Frey syndrome is a common sequela of parotidectomy, and although it is not frequently manifested clinically, it can cause significant morbidity for those affected. Frey syndrome results from ...synkinetic autonomic reinnervation by transected postganglionic parasympathetic nerve fiber within the parotid gland to the overlying sweat glands of the skin. Many surgical techniques have been proposed to prevent the development of Frey syndrome. For those who develop clinical symptoms of Frey syndrome, objective testing can be performed with a Minor starch-iodine test. Some of the current methods to prevent and treat symptomatic Frey syndrome are reviewed.
Objective Laryngotracheal stenosis (LTS) is a fibrotic process that narrows the upper airway and has a significant impact on breathing and phonation. Iatrogenic injury from endotracheal and/or ...tracheostomy tubes is the most common etiology. This study investigates differences in LTS etiologies as they relate to tracheostomy dependence and dilation interval. Study Design Case series with chart review. Setting Single-center tertiary care facility. Subjects and Methods Review of adult patients with LTS was performed between 2004 and 2015. The association of patient demographics, comorbidities, disease etiology, and treatment modalities with patient outcomes was assessed. Multiple logistic regression analysis and Kaplan-Meier analysis were performed to determine factors associated with tracheostomy dependence and time to second procedure, respectively. Results A total of 262 patients met inclusion criteria. Iatrogenic patients presented with greater stenosis ( P = .023), greater length of stenosis ( P = .004), and stenosis farther from the vocal folds ( P < .001) as compared with other etiologies. Iatrogenic patients were more likely to be African American, use tobacco, and have obstructive sleep apnea, type II diabetes, hypertension, chronic obstructive pulmonary disease, or a history of stroke. Iatrogenic LTS (odds ratio OR = 3.1, 95% confidence interval 95% CI = 1.2-8.2), Cotton-Myer grade 3-4 (OR = 2.6, 95% CI = 1.1-6.4), and lack of intraoperative steroids (OR = 2.9, 95% CI = 1.2-6.9) were associated with tracheostomy dependence. Nonsmokers, patients without tracheostomy, and idiopathic LTS patients had a significantly longer time to second dilation procedure. Conclusion Iatrogenic LTS presents with a greater disease burden and higher risk of tracheostomy dependence when compared with other etiologies of LTS. Comorbid conditions promoting microvascular injury-including smoking, COPD, and diabetes-were prevalent in the iatrogenic cohort. Changes in hospital practice patterns to promote earlier tracheostomy in high-risk patients could reduce the incidence of LTS.
To describe iatrogenic laryngeal injury and identify its risk factors in recurrent respiratory papillomatosis (RRP) patients receiving surgical care.
Case-control.
Tertiary care academic hospital in ...a metropolitan area.
Charts of patients with RRP seen at our institution from January 2002 to December 2022 were reviewed. Patients were separated into 2 cohorts based upon whether they experienced any form of iatrogenic laryngeal injury-including anterior commissure synechiae, vocal cord scar, reduced vocal fold pliability, vocal fold motion impairment, and glottic and/or subglottic stenosis. Adjusted logistic regressions were performed to identify factors associated with iatrogenic laryngeal injury.
Of 199 RRP patients, 133 (66.8%) had identifiable iatrogenic laryngeal injury. The most common injuries were anterior commissure synechiae (n = 67; 50.4%) and reduced vocal fold pliability (n = 54; 40.6%). On a multivariate logistic regression, patients with diabetes mellitus (adjusted odds ratio aOR 95% confidence interval CI: 2.99 1.02, 8.79; P = .04) and who received at least 10 surgeries lifetime (aOR 95% CI: 14.47 1.70, 123.19; P = .01) were at increased risk for iatrogenic laryngeal injury, whereas receiving less than 5 surgeries (aOR 95% CI: 0.21 0.09, 0.51; P < .001) was found to be protective. When treating the lifetime number of surgeries as a continuous variable, a greater number of surgeries was a significant risk factor for iatrogenic laryngeal injury (aOR 95% CI: 1.32 1.14, 1.53; P < .001).
These results suggest the importance of strict glucose control for diabetic patients receiving RRP surgical care, and emphasize the clinical need to identify medical therapies to decrease RRP surgical frequency for patients.
Animal models for laryngotracheal stenosis (LTS) are critical to understand underlying mechanisms and study new therapies. Current animal models for LTS are limited by small airway sizes compared to ...human. The objective of this study was to develop and validate a novel, large animal ovine model for LTS.
Sheep underwent either bleomycin-coated polypropylene brush injury to the subglottis (n = 6) or airway stent placement (n = 2) via suspension microlaryngoscopy. Laryngotracheal complexes were harvested 4 weeks following injury or stent placement. For the airway injury group, biopsies (n = 3 at each site) were collected of tracheal scar and distal normal regions, and analyzed for fibrotic gene expression. Lamina propria (LP) thickness was compared between injured and normal areas of trachea.
No mortality occurred in sheep undergoing airway injury or stent placement. There was no migration of tracheal stents. After protocol optimization, LP thickness was significantly increased in injured trachea (Sheep #3: 529.0 vs. 850.8 um; Sheep #4: 933.0 vs. 1693.2 um; Sheep #5: 743.7 vs. 1378.4 um; Sheep #6: 305.7 vs. 2257.6 um). A significant 62-fold, 20-fold, 16-fold, 16-fold, and 9-fold change of COL1, COL3, COL5, FN1, and TGFB1 was observed in injured scar specimen relative to unaffected airway, respectively.
An ovine LTS model produces histologic and transcriptional changes consistent with fibrosis seen in human LTS. Airway stent placement in this model is safe and feasible. This large airway model is a reliable and reproducible method to assess the efficacy of novel LTS therapies prior to clinical translation.
N/A Laryngoscope, 2024.
Objective(s)
Tracheostomy‐associated granulation tissue is a common, recurrent problem occurring secondary to chronic mucosal irritation. Although granulation tissue is composed of predominantly ...innate immune cells, the phenotype of monocytes and macrophages in tracheostomy‐associated granulation tissue is unknown. This study aims to define the myeloid cell population in granulation tissue secondary to tracheostomy.
Methods
Granulation tissue biopsies were obtained from 8 patients with tracheostomy secondary to laryngotracheal stenosis. Cell type analysis was performed by flow cytometry and gene expression was measured by quantitative real‐time polymerase chain reaction. These methods and immunohistochemistry were used to define the monocyte/macrophage population in granulation tissue and were compared to tracheal autopsy control specimens.
Results
Flow cytometry demonstrated macrophages (CD45+CD11b+) and monocytes (CD45+FSClowSSClow) represent 23.2 ± 6% of the granulation tissue cell population. The M2 phenotype (CD206) is present in 77 ± 11% of the macrophage population and increased compared to the M1 phenotype (p = 0.012). Classical monocytes (CD45+CD14highCD16low) were increased in granulation tissue compared to controls (61.2 ± 7% and 30 ± 8.5%, p = 0.038). Eighty‐five percent of macrophages expressed pro‐inflammatory S100A8/A9 and 36 ± 4% of macrophages co‐localized CD169, associated with tissue‐resident macrophages. M2 gene expression (Arg1/CD206) was increased in granulation tissue (3.7 ± 0.4, p = 0.035 and 3.5 ± 0.5, p = 0.047) whereas M1 gene expression (CD80/CD86) was similar to controls (p = 0.64, p = 0.3). Immunohistochemistry of granulation tissue demonstrated increased cells co‐localizing CD11b and CD206.
Conclusions
M2 macrophages are the dominant macrophage phenotype in tracheostomy‐associated granulation tissue. The role of this cell type in promoting ongoing inflammation warrants future investigation to identify potential treatments for granulation tissue secondary to tracheostomy.
Level of Evidence
3 Laryngoscope, 133:2346–2356, 2023
In patients with indwelling tracheostomy, granulation tissue is a common, recurrent problem that may lead to multiple surgeries, difficulties with decannulation, and even wound contracture leading to stenosis at the site of prosthesis. This study demonstrates that alternatively activated M2 macrophages are increased in airway granulation tissue as determined by gene expression analysis of canonical biomarkers and cell surface antigens assessed by flow cytometry and immunohistochemistry. The monocyte cell populations associated with granulation tissue are predominantly classical subtype and the majority of macrophages were positive for pro‐inflammatory marker S100A8/A9 with 36% of macrophages co‐localizing the biomarker CD169+, highlighting these cell population as potential therapeutic targets for airway granulation tissue.
Objectives (1) Develop a novel method for serial assessment of gene and protein expression in laryngotracheal stenosis (LTS). (2) Assess cytokine expression and determine an immunophenotype in LTS. ...Study Design A matched comparison of endolaryngeal brush biopsy samples from laryngotracheal scar and normal airway. Setting Tertiary care hospital, 2015-2016. Methods Brush biopsy specimens of laryngotracheal scar and normal trachea were obtained from 17 patients with LTS at the time of operating room dilation and were used for protein and RNA extraction. Gene expression of the T
1 cytokine interferon γ (INF-γ), T
2 cytokine interleukin 4 (IL-4), transforming growth factor β, and collagen 1 (Coll1) was quantified with quantitative real-time polymerase chain reaction. Cytokine analysis was performed with flow cytometry with a cytometric bead array. Results LTS specimens demonstrated a 13.68-fold increase in Coll1 gene expression versus normal ( P < .001, N = 17). Additionally, IL-4 gene expression showed a 3.76-fold increase ( P < .001, N = 17) in LTS scar. When stratified into iatrogenic LTS and idiopathic subglottic stenosis cohorts, INF-γ gene expression was significantly increased in idiopathic subglottic stenosis ( P = .011). Soluble cytokine measurements were below the limit of detection for reliable quantification and thus could not be assessed. Conclusions Brush biopsies from LTS samples can be successfully utilized for RNA extraction and demonstrate the expected increase in Coll1 gene expression associated with LTS. Preliminary gene expression suggests that abnormal collagen production may be mediated by the T
2 cytokine IL-4 and that increased INF-γ expression may represent a key difference between iatrogenic LTS and idiopathic subglottic stenosis. Further analysis of soluble cytokines is needed to confirm these findings.
Objective
Characterize and quantify epithelium in multiple etiologies of laryngotracheal stenosis (LTS) to better understand its role in pathogenesis.
Study Design
Controlled in vitro cohort study.
...Methods
Endoscopic brush biopsy samples of both normal (non‐scar) and scar were obtained in four patients with idiopathic subglottic stenosis (iSGS) and four patients with iatrogenic LTS (iLTS). mRNA expression of basal, ciliary, and secretory cell markers were evaluated using quantitative PCR. Cricotracheal resection tissue samples (n = 5 per group) were also collected, analyzed using quantitative immunohistochemistry, and compared with rapid autopsy tracheal samples.
Results
Both iSGS and iLTS‐scar epithelium had reduced epithelial thickness compared with non‐scar control epithelium (P = .0009 and P = .0011, respectively). Basal cell gene and protein expression for cytokeratin 14 was increased in iSGS‐scar epithelium compared with iLTS or controls. Immunohistochemical expression of ciliary tubulin alpha 1, but not gene expression, was reduced in both iSGS and iLTS‐scar epithelium compared with controls (P = .0184 and P = .0125, respectively). Both iSGS and iLTS‐scar had reductions in Mucin 5AC gene expression (P = .0007 and P = .0035, respectively), an epithelial goblet cell marker, with reductions in secretory cells histologically (P < .0001).
Conclusions
Compared with non‐scar epithelium, the epithelium within iSGS and iLTS is morphologically abnormal. Although both iSGS and iLTS have reduced epithelial thickness, ciliary cells, and secretory cells, only iSGS had significant increases in pathological basal cell expression. These data suggest that the epithelium in iSGS and iLTS play a common role in the pathogenesis of fibrosis in these two etiologies of laryngotracheal stenosis.
Setting
Tertiary referral center (2017–2020).
Level of Evidence
NA Laryngoscope, 132:2194–2201, 2022
Iatrogenic laryngotracheal stenosis (iLTS) is the pathologic narrowing of the glottis, subglottis, and/or trachea secondary to intubation or tracheostomy related injury. Patients with type 2 diabetes ...mellitus (T2DM) are more likely to develop iLTS. To date, the metabolomics and phenotypic expression of cell markers in fibroblasts derived from patients with T2DM and iLTS are largely unknown.
Controlled in vitro cohort study.
Tertiary referral center (2017-2020).
This in vitro study assessed samples from 6 patients with iLTS who underwent surgery at a single institution. Fibroblasts were isolated from biopsy specimens of laryngotracheal scar and normal-appearing trachea and compared with controls obtained from the trachea of rapid autopsy specimens. Patients with iLTS were subcategorized into those with and without T2DM. Metabolic substrates were identified by mass spectrometry, and cell protein expression was measured by flow cytometry.
T2DM iLTS-scar fibroblasts had a metabolically distinct profile and clustered tightly on a Pearson correlation heat map as compared with non-T2DM iLTS-scar fibroblasts. Levels of itaconate were elevated in T2DM iLTS-scar fibroblasts. Flow cytometry demonstrated that T2DM iLTS-scar fibroblasts were associated with higher CD90 expression (Thy-1; mean, 95%) when compared with non-T2DM iLTS-scar (mean, 83.6%;
= .0109) or normal tracheal fibroblasts (mean, 81.1%;
= .0042).
Scar-derived fibroblasts from patients with T2DM and iLTS have a metabolically distinct profile. These fibroblasts are characterized by an increase in itaconate, a metabolite related to immune-induced scar remodeling, and can be identified by elevated expression of CD90 (Thy-1) in vitro.
Objectives
Idiopathic subglottic stenosis (iSGS) is an inflammatory process leading to fibrosis and narrowing of the laryngotracheal airway. There is variability in patient response to surgical ...intervention, but the mechanisms underlying this variability are unknown. In this pilot study, we measure expression of candidate targets at the mucosal surface of the subglottis in iSGS patients. We aim to identify putative biomarkers for iSGS that provide insights into the molecular basis of disease progression, yield a gene signature for the disease, and/or predict a response to therapy.
Study Design
In vitro comparative study of human cells.
Methods
Levels of candidate transcripts and proteins were measured in healthy and stenotic laryngotracheal tissue specimens taken from the mucosal surface in 16 iSGS patients undergoing endoscopic balloon dilation. Pre‐ and post‐operative pulmonary function test and patient reported voice and breathing outcomes were also assessed. Unsupervised clustering was used to define patient subgroups based on expression profile.
Results
Pulmonary function and voice and breathing outcome metrics demonstrated significant post‐operative improvement. Transcript levels of αSMA, CCL2, COL1A1, COL3A1, FN1, IFNG, and TGFB1 and protein levels of CCL2, IFNG, and IL‐6 were significantly upregulated in stenotic as compared to healthy tissues. Marked heterogeneity was observed in the patterns of expression of candidate markers across individuals and tissue types. Patient subgroups defined by expression profile did not show a statistically significant difference in dilation interval.
Conclusion
Pro‐inflammatory and pro‐fibrotic pathways are significantly upregulated along the mucosal surface of stenotic laryngotracheal tissues, and CCL2 and IFNG merit further investigation as potential iSGS biomarkers.
Level of Evidence
4 Laryngoscope, 131:342–349, 2021
Idiopathic subglottic stenosis (iSGS) is a debilitating extrathoracic obstruction involving the lower laryngeal and upper tracheal airway. It arises without a known antecedent injury or associated ...disease process. iSGS is a fibrotic disease marked histologically by excessive accumulation of fibrous connective tissue components of the extracellular matrix (ECM, i.e., collagen and fibronectin) in inflamed tissue, which leads to airway obstruction and clinical dyspnea. Diverse diseases in divergent organ systems are associated with fibrosis, suggesting common pathogenic pathways. One of the most common is sustained host inflammation. Recent investigations focusing on the inflammatory response associated with iSGS have sought to characterize the immunophenotype and cytokine profile of the airway scar in iSGS. While the role of the immune response as inciting event in iSGS remains unresolved, the centrality of an active immune response to the observed subglottic tissue remodeling is becoming more defined.
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