Surgical management of airway dysfunction in Parkinson's disease compared with Parkinson-plus syndromes.

OBJECTIVES: We sought to compare the laryngeal symptoms of Parkinson's disease (PD) with those of multiple system atrophy (MSA), a Parkinson-plus syndrome; to review the differences in surgical management of upper airway dysfunction between patients with PD and those with MSA; and to present a treatment algorithm for management of upper airway disorders in patients with PD and MSA. METHODS: We analyzed the airway manifestations of each disease, including clinical and physiological test results and management outcomes, in a case series of 30 patients (24 with PD and 6 with MSA). RESULTS: Vocal fold atrophy causing bowing with a midfold glottic gap was common in patients with PD. One third of patients with PD underwent vocal fold augmentation with noticeable improvement in vocal volume and phonation time. Tracheostomy was required for life-threatening sleep apnea in 50% of the patients with MSA. Systemic medications and speech therapy were integral components of the management regimen. CONCLUSIONS: Surgical management of laryngeal disorders in patients with PD should focus on restoring bulk to atrophic vocal folds to minimize glottic gaps, thus improving vocalization efficiency even in the presence of impaired respiratory effort. Conversely, the autonomic dysfunction that characterizes MSA results in upper airway obstruction, and thus surgical management focuses primarily on maintaining an adequate airway, which frequently necessitates tracheostomy.

Radiofrequency Ablation for Benign Thyroid Nodules.

CONTEXT: Thermal ablative techniques of the thyroid have recently gained clinical traction as a therapeutic alternative that provides symptomatic relief and confers potential advantages over surgery. A truly multidisciplinary technique, thyroid ablation is currently performed by endocrinologists, interventional radiologists, otolaryngologists, and endocrine surgeons. Radiofrequency ablation (RFA), specifically, has seen widespread adoption, particularly in the treatment of benign thyroid nodules. This review summarizes current evidence on the application of RFA in benign thyroid nodules, and provides a start to finish overview of procedural preparation, performance, and outcomes. EVIDENCE ACQUISITION: A narrative review of literature focusing on RFA in the treatment of benign nodular disease was performed. Emphasis was placed on consensus statements, best practice guidelines, multi-institutional studies, and systematic reviews to summarize key concepts in candidacy, techniques, expectations, and outcomes. FINDINGS: RFA is increasingly recognized as a first-line treatment strategy in the management of symptomatic nonfunctional benign thyroid nodules. It can also be considered in functional thyroid nodules with small volumes or in patients ineligible for surgery. A targeted and efficacious technique, RFA results in gradual volume reduction that preserves the function of the surrounding thyroid parenchyma. Proper procedural technique, proficiency in ultrasound, and experience in ultrasound-guided procedures are instrumental to maintaining low complication rates and achieving successful ablation outcomes. CONCLUSIONS: In pursuit of a personalized approach, physicians across disciplines are increasingly incorporating RFA into their treatment algorithms, most commonly for benign nodules. As with any intervention, thoughtful selection and implementation ensure a safe procedure with optimal patient benefit.

General Principles for the Safe Performance, Training, and Adoption of Ablation Techniques for Benign Thyroid Nodules: An American Thyroid Association Statement.

Background: The primary goal of this interdisciplinary consensus statement is to provide a framework for the safe adoption and implementation of ablation technologies for benign thyroid nodules. Summary: This consensus statement is organized around three key themes: (1) safety of ablation techniques and their implementation, (2) optimal skillset criteria for proceduralists performing ablative procedures, and (3) defining expectations of success for this treatment option given its unique risks and benefits. Ablation safety considerations in pre-procedural, peri-procedural, and post-procedural settings are discussed, including clinical factors related to patient selection and counseling, anesthetic and technical considerations to optimize patient safety, peri-procedural risk mitigation strategies, post-procedural complication management, and safe follow-up practices. Prior training, knowledge, and steps that should be considered by any physician who desires to incorporate thyroid nodule ablation into their practice are defined and discussed. Examples of successful clinical practice implementation models of this emerging technology are provided. Conclusions: Thyroid ablative procedures provide valid alternative treatment strategies to conventional surgical management for a subset of patients with symptomatic benign thyroid nodules. Careful patient and nodule selection are critical to the success of these procedures as is extensive pre-procedural patient counseling. Although these emerging technologies hold great promise, they are not without risk and require the development of a unique skillset and environment for optimal, safe performance and consistent outcomes.

Assessment of donor site morbidity for free radial forearm osteocutaneous flaps.

PURPOSE: Assessment of donor site morbidity and recipient site complications following free radial forearm osteocutaneous flap (FRFOCF) harvest and evaluation of patient perceived upper limb disability for free radial forearm osteocutaneous versus fasciocutaneous flaps (FRFF). METHODS: First a case series was undertaken of 218 patients who underwent an FRFOCF at two tertiary referral centers between February 1998 and November 2010. Outcomes included forearm donor site morbidity and recipient site complications. Second, the disability of the arm, shoulder, and hand (DASH) questionnaire assessing patient perceived arm disability was administered by phone to 60 consecutive patients who underwent an FRFOCF or FRFF. RESULTS: Mean patient age was 63 years with male predominance (62.8%). Median bone length harvested was 8 cm (range, 3-12 cm) with prophylactic plating of the radius following harvest. Donor site morbidity included fracture (1 patient, 0.5%) and sensory neuropathy (5 patients, 2.3%). Mean DASH scores were comparative between groups and to established normative values. Mandibular malunion rate was 3.2% and hardware extrusion at the recipient site occurred in 15.6%. CONCLUSION: Reluctance to perform FRFOCF by surgeons usually centers on concerns regarding potential donor site morbidity and adequacy of available bone stock; however, we identified minimal objective or patient perceived donor site morbidity or recipient site complications following harvest of FRFOCFs. Mild wrist weakness and stiffness are common but do not impede ability to perform activities of daily living. Data from this and other reports suggest this flap is particularly useful for midfacial and short segment mandibular reconstruction.

Radiofrequency ablation (RFA) compared to observation for benign thyroid nodules: emerging considerations for judicious use.

PURPOSE OF REVIEW: Radiofrequency ablation (RFA) for thyroid nodules confers tangible advantages over surgery, which include promising outcomes in the context of a minimally invasive procedure and the functional benefits of organ preservation. However, the ubiquity of benign nodules worldwide may spur the risk of misuse in cases where there is negligible gain over conventional surveillance. This review summarizes new developments in RFA and examines its judicious utilization in benign nodules. RECENT FINDINGS: RFA appears to be safe and effective for addressing compressive or cosmetic issues caused by benign functional and nonfunctional thyroid nodules. Volume regression occurs over 12 months, with some cases requiring multiple staged RFA procedures to achieve adequate shrinkage or to address regrowth. Complication rates including recurrent laryngeal nerve injury are reportedly low and are mitigated by strategic technical maneuvers, training, and experience. Consensus guidelines across international societies have emerged to better define appropriate patient candidates. Although association of overuse in analogous disciplines has been well established, no evidence of misuse in thyroid RFA has been described thus far. SUMMARY: Compelling multi-institutional data support RFA as first-line treatment for select benign thyroid nodules. Defining the nuances of patient selection and long-term surveillance are necessary to substantiate current observed results. Given the high incidence of thyroid nodules worldwide, it is important to emphasize that the majority of benign nodules will not require any intervention. Thorough consideration and careful implementation of recommended guidelines will hopefully lead to measurable benefit and avoid financial misuse.

Continuous intraoperative neuromonitoring of the recurrent laryngeal nerve by eliciting the laryngeal adductor reflex (LAR-CIONM).

The laryngeal adductor reflex (LAR) is a life-sustaining airway protective mechanism that serves to shield the lower airways from inhaled foreign bodies. Over the past half century, the LAR has been extensively investigated and its dysfunction has been linked to far-ranging pathologies, from dysphagia to sudden infant death syndrome. Over the past 6 years, specific electromyographic waves in the LAR response have been used to devise a methodology for monitoring the vagus and recurrently laryngeal nerves during surgical procedures. This methodology involves continuous intraoperative neuromonitoring of the laryngeal adductor reflex and isthus termed 'LAR-CIONM'. In this review paper, the physiology of the LAR will be summarized as it relates to LAR-CIONM and the technique of LAR-CIONM will be described. Applications of this technique and published outcomes of LAR-CIONM will be highlighted.

A comprehensive review of interventional ablation techniques for the management of thyroid nodules and metastatic lymph nodes.

Thyroidectomy remains the gold standard treatment for benign, symptomatic, or enlarging thyroid nodules, malignant nodules, and metastatic lymph node disease. However, in the past 2 decades, image-guided interventional techniques have emerged as promising alternative treatments for these conditions. Percutaneous ethanol ablation is now an accepted first-line treatment for recurring cystic thyroid nodules. Thermal ablation techniques such as high-intensity focused ultrasound, laser ablation, radiofrequency ablation, and microwave ablation have shown efficacy in producing a nodular volume reduction of greater than 50% that is maintained for several years with resolution of local compressive symptoms. There is also increasing evidence that these techniques can effectively treat papillary thyroid microcarcinomas and recurrent metastatic lymph node disease. Because these interventional ablation techniques are performed safely in an outpatient setting, are well tolerated, and the risk for needing thyroid hormone supplementation is negligible, they are becoming a popular alternative treatment to surgical resection. In this comprehensive review, we discuss each of these percutaneous interventions: the devices and techniques, the advantages and disadvantages of each energy, and summarize the outcomes published in the literature.

Clarifying optimal outcome measures in intermittent and continuous laryngeal neuromonitoring.

BACKGROUND: Intraoperative neuromonitoring (IONM) techniques have evolved over the past decade into intermittent IONM (I-IONM) and continuous IONM (C-IONM) modes of application. Despite many prior publications on both types of IONM, there remains uncertainty about what outcomes should be measured for each form of IONM. The primary objective of this paper is to define categories of benefit for I-IONM/C-IONM and to clarify and standardize their reporting outcomes. METHODS: Expert review consensus statement utilizing modified Delphi methodology. RESULTS: I-IONM provides diagnosis, classification, and prevention of nerve injury through accurate and early nerve identification. C-IONM provides real-time information on nerve functional integrity and thus may prevent some types of nerve injury but cannot assist in nerve localization. Sudden mechanisms of nerve injury cannot be predicted or prevented by either technique. CONCLUSIONS: I-IONM and C-IONM are complementary techniques. Future studies evaluating the utility of IONM should focus on outcomes that are appropriate to the type of IONM being utilized.

Continuous Laryngeal Adductor Reflex Versus Intermittent Nerve Monitoring in Neck Endocrine Surgery.

OBJECTIVE: Intraoperative neuromonitoring (IONM) techniques aim to identify and potentially prevent nerve injury during surgeries. Prior studies into the efficacy of recurrent laryngeal nerve (RLN) IONM convey mixed results, with some claiming equivalence between IONM and no monitoring at all. The goal of the current study was to compare continuous RLN monitoring using the laryngeal adductor reflex (LAR) to intermittent RLN monitoring (intermittent IONM) to determine whether continuous monitoring reduces the incidence of intraoperative RLN injury during neck endocrine surgeries. METHODS: In this observational, historical case-control study, a historical cohort of patients monitored with intermittent-IONM (group 1, n = 130) were compared to prospectively collected data from consecutive nerves-at-risk monitored continuously with the LAR (LAR-CIONM, group 2, n = 205), at a single center by a single surgeon. The test benefit ratio and relative risk reduction (RRR) for LAR-CIONM over intermittent IONM were calculated. RESULTS: For group 1, nine nerves at risk exhibited intraoperative LOS with transient postoperative vocal fold (VF) hypomobility (n = 2) or immobility (VFI, n = 7). For group 2, two nerves at risk (0.98%) had sudden intraoperative LAR LOS following bipolar cautery, resulting in postoperative transient VFI (P = .004). In each group, there was one case of permanent postoperative VFI. The test benefit rate ratio for LAR-CIONM demonstrated a dramatic effect at 5.23, with an RRR of 81.0%. CONCLUSION: LAR-CIONM significantly decreased rates of postoperative transient VF paralysis and paresis over intermittent IONM alone (P = .004). Surgeons should be aware of the benefits and limitations of intermittent IONM versus CIONM. Intermittent IONM, although useful in nerve mapping and intraoperative decision making, has minimal benefit for the prevention of nerve injury, whereas CIONM can potentially reduce nerve injury rates and improve patient outcomes. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:230-236, 2021.

Continuous neuromonitoring during radiofrequency ablation of benign thyroid nodules provides objective evidence of laryngeal nerve safety.

INTRODUCTION: The recurrent laryngeal nerves(RLN) run immediately posterior to the thyroid capsule and could be injured during thyroid radiofrequency ablation(RFA). This study assesses whether RLN functional integrity is altered during RFA using continuous intraoperative neuromonitoring(CIONM). METHODS: Prospective case series of twenty nodules treated with RFA under general anesthesia utilizing the laryngeal adductor reflex(LAR) for CIONM. RESULTS: Thirteen nodules abutted the posterior thyroid capsule and 'danger triangle' for RLN injury. The ablative field did not breach the posterior capsule; 40 W was the maximal power used adjacent to the capsule. No patient experienced significant LAR amplitude alterations. Pre and postoperative laryngoscopy and voice assessments were comparable. At 12 months' median follow-up, no patient displayed posterior nodule regrowth. CONCLUSIONS: This prospective case series supports the premise that benign nodule RFA is safe with regards to RLN functional integrity provided the posterior capsule is not breached by the ablation zone and posterior power is ≤ 40 W.

The short-latency R1 response of the electrical laryngeal adductor reflex contributes to airway protection by initiating glottic closure.

OBJECTIVE: The fundamental role of the short-latency (R1) laryngeal adductor reflex (LAR) response remains unclear with conflicting reports in the literature. This study's primary aim was to objectively determine whether the bilateral R1 response, which was elicited by electrical stimulation of the supraglottic mucosa, triggered bilateral glottis closure. METHODS: Video recording of the LAR in a prospective case series of patients undergoing trans-oral rigid laryngoscopy. The LAR was elicited by electrical stimulation of supraglottic mucosa. The LAR R1 and long-latency (R2) responses in laryngeal adductor musculature were correlated with mechanical vocal fold (VF) adduction in a time-locked manner. A high-speed camera recording 1057 frames per second was used to determine where in the LAR contractile closure the electrical R1 component occurred. RESULTS: Five patients were prospectively enrolled. The R1 response was present in all trials for all patients. The R2 response was recorded in four patients (80%). As assessed by the latency of the R1 response, electrical activation of the adductor muscles always preceded the mechanical onset of VF movement. VF adduction began near the middle of the R1 response in all trials for all patients. The R2 response of the LAR began after visible VF adduction for all patients. CONCLUSIONS: This study provides the first objective evidence that the bilateral R1 response of the electrically elicited LAR is the electrical event that initiates reflex airway closure. SIGNIFICANCE: These results suggest that under total intravenous anesthesia, the larynx preserves its capacity to elicit a LAR, thereby maintaining some protective functions that can prevent airway penetration.

Bleomycin sclerotherapy following doxycycline lavage in the treatment of ranulas: A retrospective analysis and review of the literature.

OBJECTIVE: A ranula is a mucus-filled salivary pseudocyst that forms in the floor of the mouth, commonly arising from the sublingual or submandibular salivary glands following obstruction or trauma. Complete excision of the injured gland and removal of the cyst content is the first-choice therapy, but has the potential for complications related to injury to nearby structures. As such, minimally invasive approaches such as percutaneous sclerotherapy have been investigated. We aim to contribute to the literature by assessing the efficacy and safety of our technique through our experience with 18 patients over the last decade. METHODS: This retrospective study evaluated 18 patients with intraoral and plunging ranulas treated by percutaneous bleomycin ablation. The primary endpoint was the treatment result. Secondary endpoints included bleomycin dosage and complications. RESULTS: The study evaluated 12 males and six females with a median age of 23.5 years (range 13-39 years). At a final follow-up of at least 2 months (6.5±5.5 months), four patients demonstrated complete response (22%) and 14 patients demonstrated residual presence, recurrence, or regrowth of the lesion (78%). There were no statistically significant associations between outcomes and history of prior treatment, number of treatments, and size or type of ranula. No complications were noted. CONCLUSIONS: Our findings indicate that bleomycin, while safe for use in various head and neck malformations, is of limited utility in ranula therapy when the offending gland is not addressed primarily.

Perioperative pain management and opioid-reduction in head and neck endocrine surgery: An American Head and Neck Society Endocrine Surgery Section consensus statement.

BACKGROUND: This American Head and Neck Society (AHNS) consensus statement focuses on evidence-based comprehensive pain management practices for thyroid and parathyroid surgery. Overutilization of opioids for postoperative pain management is a major contributing factor to the opioid addiction epidemic however evidence-based guidelines for pain management after routine head and neck endocrine procedures are lacking. METHODS: An expert panel was convened from the membership of the AHNS, its Endocrine Surgical Section, and ThyCa. An extensive literature review was performed, and recommendations addressing several pain management subtopics were constructed based on best available evidence. A modified Delphi survey was then utilized to evaluate group consensus of these statements. CONCLUSIONS: This expert consensus provides evidence-based recommendations for effective postoperative pain management following head and neck endocrine procedures with a focus on limiting unnecessary use of opioid analgesics.

Laryngeal adductor reflex hyperexcitability may predict permanent vocal fold paralysis.

Laryngeal adductor reflex-continuous intraoperative neuromonitoring (LAR-CIONM) is a novel method of continuous intraoperative neuromonitoring. In contrast to other vagal nerve monitoring techniques, which elicit a laryngeal compound muscle action potential, LAR-CIONM elicits a laryngeal reflex response (LAR). In 300 nerves at risk monitored with LAR-CIONM, two patients have had postoperative permanent vocal fold immobility (VFI). Both patients exhibited a significant LAR amplitude increase prior to complete loss of signal. No other patients have exhibited LAR hyperexcitability. If confirmed in a larger sample, this represents the first time that a vagal intraoperative neuromonitoring technique can distinguish transient from permanent VFI, which could improve patient outcomes. Laryngoscope, 2019 Laryngoscope, 130:E625-E627, 2020.

Outcomes of Patients With Hypothyroidism and COVID-19: A Retrospective Cohort Study.

Coronavirus diseases (COVID-19) is associated with high rates of morbidity and mortality and worse outcomes have been reported for various morbidities. The impact of pre-existing hypothyroidism on COVID-19 outcomes remains unknown. The aim of the present study was to identify a possible association between hypothyroidism and outcomes related to COVID-19 including hospitalization, need for mechanical ventilation, and all-cause mortality. All patients with a laboratory confirmed COVID-19 diagnosis in March 2020 in a large New York City health system were reviewed. Of the 3703 COVID-19 positive patients included in present study, 251 patients (6.8%) had pre-existing hypothyroidism and received thyroid hormone therapy. Hypothyroidism was not associated with increased risk of hospitalization [Adjusted Odds Ratio (ORadj): 1.23 (95% Confidence Interval (CI): 0.88- 1.70)], mechanical ventilation [ORadj: 1.17 (95% CI: 0.81-1.69)] nor death [ORadj: 1.07 (95% CI: 0.75-1.54)]. This study provides insight into the role of hypothyroidism on the outcomes of COVID-19 positive patients, indicating that no additional precautions or consultations are needed. However, future research into the potential complications of COVID-19 on the thyroid gland and function is warranted.

Immediate and partial neural dysfunction after thyroid and parathyroid surgery: Need for recognition, laryngeal exam, and early treatment.

BACKGROUND: Laryngeal dysfunction after thyroid and parathyroid surgery requires early recognition and a standardized approach for patients that present with voice, swallowing, and breathing issues. The Endocrine Committee of the American Head and Neck Society (AHNS) convened a panel to define the terms "immediate vocal fold paralysis" and "partial neural dysfunction" and to provide clinical consensus statements based on review of the literature, integrated with expert opinion of the group. METHODS: A multidisciplinary expert panel constructed the manuscript and recommendations for laryngeal dysfunction after thyroid and parathyroid surgery. A meta-analysis was performed using the literature and published guidelines. Consensus was achieved using polling and a modified Delphi approach. RESULTS: Twenty-two panelists achieved consensus on five statements regarding the role of early identification and standardization of evaluation for patients with "immediate vocal fold paralysis" and "partial neural dysfunction" after thyroid and parathyroid surgery. CONCLUSION: After endorsement by the AHNS Endocrine Section and Quality of Care Committee, it received final approval from the AHNS Council.

Assessment of Gender Differences in Perceptions of Work-Life Integration Among Head and Neck Surgeons.

IMPORTANCE: The factors that contribute to gender discrepancies among attending head and neck surgeons have yet to be fully characterized. OBJECTIVE: To evaluate the association of gender difference with the perceived quality of life of head and neck oncological surgeons. DESIGN, SETTING, AND PARTICIPANTS: Following approval from the American Head and Neck Society (AHNS) review board, a web-based survey study of 37 questions, mainly assessing daily lifestyle and quality of life, was sent to the entire membership. MAIN OUTCOMES AND MEASURES: The main outcome assessed was perceived quality of life among female and male surgeons. RESULTS: A total of 261 members (13.0%) responded, 71 women (27.2%) and 190 men (72.8%). In all, 66 female (92.5%) and 152 male (80%) surgeons worked at an academic institution. A greater percentage of women were at the associate professor level than men (20/64 [31%] vs 37/152 [24%]; difference, 6.9%; 95% CI, -5.6% to 20.5%) and a greater percentage of men were at the professor level than women (72/152 [47%] vs 18/64 [28%]; difference, 19%; 95% CI, 4.9% to 31.6%). This discrepancy was evident in administrative roles as well, with 4 female (6.2%) vs 23 male (17.6%) department chairs (difference, 11.3%; 95% CI, 0.9%-19.6%). Of the 71 women, 18 (25%) were not in a long-term relationship or were divorced, as opposed to 6 (3.2%) men (difference, 22%; 95% CI, 12.8%-33.5%). Women had a mean (median) 1.18 (1) children, whereas men had 2.29 (2) children. Mean age that participating women had their first child was 35.1 years, whereas the man age for men was 31.9 years. Overall, 117 men (61.9%) and 45 women (67.2%) found their family time limited compared with other otolaryngological subspecialties. Despite these results, 101 men (53.4%) vs 37 women (55.2%) stated that they had a good work-life balance. Six women vs 8 men indicated they would choose a different subspecialty if they could. CONCLUSIONS AND RELEVANCE: Despite improvements in work hours and gender balance in residency programs, discrepancy in the number of female surgeons with senior academic rankings continues. However, female and male head and neck surgeons appear equally content with their subspecialty choice.

Continuous Vagal Neuromonitoring Using the Laryngeal Adductor Reflex: Can Preincision Dyssynchrony Predict Intraoperative Nerve Behavior?

OBJECTIVE: The laryngeal adductor reflex (LAR) is an airway-protective response triggered by sensory laryngeal receptors and resulting in bilateral vocal fold adduction. The normal morphology of the early R1 response resembles that of the compound muscle action potential (CMAP). However, in a small subset of patients, the morphology is dyssynchronous with multiple peaks. This study investigates whether preoperative LAR dyssynchrony predicts intraoperative nerve behavior during thyroid surgeries. STUDY DESIGN: Retrospective case-control study. SETTING: US academic health center. SUBJECTS AND METHODS: Opening and closing LAR waveforms from 200 patients with normal preoperative laryngeal examinations monitored continuously during thyroid surgeries using the LAR were analyzed. Area under the curve (AUC) and number of "events" during surgery (defined as any transient decline in AUC >50% baseline) were determined for patients who demonstrated opening dyssynchronous LAR traces compared to demographically matched controls. RESULTS: Six patients had opening dyssynchronous LAR traces. These patients had significantly greater declines in R1 AUC than demographically matched patients with opening synchronized R1 traces (P = .007). Upon thyroid removal, 1 patient converted from a dyssynchronous to synchronous trace. CONCLUSIONS: Preincision dyssynchronous LAR waveforms may indicate subclinical, potentially reversible, neuropathy of the recurrent laryngeal nerve (RLN) and predict intraoperative RLN behavior. Preincision knowledge of R1 dyssynchrony can facilitate surgical planning as such patients may glean particular benefit from continuous intraoperative nerve monitoring, frequent tissue relaxation, and saline irrigation as means to minimize nerve stress intraoperatively.

Intraoperative mapping and monitoring of sensory vagal fibers during vagal schwannoma resection.

Vagal schwannomas are rare, benign tumors. Intermittent intraoperative neuromonitoring via selective stimulation of splayed motor fibers running on the schwannoma surface to elicit a compound muscle action potential has been previously reported as a method of preserving vagal motor fibers. In this case report, vagal sensory fibers are mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes. Laryngoscope, 129:E434-E436, 2019.

Human laryngeal sensory receptor mapping illuminates the mechanisms of laryngeal adductor reflex control.

OBJECTIVE: The laryngeal adductor reflex (LAR) is an airway protective response triggered by sensory laryngeal receptors. It is unknown whether different glottic and supraglottic subsites vary in their reflex elicitation abilities. The recent discovery that a bilateral LAR is present in humans under general anesthesia upon laryngeal mucosal stimulation has enabled us to map the sensory receptor density for LAR elicitation at different laryngeal subsites. Our findings expose the likely mechanisms of LAR control. METHODS: Prospective series of 10 patients undergoing laryngoscopy. Laryngeal subsites (epiglottic tip, membranous vocal fold, midventricular vocal fold, posterior supraglottis, epiglottic petiole) were stimulated via direct laryngoscopy with a bipolar probe. Vocal fold responses were recorded by endotracheal tube and hook wire electrodes, and visual observation. RESULTS: Posterior supraglottic stimulation elicited bilateral LARs in all patients at all intensities. Membranous vocal folds, epiglottic petiole, and subglottis elicited no LAR. Ventricular fold and epiglottic tip responses converted from ipsi- to bilateral at high intensities. CONCLUSION: There are likely three checkpoints for control of the LAR in humans. These checkpoints protect against inappropriate LAR activation during volitional tasks without compromising airway protection: 1) topographical differences in receptor density with the highest density in subsites most likely to contact foreign substances; 2) absence of receptors in membranous vocal folds; and 3) central summation threshold for crossed interneuron activation at brainstem level where only strong intensity stimuli will elicit bilateral responses. Checkpoint dysfunction provides a novel framework to diagnose and treat disease processes, including aspiration, laryngospasm, and sudden infant death. LEVEL OF EVIDENCE: 4. Laryngoscope, E365-E370, 2018.