Using Transcutaneous Laryngeal Ultrasonography (TLUSG) to Assess Post-thyroidectomy Patients’ Vocal Cords: Which Maneuver Best Optimizes Visualization and Assessment Accuracy?

Technical Aspects of Transcutaneous Laryngeal Ultrasonography: A Review

IMPORTANCE

Vocal fold palsy is a crucial complication of thyroidectomy. Although laryngoscopic examination is the gold standard for vocal fold assessment, there is a growing interest in incorporating transcutaneous laryngeal ultrasonography (TLUSG) in the peri-operative period. This review provides a detailed technical report on how to efficiently perform TLUSG assessment of the vocal folds.

OBSERVATIONS

The ultrasonographic assessment of vocal folds is based on the recognition and observation of one of three structures: false vocal folds, true vocal folds, and arytenoid cartilages. These structures can be visualized either through the anterior (transverse) approach or the lateral (sagittal) approach. The movement of vocal fold structures is elicited and assessed using three maneuvers, namely passive breathing, active phonation or Valsalva maneuver. This examination can allow adequate visualization and assessment of vocal fold function in the majority of the patients in the peri-operative period.

CONCLUSIONS AND RELEVANCE

This review provides a step-by-step description and algorithmic approach to TLUSG assessment of the vocal folds. It details the common pitfalls and modifications of TLUSG required to assist surgeons, anesthesiologists, and endocrinologists in incorporating this examination in their practice.

Assessment of pre-extubating recurrent laryngeal nerve palsy using ultrasound in postoperative patients with esophageal cancer: a prospective observational study

PURPOSE

Ultrasound performed after extubation has been suggested to be useful for the diagnosis of recurrent laryngeal nerve (RLN) paralysis. However, the use of ultrasound for this purpose before extubation has not been examined. The aim of this study was to examine the versatility (interrater reliability) and usefulness of ultrasound for evaluating the movement of vocal cords before extubation.

METHODS

The subjects were 30 patients who underwent radical surgery for esophageal cancer from August 2020 to December 2021. An experienced examiner performed an ultrasound examination before and after elective extubation on the day after surgery to evaluate RLN paralysis and record videos. Bronchoscopy was then performed to make a definite diagnosis. Three anesthetists blinded to the diagnosis also evaluated the cases using the videos, and the versatility of the examination was determined using a kappa test.

RESULTS

The diagnostic accuracies of the examiner and three anesthetists were 76.7%, 50.0%, 53.3%, and 46.7%, respectively, and the kappa coefficients for the examiner with the anesthetists were 0.310, 0.502, and 0.169, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of RLN paralysis by the examiner using ultrasound before extubation were 0.57, 0.95, 0.80, and 0.87, respectively.

CONCLUSION

These results indicate a lack of versatility of the ultrasound examination based on the low kappa coefficients. However, with an experienced examiner, ultrasound can serve as a non-invasive examination that can be performed before extubation with high accuracy and specificity for diagnosis of postoperative RLN paralysis.

Assessment of vocal fold movement through anterior-posterior view of videofluoroscopic swallowing study

Objective

The aim of this study is to assess the value of using videofluoroscopic swallowing study (VFSS) for assessing vocal fold paralysis.

Methods

This was a retrospective study of patients who underwent VFSS with a vocal fold testing maneuver from June 2020 to February 2022, and who had undergone laryngoscopy within 2 weeks before or after VFSS. The vocal fold testing maneuver consisted of making an 'e' sound for about 2-3 seconds during VFSS anterior-posterior (AP) view. The diagnostic value of the VFSS was evaluated by a trained reviewer, who assessed the presence and laterality of vocal fold paralysis by examining videos of the patients performing the vocal fold testing maneuver. Intra-rater reliability was determined by evaluation of the videos by the same reviewer 2 weeks later, and inter-rater reliability was determined by evaluation by a second reviewer.

Results

Seventy patients were enrolled in the study. The positive predictive value was 91.43% and the intra-rater and inter-rater reliabilities, as determined by Cohen's kappa value, were 0.746 and 0.824 respectively.

Conclusions

The presence and laterality of vocal fold paralysis were identified accurately and reliably by the reviewers, showing that VFSS can be used to assess vocal fold paralysis.

Level of evidence

2.

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.

Pediatric intraoperative nerve monitoring during thyroid surgery: A review from the American Head and Neck Society Endocrine Surgery Section and the International Neural Monitoring Study Group

Children are more likely to experience recurrent laryngeal nerve (RLN) injury during thyroid surgery. Intraoperative nerve monitoring (IONM) may assist in nerve identification and surgical decision making. A literature review of pediatric IONM was performed and used to inform a monitoring technique guide and expert opinion statements. Pediatric IONM is achieved using a variety of methods. When age-appropriate endotracheal tubes with integrated surface electrodes are not available, an alternative method should be used. Patient age and surgeon experience with laryngoscopy influence technique selection; four techniques are described in detail. Surgeons must be familiar with the nuances of monitoring technique and interpretation; opinion statements address optimizing this technology in children. Adult IONM guidelines may offer strategies for surgical decision making in children. In some cases, delay of second-sided surgery may reduce bilateral RLN injury risk.

[Diagnostic efficiency of transcutaneous laryngeal ultrasound in assessing the mobility of vocal cord in patients with thyroid disease]

OBJECTIVE

To assess the diagnostic efficiency of transcutaneous laryngeal ultrasound.

MATERIAL AND METHODS

Ultrasound examination of the larynx and laryngoscopy was performed in 103 patients with thyroid disease. 26 (34.21%) patients who underwent surgery on the thyroid gland direct laryngoscopy and ultrasound of the vocal folds were performed twice, before and after the operation.

RESULTS

Voice folds were visualized in 76 (73.8%) people. Of the 24 men, these anatomical structures were visualized in 8 (33.3%) and in 68 (86.1%) women out of 79 cases. Violations of the function of the vocal cords during laryngoscopy were detected in 5 people, sonographically in 6 people. The coincidence of the revealed pathology with ultrasound was in 4 patients, in 3 - with sonography the diagnosis was erroneous, in 1 patient it was falsely negative and in 2 cases it was falsely positive.

CONCLUSIONS

In connection with the diagnostic capabilities of the method, it is advisable to use it as a screening study in the perioperative period in patients with diseases of the thyroid gland. Laryngoscopy is indicated for patients with non-visualized vocal folds, with identified pathology with ultrasound, and with clinical signs of dysfunction of the vocal cords.

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.

Perioperative transcutaneous laryngeal ultrasonography to assess vocal cord function in thyroid surgery

BACKGROUND

Early diagnosis of vocal cord iatrogenic injury is crucial, as is perioperative vocal cord evaluation.

METHODS

Vocal cord mobility detected via transcutaneous laryngeal ultrasonography was compared with that detected via laryngoscopy (the reference). The vocal cord visualization rate of ultrasonography for evaluation of mobility was explored.

RESULTS

The diagnostic odds ratio of transcutaneous laryngeal ultrasonography was 303.2212 (95% CI, [86.7944; 1059.3198]). The area under the summary receiver operating characteristic curve was 0.944. The sensitivity, specificity, and negative predictive value were 0.9154 [0.8471; 0.9548], 0.9771 [0.9541; 0.9887], and 0.9915 [0.9868; 0.9946], respectively. The vocal cord visualization of ultrasonography used to evaluate vocal cord mobility was high (0.9572 [0.9091; 0.9804]).

CONCLUSIONS

Since transcutaneous laryngeal ultrasonography has the advantage in vocal cord visualization, it can be considered when laryngoscopy is unavailable or patients refuse laryngoscopy. Also, it is diagnostically accurate regardless of the used landmarks, VCP definition, and timing for application.

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

Prediction of vocal cord dysfunction is essential after anterior cervical spine surgeries. This study aimed to detect the validity of transcutaneous laryngeal ultrasonography by both anterior and novel lateral approaches for prediction of vocal cord edema and paralysis after anterior cervical spine surgeries. A prospective cohort study conducted on 90 patients scheduled for anterior cervical spine surgeries underwent consecutive pre and postoperative vocal cord examination for edema and paralysis by both anterior and lateral approaches laryngeal ultrasonography. Rigid laryngoscopy was the standard confirmatory tool. For postoperative vocal cord edema, the anterior ultrasonography approach diagnostic sensitivity = 88.2%, specificity = 78.9% with PPV = 78.9% and NPV = 88.2% and the novel lateral ultrasonography approach diagnostic sensitivity = 88.2%, specificity = 94.7% with PPV = 93.75% and NPP = 90%. While for paralysis, the anterior ultrasonography approach diagnostic sensitivity = 86.7%, specificity = 85.7% with PPV = 81.25% and NPV = 90% and the novel lateral ultrasonography approach diagnostic (sensitivity, specificity with PPV and NPP) = 100%. The diagnostic accuracy of the novel lateral approach was more correlated to rigid laryngoscopy (91.7% and 100%) compared to anterior approach for vocal cord edema and paralysis (83.3% and 80.6%). Overall incidence of vocal cord paralysis was 16.6%. Risk of vocal cord paralysis was statistically significant more in female, multiple disc herniation, lower and mixed disc levels, Langenbeck retractor, cage and plate and duration of surgery ≥ 1.5 h. Transcutaneous Laryngeal ultrasound is a valid comfortable tool for prediction of vocal cord edema and paralysis after anterior cervical spine surgeries with superiority of the novel lateral over anterior approach.

Consensus statement by the American Association of Clinical Endocrinology (AACE) and the American Head and Neck Society Endocrine Surgery Section (AHNS-ES) on Pediatric Benign and Malignant Thyroid Surgery

OBJECTIVES

To provide a clinical disease state review of recent relevant literature and to generate expert consensus statements regarding the breadth of pediatric thyroid cancer diagnosis and care, with an emphasis on thyroid surgery. To generate expert statements to educate pediatric practitioners on the state-of-the-art practices and the value of surgical experience in the management of this unusual and challenging disease in children.

METHODS

A literature search was conducted and statements were constructed and subjected to a modified Delphi process to measure the consensus of the expert author panel. The wording of statements, voting tabulation, and statistical analysis were overseen by a Delphi expert (J.J.S.).

RESULTS

Twenty-five consensus statements were created and subjected to a modified Delphi analysis to measure the strength of consensus of the expert author panel. All statements reached a level of consensus, and the majority of statements reached the highest level of consensus.

CONCLUSION

Pediatric thyroid cancer has many unique nuances, such as bulky cervical adenopathy on presentation, an increased incidence of diffuse sclerosing variant, and a longer potential lifespan to endure potential complications from treatment. Complications can be a burden to parents and patients alike. We suggest that optimal outcomes and decreased morbidity will come from the use of advanced imaging, diagnostic testing, and neural monitoring of patients treated at high-volume centers by high-volume surgeons.

Consensus Statement by the American Association of Clinical Endocrinology (AACE) and the American Head and Neck Society Endocrine Surgery Section (AHNS) on Pediatric Benign and Malignant Thyroid Surgery

OBJECTIVES

To provide a clinical disease state review of recent relevant literature and to generate expert consensus statements regarding the breadth of pediatric thyroid cancer diagnosis and care, with an emphasis on thyroid surgery. To generate expert statements to educate pediatric practitioners on the state-of-the-art practices and the value of surgical experience in the management of this unusual and challenging disease in children.

METHODS

A literature search was conducted and statements were constructed and subjected to a modified Delphi process to measure the consensus of the expert author panel. The wording of statements, voting tabulation, and statistical analysis were overseen by a Delphi expert (J.J.S.).

RESULTS

Twenty-five consensus statements were created and subjected to a modified Delphi analysis to measure the strength of consensus of the expert author panel. All statements reached a level of consensus, and the majority of statements reached the highest level of consensus.

CONCLUSION

Pediatric thyroid cancer has many unique nuances, such as bulky cervical adenopathy on presentation, an increased incidence of diffuse sclerosing variant, and a longer potential lifespan to endure potential complications from treatment. Complications can be a burden to parents and patients alike. We suggest that optimal outcomes and decreased morbidity will come from the use of advanced imaging, diagnostic testing, and neural monitoring of patients treated at high-volume centers by high-volume surgeons.

Ultrasound diagnosis of a case of transient bilateral vocal cord paralysis secondary to local anesthetic infiltration

One of the most important complications associated with thyroid and parathyroid surgery is vocal cord paralysis due to a recurrent laryngeal nerve injury. Recurrent laryngeal nerve injury paralysis induced by local anesthetics is a rare complication with very few published cases Various techniques are available for diagnosing vocal cord paralysis, including, flexible fiberoptic laryngoscopy, videostrobolaryngoscopy and indirect laryngoscopy. However, these techniques are expensive and are often associated with pain and discomfort among patients. Considering these disadvantages, transcutaneous laryngeal ultrasound is an alternative imaging tool for vocal cord examination in patients undergoing thyroid and parathyroid surgery. We describe a case which was sonographically diagnosed a transient bilateral vocal cord paralysis after the local infiltration of 10mL of 2% mepivacaine administered for the revision of the surgical wound due to a subcutaneous hematoma that occurred after a subtotal parathyroidectomy.

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.

Vocal Cord Palsies Missed by Transcutaneous Laryngeal Ultrasound (TLUSG): Do They Experience Worse Outcomes?

INTRODUCTION

Transcutaneous laryngeal ultrasound (TLUSG) is an innovative, non-invasive tool in detecting post-thyroidectomy vocal cord palsy (VCP). However, TLUSG failed to detect about 6-15% laryngoscopic examination (LE)-confirmed VCP. It is unclear whether the outcome of patients with VCP missed by TLUSG [false negative (FN)] is different from those with VCP diagnosed by TLUSG [true positive (TP)]. Therefore, this study aimed to compare the clinical outcome and prognosis between patients with FN results and TP results.

METHODS

Over 46 months, all consecutive patients undergoing thyroidectomy or endocrine-related neck procedure were recruited. They underwent pre-operative and post-operative voice assessments on symptoms, voice-specific questionnaire [voice handicap index questionnaire (VHI-30)], TLUSG and LE. For patients with post-operative vocal cord palsy, reassessment LE would be arranged at second, fourth, sixth and twelfth months post-operatively until VCP recovered.

RESULTS

In total, 1196 patients, including 74 post-thyroidectomy VCP, were recruited. For those with assessable vocal cords (VC), 58 VCP were correctly diagnosed by TLUSG (TP) and 10 VCP were missed by TLUSG (FN). Sensitivity and specificity of detecting a VCP by TLUSG were 85.3% and 94.7%, respectively. VHI-30 score was significantly increased after operation in TP group [31 (range - 6-105), p < 0.001] but not in FN group [20 (14-99), p = 0.089]. Comparing to TP group, VCP recovered earlier (69 vs. 125 days, p < 0.001) and less patients suffered from permanent VCP in patients with FN results. (34.5% vs. 0.0%, p = 0.027).

CONCLUSION

The VCP missed by TLUSG had a milder course of disease. Early recovery of VC function and non-permanent palsy were expected.

Office-based laryngology: Technical and visual optimization by patient-positioning maneuvers

OBJECTIVE/HYPOTHESIS

To qualitatively and quantitatively assess the effect of discrete head postures/maneuvers during flexible laryngoscopy on visualization of specific anatomical structures within the laryngopharynx.

STUDY DESIGN

Prospective, observational study.

METHODS

Flexible laryngoscopy was performed on 18 sequential patients. Videos of the laryngopharynx were captured during the neutral head position and five discrete maneuvers: maximal sniffing, head extension, right turn, left turn, and chin down. Images were analyzed using ImageJ, and differences in the (normalized) anatomical areas of interest were examined with each maneuver (paired t test]. Covariates for surgeon, nostril, and gender were evaluated.

RESULTS

There was a significantly increased (P = 0.009) area of view of the anterior space (petiole of epiglottis/anterior laryngeal vestibule) with head extension. Right head turn led to a significantly increased view of the left pyriform sinus (P = 0.00001), whereas left head turn yielded an increased view of the right pyriform sinus (P = 0.0001). The right and left vocal fold/ventricle were better visualized during right head turn (with the scope traversing the right nostril) and left head turn (with the scope traversing the left nostril), respectively. Chin-down posture achieved a more distal view of the airway more frequently than the other maneuvers.

CONCLUSION

The anterior space (supraglottic larynx) may be best visualized and accessed with head extension. Right and left head turn improve visualization of the contralateral piriform sinus. Chin down provides improved airway visualization in a plurality of patients. Future studies examining maneuvers are warranted to create a catalog of validated techniques to optimize the efficacy of the office-based proceduralist.

LEVEL OF EVIDENCE

2 Laryngoscope, 129:330-334, 2019.

A Novel Lateral Approach to the Assessment of Vocal Cord Movement by Ultrasonography

BACKGROUND

Ultrasonography is a non-invasive technique that is commonly used by endocrinologists and endocrine surgeons to examine the thyroid region and could be useful for the assessment of vocal cord movement by these specialists. However, previous studies reported a low rate of successful visualization of vocal cord movement by ultrasonography. To address this issue, we devised a novel ultrasonographic procedure for assessing vocal cord movement indirectly by observing the arytenoid movement from a lateral view.

METHODS

Subjects were 188 individuals, including 23 patients with vocal cord paralysis and 13 with vocal cord paresis. We performed ultrasonographic assessment of vocal cord movement using two different procedures: the conventional middle transverse procedure and the novel lateral vertical procedure.

RESULTS

The rate of visualization of vocal cords with the middle transverse procedure was 70.2% and that of the arytenoid cartilage with the lateral vertical procedure was 98.4%. The lateral vertical procedure enabled visualization of all patients with vocal cord paresis/paralysis and detected all 23 patients with vocal paralysis; only one of 13 patients with vocal cord paresis was positively identified. The conventional procedure enabled visualization of 21 of 36 patients with vocal cord paresis/paralysis with high accuracy. There was no false-positive case in either procedure.

CONCLUSION

The proposed lateral vertical procedure improved the rate of visualization of vocal cord movement by ultrasonography, suggesting that it is a useful technique to screen for vocal cord paralysis by ultrasonography.

Sonographic Dynamic Description of the Laryngeal Tract: Definition of Quantitative Measures to Characterize Vocal Fold Motion and Estimation of Their Normal Values

Vocal fold motion was analyzed during free breathing using two-dimensional dynamic ultrasound imaging. Two cadavers were first analyzed to define easily identifiable landmarks. Motion of the laryngeal tract was then analyzed in an axial plane. Left and right arytenoids and thyroid cartilage were defined on images corresponding to abduction and adduction of the laryngeal tract. Associated area measurements were established for 50 healthy subjects. All area indices were significantly larger during abduction than adduction. Symmetry of motion was established by comparing each hemi-larynx, and mobility fractions were defined. Normal values of laryngeal motion during free breathing were thus established.

A Novel Gel Pad Laryngeal Ultrasound for Vocal Cord Evaluation

BACKGROUND

Laryngeal ultrasound (LUS) is a new method for vocal cord evaluation in patients with risk of vocal cord palsy (VCP). However, the previously described LUS reportedly had a high failure rate of vocal cord visualization in male patients. A novel gel pad LUS was devised to overcome the limitations of the previous method.

METHODS

A total of 482 (100 male) consecutive LUS and direct laryngoscopy examinations were performed in thyroidectomy and other neck surgery patients. The conventional LUS and gel pad LUS were used for all patients. Findings were independently cross-validated with direct laryngoscopy.

RESULTS

The conventional LUS and gel pad LUS methods had a 93.4% and 99.0% visualization rate, respectively, with a sensitivity of 98.0% for both methods, and a specificity of 99.7% and 99.8%, respectively. Among the 482 patients, 51 patients had VCP and 91 patients had diffuse thyroid cartilage calcification interrupting LUS.

CONCLUSION

The new gel pad LUS method significantly enhances the visualization of vocal cords in patients who have diffuse thyroid cartilage calcification interrupting LUS and, therefore, the overall efficacy of LUS as a perioperative diagnostic tool for VCP.

Lessons Learned After 1000 Cases of Transcutaneous Laryngeal Ultrasound (TLUSG) with Laryngoscopic Validation: Is There a Role of TLUSG in Patients Indicated for Laryngoscopic Examination Before Thyroidectomy?

INTRODUCTION

Patients with hoarseness of voice, previous neck operation, or suspicion of malignancy are at high risk of having pre-thyroidectomy vocal cord (VCP) palsy. Therefore, vocal cord (VC) functions should be evaluated before surgery. This study aimed to evaluate the accuracy of hoarseness, a voice-related questionnaire (Voice Handicap Index [VHI]-30), and transcutaneous laryngeal ultrasound (TLUSG) in diagnosing VCP, as well as the role of TLUSG in the evaluation of high-risk patients.

METHODS

A total of 1000 patients undergoing thyroidectomy or other endocrine-related neck procedures were prospectively included. Symptoms of hoarseness, the VHI-30 score, and TLUSG were evaluated. Validation laryngoscopies were performed by a separate endoscopist after performing TLUSG. All the assessments were performed one to seven days before surgery. The findings of hoarseness, the VHI-30 score, and TLUSG were correlated with laryngoscopic findings to evaluate the diagnostic accuracy.

RESULTS

Of 1000 patients, nine preoperative VCP were diagnosed with laryngoscopy. Sensitivity in detecting VCP by hoarseness, the VHI-30 score, and TLUSG were 33.3%, 62.5%, and 88.9%, respectively. A total of 342 patients were considered as high risk, and eight preoperative VCP were confirmed with laryngoscopy. Despite it not being possible to visualize the VCs in 26 (7.7%) patients, TLUSG had a higher accuracy in detecting VCP than the VHI-30 did (96.8% vs. 74.2%; p < 0.001). If patients had been selected who were unassessable or who had had VCP on assessment for confirmatory laryngoscopy, TLUSG saved more patients from laryngoscopic examinations than the VHI-30 did (87.7% vs. 71.3%; p < 0.001). A history of neck operation and suspicion of malignancy did not affect the assessment by TLUSG (p > 0.05).

CONCLUSION

TLUSG is a feasible, non-invasive, and sensitive tool in detecting VCP in high-risk patients. It has safely precluded 87.7% high-risk patients from laryngoscopy. TLUSG should be incorporated as a part of the ultrasound examination of the thyroid.