Flexible Laryngoscopy: A Comparison of Fiber Optic and Distal Chip Technologies. Part 1: Vocal Fold Masses

Flexible Endoscopic Evaluation of Swallowing: A Proposed Checklist

PURPOSE

Flexible endoscopic evaluation of swallowing (FEES) is not only a well-recognized and ubiquitous tool in dysphagia research but also possesses features that make the assessment vulnerable to shortcomings in transparency and rigor in published literature. Therefore, FEES was considered an important addition to the Framework for RigOr aNd Transparency In REseaRch on Swallowing (FRONTIERS), a multisite collective effort to establish a tool for the critical appraisal of reporting in all forms of dysphagia and swallowing-related research on human subjects.

METHOD

From the FRONTIERS collective, a team of three clinician researchers completed a review of FEES-related literature to determine all components crucial for generalizable and reproducible reporting of FEES research. These components were developed and refined through an iterative process.

RESULTS

This review culminated in a 26-item series of "yes/no" questions, forming the FEES section of FRONTIERS. These questions are grouped into the following five components: (a) Equipment, (b) Rater(s), (c) Rating Process, (d) Outcome Metrics, and (e) Miscellaneous Factors.

CONCLUSION

The results of this review support that FEES possesses unique characteristics to other aspects of dysphagia research and is consequently a crucial addition to FRONTIERS to ensure that clinical researchers have access to critical appraisal of FEES-related research inquiry.

Clinical and Anatomical Variation During Assessment of Maximum Glottic Angle

INTRODUCTION

Quantitative measurement and analysis of glottic abduction is used to assess laryngeal function and success of interventions; however, the consistency of measurement over time has not been established. This study assesses the consistency of glottic abduction measurements across visits in healthy patients and anatomic factors impacting these measurements.

METHODS

Review of patients with two sequential flexible stroboscopic exams over seven months from 2019-2022. Images of maximal glottic abduction were captured and uploaded into and measured with ImageJ. Cadaver heads were used to assess the impact of visualization angles on glottic measurements with a monofilament inserted into the supraglottis of each cadaver as a point of reference. Comparisons were done with a paired T-test, T-test, or Mann-Whitney U test as appropriate.

RESULTS

Fifty-nine patients and twenty-six cadaveric exams were included. Absolute change in maximum glottic abduction angle (MGAA) was 6.90° (95% CI [5.36°, 8.42°]; p < 0.05). There were no significant differences in change in MGAA by gender or age. Twenty percent of patients had a change of at least 25% in their MGAA between visits. Absolute differences in glottic angle between nasal side for cadaveric measurements was 4.77 ± 4.59° (p < 0.005)-2.22° less than the change in MGAA seen over time (p = 0.185).

CONCLUSION

Maximal glottic abduction angles varied significantly between visits. Factors considered to be contributing to the differences include different viewing windows between examinations due to the position and angulation of the laryngoscope and changes in patient positioning, intra- and inter-rater variations in measurement, and patient effort.

LEVEL OF EVIDENCE

N/a Laryngoscope, 134:2793-2798, 2024.

Design and Usability of an Open-Source, Low-Cost Flexible Laryngoscope for Resource-Limited Settings

Importance

Endoscopes are paramount to the practice of otolaryngology. To provide physicians in low-middle-income countries with adequate tools to treat otolaryngologic problems, it is necessary to create a low-cost sustainable option.

Objective

To describe the design and usability of an open-source, low-cost flexible laryngoscope that addresses the lack of affordable and accessible methods for otolaryngologic visualization in resource-limited settings.

Design, Setting, and Participants

This quality improvement study used a mixed-methods approach, including a technical description of device design as well as quantitative and qualitative survey evaluation of device usability. Engineering involved device design, sourcing or manufacturing individual components, fabricating a prototype, and iterative testing. Key assumptions and needs for the device were identified in collaboration with otolaryngologists in Zimbabwe, and designed and simulated by biomedical engineers in a US university laboratory. Board-certified otolaryngologists at a single US university hospital trialed a completed prototype on simulated airways between May 2023 and June 2023.

Main Outcomes and Measures

Technical details on the design of the device are provided. Otolaryngologist gave feedback on device characteristics, maneuverability, and visualization using the System Usability Scale, a customized Likert-scale questionnaire (5-point scale), and semistructured interviews.

Results

A functional prototype meeting requirements was completed consisting of a distal-chip camera, spring bending tip, handle housing the control mechanism and electronics, and flexible polyether block amide-coated silicone sheath housing the camera and control wires; an external monitor provided real-time visualization and ability to store data. A total of 14 otolaryngologists participated in the device review. The mean (SD) System Usability Scale score was 88.93 (10.08), suggesting excellent usability. The device was rated highly for ease of set up, physical attributes, image quality, and functionality.

Conclusions and Relevance

This quality improvement study described the design of a novel open-source low-cost flexible laryngoscope that external review with otolaryngologists suggests was usable and feasible in various resource-limited environments. Future work is needed to translate the model into a clinical setting.

Sensitivity of Videolaryngostroboscopic Rating Tools to Differences in Dysphonia Severity

OBJECTIVES

This study evaluated the validity of two videolaryngostroboscopic (VLS) rating tools to detect differences in VLS ratings between normophonic speakers, mild, and moderate-severely dysphonic speakers.

METHODS

Sixteen rigid VLS exams were obtained from four normophonic controls and 12 speakers with dysphonia (8 =mild, 4 =moderate-severe) secondary to laryngeal pathology. Eight clinicians rated nine vibratory VLS parameters for each exam using both the Voice-vibratory Assessment of Laryngeal Imaging (VALI) tool and a 100 mm visual analog scales (VAS). Ratings obtained for both right and left vocal folds (eg, mucosal wave, amplitude of vibration, nonvibrating portion) were averaged. One rating of overall severity of laryngeal function using a 100 mm VAS also was obtained. ANOVAs were used to evaluate differences in VLS parameters between three speaker groups (normophonic, mildly dysphonic, moderate-severely dysphonic) using these two rating tools.

RESULTS

There were statistically significant differences between controls and moderate-severely dysphonic speakers and for all VLS parameters except phase symmetry (P < 0.05) for both VALI and VAS ratings. Differences between mildly dysphonic and moderate-severely dysphonic and speakers were observed for 4/6 VALI ratings (mucosal wave, nonvibratory portions, phase closure, and regularity) and 5/6 parameters (mucosal wave, amplitude of vibration, nonvibratory portions, phase closure, and regularity) for VAS ratings. Significant differences between controls and mildly dysphonic speakers were not observed for VLS parameter rated using the VALI. There were significant differences between controls and mildly dysphonic speakers for 3/6 parameters (mucosal wave, amplitude of vibration, nonvibratory portion) using a VAS. Ratings of overall severity of laryngeal function differed between all levels of dysphonia severity.

CONCLUSIONS

Significant differences in VLS ratings were observed for comparisons of normophonic and moderate-severely dysphonic speakers and mild to moderately dysphonic speakers using the VALI and the VAS. However, the VAS scale appeared to better differentiate differences in VLS measures between normophonic speakers and those with mild dysphonia. Future studies should consider rating scale sensitivity when VLS rating tools are selected for clinical and research purposes.

Edge Enhancement Optimization in Flexible Endoscopic Images to the Perception of Ear, Nose and Throat Professionals

OBJECTIVES

Digital endoscopes are connected to a video processor that applies various operations to process the image. One of those operations is edge enhancement that sharpens the image. The purpose of this study was to (1) quantify the level of edge enhancement, (2) measure the effect on sharpness and image noise, and (3) study the influence of edge enhancement on image quality perceived by ENT professionals.

METHODS

Three digital flexible endoscopic systems were included. The level of edge enhancement and the influence on sharpness and noise were measured in vitro, while systematically varying the levels of edge enhancement. In vivo images were captured at identical levels of one healthy larynx. Each series of in vivo images was presented to 39 ENT professionals according to a forced pairwise comparison test, to select the image with the best image quality for diagnostic purposes. The numbers of votes were converted to a psychometric scale of just noticeable differences (JND) according to the Thurstone V model.

RESULTS

The maximum level of edge enhancement varied per endoscopic system and ranged from 0.8 to 1.2. Edge enhancement increased sharpness and noise. Images with edge enhancement were unanimously preferred to images without edge enhancement. The quality difference with respect to zero edge enhancement reaches an optimum at levels between 0.7 and 0.9.

CONCLUSION

Edge enhancement has a major impact on sharpness, noise, and the resulting perceived image quality. We conclude that ENT professionals benefit from this video processing and should verify if their equipment is optimally configured.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:842-847, 2024.

The effect of the auditory signal on videolaryngostroboscopy ratings and interpretation

OBJECTIVE

The primary aim of this study was to examine the effect of the videolaryngostroboscopic auditory signal on videolaryngostroboscopy (VLS) ratings and interpretation in normophonic and dysphonic speakers.

STUDY DESIGN

Prospective repeated measures design METHOD: Eight speech-language pathologists evaluated rigid VLS exams obtained from 12 dysphonic speakers with vocal fold pathology and 4 normophonic speakers with normal VLS exams. VLS exams were evaluated with the auditory signal present and absent with a washout period between rating sessions. VLS measures were obtained using the Voice-vibratory Assessment of Laryngeal Imaging (VALI) and a 100mm visual analog scale (VAS). The effects of the auditory signal and its interaction with voice quality severity on 9 VLS ratings, diagnostic billing codes, and treatment recommendations were examined.

RESULTS

There was no effect of auditory information on VLS measures or overall severity of laryngeal function evaluated using the VAS (ps > 0.05). There was a main effect of auditory information and a significant interaction with voice quality severity for only one VLS measure (non-vibrating portion-left) evaluated using the VALI (P = 0.05). Post-hoc analysis for this rating showed significant increases (t-test adjusted P < 0.05) when voice quality severity was moderate-severe (M = 4.8%; SD = 1.65%) and auditory information was present. Agreement in individual clinician's selection of diagnostic codes (73%) and treatment recommendations (65.6%) when auditory cues were present and absent was moderate to high.

CONCLUSION

The presence of the videolaryngostroboscopic auditory signal had a minimal effect on VLS ratings, treatment recommendations, or diagnostic billing codes.

The Occurrence of Laryngeal Pathologies in a Treatment-Seeking Pediatric Population

OBJECTIVES

The purpose of this study was to 1) describe the age- and sex-specific occurrence of laryngeal pathologies in a treatment-seeking pediatric population in the voice unit of Ghent University Hospital, Belgium, and 2) describe this population in terms of vocal parameters, vocal complaints, influencing factors, and treatment history and recommendation.

STUDY DESIGN

Retrospective, observational study.

METHODS

All patient records were analyzed for children (0-18 years) who consulted the ear, nose, and throat department of Ghent University Hospital for the first time between July 2015 and June 2021 with complaints of dysphonia. In total, 103 children (66 males, 37 females) with a mean age of 10.01 years (SD: 3.4, range 3.93-17.96) were included in this study. Laryngeal pathology was diagnosed using a flexible videolaryngo(strobo)scopy. The influence of age and sex on laryngeal etiology (organic/functional voice disorder) was examined using a Welch-modified t test and a Fisher's exact test, respectively.

RESULTS

Organic lesions were observed in 77.7% of the participants, with vocal fold nodules (VFNs) being the most common diagnosis (66.0%). A functional voice disorder was diagnosed in 22.3% of the children. Children with a functional voice disorder are significantly older than children with an organic voice disorder. There was no statistically significant difference between males and females in laryngeal etiology. Mean dysphonia severity index was -2.7 (SD: 3.2, range -9.3 to +3.7), the mean acoustic voice quality index 4.70 (SD: 1.5, range 2.35-8.27), and the mean pediatric voice handicap index 29.8 (SD: 13.6, range 5-60). The occurrence of vocal misuse was mentioned in 80.6% of the patient records.

CONCLUSION

Organic voice disorders, especially VFNs, are predominant in treatment-seeking children with dysphonia. Functional voice disorders become more common with increasing age during childhood. A disordered vocal quality, reduced vocal capabilities and reduced voice-related quality of life were found.

Formation and Assessment of a Laryngology Pathology Video Atlas for Resident Education

OBJECTIVE

Conventional reference images of laryngeal pathologies may provide educational value for Otolaryngology-Head & Neck Surgery (OHNS) residents, but observing dynamic vocal fold function is critical for diagnosis. Our aim was to develop and validate a video atlas of laryngeal pathologies for resident education in OHNS.

DESIGN

A multi-institution, prospective case-control study.

SETTING/PARTICIPANTS

Ten videos showing 10 representative laryngeal pathologies were verified by two laryngologists. Six videos per category with kappa>0.8 were included in the video database. A collection of the videos was shown to a group of OHNS residents in a quiz fashion to determine if senior trainees would score higher than junior trainees. Another group of residents in OHNS was recruited and randomized to control or intervention. The control group was shown a quiz of 10 laryngeal videos at baseline and 24 weeks later. The intervention group was shown quizzes at baseline and every 6 weeks, ending at 24 weeks. Free-text diagnoses were scored for accuracy. Descriptive statistics, two-tailed tests, and analysis of covariance were performed.

RESULTS

Twenty-nine residents participated, with 14 (48.3%) randomized to control, and 15 (51.7%) to the intervention. The postgraduate year (PGY) level had a significant impact on diagnostic performance. PGY1 and 2 had a significantly lower score than PGY5 (P = 0.017 and P = 0.035, respectively). PGY3 and PGY4 scores were not statistically different from PGY5 scores. The mean score difference between groups decreases as the PGY level increases (mean difference between groups = 0.87, P = 0.153), but this was not significant.

CONCLUSIONS

The current study has created a validated collection of videos that are representative of common laryngeal pathologies and can be easily incorporated into resident video-based learning. Future directions include larger multi-site studies to further elucidate whether repeated viewing of this video atlas can improve OHNS resident laryngology knowledge.

Influence of edge enhancement applied in endoscopic systems on sharpness and noise

SIGNIFICANCE

Flexible endoscopes are essential for medical internal examinations. Digital endoscopes are connected to a video processor that can apply various operations to enhance the image. One of those operations is edge enhancement, which has a major impact on the perceived image quality by medical professionals. However, the specific methods and parameters of this operation are undisclosed and the arbitrary units to express the level of edge enhancement differ per video processor.

AIM

Objectively quantify the level of edge enhancement from the recorded images alone, and measure the effect on sharpness and noise

APPROACH

Edge enhancement was studied in four types of flexible digital ear nose and throat endoscopes. Measurements were performed using slanted edges and gray patches. The level of edge enhancement was determined by subtracting the step response of an image without edge enhancement from images with selected settings of edge enhancement and measuring the resulting peak-to-peak differences. These values were then normalized by the step size. Sharpness was characterized by observing the normalized modulation transfer function (MTF) and computing the spatial frequency at 50% MTF. The noise was measured on the gray patches and computed as a weighted sum of variances from the luminance and two chrominance channels of the pixel values.

RESULTS

The measured levels were consistent with the level set via the user interface on the video processor and varied typically from 0 to 1.3. Both sharpness and noise increase with larger levels of edge enhancement with factors of 3 and 4 respectively.

CONCLUSIONS

The presented method overcomes the issue of vendors expressing the level of edge enhancement each differently in arbitrary units. This allows us to compare the effects, and we can start exploring the relationship with the subjectively perceived image quality by medical professionals to find substantiated optimal settings.

Flexible Versus Rigid Laryngoscopy: A Prospective, Blinded Comparison of Image Quality

OBJECTIVE

To compare flexible distal-chip laryngoscopy (FDL) and rigid telescopic laryngoscopy (RTL) in image quality and diagnostic ability.

STUDY DESIGN

Prospective cohort study; blinded comparison.

METHODS

Eighteen normal adult subjects were recruited to undergo both FDL and RTL and normalized videos were recorded. Three blinded laryngologists compared the videos for color fidelity, illumination, resolution, and vascularity, and indicated superiority with FDL, RTL, or no difference. Raters also reported if an abnormality was seen and in which video it was better visualized. Videos for two subjects were repeated to assess intra-rater reliability, making 20 video comparisons across 3 raters for a total of 60 ratings. Differences in responses were analyzed via Mann-Whitney U and Pearson Χ². Inter-rater reliability was assessed via Fleiss' kappa, and intra-rater reliability was assessed via percent agreement.

RESULTS

RTL was rated superior in all categories of image quality (47 vs 5 vs 8, P < 0.01; 47 vs 7 vs 6, P < 0.01; 51 vs 5 vs 4, P<0.01; 44 vs 9 vs 7, P < 0.01, respectively). An abnormality was seen 33 times with both modalities and 6 times with RTL only. When seen with both modalities, visualization was superior in RTL compared with FDL (29 vs 4, P <0.01).

CONCLUSIONS

There was significant superiority of RTL in all categories of image quality, with slight inter-rater agreement for color fidelity, resolution, and vascularity. RTL was also significantly better for visualization of abnormalities. These findings suggest superior image quality in RTL compared with FDL, but further research is required to determine if this difference is clinically significant.

Application of a Computer Vision Tool for Automated Glottic Tracking to Vocal Fold Paralysis Patients

OBJECTIVES

(1) Demonstrate true vocal fold (TVF) tracking software (AGATI [Automated Glottic Action Tracking by artificial Intelligence]) as a quantitative assessment of unilateral vocal fold paralysis (UVFP) in a large patient cohort. (2) Correlate patient-reported metrics with AGATI measurements of TVF anterior glottic angles, before and after procedural intervention.

STUDY DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

METHODS

AGATI was used to analyze videolaryngoscopy from healthy adults (n = 72) and patients with UVFP (n = 70). Minimum, 3rd percentile, 97th percentile, and maximum anterior glottic angles (AGAs) were computed for each patient. In patients with UVFP, patient-reported outcomes (Voice Handicap Index 10, Dyspnea Index, and Eating Assessment Tool 10) were assessed, before and after procedural intervention (injection or medialization laryngoplasty). A receiver operating characteristic curve for the logistic fit of paralysis vs control group was used to determine AGA cutoff values for defining UVFP.

RESULTS

Mean (SD) 3rd percentile AGA (in degrees) was 2.67 (3.21) in control and 5.64 (5.42) in patients with UVFP (P < .001); mean (SD) 97th percentile AGA was 57.08 (11.14) in control and 42.59 (12.37) in patients with UVFP (P < .001). For patients with UVFP who underwent procedural intervention, the mean 97th percentile AGA decreased by 5 degrees from pre- to postprocedure (P = .026). The difference between the 97th and 3rd percentile AGA predicted UVFP with 77% sensitivity and 92% specificity (P < .0001). There was no correlation between AGA measurements and patient-reported outcome scores.

CONCLUSIONS

AGATI demonstrated a difference in AGA measurements between paralysis and control patients. AGATI can predict UVFP with 77% sensitivity and 92% specificity.

Cost-Effective Smartphone-Based Articulable Endoscope Systems for Developing Countries: Instrument Validation Study

Background

Endoscopes are widely used for visualizing the respiratory tract, urinary tract, uterus, and gastrointestinal tracts. Despite high demand, people in underdeveloped and developing countries cannot obtain proper access to endoscopy. Moreover, commercially available endoscopes are mostly nonarticulable as well as not actively controlled, limiting their use. Articulating endoscopes are required for some diagnosis procedures, due to their ability to image wide areas of internal organs. Furthermore, actively controlled articulating endoscopes are less likely to harm the lumen than rigid endoscopes because they can avoid contact with endothelial tissues.

Objective

The study aimed to demonstrate the feasibility and acceptability of smartphone-based wide-field articulable endoscope system for minimally invasive clinical applications in developing and less developed countries.

Methods

A thin articulable endoscope system that can be attached to and actively controlled by a smartphone was designed and constructed. The system consists of a flexible endoscopic probe with a continuum mechanism, 4 motor modules for articulation, a microprocessor for controlling the motor with a smartphone, and a homebuilt app for streaming, capturing, adjusting images and video, and controlling the motor module with a joystick-like user interface. The smartphone and motor module are connected via an integrated C-type On-The-Go (OTG) USB hub.

Results

We tested the device in several human-organ phantoms to evaluate the usability and utility of the smartphone-based articulating endoscope system. The resolution (960 × 720 pixels) of the device was found to be acceptable for medical diagnosis. The maximum bending angle of 110° was designed. The distance from the base of the articulating module to the tip of the endoscope was 45 mm. The angle of the virtual arc was 40.0°, for a curvature of 0.013. The finest articulation resolution was 8.9°. The articulating module succeeded in imaging all 8 octants of a spherical target, as well as all 4 quadrants of the indices marked in human phantoms.

Conclusions

The portable wide-field endoscope was successfully controlled using a smartphone, yielding clear images with a resolution of 960 × 720 pixels at realistic focal distances. Actively and precisely controlled articulating movements have resulted in minimally invasive monitoring in the narrow space of internal organs providing a wide-area view. We found our smartphone-based active articulated endoscope to be suitable for point-of-care applications in developing and less developed countries.

Detection of Aspiration, Penetration, and Pharyngeal Residue During Flexible Endoscopic Evaluation of Swallowing (FEES): Comparing the Effects of Color, Coating, and Opacity

The aim of this study was to assess the effects of color, coating, and opacity on the detection of aspiration, penetration, and residue during flexible endoscopic evaluations of swallowing (FEES). Thirty dysphagic adults underwent FEES while swallowing five 5 mL thin liquid boluses (1 × each, randomized): white water, blue water, white milk, blue milk, and barium water. To assess the effects of color, blue milk was compared to white milk. To assess the effects of coating, barium, white water, and white milk were compared to each other. To assess the effects of opacity, blue milk was compared to blue water. Videos were blindly analyzed and judged for the presence of pharyngeal residue, penetration, and aspiration. Repeated measures analyses were used to assess differences in the frequency of detection across bolus types. Pharyngeal residue was detected more frequently for liquids that were blue, had a coating effect, or were opaque (p < 0.05) when compared to liquids that were white, did not have a coating effect, or were translucent, respectively. Penetration and aspiration were detected more frequently for liquids that had a coating effect (p < 0.05), but not for liquids that were colored blue or opaque (p > 0.05). Coating appears to be the most important factor detecting thin liquid residue, penetration, and aspiration during FEES. Given these findings, standardized use of boluses that possess a coating effect (e.g., white-dyed water or barium) is highly recommended to enhance the sensitivity of identifying impairments in swallowing safety and efficiency during FEES.

An Open-Source Computer Vision Tool for Automated Vocal Fold Tracking From Videoendoscopy

OBJECTIVES

Contemporary clinical assessment of vocal fold adduction and abduction is qualitative and subjective. Herein is described a novel computer vision tool for automated quantitative tracking of vocal fold motion from videolaryngoscopy. The potential of this software as a diagnostic aid in unilateral vocal fold paralysis is demonstrated.

STUDY DESIGN

Case-control.

METHODS

A deep-learning algorithm was trained for vocal fold localization from videoendoscopy for automated frame-wise estimation of glottic opening angles. Algorithm accuracy was compared against manual expert markings. Maximum glottic opening angles between adults with normal movements (N = 20) and those with unilateral vocal fold paralysis (N = 20) were characterized.

RESULTS

Algorithm angle estimations demonstrated a correlation coefficient of 0.97 (P < .001) and mean absolute difference of 3.72° (standard deviation [SD], 3.49°) in comparison to manual expert markings. In comparison to those with normal movements, patients with unilateral vocal fold paralysis demonstrated significantly lower maximal glottic opening angles (mean 68.75° ± 11.82° vs. 49.44° ± 10.42°; difference, 19.31°; 95% confidence interval [CI] [12.17°-26.44°]; P < .001). Maximum opening angle less than 58.65° predicted unilateral vocal fold paralysis with a sensitivity of 0.85 and specificity of 0.85, with an area under the receiver operating characteristic curve of 0.888 (95% CI [0.784-0.991]; P < .001).

CONCLUSION

A user-friendly software tool for automated quantification of vocal fold movements from previously recorded videolaryngoscopy examinations is presented, termed automated glottic action tracking by artificial intelligence (AGATI). This tool may prove useful for diagnosis and outcomes tracking of vocal fold movement disorders.

LEVEL OF EVIDENCE

IV Laryngoscope, 131:E219-E225, 2021.

Laryngeal Image Processing of Vocal Folds Motion

This review provides a comprehensive compilation, from a digital image processing point of view of the most important techniques currently developed to characterize and quantify the vibration behaviour of the vocal folds, along with a detailed description of the laryngeal image modalities currently used in the clinic. The review presents an overview of the most significant glottal-gap segmentation and facilitative playbacks techniques used in the literature for the mentioned purpose, and shows the drawbacks and challenges that still remain unsolved to develop robust vocal folds vibration function analysis tools based on digital image processing.

Development of three-dimensional laryngostroboscopy for office-based laryngeal diagnostics and phonosurgical therapy

OBJECTIVE

To develop a three-dimensional (3D) laryngostroboscopic examination unit, compare the optic playback quality in relation to established 2D procedures, and report the first case series using 3D rigid laryngostroboscopy for diagnosis and management of laryngotracheal diseases.

STUDY DESIGN

Laboratory study, prospective case series.

METHODS

The optical efficacy of newly developed rigid 3D endoscopes was examined in a laboratory setting. Diagnostic suitability was investigated in 100 subjects (50 male, 50 female) receiving 2D high-definition (HD) and 3D laryngostroboscopy. Two of the subjects subsequently underwent 3D-assisted office-based transoral phonosurgery under local anesthesia. Main outcome measures were comparative visualization of laryngotracheal pathologies, influence on preoperative planning, and evaluation of prognostic factors for the outcome of phonosurgical interventions.

RESULTS

Three-dimensional endostroboscopic procedures were effectively optimized to establish an examination protocol for all-day clinical use. Office-based 3D laryngostroboscopy was successfully applied in subjects with normal anatomy (n = 10) and various laryngotracheal findings (n = 90). In comparison to 2D HD videolaryngostroboscopy, the 3D view offered enhanced visualization of laryngotracheal anatomy, with qualitatively improved depth perception and spatial representation. In organic pathologies, this resulted in a more precise indication of phonosurgical procedures, increased accuracy in surgical planning, facilitated office-based endoscopic surgery, and better evaluation of prognostic factors for the outcome of phonosurgical interventions.

CONCLUSION

Three-dimensional laryngostroboscopy proved to increase the understanding of functional and surgical anatomy. Its application has enormous potential for improving the diagnostic value of laryngoscopy, surgical precision in laryngotracheal interventions, tissue preservation, and methods of teaching.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2823-2831, 2018.

Digital Video Laryngoscopy and Flexible Endoscopic Biopsies as an Alternative Diagnostic Workup in Laryngopharyngeal Cancer: A Prospective Clinical Study

Objectives:

An office-based workup strategy for patients with laryngopharyngeal lesions suspicious for carcinoma is analyzed. The feasibility of office-based transnasal flexible endoscopic biopsies under local anesthesia and the impact on the diagnostic workup are evaluated.

Methods:

This study is a prospective analysis of patients with laryngeal, oropharyngeal, and hypopharyngeal lesions suspicious for carcinoma. One hundred eighty-eight participants were divided into 2 groups. The first group underwent an office-based biopsy procedure under local anesthesia using a flexible digital video laryngoscope with instrument channel (n = 53), and the second group underwent a biopsy procedure under general anesthesia using rigid laryngopharyngoscopy (n = 135).

Results:

Office-based flexible endoscopic biopsies were tolerated well, and there were no complications. These biopsies were 92.5% successful in acquiring a definitive diagnosis. Costs were reduced. Diagnostic workup time and time until start of therapy were reduced to 2 days and 27 days, respectively.

Conclusion:

Office-based biopsy under local anesthesia using flexible digital video laryngoscopy is safe, cost-effective, and successful in providing a histopathological diagnosis. It reduces the diagnostic workup time significantly in patients with laryngeal, oropharyngeal, and hypopharyngeal cancer, while also reducing the necessity to subsequently perform a rigid laryngopharyngoscopy under general anesthesia.

Recommended Protocols for Instrumental Assessment of Voice: American Speech-Language-Hearing Association Expert Panel to Develop a Protocol for Instrumental Assessment of Vocal Function

PURPOSE

The aim of this study was to recommend protocols for instrumental assessment of voice production in the areas of laryngeal endoscopic imaging, acoustic analyses, and aerodynamic procedures, which will (a) improve the evidence for voice assessment measures, (b) enable valid comparisons of assessment results within and across clients and facilities, and (c) facilitate the evaluation of treatment efficacy.

METHOD

Existing evidence was combined with expert consensus in areas with a lack of evidence. In addition, a survey of clinicians and a peer review of an initial version of the protocol via VoiceServe and the American Speech-Language-Hearing Association's Special Interest Group 3 (Voice and Voice Disorders) Community were used to create the recommendations for the final protocols.

RESULTS

The protocols include recommendations regarding technical specifications for data acquisition, voice and speech tasks, analysis methods, and reporting of results for instrumental evaluation of voice production in the areas of laryngeal endoscopic imaging, acoustics, and aerodynamics.

CONCLUSION

The recommended protocols for instrumental assessment of voice using laryngeal endoscopic imaging, acoustic, and aerodynamic methods will enable clinicians and researchers to collect a uniform set of valid and reliable measures that can be compared across assessments, clients, and facilities.

Safety of flexible endoscopic biopsy of the pharynx and larynx under topical anesthesia

Recent advancements in transnasal endoscopy enable a shift in diagnostic workup of lesions in the pharynx and larynx, from an examination with biopsy under general anesthesia to an office-based examination with flexible endoscopic biopsy under topical anesthesia. Procedural complications were evaluated to assess the safety of office-based flexible endoscopic biopsy in patients with benign and malignant laryngopharyngeal lesions. Patients who underwent flexible endoscopic biopsy from 2012 to 2016 were evaluated retrospectively. Complications were classified using the Clavien–Dindo classification of surgical complications. A total of 201 flexible endoscopic biopsies were performed in 187 patients. Two Clavien–Dindo grade I (laryngospasm and anterior epistaxis), one grade II (laryngeal bleeding), and one grade IIIb (laryngeal edema) complication were observed. The first complication was self-limiting and the other three required an intervention. All patients fully recovered without sequelae. Flexible endoscopic biopsy appears to be a safe office-based procedure for the diagnosis of benign and malignant laryngopharyngeal lesions.

Acoustic characteristics of different target vowels during the laryngeal telescopy

OBJECTIVE

The aim of this study was to investigate the acoustic characteristics of target vowels phonated in normal voice persons while performing laryngeal telescopy. The acoustic characteristics are compared to show the extent of possible difference to speculate their impact on phonation function.

METHODS

Thirty-four male subjects aged 20-39 years with normal voice were included in this study. The target vowels were /i/ and /ɛ/. Recording of voice samples was done under natural phonation and during laryngeal telescopy. The acoustic analysis included the parameters of fundamental frequency, jitter, shimmer and noise-to-harmonic ratio.

RESULTS

The sound of a target vowel /ɛ/ was perceived identical in more than 90% of the subjects by the examiner and speech language pathologist during the telescopy. Both /i/ and /ɛ/ sounds showed significant difference when compared with the results under natural phonation. There was no significant difference between /i/ and /ɛ/ during the telescopy.

CONCLUSION

The present study showed that change in target vowels during laryngeal telescopy makes no significant difference in the acoustic characteristics. The results may lead to the speculation that the phonation mechanism was not affected significantly by different vowels during the telescopy. This study may suggest that in the principle of comfortable phonation, introduction of the target vowels /i/ and /ɛ/ is practical.

Distal chip versus fiberoptic laryngoscopy using endoscopic sheaths: diagnostic accuracy and image quality

Laryngeal visualization is the hallmark in the diagnostic approach of laryngeal disease. In addition to fiberoptic techniques, digital distal chip technology has been developed to improve visualization. Endoscopic sheaths are used in daily clinical practice to prevent cross-contamination. The objective of the study was to evaluate diagnostic accuracy, image quality and interrater reliability of both flexible distal chip laryngoscopy (DCL) and flexible fiberoptic laryngoscopy (FOL) using contamination preventing endoscopic sheaths. In 53 cases both DCL and FOL images were collected during routine examination using endoscopic sheaths. All images were randomly shown to four experts in the field of laryngology and head and neck oncology. Observers were asked to choose a diagnosis, express their confidence level of that diagnosis and validate image quality: in this way 420 observations (four observers using two techniques) were analyzed. Accuracy in detecting laryngeal disease was 78 % (both DCL and FOL). Confidence level of diagnosis tended to be higher in DCL (p = 0.05). Image quality was validated better in DCL as compared to FOL (p < 0.05). Interrater agreement in identifying laryngeal disease was 1.5 times higher in DCL (κ = 0.44) as compared to FOL (κ = 0.29). In this study, reflecting daily clinical setting using sheathed endoscopes, DCL is identical to FOL regarding diagnostic accuracy, but DCL is superior to FOL in image quality and interrater reliability.

Value of high resolution ultrasonography in assessment of laryngeal lesions

OBJECTIVE

The aim of this study is to evaluate the value of high resolution ultrasonography (HRUS) in diagnosis of various laryngeal lesions which already diagnosed with rigid endoscopy.

STUDY DESIGN

Prospective study with control group.

PATIENTS AND METHODS

Sixty-six patients were suffering from throat symptoms and pre-examined by rigid endoscopy under local anesthesia and diagnosed to have a laryngeal lesion and 32 volunteers compose the control group. All 98 persons (patients and control groups) were examined by HRUS.

RESULTS

HRUS was helpful in describing various laryngeal lesions, vocal fold polyps (17) 25.7%, glottic cancer (6) 9.1%, epiglottic enlargement (2) 3.1% and one patient had laryngocele (1.5%). HRUS was highly significant in diagnosis of subglottic lesions (10) 15.2%. Also vocal fold mobility can be demonstrated by HRUS. While interarytenoid lesions (17) 25.8% and small laryngeal lesions as vocal fold nodules (13) 19.6% were difficult to be described.

CONCLUSION

Rigid endoscopy in laryngeal examination gives us large, bright image but it is difficult to diagnose patients with a sensitive gag reflex, patients with neck or jaw diseases or stridor and very difficult in infants and children. HRUS is an alternative method in diagnosis of some laryngeal lesions, and it is superior in the diagnosis of small subglottic lesions.

Accuracy of flexible versus rigid laryngoscopic photo-documentation in the diagnosis of early glottic cancer

Objective:

To compare the image quality provided by rigid laryngoscopes versus flexible distal-chip laryngoscopes when documenting the same laryngeal pathology.

Methods:

This paper reports a prospective single-blind study. Ten early stage glottic cancer cases were selected. Photographs of the pathologies were taken using both rigid and flexible distal-chip laryngoscopes (a total of 20 photographs). Nineteen clinicians were asked to review the laryngoscopic photographs; the clinicians were provided with a worksheet, which included questions regarding the clinical description, photograph quality and overall satisfaction with the images obtained. Clinicians' responses to the worksheet questions were then analysed.

Results:

The overall accuracy rate for lesion sidedness, anatomical sub-site involvement, anterior commissure involvement and tumour staging were 94.7 per cent, 46.6 per cent, 53.7 per cent and 47.1 per cent respectively. There were no statistically significant differences in terms of the accuracy rates, photograph quality or overall satisfaction with the photographs obtained by either modality.

Conclusion:

There were no statistically significant differences demonstrated in overall clinical accuracy or perceived image quality between the use of the rigid or flexible endoscopes when interpreting images of early glottic cancer.

Laryngovideostroboscopy in children--diagnostic possibilities and constraints

OBJECTIVE

The aim of this study was to report our experience with laryngovideostroboscopy (LVS) in consecutively examined children patients.

METHODS

The study included 150 children (2.5-14 years of age) diagnosed with dysphonia. Patients were divided into three age groups: group I - from 2.5 to 6 years of age (n = 31), group II - from 6 to 10 years of age (n = 73), and group III--from 10 to 14 years of age (n = 46). LVS was performed during the second visit. 3.5mg of dormicum were administered orally 30 min prior to LVS in all children from group I and in some patients belonging to group II. Local anesthesia of the pharyngeal mucosa was not needed in any case.

RESULTS

In nine out of 150 children, it was not possible to perform LVS during the first attempt. In eight of these children, the examination was performed successfully during another visit with satisfactory LVS images obtained. LVS revealed soft vocal fold nodules in 85 patients along with other organic changes found in five children: congenital laryngeal web (n = 1), vocal fold cysts (n = 3), and vocal fold paralysis (n = 1). Hyper-functional dysphonia was diagnosed in the remaining 60 subjects.

CONCLUSIONS

In order to perform successful LVS in children patient, the purpose and methodology of this examination should be explained to parents on the first visit whereas an attempt to perform LVS should be undertaken during the second visit. Oral administration of dormicum 30min prior to the examination is advisable, particularly in younger children, and allows us to avoid the use of local anesthetics.