Vocal Fold Injection Research Articles

Salvage Treatments for Poor Voice Outcomes Following Autologous Fat Injection Laryngoplasty.

Fat injection laryngoplasty (FIL) is a common procedure used to correct glottic insufficiency. Nevertheless, few studies have discussed potential treatments for cases with poor voice recovery after FIL. Eighteen patients with unfavorable vocal outcomes from FIL were analyzed. Each of these patients presented persistent dysphonia for more than 2 months following FIL, together with bulging vocal folds and poor mucosal wave. We applied microsurgery as the standard treatment to remove excessive fat. Vocal fold steroid injection (VFSI) was administered to patients that were hesitant or declined to undergo microsurgery. Voice outcomes were evaluated using the Voice Handicap Index-10 (VHI-10), grade-roughness-breathiness (GRB) scores, and smoothed cepstral peak prominence (CPPs). Six patients underwent microsurgery directly, 6 patients received only VFSIs as a salvage treatment, and the remaining 6 patients received 1 to 3 courses of VFSIs before the decision to undergo microsurgery. Pathology reports were available for 10 patients, and contained 5 instances of adipose tissues, 3 of fat necrosis, 1 of chronic inflammation, and 1 of fibrosis. Seventeen patients reported satisfactory or improved outcomes. We found remarkable improvements in VHI-10, GRB, and CPPs (all P < .05) after salvage treatments for FIL. Subgroup analyses showed comparable voice outcomes for patients undergoing direct microsurgery, VFSI alone, and VFSI followed by microsurgery (P > .05). This study demonstrated that fat overinjection and/or fibrotic change in the injected vocal folds may cause poor voice outcomes after FIL. Both microsurgery and VFSI could be applied as salvage treatments with good voice recovery profiles. Level 4.

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.

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.

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

To demonstrate the safety profile of platelet-rich plasma (PRP) as an injectable therapeutic for the treatment of vocal fold scarring and atrophy. 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. 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. 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. 4 Laryngoscope, 133:647-653, 2023.

Long-term results and safety of fibroblast growth factor injection for unilateral vocal fold paralysis.

ObjectivesTreatments for unilateral vocal fold paralysis (UVFP) include conservative voice rehabilitation, vocal fold injection, and laryngeal framework surgery. We proposed basic fibroblast growth factor (bFGF) injection as a potential novel treatment for UVFP and have reported the short‐term results. In this study, we present the long‐term results and safety of vocal fold bFGF injection as a treatment for UVFP.MethodsThis retrospective study included 42 patients (25 males and 17 females) with UVFP who were administered a local injection of bFGF. The injection regimen involved injecting FGF (0.5 μg/ml in 0.5 ml per side) into the bilateral vocal folds using a 23‐gauge injection needle. Phonological outcomes were evaluated 6 months and 12 months after the injection.ResultsOverall, 26 patients received a single injection of bFGF, six patients received an additional injection, and 10 patients received the additional framework surgery. Maximum phonation time, mean flow rate, pitch range, jitter and shimmer percentages, the total GRBAS (grade, roughness, breathiness, asthenia, strain) score, and voice handicap index scores improved significantly in the long term. In patients who received the additional injection or framework surgery, the effects of bFGF injection were temporary, but did not interfere with the performance of the framework surgery.ConclusionIn total, 42 patients who underwent vocal fold bFGF injections were reviewed. The bFGF injections were effective and safe in the long‐term results for UVFP in the selected cases. Some patients with severe symptoms benefited from the additional framework surgery but not the additional bFGF injection.

Development and Clinical Application of Real-Time Light-Guided Vocal Fold Injection

Vocal fold injection (VFI) is widely accepted as a first line treatment in treating unilateral vocal fold paralysis and other vocal fold diseases. Although VFI is advantageous for its minimal invasiveness and efficiency, the invisibility of the needle tip remains an essential handicap in precise localization. Real-time light-guided vocal fold injection (RL-VFI) is a novel technique that was developed under the concept of performing simultaneous injection with precise placement of the needle tip under light guidance. RL-VFI has confirmed its possibility of technical implementation and the feasibility in injecting the needle from various directions through ex vivo animal studies. Further in vivo animal study has approved the safety and feasibility of the procedure when various transcutaneous approaches were applied. Currently, RL-VFI device is authorized for clinical use by the Ministry of Food and Drug Safety in South Korea and is clinically applied to patients with safe and favorable outcome. Several clinical studies are currently under process to approve the safety and the efficiency of RL-VFI. RL-VFI is expected to improve the complication rate and the functional outcome of voice. Furthermore, it will support laryngologists in overcoming the steep learning curve by its intuitive guidance.

Real-Time Light-Guided Vocal Fold Injection via the 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.

The impact of COVID-19 on otolaryngology research: a cross-sectional analysis of discontinued trials.

The COVID-19 pandemic has reduced the capacity to conduct medical research due to recruitment difficulties, supply chain shortages, and funding deficits. The clinical practice of otolaryngology was especially impacted due to a reduction in elective procedures, such as facial plastic surgeries and vocal fold injections. The primary objective was to examine the extent of clinical trial (CTs) disruption secondary to the COVID-19 pandemic in the field of otolaryngology. On August 1, 2021, we conducted a systematic search utilizing ClinicalTrials.gov for CTs related to common otolaryngology disorders. We utilized the date range January 1, 2020 through August 1, 2021 to identify all trials potentially affected by the COVID-19 pandemic. Investigators performed screening and data extraction in a duplicate, masked fashion. Trials resulting from the search were extracted for trial status, condition treated, enrollment number, funding, study type, study design, last update posted date, and trial location. Trials that explicitly mentioned COVID-19 as a reason for discontinuation or suspension were coded as such. For trials that did not explicitly mention COVID-19, we coded the reason provided from ClinicalTrials.gov. The Oklahoma State University Center for Health Science Institutional Review Board determined that this project did not qualify as human subject research. A total of 1,777 CTs met the inclusion criteria, and 223 CTs were discontinued between January 1, 2020 and August 1, 2021. Thirty-three (14.8%) of the 223 CTs reported discontinuation explicitly due to the COVID-19 pandemic. The 33 studies had 1,715 participants enrolled in total. Among the primary interventions, 11 (33.3%) were devices, 10 (30.3%) were drugs, 5 (15.2%) were behavioral, 4 (12.1%) were diagnostic tests, 1 (3.0%) was dietary, and 2 (6.1%) were labeled as "other." Regarding the CT location, 20 (60.6%) were conducted in the United States, and 13 (39.4%) were conducted internationally. Of the 33 CTs, 19 (57.6%) were suspended, 9 (27.3%) were terminated, and 5 (15.2%) were withdrawn. The overall most common reason for trial disruption was recruitment difficulties (24.2%). Median enrollment for discontinued trials due to COVID-19 was 37 (interquartile range [IQR], 19-71) and for other reasons was 6 (IQR, 0-27), for which the Mann-Whitney test showed a statistically significant difference between the two (z=-3.913, p<0.001). There were no significant associations between trial location, funding source, randomization, or whether a study involved masked vs unmasked participants. The COVID-19 pandemic has incited an impact on clinical research in the field of otolaryngology. To preserve trial continuation amid future threats to participant interaction and communication, we recommend further exploration of remote monitoring practices and virtual procedures-those that will maintain the effectiveness and accuracy needed to establish novel therapeutics. We encourage future trials to gauge which remote assessments show the greatest validity, with the long-term goal of establishing innovative study designs resilient to future pandemics.

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.

Comparison of therapeutic effects of steroid injection by benign vocal fold lesion type

Background Benign vocal fold lesions (BVFLs) can cause voice changes, including reduced loudness and pitch range. In recent times, with progression in endoscopic technology, office-based vocal fold steroid injection (VFSI) has been used as an alternative therapy for BVFLs. Aims/objectives In this study, we analyzed the efficacy and safety of VFSI to investigate the mechanism underlying its therapeutic effects and determine the conditions in which VFSI will be most effective. Materials and methods In this retrospective cohort study, we included 40 condition-matched patients (8 patients per lesion) with chorditis, vocal nodules, vocal polyps, Reinke’s edema (RE), or vocal scars who received similar regimens of steroid injection using a commercial preparation of triamcinolone acetonide. Their phonological outcomes were evaluated 2 or 3 months after the injection. Results Significant improvements were observed in Voice Handicap Index scores, results of laboratory voice evaluation, and voice quality measured using the Grade, Roughness, Breathiness, Asthenia, Strain scale in all participants. In subgroup analysis, VFSI was highly effective against chorditis and vocal nodules, but less effective against RE and vocal scars. Conclusions Single-dose VFSI is valuable as an alternative to voice rehabilitation and laryngo-microsurgery, but higher concentrations or repeated injections are required for intractable lesions.

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.

Pediatric Unilateral Vocal Fold Immobility.

Vocal fold immobility in children can affect breathing, swallowing, and speech function. Although sometimes idiopathic, it is often caused by injury to the recurrent laryngeal nerve during cardiac surgery. A detailed history and physical examination can identify risk factors, which affect the rate of resolution and overall prognosis. Fiberoptic laryngoscopy can be used to confirm the diagnosis and evaluate laryngeal anatomy. Many treatment options exist to improve function and quality of life, including vocal fold injection and laryngeal innervation. [Pediatr Ann. 2021;50(7):e286-e291.].

Dysphagia Severity and Outcomes Following Iatrogenic High Vagal Nerve Injury.

To examine severity of dysphagia and outcomes following iatrogenic high vagal nerve injury. Retrospective chart review of all patients with iatrogenic high vagal nerve injury that were seen at a tertiary referral center from 2012 to 2020. Of 1304 patients who met criteria for initial screening, 18 met all inclusion criteria. All 18 required intervention to address postoperative dysphagia. Eleven required enteral feeding tubes with 7 eventually able to advance to exclusively per oral diets. Fourteen underwent vocal fold injection and 6 underwent laryngeal framework surgery. Sixteen pursued swallowing therapy with speech language pathology. Patients lost a mean of 8.6 kg of weight in the 6 months following the injury. Swallowing function on the Functional Outcome Swallowing Scale (FOSS) and Functional Oral Intake Scale (FOIS) was 4.4 and 2.4 respectively immediately following the injury and improved to 1.9 and 5.3 at the last follow-up. No patients had complete return of normal swallowing function at last follow up. Iatrogenic high vagal injury causes significant lasting dysphagia which improves with intervention but does not completely resolve. Interventions such as vocal fold injection, medialization laryngoplasty, cricopharyngeal myotomy, or swallowing therapy may be required to reestablish safe swallowing in these patients.

Vocal fold injection material does not preclude interpretation of laryngeal electromyography.

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. Patients with acute and subacute unilateral VFP (onset ≤6mo) who underwent temporary VFI within 3mo 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. 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. 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.

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. 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). 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. 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.

Inflammatory complications of vocal fold injection with hyaluronic acid: a multiinstitutional study

Background/aimThis study aimed to assess the inflammatory adverse reactions of vocal fold injection laryngoplasty with hyaluronic acid.Materials and methods This study was a retrospective chart review of patients who underwent vocal fold injection augmentation with HA injection from January 2005 to September 2016 in nine different institutions. Demographic data, indication for injection, injection techniques, types of injection material, settings of procedure, and complications were reviewed. The types of complication, onset time, and management of complications were also noted.ResultsIn all, 467 patients were identified. The majority of patients had been injected under general anesthesia (n = 382, 84.7%). For injection material, two different types of hyaluronic acid were used: hyaluronic acid alone or hyaluronic acid with dextranomer. Complications occurred in nine patients (1.9%). The majority of complications were inflammatory reactions (n = 7, 1.47%). Main symptoms were dysphonia and/or dyspnea with an onset of 0 h to 3 weeks after the hyaluronic acid injection. Three patients were hospitalized, one of which was also intubated and observed in the intensive care unit for 24 h. Systemic steroids and antibiotics were the main medical treatment in the majority of cases. There was no statistical difference in complication rates between patients who received hyaluronic acid and those who received hyaluronic acid with dextranomer (P = 0.220). ConclusionHyaluronic acid can be considered as a safe substance for the injection of vocal folds with a low risk of inflammatory reaction.

Outcomes versus complications in patients undergoing different modalities of injection laryngoplasty

BackgroundGlottal insufficiency results in glottal gap between the two vocal folds, which in turn might cause dysphonia, dysphagia, and breathing problems. Vocal fold injection is considered a safe, reliable, and highly effective method of treatment.The purpose of the present study was to assess voice outcomes and complication rates in patients with glottal insufficiency undergoing injection laryngoplasty (IL) under local versus general anesthesia before, 1 week then 1 month after IL.ResultsExamined patients were 13 males and 12 females, suffering from dysphonia due to glottal insufficiency with mean age 43.68 ± SD 14.55. Unilateral vocal fold paralysis (UVFP) was diagnosed in seventeen cases, vocal fold scarring in six cases, presbylarynx in one case, and sulcus vocalis in one case. IL was performed in 18 cases under local anesthesia, and 7 under general anesthesia. Hyaluronic acid was injection material in 23 cases and calcium hydroxylapatite in two cases. IL by either local or general anesthesia has improved the patients’ auditory perceptual analysis of voice quality as assessed by “GRBAS” scale and Voice Handicap Index (VHI). There were four (16% of all injections) minor and self-limited complications (12% under local and 4% under general anesthesia).ConclusionInjection laryngoplasty performed under local and general anesthesia offers similar voice outcomes, but with slightly higher self-limited complications in IL under local anesthesia.

Platelet-Rich Plasma for Vocal Fold Scar: A Preliminary Report of Concept

Vocal fold atrophy and scar can lead to loss of normal superficial lamina propria, negatively affecting the vibratory function of the vocal fold. These changes can lead to dysphonia, vocal fatigue, decreased volume, and altered pitch. Treatment options for these conditions are limited. Platelet-rich plasma (PRP) consists of platelets, growth factors, and cytokines derived from the patient's own blood and is believed to activate tissue regeneration. The purpose of this study was to review the technical aspects of collecting PRP and injecting it into the vocal fold injection - based on our initial experience with this procedure. A patient with vocal fold scar was identified and enrolled in an ongoing prospective clinical trial study of a series of 4 monthly subepithelial vocal fold PRP injections, which was temporarily halted due to the COVID-19 pandemic. Patient underwent a single injection of autologous PRP into the left vocal fold. There were no adverse events during the study period. Subjective improvement in voice was noted at 1 month after injection with subsequent return to baseline over the next 4 months. Videostroboscopy performed on postinjection day 1 and day 7 and demonstrated no concerning exam changes. Compared to the preinjection baseline, the patient-reported voice-handicap index-10 (VHI-10) and voice catastrophization index were similar at 4 months following injection (20 to 20 and 4 to 3, respectively). Independent perceptual analysis of voice showed improvement at 4 months postinjection, compared to baseline consensus auditory-perceptual evaluation of voice 60 to 44. This preliminary report was part of a prospective trial investigating the use of PRP to treat vocal fold atrophy and scar. This work highlights the technical considerations for injecting PRP into the vocal fold. Planned prospective enrollment in this study will help to validate the safety and efficacy of PRP injections.

Anesthesia for Office Based Vocal Fold Injection

Vocal fold injections are usually performed with a patient wake in an office under local anesthesia. For comfortable and safe office-based procedures, thorough anesthesia and premedication should be provided to the following three regions; nasal cavity, oropharynx, and larynx. Topical lidocaine is most widely used anesthetics on office based procedure. Lidocaine has a low to intermediate potency, 45 minutes to 60 minutes’ duration of action, and onset of sufficient anesthesia within 90 seconds of topical administration. Tetracaine, prilocaine, ropivacaine, and bupivacaine also have been used in the office-based procedures. Nasal decongestant, oxymetazoline, is also used for widening nasal cavity by constriction of nasal mucosa. The amount of topical and local anesthetics used in vocal fold injection rarely exceeds toxic doses. The physician should know proper anesthesia techniques and must be familiar with the safe dose and complication of all anesthetics used. Key words: Vocal cords ㆍ Anesthesia ㆍ Laryngoplasty ㆍ Injection ㆍ Lidocaine ㆍ Oxymetazoline 핵심용어: 성대 ㆍ 마취 ㆍ í›„ë‘ì„±í˜•ìˆ ã† ì£¼ìž ã† 리도카인 ㆍ 옥시메타졸린

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

ObjectivesThe 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.MethodsThe 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.ResultsRL-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.ConclusionRL-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.