Immunohistochemical characterization of benign laryngeal lesions

Revisiting the etiology and clinical characteristics of hemorrhagic polyps of the vocal fold

Objective

Benign phonotraumatic lesions of the vocal folds (BVFLs) are typically seen in younger female patients with high vocal loads. Hemorrhagic polyps (HPs) do not fit the classic paradigm of most BVFLs, as they tend to occur in an older population, have a male predominance, and report to result from a vocal accident. We present one of the largest cohorts of HPs, to reexamine their etiology and clinical features.

Methods

Retrospective cohort study, inclusive of all patients with HP managed by the senior authors between the years 2016 through 2023. Demographic data, management, phonotraumatic risk factors, pre- and post-treatment VHI-10 were reviewed. We examined patient videostroboscopy, categorized the size of the lesion, and identified any concurrent mucosal abnormality.

Results

One hundred and eleven patients had confirmed HP, 84 males (75.7%). Thirty-five patients were size category 1; pinpoint (28.9%), 57 were category 2; less than 1/3rd the vocal fold (45.5%), and 26 were category 3; greater than 1/3rd the vocal fold (21.5%). Ten patients (9%) had bilateral HPs. Thirty-five patients had an additional 40 mucosal lesions in addition to the HP(s). The onset of symptoms was gradual in 60% of patients. The mean pretreatment VHI-10 was 18.0 (SD 10.7), compared to 6.0 (SD 10.5) post-treatment, (p < .001). 57/111 patients reported high voice demand professions or recreational activities. The average self-reported talkative scale score was 7.6/10. Patients were managed with operative microdirect laryngoscopy and microflap excision (53.1%), in-office clinic potassium titanyl phosphate (KTP) laser (24.3%), voice therapy alone (7.2%), and KTP in the operating room (6.3%).

Conclusions

In our cohort, most patients were male, had high vocal demands, reported gradual symptom onset, and almost a third of patients had additional BVFLs.

Level of evidence

Level 3: Retrospective cohort study.

Mechanotransduction in the Vocal Fold Microenvironment: A Narrative Review

PURPOSE

The vocal fold tissues undergo nearly continuous and repeated cycles of injury and repair throughout the course of an individual's lifetime. It is well established that certain individuals are at greater risk of lesion development based on personality and behavioral classification. However, these characteristics alone do not wholly predict or explain lesion development or severity. In this review, we discuss current knowledge of mechanotransduction proteins and their potential relevance to tissue homeostasis in the vocal folds.

METHOD

A review of literature surrounding mechanotransduction and tissue homeostasis as it relates to the vocal folds was conducted. Review of the literature included searches of PubMed, Google Scholar, and other various online peer-reviewed sources. Search terms pertained to mechanosensation, mechanotransduction, mechanically activated channels, mechanical cellular regulation, and other associated concepts and terms. Additional literature was identified through the reference lists of identified papers. Findings of this literature review were then applied to known physiology and pathophysiology of the vocal folds in order to speculate on the contribution of mechanically mediated mechanisms within the vocal fold.

DISCUSSION AND CONCLUSION

Because the vocal folds are such mechanically active structures, withstanding nearly constant external forces, there is strong support for the idea that mechanically sensitive molecular pathways within the vocal fold tissue play a major role in tissue homeostasis in the presence of these considerable forces. As such, mechanotransduction within the vocal fold should be considered and targeted in future biological studies of vocal fold physiology.

A Retrospective Study of Glottic Cyst Histopathology and Its Clinical Presentation

To understand the frequency and clinical presentation of the four types of vocal-fold cyst described by the Koren classification. Glottic cysts operated in a 1-year period were grouped retrospectively into Koren A, B, C and D (KA, KB, KC, KD). The age and sex of the patient, cyst location, laterality, associated lesions, profession, daily water consumption, duration of symptoms prior to surgery and postoperative healing time were noted. Of 30 cysts, 14 KA, 10 KB, 4 KC and 2 KD were identified. Average age of symptoms in KA to KD was 45, 52, 40 and 37 years. KC and KD were found only in females unlike the male predominance of KA and KB. Striking zone was the location of 28/30 cysts with a focal pit in 1 KC and mucosal bridge in 1 KD. There was no significance to laterality or profession. Average daily water consumption was 1.8, 1.75, 2 and 2 L in KA to KD. Average duration of symptoms up-till surgery for KA to KD was 2.6 years, 1.4 years, 2.9 years and 1 month. Post-operative healing time for KA to KD was 6.6, 7.4, 11.7 and 10 weeks. KA was the commonest cyst excised followed by KB, KC and KD. The KD patients were earliest and youngest to present. All KC and KD cysts were found in females unlike the male predominance of KA and KB. As majority of the cysts were found on the striking zone, phonotrauma may be one of the etiologies for all four cysts.

The Effect of Oxidative Stress on the Human Voice

The vocal fold vibrates in high frequency to create voice sound. The vocal fold has a sophisticated histological "layered structure" that enables such vibration. As the vibration causes fricative damage to the mucosa, excessive voicing can cause inflammation or injury to the mucosa. Chronic inflammation or repeated injury to the vocal fold occasionally induces scar formation in the mucosa, which can result in severe dysphonia, which is difficult to treat. Oxidative stress has been proven to be an important factor in aggravating the injury, which can lead to scarring. It is important to avoid excessive oxidative stress during the wound healing period. Excessive accumulation of reactive oxygen species (ROS) has been found in the injured vocal folds of rats during the early phase of wound healing. Antioxidants proved to be useful in preventing the accumulation of ROS during the period with less scar formation in the long-term results. Oxidative stress is also revealed to contribute to aging of the vocal fold, in which the mucosa becomes thin and stiff with a reduction in vibratory capacity. The aged voice can be characterized as weak and breathy. It has been confirmed that ROS gradually increases in rat vocal fold mucosa with age, which may cause further damage to the vocal fold. Antioxidants have also proved effective in avoiding aging of the vocal fold in rat models. Recently, human trials have shown significant effects of the antioxidant Twendee X for maintaining the voice of professional opera singers. In conclusion, it is suggested that oxidative stress has a great impact on the damage or deterioration of the vocal folds, and the use of antioxidants is effective for preventing damage of the vocal fold and maintaining the voice.

Vocal Fold Polyps: A Scoping Review

OBJECTIVE

This review aims to summarize the current understanding of vocal fold polyp etiology, pathophysiology, and prognosis, as well as recent developments in management.

STUDY DESIGN

Scoping literature review.

REVIEW METHODS

OVID Medline, PubMed, Google Scholar, Conference Papers Index, and Cochrane Library were searched for publications within the last 5 years using terms including "vocal," "cord," "fold," and "polyp." All abstracts were screened. Relevant studies pertaining to the etiology, pathophysiology, diagnosis, management, and prognosis of vocal fold polyps (VFPs) were included for review.

RESULTS

Eight-hundred and sixty-five citations resulted from database review. Seven-hundred and thirty citations remained after the exclusion of duplicates. One hundred and ninety-three papers underwent abstract review, with 73 citations undergoing full-text review. Fifty-nine papers were included in the review.

CONCLUSIONS

VFPs are one of the most common subtypes of benign vocal fold lesions. Phonotrauma contributes significantly to the development of these lesions, with laryngopharyngeal reflux and smoking also contributing. Correct diagnosis relies on a careful history, stroboscopy, response to voice therapy, and, in some cases, intraoperative findings. Phonosurgery is a definitive means of treatment, though more recently, in-office procedures have demonstrated efficacy and are potentially less costly and less invasive treatment options. Treatment modalities can be tailored based on the type and size of the lesion, the patient's vocal needs, medical comorbidities, and initial response to voice therapy. Voice specialists can anticipate greater emphasis placed on minimally invasive office-based procedures for the management of vocal pathology.

Effect of nodule size and stiffness on phonation threshold and collision pressures in a synthetic hemilaryngeal vocal fold model

Synthetic vocal fold (VF) replicas were used to explore the role of nodule size and stiffness on kinematic, aerodynamic, and acoustic measures of voiced speech production. Emphasis was placed on determining how changes in collision pressure may contribute to the development of phonotrauma. This was performed by adding spherical beads with different sizes and moduli of elasticity at the middle of the medial surface of synthetic silicone VF models, representing nodules of varying size and stiffness. The VF models were incorporated into a hemilaryngeal flow facility. For each case, self-sustained oscillations were investigated at the phonation threshold pressure. It was found that increasing the nodule diameter increased the open quotient, phonation threshold pressure, and phonation threshold flow rate. However, these values did not change considerably as a function of the modulus of elasticity of the nodule. Nevertheless, the ratio of collision pressure to subglottal pressure increased significantly for both increasing nodule size and stiffness. This suggests that over time, both growth in size and fibrosis of nodules will lead to an increasing cycle of compensatory vocal hyperfunction that accelerates phonotrauma.

Bioreactors for Vocal Fold Tissue Engineering

It is estimated that almost one-third of the United States population will be affected by a vocal fold (VF) disorder during their lifespan. Promising therapies to treat VF injury and scarring are mostly centered on VF tissue engineering strategies such as the injection of engineered biomaterials and cell therapy. VF tissue engineering, however, is a challenging field as the biomechanical properties, structure, and composition of the VF tissue change upon exposure to mechanical stimulation. As a result, the development of long-term VF treatment strategies relies on the characterization of engineered tissues under a controlled mechanical environment. In this review, we highlight the importance of bioreactors as a powerful tool for VF tissue engineering with a focus on the current state of the art of bioreactors designed to mimic phonation in vitro. We discuss the influence of the phonatory environment on the development, function, injury, and healing of the VF tissue and its importance for the development of efficient therapeutic strategies. A concise and comprehensive overview of bioreactor designs, principles, operating parameters, and scalability are presented. An in-depth analysis of VF bioreactor data to date reveals that mechanical stimulation significantly influences cell viability and the expression of proinflammatory and profibrotic genes in vitro. Although the precision and accuracy of bioreactors contribute to generating reliable results, diverse gene expression profiles across the literature suggest that future efforts should focus on the standardization of bioreactor parameters to enable direct comparisons between studies. Impact statement We present a comprehensive review of bioreactors for vocal fold (VF) tissue engineering with a focus on the influence of the phonatory environment on the development, function, injury, and healing of the VFs and the importance of mimicking phonation on engineered VF tissues in vitro. Furthermore, we put forward a strong argument for the continued development of bioreactors in this area with an emphasis on the standardization of bioreactor designs, principles, operating parameters, and oscillatory regimes to enable comparisons between studies.

Clinical and surgical implications of intraoperative optical coherence tomography imaging for benign pediatric vocal fold lesions

INTRODUCTION

Benign vocal disorders in children include an extensive list of abnormalities creating a variety of debilitating levels of dysphonia. Precise delineation of the benign lesion type and margins may have significant public health implications in children. An innovative technology such as optical coherence tomography (OCT) is being explored to delineate pediatric benign laryngeal lesions. An accurate assessment of the subepithelial morphology may help towards tailoring more personalized therapeutic treatments. This study was established to highlight key morphological and optical features of benign pediatric laryngeal lesions using intraoperative OCT and to suggest clinical implications that arise from such optical imaging.

METHODS AND MATERIALS

This in vivo study was performed at Massachusetts Eye and Ear Infirmary. Intraoperative imaging was performed on twenty-five pediatric patients ranging from 1 year to 16 years of age presenting hoarseness. Three-dimensional OCT images of benign laryngeal lesions or a subsite of the lesion were acquired.

RESULTS

High-resolution OCT images of 25 patients with benign laryngeal lesions such as nodules, cysts, Reinke's edema, vocalis sulcus, and papilloma revealed distinct and specific morphological differences with normal tissue. Nodules show a symmetrical superficial remodeling of the vocal fold epithelial layer and the basement membrane. Cysts have oval-like shape and are either superficial or deeply located in the lamina propria. Sulcus vocalis OCT imaging allows characterizing if the lesion is shallow or deep according to Ford's classification system. Reinke's edema of the mucosa can be observed and quantified, which may lead to suspicion on the underlying social and medical conditions. Finally, the ability to assess margins and depth of invasion of papilloma lesions is demonstrated, raising the possibility to use OCT with angiolytic lasers for patient-tailored treatments.

CONCLUSIONS

OCT imaging of benign pediatric vocal lesions is promising as it could improve preoperative decision-making and possibly peroperative imaging-guidance for patient-tailored treatments. An assessment of the optical contrast between healthy and abnormal tissue may help towards a more qualitative and quantitative approach to current standard care, especially when diagnosis remains unclear.

Efficacy of Intralesional Steroid Injection in Small Benign Vocal Fold Lesions

OBJECTIVES

The present study was conducted to study the efficacy of intralesional steroid (ILS) injection in small benign vocal fold lesions and compare the outcomes with microlaryngeal surgery in terms of improvement in symptoms and reduction in lesion size.

METHODS

The current randomized control trial was conducted in the Department of Otolaryngology at the Postgraduate Institute of Medical Education and Research in Chandigarh between 2014 and 2015. The clinical diagnosis was based on appearance of the lesion during endoscopy and the mucosal vibration pattern. Subjects with lesions of size less than or equal to 5 mm were included.

RESULTS

A total of 29 subjects were included in the study and 15 (nine men and six women) of them were randomized to receive ILS injection. Fourteen (13 men and one woman) were randomized to the second group to receive initial microlaryngeal surgery. We noted significant reduction in the size of the lesion among subjects undergoing ILS injection at 12 weeks (1.11 + 1.45 mm) as compared to baseline (2.63 + 1.28 mm) with no recurrence.

CONCLUSIONS

ILSs are effective in reducing size of lesion and also improve acoustic parameters, perceptual analysis, and grade of dysphonia in patients presenting with small benign vocal cord lesions.

HPV16 DNA and integration in normal and malignant epithelium: implications for the etiology of laryngeal squamous cell carcinoma

Background

Molecular evidence suggests that human papillomavirus (HPV) has a role in the etiology of oropharyngeal squamous cell carcinoma. However, the role of HPV in laryngeal squamous cell carcinoma (LSCC) is unclear.

Patients and methods

We conducted a case–control study using tumor tissue specimens from 300 LSCC patients and vocal cord polyp specimens from 300 cancer-free controls. HPV genotype, HPV16 viral load and viral integration status, and p16 expression were determined.

Results

The prevalence of HPV (all types) was higher in cases than controls [21 (7.0%) versus 10 (3.3%), adjusted odds ratio (aOR) 2.37, 95% CI 1.08–5.21]. The prevalence of HPV16 was higher in cases than controls [20 (6.7%) versus 8 (2.7%), aOR 2.84, 95% CI 1.21–6.68]. The risk of LSCC associated with HPV16 DNA positivity was even higher in patients aged 55 years or younger (aOR 3.52, 95% CI 1.07–11.54), males (aOR 4.74, 95% CI 1.33–16.90), never-smokers (aOR 5.57, 95% CI 1.41–22.10), and never-drinkers (aOR 3.72, 95% CI 1.09–12.72). HPV DNA was partly or fully integrated in all 20 HPV16-positive cases but was episomal in all 8 HPV16-positive controls; however, the HPV16-positive cases and controls had similar viral loads (P = 0.28). P16 immunostaining was positive in 31 of the 300 cases (10.3%) and negative in all 300 controls.

Conclusion

These results suggest that prior infection with HPV16 may play a role in the etiology of some LSCC. This larger case–control study will offer for the first time the possibility to address in depth the understanding of a tissue-specific role of HPV in laryngeal carcinogenesis. Further studies with larger samples are needed to confirm these findings.

Histologic Characterization of Rat Vocal Fold Scarring

This study aimed to clarify the characteristics of rat vocal fold scarring by examining the alteration of key components in the extracellular matrix: hyaluronic acid, collagen, and fibronectin. Under monitoring with a 1.9-mm-diameter telescope, unilateral vocal fold stripping was performed, and larynges were harvested at 2, 4, 8, and 12 weeks after operation. The vocal folds were histologically analyzed with Alcian blue stain, trichrome stain, and immunofluorescence of collagen type I, collagen type III, and fibronectin. The scarred vocal folds showed less hyaluronic acid and more collagen types I and III than did the controls at all time points. Type III was stable for 12 weeks, while type I declined until 8 weeks and thereafter remained unchanged. Fibronectin increased for 4 weeks and then decreased; it was close to the control level at 8 and 12 weeks. These results suggest that the tissue remodeling process in scarred vocal folds slows down around 2 months after wounding.

Quality-of-Life Outcomes following Laryngeal Endoscopic Surgery for Nonneoplastic Vocal Fold Lesions

Preservation of the vocal fold cover during laryngeal surgery should optimize vocal outcomes for patients with benign glottal lesions. The aim of this study was to evaluate changes in the quality of life, perceptual voice evaluation, and acoustic and aerodynamic measures of patients before and after endoscopic laryngeal microsurgery for true vocal fold cysts, polyps, and scarring. Preoperative and postoperative Voice Handicap Index (VHI) scores, Short Form 36 scores, and perceptual, acoustic, and aerodynamic voice measures were obtained prospectively from 42 patients who underwent phonomicrosurgery from February 2000 through May 2003. The mean (+/-SD) preoperative VHI was 49.6 +/- 21. The mean postoperative VHI score at a minimum of 3 months after surgery decreased to 26.8 +/- 21 (p < .001). When divided by lesion type, VHI scores improved significantly after surgery for vocal fold polyps and cysts. Although patients with vocal fold scarring demonstrated improvement in VHI scores after surgery, statistical significance was not achieved. For the entire group, the Short Form 36 scores were not significantly different from US norms either before or after operation. The acoustic data showed statistically significant decreases in jitter (2.05% to 1.26%), shimmer (7.06% to 4.03%), and noise-to-harmonics ratio (0.18 to 0.13) after surgery (p < .05) in female patients. The upper pitch limit increased after surgery in women (495.3 Hz to 654.9 Hz, p < .001). These results indicate that the voice-related quality of life and some acoustic parameters improve significantly for patients who have undergone laryngeal microsurgery for vocal fold cysts and polyps. Vocal fold scarring remains a difficult clinical problem with less favorable outcomes following surgical treatment in this patient set.

Utility of Voice Therapy in the Management of Vocal Fold Polyps and Cysts

OBJECTIVE: To evaluate the efficacy of voice therapy in the management of vocal fold polyps and cysts.

STUDY DESIGN AND SETTING: Retrospective review of vocal fold cysts and polyps undergoing voice therapy in a tertiary care center. Symptom resolution or persistence resulting in surgical intervention was the main outcome measure.

RESULTS: Fifty-seven patients were identified, of which 49.1% achieved symptom resolution with voice therapy alone. Patients with complete glottal closure and muscle tension dysphonia did not have a better response than those with incomplete glottal closure and without muscle tension dysphonia ( P = 0.1, χ 2 , respectively). Patients with translucent polyps more commonly responded to voice therapy than fibrotic, hyaline, or hemorrhagic polyps, 81.8% versus 15.4% and 25.0% response rate, respectively ( P = 0.002, χ 2 ).

CONCLUSIONS: Voice therapy is an effective treatment modality for vocal fold polyps and cysts.

SIGNIFICANCE: A multidisciplinary approach including a trial of voice therapy is warranted.

Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

Objective. Conventional surgical techniques of laryngomicrosurgery (LMS) on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL), which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73), and there were 20 males and 19 females (17 professional voice users). In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps.

A comparative histopathological study of vocal fold polyps in smokers versus non-smokers

BACKGROUND

A large proportion of patients with vocal fold polyps are cigarette smokers. However, prior to this report no comparative study of polyp histopathology in smokers versus non-smokers had been performed.

METHODS

A prospective histopathological study of vocal fold polyps excised from 29 patients was undertaken. This comprised a comparative analysis of polyp histopathology in smokers versus non-smokers and a review of the pertinent literature.

RESULTS

Vocal fold polyps were larger in smokers than in non-smokers. Histopathological features significantly associated with the polyps of smokers versus those of non-smokers were increased keratinisation, dysplasia, a basement membrane thinning and hyaline degeneration.

CONCLUSION

Cigarette smoke has an injurious effect on vocal fold polyp epithelium and leads to increased hyaline degeneration in polyps.

Lipopolysaccharide responsiveness in vocal fold fibroblasts

Background

Vocal fold fibroblast’s (VFF) strategic location in the lamina propria and their ability to respond to external stimuli by producing inflammatory molecules suggest their possible direct involvement in innate immunity. Toll-like receptors (TLRs) are an essential signaling component to this response, as they allow for recognition of various microorganisms, leading to subsequent induction of pro-inflammatory genes. The objective of this study was to elucidate the role of VFF in the host immune response and subsequent influence on inflammatory cytokine secretion.

Methods

VFF derived from polyp, scar, and normal tissue were treated with 5 μg/ml lipopolysaccharide (LPS). TLR1 through 9, CD14, and MD-2 were measured during stable conditions by polymerase chain reaction (PCR). Expression of TLR4 and IL-1R type-1 genes were quantified after 24 hrs LPS stimulation by reverse transcription-PCR. LPS responsiveness was determined by NF-κB nuclear translocation as measured by subunit p65 expression in nucleus with immunocytochemistry. Downstream effects were confirmed with immunoassay measuring IL-8 concentrations in supernatant after 8 hrs.

Results

All VFFs constitutively expressed TLR1 to 6, TLR9, CD14, and MD-2 mRNA. Polyp VFF exhibited significantly higher TLR4 transcript levels (p < 0.001) in comparison to scar and normal VFF. LPS stimulated scar and polyp VFF exhibited increased levels of p65 in the nucleus (p < 0.01) and secreted greater IL-8 protein (p < 0.0001) compared to normal VFF.

Conclusion

VFF constitutively express genes for the receptors essential to the host immune response. Scar and polyp VFF produced greater LPS responsiveness resulting in over-activated inflammatory patterns. These findings support VFF role in the pathogenesis of inflammatory vocal fold disorders and suggests their presence in the wound bed could lead to chronic inflammation.

An in vivo study of composite microgels based on hyaluronic acid and gelatin for the reconstruction of surgically injured rat vocal folds

PURPOSE The objective of this study was to investigate local injection with a hierarchically microstructured hyaluronic acid-gelatin (HA-Ge) hydrogel for the treatment of acute vocal fold injury using a rat model. METHOD Vocal fold stripping was performed unilaterally in 108 Sprague-Dawley rats. A volume of 25 μl saline (placebo controls), HA-bulk, or HA-Ge hydrogel was injected into the lamina propria (LP) 5 days after surgery. The vocal folds were harvested at 3, 14, and 28 days after injection and analyzed using hematoxylin and eosin staining and immunohistochemistry staining for macrophages, myofibroblasts, elastin, collagen type I, and collagen type III. RESULTS The macrophage count was statistically significantly lower in the HA-Ge group than in the saline group (p < .05) at Day 28. Results suggested that the HA-Ge injection did not induce inflammatory or rejection response. Myofibroblast counts and elastin were statistically insignificant across treatment groups at all time points. Increased elastin deposition was qualitatively observed in both HA groups from Day 3 to Day 28, and not in the saline group. Significantly more elastin was observed in the HA-bulk group than in the uninjured group at Day 28. Significantly more collagen type I was observed in the HA-bulk and HA-Ge groups than in the saline group (p < .05) at Day 28. The collagen type I concentration in the HA-Ge and saline groups was found to be comparable to that in the uninjured controls at Day 28. The concentration of collagen type III in all treatment groups was similar to that in uninjured controls at Day 28. CONCLUSION Local HA-Ge and HA-bulk injections for acute injured vocal folds were biocompatible and did not induce adverse response.

Recovery of vibratory function after vocal fold microflap in a rabbit model

OBJECTIVES/HYPOTHESIS

The purpose of this study was to evaluate the return of vibratory function and restoration of vibration amplitude and symmetry after vocal fold microflap surgery.

STUDY DESIGN

Prospective in vivo animal model.

METHODS

Microflap surgery was performed on 30 New Zealand white breeder rabbits. The left vocal fold received a 3-mm epithelial incision and mucosal elevation, while the contralateral vocal fold was left intact to serve as an internal control. Quantitative analysis of amplitude ratio and lateral phase difference were measured using high-speed laryngeal imaging at a frame rate of 10,000 frames per second from animals undergoing evoked phonation on postoperative days 0, 1, 3, 5, and 7.

RESULTS

Quantitative measures revealed a significantly reduced amplitude ratio and lateral phase difference on day 0 after microflap. These impairments of vibratory function on day 0 were associated with separation of the vocal fold's body-cover layer. Amplitude ratio increased significantly by day 3 after microflap, with further increases in vibration amplitude on days 5 and 7. While the amplitude ratio improved significantly on day 3, lateral phase difference decreased significantly on day 3, and returned to normal on days 5 and 7.

CONCLUSIONS

High-speed laryngeal imaging was used to investigate the natural time course of postmicroflap recovery of vibratory function. Results revealed the restoration of vibration amplitude and lateral phase difference by days 3 to 7 after microflap. The time period of improved vibratory function observed in this study coincides with the end of the well-documented inflammatory phase of vocal fold wound repair.

LEVEL OF EVIDENCE

N/A.

Clinical practice: vocal nodules in dysphonic children

Common among children, vocal symptoms are a cause of concern for parents who seek elucidation of their diagnosis and treatment. Vocal nodules are the major cause of dysphonias in children and are related to vocal abuse. We conducted a literature review considering clinical, physiopathological, epidemiological, and histological aspects of vocal nodules, as well as diagnostic methods, highlighting the main studies addressing this issue. The controversial points of treatments were also discussed.

Biochemical basis of vocal fold mobilization after microflap surgery in a rabbit model

OBJECTIVES/HYPOTHESIS

To investigate phonation-related extracellular matrix (ECM) changes in the vocal fold lamina propria after microflap surgery using an in vivo rabbit phonation model.

STUDY DESIGN

Prospective animal study.

METHODS

Twenty-four New Zealand White rabbits were used in this study. Quantitative polymerase chain reaction and immunohistochemistry were used to investigate alterations in vocal fold ECM proinflammatory and profibrotic gene, and protein expression from a control group of animals receiving a microflap without phonation and a separate group of animals receiving experimentally induced phonation on postmicroflap days 0, 3, and 7.

RESULTS

IHC demonstrated the highest concentration of CD45 in vocal folds on postoperative day 0. Staining for CD45 was absent by postoperative day 7, with no differences in CD45 staining between groups. Fibronectin gene expression increased significantly on postoperative day 3 in the control and experimentally induced phonation groups, with maximal staining of fibronectin around the microflap incision on postoperative day 7. No alterations in cyclooxygenase-2, interleukin-1β, and transforming growth factor-β1 gene expression were observed between groups.

CONCLUSIONS

Results of the present study revealed an acute inflammatory response in the vocal fold at the time of microflap (day 0) and up to 3 days post-microflap. By post-operative day 3, staining of CD45 positive cells decreased, with essentially no evidence of inflammation by post-operative day 7. With the end of the acute inflammatory response occurring around day 3, these data may provide support for mobilizing tissue after inflammation has subsided and the process of active tissue remodeling has ensued (days 3-7).

LEVEL OF EVIDENCE

N/A.

Clinical diagnosis and histological analysis of vocal nodules and polyps

Recent studies emphasize the importance of the clinical-histology correlation in laryngeal pathologies.

Objective

To compare the ENT diagnosis with the pathology diagnosis one of 132 surgical specimens, from 119 patients with vocal nodules and polyps.

Method

Retrospective study. We investigated the paraffin blocks corresponding to the lesions of the operated patients. We made new histology cross-sections, totaling 396 new slides, divided into three groups: hematoxylin and eosin, Gomori trichrome and PAS. We analyzed the following histological parameters: epithelium, lamina propria, basement membrane, vascular changes. We compared the laryngological and pathological diagnoses, and we did the statistical analysis, checking the predominant histological aspects in each lesion.

Results

There was an agreement between the clinical and pathological diagnoses in 123 (93.18%) of 132 lesions analyzed (42.42% nodules and 50.76% polyps). In the histological parameters we found: epithelial changes such as nodules hyperplasia (82.14%) and polyp atrophy (31.34%). Lamina propria: edema in polyps (71.43%), fibrosis in the nodules (57.14%). Basement membrane: thickened nodules (100%), thin/no change in polyps (100%). There was a predominance of vascular changes in the polyps.

Conclusion

We found a high correlation between the ENT diagnosis and the pathology report. Histopathologically, the nodules presented with predominantly epithelial changes, lamina propria and basement membrane fibrosis, while the polyps by changes strictly on the lamina propria and vascular aspects.

Current Understanding and Future Directions for Vocal Fold Mechanobiology

The vocal folds, which are located in the larynx, are the main organ of voice production for human communication. The vocal folds are under continuous biomechanical stress similar to other mechanically active organs, such as the heart, lungs, tendons and muscles. During speech and singing, the vocal folds oscillate at frequencies ranging from 20 Hz to 3 kHz with amplitudes of a few millimeters. The biomechanical stress associated with accumulated phonation is believed to alter vocal fold cell activity and tissue structure in many ways. Excessive phonatory stress can damage tissue structure and induce a cell-mediated inflammatory response, resulting in a pathological vocal fold lesion. On the other hand, phonatory stress is one major factor in the maturation of the vocal folds into a specialized tri-layer structure. One specific form of vocal fold oscillation, which involves low impact and large amplitude excursion, is prescribed therapeutically for patients with mild vocal fold injuries. Although biomechanical forces affect vocal fold physiology and pathology, there is little understanding of how mechanical forces regulate these processes at the cellular and molecular level. Research into vocal fold mechanobiology has burgeoned over the past several years. Vocal fold bioreactors are being developed in several laboratories to provide a biomimic environment that allows the systematic manipulation of physical and biological factors on the cells of interest in vitro. Computer models have been used to simulate the integrated response of cells and proteins as a function of phonation stress. The purpose of this paper is to review current research on the mechanobiology of the vocal folds as it relates to growth, pathogenesis and treatment as well as to propose specific research directions that will advance our understanding of this subject.

Feasibility and acute healing of vocal fold microflap incisions in a rabbit model

OBJECTIVES/HYPOTHESIS

The purpose of this study was to investigate the feasibility of performing mucosal elevation of a vocal fold microflap in a rabbit model and to measure the acute healing of rabbit microflap incisions compared to control vocal folds.

STUDY DESIGN

Prospective animal study.

METHODS

Ten New Zealand white rabbits were used in this study. All rabbits received a 3-mm incision through the epithelium of one vocal fold using a sickle knife and mucosal elevation through this incision using a microlaryngeal fine-angled spatula. The contralateral vocal fold was left intact to serve as an internal control. Student t tests were used to investigate differences in epithelial thickness, immunohistochemical staining of CD45, and inflammatory and profibrotic gene expression between vocal folds undergoing microflap and control.

RESULTS

Exposure of the rabbit larynx was achieved, allowing for the identification of a surgical plane and the creation of a microflap and elevation of the vocal fold mucosa. Hematoxylin-and-eosin staining revealed no significant differences in epithelial thickness, immunohistochemistry for CD45 showed no significant differences in CD45-positive cells, and quantitative polymerase chain reaction revealed no significant differences in interleukin-1β, transforming growth factor β-1, or cyclooxygenase-2 gene expression between vocal folds undergoing microflap and control.

CONCLUSIONS

We demonstrate the feasibility of vocal fold microflap surgery in a rabbit model. With the advantage of greater access to primers and antibodies for molecular biologic studies, the application of the microflap technique in a small-animal model such as rabbit has broad implications for future experimental investigations in laryngology.

Reinkes' edema: immunoexpression study of fibronectin, laminin and collagen IV in 60 cases by immunohistochemical techniques

Reinke's edema is chronic laryngeal disease in which the superficial layer of the lamina propria is expanded by thick mucus, giving it a gelatin aspect. The disease is directly related to smoking and more frequent in women, who end up having a lower tone of voice. Its histological characteristics cannot always distinguish it from other benign lesions of the larynx for which additional histological techniques are necessary.

Aim

to study the immunoexpression of fibronectin, collagen IV and laminin in Reinke's edema by immunohistochemical technique. Prospective study.

Materials and methods

histological blocks of 60 cases of surgical Reinke's edema were saved, submitted to new cross-sections and to immunohistochemical reactions for fibronectin, laminin and collagen IV by the Avidin-Biotin-Peroxidase method. Fragments of five normal vocal folds were used as control, removed during autopsy. All patients were chronic smokers and adults– 50 women and 10 men.

Results

the immunoexpression of fibronectin, collagen IV and laminin was more important in the endothelium of blood vessels (68.33%, 76.66%, 73.33%, respectively) and less relevant in the basement membrane (25.0%, 5.0% and 3.3%, respectively).

Conclusions

the immunoexpression of fibronectin, laminin and of collagen IV in the basal membrane of Reinke's edema was not relevant, with a predominance of these antibodies in the endothelium of blood vessels.

Vocal polyps: clinical, morphological, and immunohistochemical aspects

OBJECTIVES

To study the clinical, morphological, and immunohistochemical characteristics of vocal polyps.

STUDY DESIGN

Prospective and retrospective.

METHODS

Clinical study: 76 medical charts from patients with polyps were reviewed. Histology study: in 42 slides from surgical specimens, the following were analyzed: epithelium, basal membrane, and lamina propria. In the transmission and scanning electron microscopy (TEM and SEM) studies, eight new cases of polyps were included. An immunohistochemical study was carried out in the 42 specimens, using antibody antifibronectin, antilaminin, and anticollagen IV.

RESULTS

Genders--43% males and 57% females; age range--between 21 and 40 years (36.85%); and between 41 and 60 years of age (51.31%); smoking and drinking-reported by 39 and 15 patients, respectively; associated symptoms-vocal abuse (61%), gastroesophageal (47%), and nasosinusal symptoms (32%); occupation--teachers (24.0%) and maids (18.0%). Histology--epithelial hyperplasia (31.71%), hyperkeratosis, (14.28%), edema (100%), vessel proliferation (92.86%), and congestion (83.33%). SEM--reduction in mucous lacing and increase in desquamating cells. TEM--hyperplastic epithelium, enlargement of the intercellular junctions, dense subepithelial network of collagen and basal membrane with adhesion loss. Immunohistochemistry--greater immunoexpression of fibronectin, laminin, and collagen IV around the vessels.

CONCLUSIONS

In vocal polyps, the morphological analyses show lamina propria with edema, vessel proliferation and inflammation, basement membrane with adhesion loss in some areas and dense network of subepithelial collagen. Immunohistochemistry techniques identify pigmentation of the antibodies anti-fibronectin, anti-laminin, and anti-collagen IV in the endothelium of blood vessels.

Vocal fold nodules: morphological and immunohistochemical investigations

The objective of this study was to investigate the morphological and immunohistochemical characteristics of vocal fold nodules. The study design was prospective and retrospective. For the histological study, we reviewed 15 slides from the surgical cases of vocal fold nodules, in which we analyzed epithelium, basal membrane (bm), and lamina propria. For the transmission and scanning electron microscopy (TEM, SEM) studies, five new cases on vocal fold nodules were included. Immunohistochemistry study was carried out in the 15 specimens, using antifibronectin, antilaminin, and anticollagen IV antibodies. The main histological alterations were epithelial hyperplasia (73.33%), basement membrane thickening (86.66%), edema, and fibrosis (93.33%). SEM--reduction in mucous lacing and increase in the desquamating cells, without epithelial erosion. TEM--hyperplasia of the epithelium, enlargement of the intercellular junctions, which was filled by fluid, subepithelial thickening of the lamina reticularis, and break points in the basal membrane. Immunohistochemistry--we identified greater immunoexpression of fibronectin on the basal membrane, on the lamina propria, and around the vessels. Antilaminin and anticollagen IV antibodies showed higher pigmentation on the endothelium of the vessels than that on the basal membrane. In vocal fold nodules, combined assessment using light microscopy, electron microscopy, and immunohistochemistry can reveal important morphological details useful in characterizing these lesions.

Unsuspected intraoperative finding of structural abnormalities associated with vocal fold polyps

OBJECTIVES

To report the findings of unsuspected underlying concurrent abnormalities of the vocal fold (VF) associated with polyps.

STUDY DESIGN AND SETTING

Retrospective chart review at tertiary teaching institution.

SUBJECTS AND METHODS

Operative and clinical notes of 81 adults submitted to suspension laryngoscopy for vocal fold polyp (VFP) excision from 1998 to 2007, which had no previous report of associated structural abnormalities.

RESULTS

Associated lesions were described in 54 patients (67%) (35 contralateral, 16 ipsilateral, and three bilateral): 18 reactive nodules, 21 sulcus vocalis, five cysts, two microwebs, and eight capillary ectasias. A positive correlation was found between the presence of polyps and associated structural abnormalities (r=0.0035; P<0.05).

CONCLUSIONS

The high incidence of concurrent previously unsuspected VF lesions suggests that either these minor underlying anatomical deviations render the VF more vulnerable to vocal abuse, or that phonotrauma may cause a number of VF lesions that can lead to dysphonia.

Matrix Metalloproteinases (MMP-2 and MMP-9) and Cyclooxygenase-2 (COX-2) Expressions in Vocal Fold Polyps

The objective of this study was to investigate the roles of matrix metalloproteinases (MMP-2, MMP-9) and cyclooxygenase-2 (COX-2) in the pathogenesis of vocal fold polyps (VFPs). In this study, 20 VFPs and 8 normal vocal fold (VF) specimens were obtained from subjects undergoing surgery. Staining intensities were semiquantitatively assessed and statistically analyzed. Significant increases were observed in the expressions of MMP-2, MMP-9, and COX-2 in stromal spindle cells (P=0.00) and vascular wall (P=0.04, P=0.00, P=0.00) of VFPs compared with normal VFs. MMP-2 expression in surface epithelium basal cells (P=0.00) of VFPs showed enhancement compared with normal vocal folds, whereas MMP-9 and COX-2 expressions showed no significant differences. Our study showed that gelatinases and COX-2 may play a role in the development of VFPs. This is the first study to document the expression of gelatinases and COX-2 in VFPs.

A patient-specific in silico model of inflammation and healing tested in acute vocal fold injury

The development of personalized medicine is a primary objective of the medical community and increasingly also of funding and registration agencies. Modeling is generally perceived as a key enabling tool to target this goal. Agent-Based Models (ABMs) have previously been used to simulate inflammation at various scales up to the whole-organism level. We extended this approach to the case of a novel, patient-specific ABM that we generated for vocal fold inflammation, with the ultimate goal of identifying individually optimized treatments. ABM simulations reproduced trajectories of inflammatory mediators in laryngeal secretions of individuals subjected to experimental phonotrauma up to 4 hrs post-injury, and predicted the levels of inflammatory mediators 24 hrs post-injury. Subject-specific simulations also predicted different outcomes from behavioral treatment regimens to which subjects had not been exposed. We propose that this translational application of computational modeling could be used to design patient-specific therapies for the larynx, and will serve as a paradigm for future extension to other clinical domains.

Vocal nodules and edema may be due to vibration-induced rises in capillary pressure

HYPOTHESIS

Vocal fold vibration may physically raise intravascular pressure to levels high enough to damage capillaries and result in leakage of erythrocytes. This type of injury is commonly seen in benign vocal fold lesions and is not well explained.

STUDY DESIGN

Theoretical, retrospective.

METHODS

The relationship of intravascular pressure to vibration frequency and amplitude is derived and confirmed with a physical blood vessel model, then applied to published human measurements to estimate human intravascular pressures.

RESULTS

Vocal fold intravascular pressure is predicted to have a quadratic dependence on both frequency and amplitude. During speaking, the pressure may rise to over 20 cmH2O, and may reach levels far higher for screaming and singing. Such pressure magnitudes are known to trigger inflammatory cascades and can lead to fluid leakage. They also have the potential for pharmacologic control with beta-agonists.

CONCLUSIONS

Intravascular pressure likely rises significantly during vocal fold vibration and may lead to the type of injury seen in benign vocal fold lesions. The results support voice therapy aimed at reducing vibratory amplitude. More vibratory amplitude measurements need to be performed in a wider range of subjects before the full range of human vocal fold vascular pressures can be estimated.

Airway obstruction: a rare complication of benign vocal fold polyps

OBJECTIVES

Benign laryngeal polyps usually present with hoarseness and dysphonia. There have been a few reported cases, however, of polyps that caused airway obstruction. Herein we present our series of obstructing laryngeal polyps.

METHODS

A retrospective review was performed of all patients with benign laryngeal lesions treated by the senior author (A.M.S.S.) between 1997 and 2006. Patients who presented with airway obstruction were identified. Detailed information was recorded on the demographics, presenting signs and symptoms, and surgical procedures. Preoperative and postoperative laryngoscopies were reviewed.

RESULTS

Ten patients were identified. There were 7 women and 3 men. The mean age was 49 years (range, 34 to 64 years). All had a history of vocal abuse and smoking, with a mean of 35.2 pack-years (range, 7.5 to 112.5 pack-years). All underwent microlaryngoscopy with excision of the lesions. Jet ventilation or a small endotracheal tube was used to secure the airway. The mean follow-up of 9 patients was 71.2 days (range, 25 to 208 days); 1 patient was lost to followup. An excellent airway and improved voice was achieved in all. Forty-four percent (4 of 9) had persistent dysphonia and a decreased mucosal wave after the operation.

CONCLUSIONS

Benign laryngeal polyps may present with airway obstruction and thus should be included in the differential diagnosis of stridor. Endoscopic treatment can result in an excellent airway, but dysphonia may persist in some cases.

Experimentally induced phonation increases matrix metalloproteinase-1 gene expression in normal rabbit vocal fold

OBJECTIVES

An in vivo rabbit model was used to study the effect of 3 hours of experimentally induced phonation on messenger RNA expression of the normal vocal fold.

STUDY DESIGN

Prospective; animal model.

SUBJECTS AND METHODS

Ten rabbits received experimental phonation for 3 hours, followed by 1 hour of recovery. A separate group of 5 rabbits served as no-phonation controls. We measured messenger RNA expression of matrix metalloproteinase-1, MMP-9, and interleukin-1beta using real-time reverse-transcribed polymerase chain reaction. Gene expression ratios from phonation and control animals were assessed with the Mann-Whitney U test.

RESULTS

Phonation (77 +/- 3 dB; 429 +/- 141 Hz) resulted in increased matrix metalloproteinase-1 gene expression from rabbits receiving experimental phonation compared with controls, and a nonsignificant increase in matrix metalloproteinase-9 and interleukin-1beta gene expression.

CONCLUSION

Matrix metalloproteinases play a role in maintaining tissue homeostasis. Investigation of cellular responses to experimental phonation may provide insight into how matrix metalloproteinases and other extracellular matrices contribute to maintenance of the vocal fold and development of pathology.

Vocal fold masses

Vocal fold masses are often complex in nature and can have a devastating result on the professional voice. These lesions are usually multifactorial with synergistic contributions over time from voice use demands and technique, medical conditions, medications, and the environment. General categories of benign vocal fold masses in professional voice include nodules, polyps, and cysts, but other pathology should be considered, such as reactive lesions, intracordal scarring, feeding varices, and reparative granuloma. A perspective on these issues is essential for proper diagnosis and management. Video procedures for nodule and polyp surgery accompany this content online.

Atomic Force Microscopy Investigation of Vocal Fold Collagen

OBJECTIVES

Collagen is an important constituent of the vocal fold extracellular matrix and is necessary for providing tensile strength and maintaining tissue geometry. Traditional investigations of vocal fold collagen using light and electron microscopy do not provide information on the organization and mechanical properties of collagen in native topographic state. The primary objective of this study was to use Atomic Force Microscopy (AFM) to examine the surface characteristics and organization of collagen in the deep layer of the lamina propria at nanoscale resolution.

STUDY DESIGN

Experimental in vitro design.

METHODS

Freshly dissected porcine vocal folds were mounted on AFM discs and imaged under contact and tapping mode to obtain information on topographic distribution of collagen.

RESULTS

AFM imaging of the deep layer of the lamina propria revealed dense, abundant collagen fibers with a characteristic banding pattern. The distribution of collagen was heterogeneous, with both hydrophilic and hydrophobic regions within a sample.

CONCLUSIONS

AFM offers a useful tool to obtain topographic information about biologic samples at nanoscale resolution with minimal sample preparation. Mapping the topography and mechanical properties of vocal fold collagen is necessary for designing rheologically compatible bioimplants for the treatment of dysphonia resulting from vocal fold scarring and bowing.

Paxillin modulates squamous cancer cell adhesion and is important in pressure-augmented adhesion

Paxillin is an adapter protein regulating signaling and focal adhesion assembly that has been linked to malignant potential in many malignancies. Overexpression of paxillin has been noted in aggressive tumors. Integrin-mediated binding through the focal adhesion complex is important in metastatic adhesion and is upregulated by extracellular pressure in malignant colonocytes through FAK and Src activation. Neither head and neck cancers nor paxillin have been studied in this regard. We hypothesized that paxillin would play a role in modulating squamous cancer adhesion both at baseline and under conditions of increased extracellular pressure. Using SCC25 tongue squamous cancer cells stably transfected with either an empty selection vector or paxillin expression and selection vectors, we studied adhesion to collagen, paxillin, FAK, and Src expression and phosphorylation in cells maintained for 30 min under ambient or 15 mmHg increased pressure conditions. Paxillin-overexpressing cells exhibited adhesion 121 +/- 2.9% of that observed in vector-only cells (n = 6, P < 0.001) under ambient pressure. Paxillin-overexpression reduced FAK phosphorylation. Pressure stimulated adhesion to 118 +/- 2.3% (n = 6, P < 0.001) of baseline in vector-only cells, similar to its effect in the parental line, and induced paxillin, FAK, and Src phosphorylation. However, increased pressure did not stimulate adhesion or phosphorylate paxillin, FAK, or Src further in paxillin-overexpressing cells. Metastasizing squamous cancer cell adhesiveness may be increased by paxillin-overexpression or by paxillin activation by extracellular pressure during surgical manipulation or growth within a constraining compartment. Targeting paxillin in patients with malignancy and minimal tumor manipulation during surgical resection may be important therapeutic adjuncts.

Differential gene expression profiling of vocal fold polyps and Reinke's edema by complementary DNA microarray

OBJECTIVES

Our purpose was to determine whether complementary DNA (cDNA) microarray analysis (MA) can establish distinct gene expression profiles for 2 phenotypically similar vocal fold lesions: Reinke's edema (RE) and polyps. Established transcript profiles can provide insight into the molecular and cellular processes involved in these diseases.

METHODS

Eleven RE specimens and 17 polyps were analyzed with MA for 8,745 genes. Further MA profiling was attempted within each lesion group to identify molecular markers for reflux exposure and smoking. Prediction analysis was used to predict lesion classification for 2 unclassified samples. A real-time polymerase chain reaction was performed to corroborate MA transcript levels for selected significant genes.

RESULTS

Sixty-five genes were found to differentiate RE and polyps (p = .0088). For RE, 19 genes were differentiated for reflux exposure (p = .016). No genes were found to differentiate smokers from nonsmokers. For polyps, no genes were found to differentiate for reflux (p = .16) and smoking (p = .565). Categorization of unclassified lesions was possible with a minimum of 13 genes.

CONCLUSIONS

We demonstrate the feasibility of benign lesion classification based on MA. Microarray analysis is useful not only for improving diagnosis and classification of such lesions, but also for potentially generating prognostic indicators and targets for therapy.