Vocal Fold Augmentation Research Articles

Systemic Effects and Absorption of Subepithelial Dexamethasone Vocal Fold Injections.

To compare the systemic changes following two office-based procedures-subepithelial vocal fold steroid injections (VFSI) and vocal fold augmentation (VFA), and to characterize the magnitude and chronicity of the effects observed. Prospective, controlled before-after comparative study. Patients prospectively underwent VFSI with 0.8-2 mg of dexamethasone or VFA. Serum cortisol, white cell count (WCC), and C-reactive protein (CRP) were measured at day 0 (pre-procedure), 1 and 7. Salivary cortisol was measured at baseline and daily for 7 days post-procedure. Fourteen patients underwent VFSI and 36 VFA. At baseline serum cortisol measured 304.6 ± 116.6 nmol/L and fell significantly to 48.1 ± 41.8 nmol/L 1 day following dexamethasone injection (p = 0.001) and recovered by day 7 to 303.7 ± 78.7 nmol/L. Salivary cortisol demonstrated a similar pattern with significant recovery demonstrated by day 3 (p = 0.001). White cell counts were affected by the systemic absorption of exogenous steroid and normalized by day 7. Patients who underwent VFA demonstrated no significant change in their serum or salivary cortisol and no significant change in their WCC. No significant changes in CRP or patient's physiological parameters were observed in either procedure. Our findings demonstrate systemic absorption of dexamethasone following VFSI, with acute hypothalamic-pituitary-adrenal (HPA) axis suppression which normalizes day 3 post-procedurally. 3 Laryngoscope, 2024.

Augmentation laryngoplasty: Results and decision plan

AbstractObjectivesAugmentation laryngoplasty represents a therapeutic choice for patients who suffer from glottic insufficiency of different etiologies. There have been multiple injectables that have been proven effective. The present study examines the short‐term effects of vocal fold augmentation on phonation, swallowing, and breathing in individuals with glottic insufficiency. In addition, a decision plan is also proposed.MethodsData from medical records and operative notes were used to conduct a retrospective cohort study on patients with glottic insufficiency who underwent vocal fold augmentation from 2016 to 2023. Hyaluronic acid, calcium hydroxyapatite, and polydimethylsiloxane were the injectable materials that were used. An analysis was conducted on phonation, breathing, swallowing, and laryngoscopy findings both before and after vocal folds' augmentation.ResultsSeventy‐nine patients were included, which represents 97 injections. The median (IQR) preoperative Voice Handicap Index‐10 (VHI‐10) score improved from 21 (15–28) to 16 (9–25) postoperatively (p < 0.001). The GRBAS scale also significantly decreased (p < 0.001). The median (IQR) preoperative Dyspnea Index score improved from 6 (0–17) to 2 (0–10) postoperatively (p < 0.05). Laryngoscopic findings showed significant improvement in the bulk of the vocal folds. There was no significant change in swallowing.ConclusionsIn case of dysphonia secondary to glottic insufficiency, augmentation laryngoplasty using various injectable materials has proven to be an effective option across a range of different etiologies, as it results in significant improvements in voice quality. The choice of the injectable material depends upon the severity and the etiology of glottic insufficiency.

Temporary Vocal Fold Augmentation Outcomes for Refractory Chronic Cough with Concurrent Nonparalytic Glottic Insufficiency due to Vocal Fold Atrophy

ObjectiveDetermine the effect of temporary vocal fold augmentation on refractory chronic cough in patients with glottic insufficiency due to vocal fold atrophy. MethodsRetrospective electronic chart review was conducted for patients with a diagnosis of bilateral vocal fold atrophy and refractory chronic cough undergoing vocal fold augmentation with carboxymethylcellulose. Patients with vocal fold immobility were excluded, and cough must have been present for at minimum 8 weeks. VHI-10, CSI, and RSI scores along with subjective overall patient report of chronic cough improvement were collected. ResultsA total of 28 patients underwent 30 vocal fold augmentation procedures with carboxymethylcellulose. All had undergone extensive cough work-up and treatment trials prior to their augmentation procedure. From chart review, 13 overall subjectively reported satisfactory improvement in their cough, 5 reported partial improvement, and 7 reported no improvement in their cough. An uncertain effect on cough was documented in 5 (either patient was uncertain or no mention of cough symptom in the interval chart history note). For those subjects with both pre- and post-augmentation data, mean pre-augmentation CSI: 22.08 + 6.8 (n=13); VHI-10: 13.6 + 8.9 (n=18); RSI: 22.4 + 7.5 (n=17). Mean post-augmentation CSI was 20.7 + 9.2 (n=13); VHI-10: 15.2 + 8.2 (n=18); RSI: 21.1 + 5.8 (n=17). Mean pre-post change in CSI was -1.4 + 5.1 (p=0.175, n=13, range -10 – +6). ConclusionsVocal fold augmentation seems to provide subjective cough improvement in some patients with concurrent glottic insufficiency due to vocal fold atrophy and refractory chronic cough. It can be offered as a diagnostic trial, on which further augmentation may be offered, for patients with persistent cough despite prior work-up and treatment trials. Further controlled prospective studies are needed to identify factors that are predictive of successful cough improvement following vocal fold augmentation, as well as the effect of durable augmentation in those patients who had improvement with a diagnostic trial.

3D-exoscopic microlaryngoscopy in phonosurgery for glottic insufficiency

PurposeWe hypothesized that using a 3D-exoscope (3Dex) in microlaryngoscopic phonosurgery is non-inferior to using a standard operating microscope (OM). To compare the above, we utilized a 3Dex and an OM for microlaryngoscopic vocal fold augmentation with autologous fat in patients with glottic insufficiency and compared the procedure itself and the long-term impact of vocal fold augmentation on subjective and objective voice parameters in both groups.Methods36 patients with glottic insufficiency received microlaryngoscopic laryngeal augmentation with autologous fat. A 3Dex was utilized in 24 cases for visualization and compared to twelve cases in which an OM was used. Voice parameters were evaluated over a period of twelve months.ResultsComparison of operation time and voice parameters between the 3Dex and OM groups did not reveal significant differences. Significant improvement of mean voice quality in all parameters excluding roughness was observed at 3 and 6 months followed then by a slight decrease of voice quality parameters between the 6 and 12 months interval in both groups.ConclusionOur findings indicate no difference concerning operation time and outcome between the use of a 3Dex and an OM in phonosurgery. Our results highlight a significant voice improvement after vocal fold augmentation with autologous fat in glottic insufficiency mediated dysphonia. The smaller viewing system, better ergonomics for the primary surgeon and the assistant and a direct view for the entire surgical team make a 3Dex an interesting alternative for visualization in microlaryngoscopic phonosurgery.

Tragal Cartilage Versus Fascia Lata Implant for Treatment of Glottic Insufficiency: A Randomized Clinical Trial

40 patients with glottic insufficiency over the age of 18 years old who presented to the otorhinolaryngology outpatient clinic at (blinded for peer review) were the subjects of this prospective study. Two equal groups (A&B) of patients were randomly separated. For group (A), the tragal cartilage implants were used to enhance the vocal folds; for group (B), fascia lata implants were utilized. Auditory perceptual assessment of voice (APA), voice handicap index (VHI), and computerized speech lab (CSL) were used for voice assessment, penetration aspiration score (PAS), and dysphagia handicap index (DHI) for aspiration assessment during preoperative and postoperative evaluation. In both groups, there was a statistically significant difference between preoperative and postoperative subjective and objective parameters used for voice and aspiration assessment (APA, VHI, CSL, PAS, and DHI). There was a statistically non-significant difference between the two groups one and 12 months postoperatively except for only noise to the harmonic ratio (N/H ratio) in group A which showed more significant improvement than group B. Vocal fold augmentation using the tragal cartilage and fascia lata grafts in glottic insufficiency patients is effective in improving hoarseness of voice and aspiration. Both grafts result in long-term improvement (at least 12 months), however tragal cartilage graft is easier to implant and more stable postoperatively than the fascia lata graft.

Use of a Novel Hypercrosslinked Carbohydrate Scaffold for Vocal Fold Medialization in an Ovine Model.

Vocal fold medialization is commonly performed for glottic insufficiency and vocal fold immobility. Currently available materials are temporary injectables or synthetic implants. Acellular scaffolds may allow vocal fold augmentation with autologous tissue via host cell migration. The purpose of this investigation was to evaluate the use of a novel carbohydrate scaffold as a medialization implant. Animal model. Academic medical center. Unilateral type I medialization thyroplasty was performed in 3 Dorper cross ewes using a hypercrosslinked carbohydrate polymer (HCCP) scaffold. Animals were monitored for 4 weeks for general well-being, dyspnea, and weight loss. The animals were euthanized at 4 weeks and the larynges harvested. Histologic evaluation was performed to assess for adverse tissue reaction, migration, degradation, and biocompatibility. No adverse events were reported. No animals lost weight or displayed evidence of dyspnea. Histology demonstrated ingrowth of host cells and neovascularization with minimal peri-implant inflammatory reaction. Cellular ingrowth into the scaffold was predominately made up of fibroblasts and early inflammatory cells. Scaffold shape was grossly maintained as it underwent degradation and replacement with host tissue. Migration of the implant material was not observed. Vocal fold medialization in an ovine model with an HCCP scaffold resulted in the ingrowth of host cells with minimal peri-implant inflammation. Scaffold shape was maintained without evidence of migration as it underwent replacement with host tissue. Further research is required to assess long-term efficacy in comparison to currently available implants.

Decreasing polymethyl methacrylate bone cement concentration extends working and setting times in vitro.

To determine setting and temperature properties of diluted polymethyl methacrylate (PMMA) bone cement in vitro to assess utility for vocal fold augmentation in horses. 4 dilutions of PMMA equivalent to volumes of 15 mL, 20 mL, 25 mL, and 30 mL PMMA powder (PMMAp) in 10 mL solvent. For each volume PMMAp, setting times (tset), peak temperatures (Tmax), and times to peak temperature (tmax) were determined using a temperature data logger in a 4-mL volume of PMMA. Injectability was assessed in vitro by documenting the force required to inject 0.2 mL PMMA through an 18-gauge 3.5-inch spinal needle attached to a 6-mL syringe at 1-minute intervals. Working time (twork) was calculated from a linear regression of injectability. Peak temperatures increased with increasing volume of PMMAp: 56 °C, 86 °C, 99 °C, and 101 °C. Times for tset, twork, and tmax were inversely proportional to PMMA concentrations, resulting in tset of 23, 21, 17, and 14 minutes; twork of 22.75, 12.25, 7, and 4 minutes; and tmax of 28, 24, 19, and 16 minutes, respectively, for 15, 20, 25, and 30 mL PMMAp. Pairwise comparisons for all analyses were significant apart from Tmax for 25 and 30 mL PMMAp (P = .96) and twork for 20 and 25 mL PMMAp (P = .06). Decreasing the concentration of PMMA bone cement resulted in longer working times and setting times; however, peak temperatures did not differ between the 2 strongest concentrations. Further research is warranted to quantify diluted PMMA properties for in vivo use for vocal fold augmentation in horses.

Training for Awake, Office-Based Laryngeal Procedures-The Laryngology Fellow's Perspective.

The aim was to explore recent laryngology graduates' perspectives on their experience, competency, and challenges learning office-based procedures during fellowship training in the United States and Canada. Anonymous 22-item questionnaire survey was distributed electronically to fellowship-trained laryngologists having completed fellowship within past 5 years. Ninety fellowship-trained laryngologists between 2018 and 2022 were surveyed. Response rate was 48.9% (n = 44), 1 declined participation, with 20 different fellowship programs represented. Fellows were frequently provided the opportunity to act as primary surgeon for most procedures, except for laryngeal botulinum toxin injection, diagnostic laryngeal electromyography, trans-nasal esophagoscopy, secondary tracheoesophageal puncture, and high-resolution pharyngeal manometry. A majority reported high (n = 27, 62.8%) or moderate (n = 12, 27.9%) confidence with vocal fold injection augmentation. Various techniques were taught: transoral (74.4%), cricothyroid (74.4%), thyrohyoid (69.8%), transcartilagenous (14.0%), and catheter-needle (25.6%). Numerous statistically significant associations with independent procedure involvement and competence were identified. Laryngeal botulinum toxin injection was a procedure performed with high frequency but low volume of independent fellow involvement, and the procedure with which fellows reported wanting more practice learning. Most common training barriers included patient being awake, patient consenting to trainee performing the procedure, and the technical challenge/complexity of the procedure. Teaching methods/tools largely focused on informal debriefing (97.3%) and case by case troubleshooting (81.1%). Laryngology fellows are well trained with favorable perceived levels of competence for numerous office-based procedures, particularly vocal fold injection augmentation. Procedures for which fellows reported a low level of independent participation trended towards lower perceived competency. 5 Laryngoscope, 134:873-881, 2024.

Evaluation and Management of Inflammatory Reactions to Vocal Fold Injection Laryngoplasty with Hyaluronic Acid

Inflammatory reaction to vocal fold injection laryngoplasty with hyaluronic acid (HA) is a rare condition whose optimal management is not established. In this study, we aim to review the presentation of these reactions and outline an approach for evaluation and management. We performed a retrospective review of all patients at our institution who underwent vocal fold injection augmentation with HA during the period extending from August 2018 until October 2022. We then identified patients with postinjection inflammatory reaction and reviewed demographic data, indication for injection, amount of HA injected, setting of procedure, and symptoms. The types of complication, management plan, onset, and time to complete resolution were also recorded. A comprehensive literature search for similar complications was conducted for comparative analysis. Once the available data were aggregated with our institutional experience, we developed an algorithmic approach to manage this condition. We identified 83 patients (124 vocal folds) who underwent vocal fold injection laryngoplasty with HA over a 4-year period. Four patients (4.8%) had a postprocedure inflammatory reaction (5.6% of all vocal folds). Of the four patients, three presented with dyspnea and stridor, while one presented with dysphonia, with onset of symptoms ranging from 24 to 48hour postinjection. All patients were treated with corticosteroids. For comparative analysis, we identified 24 patients from the literature with reported inflammatory reactions to HA. We suggest an algorithmic approach to managing laryngeal inflammation following HA injection. Familiarity with treatment for this rare complication is essential to avoid significant morbidity and achieve optimal outcomes.

446. VOCAL FOLD AUGMENTATION REDUCES PNEUMONIA INCIDENCE IN PATIENTS WITH IATROGENIC RECURRENT LARYNGEAL NERVE PALSY AFTER ESOPHAGECTOMY

Abstract Background Recurrent laryngeal nerve (RLN) palsy is a significant complication associated with esophagectomy, resulting in a high incidence of pneumonia and a poor quality of life. Vocal fold augmentation (VFA) can help alleviate the associated symptoms of dysphonia. We aimed to investigate the impact of VFA on pneumonia incidence in patients suffering from RLN palsy after esophagectomy. Methods This is a retrospective cohort study. Patients who underwent esophagectomy at our center from 2003 to 2022, and experienced right, left or bilateral RLN palsy postoperatively were selected from a prospectively managed database. VFA consisted of medialisation thyroplasty, injection laryngoplasty, arytenoid adduction or a combination of these procedures. Pneumonia was defined as lung changes on chest x-ray, along with clinical evidence of infection within six months after esophagectomy. Pearson’s chi-squared test was used to assess the difference in pneumonia rates. Univariate and multivariate logistic regression analyses were used to identify associations between variables and the outcome of pneumonia. Results A total of 107 esophagectomy patients with RLN palsy were included. The overall palsy rate was 14.5%. 41 patients (38.3%) underwent VFA. Of the patients who underwent VFA, 13 (31.7%) underwent medialization thyroplasty, 26 (63.4%) underwent injection laryngoplasty, 1 (2.4%) underwent injection laryngoplasty and medialization thyroplasty, and 1 (2.4%) underwent injection laryngoplasty and arytenoid adduction. Pneumonia rate (14.6%) for patients who underwent VFA was significantly lower than that of patients without VFA (47.0%, P < 0.001). On univariate and multivariate analyses, patients who underwent VFA were less likely to suffer from pneumonia compared to those without VFA (OR = 0.194, P = 0.001). Conclusion Vocal fold augmentation reduces pneumonia incidence in patients with recurrent laryngeal nerve palsy after esophagectomy.

448. PREDICTORS OF RECURRENT LARYNGEAL NERVE PALSY RECOVERY FOLLOWING ESOPHAGECTOMY

Abstract Background Recurrent laryngeal nerve (RLN) palsy is a serious complication of esophagectomy that significantly impacts patients’ quality of life. This condition can be permanent or temporary, and identifying the factors associated with recovery can guide treatment options and manage patient expectations. We aimed to investigate the predictors associated with recovery from RLN palsy after esophagectomy. Methods We selected patients who underwent esophagectomy between 2003 and 2022, had a minimum survival and follow-up of 6 months, and experienced right, left, or bilateral RLN palsy from a prospectively managed database. Recovery was defined as restoration of vocal fold mobility within 6 months, irrespective of dysphonia symptoms while permanent injury was defined as persistent vocal cord palsy after six months. Univariate and multivariable logistic regression analyses were used to identify associations between variables and the likelihood of recovery. Results The overall RLN palsy rate was 14.5%. Ninety-five esophagectomy patients with RLN palsy were included. The mean age at operation was 64.4 years. Fifty-two patients (54.7%) recovered from vocal cord palsy. Sixty-four patients (67.4%) underwent minimally-invasive or video-assisted thoracoscopic esophagectomy. On multivariable analysis, patients who underwent neoadjuvant therapy (OR = 0.250, P = 0.012), vocal fold augmentation (OR = 0.283, P = 0.009), or reconstruction via the retrosternal route (OR = 0.326, P = 0.036) or right chest (OR = 0.088, P = 0.046) with reference to the orthotopic route, were less likely to recover from RLN palsy. Conclusion Neoadjuvant therapy, vocal fold augmentation and the route of esophageal reconstruction were significant predictors of recovery from RLN palsy after esophagectomy.

Changes in vocal fold gene expression and histology after injection augmentation in a recurrent laryngeal nerve injury model.

To investigate changes in neuroregenerative pathways with vocal fold denervation in response to vocal fold augmentation. Eighteen Yorkshire crossbreed swine underwent left recurrent laryngeal nerve transection, followed by observation or augmentation with carboxymethylcellulose or calcium hydroxyapatite at two weeks. Polymerase chain reaction expression of genes regulating muscle growth (MyoD1, MyoG and FoxO1) and atrophy (FBXO32) were analysed at 4 and 12 weeks post-injection. Thyroarytenoid neuromuscular junction density was quantified using immunohistochemistry. Denervated vocal folds demonstrated reduced expression of MyoD1, MyoG, FoxO1 and FBXO32, but overexpression after augmentation. Healthy vocal folds showed increased early and late MyoD1, MyoG, FoxO1 and FBXO32 expression in all animals. Neuromuscular junction density had a slower decline in augmented compared to untreated denervated vocal folds, and was significantly reduced in healthy vocal folds contralateral to augmentation. Injection augmentation may slow neuromuscular degeneration pathways in denervated vocal folds and reduce compensatory remodelling in contralateral healthy vocal folds.

De novo tissue formation using custom microporous annealed particle hydrogel provides long-term vocal fold augmentation

Biomaterial-enabled de novo formation of non-fibrotic tissue in situ would provide an important tool to physicians. One example application, glottic insufficiency, is a debilitating laryngeal disorder wherein vocal folds do not fully close, resulting in difficulty speaking and swallowing. Preferred management of glottic insufficiency includes bulking of vocal folds via injectable fillers, however, the current options have associated drawbacks including inflammation, accelerated resorption, and foreign body response. We developed a novel iteration of microporous annealed particle (MAP) scaffold designed to provide persistent augmentation. Following a 14-month study of vocal fold augmentation using a rabbit vocal paralysis model, most MAP scaffolds were replaced with tissue de novo that matched the mixture of fibrotic and non-fibrotic collagens of the contralateral vocal tissue. Further, persistent tissue augmentation in MAP-treated rabbits was observed via MRI and via superior vocal function at 14 months relative to the clinical standard.

Preliminary Results on the Safety and Efficacy of Silk-Hyaluronic Acid for Treatment of Glottic Insufficiency

Silk-Hyaluronic Acid (Silk-HA) is a novel vocal fold augmentation material that has been used in humans since July 2020. There is a paucity of published data on Silk-HA and its longevity remains a question. This study aimed to evaluate a single surgeon's initial experience performing Silk-HA injection laryngoplasty for the treatment of glottic insufficiency. Retrospective chart review of Silk-HA injections between July 2020 and December 2021. Subject demographics, diagnoses, volume of material injected, VHI-10 data, and complications were collected. A blinded perceptual voice analysis of voice samples was performed by two voice-specialized speech-language pathologists (SLP) for a subset of unilateral vocal fold paralysis patients before and 3-months following silk-HA injection. Univariate assessment of the change in VHI-10 and perceptual voice analyses at 3-month follow up was determined. 58 patients (43.1% female) underwent Silk-HA injection with a mean age of 64 (range 21-88). 38 subjects had unilateral paralysis (65.6%), and the remaining had scar, atrophy, paresis or a combination thereof. 49 injections were unilateral (84.5%). Mean volume of silk injected was 0.26 mL. Complications were rare, most notable though for 2 admissions for dyspnea and laryngoscopic evidence of hemi-laryngeal edema (3.4%). Mean change in CAPE-V overall severity rating was -32.9 (P<0.0001), and VHI-10 was -14.6 ± 10 (P=0.0013). 14 patients underwent a repeat silk-HA injection for ongoing glottic insufficiency (loss of augmentation vs under-augmentation). Preliminary results for Silk-HA show potential for ongoing improvement of glottic insufficiency at 3 months from date of augmentation. Clinician and patient perception of voice outcomes showed overall improvement at three months, though longevity remains to be determined. While overall well tolerated and without serious complications in 96% of the cohort, patients should be counseled on the potential for airway edema and symptomatic dyspnea requiring steroid management and observation.

Acoustic and videoendoscopic effects of temporary vocal fold augmentation in an office-based setting: a quasi-experimental study

BackgroundVocal-fold augmentation is a continuously developing treatment modality for glottic insufficiency. Patients with glottic insufficiency attend the phoniatrics clinics with increasing frequency. Glottic insufficiency may be due to vocal-fold paralysis, paresis, atrophy, sulcus vocalis, scarring, and vocal-fold deficiency after laryngeal surgery. A variety of materials exist for injection augmentation. This follow-up study aimed to assess the short-term as well as long-term outcomes of vocal-fold injection with calcium hydroxyapatite (CaHA) in patients with glottic gap 1–3 mm.MethodThis study included 25 patients with glottic insufficiency who underwent injection augmentation with CaHA. All patients were scheduled for voice evaluation using a comprehensive subjective and objective battery of assessments. Assessments were performed before the procedure and after the procedure at 2 months and at 1 year.ResultsPerceptual voice quality assessed with the GRBAS scale improved and the results were stable after 1 year. Shimmer and HNR improved continuously through the follow-up sessions, while jitter and f0 showed slight improvement after CaHA injection.ConclusionVoice improvement after injection of CaHA requires a minimum of 2 months to develop and may last for a long period.

Vocal Fold Augmentation: Current Review

Glottic closure is essential for vocalization and airway protection. Several pathological conditions cause glottic insufficiency, such as vocal fold paralysis and presbylarynx, which is the age-related atrophy of laryngeal muscle. Injection laryngoplasty is common technique to treat glottic insufficiency, because it can be easily and inexpensively performed in an outpatient setting. Different injection material should be selected according to the purpose and patient condition before the procedure. Ideal material for injection laryngoplasty must be biocompatible, and the injected volume should be maintained for the desired duration without migration. Further, it will be better if it could be easily injected and removed. In this article, we reviewed the published research related to material for the injection laryngoplasty and tried to think about the limitations of current studies and the future direction of treatment.

Variations in Practices and Preferences of Vocal Fold Injection Materials: A National Survey.

Vocal fold injection augmentation (VFI) is a common procedure for the treatment of glottic insufficiency. Material options for VFI and decisions regarding material selection are not standardized and often based on clinician preference. This study aims to understand the variations in provider preference and utilization of injectable materials for VFI. A 40-question survey was sent to 158 academic laryngologists. Questions pertained to the type of injectable materials used including brand preferences and rationale for preferences. Ninety-seven of the 158 laryngologists contacted participated in the survey (61.4%). The most frequently used injectable materials were Hyaluronic Acid (HA)-based products. Carboxymethylcellulose (CMC)-based products were preferred for trial augmentation (57.2%), HA-based products were preferred for acute/subacute vocal fold paralysis, presbyphonia, and sulcus/scar (54.2%, 61.5%, 44.7%, 41.7% respectively), and Calcium Hydroxyapatite (CaHA)-based products were preferred for long-term paralysis (28.1%). CMC-based products were discontinued by 21.8% of participants, largely due to quick material resorption. 17.8% of participants discontinued HA-based products largely due to adverse events and 26.0% abandoned CaHA-based products mostly due to inflammatory properties causing vocal fold stiffness and material unpredictability. Over 30% of respondents reported wanting to reinitiate micronized alloderm Cymetra® as an available injectable. Our survey demonstrated that there are significant variations in practice and preferences in regard to injectable material selection for VFI. As there is limited data on the direct material comparison, understanding the rationale behind these variations is crucial to guide new providers in material selection and provide information to patients undergoing these procedures. 5 Laryngoscope, 133:1176-1183, 2023.

Injection laryngoplasty with hyaluronic acid for glottal insufficiency in unilateral vocal fold paralysis: a systematic review of the literature.

Glottal insufficiency, mostly caused by unilateral vocal fold paralysis (UVFP) or vocal fold atrophy can be treated by injection laryngoplasty (IL). Materials such as hyaluronic acid (HA) gels are now widely available and used to improve voice quality. Various durability and effects of HA injection laryngoplasties have been reported. The aim of this study is to provide a systematic review of the literature for the use of HA in injection laryngoplasties. A systematic literature search was conducted in PubMed and Cochrane Libraries. Three reviewers assessed original research studies concerning vocal fold augmentation with HA for eligibility. English written full-text human studies from 2000 to 2020 with EBM level 1b-2 were included. In vitro studies, animal studies, case reports, case-control studies, correspondence and review articles, and articles with other injection materials were excluded. Demographical data, indication, type of HA, evaluation methods, follow-up, durability of implanted material and complications were assessed. A total number of 311 articles were found in PubMed and Cochrane Library, 13 studies were eligible for final analysis with 1063 patients, mean age of patients was 58.7years. Main indication for HA IL was unilateral vocal fold paralysis, evaluation methods were subjective-VHI (Voice Handicap Index) questionnaire and objective-acoustic and aerodynamic measurements, mean time of follow-up was 5.9months. Large-particle HA gels were more favorable for longer durability than small-particle HA, reported time of resorption of HA gels ranges between 6 and 12months, and complication rate was low. Hyaluronic acid injection laryngoplasty increases voice quality, improves results of voice therapy, and can be recommended as overlap treatment before permanent medialization surgery. Compared to other injected materials, HA seems to have more favorable effect on vibratory functions of the vocal folds and thus on the voice quality parameters.

Microfluidic Synthesis of Microgel Building Blocks for Microporous Annealed Particle Scaffold

The microporous annealed particle (MAP) scaffold platform is a subclass of granular hydrogels. It is composed of an injectable slurry of microgels that can form a structurally stable scaffold with cell-scale porosity in situ following a secondary light-based chemical crosslinking step (i.e., annealing). MAP scaffold has shown success in a variety of regenerative medicine applications, including dermal wound healing, vocal fold augmentation, and stem cell delivery. This paper describes the methods for synthesis and characterization of poly(ethylene glycol) (PEG) microgels as the building blocks to form a MAP scaffold. These methods include the synthesis of a custom annealing macromer (MethMAL), determination of microgel precursor gelation kinetics, microfluidic device fabrication, microfluidic generation of microgels, microgel purification, and basic scaffold characterization, including microgel sizing and scaffold annealing. Specifically, the high-throughput microfluidic methods described herein can produce large volumes of microgels that can be used to generate MAP scaffolds for any desired application, especially in the field of regenerative medicine.

Microfluidic Synthesis of Microgel Building Blocks for Microporous Annealed Particle Scaffold.

The microporous annealed particle (MAP) scaffold platform is a subclass of granular hydrogels. It is composed of an injectable slurry of microgels that can form a structurally stable scaffold with cell-scale porosity in situ following a secondary light-based chemical crosslinking step (i.e.,annealing). MAP scaffold has shown success in a variety of regenerative medicine applications, including dermal wound healing, vocal fold augmentation, and stem cell delivery. This paper describes the methods for synthesis and characterization of poly(ethylene glycol) (PEG) microgels as the building blocks to form a MAP scaffold. These methods include the synthesis of a custom annealing macromer (MethMAL), determination of microgel precursor gelation kinetics, microfluidic device fabrication, microfluidic generation of microgels, microgel purification, and basic scaffold characterization, including microgel sizing and scaffold annealing. Specifically, the high-throughput microfluidic methods described herein can produce large volumes of microgels that can be used to generate MAP scaffolds for any desired application, especially in the field of regenerative medicine.