Comparison of ultrasound frequency in laryngeal ultrasound for vocal cord evaluation

Virtual Reality Helps Describe the Progression of Thyroid Cartilage Calcification

OBJECTIVES

Thyroid cartilage (TC) calcifications may impact surgical planning and clinical management. However, few studies to date have implemented virtual reality (VR) to evaluate these calcifications. This study assessed the feasibility of evaluating TC calcifications in various regions and measuring their volumes through VR models generated from computed tomography scans. We also investigated age and gender-related differences in calcification patterns.

METHODS

Ninety-two participants were categorized into younger, middle-aged, and older age groups. Calcification patterns (degree in Hounsfield units and volume of calcification in cm3) in different TC regions were identified by VR analysis, which enabled comparisons between age groups and genders.

RESULTS

Significant differences in calcification patterns were observed between males and females, particularly in the middle right, middle left, bottom left, and vertex regions. Age-related differences in the vertex region showed increased calcification in the older age group.

CONCLUSION

This study points to the contribution of VR in the evaluation of complex anatomical structures. The findings revealed significant gender and age patterns in TC calcification. These insights can inform surgical planning and highlight the potential of using VR to gain a better understanding of TC calcification clinically.

Can Transcutaneous Laryngeal Ultrasonography Systematically Quantify Vocal Fold Movement?-A Feasibility Study

OBJECTIVES

Several studies have assessed adult vocal fold movement using transcutaneous laryngeal ultrasonography (TLUSG) during the perioperative period of thyroidectomy. However, the movement was not objectively quantified. This study aimed to provide a feasible and objective method for assessing vocal fold movement using TLUSG.

STUDY DESIGN

Feasibility study.

METHODS

TLUSG was performed during calm breathing and breath-holding in healthy adult volunteers. The morphology and anatomy of the larynx were observed and measured using an ultrasonic self-contained measurement function. At the end of the calm inspiratory and breath-holding phases, vocal fold angle, vocal fold length, distance from vocal process to the midline, distance from anterior vocal commissure to arytenoid cartilage, distance from false vocal fold to the midline, and distance from the anterior horn of thyroid cartilage to false vocal fold were measured. Data were analyzed using a t test (significance <0.05).

RESULTS

The ultrasonic images were satisfactory in all 40 healthy adult volunteers (age 19-35 years; body mass index 18.55-23.93 kg/m2; 20 men and 20 women). There were no significant differences in all laryngeal parameters between the left and right sides in both phases (P > 0.05). Moreover, all differences in laryngeal parameters between the end of the calm inspiratory phase and the breath-holding phase were statistically significant (P < 0.05), regardless of sex.

CONCLUSION

The relevant positional parameters of the vocal fold, arytenoid cartilage, and false vocal fold and their differences before and after vocal fold movement in healthy adult volunteers can be obtained objectively using TLUSG.

ACR Appropriateness Criteria® Cranial Neuropathy: 2022 Update

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Feasibility and accuracy of laryngeal ultrasound for the assessment of vocal cord mobility in children

OBJECTIVE

Transcutaneous laryngeal ultrasonography has been utilized to document vocal cord mobility in the adult perioperative thyroidectomy setting with variable success. The aims of this study were to assess the feasibility of using transcutaneous ultrasound in vocal cord visualization in children, to determine the accuracy in detecting vocal cord immobility compare to flexible laryngoscopy, and to identify any barriers that may affect its utility.

METHODS

This is a prospective blinded-assessor study. Transcutaneous laryngeal ultrasound and flexible laryngoscopy were performed in two pediatric settings: perioperative thyroid surgery and inpatient consultation for airway, voice, or swallowing concerns. The video recordings of ultrasound and laryngoscopy were assessed by two fellowship-trained pediatric otolaryngologists independently.

RESULTS

A total of 83 paired laryngoscopy and ultrasound assessments were performed, 39 for perioperative thyroidectomy and 44 for inpatient consultation. The majority had normal vocal cord mobility (65/83, 78%), while 16 had unilateral cord palsy and 2 had bilateral palsy. The vocal cords were successfully visualized on ultrasound in 82/83 (99%) evaluations. Compared to gold standard laryngoscopy, the sensitivity for diagnosing vocal cord palsy on ultrasound was 53-83%, and the specificity was 97-98%. The sensitivity for detecting asymmetric vocal cord movement was 56-88%, and the specificity was 99%. The agreement between ultrasound and laryngoscopy diagnoses were 87-94% (κ = 0.58-0.83, moderate to near perfect agreement). The intra-rater agreement was 95-100% (κ = 0.64-1.0), and inter-rater agreement was 90% (κ = 0.66). Both subjects with bilateral vocal cord palsy had incorrect ultrasound diagnoses by both observers.

CONCLUSION

We were able to utilize transcutaneous laryngeal ultrasound to successfully visualize vocal cord mobility in almost all pediatric patients with a high degree of specificity. The modality has limitations in the assessment of bilateral vocal cord palsy, and its sensitivity was observer-dependent.

Using Intra-Operative Laryngeal Ultrasonography as a Real-Time Tool in Assessing Vocal Cord Function During Radiofrequency Ablation of the Thyroid Gland

BACKGROUND

Inadvertent injury of the recurrent laryngeal nerve can occur during radiofrequency ablation (RFA) of thyroid nodules. Methods to avoid permanent injury have not been described. Laryngeal ultrasonography (LUSG) can assess the function of vocal cords (VCs) in real time. The present study aimed to evaluate the feasibility and accuracy of LUSG in assessing real-time VC function during RFA of benign thyroid nodules.

METHODS

Consecutive patients undergoing RFA for benign thyroid nodules under local anesthesia were included. Spontaneous VC movements were checked with intra-operative LUSG (iLUSG) following each transverse ablation plane. In case of reduced VC movement, the ablation was stopped immediately. Post-ablation VC function was rechecked by LUSG on day-0 and flexible laryngoscopy (FL) on day-7. A concordance with day-0 LUSG or day-7 FL was a "true positive" or "true negative" depending on the presence or absence of VC palsy (VCP). Accuracy was calculated as the sum of all true positives and negatives divided by total nerves-at-risk.

RESULTS

Of 65 eligible patients, 56 (86.2%) were females. Twelve (18.5%) patients had bilateral lobe RFA, while 53 (81.5%) had unilateral RFA. The total number of nerves-at-risk was 77. Three unilateral VCPs (3.9%) were initially detected on iLUSG and confirmed by day-0 LUSG. All recovered fully within one week. The overall accuracy of iLUSG was 100%.

CONCLUSION

iLUSG is a highly accurate method that permits real-time feedback on the function of the VCs during RFA procedure. Real-time detection of VCP may prevent permanent injury. Methodological routine use of iLUSG is recommended during thyroid RFA.

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.

Intraoperative trans-laryngeal ultrasound (LUSG) of the vocal cord is a novel method of confirming the recurrent laryngeal nerve (RLN) integrity during thyroid and neck surgery

BACKGROUND

Eliciting a normal electromyography signal has been the usual method to confirm the functional integrity of the recurrent laryngeal nerve during intraoperative nerve monitoring. Given that oscillations of the vocal cord can be detected with trans-laryngeal ultrasound when the ipsilateral recurrent laryngeal nerve is stimulated with the endotracheal tube in situ, we aimed to compare the accuracy and cost of this novel method with the conventional electromyography method.

METHODS

Consecutive patients who underwent elective thyroid, parathyroid or neck dissection procedures were included. The NIM-Neuro 3.0 system was used. Endotracheal tube-based surface electrodes were utilized for electromyography signal recording. Standard anesthetic technique was adopted. Recurrent laryngeal nerve integrity was verified by both detection methods (laryngeal ultrasound and electromyography) independently. Vocal cord function was validated by flexible direct laryngoscopy postoperatively. For each method, concurrence with flexible direct laryngoscopy was defined as "true-positive" or "true-negative," based on the presence or absence of vocal cord paresis. Accuracy was calculated as the sum of all true positives and negatives divided by the total of nerves-at-risk. The cost of each method was calculated.

RESULTS

One hundred and four patients were eligible. Total number of nerves-at-risk was 155. Based on flexible direct laryngoscopy findings, the test sensitivity, specificity, positive predictive value, and negative predictive value of intraoperative laryngeal ultrasound were 75.0%, 99.3%, 85.7%, and 98.6%, respectively, while those of electromyography were 87.5%, 98.0%, 70.0%, and 99.3%, respectively. The prognostic accuracy in laryngeal ultrasound versus electromyography was comparable (98.1% vs 97.4%). The cost of the laryngeal ultrasound per operation was less than electromyography ($82 vs $454).

CONCLUSION

Laryngeal ultrasound has a similar detection accuracy to electromyography during intraoperative nerve monitoring. Apart from being a cheaper alternative, laryngeal ultrasound may be useful when there is unexplained loss of electromyography signals during surgery and may play a role in the intraoperative nerve monitoring troubleshooting algorithm.

A prospective study evaluating the feasibility and accuracy of very early postoperative translaryngeal ultrasonography in the assessment of vocal cord function after neck surgery

BACKGROUND

Early recognition of postoperative vocal cord palsy enhances postoperative care. Translaryngeal ultrasonography can assess vocal cord function accurately and noninvasively, but it is unclear whether it is feasible or accurate when done immediately after extubation in the recovery room owing to possible interference from laryngeal swelling. This study assessed the feasibility and accuracy of translaryngeal ultrasonography in this setting.

METHODS

Consecutive patients undergoing neck operations were subjected to translaryngeal ultrasonography and flexible direct laryngoscopy 1 day before and day 7 after thyroidectomy and parathyroidectomy. Translaryngeal ultrasonography was performed early in the recovery room immediately after extubation in the operating room. A standardized assessment protocol was used. Patient parameters were compared between those with assessable and unassessable vocal cords.

RESULTS

Sixty-five patients (91 recurrent laryngeal nerves-at-risk) were analyzed after excluding 2 male patients who failed preoperative translaryngeal ultrasonography. Fifty-six patients underwent thyroidectomy and 9 parathyroidectomy. The median age (range) was 57 (46-69); 44 (68%) were women. Sixty-one patients (94%) had assessable bilateral vocal cords on translaryngeal ultrasonography in the recovery room. Translaryngeal ultrasonography in the recovery room findings corresponded completely with day-7 findings on direct laryngoscopy. Long operative time was associated with nonassessable vocal cords on translaryngeal ultrasonography in the recovery room (P = .026).

CONCLUSION

Very early postoperative translaryngeal ultrasonography in the recovery room after neck surgery is highly feasible and accurate. Long operative time may hinder the use of translaryngeal ultrasonography in the recovery room.

Comparison of the vessel sealer Extend® with harmonic ACE® in robotic bilateral axillary-breast approach thyroid surgery

Background

Harmonic ACE^® (Harmonic) Curved Shears are frequently used for vessel sealing in patients undergoing robotic thyroidectomy. Unlike other robotic devices with articulation, the Harmonic device can only move in a straight-forward direction without articulation. The recently introduced Vessel Sealer Extend^® (VSE) provides bipolar sealing and cutting with articulation movement. This study compared the VSE and Harmonic devices in robotic bilateral axillary-breast approach (BABA) thyroid surgery.

Methods

From December 2018 to March 2019, 35 consecutive patients underwent robotic BABA thyroidectomy, 20 using the VSE and 15 using the Harmonic device. Patient characteristics, pathologic results, and clinical outcomes, including complications, were evaluated.

Results

The characteristics of patients in the two groups were similar. Surgical time from robot docking to completion of lobectomy was longer in the VSE than in the Harmonic group (45.00±9.52 vs. 39.72±12.76 min; P=0.170). The number of camera cleanings during lobectomy was significantly lower in the VSE group (0.55±0.51 vs. 1.93±1.71; P=0.002). Intraoperative blood loss (53.00±43.29 vs. 28.67±41.03 mL; P=0.102), hospital stay after surgery (3.55±0.95 vs. 3.67±0.90 days; P=0.715), and pain scores on the first (2.85±0.37 vs. 2.93±0.26; P=0.458) and second (2.55±0.51 vs. 2.60±0.51; P=0.775) postoperative days were similar in the VSE and Harmonic groups. No patient experienced vocal cord palsy or postoperative bleeding.

Conclusions

VSE can be safely applied to robotic BABA thyroid surgery.

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.

Assessing laryngeal function and hypersensitivity

The larynx is one of the most highly innervated organs in humans, adapted to simultaneously deliver several key respiratory functions including airway protection, swallowing and phonation. In some individuals the larynx can adopt a state that could be considered 'dysfunctional' or maladaptive; resulting in or contributing to a range of clinical disorders such as chronic refractory cough, inducible laryngeal obstruction (previously termed paradoxical vocal fold movement or vocal cord dysfunction), muscle tension dysphonia and globus pharyngeus. These disorders appear to display significant overlap in clinical symptomology and in many cases have features of concomitant or allied sensory dysfunction; often described as laryngeal hypersensitivity. The recognition and accurate assessment of both laryngeal dysfunction±hypersensitivity is important to ensure accurate diagnosis and effective delivery of targeted treatment and therapeutic monitoring. Accordingly, there is increasing in the methodologies proposed to assess laryngeal function. These range from simple questionnaires to targeted investigation(s), assessing both sensory function and the laryngeal motor response, under both resting and provoked situations. This review provides a brief overview of the current state of knowledge in the field of laryngeal dysfunction and hypersensitivity assessment.

The surgical management of primary hyperparathyroidism: an updated review

Patients with primary hyperparathyroidism often present clinically asymptomatic with various biochemical compositions of serum calcium, parathyroid hormone, vitamin D and urinary calcium. Understanding the subtle differences in clinical and biochemical presentations is key for timely diagnosis and referral to an experienced parathyroid surgeon. Surgery remains the only option for cure of primary hyperparathyroidism, which now favors a directed parathyroidectomy with intra-operative adjuncts. However it is important to understand and revise the surgical approach for patients with hereditary conditions or nonlocalizing studies. Revised guidelines from the Fourth International Workshop on the Management of Asymptomatic Primary Hyperparathyroidism in 2013 and the American Association of Endocrine Surgeons in 2016 are reviewed in this paper for an updated review of this condition.