Citations

The lamina propria within the vocal fold (VF) is a complex multi-layered tissue that increases in stiffness from the superficial to deep layer, where this characteristic is crucial for VF sound production. Tissue engineered scaffolds designed for VF repair must mimic the biophysical nature of the native vocal fold and promote cell viability, cell spreading, and vibration with air flow. In this study, we present a unique tri-layered, partially-degradable hydrogel scaffold that mimics the multi-layered structure of the VF lamina propria. Using thiol-norbornene photochemistry, tri-layered hydrogel scaffolds were fabricated via layer-by-layer stacking with increasing polymer concentration from the top to middle to deep layer. Mechanical analysis confirmed hydrogel modulus increased with increasing polymer concentration. Partially-degradable hydrogels promoted high cell viability and cell spreading in 3D as assessed via live/dead and cytoskeleton staining, respectively. Importantly, partially-degradable hydrogels maintained some degree of the 3D polymer network following protease exposure, while still enabling encapsulated cells to remodel their local environment via protease secretion. Finally, the tri-layered hydrogel scaffold successfully vibrated and produced sound in proof-of-concept air flow studies. This work represents a critical first step towards the design of a multi-layered, hydrogel scaffold for vocal fold tissue engineering.

Objectives/HypothesisDevelop a patient‐specific tissue engineered construct for laryngeal reconstruction following a partial laryngectomy.Study DesignBench and animal research.MethodsA construct made from a porous polyethylene scaffold shaped in a canine‐specific configuration and seeded with autologous canine adipose‐derived stem cells in fibrin glue was implanted in a canine following a partial laryngectomy. After 1 year, the construct was first evaluated in vivo with high‐speed imaging and acoustic–aerodynamic measures. It was then explanted and evaluated histologically.ResultsThe canine study at 1 year revealed the construct provided voicing (barking) with acoustic and aerodynamic measures within normal ranges. The canine was able to eat and breathe normally without long‐term support. The construct was integrated with epithelialization of all areas except the medial portion of the vocal fold structure. No anti‐infective agents were needed after the standard perioperative medications were completed.ConclusionThis study provided a successful first step toward developing a patient‐specific composite construct for patients undergoing partial laryngectomies.Level of EvidenceNA Laryngoscope, 132:S1–S11, 2022

ObjectiveThe study aims to demonstrate the reproducibility and feasibility of creating a hemilaryngeal model with a medialized vocal fold (VF) using 3‐dimensional (3D) modeling techniques in both healthy larynges and those affected by cancer.Study DesignThree‐dimensional modeling of human larynges.SettingTertiary academic referral center and regenerative medicine laboratory.Subjects and MethodsComputed tomography (CT) scans from 10 healthy control and 10 patients with laryngeal cancer were segmented and imported into 3D modeling software. The larynx was cut sagittally to create a hemilaryngeal model and the vocal fold medialized. Measurements were taken from the CT and 3D model data and compared.ResultsAll control modeling data closely matched the CT data and were not statistically different from each other. There was a significant correlation between subglottic anteroposterior diameter and VF length (r2 = 0.78, P =. 0008), and it may be a valuable tool to infer true VF dimension in cases where disruption has occurred. The modeling data from patients with cancer did not show statistical difference to the control data, showing that accurate modeling can also be achieved in patients with laryngeal cancer.ConclusionCT scan‐based 3D modeling of the larynx and VF is possible and reproducible. The results closely match those previously reported in the literature and can also be replicated in cases with laryngeal cancer. This study paves the way for future de novo fabricated laryngeal scaffolds that can be synthesized using 3D printers and tailored to meet surgical demands.

Stereoscopic particle image velocimetry (SPIV) is a variant of particle image velocimetry (PIV) that allows for the measurement of three components of velocity along a plane in a flow field. In PIV, particles in the flow field are tracked by reflecting laser light from tracer particles into two angled cameras, allowing for the velocity field to be determined. Particle shadow velocimetry (PSV) is an inherently less expensive velocity measurement method since the method images shadows cast by particles from an LED backlight instead of scattered light from a laser. Previous studies have shown that PSV is an adequate substitute for PIV for many two-dimensional, two-component velocimetry measurements. In this work, the viability of the two-dimensional, three-component stereoscopic particle shadow velocimetry (SPSV) is demonstrated by using SPSV to examine a simple jet flow. Results obtained using SPIV are also used to provide benchmark comparison for SPSV measurements. Results show that in-plane and out-of-plane velocities measured using SPSV are comparable to those measured using SPIV.