Vocal fold injection: review of indications, techniques, and materials for augmentation

The Additive Effectiveness of Inspiratory Muscle Training on Glottic Closure and Subjective Voice Outcomes of Patients With Benign Lesion After Hyaluronic Acid Laryngoplasty

OBJECTIVES

For patients with glottic insufficiency disease, injection laryngoplasty is a rapid and efficient management option that complements voice therapy. Some studies have indicated that respiratory muscle training may also show promise in patients with voice disorders. However, the effect of respiratory muscle training in patients with glottic insufficiency was reported to be limited, and whether it provides additional benefit after standard management requires further evaluation. We aimed to investigate the effectiveness of inspiratory muscle training on glottis closure and patient-reported voice quality in glottic insufficiency patients who had been treated with hyaluronic acid injection.

STUDY DESIGN

Retrospective observational study.

METHODS

We included 46 patients with glottic insufficiency who had undergone hyaluronic acid injection. Twenty of them had undergone inspiratory muscle training during three months. We measured patients' changes in glottic status according to the normalized glottal gap area and bowing index, as well as voice quality of life according to the voice handicap index 10 and the voice outcome survey, before and after training.

RESULTS

Patients who underwent inspiratory muscle training had higher odds of experiencing better improvement in all scores. The range of odds ratios ranged from 2.5 to 6.3 for changes in scores, and from 3.8 to 22.2 for changes in score percentages. Of note, the effect of training on percentage changes in the normalized glottal gap area score was significant (P= 0.0127) after adjustment for the duration of vocal disease, body mass index and BMI, and history of gastroesophageal reflux disease.

CONCLUSIONS

Inspiratory muscle training can improve the glottal gap after injection laryngoplasty, and may be applied in clinical practice.

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

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

National Trends in Treatment of Acute Unilateral Vocal Fold Paralysis at Tertiary Care Voice Centers

Objective

Acute unilateral vocal fold paralysis (UVFP) management differs across the United States. This study aims to characterize current trends in UVFP treatment at US tertiary care voice centers.

Data Sources

A survey was distributed to laryngologists at 51 tertiary care voice centers within the CoPE (Vocal Cord Paralysis Experience) Collaborative.

Review Methods

Participants provided information on voice center, laryngologist, and speech-language pathologist (SLP) characteristics, diagnostic practices, treatment decision-making, and therapies offered for acute UVFP (symptoms present for ≤ 6 months). National trends in diagnostic and treatment practices were evaluated.

Results

Among the 51 CoPE centers, 48 completed the questionnaire (17% Northeast, 33% South, 35% Midwest, 15% West). Most centers (77%) had 1-2 laryngologists managing acute UVFP, with SLP availability varying widely (0-8+ per site). Diagnostic practices varied significantly: only 26% of centers routinely measured mean airflow during phonation, 47% recorded maximum phonation time (MPT), and 53% assessed GRBAS. Treatment commonly included vocal fold injection augmentation, alone or combined with voice therapy, with injections typically administered 3-4 weeks after diagnosis (83%). Hyaluronic acid (95%), PROLARYN GEL (60%), and calcium hydroxyapatite (56%) were the most frequently used materials. Injection procedures were performed "often" in clinic settings (90%) and "rarely" or "never" in the operating room (42%) and hospital bedside (56%).

Conclusion

Significant variability exists in the diagnostic testing, evaluation, and treatment of acute UVFP across tertiary care centers. Future studies are warranted to explore the causes of these variations and assess the role of multidisciplinary approaches in optimizing UVFP care.

Level of Evidence

3.

In-Office Hyaluronic Acid Injection of Vocal Folds in Patients with Presbyphonia

Objective: to evaluate the advantages and disadvantages of injection laryngoplasty with hyaluronic acid in patients older than 65 years with presbyphonia. Study Design: a retrospective observational study. Setting: an academic secondary medical center. Methods: This study was performed using a group of patients diagnosed with presbyphonia who were treated using injection laryngoplasty with hyaluronic acid and underwent a minimum follow-up of 12 months. Subjective parameters such as the Voice Handicap Index-10 (VHI-10) and the GRBAS scale (grade, roughness, breathiness, asthenia, strain) were measured, as well as objective parameters such as the closure defect area. The medical records of patients undergoing this procedure during the 2020-2023 period were reviewed. An analysis of the demographic and clinical variables of the group was performed, as well as the values of the VHI-10, GRBAS, difference, and improvement of the area of closure defect before and after the procedure, along with the treatment duration and sensation of improvement. Results: The mean pre- and postoperative VHI-10 decreased from 26.8 to 19.6, showing significant differences (p = 0.007). The postoperative GRBAS mean score was 5.6 and normality can be assumed when it is below 9. Out of the 16 patients, 11 of them reported subjective improvement in their symptoms. More than half of them showed an improvement in the closure defect greater than 80%, with a significant reduction in the area (p < 0.001). Conclusions: hyaluronic acid injection in patients with presbyphonia produced a clear subjective improvement in voice quality and a decrease in the closure defect area.

Comparison of Complications of Injection Laryngoplasty via Direct Versus Flexible Laryngoscopy

OBJECTIVES

Injection laryngoplasty (IL) is commonly performed for glottic insufficiency and has historically been performed under general anesthesia via direct laryngoscopy (DL), with an increasing number of procedures being performed in the office setting via flexible laryngoscopy (FL). Existing literature regarding complications of IL primarily addresses immediate peri-procedural complications and adverse reactions to the injection material. This is the first study utilizing a large multi-institutional database comparing complications of IL performed via DL versus FL.

STUDY DESIGN

Retrospective database study.

METHODS

Patients who underwent IL were queried on the TriNetX Research platform from 2017 to 2024. Patients were stratified by injection approach (DL or FL). The two cohorts were balanced via propensity score matching for age at time of procedure, sex, race, and ethnicity. Diagnoses of dyspnea, stridor, dysphagia, odynophagia, persistent dysphonia, and laryngeal edema were compared between the two groups from the day of the procedure to three months postprocedure.

RESULTS

A total of 6921 and 6832 patients underwent IL via DL and FL, respectively. Patients undergoing IL via DL had higher odds of experiencing dyspnea (OR = 1.375, P = 0.0014), stridor (OR = 4.443, P < 0.0001), and laryngeal edema (OR = 1.782, P < 0.0001), but had improved voice outcomes with lower odds of persistent dysphonia (OR = 0.568, P < 0.0001). Odds of developing dysphagia or odynophagia were comparable between the two cohorts.

CONCLUSION

IL procedures performed via DL were more likely to be associated with airway-related complications but had better voice outcomes up to three months after the procedure. Future study is needed to better determine the etiology of these complications to improve safety and efficacy.

Prolonged persistence of hyaluronic acid after suboptimal vocal fold injection

Hyaluronic acid (HA) is a commonly used injectable material in temporary vocal fold injections (VFI) in patients with unilateral vocal fold paralysis (UVFP). Hyaluronic acid has generally been known for its three-six months of longevity following VFI. Owing to recent advances in cross-linking technologies, the longevity of HA-based materials, including deep-volumizing cross-linked HA used in VFI, has been improved. However, persisting injectable material in the subepithelial space poses undesirable complications following VFI. Herein, we report 2 cases of unexpected persistence of superficially injected cross-linked HA. In the first case, a 70-year-old man with iatrogenic UVFP received VFI with cross-linked HA three years ago and was referred for persistent dysphonia. Previously injected HA spilled out from the vocal fold (VF) when an epithelial incision was made in the subepithelial cystic lesion. In the second case, a 72-year-old woman with iatrogenic UVFP received VFI with cross-linked HA that migrated into the subepithelial space. Diffuse swelling of the injected VF caused dysphonia that lasted for a year. The previously injected HA spilled out when an epithelial incision was made in the swollen VF. Since superficially injected deep-volumizing cross-linked HA can persist for up to three years, laryngologists should be aware of possible sequelae upon suboptimal VFI with cross-linked HA.

Transcutaneous Laryngeal Ultrasound for Assessing Hyaluronic Acid Status in Patients Undergoing Injection Laryngoplasty

OBJECTIVE

Injection laryngoplasty (IL) with hyaluronic acid (HA) is an effective treatment for patients with glottic insufficiency. The duration of HA maintenance in the vocal fold remains unknown. In this study, transcutaneous laryngeal ultrasound (TLUS) was used to evaluate the absorption and migration of HA after IL. Subsequent management might be provided based on the TLUS finding.

METHODS

Patients diagnosed with unilateral vocal fold paralysis (UVFP) or vocal fold atrophy were recruited. All patients underwent IL with HA in an office-based setting along with TLUS to monitor the status of HA. The schedule of TLUS included assessments before and after IL until non-visualization.

RESULTS

The study population comprised 38 women and 17 men. Of the patients, 54.1% underwent IL for UVFP, whereas 45.9% underwent IL for vocal fold atrophy. Multivariate Cox regression analysis for factors affecting HA absorption revealed that the cause of injection was the most important independent predictor (hazard ratio [HR], 2.15; 95% confidence interval [CI], 1.03-4.46; p = 0.040). The duration of HA maintenance was significantly longer in patients with UVFP than in those with vocal fold atrophy (8.77 vs. 4.70 months, HR, 2.33; 95% CI, 5.47-8.18; p = 0.002).

CONCLUSION

TLUS is an objective assessment method for patients undergoing IL with HA. Subsequent tailor-made management could be offered based on the TLUS findings during follow-up. For patients at high risk of upper respiratory tract infection or who are intolerant to flexible nasopharyngoscopy, TLUS can be used as an alternative tool to evaluate the condition of the glottis after IL with HA.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:4682-4687, 2024.

Precision-Targeted Injection Laryngoplasty and Longitudinal Biomaterial Effects Evaluation Using High-resolution Ultrasonography in a Rat Model

OBJECTIVE

Current laryngeal injection models rely on the transoral route and are suboptimal due to limited view, narrowed working space, and the need to sacrifice animals for investigation of the injectables. In the present study, a novel surgical model for laryngeal intervention therapy utilizing an ultra-high frequency ultrasound imaging system was proposed. Based on this system, we developed a systemic evaluation approach, from guidance of the injection process, documentation of the injection site of the material, to in vivo longitudinal follow-up on the augmentation and medialization effect by analyzing the ultrasonography data.

STUDY DESIGN

In vivo animal study.

SETTING

Academic institution.

METHODS

Injection laryngoplasty with hyaluronic acid under ultrasonography guidance was performed on Sprague-Dawley rats one week after induced unilateral vocal paralysis. Ultrasonography was performed at preinjection, immediately postinjection, on Day 2, Day 7 and then weekly for 4 weeks to obtain measurements, including the glottic area, angle between bilateral folds, and vocal fold width ratio. Laryngoscopic and histologic studies were also performed.

RESULTS

Unilateral injections to the paralyzed fold were successfully performed as demonstrated by ultrasonographic, laryngoscopic, and histologic studies. The width ratio was significantly increased after injection for 4 weeks, while the glottic airway area was unchanged.

CONCLUSION

Here, a novel surgical model for laryngeal injection utilizing ultrasonography in rats was established. In addition to providing visual guidance for precise localization of the injection, robust documentation of the treatment effect was also demonstrated. This methodology could be beneficial for screening therapeutic agents for treatment of glottic insufficiency.

Trends in Injectable Biomaterials for Vocal Fold Regeneration and Long-Term Augmentation

Human vocal folds (VF), a pair of small, soft tissues in the larynx, have a layered mucosal structure with unique mechanical strength to support high-level tissue deformation by phonation. Severe pathological changes to VF have causes including surgery, trauma, age-related atrophy, and radiation, and lead to partial or complete communication loss and difficulty in breathing and swallowing. VF glottal insufficiency requires injectable VF biomaterials such as hyaluronan, calcium hydroxyapatite, and autologous fat to augment VF functions. Although these biomaterials provide an effective short-term solution, significant variations in patient response and requirements of repeat reinjection remain notable challenges in clinical practice. Tissue engineering strategies have been actively explored in the search of an injectable biomaterial that possesses the capacity to match native tissue's material properties while promoting permanent tissue regeneration. This review aims to assess the current status of biomaterial development in VF tissue engineering. The focus will be on examining state-of-the-art techniques including modification with bioactive molecules, cell encapsulation, composite materials, as well as, in situ crosslinking with click chemistry. We will discuss potential opportunities that can further leverage these engineering techniques in the advancement of VF injectable biomaterials.

Injectable Tissue Adhesive Microgel Composite Containing Antifibrotic Drug for Vocal Fold Scarring

Vocal fold (VF) scarring, a complex problem in laryngology, results from injury and inflammation of the layered architecture of the VFs. The resultant voice hoarseness, for which successful therapeutic options are currently limited, affects the patient's quality of life. A promising strategy to reverse this disorder is the use of antifibrotic drugs. The present study proposes a novel microbead-embedded injectable hydrogel that can sustain the release of the anti-fibrotic drug pirfenidone (PFD) for vocal fold scarring. Microbeads were developed using sodium alginate and gelatin, which were further embedded into a biomimetic and tissue adhesive gellan gum (GG) hydrogel. The microbead-embedded hydrogel exhibited improved injectability, viscoelasticity, tissue adhesiveness, degradability, and swelling compared to the hydrogel without beads. Additionally, the bead-embedded hydrogel could sustain the release of the PFD for a week. In vitro studies showed that the drug-loaded hydrogel could reduce the migration and proliferation of fibroblast cells in a dose-dependent manner. In summary, this study demonstrates the potential of a PFD-loaded injectable hydrogel with enhanced viscoelastic and tissue-adhesive properties for vocal fold scarring applications.

Additional injection laryngoplasty as a salvage treatment for unilateral vocal fold paralysis

OBJECTIVES

Injection laryngoplasty (IL) has been widely used as an initial treatment option for unilateral vocal fold paralysis (UVFP). An additional (second) IL is considered a salvage treatment for unsatisfactory outcomes of initial IL resulting from inadequate injection or early resorption of the injection material. This study aims to evaluate the efficacy of additional IL, distinguishing between "salvage" (within 4 months) and "repeated" injections (beyond 4 months), and to analyze prognostic factors for successful outcomes.

METHODS

This retrospective study involved patients who received IL at Asan Medical Center from January 2014 to December 2020. Voice parameters were collected after each procedure, and those who conducted the statistical analysis were blinded to the study subjects. Among the 65 patients who underwent additional IL, 51 patients were enrolled in this study. Postinjection grade, roughness, breathiness, asthenia, strain (GRBAS) scales were used to determine satisfactory treatment outcomes. Success of the additional IL was defined as a postinjection grade of dysphonia score of 0 or 1, with a reduction in grade compared with the preinjection grade.

RESULTS

The mean age of the patients was 61.6 years. Out of a total of 51 patients, 37 were men participating in the study. The odds ratio represents the likelihood of success in the second IL. Improved voice outcome after the additional IL was maintained in 23 (45%) patients. Compared with the failure group, the success group had a longer injection time interval between the initial and additional injection (9.1 vs. 7.4 months, respectively, p = 0.010). The success group had a higher proportion of patients with injection intervals >6 months (73.9% vs. 42.9%, p = 0.026). Logistic regression analysis revealed an injection interval >6 months had an odds ratio of 0.265 (confidence interval: 0.080-0.874, p = 0.029).

CONCLUSIONS

Additional injections would benefit the patients whose voice outcomes are maintained for a longer period (>6 months) after the first injection.

Ten-year outcomes of recurrent laryngeal nerve reinnervation for thyroidectomy-related unilateral vocal fold paralysis: A single-surgeon, prospective study

OBJECTIVES

This study evaluated the long-term outcomes of intraoperative recurrent laryngeal nerve (RLN) reinnervation for managing thyroidectomy-related unilateral vocal fold paralysis (UVFP) over a period of 10 years and assessed the long-term efficacy of this technique.

METHODS

This study was conducted between March 2006 and July 2022 at Soonchunhyang University Bucheon Hospital. We enrolled 25 patients who underwent RLN reinnervation via direct neurorrhaphy or ansa cervicalis-to-RLN anastomosis and completed subjective and objective voice measurements over 5 years period. Among these, 10 patients completed voice measurements over 10 years period.

RESULTS

Six months post-RLN reinnervation, most subjective voice parameters and some of objective voice parameters showed significant improvement (p < 0.05). Twelve months after the procedure, most parameters demonstrated significant voice improvements. These improvements remained stable in follow-up examinations 10 years post-RLN reinnervation (p < 0.05).

CONCLUSIONS

With stable voice outcomes over a decade, primary intraoperative RLN reinnervation provides satisfactory voice outcomes for 10 years postoperatively. Concerning the long-term survival of thyroid cancer patients, primary intraoperative RLN reinnervation is the first recommended voice rehabilitation technique for thyroidectomy related permanent UVFP.

Predominantly unilateral laryngomalacia in infants with unilateral vocal fold paralysis

BACKGROUND

Neonatal unilateral vocal fold paralysis may arise iatrogenically, idiopathically, or in the context of an underlying neurologic disorder. Management is often supportive, focusing on diet modification to allow for safe oral feeding. We describe the clinical course of six infants with unilateral vocal fold paralysis who developed predominantly unilateral laryngomalacia ipsilateral to the affected vocal fold with associated severe respiratory symptoms and feeding difficulty.

METHODS

Retrospective review of six infants with unilateral vocal fold paralysis and predominantly unilateral laryngomalacia. Charts were reviewed for etiology of vocal fold paralysis, presenting symptoms, operative details, postoperative course, and outcomes for breathing and swallowing.

RESULTS

Etiology of vocal fold paralysis included cardiac surgery in four patients, intubation-related in one, and idiopathic in one. Presenting symptoms included increased work of breathing, stridor, feeding difficulty, respiratory failure requiring noninvasive respiratory support, and weak cry. All infants were on nasogastric tube feedings. Direct microlaryngoscopy with unilateral or predominantly unilateral (conservative contralateral aryepiglottic fold division) supraglottoplasty was performed. Stridor and work of breathing improved in all six patients within 1 week postoperatively. Oral feeding improved in three patients within 2 weeks. Three patients had persistent feeding impairment with improvement within one year.

CONCLUSIONS

Predominantly unilateral laryngomalacia may arise in the context of unilateral vocal fold paralysis. Addressing the ipsilateral cuneiform collapse can improve breathing and feeding. This may be an under-described phenomenon and represents an additional reason to include the otolaryngologist early in the care of infants with suspected possible new unilateral vocal fold paralysis. Breathing and swallow can improve post-operatively, but feeding may remain limited by the vocal fold paralysis and any medical comorbidities. Ongoing follow-up and collaboration with speech-language pathology to optimize feeding are important.

Silk-Hyaluronic Acid for Vocal Fold Augmentation: Safety Profile and Long-Term Voice Outcomes

OBJECTIVES

Silk-hyaluronic acid (silk-HA) is a novel vocal fold augmentation material used in humans since July 2020. We aim to describe indications, voice outcomes, and longevity data for silk-HA injectable when used for vocal fold injection (VFI) augmentation in a large cohort of patients with longer-term follow-up than preliminary clinical studies.

METHODS

Retrospective chart review of Silk-HA injections for glottic insufficiency (GI) and follow-up between July 2020 and November 2023. Subject demographics, diagnoses, volume of material injected, VHI-10 data, time from injection, need for reinjection, and complications were collected. Blinded perceptual voice analysis of randomly selected pre- and post-intervention voice samples for unilateral vocal fold paralysis patients was performed by three voice-specialized speech-language pathologists, and changes in VHI-10 determined at various time intervals up to 1year and beyond.

RESULTS

A total of 160 silk-HA injection procedures were performed: 59% female, with a mean age of 66± 13 (range 21-90) years. Ninety-four subjects had unilateral paralysis (58.4%); the remainder had scar, atrophy, paresis, or a combination thereof. Mean volume of silk-HA injected was 0.24± 0.14 cc. Major complications were rare, most notable for laryngoscopic evidence of hemilaryngeal edema (n = 6, 3.8%), with a readmission rate to hospital of 1.3% (n = 2). There was a statistically significant decrease in paired ΔVHI-10 and CAPE-V ratings for each of the postoperative follow-up intervals. A total of 24 (27.2%) repeat medialization procedures were recommended following silk-HA injection for unilateral paralysis.

CONCLUSIONS

This study demonstrates that silk-HA is a safe product for VFI augmentation, and effective injectable for the treatment of GI due to unilateral vocal fold paralysis. Based on the current data, it is reasonable to counsel patients that they should expect benefit for several months following the injection. If patients reach 1year from their injection with a stable and satisfactory outcome, the majority experience ongoing benefit without need for additional procedures, however, the final duration of clinical effect appears to be years, but it is yet to be determined.

Laryngeal office-based procedures: A safe approach

PURPOSE

Laryngeal surgeries using a flexible nasopharyngoscope equipped with an operative channel has gained popularity, with gradual increase in the variety of interventional office-based procedures, under local anesthesia. The purpose of this study is to analyze the tolerance of such procedures.

MATERIALS AND METHODS

Retrospective cohort study. 337 cases were performed during 2 years. We collected the following data: type of pathology, type of procedure and modalities of anesthesia, adverse events.

RESULTS

19 % of the visits were for the purpose of Biopsy, 65 % for an injection, and Trublue Laser was utilized in 12 % of the procedures. Regarding the pathologies, 27 % were vocal fold paralysis, 18 % leukoplakia or another suspicious lesion, 15 % recurrent respiratory papillomatosis, 13 % neuromuscular disorder, 9 % vocal fold scarring, 7 % vocal cord atrophy and 6 % had an inflammatory presentation. Side effects were documented in 26 visits (7.7 %) and were minor in almost all the encounters: they included strong reflexive cough, deep throat pain, discomfort, gag reflex, anxiety, vagal discomfort, malaise, hypersalivation, nose pain, labile hypertension. More severe side effects were very rare and included septal wound and epistaxis, erythematous rash, dyspnea, and transient dysarthria. 13 procedures were either aborted, or canceled at initial steps, due to inability of the patient to tolerate the procedure and were rescheduled for general anesthesia. 97 % of the cases were released home after 1 h of surveillance.

CONCLUSION

Office-based flexible interventional laryngoscopy under local anesthesia is a safe and well-tolerated procedure, with abundance of various interventions feasible on ambulatory, office-based setup.

Outcomes of Injection Laryngoplasty for Deep Interarytenoid Groove

Introduction  Deep interarytenoid groove (DIG) may cause swallowing dysfunction in children; however, the management of DIG has not been established. Objective  We evaluated the subjective and objective outcomes of interarytenoid augmentation with injection in children with DIG. Methods  Consecutive children under 18 years of age who underwent injection laryngoplasty for DIG were reviewed. Data pertaining to demographics, past medical history, past surgical history, and results of pre and postoperative video fluoroscopic swallow study (VFSS) were obtained. The primary outcome measure was the presence of thin liquid aspiration or penetration on postoperative VFSS. The secondary outcome measure was caregiver-reported improvement of symptoms. Results  Twenty-seven patients had VFSS before and after interarytenoid augmentation with injection (IA). Twenty (70%) had thin liquid penetration and 12 (44%) had thin liquid aspiration before the IA. Thin liquid aspiration resolved in 9 children (45%) and persisted in 11 (55%). Of the 12 children who had thin liquid aspiration prior to IA, 6 (50%) had resolution of thin liquid aspiration after IA. Conclusions  Injection laryngoplasty is a safe tool to improve swallowing function in children with DIG. Further studies are needed to assess the long-term outcomes of IA and identify predictors of successful IA in children with DIG.

Efficacy of platelet-rich plasma (PRP) in benign vocal fold lesions: a systematic review and meta-analysis

OBJECTIVES

To evaluate the efficacy of platelet-rich plasma (PRP) in benign vocal fold lesions.

METHODS

MEDLINE, Cochrane Central, Web of Science, and Scopus databases were searched in April 2023 for relevant clinical trials. Inclusion criteria were clinical trials evaluating the efficacy of PRP in benign vocal fold lesions. We conducted a comparative double-arm analysis using the pooled mean difference (MD) and 95% confidence interval (CI). Outcomes of interest included the vocal handicap index (VHI), the Jitter and Shimmer percentages, and the noise-to-harmonic ratio (NHR).

RESULTS

Six studies matched the inclusion criteria. The pooled analysis shows that PRP was associated with significantly lower VHI scores compared with the control (MD = - 5.06, p < 0.01). Regarding the Jitter percentage, the PRP group was not superior to the control group at 2 and 4 weeks. However, the results revealed that PRP significantly reduced the Jitter percentage at 3 months (MD = - 0.61, p = 0.0008). The overall analysis favored the PRP arm significantly (p < 0.001). As for the Shimmer percentage, the combined effect estimate favored the PRP group (MD = - 1.22, p = 0.002). Subgroup analysis according to the time did not reveal any significant differences between studies at 2 weeks, 4 weeks, and 3 months. The analysis of the NHR outcome revealed a significant difference between both groups (MD = -1.09, p = 0.01). However, at 4 weeks, the treatment group had a significantly lower NHR % compared to the control group (MD = - 0.61, p = 0.02). There was no significant difference at 3 months (MD = - 2.14, p = 0.14).

CONCLUSIONS

Platelet-rich plasma is effective in reducing VHI scores, Jitter and Shimmer percentages, and NHR values. This effect is more evident after follow-up, especially 3 months.

Angles of Needle Insertion for True Vocal Fold Access Via the Thyrohyoid and Cricothyroid Membranes of the Larynx

OBJECTIVE

This study aims to provide an analysis of the cricothyroid and thyrohyoid membrane approaches for laryngeal injections in cadaveric vocal cords. The primary objective is to determine the optimal techniques, needle trajectories, and anatomical landmarks for accessing different regions of the vocal cords percutaneously.

MATERIALS AND METHODS

The study was conducted on 23 adult cadavers, consisting of 8 females and 15 males. The cadaveric larynges were mounted vertically to ensure proper anatomical positioning. Both the cricothyroid and thyrohyoid membrane approaches were utilized for reaching the vocal cords. Measurements were taken for needle trajectories, angles, and distances to determine the optimal approach for accessing the anterior, middle, and posterior thirds of the vocal cord.

RESULTS

Through the thyrohyoid membrane approach, the anterior, middle, and posterior thirds of the vocal cords can be accessed with the optimal needle insertion coronal angles of 15.46 ± 7.86°, 16.52 ± 7.15° and 18.29 ± 14.46°, and sagittal angles of 126.01 ± 9.65°, 116.67 ± 8.04° and 111.02 ± 8.86° respectively at a lateral distance of 1.92 ± 1.62 mm from the midline and 8.48 ± 2.73 mm below the vertical line. From the cricothyroid membrane approach, optimal coronal and sagittal insertion angles of the anterior, middle, and posterior thirds of the vocal cord were respectively: 158.95 ± 9.3°, 156.09 ± 11.59°, 152.4 ± 14.46°, 11.5 ± 7.77°, 21.83 ± 12.47° and 32.91 ± 12.59°.

CONCLUSION

This analysis of the cricothyroid and thyrohyoid membrane approaches in cadaveric larynges provides valuable insights for clinicians and researchers in the field of laryngology. The findings serve as a reference for optimizing laryngeal injection techniques, enhancing patient outcomes, and minimizing complications.

Systematic review and meta-analysis of laryngeal reinnervation techniques in adults with unilateral and bilateral vocal fold palsies

OBJECTIVE

To evaluate the outcomes of reinnervation techniques for the treatment of adult unilateral vocal fold paralysis and bilateral vocal fold paralysis.

METHODS

A literature review was conducted in the Embase and Medline databases in English, with no limitations on the publication date. The outcome parameters of interest included visual, subjective perceptual, acoustic, aerodynamic analysis and electromyography. A meta-analysis with a random-effects model and inverse variance was calculated.

RESULTS

The systematic Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach resulted in 27 studies, totalling 803 patients (747 unilateral cases and 56 bilateral cases). Thyroid cancer and/or surgery had caused unilateral vocal fold paralysis in 74.8 per cent of cases and bilateral vocal fold paralysis in 69.6 per cent of cases. Statistically significant improvements in patients were observed for voice, deglutition and decannulation (bilateral vocal fold paralysis). Meta-analysis of 10 reinnervation techniques was calculated for the maximum phonation time of 184 patients.

CONCLUSION

Reinnervation was shown to improve voice, swallowing and decannulation, but studies lacked control groups, limiting generalisability. Larger studies with controls are needed.

Sulcus Vocalis: Clinical and Surgical Aspects

OBJECTIVES

To analyze clinical, vocal, and videolaryngoscopic parameters, as well as the treatments of patients with sulcus vocalis.

METHODS

This is an observational study. The medical records of patients diagnosed with sulcus vocalis (type II or III) were selected and demographic data, vocal symptoms, videolaryngostroboscopies, vocal analyses (perceptual and acoustic), and maximum phonation time (MPT) were collected. The vocal parameters of patients who underwent microsurgery to treat the sulcus were compared before and after surgery.

RESULTS

Exactly 109 patients were diagnosed with sulcus; however, only 60 completed the inclusion criteria (39 women and 21 men), with a mean age of 45 years. Hoarseness and vocal fatigue were reported in 100% and 88% of cases, respectively. Laryngoscopy indicated a type II sulcus (90%), type III sulcus (10%), and an association of the sulcus with other benign lesions (23%), especially polyps. Perceptual evaluations indicated mild to moderate dysphonia, roughness and breathiness of the voice, mean MPT of 10 seconds, and high values of jitter, pitch perturbation coefficient, and soft phonation index (SPI). Twenty-two patients (14 women and 8 men) underwent sulcus microsurgery. The surgery promoted a decrease in the GRBAS scores, an increase in the MPT, and a decrease in the SPI; however, other acoustic parameters remained unchanged.

CONCLUSIONS

Patients with sulcus vocalis had mild to moderate dysphonia, in addition to voice roughness and breathiness and elevated fundamental frequency. Surgical treatment improved vocal parameters but maintained some degree of dysphonia, indicating incomplete restoration of vocal qualities.

Management of Implant Extrusion following Thyroplasty for Vocal Fold Paralysis: A Case Report

The most widely used laryngeal surgery technique for patients with vocal fold paralysis is medialization thyroplasty. Materials such as Gore-Tex, silastic, and hydroxyapatite are often used, and the most worrisome possible complication is extrusion of the implant. A 36-year-old female patient with a history of pediatric cardiac surgery was diagnosed with left vocal cord paralysis after an episode of upper respiratory infection with a working diagnosis of subclinical left vocal cord paralysis following cardiac surgery. She underwent medialization thyroplasty with a Gore-Tex implant under local anesthesia. On the 21st postoperative day, she presented with sudden-onset hoarseness and dysphagia due to Gore-Tex implant extrusion. The implant was removed and augmentation of the left vocal cord with adipose tissue was performed. Only 14 cases of Gore-Tex implant extrusion have been described in the literature so far. The aim of this case report was not only to show one possible complication when using a Gore-Tex implant but also to present fat augmentation as one of the solutions for revision medialization and salvage treatment, with sustained long-term results.

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

Objectives

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.

Study Design

Animal model.

Setting

Academic medical center.

Methods

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.

Results

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.

Conclusion

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.

Securing injection laryngoplasty with anti-reflux valve

BACKGROUND

Injection laryngoplasty (IL) is a common procedure performed by the laryngologist to treat glottal insufficiency. It can be performed under general anaesthesia (GA) or as an office-based procedure. One of the common problems faced during IL is the disconnection between the injection needle and injection material syringe due to high-pressure effect. This may lead to leakage of the injectates especially when injecting high-viscosity materials such as calcium hydroxylapatite (CaHa) or injecting through hard fibrotic scar of the vocal fold.

PURPOSE

Due to this recurring issue, we propose anti-reflux valve as a connector to link up these two devices. The function of anti-reflux valve is to ensure secure connection between these two devices and overcome the problem.

METHODS

The anti-reflux valve that can be used is NeutraClearTM needle-free connector EL-NC1000 or MicroClaveTM clear connector. In our practice, these anti-reflux valves are used together with Integra MicroFrance straight malleable injection needle (0.5 mm diameter, 250 mm length) for IL under GA. However, any other injection needle suitable for IL may also be used with these anti-reflux valves.

RESULTS

Our 3 years' experience has shown good outcome with no reported incidence of device detachment or leakage of injectates during IL procedure.

CONCLUSIONS

Anti-reflux valve is a readily available device in the operating theatre or clinic and only involve simple preparation prior to IL. It is beneficial as an added device in IL procedure.

Safety of Platelet-Rich Plasma Subepithelial Infusion for Vocal Fold Scar, Sulcus, and Atrophy

OBJECTIVE

To demonstrate the safety profile of platelet-rich plasma (PRP) as an injectable therapeutic for the treatment of vocal fold scarring and atrophy.

METHODS

Preliminary report on a prospective clinical trial of patients with vocal fold scar or atrophy undergoing unilateral vocal fold subepithelial infusion with autologous PRP. Enrolled patients underwent four subepithelial injections spaced 1 month apart. Adverse events were assessed peri and post-injection at each session. Patient-reported outcomes were collected at every visit using the Voice Handicap Index-10 (VHI-10) and Vocal Fatigue Index (VFI) questionnaires.

RESULTS

Twelve patients underwent unilateral vocal fold injection with autologous PRP prepared according to Eclipse PRP® system protocol. Forty-three injections were performed using a peroral or percutaneous approach. An average of 1.57 ± 0.4 cc (range 0.6-2.0 cc) injectate was used. All patients tolerated the procedure without difficulty or peri-procedural complications. The average duration of follow-up was 3.6 ± 1.8 months. No significant inflammatory reactions or adverse events were seen to date. There was statistically significant improvement in patient-reported outcomes at the 3 month follow up (n = 9) follow-up (mean ΔVHI-10 = 10.8, p < 0.001, mean ΔVFI = 18.9, p = 0.01, t test, paired two sample for means, two-tail). All nine patients who completed the series of four injections subjectively (yes/no) reported they were satisfied with the results.

CONCLUSION

This prospective study cohort demonstrated a favorable safety profile, with no adverse events or peri-procedural complications. Subjective improvements in vocal quality and reduction in vocal fatigue need to be clinically correlated with further study.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:647-653, 2023.

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.

Larynx proteomics after jellyfish collagen IL: Increased ECM/collagen and suppressed inflammation

Objectives/Hypothesis

Compare proteomic profiles of rabbit vocal folds (VFs) injected with micronized cross-linked jellyfish collagen "collagen Type 0" (MX-JC) against two clinical products for injection medialization laryngoplasty (IL).

Study Design

Animal model.

Methods

Left recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received (MX-JC) and adipose-derived stem cells (ADSCs), Group 2, MX-JC alone; Group 3, cross-linked hyaluronic acid; and Group 4, micronized acellular dermis. Animals were sacrificed at 4 and 12 weeks. Proteomic profiling of injected versus noninjected VFs by nano-liquid chromatography, tandem mass spectrometry, and reactome gene ontology analysis was performed.

Results

Overall, 37-61 proteins were found to be upregulated and 60-284 downregulated in injected versus non-injected VFs (>1.5 fold, false discovery rate-adjusted p < .05). Over-representation analysis (% of total) revealed top up-regulated pathways at 4 and 12 weeks, respectively: Group 1, keratan sulfate metabolism (46%) and cellular processes (29%); Group 2, extracellular matrix (ECM)/collagen processes (33%) and beta oxidation (39%); Group 3, cellular processes (50%) and energy metabolism (100%); and Group 4, keratan sulfate metabolism (31%) and inflammation (50%). Top downregulated pathways were: Group 1, Inflammation (36%) and glucose/citric acid metabolism (42%); Group 2, cell signaling (38%) and glucose/citric acid metabolism (35%); Group 3, keratan sulfate metabolism (31%) and ECM/collagen processes (48%); and Group 4, glucose/citric acid metabolism (33%) and ECM/collagen processes (43%).

Conclusions

MX-JC "collagen Type 0" upregulates pathways related to ECM/collagen formation and downregulates pathways related to inflammation suggesting that it is promising biomaterial for IL.

Level of Evidence

NA.

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

BACKGROUND

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.

OBJECTIVE

This study aims to understand the variations in provider preference and utilization of injectable materials for VFI.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

5 Laryngoscope, 133:1176-1183, 2023.

Liquid-type plasma-controlled in situ crosslinking of silk-alginate injectable gel displayed better bioactivities and mechanical properties

Silk is a promising biomaterial for injectable hydrogel, but its long-gelation time and cytotoxic crosslinking methods are the main obstacles for clinical application. Here, we purpose a new in situ crosslinking technique of silk-alginate (S-A) injectable hydrogel using liquid-type non-thermal atmospheric plasma (LTP) in vocal fold (VF) wound healing. We confirmed that LTP induces the secondary structure of silk in a dose-dependent manner, resulting in improved mechanical properties. Significantly increased crosslinking of silk was observed with reduced gelation time. Moreover, controlled release of nitrate, an LTP effectors, from LTP-treated S-A hydrogel was detected over 7 days. In vitro experiments regarding biocompatibility showed activation of fibroblasts beyond the non-cytotoxicity of LTP-treated S-A hydrogels. An in vivo animal model of VF injury was established in New Zealand White rabbits. Full-thickness injury was created on the VF followed by hydrogel injection. In histologic analyses, LTP-treated S-A hydrogels significantly reduced a scar formation and promoted favorable wound healing. Functional analysis using videokymography showed eventual viscoelastic recovery. The LTP not only changes the mechanical structures of a hydrogel, but also has sustained biochemical effects on the damaged tissue due to controlled release of LTP effectors, and that LTP-treated S-A hydrogel can be used to enhance wound healing after VF injury.

Stem cell therapy for vocal fold regeneration after scarring: a review of experimental approaches

This review aims at becoming a guide which will help to plan the experimental design and to choose adequate methods to assess the outcomes when testing cell-based products in the treatment of the damaged vocal folds. The requirements to preclinical trials of cell-based products remain rather hazy and dictated by the country regulations. Most parameters like the way the cells are administered, selection of the cell source, selection of a carrier, and design of in vivo studies are decided upon by each research team and may differ essentially between studies. The review covers the methodological aspects of preclinical studies such as experimental models, characterization of cell products, assessment of the study outcome using molecular, morphological and immunohistochemical analyses, as well as measuring the tissue physical properties. The unified recommendations to perform preclinical trials could significantly facilitate the translation of cell-based products into the clinical practice.

Real-time Light-guided Vocal Fold Injection via Cricothyroid Membrane in Unilateral Vocal Fold Paralysis: A Human Pilot Study

Objectives.

Vocal fold injection (VFI) via the cricothyroid (CT) membrane is used to treat various diseases affecting the vocal folds. The technical challenges of this technique are mainly related to the invisibility of the needle. Real-time light-guided VFI (RL-VFI) was recently developed for injection under simultaneous light guidance in the CT approach. Herein, we present the first clinical trial of RL-VFI, in which we investigated the feasibility and safety of this new technique in unilateral vocal fold paralysis (VFP).

Methods.

This prospective pilot study enrolled 40 patients, who were treated with RL-VFI for unilateral VFP between September 2020 and August 2021. Adverse events were monitored during the procedure and for 4 weeks postoperatively. The Voice Handicap Index-10, the GRBAS (grade, roughness, breathiness, asthenia, and strain) scale, aerodynamic studies, and acoustic analyses were evaluated to compare the voice improvement after 4 weeks with the baseline values.

Results.

The needle tip was intuitively identified by the red light. The mean procedure time was 95.6±40.6 seconds for the initial injection, while the additional injection required 79.2±70.5 seconds. The injection was performed under light guidance without additional manipulation after the needle reached the intended point. No acute or delayed adverse events were reported. Among the 40 patients, 36 completed voice analyses after 4 weeks. Subjective and objective voice parameters, including the Voice Handicap Index-10, GRBAS scale, maximum phonation time, mean expiratory airflow, fundamental frequency, jitter, shimmer, and noise-to-harmonics ratio improved significantly after RL-VFI (P<0.05), while the expiratory volume was maintained.

Conclusion.

RL-VFI is feasible and safe for treating patients with unilateral VFP. This technique is anticipated to improve the precision and safety of the CT approach in the treatment of unilateral VFP. This study provides a rationale for further structured clinical studies.

Injection laryngoplasty during transoral laser microsurgery for early glottic cancer: a randomized controlled trial

BACKGROUND

Transoral laser microsurgery is widely used for treating T1/T2 glottic cancers. Hyaluronic acid (HA) is commonly used in vocal cord augmentation. We investigated the impact of intra-operative injection laryngoplasty on voice outcomes in early glottic cancer.

METHODS

Twenty patients were randomized to the treatment group receiving HA injection to the vocal cord contralateral to the lesion; or the control group, receiving no injection. Patients had a Voice Handicap Index-10 (VHI-10) questionnaire and a Maximum Phonation Time (MPT) measurement preoperatively and at 3, 12 and 24 months post-operatively. Mean change in VHI-10 and MPT, compared to baseline and between time points, were compared. Survival estimates were calculated.

RESULTS

Mean VHI-10 scores improved over time amongst all patients. There were no changes in mean VHI-10 from pre-operative values to 3, 12 or 24 months post-operatively. There were no significant differences when comparing various timepoints between groups. There were no significant changes in MPT amongst the groups, or the time-points compared. Two-year overall survival was 91.7%; disease free survival was 80.9%; no difference in recurrence free survival was seen between the groups.

CONCLUSION

Subjective voice scores improved over time in both groups; there were no improvements in VHI-10 or MPT scores in the injection group, over control, at any time points. We saw no significant impact for intra-operative HA injection laryngoplasty on subjective or objective voice outcomes following surgery for early glottic cancers.

Comparison of 24-month voice outcomes after injection laryngoplasty with calcium hydroxylapatite or hyaluronic acid in patients with unilateral vocal fold paralysis

PURPOSE

The objective was to evaluate the long-term voice outcomes in pa-tients with unilateral vocal fold paralysis treated with injection laryngoplasty using either cal-cium hydroxylapatite (CaHA) or hyaluronic acid (HA).

METHODS

A single-centre retrospective study was performed. There were 75 patients with dysphonia due to unilateral vocal fold paralysis: injected with CaHA or injected with HA. We analysed Voice Handicap Index-30 (VHI), videostroboscopic images, auditory-perceptual (GRBAS), and acoustic measures (MDVP) in 6, 12, and 24 months after augmentation.

RESULTS

The mean change in VHI 24 months after augmentation was 29.14 in the CaHA group, and 22.88 in the HA group. There was an improvement of glottal gap 6, 12, and 24 months after augmentation in both groups. The GRBAS parameters were similar in both groups throughout the whole period. The MDVP pa-rameters decreased 6 and 12 months after augmentation and were similar in both groups. There were 4 patients augmented with CaHA (12.5%) who needed reintervention within 2 years of surgery and another 4 (9.3%) augmented with HA.

CONCLUSION

This study demonstrates that there are no long-term differences in voice outcomes or number of reaugmentations for injection laryn-goplasty with CaHA compared to HA.

Objective Laryngoscopic Measures From Older Patients With Voice Complaints and Signs of Aging

PURPOSE

The purpose of this study was to use objective measures of glottal gap, bowing, and supraglottic compression from selected images of laryngoscopic examinations from adults over 60 years of age with voice complaints and signs of aging to test current hypotheses on whether degree of severity impacts treatment recommendations and potential follow-through with treatment.

METHOD

Records from 108 individuals 60 years or older with voice complaints and signs of aging were reviewed. Three objective measures (normalized glottal gap area [NGGA], total bowing index, and normalized true vocal fold width) were derived. Each measure was subsequently divided into three categories by severity: absence, small degree, or large degree. Nonparametric statistics tested associations between severity and treatment recommendations as well as potential follow-through.

RESULTS

Noninvasive treatments (observation/voice therapy) were marginally associated with no glottal gap (p = .09). More invasive treatments (injection/bilateral thyroplasty) were associated with glottal gaps being present (p = .026), but bilateral thyroplasty recommendations were not significantly associated with the largest gaps. Treatment modalities were not characterized by specific severity categories for any of the objective measures. No significant differences were found for any of the three objective measures between those who followed through with recommended treatment and those who did not.

DISCUSSION

Results demonstrated some support for current hypotheses on how degrees of severity of objective measures relate to treatment recommendations. Of the three measures, NGGA appears to be more informative regarding treatment recommendations and follow-through, but due to low power, larger sample sizes are needed to confirm clinical relevance.

Respiratory and voice outcomes of office-based injection laryngoplasty in patients with unilateral vocal fold paralysis

Background

Injection laryngoplasty is a surgical procedure used in management of glottal insufficiency. The objective of this study was to assess respiratory and voice outcomes of office-based injection laryngoplasty in patients with unilateral vocal fold paralysis (UVFP). Ten patients underwent office-based injection via transcutaneous approach using Radiesse or hyaluronic acid. Auditory perceptual assessment (APA), voice handicap index (VHI), size of the glottic gap, acoustic parameters (jitter, shimmer, and harmonic to noise ratio), maximum phonation time (MPT), stroboscopic evaluation, pulmonary function tests (PFTs), and videofluoroscopic evaluation of swallowing were done pre-injection, 1 week and 3 months post-injection.

Results

Subjective and objective voice outcomes, in addition to laryngostroboscopic parameters improved after injection. Non-significant difference was found between pre- and post-injection results of the PFTs.

Conclusions

Office-based injection laryngoplasty is a safe and effective method for treating UVFP. Patients with glottic gap (< 1–3 mm) are perfect candidates for such procedure. Injection laryngoplasty improves patients’ voice quality and does not impair respiration.

Postoperative Pharynx and Larynx

Cancers of the pharynx and larynx are treated using a combination of chemotherapeutic, radiation, and surgical techniques, depending on the cancer type, biology, location, and stage, as well as patient and other factors. When imaging in the postsurgical setting, the knowledge of the type of tumor, preoperative appearance, and type of surgery performed is essential for accurate interpretation. Surgical anatomic changes, surgical implants/devices, and potential postsurgical complications must be differentiated from suspected recurrent tumors.

Adverse events following injection laryngoplasty: An analysis of the MAUDE database

OBJECTIVE

Injection laryngoplasty (IL) is considered safe in both the operating room and clinical setting. However, safety data is limited to single-institution studies with reduced sample sizes. The objective of this study is to examine a national database for adverse events related to IL in an effort to further confirm the safety of this procedure and better characterize potential complications.

MATERIALS AND METHODS

Retrospective analysis of the Manufacturer and User Facility Device Experience (MAUDE) database for reported adverse events of IL procedures utilizing calcium hydroxyapatite (CAHA), hyaluronic acid (HA) and carboxymethylcellulose (CMC) implants from 2009 to 2020.

RESULTS AND ANALYSIS

We identified 47 reported adverse events. The average patient age was 54 years old. 59.3% of patients were female. Adverse events more frequently involved the use of CAHA compared to HA or CMC (n = 27, 57.4%, n = 13, 27.7% and n = 7, 14.9%, respectively). The most common adverse events were laryngeal edema (n = 18, 39.1%), improper placement of injected material (n = 12, 26.1%), persistent dysphonia (n = 13, 28.3%), and post-injection dysphagia or odynophagia (n = 11, 23.9%). Major events, defined as requiring emergency room treatment, hospitalization, or surgical intervention accounted for 29 (60.4%) of cases. Four cases of edema required intubation, and one patient necessitated a surgical airway.

CONCLUSION

Complications arising from IL range from minor events to airway obstruction and may happen with a variety of injectable materials including CAHA, HA and CMC. Few cases of airway obstruction requiring immediate intervention were identified, confirming the safety of IL in both the operative and office setting.

Autologous Fat Injection Laryngoplasty for Unilateral Vocal Fold Paralysis

BACKGROUND

Unilateral vocal palsy (UVFP) affects the voice and swallowing function and could be treated by various materials to achieve improved mucosal wave and better closure during phonation. Injection laryngoplasty is considered an exemplary method for these patients and could be injected as early as possible. We conducted a systematic review and meta-analysis for the subjective and objective outcomes of autologous fat injection laryngoplasty (AFIL) and assessed the effects for patients with UVFP.

METHODS

We searched studies from PubMed and EBSCO databases with PRISMA appraisal to search for articles about the effects of AFIL on UVFP. The published articles were reviewed according to our inclusion and exclusion criteria. The short- and long-term outcomes of perceptual, acoustic analysis, and quality of life were also analyzed by meta-analysis.

RESULTS

Eleven articles were reviewed, and seven studies were selected for meta-analysis. AFIL improves the perceptual outcome and some voice parameters in short-term and long-term results, i.e., jitter, shimmer, and maximal phonation time (MPT). It also significantly improved the voice handicap index (VHI) in the long term, suggesting an increase in quality of life.

CONCLUSIONS

AFIL is considered a reliable treatment method for UVFP and could even last for over 12 months.

Autologous Adipose Tissue Injection of Vocal Cords in Presbyphonia

OBJECTIVE

This series evaluates the long-term results of autologous adipose injection (AAI) in patients older than 65 years with presbyphonia.

STUDY DESIGN

Retrospective cohort study.

SETTING

Academic secondary medical center.

METHODS

This was a retrospective study with a minimum follow-up of 12 months. All patients underwent AAI for atrophy of both vocal folds due to presbyphonia. We measured subjective parameters as Voice Handicap Index-10 (VHI-10) or GRBAS scale (grade, roughness, breathiness, asthenia, strain) and objective measures such as maximum phonation time (MPT) or square pixel closure defect. We reviewed the medical records of patients undergoing AAI during the 2011-2018 period. An analysis of the demographic variables of the group was performed, as well as the values of VHI-10, GRBAS, and MPT, and the minimum closure defect measured in square pixels and the number of closed frames in the glottal cycle before and after the intervention.

RESULTS

At 12 months, 17 of 18 patients reported subjective and VHI-10 improvement. The mean preoperative VHI-10 (26.7) was significantly higher than the postoperative value (14.4), and the GRBAS scale had a preoperative mean of 8.7 and a postoperative mean of 4.3, both with statistical significance. MPT increased from 7.7 to 12.4 seconds (P < .0001). The minimum closure defect measurements obtained in square pixels changed from 305 to 124, achieving complete closure in 3 patients. The closed phase of the glottal cycle change from 14.3% to 38.2% after the AAI.

CONCLUSIONS

AAI improves long-term vocal fold closure, demonstrating utility in patients with presbyphonia.

In Vitro Evaluation of Biomaterials for Vocal Fold Injection: A Systematic Review

Vocal fold injection is a preferred treatment in glottic insufficiency because it is relatively quick and cost-saving. However, researchers have yet to discover the ideal biomaterial with properties suitable for human vocal fold application. The current systematic review employing PRISMA guidelines summarizes and discusses the available evidence related to outcome measures used to characterize novel biomaterials in the development phase. The literature search of related articles published within January 2010 to March 2021 was conducted using Scopus, Web of Science (WoS), Google Scholar and PubMed databases. The search identified 6240 potentially relevant records, which were screened and appraised to include 15 relevant articles based on the inclusion and exclusion criteria. The current study highlights that the characterization methods were inconsistent throughout the different studies. While rheologic outcome measures (viscosity, elasticity and shear) were most widely utilized, there appear to be no target or reference values. Outcome measures such as cellular response and biodegradation should be prioritized as they could mitigate the clinical drawbacks of currently available biomaterials. The review suggests future studies to prioritize characterization of the viscoelasticity (to improve voice outcomes), inflammatory response (to reduce side effects) and biodegradation (to improve longevity) profiles of newly developed biomaterials.

Effects of percutaneous injection laryngoplasty on voice and swallowing problems in cancer-related unilateral vocal cord paralysis

BACKGROUND

Unilateral vocal cord paralysis may result from nerve compression by tumors or direct nerve injuries during tumor resections, which can cause dysphonia or dysphagia, and reduced quality of life.

OBJECTIVES

This prospective, single-group study aimed to investigate the effect of percutaneous injection laryngoplasty on voice and swallowing function in patients with cancer-related unilateral vocal cord paralysis.

METHODS

Patients underwent percutaneous injection laryngoplasty with hyaluronic acid under local anesthesia. Stroboscopy and videofluoroscopic swallowing study were conducted to evaluate the voice- and swallowing-related outcome measures, respectively. The participants were evaluated before injection laryngoplasty, as well as after two weeks and three months.

RESULTS

Injection laryngoplasty significantly improved the glottal gap, vocal fold position, Maximum Phonation Time, and Voice Handicap Index-10. Post-hoc analysis using Bonferroni correction showed that the improvements occurred within two post-treatment weeks and remained at three post-treatment months. In the subgroup analysis, the patients who underwent injection laryngoplasty within 8 weeks from onset showed significantly higher improvements in the videofluoroscopic dysphagia scale and swallowing function than the patients who received the procedure after 8 weeks or more.

CONCLUSION

Percutaneous injection laryngoplasty improves glottal closure and voice in patients with cancer-related unilateral vocal cord paralysis. Early injection laryngoplasty may lead to greater benefits on swallowing function.

LEVEL OF EVIDENCE

4.

Vocal fold injection material does not preclude interpretation of laryngeal electromyography

INTRODUCTION/AIMS

Temporary vocal fold injection (VFI) is a common treatment for acute and subacute vocal fold paralysis (VFP). Laryngeal electromyography (LEMG) is useful for diagnosing neurogenic causes of VFP. This study evaluated whether the presence of VFI material prevents interpretation of LEMG in patients with acute and subacute VFP.

METHODS

Patients with acute and subacute unilateral VFP (onset ≤6 mo) who underwent temporary VFI within 3 mo preceding LEMG were evaluated. A matched control group that did not undergo VFI was also studied. The LEMG team (laryngologist and electromyographer) performed and interpreted LEMG using a pre-specified protocol, including qualitative and quantitative motor unit analysis.

RESULTS

Eighteen patients with VFI underwent LEMG successfully with interpretation of spontaneous activity and motor unit recruitment. Fourteen patients were seen in follow-up to determine accuracy of established LEMG prognosis. Seven of seven subjects with poor LEMG prognosis did not recover vocal fold motion. Five of seven subjects with fair LEMG prognosis recovered vocal fold motion. Findings were similar for the control group.

DISCUSSION

VFI augmentation material did not prevent interpretation of meaningful LEMG data in patients with acute and subacute VFP, and accurate prognoses of vocal fold motion recovery were established.

Vocal Fold Injection Augmentation for Post-Airway Reconstruction Dysphonia: A Case Series

OBJECTIVES

Post airway reconstruction dysphonia (PARD) is common and has a significant effect on the quality of life of patients. Vocal fold injection augmentation (VFIA) is one treatment that can be used to improve glottic insufficiency in some patients. The goal of this study was to characterize the use and outcomes of VFIA for PARD.

METHODS

Retrospective chart review from January 2007 to July 2018 at a tertiary pediatric care center. Consecutive patients with PARD who underwent VFIA, who had a preoperative voice evaluation and a follow-up evaluation within 3 months after VFIA (fat, carboxymethylcellulose gel, hyaluronic acid).

RESULTS

Thirty-four patients (20 female) underwent VFIA. The mean age at the time of the injection was 13.6 years (SD 6.1). Twenty patients (58.8%) had a history of prematurity and a mean of 1.8 open airway surgeries. After injection, 29/34 patients (85.3%) noted a subjective voice improvement. The baseline Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) overall severity score decreased by a mean of 5.7 (SD = 19.6) points, P = .12. Total pediatric Voice Handicap Index (pVHI) improved by 6.0 (SD = 19.5) points, from 57.4 (SD = 20.0) to 51.4 (SD = 17.2), P = .09. Functional pVHI subscore demonstrated a significant improvement, with a decrease of 3.4 (SD = 7.3) points, P = .02. All procedures were performed as an overnight observation and no complication occurred.

CONCLUSION

Patients with PARD represent a complex subset of patients. VFIA is a straightforward intervention that may improve voice perception. Many patients reported subjective improvement despite minimal objective measurement. Further work is warranted to elucidate the role of injection in management of PARD.

MRI Study of Jellyfish Collagen, Hyaluronic Acid, and Cadaveric Dermis for Injection Laryngoplasty

OBJECTIVES/HYPOTHESIS

Test a new jellyfish collagen biomaterial aimed to increase duration of injection medialization laryngoplasty (IL) against two products in clinical practice.

STUDY DESIGN

Animal model.

METHODS

Left recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received micronized cross-linked jellyfish collagen (MX-JC) and adipose derived stem cells (ADSCs), Group 2, MX-JC alone, Group 3, cross-linked hyaluronic acid (X-HA), and Group 4, micronized acellular dermis (MACD). Animals were sacrificed at 4 and 12 weeks. Major outcomes were MRI tissue volumes and histopathology.

RESULTS

After 100 μL IL MRI volumes (means ± STD) at 4 and 12 weeks were: Group 1: 27.2 ± 15.6 and 13.1 ± 5.2 μL, Group 2: 60.8 ± 18 and 27.8 ± 2.47 μL, Group 3: 27.4 ± 12 and 10.6 ± 8 μL, and Group 4: 37.5 ± 11 and 9.85 ± 1 μL. Group 2 volumes were largest and Group 3 were smallest in all comparisons (P < .05). Histologically, low grade inflammatory responses were observed in Group 1, mild histiocytic infiltration in Group 2, widespread muscle fiber loss in Group 3, and plasmocytic infiltration in Group 4.

CONCLUSIONS

MX-JC showed the least resorption at 4 and 12 weeks among all groups. T cell inflammatory responses were observed with MX-JC but were reduced by 12 weeks while B cell immune responses, indicative of antibody priming, were predominantly noted with MACD. MX-JC + ADSC showed low grade immunity while the XHA showed greater myocyte loss compared to the other groups.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E2452-E2460, 2021.

In vivo vocal fold augmentation using an injectable polyethylene glycol hydrogel based on click chemistry

It is important to focus on urgent needs in clinics and develop optimal materials. For successful augmentation of vocal folds, the ideal filler should be injectable through a syringe, and should stably maintain its volume for a long time without toxicity. To achieve these criteria, a click chemistry-based PEG (polyethylene glycol) hydrogel was developed and applied for vocal fold augmentation in vivo. The PEG hydrogel enables fast gelation in vivo after injection and provides long-term stability. Azide- and dibenzocyclooctyne (DBCO)-modified 4-arm PEG were cross-linked by chemical conjugation via click chemistry and yielded gelation within several minutes. After subcutaneous injection into mice and rats, the PEG hydrogel showed higher stability after 1 month compared to the traditionally used calcium hydroxyapatite-carboxymethyl cellulose (CaHA-CMC) filler. In rabbit models with vocal fold paralysis, the PEG hydrogel stably fixed the paralyzed vocal fold in 4 months and minimized the glottic gap. It was an improved therapeutic result compared to CaHA-CMC, demonstrating the potential of a click chemistry-based PEG hydrogel for vocal fold therapy.

A proposal for needle projections in transcutaneous injection laryngoplasty using three-dimensionally reconstructed CT scans

PURPOSE

This study aims to determine laryngeal dimension in relation to all three transcutaneous injection laryngoplasty (TIL) approaches (thyrohyoid, transthyroid and cricothyroid) using three-dimensionally reconstructed Computed Tomography (CT) scan and compare the measurements between sex, age group and ethnicity.

METHODS

CT scans of the neck of two hundred patients were analysed by two groups of raters. For thyrohyoid approach, mean distance from the superior border of the thyroid cartilage to the laryngeal cavity (THd) and mean angle from the superior border of the thyroid cartilage to mid-true cords (THa) were measured. For transthyroid approach, mean distance from mid-thyroid cartilage to mid-true cords (TTd) and Hounsfield unit (HU) at mid-thyroid cartilage (TTc) were measured. For cricothyroid approach, mean distance from the inferior border of the thyroid cartilage to the laryngeal cavity (CTd) and mean angle from the inferior border of the thyroid cartilage to mid-true cords (CTa) were measured.

RESULTS

There were statistically significant differences between males and females for all measurements except for CTa (p < 0.0001). No significant difference across age groups and ethnicities were found for all three approaches (p > 0.05). There was a significant fair positive correlation between age and TTc (p = 0.0002). For all measurements obtained, there were moderate to excellent inter-group consistency and intra-rater reliability.

CONCLUSION

This study demonstrated a significant sex dimorphism that may influence the three TIL approaches except for needle angulation in the cricothyroid approach. The knowledge of laryngeal dimension is important to increase success in TIL procedure.

Fibrin Gel Suspended Autologous Chondrocytes as Cell-based Material for long-term Injection Laryngoplasty

OBJECTIVES/HYPOTHESIS

Injection laryngoplasty of materials for unilateral vocal-fold paralysis has shown various results regarding the long-term stability of the injected material. We evaluated a fibrin-gel based cell suspension with autologous chondrocytes in-vitro and in-vivo as long-term-stable vocal-fold augmentation material in an animal model.

STUDY DESIGN

This study compises an in vitro cell-culture part as well as an in vivo animal study with New Zealand White Rabbits.

METHODS

In in-vitro experiments, auricular chondrocytes harvested from 24 New Zealand White Rabbits cadavers were cultivated in pellet cultures to evaluate cartilage formation for 4 weeks using long-term-stable fibrin gel as carrier. Injectability and injection volume for the laryngoplasty was determined in-vitro using harvested cadaveric larynxes. In-vivo 24 Rabbits were biopsied for elastic cartilage of the ear and autologous P1 cells were injected lateral of one vocal cord into the paraglottic space suspended in a long-term-stable fibrin gel. Histologic evaluation was performed after 2, 4, 12, and 24 weeks.

RESULTS

During 12-week pellet culture, we found extracellular matrix formation and weight-stable cartilage of mature appearance. In-vivo, mature cartilage was found in two larynxes (n = 6) at 4 weeks, in four (n = 6) at 12 weeks, and in five (n = 6) at 24 weeks mostly located in the paraglottic space and sometimes with spurs into the vocalis muscle. Surrounding tissue was often infiltrated with inflammatory cells. Material tended to dislocate through the cricothyroid space into the extraglottic surrounding tissue.

CONCLUSIONS

A cell-based approach with chondrocytes for permanent vocal-fold augmentation has not previously been reported. We have achieved the formation of structurally mature cartilage in the paraglottic space, but this is accompanied by difficulties with dislocated material, deformation of the augmentation, and inflammation.

LEVEL OF EVIDENCE

N/A Laryngoscope, 131:E1624-E1632, 2021.

Real-Time Light-Guided Vocal Fold Injection: An In Vivo Feasibility Study in a Canine Model

Objectives

The transcutaneous approach is a good option for office-based vocal fold injection (VFI). However, precise localization requires extensive experience because the needle tip is invisible in small and complex laryngeal spaces. Recently, real-time light-guided VFI (RL-VFI) was proposed as a new technique that allows simultaneous injection under precise needle localization by light guidance. Herein, we aimed to verify the feasibility of RL-VFI in an in vivo canine model and explored its clinical usefulness.

Methods

The device for RL-VFI comprised a light source (light-emitting diode modules [10 W] of red color [650 nm]) and injectors (1.5 inches, 23 gauge). An adult male beagle was used for the experiment. After tracheostomy, a rigid laryngoscope was inserted and suspended to expose the larynx. A flexible naso-laryngoscopy system was used to visualize the vocal folds.

Results

RL-VFI was performed using various transcutaneous approaches, including the cricothyroid, transthyroid, and transhyoid approaches. Light guidance helped identify the path of the needle and prevent inadvertent penetration. The location of the needle tip was accurately indicated by the light. The illuminated needle could be easily placed at the intended points in the vocal fold with real-time visual-motor feedback. Hyaluronic acid could be simultaneously injected lateral to the vocal process under light guidance without manipulation of the device.

Conclusion

RL-VFI was found to be safe and feasible in an in vivo canine model, providing precise localization and visual-motor feedback. The clinical application of RL-VFI is expected to improve the safety and precision of VFI.