Ultrasound prediction for vocal cord dysfunction in patients scheduled for anterior cervical spine surgeries: a prospective cohort study

Imaging Characteristics and Reference Values of the Vocal Cords in Chinese Adults Based on High-Frequency Ultrasound

OBJECTIVE

To elucidate the imaging characteristics of and establish reference values for measurement parameters of the vocal cords in healthy volunteers.

METHODS

A total of 1000 healthy Han Chinese adults (694 women) aged 18-79 y will be enrolled between October 2023 and April 2024. The length and width of vocal cord abduction and adduction and vocal cord thickness were measured, and the widening and shortening rates of vocal cord adduction were calculated as indicators of vocal cord motor function. The data were stratified by age group and sex. The correlations of vocal cord measurements with age, height, weight, BMI and BSA were analyzed.

RESULTS

The parathyroid section clearly revealed the vocal cord structure. Image quality decreases with age. Normal reference ranges (from the 2.5th to the 97.5th percentile) were established for vocal cord abduction length, adduction length, abduction width, adduction thickness, shortening rate and broadening rate based on data from 638 healthy adults: males: 13.98-28.17 mm, 11.33-21.21 mm, 2.90-5.66 mm, 5.65-7.44 mm, 3.16-6.18 mm, 9.97%-44.31% and 14.13%-137.78%, respectively; females: 12.55-19.42 mm, 9.59-14.80 mm, 3.40-4.80 mm, 5.65-7.90 mm, 3.40-4.90 mm, 10.05%-39.34% and 32.88%-102.66%, respectively. Vocal cord length, width, thickness, shortening rate and broadening rate were not correlated with age, height, weight, BMI or BSA.

CONCLUSION

This study summarized the characteristics of and initially established reference values for quantitative parameters of the vocal cords, ultimately providing reference values for the clinic.

The impact of anesthesia instruments and drugs on the occurrence of vocal cord injury, systematic review and meta-analysis

OBJECTIVE

This study extensively examined common complications related to anesthesia drugs and equipment on vocal cords. It also delved into factors such as smoking, anesthesia duration and anesthesia induction methods. Overall, the research aimed to pinpoint influential factors for creating a general anesthesia protocol with minimal post-operative complications.

MATERIALS AND METHODS

We searched PubMed, Scopus, Web of Science, and Google Scholar for studies concerning the impact of anesthesia drugs and equipment on the vocal cord, until May 2023. after screening and reviewing of full text, the characteristics of the study including sample size, age, dosage or size of anesthesia drugs and equipment, Duration of intervention, Adverse effects, and Maintenance of adverse effects, were extracted. The quality assessment was done using the Newcastle-Ottawa scale and the Jadad Scale.

RESULTS

Our review included 39 studies from 1983 to 2023. The most frequent VCAEs were cough‎ (39.17%; CI = 9.84-68.51)‎, hoarseness (‎35.32%; CI = 25.04-45.60)‎, and erythema (35.09%; CI=-4.84-75.02). VC paralysis was relatively less frequent (‎4.16%; CI = 2.90-5.43)‎. Meta-regression showed no difference in the frequency of VCAEs with or without single-lung ventilation and smoking. However, the duration of procedure was shown to be affecting three outcomes; the duration shorter than 120 min is associated with lower rates of granuloma (2.74% vs. 44.30%; p < 0.05) and higher rates of cough (48.89% vs. 15.91%; p < 0.05) and VC paralysis (42.86% vs. 0.12%; p < 0.05). The overall outcomes were not affected.

CONCLUSIONS

The most common anesthesia-related VCAEs are cough, erythema, and dysphagia, while serious complications like vocal cord hematoma and paralysis are rare. Also surgery duration significantly influences VCAE occurrence.

Vocal cord dysfunction/inducible laryngeal obstruction: novel diagnostics and therapeutics

INTRODUCTION

Vocal cord dysfunction/inducible laryngeal obstruction (VCD/ILO) is an important medical condition but understanding of the condition is imperfect. It occurs in healthy people but often co-exists with asthma. Models of VCD/ILO pathophysiology highlight predisposing factors rather than specific mechanisms and disease expression varies between people, which is seldom appreciated. Diagnosis is often delayed, and the treatment is not evidence based.

AREAS COVERED

A unified pathophysiological model and disease phenotypes have been proposed. Diagnosis is conventionally made by laryngoscopy during inspiration with vocal cord narrowing >50% Recently, dynamic CT larynx was shown to have high specificity (>80%) with potential as a noninvasive, swift, and quantifiable diagnostic modality. Treatment entails laryngeal retraining with speech pathology intervention and experimental therapies such as botulinum toxin injection. Multidisciplinary team (MDT) clinics are a novel innovation with demonstrated benefits including accurate diagnosis, selection of appropriate treatment, and reductions in oral corticosteroid exposure.

EXPERT OPINION

Delayed diagnosis of VCD/ILO is pervasive, often leading to detrimental treatments. Phenotypes require validation and CT larynx can reduce the necessity for laryngoscopy, thereby fast-tracking diagnosis. MDT clinics can optimize management. Randomized controlled trials are essential to validate speech pathology intervention and other treatment modalities and to establish international standards of care.

Laryngeal Ultrasound Detects Vocal Fold Immobility in Adults: A Systematic Review

Laryngeal ultrasound (US) is becoming widely accepted for assessing true vocal fold immobility (TVFI), a potential complication of laryngeal and thyroid surgery. The objective of this project is to perform a systematic review and meta-analysis of pooled evidence surrounding laryngeal US as a modality for diagnosing TVFI in adults at risk for the condition in comparison to laryngoscopy as a gold standard. Medical subject heading terms were used to search MEDLINE, Embase, Google Scholar, Web of Science, and the Cochrane Library for relevant citations from January 1, 2000, to June 30, 2020. Studies were included if they involved patients 16 years and older, where laryngeal US was compared to laryngoscopy for TVFI. Studies were excluded if there were insufficient data to compute a sensitivity/specificity table after attempting to contact the authors. Case reports, and case series were also excluded. The initial search returned 1357 citations. Of these, 109 were selected for review utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Thirty citations describing 6033 patients were included in the final meta-analysis. A bivariate random effects meta-analysis was performed, revealing a pooled sensitivity for laryngeal US of 0.95 (95% confidence interval [CI] 0.88-0.98), a specificity of 0.99 (95% CI 0.97-0.99), and a diagnostic odds ratio of 1328.2 (95% CI 294.0-5996.5). The area under the curve of the hierarchical summary receiver operating characteristic curve was 0.99 (95% CI 0.98-1.00). Laryngeal US demonstrates high sensitivity and specificity for detecting VFI in the hands of clinicians directly providing care to patients.