Noninvasive monitoring of the vagus nerve during thyroid surgery using cutaneous adhesive and needle electrodes: What is the optimal configuration?

OBJECTIVE: Endotracheal tube (ETT) surface electrodes are used to monitor the vagus nerve (VN), recurrent laryngeal nerve (RLN), and external branch of the superior laryngeal nerve (EBSLN) during thyroid and parathyroid surgery. Alternative nerve monitoring methods are desirable when intubation under general anesthesia is not desirable or possible. In this pilot study, we compared the performance of standard ETT electrodes to four different noninvasive cutaneous recording electrode types (two adhesive electrodes and two needle electrodes) in three different orientations. METHODS: The VN was stimulated directly during thyroid and parathyroid surgery using a Prass stimulator probe. Electromyographic (EMG) responses for each patient were recorded using an ETT plus one of the following four cutaneous electrode types: large-foot adhesive, small-foot adhesive, long-needle and short-needle. Each of the four electrode types was placed in three orientations: (1) bilateral, (2) ipsilateral mediolateral, and (3) ipsilateral craniocaudal. RESULTS: Four surgical cases were utilized for data collection with the repetitive measures obtained in each subject. Bilateral electrode orientation was superior to ipsilateral craniocaudal and ipsilateral mediolateral orientations. Regardless of electrodes type, all amplitudes in the bilateral orientation were >100 µV. When placed bilaterally, the small-foot adhesive and the long-needle electrodes obtained the highest EMG amplitudes as a percentage of ETT amplitudes. CONCLUSION: Cutaneous electrodes could potentially be used to monitor the VN during thyroid and parathyroid procedures. Different electrode types vary in their ability to record amplitudes and latencies. Bilateral orientation improves EMG responses in all electrode types. Additional validation of cutaneous electrodes as an alternative noninvasive method to monitor the VN is needed.

Surgical and Biochemical Outcomes in Nerve Monitored Reoperation Surgery for Recurrent Papillary Thyroid Carcinoma.

OBJECTIVE: To study the surgical and biochemical outcomes in nerve-monitored reoperation or revision surgery for recurrent thyroid cancers. STUDY DESIGN: A single-center retrospective study. SETTING: Tertiary center. METHODS: We identified patients with recurrent papillary thyroid carcinoma (PTC) who underwent reoperation/revision surgery. Study outcomes were surgical complications frequency, recurrence, distant metastasis, and biological complete response (BCR) by comparing preoperative and postoperative thyroglobulin (Tg) levels. RESULTS: Out of 227 patients, 33.9% presented for ≥2 reoperation surgeries. Nineteen (8.4%) had permanent preoperative hypoparathyroidism while 22 patients (9.7%) had preoperative vocal cord paralysis (VCP). Following reoperation surgery, there were 12 cases (5.3%) of permanent hypocalcemia and no cases of unexpected postoperative VCP. BCR was achieved in 31 patients (35.2%) with complete Tg data. Mean preoperative Tg was 47.7 ng/mL and was 19.7 ng/mL postoperatively (p = .003). The cervical nodal recurrence rate after final surgery was 7.0% (n = 16). CONCLUSION: Reoperation surgery for recurrent PTC may help achieve biochemical remission regardless of age or the number of prior surgeries.

Recurrent Laryngeal Nerve Invasion by Thyroid Cancer: Laryngeal Function and Survival Outcomes.

BACKGROUND: Recurrent laryngeal nerve (RLN) invasion by thyroid carcinoma represents an advanced disease status with potentially significant co-morbidity. METHODS: In a retrospective single-center study, we included patients with invaded RLNs operated on while using nerve monitoring techniques. We studied pre-, intra-, and postoperative parameters associated with postoperative vocal cord paralysis (VCP); 5-year recurrence-free survival (RFS); and 5-year overall survival (OS) in addition to two subgroup analyses of postoperative VCP in patients without preoperative VCP and based on source of RLN invasion. RESULTS: Of 65 patients with 66 nerves-at-risk, 39.3% reported preoperative voice complaints. Preoperative VCP was documented in 43.5%. The RLN was invaded by primary tumor in 59.3% and nodal metastasis in 30.5%. Papillary thyroid carcinoma was the most common pathologic subtype (80%). After 6 months, 81.8% had VCP. Complete tumor resection of the RLN was not associated with 5-year RFS (p = 0.24) or 5-year OS (p = 0.9). Resecting the RLN did not offer statistically significant benefit on 5-year RFS (p = 0.5) or 5-year OS (p = 0.38). Radioactive Iodine (RAI) administration was associated with improvement in 5-year RFS (p = 0.006) and 5-year OS (p = 0.004). Patients without preoperative VCP had higher IONM amplitude compared with patients with VCP. After a mean follow-up of 65.8 months, 35.9% of patients had distant metastases, whereas 36.4% had recurrence. CONCLUSION: Preoperative VCP accompanies less than half of patients with RLN invasion. Invaded RLNs may have existent electrophysiologic stimulability. Complete tumor resection and RLN resection were not associated with better 5-year RFS or OS, but postoperative RAI was. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:2285-2292, 2022.

How Many Nodes to Take? Lymph Node Ratio Below 1/3 Reduces Papillary Thyroid Cancer Nodal Recurrence.

INTRODUCTION: Papillary thyroid carcinoma (PTC) accounts for the majority of thyroid malignancies; risk of PTC recurrence over a 30-year period is approximately 30%, of which 70% occur as nodal metastases. Patients with nodal disease who are treated with therapeutic dissection are at higher risk for recurrence, but optimal nodal yield has not been defined. We aim to determine variables predictive of nodal recurrence of PTC within the first 5 years of surgery, with a focus on lymph node ratio (LNR), to inform clinical decision-making. METHODS: Retrospective chart review identified 41 patients with nodal recurrence of PTC and 284 without nodal recurrence following thyroid surgery from 2000 to 2015. Cohorts were compared with regards to clinical history, surgical findings, and tumor characteristics. RESULTS: The fraction of the patients who underwent therapeutic central or lateral lymph node dissection was significantly higher in the nodal recurrence cohort. Maximum tumor size, presence of extrathyroidal extension, largest lymph node focus, LNR, postoperative thyroglobulin level, and administration of postoperative radioactive iodine were significantly increased in the PTC nodal recurrence group. LNR greater than 0.3 held the highest level of significance as a binary cutoff and captured the larger proportion of patients in the nodal recurrence cohort (68.3%). CONCLUSION: This study demonstrates characteristics to help assess risk of nodal recurrence of PTC and suggests LNR of lower than 0.3 is optimal to reduce risk of recurrence. The next steps include cohort studies to validate findings and weight variable analysis to optimize the extent of surgical therapeutic dissection. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:1883-1887, 2022.

Pediatric intraoperative nerve monitoring during thyroid surgery: A review from the American Head and Neck Society Endocrine Surgery Section and the International Neural Monitoring Study Group.

Children are more likely to experience recurrent laryngeal nerve (RLN) injury during thyroid surgery. Intraoperative nerve monitoring (IONM) may assist in nerve identification and surgical decision making. A literature review of pediatric IONM was performed and used to inform a monitoring technique guide and expert opinion statements. Pediatric IONM is achieved using a variety of methods. When age-appropriate endotracheal tubes with integrated surface electrodes are not available, an alternative method should be used. Patient age and surgeon experience with laryngoscopy influence technique selection; four techniques are described in detail. Surgeons must be familiar with the nuances of monitoring technique and interpretation; opinion statements address optimizing this technology in children. Adult IONM guidelines may offer strategies for surgical decision making in children. In some cases, delay of second-sided surgery may reduce bilateral RLN injury risk.

Varied Recurrent Laryngeal Nerve Course Is Associated with Increased Risk of Nerve Dysfunction During Thyroidectomy: Results of the Surgical Anatomy of the Recurrent Laryngeal Nerve in Thyroid Surgery Study, an International Multicenter Prospective Anatomic and Electrophysiologic Study of 1000 Monitored Nerves at Risk from the International Neural Monitoring Study Group.

Background: The recurrent laryngeal nerve (RLN) can be injured during thyroid surgery, which can negatively affect a patient's quality of life. The impact of intraoperative anatomic variations of the RLN on nerve injury remains unclear. Objectives of this study were to (1) better understand the detailed surgical anatomic variability of the RLN with a worldwide perspective; (2) establish potential correlates between intraoperative RLN anatomy and electrophysiologic responses; and (3) use the information to minimize complications and assure accurate and safe intraoperative neuromonitoring (IONM). Methods: A large international registry database study with prospectively collected data was conducted through the International Neural Monitoring Study Group (INMSG) evaluating 1000 RLNs at risk during thyroid surgery using a specially designed online data repository. Monitored thyroid surgeries following standardized IONM guidelines were included. Cases with bulky lymphadenopathy, IONM failure, and failed RLN visualization were excluded. Systematic evaluation of the surgical anatomy of the RLN was performed using the International RLN Anatomic Classification System. In cases of loss of signal (LOS), the mechanism of neural injury was identified, and functional evaluation of the vocal cord was performed. Results: A total of 1000 nerves at risk (NARs) were evaluated from 574 patients undergoing thyroid surgery at 17 centers from 12 countries and 5 continents. A higher than expected percentage of nerves followed an abnormal intraoperative trajectory (23%). LOS was identified in 3.5% of NARs, with 34% of LOS nerves following an abnormal intraoperative trajectory. LOS was more likely in cases of abnormal nerve trajectory, fixed splayed or entrapped nerves (including at the ligament of Berry), extensive neural dissection, cases of cancer invasion, or when lateral lymph node dissection was needed. Traction injury was found to be the most common form of RLN injury and to be less recoverable than previous reports. Conclusions: Multicenter international studies enrolling diverse patient populations can help reshape our understanding of surgical anatomy during thyroid surgery. There can be significant variability in the anatomic and intraoperative characteristics of the RLN, which can impact the risk of neural injury.

Comparison of Monopolar and Bipolar Stimulator Probes for Intraoperative Nerve Mapping During Thyroidectomy: A Prospective Study.

OBJECTIVES/HYPOTHESIS: During intraoperative neuromonitoring in thyroid surgery, two different kinds of stimulator probes, monopolar and bipolar, are commonly used to stimulate the laryngeal nerves. We explore the unique characteristics of both of these probes as they relate to intraoperative laryngeal nerve mapping. METHODS: Twenty-one patients undergoing neuromonitored thyroidectomy by a single surgeon were enrolled. Electromyography (EMG) amplitude and latency measurements were prospectively recorded concurrently from 1 mA stimulation of vagus nerve (VN) and inferior/superior recurrent laryngeal nerve before (with and without fascia) and after thyroid resection using bipolar and monopolar stimulator probes. RESULTS: Significantly higher amplitudes were obtained with monopolar stimulator probes as compared to bipolar probes, in several stimulation scenarios such as at right VN pre-resection (carotid sheath intact), right VN pre-resection (carotid sheath dissected), right VN post-resection and left VN (carotid sheath dissected). No significant differences were found between amplitudes and latency values in all other stimulation scenarios. CONCLUSIONS: According to this study, both probes are reliable and safe for neural mapping. The kind of probe used during neural monitoring is based on surgical situations and surgeon preference. LEVEL OF EVIDENCE: 3 (According to Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence) Laryngoscope, 131:E2718-E2726, 2021.

Meta-analysis on continuous nerve monitoring in thyroidectomies.

In the last decade, the introduction of continuous intraoperative recurrent laryngeal nerve (RLN) monitoring (C-IONM) has enabled the operator to verify the functional integrity of the vagus nerve-recurrent laryngeal nerve (VN-RLN) axis in real-time. We aim to present the current evidence on C-IONM utility for thyroid surgery by conducting the first meta-analysis on this technique. A systematic review of literature was conducted by two independent reviewers via Ovid in the Medline, EMBASE, and Cochrane reviews databases. The search was limited to human subject research in peer-reviewed articles of all languages published between Jan 1946 and April 2020. Medical subject headings (MeSH) terms utilized were thyroid surgery, thyroidectomies, recurrent laryngeal nerve, vagal nerve, monitor, and stimulation. Thirty-eight papers were identified from Ovid, another six papers were identified by hand-search. A random effect meta-analysis was performed with assessment of heterogeneity using the I2 value. A total of 23 papers that investigated the use of continuous vagal nerve monitoring during thyroid surgery were identified. The proportion of nerves at risk (NAR) with temporary RLN paralysis postoperation was 2.26% (95% CI: 1.6-2.9, I2  = 37). The proportion of NAR with permanent RLN palsy postoperation was 0.05% (95% CI: 0.08-0.2, I2  = 0). In this meta-analysis, there is one case of temporary vagal nerve paralysis secondary to VN electrode dislodgement, and a case of hemodynamic instability manifested in bradycardia and hypotension in the initial phase of surgery shortly after calibration. C-IONM is a safe and effective means by which RLN paralyses in thyroid surgery can be reduced.

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.

One institution's experience with self-audit of opioid prescribing practices for common cervical procedures.

BACKGROUND: We aim to audit our institution's opioid prescribing practices after common cervical procedures. METHODS: Retrospective cohort study from one medical center. Reviewed records from 2016-2019 for 472 patients who underwent one of several common cervical procedures. Data collected on demographics, perioperative details, in-hospital pain medication use, and opioids prescribed at discharge. Multivariable logistic regression was run. RESULTS: In hospital, median daily milligram morphine equivalents (MME) was 4 (IQR 0-15). Median MME prescribed at discharge was 112.5 MME (IQR 75-150). 3/472 patients received NSAIDs. Predictors of decreased discharge MME were age 70 and older (OR 0.33, p = 0.037) and more recent year (compared to 2016, OR 0.23 [p = 0.031] for 2017, OR 0.13 [p = 0.001] for 2018, and OR 0.070 [p < 0.001] for 2019). CONCLUSIONS: MME prescribed at discharge was 28 times the daily in-hospital MME. Only 3/472 patients received postoperative NSAIDs. Self-auditing of opioid prescribing practices identifies actionable items for change.

Superior Laryngeal Nerve Signal Attenuation Influences Voice Outcomes in Thyroid Surgery.

OBJECTIVES/HYPOTHESIS: The objective was to identify whether injury of the external branch of the superior laryngeal nerve (EBSLN) or changes in EBSLN parameters after dissection during thyroidectomies correlate with changes in voice quality postoperatively. STUDY DESIGN: Prospective multicenter case series. METHODS: A prospective multicenter study was conducted on patients undergoing thyroidectomies with intraoperative nerve monitoring. Electromyography waveforms of EBSLN stimulation before (S1) and after superior pole dissection (S2) were evaluated using endotracheal tube (ETT) and cricothyroid intramuscular (CTM) electrodes. Voice outcomes were assessed using Voice-Related Quality of Life Surveys and Voice Handicap Index. RESULTS: A total of 131 at-risk EBSLNs were evaluated in 80 patients. Two nerves showed loss of CTM twitch coupled with an absent S2 signal response. Complete EBSLN loss of signal was more likely with: 1) Cernea EBSLN anatomic classification Type 2B; 2) with a longer distance from the sternothyroid muscle insertion site; and 3) with larger lobar volumes (P < .05). Patients who experienced a more than 50% decrement in CTM amplitudes of S2 (n = 7) by CTM electrodes had a statistically significant decline in their voice outcomes compared to those who did not (n = 69) (P < .05). CONCLUSIONS: Patients experienced worse voice outcomes when at least one EBSLN response amplitude decreased by more than 50% after dissection when measured by CTM needle electrodes. CTM needle electrodes have an ability to measure finer amplitude changes compared to ETT electrodes, may represent a safe method to deduce subtle EBSLN injuries, and may serve to optimize voice outcomes during thyroidectomy. CTM needle electrodes are safe and tolerated well. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:1436-1442, 2021.

Precision Neuromuscular Block Management for Neural Monitoring During Thyroid Surgery.

INTRODUCTION: Titration of neuromuscular block (NMB) plays a key role in intraoperative recurrent laryngeal nerve monitoring during thyroid surgery. The combination of neuromuscular blocking agent and timely partial reversal of NMB was investigated in both animal experiments and clinical neuro-monitored thyroidectomy. METHODS: In animal experiments, 8 piglets received sugammadex to assess the laryngeal EMG recovery after rocuronium-induced NMB. In clinical monitored thyroidectomy, 40 patients each were allocated to conventional group and sugammadex group. Conventional group received rocuronium 0.3 mg/kg at anesthesia induction, while sugammadex group received partial NMB recovery protocol- 0.6 mg/kg of rocuronium at anesthesia induction and 0.5 mg/kg of sugammadex. Main outcome was assessed by first (V1) and final (V2) EMG signal induced by vagal stimulation. RESULTS: In the porcine model, 50% recovery of laryngeal EMG amplitude was achieved at 16.8 ± 1.9 and 6 ± 2.7 minutes respectively after 0.5 and 1 mg/kg of sugammadex (p < 0.01). In monitored thyroidectomy, EMG amplitudes at V1 in group S and group C were 1214 ± 623 and 915 ± 476 µV, respectively (p = 0.02). Positive and adequately high EMG amplitudes were observed at the early surgical stage for all patients. Sugammadex groups were superior to conventional group in EMG tube placement (p < 0.001). CONCLUSION: Both porcine model and clinical application showed that precise NMB management by low-dose sugammadex was effective for intraoperative neural monitoring (IONM). The regimen ensured optimal conditions for tracheal intubation and timely neuromuscular function restoration for high-quality EMG signal.

Limitations of preoperative cytology for medullary thyroid cancer: Proposal for improved preoperative diagnosis for optimal initial medullary thyroid carcinoma specific surgery.

BACKGROUND: Preoperative diagnosis of medullary thyroid carcinoma (MTC) is often difficult, given the poor sensitivity of fine-needle aspiration (FNA) cytology for MTC. This study investigates this issue and presents recommendations for improving preoperative diagnostic paradigms in MTC cases. DESIGN/METHOD: Histopathologically confirmed MTC patients with preoperative cytologic assessment of index nodules were enrolled. FNA diagnosis, final pathology, and surgery details were collected. RESULTS: Out of 71 patients, 49 (69%) were diagnosed by FNA as either definitive MTC (35, 49%) or suspected MTC (14, 20%) and 22 (31%) patients had no indication of MTC on FNA. CONCLUSION: In a tertiary-care setting, one-third of subjects had an FNA interpretation that did not suggest the possibility of MTC. The limitations of preoperative diagnosis are especially problematic for MTC as they can cause delayed or incomplete treatment. Additional testing is proposed to improve preoperative diagnosis and surgical care of MTC patients.

Immediate Intraoperative Repair of the Recurrent Laryngeal Nerve in Thyroid Surgery.

OBJECTIVES: Recurrent laryngeal nerve (RLN) injury is a recognized risk during thyroid and parathyroid surgery and can result in significant morbidity. The aim of this review paper is to consider the optimal approach to the immediate intraoperative repair of the RLN during thyroid surgery. METHODS: A PubMed literature search was performed from inception to June 2020 using the following search strategy: immediate repair or repair recurrent laryngeal nerve, repair or reinnervation recurrent laryngeal nerve and immediate neurorraphy or neurorraphy recurrent laryngeal nerve. RESULTS: Methods of immediate intraoperative repair of the RLN include direct end-to-end anastomosis, free nerve graft anastomosis, ansa cervicalis to RLN anastomosis, vagus to RLN anastomosis, and primary interposition graft. Techniques of nerve repair include micro-suturing, use of fibrin glue, and nerve grafting. Direct micro-suture is preferable when the defect can be repaired without tension. Fibrin glue has also been proposed for nerve repair but has been criticized for its toxicity, excessive slow reabsorption, and the risk of inflammatory reaction in the peripheral tissues. When the proximal stump of the RLN cannot be used, grafting could be done using transverse cervical nerve, supraclavicular nerve, vagus nerve, or ansa cervicalis. CONCLUSIONS: Current evidence is low-level; however, it suggests that when the RLN has been severed, avulsed, or sacrificed during thyroid surgery it should be repaired intraoperatively. The immediate repair has on balance more advantages than disadvantages and should be considered whenever possible. This should enable the maintenance of vocal cord tone, better and prompter voice recovery and avoidance of aspiration. Laryngoscope, 131:1429-1435, 2021.

Modern surgery for advanced thyroid cancer: a tailored approach.

Surgical treatment of advanced thyroid malignancy can be morbid, compromising normal functions of the upper aerodigestive tract. There is a paucity of guidelines dedicated to the management of advanced disease. In fact, there is not even a uniform definition for advanced thyroid cancer currently. The presence of local invasion, bulky cervical nodes, distant metastases or recurrent disease should prompt careful preoperative evaluation and planning. Surgical strategy should evolve from multidisciplinary discussion that integrates individual disease characteristics and patient preference. Intraoperative neuromonitoring has important applications in surgery for advanced disease and should be used to guide surgical strategy and intraoperative decision-making. Recent paradigm shifts, including staged surgery and use of neoadjuvant targeted therapy hold potential for decreasing surgical morbidity and improving clinical outcomes. Modern surgical planning provides optimal treatment for each patient through a tailored approach based on exact extent and type of disease as well as incorporating appreciation of surgical complications, patient preferences and intraoperative findings.

Neuromonitored Thyroid Surgery: Optimal Stimulation Based on Intraoperative EMG Response Features.

OBJECTIVES: To evaluate/compare normative electrophysiologic electromyography (EMG) response characteristics of recurrent laryngeal, vagus, and external branch of superior laryngeal nerve evoked with different stimulators used in neuromonitored thyroid surgery. STUDY DESIGN: Prospective crossover study METHODS: EMG responses obtained via endotracheal tube surface electrodes in 11 patients undergoing thyroid surgery were recorded when stimulated with four stimulators: two monopolar (Prass standard and ball tip), one bipolar, and one dissecting instrument. Normative mean EMG results including latency, amplitude, threshold, saturation currents, and distance-sensitivity were compared. RESULTS: The Prass standard stimulator had shorter latency time when nerve was not covered with fascia (P = .04). The bipolar, dissecting instrument, and ball tip demonstrated similar latency times with and without nerve fascia. Pooled mean latency increased significantly from 1.86 ms to 2.16 ms when comparing nerves without fascia and nerves with fascia (P < .05). The Prass standard monopolar stimulator had the lowest mean threshold at 0.40 mA, with the dissecting instrument having the highest threshold at 0.89 mA for dissected nerve. Pooled mean threshold and saturation increased from 0.6 mA to 1.7 mA (P < .0001) and 1.57 mA to 4.15 mA (P < .001) with fascia covering nerve, respectively. The mean depolarization rate was 100% for monopolar and bipolar electrodes and 81% for dissecting instrument at 1 mA. Only 9% of monopolar electrodes generated an EMG response when stimulated from 2 mm away. CONCLUSION: Monopolar stimulators are more sensitive for neural mapping, whereas bipolar instruments are more specific, thus reducing false positive stimulation. Dissecting instruments share many features of monopolar stimulators while being more specific, and thus are a viable alternative. LEVEL OF EVIDENCE: 2b Laryngoscope, 2020.

The Presence of Hürthle Cells Does Not Increase the Risk of Malignancy in Most Bethesda Categories in Thyroid Fine-Needle Aspirates.

Background: Hürthle cell/oncocytic change is commonly reported on thyroid fine-needle aspiration (FNA) and may be considered an "atypical cell" by clinicians. This study aims to delineate the association between Hürthle cells in preoperative cytology and subsequent pathology of the indexed thyroid nodule and to report rates of malignancy. Methods: Retrospective review of records of 300 patients with Hürthle cell/oncocytic change on FNA and final surgical pathology at a tertiary referral center between 2000 and 2013 was performed and compared with a multi-institutional FNA cohort. The degree of Hürthle cell presence was correlated with histopathologic diagnoses. Results: In the Hürthle cell FNA group, Bethesda System for Reporting Thyroid Cytopathology (BSRTC) categories were as follows: I (nondiagnostic) 14 (4.7%); II (benign) 113 (37.7%); III (atypia of undetermined significance/follicular lesion of undetermined significance) 33 (11%); IV (follicular neoplasm/suspicious for a follicular neoplasm) 125 (41.6%); V (suspicious for malignancy) 12 (4%); and VI (malignant) 3 (1%). When categorized based on the degree of Hürthle cell change, 59 (29%) were classified as mild, 13 (6%) moderate, and 131 (65%) as predominant. When comparing the results with a multi-institutional FNA cohort (all with surgical confirmation), the presence of Hürthle cells was found to be associated with a lower risk of malignancy in all BSRTC categories, with a statistically significant difference in the BSRTC IV and V groups. The sole exception was when Hürthle cell presence was classified as predominant (defined as >75% of the cellular population); the rate of malignancy was significantly elevated in FNAs interpreted as benign/Bethesda II. Conclusions: Although Hürthle cells have been considered by clinicians as an "atypical cell," their presence does not increase the risk of malignancy within BSRTC categories overall. However, when predominant Hürthle cell change is present, the risk of malignancy is increased in the benign cytology/BSRTC category II.

Increased prevalence of neural monitoring during thyroidectomy: Global surgical survey.

OBJECTIVE: To investigate intraoperative nerve monitoring (IONM) use among thyroid surgeons. METHODS: A 25-question survey was used to assess attitudes regarding IONM use. Surveys were sent to surgeons registered to the American Academy of Otolaryngology-Head and Neck Surgery, International Association of Endocrine Surgeons, and American Head and Neck Society. RESULTS: Among 1,015 respondents, 83% reported using IONM (65.1% always using IONM and 18.1% reporting selective use). For selective users, a majority reported using IONM for reoperative cases (95.1%) and in cases with preoperative vocal cord paralysis (59.8%). When comparing location, there was a significant difference in IONM implementation (P < 0.001), with 70.4% of North American responders using it ubiquitously compared to 27.4% of non-North American responders. Preoperative laryngeal exam was performed more universally by North American surgeons and more selectively by non-North American surgeons (P < 0.001). Other attitudes toward their implementation and the postoperative laryngeal exam were similar. Surgeons ≤45 years of age and those with ≤15 years of practice used IONM more than their peers (P < 0.001). Thyroid surgery volume, fellowship training, and type of practice had no bearing on IONM use. CONCLUSION: The prevalence of IONM in thyroid and parathyroid surgeries has increased significantly over the past decade, with 83% of surgeons using IONM in some or all cases. Although IONM use may be more ubiquitous in North America, attitudes toward its implementation and pre- and postoperative laryngeal exams are fairly uniform. IONM use is more prevalent among younger surgeons, whereas its use has no correlation with thyroid surgery volume or type of practice. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1097-1104, 2020.

Safety and reliability of a handheld stimulator for neural monitoring during thyroid surgery.

OBJECTIVE: The Checkpoint nerve stimulator (Checkpoint Surgical, Cleveland, OH) is a U.S. Food and Drug Administration-approved device for neural localization and monitoring during surgery. Its safety, efficacy, and reliability for neural monitoring during thyroid and parathyroid surgery have not been compared to more standard formats of neural monitoring. STUDY DESIGN: Retrospective review. METHODS: Vagal, recurrent, and superior laryngeal nerve monitoring were performed using both the Checkpoint stimulator and Medtronic NIM 3.0 laryngeal electromyography endotracheal tube (Medtronic, Jacksonville, FL) during thyroid and parathyroid surgery. A total of 21 operated sides in 15 patients were included for analysis. Latency and amplitude data for the Checkpoint stimulator were recorded using the NIM monitor and compared to normative endotracheal tube surface electrode data. RESULTS: Mean amplitude using the Checkpoint stimulator was 574.6 microvolts (µV), 1060.6 µV, and 182.8 µV for the vagus, recurrent laryngeal, and superior laryngeal nerves, respectively. Mean amplitude using standard laryngeal electromyography was 709 µV, 1077.0 µV, and 183.7 µV for the same nerves. Mean latency was significantly shorter with stimulation of the recurrent laryngeal nerve compared to the vagus nerve with both stimulators (P < 0.001). No neural injuries occurred during the study. CONCLUSION: The Checkpoint stimulator is a safe and reliable alternative to traditional laryngeal electromyography providing equivalent induced electromyography of the vocalis for neural monitoring during thyroid and parathyroid surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:561-565, 2020.

Surgical management of the compromised recurrent laryngeal nerve in thyroid cancer.

Surgical management of thyroid cancer requires careful consideration of the recurrent laryngeal nerve and its impact on glottic function. Management of the compromised recurrent laryngeal nerve is a complex task, requiring synthesis of multiple elements. The surgeon must have an appreciation for preoperative recurrent laryngeal nerve function, intraoperative anatomic and electromyographic information, disease characteristics, and relevant patient factors. Preoperative clinical evaluation including preoperative laryngoscopy and assessment of recurrent laryngeal nerve risk is essential to formulating a surgical plan and providing appropriate patient counseling. Intraoperative neuromonitoring information has significant implications for surgical management of the injured or invaded recurrent laryngeal nerve and informs strategy with respect to staging of bilateral surgery. Disease characteristics and patient-related factors, including patient preference, must be considered with intraoperative decision-making. Multidisciplinary discussion and patient communication are essential for effective management and successful surgical outcome.