Effects of thyroplasty type I on vocal fold vibration

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.

Quantitative Evaluation of Vocal Bowing Following Bilateral Thyroplasty in Age-Related Vocal Atrophy

OBJECTIVE

Age-related vocal atrophy (ARVA) is associated with vocal fold bowing, persistent glottal gap during phonation, and dysphonia. Bilateral medialization thyroplasty is sometimes performed in patients with ARVA to improve vocal fold closure and voice. We set out to quantify stroboscopic changes in vocal fold bowing, glottal closure, and abduction angle following bilateral thyroplasty and determine how these changes affect voice quality among patients with ARVA.

METHODS

Fifteen individuals with ARVA who underwent bilateral medialization thyroplasty were included in this study. Two independent investigators calculated bowing index (BI), normalized glottal gap area (NGGA), and maximum abduction angle from laryngostroboscopic exams using ImageJ™. Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) and patient-reported measures were collected before and after thyroplasty.

RESULTS

Thyroplasty resulted in a 10-point improvement in overall CAPE-V (Mean dif -10; 95% CI -17, -3.3, p < 0.01) and VHI-10 (mean dif -3.8; 95% CI -9.8, 2.3, p = 0.19, n = 8). NGGA and BI significantly decreased following surgery (mean dif -78; 95% CI -155, -1.5, p = 0.05; and mean dif -2.1; 95% CI -2.4, -0.84, p < 0.01, respectively). BI correlated with CAPE-V scores (r = 0.66, 95% CI 0.22, 0.87, p < 0.01). When considering the normalized combined contributions of both NGGA and BI, there was a stronger correlation in CAPE-V scores (r = 0.87, 95% CI 0.50, 0.97, p < 0.01) compared with either measure alone.

CONCLUSIONS

Thyroplasty resulted in a decrease in vocal fold bowing, glottal gap area, and CAPE-V scores in patients with ARVA. Correction of vocal bowing and glottal gap, following bilateral thyroplasty, improved voice measures following surgery. Quantitative evaluation of vocal fold morphology may be valuable when assessing the severity and treatment-response in patients with ARVA following bilateral thyroplasty. Laryngoscope, 134:835-841, 2024.

Excised human larynx in N-vinyl-2-pyrrolidone-embalmed cadavers can produce voiced sound by pliable vocal fold vibration

Tissue-hardening effect and health-hazard issue of formaldehyde (FA) have long been a great disadvantage of this conventional fixative in anatomical research. We recently developed a FA-free embalming method for cadavers which utilizes N-vinyl-2-pyrrolidone (NVP) and enables assessment of motion kinetics by maintaining the softness of embalmed tissue. By assessing the feasibility of NVP-embalmed tissue to mimic vocalization, this study aimed to prove the potential of embalmed cadavers, which have previously been used only for the understanding of anatomical morphology, for the assessment of precise motion physiology in the human body. Ten cadavers embalmed in NVP (n = 6) and FA (n = 4) were incorporated in this study. Excised larynges underwent experimental phonation to mimic vocalization with fast and pliable vibration of vocal folds. High-speed digital imaging was utilized for the assessment of vocal fold vibration. Furthermore, acoustic analysis of the voiced sound, and reproducibility examination were also performed. Regular vocal fold vibrations successfully produced voiced sounds during experimental phonation using NVP-embalmed larynges. The vibratory frequency, vibration amplitude, and stretch rate of the vocal folds were comparable to those of living humans. Six months after the first experiment, the vocal parameters were reproduced, to suggest the long-term preservation potential of our NVP-embalming technique. On the other hand, neither voiced sound nor vocal fold vibration were observed in FA-embalmed larynges. This novel embalming technique could pioneer the next era to utilize embalmed cadavers for the examination of motion physiology in the human body.

A computational framework for patient-specific surgical planning of type 1 thyroplasty

A computational framework is proposed for virtual optimization of implant configurations of type 1 thyroplasty based on patient-specific laryngeal structures reconstructed from MRI images. Through integration of a muscle mechanics-based laryngeal posturing model, a flow-structure-acoustics interaction voice production model, a real-coded genetic algorithm, and virtual implant insertion, the framework acquires the implant configuration that achieves the optimal acoustic objectives. The framework is showcased by successfully optimizing an implant that restores acoustic features of a diseased voice resulted from unilateral vocal fold paralysis (UVFP) in producing a sustained vowel utterance. The sound intensity is improved from 62 dB (UVFP) to 81 dB (post-correction).

Laryngeal stroboscopy-Normative values for amplitude, open quotient, asymmetry and phase difference in young adults

OBJECTIVE

To provide the normative values for laryngeal stroboscopy (LS) concerning amplitude, open quotient, asymmetry and phase difference in healthy, young subjects.

STUDY DESIGN

Prospective case-control study.

SETTING

Patients treated at a single institute.

METHODS

A total of 68 healthy subjects were included in the study (35 women, 33 men), aged 18-35 years. After obtaining LS recordings, image processing was performed to attain parameters of vocal fold vibration.

RESULTS

In women, the location of the maximum vibration amplitude is approximately in the 1/3 posterior part of the glottis, while in men, the location is moved to the glottis centre. In males, the relative amplitude vibration of the vocal folds in the 1/3 anterior part of the glottis was significantly higher than in females (P = 0.029). Women showed significantly higher open quotients (OQ) at the posterior part of the glottis than the male subjects (P < 0.001) and men presented significantly higher OQ at the anterior part of the glottis than the females (P < 0.001). The average OQ values for both sexes were almost the same. Females showed significantly higher relative glottal gap area (P = 0.044). Women presented a significantly lower amplitude asymmetry than men (P = 0.002). The weighted absolute left-right phase difference reached up to 24° and remained insignificantly higher in the men than the women (P = 0.142).

CONCLUSIONS

The study provides normative values for LS in young adults for the measurement of therapy outcomes in patients with voice disorders and realisation of evidence-based medicine. The LS parametrisation is easy to perform in clinical practice.

Influence of Left-Right Asymmetries on Voice Quality in Simulated Paramedian Vocal Fold Paralysis

PURPOSE

The purpose of this study was to determine the vocal fold structural and vibratory symmetries that are important to vocal function and voice quality in a simulated paramedian vocal fold paralysis.

METHOD

A computational kinematic speech production model was used to simulate an exemplar "voice" on the basis of asymmetric settings of parameters controlling glottal configuration. These parameters were then altered individually to determine their effect on maximum flow declination rate, spectral slope, cepstral peak prominence, harmonics-to-noise ratio, and perceived voice quality.

RESULTS

Asymmetry of each of the 5 vocal fold parameters influenced vocal function and voice quality; measured change was greatest for adduction and bulging. Increasing the symmetry of all parameters improved voice, and the best voice occurred with overcorrection of adduction, followed by bulging, nodal point ratio, starting phase, and amplitude of vibration.

CONCLUSIONS

Although vocal process adduction and edge bulging asymmetries are most influential in voice quality for simulated vocal fold motion impairment, amplitude of vibration and starting phase asymmetries are also perceptually important. These findings are consistent with the current surgical approach to vocal fold motion impairment, where goals include medializing the vocal process and straightening concave edges. The results also explain many of the residual postoperative voice limitations.

Using peak direct subglottic pressure level as an objective measure during medialization thyroplasty: a prospective study

Type I medialization thyroplasty (MT) was introduced by Isshiki more than 40 years ago. It is one of the most widely used surgical options to correct glottic insufficiency. Intraoperatively, the surgeon relies solely on perceptual subjective measures to help to achieve an optimal glottic closure by bringing the affected vocal fold closer to the midline in order to close the glottic gap. One of the challenges of MT is the persistence of symptoms due to incorrect choice of implant size. As of now, no standard objective measure is being used to determine the optimal implant size needed to achieve the glottic closure required. Peak direct subglottic pressure (PDSGP) is one of the aerodynamic objective measurements of vocal efficiency that significantly increases in cases of glottic insufficiency. It is easily measured during MT by inserting a catheter through the cricothyroid membrane. A prospective study was carried out on patients undergoing MT using the Montgomery Implant(®). Choice of implant size was carried out based on the standard perceptual subjective assessment by the operating surgeon and was based on degree of glottic closure and voice quality. PDSGP was recorded for each implant size and then we tested the agreement between the chosen implant size and the lowest PDSGP. The agreement between the implant size of choice and the lowest PDSGP recorded was 62.5 % [CI 44-79 %]. PDSGP was easy to measure and resulted in no complications. PDSGP is a useful tool that could assist in the choice of the correct implant size needed during MT.

LEVEL OF EVIDENCE

4.

A Preliminary Quantitative Comparison of Vibratory Amplitude Using Rigid and Flexible Stroboscopic Assessment

STUDY OBJECTIVE

The purpose of this study was to establish preliminary, quantitative data on amplitude of vibration during stroboscopic assessment in healthy speakers with normal voice characteristics. Amplitude of vocal fold vibration is a core physiological parameter used in diagnosing voice disorders, yet quantitative data are lacking to guide the determination of what constitutes normal vibratory amplitude.

METHODS/STUDY DESIGN

Eleven participants were assessed during sustained vowel production using rigid and flexible endoscopy with stroboscopy. Still images were extracted from digital recordings of a sustained /i/ produced at a comfortable pitch and loudness, with F0 controlled so that levels were within ±15% of each participant's comfortable mean level as determined from connected speech. Glottal width (GW), true vocal fold (TVF) length, and TVF width were measured from still frames representing the maximum open phase of the vibratory cycle. To control for anatomic and magnification differences across participants, GW was normalized to TVF length. GW as a ratio of TVF width was also computed for comparison with prior studies.

RESULTS

Mean values and standard deviations were computed for the normalized measures. Paired t tests showed no significant differences between rigid and flexible endoscopy methods. Interrater and intrarater reliability values for raw measurements were found to be high (0.89-0.99).

CONCLUSIONS

These preliminary quantitative data may be helpful in determining normality or abnormality of vocal fold vibration. Results indicate that quantified amplitude of vibration is similar between endoscopic methods, a clinically relevant finding for individuals performing and interpreting stroboscopic assessments.

Correlating voice handicap index and quantitative videostroboscopy following injection laryngoplasty for unilateral vocal paralysis

OBJECTIVE

1) Determine the correlation between voice handicap index and quantitative videostroboscopy for patients undergoing injection laryngoplasty for unilateral vocal paralysis; 2) assess which videostroboscopy measurements correlate best with voice handicap index in patients demonstrating progressive improvement beyond six months following injection laryngoplasty.

STUDY DESIGN

Case series with chart review.

SETTING

Patients undergoing outpatient injection laryngoplasty with hyaluronic acid between 2005 and 2007.

SUBJECTS AND METHODS

Twenty-eight patients were assessed preoperatively and postoperatively using voice handicap index and videostroboscopy. Various videostroboscopy measurements were quantified: glottic open area (ratio of open to total glottic area during closed phase of phonation), glottic closed phase (frame ratio of closed phase to total glottic cycle), supraglottic compression (percent encroachment of supraglottis onto best-fit ellipse around glottis), wave amplitude (difference in glottic open area between open and closed phases), and wave duration (number of frames per glottic cycle). Correlation coefficients were calculated using Spearman's r.

RESULTS

One hundred seventeen separate recordings were analyzed. Correlation coefficients between voice handicap index (normalized to preoperative values) and glottic closed phase showed moderate-strong correlation (r = -0.733, P < 0.001), while glottic open area and wave duration showed weak-moderate correlation (r = 0.465, P < 0.001 and r = -0.404, P < 0.001 respectively). Other parameters showed poor correlation. A subset of 25 recordings from eight patients with progressive voice handicap index improvement beyond six months showed highest correlation with supraglottic compression (r = 0.504, P < 0.05).

CONCLUSION

Voice handicap index correlates best with glottic closed phase, suggesting duration of vocal fold closure during the glottic cycle best represents patients' subjective outcome post-procedure. Progressive improvement in voice handicap index beyond six months may relate to gradual reduction in compensatory supraglottic compression, with moderate correlation.

Article Commentary: Shortfalls of the American Academy of Otolaryngology—Head and Neck Surgery's Clinical practice guideline: Hoarseness (Dysphonia)

The Clinical Practice Guideline (CPG) on hoarseness (dysphonia) has several shortcomings that undermine its initial intent to improve the care of patients with dysphonia. The purpose of this document is to identify and comment on those shortcomings. The guideline authors made curious and unsupported policy recommendations in some areas, such as the recommendation for performance of laryngoscopy for hoarseness. For example, the guideline provides a three-month allowance for patients with voice change prior to examination of the larynx, which is a marked change from prior American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) documents suggesting laryngoscopy after two to four weeks of dysphonia and poses a health risk to patients with dysphonia without an established diagnosis. We believe the use of laryngoscopy for the evaluation is dysphonia is primal, plays a vital role in the care of our patients, and should be strongly advocated by the CPG. A significant challenge of the CPG is rooted in its basis on a symptom as opposed to a diagnosis. The decision to confuse the difference between a symptom (hoarseness) and a diagnosis leads to several misleading statements and recommendations. Finally, problems with insufficient peer review and ineffective processes in the guideline's development are discussed.

© 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Multiparameter analysis of titanium vocal fold medializing implant in an excised larynx model

OBJECTIVES

We evaluated the efficacy of the titanium vocal fold medializing implant (TVFMI) for the treatment of unilateral vocal fold paralysis (UVFP) on the basis of acoustic, aerodynamic, and mucosal wave measurements in an excised larynx setup.

METHODS

Measurements were recorded on 8 excised canine larynges with simulated UVFP before and after medialization with a TVFMI.

RESULTS

The phonation threshold flow (p < 0.001) and phonation threshold power (p = 0.008) decreased significantly after medialization. The phonation threshold pressure also decreased, but this difference was not significant (p = 0.081). Jitter (p = 0.005) and shimmer (p = 0.034) decreased significantly after medialization. The signal-to-noise ratio increased significantly (p = 0.05). Differences in mucosal wave characteristics were discernible but not significant. The phase difference between the normal and paralyzed vocal folds (p = 0.15) and the amplitude of the paralyzed vocal fold (p = 0.78) decreased. The glottal gap decreased significantly (p = 0.004).

CONCLUSIONS

The TVFMI was effective in achieving vocal fold medialization, improving vocal aerodynamic and acoustic characteristics of phonation significantly and mucosal wave characteristics discernibly. This study provides objective, quantitative support for the use of the TVFMI in improving vocal function in patients with UVFP.

Injection Versus Medialization Laryngoplasty for the Treatment of Unilateral Vocal Fold Paralysis

OBJECTIVE/HYPOTHESIS

To determine whether injection laryngoplasty or medialization laryngoplasty is more effective in the treatment of unilateral vocal fold paralysis.

STUDY DESIGN

A retrospective study of patients with unilateral vocal fold paralysis who underwent either injection or medialization laryngoplasty at the University of Arkansas for Medical Sciences between July 29, 2003 and March 8, 2005.

METHODS

The data analyzed included patient characteristics and type of intervention, along with the pretreatment and posttreatment voice parameters of videostrobolaryngoscopy, perceptual analysis, and patients' subjective voice assessment.

RESULTS

Nineteen patients were evaluated. The average time from intervention to posttreatment evaluation was 3 (range, 1-9) months. Improvements were demonstrated in all three voice parameters in both the injection and the medialization groups. No significant differences were found in the degree of improvement between the two groups. Videostrobolaryngoscopy and the perceptual analysis, both rated by the authors, correlated well with each other, but they both correlated poorly with the patients' subjective voice analysis.

CONCLUSIONS

Injection and medialization laryngoplasty were comparable in their improvement of subjective and objective voice outcomes. Both treatment modalities should be included in the otolaryngologist's armamentarium for managing unilateral vocal fold paralysis.

Voice Surgery

There have been many advances in microsurgery for voice professionals over the last three decades. Driven by a greater understanding of the anatomy and physiology of phonation, most of the advances provide greater surgical precision through improved exposure and more delicate instrumentation. Laryngologists who perform laryngoscopic surgery should be familiar with the current state-of-the-art and should use the latest techniques and technology for all voice patients and particularly for voice professionals. Video procedures for surgical management of voice disorders accompany this content online.

Aerodynamics, voice quality, and laryngeal image analysis of normal and pathologic voices

PURPOSE OF REVIEW

The purpose of this review is to describe examinations of phonatory function and their relation to image analysis of the unilaterally immobile larynx. Special emphasis was placed on image analysis using three-dimensional endoscopic images produced from CT scans.

RECENT FINDINGS

Developments in modern image processing technique have led to the quantification of various aspects of vocal fold vibration. Stroboscopic images of the vocal fold were digitized and, subsequently, the glottal gap area, amplitude, and degree of bowing were analyzed quantitatively in relation to phonatory function. Vocal fold vibration was observed with the aid of videokymography, during which images from a single transverse line can be recorded. Successive line images were shown in real time on a monitor, with the time dimension displayed in the vertical direction. This system enabled the assessment of left-right asymmetries, open quotient, propagation of mucosal waves, and forth. Three-dimensional endoscopic images derived from multislice CT scans provided a novel method for evaluating morphologic characteristics of the laryngeal lumen in relation to phonatory function. The combination of three-dimensional endoscopy and coronal reconstructed images supplemented stroboscopic findings exemplified by differences in vertical position and thickness between the vocal folds.

SUMMARY

Depth information about the vocal fold as well as the presence of paradoxic movement of the affected vocal fold and overadduction of the healthy vocal fold during phonation should be taken into account when surgical intervention to improve hoarseness resulting from unilateral vocal fold immobility is performed. Phonatory function tests, videostroboscopy, and laryngeal image analysis are prerequisites to achieving this goal.

Early results of transcutaneous injection laryngoplasty with micronized acellular dermis versus type-I thyroplasty for glottic incompetence dysphonia due to unilateral vocal fold paralysis

Medialization thyroplasty (type I) has become the gold standard to improve glottic closure due to unilateral vocal fold paralysis. A newer injection method utilizing homologous collagen from cadaveric human tissue has been described as an attractive alternative as no donor site is required, there is a very low risk of hypersensitivity, and the intact, acellular collagen fibers may suffer a reduced long-term reabsorption rate. Preliminary results on eight patients comparing presurgical and postsurgical parameters (perceptual, stroboscopic, acoustic, and aerodynamic) revealed comparable results when compared with a control group of individuals, age- and sex-matched, that had undergone standard medialization thyroplasty (type I). Further study is needed to assess the long-term results with this minimally invasive method of vocal fold medialization.

Functional results after external vocal fold medialization thyroplasty with the titanium vocal fold medialization implant

OBJECTIVES/HYPOTHESIS

A persistent insufficiency of glottal closure is mostly a consequence of a unilateral vocal fold movement impairment. It can also be caused by vocal fold atrophy or scarring processes with regular bilateral respiratory vocal fold function. Because of consequential voice, breathing, and swallowing impairments, a functional surgical treatment is required. The goal of the study was to outline the functional results after medialization thyroplasty with the titanium vocal fold medialization implant according to Friedrich.

METHODS

In the period of 1999 to 2001, an external vocal fold medialization using the titanium implant was performed on 28 patients (12 women and 16 men). The patients were in the age range of 19 to 84 years. Twenty-two patients had a paralysis of the left-side vocal fold, and six patients, of the right-side vocal fold. Detailed functional examinations were executed on all patients before and after the surgery: perceptive voice sound analysis according to the "roughness, breathiness, and hoarseness" method, judgment of the s/z ratio and voice dysfunction index, voice range profile measurements, videostroboscopy, and pulmonary function tests. In case of dysphagia/aspiration, videofluoroscopy of swallowing was also performed. The respective data were statistically analyzed (paired t test, Wilcoxon-test).

RESULTS

All patients reported on improvement of voice, swallowing, and breathing functions postoperatively. Videostroboscopy revealed an almost complete glottal closure after surgery in all of the patients. All voice-related parameters showed a significant improvement. An increase of the laryngeal resistance by the medialization procedure could be excluded by analysis of the pulmonary function test.

CONCLUSIONS

The results confirm the external medialization of the vocal folds as an adequate method in the therapy of voice, swallowing, and breathing impairment attributable to an insufficient glottal closure. The titanium implant offers, apart from good tissue tolerability, the advantage of an easy, time-saving, and individually adjustable application during the operation.

A new paramedian approach to arytenoid adduction and strap muscle transposition for vocal fold medialization

OBJECTIVE

To develop a prosthesis-free medialization laryngoplasty for the treatment of glottal incompetence.

STUDY DESIGN

Twenty-two consecutive patients with glottal incompetence underwent vocal fold medialization using a new paramedian approach to arytenoid adduction and/or strap muscle transposition.

METHODS

Under local anesthesia, the thyroid lamina on the involved side was parasagittally separated 5 mm off the midline. The inner perichondrium was carefully freed from the overlying thyroid cartilage. After dividing the thyrohyoid and cricothyroid membranes, the lamina was retracted laterally, the inner perichondrium was opened, and the lateral cricoarytenoid muscle identified. Tracing the muscle fibers posterosuperiorly, the muscular process of the arytenoid was identified. A 2-0 or 3-0 Prolene suture was placed through the muscular process and tied to the cricoid cartilage at the origin of the lateral cricoarytenoid muscle. A bipedicled strap muscle flap was then transposed into the space between the lamina and the inner perichondrium and the thyroid cartilages sutured back into place. Pre- and postoperative voice evaluations measured mean fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, and maximal phonation time, as well as assessments of voice quality.

RESULTS

Vocal improvement was obtained in 95% (21 of 22) of patients. There was a significant improvement (P <.05) in all parameters except shimmer. No major complications were noted in any patient, except for dyspnea in one patient resulting from arytenoid overrotation.

CONCLUSION

The results suggest that a paramedian approach to arytenoid adduction combined with strap muscle transposition is a safe and effective method for treating glottal incompetence, particularly in patients with unilateral paralytic dysphonia.