Laryngeal steroid injection for vocal fold scar

Drug delivery systems for wound healing treatment of upper airway injury

INTRODUCTION

Endotracheal intubation is a common procedure to maintain an open airway with risks for traumatic injury. Pathological changes resulting from intubation can cause upper airway complications, including vocal fold scarring, laryngotracheal stenosis, and granulomas and present with symptoms such as dysphonia, dysphagia, and dyspnea. Current intubation-related laryngotracheal injury treatment approaches lack standardized guidelines, relying on individual clinician experience, and surgical and medical interventions have limitations and carry risks.

AREAS COVERED

The clinical and preclinical therapeutics for wound healing in the upper airway are described. This review discusses the current developments on local drug delivery systems in the upper airway utilizing particle-based delivery systems, including nanoparticles and microparticles, and bulk-based delivery systems, encompassing hydrogels and polymer-based approaches.

EXPERT OPINION

Complex laryngotracheal diseases pose challenges for effective treatment, struggling due to the intricate anatomy, limited access, and recurrence. Symptomatic management often requires invasive surgical procedures or medications that are unable to achieve lasting effects. Recent advances in nanotechnology and biocompatible materials provide potential solutions, enabling precise drug delivery, personalization, and extended treatment efficacy. Combining these technologies could lead to groundbreaking treatments for upper airways diseases, significantly improving patients' quality of life. Research and innovation in this field are crucial for further advancements.

Endotracheal tubes with dexamethasone eluting electrospun coating improve tissue mechanical function after upper airway injury

Corticosteroid-eluting endotracheal tubes (ETTs) were developed and employed in a swine laryngotracheal injury model to maintain airway patency and provide localized drug delivery to inhibit fibrotic scarring. Polycaprolactone (PCL) fibers with or without dexamethasone were electrospun onto the ETT surface PCL-only coated ETTs and placed in native airways of 18 Yorkshire swine. Regular and dexamethasone-PCL coated ETTs were placed in airways of another 18 swine injured by inner laryngeal mucosal abrasion. All groups were evaluated after 3, 7 and 14 days (n = 3/treatment/time). Larynges were bisected and localized stiffness determined by normal indentation, then sequentially matched with histological assessment. In the native airway, tissue stiffness with PCL-only ETT placement increased significantly from 3 to 7 days (p = 0.0016) and 3 to 14 days (p < 0.0001) while dexamethasone-PCL ETT placement resulted in stiffness decreasing from 7 to 14 days (p = 0.031). In the injured airway, localized stiffness at 14 days was significantly greater after regular ETT placement (23.1 ± 0.725 N/m) versus dexamethasone-PCL ETTs (17.10 ± 0.930 N/m, p < 0.0001). Dexamethasone-loaded ETTs were found to reduce laryngotracheal tissue stiffening after simulated intubation injury compared to regular ETTs, supported by a trend of reduced collagen in the basement membrane in injured swine over time. Findings suggest localized corticosteroid delivery allows for tissue stiffness control and potential use as an approach for prevention and treatment of scarring caused by intubation injury.

Acute Effects of Systemic Glucocorticoids on the Vocal Folds in a Pre-Clinical Model

OBJECTIVES/HYPOTHESIS

Systemic glucocorticoids (GC)s are employed to treat various voice disorders. However, GCs have varying pharmacodynamic properties with adverse effects ranging from changes in epithelial integrity, skeletal muscle catabolism, and altered body weight. We sought to characterize the acute temporal effects of systemic dexamethasone and methylprednisolone on vocal fold (VF) epithelial glucocorticoid receptor (GR) nuclear translocation, epithelial tight junction (ZO-1) expression, thyroarytenoid (TA) muscle fiber morphology, and body weight using an established pre-clinical model. We hypothesized dexamethasone and methylprednisolone will elicit changes in VF epithelial GR nuclear translocation, epithelial ZO-1 expression, TA muscle morphology, and body weight compared to placebo-treated controls.

METHODS

Forty-five New Zealand white rabbits received intramuscular injections of methylprednisolone (4.5 mg; n = 15), dexamethasone (450 µg; n = 15), or volume matched saline (n = 15) into the iliocostalis/longissimus muscle for 6 consecutive days. Vocal folds from 5 rabbits from each treatment group were harvested at 1-, 3-, or 7 days following the final injection and subjected to immunohistochemistry for ZO-1 and GR as well as TA muscle fiber cross-sectional area (CSA) measures.

RESULTS

Dexamethasone increased epithelial GR nuclear translocation and ZO-1 expression 1-day following injections compared to methylprednisolone (P = .024; P = .012). Dexamethasone and methylprednisolone increased TA CSA 1-day following injections (P = .011). Methylprednisolone decreased body weight 7 days following injections compared to controls (P = .004).

CONCLUSIONS

Systemic dexamethasone may more efficiently activate GR in the VF epithelium with a lower risk of body weight loss, suggesting a role for more refined approaches to GC selection for laryngeal pathology.

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.

Functional Analysis of Injectable Substance Treatment on Surgically Injured Rabbit Vocal Folds

OBJECTIVES

The objective of this study was to evaluate the efficacy of immediate injection treatments of dexamethasone, hyaluronic acid (HA)/gelatin (Ge) hydrogel and glycol-chitosan solution on the phonatory function of rabbit larynges at 42 days after surgical injury of the vocal folds, piloting a novel ex vivo phonatory functional analysis protocol.

METHODS

A modified microflap procedure was performed on the left vocal fold of 12 rabbits to induce an acute injury. Animals were randomized into one of four treatment groups with 0.1 mL injections of dexamethasone, HA/Ge hydrogel, glycol-chitosan or saline as control. The left mid vocal fold lamina propria was injected immediately following injury. The right vocal fold served as an uninjured control. Larynges were harvested at Day 42 after injection, then were subjected to airflow-bench evaluation. Acoustic, aerodynamic and laryngeal high-speed videoendoscopy (HSV) analyses were performed. HSV segments of the vibrating vocal folds were rated by three expert laryngologists. Six parameters related to vocal fold vibratory characteristics were evaluated on a Likert scale.

RESULTS

The fundamental frequency, one possible surrogate of vocal fold stiffness and scarring, was lower in the dexamethasone and HA/Ge hydrogel treatment groups compared to that of the saline control (411.52±11.63 Hz). The lowest fundamental frequency value was observed in the dexamethasone group (348.79±14.99 Hz). Expert visual ratings of the HSV segments indicated an overall positive outcome in the dexamethasone treatment group, though the impacts were below statistical significance.

CONCLUSION

Dexamethasone injections might be used as an adjunctive option for iatrogenic vocal fold scarring. An increased sample size, histological correlate, and experimental method improvements will be needed to confirm this finding. Results suggested a promising use of HSV and acoustic analysis techniques to identify and monitor post-surgical vocal fold repair and scarring, providing a useful tool for future studies of vocal fold scar treatments.

Platelet-rich plasma in treatment of scar, atrophy, and sulcus: Short- and long-term results

Objective

Platelet-rich plasma (PRP) is rich in growth factors and is easily obtained from blood samples. Long-term data after PRP injection into the larynx should be improved. This study reports the short-term (3 months) and long-term (12 months) voice results after PRP injection.

Materials and Methods

Sixty-three patients with scars (n = 34), sulcus vocalis (n = 17), recalcitrant nodules (n = 5), atrophy (n = 4), or a combination of these (n = 3) were included (158 injections; median follow-up = 12.3 months). Stroboscopy, voice handicap index (VHI-10), and cepstral spectral index of dysphonia (CSID) before and after treatment (3 months) and at 12 months were tabulated.

Results

VHI-10 changed from 19.5 to 14 at 3 months and 21 to 15 in the long term. The CSID scores improved from 31 to 21 in the short term and 31 to 26 in the long term (p < 0.001, paired t-test). Patients reported improved vocal effort and stamina with slight VHI or CSID score changes. Stroboscopy revealed improved closure and mucosal waves. Patients with severe dysphonia were less likely to improve compared to those with mild to moderate dysphonia. Some patients showed short-term improvements and then deteriorated back to baseline CSID over time (p < .05, paired t-test).

Conclusion

Both short- and long-term improvements in voice following PRP injection have been reported. Patients with mild-to-moderate dysphonia had better outcomes. PRP injection is an alternative treatment for patients with mild-to-moderate dysphonia due to vocal fold scarring, sulcus, and atrophy.

Level of evidence

II Prospective case series treatment.

Acute In Vitro and In Vivo Effects of Dexamethasone in the Vocal Folds: a Pilot Study

OBJECTIVES/HYPOTHESIS

Glucocorticoids (GC)s are commonly employed to treat vocal fold (VF) pathologies. However, VF atrophy has been associated with intracordal GC injections. Dexamethasone-induced skeletal muscle atrophy is well-documented in other tissues and believed to be mediated by increased muscle proteolysis via upregulation of Muscle Ring Finger (MuRF)-1 and Atrogin-1. Mechanisms of dexamethasone-mediated VF atrophy have not been described. This pilot study employed in vitro and in vivo models to investigate the effects of dexamethasone on VF epithelium, thyroarytenoid (TA) muscle, and TA-derived myoblasts. We hypothesized that dexamethasone will increase atrophy-associated gene expression in TA muscle and myoblasts and decrease TA muscle fiber size and epithelial thickness.

STUDY DESIGN

In vitro, pre-clinical.

METHODS

TA myoblasts were isolated from a female Sprague-Dawley rat and treated with 1 μM dexamethasone for 24-h. In vivo, 15 New Zealand white rabbits were randomly assigned to three treatment groups: (1) bilateral intracordal injection of 40 μL dexamethasone (10 mg/ml; n = 5), (2) volume-matched saline (n = 5), and (3) untreated controls (n = 5). Larynges were harvested 7-days post-injection. Across in vivo and in vitro experimentation, MuRF-1 and Atrogin-1 mRNA expression were measured via RT-qPCR. TA muscle fiber cross-sectional area (CSA) and epithelial thickness were also quantified in vivo.

RESULTS

Dexamethasone increased MuRF-1 gene expression in TA myoblasts. Dexamethasone injection, however, did not alter atrophy-associated gene expression, TA CSA, or epithelial thickness in vivo.

CONCLUSION

Dexamethasone increased atrogene expression in TA myoblasts, providing foundational insight into GC induced atrophic gene transcription. Repeated dexamethasone injections may be required to elicit atrophy in vivo.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2264-2270, 2023.

Duration of Clinical Response After In-Office Steroid Injection for Vocal Fold Scar

OBJECTIVE

To assess the duration of clinical response after in-office vocal fold steroid injection (VFSI) for vocal fold (VF) scar.

METHODS

Demographic and clinical data for in-office VFSI occurring from 2017 to 2020 were collected. Two Speech-Language Pathologists (SLPs) used perceptual evaluation of voice and functional scales to evaluate blinded voice and laryngovideostroboscopy (LVS) samples collected pre- and post-injection across multiple timepoints.

RESULTS

Blinded SLP ratings were used for 30 individual VFs undergoing initial injection in 18 patients. Persistent improvement in voice past 6 months was seen in 57% of patients after VFSI. Multiple measures of voice and amplitude, percent vibrating tissue, and closed phase predominance significantly improved at various follow-up timepoints on average.

CONCLUSION

Accounting for patient heterogeneity and disease progression, in-office VFSI for VF scar is associated with sustained improvement in a subset of patients. Approximately half of patients can expect to experience a lasting improvement in voice. Future studies of larger scale are required to identify patient factors associated with long-term benefit.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2333-2339, 2023.

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

INTRODUCTION

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.

CASE

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.

CONCLUSIONS

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.

Intracordal injection therapy for vocal fold scarring: Steroid versus basic fibroblast growth factor

Objectives

Vocal fold scarring is caused by replacement of vocal fold mucosa with fibrous tissue due to repeated inflammation or trauma. It can lead to severe dysphonia. It is currently treated conservatively and with phonosurgery and intracordal injections. Intracordal injection of steroid or basic fibroblast growth factor (bFGF) has been recently found to be useful for treating vocal fold scarring that does not respond to voice therapy.

Methods

This retrospective study involved the administration of steroid injection and bFGF injection bilaterally under local anesthesia in 16 patients each. Laboratory measurements of voice parameters were performed before and 3–6 months after injection.

Results

In the steroid injection group, the Voice Handicap Index (VHI) score significantly improved from 57.1 to 40.5, total Grade, Roughness, Breathiness, Asthenia, Strain (tGRBAS) score significantly improved from 4.2 to 2.6, and mean speech fundamental frequency (SFF) increased from 192.5 to 211.4 dB, but there was no improvement in maximum phonation time (MPT) and mean airflow rate (MFR). In the bFGF injection group, significant improvements in the VHI score (from 53.3 to 35.7), MPT (from 16.9 to 21.8 s) and MFR (from 314.6 to 210.5 ml/s) were seen; however, the tGRBAS score did not improve. In addition, the SFF significantly decreased from 178.1 to 160.5 Hz.

Conclusion

These results suggest that both steroid and bFGF injections are effective for treating vocal fold scarring, with steroids improving voice quality and bFGF improving glottic closure, thereby contributing to improvements in VHI scores.

Level of Evidence

4.

The role of platelet-rich plasma in microlaryngeal surgery: a randomised, controlled trial

Objective

Platelet-rich plasma has gained interest over the two last decades, mainly because of its role in regenerative medicine. This work aimed to assess the role of intra-operative local application of platelet-rich plasma gel in the improvement of quality of voice after microlaryngeal surgery.

Method

This was a prospective comparative study that included 40 patients undergoing microlaryngeal surgery for benign vocal fold lesions. There were two groups divided equally into study group A and control group B. The assessment of voice was performed by videostroboscopy and acoustic analysis pre-operatively and at two weeks and one and three months post-operatively.

Results

The data demonstrated that all the stroboscopic and acoustic parameters showed significant improvement in both groups. Group A showed significant improvement regarding acoustic parameters at the third post-operative follow up when compared with group B.

Conclusion

Platelet-rich plasma has a beneficial effect on voice quality following microlaryngeal surgery based in particular on acoustic parameters.

Human amniotic epithelial cell transplantation improves scar remodeling in a rabbit model of acute vocal fold injury: a pilot study

Objective

To gain insight into the molecular mechanisms underlying the early stages of vocal fold extracellular matrix (ECM) remodeling after a mid-membranous injury resulting from the use of human amniotic epithelial cells (hAEC), as a novel regenerative medicine cell-based therapy.

Methods

Vocal folds of six female, New Zealand White rabbits were bilaterally injured. Three rabbits had immediate bilateral direct injection of 1 × 10⁶ hAEC in 100 µl of saline solution (hAEC) and three with 100 µl of saline solution (controls, CTR). Rabbits were euthanized 6 weeks after injury. Proteomic analyses (in-gel trypsin protein digestion, LC–MS/MS, protein identification using Proteome Discoverer and the Uniprot Oryctolagus cuniculus (Rabbit) proteome) and histological analyses were performed.

Results

hAEC treatment significantly increased the expression of ECM proteins, elastin microfibril interface-located protein 1 (EMILIN-1) and myocilin that are primarily involved in elastogenesis of blood vessels and granulation tissue. A reactome pathway analysis showed increased activity of the anchoring fibril formation by collagen I and laminin, providing mechanical stability and activation of cell signaling pathways regulating cell function. hAEC increased the abundance of keratin 1 indicating accelerated induction of the differentiation programming of the basal epithelial cells and, thereby, improved barrier function. Lastly, upregulation of Rab GDP dissociation inhibitor indicates that hAEC activate the vesicle endocytic and exocytic pathways, supporting the exosome-mediated activation of cell–matrix and cell-to-cell interactions.

Conclusions

This pilot study suggests that injection of hAEC into an injured rabbit vocal fold favorably alters ECM composition creating a microenvironment that accelerates differentiation of regenerated epithelium and promotes stabilization of new blood vessels indicative of accelerated and improved repair.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02701-w.

Intra-Lesional Injection of Triamcinolone to Palatoplasty Scar to Aid Reversal of Transverse Maxillary Relapse after Orthognathic Surgery

ABSTRACT

A 32-year-old female with a repaired right unilateral cleft lip and palate underwent several surgical and orthodontic procedures during the rehabilitation process of her condition. Nine years after this extensive treatment she underwent transverse relapse of her maxilla and requested a consultation for its correction as she felt her speech and chewing were negatively affected. She presented with a transverse maxillary arch collapse on the cleft side with significant palatal scarring secondary to multiple palate procedures. A course of maxillary expansion and dental alignment with fixed orthodontic appliances was carried out. In addition, she had 2 triamcinolone injections 7 months apart while undergoing orthodontic treatment and one 10 months after completion to soften the scarred palatal tissues. The maxillary arch was successfully expanded and aligned. She was retained with a removable chrome cobalt palatal frame to be used full-time and assure stability of the correction. She has been followed for 4 years with no clinical evidence of relapse. Triamcinolone injection into significant palatal scarring in cleft palate patients with a decreased transverse maxillary dimension can be considered an adjunct procedure in conjunction with orthodontic treatment.

Short-Term Voice Improvement after Repeated Office-Based Platelet-Rich Plasma PRP Injection in Patients with Vocal Fold Scar, Sulcus, and Atrophy

INTRODUCTION

Improving the voice of patients with vocal atrophy, scar, and sulcus vocalis remains challenging. Platelet-rich plasma (PRP) is an autologous biological suitable for regenerative medicine. Office-based injections of PRP may serve as a source of improved wound healing.

MATERIALS AND METHODS

Thirty two office based injections of PRP were performed in 14 patients with scar, sulcus, and vocal atrophy (12 scars, 1 sulcus, and 1 atrophy). PRP was prepared using 20 cc blood draw and double centrifugation method. Injection laryngoplasty was performed using trans cervical or indirect trans oral technique (10 trans cervical, 22 trans-oral). Volume of PRP use was 0.5-0.7 cc per side. Injections varied from 1 to 3 injections at monthly intervals. Videostroboscopy, Voice Handicap Index (VHI-10), and an objective analysis of the voice using Cepstral Peak Prominence (Cepstral Spectral Index of Dysphonia) were recorded. An expert rater speech pathologist rated the audio and stroboscopy results.

RESULTS

Median follow-up was 15 months. No patients were made worse. The mean VHI-10 before the injection was 23. VHI-10 after the injection was 12.5 (P < 0.01). The mean Cepstral Spectral Index of Dysphonia score for CAPE-V sentence was 42.5 before the injection and 23.5 (P < 0.01) after the injection. The expert rater thought the post treatment was better (9/14 acoustic, 10/14 stroboscopy). Eleven of the 14 patients thought the intervention was worthwhile to repeat. The other 3 patients thought the improvement was transient.

CONCLUSION

Office PRP injection into the vocal fold of patients with scar, sulcus, and atrophy may result in short term voice improvements. It is a biological worth considering.

First-line treatment of exudative vocal fold-lesions by in-office local corticosteroid injection: A literature review

OBJECTIVES

There are emerging reports of the effectiveness of in-office awake vocal-fold corticosteroid injection in the treatment of exudative vocal-fold lesions. The aim of this study was to review this therapy and specify indications, practical modalities and outcomes.

STUDY DESIGN

Systematic review of the literature without meta-analysis.

METHODS

A systematic review by PubMed search for the period January 2000 to December 2018 was carried out.

RESULTS

Nine articles were included, for a total of 502 lesions: nodules (46.4%), polyps (31.7%), and Reinke's edema (21.9%). Submucosal injection of low-dose triamcinolone acetonide (0.1 to 0.3mL) was transoral, transcutaneous or transnasal via flexible endoscope with operating channel. Lesion volume was significantly reduced in more than 90% of cases, with significant vocal improvement in all studies. Relapse rates ranged between 4% and 31%, with time to relapse of 1 to 40 months.

CONCLUSIONS

First-line treatment of exudative glottic lesions by submucosal corticosteroid injection provides at least transient significant reduction in lesion volume and vocal improvement. It is consensually reserved to moderate-sized mainly exudative lesions without fibrosis. In-office injection provides an immediate therapeutic response in case of vocal impairment, enabling surgery under general anesthesia to be postponed.

Autologous fibroblasts for vocal scars and age-related atrophy: A randomized clinical trial

OBJECTIVES/HYPOTHESIS

To assess the safety and efficacy of autologous cultured fibroblasts (ACFs) to treat dysphonia related to vocal fold scar and age-related vocal atrophy (ARVA).

STUDY DESIGN

Randomized, double-blinded, placebo-controlled, multi-institutional, phase II trial.

METHODS

ACFs were expanded from punch biopsies of the postauricular skin in each subject; randomization was 2:1 (treatment vs. placebo). Three injections of 1-2 × 10⁷ cells or placebo saline was performed at 4-week intervals for each vocal fold. Follow-up was performed at 4, 8, and 12 months. The primary outcome was improved mucosal waves. Secondary outcomes included Voice Handicap Index (VHI)-30, patient reported voice quality outcomes, and perceptual analysis of voice.

RESULTS

Fifteen subjects received ACF and six received saline injections. At 4, 8, and 12 months after ACF treatments, a significant improvement in mucosal wave grade relative to baseline was observed in both vocal scar and ARVA groups. Relative to control group, mucosal waves were significantly improved in the ARVA group at 4 and 8 months. Perceptual analysis significantly improved in the vocal scar group 12 months after ACF treatments compared to controls. Vocal scar group reported significantly improved vocal quality from baseline. VHI and expert rater voice grade improved in both groups, but did not achieve significance. No adverse events related to fibroblast injections were observed.

CONCLUSIONS

In this cohort, injection of ACFs into the vocal fold lamina propria (LP) was safe and significantly improved mucosal waves in patients with vocal scar and ARVA. ACF may hold promise to reconstruct the LP.

LEVEL OF EVIDENCE

1 Laryngoscope, 130:2650-2658, 2020.

Pathophysiology of Fibrosis in the Vocal Fold: Current Research, Future Treatment Strategies, and Obstacles to Restoring Vocal Fold Pliability

Communication by voice depends on symmetrical vibrations within the vocal folds (VFs) and is indispensable for various occupations. VF scarring is one of the main reasons for permanent dysphonia and results from injury to the unique layered structure of the VFs. The increased collagen and decreased hyaluronic acid within VF scars lead to a loss of pliability of the VFs and significantly decreases their capacity to vibrate. As there is currently no definitive treatment for VF scarring, regenerative medicine and tissue engineering have become increasingly important research areas within otolaryngology. Several recent reviews have described the problem of VF scarring and various possible solutions, including tissue engineered cells and tissues, biomaterial implants, stem cells, growth factors, anti-inflammatory cytokines antifibrotic agents. Despite considerable research progress, these technical advances have not been established as routine clinical procedures. This review focuses on emerging techniques for restoring VF pliability using various approaches. We discuss our studies on interactions among adipose-derived stem/stromal cells, antifibrotic agents, and VF fibroblasts using an in vitro model. We also identify some obstacles to advances in research.

Retention of Human-Induced Pluripotent Stem Cells (hiPS) With Injectable HA Hydrogels for Vocal Fold Engineering

Objective:

One prospective treatment option for vocal fold scarring is regeneration with an engineered scaffold containing induced pluripotent stem cells (iPS). In the present study, we investigated the feasibility of utilizing an injectable hyaluronic acid (HA) scaffold encapsulated with human-iPS cell (hiPS) for regeneration of vocal folds.

Methods:

Thirty athymic nude rats underwent unilateral vocal fold injury. Contralateral vocal folds served as uninjured controls. Hyaluronic acid hydrogel scaffold, HA hydrogel scaffold containing hiPS, and HA hydrogel scaffold containing hiPS with epidermal growth factor (EGF) were injected in both vocal folds immediately after surgery. One and 2 weeks after injection, larynges were excised for histology, immunohistochemistry, and fluorescence in situ hybridization (FISH).

Results:

Presence of HA hydrogel was confirmed in vocal folds 1 and 2 weeks post injection. The FISH analysis confirmed the presence and viability of hiPS in the injected vocal folds. Histological results demonstrated that vocal folds injected with HA hydrogel scaffold containing EGF demonstrated less fibrosis than those with HA hydrogel only.

Conclusions:

Human-iPS survived in injured rat vocal folds. The HA hydrogel with hiPS and EGF ameliorated the fibrotic response. Additional work is necessary to optimize hiPS differentiation and further confirm the safety of hiPS for clinical applications.

The use of injectable calcium hydroxylapatite in the surgically pretreated larynx with glottal insufficiency

OBJECTIVES/HYPOTHESIS

To evaluate the efficacy of vocal fold (VF) augmentation with calcium hydroxylapatite (CaHA) microspheres in the surgically pretreated larynx with glottal insufficiency.

STUDY DESIGN

Prospective clinical pilot study.

METHODS

After several prior reconstructive attempts (following tumor resection, VF paralysis, in sulcus vocalis, and VF scarring), CaHA was injected under general anaesthesia using a transoral microlaryngoscopic approach in 10 patients with residual glottal insufficiency ≤1.5 mm. The postinterventional result was assessed after 1 day, and 1 and 3 months. Evaluation of augmentation comprised intraoperative video/photo documentation, pre-/postoperative videolaryngostroboscopy, as well as established subjective and objective voice function diagnostics (Grade, Roughness, Breathiness [GRB] Scale; Voice Handicap Index; voice range profile; and acoustic-aerodynamic analysis).

RESULTS

In the pretreated VF with no or minimal lamina propria remaining, the exact placement of CaHA was not possible due to unpredictable propagation into the scarred tissue. The results showed an insufficient postoperative augmentation. Accordingly, the voice function did not improve. However, a significant increase of the vocal range from 6.2 ± 3.2 to 8.7 ± 3.9 semitones was observed in the speaking voice profile (P =.02). All other acoustic and aerodynamic parameters remained on the whole unchanged; the slight differences between pre- and postoperative findings were not significant.

CONCLUSIONS

The application of CaHA in the surgically pretreated scarred larynx is not reliable to achieve a sufficient glottal closure and a satisfactory improvement of voice. Though CaHA is a welcome addition to our armamentarium against glottal insufficiency, the suitability for augmentation of scar tissue in the larynx must be considered carefully in each individual case.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:1125-1130, 2017.

Voice Outcomes following a Single Office-Based Steroid Injection for Vocal Fold Scar

OBJECTIVE

Persistent dysphonia from vocal fold scar remains a clinical challenge, with current therapies providing inconsistent outcomes. We evaluated voice outcomes after a single office-based steroid injection.

STUDY DESIGN

Case series with chart review.

SETTING

Academic medical center.

SUBJECTS AND METHODS

This study was based on pre- and postoperative analysis of patient-reported, perceptual, acoustic, aerodynamic, and videostroboscopic parameters. The sample comprised 25 patients undergoing office-based dexamethasone injection into the superficial lamina propria for mild/moderate vocal fold scar. Average follow-up was 13.7 ± 4.4 weeks; patients completed 3.5 ± 2.3 sessions of voice therapy between assessments. Complete data sets were not available for each parameter; sample size is noted with results.

RESULTS

Voice handicap index (n = 24; P < .001) and glottal function index (n = 22; P < .001) decreased after injection. Total GRBAS score (grade, roughness, breathiness, asthenia, strain) decreased (n = 25; P < .001). Fundamental frequency range increased (n = 24; P = .024). Phonation threshold pressure decreased (n = 14; P = .017). Videostroboscopic parameters of vocal fold edge (P = .004), glottic closure (P = .003), and right mucosal wave (P = .016) improved after injection.

CONCLUSIONS

Office-based steroid injection combined with voice therapy for mild/moderate vocal fold scar is associated with improved patient-reported and functional voice measures. These findings provide preliminary support for this approach. Importantly, the procedure is low risk and can be performed in the office, thus offering a simple treatment alternative to patients with a disorder that has traditionally been difficult to manage. Prospective studies evaluating the effects of multiple injections are warranted.

Differential responses to steroid hormones in fibroblasts from the vocal fold, trachea, and esophagus

There is accumulating evidence that fibroblasts are target cells for steroids such as sex hormones and corticoids. The characteristics of fibroblasts vary among tissues and organs. Our aim in this study is to examine differences in responses to steroid hormones among fibroblasts from different cervicothoracic regions. We compared the actions of steroid hormones on cultured fibroblasts from the vocal folds, which are considered to be the primary target of steroid hormones, and the trachea and esophagus in adult male rats. Expression of steroid hormone receptors (androgen receptor, estrogen receptor α, and glucocorticoid receptor) was identified by immunofluorescence histochemistry. Androgen receptor was much more frequently expressed in fibroblasts from the vocal fold than in those from the trachea and esophagus. Cell proliferation analysis showed that administration of testosterone, estradiol, or corticosterone suppressed growth of all 3 types of fibroblasts. However, mRNA expression for extracellular matrix-associated genes, including procollagen I and III and elastin, and hyaluronic acid synthase I was elevated only by addition of testosterone to fibroblasts from the vocal fold. These results indicate that each steroid hormone exerts region-specific effects on cervicothoracic fibroblasts with different properties through binding to specific receptors.

Diagnostic and therapeutic pitfalls in benign vocal fold diseases

More than half of patients presenting with hoarseness show benign vocal fold changes. The clinician should be familiar with the anatomy, physiology and functional aspects of voice disorders and also the modern diagnostic and therapeutic possibilities in order to ensure an optimal and patient specific management. This review article focuses on the diagnostic and therapeutic limitations and difficulties of treatment of benign vocal fold tumors, the management and prevention of scarred vocal folds and the issue of unilateral vocal fold paresis.

Picosecond infrared laser (PIRL): an ideal phonomicrosurgical laser?

A comparison of tissue cutting effects in excised cadaver human vocal folds after incisions with three different instruments [scalpel, CO2 laser and the picosecond infrared laser-(PIRL)] was performed. In total, 15 larynges were taken from human cadavers shortly after death. After deep freezing and thawing for the experiment, the vocal folds suspended in the hemilarynx were incised. Histology and environmental scanning electron microscopy (ESEM) analyses were performed. Damage zones after cold instrument cuts ranged from 51 to 135 μm, as compared to 9-28 μm after cutting with the PIRL. It was shown that PIRL incision had smaller zones of tissue coagulation and tissue destruction, when compared with scalpel and CO2 laser cuts. The PIRL technology provides an (almost) atraumatic laser, which offers a quantum jump towards realistic 'micro'-phonosurgery on a factual cellular dimension, almost entirely avoiding coagulation, carbonization, or other ways of major tissue destruction in the vicinity of the intervention area. Although not available for clinical use yet, the new technique appears promising for future clinical applications, so that technical and methodological characteristics as well as tissue experiments seem worthwhile to be communicated at this stage of development.

Voice Outcomes from Subligamentous Cordectomy for Early Glottic Cancer

Objectives:

We evaluated the voice and vocal fold pliability outcomes of European Laryngological Society (ELS) deep type I (subepithelial) and type II (subligamentous) cordectomies for early glottic cancer.

Methods:

We reviewed the medical records of patients with glottic carcinoma at a tertiary care medical center between 2005 and 2011. Their procedures were stratified into ELS type I and ELS type II cordectomies. The data recorded included age, gender, tumor stage, recurrence, patient-assessed voice-related quality of life, perceptual voice evaluation, and stroboscopy.

Results:

Four patients were identified as having subepithelial cordectomy, and 13 as having subligamentous cordectomy. The average preoperative and postoperative voice-related quality of life scores were 65 and 74 for the ELS I cohort and 64 and 95 for the ELS II group. The preoperative and postoperative perceptual voice evaluation scores were 56 and 35 for the ELS I cohort and 45 and 21 for the ELS II cohort. The ELS I cohort had a moderately to severely reduced mucosal wave, with 75% of patients demonstrating glottic insufficiency, whereas the ELS II cohort had a mildly to moderately reduced mucosal wave, with 8% of patients demonstrating glottic insufficiency. The survival outcomes were the same.

Conclusions:

Patients who underwent subligamentous excision of early glottic cancer had significantly improved postoperative voice and stroboscopy scores. This finding suggests that if tumor resection reaches the vocal ligament, and minimal superficial lamina propria can be preserved, subligamentous cordectomy should be performed.

Radiation fibrosis of the vocal fold: from man to mouse

OBJECTIVES/HYPOTHESIS

To characterize fundamental late tissue effects in the human vocal fold following radiation therapy. To develop a murine model of radiation fibrosis in order to ultimately develop both treatment and prevention paradigms.

DESIGN

Translational study using archived human and fresh murine irradiated vocal fold tissue.

METHODS

1) Irradiated vocal fold tissue from patients undergoing laryngectomy for loss of function from radiation fibrosis was identified from pathology archives. Histomorphometry, immunohistochemistry, and whole-genome microarray, as well as real-time transcriptional analyses, were performed. 2) Focused radiation to the head and neck was delivered to mice in a survival fashion. One month following radiation, vocal fold tissue was analyzed with histomorphometry, immunohistochemistry, and real-time PCR transcriptional analysis for selected markers of fibrosis.

RESULTS

Human irradiated vocal folds demonstrated increased collagen transcription, with increased deposition and disorganization of collagen in both the thyroarytenoid muscle and the superficial lamina propria. Fibronectin were increased in the superficial lamina propria. Laminin decreased in the thyroarytenoid muscle. Whole genome microarray analysis demonstrated increased transcription of markers for fibrosis, oxidative stress, inflammation, glycosaminoglycan production, and apoptosis. Irradiated murine vocal folds demonstrated increases in collagen and fibronectin transcription and deposition in the lamina propria. Transforming growth factor (TGF)-β increased in the lamina propria.

CONCLUSION

Human irradiated vocal folds demonstrate molecular changes leading to fibrosis that underlie loss of vocal fold pliability occurring in patients following laryngeal irradiation. The irradiated murine tissue demonstrates similar findings, and this mouse model may have utility in creating prevention and treatment strategies for vocal fold radiation fibrosis.