Functional analysis of vocal folds by transcutaneous laryngeal ultrasonography in patients undergoing thyroidectomy

Quantitative Assessment of True Vocal Fold Movement by the Lateral-Approach Laryngeal Ultrasonography: A Pilot Study

BACKGROUND/OBJECTIVES

Ultrasonography is a new method for subjective and qualitative assessment of true vocal fold movement, and true vocal fold visualization with the lateral approach could be better than that with the anterior approach. Our aim was to explore the feasibility of lateral-approach ultrasonography in objective and quantitative assessment of true vocal fold movement.

METHODS

The lateral-approach laryngeal ultrasonography was performed during calm breathing and breath-holding on young healthy adult volunteers in Shanghai, China. The morphology and anatomical position of false vocal fold, true vocal fold, and arytenoid cartilage were observed and measured through the ultrasonic self-contained measurement function. All parameters, including the distance from false vocal fold to thyroid cartilage lamina, true vocal fold length, and the distance from true vocal fold to thyroid cartilage lamina, were obtained at the end of the calm inspiratory and breath-holding phases. Data were analyzed using a t test (P < 0.05).

RESULTS

Forty healthy adult volunteers (age 20 to 34 years, body mass index 19.5 to 23.8 kg/m2, 20 males and 20 females) with satisfactory ultrasonic images were included in the study. There were no significant differences in all laryngeal parameters between the left and right sides in either phase (P > 0.05). From the end of the calm inspiratory phase to the breath-holding phase, changes in all laryngeal parameters were significantly different (P < 0.05), regardless of gender.

CONCLUSIONS

This study demonstrated that the lateral-approach laryngeal ultrasonography seemed feasible to quantify and objectively assess true vocal fold movement, utilizing differences between laryngeal parameters before and after true vocal fold movement.

Techniques of detecting recurrent laryngeal nerve palsy in patients undergoing thyroid surgery: Pearls and pitfalls

Though permanent vocal cord palsy consequent to recurrent laryngeal nerve (RLN) injury is rare following thyroidectomies, its consequences are grave enough for it to be the most feared complication postoperatively. Anesthesiologists and surgeons take various precautions to prevent its occurrence and employ various methods for its early detection. They include direct visualization of the nerve intraoperatively, use of intraoperative nerve monitoring, and post-extubation visualization of vocal cord mobility by use of direct or indirect methods. In the present narrative review, we aim to discuss the clinical evidence pertaining to the various methods adopted for the prevention and early detection of RLN palsy during thyroidectomy.

Normative data for certain vocal fold biomarkers among young normophonic adults using ultrasonography

PURPOSE

The current study aimed to profile vocal fold morphology, vocal fold symmetry, gender and task-specific data for vocal fold length (VFL) and vocal fold displacement velocity (VFDV) in young normophonic adults in the age range of 18-30 years using ultrasonography (USG).

METHODS

Participants underwent USG across quiet breathing, /a/ phonation and /i/ phonation tasks, and acoustic analysis was conducted to explore the relationship between USG and acoustic measures.

RESULTS

The study found that males have longer vocal folds than females, and overall greater velocities were observed in /a/ phonation, followed by /i/ phonation, with the lowest velocity observed in the quiet breathing task.

CONCLUSIONS

The obtained norms can be used as a quantitative benchmark for analyzing the vocal fold behavior in young adults.

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.

Application of Translaryngeal Ultrasound (TLUS) in Patients with Neck Surgery—A Single-Centre, Prospective Cohort Study on Technique Evaluation

Purpose: The primary objective of this study was to assess the value of translaryngeal ultrasound (TLUS) in assessing vocal fold (VF) function in patients after thyroid, parathyroid and neck lymph node surgery. Methods: A total of 219 patients that underwent 230 surgical procedures were enrolled in this prospective study. The study was conducted from October 2020 to October 2021. Patients’ VFs were analysed independently with TLUS and laryngoscopy before and after the surgery. Various TLUS variables, such as vocal folds displacement velocity (VFDV), arytenoids symmetry and angle between VFs, were measured. The questionnaire evaluating discomfort caused to patients by both methods was conducted. Results: Of the 230 surgeries in this study, 85% were from oncological indications. The incidence of RLN injury was 10.4%. The accuracy of TLUS compared to laryngoscopy was 98.3%, with sensitivity 98.1%, specificity 100%, PPV 100% and NPV 83.3%. Laryngoscopy was found to cause significantly more discomfort than TLUS. VF visibility was lower in men; smokers; and patients with higher BMI (32 vs. 28 kg/m²), multifocal cancer, higher left lobe volume and higher fT3 levels. Arytenoid symmetry VFDV was lower for “e” and “i” right side and “i” left side in injured/disabled VFs/RLN. Conclusions: TLUS can be an excellent and non-invasive method of VF evaluation in most patients. There are some technical aspects that can improve its accuracy. Sometimes, RLN injury after the surgery, especially among oncological patients, is unavoidable. Therefore, it is vital to diagnose dysphonia early with convenient methods, such as TLUS.

Transcutaneous Laryngeal Ultrasonography for Assessing Vocal Cord Twitch Response in Thyroid Operation during Predissection Vagus Nerve Stimulation

BACKGROUND

In this study, we aimed to report our experience with the use of intraoperative transcutaneous laryngeal ultrasonography (TLUSG) to evaluate the vocal cord twitch response during predissection vagus nerve stimulation in thyroid surgeries and examine the reliability of this technique when compared with that of laryngeal twitch palpation (LTP).

STUDY DESIGN

The prospective data collection of consecutive patients who underwent open thyroidectomy with intraoperative neuromonitoring (IONM) was reviewed retrospectively. We recorded the electromyographic activity and assessed the vocal cord twitch response on LTP, TLUSG. We compared the accessibility, sensitivity, and specificity of the techniques.

RESULTS

A total of 110 patients (38 men and 72 women) with 134 nerves at risk were enrolled. The vocal cord was assessable by TLUSG in 103 (93.6%) patients and by LTP in 64 (59.1%) patients. Two patients showed negative predissection IONM signal but positive on TLUSG and the presence of laryngeal twitch response confirmed by laryngoscopy. Fourteen patients showed positive IONM signals and presence of the vocal cord twitch response on TLUSG but not on LTP. The sensitivity and specificity were 70.21% and 100%, respectively, for LTP, and those both were 100% for TLUSG. For patients who could be assessed using both techniques, TLUSG had better accuracy than LTP (100% vs 80.33%, p = 0.0005).

CONCLUSIONS

The innovative intraoperative application of TLUSG is better for evaluating the laryngeal twitch response than LTP. This technique provides practical troubleshooting guidance for patients with no IONM signals during predissection vagus nerve stimulation.

Value of laryngeal ultrasound in comparison with flexible laryngoscope in diagnosis of various laryngeal masses: a cross-sectional study

Background

The term "vocal cord mass" refers to any abnormal growth of the vocal cords. This may include nodules, cysts, polyps, or cancers. Hoarseness of voice is considered the most common symptom of laryngeal lesions. Ultrasound imaging has evolved into a valuable and effective technique for evaluating the head and neck region, including the larynx's structure. Our aim is to evaluate laryngeal ultrasound as an alternative technique to the flexible laryngoscope in the diagnosis and assessment of various laryngeal masses.

Results

The study included 30 males (57.7%) and 22 females (42.3%) who presented with hoarseness of voice. All patients had laryngeal ultrasonography, which was followed by flexible laryngoscopy. The most commonly affected cord was the left vocal cord (42.3%), followed by the right vocal cord (32.7%), and finally both of them (25%). The sensitivity of laryngeal ultrasonography was 88.5% compared to the gold standard flexible laryngoscopy (p value 0.031).

Conclusions

The laryngeal ultrasonography is a highly successful technique in the diagnosis and assessment of various laryngeal masses and could be complementary to flexible laryngoscopy in many cases, especially when laryngoscopy is contraindicated, with relatively high sensitivity in the detection of laryngeal masses.

Transcutaneous Laryngeal Ultrasound for Vocal Cord Paralysis Assessment in Patients Undergoing Thyroid and Parathyroid Surgery-A Systematic Review and Meta-Analysis

Recurrent laryngeal nerve injury is an important complication following thyroid and parathyroid surgery. Recently, Transcutaneous laryngeal ultrasound (TLUSG) has emerged as a non-invasive alternative to laryngoscopic examination for vocal cord (VC) assessment. The aim of the systematic review and meta-analysis was to determine its diagnostic accuracy in reference to laryngoscopy. It was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. MEDLINE, Scopus, Cochrane library and Web of Science databases were searched to identify relevant articles. Sixteen studies were included in the review. Pooled diagnostic accuracy was calculated based on weighted arithmetic mean and plotting forest plot. The pooled visualization rate was 86.28% and 94.13% preoperatively and postoperatively, respectively. The respective pooled sensitivity and specificity was 78.48% and 98.28%, and 83.96% (CI 95%: 77.24-88.50%) and 96.15% (CI 95%: 95.24-96.88%). The diagnostic accuracy improved if transverse and lateral approaches, and valsalva maneuver were utilized. Male gender and older age were the most crucial risk factors for VC non-visualization. TLUSG is an efficacious screening tool for vocal cord palsy due to its high sensitivity. It is likely to prevent unnecessary laryngoscopic examination in around 80% of patients, with the potential for becoming a gold standard for specific (female/young) patient cohort through assimilative modifications use, increasing expertise and development of objective measurements in the future.

Application of Transcutaneous Laryngeal Ultrasonography in the Diagnosis of Vocal Fold Polyps

The aim of this study was to explore the value of transcutaneous laryngeal ultrasonography in the diagnosis of vocal fold polyps. From December 2016 to June 2019, 87 patients with vocal fold polyps diagnosed pathologically in the Otolaryngology Head and Neck Surgery Department of the Second Affiliated Hospital of Xi'an Jiaotong University were enrolled and examined by electronic laryngoscopy and percutaneous laryngeal ultrasound on the same day before operation. To observe the effect of calcification length as a percentage of thyroid cartilage at the glottic level on vocal fold display, the characteristics of ultrasound images of vocal fold polyps and the value of transcutaneous laryngeal ultrasonography in the diagnosis of vocal fold polyps were assessed. Among 87 patients, the calcification rate of thyroid cartilage at the glottic level was 33.3%. The differences in calcification rate and percentage of calcification length between males and females were statistically significant. The rate of detection of vocal folds decreased gradually with an increase in calcification length percentage. Imaging features of vocal fold polyps were hypo-echoic with a clear boundary and regular shape. The detection rates for circular and non-circular polyps were 92.0% and 70.6%. Ultrasound was more likely to detect circular than non-circular polyps; however, the difference was not significant. Transcutaneous laryngeal ultrasonography can identify the morphology and location of vocal fold polyps and is non-invasive and highly accurate. Therefore, it has the potential to be an effective supplement to laryngoscopy for initial screening and post-operative review of vocal fold polyps.

Transcutaneous Laryngeal Ultrasonography for the Assessment of Laryngeal Function After Thyroidectomy: A Review

OBJECTIVE

This review set out to examine the applicability of transcutaneous laryngeal ultrasonography (TLUSG) for the assessment of laryngeal function after thyroidectomy.

METHODS

An integrative review of the literature was performed using Medline/PubMed, LILACS, and SciELO databases. The methodological quality of the studies was analyzed using the appraisal tool for cross-sectional studies.

RESULTS

All 8 included articles investigated laryngeal function with regard to the risk of vocal fold immobility after thyroidectomy. The results regarding the diagnostic power of TLUSG for this assessment are controversial, and there is a tendency to use this examination as a screening procedure for subsequent confirmation by flexible laryngoscopy.

CONCLUSIONS

Transcutaneous laryngeal ultrasonography is a viable, noninvasive, and useful tool to assess laryngeal function after thyroidectomy, but current available evidence suggests that it does not replace flexible laryngoscopy for the diagnosis of vocal fold immobility.