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.

Patient Experiences With Thyroid Nodules: A Qualitative Interview Survey.

Objective: To qualitatively explore the broad set of preferences and attitudes patients have about thyroid nodules, which influence the decision-making process. Study Design: A descriptive survey design was administered as interviews. Setting: Outpatient thyroid surgery clinic. Methods: Semistructured interviews were conducted with 20 patients presenting for initial evaluation of thyroid nodules at a surgeon's office. Probative, open-ended questions were posed regarding diagnosis, treatment, risk attitudes, and the decision-making process. Thematic analysis was used to develop code-transcribed interviews, and an iterative refinement resulted in underlying themes. Results: During the diagnostic process, patients integrated emotional responses (fear, anxiety, and shock) with rationale concerns (likelihood of cancer, risk assessment), and ultimately relied heavily on expert opinion and recommendation. Contextualization with other personal or familial health problems served as helpful touchstones for decision-making. Overtreatment and overdiagnosis were not commonly discussed. When thinking about potential therapies, there was a strong bias to action rather than surveillance among patients. Surgical risk and the possibility of lifelong medication, however, were strong motivators for a subset of patients to seek nonsurgical alternatives. Conclusion: Patients describe a decision-making process that incorporates emotional response and rational consideration of risks, contextualized within the personal experience and physician expertise. The bias for action and intervention is strong, and most patients strongly weighted physicians' recommendations. Themes from this qualitative analysis may serve as the backbone for future stated preference research pertaining to thyroid disease.

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.

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.

Immunotherapy in anaplastic thyroid cancer.

Anaplastic thyroid cancer (ATC) is one of the worst human malignancies, with an associated median survival of only 5 months. It is resistant to conventional thyroid cancer therapies, including radioiodine and thyroid-stimulating hormone suppression. Cancer immunotherapy has emerged over the past few decades as a transformative approach to treating a wide variety of cancers. However, immunotherapy for ATC is still in the experimental stage. This review will cover several strategies of immunotherapy and discuss the possible application of these strategies in the treatment of ATC (such as targeted therapy for tumor-associated macrophages, cancer vaccines, adoptive immunotherapy, monoclonal antibodies and immune checkpoint blockade) with the hope of improving the prognosis of ATC in the future.