of the tube in 2 planes: depth of tube placement and rotation of the tube within the larynx assuring proper placement of the electromyogram electrodes within the glottis.

RESULTS

Tube adjustment was required for 66.5% of patients. In 48.1% of cases, tube retraction or advancement to a proper depth was needed. Tube rotation was required for 30.1% of patients, and 11.8% of patients required both adjustment of tube depth and tube rotation to properly align electrodes.

CONCLUSIONS

After the anesthesiologist places the NIM endotracheal tube, and the patient is positioned for surgery, additional tube adjustment is often needed prior to the start of surgery. The GlideScope is readily available in the operating suite, its use adds little time to the procedure, and assures proper NIM tube placement. The use of the GlideScope is recommended.

Uniqueness of laryngeal nerve injury following heart transplantation

BACKGROUND

The incidence of recurrent laryngeal nerve injury (RLNI) after heart transplantation has not been well studied. This can manifest as vocal cord dysfunction causing dysphonia. Previous research is limited to aortic, coronary bypass, and valvular surgery. Identifying RLNI after heart transplantation is important in order to more accurately detail complications associated with this major surgery.

METHODS

This is a retrospective study assessing 972 adult patients who underwent orthotopic heart transplantation between 2010-2019. Primary outcome was incidence of RLNI. Secondary outcomes were 1-year mortality and length of stay. Cardiology and otolaryngology notes were examined. Key word searches were used to identify possible RLNI in patients' health care record.

RESULTS

2.9% (29/972) of patients developed new RLNI confirmed by laryngoscopy during hospitalization. Patients with RLNI had a significantly increased risk of 1-year mortality (P = .015) and length of stay (P = .006) compared to those without RLNI. 68.9% (20/29) of RLNI was left-sided (68.9%).

CONCLUSIONS

Recurrent laryngeal nerve injury is a recognizable adverse outcome following heart transplantation. This study supports that RLNI is associated with increased 1-year mortality and length of stay. Early otolaryngology evaluation may be warranted to evaluate vocal cord mobility and address potential management.