Etiology and Time to Presentation of Unilateral Vocal Fold Paralysis

Identifying bias in models that detect vocal fold paralysis from audio recordings using explainable machine learning and clinician ratings

Detecting voice disorders from voice recordings could allow for frequent, remote, and low-cost screening before costly clinical visits and a more invasive laryngoscopy examination. Our goals were to detect unilateral vocal fold paralysis (UVFP) from voice recordings using machine learning, to identify which acoustic variables were important for prediction to increase trust, and to determine model performance relative to clinician performance. Patients with confirmed UVFP through endoscopic examination (N = 77) and controls with normal voices matched for age and sex (N = 77) were included. Voice samples were elicited by reading the Rainbow Passage and sustaining phonation of the vowel "a". Four machine learning models of differing complexity were used. SHapley Additive exPlanations (SHAP) was used to identify important features. The highest median bootstrapped ROC AUC score was 0.87 and beat clinician's performance (range: 0.74-0.81) based on the recordings. Recording durations were different between UVFP recordings and controls due to how that data was originally processed when storing, which we can show can classify both groups. And counterintuitively, many UVFP recordings had higher intensity than controls, when UVFP patients tend to have weaker voices, revealing a dataset-specific bias which we mitigate in an additional analysis. We demonstrate that recording biases in audio duration and intensity created dataset-specific differences between patients and controls, which models used to improve classification. Furthermore, clinician's ratings provide further evidence that patients were over-projecting their voices and being recorded at a higher amplitude signal than controls. Interestingly, after matching audio duration and removing variables associated with intensity in order to mitigate the biases, the models were able to achieve a similar high performance. We provide a set of recommendations to avoid bias when building and evaluating machine learning models for screening in laryngology.

Improvement in swallowing safety after injection laryngoplasty in patients with unilateral vocal paralysis complicated with aspiration

BACKGROUND

The benefit of injection laryngoplasty (IL) on voice for unilateral vocal fold paralysis (UVFP) is supported increasingly in literatures, yet less is known for swallowing. Also, prevalence of patient-reported dysphagia is substantially higher than instrumental studies. This prospective study focused on swallowing outcomes, with predetermined flexible endoscopic evaluation of swallowing (FEES) protocol that simulates daily life situation.

METHODS

Adult patients with UVFP and aspiration receiving IL were recruited. Voice outcome measurements, as well as swallowing outcomes including Eating Assessment Tool (EAT-10) and FEES, which challenged patients with different fluid volumes: 10 mL, 20 mL, and 90 mL cup sipping were evaluated.

RESULTS

Significant improvements were demonstrated in all voice outcomes. Significant changes were also presented inEAT-10 (P < 0.01). Pre-operatively, penetration-aspiration scale (PAS) was 1.5 ± 1.3, 1.9 ± 1.7 and 2.3 ± 1.8 for 10 mL, 20 mL and 90 mL serial sipping, and improved to 1.1 ± 0.3, 1.1 ± 0.4 and 1.4 ± 0.7 post-operatively (P < 0.01). Safe swallowing (PAS ≤ 2) was achieved in all, except for one patient, who presented with a post-injection PAS of 4 (material enters the airway, contacts the vocal folds, and is ejected from the airway) on 90 mL cup sipping, whose pre-injection PAS was 7 (residue in trachea).

CONCLUSION

Maintaining swallowing function suitable for social environment is important. Our results demonstrated the feasibility of the predetermined FEES protocol, and positive effects of IL on both voice and swallowing outcomes.

Immediate effect of recurrent laryngeal nerve stimulation in patients with idiopathic unilateral vocal fold paralysis

BACKGROUND

There is a lack of effective treatment for idiopathic unilateral vocal fold paralysis (IUVFP). A better phonation was reported by patients after laryngeal nerve stimulation during our clinical examination.

OBJECTIVES

This study aims to investigate immediate effect of recurrent laryngeal nerve (RLN) stimulation on phonation in patients with IUVFP.

MATERIAL AND METHODS

Sixty-two patients with clinically identified IUVFP underwent RLN stimulation with needle electrodes. Laryngoscopy, acoustic analysis, and voice perception assessment were performed for quantitative comparison of vocal function and voice quality before and after the intervention.

RESULTS

Laryngoscopic images showed a larger motion range of the paralyzed vocal fold (p < .01) and better glottal closure (p < .01) after RLN stimulation. Acoustic analysis revealed that the dysphonia severity index increased significantly (p < .01) while the jitter and shimmer decreased after the intervention (p < .05). According to perceptual evaluation, RLN stimulation significantly increased RBH grades in patients with IUVFP (p < .01). Furthermore, the improvement in voice perception had a moderate positive correlation with the decrease in the glottal closure.

CONCLUSIONS AND SIGNIFICANCE

This study shows a short-term improvement of phonation in IUVFP patients after RLN stimulation, which provides proof-of-concept for trialing a controlled delivery of RLN stimulation and assessing durability of any observed responses.

Recurrent laryngeal motor nerve conduction studies in a rat model: Establishing an objective measure for investigating laryngeal innervation

INTRODUCTION/AIMS

Disease or injury can cause neuromuscular changes to the larynx that can affect voice, breathing, and swallowing. Motor nerve conduction studies have had limited use in the study of laryngeal neurophysiology, despite their importance in other anatomic sites. The aim of this study was to explore the feasibility of performing recurrent laryngeal motor nerve conduction studies (rlMNCS) in a rat model.

METHODS

rlMNCS were performed in 15 rats under anesthesia. A bipolar stimulating electrode was placed on the recurrent laryngeal nerve (RLN) 5 mm below the cricoid cartilage. Via direct laryngoscopy, a recording electrode was placed transorally into the thyroarytenoid muscle. The RLN was maximally stimulated to determine the compound muscle action potential (CMAP). Three consecutive trials were averaged.

RESULTS

The mean stimulating threshold to the RLN to achieve a CMAP from the thyroarytenoid was 1.7 ± 0.6 mA. RLN stimulation caused a visible adductor twitch of the vocal fold in all animals. The mean negative amplitude was 2.0 ± 0.8 mV, and the total area was 1.0 ± 0.4 mV ms. The CMAP latency and negative duration were 1.0 ± 0.1 ms and 0.9 ± 0.2 ms, respectively.

DISCUSSION

rlMNCS are feasible and may be useful in understanding laryngeal neurophysiology with disease or injury. This work could provide a tractable animal model for studying and monitoring treatment of neuromuscular conditions affecting voice, breathing, and swallowing.

Clinical Experiences of Speech-Language Pathologists in the Rehabilitation of Unilateral Vocal Fold Paralysis

PURPOSE

Unilateral vocal fold paralysis (UVFP) is a neurological voice disorder that is often first treated by a speech-language pathologist (SLP). In literature, little consensus is found regarding voice therapy onset, duration, frequency, and content. The aim of the current study is to investigate the clinical practice of SLPs for treatment of UVFP regarding diagnostics and treatment characteristics. Additionally, the study examined the personal experiences of SLPs regarding UVFP care.

METHOD

An online survey was completed by 37 respondents, all SLPs with experience in treating UVFP. Demographic characteristics, experiences with voice assessments and treatment modalities were examined. Lastly, experiences and opinions of SLPs on evidence-based practice and their own clinical practice were surveyed.

RESULTS

Almost all respondents used a multidimensional voice assessment with findings from laryngovideostroboscopy to assess UVFP. Laryngeal electromyography is not yet integrated in regular clinical practices. The most commonly used vocal techniques were resonant voice exercises, laryngeal manipulation, semioccluded vocal tract exercises (SOVTEs), vocal hygiene, and Vocal Function Exercises, with SOVTEs most often considered effective. A total of 75% of the respondents feel confident treating UVFP, and 87.6% believe it is important to stay updated on evidence-based practice. Variation in therapy timing and dosage was observed, and 48.4% of SLPs usually started early voice therapy within 4 weeks after UVFP onset.

CONCLUSION

Flemish SLPs generally feel confident treating UVFP patients and show interest in improving evidence-based practice. Initiatives to train clinicians further in UVFP care and encouraging SLPs to provide practice-based evidence will enhance the knowledge base for evidence-based practice in UFVP.

Augmentation-lateralization for Unilateral Vocal Fold Palsy With Airway Obstruction: A New Concept in Laryngology

OBJECTIVES

This study presents an efficient, safe, effective, and novel technique of reconstructive transoral laser microsurgery (R-TLM) for the treatment of unilateral vocal fold paralysis (UVFP) with airway obstruction. It is based on the augmentation of the immobile and potentially flaccid and atrophic side while lateralizing the arytenoid and posterior part of the vocal fold, thus improving breathing without sacrificing phonation and commonly improving it.

STUDY DESIGN

Retrospective cohort study through data from medical records and operative notes.

METHODS

Patients with UVFP with exertional dyspnea with or without dysphonia were included in this report. The vocal fold is augmented by harvesting the aryepiglottic fold soft tissues and the upper part of the arytenoid and placing them into the paraglottic space as a pedicled microflap, thus augmenting the anterior two thirds of the vocal fold while lateralizing the remaining arytenoid and posterior third of the vocal fold by an internal traction suture to improve airway. Postoperative breathing, phonation and swallowing were assessed.

RESULTS

Twenty two cases are reported in the study. Follow-up evaluations ranged from 6 to 12 months. All cases showed successful and durable improvement of breathing and phonation. None required tracheostomy or gastrostomy pre- or postoperatively.

CONCLUSIONS

Augmentation-lateralization is a novel, safe, and effective minimally invasive technique that allows airway improvement with good results on phonation in patients with challenging UVFP with airway obstruction.

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.

The Causes and Laryngeal Electromyography Characteristics of Unilateral Vocal Fold Paralysis

OBJECTIVE

To investigate the causes and laryngeal electromyography (LEMG) characteristics of unilateral vocal fold paralysis (UVFP).

METHODS

We retrospectively analyzed the history and LEMG of 337 patients with unilateral vocal fold immobility. The etiology was reviewed and the characteristics of LEMG (including spontaneous potential, recruitment potential, evoked potential, synkinesia, and et al.) were analyzed.

RESULTS

The causes included injury (177 cases, 52.5%), idiopathic causes (72 cases, 21.4%), infection (61 cases, 18.1%), tumor and compressive factors (27 cases, 8.0%). Among the injury group, 161 cases were caused by surgery (111 cases of thyroid surgery), and 16 cases were caused by trauma. LEMG showed that complete nerve injury was present in 72.9% of the injury group, 66.7% of the tumors or compressive factors group, 49.2% of the infection group, and 44.4% of the idiopathic group. Of the 337 patients, 136 patients (40.4%) had synkinesia in the posterior cricoarytenoid muscles, and only two of these patients also had synkinesia in the thyroarytenoid muscles. The proportion of complete recurrent laryngeal nerve (RLN) injury in patients with synkinesia was higher than that of patients without synkinesia.

CONCLUSION

The main cause of vocal fold paralysis is neck surgery, most commonly thyroid surgery. Patients with different causes of paralysis had different severities of RLN injury. LEMG showed that surgery or trauma accounted for the highest proportion of complete nerve injury. Patients with severe RLN injury were more prone to synkinesia, and the posterior cricoarytenoid muscles were more likely to have synkinesia than the thyroarytenoid muscles.

Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure

Damage to the recurrent laryngeal nerve (RLN) caused by supraphysiological compression or tension imposed by adjacent tissue structures, such as the aorta, may contribute to onset of idiopathic unilateral vocal fold paralysis (iUVP) resulting in difficulty speaking, breathing, and swallowing. We previously demonstrated in adolescent pigs that the right RLN epineurium exhibits uniform composition of adipose tissue, with larger quantities along its length within the neck region in contrast to the left RLN that shows greater collagen composition in the thoracic region and greater quantities of adipose tissue in the neck region. In contrast, the epineurium in piglets was primarily composed of collagen tissue that remained uniform along the length of the left and right RLNs. Tensile testing of the left and right RLN in piglets and pigs showed associated differences in strain by RLN side and segment by age. The goal of this study was to investigate how external hydrostatic compression of the RLN affects the nerve's connective tissue and microstructure. RLN segments were harvested from the distal (cervical/neck) regions and proximal (subclavian for the right RLN, thoracic for the left RLN) regions from eight adolescent pigs and nine piglets. RLN segments were isolated and assessed under fluid compression to test hypotheses regarding epineurium composition and response to applied forces. Second harmonic generation (SHG) imaging of epineurial collagen was conducted at 0, 40, and 80 mmHg of compression. The cartesian strain tensor, principal strain (Eps1), and principal direction of the RLN collagen fibers were determined at each pressure step. Significantly larger values of the 1st principal strain occurred in the proximal segments of the pig left RLN when compared to the same segment in piglets (p = 0.001, pig = 0.0287 [IQR = 0.0161 - 0.0428], piglet = 0.0061 [IQR = 0.0033 - 0.0156]). Additionally, the median transverse strain Eyy) for the second pressure increment was larger in the right proximal segment of pigs compared to piglets (p < 0.001, pig = 0.0122 [IQR = 0.0033 - 0.0171], piglet = 0.0013 [IQR = 0.00001 - 0.0028]). Eyy values were significantly larger in the right proximal RLN versus the left proximal RLNs in pigs but not in piglets (p < 0.001). In contrast to piglets, histological analysis of pig RLN demonstrated increased axial alignment of epineurial and endoneurial collagen in response to compressive pressure. These findings support the hypothesis that the biomechanical response of the RLN to compressive pressure changed from being similar to being different between the right and left RLNs during development in the porcine model. Further investigation of these findings associated with age-related onset of idiopathic UVP may illuminate underlying etiologic mechanisms. STATEMENT OF SIGNIFICANCE: Damage to the recurrent laryngeal nerve (RLN) caused by compression imposed by the aorta may contribute to the onset of left-sided idiopathic unilateral vocal fold paralysis resulting in difficulty speaking, breathing, and swallowing. The goal of this study was to investigate how compression affects the connective tissue and microstructure of the RLN. We quantified the pressure induced deformation of the RLN using multiphoton imaging as a function of both location (proximal versus distal) and age (piglets, adolescent pigs). Our results demonstrate that the biomechanical response of the RLN to compression changes in the right versus left RLN throughout development, providing further evidence that the the left RLN is exposed to increasing dynamic loads with age.

Larynx proteomics after jellyfish collagen IL : Increased ECM /collagen and suppressed inflammation

Objectives/Hypothesis

Compare proteomic profiles of rabbit vocal folds (VFs) injected with micronized cross‐linked jellyfish collagen “collagen Type 0” (MX‐JC) against two clinical products for injection medialization laryngoplasty (IL).

Study Design

Animal model.

Methods

Left recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received (MX‐JC) and adipose‐derived stem cells (ADSCs), Group 2, MX‐JC alone; Group 3, cross‐linked hyaluronic acid; and Group 4, micronized acellular dermis. Animals were sacrificed at 4 and 12 weeks. Proteomic profiling of injected versus noninjected VFs by nano‐liquid chromatography, tandem mass spectrometry, and reactome gene ontology analysis was performed.

Results

Overall, 37–61 proteins were found to be upregulated and 60–284 downregulated in injected versus non‐injected VFs (>1.5 fold, false discovery rate‐adjusted p < .05). Over‐representation analysis (% of total) revealed top up‐regulated pathways at 4 and 12 weeks, respectively: Group 1, keratan sulfate metabolism (46%) and cellular processes (29%); Group 2, extracellular matrix (ECM)/collagen processes (33%) and beta oxidation (39%); Group 3, cellular processes (50%) and energy metabolism (100%); and Group 4, keratan sulfate metabolism (31%) and inflammation (50%). Top downregulated pathways were: Group 1, Inflammation (36%) and glucose/citric acid metabolism (42%); Group 2, cell signaling (38%) and glucose/citric acid metabolism (35%); Group 3, keratan sulfate metabolism (31%) and ECM/collagen processes (48%); and Group 4, glucose/citric acid metabolism (33%) and ECM/collagen processes (43%).

Conclusions

MX‐JC “collagen Type 0” upregulates pathways related to ECM/collagen formation and downregulates pathways related to inflammation suggesting that it is promising biomaterial for IL.

Level of Evidence

NA

Office-Based Structural Autologous Fat Injection Laryngoplasty for Unilateral Vocal Fold Paralysis

Unilateral vocal fold paralysis (UVFP) is a common cause of incomplete glottic closure, leading to significant somatic and social disabilities. Office-based autologous fat injection laryngoplasty (AFIL) has been proposed as an effective treatment for glottic insufficiency but has not been well-studied for UVFP. We enrolled 23 patients who underwent office-based structural AFIL due to unilateral vocal paralysis at our institution between February 2021 and January 2022. In the procedure, autologous fat was harvested and injected into the vocal fold under the guidance of flexible digital endoscopy for structural fat grafting. The voice handicap index-10 (VHI-10) score and perceptual voice measurements were collected before the operation, 2 weeks postoperatively, and 3 months postoperatively. Twenty-two patients were followed-up for at least 3 months. The VHI-10 score improved significantly from 29.65 ± 8.52 preoperatively to 11.74 ± 7.42 at 2 weeks (p < 0.0001) and 5.36 ± 6.67 at 3 months (p < 0.0001). Significant improvements in grades of dysphonia (p < 0.0001), breathiness (p < 0.0001), and asthenia (p = 0.004) were also noted at 3 months postoperatively when perceptual measurements were investigated. Office-based structural AFIL is an effective treatment for improving voice-related disability for UVFP patients.

Treatment Options and Voice Outcomes for Patients With Unilateral Vocal Fold Paralysis After Thyroidectomy

Objectives

This study investigated the treatment options and clinical outcomes of voice therapy (VT), hyaluronic acid (HA) injection, autologous fat injection (FI), and medialization thyroplasty (MT) in patients with unilateral vocal fold paralysis (UVFP) after thyroidectomy.

Study Design

Retrospective case series.

Setting

A tertiary teaching hospital.

Methods

This study included 51 patients with post-thyroidectomy UVFP who underwent VT (n = 20), HA injection (n = 14), FI (n = 12), or MT (n = 5) from January 2016 to June 2021. The treatment outcomes were evaluated using 10-item voice handicap index (VHI-10), maximal phonation time (MPT), and auditory perceptual rating using GRB scales (i.e., grade, roughness, and breathiness) before and 3 to 6 months after treatment.

Results

Patients received HA injection presented a significantly shorter interval after thyroidectomy (mean: 4.6 months), followed by VT (6.7 months), FI (12.3 months), and MT (22.4 months). The results exhibited improvement in most of the outcomes after all of the four treatments. Additional comparisons indicated that VHI-10 scores improved the most among patients receiving MT, followed by HA, FI, and VT. The differences of MPT and GRB scores among the 4 treatment groups were non-significant.

Conclusions

The results revealed that VT, HA, FI, and MT can all improve the voice outcomes of patients with post-thyroidectomy UVFP. The optimal treatment approach should be individualized according to the patient's preference and vocal demand, and the interval between thyroidectomy and intervention.

Vocal fold paralysis following first dose of Oxford-AstraZeneca coronavirus disease 2019 vaccine

BACKGROUND

In a bid to end the ongoing coronavirus disease 2019 pandemic, many countries, including the UK, have rolled out mass immunisation programmes. While considered generally safe and effective, vaccines against coronavirus disease 2019 have been reported to be associated with rare and potentially adverse reactions and side effects.

CASE REPORT

This paper reports an unusual case of a patient who developed a unilateral vocal fold paralysis shortly after receiving the first dose of the Oxford-AstraZeneca ChAdOx1 nCov-19 vaccine.

CONCLUSION

To our knowledge, this is the first reported case of vocal fold paralysis following administration of the Oxford-AstraZeneca vaccine. The authors support the position that currently approved coronavirus disease 2019 vaccines remain safe and effective; however, further surveillance and vigilance using real-world data are highly encouraged.

Impact of COVID-19 on vocal cord mobility: a case series study

Background

The World Health Organization (WHO) has declared the pandemic of COVID-19 infection in March 2020, most of cases presented with mild symptoms, and a significant number of cases showed variable neurological pictures. Vocal cord paralysis with no clear cause is termed as idiopathic vocal cord paralysis and supposed to be caused by viral infection. This is a case series study; data were collected prospectively from patients presented to the ENT clinic of Kasr Alainy (Cairo university) and Railway hospitals. Patients presented with defective vocal cord movement with concurrently or recently passed COVID-19 infection were reported from March 2020 to April 2021.

Results

Authors have reported 6 cases of vocal cord paralysis mainly unilateral due to COVID-19 infection as an only clear cause within 14 months. Age ranges from 39 to 69 years, 2 males and 4 females. Patients presented with different clinical scenarios. Follow-up of the cases showed spontaneous recovery in 5 cases and one case underwent cord medialization.

Conclusion

Viral infection could be an underlying cause of idiopathic laryngeal cord paralysis; in the new era of the COVID-19 pandemic, physicians all over the world noticed variable neurological pictures; in this study, we presented 6 cases of vocal cord paralysis mainly unilateral supposed to be due to COVID-19 infection; all cases showed spontaneous recovery apart from one case that needed medialization of the cord.

Iatrogenic Vocal Fold Paralysis: A Population-Based Cohort Study in Taiwan

OBJECTIVE

Iatrogenic vocal fold paralysis is an important issue in laryngology, yet there are few population-based studies regarding the epidemiology. This study used a nationwide population-based claims database (the National Health Insurance Research Database) to investigate the epidemiology of iatrogenic unilateral and bilateral vocal fold paralysis (UVFP/BVFP) among the general adult population in Taiwan.

METHOD

This study analyzed patients (20-90 years old) who underwent thyroid, parathyroid, thoracic, cardiac, or anterior cervical spine operations with vocal fold paralysis among adults in Taiwan from January 1, 2007 to December 31, 2013. The codes for vocal fold paralysis were defined by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Claims data in the Taiwan National Health Insurance Research Database were used.

RESULTS

The most commonly performed operations which were related to vocal fold paralysis in Taiwan were, in descending order of frequency, thyroid, cervical spine, cardiac, thoracic (esophagectomy), and parathyroid operations. The operations that put laryngeal nerves at risk (ONRs) most commonly associated with a diagnosis of UVFP were, in descending order of frequency, thoracic, thyroid, parathyroid, cardiac, and cervical spine. For both UVFP and BVFP, the most commonly associated age group was 51 to 60. For both UVFP and BVFP, the more commonly associated sex was women. Increased length of stay was associated with a higher incidence of UVFP and BVFP. Charlson medical co-morbidity index (CCI) was not associated with UVFP but BVFP was associated with higher Charlson medical co-morbidity scores.

CONCLUSIONS

Thyroid operations, age 51 to 60, longer hospital stays are associated with vocal fold paralysis. Overall women are more surgically affected than men. This is the first population-based study of iatrogenic vocal fold paralysis.

Characteristics, natural evolution and surgical treatment outcomes of unilateral laryngeal paralysis versus ankylosis: A longitudinal cohort study

AIMS

Although unilateral laryngeal immobility (ULI) can results from paralysis or ankylosis of the cricoarytenoid joint, no comparative study exists to date. Aim of this study was to compare clinical features, aetiologies, spontaneous recovery and evolution after surgical treatment of ULI according to its mechanism.

METHODOLOGY

Longitudinal observational cohort study between 1992 and 2017 in a tertiary care referral centre and university teaching hospital. All adult patients with isolated ULI were included. Presenting symptoms and demographic data were recorded at baseline. During follow-up, natural recovery and, if a surgical treatment was performed, treatment failure rate were noted.

RESULTS

994 patients were included, 56.4% of male and with a mean age of 58 years. Overall, 91% had paralysis and 9% had ankylosis. Dysphonia was the main symptom in both groups (>96%). Dyspnoea was more frequent in patients with ankylosis (26.1% vs 4.2% in those with paralysis) whereas dysphagia was more frequent in those with paralysis (31.1% vs 20% in those with ankylosis). With a mean follow-up of 2.3 years (±5.1), spontaneous recovery did not differ according to ULI's aetiology (hazard ratio 1.43, 95% confidence interval 0.85-2.40). Overall, 37.1% underwent a surgical treatment, and paralysis was associated with a lower odd of treatment failure (hazard ratio 0.27, 95% confidence interval 0.10-0.70) over a mean follow-up of 3.1 years (±4.1).

CONCLUSION

ULI resulting from paralysis or ankylosis differ in their symptoms and responses to surgical treatment, whereas natural evolution was similar.

MRI Study of Jellyfish Collagen, Hyaluronic Acid, and Cadaveric Dermis for Injection Laryngoplasty

OBJECTIVES/HYPOTHESIS

Test a new jellyfish collagen biomaterial aimed to increase duration of injection medialization laryngoplasty (IL) against two products in clinical practice.

STUDY DESIGN

Animal model.

METHODS

Left recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received micronized cross-linked jellyfish collagen (MX-JC) and adipose derived stem cells (ADSCs), Group 2, MX-JC alone, Group 3, cross-linked hyaluronic acid (X-HA), and Group 4, micronized acellular dermis (MACD). Animals were sacrificed at 4 and 12 weeks. Major outcomes were MRI tissue volumes and histopathology.

RESULTS

After 100 μL IL MRI volumes (means ± STD) at 4 and 12 weeks were: Group 1: 27.2 ± 15.6 and 13.1 ± 5.2 μL, Group 2: 60.8 ± 18 and 27.8 ± 2.47 μL, Group 3: 27.4 ± 12 and 10.6 ± 8 μL, and Group 4: 37.5 ± 11 and 9.85 ± 1 μL. Group 2 volumes were largest and Group 3 were smallest in all comparisons (P < .05). Histologically, low grade inflammatory responses were observed in Group 1, mild histiocytic infiltration in Group 2, widespread muscle fiber loss in Group 3, and plasmocytic infiltration in Group 4.

CONCLUSIONS

MX-JC showed the least resorption at 4 and 12 weeks among all groups. T cell inflammatory responses were observed with MX-JC but were reduced by 12 weeks while B cell immune responses, indicative of antibody priming, were predominantly noted with MACD. MX-JC + ADSC showed low grade immunity while the XHA showed greater myocyte loss compared to the other groups.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E2452-E2460, 2021.

Vocal Fold Motion Impairment Following Chemotherapy Administration: Case Reports and Review of the Literature

OBJECTIVE

Chemotherapy-induced vocal fold motion impairment (CIVFMI) is a rare complication of cancer therapy with potential for airway compromise. The objective of this review is to present 2 new cases of CIVFMI to add to the literature as well as characterize the demographics, symptoms, exam findings, airway complication rates and prognosis of CIVFMI.

METHODS

A search of Pubmed/MEDLINE (1970 to May 1, 2020), Embase (1970 to May 1, 2020), and Cochrane Library using medical study heading (MeSH) terms related to chemotherapy (drug therapy, chemotherapy, vincristine, vinblastine, paclitaxel) and vocal cord motion impairment (vocal cord, cords, vocal folds, immobility, hypomobility) was performed. Exploratory pooling of data without formal meta-analysis was performed.

RESULTS

A preliminary search yielded 148 abstracts, review articles and studies. A total of 23 studies met inclusion criteria. There were 35 total cases presented in the literature, with a mean age of 29.5 (0.4-78). The most common cancer diagnosis was acute lymphoblastic leukemia (n = 15, 42.9%), and the most common agent was vincristine (n = 30, 85.7%). Dysphagia, bilateral CIVFMI, and vocal fold immobility rather than hypomobility were more common in pediatric patients. There were 8 cases of surgical airway intervention, including tracheostomy and posterior cordotomy. The duration of symptoms was 7 to 420 days, and spontaneous resolution was reported in 32 cases.

CONCLUSIONS

CIVFMI has potential for airway complications requiring surgical intervention. Spontaneous resolution after cessation of the offending agent is the most likely outcome. Bilateral CIVFMI, dysphagia and vocal fold immobility are more common in the pediatric population.

Natural Course of Unilateral Vocal Fold Paralysis and Optimal Timing of Permanent Treatment

Importance

Permanent surgical treatment for unilateral vocal fold paralysis (UVFP) should be performed when further neural recovery is improbable. Conservative delay of the surgical procedure may cause unnecessary deterioration of the patient's quality of life. Knowledge of the natural course of UVFP is important for better management and counseling.

Objective

To evaluate the natural course of UVFP, focusing on the recovery time according to the injury level to assess the optimal timing for permanent surgical intervention.

Design, Setting, and Participants

This retrospective case series enrolled 1264 patients with UVFP who visited the voice clinic of Seoul National University Hospital, Seoul, Korea, from November 1, 2005, through December 31, 2016. Medical records and stroboscopic video images were reviewed to obtain data on demographic characteristics, vocal fold movement, onset and recovery time, follow-up duration, and cause. Cases of UVFP were classified into 5 groups based on the location of injury: distal to the thyroid level, thyroid level, esophagus and mediastinum level, heart and lung level, and proximal to the thorax level. Data analysis was performed from January 23, 2018, to May 21, 2018.

Main Outcomes and Measures

Recovery of vocal fold movement defined as more than vocal fold twitching confirmed by stroboscopy video images, estimated injury level, and start time of recovery. The recovery time was analyzed according to age, sex, paralytic side, and 5 injury levels.

Results

Of 1264 eligible patients with UVFP (655 [51.8%] male; median age, 56 years [range, 1-90 years]), 208 had evidence of recovery with the recovery time relatively accurate. The maximum recovery time for the group with distal to the thyroid-level injury was 120 days; the group with thyroid-level injury, 157 days; the group with esophagus and mediastinum-level injury, 244 days; the group with heart and lung-level injury, 328 days; and the group with proximal to the thorax-level injury, 333 days with the exception of 1 outlier value (482 days). Recovery time did not differ according to age, sex, or paralytic side. As distance between the vocal fold and injury level increased, the maximum recovery time increased, plateauing at 1 year. Among the patients who showed recovery of the vocal fold movement, most patients with injuries distal to or at the level of the thyroid recovered within 6 months, whereas those with injury more distant from the vocal fold recovered within approximately 1 year.

Conclusions and Relevance

A linear association between injury level and maximum recovery time was observed. The findings suggest that the decision to proceed with permanent phonosurgical treatment should be based on the level of injury associated with UVFP.

Vocal Fold Immobility Following Vaccination

OBJECTIVE

Vocal fold immobility (VFI) may severely affect quality of life due to dysphonia and respiratory distress. Many etiologies of this disorder have been evaluated, however the relationship between VFI and vaccination has yet to be explored. The objective of this study was to identify the relationship between VFI and vaccine administration.

METHODS

The Vaccine Adverse Event Reporting System (VAERS) database was queried for patients exhibiting symptoms of VFI following vaccination. Patient demographics and clinical information including presenting symptoms, time of symptom onset, laterality, outcomes, and adverse events were documented.

RESULTS

Twenty-two patients were found to have VFI following vaccination. Of those reported, 13 patients were female (59.1%) and 8 were male (36.4%) with an average age of 48.4 years. Vaccinations for influenza, shingles, pneumococcus, and hepatitis B were reported. A majority of these cases were unilateral in nature (73.3%). Mean lag time from vaccination to symptom onset was 6.3 days (range 0-45 days). Five adverse events were reported, with 4 patients requiring intubation and tracheostomy.

CONCLUSION

Vaccine administration may be associated with VFI and physicians should be cognizant of this potential adverse event. This is a rare complication with less reported cases than other post-vaccination cranial neuropathies. The difficulty in establishing an initial diagnosis and need for specialized evaluation by an otolaryngologist may result in under-reporting of such events. Further research is needed to delineate the exact pathophysiology of this complication and determine whether a causal relationship exists.

Yield of Imaging to Evaluate Unilateral Vocal Fold Paralysis of Unknown Etiology

OBJECTIVES/HYPOTHESIS

To identify the incidence and nature of positive findings on imaging studies ordered for evaluation of unilateral vocal fold paralysis (UVFP) of unknown etiology, to analyze these findings based on laterality, and to examine the use of the expanded-field computed tomography (CT) neck protocol in this evaluation.

STUDY DESIGN

Retrospective review.

METHODS

A total of 145 patients from 2000 to 2018 with UVFP of unknown etiology were studied. Data on imaging studies ordered, laterality of paralysis, and significant positive results were studied. An expanded-field CT neck protocol that included the entire course of the vagus and recurrent laryngeal nerves was instituted during the study period.

RESULTS

A total of 20.7% of patients had an etiology for paralysis identified on imaging. Malignancies comprised the majority of findings overall (19/30), whether in the chest (12/18) or the neck (7/12). Etiology was more often found in the chest for left-sided paralysis (15/21) and in the neck for right-sided paralysis (6/9). In 26 patients who underwent both expanded-field CT neck and CT chest, no findings related to the UVFP were seen on CT chest that were not captured by expanded-field CT neck.

CONCLUSIONS

This is one of the largest retrospective studies examining the incidence of positive findings on imaging studies for evaluation of UVFP of unknown etiology. Imaging in one of five patients with UVFP of unknown etiology will reveal a causative lesion, most often malignant. Left-sided paralysis tends to localize to the chest, and right-sided paralysis to the neck. Expanded-field CT neck may allow practitioners to forego dedicated CT chest in evaluation of UVFP.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1840-1844, 2021.

Development of In-Office Laryngeal Nerve Conduction Studies: Computed Tomography and Cadaveric Study

OBJECTIVES/HYPOTHESIS

In-office recurrent laryngeal nerve conduction studies (NCSs) are a technique that can potentially provide information about laryngeal innervation. NCS is essential in the management of other neuropathies including carpal tunnel syndrome and spinal cord injury. We hypothesize that laryngeal NCS may have similar utility in managing patients with vocal fold paralysis, atrophy, and neurodegenerative disease. NCSs are technically challenging because they require transcervical stimulation of the recurrent laryngeal nerve (RLN). This study combines radiographic data with cadaveric dissection to describe the anatomic parameters for optimal RLN stimulation.

STUDY DESIGN

Radiographic and Cadaveric Study.

METHODS

Fifty computed tomography scans were reviewed to determine the dimensions for ideal needle electrode placement. These values were compared to measurements from 12 fresh human cadaveric neck dissections. Ultrasound imaging was utilized in select cases. The neck was dissected to assess the accuracy of electrode placement.

RESULTS

Radiographically, the mean transcervical depth to the RLN was 33.2 mm ± 8.3 mm in males versus 29.4 mm ± 9.4 mm in females. The working space between the lateral trachea and carotid artery was 15.3 mm ± 3.6 mm on the right and 14.1 mm ± 2.9 mm on the left. After placement of stimulating electrodes into the cadaveric neck, the electrode tips were consistently within 8 mm of the RLN. Ultrasound guidance improved placement accuracy of the stimulating electrode.

CONCLUSIONS

Laryngeal NCSs can provide detailed and objective information about laryngeal innervation that could dramatically improve the management of various neuropathies. In-office NCSs require technical precision, and this study describes anatomic factors that may affect the feasibility of performing this technique.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:1566-1569, 2021.

Cardiothoracic Patients with Unilateral Vocal Fold Paralysis: Pneumonia Rates Following Injection Laryngoplasty

Objective:

Recurrent laryngeal nerve injury is a potential complication of cardiothoracic surgery and cause of unilateral vocal fold paralysis (UVFP). Injection laryngoplasty (IL) is an intervention offered to patients with UVFP to alleviate symptoms including dysphagia, dysphonia and weak cough. There is no definitive evidence that IL prevents pneumonia. In this study, we compare rates of pneumonia in patients with UVFP secondary to cardiothoracic surgery who did or did not undergo IL.

Methods:

A retrospective chart review identified patients diagnosed with UVFP by an otolaryngologist using flexible laryngoscopy following cardiothoracic surgery from January 1, 2008 to December 31, 2017. Each subject was grouped by IL status and assessed for subsequent pneumonia within 6 months of their diagnosis of UVFP. The association of IL with pneumonia was evaluated using Cox proportional hazards regression.

Results:

Of 92 patients who met inclusion criteria, 35 (38%) underwent IL and 57 (62%) did not. Twenty patients developed pneumonia, four who had undergone IL and 16 who had not; 12 patients developed aspiration pneumonia including two having undergone IL and 10 who had not. Those who had IL were less likely to develop total pneumonia compared to those who had not (HR = 0.33, P = .045). The protective effect of IL was not as clearly sustained when measuring for aspiration pneumonia, specifically (HR = 0.34; P = .10).

Discussion:

Injection laryngoplasty may reduce the risk of pneumonia in patients with UVFP secondary to cardiothoracic surgery; however, further research is needed to quantify the potential protective nature of IL in this patient population.

Level of evidence:

3 (A retrospective cohort study).

Study protocol to develop a patient-reported outcome measuring disability associated with unilateral vocal fold paralysis: a mixed-methods approach with the CoPE collaborative

INTRODUCTION

Patient-reported outcome (PRO) measures are increasingly developed with multisite, representative patient populations so that they can serve as a primary endpoint in clinical trials and longitudinal studies. Creating multisite infrastructure during PRO measure development can facilitate future comparative effectiveness trials. We describe our protocol to simultaneously develop a PRO measure and create a collaborative of tertiary care centres to address the needs of patients with unilateral vocal fold paralysis (UVFP). We describe the stakeholder engagement, information technology and regulatory foundations for PRO measure development and how the process enables plans for multisite trials comparing treatments for this largely iatrogenic condition.

METHODS AND ANALYSIS

The study has three phases: systematic review, measure development and measure validation. Systematic reviews and qualitative interviews (n=75) will inform the development of a conceptual framework. Qualitative interviews with patients with UVFP will characterise the lived experience of the condition. Candidate PRO measure items will be derived verbatim from patient interviews and refined using cognitive interviews and expert input. The PRO measure will be administered to a large, multisite cohort of adult patients with UVFP via the CoPE (vocal Cord Paralysis Experience) Collaborative. We will establish CoPE to facilitate measure development and to create preliminary infrastructure for future trials, including online data capture, stakeholder engagement, and the identification of barriers and facilitators to participation. Classical test theory psychometrics and grounded theory characterise our approach, and validation includes assessment of latent structure, reliability and validity.

ETHICS AND DISSEMINATION

Our study is approved by the University of Wisconsin Health Sciences Institutional Review Board. Findings from this project will be published in open-access journals and presented at international conferences. Subsequent use of the PRO measure will include comparative effectiveness trials of treatments for UVFP at CoPE Collaborative sites.

Life Experience of Patients With Unilateral Vocal Fold Paralysis

Importance

Clinicians and patients benefit when they have a clear understanding of how medical conditions influence patients' life experiences. Patients' perspectives on life with unilateral vocal fold paralysis have not been well described.

Objective

To promote patient-centered care by characterizing the patient experiences of living with unilateral vocal fold paralysis.

Design, Setting, and Participants

This study used mixed methods: surveys using the voice and dysphagia handicap indexes (VHI and DHI) and semistructured interviews with adults with unilateral vocal cord paralysis recruited from a tertiary voice center. Recorded interviews were transcribed, coded using a hierarchical coding system, and analyzed using an iterative inductive-deductive approach.

Main Outcomes and Measures

Symptom domains of the patient experience.

Results

In 36 patients (26 [72%] were female, and the median age and interquartile range [IQR] were 63 years [48-68 years]; median interview duration, 42 minutes), median VHI and DHI scores were 96 (IQR, 77-108) and 55.5 (IQR, 35-89) at the time of interviews, respectively. Frustration, isolation, fear, and altered self-identity were primary themes permeating patients' experiences. Frustrations related to limitations in communication, employment, and the medical system. Sources of fear included a loss of control, fear of further dysfunction or permanent disability, concern for health consequences (eg, aspiration pneumonia), and/or an inability to call for help in emergency situations. These experiences were modified by the following factors: resilience, self-efficacy, perceived sense of control, and social support systems.

Conclusions and Relevance

Effects of unilateral vocal fold paralysis extend beyond impaired voice and other somatic symptoms. Awareness of the extent to which these patients experience frustration, isolation, fear, and altered self-identity is important. A patient-centered approach to optimizing unilateral vocal fold paralysis treatment is enhanced by an understanding of both the physical dimension of this condition and how patients cope with the considerable emotional and social consequences. Recognizing the psychosocial dimensions of disease allows clinicians to communicate more effectively, be more empathetic, and to better personalize treatment plans, which may lead to improved patient care and patient satisfaction.

[Thyroid tumors in the adult revealed by unilateral laryngeal paralysis]

GOAL

To analyze the characteristic of thyroid tumor associated with ipsilateral unilateral laryngeal paralysis (ULP) in the adult patient.

MATERIALS AND METHODS

Retrospective analysis of a cohort of 30 patients with ULP related to an ipsilateral thyroid tumor (group A) and comparison with a cohort of 99 patients in whom ULP revealed a non-thyroid tumor (group B).

RESULTS

Group A consisted of 66.6% of women with a mean age of 69 years. Comparison between both groups noted that female gender was more frequent in group A (66.6% vs. 17.1%, P<0.0001), and the underlying tumor was more frequently malignant in group B (89.9% vs. 43.4%, P<0.0001). Within group A, the incidence for recovery of laryngeal motion varied form 0% for malignant tumor to 50% for benign tumor. In patients with a benign thyroid tumor in whom recovery of laryngeal motion did not occur, the watch policy initiated allowed to detect a pathology (malignant tumor or neurological) explaining persistent ULP in 57% of cases.

CONCLUSION

The present series confirm that ULP in the face of thyroid tumor does not allow to distinguish formally between benign and malignant tumors and highlight the value of a long term watch policy in patients with benign thyroid tumor pathology in whom recovery of laryngeal mobility does not occur.

Morphometric Differences in the Recurrent Laryngeal Nerve in Patients with Vocal Fold Paralysis

OBJECTIVES

Injury to the recurrent laryngeal nerve (RLN), if severe enough, can result in vocal fold paralysis. Reinnervation surgery can improve patient outcomes, but previous studies have reported a negative correlation between time since onset of paralysis and surgical outcomes. The ability of the paralyzed nerve to serve as a conduit for donor nerve fibers may be a factor in the success of reinnervation; however, changes in RLN composition after paralysis have not been well studied. Therefore, we investigated the morphometric composition of explanted RLN sections from patients who had experienced vocal fold paralysis for varying length of times.

METHODS

Nine nerve sections from unilateral vocal fold paralysis (UVP) patients and seven control nerve sections were analyzed for morphometric parameters including fascicular area, fiber count, fiber density, fiber packing, mean g-ratio, and fiber diameter distribution. Nerves from UVP patients were also compared as a function of time since UVP onset.

RESULTS

In comparison to control nerves, paralyzed nerves were found to have significantly lower fiber densities and fiber packing, higher mean g-ratio values, and a shift in diameter distributions toward smaller diameter fibers. With respect to paralysis duration, no significant differences were observed except in fiber diameter distributions, where those with paralysis for >2 years had distributions that were significantly shifted toward smaller diameter fibers.

CONCLUSIONS

The morphometric data presented here suggest that correlations between the time since onset of vocal fold paralysis and reinnervation outcomes may be due to fiber size changes in the paralyzed nerve over time.

Clinical Practice Guideline: Hoarseness (Dysphonia) (Update) Executive Summary

Objective This guideline provides evidence-based recommendations on treating patients presenting with dysphonia, which is characterized by altered vocal quality, pitch, loudness, or vocal effort that impairs communication and/or quality of life. Dysphonia affects nearly one-third of the population at some point in its life. This guideline applies to all age groups evaluated in a setting where dysphonia would be identified or managed. It is intended for all clinicians who are likely to diagnose and treat patients with dysphonia. Purpose The primary purpose of this guideline is to improve the quality of care for patients with dysphonia, based on current best evidence. Expert consensus to fill evidence gaps, when used, is explicitly stated and supported with a detailed evidence profile for transparency. Specific objectives of the guideline are to reduce inappropriate variations in care, produce optimal health outcomes, and minimize harm. For this guideline update, the American Academy of Otolaryngology-Head and Neck Surgery Foundation selected a panel representing the fields of advanced practice nursing, bronchoesophagology, consumer advocacy, family medicine, geriatric medicine, internal medicine, laryngology, neurology, otolaryngology-head and neck surgery, pediatrics, professional voice, pulmonology, and speech-language pathology. Action Statements The guideline update group made strong recommendations for the following key action statements (KASs): (1) Clinicians should assess the patient with dysphonia by history and physical examination to identify factors where expedited laryngeal evaluation is indicated. These include but are not limited to recent surgical procedures involving the head, neck, or chest; recent endotracheal intubation; presence of concomitant neck mass; respiratory distress or stridor; history of tobacco abuse; and whether the patient is a professional voice user. (2) Clinicians should advocate voice therapy for patients with dysphonia from a cause amenable to voice therapy. The guideline update group made recommendations for the following KASs: (1) Clinicians should identify dysphonia in a patient with altered voice quality, pitch, loudness, or vocal effort that impairs communication or reduces quality of life (QOL). (2) Clinicians should assess the patient with dysphonia by history and physical examination for underlying causes of dysphonia and factors that modify management. (3) Clinicians should perform laryngoscopy, or refer to a clinician who can perform laryngoscopy, when dysphonia fails to resolve or improve within 4 weeks or irrespective of duration if a serious underlying cause is suspected. (4) Clinicians should perform diagnostic laryngoscopy, or refer to a clinician who can perform diagnostic laryngoscopy, before prescribing voice therapy and document/communicate the results to the speech-language pathologist (SLP). (5) Clinicians should advocate for surgery as a therapeutic option for patients with dysphonia with conditions amenable to surgical intervention, such as suspected malignancy, symptomatic benign vocal fold lesions that do not respond to conservative management, or glottic insufficiency. (6) Clinicians should offer, or refer to a clinician who can offer, botulinum toxin injections for the treatment of dysphonia caused by spasmodic dysphonia and other types of laryngeal dystonia. (7) Clinicians should inform patients with dysphonia about control/preventive measures. (8) Clinicians should document resolution, improvement or worsened symptoms of dysphonia, or change in QOL of patients with dysphonia after treatment or observation. The guideline update group made a strong recommendation against 1 action: (1) Clinicians should not routinely prescribe antibiotics to treat dysphonia. The guideline update group made recommendations against other actions: (1) Clinicians should not obtain computed tomography (CT) or magnetic resonance imaging (MRI) for patients with a primary voice complaint prior to visualization of the larynx. (2) Clinicians should not prescribe antireflux medications to treat isolated dysphonia, based on symptoms alone attributed to suspected gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux (LPR), without visualization of the larynx. (3) Clinicians should not routinely prescribe corticosteroids in patients with dysphonia prior to visualization of the larynx. The policy level for the following recommendation about laryngoscopy at any time was an option: (1) Clinicians may perform diagnostic laryngoscopy at any time in a patient with dysphonia. Differences from Prior Guideline (1) Incorporating new evidence profiles to include the role of patient preferences, confidence in the evidence, differences of opinion, quality improvement opportunities, and any exclusion to which the action statement does not apply (2) Inclusion of 3 new guidelines, 16 new systematic reviews, and 4 new randomized controlled trials (3) Inclusion of a consumer advocate on the guideline update group (4) Changes to 9 KASs from the original guideline (5) New KAS 3 (escalation of care) and KAS 13 (outcomes) (6) Addition of an algorithm outlining KASs for patients with dysphonia.

Efficacy of trans-nasal fiberendoscopic injection laryngoplasty with centrifuged autologous fat in the treatment of glottic insufficiency due to unilateral vocal fold paralysis

SUMMARY

The objective of this work is to evaluate the safety, feasibility and efficacy of trans-nasal fiberendoscopic injection laryngoplasty (IL) with centrifuged autologous fat, performed under local anaesthesia, in the treatment of glottic insufficiency due to unilateral vocal fold paralysis (UVFP). It is a within-subject study with follow-up 1 week after phonosurgery and after 6 months. A total of 22 patients with chronic dysphonia caused by glottic insufficiency due to UVFP were enrolled. Each patient underwent trans-nasal IL with centrifuged autologous fat through flexible operative endoscope under local anaesthesia and was evaluated before and twice (1 week and 6 months) after phonosurgery, using a multidimensional set of investigations. The assessment protocol included videolaryngostroboscopy, perceptual evaluation of dysphonia, maximum phonation time and patient's self-assessment on voice-related quality of life (QOL) with the Voice Handicap Index-10 and the comparative self-assessment on vocal fatigue and voice quality pre-post treatment. Trans-nasal IL with centrifuged autologous fat was performed in all 22 patients and there were no complications in any case. Significant improvements in videolaryngostroboscopic findings, perceptual evaluation of dysphonia, maximum phonation time and QoL self-assessment were reported after 1 week and were maintained at 6 months. In one patient, the result after 6 months was not satisfactory and this patient then underwent a medialization laryngoplasty (thyroplasty type I) with satisfactory long-term results. In conclusion, trans-nasal fiberendoscopic IL with centrifuged autologous fat seems to be a safe, feasible and efficacious phonosurgical procedure for treatment of glottic insufficiency due to unilateral vocal fold paralysis.

Vocal Fold Motion Recovery in Patients With Iatrogenic Unilateral Immobility: Cervical Versus Thoracic Injury

Objectives:

Prognostic information about the return of vocal fold mobility in patients with iatrogenic unilateral vocal fold immobility (UVFI) can help with informed decisions about temporary and permanent treatment options. Although many variables can influence the likelihood of recovery, clinical experience suggests that cervical versus thoracic injury is a determining factor. The purpose of this study was to compare recovery rates from UVFI between cervical and thoracic injuries.

Methods:

A retrospective review of the medical record was performed on all adult patients diagnosed with complete iatrogenic UVFI from 2005 to 2015 (n = 923). Patients with incomplete data and etiologies of idiopathic, malignancy, or stenosis were excluded, leaving a study cohort of 502 patients who were categorized as having UVFI after cervical (n = 329) or thoracic (n = 173) injury. Data regarding site of iatrogenic injury (cervical vs thoracic), mobility status, and time interval to recovery or surgical intervention were recorded and compared using χ2 analyses.

Results:

Overall, 15% of patients recovered vocal fold mobility at a median of 4.1 months. Patients with cervical injury (65 of 329 [20%]) were significantly more likely to recover mobility than patients with thoracic injury (11 of 173 [6.4%]) (odds ratio, 3.63). The cervical cohort contained more women (68% vs 31%) and was younger (mean age, 60.4 ± 13.8 vs 64.1 ± 16.1 years; Cohen’s D = 0.25).

Conclusions:

Patients with cervical injuries resulting in UVFI are 4 times more likely to recover mobility than patients with thoracic injuries. This information can be valuable in counseling patients with UVFI and may affect clinical decision making.

Risk factors for thyroid surgery-related unilateral vocal fold paralysis

Objectives/Hypothesis

We aimed to identify the risk factors for iatrogenic unilateral vocal fold paralysis (UVFP) caused by thyroid surgery, to allow the identification of patients requiring nerve‐protection procedures and monitoring technologies.

Study Design

Retrospective case study in a medical center.

Methods

Patients who underwent thyroid surgery from April 2011 to February 2016 and who were diagnosed with UVFP by laryngoscopy and laryngeal electromyography were included. Patient demographics, types of surgery, and characteristics of the thyroid lesions were analyzed.

Results

Sixty (2.1%) of 2,815 patients who received thyroid surgery developed UVFP. The risk of UVFP was higher in patients over 60 years old (odds ratio, 1.89; 95% confidence interval, 1.01‐3.26; P = .01). Involvement of the external branch of superior laryngeal nerve (EBSLN) occurred in 19 (31.7%) of the 60 UVFP patients, and was more likely to occurr in patients with diabetes mellitus (odds ratio, 14.19; 95% confidence interval, 3.80‐52.94; P < .001). The incidence of UVFP and involvement of the EBSLN differed among surgery types, and was the highest among patients undergoing total thyroidectomy with neck dissection (TTND) (10/158, 6.3% and 5/158, 3.2%, respectively).

Conclusions

The risk of thyroid surgery–related UVFP is higher in older patients. EBSLN involvement is more likely in patients with diabetes mellitus. TTND is associated with higher risks of UVFP and EBSLN injury than other types of surgery, implying the need of intraoperative nerve monitoring in these high‐risk characteristics.

Level of Evidence

4 Laryngoscope, 129:275–283, 2019

Association between Upper Respiratory Infection and Idiopathic Unilateral Vocal Fold Paralysis

INTRODUCTION

Unilateral vocal fold paralysis (UVFP) without an identifiable cause is termed idiopathic unilateral vocal fold paralysis (IUVFP). Some authors have postulated that select cases of IUVFP have a viral etiology, but the causality has not been established. We set out to review institutional cases of IUVFP and determine if there is a correlation between upper respiratory infection symptoms and presentation of IUVFP.

METHODS

Cases of IUVFP were reviewed over a 10-year period (2002-2012). The history was investigated to review presenting symptoms. We specifically reviewed for symptoms of upper respiratory infection at the onset of UVFP and tallied the frequency. Symptoms included sore throat, laryngitis, cough, influenza, bronchitis, pneumonia, otalgia, and sinusitis. The seasonal onset (if possible) was determined based on the history provided from the initial consultation.

STUDY DESIGN

Case series.

RESULTS

Overall, 107 patients presented with IUVFP; 35.5% of patients reported symptoms of upper respiratory infection at the onset of UVFP. Among these individuals, pharyngitis/laryngitis was the most common presenting symptom; 34.2% reported cough. In total, 40.0% of patients with IUVFP reported an onset of symptoms between December and February.

CONCLUSIONS

This study suggests that symptoms of upper respiratory infection frequently occur with the presentation of IUVFP. The onset of symptoms tended to occur between December and February. The mechanism of viral-mediated UVFP has not been established. Future studies to explore this pathophysiology are needed.

Compound Motor Action Potential Measures Acute Changes in Laryngeal Innervation

Objective:

Vocal fold paralysis is caused by injury to the recurrent laryngeal nerve (RLN). Current clinical measures of laryngeal innervation are often nonquantitative. Compound motor action potentials (CMAP) measure motor innervation. The goal of this study was to determine whether CMAP can quantify laryngeal innervation following acute nerve injury.

Study Design:

Animal study.

Methods:

Twelve canine hemilaryngeal preparations were used. The RLN was serially stimulated with increasing intensities until the nerve was maximally stimulated. The CMAP amplitude was measured for each intensity stimulation and correlated. Next, the RLN was incompletely transected, and the reduction in CMAP amplitude was correlated to the percentage of transected axons. The percentage of transected axons was determined using horseradish peroxidase (HRP) staining.

Results:

Combining all hemilaryngeal preparations, the submaximal stimulation of the RLN linearly correlated with the resultant CMAP amplitude (r = 0.83; 95% CI, 0.76-0.88). Following partial RLN transection, the percentage of remaining axons linearly correlated with the CMAP amplitude (r = 0.87; 95% CI, 0.34-0.98).

Conclusions:

CMAP amplitude is a quantitative measure that may correlate with the degree of vocal fold innervation in canines. Following RLN injury, CMAP may help clinicians quantify the number of intact axons, assess the likelihood of recovery, and counsel patients on their prognosis.

Botulinum Toxin Injection in the Treatment of Postextubation Dysphagia: A Case Report

Prolonged intubation is known to bring on postextubation dysphagia (PED) in some patients. We have noted that there were some studies to investigate specific type and pattern of PED, which showed large variety of different swallowing abnormalities as mechanisms of PED that are multifactorial. There are several options of treatment in accordance with the management of these abnormalities. A botulinum toxin (BoT) injection into the upper esophageal sphincter (UES) can improve swallowing functions for patients with this disorder, by working to help the muscle relax. In this case, the conventional treatment was not effective in patients with PED, whereas the BoT injection made a great improvement for these patients. This study suggests that the UES pathology could be the main cause of PED.

Symptomatic unilateral vocal fold paralysis following cardiothoracic surgery

PURPOSE

Unilateral vocal fold paralysis (UVFP) is a complication associated with cardiothoracic procedures that presents clinically as dysphonia and/or dysphagia with or without aspiration. The literature lacks both data on recovery of mobility and consensus on best management. Herein, our goals are to 1) Identify cardiothoracic procedures associated with symptomatic UVFP at our institution; 2) Review timing and nature of laryngology diagnosis and management; 3) Report spontaneous recovery rate of vocal fold mobility.

MATERIALS AND METHODS

Retrospective case series at single tertiary referral center between 2002 and 2015. 141 patients were included who underwent laryngology interventions (micronized acellular dermis injection laryngoplasty and/or type 1 thyroplasty) to treat symptomatic UVFP diagnosed subsequent to cardiothoracic surgery.

RESULTS

Pulmonary procedures were most often associated with UVFP (n=50/141; 35.5%). 87.2% had left-sided paralysis (n=123/141). Median time to diagnosis was 42days (x¯=114±348). Over time, UVFP was diagnosed progressively earlier after cardiothoracic surgery. 63.4% of patients (n=95/141) underwent injection laryngoplasty as their initial intervention with median time from diagnosis to injection of 11days (x¯=29.6±54). 41.1% (n=58/141) ultimately underwent type 1 thyroplasty at a median of 232.5days (x¯=367±510.2) after cardiothoracic surgery. 10.2% (n=9/88) of those with adequate follow-up recovered full vocal fold mobility.

CONCLUSIONS

Many cardiothoracic procedures are associated with symptomatic UVFP, predominantly left-sided. Our data showed poor recovery of vocal fold mobility relative to other studies. Early diagnosis and potential surgical medialization is important in the care of these patients.

Clinical Practice Guideline: Hoarseness (Dysphonia) (Update)

Objective

This guideline provides evidence-based recommendations on treating patients who present with dysphonia, which is characterized by altered vocal quality, pitch, loudness, or vocal effort that impairs communication and/or quality of life. Dysphonia affects nearly one-third of the population at some point in its life. This guideline applies to all age groups evaluated in a setting where dysphonia would be identified or managed. It is intended for all clinicians who are likely to diagnose and treat patients with dysphonia.

Purpose

The primary purpose of this guideline is to improve the quality of care for patients with dysphonia, based on current best evidence. Expert consensus to fill evidence gaps, when used, is explicitly stated and supported with a detailed evidence profile for transparency. Specific objectives of the guideline are to reduce inappropriate variations in care, produce optimal health outcomes, and minimize harm. For this guideline update, the American Academy of Otolaryngology—Head and Neck Surgery Foundation selected a panel representing the fields of advanced practice nursing, bronchoesophagology, consumer advocacy, family medicine, geriatric medicine, internal medicine, laryngology, neurology, otolaryngology–head and neck surgery, pediatrics, professional voice, pulmonology, and speech-language pathology.

Action Statements

The guideline update group made strong recommendations for the following key action statements (KASs): (1) Clinicians should assess the patient with dysphonia by history and physical examination to identify factors where expedited laryngeal evaluation is indicated. These include, but are not limited to, recent surgical procedures involving the head, neck, or chest; recent endotracheal intubation; presence of concomitant neck mass; respiratory distress or stridor; history of tobacco abuse; and whether the patient is a professional voice user. (2) Clinicians should advocate voice therapy for patients with dysphonia from a cause amenable to voice therapy. The guideline update group made recommendations for the following KASs: (1) Clinicians should identify dysphonia in a patient with altered voice quality, pitch, loudness, or vocal effort that impairs communication or reduces quality of life (QOL). (2) Clinicians should assess the patient with dysphonia by history and physical examination for underlying causes of dysphonia and factors that modify management. (3) Clinicians should perform laryngoscopy, or refer to a clinician who can perform laryngoscopy, when dysphonia fails to resolve or improve within 4 weeks or irrespective of duration if a serious underlying cause is suspected. (4) Clinicians should perform diagnostic laryngoscopy, or refer to a clinician who can perform diagnostic laryngoscopy, before prescribing voice therapy and document/communicate the results to the speech-language pathologist (SLP). (5) Clinicians should advocate for surgery as a therapeutic option for patients with dysphonia with conditions amenable to surgical intervention, such as suspected malignancy, symptomatic benign vocal fold lesions that do not respond to conservative management, or glottic insufficiency. (6) Clinicians should offer, or refer to a clinician who can offer, botulinum toxin injections for the treatment of dysphonia caused by spasmodic dysphonia and other types of laryngeal dystonia. (7) Clinicians should inform patients with dysphonia about control/preventive measures. (8) Clinicians should document resolution, improvement or worsened symptoms of dysphonia, or change in QOL of patients with dysphonia after treatment or observation. The guideline update group made a strong recommendation against 1 action: (1) Clinicians should not routinely prescribe antibiotics to treat dysphonia. The guideline update group made recommendations against other actions: (1) Clinicians should not obtain computed tomography (CT) or magnetic resonance imaging (MRI) for patients with a primary voice complaint prior to visualization of the larynx. (2) Clinicians should not prescribe antireflux medications to treat isolated dysphonia, based on symptoms alone attributed to suspected gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux (LPR), without visualization of the larynx. (3) Clinicians should not routinely prescribe corticosteroids for patients with dysphonia prior to visualization of the larynx. The policy level for the following recommendation about laryngoscopy at any time was an option: (1) Clinicians may perform diagnostic laryngoscopy at any time in a patient with dysphonia.

Disclaimer

This clinical practice guideline is not intended as an exhaustive source of guidance for managing dysphonia (hoarseness). Rather, it is designed to assist clinicians by providing an evidence-based framework for decision-making strategies. The guideline is not intended to replace clinical judgment or establish a protocol for all individuals with this condition, and it may not provide the only appropriate approach to diagnosing and managing this problem. Differences from Prior Guideline (1) Incorporation of new evidence profiles to include the role of patient preferences, confidence in the evidence, differences of opinion, quality improvement opportunities, and any exclusion to which the action statement does not apply (2) Inclusion of 3 new guidelines, 16 new systematic reviews, and 4 new randomized controlled trials (3) Inclusion of a consumer advocate on the guideline update group (4) Changes to 9 KASs from the original guideline (5) New KAS 3 (escalation of care) and KAS 13 (outcomes) (6) Addition of an algorithm outlining KASs for patients with dysphonia

Aortic arch compliance and idiopathic unilateral vocal fold paralysis

Unilateral vocal fold paralysis (UVP) occurs related to recurrent laryngeal nerve (RLN) impairment associated with impaired swallowing, voice production, and breathing functions. The majority of UVP cases occur subsequent to surgical intervention with approximately 12-42% having no known cause for the disease (i.e., idiopathic). Approximately two-thirds of those with UVP exhibit left-sided injury with the average onset at ≥50 yr of age in those diagnosed as idiopathic. Given the association between the RLN and the subclavian and aortic arch vessels, we hypothesized that changes in vascular tissues would result in increased aortic compliance in patients with idiopathic left-sided UVP compared with those without UVP. Gated MRI data enabled aortic arch diameter measures normalized to blood pressure across the cardiac cycles to derive aortic arch compliance. Compliance was compared between individuals with left-sided idiopathic UVP and age- and sex-matched normal controls. Three-way factorial ANOVA test showed that aortic arch compliance (P = 0.02) and aortic arch diameter change in one cardiac cycle (P = 0.04) are significantly higher in patients with idiopathic left-sided UVP compared with the controls. As previously demonstrated by other literature, our finding confirmed that compliance decreases with age (P < 0.0001) in both healthy individuals and patients with idiopathic UVP. Future studies will investigate parameters of aortic compliance change as a potential contributor to the onset of left-sided UVP.NEW & NOTEWORTHY Unilateral vocal fold paralysis results from impaired function of the recurrent laryngeal nerve (RLN) impacting breathing, swallowing, and voice production. A large proportion of adults suffering from this disorder have an idiopathic etiology (i.e., unknown cause). The current study determined that individuals diagnosed with left-sided idiopathic vocal fold paralysis exhibited significantly greater compliance than age- and sex-matched controls. These seminal findings suggest a link between aortic arch compliance levels and RLN function.

Paclitaxel inhibits post-traumatic recurrent laryngeal nerve regeneration into the posterior cricoarytenoid muscle in a canine model

OBJECTIVES/HYPOTHESIS

To investigate the efficacy of paclitaxel, a potent microtubule inhibitor with a more favorable therapeutic index as compared with vincristine, in preventing post-traumatic nerve regeneration of the recurrent laryngeal nerve into the posterior cricoarytenoid muscle in a canine laryngeal model.

STUDY DESIGN

Experimental animal study.

METHODS

Forty-nine canine hemilaryngeal specimens were divided into five experimental groups. Under general anesthesia, a tracheostomy, recurrent laryngeal nerve (RLN) transection and repair, and laryngeal adductory pressures (LAP) were measured pre-RLN injury. The approach to the posterior cricoarytenoid (PCA) muscle for neurotoxin injection was transoral or open transcervical, at 0 or 3 months. At 6 months, postinjury LAPs were measured and the animals were sacrificed at 6 months to allow for laryngeal harvesting and analysis.

RESULTS

Paclitaxel demonstrated increased mean laryngeal adductory pressures (70.6%) as compared with saline control (55.5%). The effect of paclitaxel was the same as observed with vincristine at 0 months and with a delayed injection at 3 months. There was no difference between transoral or open injection groups.

CONCLUSIONS

PCA muscle injection with paclitaxel resulted in improved strength of laryngeal adduction. This effect was similar to that of vincristine at both 0 and 3 months following nerve injury. A single intramuscular injection of paclitaxel was well tolerated. Additional human studies are needed to determine the degree of clinical benefit of this intervention.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:651-655, 2017.

A retrospective evaluation of the etiology of unilateral vocal fold paralysis over the last 25 years

Previous studies have shown that the etiology of laryngeal paralysis has changed over the last decades, with an increase in the incidence of cases attributable to thyroid surgery. The aim of this study was to evaluate longitudinal changes in the etiology of unilateral vocal fold paralysis (UVFP) in a single institution over the last 25 years. This retrospective study analyzed the etiology of UVFP between 1990 and 2015 by comparing a cohort of patients treated in 1990-1992 with a cohort treated in 2013-2015. The final analysis was based on data concerning 356 patients (38.8 % males; mean age 55.3 ± 20.4 years): 113 in the 1990-1992 cohort, and 243 in the 2013-2015 cohort. The main cause of UVFP in the population as a whole was thyroidectomy (41.3 %), followed by an idiopathic origin (25.3 %) and thoracic surgery (12.1 %); this was confirmed in both intra-group analyses. There was a statistically significant association between etiology and the sub-group periods: the prevalence of post-thyroidectomy UVFP was highly significantly lower in the 2013-2015 cohort (35.4 vs 54.0 %), and the prevalence of idiopathic cases was higher (28.4 vs 18.6 %). Etiology significantly related to gender in both cohorts (p value ≤0.001). In the 2013-2015 cohort, there was also a statistically significant relationship between etiology and age classes (p value 0.017), and the left side was more frequently affected than the right (67.1 vs 32.9 %). Our findings document changes in the etiological pattern of UVFP over the last 25 years, with a considerable decrease in post-thyroidectomy UVFP, and a growing predominance of idiopathic and post-thoracic surgery UVFP.

Distinct Disease and Functional Characteristics of Thyroid Surgery-Related Vocal Fold Palsy

BACKGROUND

Iatrogenic trauma induced by thyroid surgery is the most common etiology of unilateral vocal fold paralysis (UVFP). UVFP after thyroid surgery may lead to profound physical and psychosocial distress. This study comprehensively evaluated UVFP caused by thyroid surgery, and compared the results with those caused by other surgical trauma.

METHODS

Patients with surgery-related UVFP were evaluated using quantitative laryngeal electromyography, videolaryngostroboscopy, voice acoustic analysis, the Voice Outcome Survey, and the Short Form-36 Health Survey quality-of-life questionnaire. Patients with thyroid surgery and other surgeries were compared.

RESULTS

A total of 105 patients were recruited, of whom 52 and 53 were assigned to the thyroid surgery and the other surgery group, respectively. Patients in the thyroid surgery group had a higher proportion of external branch of superior laryngeal nerve (eSLN) involvement, longer duration from disease onset to the first laryngeal electromyography examination, lower jitter, higher harmonic-to-noise ratio, and better quality of life compared with the other surgery group. Specifically for patients in the thyroid surgery group, those with eSLN involvement tended to have more pronounced impairment in jitter and shimmer compared with patients without eSLN involvement.

CONCLUSION

UVFP caused by thyroid surgery has a distinct clinical presentation with relatively high involvement in the eSLN, better voice acoustics, longer waiting time before asking for evaluation, and less impact on quality of life. The involvement of eSLN in these patients further impaired their voice. Early referral is suggested for these patients, especially with suspected eSLN injury.

Predictors for Permanent Medialization Laryngoplasty in Unilateral Vocal Fold Paralysis

OBJECTIVE

Early differentiation of patients with unilateral vocal fold paralysis (VFP) who recover from those who do not and consequently require permanent medialization laryngoplasty (ML) remains a challenge. The goal of this study is to identify factors that predict the need for ML.

STUDY DESIGN

Case series with chart review.

SETTING

Academic center.

SUBJECTS AND METHODS

A total of 507 records of patients with VFP were analyzed, of which 252 met criteria and were stratified according to whether or not they obtained ML. Demographic information and clinical features were analyzed to determine predictors of ML. A nomogram was generated according to the significance and utility of these parameters.

RESULTS

Of 252 patients, 86 underwent ML, and 166 did not. No differences in age or sex were observed between the ML and non-ML patients (P = .27 and P = .35, respectively). The most common cause of VFP was iatrogenic injury (62.79%, ML; 49.40%, non-ML). ML correlated with VFP secondary to neoplastic disease (odds ratio [OR], 2.14; 95% confidence interval [95% CI], 1.01-4.53) and iatrogenic injury (OR 1.73; 95% CI 1.01-2.94). ML had an inverse correlation with idiopathic VFP (OR, 0.40; 95% CI, 0.20-0.79). Patients in the ML group were more likely to have left-sided VFP, to have a history of aspiration, and to present ≥90 days from onset and less likely to have had temporary injection augmentation.

CONCLUSION

Clinical features may be used to predict the likelihood of a patient obtaining ML. Nomograms may be useful to counsel patients who would benefit from early definitive surgery.