Design of a Mechanical Larynx With Agarose as a Soft Tissue Substitute for Vocal Fold Applications

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
J. Q. Choo ◽  
D. P. C. Lau ◽  
C. K. Chui ◽  
T. Yang ◽  
C. B. Chng ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Vocal Fold ◽  
Computational Models ◽  
Wound Closure ◽  
Lateral Expansion ◽  
Wound Closure Techniques ◽  
Vocal Fold Vibration ◽  
Flow Channels ◽  
Superior Surface ◽  
Biological Soft Tissue

Mechanical and computational models consisting of flow channels with convergent and oscillating constrictions have been applied to study the dynamics of human vocal fold vibration. To the best of our knowledge, no mechanical model has been studied using a material substitute with similar physical properties to the human vocal fold for surgical experimentation. In this study, we design and develop a mechanical larynx with agarose as a vocal fold substitute, and assess its suitability for surgical experimentation. Agarose is selected as a substitute for the vocal fold as it exhibits similar nonlinear hyperelastic characteristics to biological soft tissue. Through uniaxial compression and extension tests, we determined that agarose of 0.375% concentration most closely resembles the vocal fold mucosa and ligament of a 20-year old male for small tensile strain with an R2 value of 0.9634 and root mean square error of 344.05±39.84 Pa. Incisions of 10 mm lengthwise and 3 mm in depth were created parallel to the medial edge on the superior surface of agar phantom. These were subjected to vibrations of 80, 130, and 180 Hz, at constant amplitude of 0.9 mm over a period of 10 min each in the mechanical larynx model. Lateral expansion of the incision was observed to be most significant for the lower frequency of 80 Hz. This model serves as a basis for future assessments of wound closure techniques during microsurgery to the vocal fold.

Empirical Eigenfunctions and Medial Surface Dynamics of a Human Vocal Fold

2005 ◽  
Vol 44 (03) ◽  
pp. 384-391 ◽  
Author(s):  
N. Tayama ◽  
D. A. Berry ◽  
M. Döllinger
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Computational Models ◽  
Imaging System ◽  
Vocal Folds ◽  
Sustained Oscillation ◽  
Medial Surface ◽  
Physical Mechanisms ◽  
Vocal Fold Vibration ◽  
Modes Of Vibration

Summary Objectives: The purpose of this investigation was to use an excised human larynx to substantiate physical mechanisms of sustained vocal fold oscillation over a variety of phonatory conditions. During sustained, flow-induced oscillation, dynamical data was collected from the medial surface of the vocal fold. The method of Empirical Eigenfunctions was used to analyze the data and to probe physical mechanisms of sustained oscillation. Methods: Thirty microsutures were mounted on the medial margin of a human vocal fold. Across five distinct phonatory conditions, the vocal fold was set into oscillation and imaged with a high-speed digital imaging system. The position coordinates of the sutures were extracted from the images and converted into physical coordinates. Empirical Eigenfunctions were computed from the time-varying physical coordinates, and mechanisms of sustained oscillation were explored. Results: Using the method of Empirical Eigenfunctions, physical mechanisms of sustained vocal fold oscillation were substantiated. In particular, the essential dynamics of vocal fold vibration were captured by two dominant Empirical Eigenfunctions. The largest Eigenfunction primarily captured the alternating convergent/ divergent shape of the medial surface of the vocal fold, while the second largest Eigenfunction primarily captured the lateral vibrations of the vocal fold. Conclusions: The hemi-larynx setup yielded a view of the medial surface of the vocal folds, revealing the tissue vibrations which produced sound. Through the use of Empirical Eigenfunctions, the underlying modes of vibration were computed, disclosing physical mechanisms of sustained vocal fold oscillation. The investigation substantiated previous theoretical analyses and yielded significant data to help evaluate and refine computational models of vocal fold vibration.

A Study of Vocal Fold Vibration Using a Slightly Compressible Fluid Domain

2009 ◽  
Author(s):  
D. J. Daily ◽  
S. L. Thomson
Keyword(s):  
Boundary Conditions ◽  
Incompressible Fluid ◽  
Compressible Fluid ◽  
Vocal Fold ◽  
Computational Models ◽  
Fluid Model ◽  
Vocal Folds ◽  
Moving Wall ◽  
Slightly Compressible ◽  
Vocal Fold Vibration

During human voice production, air forced from the lungs through the larynx induces vibration of the vocal folds. Computational models of this coupled fluid-solid system have traditionally utilized an incompressible fluid domain. However, studies have shown that coupling of tracheal acoustics with vocal fold dynamics is significant. Further, in the absence of compressibility, some models fail to achieve self-sustained vibration. This presentation discusses a slightly compressible airflow model, fully coupled with a vocal fold tissue model, as a possible substitute for the traditional incompressible approach. The derivation and justification of the slightly compressible fluid model are discussed. Results are reported of a study of the nature of the coupling between the fluid and vocal fold regions for both slightly compressible and incompressible fluid domains using a commercial fluid-solid finite element package. Three different types of inlet boundary conditions, including constant pressure, constant velocity, and moving wall, are explored. The incompressible and slightly compressible models with the three boundary conditions are compared with each other and with experimental data obtained using synthetic self-oscillating vocal fold models. The results are used to validate the slightly compressible flow model as well as to explore candidate boundary conditions for vocal fold vibration simulations.

Human Vocalis Contains Distinct Superior and Inferior Subcompartments: Possible Candidates for the Two Masses of Vocal Fold Vibration

1998 ◽  
Vol 107 (10) ◽  
pp. 826-833 ◽  
Author(s):  
Ira Sanders ◽  
Yingshi Han ◽  
Surinder Rai ◽  
Hugh F. Biller
Keyword(s):  
Vocal Fold ◽  
Muscle Fibers ◽  
Vocal Folds ◽  
Medial Surface ◽  
Vocal Fold Vibration ◽  
Muscle Fascicle ◽  
Superior Surface ◽  
Hematoxylin And Eosin ◽  
Thyroarytenoid Muscle ◽  
Large Muscle

It is not understood how different parts of the thyroarytenoid muscle contribute to vocal fold vibration. This study investigated the medial part of the thyroarytenoid muscle, the vocalis compartment, for anatomic differences that might suggest functionally distinct areas. Twenty human vocal folds were frontally sectioned and stained with hematoxylin and eosin. A single section from the middle of each vocal fold was magnified, and the muscle fascicles of the most superficial 25% of the vocalis compartment were then examined. In all 20 specimens the vocalis compartment could be separated into 2 plainly distinct subcompartments: the inferior vocalis compartment was composed of a single large muscle fascicle that contained densely packed muscle fibers of similar size; the superior vocalis compartment was composed of multiple small fascicles in which the muscle fibers were loosely arranged and varied greatly in size. On average, the inferior vocalis subcompartment composed 60% of the medial surface of the thyroarytenoid muscle. The superior subcompartment composed the remaining 40% of the medial surface, but also continued past the vocal ligament to make up the superior surface of the thyroarytenoid muscle. It is concluded that 2 distinct entities make up the vocalis compartment of the thyroarytenoid muscle. Their anatomy is so markedly different it suggests that they may function independently. One possibility is that they reflect the 2 masses observed in the superior and inferior aspects of the vocal fold during vibration.

scholarly journals Subject-Specific Computational Modeling of Evoked Rabbit Phonation

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Siyuan Chang ◽  
Carolyn K. Novaleski ◽  
Tsuyoshi Kojima ◽  
Masanobu Mizuta ◽  
Haoxiang Luo ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Computational Models ◽  
Three Dimensional ◽  
Model Parameters ◽  
Individual Subject ◽  
Vocal Fold Vibration ◽  
Subject Specific ◽  
Vocal Fold Dynamics ◽  
1D Model

When developing high-fidelity computational model of vocal fold vibration for voice production of individuals, one would run into typical issues of unknown model parameters and model validation of individual-specific characteristics of phonation. In the current study, the evoked rabbit phonation is adopted to explore some of these issues. In particular, the mechanical properties of the rabbit's vocal fold tissue are unknown for individual subjects. In the model, we couple a 3D vocal fold model that is based on the magnetic resonance (MR) scan of the rabbit larynx and a simple one-dimensional (1D) model for the glottal airflow to perform fast simulations of the vocal fold dynamics. This hybrid three-dimensional (3D)/1D model is then used along with the experimental measurement of each individual subject for determination of the vocal fold properties. The vibration frequency and deformation amplitude from the final model are matched reasonably well for individual subjects. The modeling and validation approaches adopted here could be useful for future development of subject-specific computational models of vocal fold vibration.

scholarly journals Numerical and Experimental Investigations on Vocal Fold Approximation in Healthy and Simulated Unilateral Vocal Fold Paralysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1817
Author(s):  
Zheng Li ◽  
Azure Wilson ◽  
Lea Sayce ◽  
Amit Avhad ◽  
Bernard Rousseau ◽  
...  
Keyword(s):  
Computational Model ◽  
Vocal Fold ◽  
High Speed ◽  
Computational Models ◽  
Ex Vivo ◽  
Vocal Fold Paralysis ◽  
Future Application ◽  
Experimental Investigations ◽  
Type I ◽  
Mri Scans

We have developed a novel surgical/computational model for the investigation of unilat-eral vocal fold paralysis (UVFP) which will be used to inform future in silico approaches to improve surgical outcomes in type I thyroplasty. Healthy phonation (HP) was achieved using cricothyroid suture approximation on both sides of the larynx to generate symmetrical vocal fold closure. Following high-speed videoendoscopy (HSV) capture, sutures on the right side of the larynx were removed, partially releasing tension unilaterally and generating asymmetric vocal fold closure characteristic of UVFP (sUVFP condition). HSV revealed symmetric vibration in HP, while in sUVFP the sutured side demonstrated a higher frequency (10–11%). For the computational model, ex vivo magnetic resonance imaging (MRI) scans were captured at three configurations: non-approximated (NA), HP, and sUVFP. A finite-element method (FEM) model was built, in which cartilage displacements from the MRI images were used to prescribe the adduction, and the vocal fold deformation was simulated before the eigenmode calculation. The results showed that the frequency comparison between the two sides was consistent with observations from HSV. This alignment between the surgical and computational models supports the future application of these methods for the investigation of treatment for UVFP.

scholarly journals 934 Remote one-to-one virtual surgical skills training: Evolving the delivery of operative skills training in the UK

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
Christian Asher ◽  
Ibrahim Ibrahim ◽  
Eyfrossini Katsarma
Keyword(s):  
Surgical Training ◽  
Wound Closure ◽  
Cost Effective ◽  
Skills Training ◽  
Training Programme ◽  
Surgical Skills ◽  
Wound Closure Techniques ◽  
Surgical Skills Training ◽  
Speciality Training ◽  
One To One

Abstract Introduction COVID-19 has had an unprecedented effect on surgical training, including prerequisite entry-level courses to speciality training. We describe the implementation of a virtual, one-to-one training programme aimed at the acquisition and retention of operative skills. Methods Enrolment commenced 8th May 2020 for wound closure techniques or an extended programme including tendon repairs, delivered by Specialist Registrars in Plastic Surgery using Zoom® (v. 5.0.5) via mobile device. Participant feedback was collected retrospectively using a 5-point scale following course completion. Results 5 participants completed the wound closure programme, and 3 the extended programme, over an average of 5 weeks, with 2 sessions per week. 5 participants were male, 3 female and were of the following grades: 2 CT2, 4 FY2, 1 FY1 and 1 medical student. A total of 103.5 hours of training was recorded to 7 September 2020. Participants reported that all virtual skills taught were readily transferable to the theatre environment. Following the course, all participants felt confident to complete the skills learnt independently, rating the course as excellent. Conclusions The COVID-19 crisis has placed insurmountable obstacles in the face of surgical training. With further validation, we aim to develop surgical skills training with virtual, easily reproducible, cost-effective, trainee centred programmes.

scholarly journals Effect of Subglottic Stenosis on Vocal Fold Vibration and Voice Production Using Fluid–Structure–Acoustics Interaction Simulation

2021 ◽  
Vol 11 (3) ◽  
pp. 1221
Author(s):  
Dariush Bodaghi ◽  
Qian Xue ◽  
Xudong Zheng ◽  
Scott Thomson
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Flow Resistance ◽  
Signal To Noise Ratio ◽  
Area Ratio ◽  
Subglottic Stenosis ◽  
Fluid Structure ◽  
Voice Production ◽  
Vocal Fold Vibration ◽  
Glottal Flow

An in-house 3D fluid–structure–acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynamics.

scholarly journals Skin stretch suturing with Nice knots in the treatment of small- or medium-sized wounds

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Jianmin Xu ◽  
Rui Chang ◽  
Wei Zhang ◽  
Chengcheng Zhang ◽  
Dezhi Zhu ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Hair Growth ◽  
Wound Closure ◽  
Skin Wound ◽  
Soft Tissue Defects ◽  
Cutaneous Sensation ◽  
The Mean ◽  
Skin Stretch ◽  
Mean Time ◽  
Tissue Defects

Abstract Background To investigate the clinical efficacy and outcomes of skin stretch suturing with self-locking sliding Nice knots in the treatment of small- or medium-sized wounds. Methods From June 2015 to May 2018, 26 patients with small- or medium-sized wounds were included in the present study. Skin stretch suturing with self-locking slide Nice knots was performed to gradually close the soft-tissue defects in these patients. The time of wound closure and healing was recorded. The color and blood supply of the skin, cutaneous sensation, the stretch of skin, and the hair growth situation of the skin wound were observed and recorded. Results There were 17 males and 9 females with an average age of 30.65 years (range, 15–48 years). The areas of the soft-tissue defects were between 3.2 × 7.1 cm and 8.0 × 15.2 cm. All patients underwent stretch suturing with self-locking slide Nice knots to close the soft-tissue defects. All wounds were successfully closed and healed. The mean time of wound closure was 10.69 days (range, 5–20 days), and the mean time of wound healing was 16.85 days (range, 10–24 days). The cutaneous sensation of skin wound recovered normally, and the color of the skin wounds was the same as that of normal skin at the last follow-up. The hair growth situation of the skin wounds also returned to normal. Conclusions This study revealed that Nice knots yielded an accepted clinical result as a new method to close small- or medium-sized wounds that was simple and less minimally invasive, resulted in progressive tension, did not return to previous results, and partially replace flaps or free skin grafts.

Comparison of lower extremity fasciotomy wound closure techniques in children: vacuum-assisted closure device versus temporary synthetic skin replacement

2018 ◽  
Vol 45 (5) ◽  
pp. 809-814 ◽  
Author(s):  
Hannah Rachel Bussell ◽  
Christoph Alexander Aufdenblatten ◽  
Corina Gruenenfelder ◽  
Stefan Altermatt ◽  
Sasha Job Tharakan
Keyword(s):  
Lower Extremity ◽  
Wound Closure ◽  
Closure Device ◽  
Vacuum Assisted Closure ◽  
Wound Closure Techniques ◽  
Skin Replacement
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