Alveolar capillary dysplasia complicated by subglottic stenosis.

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is an interstitial lung disease. In ACDMPV, respiratory impairment with severe pulmonary hypertension occurs from the early hours of life. Anomalies in the cardiovascular, gastrointestinal and genitourinary systems have been reported. However, little is known about upper airway abnormalities. We encountered a genetically diagnosed ACDMPV infant who presented with subglottic and bronchial stenosis. The prenatal diagnosis was hypoplastic left heart syndrome. Her respiratory condition worsened at 16 hours of life. We found subglottic stenosis when intubating. She died on day 7. Autopsy imaging with CT scan showed bilateral main bronchial stenosis. Chromosomal microarray revealed a 531 kb deletion in chromosome 16q24.1, including FOXF1.

ANCA-negative granulomatosis polyangiitis: an airway emergency.

Granulomatosis polyangiitis (GPA) is an autoimmune condition causing inflammation of small blood vessels. It is a rare disorder that may affect various parts of the body. The diagnosis is often based on clinical examination, laboratory investigations and tissue biopsy. In about 10-20% of patients, the anti-neutrophilic cytoplasmic antibody (ANCA) can be negative, and histology maybe inconclusive, which can lead to diagnostic uncertainty. Failure to treat vasculitis can lead to morbidity and even mortality. We present a case report of a gentleman who was presented with an airway emergency with inflammation of the nasal cavity and subglottic involvement amounting to airway stenosis. His ANCA was negative and tissue biopsy from the subglottis was inconclusive. He underwent urgent dilatation of his airway, local therapies to the nose and was commenced on 10 cycles of cyclophosphamide. A follow-up of over 4 years has not shown any relapse of his disease clinically or biochemically. We discuss the clinical findings, diagnostic dilemma and multidisciplinary management of this life-threatening condition.

Endoscopic Anterior Laryngotracheal Reconstruction.

This article introduces a new endoscopic technique for anterior laryngotracheal reconstruction (LTR) using costal rib cartilage grafting in a 2-year-old patient with acquired Grade III subglottic stenosis. The procedure involves an endoscopic incision in the cricoid cartilage's anterior midline and successful outcomes were achieved without complications. The study emphasizes the benefits of this approach, such as reduced hospital stays, shorter operation time, and decreased scarring, but acknowledges the necessity for further human trials to validate its effectiveness in treating different grades of laryngeotracheal stenosis. Laryngoscope, 134:4770-4773, 2024.

Characterizing Dysphonia After Pediatric Open Airway Reconstruction: Systematic Review and Meta-Analysis.

BACKGROUND: Pediatric laryngotracheal stenosis often requires open airway reconstruction. While these surgeries establish an airway for adequate ventilation, many patients develop subsequent dysphonia. Numerous studies have reported outcomes related to voice. OBJECTIVE: This study aims to evaluate dysphonia in pediatric patients following open airway reconstruction, focusing on acoustic parameters, perceptual voice quality, and voice-related quality of life. METHODS: A comprehensive search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines across 6 databases identified articles involving pediatric patients who underwent open airway reconstruction and reported postoperative vocal acoustic parameters, perceptual voice quality, voice-related quality of life, or vocal mechanics. Articles were assessed for bias risk, and common outcomes were synthesized qualitatively and quantitatively using meta-analyses. RESULTS: Among 4089 articles, 21 were included, involving 497 pediatric patients. Laryngotracheoplasty was the most common procedure followed by cricotracheal resection. The Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scale was frequently used to assess voice quality, with a mean score of 55.6 [95% confidence intervals (CIs): 47.9-63.3]. Voice-related quality of life was measured using the pediatric Voice Handicap Index (pVHI) and Pediatric Voice-Related Quality of Life Survey, with mean scores of 35.6 (95% CI: 21.4-49.7) and 83.7 (95% CI: 74.1-93.2), respectively. The fundamental frequency was 210.5 (95% CI: 174.6-246.3). Other common findings included supraglottic phonation, anterior commissure blunting, posterior glottic diastasis, and abnormal vocal cord mobility. CONCLUSION: Pediatric patients experiencing dysphonia after open airway reconstruction exhibited moderately decreased voice quality and reduced voice-related quality of life. However, there was inconsistency in study protocols and outcome measures used. Preserving voice quality during airway reconstruction is crucial to avoid negative impacts on quality of life.

[The use of the dura mater at the final stage of reconstructive plastic surgical treatment of cicatricial stenosis of the larynx and trachea]. / Ispol'zovanie tverdoi mozgovoi obolochki pri zaklyuchitel'nom etape rekonstruktivno-plasticheskogo operativnogo lecheniya rubtsovogo stenoza gortani i trakhei.

The article presents an analysis of the plastic reconstructive surgery effectiveness for patients with an extended tracheal defect using an allograft based on the dura mater (DM) at the final stage of surgical treatment of laryngeal and tracheal cicatricial stenosis. The study included 20 patients with cicatricial stenosis of the larynx and trachea, who were previously performed plastic reconstructive treatment with scar tissue excision in the lumen of the respiratory tract and restoration of the supporting frame of the larynx and trachea using allografts based on costal allocartilage. The age of the patients ranged from 21 to 54 years, the duration of the disease was from 1 to 5 years. After a standard clinical and laboratory examination, with a mandatory video endoscopic examination of the larynx and trachea, multislice computed tomography of the larynx and trachea, patients underwent plastic closure of the tracheal defect using DM. Dynamic outpatient monitoring was carried out once a week for 1 month, once a month for 3 months, control examination was done 6 months after surgical treatment. The results of the study demonstrated a full-fledged social and labor rehabilitation of all 20 patients after the final stage of surgical treatment using DM, the absence of rejection reaction and migration of allo-implantation material, the preserved lumen of the larynx and trachea with a rigid supporting skeleton and the absence of anterior tracheal wall floatation. The use of DM as an additional strengthening of the anterior tracheal wall for patients with deficiency of muscular aponeurotic tissues and more than 2 cm size tracheal defect is highly effective at the final stage of surgical treatment for plastic closure of the tracheal defect.

Subcutaneous fixation model for complex stenting of recurrent laryngotracheal stenosis.

BACKGROUND: A straight silicone stent can be used to treat proximal benign tracheal stenosis in non-surgical candidates. However, stent migration is a common complication when placed at a particular location and can lead to major complications. This case series of laryngotracheal stenosis reports a fixation method for straight silicone stents in the subglottic trachea (Stage 3 of the McCaffrey classification). METHODS: The medical charts of these patients scheduled for straight silicone stent placement with suture fixation between 2014 and 2020 at the CHU UCL Namur Hospital (Belgium) were retrospectively reviewed. The procedure was performed using a rigid bronchoscope. Details of the procedure were obtained from medical records. RESULTS: This case series included six patients (males: 4, females: 2). The median patient age was 59 years. Two suture fixations were placed following previous silicone stent migration episodes, whereas the others were placed proactively to avoid this risk. All fixations were performed by the device Freka® Pexact II ENFIt®, originally developed for gastropexy in endoscopic gastrostomy. The sutures were subcutaneously buried. CONCLUSIONS: During the 6-month follow-up period, complications such as fixation issues and stent migration were reported despite the off-label use of the treatment. The straight silicone stent fixation technique used in this case series was simple and effective for securing the stent in upper benign tracheal stenosis.

Using Machine Learning for Endoscopic Detection of Low-Grade Subglottic Stenosis: A Proof of Principle.

The current study trains, tests, and evaluates a deep learning algorithm to detect subglottic stenosis (SGS) on endoscopy. A retrospective review of patients undergoing microlaryngoscopy-bronchoscopy was performed. A pretrained image classifier (Resnet50) was retrained and tested on 159 images of airways taken at the glottis, 106 normal-sized airways, and 122 with SGS. Data augmentation was performed given the small sample size to prevent overfitting. Overall model accuracy was 73.3% (SD: 3.8). Precision and recall for stenosis were 77.3% (SD: 4.0) and 72.7 (SD: 4.0). F1 score for the detection of stenosis was 0.75 (SD: 0.04). Precision and recall for normal-sized images were lower at 69% (SD: 4.35) and 74% (SD: 4), with an F1 score of 0.71 (SD: 0.04). This study demonstrates that an image classification algorithm can identify SGS on endoscopic images. Work is needed to improve diagnostic accuracy for eventual deployment of the algorithm into clinical care.

Local adjuncts to minimally invasive endoscopic interventions for benign laryngotracheal stenosis: a meta-analysis.

BACKGROUND: Benign laryngotracheal stenosis is widely managed with minimally invasive endoscopic interventions, such as laser incision or excision scar, and dilation. However, various endoscopic treatments are significantly associated with a high recurrence rate. Local auxiliary measures, including inhalation of steroids, injection of steroids, and local topical application of mitomycin C, have been studied in order to increase the success rate. PURPOSE: To compare the efficacy of endoscopic treatments with and without local adjuncts in patients with benign laryngotracheal stenosis, and analyze their clinical outcomes, recurrence, and complications. METHODS: In the meta-analysis, databases including PubMed, EMBASE, OVID, and Web of Science were searched for papers comparing the outcomes of adjunct therapy with non-adjunct therapy in patients with laryngotracheal stenosis. The duplicate publications, reviews, comments or letters, conference abstracts, and case reports were excluded. The random effect model was used for assessing the pooled risk estimates. RESULTS: Eight studies (1204 cases) referring to two prospective randomized controlled studies, two prospective cohort studies, and four retrospective cohort studies were ultimately included in the meta-analysis. Three delivery modes of adjuncts were identified, including intralesion steroid injection (n = 2), inhaled steroid (n = 2), and topical application of mitomycin C (n = 4). The decreased risk estimates of recurrence rate were detected in patients receiving endoscopic treatments with steroid injection or inhaled steroid, compared with endoscopic interventions alone (P < 0.05). Additionally, patients undergoing adjunct therapies had lower risk estimates of recurrence, compared to those receiving endoscopic procedures alone (P < 0.05), based on the subgroup of prospective cohort studies, subglottis, Mayer-Cotton scale of I-II degree, and stenosis length of < 3 cm. The high heterogeneity of the pooling risk estimates perhaps was due to factors of auxiliary drug, clinical characteristics of patients, and methodology. No discernible difference in the incidence of complication was identified. CONCLUSIONS: Local application of steroids to minimally invasive interventions appear to reduce the recurrence rate of laryngotracheal stenosis. Various adjuncts available, including steroids and mitomycin C, appear to be safe and associated with a low risk estimate of adjuncts-specific complication rate. High quality multi-center randomized controlled studies are needed, with sufficient periods for follow-up and subjective and objective outcome indicators, to properly evaluate the efficacy, safety, and cost-effectiveness of adjuvant drugs.

The impact of previous endoscopic treatments on functional outcome after cricotracheal resection.

OBJECTIVES: Treatment options for benign subglottic stenosis include endoscopic techniques or open surgery. Although endoscopic treatment is less invasive, a considerable proportion of patients develop recurrent stenosis. Endoscopic pretreatments do not exclude patients from a later surgical repair; however, the impact of previous endoscopic treatment attempts on functional outcome after open surgery is unknown. METHODS: All patients, who received a cricotracheal resection (CTR) between January 2017 and June 2023 at the Department of Thoracic Surgery, Medical University of Vienna, were included in this retrospective study. Patient characteristics, surgical variables and postoperative outcome including a detailed functional assessment were analysed. RESULTS: A total of 65 patients received a CTR during the study period, of which 40 were treatment naïve and 25 had a median of 2 (range 1-9) endoscopic pretreatments. Less-invasive voice-sparing CTR or standard CTR were more often possible in treatment-naïve patients. In contrary, pretreated patients regularly required extended procedures (P = 0.049). Three or more endoscopic treatments resulted in a significantly lower mean fundamental frequency (F0) after open repair (P = 0.048). In addition, a trend towards smaller mean sound pressure levels, a higher voice handicap index, higher impairments in RBH scores (roughness, breathing and hoarseness) and a higher dysphagia severity index was found in pretreated patients. The respiratory outcome after surgery was comparable between both groups. CONCLUSIONS: Multiple endoscopic pretreatments lead to worse voice quality after CTR. The impact of prior endoscopic treatment before surgical repair should be considered when discussing treatment options with patients suffering from subglottic stenosis.

Symptom-Free Intervals Following Laser Wedge Excision for Recurrent Idiopathic Subglottic Stenosis.

OBJECTIVE: Analyze the duration of symptom-free intervals following laser wedge excision (LWE) for recurrent idiopathic subglottic stenosis (iSGS). Secondary aim includes evaluating the influence of patient-related or disease factors. STUDY DESIGN: Retrospective review. SETTING: Tertiary center. METHODS: Review of iSGS patients who underwent LWE between 2002 and 2021. LWE patients without prior airway surgery were labeled LWE primary (LWEP) and those with prior history of dilation were labeled LWE secondary (LWES). A conditional frailty repeated events model was used to analyze the median time to recurrence (MTR) for each nth recurrence. Secondary analysis included stratification by use of medical therapy and initial preoperative characteristics of scar (Myer-Cotton grade, distance between the glottis and superior-most aspect of scar, DGS; length of scar, DL). RESULTS: Two hundred and ten iSGS patients underwent LWE (131 LWEP, 79 LWES). The proportion of patients experiencing at least 1, 3, 6, and 12 recurrences, respectively, was 68.0% (n = 143), 40.7% (n = 85), 20.0% (n = 42), and 5.2% (n = 11). There was exponential time-shortening from the 1st to 12th recurrence (P < .0001). While MTR was 4.1 years after the first LWE, this fell to 2.8, 1.7, 1.0, and 0.7 years for the 2nd, 3rd, 6th, and 12th recurrences. Furthermore, LWEP patients experienced longer MTR than LWES counterparts within the first 6 recurrences (P < .01). There was no significant relationship between intersurgical interval and medication adherence, DL, DGS, or grade for recurrences beyond the first (P = .207, P = .20, P = .43, P = .16). CONCLUSION: Symptom-free intervals in iSGS shorten with each subsequent recurrence and LWE. The difference in MTR between LWEP and LWES groups was significant within the first 6 recurrences with LWEP having longer MTR.

Degrees of Inflammation in the Treatment of Subglottic Stenosis in a Rabbit Model: Histopathological Assessment of a Novel Bioabsorbable Ultra-high Ductility Magnesium Alloy Stent.

OBJECTIVE: Utilizing a novel histopathological scoring system and subglottic stenosis (SGS) rabbit model, we aimed to compare degrees of inflammation and severity of narrowing in the subglottis between two minimally invasive therapeutic modalities: endoscopic balloon dilation (EBD) alone versus EBD with placement of a bioabsorbable ultra-high ductility magnesium (UHD-Mg) alloy stent. METHODS: SGS was induced endoscopically via microsuspension laryngoscopy in 23 New Zealand white rabbits. The control group (n = 11) underwent EBD alone, the study arm (n = 12) underwent EBD with implantation of bioabsorbable UHD-Mg alloy stents. Rabbits were euthanized at 2-, 3-, and 6-weeks after SGS induction, coinciding with wound healing stages. Using Optical Coherence Tomography (OCT), cross-sectional areas of airways were compared to calculate the mean percentage of intraluminal area at sequential time points. A novel histopathological scoring system was used to analyze frozen sections of laryngotracheal complexes. The degree of inflammation was quantified by scoring changes in inflammatory cell infiltration, epithelial ulceration/metaplasia, subepithelial edema/fibrosis, and capillary number/dilation. Univariate analysis was utilized to analyze these markers. RESULTS: We found rabbits implanted with the bioabsorbable UHD-Mg alloy stent had statistically significantly higher scores in categories of hyperplastic change (stents vs controls: 1.48 vs 0.46 p < 0.001), squamous metaplasia (22 vs 5 p < 0.001), and neutrophils/fibrin in lumen (31 vs 8, p < 0.001). Rabbits who received EBD alone had higher scores of subepithelial edema and fibrosis (2.70 vs 3.49, p < 0.0256). The stented rabbits demonstrated significantly increased mean percent stenosis by intraluminal mean area compared to controls at 2 weeks (88.56 vs 58.98, p = 0.032), however at all other time points there was no significant difference between intraluminal subglottic stenosis by mean percent stenosis area. DISCUSSION: Rabbits with SGS treated with UHD-Mg alloy stents demonstrated histopathologic findings suggestive of lower levels of tracheal fibrosis. This could indicate a reduced tendency towards the development of stenosis when compared to EBD alone. There was not a difference in luminal size between stent and non-stented rabbits at the six-week end point. Histologically, however, overall the use of bioabsorbable UHD-Mg alloy stenting elicited a greater tissue response at the level of the superficial mucosa rather than fibrosis of the lamina propria seen in the stented rabbits. This suggests more favorable healing and less of a tendency towards fibrosis and stenosis even though there may not be a benefit from a luminal size standpoint during this early healing period. Compared to known complications of currently available non-bioabsorbable metal or silicone-based stents, this proof-of-concept investigation highlights the potential use of a novel biodegradable UHD-Mg stent as a therapeutic modality for pediatric SGS.

Mapping quality of life after balloon dilatation in subglottic stenosis using Dyspnea index and Short Form Health Survey-36.

PURPOSE: An accurate diagnosis and proper treatment plan are required to restore an adequate patent airway in fibrotic subglottic stenosis (SGS). Currently, the definitive treatment entails single-stage balloon dilatation with steroid injections. The primary aim was to evaluate successful airway restoration and general quality of life in cases with SGS in northern Sweden using robust patient reported outcomes. METHODS: All participants with need of surgical treatment due to SGS that had been referred to the department of otorhinolaryngology, University Hospital of Umeå from September 2020 to August 2023 was included. Exclusion criteria included malignant, extrathoracic or cartilaginous cause, age < 18 years, or incompetent to sign consent documents. We assessed the patient-reported outcome measures pre- as well as 3 months postoperatively. RESULTS: Of the 40 cases fulfilling the eligibility criteria's, 33 cases completed the Dyspnea index (DI) and the short form health survey (SF-36) pre- as well as 3 months post-operatively. Receiver operating characteristics showed significant improvement in DI as well as in SF 36 scores post-operatively. CONCLUSIONS: Evaluation of balloon dilatation in SGS in this cohort follow-up analysis shows clear improvement in patient quality of life using robust PROM 3 months postoperatively, ensuring the use of a safe and well-tolerated procedure.

Reconstructive Surgery of the Laryngotracheal Junction. / Rekonstruktive Chirurgie des laryngo-trachealen Übergangs.

The laryngotracheal junction is an anatomical region with special pathophysiological features. This review presents clinical pictures and malformations that manifest pre-dilectively at this localisation in children and adolescents as well as in adults. The diagnostic procedure is discussed. The possibilities of surgical reconstruction are presented depending on the pathology and age of the patient.

Congenital glottic stenosis as a clinical manifestation of FREM1-associated disorders in a neonate with respiratory distress and aphonia.

A female infant born at 38 weeks and 2 days via induced vaginal delivery was admitted to the neonatal intensive care unit for respiratory distress soon after birth. Noted to have aphonia on examination, the patient underwent direct laryngoscopy and was diagnosed with an anterior glottic web and subglottic stenosis. The patient underwent a genetic workup including whole exome sequencing which resulted in a diagnosis of a FREM1-associated disorder. Congenital glottic webs and subglottic stenoses have not been previously described as clinical manifestations of FREM1-associated disorders.

Endoscopic posterior cricoid split with costal cartilage graft placement in patients under one year of age.

Endoscopic posterior cricoid split and costal rib graft placement (EPCSCG) is an important tool in enlarging the glottic and subglottic airway, both of which can be disproportionally affected in the small airways of neonates and early infants. We present a series of 8 patients under the age of one who successfully underwent EPCSCG, with 7/8 patients avoiding tracheostomy entirely. Of these patients, the indication for EPCSCG was isolated bilateral vocal fold immobility (6/8), bilateral vocal fold immobility with subglottic stenosis (1/8), and isolated subglottic stenosis (1/8). EPCSCG can be safely applied to select patients less than one year of age.

Endoscopic balloon dilatation for pediatric subglottic stenosis: a meta-analysis of successful outcomes.

OBJECTIVES: The primary goal of this study was to systematically identify all relevant published articles on the use of primary endoscopic balloon dilation for the management of pediatric patients with subglottic stenosis, critically assess the technique's success, and determine which patients are the best candidates for the procedure. METHODOLOGY: This was a systematic review and meta-analysis that aimed to investigate the use and success rate of EBD for treating pediatric SGS. An electronic systematic literature search of three major databases, PubMed, EBSCO, and Web of Science&MEDLINE through Clarivate, was conducted to include the eligible articles. RESULTS: A total of 14 unique studies were included in the final analysis, with 473 cases of pediatric SGS. The pooled success rate of EBD in treatment of pediatric SGS was 76% (k = 14 studies, 95% confidence interval [CI] = 0.65-0.86, P < 0.001, Q test for heterogeneity = 0.03, P < .001, I2 = 91%). CONCLUSIONS: We reported a high success rate of EBD in treating pediatric SGS. The reported complications were uncommon, although they can be serious and life threatening. The intensity of SGS may be related to the likelihood of therapy failure.

Impact of BMI on Dyspnea and Need for Surgical Intervention in Bilateral Vocal Fold Immobility.

OBJECTIVE: Bilateral vocal fold paralysis (BVFP) and posterior glottic stenosis (PGS) are causes of bilateral vocal fold immobility (BVFI) and may cause shortness of breath, stridor, and need for surgical intervention. Although increased body mass index (BMI) is associated with restrictive breathing patterns in patients with normal upper airways, it is unclear how BMI impacts dyspnea and need for surgical intervention in BVFI patients. STUDY DESIGN: Retrospective cohort study. SETTING: Three tertiary academic centers in the United States. METHODS: Demographics, BMI, Dyspnea Index (DI), etiology, presence of tracheostomy and surgical intervention (dilation, tracheostomy, cordotomy, arytenoidectomy, open reconstruction) were collected. Primary outcomes included dyspnea measured by DI and need for surgery to improve airway. Linear regressions were performed to assess continuous outcomes. Mann-Whitney U-test was utilized to assess categorical outcomes. RESULTS: Among 121 patients, 52 presented with BVFP and 69 with PGS. Previous neck surgery was the most common cause of BVFI (40.2%). 44.3% of patients received a tracheostomy. Through multivariate linear regression, increased BMI was significantly associated with increased DI in the entire cohort (ß = .43, P = .016). Increased BMI was also associated with need for any surgical intervention (odds ratio [OR] = 1.07, 95% confidence interval [CI] = [1.01-1.13]) in the overall cohort. When stratifying our data, BMI was only significantly associated with DI in BVFP (ß = .496) and need for surgical intervention in PGS (OR = 1.11, 95% CI = [1.01-1.21]), although a positive trend was seen in all analyses. CONCLUSION: Increased BMI may correlate with worsening dyspnea symptoms and need for surgical intervention in patients with BVFI. Weight-loss-related counseling may benefit symptom management.

A Comprehensive Flow Cytometry Panel for Analysis of Idiopathic Subglottic Stenosis.

OBJECTIVE: To present a comprehensive flow cytometry panel for idiopathic subglottic stenosis (iSGS). STUDY DESIGN: Controlled ex vivo cohort study. SETTING: Tertiary care academic hospital in a metropolitan area. METHODS: Flow cytometry and single-cell RNA sequencing were performed on 9 paired normal and scar tissue samples from iSGS patients. Flow cytometry was used to assess the presence of myeloid (CD11b, CD14, CD15, Siglec8), lymphoid (CD3, CD4, CD8, gamma delta [γδ], FOXP3), endothelial (CD31), fibroblast (CD90, SMA), and epithelial (CD326, CK5) markers. RESULTS: On flow cytometry, iSGS scar is characterized by an increased presence of myeloid, lymphoid, endothelial, and fibroblast cell types, but a decreased presence of epithelial cells. In the myeloid lineage, iSGS scar samples demonstrated increased CD11b+ monocytes (P < .001), Siglec8+ eosinophils (P = .03), and CD14+ monocytes (P = .02). In the lymphoid lineage, iSGS scar demonstrated increased CD3+ T-cells (P < .001), CD4+ helper T-cells (P < .001), γδ+ T-cells (P < .001), and FOXP3+ regulatory T-cells (P = .002). iSGS scar exhibited specific increases in CD90+ (P = .04) and SMA+ (P < .001) fibroblasts but decreased CD326+ (E-cadherin) epithelial cells (P = .01) relative to normal samples. CONCLUSION: We present a comprehensive flow cytometry panel for iSGS. This flow panel may serve as a common platform among airway scientists to elucidate the cellular mechanisms underpinning iSGS and other upper airway pathologies. Scar iSGS samples demonstrate a distinct cellular profile relative to normal iSGS specimens, exhibiting increased fibroblast, endothelial, and inflammatory cell types but decreased epithelium.

[Application of acellular dermal matrix in prevention of laryngeal stenosis in glottic carcinoma].

Objective:To investigate the effect of acellular dermal matrix in preventing laryngeal stenosis in glottic carcinoma patients. Methods:Fifty-five patients with glottic carcinoma（T2, T3） from February 2018 to December 2022 were divided into experimental group（28 cases） and control group（27 cases） according to their wishes. Acellular dermal matrix was placed in the operation cavity in the experimental group after laryngofission, while control group 12 cases were sutured by pulling the upper and lower edges, 15 cases were repaired with sternohyoid muscle fascia flap. Results:In the experimental group, 1 case had laryngeal stenosis caused by laryngeal mucosa swelling after operation, and extubated successfully after symptomatic treatment. In the control group, 7 cases had laryngeal stenosis after operation, of which 3 cases were caused by granulation tissue hyperplasia in laryngeal cavity, and extubated after symptomatic treatment. 2 cases extubated after operation suffered from progressive dyspnea during radiotherapy, and underwent tracheotomy again, extubation successful after treatment. 2 cases caused by laryngeal mucosa swelling, after symptomatic treatment, one case was successfully extubated, and one case had long-term intubation. The laryngeal stenosis rate of the experimental group was 3.6%（1/28） , which was lower than control group 25.9%（7/27）, and the therapeutic effect of the experimental group was significantly better than control group （χ²=5.526, P=0.019）. Conclusion:Implanting acellular dermal matrix in the operation cavity of glottic carcinoma can reduce the occurrence of laryngeal stenosis and have satisfactory preventive effect on laryngeal stenosis.